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Special Issue "Chemical and Molecular Approach to Tumor Metastases"

A special issue of International Journal of Molecular Sciences (ISSN 1422-0067). This special issue belongs to the section "Biochemistry".

Deadline for manuscript submissions: closed (31 October 2017)

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Guest Editor
Prof. Dr. Gianni Sava

Department of Life Sciences, University of Trieste, via A. Fleming 22, 34127 Trieste, Italy
Website | E-Mail
Interests: pharmacology; metastasis; solid tumors; metal-based drugs; drug development
Guest Editor
Dr. Alberta Bergamo

Callerio Foundation Onlus, via A. Fleming 22, 34127 Trieste, Italy
E-Mail
Interests: : pharmacology; metastasis; tumor microenvironment; metal-based drugs; integrins

Special Issue Information

Dear Colleagues,

Malignant tumors develop distant metastases, e.g., small clusters of cells that detach from the primitive site and colonize distant organs and tissues. Unlike the primary masses, metastases are often difficult to fully eradicate by surgery ablation and are almost always the primary object of chemo- and/or immune-therapies. The presence of metastases at tumor diagnosis is responsible for the unfavorable prognosis and of relapses even after initially successful tumor therapies. The lack of success of chemo- and immune-therapy approaches depends on many factors among which, the inadequate capacity of the anti-tumor drugs of reaching appropriate concentrations in the organs and tissues involved in the metastatic growth is a major concern. Another factor is the complexity of the metastasis biology and of their molecular behavior, evidencing a population of tumor cells with a genetic compartment different from that of the tumor of origin. The involvement of host cells and factors recruited by the metastatic cells and committed to support the metastatic growth is also an event crucial for the lack of success of the anti-tumor therapy. The knowledge of the molecular biology of metastases is mandatory to support the search for chemical agents to treat the metastatic determinants and to control of the neoplastic disease.

This Special Issue on “Chemical and Molecular Approach to Tumor Metastases” will explore the impact of biology, molecular medicine and chemistry on all aspects related to tumor metastases from the biological and molecular aspects of the metastatic growth, including the relationships between the metastatic cells and the host environment, and the search for druggable determinants useful for the chemical analysis of agents selectively active against tumor metastases.

With the combination of invited reviews and original papers from prominent scientists working on all aspects of molecular medicine and cancer therapy, such as, but not limited to: drug delivery, genomics, chemoprevention, drug discovery, we aim to sample recent progress in molecular and chemical aspects of therapy of malignant tumors. Clinical success studies and evidences of novel compounds are particularly welcome.

Prof. Dr. Gianni Sava

Dr. Alberta Bergamo

Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. International Journal of Molecular Sciences is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • tumor metastasis
  • biology of metastasis
  • genomics of metastasis
  • epigenetics of metastasis
  • dynamics of metastasis
  • metastasis niche
  • microenvironment
  • immunotherapy
  • chemotherapy
  • molecular approaches
  • chemical approaches
  • metastasis druggable targets
  • innovative drugs
  • clinical studies

Published Papers (16 papers)

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Editorial

Jump to: Research, Review

Open AccessEditorial
Chemical and Molecular Approach to Tumor Metastases
Int. J. Mol. Sci. 2018, 19(3), 843; https://doi.org/10.3390/ijms19030843
Received: 1 March 2018 / Revised: 8 March 2018 / Accepted: 12 March 2018 / Published: 14 March 2018
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Abstract
Tumours are not merely masses of abnormally proliferating cancer cells[...] Full article
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Research

