51
|
Hua AB, Justiniano R, Perer J, Park SL, Li H, Cabello CM, Wondrak GT. Repurposing the Electron Transfer Reactant Phenazine Methosulfate (PMS) for the Apoptotic Elimination of Malignant Melanoma Cells through Induction of Lethal Oxidative and Mitochondriotoxic Stress. Cancers (Basel) 2019; 11:cancers11050590. [PMID: 31035569 PMCID: PMC6562717 DOI: 10.3390/cancers11050590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 04/24/2019] [Accepted: 04/25/2019] [Indexed: 12/21/2022] Open
Abstract
Redox-directed pharmacophores have shown potential for the apoptotic elimination of cancer cells through chemotherapeutic induction of oxidative stress. Phenazine methosulfate (PMS), a N-alkylphenazinium cation-based redox cycler, is used widely as an electron transfer reactant coupling NAD(P)H generation to the reduction of tetrazolium salts in biochemical cell viability assays. Here, we have explored feasibility of repurposing the redox cycler PMS as a superoxide generating chemotherapeutic for the pro-oxidant induction of cancer cell apoptosis. In a panel of malignant human melanoma cells (A375, G361, LOX), low micromolar concentrations of PMS (1-10 μM, 24 h) displayed pronounced apoptogenicity as detected by annexin V-ITC/propidium iodide flow cytometry, and PMS-induced cell death was suppressed by antioxidant (NAC) or pan-caspase inhibitor (zVAD-fmk) cotreatment. Gene expression array analysis in A375 melanoma cells (PMS, 10 µM; 6 h) revealed transcriptional upregulation of heat shock (HSPA6, HSPA1A), oxidative (HMOX1) and genotoxic (EGR1, GADD45A) stress responses, confirmed by immunoblot detection demonstrating upregulation of redox regulators (NRF2, HO-1, HSP70) and modulation of pro- (BAX, PUMA) and anti-apoptotic factors (Bcl-2, Mcl-1). PMS-induced oxidative stress and glutathione depletion preceded induction of apoptotic cell death. Furthermore, the mitochondrial origin of PMS-induced superoxide production was substantiated by MitoSOX-Red live cell fluorescence imaging, and PMS-induced mitochondriotoxicity (as evidenced by diminished transmembrane potential and oxygen consumption rate) was observable at early time points. After demonstrating NADPH-driven (SOD-suppressible) superoxide radical anion generation by PMS employing a chemical NBT reduction assay, PMS-induction of oxidative genotoxic stress was substantiated by quantitative Comet analysis that confirmed the introduction of formamido-pyrimidine DNA glycosylase (Fpg)-sensitive oxidative DNA lesions in A375 melanoma cells. Taken together, these data suggest feasibility of repurposing the biochemical reactant PMS as an experimental pro-oxidant targeting mitochondrial integrity and redox homeostasis for the apoptotic elimination of malignant melanoma cells.
Collapse
Affiliation(s)
- Anh B Hua
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Rebecca Justiniano
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Jessica Perer
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Sophia L Park
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Hui Li
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Christopher M Cabello
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| | - Georg T Wondrak
- Department of Pharmacology and Toxicology, College of Pharmacy & Arizona Cancer Center, University of Arizona, Tucson, AZ 85724, USA.
| |
Collapse
|
52
|
Turdo A, Veschi V, Gaggianesi M, Chinnici A, Bianca P, Todaro M, Stassi G. Meeting the Challenge of Targeting Cancer Stem Cells. Front Cell Dev Biol 2019; 7:16. [PMID: 30834247 PMCID: PMC6387961 DOI: 10.3389/fcell.2019.00016] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/01/2019] [Indexed: 12/18/2022] Open
Abstract
Notwithstanding cancer patients benefit from a plethora of therapeutic alternatives, drug resistance remains a critical hurdle. Indeed, the high mortality rate is associated with metastatic disease, which is mostly incurable due to the refractoriness of metastatic cells to current treatments. Increasing data demonstrate that tumors contain a small subpopulation of cancer stem cells (CSCs) able to establish primary tumor and metastasis. CSCs are endowed with multiple treatment resistance capabilities comprising a highly efficient DNA damage repair machinery, the activation of survival pathways, enhanced cellular plasticity, immune evasion and the adaptation to a hostile microenvironment. Due to the presence of distinct cell populations within a tumor, cancer research has to face the major challenge of targeting the intra-tumoral as well as inter-tumoral heterogeneity. Thus, targeting molecular drivers operating in CSCs, in combination with standard treatments, may improve cancer patients’ outcomes, yielding long-lasting responses. Here, we report a comprehensive overview on the most significant therapeutic advances that have changed the known paradigms of cancer treatment with a particular emphasis on newly developed compounds that selectively affect the CSC population. Specifically, we are focusing on innovative therapeutic approaches including differentiation therapy, anti-angiogenic compounds, immunotherapy and inhibition of epigenetic enzymes and microenvironmental cues.
