Research ArticleExperimental Studies
Open Access

Recombinant Methioninase (rMETase) Synergistically Sensitizes Ivermectin-resistant MCF-7 Breast Cancer Cells 9.9 Fold to Low-dose Ivermectin

SEI MORINAGA, QINGHONG HAN, KOHEI MIZUTA, BYUNG MO KANG, CHIHIRO HOZUMI, MICHAEL BOUVET, NORIO YAMAMOTO, KATSUHIRO HAYASHI, HIROAKI KIMURA, SHINJI MIWA, KENTARO IGARASHI, TAKASHI HIGUCHI, HIROYUKI TSUCHIYA, SATORU DEMURA and ROBERT M. HOFFMAN
Anticancer Research February 2025, 45 (2) 451-455; DOI: https://doi.org/10.21873/anticanres.17434

Abstract

Background/Aim: Ivermectin is a widely-used anti-parasitic agent and has shown early promise as an anticancer agent. Recombinant methioninase (rMETase) is a methionine-depleting enzyme targeting the methionine addiction of cancer and has broad efficacy against all tested cancer types. However, the combination efficacy of ivermectin and rMETase on breast cancer cells remains unexplored. The present study aimed to determine the synergistic efficacy of ivermectin and rMETase on MCF-7 human breast cancer cells in vitro. Materials and Methods: The IC10 of ivermectin and IC50 of rMETase were determined on MCF-7 cells using the WST-8 reagent to measure cell viability in vitro. MCF-7 cells were treated with four groups: untreated control; ivermectin alone (4.89 μM, IC10); rMETase alone (2.75 U/ml, IC50); and a combination of ivermectin (4.89 μM) and rMETase (2.75 U/ml). Cell viability was assessed 72 hours after treatment with the WST-8 reagent. Results: Treatment with ivermectin (4.89 μM) did not significantly reduce the viability of MCF-7 cells. rMETase (2.75 U/ml) alone significantly reduced MCF-7 cell viability compared to the control group. The combination of ivermectin and rMETase resulted in a significantly greater reduction in cell viability than either agent alone, including a 9.9-fold greater efficacy than ivermectin alone, demonstrating synergistic efficacy (p<0.05). Conclusion: The combination of ivermectin and rMETase had synergistic efficacy against MCF-7 breast cancer cells in vitro. The present findings suggest that the combination of ivermectin and rMETase is a promising strategy for breast cancer requiring further preclinical and clinical evaluation.

Key Words:

Breast cancer remains the most common malignancy among women worldwide, accounting for a significant proportion of cancer-related morbidity and mortality (1). The development of effective therapeutic strategies targeting breast-cancer cells is critical for improving patient outcomes. The MCF-7 cell line, representing hormone-receptor-positive breast cancer, serves as a widely-used model for discovering novel therapeutic strategies (2).

Ivermectin, a macrocyclic lactone, is generally used as an antiparasitic agent. The Nobel prize was awarded to Satoshi Omura and William C. Campbell for its use against parasitic roundworms (3). Ivermectin has recently been found to have anticancer properties (4). Several studies have demonstrated its ability to induce cell-cycle arrest, apoptosis, and autophagy in various cancer cell lines, including breast cancer (5, 6).

Recombinant methioninase (rMETase), an enzyme that degrades extracellular methionine, targets the methionine addiction of cancer, termed the Hoffman effect (7, 8). Previous studies have demonstrated the efficacy of rMETase in preclinical models and patients with breast cancer (9-14).

We have previously shown synergy of ivermectin and rMETase in a pancreatic-cancer cell line (15). The present study investigated the efficacy of ivermectin and rMETase, individually and in combination, on MCF-7 human breast-cancer cells in vitro to determine their potential synergistic interaction.

Materials and Methods

Cell culture. MCF-7 breast-cancer cells were from the American Type Culture Collection (ATCC) (Manassas, VA, USA). The cells were cultured in Dulbecco’s modified Eagle’s medium (DMEM), supplemented with 10% fetal bovine serum (FBS) and 1 IU/ml penicillin/streptomycin (Corning, Corning, NY, USA) for all experiments.

Reagents. Ivermectin was from MedChemExpress (Monmouth Junction, NJ, USA). Recombinant methioninase (rMETase) was produced by AntiCancer Inc. by fermentation of recombinant E. coli transformed with the Pseudomonas putida methioninase gene, following a previously-established process (16).

