MUC1-C regulates lineage plasticity driving progression to neuroendocrine prostate cancer

Neuroendocrine prostate cancer (NEPC) is an aggressive malignancy with no effective targeted therapies. The oncogenic MUC1-C protein is overexpressed in castration-resistant prostate cancer (CRPC) and NEPC, but its specific role is unknown. Here, we demonstrate that upregulation of MUC1-C in androgen-dependent PC cells suppresses androgen receptor (AR) axis signaling and induces the neural BRN2 transcription factor. MUC1-C activates a MYC→BRN2 pathway in association with induction of MYCN, EZH2 and NE differentiation markers (ASCL1, AURKA and SYP) linked to NEPC progression. Moreover, MUC1-C suppresses the p53 pathway, induces the Yamanaka pluripotency factors (OCT4, SOX2, KLF4 and MYC) and drives stemness. Targeting MUC1-C decreases PC self-renewal capacity and tumorigenicity, suggesting a potential therapeutic approach for CRPC and NEPC. In PC tissues, MUC1 expression associates with suppression of AR signaling and increases in BRN2 expression and NEPC score. These results highlight MUC1-C as a master effector of lineage plasticity driving progression to NEPC.

MUC1-C Activates the NuRD Complex to Drive Dedifferentiation of Triple-Negative Breast Cancer Cells

The NuRD chromatin remodeling and deacetylation complex, which includes MTA1, MBD3, CHD4, and HDAC1 among other components, is of importance for development and cancer progression. The oncogenic mucin 1 (MUC1) C-terminal subunit (MUC1-C) protein activates EZH2 and BMI1 in the epigenetic reprogramming of triple-negative breast cancer (TNBC). However, there is no known link between MUC1-C and chromatin remodeling complexes. Here, we showed that MUC1-C binds directly to the MYC HLH-LZ domain and identified a previously unrecognized MUC1-C→MYC pathway that regulates the NuRD complex. MUC1-C/MYC complexes selectively activated the MTA1 and MBD3 genes and posttranscriptionally induced CHD4 expression in basal- but not luminal-type BC cells. In turn, MUC1-C formed complexes with these NuRD components on the ESR1 promoter. Downregulating MUC1-C decreased MTA1/MBD3/CHD4/HDAC1 occupancy and increased H3K27 acetylation on the ESR1 promoter, with induction of ESR1 expression and downstream estrogen response pathways. Targeting MUC1-C and these NuRD components also induced expression of FOXA1, GATA3, and other markers associated with the luminal phenotype. These findings support a model in which MUC1-C activates the NuRD complex to drive dedifferentiation and reprogramming of TNBC cells. SIGNIFICANCE: MUC1-C directly interacts with MYC to activate the NuRD complex, mediating regulation of the estrogen receptor in triple-negative breast cancer cells.

Targeting MUC1-C Inhibits TWIST1 Signaling in Triple-Negative Breast Cancer

The oncogenic MUC1-C protein and the TWIST1 epithelial-mesenchymal transition transcription factor (EMT-TF) are aberrantly expressed in triple-negative breast cancer (TNBC) cells. However, there is no known association between MUC1-C and TWIST1 in TNBC or other cancer cells. Here, we show that MUC1-C activates STAT3, and that MUC1-C and pSTAT3 drive induction of the TWIST1 gene. In turn, MUC1-C binds directly to TWIST1, and MUC1-C/TWIST1 complexes activate MUC1-C expression in an autoinductive circuit. The functional significance of the MUC1-C/TWIST1 circuit is supported by the demonstration that this pathway is sufficient for driving (i) the EMT-TFs, ZEB1 and SNAIL, (ii) multiple genes in the EMT program as determined by RNA-seq, and (iii) the capacity for cell invasion. We also demonstrate that the MUC1-C/TWIST1 circuit drives (i) expression of the stem cell markers SOX2, BMI1, ALDH1, and CD44, (ii) self-renewal capacity, and (iii) tumorigenicity. In concert with these results, we show that MUC1-C and TWIST1 also drive EMT and stemness in association with acquired paclitaxel (PTX) resistance. Of potential therapeutic importance, targeting MUC1-C and thereby TWIST1 reverses the PTX refractory phenotype as evidenced by synergistic activity with PTX against drug-resistant cells. These findings uncover a master role for MUC1-C in driving the induction of TWIST1, EMT, stemness, and drug resistance, and support MUC1-C as a highly attractive target for inhibiting TNBC plasticity and progression.