Jump to: Editorial, Review

Open AccessArticle
3,3′-Diindolylmethane Suppressed Cyprodinil-Induced Epithelial-Mesenchymal Transition and Metastatic-Related Behaviors of Human Endometrial Ishikawa Cells via an Estrogen Receptor-Dependent Pathway
Int. J. Mol. Sci. 2018, 19(1), 189; https://doi.org/10.3390/ijms19010189
Received: 11 November 2017 / Revised: 2 January 2018 / Accepted: 5 January 2018 / Published: 8 January 2018
Cited by 1 | PDF Full-text (4323 KB) | HTML Full-text | XML Full-text
Abstract
Cyprodinil (CYP) is a pyrimidine amine fungicide that has been extensively used in agricultural areas. 3,3′-Diindolylmethane (DIM) is a derivative of the dietary phytoestrogen, indole-3-carbinol (I3C), which is derived from cruciferous vegetables and considered to be a cancer-preventive phytonutrient agent. In this study, [...] Read more.
Cyprodinil (CYP) is a pyrimidine amine fungicide that has been extensively used in agricultural areas. 3,3′-Diindolylmethane (DIM) is a derivative of the dietary phytoestrogen, indole-3-carbinol (I3C), which is derived from cruciferous vegetables and considered to be a cancer-preventive phytonutrient agent. In this study, the effects of CYP and DIM were examined on the cell viability, invasion, and metastasis of human endometrial cancer cells, Ishikawa, via epithelial mesenchymal transition (EMT). CYP increased the level of cell viability of Ishikawa cells compared to DMSO as a control, as did E2. Ishikawa cells lost cell-to-cell contact and obtained a spindle-shaped or fibroblast-like morphology in response to the application of E2 or CYP by the cell morphology assay. In the cell migration and invasion assay, CYP enhanced the ability of migration and invasion of Ishikawa cells, as did E2. E2 and CYP increased the expressions of N-cadherin and Snail proteins, while decreasing the expression of E-cadherin protein as EMT-related markers. In addition, E2 and CYP increased the protein expressions of cathepsin D and MMP-9, metastasis-related markers. Conversely, CYP-induced EMT, cell migration, and invasion were reversed by fulvestrant (ICI 182,780) as an estrogen receptor (ER) antagonist, indicating that CYP exerts estrogenic activity by mediating these processes via an ER-dependent pathway. Similar to ICI 182,780, DIM significantly suppressed E2 and CYP-induced proliferation, EMT, migration, and invasion of Ishikawa cancer cells. Overall, the present study revealed that DIM has an antiestrogenic chemopreventive effect to withdraw the cancer-enhancing effect of E2 and CYP, while CYP has the capacity to enhance the metastatic potential of estrogen-responsive endometrial cancer. Full article
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Open AccessArticle
In Vivo Imaging of Prostate Cancer Tumors and Metastasis Using Non-Specific Fluorescent Nanoparticles in Mice
Int. J. Mol. Sci. 2017, 18(12), 2584; https://doi.org/10.3390/ijms18122584
Received: 18 October 2017 / Revised: 27 November 2017 / Accepted: 29 November 2017 / Published: 1 December 2017
Cited by 1 | PDF Full-text (3179 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
With the growing interest in the use of nanoparticles (NPs) in nanomedicine, there is a crucial need for imaging and targeted therapies to determine NP distribution in the body after systemic administration, and to achieve strong accumulation in tumors with low background in [...] Read more.
With the growing interest in the use of nanoparticles (NPs) in nanomedicine, there is a crucial need for imaging and targeted therapies to determine NP distribution in the body after systemic administration, and to achieve strong accumulation in tumors with low background in other tissues. Accumulation of NPs in tumors results from different mechanisms, and appears extremely heterogeneous in mice models and rather limited in humans. Developing new tumor models in mice, with their low spontaneous NP accumulation, is thus necessary for screening imaging probes and for testing new targeting strategies. In the present work, accumulation of LipImageTM 815, a non-specific nanosized fluorescent imaging agent, was compared in subcutaneous, orthotopic and metastatic tumors of RM1 cells (murine prostate cancer cell line) by in vivo and ex vivo fluorescence imaging techniques. LipImageTM 815 mainly accumulated in liver at 24 h but also in orthotopic tumors. Limited accumulation occurred in subcutaneous tumors, and very low fluorescence was detected in metastasis. Altogether, these different tumor models in mice offered a wide range of NP accumulation levels, and a panel of in vivo models that may be useful to further challenge NP targeting properties. Full article