Drug sensitivity assay 1: Determination of the IC10 of ivermectin and IC50 of rMETase on MCF-7 breast cancer cells. To determine the IC10 of ivermectin and IC50 of rMETase, MCF-7 cell viability was assessed using the WST-8 reagent (Dojindo Laboratory, Kumamoto, Japan). MCF-7 cells (3×103 cells per well) were seeded in 96-well plates containing 100 μl of DMEM per well. After incubation, rMETase at concentrations ranging from 0.5 U/ml to 8 U/ml or ivermectin at concentrations from 5 μM to 80 μM were added to the wells for 72 h. Following the 72 h incubation at 37°C, WST-8 solution (10 μl) was then added to each well, and the plates were incubated for an additional hour at 37°C. Absorbance at 450 nm, which correlates with cell viability, was measured using a microplate reader (SUNRISE, TECAN, Mannedorf, Switzerland). Drug-sensitivity curves were generated using Microsoft Excel (Microsoft, Redmond, WA, USA). The IC50 of rMETase and IC10 of ivermectin were calculated using ImageJ (National Institutes of Health, Bethesda, MD, USA). Each experiment was conducted twice in triplicate.

Drug sensitivity assay 2: Determination of synergy of ivermectin and rMETase on MCF-7 breast cancer cells. To determine the combined efficacy of ivermectin and rMETase on MCF-7 cells, the cells were seeded in 96-well plates at a density of 3×103 cells per well. After 24 h, the cells were treated as follows: control (DMEM); ivermectin alone (4.89 μM, [IC10]); rMETase alone (2.75 U/ml, [IC50]); and a combination of ivermectin (4.89 μM, [IC10]) and rMETase (2.75 U/ml, [IC50]). After 72 h of treatment, cell viability was measured as described above.

Statistical analysis. All statistical analyses were performed using EZR software (Jichi Medical University, Saitama, Japan). The Tukey–Kramer test was used to evaluate relationships between groups, with a significance level set at p≤0.05.

Results

Determination of IC10 of ivermectin alone and IC50 of rMETase alone on MCF-7 breast-cancer cells. The IC10 of ivermectin alone on MCF-7 cells was 4.89 μM. The IC50 for rMETase alone on MCF-7 cells was 2.75 U/ml (Figure 1).

Figure 1.
Figure 1.

Determination of the IC10 of ivermectin and IC50 of recombinant methioninase (rMETase) on MCF-7 breast cancer cells in vitro. A) IC10 of ivermectin on MCF-7 cells. B) IC50 of rMETase on MCF-7 cells. Please see Materials and Methods for details.

rMETase sensitized MCF-7 breast cancer cells to ivermectin. Compared to the control cells, treatment with ivermectin alone (4.89 μM, IC10) reduced the viability of MCF-7 cells by approximately 7.1 % (p>0.05), rMETase alone (2.75 U/ml, IC50) reduced the viability by 46.3 % (p<0.05), and the combination of ivermectin (4.89 μM, IC10) plus rMETase (2.75 U/ml, IC50) reduced the viability of MCF-7 cells by approximately 70.6%; p<0.05 compared to ivermectin alone or rMETase alone (Figure 2). Thus, rMETase incrased the sensitivity of MCF-7 cells to ivermectin 9.9 fold.

Figure 2.
Figure 2.

Recombinant methioninase (rMETase) synergistically sensitized MCF-7 breast cancer cells to low-dose ivermectin in vitro. Control; DMEM; ivermectin (4.89 μM, [IC10 for MCF-7 cells]); rMETase (2.75 U/ml, [IC50 for MCF-7 cells]); ivermectin (4.89 μM, [IC10 for MCF-7 cells]) plus rMETase (2.75 U/ml, [IC50 for MCF-7 cells]). Please see Materials and Methods for details.

Discussion

rMETase targets methionine addiction, a fundamental and general hallmark of cancer (7, 8). rMETase has demonstrated efficacy in preclinical models of all types of malignancies, including breast cancer (9-14, 17-18). Additionally, rMETase sensitized cancer cells to all major chemotherapy drugs (18-22). By targeting a global metabolic vulnerability of cancer cells, rMETase represents a promising strategy for enhancing the effectiveness of existing therapies.

The present study demonstrates, for the first time, the synergistic efficacy of ivermectin and rMETase against breast-cancer cells in vitro. Both rMETase and ivermectin arrest cancer cells during the S-phase of the cell cycle (23-27), which may account for their synergy.

We have previously shown that ivermectin and rMETase were synergistic against pancreatic-cancer cells (15). The present study demonstrated the synergy of ivermectin and rMETase on breast-cancer cells, even though the breast-cancer cells were not sensitive to ivermectin alone. Further studies are necessary in mouse cancer models and clinical settings to determine the mechanism underlying the synergistic efficacy of ivermectin and rMETase. Other studies have also shown surprising efficacy of ivermectin. In a study of cholangiocarcinoma (bile duct) cancer cells in vitro, ivermectin overcame gemcitabine resistance (25). Ivermectin also overcame paclitaxel resistance in non-small-cell lung-cancer cells by abolishing p-glycoprotein expression (26).

