Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P61278 (somatostatin)
 22,083 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We report a series of new in vitro and in vivo data proving the selective antitumor activity of our somatostatin structural derivative, TT-232. In vitro, it inhibited the proliferation of 20 different human tumor cell lines in the range of 50-95% and induced a very strong apoptosis. In vivo TT-232 was effective on transplanted animal tumors (Colon 26, B16 melanoma, and S180 sarcoma) and on human tumor xenografts. Treatment of MDA-MB-231 human breast cancer xenografted in mice with low submaximal doses of TT-232 [0.25 and 0.5 mg/kg of body weight (b.w.)] caused an average 80% decrease in the tumor volume resulting in 30% tumor-free animals surviving for longer than 200 days. Treatment of prostate tumor (PC-3) xenografted animals with 20 mg/kg of b.w. of TT-232 for 3 weeks resulted in 60% decrease in tumor volume and 100% survival even after 60 days, while 80% of nontreated animals perished. We have demonstrated that TT-232 did not bind to the membrane preparation of rat pituitary and cortex and had no antisecretory activity. TT-232 was not toxic at a dose of 120 mg/kg of b.w. in mice. Long-term incubation (24 h) of tumor cells with TT-232 caused significant inhibition of tyrosine kinases in good correlation with the apoptosis-inducing effect. The level of p53 or KU86 did not change following TT-232 treatment, suggesting a p53-independent apoptotic effect. Preincubation of human breast cancer cells (MDA-MB-453) with TT-232 for 2 h decreased the growth factor receptor autophosphorylation. All of these data suggest that TT-232 is a promising and selective antitumor agent.
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PMID:A tumor-selective somatostatin analog (TT-232) with strong in vitro and in vivo antitumor activity. 890 13

Somatostatin is a peptide hormone that exerts antisecretory and antiproliferative activities on some human tumors. The Ku70/86 heterodimer acts as regulatory subunit of the DNA dependent protein kinase and its DNA binding activity mediates DNA double strands breaks repair that is crucial to maintain the genetic integrity of the genome. The activation of the heterodimer regulates cell cycle progression and the activity of nuclear transcription factors involved in DNA replication and cell proliferation. Moreover Ku86 behaves as a receptor for the growth inhibitory tetradecapeptide, somatostatin. Herein we report that somatostatin treatment to a colon carcinoma cell line (Caco-2) inhibits cell growth and, at same time, strongly modulates the activation of Ku70/86 heterodimer and the levels of Ku86 in the nucleus by increasing its specific mRNA level. Our findings are consistent with the hypothesis that somatostatin controls cell cycle progression and DNA repair through a new signalling pathway that involves the regulation of Ku86 level and modulates the Ku70/86 activity in the nucleus.
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PMID:The expression and the nuclear activity of the caretaker gene ku86 are modulated by somatostatin. 1520 76

Activation of pro-survival pathways and apoptotic cell death escape are considered hallmarks of oncogenic cell transformation. Tissue microenvironment strongly influences tumorigenesis, redirecting some pathways versus a persisting pro-survival state. Here, we report evidence on the role of interleukin 6 (IL-6) in affecting pro-survival pathways in colon cancer progression, modulating the expression and the molecular interactions among the pro-apoptotic factor Bax, the DNA repair proteins Ku70/86 and Clusterin isoforms. In human colorectal carcinomas (n = 50) at different stages of disease, we found an increased IL-6 production, the loss of Ku86 and Clusterin 50-55 kDa pro-apoptotic isoform. Conversely, we observed the overexpression of Bax and the 40 kDa prosurvival sClusterin (sCLU) isoform. Bax co-localized with Ku70 that was found atypically expressed in the cytoplasm of advanced stage colon cancers (Dukes'C-D; n = 22). IL-6 treatment of a colon cancer cell line, Caco-2, modulated the expression of genes involved in tumor invasion and apoptosis, as observed by microarrays. In particular, IL-6 downmodulated Bax expression at mRNA level. Concomitantly, IL-6 exposure influenced Bax also at protein level acting on the Bax-Ku70-sCLU physical interactions in the cytoplasm, by affecting the Ku70 acetylation and phosphorylation state, thus leading to the inhibition of Bax pro-apoptotic activity. In addition, we found that IL-6 treatment induced a significant downregulation of Ku86 and a strong increase of sCLU, confirming tumor biopsies data. In contrast Somatostatin treatment of Caco-2 cells was able to restore apoptosis, demonstrating that Ku70-Bax-CLU interactions could be dynamically modulated. Hence, IL-6 could favor tumor expansion, promoting cell survival and apoptosis escape throughout the different stages of tumor evolution. Uncovering the molecular mechanisms of action of these factors may offer strategies for selectively manipulate the cancer cells sensitivity to therapy.
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PMID:Interleukin-6 affects cell death escaping mechanisms acting on Bax-Ku70-Clusterin interactions in human colon cancer progression. 1917 10