Haug, Jessica

Abstract Detection of specific chromosomal abnormalities by FISH and metaphase cytogenetics allows risk stratification in multiple myeloma; however, gene expression profiling (GEP) based signatures may enable more specific risk categorization. We examined the utility of 2 GEP-based risk stratification systems among patients undergoing initial therapy with lenalidomide in the context of a phase 3 trial. Among 45 patients studied at baseline, 7 (16%) and 10 (22%), respectively, were high-risk using the GEP70 and GEP15 signatures. The median overall survival for the GEP70 high-risk group was 19 months versus not reached for the rest (hazard ratio = 14.1). Although the medians were not reached, the GEP15 also predicted a poor outcome among the high-risk patients. The C-statistic for the GEP70, GEP15, and FISH based risk stratification systems was 0.74, 0.7, and 0.7, respectively. Here we demonstrate the prognostic value for GEP risk stratification in a group of patients primarily treated with novel agents. This trial was registered at www.clinicaltrials.gov as #NCT00098475.

Abstract Background: Cytokine stimulated signaling pathways contribute to multiple myeloma (MM) disease progression and in acquired resistance to current treatment options making MM an incurable malignancy. The PI3K/Akt/mTOR pathway is up-regulated in MM and appears to be critical for cell proliferation and blocking this pathway might have profound impact on disease progression. In addition, this pathway also has been found to cross talk with other signal transduction pathways preventing drug-induced apoptosis. Methods: MK2206 was obtained from Merck Inc. MTT assay was performed to study drug induced cytotoxicity and thymidine uptake was used as a measure to study differences in proliferation. Flow cytometry using Annexin V-FITC and propidium iodide (PI) was used to measure drug induced apoptosis in cell lines and patient cells. In addition, apo-2.7 was also used to measure apoptosis in patient cells. Results: MK2206 treatment led to dose and time dependent decrease in cell viability as observed by MTT assay with an IC50 range of 1-5µM on most MM cell lines tested. Most of the cytotoxicity was observed by 48hours with minimal increase in cytotoxicity beyond that point. The drug was able to induce cytotoxicity in myeloma cell lines when cells were cultured with IGF, IL6, or VEGF with minimal increase in IC50 values. MK2206 also inhibited MM cell proliferation as observed by reduced thymidine uptake. This reduction in proliferation was also observed when MM cells were co-cultured with bone marrow stromal cells. When myeloma cell lines were treated with the drug for various time points, percentage of apoptotic cells increased with time of incubation with the drug as observed by flow cytometry and annexin V-FITC/PI staining. There was also a time dependent increase in caspase cleavage observed indicating that MK2206 might elicit its functions by inducing caspase dependent pathways. Further studies are being carried out to understand the importance of caspase dependent pathways for the success of anti-MM effects of MK2206. Also, MK2206 was able to induce apoptosis in patient derived primary cells, though with varying degrees of response observed between patients. Examining signaling pathways by immunoblotting demonstrated clear down regulation of pAkt and Bcl-xl levels post treatment with the drug with minimal decrease in proteins associated with other signaling pathways, like pSTAT3 and pERK. Conclusions: Taken together, our studies demonstrate significant anti-MM activity of MK2206 in-vitro. We are currently testing MK2206 in combination with known inhibitors of the other important signaling pathways implicated in MM disease biology as well as in-vivo experiments in mouse models. Performing these experiments will further validate the efficacy of MK2206 as an anti-MM agent and form the basis for it to be taken up for clinical evaluation either as a single agent or in combination with other agent(s). Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1796.

AbstractWe compared the angiogenic potential of bone marrow plasma and the expression of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and their receptors on plasma cells from patients with monoclonal gammopathy of undetermined significance (MGUS), smoldering multiple myeloma (SMM), and newly diagnosed multiple myeloma (NMM). Cytokine and cytokine-receptor expression was studied by bone marrow immunohistochemistry, quantitative reverse transcription-polymerase chain reaction (RT-PCR) on sorted plasma cells, and quantitative Western blot analysis. Bone marrow angiogenic potential was studied using a human in vitro angiogenesis assay. The expression levels of VEGF, bFGF, and their receptors were similar among MGUS, SMM, and NMM. Sixty-one percent of NMM samples stimulated angiogenesis in the in vitro angiogenesis assay compared with SMM (0%) and MGUS (7%) (P < .001). Importantly, 63% of MGUS samples inhibited angiogenesis compared with SMM (43%) and NMM (4%) (P < .001). The inhibitory activity was heat stable, not overcome by the addition of VEGF, and corresponded to a molecular weight below 10 kd by size-exclusion chromatography. Our results suggest that increasing angiogenesis from MGUS to NMM is, at least in part, explained by increasing tumor burden rather than increased expression of VEGF/bFGF by individual plasma cells. The active inhibition of angiogenesis in MGUS is lost with progression, and the angiogenic switch from MGUS to NMM may involve a loss of inhibitory activity. (Blood. 2004; 104:1159-1165)