Antagonism of chemotherapy-induced cytotoxicity for human breast cancer cells by antiestrogens

In a prior National Surgical Adjuvant Breast and Bowel Project (NSABP) adjuvant study, the addition of the antiestrogen tamoxifen to chemotherapy with melphalan and fluorouracil adversely affected survival in several patient subsets, suggesting an antagonistic drug interaction. To investigate this possibility, we studied the interaction of tamoxifen and other antiestrogens with several cytotoxic drugs in cultured human breast cancer cell lines. Clinically relevant concentrations of tamoxifen and melphalan reduced colony survival of estrogen receptor (ER)-positive breast cancer cells when used alone in a colony-forming assay. However, pretreatment of cells with tamoxifen followed by exposure to melphalan resulted in antagonism, with more colonies surviving treatment with the combination than with melphalan alone. Identical effects were seen using several other triphenylethelene antiestrogens. An antagonistic interaction was observed even with a brief preincubation with tamoxifen that had no effect on cell proliferation, indicating that antagonism was not due to tamoxifen's known cell kinetic effects. Tamoxifen even antagonized melphalan cytotoxicity in ER-negative breast cancer cells and in cultured liver cells. An additive drug interaction occurred when melphalan was combined with pharmacologic concentrations of estradiol or medroxyprogesterone acetate, but antagonism was also observed with dexamethasone. Tamoxifen also antagonized the cytotoxicity of fluorouracil in these cells. However, an additive interaction occurred when the antiestrogen was combined with doxorubicin or 4-hydroxy-cyclophosphamide, an alkylating agent that is transported into the cell by a different carrier-mediated mechanism than melphalan. To avoid potential antagonism in the clinic, combinations of tamoxifen with melphalan and/or fluorouracil should be avoided.     

Nanomicellar paclitaxel increases cytotoxicity of multidrug resistant breast cancer cells

Multidrug resistance (MDR) of breast cancer cells still represents an unmet medical need in chemotherapy. To this end, the purpose of this study was to determine efficacy of paclitaxel loaded in sterically stabilized, biocompatible and biodegradable sterically stabilized mixed phospholipid nanomicelles (SSMM; size, ∼15 nm) and actively targeted vasoactive intestinal peptide-grafted SSMM (SSMM-VIP) in circumventing P-gp-mediated paclitaxel resistance in BC19/3 cells, a human breast cancer cell line that expresses >10-fold higher P-gp than its parental sensitive cell line, MCF-7. We found that in drug sensitive MCF-7 cells, paclitaxel loaded in SSMM (P-SSMM) and SSMM-VIP (P-SSMM-VIP) significantly inhibited cell growth in dose-dependent fashion (p < 0.05). Both formulations were ∼7-fold more potent than paclitaxel dissolved in DMSO (P-DMSO). Efficacy of P-SSMM and P-SSMM-VIP was similar (p > 0.5). By contrast, in drug resistant BC19/3 cells, P-SSMM-VIP was significantly more effective than either P-SSMM or P-DMSO (∼2- and 5-fold, respectively; p < 0.05). Collectively, these data indicate that actively targeted paclitaxel-loaded SSMM-VIP overcomes multiple drug resistance of BC19/3 cells. We suggest this formulation should be further developed to treat MDR breast cancer.     

Antagonism of buthionine sulfoximine cytotoxicity for human neuroblastoma cell lines by hypoxia is reversed by the bioreductive agent tirapazamine

