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PubMed2001

Expression of multidrug resistance associated transporters (MDR1, MRP1, LRP and BCRP) in porcine oocyte.

Transporters such as P-glycoprotein (MDR1), multidrug resistance protein 1 (MRP1), lung resistance-related protein (LRP) and breast cancer resistance protein (BCRP) are associated with multidrug resistance in various carcinoma cell lines. The expression of these molecules has been also characterized in human normal tissues. However, the expression of these molecules in oocyte is still unclear. In order to obtain more insight into the physiological role of these transporters, their expression in porcine oocyte were examined by reverse transcriptase-polymerase chain reaction. MDR1, MRP1 and LRP genes, but not BCRP gene were found to be expressed in porcine oocyte. After the subcloning and sequence analysis of MDR1, MRP1 and LRP genes, the high homology of these transporters were observed between porcine and human gene. These findings suggest that MDR1, MRP1 and LRP play an important physiological role(s) in an oocyte.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Sequential overexpression of LRP and MRP but not P-gp 170 in VP16-selected A549 adenocarcinoma cells.

Chemoresistance remains the major obstacle to successful therapy of lung cancer. In order to understand drug resistance mechanisms, the expression of three proteins involved in multidrug resistance (P-gp, MRP and LRP) was studied, using the non-small cell lung cancer (NSCLC) A549 cell line. In addition, 3 levels of resistance were obtained by continuous exposure of cells to etoposide (VP16), which led to a 22-fold increase of the resistance index. The wild-type A549 strongly expressed the LRP protein while MRP protein was found at a moderate level. Induction of resistance paralleled an increase of the expression of the mrp gene and a decrease of the lrp gene; the mdr1 gene was not expressed. Taken together, these results indicate that intrinsically resistant NSCLC cells exhibit a complex pattern of MDR proteins, still susceptible to evolve under treatment. Such a fact would have to be considered in clinical situations.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

Doxorubicin-resistant variants of human prostate cancer cell lines DU 145, PC-3, PPC-1, and TSU-PR1: characterization of biochemical determinants of antineoplastic drug sensitivity.

Intrinsic and acquired antineoplastic drug resistance remain a major problem for advanced prostate cancer treatment. In order to characterize mechanisms of anti-neoplastic drug resistance in human prostate cancer cell lines, resistant sublines of four of the commonly studied prostate cancer cell lines (DU 145, PC-3, PPC-1, and TSU-PR1) were selected following exposure to increasing concentrations of doxorubicin (from 10-1000 nM). Sensitivity patterns of the parent and doxorubicin-resistant sublines to various anti-neoplastic drugs, including adriamycin, amsacrine, etoposide, camptothecin, vinblastine, vincristine, fluorodeoxyuridine, and melphalan, were determined using a sulforhodamine B growth inhibition assay. The expression of three well-described antineoplastic drug resistance proteins, P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), and lung resistance protein (LRP), was assessed using reverse transcriptase-polymerase chain reaction (RT-PCR) assays specific for each of the mRNA species, and using immunocytochemical staining procedures specific for each of the polypeptides. All four of the doxorubicin-selected prostate cancer cell lines exhibited a multidrug resistance phenotype; administration of verapamil restored doxorubicin sensitivity for each of the drug resistant sublines. Although significant MDR1 expression was not detected in any of the parent cell lines before drug exposure by RT-PCR analysis or by immunocytochemistry, both MDR1 mRNA and P-gp protein were expressed by the TSU-PR1 Adr 1000 subline. In contrast, MRP mRNA and protein were present in each of the prostate cancer cell lines before doxorubicin-selection, and an increase in MRP expression appeared to accompany the acquisition of drug resistance in DU 145, PC-3, and PPC-1 doxorubicin-resistant sublines. LRP was variably expressed by each of the parent and resistant cell lines. These data suggest that drug resistance in human prostate cancer may be multifactorial, with MRP and LRP frequently expressed in prostate cancer cells before antineoplastic drug treatment and P-gp expression occasionally acquired after drug exposure.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2002

Up-regulation of drug resistance-related vaults during dendritic cell development.

