Dehydroeffusol inhibits hypoxia-induced epithelial-mesenchymal transition in non-small cell lung cancer cells through the inactivation of Wnt/β-catenin pathway

Natural compounds: Wnt pathway inhibitors with therapeutic potential in lung cancer

The Wnt/β-catenin pathway is abnormally activated in most lung cancer tissues and considered to be an accelerator of carcinogenesis and lung cancer progression, which is closely related to increased morbidity rates, malignant progression, and treatment resistance. Although targeting the canonical Wnt/β-catenin pathway shows significant potential for lung cancer therapy, it still faces challenges owing to its complexity, tumor heterogeneity and wide physiological activity. Therefore, it is necessary to elucidate the role of the abnormal activation of the Wnt/β-catenin pathway in lung cancer progression. Moreover, Wnt inhibitors used in lung cancer clinical trials are expected to break existing therapeutic patterns, although their adverse effects limit the treatment window. This is the first study to summarize the research progress on various compounds, including natural products and derivatives, that target the canonical Wnt pathway in lung cancer to develop safer and more targeted drugs or alternatives. Various natural products have been found to inhibit Wnt/β-catenin in various ways, such as through upstream and downstream intervention pathways, and have shown encouraging preclinical anti-tumor efficacy. Their diversity and low toxicity make them a popular research topic, laying the foundation for further combination therapies and drug development.

Effect and Mechanism of Transthyretin over-Expression on Proliferation and Cell Cycle of Lung Cancer A549 Cells

Background

The effects of transthyretin (TTR) over-expression on the proliferation and cell cycle of non-small cell lung cancer (NSCLC) A549 cells and its possible mechanism were verified.

Methods

A total of 196 LC patients and 20 healthy controls were enrolled at Tianjin Hospital, Tianjin, China between Apr 2017 and Oct 2017. The serum TTR content was detected by ELISA. Through lentiviral transfection method, NSCLC cells were divided into non-transfected group (group A), negative control group (group B) transfected with empty vector and experimental group (group C) transfected with TTR over-expression. Cell proliferation was detected by CCK-8 method, TTR mRNA expression was detected by real-time quantitative polymerase chain reaction (RT-qPCR), and TTR protein expression was tested by Western blot (WB). Cell cycle was detected by flow cytometry, Wnt3a/β-catenin protein expression was detected by WB, and mRNA expression was detected by RT-qPCR.

Results

The serum TTR content in early, middle and late LC group was remarkably lower than that in healthy group (P<0.05). Compared with late stage, TTR content in early and middle stages of LC group was higher, and the difference was statistically marked (P < 0.05). The absorbance value of group C was lower than that of groups A and B, indicating that the cell proliferation activity dramatically decreased, with statistically marked difference (P<0.05). LC A549 cells in group C were obviously blocked in G2M, with statistical significance (P<0.05).

Conclusion

TTR over-expression can inhibit the proliferation of NSCLC A549 cells, and the expression is related to Wnt3a/β-catenin pathway. TTR in serum of patients was helpful for diagnosing LC and has certain clinical value.

PlGF knockdown attenuates hypoxia-induced stimulation of cell proliferation and glycolysis of lung adenocarcinoma through inhibiting Wnt/β-catenin pathway

Background

Angiogenic placental growth factor (PlGF) plays a role in hypoxia-induced angiogenesis. Here, we aimed to investigate the biological roles of PlGF in cell proliferation and glycolysis of lung adenocarcinoma (LUAD) and the underlying molecular mechanisms.

Methods

PlGF was knocked down in H358 and H1975 cells by lentiviruses, which were then cultured under hypoxia (90% N₂, 5%CO₂ and 5%O₂) for 24 h. PlGF was overexpressed in PC9 cells treated with XAV939, inhibitor of Wnt/β-catenin signaling pathway. PlGF-silencing H1975 cells were implanted into mice, and tumor xenografts were harvested and analyzed.

Results

Hypoxia treatment led to up-regulation of PlGF, C-myc, lactate dehydrogenase A (LDHA), and β-catenin, promotion of cell proliferation and glycolysis in H358 and H1975 cells, which were obviously reversed by knocking down PlGF. In tumors, PlGF knockdown significantly prohibited cell proliferation and glycolysis, and decreased expression of C-myc, LDHA, and β-catenin. PlGF overexpression markedly strengthened cell proliferation, which was inhibited by β-catenin knockdown. Consistently, XAV939, inhibitor of Wnt/β-catenin pathway, also inhibited PlGF-induced cell proliferation, glycolysis, and β-catenin expression in PC9 cells.

Conclusion

PlGF knockdown inhibited the stimulatory effect of hypoxia on cell proliferation and glycolysis of LUAD through deactivating Wnt/β-catenin pathway.