Expression of CDK6 in Stomach Cancer and the Effect of CDK4/6 Inhibitor PD-0332991 on the Function of Stomach Cancer Cells

Downregulation of CPT2 promotes proliferation and migration through the TNFα/NF-κB pathway in cholangiocarcinoma

Background

Carnitine palmitoyltransferase II (CPT2) is an important regulatory enzyme involved in fatty acid oxidation; it is associated with the prognosis and progression of colorectal and ovarian cancers, but its expression and role in cholangiocarcinoma (CCA) have been less explored. This study aims to explore the role and molecular mechanism of CPT2 in CCA and to determine the potential relationship between CPT2 expression and the prognosis of CCA patients.

Methods

Bioinformatics analyses were used to assess CPT2 expression in CCA and other cancers. Independent prognostic factors of CCA were identified for univariate and multivariate Cox regression analyses. Nomograms were employed to predict CCA 1-, 3-, and 5-year survival. Kaplan-Meier curves explored the correlation between CPT2 expression and CCA survival. We used time-dependent receiver operating characteristics (ROCs) to evaluate the predictive efficiency of CPT2. Furthermore, potential mechanisms of CPT2 were analyzed by Gene Set Enrichment Analysis (GSEA) in CCA. CPT2 expression in peripheral blood, tissues, and cell lines of CCA was verified by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting. The effect of CPT2 on CCA cells was gauged using Cell Counting Kit-8 (CCK-8), cell cycle, apoptosis, and transwell assays. Finally, the regulation of the TNFα/NF-κB pathway by CPT2 was verified by Western blotting.

Results

CPT2 expression was down-regulated in many cancers, including CCA. COX regression analyses showed that CPT2 expression and the clinical stage could be independent prognostic factors in CCA. Nomograms indicated that the lower probability of CCA survival was associated with the lower expression of CPT2 and the higher clinical stage. The Kaplan-Meier curve showed that the low expression of CPT2 was related to a poor prognosis in CCA. The time-dependent ROC curve demonstrated the predictive ability of CPT2 [1-, 3-, 5-year are under the curve (AUC) =0.933, 0.61, 0.612]. Functionally, CPT2 overexpression inhibited CCA cell proliferation, down-regulated CDK4/6 expression to arrest CCA cells at G1, induced apoptosis by up-regulating BAX expression, cleaved-caspase-3 expression, and down-regulating Bcl2 expression, and reduced migration and invasion via suppression of epithelial-mesenchymal transition (EMT). Knocking down CPT2 showed the opposite results. Mechanistically, overexpression of CPT2 could decrease TNFα and phosphorylated p65 (p-p65; Ser536) expression and inhibit NF-κB pathway activation. CPT2 knockdown yielded opposite results.

Conclusions

CPT2 is a potential prognostic marker of CCA, a tumor suppressor gene to inhibit the malignant progression of CCA, and therefore a potential therapeutic target.

Transcriptomic analyses of differentially expressed human genes, micro RNAs and long-non-coding RNAs in severe, symptomatic and asymptomatic malaria infection

