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Linnet Hartley posted an update 3 days, 12 hours ago
High-dose chemotherapy with melphalan followed by autologous transplantation is a first-line treatment for multiple myeloma. Here, we present preclinical evidence that this treatment may be significantly improved by the addition of exportin 1 inhibitors (XPO1i). The XPO1i selinexor, eltanexor, and KOS-2464 sensitized human multiple myeloma cells to melphalan. Human 8226 and U266 multiple myeloma cell lines and melphalan-resistant cell lines (8226-LR5 and U266-LR6) were highly sensitized to melphalan by XPO1i. Multiple myeloma cells from newly diagnosed and relapsed/refractory multiple myeloma patients were also sensitized by XPO1i to melphalan. In NOD/SCIDγ mice challenged with either parental 8226 or U266 multiple myeloma and melphalan-resistant multiple myeloma tumors, XPO1i/melphalan combination treatments demonstrated stronger synergistic antitumor effects than single-agent melphalan with minimal toxicity. Synergistic cell death resulted from increased XPO1i/melphalan-induced DNA damage in a dose-dependent manner and decreased DNA repair. In addition, repair of melphalan-induced DNA damage was inhibited by selinexor, which decreased melphalan-induced monoubiquitination of FANCD2 in multiple myeloma cells. Knockdown of FANCD2 was found to replicate the effect of selinexor when used with melphalan, increasing DNA damage (γH2AX) by inhibiting DNA repair. Thus, combination therapies that include selinexor or eltanexor with melphalan may have the potential to improve treatment outcomes of multiple myeloma in melphalan-resistant and newly diagnosed patients. The combination of selinexor and melphalan is currently being investigated in the context of high-dose chemotherapy and autologous transplant (NCT02780609). SIGNIFICANCE Inhibition of exportin 1 with selinexor synergistically sensitizes human multiple myeloma to melphalan by inhibiting Fanconi anemia pathway-mediated DNA repair.Intratumoral hypoxia occurs in 90% of solid tumors and is associated with a poor prognosis for patients. Cancer cells respond to hypoxic microenvironments by activating the transcription factors, hypoxia-inducible factor 1 (HIF1) and HIF2. Here, we studied the unique gene expression patterns of 31 different breast cancer cell lines exposed to hypoxic conditions. The EGFR, a member of the ErbB (avian erythroblastosis oncogene B) family of receptors that play a role in cell proliferation, invasion, metastasis, and apoptosis, was induced in seven of the 31 breast cancer cell lines by hypoxia. A functional hypoxia response element (HRE) was identified, which is activated upon HIF1 binding to intron 18 of the EGFR gene in cell lines in which EGFR was induced by hypoxia. CpG methylation of the EGFR HRE prevented induction under hypoxic conditions. GSK’963 The HRE of EGFR was methylated in normal breast tissue and some breast cancer cell lines, and could be reversed by treatment with DNA methyltransferase inhibitors. Induction of EGFR under hypoxia led to an increase in AKT, ERK, and Rb phosphorylation as well as increased levels of cyclin D1, A, B1, and E2F, and repression of p21 in an HIF1α-dependent manner, leading to cell proliferation and migration. Also, increased EGFR expression sensitized cells to EGFR inhibitors. Collectively, our data suggest that patients with hypoxic breast tumors and hypomethylated EGFR status may benefit from EGFR inhibitors currently used in the clinic. SIGNIFICANCE Hypoxia sensitizes breast cancer cells to EGFR inhibitors in an HIF1α- and a methylation-specific manner, suggesting patients with hypoxic tumors may benefit from EGFR inhibitors already available in the clinic. GRAPHICAL ABSTRACT http//cancerres.aacrjournals.org/content/canres/80/22/4998/F1.large.jpg.In the Canakinumab Anti-inflammatory Thrombosis Outcomes Study (CANTOS), inhibition of the IL1β inflammatory pathway by canakinumab has been shown to significantly reduce lung cancer incidence and mortality. Here we performed molecular characterization of CANTOS patients who developed lung cancer during the study, including circulating tumor DNA (ctDNA) and soluble inflammatory biomarker analysis. Catalogue of Somatic Mutations in Cancer (COSMIC) database ctDNA mutations were detected in 65% (46/71) of the CANTOS patients with lung cancer, with 51% (36/71) having detectable ctDNA at the time point closest to lung cancer diagnosis and 43% (29/67) having detectable ctDNA at trial randomization. Mutations commonly found in lung cancer were observed with no evidence of enrichment in any mutation following canakinumab treatment. Median time to lung cancer diagnosis in patients with (n = 29) versus without (n = 38) detectable COSMIC ctDNA mutations at baseline was 407 days versus 837 days (P = 0.011). For serum inflammatory biomarker analysis, circulating levels of C-reactive protein (CRP), IL6, IL18, IL1 receptor antagonist, TNFα, leptin, adiponectin, fibrinogen, and plasminogen activator inhibitor-1 were determined. Patients with the highest level of baseline CRP or IL6, both downstream of IL1β signaling, trended toward a shorter time to lung cancer diagnosis. Other inflammation markers outside of the IL1β pathway at baseline did not trend with time to lung cancer diagnosis. These results provide further evidence for the importance of IL1β-mediated protumor inflammation in lung cancer and suggest canakinumab’s effect may be mediated in part by delaying disease progression of diverse molecular subtypes of lung cancer. SIGNIFICANCE These findings suggest that targeting the IL1β inflammatory pathway might be critical in reducing tumor-promoting inflammation and lung cancer incidence.Field carcinogenesis describes the prevalence of tumor-related alterations in normal appearing tissues. Here, we summarize recent efforts in profiling molecular field dynamics for resolving early events in cancer evolution. We also highlight gaps in our knowledge of the molecular and cellular heterogeneity of field carcinogenesis and propose directions to tackle these voids using single-cell-based approaches and unique tissue sampling models. By interrogating both the mutagenized epithelium and its microenvironment, we surmise that single-cell-guided studies will help chart the spatiotemporal molecular and cellular “atlas” of field carcinogenesis, will further delineate preneoplastic initiation and progression, and will help identify cancer prevention and early intervention targets.