Cisplatin-resistant Lung Cancer Cell Line Research Articles

Novel Platinum(IV) complexes intervene oxaliplatin resistance in colon cancer via inducing ferroptosis and apoptosis

Platinum-based chemotherapeutics are widely used for cancer treatment but are frequently limited because of dosage-dependent side effects and drug resistance. To attenuate these drawbacks, a series of novel platinum(IV) prodrugs (15a–18c) were synthesized and evaluated for anti-cancer activity. Among them, 17a demonstrated superior anti-proliferative activity compared with oxaliplatin (OXA) in the cisplatin-resistant lung cancer cell line A549/CDDP and OXA-resistant colon cancer cell line HCT-116/OXA but showed a lower cytotoxic effect toward human normal cell lines HUVEC and L02. Mechanistic investigations suggested that 17a efficiently enhanced intracellular platinum accumulation, induced DNA damage, disturbed the homeostasis of intracellular reactive oxygen molecules and mitochondrial membrane potential, and thereby activated the mitochondrion-dependent apoptosis pathway. Moreover, 17a significantly induced ferroptosis in HCT-116/OXA via triggering the accumulation of lipid peroxides, disrupting iron homeostasis, and inhibiting solute carrier family 7 member 11 and glutathione peroxidase 4 axial pathway transduction by inhibiting the expression of the phosphorylated signal transducer and activator of transcription 3 and nuclear factor erythroid 2‐related factor 2. Moreover, 17a exerted remarkable in vivo antitumor efficacy in the HCT-116/OXA xenograft models but showed attenuated toxicity. These results indicated that these novel platinum(IV) complexes provided an alternative strategy to develop novel platinum-based antineoplastic agents for cancer treatment.

Inhibitory Effect and Mechanism of Ursolic Acid on Cisplatin-Induced Resistance and Stemness in Human Lung Cancer A549 Cells.

The survival rate of lung cancer patients remains low largely due to chemotherapy resistance during treatment, and cancer stem cells (CSCs) may hold the key to targeting this resistance. Cisplatin is a chemotherapy drug commonly used in cancer treatment, yet the mechanisms of intrinsic cisplatin resistance have not yet been determined because lung CSCs are hard to identify. In this paper, we proposed a mechanism relating to the function of ursolic acid (UA), a new drug, in reversing the cisplatin resistance of lung cancer cells regulated by CSCs. Human lung cancer cell line A549 was selected as the model cell and treated to become a cisplatin-resistant lung cancer cell line (A549-CisR), which was less sensitive to cisplatin and showed an enhanced capability of tumor sphere formation. Furthermore, in the A549-CisR cell line expression, levels of pluripotent stem cell transcription factors Oct-4, Sox-2, and c-Myc were increased, and activation of the Jak2/Stat3 signaling pathway was promoted. When UA was applied to the cisplatin-resistant cells, levels of the pluripotent stem cell transcription factors were restrained by the inhibition of the Jak2/Stat3 signaling pathway, which reduced the enrichment of tumor stem cells, and in turn, reversed cisplatin resistance in lung cancer cells. Hence, as a potential antitumor drug, UA may be able to inhibit the enrichment of the lung CSC population by inhibiting the activation of the Jak2-Stat3 pathway and preventing the resistance of lung cancer cells to cisplatin.

Ferroptosis as a Potential Cell Death Mechanism Against Cisplatin-Resistant Lung Cancer Cell Line.

Purpose: Drug resistance is a challenging issue in cancer chemotherapy. Cell death induction is one of the main strategies to overcome chemotherapy resistance. Notably, ferroptosis has been considered a critical cell death mechanism in recent years. Accordingly, in this study, the different cell death strategies focused on ferroptosis have been utilized to overcome cisplatin resistance in an in vitro lung cancer model. Methods: The physiological functions of Akt1 and GPX4, as critical targets for ferroptosis and apoptosis induction, were suppressed by siRNA or antagonistic agents in resistant A549 cells. Afterward, the interventions' impacts on cell viability and reactive oxygen species (ROS) amount were analyzed by flow cytometry. Moreover, the alteration in the relevant gene and protein expression levels were quantified using Real-time PCR and western blot methods. Results: The result showed that the treatment with Akt1 siRNA reversed the cisplatin resistance in the A549 cell line through the induction of apoptosis. Likewise, the combination treatment of the GPX4 siRNA or FIN56 as ferroptosis inducers alongside cisplatin elevated ROS's cellular level, reduced the cellular antioxidant genes level and increased the cisplatin cytotoxic effect. Conclusion: In conclusion, our study indicated that ferroptosis induction can be considered a promising cell death strategy in cisplatin-resistant cancer cells.

