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Background/Aim: Androgen-independent prostate cancer (AIPC) is resistant to androgen-depletion therapy and is a recalcitrant disease. Docetaxel is the first-line treatment for AIPC, but has limited efficacy and severe side-effects. All cancers are methionine-addicted, which is termed the Hoffman effect. Recombinant methioninase (rMETase) targets methionine addiction. The purpose of the present study was to determine if the combination of docetaxel and rMETase is effective for AIPC. Materials and Methods: The half-maximal inhibitory concentrations (IC50) of docetaxel and rMETase alone were determined for the human AIPC cell line PC-3 and Hs27 normal human fibroblasts in vitro. The synergistic efficacy for PC-3 and Hs27 using the combination of docetaxel and rMETase at their IC50s for PC-3 was determined. Results: The IC50 of docetaxel for PC-3 and for Hs27 was 0.72 nM and 0.94 nM, respectively. The IC50 of rMETase for PC-3 and for Hs27 was 0.67 U/ml and 0.76 U/ml, respectively. The combination of docetaxel and rMETase was synergistic for PC-3 but not Hs27 cells. Conclusion: The combination of a relatively low concentration of docetaxel and rMETase was synergistic and effective for AIPC. The present results also suggest that the effective concentration of docetaxel can be reduced by using rMETase, which may reduce toxicity. The present results also suggest the future clinical potential of the combination of docetaxel and rMETase for AIPC.
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Background/Aim: Rapamycin inhibits the mTOR protein kinase. Methioninase (rMETase), by degrading methionine, targets the methionine addiction of cancer cells and has been shown to improve the efficacy of chemotherapy drugs, reducing their effective doses. Our previous study demonstrated that rapamycin and rMETase work synergistically against colorectal-cancer cells, but not on normal cells, when administered simultaneously in vitro. In the present study, we aimed to further our previous findings by exploring whether synergy exists between rapamycin and rMETase when used sequentially against HCT-116 colorectal-carcinoma cells, compared to simultaneous administration, in vitro. Materials and Methods: The half-maximal inhibitory concentrations (IC50) of rapamycin alone and rMETase alone against the HCT-116 human colorectal-cancer cell line were previously determined using the CCK-8 cell viability assay (11). We then examined the efficacy of rapamycin and rMETase, both at their IC50, administered simultaneously or sequentially on the HCT-116 cell line, with rapamycin administered before rMETase and vice versa. Results: The IC50 for rapamycin and rMETase, determined from previous experiments (11), was 1.38 nM and 0.39 U/ml, respectively, of HCT-116 cells. When rMETase was administered four days before rapamycin, both at the IC50, there was a 30.46% inhibition of HCT-116 cells. When rapamycin was administered four days before rMETase, both at the IC50, there was an inhibition of 41.13%. When both rapamycin and rMETase were simultaneously administered, both at the IC50, there was a 71.03% inhibition. Conclusion: Rapamycin and rMETase have synergistic efficacy against colorectal-cancer cells in vitro when administered simultaneously, but not sequentially.
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BACKGROUND/AIM: Doxorubicin is first-line therapy for soft-tissue sarcoma, but patients can develop resistance which is usually fatal. As a novel therapeutic strategy, the present study aimed to determine the synergy of recombinant methioninase (rMETase) and doxorubicin against HT1080 fibrosarcoma cells compared to Hs27 normal fibroblasts, and rMETase efficacy against doxorubicin-resistant HT1080 cells in vitro. MATERIALS AND METHODS: The 50% inhibitory concentrations (IC50) of doxorubicin and rMETase, as well as their combination efficacy, against HT1080 human fibrosarcoma cells, Hs27 normal human fibroblasts and doxorubicin-resistant HT1080 (DR-HT1080) cells were determined. Dual-color HT1080 cells which expressed red fluorescent protein (RFP) in the cytoplasm and green fluorescent protein (GFP) in the nuclei were used to visualize nuclear fragmentation during treatment. Nuclear fragmentation was observed with an IX71 fluorescence microscope. RESULTS: The IC50 for doxorubicin was 3.3 µM for HT1080 cells, 12.4 µM for DR-HT1080 cells, and 7.25 µM for Hs27 cells. The IC50 for rMETase was 0.75 U/ml for HT1080 cells, 0.42 U/ml for DR-HT1080 cells, and 0.93 U/ml for Hs27 cells. The combination of rMETase and doxorubicin was synergistic against fibrosarcoma cells but not against normal fibroblasts. The combination of doxorubicin plus rMETase also caused more fragmented nuclei than either treatment alone in HT1080 cells. rMETase alone was highly effective against the DR-HT1080 cells as well as the parental HT1080 cells. CONCLUSION: The present results indicate the future clinical potential of rMETase in combination with doxorubicin for fibrosarcoma, including doxorubicin-resistant fibrosarcoma.
