Id2 promotes the invasive growth of MCF-7 and SKOV-3 cells by a novel mechanism independent of dimerization to basic helix-loop-helix factors

<p>Abstract</p> <p>Background</p> <p>Inhibitor of differentiation 2 (<it>Id2</it>) is a critical factor for cell proliferation and differentiation in normal vertebrate development. Most of the biological function of Id2 has been ascribed to its helix-loop-helix motif. Overexpression of Id2 is frequently observed in various human tumors, but its role for invasion potential in tumor cells is dispute. We aimed to reveal the role of Id2 in invasion potential in poorly invasive and estrogen receptor α (ERα)-positive MCF-7 and SKOV-3 cancer cells.</p> <p>Methods</p> <p>MCF-7 and SKOV-3 cells were stably transfected with the wild-type, degradation-resistant full-length or helix-loop-helix (HLH)-deleted Id2, respectively. Protein levels of Id2 and its mutants and E-cadherin were determined by western blot analysis and mRNA levels of Id2 and its mutants were determined by RT-PCR. The effects of Id2 and its mutants on cell proliferation were determined by [³H]-thymidine incorporation assay and the 3- [4, 5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MTT) dye method. The <it>in vitro </it>invasion potential of cells was evaluated by Transwell assay. Cell motility was assessed by scratch wound assay. The promoter activity of <it>E-cadherin </it>was determined by cotransfection and luciferase assays.</p> <p>Results</p> <p>Ectopic transfection of the wild-type Id2 markedly increased the protein and mRNA expression of <it>Id2 </it>in MCF-7 and SKOV-3 cells; the protein level but not mRNA level was further increased by transfection with the degradation-resistant Id2 form. The ectopic expression of Id2 or its mutants did not alter proliferation of either MCF-7 or SKOV-3 cells. Transfection of the wild-type Id2 significantly induced the invasion potential and migratory capacity of cells, which was further augmented by transfection with the degradation-resistant full-length or HLH-deleted Id2. E-cadherin protein expression and transactivation of the proximal E-cadherin promoter were markedly suppressed by the degradation-resistant full-length or HLH-deleted Id2 but not wild-type Id2. Ectopic expression of E-cadherin in MCF-7 and SKOV-3 cells only partially blunted the invasion potential induced by the degradation-resistant HLH-deleted Id2.</p> <p>Conclusion</p> <p>Overexpression of Id2 in ERα-positive epithelial tumor cells indeed increases the cells' invasive potential through a novel mechanism independent of dimerization to basic helix-loop-helix factors. E-cadherin contributes only in part to Id2-induced cell invasion when Id2 is accumulated to a higher level in some specific cell types.</p

A Retrospective Analysis of the Impact of Myomectomy on Survival in Uterine Sarcoma.

Laparoscopic myomectomy is a minimally invasive, conservative surgical approach commonly used for the treatment of uterine fibroids. However, there is a lack of effective means to distinguish the nature of uterine tumors prior to surgery. The impact of fibroid morcellation during laparoscopic surgery on the dissemination of cancerous uterine fibroids and long-term survival of patients has gained increasing attention. A retrospective cohort study was conducted to analyze the impact of different surgical approaches on recurrence-free survival (RFS) and overall survival (OS) in patients with a postoperative pathological diagnosis of uterine sarcoma at a single medical center. Patients who underwent the first surgery for uterine fibroids (confined to the uterus) and had a postoperative pathological diagnosis of uterine sarcoma were selected in the Chinese PLA General Hospital from January 2005 to January 2014. Based on the use of fibroid morcellation, the subjects were divided into fibroid morcellation (FM) and total hysterectomy (TH, non-morcellation) groups. Follow-up outcomes, including RFS and OS times, were observed. In total, 59 patients were included, with 30 cases in the FM group and 29 cases in the TH group. There were no significant differences in RFS and OS time between the two groups (RFS: P = 0.16, OS: P = 0.09). Multivariate correlation analysis showed that the impact of a higher grade level on RFS and OS was nearly 2-fold the impact of a lower grade level (RFS: P = 0.04, odds ratio (OR) = 1.97; OS: P = 0.03, OR = 2.29). Intraoperative morcellation, postoperative adjuvant therapy, age, tumor size, FIGO stage, and surgical approach were not risk factors affecting RFS and OS. Fibroid morcellation during laparoscopic surgery (including laparoscopic, transvaginal and transabdominal approaches) had no significant impact on RFS and OS time in patients. However, the 5-year RFS and OS rates were both lower in the FM group than in the TH group. Grade level was a significant risk factor for the prognosis of patients with uterine sarcoma

Statistics of basic clinical data.

<p>Statistics of basic clinical data.</p

Survival curves with FIGO stage I (l-Fibroid morcellation group, 2-Total hysterectomy group).

<p>(A) Recurrence-free survival K-M curves, P = 0.15. (B) Overall survival K-M curves, P = 0.25.</p

Multivariate survival analysis of recurrence-free and overall survival.

<p>Multivariate survival analysis of recurrence-free and overall survival.</p