No abstract

Uncontrolled cell proliferation and inhibition of apoptosis are considered to be vital for cancer initiation, maintenance, infiltration, metastasis and recurrence after anti-cancer therapy. Here we report the generation of a novel cell line by reprogramming child foreskin fibroblast with the full length apoptosis inhibitor gene PIWIL2. The fibroblasts transfected with PIWIL2 expressed the stem cell markers OCT-4, NANOG, SOX-2, KLF-4 and C-MYC; endoderm marker AFP and GATA6; mesoderm markers ACTA2 and BRACHYURY; and ectoderm markers NESTIN and TUBB3. The karyotype was found to be hyperdiploid. The PIWIL2 transfected fibroblast cells grew into tumorous masses within 5 weeks of subcutaneous injection into adult nude mice. Although the injected cell expressed markers for all three germlines, ectoderm, mesoderm, and endoderm, they did not form teratomas in vivo. This study indicates that the PIWIL2 gene could play a key role in cancer induction and maintenance. This method for generating induced tumorigenic cells (ITGC) provides a new research tool to study oncogenesis that in turn may lead to a better understanding of cancer etiology and the development of novel anti-cancer therapies.

This study explored the expression of connexin 43 (Cx43) in the testes of prepubertal SpragueDawley (SD) rats following in utero flutamide (Flu) exposure. Connexins constitute the major protein type in gap junctions. Connexin 43, the most prominent connexin family member expressed by testes, is localized at the base of seminiferous tubules in humans and rodents, and may be involved in fertility. Flutamide was injected subcutaneously into pregnant SD rats on gestational days 12-21 (25 mg/kg/day). Immunohistochemistry, Western blotting, and real-time PCR was used to investigate the distribution and the expression of Cx43 protein and mRNA in the testis on postnatal day 20 (PD20). Following Flu-exposure, Cx43 was observed between Sertoli cells in the seminiferous tubules. On PD20, no Cx43 protein was expressed by the spermatogonial cell layer of the seminiferous tubules in the controls, but was observed in the Flu-exposed group. Western blotting showed that Cx43 was expressed at significantly lower levels in Flu-exposed testes than controls on PD20 (p50.001). On PD20, levels of Cx43 mRNA in undescended Flu-exposed testes were significantly lower than in controls (p50.05) and descended Flu-exposed testes (p50.01). After Flu-exposure in the rat embryonic period, Cx43 mRNA and protein expression were downregulated, and its distribution in the seminiferous tubules was abnormal.