LncRNA XIST Contributes to Cisplatin Resistance of Lung Cancer Cells by Promoting Cellular Glycolysis through Sponging miR-101-3p

Background: Non-small-cell lung carcinoma is one of the most frequently diagnosed cancers. Cisplatin (CDDP) is a currently applied standard anticancer agent for advanced lung cancers. Although effectively clinical response was achieved initially, a large fraction of lung cancer patients developed cisplatin resistance. Therefore, understanding the molecular mechanisms of chemoresistance is crucial for anti-lung cancer therapy. Long non-coding RNA (lncRNA)-X-inactive-specific transcript (XIST) has been reported to be positively associated with multiple cancers. Currently, the precise role and mechanism of XIST in cisplatin resistance of lung cancer have not been elucidated. Methods: The expression levels of miR-101-3p and lncRNA XIST were detected by qRT-PCR. Cisplatin-resistant lung cancer cell line was established by selecting the survival cells under gradually increased cisplatin treatments. The cell proliferation was detected by MTT assay, and the cellular glucose metabolism rate was evaluated by Seahorse metabolic flux analysis and glucose uptake and lactate product assays. Glycolysis-related protein expression levels were detected by Western blot. Dual luciferase reporter was constructed to determine the lncRNA-miRNA interaction. Results: Here, we report XIST is significantly upregulated in lung cancer tissues compared with normal lung tissues. In addition, cisplatin-resistant lung cancer cells displayed remarkably elevated XIST expression. We demonstrated that miR-101-3p functioned as a tumor suppressor in lung cancer and sensitized lung cancer cells to cisplatin. Bioinformatics analysis predicted miR-101-3p could be a potential target of XIST through direct binding with it as a competing endogenous RNA, which was further validated from lung tumor tissues and cell lines by luciferase assay. Intriguingly, XIST significantly promoted cellular glycolysis rate of lung cancer cells. The extracellular acidification rate, glucose uptake, and lactate product were elevated by XIST overexpression. On the contrary, miR-101-3p effectively suppressed glycolysis rate. Finally, we demonstrated silencing XIST significantly recovered miR-101-3p expression and downregulated expression of glycolysis key enzymes, a phenotype could be further overridden by miR-101-3p inhibition. Conclusions: This study reveals a new molecular mechanism for the lncRNA-XIST-promoted cisplatin resistance via sponging miR-101-3p, leading to de-repression of cellular glycolysis. Moreover, these findings warrant further in vivo investigations to study XIST as a potential target to overcome cisplatin resistance.

The Synthetic Capsaicin‐analog Arvanil sensitizes Cisplatin‐Resistant Human Lung Cancer Cells to the pro‐apoptotic activity of Irinotecan

