CHD4 promotes acquired chemoresistance and tumor progression by activating the MEK/ERK axis

TRIM29 facilitates gemcitabine resistance via MEK/ERK pathway and is modulated by circRPS29/miR-770-5p axis in PDAC

AIMS

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Chemotherapy based on gemcitabine (GEM) remains the first-line drug for patients with advanced PDAC. However, GEM resistance impairs its therapeutic effectiveness. Therefore, identifying effective therapeutic targets are urgently needed to overcome GEM resistance.

METHODS

The clinical significance of Tripartite Motif Containing 29 (TRIM29) was identified by exploring GEO datasets and TCGA database and its potential biological functions were predicted by GSEA analysis. The regulatory axis was established by bioinformatics analysis and validated by mechanical experiments. Then, in vitro and in vivo assays were performed to validate the roles of TRIM29 in PDAC GEM resistance.

RESULTS

High TRIM29 expression was associated with poor prognosis of PDAC and functional experiments demonstrated that TRIM29 promoted GEM resistance in PDAC GEM-resistant (GR) cells. Furthermore, we revealed that circRPS29 promoted TRIM29 expression via competitive interaction with miR-770-5p and then activated MEK/ERK signaling pathway. Additionally, both in vitro and in vivo functional experiments demonstrated that circRPS29/miR-770-5p/TRIM29 axis promoted PDAC GEM resistance via activating MEK/ERK signaling pathway.

CONCLUSION

Our results identify the significance of the signaling axis, circRPS29/miR-770-5p/TRIM29-MEK/ERK, in PDAC GEM resistance, which will provide novel therapeutic targets for PDAC treatment.

Diallyl disulfide antagonizes DJ-1 mediated proliferation, epithelial-mesenchymal transition, and chemoresistance in gastric cancer cells

Diallyl disulfide (DADS), an organic component of allicin abstracted from garlic, possesses multi-target antitumor activity. DJ-1 performs a vital function in promoting AKT aberrant activation via down-regulating phosphatase and tensin homologue (PTEN) in tumors. It is unknown the involvement of DJ-1 in epithelial-mesenchymal transition (EMT) of gastric cancer (GC) cells. The purpose of this study is to investigate whether diallyl disulfide (DADS) intervenes in the role of DJ-1 in GC. Based on the identification that the correlation between high DJ-1 and low PTEN expression in GC was implicated in clinical progression, we illuminated that down-regulation of DJ-1 by DADS aided in an increase in PTEN expression and a decrease in phosphorylated AKT levels, which was in line with the results manifested in the DJ-1 knockdown and overexpressed cells, concurrently inhibiting proliferation, EMT, migration, and invasion. Furthermore, the antagonistic effects of DADS on DJ-1 were observed in in vivo experiments. Additionally, DADS mitigated the DJ-1-associated drug resistance. The current study revealed that DJ-1 is one of potential targets for DADS, which hopefully provides a promising strategy for prevention and adjuvant chemotherapy of GC.

FAM120A deficiency improves resistance to cisplatin in gastric cancer by promoting ferroptosis

The occurrence of chemoresistance is an inescapable obstacle affecting the clinical efficacy of cisplatin in gastric cancer (GC). Exploring the regulatory mechanism of cisplatin resistance will help to provide potential effective targets for improving the prognosis of gastric cancer patients. Here, we find that FAM120A is upregulated in GC tissues and higher in cisplatin-resistant GC tissues, and its high expression is positively correlated with the poor outcome of GC patients. Functional studies indicate that FAM120A confers chemoresistance to GC cells by inhibiting ferroptosis. Mechanically, METTL3-induced m6A modification and YTHDC1-induced stability of FAM120A mRNA enhance FAM120A expression. FAM120A inhibits ferroptosis by binding SLC7A11 mRNA and enhancing its stability. FAM120A deficiency enhances cisplatin sensitivity by promoting ferroptosis in vivo. These results reveal the function of FAM120A in chemotherapy tolerance and targeting FAM120A is an effective strategy to alleviate cisplatin resistance in GC.

