Lung Resistance Protein Expression Research Articles

Abstract 1714: Chemoresistance in patients with papillary serous carcinoma of the ovary

Abstract The majority of patients with ovarian carcinoma present at an advanced stage, with metastatic disease throughout the peritoneal cavity. Therefore, patients commonly undergo platinum-based chemotherapy. Even though the initial response rates can be high, the majority of patients will have recurrent disease and the 5-year survival rate is only 10-20%. The human lung resistance protein (LRP) is a multidrug resistance protein that has been shown to be overexpressed in models of chemotherapy resistance, but has not been adequately explored in platinum-resistant epithelial ovarian cancer (EOC). The primary aim of this study was to compare LRP expression in the tumor cells from ascitic fluid with tumor cells from omental metastasis in chemotherapy-naïve patients with advanced EOC. The secondary aim was to explore possible mechanisms in which LRP might cause drug resistance. After IRB approval, patient ascites and metastatic implants were collected and evaluated for platinum sensitivity and expression of LRP, phospho-ERK, and AKT using western blots and immunohistochemistry (IHC). Both ascites and omental metastatic implants were treated with 50 uM carboplatin for 48 hours and cell viability was analyzed. LRP, phospho-ERK, and AKT were analyzed using IHC on samples treated with 50 uM carboplatin or phosphate buffered saline. Of 20 patients who had matched ascites and omental metastatic implants adequate for analysis, 4 were platinum resistant, 3 were platinum sensitive, and 13 displayed intermediate platinum sensitivity. Overall, the malignant cells in ascites were more resistant to carboplatin than the metastatic implants (p=0.001) and the malignant cells in ascites showed higher expression of LRP than the omental metastatic implants by IHC and western blotting. IHC and western blotting also demonstrated that the malignant cells in ascites had lower expression of phospho-ERK and higher expression of AKT than the metastatic implants. After treatment with 50 uM carboplatin, the platinum resistant patients had decrease in phospho-ERK and an increase in AKT versus the platinum sensitive patients who had an increase in phopho-ERK and a decrease in AKT and LRP. High expression of LRP in the tumor cells in ascitic fluid may indicate platinum resistance prior to initiation of platinum-based chemotherapy. Also, changes in phospho-ERK and AKT following platinum based therapy may indicate the extent of response of EOC to this therapy. Supported in part by the Kaleidoscope of Hope ovarian cancer foundation. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1714. doi:10.1158/1538-7445.AM2011-1714

Efflux Pumps Modulation in Colorectal Adenocarcinoma Cell Lines: The Role of Nuclear Medicine

Introduction: Multidrug resistance (MDR) is one of the major problems of chemotherapy. Overexpression of efflux pumps, such as P-glycoprotein (Pgp), multiple resistance-related protein 1 (MRP-1) and lung resistance protein (LRP) can lead to MDR. Verapamil and L-buthionine-sulfoximine (BSO) are two modulators of these proteins. This study aims to compare 99mTc-Sestamibi transport kinetics in human colorectal adenocarcinoma cell lines, in the presence and absence of the MDR modulators verapamil and BSO. Material and Methods: MDR proteins expression was evaluated in sensitive (WiDr) and resistant (LS1034) human colorectal adenocarcinoma cell lines. Intracellular and plasma membrane Pgp and MRP1, and LRP expression was analyzed by flow-cytometry and western blot. Cellular transport kinetics was assessed using 99mTc-Sestamibi. MDR modulation was evaluated though retention studies in resistant cells after incubation with the modulators. Results: Pgp expression was significantly higher (p≤0.001) in resistant cells. These results were confirmed by western blot analysis. 99mTc-Sestamibi uptake and retention percentage were significantly higher (p99mTc-Sestamibi, there were differences among the MDR modulators used (p99mTc-Sestamibi could indicate MDR phenotype in colorectal adenocarcinoma cells. As the modulators used showed a reversion of the retention profile only for the first minutes, their administration should occur immediately before the administration of cytotoxic drugs.

