fenretinide and Rhabdoid-Tumor

Rhabdoid tumors are highly aggressive malignancies affecting infants and very young children. In many instances these tumors are resistant to conventional type chemotherapy necessitating alternative approaches.. Proliferation assays (MTT), apoptosis (propidium iodide/annexin V) and cell cycle analysis (DAPI), RNA expression microarrays and western blots were used to identify synergism of the HDAC (histone deacetylase) inhibitor SAHA with fenretinide, tamoxifen and doxorubicin in rhabdoidtumor cell lines.. HDAC1 and HDAC2 are overexpressed in primary rhabdoid tumors and rhabdoid tumor cell lines. Targeting HDACs in rhabdoid tumors induces cell cycle arrest and apoptosis. On the other hand HDAC inhibition induces deregulated gene programs (MYCC-, RB program and the stem cell program) in rhabdoid tumors. These programs are in general associated with cell cycle progression. Targeting these activated pro-proliferative genes by combined approaches of HDAC-inhibitors plus fenretinide, which inhibits cyclinD1, exhibit strong synergistic effects on induction of apoptosis. Furthermore, HDAC inhibition sensitizes rhabdoid tumor cell lines to cell death induced by chemotherapy.. Our data demonstrate that HDAC inhibitor treatment in combination with fenretinide or conventional chemotherapy is a promising tool for the treatment of chemoresistant rhabdoid tumors.

Topics: Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Blotting, Western; Cell Line, Tumor; Doxorubicin; Drug Synergism; Fenretinide; Histone Deacetylase Inhibitors; Histone Deacetylases; Humans; Hydroxamic Acids; Oligonucleotide Array Sequence Analysis; Real-Time Polymerase Chain Reaction; Rhabdoid Tumor; Vorinostat

Malignant rhabdoid tumor (MRT) is considered to display multi-phenotypic characteristics but the true origin of this tumor remains unknown. In recent years, the concept of the cancer stem cell (CSC) has drawn great attention. In the present study we investigated six MRT cell lines (TM87-16, STM91-01, TTC642, TTC549, YAM-RTK-1 and TTC1240), for CD133, nestin and Musashi-1 (Msi-1), which are considered to be CSC as well as neural stem cell (NSC) markers, using assays for cell viability and apoptosis, reverse transcriptional polymerase chain reaction (RT-PCR), semi-quantitative PCR and Western blot analysis before and after differentiation-induction with N-(4-hydroxyphenyl) retinamid (4-HPR). Before differentiation-induction with 4-HPR, CD133 was detected in three MRT cell lines, nestin in three cell lines and Msi-1 in five cell lines. In TTC549 after differentiation-induction with 4-HPR, nestin and Msi-1 were down-regulated in a time-dependent manner. Similar down-regulation of Msi-1 was recognized in YAM-RTK-1. In STM91-01, CD133 was gradually down-regulated and Msi-1 was down-regulated after a transient increase. Results from our study indicated that 4-HPR might be effective in some MRTs. Expression of NSC markers showed that some MRTs contain a subpopulation of NSC and down-regulation of NSC markers in MRT cells provides supportive evidence that many MRTs could be considered of neuroectodermal origin.

Topics: Animals; Antineoplastic Agents; Apoptosis; Biomarkers; Cell Culture Techniques; Cell Differentiation; Cell Line, Tumor; Cell Survival; Female; Fenretinide; Gene Expression Regulation, Neoplastic; Humans; Infant; Male; Mice; Mice, Nude; Neurons; Rhabdoid Tumor; Stem Cells; Xenograft Model Antitumor Assays

