Lung Resistance Protein Expression Research Articles

A monoclonal antibody against basic fibroblast growth factor attenuates cisplatin resistance in lung cancer by suppressing the epithelial-mesenchymal transition.

Objectives : To investigate the underlying mechanisms of how the basic fibroblast growth factor monoclonal antibody (bFGFmAb) attenuates cisplatin (DDP) resistance in lung cancer using A549 cells and cisplatin-resistant A549 cells (A549/DDP). Methods : Cancer cell proliferation, cell viability, and 50% inhibitory concentration (IC50) of cisplatin were assessed. Transwell assays were utilized to evaluate the invasion activity of tumor cells in response to treatment. Epithelial-to-mesenchymal transition markers and drug resistance proteins were analysed using Western blots. Results: We demonstrate that the bFGFmAb inhibits the proliferation and invasion of both A549 and A549/DDP cells. The bFGFmAb increases cisplatin sensitivity of both A549 and A549/DDP cells as evidenced by an increase in the IC50 of cisplatin in A549 and A549/DDP cells. Furthermore, bFGFmAb significantly increases the expression of E-cadherin, whilst decreasing the expression of N-cadherin and bFGF in both cell lines, thereby showing inhibition of epithelial-to-mesenchymal transition. In addition, we demonstrate that bFGFmAb significantly reduces the expression of the lung resistance protein. Conclusions: Our data suggests that the humanized bFGFmAb is a promising agent to attenuate cisplatin resistance in NSCLC. The underlying mechanism for this effect of bFGFmAb may be associated with the inhibition of epithelial-to-mesenchymal transition and reduced expression of lung resistance protein.

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.

Multidrug resistance affects the prognosis of primary epithelial ovarian cancer.

Multidrug-resistant tumor cells can tolerate different structures, functions and antidrug action mechanisms, therefore, allowing these cells to respond to various structurally unrelated mechanisms of different chemotherapy drugs and to exhibit cross-resistance. The present study aimed to investigate the role of Multi-drug resistance gene (MDR1), Placental glutathione S-transferase-P1 (GSTP1), Lung resistance protein (LRP) and Ras association domain family member 1 (RASSF1A) in primary epithelial ovarian cancer (PEOC). The mRNA (protein) expression levels of MDR1, product P glycoprotein, LRP and GSTP1 were evaluated with reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis in all tissue samples, ovarian cancer cell line A2780 and A2780/DDP. Methylation-specific PCR (MSP) was used to detect RASSF1A gene methylation in all tissue samples. The resistance genes/proteins were either poorly or not expressed in A2780, however were highly expressed in A2780/DDP cell line. The expression of resistance genes/proteins decreased following different concentrations of zebularine-stimulated A2780/DDP. Hypermethylation and low expression of RASSF1A gene were detected in PEOC and A2780/DDP. Subsequent to being exposed to different concentrations of zebularine-stimulated A2780/DDP, the RASSF1A methylation level was decreased, while the unmethylation level was increased. The expression of RASSF1A gene/protein was gradually restored, and the gene/protein expression was enhanced with the increase in drug concentration. Multivariate logistic regression indicated that the expression level of gene LRP and GSTP1 was a risk factor for PEOC prognosis. Furthermore, the expression of LRP and GSTP1 in the negative-group survival curves was higher compared with the positive group. High expression of resistance genes may serve an important role in cancer primary resistance. Low expression caused by hyper-methylation of RASSF1A gene may serve an important role in cancer-acquired resistance in PEOC. The present study suggested that resistant gene expression may be a potential prognostic biomarker.

The CK2 inhibitor CX4945 reverses cisplatin resistance in the A549/DDP human lung adenocarcinoma cell line.