P-glycoprotein (Pgp) and vaults are associated with multidrug resistance in tumor cells, but their physiological functions are not yet clear. Pgp, the prototypical transmembrane transporter molecule, may also facilitate the migration of skin dendritic cells (DC). Vaults--ribonucleoprotein cell organelles, frequently overexpressed in Pgp-negative drug-resistant tumor cells--have also been associated with intracellular transport processes. Given the pivotal role of DC in dealing with exposure to potentially harmful substances, the present study was set out to examine the expression of Pgp and vaults during differentiation and maturation of DC. DC were obtained from different sources, including blood-derived monocytes, CD34(+) mononuclear cells, and chronic myeloid leukemia cells. Whereas flow cytometric and immunocytochemical analyses showed slightly augmented levels of Pgp, up-regulation of vault expression during DC culturing was strong, readily confirmed by Western blotting, and independent of the source of DC. In further exploring the functional significance of vault expression, it was found that supplementing DC cultures with polyclonal or mAbs against the major vault protein led to lower viabilities of LPS- or TNF-alpha-matured monocytes-DC. Moreover, expression of critical differentiation, maturation, and costimulatory molecules, including CD1a and CD83, was reduced and their capacity to induce Ag-specific T cell proliferative and IFN-gamma release responses was impaired. These data point to a role for vaults in both DC survival and functioning as APC.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2003

[Lung resistance protein analysis in testicular cancer].

Germ cell testicular cancers are well-curable neoplasms, because total remission can be achieved in about 80% of the cases. However, 15-20% of the patients die due to drug resistance (DR). A number of mechanisms of the multidrug resistance phenotype are known, including MDR/P-glycoprotein (P-gp) and the so-called multidrug resistance associated protein (MRP). Lung Resistance Protein (LRP) is an ATP dependent membrane transporter protein associated with MDR. In our present work we studied the expression of LRP in testicular cancers. LRP expression was determined by immunohistochemistry (IH), Western blot (WB) and RT-PCR techniques. Clinical resistance was defined in accordance with the clinical oncologic rules. In 29 (41%) of 70 primary testicular tumours and in 22 (63%) of 35 cases, elevated LRP levels were established by IH and WB, respectively. In the latter 63%, the LRP mRNA levels were elevated as well. Six cases of the 15 seminomas and 23 cases of the nonseminomatous germ cell tumours (NSGCT) proved to be positive. No relationship was demonstrated between LRP expression and the stage of the disease. Despite the LRP positivity of 6 tumour samples, all of the seminomas proved sensitive. Of the 39 sensitive NSGCT, 27 cases were LRP-negative, whereas 11 tumour samples of 16 patients belonging to the resistant group proved LRP-positive (p=0.04). The authors concluded that the expression of LRP is responsible for clinical drug resistance in non-seminomatous testicular cancer patients.

Adult↗
PubMed1999

Frequency and clinical significance of the expression of the multidrug resistance proteins MDR1/P-glycoprotein, MRP1, and LRP in acute myeloid leukemia: a Southwest Oncology Group Study.

Therapeutic resistance is a major obstacle in the treatment of acute myeloid leukemia (AML). Such resistance has been associated with rapid drug efflux mediated by the multidrug resistance gene 1 (MDR1; encoding P-glycoprotein) and more recently with expression of other novel proteins conferring multidrug resistance such as MRP1 (multidrug resistance-associated protein 1) and LRP (lung resistance protein). To determine the frequency and clinical significance of MDR1, MRP1, and LRP in younger AML patients, we developed multiparameter flow cytometric assays to quantify expression of these proteins in pretreatment leukemic blasts from 352 newly diagnosed AML patients (median age, 44 years) registered to a single clinical trial (SWOG 8600). Protein expression was further correlated with functional efflux by leukemic blasts [assessed using two substrates: Di(OC)(2) and Rhodamine 123] and with the ability of MDR-reversing agents to inhibit efflux in vitro. MDR1/P-glycoprotein expression, which was highly correlated with cyclosporine-inhibited efflux, was noted in only 35% of these younger AML patients, distinctly lower than the frequency of 71% we previously reported in AML in the elderly (Blood 89:3323, 1997). Interestingly, MDR1 expression and functional drug efflux increased with patient age, from a frequency of only 17% in patients less than 35 years old to 39% in patients aged 50 years (P =.010). In contrast, MRP1 was expressed in only 10% of cases and decreased with patient age (P =. 024). LRP was detected in 43% of cases and increased significantly with increasing white blood cell counts (P =.0015). LRP was also marginally associated with favorable cytogenetics (P =.012) and French-American-British (FAB) AML FAB subtypes (P =.013), being particularly frequent in M4/M5 cases. Only MDR1/P-glycoprotein expression and cyclosporine-inhibited efflux were significantly associated with complete remission (CR) rate (P(MDR1) =.012; P(efflux) =.039) and resistant disease (RD; P(MDR1) =.0007; P(efflux) =.0092). No such correlations were observed for MRP1 (P(CR) =.93; P(RD) =.55) or LRP (P(CR) =.50; P(RD) =.53). None of these parameters were associated with overall or relapse-free survival. Unexpectedly, a distinct and nonoverlapping phenotype was detected in 18% of these cases: cyclosporine-resistant efflux not associated with MDR1, MRP1, or LRP expression, implying the existence of other as yet undefined efflux mechanisms in AML. In summary, MDR1 is less frequent in younger AML patients, which may in part explain their better response to therapy. Neither MRP1 nor LRP are significant predictors of outcome in this patient group. Thus, inclusion of MDR1-modulators alone may benefit younger AML patients with MDR1(+) disease.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Anticancer drug sensitivity and expression of multidrug resistance markers in early passage human sarcomas.

