ABSTRACT
@#[Abstract] Objective: To investigate the osteogenic differentiation characteristics of mesenchymal stem cell (MSC) derived from bone marrow in patients with myelodysplastic syndromes (MDS) and its clinical significance. Methods: Bone marrow samples from 30 cases of newly diagnosed untreated MDS patient atAffiliated Hospital of Heibei University were collected for this study. MSCs from MDS patients and normal subjects were isolated and cultured, and morphological characteristics of MSCs were observed in vitro; under proper conditions, MSCs were induced to differentiate into osteoblasts and adipocytes; The formation of calcium nodules at 14th day after osteogenic differentiation was observed by alizarin red staining; mRNA expressions of osteogenic differentiation transcription factors Ostefix and RUNX2 in undifferentiated MSCs, as well as the mRNAexpression of Jagged-1, which involved in the transformation from hematopoietic cells into leukemic cells, were detected by quantitative PCR. Results: The MSCs derived from patients with MDS were characterized with increased cell volume and decreased differentiation potential. Compared with the control group, the expression levels of osteogenic differentiation transcription factors Osterix and RUNX2 were significantly decreased (P < 0.05). Alizarin red staining showed that the content of calcium nodules in MDS group was significantly less than that in the normal control group, while the expression level of Jagged-1 was significantly higher (P < 0.05). Conclusion: MSCs derived from bone marrow of MDS patients showed significant increased cell volume, decreased differentiation potential and elevated Jagged-1 expression; all of these might play important roles in the .hematopoietic failure and progression to acute myeloid leukemia in MDS patients.
ABSTRACT
OBJECTIVE To investigate the underlying mechanism of drug resistance to cisplatin and increasing the sensitivity to therapeutic drugs are key steps towards the improved treatment of patients with ovarian cancer. Gap junction (GJ) and connexin (Cx) are closely related to tumor formation, but the relationship between cisplatin resistance and GJ or Cx are undetermined. METHODS We established the cisplatin-resistant human ovarian cancer cell line A2780-CDDP over an 11-month period, with the concentration of cisplatin gradually increasing from 0.5 g·L-1 to 16 g·L-1. To explore the effect of GJ in the process of cisplatin resistance, we investigated GJ using a parachute dyecoupling assay in A2780- RI(1.2), A2780- RI(1.7), A2780- RI(2.9), A2780- RI(4.3) and A2780- CDDP cells. We further explored whether the Cxs responsible for GJ were related to cisplatin resistance. In A2780- RI(1.2), A2780-RI(1.7), A2780-RI(2.9), A2780-RI(4.3) and A2780-CDDP, we used q-PCR to analyze the levels of Cx43, Cx40, Cx37, and Cx32. To confirm the effect of Cx32 on cisplatin resistance, we knocked down Cx32 in A2780-CDDP cells with siRNA-Cx32. As GJ was decreased whereas Cx32 expression was elevated during the cisplatin resistance process, it drove us to explore the underlying mechanism. To resolve this issue, we extracted membrane-bound and cytoplasmic proteins from A2780 and A2780-CDDP cells. RESULTS Here we showed that cisplatin resistance was correlated to the loss of GJ and the upregulation of Cx32 expression. Enhancing GJ in A2780-CDDP cells could increase the apoptotic response to cisplatin treatment. Furthermore, although Cx32 expression was increased in A2780-CDDP cells, it was more localized to the cytoplasm rather than in the membrane, and knockdown of Cx32 in A2780-CDDP cells sensitized them to cisplatin treatment. CONCLUSION In summary, Cx32 is involved in cisplatin resistance, and cytoplasmic Cx32 plays an important role in chemoresistance.
ABSTRACT
ABSTRACT:OBJECTIVE To investigate the role of connexin proteins (Cx), which form gap junctions (GJ), in progression and chemotherapeutic sensitivity of cervical cancer (CaCx). METHODS We analyze the expression of Cx26, Cx30, Cx32 and Cx43 in human specimens consisting of: Normal cervix (n=78), CaCx FIGO stage Ⅰ (n=148), CaCx FIGO stage Ⅱ (n=165). InCaCx cell lines, Hela- Cx32 (induced expression by doxycycline), C- 33A (endogenously express Cx32) and siHa (transiently transfected plasmid with Cx32), we detected the role of Cx32 against tostreptonigrin/cisplatin-induced apopotosisin presence or absence of functional GJ through using GJ inhibitors or low density cultural.Furtherly, we observed the relativity of Cx32 and EGFR expression in human specimens. Also, we detected the role of EGFR signaling pathway in the process of Cx32 anti-apoptosis through suppressed EGFR expression by inhibitors or siRNA sequences in cell lines. RESULTS We firstly demonstrated the expression of Cx32 was highly upregulated and accumulated in cytoplasm in the CaCx specimens, and the degree of upregulation correlated with advanced FIGO stages. Thus,in three human cervical cell lines, Cx32 was shown to suppress apoptosis when GJ formation is inhibited. No matter in cases of CaCx or cell lines, Cx32 expression was highly correlated with expression of EGFR and the EGFR pathway is an essential component of the Cx32-induced anti-apoptotic effect. CONCLUSION Cx32, traditionally tumor suppressive protein, was shown to be tumor protective against chemotherapy through EGFR pathway in a GJ-independent way.