Sujet(s)
Carbon-sulfur lyases , Doxorubicine , Résistance aux médicaments antinéoplasiques , Synergie des médicaments , Fibrosarcome , Protéines recombinantes , Humains , Doxorubicine/pharmacologie , Fibrosarcome/traitement médicamenteux , Fibrosarcome/anatomopathologie , Fibrosarcome/métabolisme , Carbon-sulfur lyases/pharmacologie , Résistance aux médicaments antinéoplasiques/effets des médicaments et des substances chimiques , Lignée cellulaire tumorale , Protéines recombinantes/pharmacologie , Antibiotiques antinéoplasiques/pharmacologie , Fibroblastes/effets des médicaments et des substances chimiques , Fibroblastes/métabolismeRÉSUMÉ
BACKGROUND/AIM: BRCA1/2 mutations in breast cancer cells impair homologous recombination and promote alternative end joining (Alt-EJ) for DNA-damage repair. DNA polymerase theta, encoded by POLQ, plays a crucial role in Alt-EJ, making it a potential therapeutic target, particularly in BRCA1/2-mutant cancers. Methionine restriction is a promising approach to target cancer cells due to their addiction to this amino acid. The present study investigated the expression of POLQ in BRCA1/2 wild-type and BRCA1-mutant breast cancer cells under methionine restriction. MATERIALS AND METHODS: POLQ mRNA expression was measured using qRT-PCR in BRCA1/2 wild-type (MDA-MB-231) and BRCA1- mutant (HCC1937 and MDA-MB-436) breast-cancer cells under normal, or serum-restricted, or serum- and methionine-restricted conditions. RESULTS: Compared to BRCA1/2 wild-type cells, BRCA1-mutant cells displayed significantly higher basal POLQ expression in normal medium. Methionine restriction further increased POLQ expression in the BRCA1-mutant cells but decreased it in the BRCA1/2 wild-type cells. CONCLUSION: The present findings suggest that methionine restriction showed differential effects on POLQ expression, potentially impacting Alt-EJ activity, in BRCA1/2 wild-type and BRCA1-mutant breast-cancer cells. Further investigation is needed to explore the potential of combining methionine restriction with DNA-repair inhibitors, such as PARP inhibitors, to overcome drug resistance in BRCA1/2 mutant cancers.
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Protéine BRCA1 , Tumeurs du sein , , Méthionine , Mutation , Humains , Méthionine/métabolisme , Tumeurs du sein/génétique , Tumeurs du sein/anatomopathologie , Tumeurs du sein/métabolisme , Femelle , Protéine BRCA1/génétique , Protéine BRCA1/métabolisme , DNA-directed DNA polymerase/métabolisme , DNA-directed DNA polymerase/génétique , Réparation de l'ADN , Lignée cellulaire tumorale , Régulation de l'expression des gènes tumoraux , Protéine BRCA2/génétique , Protéine BRCA2/métabolismeRÉSUMÉ
BACKGROUND/AIM: The alkylating agent trabectedin, which binds the minor groove of DNA, is second-line therapy for soft-tissue sarcoma but has only moderate efficacy. The aim of the present study was to determine the synergistic efficacy of recombinant methioninase (rMETase) and trabectedin on fibrosarcoma cells in vitro, compared with normal fibroblasts. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells expressing green fluorescent protein (GFP) in the nucleus and red fluorescent protein (RFP) in the cytoplasm and Hs27 normal human fibroblasts, were used. Each cell line was cultured in vitro and divided into four groups: no-treatment control; trabectedin treated; rMETase treated; and trabectedin plus rMETase treated. The dual-color HT1080 cells were used to quantitate nuclear fragmentation in each treatment group. RESULTS: The combination of rMETase and trabectedin was highly synergistic to decrease HT1080 cell viability. In contrast, there was no synergy on Hs27 cells. Moreover, nuclear fragmentation occurred synergistically with the combination of trabectedin and rMETase on dual-color HT1080 cells. CONCLUSION: The combination treatment of trabectedin plus rMETase was highly synergistic on fibrosarcoma cells in vitro suggesting that the combination can improve the outcome of trabectedin alone in future clinical studies. The lack of synergy of rMETase and trabectedin on normal fibroblasts suggests the combination is not toxic to normal cells. Synergy of the two drugs may be due to the high rate of nuclear fragmentation on treated HT1080 cells, and the late-S/G2 cell-cycle block of cancer cells by rMETase, which is a target for trabectedin. The results of the present study suggest the future clinical potential of the combination of rMETase and trabectedin for soft-tissue sarcoma.