MUC1-C Integrates Chromatin Remodeling and PARP1 Activity in the DNA Damage Response of Triple-Negative Breast Cancer Cells

The oncogenic MUC1-C protein is overexpressed in triple-negative breast cancer (TNBC) cells and contributes to their epigenetic reprogramming and chemoresistance. Here we show that targeting MUC1-C genetically or pharmacologically with the GO-203 inhibitor, which blocks MUC1-C nuclear localization, induced DNA double-strand breaks and potentiated cisplatin (CDDP)-induced DNA damage and death. MUC1-C regulated nuclear localization of the polycomb group proteins BMI1 and EZH2, which formed complexes with PARP1 during the DNA damage response. Targeting MUC1-C downregulated BMI1-induced H2A ubiquitylation, EZH2-driven H3K27 trimethylation, and activation of PARP1. As a result, treatment with GO-203 synergistically sensitized both mutant and wild-type BRCA1 TNBC cells to the PARP inhibitor olaparib. These findings uncover a role for MUC1-C in the regulation of PARP1 and identify a therapeutic strategy for enhancing the effectiveness of PARP inhibitors against TNBC. SIGNIFICANCE: These findings demonstrate that targeting MUC1-C disrupts epigenetics of the PARP1 complex, inhibits PARP1 activity, and is synergistic with olaparib in TNBC cells.

Usefulness of Implementing Comprehensive Pharmaceutical Care for Metastatic Renal Cell Carcinoma Outpatients Treated with Pazopanib

BACKGROUND

Pazopanib is an effective treatment option for renal cell carcinoma (RCC). However, the therapy is often limited by the appearance of adverse events (AEs), including nausea/vomiting, hepatic impairment, hand-foot syndrome, diarrhea, hypertension and oral mucositis. Early management of AEs is, therefore, extremely important in order to maximize treatment outcomes.

PATIENTS AND METHODS

This non-randomized controlled before-and-after study was carried out to evaluate the effectiveness of our comprehensive pharmaceutical interventions in 37 outpatients receiving pazopanib for RCC (experimental group). Data were compared with those obtained from 13 patients before the start of pharmaceutical intervention (control group).

RESULTS

The incidence rates of grade 2 or more nausea and anorexia were significantly lower in the experimental, than in the control group (3% versus 38% for nausea, respectively, p=0.003; 8% versus 46% for anorexia, respectively, p=0.005). Importantly, non-adherence based on patient self-assessment was not observed with intervention (0% versus 38%, p<0.001). Consequently, the median total dose of pazopanib was increased by the intervention (72,600 versus 18,200 mg, p=0.002). Moreover, the median time to treatment failure was significantly longer with intervention than before (10.2 versus 1.7 months, HR=0.23, 95% CI=0.110-0.499, p<0.001). These findings suggest that our interventions are highly effective for enhancing treatment outcomes.

Impact of inflammatory marker levels one month after the first-line targeted therapy initiation on progression-free survival prediction in patients with metastatic clear cell renal cell carcinoma

Objectives

Progression-free survival of first-line targeted therapy greatly influences the survival of patients with metastatic renal cell carcinoma. We evaluated whether post-treatment inflammatory markers and lactate dehydrogenase levels had impacts on progression-free survival prediction in addition to those of conventional predictors.