Tanshinone IIA acts via p38 MAPK to induce apoptosis and the down-regulation of ERCC1 and lung-resistance protein in cisplatin-resistant ovarian cancer cells

Tanshinone IIA is known to induce apoptosis in several types of cancer cells. However, little is known about its activity in chemoresistant cells. The aim of this study was to investigate the anticancer properties of tanshinone IIA in cisplatin-resistant human ovarian cancer COC1/DDP cells in vitro. We used a variety of methods to measure cell viability, the resistance index (RI) of cisplatin, cellular apoptosis, p38 mitogen-activated protein kinase (MAPK) expression and phosphorylation, and the mRNA expression of several genes implicated in drug resistance including survivin, Caspase-3, excision repair cross-complementing gene 1 (ERCC1), multidrug resistance (MDR), lung resistance protein (LRP) and glutathione-S-transferase-π (GST-π). We found that tanshinone IIA time- and dose-dependently inhibited the proliferation of COC1/DDP cells and caused significant apoptosis. Western blotting revealed that tanshinone IIA also increased phospho-p38 MAPK in a time- and dose-dependent manner. After treatment by tanshinone IIA for 48 h, the RI of cisplatin and the mRNA expression of survivin, ERCC1 and LRP were all significantly decreased. Furthermore, blockade of p38 signal transduction decreased apoptotic cell rates and dramatically elevated the mRNA expression of the survivin, ERCC1 and LRP genes. We therefore conclude that tanshinone IIA induces apoptosis and reduces cisplatin resistance in COC1/DDP cells and thus causes significant growth inhibitory effects. This mechanism appears to involve p38-mediated downregulation of survivin, ERCC1 and LRP mRNA expression.

Lung resistance protein and multidrug resistance of gastric cancer

Lung resistance protein (LRP) is a gene which is found early and is closely related to multidrug resistance. LRP is expressed in most normal tissues with secretory function and is involved in secretion and cell detoxification function. LRP can also be seen expressed in malignant tumors including gastric cancer. There is a certain correlation between LRP expression and the prognosis of malignant tumor patients. LRP plays the role of multi-drug resistance mainly by preventing chemotherapy drugs into the nucleus and pumping chemother apy drugs out of the cells. Key words: Stomach neoplasms; Lung resistance protein

Abstract 2688: The expression of lung resistance protein (LRP) in patient ascites predicts platinum resistance in advanced epithelial ovarian carcinoma

Abstract The human lung resistance protein (LRP) is a multidrug resistance protein that has been shown to be overexpressed in numerous chemotherapy resistance models. The precise role of LRP in platinum-resistant epithelial ovarian cancer (EOC) has yet to be fully elucidated. In this study, we sought to determine LRP expression in the tumor cells of ovarian cancer patient ascites of chemotherapy-naïve patients with advanced EOC. After IRB approval was obtained, patient ascites was collected and evaluated for platinum sensitivity, and LRP expression using western blot and immunohistochemistry (IHC). Both patient ascites and primary tumor were treated with 50 uM carboplatin for 48h and cell viability was analyzed. LRP, activated Caspase 3, and tunnel were analyzed using IHC on samples treated with 50uM carboplatin and untreated. A total of 27 patients with advanced-stage EOC undergoing primary cytoreductive surgery at the University of Alabama at Birmingham were consented for the study. Ten patient ascites samples were deemed adequate for analysis. Of these, 3/10 (30%) had increased LRP levels in ascites samples demonstrated by strong IHC staining with capping and confirmed by western blot. These patient samples were platinum resistant as verified by cytotoxicity analysis. Two ascites specimens (20%) lacked LRP expression by IHC and western blot and demonstrated platinum sensitivity on cytotoxicity. Five ascites specimens (50%) displayed intermediate LRP staining and platinum cytotoxicity. Tumor cells in ascites treated with carboplatin had an inverse correlation of LRP staining and activated Caspase 3. There is a strong correlation between LRP expression in the ascites of patients with advanced EOC and platinum resistance in this ex vivo model. This protein may therefore predict poor prognosis disease unlikely to respond to adjuvant platinum therapy. Specifically targeting the LRP in a clinical model may reverse carboplatin resistance. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2688.

Expression of lung resistance protein and multidrug resistance-related protein (MRP1) in pediatric acute lymphoblastic leukemia

Multidrug resistance (MDR) is a phenomenon by which cells become resistant to unrelated chemotherapeutic agents. The prognostic value that lung resistance protein (LRP) and multidrug resistance-related protein 1 (MRP1) have in the setting of pediatric acute lymphoblastic leukemia (ALL) is controversial. The aim of this study was to investigate the expression of LRP and MRP1 and effect on clinical outcome and prognosis. The mRNA expression of LRP and MRP1 were analyzed in leukemic blasts of 34 pediatric ALL patients. LRP and MRP1 mRNA expression were detected in 41.2% and 35.3%, respectively. Eleven (91.7%) of 12 patients without LRP achieved CR compared with 9 (50.0%) of 18 with LRP expression. Similarly, 11 (100%) of 11 patients without MRP1 expression achieved CR compared with 9 (47.4%) of 19 with MRP1 expression and higher LRP expression rate or MRP1 expression rate was present in patients with relapse than MDR genes negative patients. The expression of either of two genes was associated with poorer 2-year survival. Also, patients expressing both genes had poorer outcomes and had worse 2-year survival. We suggest that MDR expression affects complete remission and survival rates in ALL patients. Thus, diagnosis appears to provide prognostic information for pediatric ALL.