Lung cancer negatively impacts global health, and the incidence of non-small cell lung cancer (NSCLC) is highest among all forms of lung cancer. Chemotherapy failure mainly occurs due to drug resistance; however, the associated molecular mechanism remains unclear. Casein kinase II (CK2), which plays important roles in the occurrence, development and metastasis of many tumours, regulates Wnt signaling by modulating β-catenin expression. In the present study the effects of the CK2 inhibitor, CX4945 on cisplatin [or cis-diamminedichloroplatinum (II); (DDP)]-resistant A549 cells (A549/DDP) were investigated to elucidate the underlying molecular mechanism. A549/DDP cells were divided into four groups (blank control, CX4945, cisplatin and CX4945+cisplatin). Cisplatin resistance was 5.16-fold greater in A549/DDP cells compared with that in A549 cells, with an optimal cisplatin concentration of 5 µg/ml. Moreover, levels of CK2, dishevelled-2 (DVL-2) phosphorylated (p) at Ser143 (p-DVL-2Ser143), and major Wnt-signaling proteins were significantly higher in A549/DDP cells compared with that in A549 cells (P<0.05), with these levels further increased following cisplatin treatment (P<0.05), whereas these levels significantly decreased in A549 cells after cisplatin treatment (P<0.05). Additionally, multidrug-resistance-associated protein 1 and lung resistance protein expression was significantly higher in A549/DDP cells compared with that in A549 cells (P<0.05), with these levels increasing further in A549/DDP (P<0.05) but not A549 cells upon cisplatin treatment (P>0.05). In addition, reduced expression of resistance proteins in A549/DDP cells was accompanied by a decline in the 50% growth inhibition after CX4945 pre-treatment. Furthermore, levels of p-DVL-2Ser143 and major Wnt-signaling proteins decreased significantly after treatment of A549/DDP cells with CX4945+cisplatin, whereas DVL-2 and p-DVL-2Thr224 levels remained unchanged. Additionally, significant elevations in apoptosis rates in the CX4945+cisplatin group relative to the control and cisplatin-only groups, was observed (P<0.001). These results suggested that inhibiting Wnt/β-catenin signaling with CX4945, which attenuates levels of drug-resistance-associated proteins and induces apoptosis, might reverse cisplatin resistance in NSCLC.

Expression of resistance gene and prognosis of chemotherapy in primary epithelial ovarian cancer

The sensitivity of tumor cells to chemotherapy drugs may become attenuated accounts for various reasons. Reduced drug sensitivity may cause the failure of chemotherapy and affect the prognosis of patients with cancer. This study investigates the relationship between the expression levels of lung resistance protein (LRP) and placental glutathione S-transferase-P1 (GSTP1), the resistance of primary epithelial ovarian cancer (PEOC) to chemotherapy, and the prognosis of patients with platinum drug-resistant PEOC.Quantitative PCR (QT-PCR) was used to detect the mRNA level of the resistance genes LRP, GSTP1 in all tissue and cell lines.The expression levels of resistance gene (LRP, GSTP1) in PEOC were the highest, followed by borderline adenoma tissues, and the lowest levels found in benign tumor tissues, the difference of genes expression between different tissues was statistically significant; the difference between the expression rates and relative expression level of drug resistance genes was statistically significant in platinum sensitive group compare with the platinum resistant group. The difference between resistant gene negative-expression and positive-expression of chemotherapy efficiency, disease free survival time, and recurrence time were statistically significant. The resistant genes expression in the PEOC patients of the negative-group survival curves was higher than that in the positive group. With ascites non-cellular component (ANCC) stimulated SKOV3 cells, the cell proliferation inhibition rate (CPIR) increased, and with ANCC stimulated SKOV3/DDP, the expression of LRP and GSTP1 also increased.ANCC may promote the expression of drug resistance genes, and the expression of genes may predict the poorly prognosis of epithelial ovarian cancer.

Expression of multidrug-resistance associated proteins in human retinoblastoma treated by primary enucleation.

To reveal the expression of multidrug-resistance associated proteins: glutathione-S-transferase π (GSTπ), P-glycoprotein (P-gp) and vault protein lung resistance protein (LRP) in retinoblastoma (RB) without any conservative treatment before primary enucleation and to correlate this expression with histopathological tumor features. A total of 42 specimens of RB undergone primary enucleation were selected for the research. Sections from the formalin-fixed, paraffin-embedded specimens were stained with HE and immunohistochemistry to detect the expression of GSTπ, P-gp and LRP. GSTπ was expressed in 39/42 (92.86%) RBs and in 9/9 (100%) well-differentiated RBs. P-gp/GSTπ was found in 30 (71.42%) of 42 RBs. Totally 9 (21.43%) tumors were well differentiated and 33 (78.57%) were poorly differentiated. Totally 15 (35.71%) eyes had optic nerve (ON) tumor invasion, 36 (85.71%) had choroidal tumor invasion, and 14 (33.33%) had simultaneous choroidal and ON invasion. There was no statistically significant relationship between P-gp, GSTπ, LRP positivity and the degree of ocular layer tumor invasion and ON tumor invasion (P>0.05). RB intrinsically expresses GSTπ, P-gp and LRP. GSTπ expression is positive in 100% well-differentiation ones, so in which way it is correlated with differentiation. But the other two proteins expressions are not related to tumor differentiation and to the degree of tumor invasion. GSTπ may be a new target of chemotherapy in RB.