Relapse of neuroblastoma (NB) commonly occurs in hypoxic tissues. Buthionine sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, is cytotoxic for NB cell lines in atmospheric oxygen (20% O(2)). Tirapazamine (TPZ) is a bioreductive agent that forms a toxic-free radical in hypoxia. We determined in four NB cell lines cytotoxicity using the DIMSCAN digital imaging fluorescence assay, glutathione (GSH) levels by the DTNB-GSSG reductase method, apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (Delta psi(m)) by flow cytometry. Hypoxia (2% O(2)) antagonized BSO-mediated ROS, apoptosis, and cytotoxicity but not GSH depletion. TPZ synergistically enhanced BSO cytotoxicity in hypoxia for all four NB cell lines, achieving 2-4 logs of cell kill. BSO depleted GSH (8-42% of controls) in 20 and 2% O(2), whereas TPZ only decreased GSH in hypoxia. Maximal GSH depletion was induced by BSO + TPZ. N-acetylcysteine abrogated GSH depletion caused by TPZ but not by BSO. BSO increased ROS, decreased Delta psi(m), and caused apoptosis in 20% O(2) (but not in 2% O(2)). TPZ elevated ROS in 2% O(2) (but not in 20% O(2)), whereas BSO + TPZ increased ROS both in 20 and 2% O(2). In hypoxia, TPZ alone or TPZ + BSO caused an 80% decrease of Delta psi(m) at 24 h, preceding apoptosis in 74-86% of cells at 48 h. Thus, hypoxia significantly antagonizes BSO-mediated cytotoxicity for NB cell lines, but TPZ reversed the inhibition of BSO-mediated cytotoxicity in hypoxia, causing increased ROS, Delta psi(m) decrease, GSH depletion, apoptosis, and synergistic cytotoxicity. These data additionally define the role of ROS in BSO-mediated cytotoxicity and suggest that combining BSO with TPZ could have clinical activity against NB in hypoxic sites.     

Influence of low pH on cytotoxicity of paclitaxel, mitoxantrone and topotecan.

The extracellular pH (pHe) of solid tumours is often lower than in normal tissues, and this may influence the uptake and/or activity of anti-cancer drugs. The cytotoxicity of mitoxantrone, paclitaxel and topotecan was therefore assessed at low pHe and after manipulation of intracellular pH (pHi) in murine EMT6 and in human MGH-U1 cells. The cytotoxic efficacy of all three agents was reduced at pHe 6.5 as compared with pHe 7.4. The ionophore nigericin and inhibitors of membrane-based ion exchange mechanisms that regulate pHi (5-[N-ethyl-N-isopropyl] amiloride, EIPA; 4,4-diisothiocyanstilbene 2,2-disulphonic acid, DIDS) were used to cause intracellular acidification. Combined use of the cytostatic drugs with pHi modifiers reduced their cytotoxicity under both physiological and low-pHe conditions. The uptake into cells of mitoxantrone (a weak base) was inhibited at pHe 6.5 as compared with pHe 7.4, and smaller effects of low pHe to inhibit uptake of topotecan were also observed. DNA analysis of cell cycle distribution revealed that intracellular acidification, as observed during incubation at low pHe and/or using pHi modifiers, resulted in accumulation of cells in G1 phase, where they may be more resistant to these drugs. Reduced uptake of weak bases (mitoxantrone) at low pHe and altered cell cycle kinetics upon acidification are the postulated causes of reduced cytotoxicity of the agents investigated.     

Rituximab-mediated sensitization of B-non-Hodgkin's lymphoma (NHL) to cytotoxicity induced by paclitaxel,gemcitabine, and vinorelbine

Non-Hodgkin's lymphoma (NHL) responds initially to chemotherapy, however, the disease often relapses and acquires a chemoresistant phenotype. Third line treatment options such as paclitaxel, gemcitabine, and vinorelbine have been tried in patients with refractory or relapsed NHL with antilymphoma activity. Currently, rituximab (anti-CD20) has been approved for treatment of indolent NHL, with significant activity in a wide spectrum of B-cell malignancies, though a percentage of patients do not respond to rituximab treatment. Previous findings from our laboratory have demonstrated that rituximab can sensitize drug-resistant NHL B-lymphoma in vitro to some chemotherapeutic drugs. Hence, in this study, we examined the effect of combination treatment of rituximab and the drugs paclitaxel, gemcitabine, and vinorelbine on various NHL cell lines. Our findings indicate that pretreatment of NHL tumor cells with rituximab sensitizes drug-resistant NHL tumor cells to drug-mediated cytotoxicity. These findings suggest the potential clinical application of combination treatments of rituximab and paclitaxel, gemcitabine or vinorelbine in the treatment of drug/rituximab refractory non-Hodgkin's lymphoma.     