Establishment and biological analysis of the EC109/CDDP multidrug-resistant esophageal squamous cell carcinoma cell line

The aim of this study was to establish a stable, drug-resistant esophageal squamous cell carcinoma (ESCC) cell line. The human ESCC cell line EC109 was exposed to cisplatin (CDDP) by pulse treatment to select for the drug-resistant subline, EC109/CDDP cells. The MTT assay was used to test the drug resistance of EC109 and EC109/CDDP cells. In addition, cellular morphological changes were observed using microscopy and the growth curves of the two cell lines were drawn to calculate the doubling time. Furthermore, cell cycle distribution was analyzed by flow cytometry. Finally, RT-PCR was performed to determine the mRNA expression levels of drug-resistant-related genes, multidrug resistance 1 (MDR1), multidrug resistance-associated protein 1 (MRP1), ATP-binding cassette, sub-family G, member 2 (ABCG2), lung resistance protein (LRP), and glutathione S-transferase (GST)-pi in both cell lines. EC109/CDDP cells exhibited increased resistance to CDDP, carboplatin, 5-fluorouracil, taxol, navelbine, irinotecan and etoposide, and changes in morphology, doubling time, and cell cycle distribution were detected as compared with EC109 cells. Although there was no significant difference in MRP1, ABCG2, LRP, and GST-pi expression, MDR1 expression in EC109/CDDP cells was lower than that of EC109 cells. EC109/CDDP cells are a stable, multidrug-resistant ESCC cell line and could serve as an important tool for further research concerning ESCC drug resistance.

Expression and significance of P-gp/mdr1 mRNA, MRP and LRP in non-Hodgkin's lymphoma

To explore the expression and clinical significance of P-glycoprotein (P-gp)/mdr1mRNA, multidrug resistance-associated protein (MRP) and lung resistance protein (LRP) in newly diagnosed non-Hodgkin's lymphoma. mdr1 mRNA of in 41 patients with non-Hodgkin's lymphoma was assayed by semi-quantitative RT-PCR. The expressions of P-gp, MRP and LRP proteins in lymph node viable blasts were identified by flow cytometry. The results were compared with those obtained from control cases, and the correlation of the changes with clinical outcomes was analyzed. (1) Among the 41 cases, the positive expression of P-gp protein was detected in 8 cases, MRP in 7 cases, LRP in 15 cases, and mdr 1 mRNA in 11 cases. (2) The P-gp and LRP levels in NHL were significantly higher than those in control group, but MRP wasn't. The P-gp over-expression was significantly associated with mdr1mRNA (r = 0.396, P = 0.01). No correlation was showed among the expressions of P-gp, MRP and LRP. (3) Patients with P-gp expression had a poorer outcome of chemotherapy than those with P-gp-negative (P = 0.005). P-gp expression was significantly associated with higher clinical stage (P = 0.046) and elevated serum lactate dehydrogenase level (P = 0.032), but not associated with malignant degree (P = 0.298). MRP had no impact on the outcome of chemotherapy (P = 0.212), and wasn't significantly associated with higher clinical stage (P = 0.369), elevated LDH (P = 0.762) and higher malignant degree (P = 0.451). Patients with LRP expression had a poorer outcome of chemotherapy than those LRP-negative (P = 0.012). LRP expression was significantly associated with higher clinical stage (P = 0.0019), elevated LDH (P = 0.02) and higher malignant degree (P = 0.01). The data of this study indicate that P-gp and LRP expressions but not MRP expression are important in the mechanism of drug resistance associated with a poor clinical outcome in previously untreated NHL.

Reversal effect of tyroservatide (YSV) tripeptide on multi-drug resistance in resistant human hepatocellular carcinoma cell line BEL-7402/5-FU