Cisplatin induces expression of drug resistance-related genes through c-jun N-terminal kinase pathway in human lung cancer cells.

Change of multidrug resistance-related genes (e.g., lung resistance protein, LRP) and overexpression of anti-apoptotic genes (Bcl-2, Bcl-Xl, XIAP, Survivin) are responsible for cisplatin resistance. In our study, we investigated the mechanism by which cisplatin induces LRP, Bcl-2, Bcl-xL, XIAP, and Survivin expression in human lung adenocarcinoma A549 cells and human H446 small cell lung cancer cells at mRNA and protein levels. In our study, cell proliferation was assessed with CCK-8 assays, and cell apoptosis was assessed with flow cytometric analysis and Annexin-V/PI staining. qPCR was used to complete RNA experiments. Protein expression was assessed with Western blotting. Cisplatin increased Bcl-2, LRP, and Survivin expression, but decreased Bcl-xL and XIAP expression in a dose-dependent manner. Preincubation with JNK-specific inhibitor, SP600125, significantly inhibited these genes' expression at mRNA and protein levels, enhanced chemosensitivity of lung cancer cells to cisplatin, and promoted cisplatin-induced apoptosis. Our data suggest that the JNK signaling pathway plays an important role in cisplatin resistance. Lung resistance protein (LRP) and anti-apoptotic genes (Bcl-2, Bcl-Xl, XIAP, Survivin) are involved in the process. The results reminded us of a novel therapy target for lung cancer treatment.

Differential expression of breast cancer-resistance protein, lung resistance protein, and multidrug resistance protein 1 in retinas of streptozotocin-induced diabetic mice.

To investigate the altering expression profiles of efflux transporters such as breast cancer-resistance protein (BCRP), lung resistance protein (LRP), and multidrug resistance protein 1 (MDR1) at the inner blood-retinal barrier (BRB) during the development of early diabetic retinopathy (DR) and/or aging in mice. Relative mRNA and protein expression profiles of these three efflux transporters in the retina during the development of early DR and/or aging in mice were examined. The differing expression profiles of Zonula occludens 1 (ZO-1) and vascular endothelial growth factor-A (VEGFA) in the retina as well as the perfusion characterization of fluorescein isothiocyanate (FITC)-dextran and Evans blue were examined to evaluate the integrity of the inner BRB. There were significant alterations in these three efflux transporters' expression profiles in the mRNA and protein levels of the retina during the development of diabetes mellitus and/or aging. The development of early DR was confirmed by the expression profiles of ZO-1 and VEGFA in the retina as well as the compromised integrity of the inner BRB. The expression profiles of some efflux transporters such as BCRP, LRP, and MDR1 in mice retina during diabetic and/or aging conditions are tested, and the attenuated expression of BCRP, LRP, and MDR1 along with the breakdown of the inner BRB is found, which may be linked to the pathogenesis of early DR.

Expression levels of resistant genes affect cervical cancer prognosis.

Tumor cells may develop multidrug resistance (MDR) to various chemotherapy regimens. Such resistance reduces the sensitivity of cells to chemotherapy drugs, leading to the failure of cervical cancer (CC) treatment and disease progression. The present study aimed to investigate the role of MDR1, lung resistance protein (LRP) and placental glutathione S‑transferase π 1 (GSTP1) in CC and MDR, and the prognostic value of these genes. The mRNA expression levels of these resistance‑associated genes were determined in 47 CC and 20 healthy cervical tissue samples. Subsequently, the data was analyzed alongside clinicopathological parameters. The mRNA expression levels of MDR1, LRP and GSTP1 in CC were 0.57±0.32, 0.58±0.29 and 0.44±0.24, respectively, whereas those in healthy cervical tissues were 0.19±0.10, 0.17±0.14 and 0.18±0.10, respectively. Therefore, the expression levels of these genes were significantly greater in CC compared with healthy cervical tissue (P<0.05). mRNA expression levels of MRD1 were increased in the well differentiated group (0.68±0.27) compared with the poorly differentiated group (0.38±0.33; P<0.05). No significant differences were observed between LRP and GSTP1 mRNA expression levels and tumor differentiation or clinical stage of the patients (P>0.05). Multivariate logistic regression indicated that the degree of differentiation and the MDR1 gene expression levels were predictors of CC prognosis (P<0.05). The survival rate of patients in the MDR1‑negative group was significantly greater compared with the MDR1‑positive group (P<0.05). The results of the present study therefore suggested that MDR1 gene expression is a predictor of poor survival in CC.

