Search

Kinesin family member C1 (KIFC1) is a minus end-directed motor protein that plays an essential role in centrosome clustering. Previously, we reported that KIFC1 is involved in cancer progression in prostate cancer (PCa). We designed this study to assess the involvement of KIFC1 in docetaxel (DTX) resistance in PCa and examined the effect of KIFC1 on DTX resistance. We also analyzed the possible role of a KIFC1 inhibitor (CW069) in PCa. We used DTX-resistant PCa cell lines in DU145 and C4-2 cells to analyze the effect of KIFC1 on DTX resistance in PCa. Western blotting showed that KIFC1 expression was higher in the DTX-resistant cell lines than in the parental cell lines. Downregulation of KIFC1 re-sensitized the DTX-resistant cell lines to DTX treatment. CW069 treatment suppressed cell viability in both parental and DTX-resistant cell lines. DTX alone had little effect on cell viability in the DTX-resistant cells. However, the combination of DTX and CW069 significantly reduced cell viability in the DTX-resistant cells, indicating that CW069 re-sensitized the DTX-resistant cell lines to DTX treatment. These results suggest that a combination of CW069 and DTX could be a potential strategy to overcome DTX resistance.

Bone metastasis is a major cause of prostate cancer (PCa) morbidity and mortality. Despite some success in transiently controlling clinical symptoms with docetaxel-based therapy, PCa patients become docetaxel-resistant and inevitably progress with no cure. We synthesized an acyl-tyrosine bisphosphonate amide derivative, BKM1644, with the intent of targeting bone metastatic PCa and enhancing docetaxel's efficacy. BKM1644 exhibits potent anti-cancer activity in the NCI-60 panel and effectively inhibits the proliferation of metastatic, castration-resistant PCa (mCRPC) cells, with IC50 ranging between 2.1 μM and 6.3 μM. Significantly, BKM1644 sensitizes mCRPC cells to docetaxel treatment. Mice with pre-established C4-2 tumors in the tibia show a marked decrease in serum prostate-specific antigen (control: 173.72 ± 37.52 ng/ml, combined treatment: 64.45 ± 22.19 ng/ml; p < 0.0001) and much improved bone architecture after treatment with the combined regimen. Mechanistic studies found that docetaxel temporarily but significantly increases survivin, an anti-apoptotic protein whose overexpression has been correlated with PCa bone metastasis and therapeutic resistance. Intriguingly, BKM1644 effectively inhibits survivin expression, which may antagonize docetaxel-induced survivin in bone metastatic PCa cells. Signal transducer and activator of transcription 3 (Stat3) may be involved in the suppression of survivin transcription by BKM1644, as confirmed by a survivin reporter assay. Collectively, these data indicate that BKM1644 could be a promising small-molecule agent to improve docetaxel efficacy and retard the bone metastatic growth of PCa.

