Search Results (247)

The tumor microenvironment plays an important role in tumor incidence, metastasis, and chemotherapy resistance. Novel therapeutic strategies targeting the tumor microenvironment have become a research focus in the field of biomedicine. In this study, we developed a smart small-molecule probe, TZ2, featuring pH/GSH dual-responsive characteristics. TZ2 exhibits a unique pH-dependent reaction mechanism: GSH is preferentially covalently modified with maleimide groups in acidic microenvironments (pH < 7), while specifically activating nucleophilic substitutions under alkaline conditions (pH > 7). It is worth noting that TZ2 effectively eliminates intracellular glutathione (GSH) in a time and concentration-dependent manner, demonstrating significant GSH depletion ability in various tumor cell lines. Pharmacodynamic studies have shown that TZ2 not only inhibits the cell cycle by regulating the expression of cell cycle-related proteins, but also effectively suppresses the cloning ability of cancer cells. Furthermore, TZ2 significantly increases the sensitivity of drug-resistant cancer cells to cisplatin. By integrating microenvironment modulation, real-time monitoring, and synergistic therapy, TZ2 provides a novel molecular tool and theoretical basis for tumor theranostics integration. Full article

The tumor microenvironment contains distinctive biomarkers, including acidic pH, elevated levels of reactive oxygen species (ROS), and hypoxia, necessitating the development of efficient biosensors for simplified cancer detection. This study presents an O₂-responsive hydrogel biosensor composed of [1,1′-biphenyl]-2,2′,4,4′,5,5′-hexaol (HDP) and polyvinyl alcohol (PVA) that exploits polyphenol-mediated interactions under N₂ and O₂ microenvironments. The oxidative susceptibility of the polyphenolic HDP moiety influences its distinct mechanical, physical, and electrochemical properties, allowing the differentiation between cancerous and normal cells. The in vitro assessments with cancer cell lines (HeLa and B16F10) and normal cell lines (CHO-K1) enabled distinctive electrical and mechanophysical outputs, as evidenced by enhanced mechanical compressive modulus and high conductivity, regulated by normoxic cellular states. In addition, the inherent ROS-scavenging capability of the HDP–PVA hydrogel sensor supports its potential application in hypoxia-related diseases, including cancer. Full article

Cellular and molecular characteristics of the tumor microenvironment are fundamental for the formation of niches. These structures include both cellular and matrix components and have been shown to protect and promote cancer formation and progression. The peculiarities of tumor niches have been suggested by many authors as targets with high therapeutic potential. This narrative review analyzes the chemical characteristics of the tumor microenvironment and describes experimental and clinical approaches to influence its contribution to cancer promotion and the spread of metastases. In particular, the possible chemical differences, like pH, oxygen levels, and cell composition, to be used for the design of drugs or the delivery of antiproliferative moieties for a more precise oncology approach, will be discussed. The literature proposes a vast number of molecules, but this review focuses on hypoxia-activated molecules, pH-sensitive nanocarriers, metal-based drugs, and gasotransmitters targeting selectively the tumor microenvironment as possible negative modulators of the contribution of niches to tumor promotion. The chemical peculiarities of the tumor niche are discussed for possible pharmacological developments. Full article

Immunotherapy has emerged as a transformative approach in gastrointestinal (GI) cancers, addressing historically poor survival rates in advanced-stage disease. Immune checkpoint inhibitors (ICIs) targeting the PD-1/PD-L1 axis demonstrate remarkable efficacy in colorectal cancer with deficient mismatch repair (dMMR) or high microsatellite instability (MSI-H), exemplified by trials like NICHE-2 achieving exceptional pathological response rates. However, significant limitations persist, including resistance in some dMMR/MSI-H tumors, minimal efficacy in proficient mismatch repair (pMMR) tumors, and low overall response rates across most GI malignancies due to tumor heterogeneity and immune evasion mechanisms. Predictive biomarkers such as tumor mutational burden (TMB) and PD-L1 expression are crucial for optimizing patient selection, while hypermutated pMMR tumors with POLE mutations represent emerging therapeutic opportunities. In pancreatic adenocarcinoma, where survival remains dismal, combination strategies with chemotherapy and novel approaches like cancer vaccines show promise but lack transformative breakthroughs. Esophagogastric cancers benefit from ICIs combined with chemotherapy, particularly in MSI-H and HER2-positive tumors, while hepatocellular carcinoma has achieved significant progress with combinations like atezolizumab–bevacizumab and durvalumab–tremelimumab surpassing traditional therapies. Biliary tract cancers show modest improvements with durvalumab–chemotherapy combinations. Despite these advances, immunotherapy faces substantial challenges including immune-related adverse events, acquired resistance through cancer immunoediting, and the need for biomarker-driven approaches to overcome tumor microenvironment barriers. This review discusses key clinical trials, therapeutic progress, and emerging modalities including CAR T-cell therapies and combination strategies, emphasizing the critical need to address resistance mechanisms and refine precision medicine approaches to fully realize immunotherapy’s potential in GI malignancies. Full article

