Objective To investigate the molecular mechanism of TNIK regulating actin cytoskeleton morphology in lung adenocarcinoma A549 cells, and determine its effects on the proliferation and apoptosis of the cancer cells when combined with mitosis-targeted drug. Methods RNA sequencing data were profiled to screen differentially expressed genes in the A549 cells with TNIK stable knockdown, and the expression of genes related to actin cytoskeleton assembly was subsequently detected. RT-PCR, Western blotting, and double immunofluorescence staining were preformed to analyze the molecular mechanism of TNIK regulating the assembly of actin-microtubule cytoskeleton system. Moreover, A549 cells with TNIK knockdown were treated with targeted antimitotic chemotherapeutic agent, paclitaxel, to observe the growth and apoptosis of the cancer cells. Results RNA-seq showed that the differentially expressed genes after TNIK knockdown were closely associated with mitotic progression. Further analysis revealed that TNIK knockdown significantly inhibited the expression of Rho pathway related genes including RhoA/B, ROCK1/2 and LIMK1 at the transcriptional level (P < 0.01), but had no obvious effect on the expression of Rac and CDC42 pathway related genes. Immunofluorescence assay indicated that TNIK knockdown resulted in abnormal mitosis and morphology in actin cytoskeleton system. As compared with the control cells, paclitaxel treatment decreased the proliferation (P < 0.01) while improved the apoptotic rate (P < 0.01) in TNIK knockdown cells. Conclusion TNIK regulates the morphology of actin-microtubule cytoskeleton system in lung adenocarcinoma A549 cells through the Rho/ROCK/LIMK1 pathway, and TNIK knockdown can enhance the efficiency of mitosis-targeted chemotherapeutic drug.
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