Prostate cancer is the most commonly diagnosed and the second most deadly cancer in American men. Despite dramatic initial responses to androgen deprivation therapy (ADT), the disease inevitably progresses to castration-resistant prostate cancer (CRPC), frequently driven by reactivation of the androgen receptor (AR). CRPC remains incurable: current treatment options offer only modest survival benefit and resistance can occur rapidly. Docetaxel remains the standard first line treatment for patients with metastatic CRPC, however, nearly all CRPC patients become refractory due to drug resistance. Interestingly, when docetaxel is deployed with ADT in metastatic hormone-sensitive prostate cancer (mHSPC), survival is improved significantly more than for CRPC. Since AR is frequently reactivated in CRPC, we hypothesized that altered AR signaling influences docetaxel sensitivity in CRPC. Docetaxel binds to microtubules, disrupting microtubule dynamics and activating the mitotic checkpoint pathway, a complex mechanism that maintains mitotic fidelity and prevents chromosome instability. In an analysis of primary prostate and metastatic tumors, we observe differential copy number and expression of several mitotic checkpoint-regulating genes, suggesting reprogramming of the mitotic checkpoint in metastatic CRPC. Furthermore, our in vitro studies demonstrate a novel link between AR activation and mitotic checkpoint signaling. In hormone-sensitive LNCAP cells, AR activation (by addition of androgen) attenuates mitotic checkpoint activation in response to docetaxel, leading to mitotic slippage and resistance to docetaxel. Cell-cycle analysis under these conditions demonstrates loss of G2/M arrest, decreased apoptosis, and an increased tetraploid cell population. In addition, the AR-activated LNCAP cells show significantly fewer mitotic errors (i.e. lagging chromosomes) and an increased number of multi-nucleated cells in response to docetaxel compared to non-hormone treated cells. Importantly, analysis of CRPC cell lines C4-2 and 22Rv1 demonstrate results concordant with the hormone-treated LNCAP cells, suggesting AR signaling can drive mitotic progression to escape cell death. Finally, we determined that microtubule stabilization is critical for AR-mediated checkpoint inhibition and identified several kinase targets that force mitotic arrest and sensitize cells to docetaxel. Our results reveal that targeting key kinases that regulate mitotic checkpoint activation is a novel therapeutic strategy to overcome docetaxel resistance and improve outcomes for patients with lethal prostate cancer. Citation Format: Amanda Pilling, Clara Hwang. Androgen receptor signaling dysregulates the mitotic checkpoint to mediate docetaxel resistance in castration-resistant prostate cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4100.

Background Docetaxel is first-line chemotherapy for castration-resistant prostate cancer (CRPC), but most patients acquire docetaxel resistance. CD44 has been shown to be involved in drug resistance of cancers including prostate cancer. We hypothesized that CD44 in serum exosomes could be a diagnostic marker for docetaxel resistance in CRPC patients. In this study, we examined CD44 protein and mRNA expression in cell lysates and exosomes isolated from prostate cancer cells, evaluated the effect of CD44v8-10 knockdown on docetaxel sensitivity and measured CD44 mRNA copy numbers contained in serum exosomes in prostate cancer patients. Materials and methods Docetaxel-sensitive PC-3 prostate cancer cells and docetaxel-resistant PC-3R cells established previously from parental PC-3 cells were used. CD44v8-10 knockdown was performed by siRNA transfection. Blood was collected from 50 docetaxel-naïve and 10 docetaxel-resistant patients and 15 control males. CD44 protein expression was evaluated by Western blotting. CD44 mRNA expression was measured by RT-digital PCR. Results The levels of CD44v8-10 protein and mRNA in cell lysates and exosomes were higher in PC-3R cells than in PC-3 cells. CD44v8-10 knockdown significantly increased docetaxel sensitivity of PC-3R cells. The CD44v8-10 mRNA copy numbers in serum exosomes were higher in docetaxel-resistant patients than in docetaxel-naïve patients and control males (median 46, 12 and 17 copies/mL serum, respectively, P = 0.032). In contrast, the serum exosomal mRNA copy numbers of CD44 standard isoform (CD44s) were not different among 3 groups (median 25, 14 and 13 copies/mL serum, respectively, P = 0.150). Conclusions CD44v8-10 may be involved in docetaxel resistance in prostate cancer and serum exosomal CD44v8-10 mRNA could be a diagnostic marker for docetaxel-resistant CRPC., Cell biology; Molecular biology; Cancer research; Chemotherapy; Urology; Castration-resistant prostate cancer, CD44, Docetaxel resistance, Exosomes, Diagnostic marker