Malaria transmission and endemicity in Africa remains hugely disproportionate compared to the rest of the world. The complex life cycle of P. falciparum (Pf) between the vertebrate human host and the anopheline vector results in differential expression of genes within and between hosts. An in-depth understanding of Pf interaction with various human genes through regulatory elements will pave way for identification of newer tools in the arsenal for malaria control. Therefore, the regulatory elements (REs) involved in the over- or under-expression of various host immune genes hold the key to elucidating alternative control measures that can be applied for disease surveillance, prompt diagnosis and treatment. We carried out an RNAseq analysis to identify differentially expressed genes and network elucidation of non-coding RNAs and target genes associated with immune response in individuals with different clinical outcomes. Raw RNAseq datasets, retrieved for analyses include individuals with severe (Gambia-20), symptomatic (Burkina Faso-15), asymptomatic (Mali-16) malaria as well as uninfected controls (Tanzania-20; Mali-36). Of the total 107 datasets retrieved, we identified 5534 differentially expressed genes (DEGs) among disease and control groups. A peculiar pattern of DEGs was observed, with individuals presenting with severe/symptomatic malaria having the highest and most diverse upregulated genes, while a reverse phenomenon was recorded among asymptomatic and uninfected individuals. In addition, we identified 141 differentially expressed micro RNA (miRNA), of which 78 and 63 were upregulated and downregulated respectively. Interactome analysis revealed a moderate interaction between DEGs and miRNAs. Of all identified miRNA, five were unique (hsa-mir-32, hsa-mir-25, hsa-mir-221, hsa-mir-29 and hsa-mir-148) because of their connectivity to several genes, including hsa-mir-221 connected to 16 genes. Six-hundred and eight differentially expressed long non coding RNA (lncRNA) were also identified, including SLC7A11, LINC01524 among the upregulated ones. Our study provides important insight into host immune genes undergoing differential expression under different malaria conditions. It also identified unique miRNAs and lncRNAs that modify and/or regulate the expression of various immune genes. These regulatory elements we surmise, have the potential to serve a diagnostic purpose in discriminating between individuals with severe/symptomatic malaria and those with asymptomatic infection or uninfected, following further clinical validation from field isolates.

Inhibition of Eukaryotic Initiating Factor eIF4E Overcomes Abemaciclib Resistance in Gastric Cancer

OBJECTIVE

Aberrant activating mutations in cyclin-dependent kinases 4 and 6 (CDK4/6) are common in various cancers, including gastroesophageal malignancies. Although CDK4/6 inhibitors, such as abemaciclib and palbociclib, have been approved for breast cancer treatment, their effectiveness as a monotherapy remains limited for gastroesophageal tumors. The present study explored the underlying mechanism of abemaciclib resistance.

METHODS

Abemaciclib-resistant gastric cancer cell lines were generated, and the phospho-eukaryotic translation initiation factor 4E (p-eIF4E) and eIF4E expression was compared between resistant and parental cell lines. In order to analyze the role of eIF4E in cell resistance, siRNA knockdown was employed. The effectiveness of ribavirin alone and its combination with abemaciclib was evaluated in the gastric cancer xenograft mouse model.

RESULTS

The upregulation of eIF4E was a common feature in gastric cancer cells exposed to prolonged abemaciclib treatment. Gastric cancer cells with increased eIF4E levels exhibited a better response to eIF4E inhibition, especially those that were resistant to abemaciclib. Ribavirin, which is an approved anti-viral drug, significantly improved the efficacy of abemaciclib, both in vitro and in vivo, by inhibiting eIF4E. Importantly, ribavirin effectively suppressed the abemaciclib-resistant gastric cancer growth in mice without causing toxicity.

CONCLUSION

These findings suggest that targeting eIF4E can enhance the abemaciclib treatment for gastric cancer, proposing the potential combination therapy of CDK4/6 inhibitors with ribavirin for advanced gastric cancer.

Retracted: Expression of CDK6 in Stomach Cancer and the Effect of CDK4/6 Inhibitor PD-0332991 on the Function of Stomach Cancer Cells

[This retracts the article DOI: 10.1155/2022/2402567.].

A strategy for the treatment of gastrointestinal cancer: Targeting tumor senescent cells

Gastrointestinal (GI) cancer includes a variety of cancers with high incidence that seriously threaten the lives of people worldwide. Although treatment strategies continue to improve, patient benefits are still very limited, and the ongoing search for new treatment strategies remains a priority. Cell senescence is closely related to the occurrence and development of tumors. For GI cancer, cell senescence may not only promote cancer but also bring new opportunities for treatment. Combined with relevant studies, we review the dual role of cell senescence in GI cancer, including the mechanism of inducing cell senescence, biomarkers of senescent cells, and potential of targeted senescence therapy for GI cancer.