Methionine restriction is effective because it targets methionine addiction, the fundamental hallmark of cancer (7, 8, 27-44).

rMETase is showing clinical promise in breast cancer (11, 12), as well as pancreatic cancer (45, 46), rectal cancer (47, 48), prostate cancer (49-52) and leukemia (53), which can be combined with ivermectin for all cancer types.

Acknowledgements

This article is dedicated to the memory of A.R. Moossa, MD, Sun Lee, MD, Professor Gordon H. Sato, Professor Li Jiaxi, Masaki Kitajima, MD, Joseph R. Bertino, MD, Shigeo Yagi, PhD, J.A.R Mead, Ph.D., Eugene P. Frenkel, MD, Professor Lev Bergelson, Professor Sheldon Penman, Professor John R. Raper, Joseph Leighton, MD and John Mendelsohn, MD.

Footnotes

  • Authors’ Contributions

    SM, RMH, and QH designed the study. QH provided rMETase. SM performed experiments. SM was the major contributor to writing the article and RMH revised the article. KM, BMK, CH, MB, NY, KH, HK, SM, KI, TH, HT, and SD critically read the manuscript.

  • Conflicts of Interest

    The Authors have declared that there are no competing interests in relation to this study.

  • Received December 25, 2024.
  • Revision received January 12, 2025.
  • Accepted January 13, 2025.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY-NC-ND) 4.0 international license (https://creativecommons.org/licenses/by-nc-nd/4.0).