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Open AccessArticle
Does Locoregional Chemotherapy Still Matter in the Treatment of Advanced Pelvic Melanoma?
Int. J. Mol. Sci. 2017, 18(11), 2382; https://doi.org/10.3390/ijms18112382
Received: 1 September 2017 / Revised: 3 November 2017 / Accepted: 7 November 2017 / Published: 9 November 2017
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Abstract
Pelvic Melanoma relapse occurs in 15% of patients with loco regional metastases, and 25% of cases do not respond to new target-therapy and/or immunotherapy. Melphalan hypoxic pelvic perfusion may, therefore, be an option for these non-responsive patients. Overall median survival time (MST), stratified [...] Read more.
Pelvic Melanoma relapse occurs in 15% of patients with loco regional metastases, and 25% of cases do not respond to new target-therapy and/or immunotherapy. Melphalan hypoxic pelvic perfusion may, therefore, be an option for these non-responsive patients. Overall median survival time (MST), stratified for variables, including BRAF V600E mutation and eligibility for treatments with new immunotherapy drugs, was retrospectively assessed in 41 patients with pelvic melanoma loco regional metastases. They had received a total of 175 treatments with Melphalan hypoxic perfusion and cytoreductive excision. Among the 41 patients, 22 (53.7%) patients exhibited a wild-type BRAF genotype, 11 of which were not eligible for immunotherapy. The first treatment resulted in a 97.5% response-rate in the full cohort and a 100% response-rate in the 22 wild-type BRAF patients. MST was 18 months in the full sample, 20 months for the 22 wild-type BRAF patients and 21 months for the 11 wild-type BRAF patients not eligible for immunotherapy. Melphalan hypoxic perfusion is a potentially effective treatment for patients with pelvic melanoma loco regional metastases that requires confirmation in a larger multicenter study. Full article
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Open AccessArticle
Differential Functional Roles of ALDH1A1 and ALDH1A3 in Mediating Metastatic Behavior and Therapy Resistance of Human Breast Cancer Cells
Int. J. Mol. Sci. 2017, 18(10), 2039; https://doi.org/10.3390/ijms18102039
Received: 5 September 2017 / Revised: 18 September 2017 / Accepted: 18 September 2017 / Published: 22 September 2017
Cited by 10 | PDF Full-text (2308 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Previous studies indicate that breast cancer cells with high aldehyde dehydrogenase (ALDH) activity and CD44 expression (ALDHhiCD44+) contribute to metastasis and therapy resistance, and that ALDH1 correlates with poor outcome in breast cancer patients. The current study hypothesized that [...] Read more.
Previous studies indicate that breast cancer cells with high aldehyde dehydrogenase (ALDH) activity and CD44 expression (ALDHhiCD44+) contribute to metastasis and therapy resistance, and that ALDH1 correlates with poor outcome in breast cancer patients. The current study hypothesized that ALDH1 functionally contributes to breast cancer metastatic behavior and therapy resistance. Expression of ALDH1A1 or ALDH1A3 was knocked down in MDA-MB-468 and SUM159 human breast cancer cells using siRNA. Resulting impacts on ALDH activity (Aldefluor® assay); metastatic behavior and therapy response in vitro (proliferation/adhesion/migration/colony formation/chemotherapy and radiation) and extravasation/metastasis in vivo (chick choroiallantoic membrane assay) was assessed. Knockdown of ALDH1A3 but not ALDH1A1 in breast cancer cells decreased ALDH activity, and knockdown of ALDH1A1 reduced breast cancer cell metastatic behavior and therapy resistance relative to control (p < 0.05). In contrast, knockdown of ALDH1A3 did not alter proliferation, extravasation, or therapy resistance, but increased adhesion/migration and decreased colony formation/metastasis relative to control (p < 0.05). This is the first study to systematically examine the function of ALDH1 isozymes in individual breast cancer cell behaviors that contribute to metastasis. Our novel results indicate that ALDH1 mediates breast cancer metastatic behavior and therapy resistance, and that different enzyme isoforms within the ALDH1 family differentially impact these cell behaviors. Full article
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Open AccessArticle
