Akt1 enhances CA916798 expression through mTOR pathway

CA916798 predicts poor prognosis and promotes Gefitinib resistance for lung adenocarcinoma

Background

Our previous studies have identified CA916798 as a chemotherapy resistance-associated gene in lung cancer. However, the histopathological relevance and biological function of CA916798 in lung adenocarcinoma (LUAD) remains to be delineated. In this study, we further investigated and explored the clinical and biological significance of CA916798 in LUAD.

Methods

The relationship between CA916798 and clinical features of LUAD was analyzed by tissue array and online database. CCK8 and flow cytometry were used to measure cell proliferation and cell cycle of LUAD after knockdown of CA916798 gene. qRT-PCR and western blotting were used to detect the changes of cell cycle-related genes after knockdown or overexpression of CA916798. The tumorigenesis of LUAD cells was evaluated with or without engineering manipulation of CA916798 gene expression. Response to Gefitinib was evaluated using LUAD cells with forced expression or knockdown of CA916798.

Results

The analysis on LUAD samples showed that high expression of CA916798 was tightly correlated with pathological progression and poor prognosis of LUAD patients. A critical methylation site in promoter region of CA916798 gene was identified to be related with CA916798 gene expression. Forced expression of CA916798 relieved the inhibitory effects of WEE1 on CDK1 and facilitated cell cycle progression from G2 phase to M phase. However, knockdown of CA916798 enhanced WEE1 function and resulted in G2/M phase arrest. Consistently, chemical suppression of CDK1 dramatically inhibited G2/M phase transition in LUAD cells with high expression of CA916798. Finally, we found that CA916798 was highly expressed in Gefitinib-resistant LUAD cells. Exogenous expression of CA916798 was sufficient to endow Gefitinib resistance with tumor cells, but interference of CA916798 expression largely rescued response of tumor cells to Gefitinib.

Conclusions

CA916798 played oncogenic roles and was correlated with the development of Gefitinib resistance in LUAD cells. Therefore, CA916798 could be considered as a promising prognostic marker and a therapeutic target for LUAD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-023-10735-3.

CA916798 gene expression is associated with multidrug resistance and predicts progression-free survival in patients with lung cancer

CA916798 has been identified as a novel multidrug resistance gene in lung cancer cells. However, the expression patterns of CA916798 in tumor tissues prior and subsequent to chemotherapy remain unclear. In the present study, CA916798 expression levels in tumor tissues prior and subsequent to chemotherapy were detected by reverse transcription-quantitative polymerase chain reaction and immunohistochemistry analysis. The prognostic significance of CA916798 expression in tumor tissues was explored by Kaplan-Meier survival analysis and Cox proportional hazards regression analysis. The messenger RNA (mRNA) and protein expression levels of CA916798 in tumor tissues were downregulated post-chemotherapy in chemotherapy-sensitive patients with lung cancer, but not in chemotherapy-resistant patients. Downregulation of CA916798 mRNA and protein expression post-chemotherapy was significantly associated with improved progression-free survival time. The findings from the present study suggest that platinum-based chemotherapy may induce the expression of CA916798, and CA916798 may be a promising biomarker to predict chemotherapy resistance and improve therapies for patients with lung cancer.

Shp2 confers cisplatin resistance in small cell lung cancer via an AKT-mediated increase in CA916798

The tyrosine phosphatase Shp2 is associated with tumorigenesis in small cell lung cancer (SCLC). However, the relationship between Shp2 and resistance to chemotherapy remains unclear. Here, we show that Shp2 plays an important role in inducing resistance to cisplatin-based chemotherapy via the SHP2-AKT-CA916798 pathway. In an SCLC cell line, overexpression of Shp2 induced cisplatin resistance and the increased expression of AKT, pAKT, pmTOR, and CA916798. Conversely, depletion of Shp2 in a cisplatin-resistant cell line via RNA interference increased cisplatin sensitivity and decreased AKT, pAKT, pmTOR, and CA916798 expression levels. Activation of AKT stimulated CA916798 expression and altered the level of Shp2. A mouse xenograft model verified the results obtained from the in vitro experiments. In addition, we collected and analyzed clinical SCLC specimens and found that Shp2 levels correlated with CA916798 expression in tumor tissues. Importantly, higher levels of Shp2 or CA916798 were associated with a poorer prognosis in SCLC patients who received chemotherapy. Together, our findings indicate that Shp2 induces cisplatin resistance in SCLC patients via the SHP2-AKT-CA916798 pathway. Therefore, Shp2 and CA916798 may be promising biomarkers for predicting resistance to chemotherapy and may function as targets for enhancing treatments.

[Effect of PI3K/AKT pathway on cisplatin resistance in non-small cell lung cancer]

Accumulating evidences indicate that aberrant activation of PI3K/AKT pathway in non-small cell lung cancer plays a vital role in tumor cell proliferation,apoptosis, and survival including drug resistance. Cisplatin as first-line chemotherapy are in widespread clinical use in patients with non-small cell lung cancer, however, the development of cisplatin resistance significantly impedes its clinic efficacy. Cisplatin resistance is a complicated process that various mechanisms participating in to interact, of which PI3K/AKT pathway keeping sustained activated is one of the most important reasons. This article reviewed the progress of research on the relationship between PI3K/AKT pathway and cisplatin resistance.

Valproic acid sensitizes pancreatic cancer cells to natural killer cell-mediated lysis by upregulating MICA and MICB via the PI3K/Akt signaling pathway

Background

Valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, is reported to exert anti-tumor effects by upregulating the expression of the natural killer group 2D (NKG2D) ligands on tumor cells; however, the mechanisms vary in different tumor types, and the effect and mechanism of action of VPA in pancreatic cancer cells are unknown.

Methods

The present study evaluated the effect of VPA to susceptibility of pancreatic cancer cells to the NK cell-mediated lysis in vitro and in vivo. Then we investigated the mechanism which the effect of VPA depend on.

Results

The lactate dehydrogenase assay (LDH) and xenograft experiment demonstrated that VPA significantly sensitized pancreatic cancer cells to NK cell-mediated lysis in vitro and in vivo. Quantitative real time- polymerase chain reaction (qRT-PCR) and flow cytometry demonstrated that VPA upregulated the mRNA and cell surface expression of the NKG2D ligands major histocompatibility complex class I-related chain A and B (MICA and MICB) in pancreatic cancer cells. Effects of VPA both in vitro and in vivo were significantly attenuated by the PI3K/Akt pathway inhibitor LY294002 or a siRNA targeting PI3K catalytic subunit alpha isoform (PI3KCA).

Conclusion

VPA enhances the susceptibility of pancreatic cancer cells to NK cell-mediated cytotoxicity both in vitro and in vivo by upregulating the expression of MICA and MICB via a PI3K/Akt signaling pathway-dependent mechanism.