PLAC8 promotes the autophagic activity and improves the growth priority of human trophoblast cells.

Autophagy plays an important role in the normal development and function of trophoblast cells and is precisely regulated during pregnancy. Dysregulated autophagy contributes to the abnormal proliferation of trophoblasts, which is closely related to the occurrence of pregnancy-related diseases. Placenta specific 8 (PLAC8, Onzin) is a multifaceted protein proven to promote autophagy and potentiate various tumor progression. Its role in trophoblasts remains elusive. In our present study, PLAC8 expression was detected in tissues of first-trimester placentas (n = 5), term placentas (n = 5), choriocarcinoma (n = 5), and placental site trophoblastic tumor (n = 5). PLAC8 expression was increased in gestational neoplasms compared with normal pregnancies. mCherry-EGFP-LC3B reporter and transmission electron microscopy confirmed PLAC8 promoted the autophagic flux of human trophoblast cells. Both gain-of-function and loss-of-function experiments demonstrated PLAC8-regulated autophagy-related genes, including ATG5, ATG12, and Beclin-1. In addition, our data showed that PLAC8 co-localized with p53 and promoted its degradation, and p53 re-expression partially abrogated the PLAC8-induced autophagy activity. Furthermore, the overexpression of PLAC8 promoted cell viability and proliferation, acting as a protective mechanism of trophoblasts against the cytotoxicity of etoposide (VP-16). Such a phenomenon was effectively abrogated by autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ). In conclusion, PLAC8-induced autophagy to promote the proliferation of trophoblasts. This study provided insights into the mechanism of PLAC8-induced autophagy in trophoblasts, which is significant for a wide range of gestational diseases and may contribute to developing novel treatment strategies for trophoblastic diseases.

lnc003875/miR-363/EGR1 regulatory network in the carcinoma -associated fibroblasts controls the angiogenesis of human placental site trophoblastic tumor (PSTT).

The rare gestational trophoblastic neoplasia placental site trophoblastic tumor (PSTT) frequently demonstrates a high degree of vascularization, which may facilitate the tumor metastasis. However, the underlying mechanisms remain largely unknown. In the present study, we found that early growth response 1 (EGR1) was highly expressed in the carcinoma-associated fibroblasts (CAFs) of PSTT tissues. Further data showed that miR-363 down-regulated EGR1 expression whereas long non-coding RNA NONHSAT003875 (lnc003875) up-regulated EGR1 expression in PSTT derived CAFs. lnc003875 exerted no effect on miR-363 expression, but it recovered the decrease of EGR1 caused by miR-363 mimic. The conditioned media from PSTT CAFs treated with miR-363 mimic abrogated the tube formation capacity of human umbilical vein endothelial cells (HUVECs), which can be partially restored by lnc003875 over-expression. Moreover, over-expression of EGR1 promoted the secretion of Angiopoietin-1 (Ang-1) in PSTT derived CAFs and improved the tube formation of HUVECs, which could be effectively abrogated by Ang-1 siRNAs. In vivo vasculogenesis assay demonstrated that lnc003875/EGR1 in PSTT derived CAFs promoted the vasculogenesis of HUVECs in C57BL/6 mice. Collectively, these findings indicated that lnc003875/miR-363/EGR1/Ang-1 in CAFs may be crucial for the angiogenesis of PSTT.

ß-catenin/LIN28B promotes the proliferation of human choriocarcinoma cells via Let-7a repression.

Choriocarcinoma is a rare and malignant trophoblastic tumor. However, the molecular mechanisms by which choriocarcinoma is regulated remain unknown. In the present study, we first elucidated that LIN28B was highly expressed in human choriocarcinoma tissues and choriocarcinoma cell lines. Our data further demonstrated that knockdown of LIN28B by small interfering RNA caused an increase in Let-7a expression in JAR cells. In addition, silencing of LIN28B inhibited IGF2BP1 expression and suppressed cell proliferation capacity, both of which can be markedly restored by Let-7a inhibitor. In contrast, LIN28B over-expression-improved cell proliferation was inhibited by Let-7a mimic. Knockdown of ß-catenin resulted in reduced expression of LIN28B and increased expression of Let-7a. Knockdown of ß-catenin also caused a decrease in cell proliferation, which can be recovered by re-expression of LIN28B or by Let-7a inhibitor. Collectively, our data indicate that ß-catenin/LIN28B/Let-7a pathway may be crucial for the regulation of cell proliferation in human choriocarcinoma cells.