Synergistic Antitumor Effect of Amorphigenin Combined with Cisplatin in Human Lung Adenocarcinoma A549/DDP Cells

背景与目的Amorphigenin是从紫穗槐属植物的种子中分离提取的鱼藤酮类化合物，研究发现amorphigenin对多种肿瘤细胞具有增殖抑制作用。本研究拟探讨amorphigenin对人肺腺癌耐顺铂细胞株A549/DDP的抗肿瘤作用及其可能的分子机制。方法采用CCK-8法测定A549/DDP细胞的增殖；克隆形成实验测定A549/DDP细胞的克隆形成；流式细胞术检测细胞的凋亡率；Western blot技术检测caspase-3、PARP和LRP蛋白的表达。结果Amorphigenin可抑制A549/DDP细胞的增殖48 h[半数抑制浓度(half maximal inhibitory concentration, IC50)]为(2.19±0.92)μmol/L、抑制克隆形成及诱导细胞凋亡。此外，Amorphigenin与顺铂联合可协同地抑制A549/DDP细胞生长和促进凋亡；降低耐药蛋白LRP蛋白的表达。结论Amorphigenin可抑制A549/DDP细胞增殖和促进细胞凋亡；amorphigenin可能是通过抑制耐药蛋白LRP蛋白表达，进而与顺铂对A549/DDP细胞产生协同抑制作用。

Expression and relationship between hepaCAM protein and multidrug resistance protein in renal carcinoma

Objective To investigate the expression and relationship between hepatocyte cell adhesion molecule (hepaCAM) protein and some multidrug resistance proteins in renal carcinoma tissue. Methods Expressions of hepaCAM, multidrug resistance associated protein (MRP), P-glycoprotein (P-gp), lung resistance protein (LRP), and topoisomerase Ⅱ (TOPO Ⅱ) protein were detected by immunohistochemistry in different areas of human renal cell carcinoma tissues and their relationships were analyzed. Results In the peripheral zone of renal tumor, hepaCAM, MRP, P-gp and LRP protein were showed positive expression. In the central region of the renal tumor, the expressions of hepaCAM, P-gp and LRP were negative or weakly positive, while the expressions of MRP and TOPO Ⅱ protein were positive. The expressions of MRP and TOPO Ⅱ protein in the central region of tumor were stronger than those in the peripheral zone of tumor (31.23±5.67 vs. 23.89±4.56; 45.66±2.34 vs. 5.23±0.66), with statistically significant differences (t=-6.20, P=0.00; t=-100.16, P=0.00). While the expressions of other proteins (hepaCAM, P-gp and LRP) in the central region of tumor were weaker than those in the peripheral zone of tumor (3.21±1.12 vs. 27.25±2.23; 2.34±0.33 vs. 51.23±3.45; 4.22±1.78 vs. 44.23±1.45), with statistically significant differences (t=60.87, P=0.00; t=90.35, P=0.00; t=107.18, P=0.00). Correlation analysis showed that the expression of hepaCAM protein in the central region of renal carcinoma was related with the expression of MRP protein (r=0.94, P=0.01), but it was not related with the expressions of P-gp, LRP and TOPO Ⅱ protein (r=0.22, P=0.44; r=0.14, P=0.80; r=0.34, P=0.07). Conclusion The expression of hepaCAM protein in renal carcinoma may be related to tumor drug-resistance. Key words: Kidney neoplasms; Cell adhesion molecules; Multidrug resistance-associated proteins

Combination of gambogic acid with cisplatin enhances the antitumor effects on cisplatin-resistant lung cancer cells by downregulating MRP2 and LRP expression.