Exosome circATP8A1 induces macrophage M2 polarization by regulating the miR-1-3p/STAT6 axis to promote gastric cancer progression

Circular RNAs (circRNAs) play important roles in gastric cancer progression but the regulatory role of circRNAs in controlling macrophage function remains elusive. Exosomes serve as cargo for circRNAs and play a crucial role as mediators in facilitating communication between cancer cells and the tumor microenvironment. In this study, we found that circATP8A1, a previously unreported circular RNA, is highly expressed in both gastric cancer tissues and exosomes derived from plasma. Increased circATP8A1 was associated with advanced TNM stage and worse prognosis in patients with gastric cancer. We showed that  the circATP8A1 knockdown significantly inhibited gastric cancer proliferation and invasion in vitro and in vivo. Functionally, exosome circATP8A1 induced the M2 polarization of macrophages through the STAT6 pathway instead of the STAT3 pathway. Mechanistically, circATP8A1 was shown to activate the STAT6 pathway through competitive binding to miR-1-3p, as confirmed by Fluorescence In Situ Hybridization (FISH), RNA immunoprecipitation, RNA pulldown, and Luciferase reporter assays. The reversal of circATP8A1-induced STAT6 pathway activation and macrophage polarization was observed upon blocking miR-1-3p. Macrophages treated with exosomes from gastric cancer cells overexpressing circATP8A1 were able to promote gastric cancer migration, while knockdown of circATP8A1 reversed these effects in vivo. In summary, exosome-derived circATP8A1 from gastric cancer cells induce macrophages M2 polarization via the circATP8A1/miR-1-3p/STAT6 axis, and tumor progression. Our results highlight circATP8A1 as a potential prognostic biomarker and therapeutic target in gastric cancer.

Identification of three lncRNA-related prognostic signatures in gastric cancer by integrated multi-omics analysis

Aims: The systematic identification of molecular features correlated with the clinical status of gastric cancer (GC) in patients is significant, although such investigation remains insufficient. Methods: GC subtyping based on RNA sequencing, copy number variation and DNA methylation data were derived from The Cancer Genome Atlas program. Prognostics lncRNA biomarkers for GC were identified by univariate Cox, LASSO and SVM-RFE analysis. Results: Three molecular subtypes with significant survival discrepancies, and their specific DEmRNAs and DElncRNAs were identified. Three reliable prognostic-associated lncRNA, including LINC00670, LINC00452 and LINC00160, were selected for GC. Conclusion: Our findings expanded the understanding on the regulatory network of lncRNAs in GC, providing potential targets for prognosis and treatment of GC patients.

Pleckstrin-2 promotes tumour immune escape from NK cells by activating the MT1-MMP-MICA signalling axis in gastric cancer

Immune escape is a major challenge in tumour immunotherapy. Pleckstrin-2(PLEK2) plays a critical role in tumour progression, but its role in immune escape in gastric cancer (GC) remains uncharacterized. RNA sequencing was used to explore the differentially expressed genes in a GC cell line that was resistant to the antitumor effect of Natural killer (NK) cells. Apoptosis and the expression of IFN-γ and TNF-α were detected by flow cytometry (FCM). PLEK2 expression was examined by Western blotting and immunohistochemistry (IHC). PLEK2 was upregulated in MGC803R cells that were resistant to the antitumor effect of NK cells. PLEK2 knockout increased the sensitivity of GC cells to NK cell killing. PLEK2 expression was negatively correlated with MICA and positively correlated with MT1-MMP expression both in vitro and in vivo. PLEK2 promoted Sp1 phosphorylation through the PI3K-AKT pathway, thereby upregulating MT1-MMP expression, which ultimately led to MICA shedding. In mouse xenograft models, PLEK2 knockout inhibited intraperitoneal metastasis of GC cells and promoted NK cell infiltration. In summary, PLEK2 suppressed NK cell immune surveillance by promoting MICA shedding, which serves as a potential therapeutic target for GC.

Dysregulated Signalling Pathways Driving Anticancer Drug Resistance

One of the leading causes of death worldwide, in both men and women, is cancer. Despite the significant development in therapeutic strategies, the inevitable emergence of drug resistance limits the success and impedes the curative outcome. Intrinsic and acquired resistance are common mechanisms responsible for cancer relapse. Several factors crucially regulate tumourigenesis and resistance, including physical barriers, tumour microenvironment (TME), heterogeneity, genetic and epigenetic alterations, the immune system, tumour burden, growth kinetics and undruggable targets. Moreover, transforming growth factor-beta (TGF-β), Notch, epidermal growth factor receptor (EGFR), integrin-extracellular matrix (ECM), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), phosphoinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR), wingless-related integration site (Wnt/β-catenin), Janus kinase/signal transducers and activators of transcription (JAK/STAT) and RAS/RAF/mitogen-activated protein kinase (MAPK) signalling pathways are some of the key players that have a pivotal role in drug resistance mechanisms. To guide future cancer treatments and improve results, a deeper comprehension of drug resistance pathways is necessary. This review covers both intrinsic and acquired resistance and gives a comprehensive overview of recent research on mechanisms that enable cancer cells to bypass barriers put up by treatments, and, like "satellite navigation", find alternative routes by which to carry on their "journey" to cancer progression.