Search Results (262)

The development of novel platinum-based anticancer agents remains a critical objective in medicinal inorganic chemistry, particularly in light of resistance and toxicity limitations associated with cisplatin. In this study, the synthesis, structural characterization, quantum chemical analysis, and cytotoxic evaluation of four new acetylplatinum(II) complexes (cis-[Pt(COMe)₂(PASO₂)₂], cis-[Pt(COMe)₂(DAPTA)₂], trans-[Pt(COMe)Cl(DAPTA)₂], and trans-[Pt(COMe)Cl(PASO₂)]: 1–4, respectively) bearing cage phosphine ligands PASO₂ (2-thia-1,3,5-triaza-phosphaadamantane 2,2-dioxide) and DAPTA (3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane) are presented. The coordination geometries and NMR spectral features of the cis/trans isomers were elucidated through multinuclear NMR and DFT calculations at the B3LYP/6-311++G(d,p)/LanL2DZ level, with strong agreement between experimental and theoretical data. Quantum Theory of Atoms in Molecules (QTAIM) analysis was applied to investigate bonding interactions and assess the covalent character of Pt–ligand bonds. Cytotoxicity was evaluated against five human cancer cell lines. The PASO₂-containing complex in cis-configuration, 1, demonstrated superior activity against thyroid (8505C) and head and neck (A253) cancer cells, with potency surpassing that of cisplatin. The DAPTA complex 2 showed enhanced activity toward ovarian (A2780) cancer cells. These findings highlight the influence of ligand structure and isomerism on biological activity, supporting the rational design of phosphine-based Pt(II) anticancer drugs. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) is the seventh most prevalent cancer worldwide. Despite intensive treatments, the prognosis is unfavorable. Recently, immunotherapy has emerged as a novel therapeutic strategy, and several immune-checkpoint blockade blockers provide clinical benefits to patients. However, the response rates of these antibodies are limited, and there is a pressing need to increase the efficacy of immunotherapy for HNSCC patients. Epigenetic treatment is emerging as a promising combination approach able to change immune-related gene signatures in tumors and potentially increase the efficacy of immunotherapy. In this study, we sought to elucidate further immune-related gene signatures altered through epigenetic treatment and explored whether epigenetic drugs can increase the efficacy of anti PD-L1 treatment in HNSCC. Methods: At first, we treated six HNSCC cell lines with 5-azacytidine and romidepsin and analyzed gene expression patterns by microarray and TaqMan arrays analysis. We then explored the therapeutic efficacy of epigenetic treatment with an anti PD-L1 antibody in a syngeneic mouse model. Results: Our microarray analysis revealed the differential expression of immune-related genes in cell lines treated with epigenetic drugs, as compared to untreated controls. Most importantly, these array analyses showed a significant change in the transcription of some immune related-and biologically relevant genes, such as HLA-DRA, HMOX1, IFI6, IL12A, IRF7, NFKB2, RPL3L, STAT1, STAT3, CSF1, CSF2, FAS, OASL, and PD-L1, after epigenetic treatment. Furthermore, the combination of epigenetic treatment with an anti PD-L1 antibody significantly suppressed tumor growth in a syngeneic mouse model. In vivo tumors treated with epigenetic drugs expressed higher STAT1, STAT3, and PD-L1 compared to untreated tumors. Increased PD-L1 expression is postulated to increase the efficacy of anti PD-L1 treatment. Conclusions: Our results highlight the importance of a combinational strategy employing both epigenetic and immunotherapy in HNSCC. Full article