References

  1. ↵
    1. Arnold M,
    2. Morgan E,
    3. Rumgay H,
    4. Mafra A,
    5. Singh D,
    6. Laversanne M,
    7. Vignat J,
    8. Gralow JR,
    9. Cardoso F,
    10. Siesling S,
    11. Soerjomataram I
    : Current and future burden of breast cancer: Global statistics for 2020 and 2040. Breast 66: 15-23, 2022. DOI: 10.1016/j.breast.2022.08.010
    OpenUrlCrossRefPubMed
  2. ↵
    1. Comşa Ş,
    2. Cîmpean AM,
    3. Raica M
    : The story of MCF-7 breast cancer cell line: 40 years of experience in research. Anticancer Res 35: 3147-3154, 2015.
    OpenUrlAbstract/FREE Full Text
  3. ↵
    1. Van Voorhis WC,
    2. Hooft van Huijsduijnen R,
    3. Wells TN
    : Profile of William C. Campbell, Satoshi Ōmura, and Youyou Tu, 2015 Nobel Laureates in Physiology or Medicine. Proc Natl Acad Sci USA 112(52): 15773-15776, 2015. DOI: 10.1073/pnas.1520952112
    OpenUrlFREE Full Text
  4. ↵
    1. Tang M,
    2. Hu X,
    3. Wang Y,
    4. Yao X,
    5. Zhang W,
    6. Yu C,
    7. Cheng F,
    8. Li J,
    9. Fang Q
    : Ivermectin, a potential anticancer drug derived from an antiparasitic drug. Pharmacol Res 163: 105207, 2021. DOI: 10.1016/j.phrs.2020.105207
    OpenUrlCrossRefPubMed
  5. ↵
    1. Wang K,
    2. Gao W,
    3. Dou Q,
    4. Chen H,
    5. Li Q,
    6. Nice EC,
    7. Huang C
    : Ivermectin induces PAK1-mediated cytostatic autophagy in breast cancer. Autophagy 12(12): 2498-2499, 2016. DOI: 10.1080/15548627.2016.1231494
    OpenUrlCrossRefPubMed
  6. ↵
    1. Dominguez-Gomez G,
    2. Chavez-Blanco A,
    3. Medina-Franco JL,
    4. Saldivar-Gonzalez F,
    5. Flores-Torrontegui Y,
    6. Juarez M,
    7. Díaz-Chávez J,
    8. Gonzalez-Fierro A,
    9. Dueñas-González A
    : Ivermectin as an inhibitor of cancer stem-like cells. Mol Med Rep 17: 3397-3403, 2018. DOI: 10.3892/mmr.2017.8231
    OpenUrlCrossRef
  7. ↵
    1. Hoffman RM
    : Development of recombinant methioninase to target the general cancer-specific metabolic defect of methionine dependence: a 40-year odyssey. Expert Opin Biol Ther 15(1): 21-31, 2015. DOI: 10.1517/14712598.2015.963050
    OpenUrlCrossRefPubMed
  8. ↵
    1. Hoffman RM,
    2. Erbe RW
    : High in vivo rates of methionine biosynthesis in transformed human and malignant rat cells auxotrophic for methionine. Proc Natl Acad Sci USA 73(5): 1523-1527, 1976. DOI: 10.1073/pnas.73.5.1523
    OpenUrlAbstract/FREE Full Text
  9. ↵
    1. Sugisawa N,
    2. Hamada K,
    3. Han Q,
    4. Yamamoto J,
    5. Sun Y,
    6. Nishino H,
    7. Kawaguchi K,
    8. Bouvet M,
    9. Unno M,
    10. Hoffman RM
    : Adjuvant oral recombinant methioninase inhibits lung metastasis in a surgical breast-cancer orthotopic syngeneic model. Anticancer Res 40(9): 4869-4874, 2020. DOI: 10.21873/anticanres.14489
    OpenUrlAbstract/FREE Full Text
    1. Lim HI,
    2. Yamamoto J,
    3. Han Q,
    4. Sun YU,
    5. Nishino H,
    6. Tashiro Y,
    7. Sugisawa N,
    8. Tan Y,
    9. Choi HJ,
    10. Nam SJ,
    11. Bouvet M,
    12. Hoffman RM
    : Response of triple-negative breast cancer liver metastasis to oral recombinant methioninase in a patient-derived orthotopic xenograft (PDOX) model. In Vivo 34(6): 3163-3169, 2020. DOI: 10.21873/invivo.12151
    OpenUrlAbstract/FREE Full Text
  11. ↵
    1. Sato M,
    2. Han Q,
    3. Mori R,
    4. Mizuta K,
    5. Kang BM,
    6. Morinaga S,
    7. Kobayashi N,
    8. Ichikawa Y,
    9. Nakajima A,
    10. Hoffman RM
    : Reduction of tumor biomarkers from very high to normal and extensive metastatic lesions to undetectability in a patient with stage IV HER2-positive breast cancer treated with low-dose trastuzumab deruxtecan in combination with oral recombinant methioninase and a low-methionine diet. Anticancer Res 44(4): 1499-1504, 2024. DOI: 10.21873/anticanres.16946
    OpenUrlAbstract/FREE Full Text
  12. ↵
    1. Kubota Y,
    2. Han Q,
    3. Masaki N,
    4. Hozumi C,
    5. Hamada K,
    6. Aoki Y,
    7. Obara K,
    8. Tsunoda T,
    9. Hoffman RM
    : Elimination of axillary-lymph-node metastases in a patient with invasive lobular breast cancer treated by first-line neo-adjuvant chemotherapy combined with methionine restriction. Anticancer Res 42(12): 5819-5823, 2022. DOI: 10.21873/anticanres.16089