Tumor cells often exhibit mitochondrial dysfunction and a pronounced glycolytic shift (the “Warburg effect”) that alters the tumor microenvironment. These metabolic changes, including mitochondrial DNA mutations and impaired oxidative phosphorylation, confer survival advantages and can reduce sensitivity to chemotherapeutics such as paclitaxel. In hypoxic environments, cancer cells upregulate glycolysis via HIF-1α, consequently lowering the extracellular pH through lactate secretion, which is associated with resistance to paclitaxel. Likewise, cancer-associated fibroblasts and immune cells undergo metabolic reprogramming in the tumor microenvironment. Glycolytic CAFs produce lactate and pyruvate that fuel tumor cells, reinforcing drug resistance, and tumor-driven polarization of macrophages toward an immunosuppressive M2 phenotype further impairs the anti-tumor response. Here, we review recent findings on how these metabolic adaptations attenuate paclitaxel efficacy and discuss strategies to overcome resistance. We highlight 15 key studies that reported cancer types, metabolic alterations, molecular targets, and outcomes related to paclitaxel response. Overall, the data suggest that targeting metabolic vulnerabilities, for example, by inhibiting glycolysis (HK2, PGAM1, and PDK) or modulating mitochondrial function, may restore paclitaxel sensitivity. Understanding metabolic crosstalk in the tumor microenvironment provides a basis for combined therapies that improve outcomes in paclitaxel-resistant cancers. Full article

Transient receptor potential classical or cation channels (TRPCs) are integral to tumor biology, particularly in maintaining Ca²⁺ homeostasis within cancer cells. TRPC5, a pH-sensitive member of this family, may act as a signaling molecule in the altered microenvironment of solid tumors, which are characterized by an inverted pH-gradient—with decreased extracellular and increased intracellular pH—that promotes tumor progression. This study addresses a gap in the field, as there is currently limited research on TRPC5, particularly regarding its potential role as a tumor marker. While TRPCs are known to be involved in cancer biology, the specific role of TRPC5 in solid tumors, including its potential role as a diagnostic marker, remains largely unexplored. This study is the first to examine TRPC5 expression profiles in common skin cancers, including basal cell carcinoma (BCC), squamous cell carcinoma (SCC), malignant melanoma (MM), and nevus cell nevi (NCN). Our findings reveal that the frequency of TRPC5 expression in BCC is significantly lower compared to SCC and epidermal portions of NCN and MM. These results suggest that TRPC5 could serve as an immunohistochemical marker to distinguish SCC from BCC. Additionally, this study lays the groundwork for future research into the role of TRPC5 in tumor progression and metastasis, especially since BCCs, which rarely metastasize, are predominantly negative for TRPC5. Full article