We have established new human sarcoma lines and examined their sensitivity to common antitumor drugs and expression of putative multidrug resistance (MDR) proteins. Eighty-two sarcoma samples were transplanted in nude mice. Fourteen of these sarcomas were established as tumor cell lines. We determined a chemosensitivity profile to antitumor drugs (MDR drugs = doxorubicin, mitoxantrone, and vincristine; non-MDR drugs = cisplatin, ifosfamide, and bleomycin) for each tumor line in vivo. Response to chemotherapy with doxorubicin and ifosfamide was observed in 30-50% of these tumor lines. Our results obtained with xenotransplants are similar to the results documented in clinical trials in which doxorubicin and ifosfamide are effective in 30-50% of the patients. Furthermore, we examined expression of MDR-relevant markers like P-glycoprotein, MDR-associated protein, lung resistance protein, and mdr1 mRNA in these xenotransplants. A relationship between mdr1 mRNA expression and response to doxorubicin was demonstrated in >90% of our tumor lines. In six sarcomas with mdr1 mRNA expression, five were resistant against doxorubicin and cross-resistant against several other drugs, whereas from eight sarcomas, which lacked detectable mdr1 mRNA, seven were sensitive to doxorubicin and other drugs. We found lung resistance protein or MDR-associated protein expressed in three resistant and mdr1 mRNA-positive sarcomas. These results demonstrate that mdr1 mRNA expression is a putative marker for drug resistance in our sarcoma lines. We conclude, therefore, that inherent P-glycoprotein expression might be also responsible for drug resistance occurring in treatment of patients with sarcomas. The established tumor lines are useful for additional investigations on mechanisms of drug resistance in sarcomas and as models for preclinical screening of new antitumor drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1999

Expression of the lung resistance protein predicts poor outcome in patients with multiple myeloma.

Expression of the lung resistance protein (LRP) is associated with resistance to various anticancer drugs including melphalan and, therefore, may affect the clinical outcome in multiple myeloma (MM). To determine the clinical significance of LRP, we have compared LRP expression in bone marrow plasma cells with clinical parameters including response to chemotherapy and survival of previously untreated patients with MM (n = 72). LRP expression immunocytochemically assessed by means of the LRP-56 monoclonal antibody was positive (> or =10% staining plasma cells) in 44 (61%) samples. There was no correlation between LRP expression and age, sex, type of the paraprotein, serum creatinine, stage, beta2-microglobulin, serum lactate dehydrogenase, or C-reactive protein. However, LRP expression was more frequently observed in patients with a p53 deletion than in those without such a deletion (P = 0.01). The overall response rate for all of the patients evaluable for response to induction chemotherapy (n = 58) was 67%. The response rate was 87% for patients without LRP expression but only 54% for patients with LRP expression (P = 0.01). Kaplan-Meier analysis revealed that patients with LRP expression had a shorter overall survival (median, 33 months) than those without LRP expression (median not reached; P = 0.04). These data show that LRP expression is an important marker for clinical drug resistance and predicts a poor outcome in MM.

Adult↗
PubMed1999

Drug resistance-associated markers P-glycoprotein, multidrug resistance-associated protein 1, multidrug resistance-associated protein 2, and lung resistance protein as prognostic factors in ovarian carcinoma.

