The myeloma bone marrow microenvironment promotes proliferation of malignant plasma cells and resistance to therapy. Interleukin-6 (IL-6) and downstream JAK/STAT signaling are thought to be central components of these microenvironment-induced phenotypes. In a prior drug repurposing screen, we identified tofacitinib, a pan-JAK inhibitor FDA-approved for rheumatoid arthritis, as an agent that may reverse the tumor-stimulating effects of bone marrow mesenchymal stromal cells. Here, we validated both in vitro, in stromal-responsive human myeloma cell lines, and in vivo, in orthotopic disseminated murine xenograft models of myeloma, that tofacitinib showed both single-agent and combination therapeutic efficacy in myeloma models. Surprisingly, we found that ruxolitinib, an FDA-approved agent targeting JAK1 and JAK2, did not lead to the same anti-myeloma effects. Combination with a novel irreversible JAK3-selective inhibitor also did not enhance ruxolitinib effects. RNA-seq and unbiased phosphoproteomics revealed that marrow stromal cells stimulate a JAK/STAT-mediated proliferative program in myeloma plasma cells, and tofacitinib reversed the large majority of these pro-growth signals. Taken together, our results suggest that tofacitinib specifically reverses the growth-promoting effects of the tumor microenvironment through blocking an IL-6-mediated signaling axis. As tofacitinib is already FDA-approved, these results can be rapidly translated into potential clinical benefits for myeloma patients. Overall design: Single-end 50 bp RNA-seq of MM.1S myeloma cell line either grown alone in monoculture, MM.1S isolated after 24 hr co-culture with immortalized HS5 bone marrow stromal cells, or HS5 bone marrow stromal cells grown alone
Repurposing tofacitinib as an anti-myeloma therapeutic to reverse growth-promoting effects of the bone marrow microenvironment.
Subject
View SamplesIn this study, using a Patient Derived Xenograft (PDX) system established by transplanting primary tumors from pre-metastatic breast cancer patients we demonstrate that development of distant organ metastases correlates with the presence of Bone Marrow Disseminated Tumor Cells (BM DTCs) in the PDX mice. Comparative gene expression analysis of bone marrow (BM) from tumor bearing PDX mice which developed metastatic disease was carried out with BM from non-tumor bearing controls.
Identifying biomarkers of breast cancer micrometastatic disease in bone marrow using a patient-derived xenograft mouse model.
Specimen part
View SamplesA gene expression signature characterizes expression data from breast cancer samples of patients with pathological complete response (pCR) or residual disease (RD) following the neoadjuvant trial.
A gene expression signature that predicts the therapeutic response of the basal-like breast cancer to neoadjuvant chemotherapy.
Sex, Disease stage, Race
View SamplesIn this study, we assess the effect of zoledronic acid on clearance of disseminated tumour cells (DTCs) from the bone marrow in women undergoing neoadjuvant chemotherapy for breast cancer
CXCR4 Protein Epitope Mimetic Antagonist POL5551 Disrupts Metastasis and Enhances Chemotherapy Effect in Triple-Negative Breast Cancer.
Specimen part
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