Cisplatin-based combination therapy is the standard of care for the treatment of human lung cancer. Initially, cisplatin shows excellent therapeutic response but the tumor inevitably relapses (within a year) and this relapsed tumor is resistant to cisplatin. A few human lung cancers do not respond to cisplatin-based first-line chemotherapy. These patients are said to have platinum-refractory lung tumors. Patients with platinum resistant or refractory disease have very limited options, as the only standard chemotherapy with an FDA-approved drug, irinotecan has an objective response rate of approximately 3% and little or no survival benefit. Therefore, agents which improve the therapeutic response (of human lung cancers) towards irinotecan may be useful for the treatment of cisplatin-resistant human lung cancer. The nutritional compound capsaicin sensitized cisplatin-resistant H69-CPR human small cell lung cancer (SCLC) cells towards irinotecan-induced apoptosis. Arvanil is a synthetic capsaicin-analog which displays enhanced growth-suppressive activity in human SCLC. The present study aims to investigate the combinatorial apoptotic activity of arvanil and irinotecan in cisplatin-resistant lung cancer. Caspase-3 activity assays reveal that the combination of irinotecan and arvanil displayed greater apoptotic activity in H69-CPR human cisplatin-resistant SCLC cells than the drugs used alone. These experiments were repeated in a second cisplatin-resistant lung cancer cell line PC9-CDDP and similar results were obtained. Chou-Talalay isobologram analysis showed the interaction between irinotecan and arvanil is synergistic in H69-CPR and PC9-CDDP cells. The combination of arvanil/irinotecan showed a greater synergistic pro-apoptotic activity than the combination of capsaicin/irinotecan. in H69-CPR and PC9-CDDP cells. The pro-apoptotic activity of arvanil/irinotecan was mediated elevation of intracellular calcium and required the calpain pathway. Taken together, our findings pave the way for the discovery of novel combination therapies for the therapy of cisplatin-resistant human lung cancer.

Structure and biological properties of mixed-ligand Cu(II) Schiff base complexes as potential anticancer agents

We synthesized two mixed-ligand Cu(II) complexes containing different aroylhydrazone ligands and a pyridine co-ligand, namely, [Cu(L1)(Py)] (C1) and [Cu(L2)(Py)(Br)] (C2) (L1 = (E)-2-hydroxy-N′-((2-hydroxynaphthalen-1-yl)methylene)benzohydrazide, Py = pyridine, L2 = (E)-2-hydroxy-N′-(phenyl(pyridin-2-yl)methylene)benzohydrazide), and assessed their chemical and biological properties to understand their marked activity. C2 showed better anticancer activity than C1 in various human cancer cell lines, including the cisplatin-resistant lung cancer cell line A549cisR. Both Cu(II) complexes, especially C2, displayed promising anti-metastatic activity against HepG2 cells. Spectroscopic titration and agarose gel electrophoresis experiments indicated that C2 exhibited binding affinity toward calf-thymus DNA and efficient pBR322 DNA-cleaving ability. Further mechanistic studies showed that C2 effectively induced DNA damage and thus led to cell cycle arrest at the G2/M phase, and also stimulated mitochondrial dysfunction mediated by reactive oxygen species and caspase-dependent apoptosis.

Upregulation of Coxsackie Adenovirus Receptor Sensitizes Cisplatin-Resistant Lung Cancer Cells to CRAd-Induced Inhibition.

Objective. Conditionally replicating adenoviruses (CRAds) have been proven potent oncolytic viruses in previous studies. They selectively replicate in the tumor cells because of incorporated survivin promoter and ultimately lead to their killing with minimal side effects on normal tissue. Chemotherapy with cisplatin is commonly employed for treating tumors, but its cytotoxic effects and development of resistance remained major concerns to be dealt with. The aim of this study was to explore the anticancer potential of survivin regulated CRAd alone or in combination with cisplatin in the A549 lung cancer cell line and cisplatin-resistant lung cancer cell line, A549-DDPR.Methods. CRAd was genetically engineered in our laboratory by removing its E1B region and adding survivin promoter to control its replication. A549, H292, and H661 lung cancer cell lines were procured from the CAS-China. The anti-tumor effectiveness of combined treatment (cisplatin plus CRAd) was evaluated in vitro through MTS assays and in vivo through mouse model experimentation. RT- PCR was used to assess MDR gene and mRNA expression of coxsackie adenoviral receptor (CAR).Results. Results of in vitro studies established that A549 lung cancer cells were highly sensitive to cisplatin showing dose-dependent inhibition. The resistant cells of A549-DDPR exhibited very less sensitivity to cisplatin but were infected with CRAd more efficiently as compared to A549. A549-DDPR cells exhibited higher expression of MDR gene and CAR in the RT-PCR analysis. The nearly similar rise in the CAR expression was seen when lung cancer cell lines received cisplatin in combined treatment (cisplatin plus CRAd). Combined anti-cancer therapy (cisplatin plus oncolytic virus) proved more efficient than monotherapy in the killing of cancer cells. Results of in vivo experiments recapitulated nearly similar tumor inhibition activities.Conclusion. This study highlighted the significant role of survivin in gene therapy as it has the potential to render CRAd more tumor specific. It also establishes that higher CAR expression plays a vital role in the success of adenovirus-based therapies. Furthermore, a careful combination of chemotherapy drugs and oncolytic viruses can culminate in significant therapeutic achievements against cancer.