Collapse
Affiliation(s)
- Alice Turdo
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Veronica Veschi
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Miriam Gaggianesi
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Aurora Chinnici
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Paola Bianca
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| | - Matilde Todaro
- Department of PROMISE, University of Palermo, Palermo, Italy
| | - Giorgio Stassi
- Department of Surgical, Oncological and Stomatological Sciences, University of Palermo, Palermo, Italy
| |
Collapse
|
53
|
Sridharan S, Howard CM, Tilley AMC, Subramaniyan B, Tiwari AK, Ruch RJ, Raman D. Novel and Alternative Targets Against Breast Cancer Stemness to Combat Chemoresistance. Front Oncol 2019. [PMID: 31681564 DOI: 10.3389/fonc.2019.01003.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023] Open
Abstract
Breast cancer stem cells (BCSCs) play a vital role in tumor progression and metastasis. They are heterogeneous and inherently radio- and chemoresistant. They have the ability to self-renew and differentiate into non-BCSCs. These determinants of BCSCs including the plasticity between the mesenchymal and epithelial phenotypes often leads to minimal residual disease (MRD), tumor relapse, and therapy failure. By studying the resistance mechanisms in BCSCs, a combinatorial therapy can be formulated to co-target BCSCs and bulk tumor cells. This review addresses breast cancer stemness and molecular underpinnings of how the cancer stemness can lead to pharmacological resistance. This might occur through rewiring of signaling pathways and modulated expression of various targets that support survival and self-renewal, clonogenicity, and multi-lineage differentiation into heterogeneous bulk tumor cells following chemotherapy. We explore emerging novel and alternative molecular targets against BC stemness and chemoresistance involving survival, drug efflux, metabolism, proliferation, cell migration, invasion, and metastasis. Strategic targeting of such vulnerabilities in BCSCs may overcome the chemoresistance and increase the longevity of the metastatic breast cancer patients.
Collapse
Affiliation(s)
- Sangita Sridharan
- Department of Cancer Biology, University of Toledo, Toledo, OH, United States
| | - Cory M Howard
- Department of Cancer Biology, University of Toledo, Toledo, OH, United States
| | - Augustus M C Tilley
- Department of Cancer Biology, University of Toledo, Toledo, OH, United States
| | | | - Amit K Tiwari
- Department of Pharmacology and Experimental Therapeutics, University of Toledo, Toledo, OH, United States
| | - Randall J Ruch
- Department of Cancer Biology, University of Toledo, Toledo, OH, United States
| | - Dayanidhi Raman
- Department of Cancer Biology, University of Toledo, Toledo, OH, United States
| |
Collapse
|
54
|
Sridharan S, Robeson M, Bastihalli-Tukaramrao D, Howard CM, Subramaniyan B, Tilley AMC, Tiwari AK, Raman D. Targeting of the Eukaryotic Translation Initiation Factor 4A Against Breast Cancer Stemness. Front Oncol 2019; 9:1311. [PMID: 31867270 PMCID: PMC6909344 DOI: 10.3389/fonc.2019.01311] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 11/11/2019] [Indexed: 12/14/2022] Open
Abstract
Breast cancer stem cells (BCSCs) are intrinsically chemoresistant and capable of self-renewal. Following chemotherapy, patients can develop minimal residual disease due to BCSCs which can repopulate into a relapsed tumor. Therefore, it is imperative to co-target BCSCs along with the bulk tumor cells to achieve therapeutic success and prevent recurrence. So, it is vital to identify actionable molecular targets against both BCSCs and bulk tumor cells. Previous findings from our lab and others have demonstrated that inhibition of the emerging drug target eIF4A with Rocaglamide A (RocA) was efficacious against triple-negative breast cancer cells (TNBC). RocA specifically targets the pool of eIF4A bound to the oncogenic mRNAs that requires its helicase activity for their translation. This property enables specific targeting of tumor cells. The efficacy