Pancreatic cancer cells exhibit a remarkable ability to tolerate nutrient deprivation, a phenomenon termed “austerity,” which enables their survival within the hypovascular tumor microenvironment. Conventional anticancer therapies frequently fail to effectively target these resilient neoplastic cells, posing a significant challenge to the therapeutic management of pancreatic cancer. Consequently, targeting austerity, the ability of cancer cells to tolerate nutrient starvation, represents a promising anti-austerity strategy for developing novel pancreatic cancer therapeutics. In this study, we investigated calliviminone A (CVM-A), a phloroglucinol–meroterpenoid isolated from Callistemon citrinus leaves, for its anti-austerity activity against PANC-1 human pancreatic cancer cells. Calliviminone A exhibited potent preferential cytotoxicity in nutrient-deprived medium (NDM) with a PC₅₀ of 0.57 µM, while showing minimal toxicity in nutrient-rich Dulbecco’s Modified Eagle’s medium (IC₅₀ = 45.2 µM), indicating a favorable therapeutic index. Real-time live-cell imaging revealed that CVM-A induced significant morphological changes, including cell shrinkage and membrane blebbing, leading to cell death within 24 h of NDM. Furthermore, under normal nutrient conditions in Dulbecco’s Modified Eagle’s Medium (DMEM), CVM-A significantly inhibited PANC-1 cell migration (up to 47% reduction at 20 µM) and colony formation (over 80% suppression at 25 µM), suggesting its antimetastatic potential. Western blot studies demonstrated that CVM-A downregulated key survival components of the PI3K/Akt/mTOR signaling pathway, completely inhibiting Akt and p-Akt at 2.5 µM in NDM, and suppressing insulin-induced Akt activation. These findings highlight CVM-A as a promising lead compound for developing novel anticancer therapies that target the adaptive survival mechanisms and metastatic potential of pancreatic cancer in nutrient-deprived microenvironments. Full article

Pediatric high-grade gliomas (pHGGs), particularly diffuse midline gliomas (DMGs), are among the most lethal brain tumors due to poor survival and resistance to therapies. DMGs possess a distinct genetic profile, primarily driven by hallmark mutations such as H3K27M, ACVR1, and PDGFRA mutations/amplifications and TP53 inactivation, all of which contribute to tumor biology and therapeutic resistance. Developing physiologically relevant preclinical models that replicate both tumor biology and the tumor microenvironment (TME) is critical for advancing effective treatments. This review highlights recent progress in in vitro, ex vivo, and in vivo models, including patient-derived brain organoids, genetically engineered mouse models (GEMMs), and region-specific midline organoids incorporating SHH, BMP, and FGF2/8/19 signaling to model pontine gliomas. Key genetic alterations can now be introduced using lipofectamine-mediated transfection, PiggyBac plasmid systems, and CRISPR-Cas9, allowing the precise study of tumor initiation, progression, and therapy resistance. These models enable the investigation of TME interactions, including immune responses, neuronal infiltration, and therapeutic vulnerabilities. Future advancements involve developing immune-competent organoids, integrating vascularized networks, and applying multi-omics platforms like single-cell RNA sequencing and spatial transcriptomics to dissect tumor heterogeneity and lineage-specific vulnerabilities. These innovative approaches aim to enhance drug screening, identify new therapeutic targets, and accelerate personalized treatments for pediatric gliomas. Full article

Stimuli-responsive silica nanoparticles have emerged as a promising platform for the targeted and controlled delivery of therapeutic agents in cancer therapy. These nanoparticles possess unique physicochemical properties that allow for the stimuli-triggered release of loaded cargos, such as drugs, enzymes, oligonucleotides, photosensitizers, and metals. The stimuli-responsive nature of these nanoparticles enables them to respond to specific internal and external signals within the tumor microenvironment, including pH, temperature, and redox potential, among others. This leads to the enhanced targeting of cancer cells and improved therapeutic efficacy while minimizing the off-target effects. This review highlights recent advances in the development and application of stimuli-responsive silica nanoparticles for the delivery of multiple active agents for cancer therapy. Overall, stimuli-responsive silica nanoparticles offer great potential for the development of more effective cancer therapies with improved selectivity and reduced side effects. Full article

Programmed death-ligand 1 (PD-L1) on tumor cells, including Hodgkin and Reed–Sternberg (HRS) cells in classical Hodgkin’s lymphoma (cHL), suppresses immune responses in the tumor immune microenvironment (TME). We analyzed PD-L1 expression in macrophages and HRS cells of 98 cHL cases and correlated the findings with clinicopathological features, overall survival (OS), and progression-free survival (PFS). Epstein–Barr virus (EBV) was detected by in situ hybridization for EBV-encoded RNA. Ten high-power fields were evaluated to count the total number of macrophages and PD-L1+ macrophages, and to calculate PD-L1 histoscore (H-score) in HRS cells. EBV-positive cHL was found in 22.5% of patients. The median H-score was 80 (range 0–300). Bulky disease was associated with a lower number of PD-L1+ macrophages, and extranodal disease with a higher number (p = 0.05). EBV-positive cHL showed a higher PD-L1 H-score in HRS cells and a greater number of PD-L1⁺ macrophages (p = 0.005); both of these features, along with the proportion of PD-L1⁺ macrophages, were associated with shorter PFS and OS (p < 0.001). High PD-L1 expression in HRS and macrophages may be linked to worse clinical outcomes. Full article