Background/Objectives: Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer, with limited responsiveness to immune checkpoint inhibitors (ICIs). Cancer vaccine therapy is a promising novel immunotherapeutic approach that stimulates tumor-specific T cells. Receptor tyrosine kinase-like orphan receptor 1 (ROR1), which is overexpressed in malignant tumors but minimally expressed in normal tissues, presents a promising target for immunotherapy. This study aimed to evaluate ROR1 as a target for helper T lymphocyte (HTL)-based peptide vaccine immunotherapy in HNSCC. Methods: ROR1 expression in HNSCC tissues was assessed by immunohistochemistry. A novel ROR1-derived epitope (ROR1_403–417) was identified and used to generate ROR1-reactive HTLs. Functional assays measuring IFN-γ and granzyme B secretion, as well as direct cytotoxicity, were performed. The effects of ICIs on HTL activity were also examined. The presence of ROR1-reactive T cells in the peripheral blood of patients with HNSCC was evaluated. Results: ROR1 positivity rates in HNSCC tissues were significantly higher (80.0%) than those in healthy controls (16.7%), and high ROR1 expression correlated with advanced clinical stages. HTL lines recognized the ROR1_403–417 peptide in a human leukocyte antigen (HLA)-DR-restricted manner, secreted effector cytokines, and exhibited direct cytotoxicity against ROR1+ tumor cells. Dual PD-L1/PD-L2 blockade further enhanced HTL responses. ROR1-reactive T cells were detected in the peripheral blood of patients with HNSCC. Conclusions: ROR1 represents a promising target for immunotherapy in HNSCC. The ROR1_403–417 peptide can elicit ROR1-reactive HTLs that exhibit antitumor responses against HNSCC cell lines, which can be enhanced by ICIs. These findings support the potential of ROR1-targeted peptide vaccine therapy for HNSCC. Full article

Head and neck squamous cell carcinoma (HNSCC) remains challenging to treat despite multimodal therapeutic approaches. Cisplatin treatment is effective and cost-efficient, although chemoresistance and disease recurrence limit its efficacy. Understanding the mechanisms of cisplatin resistance and the identification of compounds to target resistant tumor cells are critical for improving patient outcomes. We have demonstrated that cisplatin-induced senescent HN30 HNSCC cells can be eliminated by ABT-263 (navitoclax), a BCL-2/BCL-X_L inhibitor that has senolytic properties. Here, we report the development of a cisplatin-resistant cell line (HN30R) for the testing of ABT-263 and the PROTAC BET degraders ARV-825 and ARV-771. ABT-263 was ineffective in sensitizing HN30R cells to cisplatin, largely due to a lack of senescence induction. However, the BET degraders in combination with cisplatin promoted apoptotic cell death in both HN30 and HN30R cells. The effectiveness of ARV-825 did not appear to depend on the cells entering into senescence, indicating that it was not acting as a conventional senolytic. ARV-825 treatment downregulated BRD4 and its downstream targets, c-Myc and Survivin, as well as decreased the expression of RAD51, a DNA repair marker. These results suggest that the BET degraders ARV-825 and ARV-771 may be effective in improving the response of chemoresistant head and neck cancer to cisplatin treatment. Full article

Background: Cancer stem cells (CSCs) are a subpopulation of cancer cells known for their self-renewal capacity, tumorigenicity, and resistance to treatment. Toll-like receptor 3 (TLR3) plays a complex role in cancer, exhibiting both pro-apoptotic and pro-tumorigenic effects. This study investigates the pro-tumorigenic role of TLR3, specifically its impact on CSCs in head and neck cancer. Methods: We have investigated Detroit 562, FaDu and SQ20B cell lines, the latter being stably transfected with a plasmid containing inducible shRNA for TLR3, by cultivating them to form tumor spheres in order to study CSCs. Results: Our findings demonstrate that TLR3 activation promotes stemness in head and neck cancer cell lines. This is evidenced by increased tumor sphere formation, promotion of epithelial-to-mesenchymal transition (EMT), upregulated stemness gene expression, and elevated aldehyde dehydrogenase (ALDH) activity. Conditional TLR3 knockdown abolished tumor sphere formation, confirming its important role. Furthermore, TLR3 activation triggers the secretion of damage-associated molecular patterns (DAMPs) into the tumor microenvironment, leading to increased cancer cell migration. This was inhibited by DAMP inhibitors. In patient tissue samples, we observed co-localization of TLR3 with stemness markers CD133 and ALDH1, as well as with heat shock protein 70 (HSP70) and receptor for advanced glycation end products (RAGE). We then explored potential CSC-targeted therapies, initially combining the apoptosis inducer poly (I:C) with DAMP inhibitors and γ-irradiation. While this combination proved effective in adherent cells, it failed to eliminate tumor spheres. Nevertheless, we discovered that proton radiotherapy, particularly when combined with aspirin (HMGB1 inhibitor) and poly (I:C), effectively eliminates CSCs. Conclusions: This novel combination holds promise for the development of new therapeutic strategies for head and neck cancers, particularly given the promising results of proton therapy in treating this disease. Full article

