JNK信号通路介导MDR1/P-gp调控人结肠癌多药耐药

P27 expression in colorectal cancer: Significance and correlation with expression of Ki-67, P170, MLH1, MSH2, and MSH6

AIM: To investigate the relationship between P27 expression and tumor invasion, metastasis, multidrug resistance and prognosis of colorectal cancer (CRC), and to explore the possible mechanisms involved.

METHODS: Two hundred and sixty-three sporadic CRC patients who underwent surgery in the Department of Colorectal Surgery, Beijing Cancer Hospital from March 2008 to March 2012 were included in this study. All patients were diagnosed by histological examination and did not undergo chemoradiotherapy before surgery. Immunohistochemistry was used to detect P27, Ki-67, P170, MLH1, MSH2 and MSH6 protein expression in samples from these patients. The association between expression and clinical data was analysed retrospectively.

RESULTS: The positive rates of P27, Ki-67, P170, MLH1, MSH2 and MSH6 expression in CRC were 71.1%, 81.4%, 82.5%, 86.7%, 87.8% and 71.1%, respectively. Deficient expression of P27 was closely associated with tumour size, location, differentiation, invasion depth, vascular invasion and lymph node metastasis, but had no association with patients' gender, age, or tumor macroscopic morphology. P27 expression was negatively correlated with Ki-67 and P170 expression (r = -0.315, -0.163, P = 0.00, 0.01), but positively with MLH1, MSH2 and MSH6 expression (r = 0.129, 0.136, 0.159, P = 0.03, 0.03, 0.01).

CONCLUSION: P27 expression is closely associated with the development, invasion and metastasis of CRC. P27 protein expression can be regarded as an important parameter for evaluation of colorectal cancer progression and for selection of chemotherapy drugs and prevention of multidrug resistance.

Effect of hyperthermia on the expression of multidrug resistance markers in adriamycin-resistant human gastric cancer cell line SGC-7901/ADM

AIM: To observe the effect of hyperthermia at 43 ℃ on the expression of multidrug resistance-related markers, MDR1, MRP, and LRP in adriamycin (ADM)-resistant human gastric cancer cell line SGC-7901/ADM, and to determine the possible mechanisms underlying the reversal effect of hyperthermia on multidrug resistance.

METHODS: The expression of multidrug resistance molecules MDR1, P-gp, MRP, and LRP in SGC7901/ADM cells treated by hyperthermia at 43°C was assayed by immunocytochemistry, Western blot, and RT-PCR.

RESULTS: The expression of P-gp and MRP was reduced by 31.78% (P = 0.016) and 20.22% (P = 0.037), respectively, in SGC7901/ADM cells exposed to high temperature at 43 ℃ for 60 min, but LRP expression cannot be measured by immunocytochemistry. P-gp expression could not be detected in ADM-sensitive human gastric cancer cell line SGC7901 by Western blot; however, high expression of P-gp was detected in SGC7901/ADM cells. The expression of P-gp could be decreased by high temperature at 43 ℃ in all drug groups, and the expression of P-gp was reduced by 5.65% (P = 0.007), 17.95% (P = 0.021), 11.90% (P = 0.065) in ADM, CDDP and TAX groups, respectively.

CONCLUSION: High temperature at 43 ℃ could partially inhibit the expression of multidrug resistance-related molecules P-gp and MRP in ADM-resistant human gastric cancer cell line SGC7901/ADM.