Cisplatin resistance is a main clinical problem of lung cancer therapy. Gambogic acid (GA) could prohibit the proliferation of a variety of human cancer cells. However, the effects of GA on cisplatin-resistant lung cancer are still unclear. The objective of the present study was to find out the antitumor effects of GA on cisplatin-resistant human lung cancer A549/DDP cells and further explore its underlying mechanisms. Cell Counting Kit-8 assay was used to observe the impacts of GA and/or cisplatin on the proliferation of lung cancer cells; flow cytometry was used to detect the effects of GA on cell cycle and apoptosis; Western blot was used to examine the effects of GA on the expression of lung resistance protein (LRP) and multidrug resistance-associated protein 2 (MRP2) protein in A549/DDP cells. Our results showed that GA dose- and time-dependently prohibited the proliferation and induced significant cell apoptosis in A549 and A549/DDP cells. GA also induced G0/G1 arrest in both A549/DDP and A549 cells. Moreover, GA upregulated protein expression level of cleaved caspase-3 and Bax and downregulated protein expression level of pro-caspase-9 and Bcl-2 in time- and dose-dependent way in A549/DDP cells. GA combined with cisplatin enhanced the cells apoptotic rate and reduced the cisplatin resistance index in A549/DDP cells. In addition, GA reduced the MRP2 and LRP protein expression level in A549/DDP cells. GA inhibits the proliferation, induces cell cycle arrest and apoptosis in A549/DDP cells. Combination of GA with cisplatin enhances the antitumor effects on cisplatin-resistant lung cancer cells by downregulating MRP2 and LRP expression.

Prognostic implications of survivin and lung resistance protein in advanced non-small cell lung cancer treated with platinum-based chemotherapy

Platinum-based chemotherapy is the first-line treatment for non-small cell lung cancer (NSCLC), but the chemotherapy often results in the development of chemoresistance. The present study aimed to explore the prognostic implications of survivin and lung resistance protein (LRP) in advanced NSCLC treated with platinum-based chemotherapy. Tumor samples were collected from 61 hospitalized patients with stage IIIB-IV NSCLC that underwent platinum-based chemotherapy. All patient samples were collected in the Oncology Department of the Third Affiliated Hospital of Guangxi Medical University between January 2006 and January 2011. Cytoplasmic survivin and LRP expression were evaluated using immunohistochemistry. The expression of LRP and survivin reached 77% (47/61) and 76% (45/61), respectively. Positive expression of survivin was associated with a lower median progression-free survival (PFS) time (4 vs. 9 months; P=0.038) and a lower median overall survival (OS) time compared with the absence of survivin expression (9 vs. 16 months; P=0.039). Patients with LRP and survivin expression (n=41) demonstrated a median PFS time of 4 months. However, patients with either LRP or survivin expression (n=10) demonstrated a median PFS time of 8 months, which is similar to the median PFS time of the 10 patients with no expression of LRP and survivin (9 months; P=0.022). Either the expression of survivin or the combined expression of LRP and survivin is associated with a poor prognosis in advanced NSCLC treated with platinum-based chemotherapy.

The Expression of Lung Resistance Protein in Saliva: A Novel Prognostic Indicator Protein for Carcinoma of the Breast

ABSTRACTConsidering that saliva is a fluid inundated with proteins, it is possible that solubilized oncogenic proteins may be present in saliva and may be useful in differentiating between healthy and diseased individuals. As a consequence, the purpose of this study was to determine if the solubilized form of LRP was present in stimulated whole saliva and could differentiate between 16 healthy women and 16 women with confirmed Stage I breast cancer. LRP levels were determined using gel electrophoresis and Western blot technology. The results showed LRP at significantly higher concentrations among breast cancer subjects as compared to healthy women.

Clinical significance of the resistance proteins LRP, Pgp, MRP1, MRP3, and MRP5 in epithelial ovarian cancer.

