cyclin-d1 and Rhabdomyosarcoma--Alveolar

A natural isoquinoline alkaloid, berberine, has been known to exhibit anti-tumor activity in various cancer cells

Topics: Antineoplastic Agents; Berberine; Berberine Alkaloids; Cell Line, Tumor; Cell Proliferation; Cyclin D1; Cyclin-Dependent Kinase Inhibitor p57; Drug Evaluation, Preclinical; Drugs, Chinese Herbal; G1 Phase Cell Cycle Checkpoints; Gene Expression; Gene Expression Regulation, Neoplastic; Humans; Ki-67 Antigen; Molecular Conformation; Molecular Docking Simulation; Phellodendron; Rhabdomyosarcoma, Alveolar; Rhabdomyosarcoma, Embryonal

The chromosome translocations generating PAX3-FOXO1 and PAX7-FOXO1 chimeric proteins are the primary hallmarks of the paediatric fusion-positive alveolar subtype of Rhabdomyosarcoma (FP-RMS). Despite the ability of these transcription factors to remodel chromatin landscapes and promote the expression of tumour driver genes, they only inefficiently promote malignant transformation in vivo. The reason for this is unclear. To address this, we developed an in ovo model to follow the response of spinal cord progenitors to PAX-FOXO1s. Our data demonstrate that PAX-FOXO1s, but not wild-type PAX3 or PAX7, trigger the trans-differentiation of neural cells into FP-RMS-like cells with myogenic characteristics. In parallel, PAX-FOXO1s remodel the neural pseudo-stratified epithelium into a cohesive mesenchyme capable of tissue invasion. Surprisingly, expression of PAX-FOXO1s, similar to wild-type PAX3/7, reduce the levels of CDK-CYCLIN activity and increase the fraction of cells in G1. Introduction of CYCLIN D1 or MYCN overcomes this PAX-FOXO1-mediated cell cycle inhibition and promotes tumour growth. Together, our findings reveal a mechanism that can explain the apparent limited oncogenicity of PAX-FOXO1 fusion transcription factors. They are also consistent with certain clinical reports indicative of a neural origin of FP-RMS.

Topics: Animals; Biopsy; Cell Transdifferentiation; Cell Transformation, Neoplastic; Chick Embryo; Child; Cyclin D1; Datasets as Topic; Disease Models, Animal; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Humans; N-Myc Proto-Oncogene Protein; Neoplasm Invasiveness; Neural Stem Cells; Neural Tube; Oncogene Proteins, Fusion; Paired Box Transcription Factors; PAX3 Transcription Factor; PAX7 Transcription Factor; Rhabdomyosarcoma, Alveolar; S Phase

Rhabdomyosarcoma is the most commonly occurring soft-tissue sarcoma in children. Some reports have discussed the altered expression and molecular abnormalities of cell-cycle-regulatory proteins in rhabdomyosarcoma; however, variable frequencies of occurrence have been noted. In the current study, among 72 cases of rhabdomyosarcoma, the authors evaluated for the expression of p53, MDM2, p16, p21/WAF1, p27, cyclin D1, cyclin E, pRb and E2F-1 protein immunohistochemically and assessed for proliferative activities using MIB-1. We also analyzed the mutation of the p53 gene in 45 cases, the amplification of the MDM2 gene in 18 cases and the mutation of the H-ras gene in 29 cases, using formalin-fixed paraffin-embedded materials. Furthermore, we assessed the correlation between clinicopathologic factors and the results of both immunohistochemical and molecular analyses. Alveolar type affected older patients, and it had a significantly higher mitotic rate compared with the embryonal type (P=0.0226). p53 overexpression was detected in 22 (30.6%) of 72 cases, and 10 (22.2%) of 45 cases had p53 gene abnormalities. As for MDM2, its overexpression was found in nine (12.5%) of 72 cases, and three (16.7%) of 18 cases showed MDM2 amplification. A statistically significant association was observed between immunoreaction for MDM2 and p53 overexpression (P=0.0002), and p53 and MDM2 overexpression was significantly correlated with high MIB-1 labeling indices. E2F-1 labeling indices showed a significantly higher score in alveolar type compared with that seen in embryonal type (P=0.0334), but MIB-1 did not. In conclusion, our study suggests that p53 overexpression may be related to tumor progression because tumors with p53 overexpression have a high proliferative activity in the current study. Alveolar type had a significantly higher both mitotic rate and E2F-1 labeling indices when compared with the embryonal type. The current study is the first report of the correlation of E2F-1 with alveolar rhabdomyosarcoma.

Topics: Adolescent; Base Sequence; Cell Cycle Proteins; Child; Cyclin D1; Cyclin E; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p27; DNA Mutational Analysis; DNA-Binding Proteins; DNA, Neoplasm; E2F Transcription Factors; E2F1 Transcription Factor; Exons; Female; Gene Amplification; Gene Expression Regulation, Neoplastic; Humans; Immunohistochemistry; Ki-67 Antigen; Male; Mutation; Nuclear Proteins; Polymerase Chain Reaction; Polymorphism, Single-Stranded Conformational; Proto-Oncogene Proteins; Proto-Oncogene Proteins c-mdm2; Proto-Oncogene Proteins p21(ras); Retinoblastoma Protein; Rhabdomyosarcoma; Rhabdomyosarcoma, Alveolar; Rhabdomyosarcoma, Embryonal; Transcription Factors; Tumor Suppressor Protein p53; Tumor Suppressor Proteins

In this study, we investigated the mRNA level of several genes involved in cell cycle regulation in alveolar (ARMS) and embryonal rhabdomyosarcomas (ERMS). p21(Cip1), Cyclin D1, Cyclin D2, Cyclin D3, CDK2, and CDK4 were evaluated by RT-PCR. All (13 out of 13) ERMS expressed the p21(Cip1) gene compared with only 40% (4 out of 10) of the ARMS. Moreover, the amount of p21(Cip1) mRNA was noticeably higher in the ERMS samples than in the positive ARMS specimens. p27(Kip1) protein were analysed by immunohistochemical and immunoblotting. A noticeable difference was observed, in that ERMS had higher amounts of the cell cycle inhibitor compared with the ARMS. Finally, treatment of two rhabdomyosarcoma cell lines, RH-30 and RD, with butyrate, resulted in complete growth inhibition and in the upregulation of the p21(Cip1) and p27(Kip1) levels. Our results demonstrate that ERMS have a much higher level of p27(Kip1) and p21(Cip1) than the alveolar types, explaining, at least in part, the distinct features and outcomes (i.e. a poor prognosis of the alveolar type) of the two forms of this childhood solid cancer. Moreover, the data on butyrate-treated cell lines suggest that the two genes are potential novel therapeutic targets for the treatment of rhabdomyosarcomas.

Topics: CDC2-CDC28 Kinases; Cell Cycle; Cell Cycle Proteins; Cyclin D1; Cyclin D2; Cyclin D3; Cyclin-Dependent Kinase 2; Cyclin-Dependent Kinase Inhibitor p21; Cyclin-Dependent Kinases; Cyclins; Humans; Immunohistochemistry; Oncogene Protein p21(ras); Protein Serine-Threonine Kinases; Reverse Transcriptase Polymerase Chain Reaction; Rhabdomyosarcoma, Alveolar; Rhabdomyosarcoma, Embryonal; Tumor Cells, Cultured