Tyroservatide (YSV) is an active, low-molecular-weight polypeptide that has been shown to have antitumor effects on human hepatocellular carcinoma BEL-7402 cells in vitro and in vivo. Multi-drug resistance (MDR) represents a major obstacle to the success of cancer chemotherapy. To enhance the chemosensitivity of tumor cells, attention has been focused on MDR modulators. In this study, we evaluated the reversal effect of YSV on MDR, and explored its mechanism of action in vitro. Administration of YSV reversed the multi-drug resistance of human hepatocellular carcinoma BEL-7402/5-FU cells significantly. The intracellular accumulation of doxorubicin and Rhodamine-123 (Rh123) were increased, which implied that the function of the P-glycoprotein (P-gp) efflux pump was inhibited by YSV. Moreover, the mRNA and protein expression of multi-drug resistance gene (MDR1) were also decreased by YSV. We observe that lung-resistance protein (LRP) and multi-drug resistance-associated protein (MRP1) each contribute to MDR in BEL-7402/5-FU cells as well. The mRNA and protein expression of LRP were decreased by YSV. No significant change was observed in mRNA expression of MRP1. However, we observe that the MRP1 protein level was reduced after treatment with YSV. These data demonstrate that YSV effectively reverses MDR in BEL-7402/5-FU cells, and that its mechanism of action is associated with the down-regulation of MDR1, MRP1 and LRP expression, as well as the inhibition of P-gp function.

Expression of Multidrug Resistance-Related Proteins p-Glycoproteinglutathione-s-Transferases, Topoisomerase-II and Lung Resistance Protein in Primary Gastric Cardiac Adenocarcinoma

Aim: Multidrug resistance (MDR) is closely correlated to an unfavorable prognosis in various human cancers. However, the clinical significance of the expression of MDR-related proteins p-glycoprotein (PGP), glutathione-s-transferases (GST-π), topoisomerase-II (Topo-II) and lung resistance protein (LRP) in primary gastric cardiac adenocarcinoma (PGCA) remains unclear. In this present study, the total of the four kinds of MDR-related proteins mentioned above were detected by using immunohistochemistry, and their clinical significance in chemoresistance were also investigated. Methods: This retrospective study included 69 resected specimens from patients with PGCA. The expression of PGP, GST-π, Topo-II and LRP in formalin-fixed paraffin-embedded tissue sections was determined by a labelled streptavidin-biotin immunohistochemical technique, and the results were analyzed in correlation with clinicopathological data. None of these patients received chemotherapy prior to surgery. Results: The positive rates of expression of PGP, GST-π, Topo-II and LRP in malignant tissues (49.2%, 75.4%, 68.1% and 58%, respectively) were all higher than that of the normal tissues(0, 30%, 20% and 0, respectively, P < 0.01). PGP expression in tumors that had metastasized was significantly more frequent than in tumors that had not metastasized (67.5% vs 24.1%, P < 0.01). The expression of PGP was closely related with clinicopathologic staging (staging 1/2 vs 3/4, 28.6% vs 58.3%, P < 0.05). No significant correlation was shown between PGP and increasing differentiated degree (40%, 42.4% and 61.5%, P > 0.05). GST-π expression status progressively increased with increasing differentiated degree (40%, 75.8% and 88.5%, P < 0.05) and clinicopathologic stage (staging 1/2 vs 3/4, 57.1% vs 83.3%, P < 0.05). In addition, a significant positive correlation was also observed between GST-π and lymphatic metastasis (with vs. without metastasis, 87.5% vs 58.6%, P < 0.05). The expression of Topo-II was associated with increasing differentiated degree (33.3%, 69.7 and 80.7%, P < 0.01). No significant differences with Topo-II expression were found in relation to the clinicopathologic stage (staging 1/2 vs 3/4, 57.1% vs 72.9%, P > 0.05) and lymphatic metastasis (with vs. without metastasis, 65.0% vs 72.4%, P > 0.05). Moreover, a significant difference with the expression of LRP was found in relation to the clinicopathologic stage (staging 1/2 vs 3/4, 38% vs 66.6%, P < 0.05), and lymphatic metastasis (with vs without metastasis, 70.0% vs 41.4%, P < 0.05). Comparing the well, moderately and poorly differentiated cohort, a non-statistical increasing trend towards LRP expression status was noted (50.0%, 54.5% and 65.3%, respectively, P > 0.05). Besides, the co-expression of all four tested MDR-related proteins also existed. The positive rates of co-expression of PGP and GST-π, PGP and Topo-II, PGP and LRP, GST-π and Topo-II, LRP and GST-π, LRP and Topo-II, PGP, GST-π, Topo-II and LRP in malignant cells were 23.2%, 15.9%, 11.6%, 13.0, 26.1, 7.24, 5.8, respectively. Conclusions: MDR-related proteins PGP, GST-π, Topo-II α and LRP are involved in multiple mechanisms of drug resistance in PGCA. Combined determination of PGP, GST-π, Topo-II and LRP may be prospectively valuable for optimizing the chemotherapy regimes, developing high quality anti-cancer drugs, and further predicting the outcomes of those patients with PGCA.