    OpenUrlAbstract/FREE Full Text
    1. Lim HI,
    2. Sun YU,
    3. Han Q,
    4. Yamamoto J,
    5. Hoffman RM
    : Efficacy of oral recombinant methioninase and eribulin on a PDOX model of triple-negative breast cancer (TNBC) liver metastasis. In Vivo 35(5): 2531-2534, 2021. DOI: 10.21873/invivo.12534
    OpenUrlAbstract/FREE Full Text
  14. ↵
    1. Lim HI,
    2. Hamada K,
    3. Yamamoto J,
    4. Han Q,
    5. Tan Y,
    6. Choi HJ,
    7. Nam SJ,
    8. Bouvet M,
    9. Hoffman RM
    : Oral methioninase inhibits recurrence in a PDOX mouse model of aggressive triple-negative breast cancer. In Vivo 34(5): 2281-2286, 2020. DOI: 10.21873/invivo.12039
    OpenUrlAbstract/FREE Full Text
  15. ↵
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Bouvet M,
    6. Yamamoto N,
    7. Hayashi K,
    8. Kimura H,
    9. Miwa S,
    10. Igarashi K,
    11. Higuchi T,
    12. Tsuchiya H,
    13. Demura S,
    14. Hoffman RM
    : Ivermectin combined with recombinant methioninase (rMETase) synergistically eradicates MiaPaCa-2 pancreatic cancer cells. Anticancer Res 45(1): 97-103, 2025. DOI: 10.21873/anticanres.17396
    OpenUrlAbstract/FREE Full Text
  16. ↵
    1. Tan Y,
    2. Xu M,
    3. Tan X,
    4. Tan X,
    5. Wang X,
    6. Saikawa Y,
    7. Nagahama T,
    8. Sun X,
    9. Lenz M,
    10. Hoffman RM
    : Overexpression and large-scale production of recombinantl-methionine-α-deamino-γ-mercapto-methane-lyase for novel anticancer therapy. Protein Expr Purif 9(2): 233-245, 1997. DOI: 10.1006/prep.1996.0700
    OpenUrlCrossRefPubMed
  17. ↵
    1. Kubota Y,
    2. Han Q,
    3. Morinaga S,
    4. Mizuta K,
    5. Bouvet M,
    6. Tsunoda T,
    7. Hoffman RM
    : Recombinant-methioninase-producing Escherichia coli instilled in the microbiome inhibits triple-negative breast cancer in an orthotopic cell-line mouse model. Cancer Diagn Progn 3(6): 649-654, 2023. DOI: 10.21873/cdp.10267
    OpenUrlCrossRefPubMed
  18. ↵
    1. Kubota Y,
    2. Han Q,
    3. Aoki Y,
    4. Masaki N,
    5. Obara K,
    6. Hamada K,
    7. Hozumi C,
    8. Wong ACW,
    9. Bouvet M,
    10. Tsunoda T,
    11. Hoffman RM
    : Synergy of combining methionine restriction and chemotherapy: the disruptive next generation of cancer treatment. Cancer Diagn Progn 3(3): 272-281, 2023. DOI: 10.21873/cdp.10212
    OpenUrlCrossRefPubMed
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Sato M,
    6. Bouvet M,
    7. Yamamoto N,
    8. Hayashi K,
    9. Kimura H,
    10. Miwa S,
    11. Igarashi K,
    12. Higuchi T,
    13. Tsuchiya H,
    14. Demura S,
    15. Hoffman RM
    : Recombinant methioninase increases eribulin efficacy 16-fold in highly eribulin-resistant HT1080 fibrosarcoma cells, demonstrating potential to overcome the clinical challenge of drug-resistant soft-tissue sarcoma. Anticancer Res 44(9): 3777-3783, 2024. DOI: 10.21873/anticanres.17202
    OpenUrlAbstract/FREE Full Text
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Sato M,
    6. Bouvet M,
    7. Yamamoto N,
    8. Hayashi K,
    9. Kimura H,
    10. Miwa S,
    11. Igarashi K,
    12. Higuchi T,
    13. Tsuchiya H,
    14. Demura S,
    15. Hoffman RM
    : Overcoming high trabectedin resistance of soft-tissue sarcoma with recombinant methioninase: a potential solution of a recalcitrant clinical problem. Anticancer Res 44(9): 3785-3791, 2024. DOI: 10.21873/anticanres.17203
    OpenUrlAbstract/FREE Full Text
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Bouvet M,
    6. Yamamoto N,
    7. Hayashi K,
    8. Kimura H,
    9. Miwa S,
    10. Igarashi K,
    11. Higuchi T,
    12. Tsuchiya H,
    13. Demura S,
    14. Hoffman RM
    : Recombinant methioninase synergistically reverses high-docetaxel resistance developed in osteosarcoma cells. Anticancer Res 44(11): 4773-4778, 2024. DOI: 10.21873/anticanres.17303
    OpenUrlAbstract/FREE Full Text
  22. ↵
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Bouvet M,
    6. Yamamoto N,
    7. Hayashi K,
    8. Kimura H,
    9. Miwa S,
    10. Igarashi K,
