Laminin-1-derived scrambled peptide AG73T disaggregates laminin-1-induced ovarian cancer cell spheroids and improves the efficacy of cisplatin.

Abstract

We found previously that the laminin-1-derived synthetic peptide AG73 (LQVQLSIR) promoted ovarian cancer cell metastasis in vivo. We have now studied the role of this metastasis-promoting peptide in vitro using TAC3 ovarian cancer cells, which display anchorage-independent growth and form multicellular spheroids. Our goal is to better understand how this peptide can regulate metastasis in vivo. We found that the exogenous addition of either laminin-1 or peptide AG73 stimulated the formation and growth of the spheroids. Western blot analysis indicated that laminin-1 enhanced the expression of integrin beta1, and that AG73 peptide enhanced expression of syndecan-1 and downstream effectors, including mitogen-activated protein kinase (MAPK) and extracellular signal-related kinase (ERK), and also phosphatidylinositol (PI)-3 kinase/AKT activity signaling. The soluble peptide AG73T, which is a scramble peptide of AG73, was able to disaggregate the laminin-1-induced spheroids. Furthermore, the disaggregated cells were twice as sensitive to cisplatin as the intact spheroids. The AG73T peptide in the presence of laminin-1 suppressed expression of integrin beta1 and its downstream effectors, including MAPK/ERK and PI3/AKT activity signaling. The MEK inhibitor U0126 reduced TAC3 cell growth more effectively in the presence of both laminin-1 and AG73T than in the presence of laminin-1 alone. Inhibition of the PI3-K cascade with LY294002 was also more effective in the presence of laminin-1 and AG73T. The increased sensitivity to cisplatin in the presence of AG73T may be due to the greater bioavailability of the drug to the free-floating cells over the spheroids. These findings suggest a novel function of AG73T in ovarian cancer and help to define mechanisms important in ovarian cancer spheroid formation and spread.

• Authors: Yoshio Yoshida, Tetsuji Kurokawa, Yukiko Nishikawa, Makoto Orisa, Hynda K Kleinman, Fumikazu Kotsuji
• Journal: International journal of oncology (Int J Oncol) Vol. 32 Issue 3 Pg. 673-81 (Mar 2008) ISSN: 1019-6439 [Print] Greece
• PMID: 18292945 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• AG73T peptide
• Antineoplastic Agents
• Laminin
• Peptide Fragments
• laminin 1
• Cisplatin

Topics

• Antineoplastic Agents (pharmacology)
• Cell Aggregation (drug effects)
• Cell Proliferation (drug effects)
• Cisplatin (pharmacology)
• Dose-Response Relationship, Drug
• Drug Evaluation, Preclinical
• Drug Resistance, Neoplasm (drug effects)
• Drug Synergism
• Female
• Humans
• Laminin (antagonists & inhibitors, chemistry, pharmacology)
• Ovarian Neoplasms (pathology)
• Peptide Fragments (chemistry, pharmacology)
• Sequence Homology, Amino Acid
• Signal Transduction (drug effects)
• Spheroids, Cellular (drug effects, pathology)
• Treatment Outcome
• Tumor Cells, Cultured