TC-99m MIBI Spect Imaging in Patients With Lung Carcinoma

Multidrug-resistance (MDR) phenotype concerns altered membrane transport that results in lower cell concentrations of cytotoxic drug in many cancer types, including lung cancer, and is related to the overexpression of a variety of proteins that act as adenosine triphosphate-dependent extrusion pumps. Tc-99m Sestamibi (MIBI) is a transport substrate for P-glycoprotein (Pgp) pump. In this study, we assessed the uptake and clearance of technetium-99m-2-hexakis 2-methoxyisobutylisonitrile (Tc-99m MIBI) from the tumor and its correlation with messenger RNA (mRNA) levels of Pgp, MDR-associated protein (MRP1), and lung resistance protein (LRP) in lung carcinoma. This study was carried out on 19 patients (mean age, 60.1 +/- 2.07 years) with advanced-stage lung carcinoma. The tumor samples obtained by bronchoscopy were assessed to estimate the levels of Pgp, MRP1, and LRP expression on mRNA level by quantitative real-time reverse-transcription polymerase chain reaction. Tc-99m MIBI chest imaging was performed 15 and 180 minutes after injection of 740 MBq Tc-99m MIBI. The early (T/Be) and delayed (T/Bd) Tc-99m MIBI uptakes and washout rate (WR) of Tc-99m MIBI from the tumor were measured. No correlation was found between the T/Be Tc-99m MIBI uptake of tumors (T/Be) and the levels of Pgp mRNA, MRP1 mRNA, and LRP mRNA by reverse-transcription polymerase chain reaction. There was a correlation between the mean T/Bd Tc-99m MIBI uptake and Pgp expression of the tumors (P = 0.001, Spearman rho = - 0.702). There was a correlation between the WR of Tc-99m MIBI from the tumor and Pgp expression of the tumor (P = 0.000, Spearman rho = 0.875). Washout rate of Tc-99m MIBI was not related to the levels of MRP1 mRNA (P = 0.93, Spearman rho = 0.02) or LRP mRNA (P = 0.47, Spearman rho = 0.177). Increased WR of Tc-99m MIBI is related in Pgp over expression of the tumor. Tc-99m MIBI single photon emission computed tomography imaging may be a functional probe of overexpression of Pgp in patients with lung carcinoma. However, Tc-99m MIBI single photon emission computed tomography imaging cannot be used to identify the MDR involved in the MRP1 or LRP in these patients.

Expression of Multidrug Resistance 1 (MDR1), Multidrug Resistance-Related Protein 1 (MRP1), Lung Resistance Protein (LRP), and Breast Cancer Resistance Protein (BCRP) Genes and Clinical Outcome in Childhood Acute Lymphoblastic Leukemia

The aim of this prospective study was to analyze the expression of messenger RNA of genes, such as MDR1, MRP1, BCRP, and LRP, implicated in the mechanism of multidrug resistance (MDR) in relation to the response to induction chemotherapy and relapse and these genes' correlation with each other and with pretreatment laboratory and clinical characteristics. We prospectively studied 49 children (26 boys and 23 girls) with acute lymphoblastic leukemia (ALL) (median age, 5.5 years; range, 15 months to 12.5 years) who were treated with the BFM95 chemotherapy protocol. We used bone marrow mononuclear cells from 7 healthy children as controls. The expression of MDR genes and the beta-actin housekeeping gene was detected by the reverse transcription-polymerase chain reaction with the appropriate primers. The mean expression of each MDR gene was significantly higher in the patients than in the control group (P < .01). We found statistically significant correlations between MRP1 and LRP expression and between MRP1 or LRP expression and MDR1 expression (P < .05). High expression for the MDR1 gene was found in 18 patients (36.7%), and their prognoses were significantly worse than those with low expression (event-free survival, 55.56% versus 86.67%; P = .03, log-rank test). Expression of each of the MDR genes was independent of the initial white blood cell count, immunophenotype, National Cancer Institute risk classification, and prednisone response. Interestingly, MDR1 expression was significantly higher at relapse than at diagnosis for 4 sample pairs. Evaluation of MDR1 expression at diagnosis of childhood ALL may contribute to the early identification of patients at risk of treatment failure.