Methods

Two hundred and fifteen patients whose tumors were clear cell type and in whom first-line targeted therapies could be continued for >1 month were evaluated. Pretreatment clinical factors, pathological factors and laboratory data 1 month after targeted therapy initiation-including inflammatory markers (neutrophil count, neutrophil-to-lymphocyte ratio and C-reactive protein) and lactate dehydrogenase-were reviewed. To identify progression-free survival predictors, multivariate analyses were done.

Results

The 1-year progression-free survival rate was 47%. Female gender, Karnofsky performance status <80%, time from diagnosis to systemic treatment <12 months, pretreatment C-reactive protein >3.0 mg/dl and post-treatment neutrophil-to-lymphocyte ratio >3.0 were independent predictors for progression-free survival. In contrast, neither C-reactive protein increase nor neutrophil-to-lymphocyte ratio increase after targeted therapy initiation were independent predictors. Pretreatment lactate dehydrogenase, post-treatment lactate dehydrogenase and lactate dehydrogenase decline were not independent predictors. When all patients were stratified by these independent factors into three groups (0 risk vs. 1 or 2 risks vs. 3 or more risks), there were significant differences in progression-free survival rates between the groups (P < 0.0001). Furthermore, there were also significant differences in overall survival rates between the groups (P < 0.0001).

Conclusions

Integration of post-treatment neutrophil-to-lymphocyte ratio value with pretreatment factors may lead to the establishment of effective predictive model for disease progression in patients with metastatic clear cell renal cell carcinoma who received first-line targeted therapies.

PKM2 under hypoxic environment causes resistance to mTOR inhibitor in human castration resistant prostate cancer

The aim of this study was to explore the efficacy of mTOR inhibitor for castration-resistant prostate cancer (CRPC) under hypoxia. Although under normoxia C4-2AT6, it is a CRPC cell line, expressed elevated pAkt, pS6 and Pyruvate kinase M2 (PKM2) accompanied by elevated HIF-1a expression, 5% hypoxic condition further induced expression of these proteins. These results indicate hypoxic environment elevated PI3K/Akt/mTOR pathway in aggressive prostate cancer. However, C4-2AT6 cells treated with mTOR inhibitor under hypoxia less decreased compared to cells treated with the same dose drugs under normoxia. Western blot analysis showed mTOR inhibitor: RAD001 not only inhibited pS6, but also increased the expression of PKM2 in a dose and time dependent manner. Pyruvate kinase acts on glycolysis. PKM2, which is frequently express in tumor cells, is one isoform of pyruvate kinase. PKM2 is reported to act as a transcription factor. In the present study overexpression of PKM2 in C4-2AT6 induced resistance to RAD001 under normoxia. To evaluate the therapeutic effect of targeting PKM2, we inhibited PKM2 in C4-2AT6 under hypoxia using si-PKM2. The number of C4-2AT6 under chronic hypoxia exposed to siPKM2 significantly decreased compared to intact C4-2AT6 under chronic hypoxia. Furthermore, si-PKM2 improved resistance to mTOR inhibitor in C4-2AT6. When examined using clinical samples, high PKM2 expression was correlated with a high Gleason score and poor PSA free survival. These results suggested that up-regulation of PKM2 is one possibility of resistance to mTOR inhibitor in CRPC. And it is possible that PKM2 is a useful therapeutic target of CRPC.

Change of the 5α/5β ratio of urinary steroid metabolites in benign prostatic hyperplasia patients treated with dutasteride

BACKGROUND

The effects of the administration of dutasteride (DUT) on steroid metabolite pathways in BPH patients have not been examined.

METHODS

Urine and blood samples as well as clinical parameters were prospectively collected after the administration of DUT to 60 BPH patients, and after its withdrawal in another set of 25 BPH patients. Urine samples were assessed using gas chromatography/mass spectrometry for the urinary steroid profile (USP), which simultaneously measures 63 steroid metabolites. We examined pharmacological changes in the 5α/5β ratio of urinary metabolites and their relationships with clinical parameters in patients treated with DUT.

