High expression of the structural maintenance of chromosomes 5/6 complex is associated with the positive prognosis and doxorubicin susceptibility of colon cancer

Despite the exponential growth in colon cancer publications, our understanding of the tumorigenesis and progression problem is still limited. This study manifested the structural maintenance of chromosomes 5/6 complex (SMC5/6 complex) may serve as a prospective and novel biomarker for molecular diagnosis and therapeutics in patients with colon cancer. Dyregulation of SMC5/6 components is revealed to be dramatically correlated with the poor prognosis. Besides, ectopic expression of SMC5/6 components obviously impaired proliferation and migration capacity of colon cancer cells in vitro, and leaded to a restraint of the xenografted tumor growth in vivo. Moreover, overexpressed SMC5/6 components helped to enhance the doxorubicin (DOX) susceptibility of colon cancer cells by promoting apoptosis. The purpose of this article is to explore the clinical significance and molecular mechanism of SMC5/6 complex in colon cancer. Overall design: To analyze the biological mechanism of SMC5/6 complex that inhibit cell growth and promote DOX induced apoptosis, exon transcriptome sequencing (RNA-seq) of HCT116 with NSE4A and SMC5 overexpression were performed, as well as the vector-transfected (Con) HCT116 as the background value. HCT116 cells were transfected with the plasmid of vector, NSE4A-flag, and SMC5-flag respectively. 24 hours later, the transfected cells were divided into two portion, and one portion of cells were treated with DOX, while the other were not. The cells were cultured for 24 hours later, total RNA was extracted using Trizol reagent (Thermo Fisher, Waltham, MA, USA) according to the manufacturer`s instructions. Lastly, the concentration, quality and integrity of the total RNA were determined using a Nano Drop 2000 spectrophotometer (Thermo Scientific, Wilmington, DE, USA). The total RNA that had a standard of concentration 200ng/ml, mass 10mg and RNA integrity number (RIN) 8.0 was subjected to RNA-seq. Different gene and transcript expression was analyzed used TopHat and Cufflinks according to the protocol of the software.