Patients with metastatic castration-resistant prostate cancer (mCRPC) develop resistance to conventional therapies including docetaxel (DTX). Identifying molecular pathways underlying DTX resistance is critical for developing novel combinatorial therapies to prevent or reverse this resistance. To identify transcriptomic signatures associated with acquisition of chemoresistance we profiled gene expression in DTX-sensitive and -resistant mCRPC cells using RNA sequencing (RNA-seq). PC3 and DU145 cells were selected for DTX resistance and this phenotype was validated by immunoblotting using DTX resistance markers (e.g. clusterin, ABCB1/P-gp, and LEDGF/p75). Overlapping genes differentially regulated in the DTX-sensitive and -resistant cells were ranked by Gene Set Enrichment Analysis (GSEA) and validated to correlate transcript with protein expression. GSEA revealed that genes associated with cancer stem cells (CSC) (e.g., NES, TSPAN8, DPPP, DNAJC12, and MYC) were highly ranked and comprised 70% of the top 25 genes differentially upregulated in the DTX-resistant cells. Established markers of epithelial-to-mesenchymal transition (EMT) and CSCs were used to evaluate the stemness of adherent DTX-resistant cells (2D cultures) and tumorspheres (3D cultures). Increased formation and frequency of cells expressing CSC markers were detected in DTX-resistant cells. DU145-DR cells showed a 2-fold increase in tumorsphere formation and increased DTX resistance compared to DU145-DR 2D cultures. These results demonstrate the induction of a transcriptomic program associated with stemness in mCRPC cells selected for DTX resistance, and strengthen the emerging body of evidence implicating CSCs in this process. In addition, they provide additional candidate genes and molecular pathways for potential therapeutic targeting to overcome DTX resistance.

Background: Both taxanes, docetaxel and cabazitaxel, are effective treatments for metastatic castration-resistant prostate cancer (mCRPC). However, resistance to taxanes is common. Our objective was to investigate mechanisms of taxane resistance in prostate cancer. Methods: Two docetaxel-resistant patient-derived xenografts (PDXs) of CRPC were established (PC339-DOC and PC346C-DOC) in male athymic nude mice by frequent intraperitoneal administrations of docetaxel. Next-generation sequencing was performed on PDX tissue pre- and post-docetaxel resistance and gene expression profiles were compared. [14C]-docetaxel and [14C]-cabazitaxel uptake assays in vitro and cytotoxicity assays were performed to validate direct involvement of transporter genes in taxane sensitivity. Results: Organic anion-transporting polypeptide (SLCO1B3), an influx transporter of docetaxel, was significantly downregulated in PC346C-DOC tumours. In accordance with this finding, intratumoural concentrations of docetaxel and cabazitaxel were significantly decreased in PC346C-DOC as compared with levels in chemotherapy-naive PC346C tumours. In addition, silencing of SLCO1B3 in chemo-naive PC346C resulted in a two-fold decrease in intracellular concentrations of both taxanes. Overexpression of SLCO1B3 showed higher sensitivity to docetaxel and cabazitaxel. Conclusions: The SLCO1B3 determines intracellular concentrations of docetaxel and cabazitaxel and consequently influences taxane efficacy. Loss of the drug transporter SLCO1B3 may drive taxane resistance in prostate cancer.

Background This study investigates the docetaxel-resistant mechanism and explores the effect of tea polyphenols (TP) on autophagy and its related mechanism in human castration-resistant prostate cancer (CRPC) cell lines PC3 and DU145. Methods Immunofluorescence assay and annexin V-FITC/PI double staining flow cytometry were used to analyze the apoptosis and autophagy of PC3 and DU145 cells. The expression of autophagy-related proteins was detected by western bolt. Results Docetaxel could induce autophagy and apoptosis, together with the expression increase in p-JNK, p-Bcl-2 and Beclin1. The level of autophagy was remarkably decreased, but apoptosis was increased after combining with TP. In addition, the expression of p-mTOR was increased after combining with TP. Conclusion Docetaxel induces protective autophagy in CRPC cells by JNK pathway activation and then Bcl-2 phosphorylation and Beclin1 dissociation. TP activates mTOR pathway, which ultimately inhibits docetaxel-induced autophagy and improves therapeutic efficacy of docetaxel in CRPC cells.

