Silencing GS Homeobox 2 Alleviates Gemcitabine Resistance in Pancreatic Cancer Cells by Activating SHH/GLI1 Signaling Pathway

Nrf2-mediated adenylosuccinate lyase promotes resistance to gemcitabine in pancreatic ductal adenocarcinoma cells through ferroptosis escape

Pancreatic cancer has one of the highest fatality rates and the poorest prognosis among all cancer types worldwide. Gemcitabine is a commonly used first-line therapeutic drug for pancreatic cancer; however, the rapid development of resistance to gemcitabine treatment has been observed in numerous patients with pancreatic cancer, and this phenomenon limits the survival benefit of gemcitabine. Adenylosuccinate lyase (ADSL) is a crucial enzyme that serves dual functions in de novo purine biosynthesis, and it has been demonstrated to be associated with clinical aggressiveness, prognosis, and worse patient survival for various cancer types. In the present study, we observed significantly lower ADSL levels in gemcitabine-resistant cells (PANC-1/GemR) than in parental PANC-1 cells, and the knockdown of ADSL significantly increased the gemcitabine resistance of parental PANC-1 cells. We further demonstrated that ADSL repressed the expression of CARD-recruited membrane-associated protein 3 (Carma3), which led to increased gemcitabine resistance, and that nuclear factor erythroid 2-related factor 2 (Nrf2) regulated ADSL expression in parental PANC-1 cells. These results indicate that ADSL is a candidate therapeutic target for pancreatic cancer involving gemcitabine resistance and suggest that the Nrf2/ADSL/Carma3 pathway has therapeutic value for pancreatic cancer with acquired resistance to gemcitabine.

Identification of Aberrant Expression of Gemcitabine-Targeting Proteins in Drug-Resistant Cells Using an Activity-Based Gemcitabine Probe

Gemcitabine-based monotherapy or combination therapy has become the standard treatment for locally advanced and metastatic pancreatic cancer. However, the emergence of resistance within weeks of treatment severely compromises therapeutic efficacy. The intricate biological process of gemcitabine resistance in pancreatic cancer presents a complex challenge, as the underlying mechanisms remain unclear. Identifying the target protein of gemcitabine is crucial for studying its drug-resistance mechanism. An activity-based probe is a powerful tool for studying drug target proteins, but the current lack of activity-based gemcitabine probes with robust biological activity hinders research on gemcitabine. In this study, we developed three active probes based on gemcitabine, among which Gem-3 demonstrated excellent stability and labeling efficacy. We utilized Gem-3 in conjunction with chemical proteomics to identify intracellular target proteins. We identified 79 proteins that interact with gemcitabine, most of which were previously unknown and represented various functional classes. Additionally, we validated the increased expression of IFIT3 and MARCKS in drug-resistant cells, along with the activation of the NF-κB signaling pathway. These findings substantially contribute to our comprehension of gemcitabine's target proteins and further our understanding of the mechanisms driving gemcitabine resistance in pancreatic cancer cells.

Unveiling the Molecular Mechanisms of Glioblastoma through an Integrated Network-Based Approach

Background/Objectives: Despite current treatments extending the lifespan of Glioblastoma (GBM) patients, the average survival time is around 15-18 months, underscoring the fatality of GBM. This study aims to investigate the impact of sample heterogeneity on gene expression in GBM, identify key metabolic pathways and gene modules, and explore potential therapeutic targets. Methods: In this study, we analysed GBM transcriptome data derived from The Cancer Genome Atlas (TCGA) using genome-scale metabolic models (GEMs) and co-expression networks. We examine transcriptome data incorporating tumour purity scores (TPSs), allowing us to assess the impact of sample heterogeneity on gene expression profiles. We analysed the metabolic profile of GBM by generating condition-specific GEMs based on the TPS group. Results: Our findings revealed that over 90% of genes showing brain and glioma specificity in RNA expression demonstrate a high positive correlation, underscoring their expression is dominated by glioma cells. Conversely, negatively correlated genes are strongly associated with immune responses, indicating a complex interaction between glioma and immune pathways and non-tumorigenic cell dominance on gene expression. TPS-based metabolic profile analysis was supported by reporter metabolite analysis, highlighting several metabolic pathways, including arachidonic acid, kynurenine and NAD pathway. Through co-expression network analysis, we identified modules that significantly overlap with TPS-correlated genes. Notably, SOX11 and GSX1 are upregulated in High TPS, show a high correlation with TPS, and emerged as promising therapeutic targets. Additionally, NCAM1 exhibits a high centrality score within the co-expression module, which shows a positive correlation with TPS. Moreover, LILRB4, an immune-related gene expressed in the brain, showed a negative correlation and upregulated in Low TPS, highlighting the importance of modulating immune responses in the GBM mechanism. Conclusions: Our study uncovers sample heterogeneity's impact on gene expression and the molecular mechanisms driving GBM, and it identifies potential therapeutic targets for developing effective treatments for GBM patients.

