ABSTRACT
BACKGROUND: Rhabdomyosarcoma (RMS) is the most frequent sporadic soft tissue sarcoma of childhood and adolescence. The overall 5-year survival rate for patients with RMS is 70% with the use of surgery, radiation, and chemotherapy. Novel therapeutic approaches are necessary to improve on these outcomes particularly among the more aggressive alveolar RMS (ARMS) and late stages of disease, where 5-year survival is less than 20%. Retinoids have been successfully used in the treatment of acute promyelocytic leukemia (APML) and neuroblastoma. PURPOSE: However, analysis of retinoids as a differentiating agent for RMS has been incomplete. This work examined the ability of retinoic acid (RA) to promote differentiation of RMS cell lines by examining the expression of myogenic proteins in five RMS cell lines in response to All-trans Retinoic Acid (ATRA) or 9-cis retinoic acid (CRA). RESULTS: Analysis of growth curves indicates that both retinoids suppress cell growth of Rh4 and Rh28. RD cells only responded to-CRA whereas Rh30 and Rh18 did not respond. Following treatment with ATRA FACS analysis showed an altered cell cycle with the same pattern as the growth curves. ATRA altered cellular morphology of two cell lines, Rh4 and Rh28, and induced Troponin T expression in these cells suggesting a differentiating effect. CONCLUSIONS: These studies suggest that retinoids are effective inducers of growth arrest and differentiation in some RMS cell lines, and offer a basis for further in vivo testing in mice of ATRA as a potential approach to ARMS treatment.
Subject(s)
Cell Differentiation/drug effects , Rhabdomyosarcoma/drug therapy , Tretinoin/pharmacology , Tumor Suppressor Protein p53/genetics , Alitretinoin , Antineoplastic Agents/pharmacology , Blotting, Western , Cell Line, Tumor , Cell Proliferation/drug effects , Ethanol/pharmacology , Flow Cytometry/methods , Gene Expression Regulation, Neoplastic/genetics , Humans , Immunohistochemistry , Mutation , Rhabdomyosarcoma/genetics , Rhabdomyosarcoma/pathology , Sensitivity and Specificity , Troponin T/analysis , Tumor Cells, CulturedABSTRACT
Multiple early-onset tumors, frequently associated with germ line TP53 mutations characterize the Li-Fraumeni familial cancer syndrome (LFS). LFS-like (LFS-L) families have lower rates of germ line TP53 alteration and do not meet the strict definition of LFS. This study examined 7 LFS cell lines and 30 LFS and 36 LFS-L primary leukocyte samples for mutations in the proapoptotic p53-regulated gene BAX. No germ line BAX mutations were found. A known BAX polymorphism was observed, yet there was no correlation between polymorphism frequency and TP53 status in either LFS or LFS-L. In summary, alterations of BAX are not responsible for cancers in TP53 wild-type LFS or LFS-L families.
