Mechanism underpinning synergy with combined treatment of MTI-101 and Dexamethasone in Multiple Myeloma

ABSTRACT Multiple myeloma (MM) is the second most common hematopoietic cancer and while survival rates have slowly increase in the last 10 years, the five-year survival is just over 50%. The high number of patients that become refractory to current therapies is the core reason for the low long-term survival. Therefore, there is a crucial need to develop unique drugs that are active in refractory and resistant patients. Modulation Therapeutics is developing a first in class peptide, MTI-101, that stimulates a CD44/ITGA4 complex resulting in an increase of intracellular Ca2+ levels inducing necrosis. The company has acquired patents for the parent molecule, MTI-101, and derivative (MTI-102) covering the intellectual property for both composition of matter and use in cancer. Non-GLP and GLP toxicity testing are slated to be done soon in preparation for the submission of an IND package to the FDA. Thus, Modulation Therapeutics provides the ideal environment to receive the training required to obtain the next level position in drug development in any pharmaceutical company. Women are greatly under-represented in upper administrative positions in part due to the lack to training needed to progress from the entry-level research workforce. One goal of this proposal is to provide the research and entrepreneurial skills underpinning the transition to administrative positions such as director of drug development. To receive that training, the female senior scientist at Modulation Therapeutics will be involved in all stages of developing, assembling, and submitting the IND package to the FDA. In addition, the leadership training will include the development and role as project leader of a parallel research project proposed in this revision. The research project will investigate the synergistic interaction of the lead compound for Modulation Therapeutics, MTI-101 and dexamethasone (Dex), a common drug administered in combination regimen for treatment of MM. Both MTI- 101 and Dex modulate calcium flux in cells and combination therapy with Dex and MTI-101 would likely increase MTI-101 Ca2+ induced programmed necrosis. We found that combination treatment of MTI-101/Dex increased cell death and resulted in greatest synergistic activity in MM cell lines pretreatment with Dex (24 h) followed by an additional Dex/MTI-101 treatment (16 h). Based on these results, we hypothesize that dexamethasone is modulating the expression of proteins involved in store-operated channels to potentiate MTI-101 mediated by Ca2+ induced necrosis. Live-cell imaging of Ca2+ flux and cell death using Dex-treated MM cells exposed to an MTI-101/Dex combination treatment provide insight into the mechanism of the observed synergy. Furthermore, in vitro analysis of Dex mediated of expression of proteins involved in calcium flux by qRT-PCR, Western Blot, and RNA seq will further elucidate the mechanism of action facilitating the cell death observed with MTI-101/ Dex combination therapy. MTI-101/ Dex combination treatment versus single agents using a MM mouse model will confirm in vitro results translate to a more complex system. As MTI-101 moves forward in drug development the understanding of MTI-101 efficacy in the context of standard of care MM agents is crucial.PROJECT NARRATIVE Multiple Myeloma is currently a disease that initially response to treatment but is not cured with available drugs. Unfortunately as the disease progresses resistance to therapy emerges and thus clinical data continues to support the need to develop novel strategies for the treatment of MM such as MTI-101 that targets a unique cell death pathway to improve patient outcomes.