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M C Kibbey

Publications and source records attributed to M C Kibbey.

7 recordsLinked to original sources
PubMed1992

Role of the SIKVAV site of laminin in promotion of angiogenesis and tumor growth: an in vivo Matrigel model.

BACKGROUND: Angiogenesis (vascularization) has a critical role in tumor growth and metastasis, and peptides containing the SIKVAV amino acid sequence (Ser-Ile-Lys-Val-Ala-Val) have been shown to stimulate many angiogenic activities in vitro. The use of model systems to identify agents that stimulate or inhibit angiogenesis may lead to the development of new antitumor strategies. PURPOSE: Our purpose was to use an in vivo murine model system to study the angiogenic activity of a synthetic peptide derived from the laminin A protein chain and containing the SIKVAV amino acid sequence. We also examined the ability of the peptide to enhance tumor growth in vivo. METHODS: The SIKVAV-containing peptide was mixed with Matrigel, a reconstituted basement membrane extract used to assay stimulation of angiogenesis. The mixture was subcutaneously injected into C57BL/6 mice. At various times after injection, the Matrigel plug was excised, and angiogenic activity was assessed by histologic examination and immunohistochemical staining with an antibody to the von Willebrand factor (vWF), an endothelium-specific antigen. In other experiments, the mixture of peptide and Matrigel was co-injected with B16F10 murine melanoma cells into C57BL/6 mice, and the resultant tumors were assessed for size and vascularization. RESULTS: When co-injected with Matrigel at doses as low as 10 micrograms, the SIKVAV-containing peptide stimulated angiogenesis fourfold greater than that seen in controls, and maximum angiogenic activity was observed 2 weeks after injection. This peptide was angiogenic in a dose-dependent manner up to a 100-micrograms dose. When co-injected with Matrigel and B16F10 melanoma cells, the peptide enhanced tumor growth by approximately 2.5-fold, and tumor vascularization was significantly increased (P = .027) over that observed after injection with melanoma cells and Matrigel alone. CONCLUSIONS: These data demonstrate that the laminin-derived SIKVAV-containing peptide is angiogenic in a new in vivo model system and can enhance tumor vascularization and growth.

Amino Acid Sequence↗
PubMed1992

The all-D-configuration segment containing the IKVAV sequence of laminin A chain has similar activities to the all-L-peptide in vitro and in vivo.

Laminin is a basement membrane glycoprotein that has diverse biological activities. A sequence on the A chain containing IKVAV (Ile-Lys-Val-Ala-Val) has been shown to promote neurite outgrowth, cell adhesion, and tumor growth and metastasis. Here we have determined the structural requirements of this synthetic peptide for biological activity. Twelve-amino acid-long all-L- (LAM-L) and all-D-peptide (LAM-D) segments as well as an alternating D- and L-amino acid-containing peptide (LAM-DL), which included the IKVAV sequence (residues 2097-2108), were synthesized. Circular dichroism spectral analysis revealed a mirror image conformation of LAM-D and LAM-L with mainly beta-sheet and to a minor extent alpha-helical structure. LAM-DL did not exhibit any significant ordered conformational features. LAM-D and LAM-L showed similar cell attachment activities for rat pheochromocytoma cells (PC12), whereas LAM-DL was inactive. A peptide analog with randomized IKVAV sequence (LAM-RM) was also inactive. A similar trend was observed in competition experiments of the four peptides with laminin in analogous cell attachment assays. In in vivo experiments, both LAM-D and LAM-L were capable of increasing tumor growth when subcutaneously injected into mice with murine melanoma cells B16F10. Results indicate that the conformational status of the IKVAV domain is a contributing factor in determining the biological activity but that there is no strict requirement for a specific chirality. There is a likely sequence specificity to the IKVAV region.

Amino Acid Sequence↗
PubMed1992

Glandular-like morphogenesis of the human submandibular tumor cell line A253 on basement membrane components.

