Loss of 4.1N in epithelial ovarian cancer results in EMT and matrix-detached cell death resistance

Epithelial ovarian cancer (EOC) is one of the leading causes of death from gynecologic cancers and peritoneal dissemination is the major cause of death in patients with EOC. Although the loss of 4.1N is associated with increased risk of malignancy, its association with EOC remains unclear. To explore the underlying mechanism of the loss of 4.1N in constitutive activation of epithelial-mesenchymal transition (EMT) and matrix-detached cell death resistance, we investigated samples from 268 formalin-fixed EOC tissues and performed various in vitro and in vivo assays. We report that the loss of 4.1N correlated with progress in clinical stage, as well as poor survival in EOC patients. The loss of 4.1N induces EMT in adherent EOC cells and its expression inhibits anoikis resistance and EMT by directly binding and accelerating the degradation of 14-3-3 in suspension EOC cells. Furthermore, the loss of 4.1N could increase the rate of entosis, which aggravates cell death resistance in suspension EOC cells. Moreover, xenograft tumors in nude mice also show that the loss of 4.1N can aggravate peritoneal dissemination of EOC cells. Single-agent and combination therapy with a ROCK inhibitor and a 14-3-3 antagonist can reduce tumor spread to varying degrees. Our results not only define the vital role of 4.1N loss in inducing EMT, anoikis resistance, and entosis-induced cell death resistance in EOC, but also suggest that individual or combined application of 4.1N, 14-3-3 antagonists, and entosis inhibitors may be a promising therapeutic approach for the treatment of EOC.

Expression of cytoskeletal binding protein 4. 1N in Ewing's sarcoma and its clinical significance / 临床与实验病理学杂志

Purpose To investigate the expression of cy-toskeletal protein 4. 1N in Ewing's sarcoma and the correlation with cell proliferation as well as clinicopathological characteris-tics. Methods Immunohistochemical EnVision two-step stai- ning was used to detect the expression of 4. 1N in 52 Ewing's sarcoma cases, which 47 cases of them were performed to detect the expression of Ki-67. The relationship between the expression of 4. 1N and Ki-67, and the correlation with the pathological fea- tures including prognosis were analyzed. Results The positive expression of 4. 1N was found in 35% (18/52) of Ewing's sar-coma. Lower frequency of 4. 1N strong expression (1. 9% , 1/52) was detected in the cohort. Ki-67 labeling index in Ewing's sarcoma varied from 3% to 85% . 4. 1N expression displayed a negative correlation with Ki-67 index ( P ＜0. 05). Among the follow-up of 27 cases, Kaplan-Meier survival analysis suggested that patients with 4. 1N-negative had shorter survival period than patients with 4. 1N positive expression (P ＜0. 05). However, the expression of 4. 1N was not statistically correlated with sex, age, tumor's localization and metastasis. Conclusion 4. 1N mainly showed negative or lower expression in Ewing's sarcoma and was related to cell proliferation index Ki-67, which implied a potential function in regulating proliferation in Ewing's sarcoma. 4. 1N expression has potentially predictive value in outcome of E-wing's sarcoma.

Effect of 4 . 1N gene transfection on biological characteristics of human lung cancer cell line ;A549 / 肿瘤研究与临床

Objective To investigate the effects of 4.1N expression in lung cancer A549 cell line on cell proliferation, invasion and migration. Methods A549 cells were cultured in vitro and transfected with lipofectamine 2000 mediation. Three groups were employed: transfection with pEGFP-4.1N plasmid, pEGFP vector plasmid, and blank control, respectively. The mRNA and protein expression differences of 4.1N was examined by semi-quantitative RT-PCR and Western blot in every group after 48 h. The proliferation capability was determined by MTT assay. Invasion capability was evaluated by scratches, adhesion experiments and Transwell chamber model. Results After the transfection, the expression of 4.1N mRNA and protein in pEGFP-4.1N plasmid transfection group was significantly enhanced (P<0.05). The proliferation capability of A549 cells descended extremely (P<0.05). The migration and invasion capability of A549 cells in vitro decreased substantially (P<0.05). Conclusions Transfected with 4.1N gene can significantly increases the expression levels of 4.1N mRNA and protein in A549 cells which are highly metastatic in human. Cell behavior in vitro studies showed that 4.1N gene can inhibit the proliferation, adhesion, invasion and migration of A549 cells, which plays an important role in the metastasis of lung cancer and it may become a molecular marker for metastasis of lung cancer.