SMAD2 Inactivation Inhibits CLDN6 Methylation to Suppress Migration and Invasion of Breast Cancer Cells
Int. J. Mol. Sci. 2017, 18(9), 1863; https://doi.org/10.3390/ijms18091863
Received: 23 May 2017 / Revised: 22 August 2017 / Accepted: 22 August 2017 / Published: 30 August 2017
Cited by 2 | PDF Full-text (2861 KB) | HTML Full-text | XML Full-text
Abstract
The downregulation of tight junction protein CLDN6 promotes breast cancer cell migration and invasion; however, the exact mechanism underlying CLDN6 downregulation remains unclear. CLDN6 silence is associated with DNA methyltransferase 1 (DNMT1) mediated DNA methylation, and DNMT1 is regulated by the transforming growth [...] Read more.
The downregulation of tight junction protein CLDN6 promotes breast cancer cell migration and invasion; however, the exact mechanism underlying CLDN6 downregulation remains unclear. CLDN6 silence is associated with DNA methyltransferase 1 (DNMT1) mediated DNA methylation, and DNMT1 is regulated by the transforming growth factor beta (TGFβ)/SMAD pathway. Therefore, we hypothesized that TGFβ/SMAD pathway, specifically SMAD2, may play a critical role for CLDN6 downregulation through DNA methyltransferase 1 (DNMT1) mediated DNA methylation. To test this hypothesis, we blocked the SMAD2 pathway with SB431542 in two human breast cancer cell lines (MCF-7 and SKBR-3). Our results showed that treatment with SB431542 led to a decrease of DNMT1 expression and the binding activity for CLDN6 promoter. The methylation level of CLDN6 promoter was decreased, and simultaneously CLDN6 protein expression increased. Upregulation of CLDN6 inhibited epithelial to mesenchymal transition (EMT) and reduced the migration and invasion ability of both MCF-7 and SKBR-3 cells. Furthermore, knocked down of CLDN6 abolished SB431542 effects on suppression of EMT associated gene expression and inhibition of migration and invasion. Thus, we demonstrated that the downregulation of CLDN6 is regulated through promoter methylation by DNMT1, which depends on the SMAD2 pathway, and that CLDN6 is a key regulator in the SMAD2/DNMT1/CLDN6 pathway to inhibit EMT, migration and invasion of breast cancer cells. Full article
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Open AccessCommunication
The Differential Distribution of RAPTA-T in Non-Invasive and Invasive Breast Cancer Cells Correlates with Its Anti-Invasive and Anti-Metastatic Effects
Int. J. Mol. Sci. 2017, 18(9), 1869; https://doi.org/10.3390/ijms18091869
Received: 27 July 2017 / Revised: 22 August 2017 / Accepted: 24 August 2017 / Published: 29 August 2017
Cited by 4 | PDF Full-text (1313 KB) | HTML Full-text | XML Full-text
Abstract
Nanoscale secondary ion mass spectrometry (NanoSIMS) combined with transmission electron microscopy (TEM) can be a powerful approach to visualize the exact distribution of drugs at the sub-cellular level. In this work, we exploit this approach to identify the distribution and localisation of the [...] Read more.
Nanoscale secondary ion mass spectrometry (NanoSIMS) combined with transmission electron microscopy (TEM) can be a powerful approach to visualize the exact distribution of drugs at the sub-cellular level. In this work, we exploit this approach to identify the distribution and localisation of the organometallic ruthenium(II)-arene drug Ru(η6-C6H5Me)(pta)Cl2, termed RAPTA-T, in MDA-MB-231 and MCF-7 human breast cancer cells. These cell lines have been chosen because the former cell lines are highly invasive and resistant to most chemotherapeutic agents and the latter ones are very sensitive to hormonal-based therapies. In the MDA-MB-231 cells, RAPTA-T was found to predominantly localise on the cell membrane and to a lesser extent in the nucleolus. These findings are consistent with the previously reported anti-metastatic properties of RAPTA-T and the observation that once internalized RAPTA-T is associated with chromatin. RAPTA-T shows a lack of membrane accumulation on the non-invasive MCF-7 cells, which correlates well with its selective anti-metastatic properties on invasive cell lines. Full article
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Open AccessArticle
Tumor-Stroma Crosstalk in Bone Tissue: The Osteoclastogenic Potential of a Breast Cancer Cell Line in a Co-Culture System and the Role of EGFR Inhibition
Int. J. Mol. Sci. 2017, 18(8), 1655; https://doi.org/10.3390/ijms18081655
Received: 29 June 2017 / Revised: 21 July 2017 / Accepted: 25 July 2017 / Published: 29 July 2017
Cited by 3 | PDF Full-text (3228 KB) | HTML Full-text | XML Full-text
