The emerging evidence reveals that protein arginine methyltransferase 5 (PRMT5) is involved in regulation of tumour cell proliferation and cancer development. Nevertheless, the exact role of PRMT5 in human lung cancer cell proliferation and the underlying molecular mechanism remains largely obscure. Here, we showed that PRMT5 was highly expressed in human lung cancer cells and lung cancer tissues. Furthermore, we generated PRMT5 stable knockdown cell lines (A549 and H1299 cells) and explored the functions of PRMT5 in lung cancer cell proliferation. We found that the down‐regulation of PRMT5 by shRNA or the inhibition of PRMT5 by specific inhibitor GSK591 dramatically suppressed cyclin E1 and cyclin D1 expression and cell proliferation. Moreover, we uncovered that PRMT5 promoted lung cancer cell proliferation via regulation of Akt activation. PRMT5 was directly co‐localized and interacted with Akt, but not PTEN and mTOR. Down‐regulation or inhibition of PRMT5 markedly reduced Akt phosphorylation at Thr308 and Ser473, whereas the expression of PTEN and mTOR phosphorylation was unchanged, indicating that PRMT5 was an important upstream regulator of Akt and induced lung cancer cell proliferation. Altogether, our results indicate that PRMT5 promotes human lung cancer cell proliferation through direct interaction with Akt and regulation of Akt activity. Our findings also suggest that targeting PRMT5 may have therapeutic potential for treatment of human lung cancer.

In the previous studies, telocytes were found near the capillaries in many tissues, especially on the extracellular matrix of blood vessels and positive to CD34 and c-kit. Therefore, the present study aimed to explore if telocytes could produce angiogenesis associated cytokines, promote the proliferation and the angiogenesis of vascular endothelial cells in vitro. Human lung telocytes were isolated and cultured, and were identified by immunofluorescence cytochemistry with CD34, c-kit and vimentin. Telocytes conditional media (TCM) was prepared, and the expressions of angiogenesis associated cytokines in TCM were detected by ELISA. Human pulmonary microvascular endothelial cells (HPMECs) were cultured with DMEM media or TCM for 72 hours. The proliferation of HPMECs was continuously detected with CCK-8 kit at an interval of 12 hours. HPMECs were also injured by lipopolysaccharide, and cultured with TCM and DMEM respectively, and the tube formation capacity was detected. Telocytes were positive for CD34, c-kit and vimentin. The expressions of VEGF and EGF in TCM were significantly higher, the proliferation of HPMECs cultured with TCM significantly increased, and the tube formation of HPMECs injured by endotoxin was improved with the culture of TCM, as compared with the culture of DMEM. The present study provides the evidence that human lung telocytes could produce the growth factors, such as VEGF and EGF. Telocytes conditional media induced the proliferation of pulmonary endothelial cells and prevented from endotoxin-induced compromise of pulmonary endothelial angiogenesis.

Protein arginine methyltransferase 5 (PRMT5) is implicated in various types of human cancer and tumor development, especially in lung cancer. Nevertheless, it is still unclear whether suppression of PRMT5 could promote lung cancer cell apoptosis and chemosensitivity induced by resveratrol, and the underlying molecular mechanism remains completely unknown. Here, we showed that PRMT5 was overexpressed in human lung cancer tissues and different types of lung cancer cell lines. Moreover, we constructed PRMT5 stable knockdown cell lines (A549 and ASCT-a-1) and investigated the roles of PRMT5 and the related signaling pathway in lung cancer cell apoptosis induced by resveratrol. Our results indicated that inhibition or down-regulation of PRMT5 by GSK591, a PRMT5-specific inhibitor, or shRNAs markedly enhanced cell apoptosis and chemosensitivity stimulated by resveratrol. Further investigation showed that inhibition or down-regulation of PRMT5 further reduced Akt/GSK3β phosphorylation and the downstream targets cyclin D1 and E1 expression upon resveratrol treatment. Our findings suggest that PRMT5 is a pivotal mediator for human lung cancer cell death induced by resveratrol, which also reveals that PRMT5 may serve as a new therapeutic target for the treatment of human lung cancer.

The type II protein arginine methyltransferase 5 (PRMT5) has been engaged in various human cancer development and progression types. Nevertheless, few studies uncover the biological functions of PRMT5 in the epithelial-mesenchymal transition (EMT) of human lung cancer cells, and the associated molecular mechanisms and signaling cascades are entirely unknown. Here, we show that PRMT5 is the ectopic expression in human lung cancer tissues and cell lines. Further study reveals that silencing PRMT5 by lentivirus-mediated shRNA or blocking of PRMT5 by specific inhibitor GSK591 attenuates the expression levels of EMT-related markers in vivo, using the xenograft mouse model. Moreover, our results show that down-regulation of PRMT5 impairs EGFR/Akt signaling cascades in human lung cancer cells, whereas re-expression of PRMT5 recovers those changes, suggesting that PRMT5 regulates EMT probably through EGFR/Akt signaling axis. Altogether, our results demonstrate that PRMT5 serves as a critical oncogenic regulator and promotes EMT in human lung cancer cells. More importantly, our findings also suggest that PRMT5 may be a potential therapeutic candidate for the treatment of human lung cancer.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is an early characteristic of multiple organ dysfunction, responsible for high mortality and poor prognosis in patients. The present study aims to evaluate therapeutic effects and mechanisms of pyrrolidine dithiocarbamate (PDTC) on ALI.