of RocA against BCSCs is unknown. In this study, we postulated that eIF4A could be a vulnerable node in BCSCs. In order to test this, we generated a paclitaxel-resistant TNBC cell line which demonstrated an elevated level of eIF4A along with increased levels of cancer stemness markers (ALDH activity and CD44), pluripotency transcription factors (SOX2, OCT4, and NANOG) and drug transporters (ABCB1, ABCG2, and ABCC1). Furthermore, genetic ablation of eIF4A resulted in reduced expression of ALDH1A1, pluripotency transcription factors and drug transporters. This pointed out that eIF4A is likely associated with selected set of proteins that are critical to BCSCs, and hence targeting eIF4A may eliminate BCSCs. Therefore, we isolated BCSCs from two TNBC cell lines: MDA-Bone-Un and SUM-159PT. Following RocA treatment, the self-renewal ability of the BCSCs was significantly reduced as determined by the efficiency of the formation of primary and secondary mammospheres. This was accompanied by a reduction in the levels of NANOG, OCT4, and drug transporters. Exposure to RocA also induced cell death of the BCSCs as evaluated by DRAQ7 and cell viability assays. RocA treatment induced apoptosis with increased levels of cleaved caspase-3. Overall, we identified that RocA is effective in targeting BCSCs, and eIF4A is an actionable molecular target in both BCSCs and bulk tumor cells. Therefore, anti-eIF4A inhibitors could potentially be combined synergistically with existing chemo-, radio- and/or immunotherapies.
Collapse
Affiliation(s)
- Sangita Sridharan
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Megan Robeson
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Diwakar Bastihalli-Tukaramrao
- Department of Pharmacology & Experimental Therapeutics, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Cory M. Howard
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Boopathi Subramaniyan
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Augustus M. C. Tilley
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Amit K. Tiwari
- Department of Pharmacology & Experimental Therapeutics, University of Toledo Health Science Campus, Toledo, OH, United States
| | - Dayanidhi Raman
- Department of Cancer Biology, University of Toledo Health Science Campus, Toledo, OH, United States
- *Correspondence: Dayanidhi Raman
| |
Collapse
|
55
|
Spitz DR. Manipulations of Redox Metabolism for Enhancing Radiation Therapy Responses: A Historical Perspective and Novel Hypothesis. Semin Radiat Oncol 2019; 29:1-5. [PMID: 30573179 PMCID: PMC6709524 DOI: 10.1016/j.semradonc.2018.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Since the recognition during the 20th century that cancer cells demonstrated fundamental alterations in the regulation of oxidative and glycolytic metabolism, many basic as well as translational scientists have proposed that targeting metabolic differences in cancer versus normal cells could be exploited to improve cancer therapy outcomes. With the recognition that dysregulation of mitochondrial redox metabolism leads to the increased steady-state levels of superoxide and hydrogen peroxide which could contribute to both aging and cancer; radiation biologists have pursued many avenues of targeting oxidative metabolic pathways to both selectively radiosensitive cancer cells as well as protect normal tissues during cancer therapy. Recent advances in exploiting redox metabolism for improving radiochemotherapy both from a basic and translational science point of view are the focus of the papers in this current issue of Seminars in Radiation Oncology . The historical perspective underlying these areas of research as well as a unifying hypothesis for further advancing this research into clinical trials will be presented in this overview.
Collapse
Affiliation(s)
- Douglas R Spitz
- Free Radical and Radiation Biology Program, Department of Radiation Oncology, Free Radical Metabolism and Imaging Program, Holden Comprehensive Cancer Center, B180 Medical Laboratories, Carver College of Medicine, The University of Iowa, Iowa City, IA 52242..
| |
Collapse
|