Sequence-dependent cytotoxicity of etoposide and paclitaxel in human breast and lung cancer cell lines

Purpose: To evaluate the effect of schedule on the interaction of etoposide with paclitaxel in vitro against the A549 human lung cancer cell line and the MDA-231 and MCF-7 human breast cancer cell lines. Methods: Exposure schedules that were 24-h concurrent, 24-h sequential, and sequential 24-h with a 24-h intervening drug-free period were quantitatively evaluated by the use of the median-effect principle and the combination index. The clonogenic assay was used to assess cytotoxicity, and calculations were done with computer software. Results: Concurrent exposures were less than additive in two of the three cell lines tested. Sequential 24-hour and sequential 24-h with an intervening 24-h drug-free period showed synergism at high effect levels in all three cell lines. Similar synergistic interactions were found when either agent was administered first. Conclusions: These results show a schedule-dependent cytotoxic interaction between etoposide and paclitaxel in the human lung and breast cancer cell lines evaluated, with optimal synergism occurring with sequential, but not with concurrent, treatment. Received: 19 December 1996 / Accepted: 13 October 1997     

Antagonism of Myc functions by Arf

The Arf-Mdm2-p53 tumor suppressor pathway is activated by sustained hyperproliferative signals emanating from oncoproteins such as Myc. A recent study reveals a novel level of feedback control, whereby induced p19(Arf) binds to Myc and blocks cell proliferation by selectively impairing its transactivation functions.     

Differential regulation of the cytotoxicity activity of paclitaxel by orobol and platelet derived growth factor in human ovarian carcinoma cells

Paclitaxel (PX) binds to and stabilizes tubulin, preventing depolymerization, and resulting in cell death. Based on a previous report showing the activity of phosphatidylinositol kinase (PIK) on tubulin, we investigated the effect of the PI4K inhibitor orobol and the PI3K activator platelet derived growth factor (PDGF) on PX sensitivity. Drug sensitivity was examined by classical colony forming assay. Tubulin isotype expression was determined by semi-quantitative RT-PCR. Microtubule texture was observed by laser confocal microscope using anti-beta-tubulin antibody. Apoptotic activity was estimated by frequency of condensed nuclear chromatin with Hoechst 33342 stain. Orobol enhanced PX sensitivity of human ovarian carcinoma 2008 cells by 18.9+/-1.2-fold (N=3; P<0.01). In contrast, pretreatment with PDGF rendered cells resistant to PX by 2.3+/-0.4-fold (N=3; P<0.01). Neither orobol nor PDGF showed any effect on cell growth. Orobol produced a 2.5-fold sensitization in cisplatin-resistant 2008/C13*5.25 (C13) cells, and PDGF rendered the cells 2.3-fold resistant to PX. Orobol suppressed the beta 4a-tubulin isotype expression by 85% and other isotypes by 20%. In contrast, PDGF induced beta 4a-tubulin isotype expression by 1.3-fold, while it supressed all the other isotypes by 20-40%. Orobol produced thick microtubules and PDGF generated ring condensed microtubules. Orobol promoted PX-induced apoptosis, while PDGF caused 50% reduction of apoptosis. These results indicate that orobol and PDGF regulate PX sensitivity by reciprocally altering the proportion of tubulin isotype expression and PX-induced apoptotic signaling.     