MDR1, MRP1 and LRP expression in patients with untreated acute leukaemia: Correlation with 99mTc-MIBI bone marrow scintigraphy

Chemotherapy failure linked to multidrug-resistance (MDR) plays an important role in many cancer types, including leukaemia. It is believed that overexpression of some of membrane or intracellular proteins confers the MDR phenotype to cancer cells. (99m)Tc-sestamibi (MIBI) is a transport substrate for the Pgp pump. We assessed the bone marrow uptake of (99m)Tc-MIBI and its correlation with messenger RNA (mRNA) levels of MDR1, multidrug-resistance associated protein-1 (MRP1) and lung resistance protein (LRP) in acute leukaemia. A total of 26 patients (age range 17-72 years; mean age 51.88+/-2.52 years) with newly diagnosed acute leukaemia were included in the study. The expression of MDR1, MRP1 and LRP on mRNA levels were assessed by quantitative RT-PCR in the blast cells. The MIBI uptake in the bone marrow was evaluated using a quantitative scoring system with determination of the tumour-to-background ratios for the bone marrow areas. The correlation between the quantitative RT-PCR results and MIBI uptake was analysed by using Spearman's rank correlation coefficients with two-tailed test of significance. There was an inverse relationship between (99m)Tc-MIBI uptake of bone marrow and both mRNA levels of MDR1 and MRP1 (P=0.000, r= -0.733 and P=0.001, r= -0.610, respectively). No correlation was found between MIBI uptake and mRNA levels of LRP. Increased expression of MDR1 and MRP1 correlates with a low accumulation of (99m)Tc-MIBI in bone marrow areas in patients with acute leukaemia. (99m)Tc-MIBI bone marrow scintigraphy can identify the MDR1 and MRP1 phenotype, but not LRP, in patients with acute leukaemia.

Prognostic values of lung resistance protein (LRP) and P53 in patients with multiple myeloma (MM)

8113 Background: This study was undertaken to assess the significance of lung-resistance related protein (LRP) expression and p53 mutations in plasma cells from untreated multiple myeloma (MM) patients and to determine whether LRP expression and p53 deletions was associated with a poor response and survival in patients treated with a conventional dose of melphalan. Methods: We have studied LRP expression by immunocytochemistry and p53 deletions by interphase fluorescence in situ hybridization (FISH) with a DNA probe specific for the p53 locus at 17p13 in bone marrow plasma cells from 38 untreated patients with MM received conventional oral dose melphalan (0.25 mg/kg, day 1 to 4) combined with prednisone (MP). We also studied their association with both response to chemotherapy and survival of the patients. Results: By FISH, deletions of p53, were detected in 31.5% of patients and LRP was found positive in 36.8%. Patients with a p53 deletion were predominantly at stage III (p53 deletion in 83.4% of stage III patients vs. 8.3% of patients at stages I and II respectively; P = 0.04). Both p53 deletion and LRP expression were correlated with other laboratory and clinical parameters. The overall response rate of all of the evaluable patients was 63.2%. The response rate was 79.2% for patients without LRP expression but only 35.7% for patients with LRP expression (P = 0.01). Among the 12 patients with a p53 deletion by FISH, 25% responded compared with 75% of patients without p53 deletion (P = 0.001). With the exception of LRP expression and p53 deletions, there was no other prognostic variable sharing any correlation with response. The median survival of LRP-positive patients was 11 months (95%-Cl: 9 to 24), whereas the median survival duration of LRP negative patients was not reached (Cl: 26 to 82; P &lt; .002; hazard ratio [HR] = 2.9 (1.4–5.7). Patients with and without p53 deletions had significantly different overall survival times (median 13.9 months, 95%-CI: 8 to 26 and median not reached, CI: 24 to84, respectively; P &lt; .0001; hazard ratio [HR] = 2.6). Conclusions: For patients with MM who were treated with conventional-dose chemotherapy, LRP expression and p53 deletions provides prognostically relevant information in addition to that provided by standard prognostic factors. No significant financial relationships to disclose.

The roles of four multi-drug resistance proteins in hepatocellular carcinoma multidrug resistance

The roles of multi-drug resistance protein 1 (MDR1), multi-drug resistance related protein 1 (MRP1), lung resistance protein (LRP) and breast cancer resistance protein (BCRP) in the multi-drug resistance (MDR) of hepatocellular carcinoma (HCC) were studied. By exposing HepG2 cell line to progressively increased concentrations of adriamycin (ADM), HepG2 multi-drug resistant subline (HepG2/ADM) was induced. The MDR index of HepG2/ADM was detected by using MTT. The expressions of the four MDR proteins in the three cell lines (L02, HepG2, HepG2/ADM) were investigated at mRNA and protein levels by real-time RT-PCR and Western blot respectively. Our results showed that when the ADM concentration was under 100 microg/L, HepG2 could easily be induced to be drug-resistant. The IC(50) of the HepG2/ADM to ADM was 282 times that of HepG2. The expression of MDR1 and BCRP mRNA in HepG2/ADM cells were 400 and 9 times that of HepG2 cells respectively while there was no difference in the mRNA expressions of MRP1 and LRP. There was no difference between HepG2 and L02 cells in the mRNA expressions of the four genes. At the protein level, the expressions of MDR1, BCRP and LRP but MRP1 in HepG2/ADM were significantly higher than those of HepG2 and L02. Between HepG2 and L02, there was no difference in the expressions of four genes at the protein level. HepG2/ADM is a good model for the study of MDR. The four genes are probably the normally expressed gene in liver. The expressions of MDR1 and BCRP could be up-regulated by anti-cancer agents in vitro. The MDR of HCC was mainly due to the up-regulation of MDR1 and BCRP but MRP1 and LRP. These findings suggest they may serve as targets for the reversal of MDR of HCC.