APOBEC3B up-regulation independently predicts ovarian cancer prognosis: a cohort study.

BACKGROUND: Ovarian cancer is a heterogeneous disease with a high degree of genomic instability, pro-/antitumor immunity and inflammation, and remains the most lethal gynecologic cancer worldwide. APOBEC3B, a member of the AID/APOBEC family, is part of the innate immune system which plays a key role in combating exogenous infection especially viral infection. Studies have shown that APOBEC3B expression is elevated in a variety of cancer tissues and cell lines, and plays a prominent role in the genesis and evolution of various cancers. However, the clinical relevance of APOBEC3B in ovarian cancer needs to be further investigated. The current study aimed to evaluate the predictive value of APOBEC3B in ovarian cancer clinical outcome, and to explore possible molecular mechanisms contributing to ovarian cancer progression. METHODS: The expression of APOBEC3B in biopsy tissue specimens from 88 ovarian cancer patients was examined using immunohistochemistry. In addition, ovarian cancer cell lines were transfected with APOBEC3B siRNA or pLenti-APOBEC3B construct. Western blotting and SRB assay were performed to explore the role of APOBEC3B in ovarian cancer. RESULTS: Patients were followed for a median of 74.77 months following the time of surgery. Forty-two patients had died, 5 had relapsed but were still alive at the end of study, and 41 patients remained alive and had no recurrence. Over-expression of APOBEC3B was associated with advanced FIGO stage and elevated CA125 (both p< 0.05). Univariate analysis result showed that histological subtype, FIGO stage, intravascular tumor thrombus, CA125 and APOBEC3B expression were associated with overall survival and disease-free survival of ovarian cancer patients. Multivariate analysis result showed that higher APOBEC3B expression were an independent prognostic factor to predict both worse overall survival (hazard ratio: 5.18, 95% confidence interval: 1.40-11.95, p= 0.003) and disease-free survival (hazard ratio: 4.23, 95% confidence interval: 1.60-11.17, p= 0.004) of ovarian cancer patients. Furthermore, knockdown of APOBEC3B expression in ovarian cancer cells caused an decrease in cell line viability. CONCLUSIONS: APOBEC3B expression is an independent prognostic factor in ovarian cancer patients. Knockdown of APOBEC3B expression affects ovarian cancer viability.

Aberrantly Expressed SALL4 Promotes Cell Proliferation via ß-Catenin/c-Myc Pathway in Human Choriocarcinoma Cells.

Sal-like protein 4 (SALL4) has been proved to play a pivotal role in the development and progression of various cancers. Previous studies showed that SALL4 was highly expressed in human choriocarcinoma tissues. However, the role of SALL4 in the biological behavior of human choriocarcinoma cells remains largely unknown. In this study, we first elucidated that SALL4 was highly expressed in human choriocarcinoma cell line JEG-3 and JAR. Sal-like protein 4 knockdown by small interfering RNA (siRNA) decreased c-Myc expression, whereas SALL4 overexpression by transfection of human pLenti-SALL4 construct promoted c-Myc expression. Further data showed that SALL4 overexpression improved cell proliferation of JEG-3 cells, which can be abrogated by c-Myc siRNA. Moreover, our data showed that SALL4 interact with ß-catenin and SALL4 overexpression promoted the localization of ß-catenin in the nucleus and ß-catenin siRNA abrogated SALL4-induced c-Myc expression in JEG-3 cells. These data indicate that aberrantly expressed SALL4 in human choriocarcinoma cells may promote cell proliferation via ß-catenin/c-Myc pathway, indicating that SALL4 may be potential treatment targets of human choriocarcinoma.