RESULTS

The mean urinary androsterone/etiocholanolone (An/Et) ratio in sex-steroid pathways significantly decreased from 1.39 to 0.02 (p < 0.01). Urinary metabolites in other steroid pathways such as 5αTHF/5βTHF in the glucocorticoid pathway and 5αTHB/5βTHB in the mineralocorticoid pathway also significant decreased after the DUT treatment. As compared to baseline level, the mean An/Et ratios in patients with the withdrawal of DUT were 0.7%, 1.4%, 12.6%, and 82.4% at just before, one month, 3 months, and 6 months after the withdrawal of DUT, respectively. All other steroid pathways changed in a similar manner without the aggravation of urinary symptoms. The recovery ratio of An/Et in USP before and 3 months after the withdrawal of DUT correlated with the recovery ratio of serum PSA levels (ρ = 0.61, p < 0.01).

CONCLUSION

Urinary 5α/5β metabolites in all pathways were strongly suppressed after the administration of DUT for one month and the pharmacological effect of DUT prolonged even after withdrawal of DUT.

Skeletal standardized uptake values obtained by quantitative SPECT/CT as an osteoblastic biomarker for the discrimination of active bone metastasis in prostate cancer

Purpose

To investigate the improvement of prognostication of active bone metastatic burden by discriminating bone metastases from degenerative changes in hot foci, using skeletal standardized uptake values (SUVs) by quantitative bone single photon emission tomography/computed tomography (SPECT/CT) in patients with prostate cancer.

Methods

We investigated 170 patients with prostate cancer who underwent skeletal quantitative SPECT/CT using ^99mTc-methylene-diphosphonate (MDP), through conjugate gradient reconstruction with tissue zoning, attenuation, and scatter corrections applied, called as CGZAS reconstruction, in a retrospective cohort study. The maximum, peak, and average SUVs (SUVmax, SUVpeak, and SUVave, respectively) were obtained for visually normal thoracic (T; n = 100) and lumbar (L; n = 140) vertebral bodies as controls, as well as for bone metastases (n = 126) and degenerative changes (n = 114) as hot foci. They were also correlated with age, body-weight, height, biochemistry data, and extent of disease (EOD). Discrimination accuracy of the SUVs for bone metastases in hot foci was evaluated by a patient-based and lesion-based receiver-operator characteristic curve (ROC) analysis.

Results

The skeletal SUVmax was 7.58 ± 2.42 for T, 8.12 ± 12.24 for L, 16.73 ± 6.74 for degenerative changes, and 40.90 ± 33.46 for bone metastases. The SUVs of the bone metastasis group were significantly (p < 0.001) greater than of the other three groups. With disease extent, serum alkaline phosphatase and prostate specific antigen were increased, while SUVs for bone metastases were decreased in EOD grade 4. In ROC analyses for bone metastases by skeletal SUVs demonstrating the diagnostic accuracy of skeletal SUVs for discriminating bone metastasis from degenerative changes in hot foci, area under curves were 0.840, 0.817, and 0.845 in patient-based mode, and 0.932, 0.920, and 0.930 in lesion-based mode.

Conclusions

The skeletal SUVs by ^99mTc-MDP SPECT/CT for active bone metastases were greater than those for degenerative changes in patients with prostate cancer, with a feasible discrimination accuracy in the hot foci. Therefore, skeletal SUVs, especially SUVmax, in quantitative bone SPECT/CT may be helpful indices for the prognostication of bone metastatic burden, improving discrimination of active bone osteoblastic metastases in patients with prostate cancer from frequently coexisting degenerative changes.

High Absolute Monocyte Count Predicts Poor Clinical Outcome in Patients with Castration-Resistant Prostate Cancer Treated with Docetaxel Chemotherapy

BACKGROUND

The association of peripheral monocyte count and prostate cancer progression is not well characterized.

OBJECTIVE

Our aim was to investigate the prognostic value of absolute monocyte count (AMC), which is thought to modulate immune response in the tumor microenvironment, in castration-resistant prostate cancer (CRPC) patients treated with docetaxel chemotherapy.

