Search Results (260)

Background: The efficacy of chemotherapy in triple-negative breast cancer (TNBC) is limited by intrinsic resistance and the tumor microenvironment (TME). Accumulating evidence reveals a mechanistic connection between programmed death-ligand 1 (PD-L1) and c-x-c motif chemokine receptor 4 (CXCR4), which dominate stroma barriers, immune escape, and cancer metastasis. Earlier studies have shown that dual suppression of c-x-c motif ligand 12 (CXCL12)/CXCR4 and programmed cell death-1 (PD-1)/PD-L1 pathways regulates extracellular matrix (ECM) deposition, activation of cancer-associated fibroblasts (CAFs), and epithelial–mesenchymal transition (EMT) of pancreatic cancer cells. Methods: We combined BsNb PX4, a bispecific nanobody targeting PD-L1 and CXCR4, with paclitaxel or gemcitabine in multiple tumor cell lines and human peripheral blood mononuclear cell (hPBMC)-reconstituted xenograft mouse models. Antitumor activity was assessed by CCK-8, flow cytometry, and ELISA, and immune cell infiltration and TME remodeling were examined by immunofluorescence, immunohistochemistry, cytokine assays, and RNA-seq. Results: In MDA-MB-231 cells, BsNb PX4 synergistically enhanced paclitaxel-induced growth inhibition and apoptosis via G₂/M cycle arrest. This combinatorial strategy profoundly remodeled tumor immunity by expanding CD8⁺ T cells and depleting Foxp3⁺ CD4⁺ regulatory T cells (Tregs), while concurrently restoring T-cell cytotoxicity and skewing the cytokine balance toward an antitumor state, with elevated IFN-γ and reduced TGF-β1. Notably, compared with paclitaxel monotherapy, the combination significantly elevated intratumoral CD8⁺ T-cell infiltration, decreased Treg abundance, and exerted robust inhibitory effects on tumor growth and metastasis in humanized TNBC xenografts. Conclusions: These findings reveal that dual blockade of PD-L1 and CXCR4 acts synergistically with chemotherapy by triggering tumor cell apoptotic effects and reversing the immunosuppressive microenvironment, thereby emerging as a promising therapeutic strategy for TNBC. Full article

Pancreatic ductal adenocarcinoma (PDAC) is considered as one of the most lethal malignancies, characterized by late diagnosis, aggressive local invasion, profound therapy resistance, and a suppressive tumor microenvironment. Currently known chemotherapy regimens for the treatment of PDAC are limited and typically depend on the stage of disease. For pre-surgery and post-surgery settings, modified combination of fluorouracil, leucovorin, irinotecan, and oxaliplatin are used. Gemcitabine/nab-paclitaxel is an alternative regimen used for the disease at advanced stage. However, modest efficacy and high toxicity are often associated with these treatments. Therefore, more efficacious, safer, and novel therapeutic options are urgently required. The natural product curcumin has been shown to exert promising anti-inflammatory, pro-apoptotic, and antimetastatic activities in PDAC models. Inspired by these initial reports, there has been a sustained effort in the medicinal chemistry community to develop chemotherapeutic agents for the treatment of PDAC based on the chemical architecture of curcumin. This review highlights recent developments of multiple classes of curcumin analogs as a credible and versatile class of investigational agents for addressing the unmet therapeutic needs of pancreatic cancer. Full article