From a previously performed proteomics screen, GPP130, or Golgi phosphoprotein of 130 kDa, was identified as a potential substrate of the proprotein convertase 7 (PC7; PCSK7). GPP130 is a type-II transmembrane protein with a luminal domain containing endosomal and Golgi-retrieval determinants, enabling a unique trafficking route. Most of the previous work on GPP130 relates to its binding and retrograde trafficking of the Shiga toxin. However, its cellular biology and its biochemical characterization remain understudied. Recently, GPP130 was reported to be implicated in cell cycle progression and cell proliferation in head and neck cancer cells. This led us to analyze the cBioPortal for Cancer Genomics, revealing that the GPP130/GOLIM4 gene is amplified in many cancers, including lung, ovarian, and cervical. This observation led us to use the A549 lung cancer cell line to investigate the growth-regulating roles of endogenous and overexpressed GPP130 and to analyze the impact of its cleavage/shedding by PC7 and/or Furin on cellular growth. Our cell-based assays suggest that GPP130 is a novel pro-protein convertase substrate that increases cell proliferation in A549, SKOV3, and HeLa cells, and that the latter activity is enhanced following its cleavage by PC7 and/or Furin into a membrane-bound N-terminal product and secreted C-terminal fragments. This novel work sheds light on the cell biology of the poorly characterized GPP130, its proliferative activity, and modulation upon its shedding by PC7 and Furin in lung cancer progression. Full article

Background/Objectives: Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy of the oral cavity and is frequently diagnosed at an advanced stage, resulting in poor prognosis and limited treatment options. Identifying reliable biomarkers that can predict tumor progression and serve as therapeutic targets remains an urgent clinical need. Methods: To identify key molecular drivers in OSCC, we performed an integrative bioinformatics analysis of five OSCC-related microarray datasets from the Gene Expression Omnibus (GEO). Differentially expressed genes (DEGs) were identified and subjected to functional enrichment, protein–protein interaction (PPI) network construction, and hub gene ranking using Cytoscape. Candidate genes were further validated using TCGA, UALCAN, and the Human Protein Atlas. In vitro functional assays were performed to evaluate the effect of TK1 knockdown on cell migration. Results: A total of 138 common DEGs were identified across datasets. GO enrichment revealed that these genes were associated with cell proliferation, extracellular matrix organization, and metastasis-related processes. Thymidine kinase 1 (TK1) was identified as a key hub gene and found to be consistently overexpressed in OSCC tissues. Kaplan–Meier analysis showed that high TK1 expression correlated with poor overall survival in head and neck cancer. TK1 knockdown in OSCC cell lines significantly impaired cell migration and wound-healing ability. Conclusions: Our findings suggest that TK1 plays an active role in promoting OSCC progression and may serve as a prognostic biomarker and potential therapeutic target for metastatic OSCC. Full article

