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

Pediatric alveolar rhabdomyosarcoma is characterized by a chromosomal translocation that fuses parts of the PAX3 and FKHR genes. PAX3 codes for a transcriptional regulator that controls developmental programs, and FKHR codes for a forkhead-winged helix protein, also a likely transcription factor. The PAX3-FKHR fusion product retains the DNA binding domains of the PAX3 protein and the putative activator domain of the FKHR protein. The PAX3-FKHR protein has been shown to function as a transcriptional activator. Using the RCAS retroviral vector, we have introduced the PAX3-FKHR gene into chicken embryo fibroblasts. Expression of the PAX3-FKHR protein in these cells leads to transformation: the cells become enlarged, grow tightly packed and in multiple layers, and acquire the ability for anchorage-independent growth. This cellular transformation in vitro will facilitate studies on the mechanism of PAX3-FKHR-induced oncogenesis.
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PMID:The hybrid PAX3-FKHR fusion protein of alveolar rhabdomyosarcoma transforms fibroblasts in culture. 879 Apr 12

A number of drugs developed against cancer-specific molecular targets have been shown to offer survival benefits alone or in combination with standard treatments, especially for those cases in which tumor pathogenesis is dominated by a single molecular abnormality. One example for such a tumor type is alveolar rhabdomyosarcoma (aRMS), which is characterized by a specific translocation creating the oncogenic PAX3/FKHR transcription factor, believed to be the molecular basis of the disease. Recently, we were able to show that the small molecule inhibitor PKC412 (midostaurin) shows strong antitumor activity against aRMS by reducing the transcriptional activity of PAX3/FKHR. In this study, we screened for combination strategies that are superior to PKC412-only treatment and found that the combination of PKC412 with histone deacetylase inhibitors like valproic acid (VPA) synergistically induced apoptosis resulting in suppressed aRMS tumor growth in vivo. We provide evidence that the antitumor effect on combination treatment is achieved by VPA-induced reactivation of p21, which is downregulated in aRMS cells by destabilization of the transcriptional regulator EGR1 by PAX3/FKHR. Our study highlights a possible mechanism behind the increased efficacy and indicates that different arms of PAX3/FKHR oncogenicity can be exploited therapeutically by the specific combination of drugs to increase their therapeutic potential.
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PMID:p21 Downregulation is an important component of PAX3/FKHR oncogenicity and its reactivation by HDAC inhibitors enhances combination treatment. 2045 78

Rhabdomyosarcoma, the most common soft tissue malignancy of childhood, is a morphologically variable tumor defined by its phenotype of skeletal muscle differentiation. The diagnosis of rhabdomyosarcoma often relies in part on the identification of myogenic gene expression using immunohistochemical or molecular techniques. However, these techniques show imperfect sensitivity and specificity, particularly in scant tissue biopsies. Here, we expand the toolkit for rhabdomyosarcoma diagnosis by studying the expression of PAX7, a transcriptional regulator of mammalian muscle progenitor cells implicated in the pathogenesis of rhabdomyosarcoma. Immunohistochemical analysis of tissue microarrays using a monoclonal anti-PAX7 antibody was used to characterize PAX7 expression in 25 non-neoplastic tissues, 109 rhabdomyosarcomas, and 697 small round blue cell or other soft tissue tumors. Among non-neoplastic tissues, PAX7 was specifically expressed in adult muscle progenitor cells (satellite cells). In embryonal rhabdomyosarcoma, PAX7 expression was positive in 52 of 63 cases (83%), negative in 9 of 63 cases (14%), and focal in 2 of 63 cases (3%). PAX7-positive embryonal rhabdomyosarcoma cases included several showing focal or negative myogenin expression. PAX7 expression in alveolar rhabdomyosarcoma was positive in 6 of 31 cases (19%), negative in 14 of 31 cases (45%), and focal in 11 of 31 cases (36%). In addition, PAX7 was expressed in 5 of 7 pleomorphic rhabdomyosarcomas (71%) and 6 of 8 spindle cell rhabdomyosarcomas (75%). Among histologic mimics, only Ewing sarcoma showed PAX7 expression (7/7 cases, 100%). In contrast, expression of PAX7 was not seen in the large majority (688/690, 99.7%) of examined cases of other soft tissue tumors, small round blue cell neoplasms, and leukemias/lymphomas. In summary, immunohistochemical analysis of PAX7 expression may be a useful diagnostic tool in the assessment of skeletal muscle differentiation in human tumors.
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PMID:PAX7 Expression in Rhabdomyosarcoma, Related Soft Tissue Tumors, and Small Round Blue Cell Neoplasms. 2752 98

