Morinaga Sei, Han Qinghong, Mizuta Kohei, Kang Byung Mo, Bouvet Michael, Yamamoto Norio, Hayashi Katsuhiro, Kimura Hiroaki, Miwa Shinji, Igarashi Kentaro, Higuchi Takashi, Tsuchiya Hiroyuki, Demura Satoru, Hoffman Robert M
AntiCancer Inc., San Diego, CA, U.S.A.
Department of Surgery, University of California, San Diego, CA, U.S.A.
Anticancer Res. 2024 Dec;44(12):5207-5213. doi: 10.21873/anticanres.17347.
BACKGROUND/AIM: Docetaxel combined with gemcitabine is a second-line treatment for soft-tissue sarcoma; however, its effectiveness is limited because of docetaxel resistance. The objective of the present study was to determine the potential of recombinant methioninase (rMETase) to enhance the efficacy of docetaxel on high-docetaxel-resistant human fibrosarcoma cells in vitro.
Docetaxel-resistant HT1080 (DTR-HT1080) human fibrosarcoma cells were established by culturing them in by progressively increasing concentrations of docetaxel from 0.02 to 9 nM in vitro. The IC values for docetaxel and rMETase, as well as the efficacy of their combination, in inhibiting HT1080 human fibrosarcoma cells, DTR-HT1080 cells, and Hs27 normal human fibroblasts were determined. Four experimental groups were examined in vitro: control group without treatment; docetaxel alone; rMETase alone; docetaxel combined with rMETase.
The IC of docetaxel for DTR-HT1080 cells was 7.57 nM, compared to the parental HT1080 cells with an IC of 1.68 nM, a 4.5-fold increase. The IC of docetaxel on Hs27 fibroblasts was 4.46 nM. The IC of rMETase on HT1080 cells was 0.75 U/ml (data from [6]). The IC of rMETase on DTR-HT1080 cells was 0.55 U/ml. The IC of rMETase on Hs27 fibroblasts was 0.93 U/ml (data from [6]). Docetaxel (1.68 nM [IC]) plus rMETase (0.75 U/ml [IC]) synergistically reduced the viability of HT1080 cells (p<0.05). In contrast, docetaxel (4.46 nM) plus rMETase (0.93 U/ml) did not reduce the viability of Hs27 fibroblasts, compared to either agent alone. The combination of rMETase (0.55 U/ml [IC]) and docetaxel (1.68 nM [IC of the parental cells]) overcame docetaxel resistance of DTR-HT1080 cells, resulting in an inhibition of 48.1% compared to docetaxel alone (6.8%) or rMETase alone (37.5%) (p<0.05). rMETase thus increased the efficacy of docetaxel 7-fold on docetaxel-resistant human fibrosarcoma cells.
The combination of docetaxel and rMETase was synergistic on HT1080 fibrosarcoma cells, but not normal fibroblasts. rMETase plus docetaxel synergistically reduced the high docetaxel resistance of DTR-HT1080 cells. The present results indicate the clinical potential of rMETase to reduce docetaxel resistance in soft-tissue sarcoma patients in the future.
背景/目的：多西他赛联合吉西他滨是软组织肉瘤的二线治疗方案；然而，由于多西他赛耐药，其疗效有限。本研究的目的是确定重组甲硫氨酸酶（rMETase）在体外增强多西他赛对高多西他赛耐药人纤维肉瘤细胞疗效的潜力。
通过在体外将多西他赛浓度从0.02 nM逐步增加至9 nM培养，建立多西他赛耐药的HT1080（DTR-HT1080）人纤维肉瘤细胞。测定多西他赛和rMETase对HT1080人纤维肉瘤细胞、DTR-HT1080细胞和Hs27正常人成纤维细胞的半数抑制浓度（IC值）及其联合用药的疗效。体外检测四个实验组：未治疗的对照组；单独使用多西他赛；单独使用rMETase；多西他赛联合rMETase。
多西他赛对DTR-HT1080细胞的IC值为7.57 nM，而亲本HT1080细胞的IC值为1.68 nM，增加了4.5倍。多西他赛对Hs27成纤维细胞的IC值为4.46 nM。rMETase对HT1080细胞的IC值为0.75 U/ml（数据来自[6]）。rMETase对DTR-HT1080细胞的IC值为0.55 U/ml。rMETase对Hs2成纤维细胞的IC值为0.93 U/ml（数据来自[6]）。多西他赛（1.68 nM[IC值]）加rMETase（0.75 U/ml[IC值]）协同降低了HT1080细胞的活力（p<0.05）。相比之下，多西他赛（4.46 nM）加rMETase（0.93 U/ml）与单独使用任何一种药物相比，均未降低Hs27成纤维细胞的活力。rMETase（0.55 U/ml[IC值]）与多西他赛（1.68 nM[亲本细胞的IC值]）联合用药克服了DTR-HT1080细胞的多西他赛耐药性，与单独使用多西他赛（6.8%）或单独使用rMETase（37.5%）相比，抑制率达到48.1%（p<0.05）。因此，rMETase使多西他赛对多西他赛耐药人纤维肉瘤细胞的疗效提高了7倍。
多西他赛与rMETase联合用药对HT1080纤维肉瘤细胞具有协同作用，但对正常成纤维细胞无此作用。rMETase加多西他赛可协同降低DTR-HT1080细胞的高多西他赛耐药性。目前的结果表明rMETase未来在降低软组织肉瘤患者多西他赛耐药性方面具有临床潜力。