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Carbon-sulfur lyases , Survie cellulaire , Dioxoles , Synergie des médicaments , Fibroblastes , Fibrosarcome , Tétrahydroisoquinoléines , Trabectédine , Humains , Fibrosarcome/traitement médicamenteux , Fibrosarcome/anatomopathologie , Fibrosarcome/métabolisme , Fibroblastes/effets des médicaments et des substances chimiques , Fibroblastes/métabolisme , Trabectédine/pharmacologie , Carbon-sulfur lyases/pharmacologie , Carbon-sulfur lyases/administration et posologie , Tétrahydroisoquinoléines/pharmacologie , Dioxoles/pharmacologie , Survie cellulaire/effets des médicaments et des substances chimiques , Protéines recombinantes/pharmacologie , Lignée cellulaire tumorale , Antinéoplasiques alcoylants/pharmacologie , Noyau de la cellule/métabolisme , Noyau de la cellule/effets des médicaments et des substances chimiquesRÉSUMÉ
BACKGROUND/AIM: Colorectal cancer (CRC) is the third-leading cause of death in the world. Although the prognosis has improved due to improvement of chemotherapy, metastatic CRC is still a recalcitrant disease, with a 5-year survival of only 13%. Irinotecan (IRN) is used as first-line chemotherapy for patients with unresectable CRC. However, there are severe side effects, such as neutropenia and diarrhea, which are dose-limiting. We have previously shown that methionine restriction (MR), effected by recombinant methioninase (rMETase), lowered the effective dose of IRN of colon-cancer cells in vitro. The aim of the present study was to evaluate the efficacy of the combination of low-dose IRN and MR on colon-cancer in nude mice. MATERIALS AND METHODS: HCT-116 colon-cancer cells were cultured and subcutaneously injected into the flank of nude mice. After the tumor size reached approximately 100 mm3, 18 mice were randomized into three groups; Group 1: untreated control on a normal diet; Group 2: high-dose IRN on a normal diet (2 mg/kg, i.p.); Group 3: low-dose IRN (1 mg/kg i.p.) on MR effected by a methionine-depleted diet. RESULTS: There was no significant difference between the control mice and the mice treated with high-dose IRN, without MR. However, low-dose IRN combined with MR was significantly more effective than the control and arrested colon-cancer growth (p=0.03). Body weight loss was reversible in the mice treated by low-dose IRN combined with MR. CONCLUSION: The combination of low-dose IRN and MR acted synergistically in arresting HCT-116 colon-cancer grown in nude mice. The present study indicates the MR has the potential to reduce the effective dose of IRN in the clinic.
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Carbon-sulfur lyases , Tumeurs du côlon , Irinotécan , Méthionine , Souris nude , Tests d'activité antitumorale sur modèle de xénogreffe , Animaux , Irinotécan/administration et posologie , Irinotécan/pharmacologie , Méthionine/administration et posologie , Humains , Souris , Tumeurs du côlon/traitement médicamenteux , Tumeurs du côlon/anatomopathologie , Camptothécine/analogues et dérivés , Camptothécine/pharmacologie , Camptothécine/administration et posologie , Camptothécine/usage thérapeutique , Modèles animaux de maladie humaine , Cellules HCT116 , Lignée cellulaire tumorale , Charge tumorale/effets des médicaments et des substances chimiquesRÉSUMÉ
BACKGROUND/AIM: Gliomas are the most common and recalcitrant malignant primary brain tumors. All cancer types are addicted to methionine, which is a fundamental and general hallmark of cancer known as the Hoffman effect. Particularly glioma cells exhibit methionine addiction. Because of methionine addiction, [11C]-methionine positron emission tomography (MET-PET) is widely used for glioma imaging in clinical practice, which can monitor the extent of methionine addiction. Methionine restriction including recombinant methioninase (rMETase) and a low-methionine diet, has shown high efficacy in preclinical models of gliomas, especially in combination with chemotherapy. The aim of the present study was to determine the efficacy of methionine restriction with oral rMETase (o-rMETase) and a low-methionine diet, combined with radiation and temozolomide (TMZ), on a teenage female patient with high-grade glioma. CASE REPORT: A 16-year-old girl was diagnosed with high-grade glioma. Magnetic resonance imaging (MRI) showed a left temporal-lobe tumor with compression to the left lateral ventricle and narrowing of sulci in the left temporal lobe. After the start of methionine restriction with o-rMETase and a low-methionine diet, along with TMZ combined with radiotherapy, the tumor size shrunk at least 60%, with improvement in the left lateral ventricle and sulci. The patient's condition remains stable for 19 months without severe adverse effects. CONCLUSION: Methionine restriction consisting of o-rMETase and a low-methionine diet, in combination with radiation and TMZ as first-line chemotherapy, were highly effective in a patient with high-grade glioma.