METHODS

We retrospectively reviewed the medical records of 214 CRPC patients who received docetaxel therapy and were used as the training and validation set. Docetaxel at a dose of 75 mg/m² was administered every 3 or 4 weeks. Clinicopathological factors and laboratory data were collected to assess the prognostic factors for overall survival (OS) and progression-free survival (PFS).

RESULTS

In the training set, the median age was 73.0 years, and the median prostate-specific antigen (PSA) value was 31.7 ng/ml at initial treatment. The median OS and PFS were 23.0 months (range 1.20-84.0) and 11.2 months (range 3.6-78.0), respectively. According to multivariable Cox regression analysis, AMC ≥400/uL, PSA level ≥20 ng/ml, and Hb <10 mg/dL were associated with increased risk of PSA progression [hazard ratio (HR) 2.06, p = 0.005; HR 2.39, p = 0.002; and HR 2.38, p = 0.024, respectively]. Moreover, multivariate analysis for OS indicated that AMC ≥400/uL, pretreatment PSA level ≥20 ng/ml, presence of visceral metastasis, and alkaline phosphatase ≥284 U/L were independent prognostic factors for shortened OS (HR 2.07, p = 0.004; HR 2.18, p = 0.007; HR 2.11, p = 0.011; and HR 1.67, p = 0.048, respectively). According to the validation set, high AMC remained an independent prognostic factor for PFS and OS (HR 2.26, p = 0.001; and HR 3.10, p < 0.001, respectively).

CONCLUSIONS

Elevated monocyte counts were associated with aggressive tumor features and poor survival outcomes of patients with CRPC treated with docetaxel chemotherapy.

External Validation of the MSKCC and IMDC Risk Models in Patients Treated with Targeted Therapy as a First-line and Subsequent Second-line Treatment: A Japanese Multi-institutional Study

BACKGROUND

Two risk models, the Memorial Sloan Kettering Cancer Center (MSKCC) model and the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) model, have been studied in metastatic renal cell carcinoma (mRCC) treated with targeted therapy.

OBJECTIVE

To validate externally the predictive accuracies of the MSKCC and IMDC models for prognosis in mRCC patients treated with first-line and subsequent second-line targeted therapy.

DESIGN, SETTING, AND PARTICIPANTS

A total of 311 patients were assessed retrospectively.

INTERVENTION

All patients underwent targeted therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

Survival outcomes were assessed using Kaplan-Meier analysis. The predictive ability was evaluated using the c-index.

RESULTS AND LIMITATIONS

Regarding to the first-line targeted therapy, the 3-yr overall survival (OS) rates of the MSKCC (p<0.001) and IMDC models (p<0.001) were 76.2% and 77.3%, respectively, in the favorable-risk group; 46.7% and 47.9%, respectively, in the intermediate-risk group; and 13.4% and 15.6%, respectively, in the poor-risk group. The c-indexes were 0.68 for the MSKCC model and 0.69 for the IMDC model in a first-line setting. Regarding the second-line targeted therapy, the 1-yr OS rates of the MSKCC (p<0.001) and IMDC models (p<0.001) were 80.9% and 90.5%, respectively, in the favorable-risk group; 71.4% and 70.6%, respectively, in the intermediate-risk group; and 31.7% and 24.6%, respectively, in the poor-risk group. The c-indexes were 0.66 for the MSKCC model and 0.65 for the IMDC model in the second-line setting. The study is limited by its retrospective nature.

CONCLUSIONS

The results may assist physicians in providing more appropriate patient counseling and imply the need for a future prognostic tool in mRCC treated with targeted therapy.

PATIENT SUMMARY

Both risk models were useful for the risk stratification in metastatic renal cell carcinoma (mRCC) patients treated with first-line and second-line targeted therapy; however, it might be necessary to further update or optimize the models for our Japanese cohort of mRCC patients.

