PTHrP increases xenograft growth and promotes integrin alpha6beta4 expression and Akt activation in colon cancer.
Parathyroid hormone-related protein (PTHrP) is expressed by human colon cancer tissue and cell lines. Expression of PTHrP and phosphatidylinositol 3-kinase (PI3-K) pathway components correlates with the severity of colon carcinoma. Here we observed a positive effect of endogenous PTHrP on LoVo (human colon cancer) cell proliferation, migration, invasion, integrin alpha6 and beta4 expression, and p-Akt levels. There was a direct correlation between PTHrP expression and anchorage-independent cell growth. PTHrP significantly increased xenograft growth; tumors from PTHrP-overexpressing cells showed increased expression of integrins alpha6 and beta4, and PI3-K pathway components. The higher expression of PTHrP in human colon cancer adenocarcinoma vs. normal colonic mucosa was accompanied by increased integrin alpha6 and beta4 levels. Elevated PTHrP expression in colon cancer may thus upregulate integrin alpha6beta4 expression, with consequent PI3-K activation. Targeting PTHrP might result in effective inhibition of tumor growth, migration, and invasion.
Shen
Xiaoli
X
Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA.
Rychahou
Piotr G
PG
Evers
B Mark
BM
Falzon
Miriam
M
D000818:Animals; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D049109:Cell Proliferation; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D039161:Integrin alpha6beta4 / Q000096:biosynthesis*; D008297:Male; D051379:Mice; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009374:Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D044162:Parathyroid Hormone-Related Protein / Q000235:genetics / Q000502:physiology*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D014162:Transfection; D014183:Transplantation, Heterologous; D047368:Tumor Burden
D039161:Integrin alpha6beta4; D044162:Parathyroid Hormone-Related Protein; D034741:RNA, Small Interfering; D051057:Proto-Oncogene Proteins c-akt