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Carbon-sulfur lyases , Gliome , Méthionine , Témozolomide , Humains , Femelle , Gliome/anatomopathologie , Gliome/traitement médicamenteux , Gliome/thérapie , Témozolomide/administration et posologie , Témozolomide/usage thérapeutique , Méthionine/administration et posologie , Adolescent , Imagerie par résonance magnétique , Tumeurs du cerveau/anatomopathologie , Tumeurs du cerveau/traitement médicamenteux , Tumeurs du cerveau/thérapie , Résultat thérapeutique , Grading des tumeurs , Tomographie par émission de positons , Protéines recombinantes/administration et posologie , Association thérapeutiqueRÉSUMÉ
BACKGROUND/AIM: Breast cancer is the most common and the deadliest cancer among women in the world. Treatment options for HER2-positive metastatic breast cancer patients are limited. Trastuzumab deruxtecan (T-DXd), an antibody-drug conjugate (ADC), has recently been introduced as second-line chemotherapy for HER2-positive metastatic breast cancer. The aim of the present study was to evaluate the efficacy of methionine restriction with oral recombinant methioninase (o-rMETase) and a low-methionine diet combined with T-DXd, on a patient with HER2-positive recurrent stage IV breast cancer. CASE REPORT: A 66-year-old female was diagnosed with HER2-positive metastatic breast cancer. Computed tomography (CT) indicated peritoneal dissemination, thickening of the sigmoid colon and splenic flexure and widespread bone metastases. The patient was previously treated with fulvestrant, trastuzumab, pertuzumab, paclitaxel and capecitabine which were ineffective. T-DXd was administered as a second-line chemotherapy. Since the patient experienced strong side effects, the dose of T-Dxd was decreased. The patient began methionine restriction using o-rMETase and a low-methionine diet along with T-DXd. After the start of the combined treatment, CA15-3 and CA27.29, tumor markers for breast cancer, decreased rapidly from a very high level. The levels of both tumor markers are currently normal. Additionally, peritoneal-dissemination nodules, ascites and the thickness of the sigmoid colon and splenic flexure are no longer detected on CT. The patient maintains a high performance status, without severe side effects of the combination treatment. CONCLUSION: Methionine restriction consisting of o-rMETase and a low-methionine diet, in combination with T-DXd as second-line chemotherapy, was highly effective in a patient with HER2-positive stage IV breast cancer.
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Tumeurs du sein , Camptothécine/analogues et dérivés , Carbon-sulfur lyases , Immunoconjugués , Humains , Femelle , Sujet âgé , Tumeurs du sein/traitement médicamenteux , Marqueurs biologiques tumoraux , Trastuzumab/usage thérapeutique , Méthionine , Racéméthionine , Régime alimentaire , Récepteur ErbB-2RÉSUMÉ
BACKGROUND/AIM: Rapamycin and recombinant methioninase (rMETase) have both shown efficacy to target cancer cells. Rapamycin prevents cancer-cell growth by inhibition of the mTOR protein kinase. rMETase, by degrading methionine, targets the methionine addiction of cancer and has been shown to improve the efficacy of chemotherapy drugs. In the present study, we aimed to determine if a synergy exists between rapamycin and rMETase when used in combination against a colorectal-carcinoma cell line, compared to normal fibroblasts, in vitro. MATERIALS AND METHODS: The half-maximal inhibitory concentrations (IC50) of rapamycin alone and rMETase alone against the HCT-116 human colorectal-cancer cell line and Hs-27 human fibroblasts were determined using the CCK-8 Cell Viability Assay. After calculating the IC50 of each drug, we determined the efficacy of rapamycin and rMETase combined on both HCT-116 and Hs-27. RESULTS: Hs-27 normal fibroblasts were more sensitive to rapamycin than HCT-116 colon-cancer cells (IC50=0.37 nM and IC50=1.38 nM, respectively). HCT-116 cells were more sensitive to rMETase than Hs-27 cells (IC50 0.39 U/ml and IC50 0.96 U/ml, respectively). The treatment of Hs-27 cells with the combination of rapamycin (IC50=0.37 nM) and rMETase (IC50=0.96 U/ml) showed no significant difference in their effect on Hs-27 cell viability compared to the two drugs being used separately. However, the treatment of HCT-116 cells with the combination of rapamycin (IC50=1.38 nM) and rMETase (IC50=0.39 U/ml) was able to decrease cancer-cell viability significantly more than either single-drug treatment. CONCLUSION: Rapamycin and rMETase, when used in combination against colorectal-cancer cells, but not normal fibroblasts, in vitro, have a cancer-specific synergistic effect, suggesting that the combination of these drugs can be used as an effective, targeted cancer therapy.