This study aimed to evaluate the correlation between the expressions of lung resistance protein (LRP), P-glycoprotein (Pgp), multidrug resistance-associated protein (MRP)-1, MRP3, and MRP5 and histopathological parameters and clinical outcome, and to determine the predictive and prognostic value of these transport proteins in patients with ovarian cancer. Tumor samples from 111 chemonaive patients with epithelial ovarian cancer who underwent primary surgery from 2006 to 2010 were immunohistochemically stained for LRP, Pgp, MRP1, MRP3, and MRP5 expressions. MRP1 expression was greater among patients with late disease than among patients with early stage ovarian cancer [International Federation of Gynecology and Obstetrics (FIGO) I + II, 71.6% (confidence interval, 60-100); FIGO III + IV, 83.6% (confidence interval, 100-100); P = 0.03]. The histological subtype correlated with the expressions of LRP, Pgp, MRP1, and MRP3. Relapse of disease during the next 24 months occurred more often among patients with higher Pgp and MRP1 than among patients with lower Pgp and MRP1 expressions. FIGO stage, histological type, debulking efficiency, strong Pgp expression, and strong MRP1 expression correlated significantly with shorter progression-free survival (log-rank test, P = 0.001, P = 0.004, P = 0.001, P = 0.051, and P = 0.046, respectively). FIGO stage, histological type, debulking efficiency, and strong MRP1 expression correlated with poor patient survival (log-rank test, P = 0.001, P = 0.042, P = 0.005, and P = 0.018, respectively). Pgp and MRP1 expressions were clinically significant in patients with ovarian cancer. Pgp and MRP1 may be reliable, independent predictive and prognostic factors regarding the clinical outcome of ovarian cancer. MRP3 is less important as a predictive and prognostic factor than MRP1 expression. MRP5 and LRP expressions were not applicable prognostic parameters regarding ovarian cancer.

The Association of Glutathione S-transferase Gene Mutations (including GSTT1 and GSTM1) with the Prognostic Factors and Relapse in Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common malignancy in children. It accounts for one fourth of all childhood cancers and approximately 75% of all childhood leukemias. Some prognostic factors determine the outcome of therapy [e.g. age, sex, initial white blood cell count (WBC), etc.]; however, it is believed that other mechanisms such as glutathione S-transferase (GST) gene mutation, the expression of lung resistance protein (LRP), and multidrug resistance-associated protein (MRP) also plays a role in treatment failure. In this study, GST gene mutations including GSTM1 and GSTT1 were evaluated in patients with leukemia. Thirty newly diagnosed ALL patients younger than 15 years of age participated in the present study. Bone marrow aspiration and biopsy were evaluated for immune phenotyping and DNA was extracted for GST genotyping. All data plus sex, age, initial WBC count, central nervous system (CNS) or testicular involvement, immune phenotype, and outcome (relapse or not) were analyzed statistically. Genotyping showed that 46% were double null, 50% were M1 null and 93.3% were T1 null for GST mutations. There was no statistically significant relationship between GSTT1 and GSTM1 mutations, or between double null status, prognostic factors and relapse (P > .05). So, although the results of GST mutations were consistent, it seems that these mutations are not statistically significant.

Expression and implication of Pgp, MRP, LRP, GST-π in bladder urothelial carcinoma