Colorectal cancer (CRC) is the third most common cancer in the world, with increasing incidence and mortality rates. Standard conventional treatments for CRC are surgery, chemotherapy, and radiotherapy. Recently, immunotherapy has been introduced as a promising alternative to CRC treatment that utilizes patients’ immune system to combat cancer cells. The beneficial effect of immune checkpoint inhibitors, specifically anti-PD-1/ PD-L1, has been ascribed to the abundance of DNA replication errors that result in the formation of neoantigens. Such neoantigens serve as distinct flags that amplify the immune response when checkpoint inhibitors (ICIs) are administered. DNA replication errors in CRC patients are expressed as two statuses: the first is the deficient mismatch repair (MSI-H/dMMR) with a higher overall immune response and survival rate than the second status of patients with proficient mismatch repair (MSS/pMMR). There is a limitation to using anti-PD-1/PD-L1 as it is only confined to MSI-H/dMMR, where there is an abundance of T-cell inhibitory ligands (PD-L1). This calls for investigating new therapeutic interventions to widen the scope of ICIs’ role in the treatment of CRC. Autophagy modulation provides a good example. Autophagy is a cellular process that plays a crucial role in maintaining cellular homeostasis and has been studied for its impact on tumor development, progression, and response to treatment. In this review, we aim to highlight autophagy as a potential determinant in tumor immune response and to study the impact of autophagy on the tumor immune microenvironment. Moreover, we aim to investigate the value of a combination of anti-PD-1/PD-L1 agents with autophagy modulators as an adjuvant therapeutic approach for CRC treatment. Full article

The tumor microenvironment (TME) has a major role in malignancy and its complex nature can mediate tumor survival, metastasis, immune evasion, and drug resistance. Thus, reprogramming or regulating the immunosuppressive TME has a significant contribution to make in cancer therapy. Targeting TME with nanocarriers (NCs) has been widely used to directly deliver anticancer drugs to control TME, which has revealed auspicious outcomes. TME can be reprogrammed by using a range of NCs to regulate immunosuppressive factors and activate immunostimulatory cells. Moreover, TME can be ameliorated via regulating the redox environment, oxygen content, and pH value of the tumor site. NCs have the capacity to provide site-specific delivery of therapeutic agents, controlled release, enhanced solubility and stability, decreased toxicities, and enhanced pharmacokinetics as well as biodistribution. Numerous NCs have demonstrated their potential by inducing distinct anticancer mechanisms by delivering a range of anticancer drugs in various preclinical studies, including metal NCs, liposomal NCs, solid lipid NCs, micelles, nanoemulsions, polymer-based NCs, dendrimers, nanoclays, nanocrystals, and many more. Some of them have already received US Food and Drug Administration approval, and some have entered different clinical phases. However, there are several challenges in NC-mediated TME targeting, including scale-up of NC-based cancer therapy, rapid clearance of NCs by the mononuclear phagocyte system, and TME heterogeneity. In order to harness the full potential of NCs in tumor treatment, there are several factors that need to be carefully studied, including optimization of drug loading into NCs, NC-associated immunogenicity, and biocompatibility for the successful translation of NC-based anticancer therapies into clinical practice. In this review, a range of NCs and their applications in drug delivery to remodel TME for cancer therapy are extensively discussed. Moreover, findings from numerous preclinical and clinical studies with these NCs are also highlighted. Full article