Disease progression and treatment resistance in colorectal and other cancers are driven by a subset of cells within the tumor that have stem-cell-like properties and long-term tumorigenic potential. These stem-cell-like cells express the leucine-rich G repeat-containing protein-coupled receptor 5 (LGR5) and have characteristics similar to tissue-resident stem cells in normal adult tissues such as the colon. Organoid models of murine and human colorectal and other cancers contain LGR5-expressing (LGR5+) stem-cell-like cells and can be used to investigate the underlying mechanisms of cancer development, progression, therapy vulnerability, and resistance. A large biobank of organoids derived from colorectal cancer or adjacent normal tissue was developed. We performed a large-scale unbiased functional screen to identify bispecific antibodies (BsAbs) that preferentially inhibit the growth of colon tumor-derived, as compared to normal tissue-derived, organoids. We identified the most potent BsAb in the screen as petosemtamab, a Biclonics^® BsAb targeting both LGR5 and the epidermal growth factor receptor (EGFR). Petosemtamab employs three distinct mechanisms of action: EGFR ligand blocking, EGFR receptor internalization and degradation in LGR5+ cells, and Fc-mediated activation of the innate immune system by antibody-dependent cellular phagocytosis (ADCP) and enhanced antibody-dependent cellular cytotoxicity (ADCC) (see graphical abstract). Petosemtamab has demonstrated substantial clinical activity in recurrent/metastatic head and neck squamous cell carcinoma (r/m HNSCC). The safety profile is generally favorable, with low rates of skin and gastrointestinal toxicity. Phase 3 trials are ongoing in both first-line programmed death-ligand 1-positive (PD-L1+) and second/third-line r/m HNSCC. Full article

Chemotherapy is a common treatment method for cancer that is often associated with strong side effects. To reduce these, research on extracts from medicinal plants and their active ingredients has been conducted. Although sea buckthorn (Hippophae rhamnoides) is a well-established medicinal plant, little is known about the chemical components responsible for its putative anticancer activity. This study focuses on both chemical and medical analyses of methanolic sea buckthorn root extracts. Cell viability measurements were performed on head and neck cancer cell lines, as well as non-tumorigenic control cells. Microwave and classical extractions under reflux were used to prepare the methanolic extracts. LC/MS and NMR were used to determine the structures of the molecules contained within these extracts. The aqueous phase of one sea buckthorn root extract reduced the viability of cancer cells, whereas the viability of non-tumorigenic control cells remained unaltered. The cell cycle phases of cancer cells treated with the extract shifted in comparison to control treatment. After 24 h, the number of cells in proliferative phases had increased. Two fractions of the extract that evoked alterations were identified. After a 48 h treatment, one of the fractions showed a higher number of apoptotic cells than the control. LC/MS and NMR analyses were conducted to attempt to identify the active compounds. We propose that the bioactivity of this extract is caused by a mixture of 2′-hydroxyflavone isomers. Full article

Background: Chronic nicotine exposure drives head and neck cancer (HNC) progression, yet its molecular mechanisms remain underexplored. This study examines nicotine-induced transcriptomic changes and potential therapies via drug repurposing. Methods: HNC cell lines (OECM1, SAS, and CGHNC9) were exposed to an IC30 nicotine dose for three months to model chronic exposure in habitual smokers. Transcriptomic profiling of these sublines was integrated with TCGA-HNSC patient data. Differentially expressed genes (DEGs) underwent functional pathway enrichment analysis. Drug repurposing was conducted using gene–drug correlation analysis across GDSC, CTRP, and PRISM databases. Results: Transcriptomic analysis identified 1223 DEGs in nicotine-exposed HNC cells, and integration with TCGA-HNSC data defined a Nic-HNC gene set of 168 genes: 149 oncogenes and 19 tumor suppressors, with 36 oncogenes overexpressed in heavy smokers. Pathway analysis revealed the upregulation of oncogenic signaling, such as PI3K-AKT, alongside the suppression of immune regulation and metabolic reprogramming. Drug repurposing identified five compounds—AZD1332, JAK-8517, NU7441, BRD-K30748066, and neopeltolide—with the first two exhibiting the strongest inverse correlations with nicotine-induced oncogenes in heavy smokers, highlighting their potential as targeted therapies for tobacco-associated HNC. Conclusions: This study comprehensively characterizes nicotine-driven molecular dysregulation in HNC and proposes AZD1332 and JAK-8517 as promising therapeutic candidates through drug repurposing. These insights advance our understanding of nicotine’s oncogenic role and provide a foundation for translational research to develop targeted interventions for tobacco-associated HNC. Full article

