Reduction of human chorionic gonadotropin beta subunit expression by modified U1 snRNA caused apoptosis in cervical cancer cells

Abstract

BackgroundSecretion of human chorionic gonadotropin, especially its beta subunit by malignant trophoblastic tumors and varieties of tumors of different origin is now well documented; however the role of hCG in tumorogenesis is still unknown.ResultsThis study documents the molecular presence of human chorionic gonadotropin beta subunit in uterine cervix cancer tissues and investigates a novel technique to reduce hCGβ levels based on expression of a modified U1 snRNA as a method to study the hormone's role in biology of human cervical cancer cells cultured in vitro. The property of U1 snRNA to block the accumulation of specific RNA transcript when it binds to its donor sequence within the 3' terminal exon was used. The first 10 nucleotides of the human U1 snRNA gene, which normally binds to the 5'ss in pre-mRNA were replaced by a sequence complementary to a 10-nt segment in the terminal exon of the hCGβ mRNA. Three different 5' end-mutated U1 snRNA expression plasmids were tested, each targeting a different sequence in the hCGβ mRNA, and we found each one blocked the expression of hCGβ in HeLa cells, a cervix carcinoma cell line, as shown by immunohistochemistry and qRT-PCR. Reduction of hCGβ levels resulted in a significantly increased apoptosis rate with almost 90% of cells transfected with modified anti-hCGβ U1 snRNAs showing morphological changes characteristic of the apoptotic process.ConclusionThese data suggest that human chorionic gonadotropin beta subunit may act as a tumor growth-stimulating factor.

Transgenesis-Mediated Reproductive Dysfunction and Tumorigenesis: Effects of Immunological Neutralization

“…On the basis of previous reports [11]–[13] as well as unpublished data on the growth-promoting effects of βhCG on tumor cells, whether serum derived from TG animals could promote the growth of tumor cells was ascertained. LLC, COLO 205 and ChaGO cells demonstrated enhanced viability when incubated with TG serum but not with serum obtained from WT mice.…”

“…hCG is now know to be made by variety of cancers of non-trophoblastic origin, for example those of the colon, prostate, bladder, breast and lung. βhCG secreted by tumor cells exhibits growth factor-like properties [11]–[13]. The presence of membrane-associated βhCG has been shown to correlate with the metastatic potential of tumor cells [35] and expression of the molecule is associated with poor prognosis [1]–[3].…”

“…In view of the demonstrated growth-promoting effects of βhCG on tumor cells [11]–[13], sera derived from TG mice, wild-type (WT) mice as well as from immunized TG mice were assessed for effects on tumor cell viability. Since emerging evidence appears to suggest that hCG may also exhibit angiogenic [14] and pro-invasive [15] activity, sera from non-immunized and immunized TG mice were evaluated for the ability to induce the transcription and expression of vascular endothelial growth factor (VEGF), KC (murine IL-8) as well as of matrix mellatoprotease (MMP)-9 from tumor cells.…”

Immunological Approaches Against Human Chorionic Gonadotropin for Control of Fertility and Therapy of Advanced‐Stage Cancers Expressing hCG/Subunits

“…30 Reduction in bhCG subunit expression in cervical cancer cell lines by silencing RNA led to apoptosis of the HeLa cells. 31 Another important action of hCG or its subunits is on promotion of angiogenesis by stimulating the migration and capillary sprout formation of uterine endothelial cells. High levels of hCG and its subunits is associated with high microvessel density in hCG expressing cancers.…”

“…American Journal of Reproductive Immunology 66 (2011)[26][27][28][29][30][31][32][33][34][35][36][37][38][39] …”