Cry 1 Regulates the Clock Gene Network and Promotes Proliferation and Migration Via the Akt/P53/P21 Pathway in Human Osteosarcoma Cells

Abstract

The many circadian clock genes buildup a network structure that controls physiological processes such as sleep cycle, metabolism and hormone secretion. A close relationship exists between circadian rhythm and cancers because cell cycle is affected by clock controlled genes (CCGs), including Cyclin D1, Cyclin A, Cyclin E and P21. The abnormal expression of the core circadian clock gene Cryptochrome 1 (Cry1) was found in many types of cancers. However, it is still unclear the exact mechanism of Cry1 dysregulation influences carcinogenesis and progression of cancers. In this study, we investigated the role of Cry1 in regulating proliferation and migration of Hos and U2os human osteosarcoma cells by silencing Cry1 using short hairpin RNA interference. Our data from in vitro and in vivo experiments confirmed that Cry1 knockdown enhanced proliferation and migration of osteosarcoma cells. Then, Cry2, Per1, Per2, Per3, Bmal1 and Clock were found up regulated, while Dec1, Dec2, CK1ε and Npas2 were downregulated at mRNA level. Besides, Akt/P53/P21 signaling was activated after Cry1 silencing and Akt was negatively phosphorylated along with Cry1 expression, while enhanced progression of osteosarcoma cells by Cry1 knockdown was reversed when Akt inhibitor treated. Furthermore, the rescue experiment verified the Akt/P53/P21 was downstream genes of Cry1 to control osteosarcoma progression. Taken together, these findings provide a new insight into how Cry1 regulates clock gene network and promotes proliferation and migration in a Akt dependent manner in human osteosarcoma cells.

Non-circadian aspects of BHLHE40 cellular function in cancer

“…Moreover, in some tumors, BHLHE40 appears to have a bimodal function -it is upregulated during tumor initiation, whereas its expression is lost during tumor progression, exhibiting a significant decrease in expression from well-differentiated to poorly differentiated tumors. BHLHE40 is primarily a transcriptional regulator [28,61,37] that is often deleted or downregulated in cancer, including Burkitt's lymphoma [62], osteosarcoma [63], non-small cell lung cancer [64] and in pancreatic cancer [65]. Paradoxically, BHLHE40 is also upregulated in many cancers, such as in gastric cancer [66,67] and in breast cancer [68].…”

Analysis of Immune Infiltration Pattern in Osteosarcoma and Its Clinical Significance

“…The results of GSEA with c2.cp.kegg.v7.0.symbols.gmt as the reference gene set showed that the enrichment pathways were mainly involved in the circadian rhythm, oxidative phosphorylation, DNA replication and ECM-receptor interaction pathway. Previous reports have shown that oxidative phosphorylation [39,40], circadian rhythm [41], and DNA replication [42] were closely related to the occurrence and progress of OS. Another study has reported that ECM-receptor interaction pathway plays an important role in the occurrence, development, invasion and metastasis of malignant tumors [43].…”

The tumour suppressing role of the circadian clock

“…Downregulation of circadian clock genes in cancer cells has also been correlated with increased cell migration and invasion. Studies have shown that inhibition of CRY1 , PER2 or BMAL1 results in enhanced cell migration or invasion via the Akt signalling pathway, in osteosarcoma ( CRY1 and PER2 ) and lung cancer and glioma cells ( BMAL1 ). In addition, BMAL1 knockout, resulting in loss of circadian rhythmicity, results in increased invasion of breast cancer cells .…”