Project description:This is a Phase 1/2, open-label, first-in-human (FIH) study designed to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary antineoplastic activity of pralsetinib (BLU-667) administered orally in participants with medullary thyroid cancer (MTC), RET-altered NSCLC and other RET-altered solid tumors.
Project description:Metastatic medullary thyroid cancer (MTC) is a currently incurable disease. FDA approved therapies that target RET, a commonly mutated receptor tyrosine kinase in MTC, and other receptor tyrosine kinases, do not result in complete responses and acquired resistance is universal due to “gatekeeper” mutation in Ret or overactivation of alternative signaling pathways. Based on data from human MTCs and a number of murine models, the CDK/RB cell cycle pathway is a potential alternative target for MTC. The objective of this study was to determine if CDKs represent therapeutic targets for MTC and to define mechanisms of activity. We demonstrate that targeting the CDK/RB pathway with Palbociclib (CDK4/6 inhibitor) is not cytotoxic to MTC cells but that Dinaciclib (CDK1/2/5/9 inhibitor) remarkably reduced cell viability and proliferation at low doses in two MTC cell lines accompanied by loss of CDK9 and RET protein and mRNA levels. In human tumors, CDK9 protein was highly expressed and array CGH demonstrated copy number gain in 11/30 analyzed tumors. RNA sequencing demonstrated that RNA polymerase II-dependent transcription was markedly reduced by Dinaciclib, consistent with transcriptional mode of action. Subsequent studies using the CDK7 inhibitor, THZ1, demonstrated high potency vs. the MTC cell lines and marked loss of RET mRNA and protein. In silico analysis, and CHIP-Sequencing using H3K27Ac antibody confirmed that RET is associated with a super-enhancer in RET-mutated MTC cells. In summary, this study reveals a novel mechanism of RET transcription regulation that represents a potentially translatable finding for new therapeutic approaches for RET-mutated MTC.
Project description:Metastatic medullary thyroid cancer (MTC) is a currently incurable disease. FDA approved therapies that target RET, a commonly mutated receptor tyrosine kinase in MTC, and other receptor tyrosine kinases, do not result in complete responses and acquired resistance is universal due to “gatekeeper” mutation in Ret or overactivation of alternative signaling pathways. Based on data from human MTCs and a number of murine models, the CDK/RB cell cycle pathway is a potential alternative target for MTC. The objective of this study was to determine if CDKs represent therapeutic targets for MTC and to define mechanisms of activity. We demonstrate that targeting the CDK/RB pathway with Palbociclib (CDK4/6 inhibitor) is not cytotoxic to MTC cells but that Dinaciclib (CDK1/2/5/9 inhibitor) remarkably reduced cell viability and proliferation at low doses in two MTC cell lines accompanied by loss of CDK9 and RET protein and mRNA levels. In human tumors, CDK9 protein was highly expressed and array CGH demonstrated copy number gain in 11/30 analyzed tumors. RNA sequencing demonstrated that RNA polymerase II-dependent transcription was markedly reduced by Dinaciclib, consistent with transcriptional mode of action. Subsequent studies using the CDK7 inhibitor, THZ1, demonstrated high potency vs. the MTC cell lines and marked loss of RET mRNA and protein. In silico analysis, and CHIP-Sequencing using H3K27Ac antibody confirmed that RET is associated with a super-enhancer in RET-mutated MTC cells. In summary, this study reveals a novel mechanism of RET transcription regulation that represents a potentially translatable finding for new therapeutic approaches for RET-mutated MTC.
Project description:RET is overexpressed in breast cancer cell lines resistant to combined CDK4/6i and endocrine therapy. siRNA-mediated knockdown of RET was performed to identify main pathways altered upon RET-knockdown. We used microarrays to detail the global programme of gene expression following RET knockdown in 2 cell models resistant to combined CDK4/6 inhibitor palbociclib and fulvestrant (MPFR and TPFR). MPFR-ret and TPFR-ret were compared to MPFR-ctrl and TPFR-ctrl, respectively. The gene expression analysis revealed a significant number of genes altered in the knockdown (ret) vs. ctrl
Project description:Hereditary endocrine neoplasias, including phaeochromocytoma/paraganglioma (PPGL) and medullary thyroid cancer (MTC), are caused by autosomal dominant mutations in a multitude of familial cancer genes. A common feature of these diseases is the presentation of multiple primary tumours or multifocal disease representing independent tumour clones that have arisen from the same initiating genetic lesion but have undergone independent clonal evolution. Such tumours provide a unique opportunity to discover common co-operative changes required for tumorigenesis while controlling for the genetic background of the individual. We performed an in-depth genomic analysis of synchronous and metachronous tumours from five patients harbouring germline mutations in the genes SDHB, RET and MAX. Using whole exome sequencing and high-density SNP-arrays we analyzed between two and four primary tumours from each patient. Furthermore, we applied multi-regional sampling to assess intra-tumoral heterogeneity and clonal evolution in two cases involving PPGL and MTC, respectively. Heterogeneous patterns of genomic change existed between synchronous or metachronous tumours with evidence of branching evolution. We observed striking examples of evolutionary convergence involving the same rare somatic copy-number events in synchronous primary PPGL. Convergent events also occurred during clonal evolution of metastatic MTC. These observations suggest that genetic or epigenetic changes acquired early within precursor cells, or pre-existing within the genetic background of the individual, create contingencies that determine the evolutionary trajectory of the tumour.