Nicotine Induces Tumor Growth and Chemoresistance through Activation of the PI3K/Akt/mTOR Pathway in Bladder Cancer

Continued smoking is highly associated with not only a higher incidence but also greater risk of tumor recurrence, progression, and acquired chemoresistance of urothelial carcinoma. We investigated whether nicotine affects urothelial carcinoma, and the detailed mechanism by which nicotine could induce tumor growth and any associated chemoresistance. Cell viability was evaluated in the human bladder cancer cell line T24 exposed to nicotine with or without cisplatin (CDDP) and NVP-BEZ235 as a PI3K/mTOR dual inhibitor by the WST-1 assay. Protein expression of the PI3K/Akt/mTOR pathway was investigated by Western blotting or immunohistochemical analysis. The influence of nicotine on tumor growth was also evaluated with or without CDDP and/or NVP-BEZ235 in a subcutaneous bladder tumor model. The result demonstrated that cell proliferation was increased in T24 cells after exposure to nicotine. Phospho-specific Akt (pAkt) and phospho-specific p70 S6 kinase (pS6) were significantly upregulated by nicotine exposure. Tumor growth in vivo was significantly induced by nicotine exposure in accordance with increased pS6 expression. Nicotine attenuated inhibition of T24 cell growth by CDDP and further upregulated pS6 expression in vitro and in vivo. NVP-BZE235 inhibited T24 cell proliferation and pAkt and pS6 expression induced after exposure to nicotine and/or CDDP. In conclusion, nicotine increases tumor growth and induces acquired chemoresistance through activation of the PI3K/Akt/mTOR pathway in bladder cancer.

Limited in vitro efficacy of CYP17A1 inhibition on human castration resistant prostate cancer

Although accumulating evidence indicates high expression of CYP17A1(P45017A1) allows castration resistant prostate cancer (CRPC) to maintain high intratumoral androgen levels, the potential P45017A1 activity has not been characterized yet. The aim of this study was to examine the potential CYP17A1 activity including 17α-hydroxylase and 17,20-lyase activities in human CRPC and the effect of a CYP17A inhibitor. We used three human CRPC cell lines: C4-2 and C4-2AT6 which was established from C4-2 under androgen ablation conditions for 6months, and PC3. To ascertain the potential CYP17A1 activity, we cultured with the steroid precursors: (13)C-[2,3,4]-progesterone (13C-Prog), and analyzed the sequential biosynthesis (13)C-[2,3,4]-17-hydroxyprogesterone (13C-17OHP) and (13)C-[2,3,4]-androstenedione(13C-Adione) by liquid chromatography/mass spectrometry (LC/MS/MS).The C4-2AT6 cells showed significantly higher CYP17A1 expression than C4-2 cells (p<0.001). LC/MS/MS analysis enabled us to detect the 13C-17-OHP and 13C-A-dione in these cell lines. The concentration ratio of 13C-Adione/13C-17OHP (Adione-17OHP ratio), which is thought to reflect the differences between 17-hydroxylase and 17,20-lyase activities, was then determined. The Adione-17OHP ratio in C4-2AT6 cells was significantly higher than that of C4-2 cells (p<0.001). Abiraterone were able to inhibit the CYP17A activities, although abiraterone did not have anti-proliferative effects on C4-2 and C4-2AT6 cells at clinically achievable concentrations of <1000nM in vitro. The present study clearly demonstrates CRPC have the dual activities of CYP17A1 mediated by 17-hydroxylase activity and 17,20-lyase activity. Abiraterone doesn't have an in vitro anti-proliferative efficacy in CRPC cells, suggesting limited efficacy in vitro.

Predictive factors for severe and febrile neutropenia during docetaxel chemotherapy for castration-resistant prostate cancer

BACKGROUND

The aim of this study is to identify factors that increase the occurrence of severe neutropenia (SN) and febrile neutropenia (FN) during docetaxel treatment for castration-resistant prostate cancer (CRPC).