Reversal of platinum drug resistance by the histone deacetylase inhibitor belinostat

ObjectivesTo investigate and elucidate the mechanism for the potentiation of cisplatin anticancer activity by belinostat in platinum (Pt)-resistant lung cancer cells. Materials and methodsCombination of cisplatin and belinostat was investigated in two pairs of parental and cisplatin-resistant non-small cell lung cancer (NSCLC) cell lines. The Pt-resistant cell models exhibited overexpression of the efflux transporter ABCC2 and enhanced DNA repair capacity. Cellular accumulation of cisplatin and extent of DNA platination were measured by inductively coupled plasma optical emission spectrometer. Expression of Pt transporters and DNA repair gene were determined by quantitative real-time PCR. Inhibition of ABCC2 transport activity was examined by flow cytometric assay. Regulation of ABCC2 at the promoter level was studied by chromatin immunoprecipitation assay. Results and conclusionIn Pt-resistant lung cancer cells, belinostat apparently circumvent the resistance through inhibition of both ABCC2 and DNA repair-mediated mechanisms. The combination of belinostat and cisplatin were found to display synergistic cytotoxic effect in cisplatin-resistant lung cancer cell lines when the two drugs were added concomitantly or when belinostat was given before cisplatin. Upon the concomitant administration of belinostat, cellular accumulation of cisplatin and formation of DNA-Pt adducts were found to be increased whereas expression levels of the efflux transporter ABCC2 and the DNA repair gene ERCC1 were inhibited in Pt-resistant cells. Belinostat-mediated downregulation of ABCC2 was associated with an increase association of a transcriptional repressor (negative cofactor 2) but reduced association of a transcriptional activator (TFIIB) to the ABCC2 promoter. The data advocates the use of belinostat as a novel drug resistance reversal agent for use in combination cancer chemotherapeutic regimens.

Sodium/iodide symporter gene transfection increases radionuclide uptake in human cisplatin-resistant lung cancer cells.

The sodium/iodide symporter (NIS) is involved in iodide uptake and has been used for the diagnosis and treatment of thyroid cancer. Transfection of the NIS gene in A549 human lung cancer cells can induce radioactive iodine ((131)I) and radioactive technetium ((99m)Tc) uptake. The aim of the present study was to assess the role of NIS in (99m)Tc and (131)I uptake by the A549/DDP human cisplatin-resistant lung cancer cell line. To do so, recombinant adenovirus, adenovirus-enhanced green fluorescent protein-human NIS (Ad-eGFP-hNIS) and Ad-eGFP-rat NIS (Ad-eGFP-rNIS) vectors were established. These vectors were transfected into A549/DDP cells and xenograft tumors in nude mice. Assessment of (99m)Tc and (131)I uptake was performed. Results showed that the transfection efficiency of Ad-eGFP-hNIS and Ad-eGFP-rNIS in A549/DDP cells was at least 90 % in all experiments, and that the uptake ability of (99m)Tc and (131)I was highly enhanced (14-18 folds for (99m)Tc, and 12-16 folds for (131)I). However, the radionuclide concentration in transfected NIS genes' A549/DDP cells reached a plateau within 30-60 min, indicating that NIS transport led rapidly to (99m)Tc and (131)I saturation in cells. In xenograft tumor models, uptake of (99m)TcO4 (-) was obviously higher in the hNIS and rNIS groups compared with controls. In conclusion, these results support the hypothesis that A549/DDP cells can effectively uptake (99m)Tc and (131)I when transfected with the hNIS and rNIS gene. The rNIS or hNIS gene could be used as an effective method for the effective delivery of radioactive products to specific tissues for imagery and/or treatment.