    11. Higuchi T,
    12. Tsuchiya H,
    13. Demura S,
    14. Hoffman RM
    : Selective synergy of recombinant methioninase plus docetaxel against docetaxel-resistant and -sensitive fibrosarcoma cells compared to normal fibroblasts. Anticancer Res 44(12): 5207-5213, 2024. DOI: 10.21873/anticanres.17347
    OpenUrlAbstract/FREE Full Text
  23. ↵
    1. Zhang P,
    2. Zhang Y,
    3. Liu K,
    4. Liu B,
    5. Xu W,
    6. Gao J,
    7. Ding L,
    8. Tao L
    : Ivermectin induces cell cycle arrest and apoptosis of HeLa cells via mitochondrial pathway. Cell Prolif 52(2): e12543, 2019. DOI: 10.1111/cpr.12543
    OpenUrlCrossRefPubMed
    1. Yano S,
    2. Li S,
    3. Han Q,
    4. Tan Y,
    5. Bouvet M,
    6. Fujiwara T,
    7. Hoffman RM
    : Selective methioninase-induced trap of cancer cells in S/G2 phase visualized by FUCCI imaging confers chemosensitivity. Oncotarget 5(18): 8729-8736, 2014. DOI: 10.18632/oncotarget.2369
    OpenUrlCrossRefPubMed
  25. ↵
    1. Intuyod K,
    2. Hahnvajanawong C,
    3. Pinlaor P,
    4. Pinlaor S
    : Anti-parasitic drug ivermectin exhibits potent anticancer activity against gemcitabine-resistant cholangiocarcinoma in vitro. Anticancer Res 39(9): 4837-4843, 2019. DOI: 10.21873/anticanres.13669
    OpenUrlAbstract/FREE Full Text
  26. ↵
    1. Hayashi A,
    2. Kamio K,
    3. Miyanaga A,
    4. Yoshida K,
    5. Noro R,
    6. Matsuda K,
    7. Tozuka T,
    8. Omori M,
    9. Hirao M,
    10. Fukuizumi A,
    11. Hisakane K,
    12. Takeuchi S,
    13. Matsumoto M,
    14. Kasahara K,
    15. Amano T,
    16. Honda K,
    17. Seike M
    : Ivermectin enhances paclitaxel efficacy by overcoming resistance through modulation of ABCB1 in non-small cell lung cancer. Anticancer Res 44(12): 5271-5282, 2024. DOI: 10.21873/anticanres.17355
    OpenUrlAbstract/FREE Full Text
  27. ↵
    1. Hoffman RM,
    2. Jacobsen SJ
    : Reversible growth arrest in simian virus 40-transformed human fibroblasts. Proc Natl Acad Sci U S A 77(12): 7306-7310, 1980. DOI: 10.1073/pnas.77.12.7306
    OpenUrlAbstract/FREE Full Text
    1. Wang Z,
    2. Yip LY,
    3. Lee JHJ,
    4. Wu Z,
    5. Chew HY,
    6. Chong PKW,
    7. Teo CC,
    8. Ang HY,
    9. Peh KLE,
    10. Yuan J,
    11. Ma S,
    12. Choo LSK,
    13. Basri N,
    14. Jiang X,
    15. Yu Q,
    16. Hillmer AM,
    17. Lim WT,
    18. Lim TKH,
    19. Takano A,
    20. Tan EH,
    21. Tan DSW,
    22. Ho YS,
    23. Lim B,
    24. Tam WL
    : Methionine is a metabolic dependency of tumor-initiating cells. Nat Med 25(5): 825-837, 2019. DOI: 10.1038/s41591-019-0423-5
    OpenUrlCrossRefPubMed
    1. Coalson DW,
    2. Mecham JO,
    3. Stern PH,
    4. Hoffman RM
    : Reduced availability of endogenously synthesized methionine for S-adenosylmethionine formation in methionine-dependent cancer cells. Proc Natl Acad Sci USA 79(14): 4248-4251, 1982. DOI: 10.1073/pnas.79.14.4248
    OpenUrlAbstract/FREE Full Text
    1. Stern PH,
    2. Mecham JO,
    3. Wallace CD,
    4. Hoffman RM
    : Reduced free-methionine in methionine-dependent SV40-transformed human fibroblasts synthesizing apparently normal amounts of methionine. J Cell Physiol 117(1): 9-14, 1983. DOI: 10.1002/jcp.1041170103
    OpenUrlCrossRefPubMed
    1. Aoki Y,
    2. Han Q,
    3. Tome Y,
    4. Yamamoto J,
    5. Kubota Y,
    6. Masaki N,
    7. Obara K,
    8. Hamada K,
    9. Wang JD,
    10. Inubushi S,
    11. Bouvet M,
    12. Clarke SG,
    13. Nishida K,
    14. Hoffman RM
    : Reversion of methionine addiction of osteosarcoma cells to methionine independence results in loss of malignancy, modulation of the epithelial-mesenchymal phenotype and alteration of histone-H3 lysine-methylation. Front Oncol 12: 1009548, 2022. DOI: 10.3389/fonc.2022.1009548
    OpenUrlCrossRefPubMed
    1. Yamamoto J,
    2. Inubushi S,
    3. Han Q,
    4. Tashiro Y,
    5. Sugisawa N,
    6. Hamada K,
    7. Aoki Y,
    8. Miyake K,
    9. Matsuyama R,
    10. Bouvet M,
    11. Clarke SG,
    12. Endo I,
    13. Hoffman RM
    : Linkage of methionine addiction, histone lysine hypermethylation, and malignancy. iScience 25(4): 104162, 2022. DOI: 10.1016/j.isci.2022.104162