On the grounds that miRNAs present in the blood of prostate cancer (PCa) patients are released in the growth medium by PCa cells, it is conceivable that PCa cells resistant to docetaxel (DCT) (DCTR) will release miRNAs that may be found in PCa patients under DCT therapy if resistant PCa cells appear. We isolated DCTR clones respectively from 22Rv1 and DU-145 PCa cell lines and performed through next-generation sequencing (NGS) the miRNAs profiles of the released miRNAs. The analysis of the NGS data identified 105 and 1 miRNAs which were differentially released in the growth medium of the 22Rv1/DCTR and DU-145/DCTR clones, respectively. Using additional filters, we selected 12 and 1 miRNA more released by all 22Rv1/DCTR and DU-145/DCTR clones, respectively. Moreover, we showed that 6 of them were more represented in the growth medium of the DCTR cells than the ones of DCT-treated cells. We speculated that they have the pre-requisite to be tested as predictive biomarkers of the DCT resistance in PCa patients under DCT therapy. We propose the utilization of clones resistant to a given drug as in vitro model to identify the differentially released miRNAs, which in perspective could be tested as predictive biomarkers of drug resistance in tumor patients under therapy.

Background Docetaxel based therapy is one of the first line chemotherapeutic agents for the treatment of metastatic castrate-resistant prostate cancer. However, one of the major obstacles in the treatment of these patients is docetaxel-resistance. Defining the mechanisms of resistance so as to inform subsequent treatment options and combinations represents a challenge for clinicians and scientists. Previous work by our group has shown complex changes in pro and anti-apoptotic proteins in the development of resistance to docetaxel. Targeting these changes individually does not significantly impact on the resistant phenotype but understanding the central signalling pathways and transcription factors (TFs) which control these could represent a more appropriate therapeutic targeting approach. Methods Using a number of docetaxel-resistant sublines of PC-3 cells, we have undertaken a transcriptomic analysis by expression microarray using the Affymetrix Human Gene 1.0 ST Array and in conjunction with bioinformatic analyses undertook to predict dysregulated TFs in docetaxel resistant prostate cancer. The clinical significance of this prediction was ascertained by performing immunohistochemical (IHC) analysis of an identified TF (SRF) in the metastatic sites from men who died of advanced CRPC. Investigation of the functional role of SRF was examined by manipulating SRF using SiRNA in a docetaxel-resistant PC-3 cell line model. Results The transcription factors identified include serum response factor (SRF), nuclear factor kappa-B (NFκB), heat shock factor protein 1 (HSF1), testicular receptor 2 & 4 (TR2 &4), vitamin-D and retinoid x receptor (VDR-RXR) and oestrogen-receptor 1 (ESR1), which are predicted to be responsible for the differential gene expression observed in docetaxel-resistance. IHC analysis to quantify nuclear expression of the identified TF SRF correlates with both survival from date of bone metastasis (p = 0.003), survival from androgen independence (p = 0.00002), and overall survival from prostate cancer (p = 0.0044). Functional knockdown of SRF by siRNA demonstrated a reversal of apoptotic resistance to docetaxel treatment in the docetaxel-resistant PC-3 cell line model. Conclusions Our results suggest that SRF could aid in treatment stratification of prostate cancer, and may also represent a therapeutic target in the treatment of men afflicted with advanced prostate cancer. Electronic supplementary material The online version of this article (doi:10.1186/s12885-017-3100-4) contains supplementary material, which is available to authorized users.

