Search

Abstract Background PAF1/PD2 deregulation contributes to tumorigenesis, drug resistance, and cancer stem cell maintenance in Pancreatic Cancer (PC). Recent studies demonstrate that metabolic reprogramming plays a role in PC progression, but the mechanism is poorly understood. Here, we focused on examining the role of PAF1/PD2 in the metabolic rewiring of PC. Methods Cell lines were transfected with shRNAs to knockdown PAF1/PD2. Metabolic genes regulated by PAF1/PD2 were identified by qPCR/western blot, and metabolic assays were performed. Immunoprecipitations/ChIP were performed to identify PAF1/PD2 protein partners and confirm PAF1/HIF1α sub-complex binding to LDHA. Results PAF1 and LDHA showed progressively increased expression in human pancreatic tumor sections. Aerobic glycolysis genes were downregulated in PAF1-depleted PC cells. Metabolic assays indicated a decreased lactate production and glucose uptake in knockdown cells. Furthermore, PAF1/PD2 depletion showed a reduced glycolytic rate and increased oxidative phosphorylation by ECAR and OCR analysis. Interestingly, we identified that HIF1α interacts and co-localizes with PAF1, specifically in PC cells. We also observed that the PAF1/PD2-HIF1α complex binds to the LDHA promoter to regulate its expression, reprogramming the metabolism to utilize the aerobic glycolysis pathway preferentially. Conclusion Overall, the results indicate that PAF1/PD2 rewires PC metabolism by interacting with HIF1α to regulate the expression of LDHA.

Abstract Resistance to the current Androgen Receptor Signaling Inhibitor (ARSI) therapies has led to higher incidences of therapy-induced neuroendocrine-like prostate cancer (t-NEPC). This highly aggressive subtype with predominant small-cell-like characteristics is resistant to taxane chemotherapies and has a dismal overall survival. t-NEPCs are mostly treated with platinum-based drugs with a combination of etoposide or taxane and have less selectivity and high systemic toxicity, which often limit their clinical potential. During t-NEPC transformation, adenocarcinomas lose their luminal features and adopt neuro-basal characteristics. Whether the adaptive neuronal characteristics of t-NEPC are responsible for such taxane resistance remains unknown. Pathway analysis from patient gene-expression databases indicates that t-NEPC upregulates various neuronal pathways associated with enhanced cellular networks. To identify transcription factor(s) (TF) that could be important for promoting the gene expression for neuronal characters in t-NEPC, we performed ATAC-Seq, acetylated-histone ChIP-seq, and RNA-seq in our NE-like cell line models and analyzed the promoters of transcriptionally active and significantly enriched neuroendocrine-like (NE-like) cancer-specific genes. Our results indicate that Pax5 could be an important transcription factor for neuronal gene expression and specific to t-NEPC. Pathway analysis revealed that Pax5 expression is involved in axonal guidance, neurotransmitter regulation, and neuronal adhesion, which are critical for strong cellular communications. Further results suggest that depletion of Pax5 disrupts neurite-mediated cellular communication in NE-like cells and reduces surface growth factor receptor activation, thereby, sensitizing them to docetaxel therapies. Moreover, t-NEPC-specific hydroxymethylation of Pax5 promoter CpG islands favors Pbx1 binding to induce Pax5 expression. Based on our study, we concluded that continuous exposure to ARSI therapies leads to epigenetic modifications and Pax5 activation in t-NEPC, which promotes the expression of genes necessary to adopt taxane-resistant NE-like cancer. Thus, targeting the Pax5 axis can be beneficial for reverting their taxane sensitivity.

Abstract Non-small cell lung carcinoma (NSCLC) exhibits a heightened propensity for brain metastasis, posing a significant clinical challenge. Mucin 5ac (MUC5AC) plays a pivotal role in the development of lung adenocarcinoma (LUAD); however, its role in causing brain metastases remains unknown. In this study, we aimed to investigate the contribution of MUC5AC to brain metastasis in patients with LUAD utilizing various brain metastasis models. Our findings revealed a substantial increase in the MUC5AC level in LUAD brain metastases (LUAD-BrM) samples and brain-tropic cell lines compared to primary samples or parental control cell lines. Intriguingly, depletion of MUC5AC in brain-tropic cells led to significant reductions in intracranial metastasis and tumor growth, and improved survival following intracardiac injection, in contrast to the observations in the control groups. Proteomic analysis revealed that mechanistically, MUC5AC depletion resulted in decreased expression of metastasis-associated molecules. There were increases in epithelial-to-mesenchymal transition, tumor invasiveness, and metastasis phenotypes in tumors with high MUC5AC expression. Furthermore, immunoprecipitation and proteomic analysis revealed a novel interaction of MUC5AC with Annexin A2 (ANXA2), which activated downstream matrix metalloproteases and facilitated extracellular matrix degradation to promote metastasis. Disrupting MUC5AC-ANXA2 signaling with a peptide inhibitor effectively abrogated the metastatic process. Additionally, treatment of tumor cells with an astrocyte-conditioned medium or the chemokine CCL2 resulted in upregulation of MUC5AC expression and enhanced brain colonization. In summary, our study demonstrates that the MUC5AC/ANXA2 signaling axis promotes brain metastasis, suggesting a potential therapeutic paradigm for LUAD patients with high MUC5AC expression.