Effects of gamma-linolenic acid and oleic acid on paclitaxel cytotoxicity in human breast cancer cells

It has been suggested that dietary interventions may improve the effectiveness of cancer chemotherapy. We have examined the combined in vitro cytotoxicity of paclitaxel and the fatty acids gamma-linolenic acid (GLA, 18:3n-6) and oleic acid (OA, 18:1n-9) in human breast carcinoma MDA-MB-231 cells. The effect of fatty acids on paclitaxel chemosensitivity was determined by comparing IC(50) and IC(70) (50 and 70% inhibitory concentrations, respectively) obtained when the cells were exposed to IC(50) and IC(70) levels of paclitaxel alone and fatty acids were supplemented either before or during the exposure to paclitaxel. The 3-4,5-dimethylthiazol-2-yl-2,5-diphenyl-tetrazolium bromide (MTT) assay was used to determine cell growth inhibition. GLA by itself showed antiproliferative effects, and a possible GLA-paclitaxel interaction at the cellular level was assessed by the isobologram and the combination-index (CI) methods. Isobole analysis at the isoeffect levels of 50 and 70% revealed that drug interaction was predominantly synergistic when GLA and paclitaxel were added concurrently for 24 h to the cell cultures. Interaction assessment using the median-effect principle and the combination-index (CI) method showed that exposure of MDA-MB-231 cells to an equimolar combination of concurrent GLA plus paclitaxel for 24 h resulted in a moderate synergism at all effect levels, consistent with the results of the isobologram analysis. When exposure to GLA (24 h) was followed sequentially by paclitaxel (24 h) only an additive effect was observed. The GLA-mediated increase in paclitaxel chemosensitivity was only partially abolished by Vitamin E, a lipid peroxidation inhibitor, suggesting a limited influence of the oxidative status of GLA in achieving potentiation of paclitaxel toxicity. When OA (a non-peroxidisable fatty acid) was combined with paclitaxel, an enhancement of chemosensitivity was found when OA was used concurrently with paclitaxel, although less markedly than with GLA. Pretreatment of MDA-MB-231 cells with OA for 24 h prior to a 24 h paclitaxel exposure produced greater enhancement of paclitaxel sensitivity at high OA concentrations than the concurrent exposure to OA and paclitaxel. The OA-induced sensitisation to paclitaxel was not due to the cytoxicity of the fatty acid itself. When these observations were extended to three additional breast carcinoma cell lines (SK-Br3, T47D and MCF-7), simultaneous exposure to GLA and paclitaxel also resulted in synergism. GLA preincubation followed by paclitaxel resulted in additivity for all cell lines. Simultaneous exposure to paclitaxel and OA enhanced paclitaxel cytotoxicity in T47D and MCF-7 cells, but not in SK-Br3 cells, whereas preincubation with OA failed to increase paclitaxel effectiveness in all three cell lines. For comparison, the effects of other fatty acids on paclitaxel chemosensitivity were examined: GLA was the most potent at enhancing paclitaxel cytotoxicity, followed by alpha-linolenic acid (ALA; 18:3n.3), eicosapentaenoic acid (EPA; 20:5n-3) and docosahexaenoic acid (DHA; 22:6n-3), whereas linoleic acid (LA; 18:2n-6) did not increase paclitaxel toxicity. These findings provide experimental support for the use of fatty acids as modulators of tumour cell chemosensitivity in paclitaxel-based therapy.     

Antagonism of Microsporum species by soil fungi

Eighteen fungi isolated from soil by hair bating method were tested against soil inhabiting Microsporum equinum , Microsporum fulvum , Microsporum gypseum and Microsporum racemosum for their antagonistic interactions. Colony inhibition during dual cultures showed inhibition of all the four Microsporum species. The maximum inhibition of M. equinum , M. fulvum , M. gypseum and M. racemosum was caused by Chrysosporium keratinophilum , Chrysosporium tropicum , Curvularia lunata and Chrysosporium lucknowense in dual cultures. On the other hand, M. fulvum showed maximum inhibition of Macrophomina phaseolina (70.1%) while M. equinum , M. gypseum and M. racemosum showed maximum inhibition of Colletotrichum gloeosporoides . Staling products of C. lucknowense accelerated growth of all Microsporum species, C. keratinophilum 3 and C hrysosporium evolceaunui and M. phaseolina accelerated growth of two species of Microsporum . Staling product of Alternaria alternata was most inhibitory. Culture filtrates of Trichophyton vanbreseughemii accelerated the growth of all the four Microsporum species and C. tropicum , C. lucknowense accelerated growth of two species, while Botryotrichum piluliferum accelerated growth of three species of Microsporum . Volatiles showed inhibition of all the Microsporum species ranging from 0.33 to 57.2% except in case of M. fulvum . Lysis of Microsporum mycelium was the most common feature.     