    OpenUrlCrossRefPubMed
    1. Yamamoto J,
    2. Aoki Y,
    3. Inubushi S,
    4. Han Q,
    5. Hamada K,
    6. Tashiro Y,
    7. Miyake K,
    8. Matsuyama R,
    9. Bouvet M,
    10. Clarke SG,
    11. Endo I,
    12. Hoffman RM
    : Extent and instability of trimethylation of histone H3 lysine increases with degree of malignancy and methionine addiction. Cancer Genomics Proteomics 19(1): 12-18, 2022. DOI: 10.21873/cgp.20299
    OpenUrlAbstract/FREE Full Text
    1. Hoffman RM,
    2. Jacobsen SJ,
    3. Erbe RW
    : Reversion to methionine independence in simian virus 40-transformed human and malignant rat fibroblasts is associated with altered ploidy and altered properties of transformation. Proc Natl Acad Sci 76(3): 1313-1317, 1979. DOI: 10.1073/pnas.76.3.1313
    OpenUrlAbstract/FREE Full Text
    1. Yamamoto J,
    2. Aoki Y,
    3. Han Q,
    4. Sugisawa N,
    5. Sun YU,
    6. Hamada K,
    7. Nishino H,
    8. Inubushi S,
    9. Miyake K,
    10. Matsuyama R,
    11. Bouvet M,
    12. Endo I,
    13. Hoffman RM
    : Reversion from methionine addiction to methionine independence results in loss of tumorigenic potential of highly-malignant lung-cancer cells. Anticancer Res 41(2): 641-643, 2021. DOI: 10.21873/anticanres.14815
    OpenUrlAbstract/FREE Full Text
    1. Hoffman RM
    : Altered methionine metabolism, DNA methylation and oncogene expression in carcinogenesis. A review and synthesis. Biochim Biophys Acta 738: 49-87, 1984. DOI: 10.1016/0304-419x(84)90019-2
    OpenUrlCrossRefPubMed
    1. Abo Qoura L,
    2. Balakin KV,
    3. Hoffman RM,
    4. Pokrovsky VS
    : The potential of methioninase for cancer treatment. Biochim Biophys Acta Rev Cancer 1879(4): 189122, 2024. DOI: 10.1016/j.bbcan.2024.189122
    OpenUrlCrossRef
    1. Ghergurovich JM,
    2. Xu X,
    3. Wang JZ,
    4. Yang L,
    5. Ryseck RP,
    6. Wang L,
    7. Rabinowitz JD
    : Methionine synthase supports tumour tetrahydrofolate pools. Nat Metab 3(11): 1512-1520, 2021. DOI: 10.1038/s42255-021-00465-w
    OpenUrlCrossRefPubMed
    1. Sullivan MR,
    2. Darnell AM,
    3. Reilly MF,
    4. Kunchok T,
    5. Joesch-Cohen L,
    6. Rosenberg D,
    7. Ali A,
    8. Rees MG,
    9. Roth JA,
    10. Lewis CA,
    11. Vander Heiden MG
    : Methionine synthase is essential for cancer cell proliferation in physiological folate environments. Nat Metab 3(11): 1500-1511, 2021. DOI: 10.1038/s42255-021-00486-5
    OpenUrlCrossRef
    1. Mecham JO,
    2. Rowitch D,
    3. Wallace CD,
    4. Stern PH,
    5. Hoffman RM
    : The metabolic defect of methionine dependence occurs frequently in human tumor cell lines. Biochem Biophys Res Commun 117(2): 429-34, 1983. DOI: 10.1016/0006-291x(83)91218-4
    OpenUrlCrossRefPubMed
    1. Stern PH,
    2. Wallace CD,
    3. Hoffman RM
    : Altered methionine metabolism occurs in all members of a set of diverse human tumor cell lines. J Cell Physiol 119(1): 29-34, 1984. DOI: 10.1002/jcp.1041190106
    OpenUrlCrossRefPubMed
    1. Tan Y,
    2. Xu M,
    3. Hoffman RM
    : Broad selective efficacy of recombinant methioninase and polyethylene glycol-modified recombinant methioninase on cancer cells In Vitro. Anticancer Res 30(4): 1041-6, 2010
    OpenUrlAbstract/FREE Full Text
    1. Yamamoto J,
    2. Han Q,
    3. Inubushi S,
    4. Sugisawa N,
    5. Hamada K,
    6. Nishino H,
    7. Miyake K,
    8. Kumamoto T,
    9. Matsuyama R,
    10. Bouvet M,
    11. Endo I,
    12. Hoffman RM
    : Histone methylation status of H3K4me3 and H3K9me3 under methionine restriction is unstable in methionine-addicted cancer cells, but stable in normal cells. Biochem Biophys Res Commun 533(4): 1034-1038, 2020. DOI: 10.1016/j.bbrc.2020.09.108
    OpenUrlCrossRefPubMed
  44. ↵
    1. Stern PH,
    2. Hoffman RM
    : Enhanced in vitro selective toxicity of chemotherapeutic agents for human cancer cells based on a metabolic defect. J Natl Cancer Inst 76(4): 629-639, 1986. DOI: 10.1093/jnci/76.4.629
    OpenUrlCrossRefPubMed
  45. ↵
    1. Sato M,
    2. Han Q,
    3. Hozumi C,
    4. Kujiraoka H,
    5. Mizuta K,
    6. Morinaga S,