Objective To evaluate the expression of Pgp,MRP,LRP,GST-π,their co-expression,their clinical relativity and significances in bladder urothelial carcinoma.Methods From February 2005 to November 2010,51 patients (40 males and 11 females) with bladder cancer were recruited.The mean age was 60 years (range from 36 to 83 years).All 51 patients were with bladder urothelial carcinomas.Of whom,11 cases were grade Ⅰ tumors,18 cases were grade Ⅱ tumors and 22 cases were grade Ⅲ tumors.34 cases'were multifocal tumors,17 cases were unifocal tumors.In tumor size.There were 30 cases with tumor greater than 3cm in diameter and the other 21 cases with tumor smaller than 3 cm in diameter.Pglycoprotein (Pgp),Multi-drug resistance related protein (MRP),lung resistance protein (LRP),Glutathione s-transteferase-π (GST-r) of all the ladder urothelial carcinomas were detected by immunohistochemistry SP.The relativity and significances of the 51 cases were analyzed at the same time to find out their clinical-pathological features and relationships.Results The positive expression rates of Pgp,MRP,LRP,GST-π were 70.6％ (36/51),21.6％ (11/51),84.3％ (43/51),92.2％ (47/51),respectively.Pgp protein expression rates were 67.7％ (23/34) and 76.5％ (13/17) in multifocal tumors and unifocal tumors; MRP protein expression rates were 17.7％ (6/34) and 29.4％ (5/7) in multifocal tumors and unifocal tumors; LRP protein expression rates were 85.2％ (29/34) and 88.2％ (15/17) in multifocal tumors and unifocal tumors; GST-r protein expression rates were 88.2％ (30/34) and 100.0％ (17/17)in multifocal tumors and unifocal tumors.Pgp protein expression rates were 57.1％ (12/21) and 46.7％(14/30) in tumors larger than 3cm and tumors smaller than 3cm,respectively; MRP protein expression rates were 19.1％ (4/21) and 23.3％ (7/30) in tumors larger than 3cm and tumors smaller than 3cm;LRP protein expression rates were 81.0％ (17/21) and 86.7％ (26/30) in tumors larger than 3cm and tumors smaller than 3 cm; GST-π protein expression rates were 95.2％ (20/21) and 90.0％ (27/30) in tumors larger than 3 cm and tumors smaller than 3 cm.Pgp protein expression rates were 81.8％ (9/11),61.1％ (11/18) and 72.7％ (16/22) in grade Ⅰ,grade Ⅱ and grade Ⅲ tumors; MRP protein expression rates were 36.4％ (4/11),16.7％ (3/18) and 18.2％ (4/22) in grade Ⅰ,grade Ⅱ and grade Ⅲ tumors; LRP protein expression rates were 100.0％ (11/11),88.9％ (16/18) and 72.7％ (16/22) in grade Ⅰ,grade Ⅱ and grade Ⅲ tumors; GST-π protein expression rates were 100.0％ (11/11),94.4％ (17/18) and 86.4％ (19/22) in grade Ⅰ,grade Ⅱ and grade Ⅲ tumors.LRP protein expression rates were 60.0％ (6/10) and 90.2％ (37/41) in patients of different ages (P ＜ 0.05).GST-π protein expression rates were 95.0％ (38/40) in males and 81.8％ (9/11) in females (P ＜ 0.05).The co-expression rates werePgp+MRP 13.7％ (7/51),Pgp+LRP 58.8％ (30/51),Pgp+GST-π 64.7％ (33/51),MRP+LRP 15.7％ (8/51),MRP+GST-π 15.7 ％ (8/51),LRP+GST-π 82.4％ (42/51),Pgp+MRP + LRP + GST-π 13.7％ (7/51),Pgp + LRP + GST-π 56.9％ (29/51).Significant relationships were detected between Pgp and MRP (r =0.077,P ＜ 0.05),Pgp and GST-π (r =0.097,P ＜ 0.05),MRP and LRP (r =0.065,P ＜0.05),MRP and GST-π (r =0.052,P ＜0.05),LRP and GST-π (r =0.093,P ＜ 0.05).But no statistical significance relationship between Pgp and LRP(r =0.097,P ＞ 0.05)was found.Conclusions The multi-drug resistance in bladder urothelial carcinomas is affected by various multi-drug resistance genes.The expression of LRP is related to patient's age.The expression of GST-π is related to patient's gender.No relationship is established between expression of Pgp,MRP,LRP,GST-π and tumor occurrence frequency,tumor numbers,tumor size,histological grade,clinical-pathological features. Key words: Bladder urothelial carcinoma; Multi-drug resistance associated proteins; Immunohistochemistry

TFPI‐2 Downregulates Multidrug Resistance Protein in 5‐FU‐Resistant Human Hepatocellular Carcinoma BEL‐7402/5‐FU Cells

Tissue factor pathway inhibitor-2 (TFPI-2) is known to induce apoptosis and to suppress tumor metastasis in several types of cancer cells. However, there is little known about its reversal effect on chemoresistant tumor cells. This study investigated the effect of TFPI-2 in 5-fluorouracil (5-FU)-resistant human hepatocellular cancer BEL-7402/5-FU cells in vitro. We constructed TFPI-2 overexpression BEL-7402/5-FU cell lines and explored resistance index (RI) of 5-FU, function of the P-glycoprotein (P-gp) efflux pump, and the mRNA and protein expression of drug resistance gene, including multidrug resistance gene (MDR1), lung-resistance protein (LRP), multidrug resistance-associated protein (MRP1), glutathione-S-transferase-π (GST-π), excision repair cross-complementing gene 1 (ERCC1), and p38 phosphorylation. We found that TFPI-2 improved the RI of 5-FU and inhibited P-gp function. Western blotting and real-time PCR revealed that TFPI-2 also decreased mRNA and protein expression of MDR1, LRP, MRP1, GST-π, and ERCC1, whereas p38 phosphorylation was increased. We considered that TFPI-2 reduces 5-FU resistance in BEL-7402/5-FU cells, and the mechanism appears to involve p38-mediated downregulation of drug resistance gene expression such as MDR1, LRP, MRP1, GST-π, and ERCC1.

