The impaction ofclock-knockdown on autophagy in 4T1 breast cancer cells

Circadian rhythm has been involved in the regulation of many physiological activities. Autophagy is the metabolic process that transports substances in the cytoplasm to the lysosomes for degradation, and involved in the process of many diseases, including cancer. Studies have shown that autophagy activity has a circadian rhythm feature. As the core gene of the circadian rhythm system, clock has participated in the occurrence and development of cancer. The expression of clock whether regulates tumor development by autophagy has not been illustrated at present. In this study, we established a stableclock-knockdown strain of mouse breast cancer cell 4T1 to explore the changes in autophagy activity. The results showed that autophagy-related proteins ATG9A, ATG7, LC3B and Beclin1 (ATG6) were down-regulated withclock-knockdown, and the p62, the key factors of autophagy, was up-regulated. Moreover,clock-knockdown caused significant up-regulation of p65, and inhibition of I kappa B alpha and p-AKT?which were the core factors of several signaling pathways involved in autophagy. Serum rhythm-inducing experiments behaved that the expression of LC3B and Beclin1 had rhythmic characteristics?differed from LC3A. The regulative geneclockwas initially established to regulate the autophagy-related genes, and the suggested direction of its regulatory pathways.