Docetaxel is commonly used as an effective chemotherapeutic drug for gastric cancer patients recently. With the increasing emergence of docetaxel resistance nowadays, identification of suitable biomarkers for predicting chemosensitivity to docetaxel may be a key role for improving therapeutic effects for gastric cancer patients. In this study, we investigated the correlation between the expression of transcription factor forkhead box protein M1 (FOXM1) and chemotherapy response to docetaxel in gastric cancer, the possible mechanism for which was further explored. As a result, FOXM1 overexpression was shown to mediate resistance to docetaxel in gastric cancers. It altered microtubule dynamics to protect tumour cells from docetaxel-induced apoptosis. Mechanistic investigations revealed that tubulin-destabilizing protein Stathmin, which mediated docetaxel resistance in FOXM1-silenced gastric cancer cells, is a direct down-stream target of FOXM1, whereas another microtubule dynamics protein mitotic centromere–associated kinesin (MCAK), shown to be related to docetaxel resistance in gastric cancer cells, is not associated with FOXM1 expression significantly. These results were further provided by immunohistochemical analysis, indicating that FOXM1 and Stathmin expression levels were correlated in 103 post-operational gastric cancer specimens. Moreover, when we attenuated FOXM1 expression with FOXM1 inhibitor thiostrepton, docetaxel resistance in gastric cancers was found to be reversed, simultaneously with the down-regulation of FOXM1 and Stathmin. Therefore, FOXM1 can be a useful marker for predicting and monitoring docetaxel response. Through the inhibition of FOXM1, docetaxel resistance can be reversed, and thus FOXM1 could be a new therapeutic target in docetaxel-resistant gastric cancer.

// Veronica Canovas 1 , Yolanda Punal 1 , Valentina Maggio 1 , Enric Redondo 1 , Mercedes Marin 2 , Begona Mellado 2 , Mireia Olivan 1 , Matilde Lleonart 3 , Jacques Planas 1, 4 , Juan Morote 1, 4 and Rosanna Paciucci 1 1 Biomedical Research Group of Urology, Vall d’Hebron Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain 2 Laboratory of Translational Genomics and Targeted Therapeutics in Solid Tumors, August Pi i Sunyer Biomedical Research Institute (IDIBAPS), Medical Oncoloy Department, Hospital Clinic, Barcelona, Spain 3 Biomedical Research in Cancer Stem Cells, Vall d’Hebron Research Institute, Universitat Autonoma de Barcelona, Barcelona, Spain 4 Deparment of Urology, Vall d’Hebron Hospital, Universitat Autonoma de Barcelona, Barcelona, Spain Correspondence to: Rosanna Paciucci, email: rosanna.paciucci@vhir.org Keywords: PTOV1, docetaxel resistance, prostate cancer, metastasis, apoptosis Received: November 09, 2016 Accepted: June 19, 2017 Published: July 22, 2017 ABSTRACT Metastatic prostate cancer is presently incurable. The oncogenic protein PTOV1, first described in prostate cancer, was reported as overexpressed and significantly correlated with poor survival in numerous tumors. Here, we investigated the role of PTOV1 in prostate cancer survival to docetaxel and self-renewal ability. Transduction of PTOV1 in docetaxel-sensitive Du145 and PC3 cells significantly increased cell survival after docetaxel exposure and induced docetaxel-resistance genes expression ( ABCB1, CCNG2 and TUBB2B ). In addition, PTOV1 induced prostatospheres formation and self-renewal genes expression ( ALDH1A1, LIN28A, MYC and NANOG ). In contrast, Du145 and PC3 cells knockdown for PTOV1 significantly accumulated in the G2/M phase, presented a concomitant increased subG1 peak, and cell death by apoptosis. These effects were enhanced in docetaxel-resistant cells. Analyses of tumor datasets show that PTOV1 expression significantly correlated with prostate tumor grade, drug resistance ( CCNG2 ) and self-renewal ( ALDH1A1, MYC ) markers. These genes are concurrently overexpressed in most metastatic lesions. Metastases also show PTOV1 genomic amplification in significant co-occurrence with docetaxel-resistance and self-renewal genes. Our findings identify PTOV1 as a promoter of docetaxel-resistance and self-renewal characteristics for castration resistant prostate cancer. The concomitant increased expression of PTOV1 , ALDH1A1 and CCNG2 in primary tumors, may predict metastasis and bad prognosis.

