Cyproheptadine displays preclinical activity in myeloma and leukemia

Abstract

Introduction D-type cyclins are critical regulators of the cell cycle that act in a complex with cyclin-dependent kinases (CDKs) to promote the phosphorylation of Rb and initiate cellular transition from G 1 to S phase. 1 Overexpression of D-cyclins occurs in many tumors and leads to increased cell proliferation 2-4 and chemoresistance. 5 In contrast, reducing D-cyclins directly or indirectly can decrease cellular proliferation and induce apoptosis. [6][7][8] Aberrant expression of one or more D-cyclins is virtually universal in multiple myeloma (MM), with 54% of myeloma tumors overexpressing cyclin D1, 48% overexpressing cyclin D2, 3% overexpressing cyclin D3, and 8% overexpressing both cyclin D1 and D2. 9 The overexpression of D-cyclins contributes to the pathogenesis and chemoresistance of this disease. 3,4,9 The t(11;14) involving cyclin D1 is found in 15% to 20% of myeloma patients and is associated with improved survival. 10 However, levels of cyclin D1 protein often do not correlate as well with prognosis. 11 In contrast, patients with myeloma and increased cyclin D2 expression, especially in cooperation with the presence of other oncogenes, such as c-Maf, MafB, and FGFR3/MMSET, have an inferior event-free survival. 12 Likewise, D-cyclins are increased in a subset of patients with acute myeloid leukemia and are associated with poor outcome. 13 To better understand the regulation of D-cyclins and the effects of targeting their expression in myeloma and leukemia cells, we conducted a chemical screen for inhibitors of the human cyclin D2 promoter using NIH3T3 cells engineered to overexpress the cyclin D2 promoter driving firefly luciferase. From this screen, we identified glucocorticoids and demonstrated that these drugs inhibit cyclin D2 transactivation by increasing the proteasomal degradation of c-maf via increased ubiquitin expression. 14 Here we identify that cyproheptadine inhibits the transactivation of cyclin D2 through mechanisms independent of c-maf. Cyproheptadine is a known inhibitor of the H1 histamine and 5-HT serotonin receptors. Previously, cyproheptadine has been evaluated in patients for the treatment of migraines, 15 anorexia, 16 and atopic dermatitis. 17 In clinical trials, the drug was well tolerated without hematologic toxicity. The ability of cyproheptadine to inhibit D-cyclin expression has not been reported previously. In this report, we evaluated the effects of cyproheptadine on myeloma and leukemia cell lines as well as primary patient samples. Cyproheptadine decreased D-cyclin levels and induced cell death in myeloma and leukemia cell lines and patient samples preferentially over normal hematopoietic cells. Finally, cyproheptadine demonstrated activity in mouse models of leukemia and myeloma. Thus, cyproheptadine represents a lead for a novel therapeutic agent for the treatment of malignancy. Methods Chemicals and reagentsCyproheptadine hydrochloride, amitriptyline, loratadine, thymidine, histamine, serotonin, and propidium iodine (PI) were purchased from SigmaAldrich (St Louis, M...

The Antiparasitic Clioquinol Induces Apoptosis in Leukemia and Myeloma Cells by Inhibiting Histone Deacetylase Activity

“…The cells were then treated with DNase-free RNase (Invitrogen) before staining with 50 g/ml of propidium iodide. The detailed procedure and cell cycle analysis was performed as reported previously (25).…”

A small-molecule inhibitor of D-cyclin transactivation displays preclinical efficacy in myeloma and leukemia via phosphoinositide 3-kinase pathway

“…37 Consistent with these effects, increased activation of the PI3K pathway is prognostically important in patients with myeloma and leukemias. 14,38 For example, increased levels of phospho-AKT (Ser473) are associated with worse overall survival and worse response to reinduction chemotherapy in patients with acute myeloid leukemia. 39 AKT phosphorylation is critical for S14161-induced blood cancer cell apoptosis, because U266 lacking a phosphorylated AKT is resistant to S14161-induced cell death.…”

“…12,13 The appetite-stimulant cyproheptadine decreases D-cyclin expression and induces cell death in myeloma cells through a mechanism distinct from the drug's known activity as an H1 histamine and serotonin receptor antagonist. 14 Finally, the natural product kinetin riboside inhibits transactivation of cyclins D1 and D2 by upregulating the expression of the transcription repressor isoforms of the cyclic adenosine monophosphate-responsive element modulator (CREM). 15 Some of these compounds, such as dexamethasone, are clinically used for myeloma treatment or are being tested in a clinical setting for refractory leukemia treatment.…”

Development and validation of LC–MS/MS method for the determination of cyproheptadine in several pharmaceutical syrup formulations

“…Investigations with animals suggested that CP has obvious therapeutic effects on traumatic brain oedema [5], can protect spinal cord ischemic injury [6], increase cerebral blood flow causing cerebral vasodilation [7], and can induce anti-shock effects [8]. More recently, CP was identified as the lead novel therapeutic agent for the treatment of cancer, as an inhibitor of d-cyclin expression, leading to induced cell death and delayed tumour growth in mouse models [9].…”