Acquired resistance to temsirolimus is associated with integrin α7 driven chemotactic activity of renal cell carcinoma in vitro

Integrin alpha 7 correlates with poor clinical outcomes, and it regulates cell proliferation, apoptosis and stemness via PTK2-PI3K-Akt signaling pathway in hepatocellular carcinoma

This study aimed to evaluate the correlation of integrin alpha 7 (ITGA7) with clinical outcomes and its effect on cell activities as well as stemness in hepatocellular carcinoma (HCC). HCC tumor tissues and paired adjacent tissues from 90 HCC patients were obtained and ITGA7 expression was detected using immunohistochemistry assay. Cellular experiments were conducted to examine the effect of ITGA7 on cell activities, astemness via ITGA7 ShRNA transfection, and compensation experiments were further performed to test whether ITGA7 functioned via regulating PTK2-PI3K-AKT signaling pathway. ITGA7 was overexpressed in tumor tissues compared with paired adjacent tissues and its high expression was correlated with larger tumor size, vein invasion and advanced Barcelona Clinic Liver Cancer stage, and it also independently predicted worse overall survival in HCC patients. In cellular experiments, ITGA7 was upregulated in SMMC-7721, Hep G2, HuH-7 and BEL-7404 cell lines compared with normal human liver cells HL-7702. ITGA7 knockdown suppressed cell proliferation but promoted apoptosis, and it also downregulated CSCs markers (CD44, CD133 and OCT-4) as well as PTK2, PI3K and AKT expressions in SMMC-7721 and Hep G2 cell lines. ITGA7 overexpression promoted cell proliferation but inhibited apoptosis, and it also upregulated CSCs markers in HL-7702 cells. Further compensation experiments verified that ITGA7 regulated cell proliferation, apoptosis and CSCs markers via PTK2-PI3K-Akt signaling pathway. ITGA7 negatively associates with clinical outcomes in HCC patients, and it regulates cell proliferation, apoptosis and CSCs markers via PTK2-PI3K-Akt signaling pathway.

Correlation of integrin alpha 7 with clinicopathological characteristics and survival profiles, as well as its regulatory role in cell proliferation, apoptosis, and stemness in non-small-cell lung cancer

Background

The present study aimed to evaluate the correlation of integrin alpha 7 (ITGA7) with patients' clinicopathological characteristics and survival profiles, as well as its influence on cell proliferation, apoptosis, and stemness in non–small‐cell lung cancer (NSCLC).

Methods

A total of 397 NSCLC patients underwent surgical resection were included, and ITGA7 was measured in tumor tissues and adjacent tissues by immunohistochemistry. patients' clinical data were extracted from database, and follow‐up records were reviewed. In cellular experiments, expression of ITGA7 was measured in NSCLC cell lines and normal human lung epithelial cell line by RT‐qPCR. The influence of ITGA7 on cell activity was assessed by transfecting overexpression plasmids and knockdown plasmids of ITGA7 into A549 cells.

Results

Integrin alpha 7 was upregulated in tumor tissues compared with the adjacent tissues of NSCLC patients. Patients with ITGA7 high expression presented poorer pathological differentiation, larger tumor size, and more advanced TNM stage compared with patients with ITGA7 low expression. For survival profiles, both disease‐free survival and overall survival were shorter in ITGA7 high expression patients compared with ITGA7 low expression patients. In cellular experiments, ITGA7 was upregulated in NCI‐H1650, A549, HCC‐827, and NCI‐H1299 cells compared with normal human lung epithelial cells BEAS‐2B. In addition, ITGA7 promoted cell proliferation, inhibited cell apoptosis, and facilitated cell stemness in A549 cells.

Conclusion

Integrin alpha 7 correlates with poor clinicopathological characteristics and survival profiles, and it promotes cell proliferation, stemness but suppresses cell apoptosis in NSCLC.

Mechanisms behind Temsirolimus Resistance Causing Reactivated Growth and Invasive Behavior of Bladder Cancer Cells In Vitro

Background: Although mechanistic target of rapamycin (mTOR) inhibitors, such as temsirolimus, show promise in treating bladder cancer, acquired resistance often hampers efficacy. This study evaluates mechanisms leading to resistance. Methods: Cell growth, proliferation, cell cycle phases, and cell cycle regulating proteins were compared in temsirolimus resistant (res) and sensitive (parental—par) RT112 and UMUC3 bladder cancer cells. To evaluate invasive behavior, adhesion to vascular endothelium or to immobilized extracellular matrix proteins and chemotactic activity were examined. Integrin α and β subtypes were analyzed and blocking was done to evaluate physiologic integrin relevance. Results: Growth of RT112res could no longer be restrained by temsirolimus and was even enhanced in UMUC3res, accompanied by accumulation in the S- and G2/M-phase. Proteins of the cdk-cyclin and Akt-mTOR axis increased, whereas p19, p27, p53, and p73 decreased in resistant cells treated with low-dosed temsirolimus. Chemotactic activity of RT112res/UMUC3res was elevated following temsirolimus re-exposure, along with significant integrin α2, α3, and β1 alterations. Blocking revealed a functional switch of the integrins, driving the resistant cells from being adhesive to being highly motile. Conclusion: Temsirolimus resistance is associated with reactivation of bladder cancer growth and invasive behavior. The α2, α3, and β1 integrins could be attractive treatment targets to hinder temsirolimus resistance.