Abstract B03: Cisplatin-resistant cells possess collateral sensitivity to folate antimetabolites

Abstract Cisplatin is widely used as a first-line chemotherapeutic agent for lung cancers. Although effective initially, lung cancer cells eventually acquire resistance to cisplatin, causing tumor recurrence. Understanding mechanisms that govern cisplatin resistance is expected to improve therapeutic efficacy in lung cancer patients. Although various studies using cisplatin-resistant cell lines have revealed possible mechanisms of resistance, the applicability of these mechanisms in a clinical setting are debatable. One possible reason for this discrepancy may be the use of cell line models which are exposed to unnaturally high doses of cisplatin to yield cells with a resistant phenotype. These cell lines may not be representative of naturally arising cisplatin-resistant cells in tumors that are treated according to a clinically established dose and schedule. Therefore, to improve the experimental model, we have established two new cisplatin-resistant lung cancer cell lines through intermittent low dose challenges that mimic a clinical treatment schedule (one pulse/month for up to six cycles). The resistant cell lines resulting from this procedure demonstrate improved clonogenic potential and sphere-forming properties, suggesting an increase in the population of tumor-initiating cells. Interestingly, via testing with several different anti-cancer drugs, we found that these resistant cells are more sensitive to the antifolate Pemetrexed, in comparison to their parental cells. To conclude, our study suggests that sequential administration of antifolates might be useful in the treatment of lung cancers that have acquired cisplatin resistance. Citation Format: Shih-Shin Chang, Hirohito Yamaguchi, Mien-Chie Hung. Cisplatin-resistant cells possess collateral sensitivity to folate antimetabolites. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Drug Sensitivity and Resistance: Improving Cancer Therapy; Jun 18-21, 2014; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(4 Suppl): Abstract nr B03.

Effect and mechanism of Src tyrosine kinase inhibitor sunitinib on the drug-resistance reversal of human A549/DDP cisplatin-resistant lung cancer cell line.

The development of tumor cell drug resistance is the primary reason for treatment failure in lung cancer chemotherapy. Therefore, overcoming multidrug resistance is currently an urgent issue to be addressed in lung cancer treatment. Sunitinib is a tyrosine kinase inhibitor with confirmed inhibitory effects on tumor growth and metastasis; however, the effects of sunitinib and mechanisms of action in lung cancer multidrug resistance are yet to be determined. The present study was designed to examine the effects of sunitinib and the mechanisms underlying lung cancer multidrug resistance. It was observed that sunitinib was able to improve the sensitivity of A549/DDP lung cancer cells to cisplatin, enhance tumor apoptosis, arrest the cell cycle in G0/G1 phase, upregulate intracellular Rh-123 content, downregulate the expression of P-glycoprotein, multidrug resistance protein 1, multidrug resistance-associated protein 1, lung resistance protein, glutathione-S-transferase, ERCC1, survivin and Bcl-2 in tumor cells, phosphorylation of AKT and extracellular signal-regulated kinase (ERK), glutathione activity, and transcriptional activity of nuclear factor-κB, Twist, Snail and AP-1. The results demonstrated that sunitinib was able to reverse the multidrug resistance of A549/DDP lung cancer cells, which was possibly associated with the downregulation of multidrug resistance-associated gene expression and the inhibition of AKT and ERK phosphorylation.

Novel platinum(ii) compounds with O,S bidentate ligands: synthesis, characterization, antiproliferative properties and biomolecular interactions