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy characterized by limited treatment options and poor prognosis. Gemcitabine is a commonly used chemotherapy; however, gemcitabine resistance in PDAC poses a critical barrier to effective treatment, as the underlying mechanisms are not yet fully understood. Methods: This study employs an exploratory untargeted metabolomics approach to investigate metabolic differences in PDAC cells in the presence and absence of gemcitabine treatment. HPAF-II, MIA PaCa-2, and BxPC-3 cell lines were used as models for gemcitabine-resistant, moderately responsive, and permissive PDAC cells, respectively. Results: MTT assay results revealed that BxPC-3 cells are highly sensitive to gemcitabine treatment, HPAF-II cells are the most resistant, and MIA PaCa-2 cells exhibit moderate sensitivity. Orthogonal Partial Least Squares Discriminant Analysis (OPLS-DA) of the metabolomics data demonstrated clear differentiation of gemcitabine-treated and untreated (control) cells. When comparing the treated vs. control conditions, 170 metabolites matched to an in-house library of standards were significant (p < 0.05 or fold change ≥ 2 or VIP ≥ 1) differentiators in HPAF-II cells, whereas MIA PaCa-2 and BxPC-3 cells had 178 and 218 differentiating metabolites, respectively. HPAF-II cells treated with gemcitabine had significantly higher levels of N-acetylneuraminic acid and 7-dehydrocholesterol compared with the control group. In contrast, these metabolites were significantly lower or non-significant in BxPC-3 treated cells. Pathway analysis revealed that the steroid biosynthesis pathway was significantly perturbed in HPAF-II cells, whereas amino sugar and nucleotide sugar metabolism was predominantly altered in BxPC-3 cells. Conclusions: Overall, this exploratory study reveals metabolic differences between treated and untreated cells to derive targeted therapeutic strategies that could be used in the future to improve treatment outcomes for PDAC patients. Full article

Gemcitabine-based chemotherapy has long served as a standard treatment for urothelial carcinoma (UC), particularly in perioperative and metastatic settings. However, therapeutic efficacy is frequently limited by intrinsic or acquired resistance. Gemcitabine functions as a prodrug whose activity depends on coordinated processes involving cellular uptake, intracellular activation, metabolic inactivation, and nucleotide metabolism. Increasing evidence suggests that resistance in UC is mediated by multiple interconnected mechanisms beyond alterations in gemcitabine transport, activation, and inactivation alone. Key molecular determinants include human equilibrative nucleoside transporter 1 (hENT1), deoxycytidine kinase (dCK), cytidine deaminase (CDA), and ribonucleotide reductase regulatory subunit M1 (RRM1), which is involved in nucleotide pool maintenance and DNA synthesis. In addition, replication stress responses, apoptosis evasion pathways, and tumor microenvironment-associated factors also contribute to gemcitabine resistance. Stress-adaptive pathways involving Y-box binding protein 1 (YB-1), hypoxia-inducible factor-1 alpha (HIF-1α), and autophagy-related mechanisms may further promote survival under chemotherapy-induced stress conditions. In addition, extracellular mucin-associated mechanisms may alter intratumoral drug accessibility and contribute to resistance. In this review, we summarize UC-specific evidence regarding gemcitabine resistance and discuss how these pathways collectively shape an integrated resistant phenotype. Full article

Drug resistance remains a significant barrier to achieving durable treatment responses. Traditionally, resistance has been attributed to genetic alterations and clonal selection. However, accumulating evidence suggests that early adaptation to therapy is often mediated by non-genetic state transitions. In this review, we propose a conceptual framework in which resistance emerges through therapy-driven molecular evolution in bladder cancer, characterized by three interconnected axes: non-genetic plasticity, metabolic reorganization, and tumor microenvironment remodeling. Using the Gemcitabine-Resistant Cell (GRC) model as a temporal reference system, we describe a stepwise transition from drug-sensitive states dominated by proliferation to survival-optimized resistant states through a growth–survival trade-off. Early adaptive phases are marked by the attenuation of cell-cycle and glycolytic programs, increased epigenetic flexibility, and metabolic rewiring involving mitochondrial and lipid-associated pathways. Later phases involve the reinforcement of resistance through extracellular matrix remodeling, developmental and stress-response signaling, and immunometabolic interactions within the tumor microenvironment, including adenosine- and lipid-associated mediators. Projecting the GRC score onto a clinical bladder cancer cohort further suggests that these evolutionary patterns may also be reflected in patient tumors. Overall, this framework supports a temporally structured view of chemoresistance and highlights opportunities to therapeutically target transitional adaptive states before resistance becomes stabilized. Full article