Oral squamous cell carcinoma (OSCC) is one of the most common types of cancer in the head and neck region. In advanced stages of OSCC, chemotherapy is commonly used for treatment, despite some cancer cells having low sensitivity to anticancer drugs. We focused on RBM17/SPF45 as an essential drug-sensitizing factor in the context of malignant cells acquiring chemoresistance. Here, we demonstrate how RBM17 affects anticancer drug resistance in OSCC and we suggest the possible mechanism underlying its effects. After exposing oral cancer cell lines to fluorouracil (5-FU) and cisplatin, but not paclitaxel, the gene and protein expression of RBM17 increased. We found that siRNA-mediated RBM17-knockdown of the cell lines gained a significantly higher sensitivity to 5-FU, which was remarkably followed by a decrease in the expression of checkpoint kinase 1 (CHEK1) protein, whereas treatment with a CHEK1 inhibitor did not affect RBM17 protein expression in the oral cancer cell lines. These results indicate that RBM17 is a factor involved in the development of resistance to cytotoxic chemotherapy. We propose the underlying mechanism that RBM17 promotes CHEK1 protein expression in the ATM/ATR pathway, triggering the development of chemoresistance in cancer cells. Full article

Background/Objectives: HPV+ head and neck squamous cell carcinoma has been shown to have a unique genomic background, requiring researchers to study it as its own distinct type of cancer. HPV+ tumors have been shown to exhibit fewer genetic mutations in cancer drivers as opposed to their HPV− counterparts. In this paper, we explored how targeting post-transcriptional changes, specifically alternative splicing events, could serve as a potential mechanism to treat HPV+ cancer. Methods: Using indisulam, a drug that targets alternative splicing through the degradation of RBM39, we treated various HPV+ and HPV− cell lines and assessed tumor cell viability. We also tested indisulam in vivo to evaluate its effect on tumor volume. Additionally, we analyzed gene expression differences between indisulam-treated subjects and their non-treated counterparts. Results: Indisulam treatment led to a reduction in tumor cell viability in both HPV+ and HPV− cell lines. In vivo experiments showed a reduction in tumor volume following indisulam treatment. Gene expression analysis revealed that indisulam induces consistent differential gene expression changes and highly enriches interferon pathways in treated HPV+ cell lines. Conclusions: These findings suggest that targeting alternative splicing via indisulam may be a promising therapeutic approach for HPV+ cancers. Further research is required to establish indisulam as a viable anti-cancer treatment in clinical settings. Full article

Background: the treatment of squamous cell carcinomas of the oral cavity (OSCCs) is limited by the lack of reliable diagnostic/prognostic, and predictive markers, as well as by intrinsic tumor cell heterogeneity. 5-azacytidine (5-AZA) offers opportunities for cancer cell reprogramming to develop new target-specific treatments. The protein annexin A1 (ANXA1) is downregulated in head and neck squamous cell carcinoma (HNSCC), correlated with pathological differentiation grade. Objectives: this work aimed to further investigate the role of ANXA1 in OSCC progression based on 5-AZA activity. Methods: we used CAL27 and CAL33 cell lines, which differ in drug sensitivity and differentiation status. Results: CAL27 showed a higher expression of the stemness markers compared to CAL33 cells, but this positivity was lost after treatment with 5-AZA. This drug also decreased CAL27 cell motility, promoting a less aggressive phenotype. Moreover, 5-AZA increased ANXA1 expression only in CAL27. After siRNA-mediated downmodulation, we witnessed a significant rise in cell motility and the inversion of E-/N-cadherin expression, which was reverted again by 5-AZA. To investigate the role of exogenous ANXA1 derived from the tumor microenvironment, we treated CAL27 with Ac2-26, an ANXA1 mimetic peptide. Interestingly, we found that this peptide alone showed impacts similar to 5-AZA in reversing the aggressive phenotype. All these effects were not evidenced in CAL33 cells. Finally, to prove the loop of the exogenous protein, we detected increased expression of its receptors, formyl peptide receptors (FPRs), and their activation, leading to oncosuppressor effects. Conclusions: we propose that ANXA1 mediates the effects of 5-AZA only in poorly differentiated stemlike CAL27 cell lines. This suggests the relevance of ANXA1 as a diagnostic/prognostic biomarker in OSCCs, paving the way for personalized therapies to overcome treatment difficulties. Full article