Abstract
Although bone metastases represent a major challenge in the natural history of breast cancer (BC), the complex interactions involved have hindered the development of robust in vitro models. The aim of this work is the development of a preclinical model of cancer and [...] Read more.
Although bone metastases represent a major challenge in the natural history of breast cancer (BC), the complex interactions involved have hindered the development of robust in vitro models. The aim of this work is the development of a preclinical model of cancer and bone stromal cells to mimic the bone microenvironment. We studied the effects on osteoclastogenesis of BC cells and Mesenchymal stem cells (MSC) cultured alone or in combination. We also analyzed: (a) whether the blockade of the Epithelial Growth Factor Receptor (EGFR) pathway modified their influence on monocytes towards differentiation, and (b) the efficacy of bone-targeted therapy on osteoclasts. We evaluated the osteoclastogenesis modulation of human peripheral blood monocytes (PBMC) indirectly induced by the conditioned medium (CM) of the human BC cell line SCP2, cultured singly or with MSC. Osteoclastogenesis was evaluated by TRAP analysis. The effect of the EGFR blockade was assessed by treating the cells with gefitinib, and analyzed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and Western Blot (WB). We observed that SCP2 co-cultured with MSC increased the differentiation of PBMC. This effect was underpinned upon pre-treatment of the co-culture with gefitinib. Co-culture of SCP2 with MSC increased the expression of both the bone-related marker Receptor Activator of Nuclear Factor κB (RANK) and EGFR in BC cells. These upregulations were not affected by the EGFR blockade. The effects of the CM obtained by the cells treated with gefitinib in combination with the treatment of the preosteoclasts with the bone-targeted agents and everolimus enhanced the inhibition of the osteoclastogenesis. Finally, we developed a fully human co-culture system of BC cells and bone progenitor cells. We observed that the interaction of MSC with cancer cells induced in the latter molecular changes and a higher power of inducing osteoclastogenesis. We found that blocking EGFR signaling could be an efficacious strategy for breaking the interactions between cancer and bone cells in order to inhibit bone metastasis. Full article
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Open AccessArticle
Clinical Role of ASCT2 (SLC1A5) in KRAS-Mutated Colorectal Cancer
Int. J. Mol. Sci. 2017, 18(8), 1632; https://doi.org/10.3390/ijms18081632
Received: 29 June 2017 / Revised: 24 July 2017 / Accepted: 24 July 2017 / Published: 27 July 2017
Cited by 8 | PDF Full-text (2817 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Mutation in the KRAS gene induces prominent metabolic changes. We have recently reported that KRAS mutations in colorectal cancer (CRC) cause alterations in amino acid metabolism. However, it remains to be investigated which amino acid transporter can be regulated by mutated KRAS in [...] Read more.
Mutation in the KRAS gene induces prominent metabolic changes. We have recently reported that KRAS mutations in colorectal cancer (CRC) cause alterations in amino acid metabolism. However, it remains to be investigated which amino acid transporter can be regulated by mutated KRAS in CRC. Here, we performed a screening of amino acid transporters using quantitative reverse-transcription polymerase chain reaction (RT-PCR) and then identified that ASCT2 (SLC1A5) was up-regulated through KRAS signaling. Next, immunohistochemical analysis of 93 primary CRC specimens revealed that there was a significant correlation between KRAS mutational status and ASCT2 expression. In addition, the expression level of ASCT2 was significantly associated with tumor depth and vascular invasion in KRAS-mutant CRC. Notably, significant growth suppression and elevated apoptosis were observed in KRAS-mutant CRC cells upon SLC1A5-knockdown. ASCT2 is generally known to be a glutamine transporter. Interestingly, SLC1A5-knockdown exhibited a more suppressive effect on cell growth than glutamine depletion. Furthermore, SLC1A5-knockdown also resulted in the suppression of cell migration. These results indicated that ASCT2 (SLC1A5) could be a novel therapeutic target against KRAS-mutant CRC. Full article
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Open AccessArticle
PGK1 Drives Hepatocellular Carcinoma Metastasis by Enhancing Metabolic Process