Pancreatic ductal adenocarcinoma (PDAC) presents unique treatment challenges, often due to the development of anti-cancer drug resistance. Previously, we demonstrated that CRISPR-directed gene ablation disabled the master regulator gene NRF2, a transcription factor known to control drug resistance in squamous cell carcinoma tumor cells, and restored chemosensitivity. In this short study, we evaluated a broad range of CRISPR/Cas9 molecules for their capacity to elicit similar responses in PDAC cells. Synthetic single guide RNAs (sgRNAs) were designed to target multiple functional domains encoded by NRF2. These molecules were delivered to cells via nucleofection, with outcomes analyzed by genotypic, phenotypic, and functional assays. We observed targeting efficiencies ranging from 25% to 100% with a high level of random insertions and deletions (indels). sgRNAs targeting exons 2, 3 and 4 demonstrated a high degree of genotypic, phenotypic and functional outcomes. Targeted disruption of exons 3 and 4 reveals significant loss of cell viability while overcoming drug resistance through the restoration of sensitivity to gemcitabine (>1.75 μM). Our study identifies domain-specific sites within NRF2 that, when disabled, restore sensitivity to gemcitabine, potentiating a more in-depth analysis of this novel augmentative therapeutic approach. Full article

Background: Fibrolamellar carcinoma (FLC) is a rare liver malignancy affecting adolescents. FLCs harbor a DNAJB1–PRKACA gene fusion that combines heat shock protein DNAJB1 with the catalytic subunit of protein kinase A. Surgery with systemic therapy provides 5-year survivals of 30–50%, but advanced disease remains largely incurable. Three-dimensional explants from 41 FLC patients were interrogated for drug sensitivity, resistance, and synergy against cytotoxics, targeted agents, and signal transduction inhibitors. Methods: Sterile specimens from histologically confirmed FLC patients were analyzed by Ex Vivo Analysis of Programmed Cell Death (EVA/PCD™) in a CLIA-licensed laboratory. Following mechanical and enzymatic disaggregation, explants underwent 72 h drug exposure. LC₅₀ values were derived from five-point dose–response curves and compared with a database of over 10,000 human tumor analyses. Synergy was assessed by combination index. In parallel, targeted metabolomic profiling was performed in five FLC patients using tandem MS/MS. Results: Forty-one samples were analyzed. Of 24 drugs selected, tumor-cell yields were adequate for testing in 18 (75%). Single-agent activity favored vorinostat, followed by phenformin and 6-diazo-5-oxo-L-norleucine. Combinations favored gemcitabine plus oxaliplatin (GEMOX) and 5-FU plus interferon. Metabolomic analysis identified distinct signature consistent with mitochondrial dysfunction and altered polyamine metabolism. Conclusions: The present findings are exploratory, and hypothesis-generating and should not be interpreted as evidence of clinical efficacy. Prospective clinical validation and mechanistic studies will be required to further define the therapeutic relevance of these observations in fibrolamellar carcinoma. Full article

Background: Aberrant glycosylation is closely associated with tumor progression, changes in the tumor microenvironment, and chemoresistance. This study aimed to identify prognostic sialylation-related genes in bladder cancer and define the role of ST3GAL6 in gemcitabine–cisplatin resistance. Methods: Molecular subtype analysis, prognostic analysis, and risk model construction were performed for sialylation-related genes using transcriptomic data and clinical information from the TCGA database. GC-resistant bladder cancer cell models were established for transcriptomic sequencing and untargeted metabolomic analysis. Cell proliferation and drug sensitivity assays were performed to evaluate the function of ST3GAL6. The regulatory relationship between IGF2BP3, ST3GAL6, and the PI3K pathway was further assessed by combining database analysis with molecular experiments. Results: Sialylation-related molecular patterns were associated with patient prognosis and tumor microenvironment features, particularly fibroblast-related characteristics, in bladder cancer. The key model gene ST3GAL6 was upregulated in bladder cancer tissues and was closely associated with prognosis. In GC-resistant bladder cancer cells, ST3GAL6 expression was significantly increased and accompanied by enhanced sialylation activity. ST3GAL6 promoted bladder cancer cell proliferation and reduced sensitivity to cisplatin and gemcitabine, at least in part through the PI3K-AKT-mTOR pathway. IGF2BP3 was also upregulated in resistant cells, is positively correlated with ST3GAL6, and may help maintain ST3GAL6’s expression by stabilizing its mRNA. Conclusions: Our findings suggest that aberrant sialylation is involved in bladder cancer progression and GC resistance. The IGF2BP3-ST3GAL6-PI3K/AKT/mTOR signaling axis may contribute to this process and may serve as a potential biomarker and therapeutic target in bladder cancer. Full article