Intrinsic and/or acquired resistance to chemotherapy is the major obstacle to overcome in the treatment of patients with ovarian carcinoma. The aim of the present study was to investigate the prognostic value of drug resistance-associated proteins P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), canalicular multispecific organic anion transporter (c-MOAT/MRP2), and lung resistance protein (LRP) in ovarian carcinoma. Expression of P-gp, MRP1, MRP2, and LRP was determined by immunohistochemistry of frozen tissue sections of 115 ovarian carcinoma patients and related to clinicopathological factors, response to chemotherapy, and progression-free survival. P-gp expression was observed in 20 of 115 (17%), MRP1 in 51 (44%), MRP2 in 19 (16%), and LRP in 85 (74%) tumors. Expression of MRP1 was related to MRP2 (P<0.0001) and P-gp (P<0.001) expression, whereas LRP expression was more frequently observed in patients with early stage (P<0.01), lower grade (P<0.05), and smaller residual tumor (P<0.05). Early stage (P<0.001), smaller residual tumor (P<0.001), and lower differentiation grade (P<0.05) were related to longer (progression-free) survival. P-gp, MRP1, MRP2, and LRP expression were neither related to response to first-line chemotherapy in 59 evaluable patients nor to progression-free survival in all patients. On multivariate analysis, only stage and residual tumor were independent prognostic factors for survival. In conclusion, in ovarian carcinoma, MRP1 expression is associated with MRP2 and P-gp expression, whereas LRP expression is associated with favorable clinicopathological characteristics. Assessment of P-gp, MRP1, MRP2, or LRP does not allow prediction of response to chemotherapy or survival in ovarian carcinoma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Expression of the lung resistance protein (LRP) in primary breast cancer.

BACKGROUND: To determine the clinical significance of the lung resistance protein (LRP) in breast cancer, we have studied its expression in primary breast carcinomas (n = 99) and assessed the association of this expression with clinical parameters of the patients. MATERIALS AND METHODS: LRP expression was immunohistochemically determined by means of the monoclonal antibody LRP-56 on frozen tumor sections. RESULTS: LRP expression was negative in 12%, low in 20%, intermediate in 47% and high in 21% of the carcinomas. LRP expression was independent of age of the patients, histology, tumor grade, estrogen receptor as well as progesterone receptor status, tumor size and lymph node involvement. Kaplan-Meier analyses revealed that both overall survival and disease-free survival were independent of the degree of LRP expression. CONCLUSIONS: LRP is frequently expressed in breast carcinomas, but is neither associated with known prognostic factors, nor a prognostic factor by itself.

Adult↗
PubMed1999

[Expression and prognostic value of the drug resistance markers P-gp, Mrp1, Mrp2, and Lrp in ovarian carcinoma].

BACKGROUND: Intrinsic and/or acquired chemoresistance is the major obstacle to overcome in the treatment of patients with ovarian carcinoma. The aim of the present study was to investigate the prognostic value of drug resistance associated proteins P-glycoprotein (P-gp), multidrug resistance related protein (Mrp1), canalicular multispecific organic anion trans-porter (c-MOAT or Mrp2) and lung resistance protein (Lrp) in ovarian carcinoma. METHODS: Expression of P-gp, Mrp1, Mrp2 and Lrp was determined by immunohistochemistry of frozen tissue sections of 115 ovarian carcinoma patients and associated to clinico-pathological factors, response to chemotherapy and (progression free) survival. RESULTS: Expression of P-gp was observed in 20 out of 115 (17%), Mrp1 in 51 out of 115 (44%), Mrp2 in 19 out of 115 (16%) and Lrp in 85 out 115 (74%) tumors. Expression of Mrp1 was related to Mrp2 (p < 0.0001) and P-gp (p < 0.001) expression, while Lrp expression was more frequently observed in patients with stage I/II versus stage III/IV tumors (p < 0.01), grade I/II versus III tumors (p < 0.05) and residual tumor < 2 cm versus > 2 cm after laparotomy (p < 0.05). Lower stage (p < 0.001), small residual tumor after first laparotomy (p < 0.001) and lower differentiation grade (p < 0.05) were related to longer (progression free) survival. P-gp, Mrp1, Mrp2, and Lrp expression was neither related to response to first line chemotherapy (59 evaluable patients) nor to (progression free) survival (all patients). On multivariate analysis only stage and residual tumor after first laparotomy were independent prognostic factors for (progression free) survival. CONCLUSIONS: In ovarian carcinoma Mrp1 expression is associated with Mrp2 and P-gp expression, while Lrp expression is associated with favorable clinicopathological characteristics. Assessment of P-gp, Mrp1, Mrp2 or Lrp does not allow prediction of response to chemotherapy or (progression free) survival in ovarian carcinoma.