Background: Head and neck cancer (HNC) evades immune responses by manipulating the tumor immune microenvironment (TIME). Tumor-bound Axl has been implicated in promoting an immunosuppressive TIME in HNC, though its precise role remains unclear. Understanding Axl’s contribution to immune evasion in HNC could lead to the identification of new therapeutic targets; therapies directed at these targets could be combined with and thereby enhance immunotherapies. Results: Using Axl knockout (Axl KO) cell lines derived from the immunologically “cold” MOC2 mouse model, we found that Axl loss delayed tumor growth in immunocompetent mice. This was accompanied by reduced immunosuppressive cells, including MDSCs, T_regs, B cells, and neutrophils, and increased infiltration of cytotoxic CD8 T cells and NK cells. To identify the immune population(s) responsible for these changes, Axl KO tumors were implanted in immune-deficient mice. Axl KO tumor growth in athymic nude mice (which lack T cells) was unchanged, whereas tumor growth in NCG mice (which lack NK cells) was rescued, suggesting that NK cells mediate the Axl KO tumor growth delay. Further, Axl loss enhanced NK cell cytotoxicity in vitro and in vivo, and NK cell depletion reversed delayed Axl KO tumor growth. Mechanistically, Axl KO tumors showed decreased expression of CD73 and CCL2, which inhibit NK cells, and increased expression of CCL5 and CXCL10, which promote NK cell recruitment and activation. Conclusions: These novel findings suggest that tumor-bound Axl fosters an immunosuppressive TIME by inhibiting NK cell recruitment and function, thereby promoting tumor growth. Targeting Axl may enhance NK cell-mediated tumor killing and improve immunotherapy efficacy in HNC. Full article

Head and neck cancer (HNC) is one of the most common types of cancer in the world, characterized by resistance to conventional therapies and an unfavorable prognosis due to the presence of tumor stem cells (TSCs). TSCs are cell subpopulations with high potential for invasion, migration, and metastasis, being responsible for the initiation and dissemination of cancer. This study aimed to evaluate the efficacy of treatments with cetuximab and paclitaxel, alone and in combination, in TSCs from oral cavity (SCC-28) and hypopharynx (FADU) cancer cell lines. In addition, the influence of the gene and protein expression of EGFR, NTRK2 (TRKB), KRAS, and HIF-1α on the response to treatments was investigated. TSCs were identified based on ALDH staining, and cell viability assays (MTS) indicated that both TSCs and non-TSCs showed resistance to cetuximab monotherapy, while paclitaxel, either alone or in combination with cetuximab, was more effective in reducing cell viability. Real-time PCR and Western blot analysis revealed increased expression of KRAS and HIF-1α in TSCs, suggesting their possible association with treatment resistance. The results of this study point to specific molecular factors that influence therapeutic responses in HNC, with an emphasis on the efficacy of drug combinations to overcome TSC resistance. The identification of these molecular mechanisms may provide guidelines for the development of more targeted and effective therapies against HNC, improving clinical management and patient prognoses. Full article