Construction of shRNA-Bmi-1 plasmid and its effect on proliferation of ECA109 cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To explore the role of Bmi-1 gene in the proliferation of squamous carcinoma cells and whether the silencing Bmi-1 can inhibit the growth of squamous cell carcinomas cells.</p><p><b>METHODS</b>The expressions of Bmi-1 in primary cultured Fibroblasts, karatinocyte cell line Hacat,squamous carcinoma cell line A431, and ECA109 were detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis. Recombinant plasmid inserted with Bmi-1 gene short hairpin RNA (shRNA) expression vector PGPU6/GFP/Neo-shBmi-1 was constructed and transfected into ECA109 cells with control set. After transfection for 48 and 72 hours,the mRNA and protein levels of Bmi-1 were examined with RT-PCR and Western blot analysis, respectively. The proliferation of the ECA109 cells was evaluated by MTT method and flow cytometry.</p><p><b>RESULTS</b>Bmi-1 was highly expressed in A431 and ECA109 cells than in Fibroblast cells and Hacat cells. The mRNA and protein expressions of Bmi-1 were significantly silenced in ECA109 cells after recombinant expression vector PGPU6/GFP/Neo-shBmi-1 transfection (P<0.05). Compared with the control groups,the proliferation of ECA109 transfected with PGPU6/GFP/Neo-shBmi-1 was significantly inhibited (P<0.05), and cells in G1 phase increased while in S phase decreased (P<0.05).</p><p><b>CONCLUSIONS</b>Bmi-1 is involved in the proliferation of squamous carcinoma cells. After the silencing of Bmi-1 expression,the proliferation ECA109 cells is suppressed due to the altered cell cycle.</p>

Expression of integrin beta1 in squamous cell carcinoma / 中国医学科学院学报

<p><b>OBJECTIVE</b>To study the expression of integrin beta1 in squamous cell carcinoma (SCC) and explore the relationship between stem cell marker and SCC.</p><p><b>METHODS</b>The expressions of integrin beta1 in SCC tissues and SCC cell strain A431 were detected with immunohistochemical methods and cell staining method. The differentiation of SCC cells were induced with all-trans-retinoic acid (ATRA). The changes of integrin beta1 levels before and after induction were detected with RT-PCR.</p><p><b>RESULTS</b>In highly differentiated SCC tissues, integrin beta1 was constantly expressed in the basal-like cells in the edge of tumor; some cells inside arranged as island also showed positive integrin beta1 expression. In poorly differentiated SCC tissues, island-like integrin beta1-positive cells remarkably increased and distributed in a diffuse way. In SCC A431 cells, integrin beta1 was expressed unevenly in tumor cells. After treatment by ATRA, level of integrin beta1 mRNA in A431 cells significantly decreased compared with untreated control (P < 0.05), and the ratios between the intensity values of integrin beta1 to beta-actin were 0.071 +/- 0.025 and 0.029 +/- 0.018 at 24 h and 48 h, respectively, whereas in controls were 0.148 +/- 0.027 and 0.136 +/- 0.011 (P < 0.05).</p><p><b>CONCLUSIONS</b>Integrin beta1 is heterogeneously expressed in both SCC tissues and SCC A431 cells. The expression of Integrin beta1 decreases when the differentiation level of tumor cells increase, indicating that integrin beta1 is closely related with the initiation of SCC and potential cancer stem cells in SCC.</p>

Localization and differentiation of hair follicle stem cells / 中国医学科学院学报

<p><b>OBJECTIVE</b>To identify the localization of hair follicles stem cell (HFSC) in different stages of hair and explore the differentiating capacity of HFSC into epidermis in vitro.</p><p><b>METHODS</b>HFSC were detected by K19 immunostaining in normal human skin. Then, the isolated HFSC through enzyme digestion were seeded on dermal equivalent (DE) and cultured between the air-liquid interfaces for 14 days. Skin-equivalents was harvested and used for evaluation.</p><p><b>RESULTS</b>HFSC mainly located in outer root sheet in hair follicle and human anagen hair follicles containing two distinct reservoirs for K19-positive cells located in the bulge and bulb of the follicle. These two reservoirs fused in line of outer root sheets during the catagen-telogen transition phase and individualized again in the newly forming anagen hair follicle. Based on DE, growing HFSC built a multilayered and confined epidermis.</p><p><b>CONCLUSION</b>HFSC located in outer root sheets can promote hair cycle and differentiate into epidermis in vitro.</p>