ATP Binding Cassette Transporter, Subfamily B↗
PubMed2000

Intracellular P-glycoprotein expression is associated with the intrinsic multidrug resistance phenotype in human colon adenocarcinoma cells.

The 2 clones, LoVo 5 and LoVo 7, derived from untreated LoVo WT human colon adenocarcinoma cells and exhibiting different sensitivity to doxorubicin (DOX), were compared in order to identify possible determinants of intrinsic drug resistance. A multidrug resistant variant cell line, selected from LoVo WT cells by continuous exposure to DOX (LoVo DX), was also included in the study. Analysis of the expression and organization of cytoskeletal elements by flow cytometry and fluorescence microscopy evidenced a positive correlation between vimentin expression and DOX resistance in LoVo 7 and LoVo DX cells, whereas differences in actin, tubulin or cytokeratin did not seem to relate to drug response. The expression and localization of different drug transporters commonly implicated in drug resistance, i.e., the MDR1 gene product P-glycoprotein (P-gp), the multidrug resistance-related protein MRP and the lung resistance-related protein LRP were also investigated by means of flow cytometry and fluorescence microscopy, following labeling with specific monoclonal antibodies. Surface expression of P-gp was only detected in LoVo DX cells, which also exhibited increased MRP and LRP protein levels. However, significant amounts of P-gp were found at intracellular sites in the intrinsically resistant LoVo 7 clone. Modulation of P-gp function by cyclosporin A was found to alter DOX accumulation and efflux in LoVo 7 cells, indicating that intracellular P-gp plays a functional role in drug trafficking and suggesting possible implications in determining the intrinsic resistance displayed by this clone.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

[Resistance of cells in hematopoietic malignancies to cytostatic agents. Part 1].

Resistance to cytotoxic drugs is a serious drawback in the treatment of patients with tumours, both of the haemopoietic and non-haemopoietic origin. The cytotoxic effect of drugs on the malignant cells manifests as the process of apoptosis. In the resistant malignant cells, apoptosis becomes prevented by several mechanisms. The multidrug resistance (MDR) is one of the principal mechanisms when the cancer cells develop resistance to multiple chemically and functionally unrelated cytotoxic compounds. The decrease of the cytotoxic drug concentration at the molecular target site may come from activation of some efflux membrane systems participating in the transport of cytotoxic drugs out of the cell (e.g. Pgp, MDR, and LRP). Another mechanism of resistance is the increased enzymatic detoxification of the drug by glutathion-S-transferase system. Changes in the molecular target of the cytotoxic drug such as topoisomerase molecule can be also responsible for the resistance. At least two additional mechanisms of resistance of tumour cells were identified. Resistance can come from either deregulation of proapoptic mechanisms in tumour cells or by increased activity of reparation processes which control the damaged molecule of DNA. Several methods that detect the cause of resistance in distinct cell populations have been developed. The great effort is now focused on both the detection of mechanisms of the resistance and on the clinical procedures of overcoming the resistance to cytotoxic drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Expression of multidrug resistance-related markers in gastric cancer.

BACKGROUND: To detect the expression of glutathione S-transferase Pi(GST-pi), multidrug resistance-associated protein (MRP), lung-resistance protein(LRP), multidrug resistance gene1 (MDR1) and MGr1 antigen(MGr1-Ag) in the patients with primary gastric cancer and without any prior chemotherapy and to evaluate the correlations between them. PATIENTS AND METHODS: The expression of GST-pi, MRP, LRP and MDR1 in cancer tissue and the adjacent non-cancerous tissue from 50 patients was examined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression of MGr1-Ag in these tissues was also examined by immunohistochemistry. RESULTS: The positive rate of GST-pi mRNA, MRP mRNA, LRP mRNA, MDR1mRNA and MGr1-Ag in gastric cancer tissue was 36.00%, 12.00%, 10.00%, 10.00% and 18.00% respectively. The overall positive rate of their expression was 58.00%. Clinicopathological factors were not significantly related to their expression. No significant correlation was observed between these markers. CONCLUSION: These MDR markers are differently over-expressed and no coexpression exists in gastric cancer. MGr1-Ag was a novel MDR protein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Expression of the lung resistance protein in primary colorectal carcinomas.