Novel application of multicellular layers culture for in situ evaluation of cytotoxicity and penetration of paclitaxel

Limited drug penetration into tumor tissue is one of the major factors causing clinical drug resistance in human solid tumors. The multicellular layers (MCL) of human cancer cells have been successfully used to study tissue pharmacokinetics of anticancer drugs. The purpose of this study was to develop a direct and simple method to evaluate vitality changes in situ within MCL using calcein-AM. Human colorectal (DLD-1, HT-29) and bladder (HT-1376, J-82) cancer cells were grown in Transwell inserts to form MCL and subjected to paclitaxel exposure. The drug distribution was evaluated using paclitaxel-rhodamine. Photonic attenuation and limited penetration of calcein-AM prevented cellular vitality evaluation on optical sections under confocal microscopy in DLD-1 MCL. However, direct measurement of the fluorescence intensity on frozen sections of MCL allowed successful vitality assessment in more than 80% depth for HT-29 and J-82 MCL and in the upper 40% depth for DLD-1 and HT-1376 MCL. The penetration of paclitaxel-rhodamine was greater in HT-29 than DLD-1 and its distribution pattern was correlated to the spatial profile of vitality deterioration in both MCL, suggesting that tissue penetration may be an important determinant of drug effect in tumors. In conclusion, a novel method for vitality evaluation in situ within MCL was developed using calcein-AM. This method may provide clinically relevant data regarding the spatial pharmacodynamics of anticancer agents within avascular regions of solid tumors. ( Cancer Sci 2008; 99: 423–431)     

Sequence-dependent enhancement of cytotoxicity produced by ecteinascidin 743 (ET-743) with doxorubicin or paclitaxel in soft tissue sarcoma cells.

Ecteinascidin 743 (ET-743) is a potent antitumor agent from the Caribbean tunicate Ecteinascidin turbinata and is presently in clinical trials for human cancers. To better understand how ET-743 might be used clinically, the present study used SRB assays to examine the cytotoxicity resulting from combining ET-743 with three other antineoplastic agents: doxorubicin (DXR), trimetrexate, and paclitaxel in different administration schedules in two soft tissue sarcoma cell lines, HT-1080 and HS-18, in vitro. Concurrent exposure of ET-743 with DXR resulted in synergistic interactions in both cell lines. Addition of ET-743 for 24 h before DXR was the most effective cytotoxic regimen against both cell lines. Morphological study by fluorescence microscopy revealed that combination treatment of both cells with ET-743 and DXR induced apoptosis. Exposure to paclitaxel before ET-743 was also an effective regimen. These results encourage studies of the combination of ET-743 and DXR in the treatment of soft tissue sarcoma, because each of these agents have activity in this disease.     

Prolactin receptor antagonism reduces the clonogenic capacity of breast cancer cells and potentiates doxorubicin and paclitaxel cytotoxicity

Introduction

Exogenous prolactin is mitogenic and antiapoptotic in breast cancer cells, and overexpression of autocrine prolactin cDNA in breast cancer cell lines has been shown to stimulate their growth and to protect against chemotherapy-induced apoptosis. We examined the effects of the 'pure' prolactin receptor antagonist Δ1–9-G129R-hPrl (Δ1–9) on the breast cancer cell number and clonogenicity, alone and in combination with chemotherapy.