Folate Decorated Dual Drug Loaded Nanoparticle: Role of Curcumin in Enhancing Therapeutic Potential of Nutlin-3a by Reversing Multidrug Resistance

Retinoblastoma is the most common intraocular tumor in children. Malfunctioning of many signaling pathways regulating cell survival or apoptosis, make the disease more vulnerable. Notably, resistance to chemotherapy mediated by MRP-1, lung-resistance protein (LRP) is the most challenging aspect to treat this disease. Presently, much attention has been given to the recently developed anticancer drug nutlin-3a because of its non-genotoxic nature and potency to activate tumor suppressor protein p53. However, being a substrate of multidrug resistance protein MRP1 and Pgp its application has become limited. Currently, research has step towards reversing Multi drug resistance (MDR) by using curcumin, however its clinical relevance is restricted by plasma instability and poor bioavailability. In the present investigation we tried to encapsulate nutlin-3a and curcumin in PLGA nanoparticle (NPs) surface functionalized with folate to enhance therapeutic potential of nutlin-3a by modulating MDR. We document that curcumin can inhibit the expression of MRP-1 and LRP gene/protein in a concentration dependent manner in Y79 cells. In vitro cellular cytotoxicity, cell cycle analysis and apoptosis studies were done to compare the effectiveness of native drugs (single or combined) and single or dual drug loaded nanoparticles (unconjugated/folate conjugated). The result demonstrated an augmented therapeutic efficacy of targeted dual drug loaded NPs (Fol-Nut-Cur-NPs) over other formulation. Enhanced expression or down regulation of proapoptotic/antiapoptotic proteins respectively and down-regulation of bcl2 and NFκB gene/protein by Fol-Nut-Cur-NPs substantiate the above findings. This is the first investigation exploring the role of curcumin as MDR modulator to enhance the therapeutic potentiality of nutlin-3a, which may opens new direction for targeting cancer with multidrug resistance phenotype.

The expression and significance of MRP1, LRP, TOPOIIβ, and BCL2 in tongue squamous cell carcinoma

Multiple drug resistance protein 1 (MRP1), lung resistance protein (LRP), topoisomerase IIβ (TOPOIIβ) and B-cell lymphoma 2 (BCL2) are well known in the development of drug resistance in cancer cells. The aim of this study was to evaluate the relationship between them and the clinicopathological features, their expression differences between tumor tissue and experimental drug-resistant model in tongue carcinoma. Multiple drug resistance protein 1, LRP, TOPOIIβ, and BCL2 expression was examined by immunohistochemistry in specimens from radical surgeries of 65 patients with tongue carcinoma. A cisplatin-resistance cell line, SCC-15/cisplatin, was established from a cisplatin-sensitive cell line, SCC-15. A MTT-based method was used to analyze drug potencies. Immunofluorescence was used to detect protein expression in both cell lines. Western blot was used to compare the protein expressions in specimens and SCC-15/cisplatin cells. We found higher expression of MRP1, LRP, and BCL2 and lower expression of TOPOIIβ in tongue carcinoma compared with adjacent non-neoplastic tongue tissues (P < 0.05). In addition, MRP1 and TopoIIβ expression were significantly associated with clinical stage, lymph node metastasis and histologic grade, and LRP was significantly associated with histologic grade in the samples (P < 0.05). Finally, Western blot showed that higher expressions of MRP1, LRP, and BCL2 and lower expression of TopoIIβ were observed in SCC-15/cisplatin cells than in clinical samples. Our results suggest that the high expressions of MRP1, LRP, and BCL2 and low expression of TOPOIIβ in patients with tongue carcinoma indicates that intrinsic drug resistance may exist in tongue carcinoma, and is associated with tumor differentiation and cisplatin resistance in tongue carcinoma.