    7. Kang BM,
    8. Kobayashi N,
    9. Ichikawa Y,
    10. Nakajima A,
    11. Hoffman RM
    : First-line chemotherapy in combination with oral recombinant methioninase and a low-methionine diet for a stage IV inoperable pancreatic-cancer patient resulted in 40% tumor reduction and an 86% CA19-9 biomarker decrease. Anticancer Res 44(9): 3885-3889, 2024. DOI: 10.21873/anticanres.17215
    OpenUrlAbstract/FREE Full Text
  46. ↵
    1. Kubota Y,
    2. Han Q,
    3. Hozumi C,
    4. Masaki N,
    5. Yamamoto J,
    6. Aoki Y,
    7. Tsunoda T,
    8. Hoffman RM
    : Stage IV pancreatic cancer patient treated with FOLFIRINOX combined with oral methioninase: a highly-rare case with long-term stable disease. Anticancer Res 42(5): 2567-2572, 2022. DOI: 10.21873/anticanres.15734
    OpenUrlAbstract/FREE Full Text
  47. ↵
    1. Kubota Y,
    2. Han Q,
    3. Morinaga S,
    4. Tsunoda T,
    5. Hoffman RM
    : Rapid reduction of CEA and stable metastasis in an NRAS-mutant rectal-cancer patient treated with FOLFIRI and bevacizumab combined with oral recombinant methioninase and a low-methionine diet upon metastatic recurrence after FOLFIRI and bevacizumab treatment alone. In Vivo 37(5): 2134-2138, 2023. DOI: 10.21873/invivo.13310
    OpenUrlAbstract/FREE Full Text
  48. ↵
    1. Kubota Y,
    2. Han Q,
    3. Hamada K,
    4. Aoki Y,
    5. Masaki N,
    6. Obara K,
    7. Tsunoda T,
    8. Hoffman RM
    : Long-term stable disease in a rectal-cancer patient treated by methionine restriction with oral recombinant methioninase and a low-methionine diet. Anticancer Res 42(8): 3857-3861, 2022. DOI: 10.21873/anticanres.15877
    OpenUrlAbstract/FREE Full Text
  49. ↵
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Yamamoto N,
    6. Hayashi K,
    7. Kimura H,
    8. Miwa S,
    9. Igarashi K,
    10. Higuchi T,
    11. Tsuchiya H,
    12. Demura S,
    13. Hoffman RM
    : Prostate cancer patient with lymph-node metastasis treated only with methionine restriction has stable disease for two years demonstrated with PET/CT and PSMA-PET scanning and PSA testing. Cancer Diagn Progn 5(1): 27-31, 2025. DOI: 10.21873/cdp.10408
    OpenUrlCrossRefPubMed
    1. Han Q,
    2. Hoffman RM
    : Chronic treatment of an advanced prostate-cancer patient with oral methioninase resulted in long-term stabilization of rapidly rising PSA levels. In Vivo 35(4): 2171-2176, 2021. DOI: 10.21873/invivo.12488
    OpenUrlAbstract/FREE Full Text
    1. Han Q,
    2. Hoffman RM
    : Lowering and stabilizing PSA levels in advanced-prostate cancer patients with oral methioninase. Anticancer Res 41(4): 1921-1926, 2021. DOI: 10.21873/anticanres.14958
    OpenUrlAbstract/FREE Full Text
  52. ↵
    1. Han Q,
    2. Tan Y,
    3. Hoffman RM
    : Oral dosing of recombinant methioninase is associated with a 70% drop in PSA in a patient with bone-metastatic prostate cancer and 50% reduction in circulating methionine in a high-stage ovarian cancer patient. Anticancer Res 40(5): 2813-2819, 2020. DOI: 10.21873/anticanres.14254
    OpenUrlAbstract/FREE Full Text
  53. ↵
    1. Morinaga S,
    2. Han Q,
    3. Mizuta K,
    4. Kang BM,
    5. Yamamoto N,
    6. Hayashi K,
    7. Kimura H,
    8. Miwa S,
    9. Igarashi K,
    10. Higuchi T,
    11. Tsuchiya H,
    12. Demura S,
    13. Hoffman RM
    : Complete response (CR) in a previously-progressing chronic lymphocytic leukemia (CLL) patient treated with methionine restriction in combination with first-line chemotherapy. Cancer Diagn Progn 5(1): 21-26, 2025. DOI: 10.21873/cdp.10407
    OpenUrlCrossRefPubMed
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Recombinant Methioninase (rMETase) Synergistically Sensitizes Ivermectin-resistant MCF-7 Breast Cancer Cells 9.9 Fold to Low-dose Ivermectin
SEI MORINAGA, QINGHONG HAN, KOHEI MIZUTA, BYUNG MO KANG, CHIHIRO HOZUMI, MICHAEL BOUVET, NORIO YAMAMOTO, KATSUHIRO HAYASHI, HIROAKI KIMURA, SHINJI MIWA, KENTARO IGARASHI, TAKASHI HIGUCHI, HIROYUKI TSUCHIYA, SATORU DEMURA, ROBERT M. HOFFMAN
Anticancer Research Feb 2025, 45 (2) 451-455; DOI: 10.21873/anticanres.17434
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