Methods

The effects of doxorubicin, paclitaxel and Δ1–9 on the growth of breast cancer cell lines (MCF-7, T47D, MDA-MB-453, MDA-MB-468 and SK-BR-3) in monolayer culture were assessed by the sulphorhodamine B assay. Effects on clonogenicity were assessed by soft agar assay for the cell lines and by the mammosphere assay for disaggregated primary ductal carcinoma in situ samples. Dual-fluorescence immunocytochemistry was used to identify subpopulations of cells expressing the prolactin receptor and autocrine prolactin.

Results

Δ1–9 as a single agent had no effect on the cell number in monolayer culture, but potentiated the cytotoxic effects of doxorubicin and paclitaxel. Doxorubicin accordingly induced expression of prolactin mRNA and protein in all five breast cancer cell lines tested. Δ1–9 alone inhibited the clonogenicity in soft agar of cell lines by ~90% and the mammosphere forming efficiency of six disaggregated primary ductal carcinoma in situ samples by a median of 56% (range 32% to 88%). Subpopulations of cells could be identified in the cell lines based on the prolactin receptor and prolactin expression.

Conclusion

Autocrine prolactin appears to act as an inducible survival factor in a clonogenic subpopulation of breast cancer cells. The rational combination of cytotoxics and Δ1–9 may therefore improve outcomes in breast cancer therapy by targeting this cell population.     

Neoadjuvant weekly paclitaxel followed by FAC

Conclusions The near doubling of the pathologic complete response rate seen for weekly scheduling in this trial motivates further examination of this schedule in early-stage breast cancer.     

组蛋白去乙酰化酶抑制剂协同紫杉醇对人肺癌细胞株抑制作用及机制

背景与目的:组蛋白去乙酰化酶(histone deacetylase,HDAC)抑制剂通过抑制多种基因或蛋白介导的信号转导网络的功能,影响细胞增殖及对化疗药物的敏感性。HDAC抑制剂可能会提高紫杉醇对肺癌细胞的抑制作用。本研究评价HDAC抑制剂曲古抑菌素A(trichostatin A,TSA)协同紫杉醇抑制肺癌细胞H322及H1299的作用及机制。方法:将H322和H1299细胞分别分成4组:(1)对照组;(2)紫杉醇组(TAX);(3)TSA组;(4)以TSA预先作用12h后,再使用紫杉醇的联合用药组(TF)。分别以MTT法、流式细胞术检测细胞增殖情况以及细胞周期、细胞凋亡等指标的变化,荧光显微镜观察细胞核形态的改变,Western blot检测Survivin、PARP蛋白及细胞外信号调节激酶(ERK)的表达。结果:TSA明显增强了紫杉醇对两种肺癌细胞的抑制率。紫杉醇作用96h对H322细胞的IC50由(48.07±26.12)nmol/L下降至(6.34±5.72)nmol/L,对H1299细胞的IC50由(110.6±38.7)nmol/L下降至(63.7±11.8)nmol/L,差异具有统计学意义...     

褪黑素对苯妥英致畸效应的拮抗作用

背景与目的 :探讨褪黑素(MT)对苯妥英(DPH)诱发小鼠的致畸效应的影响。材料与方法 :于母鼠妊娠GD6 -15 每日灌胃染毒1次不同剂量的MT、DPH ,或两者合并给药 ;GD18 解剖检查 ,观察各项指标。结果 :各实验组在平均活胎数、死胎率、平均着床数、窝平均黄体数及吸收胎数等指标上未见明显差异。高、低剂量DPH组畸胎率分别为18.20 %和45.03 % ;明显高于溶剂对照组。MT与低剂量DPH共处理可明显降低DPH的致畸效应(5 %～12.24 %)。此外 ,MT对低剂量DPH诱发的胎仔体重和身长降低也具有拮抗作用。结论 :MT对DPH诱发的动物发育毒性具有明显的拮抗作用     

Enhanced paclitaxel cytotoxicity and prolonged animal survival rate by a nonviral-mediated systemic delivery of E1A gene in orthotopic xenograft human breast cancer

