Dual Targeting of the PDZ1 and PDZ2 Domains of MDA-9/Syntenin Inhibits Melanoma Metastasis.

Drs. Paul B Fisher and Swadesh K. Das’ research teams engineered a new small molecule inhibitor, IVMT-Rx-3, which is a unique MDA-9/Syntenin antagonist that simultaneously binds and blocks activity of both PDZ domains and effectively inhibits melanoma metastasis. Additionally, this molecule can be used in combination with conventional immunotherapeutic agents to enhance efficacy against metastatic melanoma. Importantly, these strategies could be extended to target a wide range of additional human cancers characterized by overexpression of MDA-9/Syntenin.

This research has been featured on the cover page of the Molecular Cancer Therapeutics (MCT) journal and highlighted in MCT as a First Disclosure of a new therapeutic molecule.

Genome-wide gene expression analysis and animal modeling indicate that melanoma differentiation associated gene-9 (mda-9, Syntenin, Syndecan binding protein, referred to as MDA-9/Syntenin) positively regulates melanoma metastasis. The MDA-9/Syntenin protein contains two tandem PDZ domains serving as a nexus for interactions with multiple proteins that initiate transcription of metastasis-associated genes. Although targeting either PDZ domain abrogates signaling and pro-metastatic phenotypes, the integrity of both domains is critical for full biological function. Fragment-based drug discovery and NMR identified PDZ1i, an inhibitor of the PDZ1 domain that effectively blocks cancer invasion in vitro and in vivo in multiple experimental animal models. To maximize disruption of MDA-9/Syntenin signaling, an inhibitor has now been developed that simultaneously binds and blocks activity of both PDZ domains. PDZ1i was joined to the second PDZ binding peptide (TNYYFV) with a PEG linker, resulting in PDZ1i/2i (IVMT-Rx-3) that engages both PDZ domains of MDA-9/Syntenin. IVMT-Rx-3 blocks MDA-9/Syntenin interaction with Src, reduces NF-κB activation, and inhibits MMP-2/MMP-9 expression, culminating in repression of melanoma metastasis. The in vivo antimetastatic properties of IVMT-Rx-3 are enhanced when combined with an immune-checkpoint inhibitor. Collectively, the results support the feasibility of engineering MDA-9 dual-PDZ inhibitors with enhanced antimetastatic activities and applications of IVMT-Rx-3 for developing novel therapeutic strategies effectively targeting melanoma and in principle, a broad spectrum of human cancers that also overexpress MDA-9/Syntenin.

Figure legend: Proposed mechanism of action of the MDA-9/Syntenin-1/SDCBP pharmacological inhibitor IVMT-Rx-3. Through the disruption of the interactions between MDA-9/Syntenin and cSrc, IVMT-Rx-3 deactivates NF-kB suppressing invasion and angiogenesis associated genes and blocking tumor cell migration. Additionally, IVMT-Rx-3 inhibits the expression of NF-kB dependent inflammatory cytokine expression, boosting anti-tumor immunity and blocking the proliferation of melanoma cells in the metastatic niche.

Publications:

Pradhan AK, Modi J, Maji S, Kumar A, Bhoopathi P, Mannangatti P, Guo C, Afosah DK, Mochel MC, Mukhopadhyay ND, Kirkwood JM, Wang XY, Desai UR, Sarkar D, Emdad L, Das SK, Fisher PB. Dual Targeting of the PDZ1 and PDZ2 Domains of MDA-9/Syntenin Inhibits Melanoma Metastasis. Mol Cancer Ther. 2023 Oct 2;22(10):1115-1127. DOI: 10.1158/1535-7163.MCT-22-0653

About the Investigators: Paul B. Fisher, MPh, PhD, FNAI, is Professor of the VCU Department of Human and Molecular Genetics (HMG), Director of the VCU Institute of Molecular Medicine (VIMM) and holds the Thelma Newmeyer Corman Chair in Cancer Research in the VCU Massey Comprehensive Cancer Center (MCCC), Virginia Commonwealth University (VCU), School of Medicine (SOM), Richmond, VA. Anjan K Pradhan, PhD, the lead author of this research study is an instructor in HMG. Jinkal Modi is a PhD student in HMG. Santanu Maji, PhD and Amit Kumar, PhD are Postdoctoral research scientists in HMG. Praveen Bhoopathi, PhD is an instructor in HMG. Padmanabhan Mannangatti, PhD is a senior technician and laboratory manager in the Fisher laboratory. Xiang-Yang Wang, PhD, is Harry and Judy Wason Distinguished Professor in HMG; Associate Scientific Director of Immunology in the VIMM; and co-leader of Developmental Therapeutics Program, MCCC, VCU SOM, Richmond, VA. Chunqing Guo, PhD, former Assistant Professor in HMG. Daniel K. Afosah, PhD, is in the department of Medicinal Chemistry, School of Pharmacy, VCU. Umesh R. Desai, PhD, Professor and Chairman, Department of Medicinal Chemistry, VCU. Mark C. Mochel, MD, Associate Professor of Pathology and Dermatology; Director of Dermatopathology, VCU SOM. Nitai D. Mukhopadhyay, PhD, Associate Professor, Department of Biostatistics, VCU. John M. Kirkwood, MD, Distinguished Service Professor of Medicine, Dermatology & Translational Science Co-Leader, Melanoma and Skin Cancer Program, University of Pittsburgh Medical Center. Devanand Sarkar, MBBS, PhD, is a Professor in HMG, VCU SOM, as well as the Harrison Foundation Distinguished Professor in Cancer Research. He is Associate Director for Training and Education of the MCCC, and Associate Scientific Director, Cancer Therapeutics, VIMM. Luni Emdad, MBBS, PhD is Associate Professor in HMG and a Member of the VIMM. Swadesh K. Das, PhD, is Associate Professor in HMG and Member of the VIMM and co-corresponding author of this study.

This study was supported in part by NIH/NCI Grants R01 CA244993 (to D. Sakar and P.B. Fisher) and CA099326 and CA229812 (to X.-Y. Wang); NCI Cancer Center Support Grant to the Virginia Commonwealth University (VCU) Massey Comprehensive Cancer Center (MCC) P30 CA016059 (to Robert Winn); the National Foundation for Cancer Research (P.B. Fisher); and a Sponsored Research Agreement between VCU and InVaMet Therapeutics (to S.K. Das). P.B. Fisher holds the Thelma Newmeyer Corman Chair in Cancer Research at the MCCC. D. Sarkar is the Harrison Foundation Distinguish Professor in Cancer Research at the MCC. X.-Y. Wang holds the Harry and Judy Wason Chair in Cancer Research at the MCC. This research was also facilitated by the VCU MCC Flow Cytometry Shared Resource and Cancer Mouse Models Core Laboratory, supported, in part, with funding from NIH/NCI Cancer Center Support Grant P30 CA016059. This study was supported in part by Commonwealth Health Research Board (236-04-20; P.B. Fisher).