Expression of connexin 32 and connexin 43 in acute myeloid leukemia and their roles in proliferation

Abstract

Abstract. Connexins (Cxs), a conserved family of transmembrane proteins, function in the organization of cell-cell communicatin via gap junctions in multicellular organisms. However, the role of Cxs in acute myeloid leukemia (AML) is poorly understood. In this study, we investigated the relationship between cell proliferation and expression of connexin 43 (Cx43) and connexin 32 (Cx32) mRNA and proteins in acute myeloid leukemia in vitro. Proliferation was observed using a growth curve and the rate of proliferation was detected by MTT assay in the acute myeloid leukemia cell lines OCI-AML3 and OCIM2. Cell cycle and cell proliferation index were assessed by flow cytometry analysis. The mRNA expression of the gap junction genes Cx43 and Cx32 was detected by RT-PCR. The expression of Cx43 and Cx32 proteins in the cell lines was analyzed by western blot analysis and immunofluorescence. The doubling time of OCI-AML3 and OCIM2 was 48 h and 36 h, respectively. In OCIM2, the percentage of cells in the S phase fraction was 59.47±9.6%, and the proliferation rate was 78.12±8.9%; however, in OCI-AML3, the percentage of cells in the S phase was 24.95±5.8%, and the proliferation rate was 35.21±6.7%. At the mRNA level, both cell lines expressed Cx43 and Cx32, and there was no significant difference in the expression of Cx43 and Cx32 mRNA in the two cell lines. At the protein level, there was a significant difference in the expression of Cx43, but not of Cx32. The proliferation ability of OCIM2 was higher than OCI-AML3, and OCIM2 exhibited higher Cx43 western blot and fluorescence intensities compared with OCI-AML3. The results suggest that a higher expression of Cx43 in AML cells may play a significant role in the proliferation ability.

Connexin 43 reduces susceptibility to sympathetic atrial fibrillation

“…connexin 43 (cx43), a member of the connexins family, is most abundantly expressed in the cardiac muscle (7). cx43 has been demonstrated to serve a role in a number of diseases, including oral squamous cell carcinoma, pancreatic cancer, prostate cancer, acute myeloid leukemia, myocardial edema, vascular restenosis and Parkinson's disease (8)(9)(10)(11)(12)(13)(14)(15)(16)(17). cx43 is primarily a fast, low-resistance pathway that regulates electrical conduction between cardiomyocytes, coordinates mechanical and electrical activities of cardiac muscle and controls the conduction velocity of impulses to ensure that myocardial electromechanical activities are synchronized (18).…”

Multistep Model of Cervical Cancer: Participation of miRNAs and Coding Genes

“…ROBO 1 is repressed by epigenetic changes [ 120 ], however, the mRNA has been detected in SiHa cells [ 102 ]. Connexin 43 is a transmembrane protein that functions in the organization of cell-cell communication via gap junctions in multicellular organisms and is up-regulated in cancer [ 121 , 122 ]. Other studies have demonstrated that LAMB3, a protein preferentially expressed in the basal lamina of the epithelium was over-expressed in cervical cancer, and its expression induced migration and invasion in several cell lines [ 61 , 123 , 124 ].…”

Disruption of gap junctions attenuates acute myeloid leukemia chemoresistance induced by bone marrow mesenchymal stromal cells

“…Weber and Tykocinski have reported that direct contact of leukemic cell lines with clonal human KM-102 stromal cells decreases cell differentiation as a consequence of gap junction interactions [27]. Cx43 and Cx32 are expressed in OCIM2 and OCI-AML3 cell lines and the proliferative capacity of OCIM2 cells is related to the expression level of Cx43, suggesting its role in the regulation of cell proliferation [28]. Reikvam et al have described the expression pattern of five different Cxs (Cx26, Cx32, Cx37, Cx43, and Cx45) in primary AML cells [29], and reported a high expression of Cx43 and Cx45, particularly in the most differentiated stages such as FAB M4 and M5) [30].…”