Project description:Increased treatment of metastatic castration resistant prostate cancer (mCRPC) with second-generation anti-androgen therapies (ADT) has coincided with a greater incidence of lethal, aggressive variant prostate cancer (AVPC) tumors that have lost androgen receptor (AR) signaling. AVPC tumors may also express neuroendocrine markers, termed neuroendocrine prostate cancer (NEPC). Recent evidence suggests kinase signaling may be an important driver of NEPC. To identify targetable kinases in NEPC, we performed global phosphoproteomics comparing AR-negative to AR-positive prostate cancer cell lines and identified multiple altered signaling pathways, including enrichment of RET kinase activity in the AR-negative cell lines. Clinical NEPC and NEPC patient derived xenografts displayed upregulated RET transcript and RET pathway activity. Pharmacologically inhibiting RET kinase in NEPC models dramatically reduced tumor growth and cell viability in mouse and human NEPC models. Our results suggest that targeting RET in NEPC tumors with high RET expression may be a novel treatment option.
Project description:Increased treatment of metastatic castration resistant prostate cancer (mCRPC) with second-generation anti-androgen therapies (ADT) has coincided with a greater incidence of lethal, aggressive variant prostate cancer (AVPC) tumors that have lost androgen receptor (AR) signaling. AVPC tumors may also express neuroendocrine markers, termed neuroendocrine prostate cancer (NEPC). Recent evidence suggests kinase signaling may be an important driver of NEPC. To identify targetable kinases in NEPC, we performed global phosphoproteomics comparing AR-negative to AR-positive prostate cancer cell lines and identified multiple altered signaling pathways, including enrichment of RET kinase activity in the AR-negative cell lines. Clinical NEPC and NEPC patient derived xenografts displayed upregulated RET transcript and RET pathway activity. Pharmacologically inhibiting RET kinase in NEPC models dramatically reduced tumor growth and cell viability in mouse and human NEPC models. Our results suggest that targeting RET in NEPC tumors with high RET expression may be a novel treatment option.
Project description:Medullary thyroid cancer (MTC) accounts for less than 5% of all thyroid cancers, and it is a rare neuroendocrine tumor which derives from calcitonin-secreting thyroid C cells.Given the underlying mechanism involved in MTC remain unclear, the development and the specific pathways of MTC require further investigation.here we employed the application of TMT6plex-based LC-MS/MS to identify and analyze the novel differentially-expressed proteins(DEPs) from MTC patients, To our best knowledge, it is the first study to comprehensively investigate the molecular mechanisms of MTC by proteomics technology from Chinese MTC patients’ tissues, and these DEPs identified in our study will provide a better understanding of the underlying pathophysiology of MTC, as well as may provide potential therapeutic targets for patients with MTC.
Project description:N6-methyladenosine (m6A), the most abundant mRNA modification, is deposited in mammals/drosophila/plants by m6A methyltransferase complexes (MTC) comprising a catalytic subunit and at least five additional proteins. The yeast MTC is critical for meiosis but was known to comprise three proteins, of which two were conserved in mammals. We uncover three novel MTC components (Kar4/Ygl036w-Vir1/Dyn2). All MTC subunits, except for Dyn2, are essential for m6A deposition and have corresponding mammalian orthologs. Nonetheless, the yeast MTC is arranged differently from its mammalian counterpart. The yeast MTC features a mostly mutually stabilizing core comprising Ime4/Mum2/Vir1 and the mRNA binding component Kar4, and an auxiliary hub comprising Slz1/Dyn2. The MTC core subunits when in a complex have both m6A-dependent and m6A-independent functions in meiosis. Kar4 also has a mechanistically separate function from the MTC during mating. Our findings expand the relevance of yeast as a model for unravelling m6A-dependent and independent functions of MTCs.