Paclitaxel (Taxol) is a promising frontline chemotherapeutic agent for the treatment of human breast and ovarian cancers. The adenoviral type 5 E1A gene has been tested in multiple clinical trials for its anticancer activity. E1A has also been shown to sensitize paclitaxel-induced killing in E1A-expressing cells. Here, we show that E1A can sensitize paclitaxel-induced apoptosis in breast cancer cells in a gene therapy setting by an orthotopic mammary tumor model. We first showed that expression of E1A enhanced in vitro paclitaxel cytotoxicity, as compared to the control cells. We then compared the therapeutic efficacy of paclitaxel between orthotopic tumor models established with vector-transfected MDA-MB-231 (231-Vect) versus 231-E1A stable cells, using tumor weight and apoptotic index (TUNEL assay) as the parameters. We found paclitaxel was more effective in shrinking tumors and inducing apoptosis in tumor models established with stable 231-E1A cells than the control 231-Vect cells. We also tested whether E1A could directly enhance paclitaxel-induced killing in nude mice, by using a nonviral, surface-protected cationic liposome to deliver E1A gene via the mouse tail vein. We compared the therapeutic effects of E1A gene therapy with or without Taxol chemotherapy in the established orthotopic tumor model of animals inoculated with MDA-MB-231 cells, and found that a combination of systemic E1A gene therapy and paclitaxel chemotherapy significantly enhanced the therapeutic efficacy and dramatically repressed tumor growth (P < .01). In addition, survival rates were significantly higher in animals treated with combination therapy than in the therapeutic control groups (both P < .0001). Thus, the E1A gene therapy indeed enhances the sensitivity of tumor cells to chemotherapy in a gene therapy setting and, the current study provides preclinical data to support combination therapy between E1A gene and chemotherapy for future clinical trials.     

顺铂和紫杉醇对CIK 细胞杀伤食管癌细胞活性的影响及其分子机制研究*

目的：研究紫杉醇、顺铂对人食管癌EC9706细胞NKG 2D 配体表达及CIK 细胞杀伤活性的影响,探讨相关分子机制。方法：MTT 法测定紫杉醇、顺铂对EC9706细胞的24h 半数抑制浓度（IC 50）。 流式细胞仪检测1/ 2 IC 50浓度紫杉醇、顺铂作用前、后EC9706细胞NKG 2D 配体的表达。乳酸脱氢酶释放法检测效靶比2 0 ：1、3 0 ：1 时,CIK 细胞对1/ 2 IC 50浓度紫杉醇、顺铂作用前、后EC9706细胞的杀伤活性。荧光定量PCR 法检测1/ 2 IC 50浓度紫杉醇、顺铂作用EC9706细胞24h 前、后DNA 损伤修复基因（ATM 、ATR 、CHK 1、CHK 2、P 53）表达的变化。结果：紫杉醇、顺铂的24h 半数抑制浓度分别为10、5 μ g/mL 。1/ 2 IC 50浓度紫杉醇作用24h后,EC9706细胞MICB、ULBP2、ULBP3 表达均明显增强（P < 0.05）,MICA、ULBP1 表达无显著性变化（P > 0.05）;1/ 2 IC 50浓度顺铂作用24h 后,EC9706细胞 MICA、MICB、ULBP2、ULBP3 表达均明显增强（P < 0.05）,ULBP1 表达无显著性变化（P > 0.05）。效靶比 20 ：1、30 ：1 时,CIK 细胞对 1/ 2 IC 50浓度紫杉醇、顺铂作用后的 EC9706细胞的杀伤活性均明显增强（P < 0.05）。1/ 2 IC 50浓度紫杉醇作用 24h后,DNA 损伤修复基因表达均无显著性变化（P > 0.05）;1/ 2 IC 50浓度顺铂作用24h 后,ATM 、ATR 、CHK 1、CHK 2 基因表达均明显增加（P < 0.05）,P 53基因表达无显著性变化（P > 0.05）。 结论：顺铂、紫杉醇均可增强CIK 细胞的杀伤活性,其分子机制可能与激活DNA 损伤修复基因,进而增加NKG 2D 配体表达有关。