Relationship between expression of apoptosis-related genes and multidrug resistance genes in lung cancer tissues and their clinical significance

Multidrug resistance (MDR) of lung cancer is a complex procedure involved in multiple genes and multiple pathways. Besides multidrug resistance genes, there is close relationship between expression of apoptosis-related genes and MDR in lung cancer. The aim of this study is to explore the relationship among the expression of apoptosis-related genes (p53, Bcl-2) and clinicopathological characteristics, and their correlation with multidrug resistance genes such as lung resistance protein (LRP), P-glycoprotein (P-gp), glutathione S-transferase π (GST-π), topoisomerase II (Topo II) and multidrug-resistance-associated protein (MRP) in lung cancer. The expression of P53, Bcl-2, LRP, P-gp, GST-π, Topo II and MRP was detected in 68 lung cancer patients (Bcl-2 for 51 patients) with immunohistochemical staining (Envision method). The positive rate of P53 and Bcl-2 was 75.0% and 33.3% respectively. There was significant difference in P53 expression between non-small cell lung cancer and small cell lung cancer (P=0.001) and among various grades of cell differentiation (P=0.003). There was also significant difference in Bcl-2 expression between squamous cell carcinoma and adenocarcinoma (P=0.002). There was no relationship between the expression of P53 and Bcl-2 (P > 0.05). Spearman analysis showed that there was a positive correlation between the expression of P53 and P-gp (P=0.002), and between P53 and GST-π (P=0.017), and the coexpression rate was 70.6% and 47.1% respectively. There was no correlation between the expression of Bcl-2 and five multidrug resistance factors (P > 0.05). The expression of apoptosis-related gene mutant p53 is significantly related to multidrug resistance factors P-gp and GST-π. It is important to detect both apoptosis-related genes and various multidrug resistance genes.

Expression of Proteins Associated With Multidrug Resistance to Chemotherapy in Lung Cancer

OBJECTIVE: Membrane transporters are proteins that play a crucial role in resistance to chemotherapy. The aim of this study was to assess the influence of membrane transporter protein expression on chemotherapeutic response. MATERIAL AND METHODS: One hundred and forty seven samples of tumor tissue were collected from 143 patients; 35 samples were obtained by bronchoscopy and 112 were surgical specimens. A total of 101 samples from 99 patients were adequate for study. Cryopreserved samples were subjected to immunohistochemical analysis to detect 3 proteins associated with multidrug resistance: P-glycoprotein (Pgp), multidrugresistance‐associated protein 1 (MRP1), and lung resistance protein (LRP). RESULTS: In 16 cases none of the proteins were expressed. A single protein was expressed in 32 (3 Pgp, 11 MRP1, and 18 LRP); 2 in 34 cases (24 Pgp and LRP; 5 MRP1 and Pgp; 5 MRP1 and LRP); and all 3 in 17 cases. No significant relationship was found between age and the expression of Pgp (P=.74), MRP1 (P=.95), or LRP (P=.26). Nor were there significant differences in number (P=.72) or type of coexpressed proteins (P=.39) by sex, by tumor stage (number, P=.55; type, P=.21), or by tumor grade (number, P=.59; type, P=.51). There was a highly significant trend toward coexpression of Pgp and LRP (P<.01) but not of Pgp and MRP1 (P=.18) or MRP1 and LRP (P=.26). MRP1 was expressed less often in adenocarcinoma. LRP was expressed less often in squamous cell carcinoma than in adenocarcinoma and undifferentiated large cell carcinoma. Coexpression of Pgp, MRP1, and LRP was observed most often in squamous cell carcinoma. CONCLUSIONS: Proteins associated with multidrug resistance are commonly expressed in lung cancer. Of the 3 proteins studied, LRP was the one most often found. Coexpression of more than 1 of the proteins was found in a considerable percentage of patients. Pgp was mainly found to be coexpressed with LRP. Pgp expression and the number of coexpressed proteins seemed to have a negative impact on response to chemotherapy.