Docetaxel has been the standard first-line therapy in metastatic castration resistant prostate cancer. The survival benefit is, however, limited by either primary or acquired resistance. In this study, Du145 prostate cancer cells were converted to docetaxel-resistant cells Du145-R and Du145-RB by in vitro culturing. Next generation RNAseq was employed to analyze these cell lines. Forty-two genes were identified to have acquired mutations after the resistance development, of which thirty-four were found to have mutations in published sequencing studies using prostate cancer samples from patients. Fourteen novel and 2 previously known fusion genes were inferred from the RNA-seq data, and 13 of these were validated by RT-PCR and/or re-sequencing. Four in-frame fusion transcripts could be transcribed into fusion proteins in stably transfected HEK293 cells, including MYH9-EIF3D and LDLR-RPL31P11, which were specific identified or up-regulated in the docetaxel resistant DU145 cells. A panel of 615 gene transcripts was identified to have significantly changed expression profile in the docetaxel resistant cells. These transcriptional changes have potential for further study as predictive biomarkers and as targets of docetaxel treatment. Electronic supplementary material The online version of this article (doi:10.1186/s40064-016-3543-0) contains supplementary material, which is available to authorized users.

BACKGROUND Docetaxel is the first line treatment for castration resistant prostate cancer (CRPC). However, docetaxel resistance rapidly develops. Identifying the critical mechanisms giving rise to docetaxel resistance is the major challenge in advanced prostate cancer.

The treatment of metastatic castrate-resistant prostate cancer has been historically challenging, with few therapeutic successes. Docetaxel was the first cytotoxic therapy associated with a survival benefit in castrate-resistant prostate cancer. Toxicity is typical of other cytotoxic agents, with myelosuppression being the dose-limiting toxicity and neurotoxicity also a notable side effect for some patients. Unfortunately, a significant proportion of men with castrate-resistant prostate cancer will not respond to docetaxel-based therapy and all patients will ultimately develop resistance. Because it is an effective therapy, docetaxel is likely to remain an important part of the treatment arsenal against metastatic prostate cancer for the foreseeable future, despite its toxicities and limitations. Overcoming docetaxel resistance has been a challenge since docetaxel was first established as front-line therapy for metastatic castrate-resistant prostate cancer. Recent studies have shown that several new drugs, including cabazitaxel and abiraterone, are effective after docetaxel failure, dramatically changing the therapeutic landscape for these patients. In addition, a greater understanding of the mechanisms underlying docetaxel resistance has led to several new treatment approaches which hold promise for the future. This review will discuss recent therapeutic advances in metastatic castrate-resistant prostate cancer as well as ongoing clinical trials.

Prolonged survival of patients with castration-resistant prostate cancer has been demonstrated following treatment with a combination of docetaxel and prednisone. This combination has, therefore, become the standard first-line chemotherapy for castration-resistant prostate cancer. Median survival, however, does not exceed 20 months and there are currently no approved second-line treatments for patients who progress after docetaxel treatment. The development of effective and safe treatment strategies is urgently required. Several clinical trials are currently evaluating the use of cytotoxic, antiandrogenic and molecular targeting agents. Preclinical studies are identifying the mechanisms responsible for docetaxel resistance and means of enhancing docetaxel activity. The results of these studies will provide the basis for rationally designed therapeutic approaches. This article summarizes the results of recent preclinical and clinical studies and discusses future perspectives.

