Panoply™ Human CDK4 Knockdown Stable Cell Line

Lung cancer is the most common cancer and has a high mortality rate worldwide, with non-small cell lung cancer (NSCLC) accounting for approximately 85% of all cases. Numerous studies have shown that abnormal expression of microRNAs (miRNAs) is closely related to the occurrence and development of cancer. However, the clinical significance and biological functions of most miRNAs in NSCLC remain unclear. Here, researchers identified a novel miRNA, miR-34b-3p, and found that it can inhibit the growth of NSCLC cells, and explored its potential mechanisms. miR-34b-3p was found to be downregulated in both NSCLC tumor tissues and lung cancer cell lines (H1299 and A549). Overexpression of miR-34b-3p inhibited the growth of lung cancer cells (H1299 and A549), including inhibiting cell proliferation, inducing cell cycle arrest, and promoting apoptosis. Furthermore, luciferase reporter gene assays confirmed that miR-34b-3p can bind to the 3′-untranslated region (3′-UTR) of cyclin-dependent kinase 4 (CDK4) mRNA, thereby inhibiting CDK4 expression in NSCLC cells. The inhibition of proliferation in H1299 and A549 cells was mediated by cell cycle arrest and apoptosis caused by CDK4 interference. In addition, overexpression of CDK4 effectively reversed the inhibitory effect of miR-34b-3p on NSCLC cell growth. In summary, these findings suggest that miR-34b-3p may exert a tumor-suppressive effect in NSCLC by targeting CDK4, and therefore miR-34b-3p has the potential to be a biomarker for the diagnosis and treatment of NSCLC.

Here, researchers detected the expression level of CDK4 in human non-small cell lung cancer (NSCLC) samples using Western blot analysis. The results showed that the expression of CDK4 was significantly upregulated in NSCLC tissues compared to adjacent normal tissues (Figure 1A). Next, researchers constructed CDK4 knockdown H1299 and A549 cells (Figure 1B). CCK-8 assays showed that the viability of CDK4 knockdown H1299 and A549 cells was significantly reduced (Figure 1C, D), which was consistent with the phenotype caused by miR-34b-3p overexpression. Furthermore, cell cycle analysis showed that reduced CDK4 expression increased the proportion of cells in the G1 phase and decreased the proportion of cells in the S phase, leading to cell cycle arrest in the S phase (Figure 1E). Apoptosis detection showed that the apoptosis rate of CDK4 knockdown cells was significantly increased (Figure 1F). Therefore, these data suggest that CDK4 may act as an oncogene in NSCLC, promoting tumorigenesis and development by promoting cell proliferation, altering cell cycle distribution (transition from G1 to S phase), and inhibiting apoptosis.

Figure 1. Effects of CDK4 knockdown on cell growth in non-small-cell lung cancer. (Feng H, et al., 2019)