Mengxiong Wang

All Publications

• A Balancing Act: p53 Activity from Tumor Suppression to Pathology and Therapeutic Implications. Annual review of pathology Wang, M., Attardi, L. D. 2021

  Abstract

  TP53, encoding the p53 transcription factor, is the most frequently mutated tumor suppressor gene across all human cancer types. While p53 has long been appreciated to induce antiproliferative cell cycle arrest, apoptosis, and senescence programs in response to diverse stress signals, various studies in recent years have revealed additional important functions for p53 that likely also contribute to tumor suppression, including roles in regulating tumor metabolism, ferroptosis, signaling in the tumor microenvironment, and stem cell self-renewal/differentiation. Not only does p53 loss or mutation cause cancer, but hyperactive p53 also drives various pathologies, including developmental phenotypes, premature aging, neurodegeneration, and side effects of cancer therapies. These findings underscore the importance of balanced p53 activity and influence our thinking of how to best develop cancer therapies based on modulating the p53 pathway. Expected final online publication date for the Annual Review of Pathology: Mechanisms of Disease, Volume 17 is January 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

  View details for DOI 10.1146/annurev-pathol-042320-025840

  View details for PubMedID 34699262

• Zmat3 Is a Key Splicing Regulator in the p53 Tumor Suppression Program. Molecular cell Bieging-Rolett, K. T., Kaiser, A. M., Morgens, D. W., Boutelle, A. M., Seoane, J. A., Van Nostrand, E. L., Zhu, C., Houlihan, S. L., Mello, S. S., Yee, B. A., McClendon, J., Pierce, S. E., Winters, I. P., Wang, M., Connolly, A. J., Lowe, S. W., Curtis, C., Yeo, G. W., Winslow, M. M., Bassik, M. C., Attardi, L. D. 2020; 80 (3): 452

  Abstract

  Although TP53 is the most commonly mutated gene in human cancers, the p53-dependent transcriptional programs mediating tumor suppression remain incompletely understood. Here, to uncover critical components downstream of p53 in tumor suppression, we perform unbiased RNAi and CRISPR-Cas9-based genetic screens invivo. These screens converge upon the p53-inducible gene Zmat3, encoding an RNA-binding protein, and we demonstrate that ZMAT3 is an important tumor suppressor downstream of p53 in mouse KrasG12D-driven lung and liver cancers and human carcinomas. Integrative analysis of the ZMAT3 RNA-binding landscape and transcriptomic profiling reveals that ZMAT3 directly modulates exon inclusion in transcripts encoding proteins of diverse functions, including the p53 inhibitors MDM4 and MDM2, splicing regulators, and components of varied cellular processes. Interestingly, these exons are enriched in NMD signals, and, accordingly, ZMAT3 broadly affects target transcript stability. Collectively, these studies reveal ZMAT3 as a novel RNA-splicing and homeostasis regulator and a key component of p53-mediated tumor suppression.

  View details for DOI 10.1016/j.molcel.2020.10.022

  View details for PubMedID 33157015

• A novel proteotoxic combination therapy for EGFR+ and HER2+cancers ONCOGENE Wang, M., Ferreira, R. B., Law, M. E., Davis, B. J., Yaaghubi, E., Ghilardi, A. F., Sharma, A., Avery, B. A., Rodriguez, E., Chiang, C., Narayan, S., Heldermon, C. D., Castellano, R. K., Law, B. K. 2019; 38 (22): 4264–82

  Abstract

  While HER2 and EGFR are overexpressed in breast cancers and multiple other types of tumors, the use of EGFR and/or HER2 inhibitors have failed to cure many cancer patients, largely because cancers acquire resistance to HER2/EGFR-specific drugs. Cancers that overexpress the HER-family proteins EGFR, HER2, and HER3 are uniquely sensitive to agents that disrupt HER2 and EGFR protein folding. We previously showed that disruption of disulfide bond formation by Disulfide Disrupting Agents (DDAs) kills HER2/EGFR overexpressing cells through multiple mechanisms. Herein, we show that interference with proline isomerization in HER2/EGFR overexpressing cells also induces cancer cell death. The peptidyl-prolyl isomerase inhibitor Cyclosporine A (CsA) selectively kills EGFR+ or HER2+ breast cancer cells in vitro by activating caspase-dependent apoptotic pathways. Further, CsA synergizes with the DDA tcyDTDO to kill HER2/EGFR overexpressing cells in vitro and the two agents cooperate to kill HER2+ tumors in vivo. There is a critical need for novel strategies to target HER2+ and EGFR+ cancers that are resistant to currently available mechanism-based agents. Drugs that target HER2/EGFR protein folding, including DDAs and CsA, have the potential to kill cancers that overexpress EGFR or HER2 through the induction of proteostatic synthetic lethality.

