Circadian clock circuitry in colorectal cancer

Figure 1 Biological clock and the cell processes involved in colorectal carcinogenesis. The scheme renders the transcriptional/translational feedback loop through which the molecular clockwork operates, and depicts its interplay with the aryl hydrocarbon receptor (AHR)/ARNT system in the control of the cell cycle and apoptosis, and ultimately in the regulation of the processes of cell proliferation and death, whose deregulation brings about colorectal cancer (CRC) onset and progression. CK: Casein kinase; AHR: Aryl hydrocarbon receptor; PPAR: Peroxisome proliferator-activated receptor; CHK: Checkpoint kinase; ATR: Ataxia telangiectasia and rad3-related; ATM: Ataxia telangiectasia mutated; ARNT: Aryl hydrocarbon receptor nuclear translocator; HLF: Hepatic leukaemia factor; TEF: Thyrotroph embryonic factor.