Effects of Substrate Stiffness on Epithelial-Mesenchymal Transition of Colon Cancer Cells under Simulated Hypoxia Environment / 医用生物力学

Objective To explore the effects from the synergy of substrate stiffness and hypoxia on epithelial mesenchymal transition (EMT) of colon cancer cells SW480 by simulating the microenvironment of human colon cancer tissues. Methods Polyvinyl alcohol gels with different stiffness ( 4. 5, 20, 40 kPa) were prepared to simulate the stiffness of each part of colon cancer tissues. The morphological change of cells on substrate with different stiffness was detected under simulated hypoxia ( CoCl2 ) environment. The expression of hypoxia inducible factor (HIF-1α), and EMT markers E-cadherin, Vimentin, Snail 1 were detected by Western blot. The mRNA expression of E-cadherin, Vimentin, Snail 1, matrix metalloproteinase-2 ( MMP-2), and MMP-9 was detected by quantitative real-time PCR ( qRT-PCR). Results Under simulated hypoxia environment, with the increase of substrate stiffness, the SW480 cells spreading area increased, and transformed from round shape into irregular polygon. The EMT of SW480 could be enhanced through up-regulating expression of Vimentin, Snail 1, MMP-2, MMP-9, and down-regulating expression of E-cadherin. Conclusions This study is important for exploring the synergistic effect of substrate stiffness and hypoxia on the EMT of colon cancer cells as well as the molecular mechanism.

Clinical analysis of 39 cases of multiple primary colorectal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the clinical features and prognosis of multiple primary colorectal carcinoma (MPCC).</p><p><b>METHODS</b>Among the 1462 patients with colorectal cancer admitted in our department from January 2000 to December 2007, 39 patients with MPCC were identified based on the Warran and Gates MPC diagnosis criteria. The age of onset, 5-year survival rate, lesion location and therapies were analyzed retrospectively.</p><p><b>RESULTS</b>The incidence of MPCC was 2.67% (39/1462). Eighteen of the patients had synchronous carcinomas and 21 were diagnosed to have metachronous carcinomas. Most of the tumors were located in the left colon and rectum. The average age of onset was (61.02∓13.94) in these patients who had an overall 5-year survival rate of 61.76%. The patients with metachronous carcinomas had a better prognosis than those with synchronous carcinomas. The 5-year survival rate of 3 early-stage cases (TNM stage I) was 100% after radical surgery. Thirty advanced cases underwent radical surgery combined with adjuvant chemotherapy, and their 1-, 3- and 5-year survival rates were 93.33%, 83.33%, and 73.33%, respectively. The 1- and 3-year survival rates of 3 advanced cases undergoing palliative surgery and adjuvant chemotherapy were 66.67% and 0, respectively. The 1- and 3-year survival rates of another 3 advanced cases with palliative chemotherapy were 66.67% and 0, respectively.</p><p><b>CONCLUSION</b>Early diagnosis and effective treatment can help prolong the survival of MPC patients. Surgical intervention and chemotherapy can improve the survival and prognosis of patients with advanced MPCC.</p>

CD133(+) Colo205 colorectal cancer cells express high levels of ALDH1 in serum-free culture / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the expression pattern of CD133 and ALDH1 in colorectal cancer cells line Colo205 cultured in serum-free medium (SFM) containing recombinant human epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF).</p><p><b>METHODS</b>Colo205 cells were cultured in serum-free medium (SFM) containing human recombinant EGF and bFGF or in serum-supplemented medium (SSM). The expression of CD133 was analyzed in both groups, and CD133(+) and CD133(-) cells sorted from the SFM group using flow cytometry and observed microscopically for their growth status. The expression of CD133 and ALDH1 in CD133(+) cells and CD133(-) cells was detected by immunofluorescence assay. CD133(+) cells and CD133(-) cells were then injected subcutaneously into NOD/SCID mice and the expression of ALDH1 in the tumor tissues was detected by immunohistochemistry.</p><p><b>RESULTS</b>The cells in SFM group showed a significantly higher percentage of CD133(+) cells than those in SSM group (P<0.05). In SFM, CD133(+) cells were capable of forming tumor spheres while CD133(-) cells could not; CD133(+)cells strongly expressed CD133 and ALDH1 and CD133(-) cells did not. In mice, tumors generated by CD133(+) cells, but not by CD133(-) cells, positively expressed ALDH1.</p><p><b>CONCLUSIONS</b>CD133(+) Colo205 colorectal cancer cells in SFM containing human recombinant EGF and bFGF can form tumor spheres and strongly express ALDH1. ALDH1 may be one of the candidate markers of colorectal cancer stem cells.</p>