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Tumeurs du côlon , Tumeurs colorectales , Humains , Sirolimus/pharmacologie , Carbon-sulfur lyases , Tumeurs du côlon/traitement médicamenteux , Méthionine , Cellules HCT116 , Protéines recombinantesRÉSUMÉ
BACKGROUND/AIM: The aim of the present study was to determine the synergy of recombinant methioninase (rMETase) and the anti-tubulin agent eribulin on fibrosarcoma cells, in comparison to normal fibroblasts, in vitro. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells and HS27 human fibroblasts were used for in vitro experiments. Four groups were analyzed in vitro: No-treatment control; eribulin; rMETase; eribulin plus rMETase. Dual-color HT1080 cells which express red fluorescent protein (RFP) in the cytoplasm and green fluorescent protein (GFP) in the nuclei were used to visualize cytoplasmic and nuclear dynamics during treatment. RESULTS: Eribulin combined with rMETase greatly decreased the viability of HT 1080 cells. In contrast, eribulin combined with rMETase did not show synergy on Hs27 normal fibroblasts. Eribulin combined with rMETase also caused more fragmentation of the nucleus than all other treatments. CONCLUSION: The combination treatment of eribulin plus rMETase demonstrated efficacy on fibrosarcoma cells in vitro. In contrast, normal fibroblasts were resistant to this combination, indicating the potential clinical applicability of the treatment.
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Carbon-sulfur lyases , Fibrosarcome , Furanes , Cétones , , Humains , Carbon-sulfur lyases/usage thérapeutique , Lignée cellulaire tumorale , Fibrosarcome/traitement médicamenteux , Fibroblastes , Protéines recombinantes/pharmacologie , Protéines recombinantes/usage thérapeutiqueRÉSUMÉ
BACKGROUND/AIM: Irinotecan (IRN), a topoisomerase I inhibitor and pro-drug of SN-38, is first-line treatment of colon cancer as part of FOLFIRI and FOLFOXIRI combination chemotherapy. However, IRN causes dose-limiting adverse events such as neutropenia and diarrhea. Dose reductions are sometimes required, which reduce efficacy. Recombinant methioninase (rMETase) targets the fundamental basis of cancer, methionine addiction, known as the Hoffman effect, and enhances the efficacy of numerous chemotherapy drugs. The present study determined the efficacy of rMETase when administered in combination with IRN. MATERIALS AND METHODS: Cell viability was assessed by cultivating the HCT-116 human colorectal cancer cell line in 96-well plates at 1×103 cells per well in Dulbecco's modified Eagle's medium (DMEM). Subsequently, HCT-116 cells were treated with increasing concentrations of SN-38, the active form of IRN, ranging from 0.5 nM to 32 nM, and/or rMETase ranging from 0.125 to 8 U/ml. After treatment for 72 h, the half-maximal inhibitory concentration (IC50) of SN-38 alone and rMETase alone for HCT-116 cells were determined. Using the IC50 concentration of rMETase, we determined the IC50 of SN-38 in combination with rMETase. Cell viability was determined with the cell-counting Kit-8 with the WST-8 reagent.. RESULTS: The IC50 of rMETase alone for the HCT-116 cells was 0.55 U/ml, and the IC50 of IRN (SN-38) alone was 3.50 nM. rMETase at 0.55 U/ml lowered the IC50 of SN-38 to 0.232 nM (p<0.0001), a 15-fold reduction. CONCLUSION: rMETase and IRN are strongly synergistic, giving rise to the possibility of lowering the effective dose of IRN for the treatment of patients with colon cancer, thereby reducing its severe toxicity. This new strategy will allow more patients with cancer to be effectively treated with IRN.
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Tumeurs du côlon , Humains , Irinotécan/pharmacologie , Tumeurs du côlon/traitement médicamenteux , Carbon-sulfur lyases , Cellules cancéreuses en culture , Protéines recombinantesRÉSUMÉ
BACKGROUND/AIM: Methionine addiction is a fundamental and universal hallmark of cancer, termed the Hoffman effect. Methionine addiction of cancer is greater than glucose addiction, termed the Warburg effect, as shown by the comparison of PET imaging with [11C]methionine and [18F]fluorodeoxyglucose. The aim of the present study was to determine whether [11C]methionine PET (MET-PET) images could be a biomarker of methionine addiction of cancer and potential response to methionine-restriction-based combination chemotherapy. PATIENTS AND METHODS: In the present study a patient with invasive lobular carcinoma of the breast metastatic to axillary lymph nodes was imaged by both MET-PET and [18F]fluorodeoxyglucose PET (FDG-PET) before and after combination treatment with methionine restriction, comprising a low-methionine diet and methioninase, along with first-line chemotherapy. RESULTS: MET-PET gave a much stronger and precise image of the patient's metastatic axillary lymph nodes than FDG-PET. The patient had a complete response to methionine restriction-based chemotherapy as shown by MET-PET. CONCLUSION: MET-PET imaging is a biomarker of methionine-addicted cancer and potential response to methionine-restriction-based chemotherapy.
