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

Camptothecin (CPT) was conjugated to the N-terminal of a somatostatin analog (SSA) directly via a carbamate group and a basic N-terminal linking motif, D-Lys-D-Tyr-Lys-D-Tyr-D-Lys. This new CPT-SSA conjugate termed JF-10-81 was evaluated as a receptor-specific delivery system for its anti-invasive and anti-angiogenic activities. It was found that, in addition to blocking migration and invasion of highly invasive prostate cancer PC-3 cells, this conjugate also inhibited in vitro capillary-like tube formation of endothelial cells and in vivo angiogenesis in C57B1/6N female mice. JF-10-81 was found to block PC-3 cell attachment to various extracellular matrix components, mainly to vitronectin, the ligand of cell surface receptors integrin alphaVbeta3 and alphaVbeta5. Additionally, JF-10-81 reduced expression of integrins alphaVbeta3 and alphaVbeta5 on PC-3 cell surfaces, without effects on beta1 or any alphabeta1 heterodimers. This conjugate also inactivated phosphorylation of protein kinase B (PKB/Akt), down-regulated the expression of latent matrix metalloproteinase (MMP) -2 and MMP-9, but had little effect on MMP-3/-10. Meanwhile, membrane type-1 matrix metalloproteinase (MT1-MMP) and the tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) were not detectable in PC-3 cells. alphaVbeta3/alphaVbeta5 and MMP-2/-9 are known to be highly expressed in many tumor cells and play an important role in tumor progression. Our results support that this conjugate could possibly inhibit prostate cancer PC-3 cell invasion through a signaling pathway involving PI3K/Akt, alphaVbeta3/alphaVbeta5 and MMP-2/-9, and this SSA could be used as an efficient vector to deliver CPT or other cytotoxic agents to target sites for cancer therapy.
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PMID:A conjugate of camptothecin and a somatostatin analog against prostate cancer cell invasion via a possible signaling pathway involving PI3K/Akt, alphaVbeta3/alphaVbeta5 and MMP-2/-9. 1664 5

Peptide conjugates containing somatostatin (SST) cyclic analogs as a targeting moiety are able to deliver chemotherapeutic agents specifically to cancer cells expressing SST receptors (SSTRs), and hence increasing their local efficacy while limiting the peripheral toxicity. Here, we report on the synthesis and biochemical characterization of new SSTR-specific anticancer peptide conjugates, with different anticancer payloads acting through different oncogenic mechanisms to evaluate their biological activities and to provide a comparative study of their drug release profiles. The SSTR2-specific backbone cyclic peptide 3207-86 was chosen for the synthesis of a variety of novel anticancer drug conjugates with a broad drug release capabilities. The N-terminus of 3207-86 was equipped with GABA to generate free amino group available for the conjugation of chlorambucil, Camptothecin (CPT), Combretastatin 4A, ABT-751, and Amonafide through the formation of various biodegradable bonds. The chemo- and biostability/drug release of all the synthetic compounds was investigated at various pHs and in the presence of mouse liver homogenate, respectively. Their selective cytotoxic effect was evaluated on several human cancer cell lines that overexpress SSTR2. Compared with the free drugs, our peptide-drug conjugates exhibited considerable cytotoxic effect on cancer cell lines versus low SSTR2-expressed human embryonic kidney cells. Functional versatility of the conjugates was reflected in the variability of their drug release profiles, whereas the conserved sequence of a selective binding to the SSTR2 likely preserved their binding to the receptor and consequently their favorable toxicity toward targeted cancer cells.
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PMID:Synthesis, drug release, and biological evaluation of new anticancer drug-bioconjugates containing somatostatin backbone cyclic analog as a targeting moiety. 2605 65

Pancreatic cancer poorly responds to available drugs, and finding novel approaches to target this cancer type is of high significance. Here, based on a common property of pancreatic cancer cells to express somatostatin receptors (SSTR), we designed drug conjugates with novel somatostatin-derived cyclic peptides (SSTp) with broad selectivity towards SSTR types to facilitate drug targeting of the pancreatic cancer cells specifically. Uptake of our newly designed SSTps was facilitated by SSTRs expressed in the pancreatic cancers, including SSTR2, SSTR3, SSTR4 and SSTR5. Three major drugs were conjugated to our best SSTps that served as delivery vehicles, including Camptothecin (CPT), Combretastatin-4A (COMB) and Azatoxin (AZA). All designed drug conjugates demonstrated penetration to pancreatic cancer cell lines, and significant toxicity towards them. Furthermore, the drug conjugates specifically accumulated in tumors in the animal xenograft model, though some accumulation was also seen in kidney. Overall these findings lay the basis for development of novel drug series that could target the fatal pancreatic cancer.
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PMID:New somatostatin-drug conjugates for effective targeting pancreatic cancer. 3001 14