Cisplatin and its analogues are first-line chemotherapeutic agents for the treatment of numerous human cancers. A major inconvenience in their clinical use is their strong tendency to link to sulfur compounds, especially in kidney, ultimately leading to severe nephrotoxicity. To overcome this drawback we prepared a variety of platinum complexes with sulfur ligands and analyzed their biological profiles. Here, a series of six platinum(II) compounds bearing a conserved O,S binding moiety have been synthesized and characterized as experimental anticancer agents. The six compounds differ in the nature of the O,S bidentate β-hydroxydithiocinnamic alkyl ester ligand where both the substituents on the aromatic ring and the length of the alkyl chain may be varied. The two remaining coordination positions at the square-planar platinum(II) center are occupied by a chloride ion and a DMSO molecule. These novel platinum compounds showed an acceptable solubility profile in mixed DMSO-buffer solutions and an appreciable stability at physiological pH as judged from analysis of their time-course UV-visible absorption spectra. Their anti-proliferative and pro-apoptotic activities were tested against the cisplatin-resistant lung cancer cell line A549. Assays revealed significant effects of the sample drugs at low concentrations (in the μmolar range); initial structure-activity-relationships are proposed. The activity of the apoptosis-promoting protein caspase 3/7 was determined; results proved that these novel platinum compounds, under the chosen experimental conditions, preferentially induce apoptosis over necrosis. Reactions with the model proteins cytochrome c, lysozyme and albumin were studied by ESI MS and ICP-OES to gain preliminary mechanistic information. The tested compounds turned out to metalate the mentioned proteins to a large extent. In view of the obtained results these novel platinum complexes qualify themselves as promising cytotoxic agents and merit, in our opinion, a deeper pharmacological evaluation as prospective anticancer agents.

Targeting cisplatin-resistant human tumor cells with metabolic inhibitors

Although cisplatin is the drug of choice in treating lung cancer patients, relapse and resistance is a common drawback to its clinical effectiveness. Based on cisplatin's reported ability to interfere with numerous cellular components, including mitochondria, we probed alterations in metabolism in cisplatin-resistant tumor cell lines to reveal targets for overcoming this important form of resistance. Cisplatin-resistant lung and ovarian cancer cell lines were used to evaluate the efficacy of metabolic inhibitors for selectively targeting cisplatin-resistant cells under varying oxygen conditions. Three cisplatin-resistant cancer cell lines expressed lower HKII protein when compared to the respective cisplatin-sensitive cancer cell lines from which they were derived. Under anaerobic and hypoxic conditions, treatment with the glycolytic inhibitors 2-deoxyglucose (2-DG) and 2-fluorodeoxyglucose (2-FDG) correlated with increased cytotoxicity and more pronounced decreases in lactate production in cisplatin-resistant cells, indicating a greater blockage of glycolysis. Knockdown of HKI or HKII with siRNA in the parental lung cancer cell lines led to increased 2-FDG-induced cell death under anaerobic conditions. Under normal oxygen conditions, blockage of either fatty acid oxidation or deprivation of glutamine resulted in cell death in cisplatin-resistant lung cancer cell lines. Altered hexokinase levels in cisplatin-resistant cancer cell lines leads to increased sensitivity to glycolytic inhibition under anaerobic conditions, whereas under normoxic conditions, blockage of either fatty acid oxidation or deprivation of glutamine leads to cell death. These findings may be clinically applicable when considering cisplatin resistance.