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Tumeurs du sein , Méthionine , Humains , Femelle , Fluorodésoxyglucose F18 , Marqueurs biologiques tumoraux , Tomographie par émission de positons/méthodes , Racéméthionine , Tumeurs du sein/anatomopathologie , Association de médicaments , RadiopharmaceutiquesRÉSUMÉ
Background/Aim: Regorafenib is a multi-kinase inhibitor, targeting vascular endothelial growth factor receptor 2, fibroblast growth factor receptor 1 and other oncogenic kinases. Regorafenib has efficacy in metastatic colon cancer, but has severe dose-limiting toxicities which cause patients to stop taking the drug. The aim of the present study was to determine if recombinant methioninase (rMETase) could lower the effective concentration of regorafenib in vitro against a colorectal-cancer cell line. Materials and Methods: Firstly, we examined the half-maximal inhibitory concentration (IC50) of regorafenib alone and rMETase alone for the HCT-116 human colorectal-cancer cell line. After that, using the IC50 concentration of each drug, we investigated the efficacy of the combination of regorafenib and rMETase. Results: While both methioninase alone (IC50=0.61 U/ml) and regorafenib alone (IC50=2.26 U/ml) inhibited the viability of HCT-116 cells, the combination of the two agents was more than twice as effective as either alone. Addition of rMETase at 0.61 U/ml lowered the IC50 of regorafenib from 2.26 µM to 1.46 µM. Conclusion: rMETase and regorafenib are synergistic, giving rise to the possibility of lowering the effective dose of regorafenib in patients, thereby reducing its severe toxicity, allowing more cancer patients to be treated with regorafenib.
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Background/Aim: Methionine restriction by diet and recombinant methioninase (rMETase) are effective for cancer therapy by themselves or combined with chemotherapy drugs. We previously showed that oral administration of rMETase-producing Escherichia coli JM109 (E. coli JM109-rMETase) can be installed in the mouse microbiome and inhibit colon-cancer growth in a syngeneic mouse model. In the present report, we investigated the efficacy of oral administration of E. coli JM109-rMETase in an orthotopic triple-negative breast cancer (TNBC) cell-line mouse model. Materials and Methods: First, we established orthotopic 4T1 mouse triple-negative breast cancer on an abdominal mammary gland in female athymic nu/nu nude mice aged 4-6 weeks. After tumor growth, 15 mice were divided into three groups of 5. Group 1 was administered phosphate-buffered saline (PBS) orally by gavage twice daily as a control; Group 2 was administered non-recombinant E. coli JM109 competent cells orally by gavage twice daily as a control; Group 3 was administered E. coli JM109-rMETase cells by gavage twice daily for two weeks. Tumor size was measured with calipers twice per week. On day 15, blood methionine level was examined using an HPLC method. Results: Oral administration of E. coli JM109-rMETase inhibited 4T1 TNBC growth significantly compared to the PBS and E. coli JM109 control groups. On day 15, the blood methionine level was significantly lower in the mice administered E. coli JM109-rMETase than in the PBS control. Conclusion: E. coli JM109-rMETase lowered blood methionine levels and inhibited TNBC growth in an orthotopic cell-line mouse model, suggesting future clinical potential against a highly recalcitrant cancer.
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BACKGROUND/AIM: The fundamental and general hallmark of cancer cells, methionine addiction, termed the Hoffman effect, is due to overuse of methionine for highly-increased transmethylation reactions. In the present study, we tested if the combination efficacy of recombinant methioninase (rMETase) and a methionine analogue, ethionine, could eradicate osteosarcoma cells and down-regulate the expression of c-MYC. MATERIALS AND METHODS: 143B osteosarcoma cells and Hs27 normal human fibroblasts were tested. The efficacy of rMETase alone and ethionine, alone and in their combination, on cell viability was determined with the WST-8 assay on 143B cells and Hs27 cells. c-MYC expression was examined with western immunoblotting and compared in 143B cells treated with/without rMETase, ethionine, or the combination of both rMETase and ethionine. RESULTS: 143B cells were more sensitive to both rMETase and ethionine than Hs 27 cells, with the following IC50s: rMETase (143B: 0.22 U/ml; Hs27: 0.82 U/ml); ethionine (143B: 0.24 mg/ml; Hs27: 0.42 mg/ml). The combination of rMETase and ethionine synergistically eradicated 143B cells, lowering the IC50 for ethionine 14-fold compared to ethionine alone (p<0.001). In contrast, Hs27 fibroblasts were relatively resistant to the combination. The expression of c-MYC was significantly down-regulated only by the combination of rMETase and ethionine in 143B cells (p<0.001). CONCLUSION: In the present study, we showed, for the first time, the synergistic combination efficacy of rMETase and ethionine on osteosarcoma cells in contrast to normal fibroblasts, which were relatively resistant. The combination of rMETase and ethionine down-regulated c-MYC expression in the cancer cells. The present results indicate the combination of rMETase and ethionine may reduce the malignancy of osteosarcoma cells and can be a potential future clinical strategy.