Hedgehog-Gli1-derived exosomal circ-0011536 mediates peripheral neural remodeling in pancreatic cancer by modulating the miR-451a/VGF axis

BACKGROUND

Hedgehog-Gli1 signaling induces development of two common neurological features seen in pancreatic ductal adenocarcinoma (PDAC): peripheral neural invasion (PNI) and peripheral neural remodeling (PNR). However, the underlying molecular mechanisms in cancer cells and nerves within Gli1-derived PNR have not previously been comprehensively analyzed.

METHODS

In this study, RNA sequencing was used to screen meaningful circRNAs in PNR. An in vitro model of PNR was subsequently constructed through a co-culture system comprising PDAC cells and murine dorsal root ganglia (DRG) (as the neuronal element), and the relevant mechanisms were explored using a series of molecular biology experiments. A subcutaneous nude mouse tumorigenesis model was established to further verify the occurrence of PNR that was detected in human PDAC samples.

RESULTS

We first confirmed the molecular mechanisms of PNR development through crosstalk between exosomal circ-0011536 and DRG. In Gli1-overpressed PDAC, circ-0011536 is mainly secreted by exosomes. After being ingested by DRG, it can promote the activity of DRG by degrading miR-451a and upregulating the expression of VGF. Overexpression of Gli1 can accelerate the proliferation of subcutaneous tumors in mice and is closely related to the density of nerve plexuses, while downregulating circ-RNA inhibits tumor proliferation and reduces the density of nerve plexuses. In addition, TMA results confirmed that Gli1 overexpression significantly increased the expression of VGF and was closely associated with increased nerve plexus density.

CONCLUSION

Hedgehog-Gli1-induced exosomal circ-0011536 promoted PNR via the miR-451a/VGF axis, thereby establishing that it may contribute to PDAC-associated nerve changes with activated Hedgehog signaling.

Pyroptosis-Related Signature Predicts the Progression of Ulcerative Colitis and Colitis-Associated Colorectal Cancer as well as the Anti-TNF Therapeutic Response

Ulcerative colitis (UC) is a complex intestinal inflammation with an increasing risk of colitis-associated colorectal cancer (CAC). However, the pathogenesis is still unclear between active UC and inactive UC. Recently, it has been reported that pyroptosis-related genes (PRGs) are closely associated with inflammatory disease activity. Nevertheless, the specific roles of PRGs in the progression and treatment of UC and CAC remain unclear. In this study, we identified 30 differentially expressed PRGs based on the immune landscape of active and inactive UC samples. Meanwhile, weighted gene coexpression network analysis was applied to explore important genes associated with active UC. By intersecting with the differentially expressed PRGs, CASP5, GBP1, GZMB, IL1B, and IRF1 were selected as key PRGs to construct a pyroptosis-related signature (PR-signature). Then, logistic regression analysis was performed to validate the PR-signature and establish a pyroptosis-related score (PR-Score). We demonstrated that PR-Score had a powerful ability to distinguish active UC from inactive UC in multiple datasets. Besides, PR-Score was positively correlated with immune cell infiltration and inflammatory microenvironment in UC. Lower PR-Score was associated with a better response to anti-TNF therapy for patients with UC. Additionally, high-PR-Score was found to suppress CAC and improve the survival outcomes of patients with colorectal cancer. Finally, the levels of the PR-signature genes were validated both in vitro and in vivo. These findings can improve our understanding of PRGs in UC and provide new markers for predicting the occurrence of active UC or CAC and the treatment of UC.

Regulation of pancreatic cancer therapy resistance by chemokines

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy characterized by high resistance and poor response to chemotherapy. In addition, the poorly immunogenic pancreatic tumors constitute an immunosuppressive tumor microenvironment (TME) that render immunotherapy-based approaches ineffective. Understanding the mechanisms of therapy resistance, identifying new targets, and developing effective strategies to overcome resistance can significantly impact the management of PDAC patients. Chemokines are small soluble factors that are significantly deregulated during PDAC pathogenesis, contributing to tumor growth, metastasis, immune cell trafficking, and therapy resistance. Thus far, different chemokine pathways have been explored as therapeutic targets in PDAC, with some promising results in recent clinical trials. Particularly, immunotherapies such as immune check point blockade therapies and CAR-T cell therapies have shown promising results when combined with chemokine targeted therapies. Considering the emerging pathological and clinical significance of chemokines in PDAC, we reviewed major chemokine-regulated pathways leading to therapy resistance and the ongoing endeavors to target chemokine signaling in PDAC. This review discusses the role of chemokines in regulating therapy resistance in PDAC and highlights the continuing efforts to target chemokine-regulated pathways to improve the efficacy of various treatment modalities.