METHODS

We retrospectively reviewed 258 courses during the first three cycles among 95 patients. Docetaxel at a dose of 75 mg/m(2) was administered every 3 or 4 weeks. Patient background, laboratory data, and bone scan results were collected to assess predictive factors for SN and FN. We defined SN as an absolute neutrophil count (ANC) of <500/mm(3) and defined FN as an ANC of <1000/mm(3) with a body temperature of >38.3 °C.

RESULTS

The mean age of the patients was 72.6 ± 6.4 years and the mean prostate-specific antigen was 135.4 ± 290.9 ng/ml. During the first three courses of treatment, SN occurred in 72.6% of patients and FN occurred in 9.5 % of patients. Univariate analysis demonstrated that age ≥ 75 years (p = 0.002), number of comorbidities ≥ 1.2 (p = 0.008 and p = 0.006) and previous external beam radiation therapy (EBRT) (p = 0.001) were predictive factors for the development of SN or FN. In multivariate analysis, significant predictors of SN or FN were age ≥ 75 years (hazard ratio [HR] 5.77; p = 0.004) and previous EBRT (HR 14.5; p = 0.012). According to the subgroup analysis dividing SN and FN separately, multivariate analysis also revealed that age ≥ 75 years and previous EBRT were also significant predictors for developing SN (HR 5.09; p = 0.023, HR 12.7; p = 0.020, respectively) and for developing FN (HR 5.45; p = 0.042, HR 7.72; p = 0.015, respectively).

CONCLUSIONS

Patients aged ≥ 75 years and with a history of localized radiation therapy are at higher risk for significant neutropenic events and require closer surveillance.

Potent increased risk of the initiation of DNA replication in human prostate cancer with the use of 5α-reductase inhibitors

Recent clinical studies have raised the clinically important question of the relationship between dihydrotestosterone (DHT) and prostate cancer (PCa) progression. The significance of DHT or 5α-reductase inhibitors (5ARI) in PCa development and progression has not yet been fully characterized. The aim of this study was to determine whether the initiation of DNA replication was influenced by DHT in PCa. Three cell lines were used. LNCaP: a human PCa cell line that exhibits androgen-dependent proliferation, C4-2: a human PCa cell line that exhibits androgen-independent proliferation, and C4-2AT6: a castration resistant prostate cancer cell line. Two 5ARIs, finasteride and dutasteride, were used. We examined the mRNA expression of the components of pre-replication complex (Pre-RC), CDC6, CDT1, and MCM2-7. DHT induced cell proliferation of LNCaP accompanied by significantly increased CDC6, CDT1, and MCM2-7 expression. In contrast to LNCaP, DHT inhibited cell proliferation in C4-2AT6 cells accompanied by decreased expression of CDC6, CDT1, and MCM2-7. These reverse effects resemble the effects of 5ARIs in Pre-RC. Treatment with finasteride or dutasteride inhibited CDC6 expression in LNCaP, but both 5ARIs induced CDC6 expression in C4-2 and C4-2AT6 cells.These results indicate that DHT showed reversal effects on PCa cell proliferation among prostate cancer cells based on androgen-dependence, accompanied by regulation of the initiation of DNA replication. 5ARIs may modulate the DNA replication system in someaggressive PCa through up-regulation of CDC6 expression.

Dual PI3K/mTOR inhibitor NVP-BEZ235 sensitizes docetaxel in castration resistant prostate cancer

PURPOSE

Effective therapeutic strategies that can achieve long-term improvement in patients with castration resistant prostate cancer are urgently needed. We recently reported that the activated PI3K/Akt/mTOR signaling pathway induced by docetaxel explains resistance to docetaxel in castration resistant prostate cancer. In this study we explored the efficacy of NVP-BEZ235, a dual PI3K and mTORC1/2 inhibitor, for docetaxel resistant castration resistant prostate cancer.

MATERIALS AND METHODS

We used the 2 human castration resistant prostate cancer cell lines C4-2 and C4-2AT6. At our laboratory C4-2AT6 cells were established from C4-2 under androgen ablated treatment for 6 months. We investigated the efficacy of NVP-BEZ235 monotherapy and NVP-BEZ235 combined with docetaxel in vitro and in vivo.