Tumor Treating Fields (TTFields) represent a novel, non-invasive therapeutic modality in oncology that employs low-intensity, intermediate-frequency alternating electric fields to disrupt mitotic processes and induce cancer cell death. This review integrates mechanistic, preclinical, and emerging clinical evidence supporting the integration of TTFields with immunotherapeutic strategies in pancreatic ductal adenocarcinoma (PDAC). Although immunotherapy has transformed the treatment landscape across multiple malignancies, its efficacy in PDAC remains limited due to the tumor’s dense stroma, immunosuppressive microenvironment, and low immunogenicity. Preclinical investigations suggest that TTFields may potentiate immune-based therapies by enhancing antigen presentation, modulating the tumor microenvironment (TME), and attenuating mechanisms of immune resistance. We highlight studies evaluating TTFields in combination with immune checkpoint inhibitors (ICI), adoptive cellular therapies, and cancer vaccines, emphasizing their potential synergistic effects in PDAC. Clinically, the phase II PANOVA-2 trial demonstrated feasibility and encouraging survival outcomes with TTFields in combination with gemcitabine and nab-paclitaxel, providing the rationale for the ongoing phase III PANOVA-3 trial and the phase II PANOVA-4 trial, which combines TTFields with chemotherapy and atezolizumab. Additional clinical experiences in glioblastoma (GBM) and non-small-cell lung cancer (NSCLC) further substantiate the broader applicability of TTFields as an immunomodulatory adjunct. Remaining challenges include optimizing treatment sequencing, identifying predictive biomarkers, and managing TTFields-associated toxicities. Collectively, current evidence positions TTFields as a promising strategy to augment immunotherapy in PDAC, warranting further translational and clinical investigation to establish its role in reshaping therapeutic paradigms. Full article

Upper tract urothelial carcinoma (UTUC) is a rare and aggressive malignancy, accounting for only 5–10% of all urothelial carcinomas (UCs). Lung, bone, liver, and distant lymph nodes are common sites of metastasis, while gastrointestinal metastasis is extremely rare. We present a case of a 63-year-old female who developed a descending colon lesion 19 months after left radical nephroureterectomy for high-grade ureteral UC. The diagnosis was established by computed tomography (CT), magnetic resonance imaging (MRI), colonoscopy, and biopsy, which excluded primary colorectal malignancy. First-line therapy consisted of six 21-day cycles of gemcitabine plus cisplatin, followed by two cycles of tislelizumab maintenance immunotherapy. Restaging with contrast-enhanced CT and positron emission tomography/computed tomography (PET/CT) demonstrated disease progression. Despite switching to second-line nab-paclitaxel, the patient rapidly deteriorated from tumor cachexia and ultimately succumbed to septic shock secondary to severe pulmonary infection. This represents the first reported case of descending colon metastasis from primary ureteral UC. It highlights the colon as a potential metastatic site where biopsy is essential for definitive diagnosis. Notably, although the patient initially responded to platinum-based therapy, the subsequent rapid progression underscores the need for vigilant monitoring and timely adjustment of therapeutic strategies in managing such high-risk presentations. Full article

Cholangiocarcinoma (CCA) is a highly lethal, heterogeneous malignancy arising from the biliary tract. Although the prevalence of CCA is relatively low, its incidence has increased in the last few decades, and the overall prognosis is poor. Surgical resection remains the most efficacious treatment modality for CCA. However, due to its aggressive nature and often asymptomatic presentation, most patients are first diagnosed with advanced disease, precluding them from curative intervention. Moreover, due to its heterogeneity at the molecular, genomic, and epigenetic levels, drug treatment of CCA remains challenging. In this review, we discuss the current standard drug treatment approaches, recent breakthroughs, and promising new therapeutics for CCA. We summarize key clinical data for the standard first-line chemotherapy regimen and its efficacy and resistance mechanisms, along with more recent studies supporting or proposing second-line treatments. We highlight landmark clinical trials, including ABC-02, which established gemcitabine-cisplatin (GC) as the first-line regimen against biliary cancers. Additionally, we discuss recent findings on the susceptibility of CCA against targeted therapies and other immunologic molecules, including results from the KEYNOTE-966 and TOPAZ-1 clinical trials. Finally, we critically analyze new therapeutics in the preclinical and clinical space, such as CAR-T cells and oncolytic viruses that may be effective against CCA. Full article

