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

BACKGROUND: Secretion 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. RESULTS: This study documents the molecular presence of human chorionic gonadotropin beta subunit in uterine cervix cancer tissues and investigates a novel technique to reduce hCGbeta 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 hCGbeta mRNA. Three different 5' end-mutated U1 snRNA expression plasmids were tested, each targeting a different sequence in the hCGbeta mRNA, and we found each one blocked the expression of hCGbeta in HeLa cells, a cervix carcinoma cell line, as shown by immunohistochemistry and qRT-PCR. Reduction of hCGbeta levels resulted in a significantly increased apoptosis rate with almost 90% of cells transfected with modified anti-hCGbeta U1 snRNAs showing morphological changes characteristic of the apoptotic process. CONCLUSION: These data suggest that human chorionic gonadotropin beta subunit may act as a tumor growth-stimulating factor

ACTH-induced ultrastructural changes in the zona fasciculata of the hamster adrenal cortex. Are intraadrenal thrombi regulators of corticosteroid secretion?

Correlated stereological and functional studies were performed on the effect of massive ACTH doses on adrenal cortex of the female hamster. ACTH resulted in a marked increase in adrenal gland weight at day 6 of treatment followed by a drop at day 9. Stereology showed significant enlargement of the zona fasciculata (ZF) cells with the highest value at day 6 and subsequent drop at day 9 of treatment. This hypertrophy was due to a notable increase in the volume of mitochondrial, SER, Golgi apparatus and lipid droplet compartments. Cortisol secretion by adrenal slices and homogenates was also highest at day 6 of ACTH administration and notably lower at day 9. At day 6 of ACTH treatment in outer ZF thrombi were seen. In their vicinity the subendothelial space was dilated and endothelial cells dissociated from the basa1 lamina. Numerous erythrocytes were also visible among dissociated ZF cells. At day 9 of experiment in outer part of ZF numerous spaces devoid of parenchymal cells appeared. The earlier authors considered the «empty spaces» or «holes» in hyperstimulated adrenal cortex as-a sign of holocrine secretion of steroid hormones. The present findings enable us to introduce a new hypothesis on the development of these spaces. In our opinion in hyperstimulated adrenal cortex numerous thrombi may be formed leading thus to the degeneration of adrenocortical cells. Thus, the appearance of the aempty spaces» or «holes» in the gland is not connected with the holocrine secretion but with the regulation of the number of secretory cells in adrenal cortex by the thrombi-dependent mechanism. A similar mechanism may also be responsible for the remodelling of the gland after its enlargement due to ACTH administration

Rod outer segment membrane guanylate cyclase type 1 (ROS-GC1) calcium-modulated transduction system in the sperm

OBJECTIVE: Evaluation of the presence of a Ca(2+)-regulated membrane guanylate cyclase signal transudation system in the spermatozoa. DESIGN: Experimental study. SETTING: Research university laboratory. PATIENT(S): Human sperm obtained from healthy donors who met the criteria of the World Health Organization for normozoospermia and bovine semen collected from bulls of proven fertility. INTERVENTION(S): Radioimmunoassay and immunohistochemistry of human and bovine spermatozoa. MAIN OUTCOME MEASURE(S): The membrane guanylate cyclase activity and the presence of membrane guanylate cyclase transduction machinery components in the spermatozoa. RESULT(S): The identity of a Ca(2+)-modulated membrane guanylate cyclase transduction machinery in human and bovine spermatozoa has been documented. The machinery is both inhibited and stimulated within nanomolar to semimicromolar range of free Ca(2+). The transduction component of this machinery is the rod outer segment membrane guanylate cyclase type 1 (ROS-GC1). The enzyme coexists with three Ca(2+)-dependent modulators: guanylate cyclase activating protein type 1 (GCAP1), S100B and neurocalcin delta. ROS-GC1 and its modulators are present in the heads and tails of both species' spermatozoa. CONCLUSION(S): The coexpression of ROS-GC1 and its activators in spermatozoa suggests that the Ca(2+)-modulated ROS-GC1 transduction system may be a part of the fertilization machinery