Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The MDM2 protein is known to be overexpressed in some sarcomas including rhabdomyosarcoma. However, the extent to which the MDM2 protein influences sensitivity to chemotherapeutic drugs is unclear. We have analysed this further using stable transfection of the mdm2 gene into 4 well-characterised human paediatric rhabdomyosarcoma cell lines. Transfection with the mdm2 gene resulted in increased levels of the MDM2 protein in all the cell lines. In 2 of the lines, SCMC and RD, the mdm2 gene caused between 2-fold and 61-fold increase in resistance to vincristine, etoposide and doxorubicin but not to cisplatin. In these lines there was an increase in expression of the mdr-1 gene which encodes P-glycoprotein, but not the mrp1 gene which encodes the multidrug resistance protein (MRP). The resistance was reversible using the MDR modulator PSC833, confirming the presence of P-glycoprotein. We conclude that MDM2 overexpression may be a mechanism by which multidrug resistance is regulated in some rhabdomyosarcomas.
 ...
PMID:High levels of the MDM2 oncogene in paediatric rhabdomyosarcoma cell lines may confer multidrug resistance. 1174 97

MDM2 is an oncoprotein best characterized for its role in the inactivation and degradation of the p53 tumor suppressor. However, MDM2 has many other binding partners and its p53-independent role in the regulation of cell growth and survival appears to be extremely complex. This report describes the expression of MDM2 in two rhabdomyosarcoma cell lines, both expressing a mutant p53 gene. Expression of MDM2 in Rh30 cells enhanced cell growth whereas expression of MDM2 in RD cells suppressed their growth and enhanced the rate of spontaneous apoptosis. The mechanism for these opposite phenotypes was demonstrated to be due to differential effects on the NFkappaB pathway. Previously MDM2 has been shown to activate NFkappaB through activation of transcription of the p65RelA subunit. In Rh30 cells MDM2 acted similarly to previously described, thereby promoting growth of Rh30 cells. In untreated RD cells p65RelA was constitutively overexpressed resulting in activation of the NFkappaB pathway. Expression of MDM2 in RD cells transcriptionally repressed p65RelA and suppressed NFkappaB activity, resulting in a reduced growth rate and enhanced apoptosis. The MDM2-sensitive region of the p65 promoter was localized to a 225 bp fragment to which MDM2 protein was shown to bind. The observation that MDM2 induces apoptosis under certain circumstances may help to explain the apparently surprising clinical studies that have shown that MDM2 expression in tumors is often associated with a favorable prognosis.
 ...
PMID:MDM2 displays differential activities dependent upon the activation status of NFkappaB. 1793 75

The GLI1 and MDM2 genes are amplified or exhibit copy number gains in rhabdomyosarcoma (RMS). Here, we used immunohistochemistry to determine the relationships between GLI1 and MDM2 protein expression and several clinicopathological variables of RMS. GLI1 and MDM2-positivity rates were 61.36% and 13.64%, respectively. GLI1 expression correlated with presence of the PAX3-FOXO1 fusion gene (P=0.040) and lymph node metastasis (P=0.034), and a significant association was found between GLI1 expression and overall survival (OS) (P=0.008). However, there was no association between MDM2 expression and any of the clinicopathological parameters or OS. Thus, GLI1 may be a biomarker of poor prognosis in RMS patients, and could itself be a therapeutic target. This contrasts with the apparent lack of clinical importance of MDM2 in RMS pathology, at least in the cohorts we examined.
...
PMID:GLI1 expression is an important prognostic factor that contributes to the poor prognosis of rhabdomyosarcoma. 2654 16