Bladder cancer (BCa) is the second most common cancer of the genitourinary tract globally. It has limited treatment options, high recurrence rate, and acquires resistance to platinum-based therapy. Therefore, identifying novel therapeutic targets is urgently needed. Analysis of the TCGA data revealed that the enzyme galactokinase-1 (GALK1) is overexpressed (p < 0.0001) in bladder tumors compared to normal tissue. Our data also confirmed GALK1 protein upregulation in multiple human BCa cell lines and rodent bladder tumors. However, the precise role of GALK1 in BCa progression and effects of its specific inhibitor remain unexamined. In this study, we demonstrate that GALK1 gene silencing using shRNA resulted in a significant reduction in BCa cell proliferation, migration, and invasion. Pharmacological inhibition of GALK1 using small molecule Cpd36 resulted in anticancer efficacy against BCa. Cpd36 inhibited proliferation, migration, and invasion of BCa cells. Further, Cpd36 induced G1 phase cell cycle arrest, apoptosis, mitochondrial membrane depolarization, and ROS production in the BCa cells. Mechanistically, Cpd36-induced reduction in cell proliferation was associated with a decrease in expression of GALK1, PCNA proteins. Inhibition of metastatic potential was accompanied by decreased migration, invasion, and MMP-9 expression. Cell cycle arrest was associated with decrease in Cyclin D1 and increased expression of p21 and p27. Induction of apoptosis was linked with increased expression of cleaved caspase-3 and cleaved PARP, while downregulating p-AKT. Additionally, Cpd36 in combination with cisplatin or gemcitabine showed a strong synergistic effect on BCa cells. Taken together, our findings suggest that GALK1 plays a significant role in BCa cell survival and validates its inhibitors as promising therapeutic options for managing this disease. Full article

Leucine-rich repeat-containing 8A (LRRC8A; also known as SWELL1), the essential subunit of volume-regulated anion channels (VRACs), is amplified in multiple malignancies and has been implicated in tumor progression and therapeutic resistance. Three-dimensional (3D) cancer spheroids have been well-established as in vitro models that recapitulate characteristics of tumor stemness and intrinsic drug resistance. In the present study, spheroid formation in human breast cancer cell lines, YMB-1 and MDA-MB-468, conferred resistance to multiple anticancer drugs, including doxorubicin (DOX), gemcitabine (GEM), and 5-fluorouracil (5-FU), thereby mimicking the characteristic properties of breast cancer stem-like cells. LRRC8A expression was upregulated in 3D spheroids compared with adherent 2D monolayers, and its pharmacological inhibition induced membrane hyperpolarization accompanied by intracellular Cl⁻ accumulation. Inhibition of LRRC8A significantly sensitized spheroids to DOX, GEM, and 5-FU. Spheroid formation increased the expression of multidrug resistance-related protein 3 (MRP3) and the drug-metabolizing enzyme cytochrome P450 3A4 (CYP3A4), whereas LRRC8A inhibition suppressed their expression. The transcriptional upregulation of MRP3 and CYP3A4 was mediated through the NRF2–CEBPB/D transcriptional axis. Collectively, these findings suggest that LRRC8A inhibition may represent a therapeutic strategy to overcome chemoresistance by repressing MRP3 and/or CYP3A4 expression in breast cancer stem cells. Full article

