Identification and characterization of a novel CXC chemokine in xenograft tumor induced by mas-overexpressing cells.

Overexpressions of G protein-coupled receptor (GPCR) with elevated downstream signaling events have been reported in various tumors. However, the cellular mechanism that GPCR overexpression leads to tumor formation is largely unknown. The orphan GPCR mas was originally isolated from a human epidermoid carcinoma. In vivo studies of mas-overexpressing cells suggested that xenograft tumor formation was positively correlated with the levels of mas expression. Histochemical analysis indicated that xenograft tumor consisted of mas-transfected and stromal cells. Biochemical analyses revealed that cells overexpressing mas exhibited significantly increased anchorage-independent growth, whereas there was no significant difference in cell proliferation in comparison with empty vector-transfected control cells. Expression profiling using mRNA differential display and Northern analysis indicated an elevated expression of GRO and a novel CXC chemokines, tumor-induced factor (TIF), in mas-transfected cells and xenograft tumor. Bacterially expressed recombinant TIF was found to act as a neutrophil chemoattractant in a chemotactic assay. These results suggest that mas overexpression enables anchorage-independent growth of transformed cells, and interplays of secreted chemokines with stromal cells modulate xenograft tumor formation. Importantly, a novel CXC chemokine, TIF, was identified in the xenograft tumor tissues.

[Effect of shRNA-mediated survivin gene silencing on apoptosis and proliferation of leukemia cell line].

OBJECTIVE: To transfect a short hairpin RNA (shRNA) against survivin gene into human T lymphoblastic leukemia cell line Jurkat, and to explore the effects on apoptosis and proliferation of transfected cells. METHODS: The survivin-shRNA expression vector were constructed and transfected into Jurkat cells. Expression of survivin mRNA and protein were assessed by RT-PCR and Western blot analysis respectively. Apoptosis index of transfected Jurkat cells was quantified by flow cytometry. The potential of cell proliferation was described by cell growth curves. RESULTS: In survivin-shRNA transfected Jurkat cells, survivin mRNA levels were significantly reduced by 66.67% ( transient transfection) and 60.69% ( stable transfection) respectively, compared with that in control-shRNA treated group and PBS treated group (P < 0.05); and the levels of survivin protein were significantly reduced by 63.41% (transient transfection) and 60.18% (stable transfection), compared with that in the two control groups (P < 0.05). Apoptosis index was significantly increased during both transient and stable transfection, respectively [(22. 41 +/- 2.83)% and (20.73 +/- 2.56)% (P < 0.05)]. Survivin-shRNA also inhibited the proliferation of Jurkat cells. CONCLUSIONS: Vector-based survivin-shRNA can effectively reduce the expression of survivin gene, induce apoptosis

Knockdown of survivin gene by vector-based short hairpin RNA technique induces apoptosis and growth inhibition in Burkitt's lymphoma Raji cell line.

Survivin is the smallest member of mammalian IAP (inhibitor of apoptosis) family. It is ubiquitous during embryonic development but is not expressed in normal post-natal tissues, except the thymus, colonic epithelial cells and CD34+ hematopoietic stem cells. However, its expression is upregulated during neoplastic transformation in both solid organ and hematological malignancies, including leukemia and lymphoma. In this study, we used RNA interference with short hairpin RNA (shRNA) technique to inhibit survivin expression in a Burkitt's lymphoma cell line Raji and validated its effects on apoptosis and cell proliferation. A survivin-shRNA expression vector were constructed and introduced into Raji cells. Expression of survivin mRNA and protein was assessed by RT-PCR and western blot analysis. Apoptosis index of transfected cells was quantified by flow cytometry and cell proliferation was enumerated by trypan blue exclusion. In Raji cells treated with survivin-shRNA expression vector, survivin mRNA levels were significantly reduced by 67.14% (transient transfection) and 64.28% (stable transfection) respectively, compared with control-shRNA treated group and PBS treated group (p<0.05). The levels of survivin protein were significantly reduced by 62.50% (transient transfection) and 60.93% (stable transfection), compared with the two control groups (p<0.05). Apoptosis index was significantly increased during transient transfection and stable transfection, respectively 31.20+/-2.45% and 29.40+/-1.72% (p<0.05). Survivin-shRNA inhibited the proliferation of Raji cells of stable transfection. In conclusion, the vector-based survivin-shRNA can effectively reduce the expression of survivin gene and induce apoptosis and growth inhibition of transfected Raji cells. We suggest that survivin can be regarded as an ideal target for new anticancer intervention of NHL.

[Effect of survivin antisense mRNA transfection on the growth and chemotherapy sensitivity of lymphoma cells].

OBJECTIVE: To study the effect of transfecting survivin antisense mRNA on growth and chemotherapy sensitivity of lymphoma cells. METHODS: Eukaryotic expression plasmid pcDNA3. 1-antisense (As) survivin was constructed and transfected into Jurkat T lymphoblastic lymphoma cell lines with high expression survivin mRNA by use of lipofectmine gene transfer technique. Expression of survivin mRNA and protein were detected by reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemical and Western blot. The effect of transfecting survivin antisense mRNA on the growth of Jurkat cell lines was monitored by population doubling time (PDT) and Apoptotic indexes (AI). The morphologic features were observed in transfected cells by light and electric microscopes. MTT assay was used to analyze the response of transfected cells to CTX and MTX. RESULTS: Compared with the control cells, the expression of survivin mRNA and protein were reduced after transfected pcDNA3. 1-Assurvivin 48 h, 5 w and 6 w, PDT (52 h) was prolonged. Apoptotic indexes were higher in transfected antisense survivin mRNA cells [20.2% (48 h)], 6.2% (5 w) and 6.8% (6 w) than control ones [2.1%, 1.3% (48 h)] and [1.3% (5 w) and 1.0% (6 w)]. The cells grow slowly and the dead cells increase and some swelling and apoptotic cells were observed in transfected pcDNA3. 1-Assurvivin groups by invert, light and electric microscopes. The Jurkat cell line of transfected pcDNA3. 1-Assurvivin had higher sensitivity to CTX and MTX. The rate of inhibition was higher in transfected group. There is a significant difference between the transfected group and untransfected one, P < 0.05. CONCLUSIONS: The result indicated that survivin gene was very important for growth of Jurkat cells. To inhibit the expression of survivin will be significant in therapy of T lymphoblastic lymphoma. Survivin gene might be a target of therapy.