Notch signaling is implicated in prostate cancer progression and docetaxel resistance. Cui and colleagues describe the additive efficacy and mechanisms of a γ-secretase inhibitor, PF-03084014, and docetaxel in preclinical models of prostate cancer, suggesting the need for further clinical development of Notch pathway modulators in men with metastatic prostate cancer. Clin Cancer Res; 21(20); 4505–7. ©2015 AACR. See related article by Cui et al., p. 4619

260 Background: The addition of docetaxel to standard androgen deprivation therapy (ADT) has been shown to improve the survival of men with metastatic hormone-sensitive prostate cancer (MHSPC) (Sweeney 2015, James 2016). We noticed PSA progression in some of our patients (pts) during docetaxel treatment and reviewed their outcomes. Methods: Men with MHSPC treated with docetaxel were identified from an electronic oncology pharmacy database. Eligible pts were prescribed docetaxel for metastatic adenocarcinoma of the prostate within 120 days of initiation of ADT. Pts with castration-resistant disease (CRPC), other histologies, and those without metastatic disease were excluded. Demographic, clinical, treatment and outcome data were extracted retrospectively from electronic medical records. Results: 31 eligible pts with MHSPC treated with docetaxel between August 2014 and July 2016 were identified. Median age was 65 years (53-83) and 28 (90%) had high-volume disease as defined by Sweeney et al (2015). Nadir PSA levels 6-7 months from ADT initiation were < 0.2, 0.2-4, and > 4 ng/mL in 29.0%, 36.7% and 36.7%, respectively. At median follow up of 85 weeks, 45.2% of pts had progressed to CRPC and 22.6% had died. Median time to CRPC was 59 weeks and median overall survival was 85 weeks. Seven pts with high-volume disease (25%) had PSA progression while receiving docetaxel treatment. The median overall survival of this group was 26 weeks (17 to 106+) and six have died. Three had visceral metastases. Nadir PSA was < 0.2 (1 pt), 0.2-4 (2 pts) and > 4 ng/mL (4 pts). After docetaxel 2 pts received BSC alone and 5 pts had 1st-line CRPC therapy. No response to abiraterone/enzalutamide was seen (3 pts). Two pts who discontinued docetaxel immediately at PSA progression and were switched to alternative chemotherapy survived > 1 year. Conclusions: A subset of men with MHSPC has lethal docetaxel-resistant disease characterized by early PSA rise. It is important to recognize these patients, but it is not clear if standard CRPC therapies are effective. An immediate early switch to alternative chemotherapy may be helpful. Further research to predict early docetaxel resistance, characterize response to current therapies and identify more effective treatment is needed.

BackgroundForkhead box transcription factor 1 (FOXM1) has been reported to overexpress and correlate with pathogenesis in a variety of human malignancies. However, little research has been done to investigate its clinical significance in gastric cancer.MethodsWe examined the expression of FOXM1 in 103 postoperational gastric cancer tissues and 5 gastric cell lines by immunohistochemistry and western blot analysis respectively. Data on clinic-pathological features and relevant prognostic factors in these patients were then analyzed. Moreover, the association of FOXM1 expression and chemosensitivity to docetaxel in gastric cancer cells was further explored.ResultsOur study demonstrated that the level of FOXM1 expression was significantly higher in gastric cancer than in para-cancer tissues (P 0.1). FOXM1 amplification was identified as an independent prognostic factor in gastric cancer (P = 0.001), and its affection is more significant in patients with tumor size larger than 5 cm (P = 0.004), pT3-4 (P = 0.003) or pIII-IV (P = 0.001). Additionally, shown to mediate docetaxel resistance in gastric cancers by our research, FOXM1 was revealed to alter microtubule dynamics in response to the treatment of docetaxel, and the drug resistance could be reversed with FOXM1 inhibitor thiostrepton treatment.ConclusionsFOXM1 can be a useful marker for predicting patients’ prognosis and monitoring docetaxel response, and might be a new therapeutic target in docetaxel resistant gastric cancer.

e16502Background: Enhancing the effectiveness of docetaxel for men with mCRPC is an unmet clinical need. Preclinical studies in our laboratory demonstrated that high dose pantoprazole can prevent o...