Background. NOTCH receptors play a pivotal role in carcinogenesis. Upon ligand binding, a cascade of proteolytic cleavages mediated by ADAM proteases and the γ-secretase complex activates the receptor, ultimately releasing the NOTCH intracellular domain (NICD). NICD translocates to the nucleus, where it regulates gene expression. This review mainly aims to evaluate γ-secretase inhibitors (GSIs) as anticancer agents in preclinical and clinical settings, with a focus on their ability to block tumor progression, target cancer stem cells, and overcome resistance to standard therapies. Methods. A systematic search was conducted in the ISI Web of Science, PubMed, and Scopus databases, following PRISMA guidelines. The review included preclinical in vitro and in vivo studies, as well as clinical trials, investigating GSIs, either as monotherapy or in combination with other treatments, in TNBC, metastatic melanoma, PDAC, gastric cancer, and NSCLC. Exclusion criteria included duplicates, non-English articles, studies published before 2010, studies on non-cancer conditions, research unrelated to NOTCH signaling, and studies outside the selected cancer types. Overall, 69 articles were included and categorized into the five types of cancer analyzed (20 on NSCLC, 22 on TNBC, 11 on metastatic melanoma, 7 on GC, and 9 on PDAC). Of these, 60 studies corresponded to preclinical research in the types of cancer, and 9 studies corresponded to clinical trials in the types of cancer except for GC. Two independent authors screened and extracted relevant data, with disagreements resolved by the corresponding author. Findings were synthesized qualitatively across cancer types under study. Results. This review summarizes therapeutic advances involving GSIs in cancers driven by oncogenic NOTCH signaling, based on the 69 articles included. Preclinical studies show that GSIs synergize with chemotherapy and radiotherapy, particularly in NSCLC, melanoma, and TNBC, and block EMT, overcome therapeutic resistance, and improve prognosis. Commonly used GSIs include DAPT and RO4929097, which enhance the efficacy of agents, such as gemcitabine (PDAC), paclitaxel, osimertinib, erlotinib, and crizotinib (NSCLC), and 5-FU (gastric cancer, TNBC). Promising strategies include combining GSIs with SAHA, ATRA, CB-103, and other NOTCH signaling targeting molecules, either alone or with chemo- and radiotherapy. Clinical trials with GSIs, however, remain limited. RO4929097 is the most extensively tested GSI in clinical settings. PDAC trials combining GSIs with gemcitabine showed no benefit; melanoma trials yielded modest outcomes; and TNBC trials demonstrated partial responses to GSIs but overall low efficacy and significant adverse events. Discussion and Conclusions. Despite encouraging preclinical evidence, clinical trials with GSIs have underperformed, largely due to tumor heterogeneity, dosing limitations, and the non-selective nature of γ-secretase inhibition. Other NOTCH inhibitors, such as DLL4 antibodies, also resulted in partial responses and secondary effects. Future strategies should prioritize receptor-specific NOTCH inhibitors, patient stratification based on NOTCH pathway activation, and optimized combination regimens. Emerging approaches include integrating immunotherapy with advanced technologies such as CRISPR, CAR-T cells, and bispecific antibodies, as well as targeted delivery systems to enhance efficacy and reduce toxicity. Additional research directions include addressing the tumor microenvironment and EMT-driven resistance, elucidating the mechanisms of immune evasion, and inhibiting tumor angiogenesis. Finally, leveraging artificial intelligence and big-data-driven personalized medicine, including sex-specific considerations, will be essential for improving patient outcomes. Full article

Pancreatic ductal adenocarcinoma (PDAC) is characterized by immune cell dysfunction and poor prognosis. CD44, a cell surface glycoprotein with multiple splice variants, has been implicated in tumor progression, but its compartment-specific roles in PDAC remain unclear. CD44 standard and variant isoform expression was analyzed in patient-derived lymph nodes (LNs) by quantitative PCR. Immune cell-specific CD44 expression was assessed by flow cytometry in LNs and peripheral blood. Soluble and exosome-associated CD44 (exo-CD44) were measured in plasma. Clinical associations and survival analyses were performed. Transcriptomic, immune infiltration, immune checkpoint, and drug sensitivity analyses were conducted using TCGA-PAAD and pharmacogenomic datasets. CD44 standard isoform expression was unchanged in PDAC LNs, whereas multiple CD44 variant isoforms (v4–v10) were significantly reduced and associated with metastatic disease and poor survival, particularly CD44v5, v6, v7, and v10. CD44 expression was enriched in CD45⁺ immune cells, with highest levels in CD4⁺ T cells in both LNs and blood. Soluble CD44 levels showed no clinical associations. In contrast, exo-CD44 levels were reduced overall in PDAC but increased in patients with distant metastasis, positive resection margins, systemic inflammation, and reduced survival. High CD44 expression was associated with advanced disease, immune cell infiltration, immune checkpoint gene expression, reduced sensitivity to gemcitabine, paclitaxel, rapamycin, and FMK, and distinct CTLA4/PD-L1 checkpoint profiles. CD44 exhibits compartment-specific regulation in PDAC, linking immune remodeling, exosome signaling, and therapeutic resistance to adverse clinical outcome. Full article