1148 RETICULOCALBIN-1 DOWN-REGULATION AS A POSSIBLE PREDICTOR OF CISPLATIN RESISTANCE IN UROTHELIAL CANCER

You have accessJournal of UrologyBladder Cancer: Basic Research III1 Apr 20101148 RETICULOCALBIN-1 DOWN-REGULATION AS A POSSIBLE PREDICTOR OF CISPLATIN RESISTANCE IN UROTHELIAL CANCER Masaaki Tachibana, Yoshio Ohno, Masahiko Kuroda, Ayako Tanaka, Kenji Shimodaira, Jun Nakashima, Takashi Hirano, and Norihiko Ikeda Masaaki TachibanaMasaaki Tachibana More articles by this author , Yoshio OhnoYoshio Ohno More articles by this author , Masahiko KurodaMasahiko Kuroda More articles by this author , Ayako TanakaAyako Tanaka More articles by this author , Kenji ShimodairaKenji Shimodaira More articles by this author , Jun NakashimaJun Nakashima More articles by this author , Takashi HiranoTakashi Hirano More articles by this author , and Norihiko IkedaNorihiko Ikeda More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2010.02.647AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Cisplatin is a main chemotherapeutic agent for urothelial cancer. Urothelial cancer patients treated with cisplatin-based chemotherapy often develop cisplatin resistance and, consequently, cancer recurrence. Therefore, elucidation of the mechanisms underlying cisplatin-resistance is crucial for efficient cancer chemotherapy. Proteomic analysis of cisplatin-resistant lung cancer cell lines identified reticulocalbin-1 as one of the proteins associated with cisplatin resistance. The purpose of this study is to evaluate significance of reticulocalbin-1 in urothelial cancer. METHODS Cisplatin-resistant sublines were established from the urothelial cancer cell lines KU-1, KU-7, and KU-19-19 by repeated subcultures with increasing cisplatin concentrations. Cell cycle analysis was performed by flow cytometry, and cisplatin cytotoxicity was determined with the Alamar Blue cytotoxicity assay. Reticulocalbin-1 expression was analyzed by real-time reverse transcriptase PCR and western blot. Surgically resected urothelial cancer specimens were immunohistochemically analyzed for reticulocalbin-1 to determine its association with response to cisplatin-based chemotherapy. Reticulocalbin-1 immunostaining was determined by the percentage of reticulocalbin-1-positive cells: weak staining, ≤25% of the tumor cells were positive for reticulocalbin-1; moderate, ≤50%; strong, >90%. RESULTS Cell growth inhibition was 2.5-fold greater in cisplatin-resistant sublines than in the parental cell lines. The S-phase fraction showed a significant increase. Reticulocalbin-1 was down-regulated in all three cisplatin-resistant cell lines as compared with their parent cell lines on both mRNA and protein levels. In immunohistochemical analysis, reticulocalbin-1 was expressed in normal urothelial epithelium. Fifteen tumors were strongly positive for reticulocalbin-1; 18, moderately positive; 20, weakly positive. Seventy-five percent (15/20) of patients with weak positive primary cancer did not respond to the chemotherapy. CONCLUSIONS Reticulocalbin-1 expression may be a marker for response to cisplatin-based chemotherapy in urothelial cancer. Tokyo, Japan© 2010 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 183Issue 4SApril 2010Page: e444 Advertisement Copyright & Permissions© 2010 by American Urological Association Education and Research, Inc.MetricsAuthor Information Masaaki Tachibana More articles by this author Yoshio Ohno More articles by this author Masahiko Kuroda More articles by this author Ayako Tanaka More articles by this author Kenji Shimodaira More articles by this author Jun Nakashima More articles by this author Takashi Hirano More articles by this author Norihiko Ikeda More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Non-cross resistance of ZD0473 in acquired cisplatin-resistant lung cancer cell lines

ZD0473 is a new generation platinum agent that, in preclinical studies, shows evidence of an extended spectrum of anti-tumor activity and overcomes platinum resistance mechanisms. The drug contains a bulky methylpyridine ligand at its platinum center, which is responsible for its ability to overcome platinum resistance. We examined the growth inhibitory effects of ZD0473 in human lung cancer cell lines resistant to cisplatin in vitro. Four cisplatin resistant human lung cancer cell lines (PC-14/CDDP, SBC-3/CDDP, PC-9/CDDP, H69/CDDP) showed the expected resistance to cisplatin but were non-cross, or much less, resistant to ZD0473, as determined by an MTT assay. A reduction in the intracellular accumulation of cisplatin, but not of ZD0473, was observed in the PC-14/CDDP cells compared with the levels in PC-14 parental cells. The reduction in cisplatin accumulation is considered a major mechanism of the acquired cisplatin resistance in PC-14/CDDP cells. Therefore, the increase in platinum accumulation is considered a possible mechanism underlying the activity of ZD0473 in cisplatin-resistant cells. Glutathione-mediated resistance to cisplatin was also overcome by ZD0473 in PC-14/CDDP cells. In addition, we showed that the intraperitoneal administration of ZD0473 at its maximum tolerable dose in mice produced a marked in vivo antitumor activity against cisplatin-resistant PC-14/CDDP tumors. These results suggest that ZD0473 may be a potent agent in human lung cancer cells with multifactorial cisplatin resistance.