We have studied the interaction of a human tumor cell line, A253, derived from a submandibular gland carcinoma with a differentiation promoting reconstituted basement membrane extract, Matrigel. When cultured on plastic, these cells maintain a flat, cobblestone, epithelial morphology. On Matrigel, A253 cells initially form a honeycomb network of cords of cells which subsequently thickens. With time, these cords of cells become discontinuous and blunted, whereupon multilobular clusters of cells develop. These clusters possess a lumen with polarized, PAS(+) cells containing numerous desmosomes and an abundance of glycogen. Culture of the cells on laminin, the most abundant protein found in Matrigel, also induces this morphologic differentiation. Using synthetic laminin-derived peptides, the biologically active IKVAV-containing site of laminin was most active in attachment assays, as well as in inhibiting glandular-like morphogenesis when added to the media of cells cultured on Matrigel. Antibodies to the cell surface 67- and 32-kDa laminin binding proteins partially inhibited the glandular-like morphogenesis, suggesting that multiple interactions with laminin are likely required for the differentiation process. Our data demonstrate that A253 cells can undergo glandular-like morphogenesis on basement membrane and that laminin appears to be the major initiating factor.

Blotting, Western↗
PubMed1992

Transfection of murine P19S18 embryonal carcinoma cells with the oncogene neu induces an epithelioid phenotype.

An embryonal carcinoma cell line, P19S18, was transfected with the rat oncogene neu to investigate the function of its protein product, p185*, in a multipotential cellular environment. Levels of message for p185* were determined by in situ hybridization analysis and two highly expressing clones, PnnA and PnnB, were isolated. As demonstrated by indirect immunofluorescence and immunoprecipitation, these neu-transfected cells synthesized a full length rat p185*. The transfectants do not resemble typical embryonal carcinoma cells either before or after differentiation is induced by retinoic acid treatment. They are much larger, flatter, "epithelioid" cells. These cells have lost the expression of stage specific embryonic antigen-1 (SSEA-1), but do synthesize and assemble the basement membrane components laminin and fibronectin. These results suggest that expression of the neu oncogene in a multipotential cell line may induce the synthesis of proteins indicative of an epithelioid phenotype due to the presence of p185*.

Animals↗
PubMed1991

Enhanced tumor growth of both primary and established human and murine tumor cells in athymic mice after coinjection with Matrigel.

Previously we found that the reconstituted basement membrane matrix Matrigel, when premixed with human small-cell lung carcinoma cells and injected subcutaneously into athymic mice, permitted tumor growth, whereas cells injected in the absence of Matrigel did not form tumors. In the present study, we examined additional cell types and determined some of the underlying mechanisms involved in the promotion of tumor formation by Matrigel. The tumor cell lines that we studied included transformed mouse Englebreth-Holm-Swarm tumor cells (T-EHS), human submandibular carcinoma A253 cells, mouse melanoma B16F10 cells, human epidermoid carcinoma KB cells, and human primary renal cell carcinoma cells. When coinjected subcutaneously with Matrigel, these cell lines formed rapidly proliferating tumors. Primary biopsy specimens of human colon carcinoma, when dispersed and coinjected with Matrigel, also formed tumors. Only A253, KB, and B16F10 cells formed small tumors in the absence of Martrigel, but a fivefold to tenfold increase in tumor size was observed in the presence of Matrigel. These data demonstrate a useful method for improving the growth of human tumors in athymic mice.

Animals↗
PubMed1991

Basement membrane and the SIKVAV laminin-derived peptide promote tumor growth and metastases.

Laminin, the major glycoprotein component of basement membrane, promotes the malignant phenotype. Cells which are adherent to laminin are more malignant than the non-adherent cells and in certain tumor cells, the number of laminin receptors is positively correlated with malignancy. Laminin also increases collagenase IV activity, an enzyme demonstrated to be critical for tumor spread. A site on laminin, containing the amino acid sequence SIKVAV, has been identified which when injected intravenously with B16F10 melanoma cells, causes an increase in the number of colonies on the surface of the lungs. This peptide does not affect tumor cell arrest in the vasculature or the immune system. It does promote angiogenesis in various in vitro and in vivo models, thereby facilitating tumor cell survival. When a complex mixture of laminin-enriched basement membrane components (Matrigel) is coinjected with tumor cells subcutaneously, tumor incidence and growth increases. Various tumor cell lines and primary isolates, which previously could not form tumors in mice, can be induced to grow rapidly in the presence of Matrigel. Slowly growing tumors or arrested tumors can also be induced to grow more quickly with additional injections of Matrigel. When an SIKVAV-containing synthetic peptide is coinjected with B16F10 tumor cells and Matrigel subcutaneously in mice, larger tumors are formed than that observed with either Matrigel or cells alone. Such studies define the role of laminin in tumor growth and spread and generate new models for studying therapeutic agents. Of particular interest is the ability to grow primary isolates which generally do not grow in mice.

Amino Acid Sequence↗