In vivo and in vitro effects of hyperplasia suppressor gene on the proliferation and apoptosis of lung adenocarcinoma A549 cells

MFN2 deficiency affects calcium homeostasis in lung adenocarcinoma cells via downregulation of UCP4

Mitofusin-2 (MFN2) is a transmembrane GTPase that regulates mitochondrial fusion and thereby modulates mitochondrial function. However, the role of MFN2 in lung adenocarcinoma remains controversial. Here, we investigated the effect of MFN2 regulation on mitochondria in lung adenocarcinoma. We found that MFN2 deficiency resulted in decreased UCP4 expression and mitochondrial dysfunction in A549 and H1975 cells. UCP4 overexpression restored ATP and intracellular calcium concentration, but not mtDNA copy number, mitochondrial membrane potential or reactive oxygen species level. Furthermore, mass spectrometry analysis identified 460 overlapping proteins after independent overexpression of MFN2 and UCP4; these proteins were significantly enriched in the cytoskeleton, energy production, and calponin homology (CH) domains. Moreover, the calcium signaling pathway was confirmed to be enriched in KEGG pathway analysis. We also found by protein-protein interaction network analysis that PINK1 may be a key regulator of MFN2- and UCP4-mediated calcium homeostasis. Furthermore, PINK1 increased MFN2/UCP4-mediated intracellular Ca²⁺ concentration in A549 and H1975 cells. Finally, we demonstrated that low expression levels of MFN2 and UCP4 in lung adenocarcinoma are associated with poor clinical prognosis. In conclusion, our data suggest not only a potential role of MFN2 and UCP4 in co-regulating calcium homeostasis in lung adenocarcinoma but also their potential use as therapeutic targets in lung cancer.

Ropivacaine inhibits proliferation, invasion, migration and promotes apoptosis of papillary thyroid cancer cells via regulating ITGA2 expression

The present study aimed to investigate the roles of Ropivacaine in papillary thyroid cancer (PTC) and identify the possible mechanisms. The expression of integrin alpha-2 (ITGA2) in TC cell lines was tested using Western blotting and RT-qPCR. Subsequently, the level of ITGA2 in human PTC cell line (TPC-1) was measured following intervention with a series of concentrations of Ropivacaine. Then, cell counting kit-8 (CCK-8) assay and colony formation assay were executed for detecting proliferation of cells after transfection with ITGA2 pcDNA3.1. The expression of proliferation-related protein was determined by Western blotting. Additionally, the abilities of TPC-1 cell invasion and migration were examined using Transwell assay and scratch wound healing assay. Apoptosis of TPC-1 cells was analyzed using TUNEL assay and the expressions of apoptosis-related proteins were tested via West blotting. The results suggested that ITGA2 was highly expressed in TC cell lines, especially in TPC-1 cells. Ropivacaine decreased the expression of ITGA2 in a dose-dependent manner. Moreover, after treatment with Ropivacaine, cell proliferation was inhibited accompanied by changes of proliferation-related protein expressions, which was reversed following co-transfection with ITGA2 pcDNA3.1. Furthermore, Ropivacaine concentration-dependently suppressed invasion and migration of TPC-1 cells, whereas these inhibitory effects were attenuated after ITGA2 overexpression. Furthermore, apoptosis was promoted, coupled with a decrease of Bcl-2 expression and increases of Bax, cleaved caspase-3 and cleaved caspase-9 expression, in Ropivacaine-treated TPC-1 cells, which was restored following ITGA2 overexpression. These findings demonstrated that Ropivacaine could suppress proliferation, invasion, migration, and accelerate apoptosis of PTC cells via regulating ITGA2 expression.

Overexpression of the hyperplasia suppressor gene inactivates airway fibroblasts obtained from a rat model of chronic obstructive pulmonary disease by inhibiting the Wnt signaling pathway

The present study aimed to investigate the effects of hyperplasia suppressor gene (HSG) overexpression on the activation of airway fibroblasts in a rat model of chronic obstructive pulmonary disease (COPD) and assess the underlying molecular mechanisms. The rat model of COPD was established by injection of papain and confirmed by hematoxylin and eosin staining. Airway fibroblasts were identified using immunofluorescence, and HSG expression was facilitated by an HSG vector. Cell viability, apoptosis and the levels of matrix metallopeptidase-9 (MMP-9), platelet-derived growth factor (PDGF), and transforming growth factor-β1 (TGF-β1) were measured via Cell Counting Kit-8, flow cytometry and ELISA analyses, respectively, and potential mechanisms were detected by reverse transcription-quantitative polymerase chain reaction and western blotting. Airway fibroblasts from COPD rats were isolated and identified based on vimentin expression. Compared with the control group, HSG overexpression reduced cell viability, promoted apoptosis, and reduced the protein levels of TGF-β1, MMP-9 and PDGF. Additionally, HSG overexpression reduced β-catenin and Ras homology family member A (RhoA) expression at both the mRNA and protein levels. Conversely, Wnt signaling pathway agonists lithium chloride (LiCl) and 4-ethyl-5,6-dihydro-5-methyl- (1,3)dioxolo(4,5-j)phenanthridine (HLY78), significantly reduced the effects of HSG overexpression (P<0.05 vs. HSG). Cell viability in the HSG + LiCl and HSG + HLY78 groups was increased, whereas apoptosis was reduced compared with HSG treatment alone. The protein levels of TGF-β1, MMP-9 and PDGF were also decreased in the HSG + LiCl and HSG + HLY78 groups compared with the HSG group (P<0.05). Furthermore, the expression of β-catenin and RhoA was higher in the HSG + LiCl and HSG + HLY78 groups compared with the HSG group (P<0.05). Collectively, the results indicated that HSG overexpression inactivated airway fibroblasts from COPD by inhibiting the Wnt signaling pathway.