To assess whether the lung resistance protein (LRP) is of clinical significance in colorectal carcinomas, we immunohistochemically determined LRP expression of colorectal carcinoma specimens (n = 68) by means of the monoclonal antibody LRP-56 and compared this expression with clinical parameters. LRP expression was negative in 7 (10%), low in 36 (52%) and high in 25 (38%) carcinomas. LRP expression was independent of histological grade, tumor size, lymph node involvement and distant metastasis. Survival of the patients with LRP-positive tumors was similar to the survival of patients with LRP-negative tumors. However, patients with high LRP expression in their carcinomas had a prolonged survival. Thus LRP is frequently expressed in colorectal carcinomas and high expression might indicate improved survival.

Aged↗
PubMed2001

Expression of P-glycoprotein, multidrug resistance-associated protein 1, and lung resistance-related protein in human soft tissue sarcomas before and after hyperthermic isolated limb perfusion with tumor necrosis factor-alpha and melphalan.

BACKGROUND: Multidrug resistance (MDR) is associated with expression of P-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and lung resistance-related protein (LRP). Tumor necrosis factor (TNF-alpha) is able to modify the expression of these three proteins in different cell types. The effect of TNF-alpha in the clinical situation on patients with soft tissue sarcomas (STS) is indeterminate. METHODS: Thirty-seven patients with a locally advanced extremity STS underwent hyperthermic isolated limb perfusion (HILP) with TNF-alpha and melphalan; 15 patients received additional interferon gamma. Clinical and histologic responses were documented and used to define the overall response. Samples before and after HILP were analyzed immunohistochemically for P-gp, MRP1, and LRP. Samples were scored as negative or positive (< or = 5% or > 5% positive tumor cells). RESULTS: Six patients had an overall complete response, 25 patients had a partial response, and 4 patients with STS revealed no change; in 2 patients, the response remained unclear. The percentage STS samples that were positive for all three proteins dropped from 92% before HILP to 85% after HILP. P-gp positive samples were encountered more often than MRP1 positive samples (P < 0.05). The percentage of samples that were negative for all three MDR proteins increased after HILP from 6% to 16%. MDR status had no significant correlation with tumor response. CONCLUSIONS: HILP with TNF-alpha and melphalan results in excellent overall tumor response in patients with locally advanced STS. STS more often are positive for P-gp than for MRP1. MDR status in patients with STS is not predictive for tumor response after HILP. Data from the current study suggest that the combination of TNF-alpha and melphalan does not induce MDR positive STS: a result with clinical importance when consecutive, adjuvant, doxorubicin-containing chemotherapy is considered.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed2000

[Establishment of cisplatin-induced multidrug resistant human epithelial ovarian cancer cell line 3AO/cDDP and its expressions of multidrug resistance proteins].

OBJECTIVE: To establish multidrug resistant ovarian cancer cell line 3AO/cDDP by exposing parent cell line intervally and repeatedly to high-level concentration of cisplatin, and to detect expressions of lung resistance protein (LRP), multidrug resistance-associated protein(MRP) and P-glycoprotein (P-gp). METHODS: Using the corresponding dose calculated from clinical chemotherapy, we established 3AO/cDDP, with 3AO exposed intervally and repeatedly to high-level concentration of cisplatin at 10 micrograms/ml for 24 hours each time; LRP, MRP and P-gp expressions were detected with flow cytometry(FCM). RESULTS: 3AO/cDDP was established after 4.5 months with stable resistance and the drug resistant index was 1.62 which was similar to clinical resistance degree. Low expression levels of MRP and P-gp were found in both 3AO and 3AO/cDDP, and no statistical difference between the two lines (P > 0.05). However, LRP expression level in 3AO/cDDP was significantly higher than that in 3AO with FCM detection (P < 0.01). CONCLUSIONS: 3AO/cDDP, induced by exposing 3AO to high-level concentration of cisplatin intervally and repeatedly, is an ideal model for investigation of cisplatin resistance. Cisplatin resistance in 3AO/cDDP could be related to high LRP expression and be not associated with MRP or P-gp.

ATP Binding Cassette Transporter, Subfamily B, Mem↗