ABSTRACT
The aim of this article is to study the regulatory feedback loop between β-catenin and IQ motif containing GTPase activating protein 1 (IQGAP1), as well as the effect of this regulation loop in colon cancer cell proliferation. Western blot was used to detect the expression of IQGAP1 and β-catenin after changing their expression respectively by transfection in SW1116 cells. CCK-8 cell proliferation assay was used to detect the effect of IQGAP1 involved in the proliferation of SW1116 cells promoted by β-catenin. The results of Western blot indicated that β-catenin could positively regulate IQGAP1, while IQGAP1 silencing could up-regulate β-catenin, forming a negative feedback loop. The results of CCK-8 showed that IQGAP1 silencing inhibited β-catenin-mediated proliferation in SW1116 cells. In conclusion, our research reveals a negative regulatory feedback loop between β-catenin and IQGAP1 which has a remarkable effect on the proliferation ability of colon cancer cells.
ABSTRACT
Objective: To explore the molecular mechanism of SAM-and SH3-domain containing 1 (SASH1) which serves as a novel tumor suppressor gene to regulate breast cancer metastasis. Methods: The expressions of SASH1, IQ motif-containing GTPase activating protein 1 (IQGAP1) and E-cadherin in breast cancer tissues were analyzed by immunohistochemistry (IHC). The correlation among SASH1, IQGAP1 and E-cadherin, as well as the association of SASH1 and IQGAP1 expressions with the clinical parameters of breast cancer patients were analyzed, respectively. The recombinant plasmids HAIQGAP1-pcDNA3.0 and pEGFP-C3-SASH1 were cloned and transfected into human embryonic kidney HEK-293T cells. The interaction of SASH1 and IQGAP1 was analyzed by immunoprecipitation-Western blotting. Results: In breast cancer tissues, there was a correlation between the expressions of SASH1 and IQGAP1 (P 0.05). The recombinant plasmids HAIQGAP1-pcDNA3.0 and pEGFP-C3-SASH1 were constructed successfully. After these recombinant plasmids were transfected into HEK-293T cells, the interaction between SASH1 and IQGAP1 was found. Conclusion: SASH1 interacts with IQGAP1, and which is closely related to the expression of E-cadherin. Therefore, it is suggested that SASH1 may form a new signaling cascade with IQGAP1 and E-cadherin to regulate breast cancer metastasis.