Int. J. Mol. Sci. 2017, 18(8), 1630; https://doi.org/10.3390/ijms18081630
Received: 16 May 2017 / Revised: 12 July 2017 / Accepted: 22 July 2017 / Published: 27 July 2017
Cited by 7 | PDF Full-text (5589 KB) | HTML Full-text | XML Full-text
Abstract
During the proliferation and metastasis, the tumor cells prefer glycolysis (Warburg effect), but its exact mechanism remains largely unknown. In this study, we demonstrated that phosphoglycerate kinase 1 (PGK1) is an important enzyme in the pathway of metabolic glycolysis. We observed a significant [...] Read more.
During the proliferation and metastasis, the tumor cells prefer glycolysis (Warburg effect), but its exact mechanism remains largely unknown. In this study, we demonstrated that phosphoglycerate kinase 1 (PGK1) is an important enzyme in the pathway of metabolic glycolysis. We observed a significant overexpression of PGK1 in hepatocellular carcinoma tissues, and a correlation between PGK1 expression and poor survival of hepatocellular carcinoma patients. Also, the depletion of PGK1 dramatically reduced cancer cell proliferation and metastasis, indicating an oncogenic role of PGK1 in liver cancer progression. Further experiments showed that PGK1 played an important role in MYC-induced metabolic reprogramming, which led to an enhanced Warburg effect. Our results revealed a new effect of PGK1, which can provide a new treatment strategy for hepatocellular carcinoma, as PGK1 is used to indicate the prognosis of hepatocellular carcinoma (HCC). Full article
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Open AccessArticle
Tanshinone IIA Inhibits Epithelial-Mesenchymal Transition in Bladder Cancer Cells via Modulation of STAT3-CCL2 Signaling
Int. J. Mol. Sci. 2017, 18(8), 1616; https://doi.org/10.3390/ijms18081616
Received: 29 June 2017 / Revised: 20 July 2017 / Accepted: 21 July 2017 / Published: 25 July 2017
Cited by 7 | PDF Full-text (2898 KB) | HTML Full-text | XML Full-text
Abstract
Tanshinone IIA (Tan-IIA) is an extract from the widely used traditional Chinese medicine (TCM) Danshen (Salvia miltiorrhiza), and has been found to attenuate the proliferation of bladder cancer (BCa) cells (The IC50 were: 5637, 2.6 μg/mL; BFTC, 2 μg/mL; T24, [...] Read more.
Tanshinone IIA (Tan-IIA) is an extract from the widely used traditional Chinese medicine (TCM) Danshen (Salvia miltiorrhiza), and has been found to attenuate the proliferation of bladder cancer (BCa) cells (The IC50 were: 5637, 2.6 μg/mL; BFTC, 2 μg/mL; T24, 2.7 μg/mL, respectively.). However, the mechanism of the effect of Tan-IIA on migration inhibition of BCa cells remains unclear. This study investigates the anti-metastatic effect of Tan-IIA in human BCa cells and clarifies its molecular mechanism. Three human BCa cell lines, 5637, BFTC and T24, were used for subsequent experiments. Cell migration and invasion were evaluated by transwell assays. Real-time RT-PCR and western blotting were performed to detect epithelial-mesenchymal transition (EMT)-related gene expression. The enzymatic activity of matrix metalloproteinases (MMP) was evaluated by zymography assay. Tan-IIA inhibited the migration and invasion of human BCa cells. Tan-IIA suppressed both the protein expression and enzymatic activity of MMP-9/-2 in human BCa cells. Tan-IIA up-regulated the epithelial marker E-cadherin and down-regulated mesenchymal markers such as N-cadherin and Vimentin, along with transcription regulators such as Snail and Slug in BCa cells in a time- and dose-dependent manner. Mechanism dissection revealed that Tan-IIA-inhibited BCa cell invasion could function via suppressed chemokine (C-C motif) ligand 2 (CCL2) expression, which could be reversed by the addition of CCL2 recombinant protein. Furthermore, Tan-IIA could inhibit the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) (Tyr705), which cannot be restored by the CCL2 recombinant protein addition. These data implicated that Tan-IIA might suppress EMT on BCa cells through STAT3-CCL2 signaling inhibition. Tan-IIA inhibits EMT of BCa cells via modulation of STAT3-CCL2 signaling. Our findings suggest that Tan-IIA can serve as a potential anti-metastatic agent in BCa therapy. Full article
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Open AccessArticle
Sulfiredoxin May Promote Cervical Cancer Metastasis via Wnt/β-Catenin Signaling Pathway
Int. J. Mol. Sci. 2017, 18(5), 917; https://doi.org/10.3390/ijms18050917
Received: 19 March 2017 / Revised: 17 April 2017 / Accepted: 22 April 2017 / Published: 27 April 2017