PAX7 is a paired-box transcription factor that is required for the developmental specification of adult skeletal muscle progenitors in mice. We previously demonstrated PAX7 expression as a marker of skeletal muscle differentiation in rhabdomyosarcoma. Here, using analyses of published whole-genome gene expression microarray data, we identify PAX7 as a gene with significantly increased expression in Ewing sarcoma in comparison to CIC-DUX4 round cell sarcoma. Analysis of PAX7 in a large cohort of 103 Ewing sarcoma cases by immunohistochemistry revealed expression in 99.0% of cases (102/103). PAX7 expression was noted in cases demonstrating three distinct Ewing sarcoma EWSR1 translocations involving FLI1, ERG, and NFATc2. No PAX7 expression was observed in any of 27 cases of CIC-DUX4 sarcoma by immunohistochemistry (0%; 0/27). Exploring the mechanism of PAX7 expression in Ewing sarcoma using curated RNA- and ChIP-sequencing data, we demonstrate that the EWSR1 fusion protein is required for PAX7 expression in Ewing sarcoma and identify a candidate EWSR1-FLI1-bound PAX7 enhancer that coincides with both a consensus GGAA repeat-containing binding site and a peak of regulatory H3K27 acetylation. Taken together, our findings provide mechanistic support for the utility of PAX7 immunohistochemistry in the diagnosis of Ewing sarcoma, while linking this sarcoma of uncertain histogenesis to a key transcriptional regulator of mammalian muscle progenitor cells.
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PMID:EWSR1 fusion proteins mediate PAX7 expression in Ewing sarcoma. 2998 54

Rhabdomyosarcoma (RMS) is a common malignancy of soft tissue, subclassified as alveolar (ARMS), pleomorphic (PRMS), spindle cell/sclerosing (SRMS), and embryonal (ERMS) types. The Yes-associated protein (YAP) is a member of the Hippo pathway and a transcriptional regulator that controls cell proliferation. We have studied the immunohistochemical expression of YAP in different RMSs, arranged in tissue microarray (TMA) and whole slide formats. Pertinent clinical data including patient age, gender, tumor location, and clinical stage were collected. Out of 96 TMA cases, 30 cases (31%) were pleomorphic, 27 (28%) were embryonal, 24 (25%) alveolar, and 15 (16%) spindle cell. Positive nuclear YAP staining was seen in the PRMS (17/30, 56.7%), SRMS (7/15, 46.7%), ERMS (19/27 or 70%), and less in ARMS (37.5%). YAP nuclear staining was significantly more prevalent in ERMS than ARMS ( p=0.02). Of the 41 whole slide cases, nuclear staining was detected in all ARMS but was restricted in distribution to <30% of the cells, in contrast to ERMS and SRMS, which had diffuse or >30% staining. These results highlight the role of YAP in RMS tumorigenesis, a fact that can be useful in engineering targeted therapy. Restricted nuclear YAP staining (<30% of cells) may be of value in the diagnosis of ARMS.
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PMID:Potential Value of YAP Staining in Rhabdomyosarcoma. 2959 30

Rhabdomyosarcoma is subclassified by the presence or absence of a recurrent chromosome translocation that fuses the FOXO1 and PAX3 or PAX7 genes. The fusion protein (FOXO1-PAX3/7) retains both binding domains and becomes a novel and potent transcriptional regulator in rhabdomyosarcoma subtypes. Many studies have characterized and integrated genomic, transcriptomic, and epigenomic differences among rhabdomyosarcoma subtypes that contain the FOXO1-PAX3/7 gene fusion and those that do not; however, few investigations have investigated how gene co-expression networks are altered by FOXO1-PAX3/7. Although transcriptional data offer insight into one level of functional regulation, gene co-expression networks have the potential to identify biological interactions and pathways that underpin oncogenesis and tumorigenicity. Thus, we examined gene co-expression networks for rhabdomyosarcoma that were FOXO1-PAX3 positive, FOXO1-PAX7 positive, or fusion negative. Gene co-expression networks were mined using local maximum Quasi-Clique Merger (lmQCM) and analyzed for co-expression differences among rhabdomyosarcoma subtypes. This analysis observed 41 co-expression modules that were shared between fusion negative and positive samples, of which 17/41 showed significant up- or down-regulation in respect to fusion status. Fusion positive and negative rhabdomyosarcoma showed differing modularity of co-expression networks with fusion negative (n = 109) having significantly more individual modules than fusion positive (n = 53). Subsequent analysis of gene co-expression networks for PAX3 and PAX7 type fusions observed 17/53 were differentially expressed between the two subtypes. Gene list enrichment analysis found that gene ontology terms were poorly matched with biological processes and molecular function for most co-expression modules identified in this study; however, co-expressed modules were frequently localized to cytobands on chromosomes 8 and 11. Overall, we observed substantial restructuring of co-expression networks relative to fusion status and fusion type in rhabdomyosarcoma and identified previously overlooked genes and pathways that may be targeted in this pernicious disease.
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PMID:Gene Co-Expression Networks Restructured Gene Fusion in Rhabdomyosarcoma Cancers. 3148 Mar 61