Sujet(s)
Tumeurs osseuses , Ostéosarcome , Humains , Tumeurs osseuses/traitement médicamenteux , Éthionine/usage thérapeutique , Méthionine/métabolisme , Ostéosarcome/traitement médicamenteux , Ostéosarcome/anatomopathologie , Racéméthionine , Protéines recombinantes/usage thérapeutiqueRÉSUMÉ
All types of cancer cells are addicted to methionine, which is known as the Hoffman effect. Restricting methionine inhibits the growth and proliferation of all tested types of cancer cells, leaving normal cells unaffected. Targeting methionine addiction with methioninase (METase), either alone or in combination with common cancer chemotherapy drugs, has been shown as an effective and safe therapy in various types of cancer cells and animal cancer models. About six years ago, recombinant METase (rMETase) was found to be able to be taken orally as a supplement, resulting in anecdotal positive results in patients with advanced cancer. Currently, there are 8 published clinical studies on METase, including two from the 1990s and six more recent ones. This review focuses on the results of clinical studies on METase-mediated methionine restriction, in particular, on the dosage of oral rMETase taken alone as a supplement or in combination with common chemotherapeutic agents in patients with advanced cancer.
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BACKGROUND/AIM: Methionine addiction is the elevated requirement for exogenous methionine for growth and survival of cancer cells, termed the Hoffman effect. Methionine-addicted cancer cells synthesize normal or excess amounts of methionine but still need an external source of methionine. Methionine restriction (MR) by either a methionine-free medium or in vivo by a low-methionine diet or by methioninase, selectively arrests cancer cells in the late S/G2 cell cycle phase, but not normal cells. The present study focuses on the comparison of production and secretion of exosomes by cancer cells under MR and normal conditions. MATERIALS AND METHODS: MDA-MB-231 cells (triple-negative breast cancer), containing exosomes labeled with CD63-GFP (CD63-GFP exosomes), were visualized by fluorescence microscopy. MDA-MB-231 cells expressing exosome-specific CD63-GFP were cultured in methionine-containing (MET+) or in methionine-free (MET-) DMEM conditions. Exosomes were isolated from conditioned medium of cultured MDA-MD-231 cells by ultracentrifugation and characterized by nanoparticle tracking analysis (NTA) and Western blotting. RESULTS: When MDA-MB-231-CD63-GFP cells were cultured under MR conditions, they arrested their growth and CD63-GFP-expressing exosomes were strongly increased in the cells. MR resulted in approximately a 2-fold increase in exosome production and secretion per cell, even though cell growth was arrested. Methionine restriction thus resulted in elevated exosome production and secretion per surviving cell. CONCLUSION: Exosome production and secretion in the cancer cells increased under MR, suggesting a relation between MR and exosome production and secretion.
Sujet(s)
Tumeurs du sein , Exosomes , Humains , Femelle , Méthionine/métabolisme , Exosomes/métabolisme , Tumeurs du sein/métabolisme , Prolifération cellulaire , Racéméthionine/métabolismeRÉSUMÉ
BACKGROUND/AIM: The choice of chemotherapy agents for RAS-mutant colorectal cancer is limited, and prognosis is poor compared to RAS-wild-type colorectal cancer. The purpose of the present study was to evaluate the effectiveness of methionine restriction combined with chemotherapy in a patient with NRAS-mutant rectal cancer. PATIENTS AND METHODS: A 59-year-old female was diagnosed with lung-metastatic recurrence of NRAS-mutant rectal cancer two and a half years after resection of the primary tumor. She started chemotherapy, which consisted of fluorouracil, irinotecan (FOLFIRI), and bevacizumab, in October 2020. Eight months later, stereotactic body radiation therapy (SBRT) was performed to treat the lung metastases. She stopped chemotherapy at this point and had blood tests and computed tomography (CT) scans regularly. Her CEA level increased to 139.91 ng/ml and her lung metastasis became larger by September 2022. Therefore, she was reintroduced to FOLFIRI and bevacizumab in October 2022, and also started a low-methionine diet and oral recombinant methioninase (o-rMETase) as a supplement. RESULTS: After starting the combination therapy with o-rMETase, a low-methionine diet, FOLFIRI, and bevacizumab, blood CEA levels very rapidly decreased and were almost within the normal limits five months later. CT findings showed the lung metastasis did not grow. CONCLUSION: Methionine restriction comprising o-rMETase and a low-methionine diet combined with first-line chemotherapy was effective in a patient with NRAS-mutant rectal cancer in which metastasis had re-occurred after first-line chemotherapy alone.