  View details for DOI 10.1038/s41388-019-0717-6

  View details for Web of Science ID 000469339100005

  View details for PubMedID 30718919

• The unfolded protein response as a target for anticancer therapeutics CRITICAL REVIEWS IN ONCOLOGY HEMATOLOGY Wang, M., Law, M. E., Castellano, R. K., Law, B. K. 2018; 127: 66–79

  Abstract

  The endoplasmic reticulum (ER) is an essential organelle in eukaryotic cells, responsible for protein synthesis, folding, sorting, and transportation. ER stress is initiated when the unfolded or misfolded protein load exceeds the capacity of the ER to properly fold protein. Tumor microenvironmental conditions, such as nutrient deprivation, hypoxia, and oxidative stress perturb protein folding and trigger chronic ER stress. Cancer cells can tolerate mild ER stress, however, persistent and severe ER stress kills cancer cells by inducing their autophagy, apoptosis, necroptosis, or immunogenic cell death. Based on this rationale, many drugs have been developed for triggering irremediable ER stress in cancer cells by targeting various processes in the secretory pathway. This review discusses the mechanisms of protein targeting to the ER, the key signaling cassettes that are involved in the ER stress response, and their correlation with cancer formation and progression. Importantly, this review discusses current experimental and FDA approved anti-cancer drugs that induce ER stress, and emerging targets within the secretory pathway for the development of new anticancer drugs.

  View details for DOI 10.1016/j.critrevonc.2018.05.003

  View details for Web of Science ID 000437044500008

  View details for PubMedID 29891114

• Disulfide bond disrupting agents activate the unfolded protein response in EGFR- and HER2-positive breast tumor cells ONCOTARGET Ferreira, R. B., Wang, M., Law, M. E., Davis, B. J., Bartley, A. N., Higgins, P. J., Kilberg, M. S., Santostefano, K. E., Terada, N., Heldermon, C. D., Castellano, R. K., Law, B. K. 2017; 8 (17): 28971–89

  Abstract

  Many breast cancer deaths result from tumors acquiring resistance to available therapies. Thus, new therapeutic agents are needed for targeting drug-resistant breast cancers. Drug-refractory breast cancers include HER2+ tumors that have acquired resistance to HER2-targeted antibodies and kinase inhibitors, and "Triple-Negative" Breast Cancers (TNBCs) that lack the therapeutic targets Estrogen Receptor, Progesterone Receptor, and HER2. A significant fraction of TNBCs overexpress the HER2 family member Epidermal Growth Factor Receptor (EGFR). Thus agents that selectively kill EGFR+ and HER2+ tumors would provide new options for breast cancer therapy. We previously identified a class of compounds we termed Disulfide bond Disrupting Agents (DDAs) that selectively kill EGFR+ and HER2+ breast cancer cells in vitro and blocked the growth of HER2+ breast tumors in an animal model. DDA-dependent cytotoxicity was found to correlate with downregulation of HER1-3 and Akt dephosphorylation. Here we demonstrate that DDAs activate the Unfolded Protein Response (UPR) and that this plays a role in their ability to kill EGFR+ and HER2+ cancer cells. The use of breast cancer cell lines ectopically expressing EGFR or HER2 and pharmacological probes of UPR revealed all three DDA responses: HER1-3 downregulation, Akt dephosphorylation, and UPR activation, contribute to DDA-mediated cytotoxicity. Significantly, EGFR overexpression potentiates each of these responses. Combination studies with DDAs suggest that they may be complementary with EGFR/HER2-specific receptor tyrosine kinase inhibitors and mTORC1 inhibitors to overcome drug resistance.

  View details for DOI 10.18632/oncotarget.15952

  View details for Web of Science ID 000400050000113

  View details for PubMedID 28423644

  View details for PubMedCentralID PMC5438706