The clinical significance of P-glycoprotein, lung resistance protein and multidrug resistance related protein expressions in infiltrating breast carcinoma tissues

Our purpose was to explore clinical significance of three kinds of drug resistance related proteins, including P-glycoprotein (P-gp), lung resistance protein (LRP), multidrug resistance related protein (MRP) expressions in infiltrating breast carcinoma tissues. Flow cytometry was used to analyze the expression of drug resistance related proteins in carcinoma tissues and corresponding para-carcinoma tissues from 68 primary infiltrating breast carcinoma patients. The relative fluorescence intensity (RFI) expressed by median (M) of P-gp, LRP and MRP in breast carcinoma tissues were 0.58, 0.51and 0.56 respectively. In corresponding para-carcinoma tissues, their expression level were 0.26, 0.33 and 0.30. Their difference were obvious (P < 0.05). There were not notable differences of drug resistance related protein expressions in different ages, different tumor sizes, different pathological types, different clinical stages, estrogen receptor or progestin receptor negative and positive patients (P > 0.05). The expressions of P-gp and MRP in lymph node metastasis positive patients were 0.61and 0.69, in lymph node metastasis negative patients they were 0.54 and 0.45. There were no notable differences of P-gp and MRP expression in lymph node metastasis negative and positive patients. The expression of LRP (M = 1.49) was higher in lymph node metastasis positive patients than that in negative patients (M = 0.50, P < 0.05). The correlation analysis showed that there was positive correlation between the expression of LRP and MRP in breast carcinoma tissues (P < 0.05). The clinical significance of three kinds of drug resistance related protein expressions had differences in infiltrating breast carcinoma tissues. The expression of LRP had related with lymph node metastasis status and had positive correlation with MRP expression. It can become a target in forecasting breast carcinoma prognosis.

Expression of Multidrug Resistance 1, Lung Resistance Protein and Breast Cancer Resistance Protein Genes in Chronic Lymphocytic and Chronic Myelogeneous Leukemia.

One of the major problems in the treatment of leukemia is the development of drug resistance to chemotherapeutic agents, which is already present at diagnosis or after chemotherapy as a minimal residual disease. The resistance may be originated from genetic or epigenetic mutations during prior growth of the leukemic clone. In this study, the expressions of three multidrug resistance (MDR) genes were investigated. Expression levels of multidrug resistance resistance gene 1 (MDR1), breast cancer resistance protein (BCRP) gene, and lung resistance protein (LRP) gene expression levels were determined in peripheral blood samples from 16 cases of chronic lymphocytic leukemia (CLL) and from 23 cases of chronic myelogeneous leukemia (CML) using RT-PCR. The expression of each of these genes was then expressed as a ratio in relation to β2-microglobulin gene expression in densitometric measurements. MDR1, BCRP and LRP expression levels was detected in 56,3%, 18,8% and 50% of CLL patients, respectively, with no difference for stage or response to the treatment. Four out of 16 (25%) CLL patients expressed none of these genes. The other 25% CLL patients expressed all of these genes. MDR1, BCRP and LRP expression was detected in 47,8%, 39,1% and 30,4% of CML patients, respectively, with no difference for progression or response to imatinib mesylate. Eight out of 23 (34,8%) CML patients expressed none of these genes. Four out of 23 (17,4%) CML patients expressed all of these genes, and two out of whom rapidly progressed to acute leukemia and unresponsive to the treatment. In conclusion, MDR and LRP overexpression seems to be a frequent event in CLL and CML patients; however no conclusion can be drawn on their prognostic role and response to the treatment.

The association of increased lung resistance protein expression with acquired etoposide resistance in human H460 lung cancer cell lines

Chemoresistance remains the major obstacle to successful therapy of cancer. In order to understand the mechanism of multidrug resistance (MDR) that is frequently observed in lung cancer patients, here we studied the contribution of MDR-related proteins by establishing lung cancer cell lines with acquired resistance against etoposide. We found that human H460 lung cancer cells responded to etoposide more sensitively than A549 cells. Among MDR-related proteins, the expression of p-glycoprotein (Pgp) and lung resistance protein (LRP) were much higher in A549 cells compared with that in H460 cells. When we established H460-R1 and -R2 cell lines by progressive exposure of H460 cells to increasing doses of etoposide, the response against etoposide as well as doxorubicin was greatly reduced in R1 and R2 cells, suggesting MDR induction. Induction of MDR was not accompanied by a decrease in the intracellular accumulation of etoposide and the expression of MDR-related proteins that function as drug efflux pumps such as Pgp and MRP1 was not changed. We found that the acquired resistance paralleled an increased expression of LRP in H460 cells. Taken together, our data suggest the implicative role of LRP in mediating MDR in lung cancer.