Cited by 11 | PDF Full-text (6896 KB) | HTML Full-text | XML Full-text
Abstract
The abnormal elevation of sulfiredoxin (Srx/SRXN1)—an antioxidant enzyme whose main function is to protect against oxidative stress—has been shown to be closely correlated with the progression of several types of cancer, including human cervical cancer. However, the molecular mechanism by which Srx promotes [...] Read more.
The abnormal elevation of sulfiredoxin (Srx/SRXN1)—an antioxidant enzyme whose main function is to protect against oxidative stress—has been shown to be closely correlated with the progression of several types of cancer, including human cervical cancer. However, the molecular mechanism by which Srx promotes tumor progression, especially cancer metastasis in cervical cancer, has not been elucidated. Here, we show that Srx expression gradually increases during the progression of human cervical cancer and its expression level is closely correlated with lymph node metastasis. Our study also reveals a significant positive correlation between the expression of Srx and β-catenin in cervical cancer tissues. Loss-of-function studies demonstrate that Srx knockdown using a lentiviral vector-mediated specific shRNA decreases the migration and invasion capacity in HeLa (human papilloma virus 18 type cervical cancer cell line) and SiHa SiHa (cervical squamous cancer cell line). Notably, the exact opposite effects were observed in gain-of-function experiments in C-33A cells. Mechanistically, downregulation or upregulation of Srx leads to an altered expression of proteins associated with the Wnt/β-catenin signaling pathway. Furthermore, blockage of the Wnt/β-catenin signaling pathway contributed to attenuated Srx expression and resulted in significant inhibition of cell migration and invasion in cervical cancer cell lines. Combined, Srx might be an oncoprotein in cervical cancer, playing critical roles in activating the Wnt/β-catenin signaling pathway; it may therefore be a therapeutic target for cervical cancer. Full article
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Open AccessArticle
Metformin Inhibits TGF-β1-Induced Epithelial-to-Mesenchymal Transition via PKM2 Relative-mTOR/p70s6k Signaling Pathway in Cervical Carcinoma Cells
Int. J. Mol. Sci. 2016, 17(12), 2000; https://doi.org/10.3390/ijms17122000
Received: 10 September 2016 / Revised: 19 November 2016 / Accepted: 22 November 2016 / Published: 30 November 2016
Cited by 21 | PDF Full-text (11366 KB) | HTML Full-text | XML Full-text
Abstract
Background: Epithelial-to-mesenchymal transition (EMT) plays a prominent role in tumorigenesis. Metformin exerts antitumorigenic effects in various cancers. This study investigated the mechanisms of metformin in TGF-β1-induced Epithelial-to-mesenchymal transition (EMT) in cervical carcinoma cells. Methods: cells were cultured with 10 ng/mL TGF-β1 to induce [...] Read more.
Background: Epithelial-to-mesenchymal transition (EMT) plays a prominent role in tumorigenesis. Metformin exerts antitumorigenic effects in various cancers. This study investigated the mechanisms of metformin in TGF-β1-induced Epithelial-to-mesenchymal transition (EMT) in cervical carcinoma cells. Methods: cells were cultured with 10 ng/mL TGF-β1 to induce EMT and treated with or without metformin. Cell viability was evaluated by CCK-8 (Cell Counting Kit 8, CCK-8) assay; apoptosis were analyzed by flow cytometry; cell migration was evaluated by wound-healing assay. Western blotting was performed to detect E-cadherin, vimentin, signal transducer and activator of transcription 3 (STAT3), snail family transcriptional repressor 2 (SNAIL2), phosphorylation of p70s6k (p-p70s6k) and -Pyruvate kinase M2 (PKM2) Results: TGF-β1 promoted proliferation and migration, and it attenuated apoptosis compared with cells treated with metformin with or without TGF-β1 in cervical carcinoma cells. Moreover, metformin partially abolished TGF-β1-induced EMT cell proliferation and reversed TGF-β1-induced EMT. In addition, the anti-EMT effects of metformin could be partially in accord with rapamycin, a specific mTOR inhibitor. Metformin decreased the p-p70s6k expression and the blockade of mTOR/p70s6k signaling decreased PKM2 expression. Conclusion: Metformin abolishes TGF-β1-induced EMT in cervical carcinoma cells by inhibiting mTOR/p70s6k signaling to down-regulate PKM2 expression. Our study provides a novel mechanistic insight into the anti-tumor effects of metformin. Full article
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Review