Sujet(s)
Tumeurs colorectales , Tumeurs du poumon , Tumeurs du rectum , Humains , Femelle , Adulte d'âge moyen , Bévacizumab , Tumeurs colorectales/anatomopathologie , Camptothécine/usage thérapeutique , Camptothécine/effets indésirables , Tumeurs du rectum/traitement médicamenteux , Tumeurs du rectum/génétique , Fluorouracil , Tumeurs du poumon/traitement médicamenteux , Tumeurs du poumon/génétique , Méthionine , Régime alimentaire , Protocoles de polychimiothérapie antinéoplasique/effets indésirables , Métastase tumorale/traitement médicamenteux , Protéines membranaires , dGTPases/génétiqueRÉSUMÉ
BACKGROUND: Colorectal cancer liver metastasis (CCLM) is the most frequent cause of death of colorectal cancer. Development of novel new effective therapy is needed for CCLM patients to improve outcome. The aim of the present study was to investigate the efficacy of recombinant methioninase (rMETase) on a CCLM orthotopic mouse model of liver metastasis established using the human colon cancer cell line HT29 expressing red fluorescent protein (RFP). MATERIALS AND METHODS: Orthotopic CCLM nude mouse models were randomized into two groups: control group (n = 6, PBS 200 µl, i.p., daily); rMETase group (n = 6, 100 units/200 µl, i.p., daily). Tumor volume was measured on day 0 and day 15. Body weight was measured twice a week. All mice were sacrificed on day 15. RESULTS: rMETase significantly inhibited the increase of the liver metastasis as determined by RFP fluorescence area and intensity (p = 0.016 and 0.015, respectively). There was no significant difference of body weight between either group on any day. CONCLUSIONS: The present study suggests that rMETase has future potential therapy for CCLM in the clinic.
Sujet(s)
Tumeurs du côlon , Tumeurs du foie , Humains , Souris , Animaux , Tumeurs du côlon/traitement médicamenteux , Tumeurs du côlon/anatomopathologie , Poids , Tumeurs du foie/traitement médicamenteuxRÉSUMÉ
BACKGROUND/AIM: Methionine addiction is a general and fundamental hallmark of cancer cells, termed the Hoffman effect. Previously Vanhamme and Szpirer showed that methionine addiction could be induced by transfection of the activated HRAS1 gene to a normal cell line. In the present study, we investigated the role of the c-MYC oncogene in methionine addiction of cancer, by comparison of c-Myc expression and malignancy of methionine-addicted osteosarcoma cells and rare methionine-independent revertants, derived from the methionine-addicted cells. MATERIALS AND METHODS: Methionine-independent revertant 143B osteosarcoma cells (143B-R) were derived from methionine-addicted parental 143B osteosarcoma cells (143B-P), by continuous culture in medium depleted of methionine by recombinant methioninase. To compare in vitro malignancy of methionine-addicted parental cells and methionine-independent revertant cells, the following experiments were performed: for 143B-P and 143B-R cells, cell proliferation capacity was measured with a cell-counting assay, and colony-formation capacity was determined on plastic and in soft agar, all in methionine-containing Dulbecco's Modified Eagle's Medium (DMEM). Tumor growth was measured in orthotopic xenograft nude-mouse models, to compare in vivo malignancy of 143B-P and 143B-R cells. c-MYC expression was examined with western immunoblotting and compared in 143B-P and 143B-R cells. RESULTS: 143B-R cells had reduced cell proliferation capacity, compared to 143B-P cells, in methionine-containing medium (p=0.003). 143B-R cells had reduced colony formation capacity on plastic (p=0.003) and in soft agar, compared to 143B-P cells in methionine-containing medium. 143B-R cells had reduced tumor growth in orthotopic xenograft nude-mouse models, compared to 143B-P cells, (p=0.002). These results demonstrate that 143B-R methionine-independent revertant cells lost malignancy. Expression of c-MYC was reduced in 143B-R methionine-independent revertant osteosarcoma cells, compared to 143B-P cells, (p=0.0007). CONCLUSION: The present study demonstrated that c-MYC expression is linked to malignancy and methionine addiction of cancer cells. The present study on c-MYC, and the previous study on HRAS1, suggest that oncogenes may play a role in methionine addiction, which is a hallmark of all cancers, as well as in malignancy.