Abstract Pancreatic ductal adenocarcinoma (PDAC) remains highly lethal due to limited therapeutic options and expensive/burdensome drug discovery processes. Utilizing genomic-data-driven Connectivity Mapping (CMAP) to identify a drug closer to real-world PC targeting may improve pancreatic cancer (PC) patient outcomes. Initially, we mapped CMAP data to gene expression from 106 PC patients, identifying nine negatively connected drugs. These drugs were further narrowed down using a similar analysis for PC cell lines, human tumoroids, and patient-derived xenografts datasets, where ISOX emerged as the most potent agent to target PC. We used human and mouse syngeneic PC cells, human and mouse tumoroids, and in vivo mice to assess the ability of ISOX alone and in combination with 5FU to inhibit tumor growth. Global transcriptomic and pathway analysis of the ISOX-LINCS signature identified HDAC 6/cMyc as the target axis for ISOX. Specifically, we discovered that genetic and pharmacological targeting of HDAC 6 affected non-histone protein cMyc acetylation, leading to cMyc instability, thereby disrupting PC growth and metastasis by affecting cancer stemness. Finally, KrasG12D harboring tumoroids and mice responded effectively against ISOX and 5FU treatment by enhancing survival and controlling metastasis incidence. Overall, our data validate ISOX as a new drug to treat advanced PC patients without toxicity to normal cells. Our study supports the clinical utility of ISOX along with 5FU in future PC clinical trials.

Summary: Although up to 80% small cell lung cancer (SCLC) patients’ response is good for first-line chemotherapy regimen, most patients develop recurrence of the disease within weeks to months. Here, we report cytostatic effect of leflunomide (Leflu) and teriflunomide (Teri) on SCLC cell proliferation through inhibition of DRP1 phosphorylation at Ser616 and decreased mitochondrial fragmentation. When administered together, Teri and carboplatin (Carbo) act synergistically to significantly inhibit cell proliferation and DRP1 phosphorylation, reduce abundance of intermediates in pyrimidine de novo pathway, and increase apoptosis and DNA damage. Combination of Leflu&Carbo has anti-tumorigenic effect in vivo. Additionally, lurbinectedin (Lur) and Teri potently and synergistically inhibited spheroid growth and depleted uridine and DRP1 phosphorylation in mouse tumors. Our results suggest combinations of Carbo and Lur with Teri or Leflu are efficacious and underscore how the relationship between DRP1/DHODH and mitochondrial plasticity serves as a potential therapeutic target to validate these treatment strategies in SCLC clinical trials.

Abstract Prostate cancer (PCa) progression leads to bone modulation in approximately 70% of affected men. A nutraceutical, namely, α-lipoic acid (α-LA), is known for its potent anti-cancer properties towards various cancers and has been implicated in treating and promoting bone health. Our study aimed to explore the molecular mechanism behind the role of α-LA as therapeutics in preventing PCa and its associated bone modulation. Notably, α-LA treatment significantly reduced the cell viability, migration, and invasion of PCa cell lines in a dose-dependent manner. In addition, α-LA supplementation dramatically increased reactive oxygen species (ROS) levels and HIF-1α expression, which started the downstream molecular cascade and activated JNK/caspase-3 signaling pathway. Flow cytometry data revealed the arrest of the cell cycle in the S-phase, which has led to apoptosis of PCa cells. Furthermore, the results of ALP (Alkaline phosphatase) and TRAP (tartrate-resistant acid phosphatase) staining signifies that α-LA supplementation diminished the PCa-mediated differentiation of osteoblasts and osteoclasts, respectively, in the MC3T3-E1 and bone marrow macrophages (BMMs) cells. In summary, α-LA supplementation enhanced cellular apoptosis via increased ROS levels, HIF-1α expression, and JNK/caspase-3 signaling pathway in advanced human PCa cell lines. Also, the treatment of α-LA improved bone health by reducing PCa-mediated bone cell modulation.

Claudins (CLDN1–CLDN24) are a family of tight junction proteins whose dysregulation has been implicated in tumorigeneses of many cancer types. In colorectal cancer (CRC), CLDN1, CLDN2, CLDN4, and CLDN18 have been shown to either be upregulated or aberrantly expressed. In the normal colon, CLDN1 and CLDN3–7 are expressed. Although a few claudins, such as CLDN6 and CLDN7, are expressed in CRC their levels are reduced compared to the normal colon. The present review outlines the expression profiles of claudin proteins in CRC and those that are potential biomarkers for prognostication.