Rhabdoid tumors (RTs) are aggressive pediatric malignancies with poor prognosis that arise due to loss of the hSNF5/INI1 tumor suppressor. Molecular studies indicate that cyclin D1, a downstream effector of INI1 is up regulated in RT, and is essential for this tumor formation. Previously we demonstrated that 4-HPR, a synthetic retinoid that targets Cyclin D1, is a potential chemotherapeutic agent for RT. To facilitate further chemical development of this retinoid, and to determine its active moiety, we synthesized small chemical libraries of 4-HPR and tested their cytotoxic effect on RT cells. We synthesized 4-HPR (1) and the derivatives (5a-5n) starting from retinoic acid. First, retinoic acid was converted to acid chloride derivatives, then in the presence of DMF, base, and aniline derivatives, we synthesized the corresponding 4-hydroxy phenyl amine derivatives (5a-5n). This procedure gave 70-90% yield. Then, the 4-HPR derivatives were tested for their ability to inhibit RT cells using an in vitro cell survival assay. We found that the 4-hydroxy group at para-position is essential for cytotoxic activity against RT cells. Furthermore, we identified a few derivatives of 4-HPR with higher cytotoxic potencies than 4-HPR. In addition, we demonstrate that either chloro, fluoro or iodo derivatives at meta-position of phenyl ring retain the cytotoxic activity. Interestingly, substitution of iodo-moiety at meta-position (5j) substantially increased the efficacy (IC(50) approximately 3muM, Fig. 1D). These results indicate that chemical modification of 4-HPR may result in derivatives with increased therapeutic potential for RTs and that halogen substituted 4-HPR that retain the activity can be synthesized for further therapeutic and diagnostic use.

Topics: Antineoplastic Agents; Apoptosis; Cell Proliferation; Cell Survival; Chemistry, Pharmaceutical; Chlorides; Drug Design; Drug Screening Assays, Antitumor; Fenretinide; Humans; Inhibitory Concentration 50; Models, Chemical; Molecular Conformation; Rhabdoid Tumor; Tretinoin

Rhabdoid tumors (RTs) are an extremely aggressive pediatric malignancy that results from loss of the INI1/hSNF5 tumor suppressor gene. Loss of INI1 results in aberrant expression of Cyclin D1, which supports rhabdoid tumorigenesis and survival. 4-HPR, a synthetic retinoid that down-modulates Cyclin D1, has shown promise in treating various tumors including RTs. In this study, we have generated a chemical library of peptidomimetic derivatives of 4-HPR in an attempt to create a more biologically active compound for use as a therapeutic agent against RTs and other tumors. We have synthesized novel peptidomimetic compound by substituting alkene backbone with a ring structure that retains the biological activity in cell culture models of rhabdoid tumors. We further identified derivative of peptidomimetic compound (11d, IC(50) approximately 3 microM) with approximately five times higher potency than 4-HPR (1, IC(50) approximately 15 microM) based on a survival assay against rhabdoid tumor cells. These studies indicate that peptidomimetic derivatives that retain the cytotoxic activity are promising novel chemotherapeutic agents against RTs and other tumors.

Topics: Alkenes; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Chemistry, Pharmaceutical; Cyclin D1; Drug Design; Fenretinide; Humans; Inhibitory Concentration 50; Models, Chemical; Models, Statistical; Peptides; Rhabdoid Tumor

Rhabdoid tumors (RTs) are aggressive and currently incurable pediatric malignancies. INI1/hSNF5 is a tumor suppressor biallelically inactivated in RTs. Our previous studies have indicated that cyclin D1 is a key downstream target of INI1/hSNF5 and genesis and/or survival of RTs in vivo is critically dependent on the presence of cyclin D1. In this report, we have tested the hypothesis that therapeutic targeting of cyclin D1 is an effective means of treating RTs. We found that RNA interference of cyclin D1 in rhabdoid cells was sufficient to induce G1 arrest and apoptosis. Furthermore, we found that pharmacological intervention with low micromolar concentrations of N-(4-hydroxyphenyl)retinamide (4-HPR), which downmodulates cyclin D1, induced G1 arrest and apoptosis in rhabdoid cell lines. 4-HPR in combination with 4-hydroxy-tamoxifen (4OH-Tam), synergistically inhibited survival as well as anchorage-dependent and -independent growth of rhabdoid cells and caused synergistic induction of cell cycle arrest and apoptosis. 4-HPR and tamoxifen exhibited synergistic growth inhibition of RTs in xenograft models in vivo. The effects of combination of drugs were correlated to the depletion of cyclin D1 levels both in in vitro and in vivo tumor models. These results demonstrate that 4-HPR and tamoxifen are effective chemotherapeutic agents for RTs. We propose that downmodulation of cyclin D1 is a novel and effective therapeutic strategy for RTs.

Topics: Animals; Cell Proliferation; Chromosomal Proteins, Non-Histone; Cyclin D1; DNA-Binding Proteins; Drug Synergism; Fenretinide; Humans; Mice; Rhabdoid Tumor; RNA, Small Interfering; SMARCB1 Protein; Tamoxifen; Transcription Factors