Background/Objectives: Nanocarrier particle design for treating chronic pulmonary diseases presents several challenges, including anatomical and physiological barriers. Drug-repurposing technology using monodispersed spherical silica is one of the innovative ways to deliver drugs. In the present study, the anticancer potential of combinational cisplatin/ribavirin was explored for targeted lung cancer therapeutics. Methods: Monodispersed spherical silica (80 nm) capable of diffusing into the tracheal mucus region was chosen and doped with 10 wt% superparamagnetic iron oxide nanoparticles (SPIONs). Subsequently, it was wrapped with chitosan (Chi, 0.6 wt/vol%), functionalized with 5% wt/wt cisplatin (Cp)/ribavarin (Rib) and angiotensin-converting enzyme 2 (ACE-2) (1.0 μL/mL). Formulations are based on monodispersed spherical silica or halloysite and are termed as (S/MSSiO₂/Chi/Cp/Rib) or (S/Hal/Chi/Cp/Rib), respectively. Results: X-ray diffraction (XRD) and diffuse reflectance UV-visible spectroscopy (DRS-UV-vis) analysis of S/MSSiO₂/Chi/Cp/Rib confirmed the presence of SPION nanoclusters on the silica surface (45% coverage). The wrapping of chitosan on the silica was confirmed with a Fourier transformed infrared (FTIR) stretching band at 670 cm⁻¹ and ascribed to the amide group of the polymer. The surface charge by zetasizer and saturation magnetization by vibrating sample magnetometer (VSM) were found to be −15.3 mV and 8.4 emu/g. The dialysis membrane technique was used to study the Cp and Rib release between the tumor microenvironment and normal pH ranges from 5.5 to 7.4. S/MSSiO₂/Chi formulation demonstrated pH-responsive Cp and Rib at acidic pH (5.6) and normal pH (7.4). Cp and Rib showed release of ~27% and ~17% at pH 5.6, which decreases to ~14% and ~3.2% at pH 7.4, respectively. To assess the compatibility and cytotoxic effect of our nanocomposites, the cell viability assay (MTT) was conducted on cancer lung cells A549 and normal HEK293 cells. Conclusions: The study shows that the designed nanoformulations with multifunctional capabilities are able to diffuse into the lung cells bound with dual drugs and the ACE-2 receptor. Full article

Understanding cancer etiology requires replicating the tumor microenvironment (TME), which significantly differs from standard in vitro cultures due to nutrient limitations, acidic pH, and oxidative stress. To address this, a microfluidic bioreactor (µBR) with an expanded culture surface was designed to optimize exosome enrichment and glioblastoma cell behavior. Using response surface methodology (RSM), key parameters—including medium exchange volume and interval time—were optimized, leading to about a six-fold increase in exosome concentration without artificial inducers. Characterization techniques (SEM, AFM, DLS, RT-qPCR, and ELISA) confirmed significant alterations in exosome profiles, cancer stemness, and epithelial-mesenchymal transition (EMT)-related markers. Notably, EMT was induced in the µBR system, with a six-fold increase in HIF-1α protein despite normoxic conditions, suggesting activation of compensatory signaling pathways. Molecular analysis showed upregulation of SOX2, OCT4, and Notch1, with SOX2 protein reaching 28 ng/mL, while it was undetectable in traditional culture. Notch1 concentration tripled in the µBR system, correlating with enhanced stemness and phenotypic heterogeneity. Immunofluorescent microscopy confirmed nuclear SOX2 accumulation and co-expression of SOX2 and HIF-1α in dedifferentiated CSC-like cells, demonstrating tumor heterogeneity. These findings highlight the µBR’s ability to enhance stemness and mimic glioblastoma’s aggressive phenotype, establishing it as a valuable platform for tumor modeling and therapeutic development. Full article

Prostate cancer (PCa) is the most frequently diagnosed malignancy in the male genitourinary tract. However, the regulatory mechanism of competitive endogenous RNAs (ceRNAs) in PCa remains unclear. In this study, we first performed immune scores of mRNA data from 481 PCa samples using single-sample Gene Set Enrichment Analysis (ssGSEA). Based on the immune scores, we then evaluated the tumor immune microenvironment and analyzed 28 types of immune cells in PCa, we constructed a comprehensive network with four lncRNAs (MEG3, PCAT1, SNHG19, TRG-AS1), three miRNAs (hsa-miR-488-3p, hsa-miR-210-5p, hsa-miR-137), and twenty-seven mRNAs (including H2AFJ, THBS1, HPGD). Among the 28 immune cell types, seven immune cell types were found to be significantly associated with clinical characteristics. These network nodes have prognostic significance in multiple cancers and play critical roles in malignancy development, indicating the network’s predictive capability. We also observed a strong correlation (r = 0.6) between T-helper type 1 (Th1) cells and lncRNA network modules. The network connectivity highlights the association between immune therapy biomarkers for PCa, particularly those related to H2AFJ, THBS1, and HPGD. These findings provide valuable insights into the ceRNA regulatory network and its implications for immune-based therapies in PCa. Full article