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Open AccessReview
Arachidonic Acid Metabolite as a Novel Therapeutic Target in Breast Cancer Metastasis
Int. J. Mol. Sci. 2017, 18(12), 2661; https://doi.org/10.3390/ijms18122661
Received: 1 November 2017 / Revised: 2 December 2017 / Accepted: 6 December 2017 / Published: 8 December 2017
Cited by 7 | PDF Full-text (1206 KB) | HTML Full-text | XML Full-text
Abstract
Metastatic breast cancer (BC) (also referred to as stage IV) spreads beyond the breast to the bones, lungs, liver, or brain and is a major contributor to the deaths of cancer patients. Interestingly, metastasis is a result of stroma-coordinated hallmarks such as invasion [...] Read more.
Metastatic breast cancer (BC) (also referred to as stage IV) spreads beyond the breast to the bones, lungs, liver, or brain and is a major contributor to the deaths of cancer patients. Interestingly, metastasis is a result of stroma-coordinated hallmarks such as invasion and migration of the tumor cells from the primary niche, regrowth of the invading tumor cells in the distant organs, proliferation, vascularization, and immune suppression. Targeted therapies, when used as monotherapies or combination therapies, have shown limited success in decreasing the established metastatic growth and improving survival. Thus, novel therapeutic targets are warranted to improve the metastasis outcomes. We have been actively investigating the cytochrome P450 4 (CYP4) family of enzymes that can biosynthesize 20-hydroxyeicosatetraenoic acid (20-HETE), an important signaling eicosanoid involved in the regulation of vascular tone and angiogenesis. We have shown that 20-HETE can activate several intracellular protein kinases, pro-inflammatory mediators, and chemokines in cancer. This review article is focused on understanding the role of the arachidonic acid metabolic pathway in BC metastasis with an emphasis on 20-HETE as a novel therapeutic target to decrease BC metastasis. We have discussed all the significant investigational mechanisms and put forward studies showing how 20-HETE can promote angiogenesis and metastasis, and how its inhibition could affect the metastatic niches. Potential adjuvant therapies targeting the tumor microenvironment showing anti-tumor properties against BC and its lung metastasis are discussed at the end. This review will highlight the importance of exploring tumor-inherent and stromal-inherent metabolic pathways in the development of novel therapeutics for treating BC metastasis. Full article
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Open AccessReview
Collateral Damage Intended—Cancer-Associated Fibroblasts and Vasculature Are Potential Targets in Cancer Therapy
Int. J. Mol. Sci. 2017, 18(11), 2355; https://doi.org/10.3390/ijms18112355
Received: 28 September 2017 / Revised: 25 October 2017 / Accepted: 2 November 2017 / Published: 7 November 2017
Cited by 12 | PDF Full-text (2917 KB) | HTML Full-text | XML Full-text
Abstract
After oncogenic transformation, tumor cells rewire their metabolism to obtain sufficient energy and biochemical building blocks for cell proliferation, even under hypoxic conditions. Glucose and glutamine become their major limiting nutritional demands. Instead of being autonomous, tumor cells change their immediate environment not [...] Read more.
After oncogenic transformation, tumor cells rewire their metabolism to obtain sufficient energy and biochemical building blocks for cell proliferation, even under hypoxic conditions. Glucose and glutamine become their major limiting nutritional demands. Instead of being autonomous, tumor cells change their immediate environment not only by their metabolites but also by mediators, such as juxtacrine cell contacts, chemokines and other cytokines. Thus, the tumor cells shape their microenvironment as well as induce resident cells, such as fibroblasts and endothelial cells (ECs), to support them. Fibroblasts differentiate into cancer-associated fibroblasts (CAFs), which produce a qualitatively and quantitatively different extracellular matrix (ECM). By their contractile power, they exert tensile forces onto this ECM, leading to increased intratumoral pressure. Moreover, along with enhanced cross-linkage of the ECM components, CAFs thus stiffen the ECM. Attracted by tumor cell- and CAF-secreted vascular endothelial growth factor (VEGF), ECs sprout from pre-existing blood vessels during tumor-induced angiogenesis. Tumor vessels are distinct from EC-lined vessels, because tumor cells integrate into the endothelium or even mimic and replace it in vasculogenic mimicry (VM) vessels. Not only the VM vessels but also the characteristically malformed EC-lined tumor vessels are typical for tumor tissue and may represent promising targets in cancer therapy. Full article
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Open AccessReview
Roles of Long Noncoding RNAs in Recurrence and Metastasis of Radiotherapy-Resistant Cancer Stem Cells
Int. J. Mol. Sci. 2017, 18(9), 1903; https://doi.org/10.3390/ijms18091903
Received: 13 July 2017 / Revised: 29 August 2017 / Accepted: 30 August 2017 / Published: 5 September 2017
Cited by 17 | PDF Full-text (1585 KB) | HTML Full-text | XML Full-text
Abstract
Radiotherapy is a well-established therapeutic regimen applied to treat at least half of all cancer patients worldwide. Radioresistance of cancers or failure to treat certain tumor types with radiation is associated with enhanced local invasion, metastasis and poor prognosis. Elucidation of the biological [...] Read more.
Radiotherapy is a well-established therapeutic regimen applied to treat at least half of all cancer patients worldwide. Radioresistance of cancers or failure to treat certain tumor types with radiation is associated with enhanced local invasion, metastasis and poor prognosis. Elucidation of the biological characteristics underlying radioresistance is therefore critical to ensure the development of effective strategies to resolve this issue, which remains an urgent medical problem. Cancer stem cells (CSCs) comprise a small population of tumor cells that constitute the origin of most cancer cell types. CSCs are virtually resistant to radiotherapy, and consequently contribute to recurrence and disease progression. Metastasis is an increasing problem in resistance to cancer radiotherapy and closely associated with the morbidity and mortality rates of several cancer types. Accumulating evidence has demonstrated that radiation induces epithelial–mesenchymal transition (EMT) accompanied by increased cancer recurrence, metastasis and CSC generation. CSCs are believed to serve as the basis of metastasis. Previous studies indicate that CSCs contribute to the generation of metastasis, either in a direct or indirect manner. Moreover, the heterogeneity of CSCs may be responsible for organ specificity and considerable complexity of metastases. Long noncoding RNAs (lncRNAs) are a class of noncoding molecules over 200 nucleotides in length involved in the initiation and progression of several cancer types. Recently, lncRNAs have attracted considerable attention as novel critical regulators of cancer progression and metastasis. In the current review, we have discussed lncRNA-mediated regulation of CSCs following radiotherapy, their association with tumor metastasis and significance in radioresistance of cancer. Full article
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