A new tool to deliver epigenetic targeted therapeutics in Multiple Myeloma. – ETTMM (Epigenetic Targeted Treatment of

These biological questions will be investigated using:
- a unique collection of 22 exogenous IL-6 dependent myeloma cell lines. These cell lines stop cell cycling and apoptose under removal of exogenous IL-6 and are an easy model to study the function of proteins that can trigger survival, cell cycle or drug resistance. Our lab has generated one fourth of the world-available human myeloma cell lines (HMCLs) and will provide parental and drug resistant HMCLs.
- primary MMCs, which will be used with patients’ agreement as approved by our ethical Center for Biological Resources (University Hospital Montpellier). Our lab is also in charge of the Hospital laboratory performing the phenotypic and molecular diagnosis and follow-up of patients with MM. This research is approved by the Center for Biological Resources of Montpellier University Hospital (collection N° DC-2008-417).

We will test DNMT inhibitors or HDAC inhibitors alone or in association with conventional treatment of MM and correlate the drug toxicity with the “DNA methylation gene score” and “histone acetylation gene score”.

During this project, we have:
- Demonstrated that the «DNA methylation« score predicts the sensitivity of MM cell lines (n = 12) and primary cells from 14 patients to another DNMTi, 5-azacitidine (Moreaux J et al. British journal of Haematology, 2014).
- Demonstrated that the «histone acetylation« score, built using trichostatin A, predicts also the sensitivity of MM cells to 3 other HDACi: panobinostat, vorinostat and valproic acid (Moreaux J et al. British journal of cancer. 2013).
- Among the genes whose expression is inhibited by DNMTi and associated with a poor prognosis in MM patients, we have identified RECQ1. RECQ1 is a RECQ helicase family member. We confirmed the expression of RECQ1 in a large panel of MM cell lines and in primary cells of patients. We have demonstrated that RECQ1 depletion in MM cells inhibits cell growth, induces apoptosis and spotaneous 53BP1 foci formation indicating the presence of DNA double strand breaks. We have demonstrated that RECQ1 depletion significantly sensitizes MM cells to melphalan suggesting that combination of DNMTi to target RECQ1 expression with melphalan could have a therapeutic interest in patients with MM.
- Recent data have shown the therapeutic potential of the HDACi + DNMTi combination in several cancers and in MM. Using the same methodology, we have created a gene-based score to predict the sensitivity of MM cells to HDACi (TSA or Vorinostat) + DNMTi (Decitabine or 5-azacitidine) combination. This work was patented in 2014: Method for Predicting DNMTi / HDACi combination treatment response in Multiple Myeloma. Moreaux J, Klein B. EP14305404, 2014.

There are about 25000 newly-diagnosed patients per year in the EU, and the costs of myeloma treatments are among the highest of cancer treatment costs. The cost of the novel drugs used in this disease is 70 K€/year/patient, for about 150,000 treated patients in the EU. This work could deliver new tools to progress in the treatment of MM patients and maximize the benefit/cost ratio. This project will also lead to progress in the understanding of the epigenetic landscape in MM.

Patents:
1. Method for predicting multiple myeloma treatment response. WO11298.
2. Method for predicting HDACi treatment response in Multiple Myeloma. WO11098.
3. Method for predicting DNMTi/HDACi combination treatment response in Multiple Myeloma. EP14305404.

Scientific production:
1. Moreaux J, Reme T, Leonard W, Veyrune JL, Requirand G, Goldschmidt H, Hose D, Klein B. Gene expression based prediction of myeloma cell sensitivity to histone deacetylase inhibitors. British Journal of Cancer. 2013 Aug 6;109(3):676-85.
2. Moreaux J, Bruyer A, Veyrune JL, Goldschmidt H, Hose D, Klein B. DNA methylation score is predictive of myeloma cell sensitivity to 5-azacitidine. Br J Haematol. 2014 Feb;164(4):613-6

Multiple Myeloma (MM) is a still lethal disease in 2012 characterized by the accumulation in the bone marrow of a clone of malignant plasma cells (MMC for multiple myeloma cells). High dose chemotherapy (HDC) and hematopoietic stem cell (HSC) transplantation, in association with novel drugs as proteasome inhibitor (Bortezomib) or immunomodulatory agents (Lenalidomide and Thalidomide) have allowed survival improvement.
Genomic instability is a characteristic feature of myeloma cells. Although there has been substantial work performed on the genetics of myeloma, little is known about the epigenetic changes leading to disease progression. Recent studies have shown that epigenetic modifications such as DNA methylation play a role by silencing various cancer-related genes in MM. DNA methyltransferase (DNMT) inhibitors or histone deacetylase (HDAC) inhibitors are now being used in the treatment of some hematologic malignancies, including MM.
Here, we describe the results of a microarray-based genome-wide screen for genes responding to DNMT inhibition and HDAC inhibition in MM cell lines. Based on the results of our microarray assay, we built new “DNA methylation gene score” and “histone acetylation gene score” that make it possible identification of myeloma patients that will be sensitive to DNMT inhibitors or HDAC inhibitors. In our project, we plan to realize the proof of concept on our large panel of myeloma cell lines and primary myeloma cells. We will test DNMT inhibitors or HDAC inhibitors alone or in association with conventional treatment of MM and correlate the drug toxicity with the “DNA methylation gene score” and “histone acetylation gene score”. There are 2000 newly-diagnosed patients with MM in France, about 20000 in EU, and the costs of myeloma treatments are among the highest of cancer treatment costs. This work could deliver new tools to progress in the treatment of MM patients and maximize the benefit/cost ratio.