RESULTS

Increased phosphorylated Akt in C4-2AT6 cells was significantly inhibited by NVP-BEZ235 in a dose and time dependent manner. WST cell proliferation assay results in C4-2AT6 cells revealed that combined administration of NVP-BEZ235 and docetaxel had significant, synergistically greater cytotoxicity than NVP-BEZ235 or docetaxel monotherapy. Combined NVP-BEZ235 (40 mg/kg) and docetaxel (4 mg/kg) in vivo in a castrated mouse xenograft model inhibited C4-2AT6 tumor growth to a greater degree than in the monotherapy groups. Also, NVP-BEZ235 showed significant efficacy with docetaxel at a low concentration in vivo, suggesting that NVP-BEZ235 effectively decreased resistance to docetaxel.

CONCLUSIONS

Results suggest that inhibition of the PI3K/Akt/mTOR signaling pathway by NVP-BEZ235 can overcome docetaxel resistance in human castration resistant prostate cancer. Our findings provide a molecular basis for the clinical use of combined administration of NVP-BEZ235 and docetaxel in patients with castration resistant prostate cancer.

Prognostic value of preoperative multiparametric magnetic resonance imaging (MRI) for predicting biochemical recurrence after radical prostatectomy

OBJECTIVE

To evaluate the suitability of preoperative multiparametric magnetic resonance imaging (MRI) positivity as a predictor of biochemical recurrence after radical prostatectomy (RP).

PATIENTS AND METHODS

We reviewed the clinical records of patients who underwent either standard RP or laparoscopic RP between January 2005 and December 2009 at our institution. Patients who received radiotherapy or androgen deprivation therapy before surgery were excluded. A total of 314 patients met the study inclusion criteria. Cox proportional hazard regression models were used for analyses. In accordance with the criteria in the established guidelines, a radiologist scored the probability of the presence of prostate cancer using a five-point scale of diagnostic confidence level. The highest confidence level of any pulse sequence was considered as the evaluation result.

RESULTS

MRI positivity was significantly associated with a high clinical stage (cT ≥ 2; P = 0.039), a high positive biopsy core rate (≥0.2; P < 0.001), a high biopsy Gleason score ([GS] ≥8; P < 0.001) and a high pathological GS (≥8; P = 0.005). Univariate analysis and multivariate analysis showed that MRI positivity was a prognostic indicator in the analysis that included only preoperative variables and also in the analysis including preoperative and pathological variables.

CONCLUSION

Multiparametric MRI positivity can independently predict biochemical recurrence after RP.

Therapeutic enhancement of S-1 with CPT-11 through down-regulation of thymidylate synthase in bladder cancer

Thymidylate synthase (TS), a target enzyme of 5-fluorouracil (5-FU), is significantly associated with prognosis in various cancers. Recently, it has been reported that S-1, a novel 5-FU-based agent has an effect on bladder cancer. However, in cells with high TS level, S-1 did not have significant effects. Therefore, we examined whether down-regulation of TS enhanced effects of S-1 in them. First, we measured TS level in an aggressive bladder cancer cell line, KU-19-19 by enzyme-linked immunosorbent assay (ELISA) and evaluated its sensitivity to 5-FU using a small interfering RNA (siRNA) for TS. Next, we measured TS mRNA after exposure to various agents. Finally, we evaluated enhancement of cytotoxicity of S-1 by CPT-11 (7-ethyl-10-[4-(1-piperidino)-1-piperidino]carbonyloxycamptothecin) which down-regulated TS in in vivo study. The median TS and dihydropyrimidine dehydrogenase (DPD) level was 53.3 ng/mg and 80.3 ng/mg in KU-19-19 cells, respectively. The 5-FU treatment in KU-19-19 cells transfected with siRNA for TS gene (TYMS) inhibited cell growth more significantly than that for nontargeting control. Down-regulation of TS was observed after exposure to SN-38 (7-ethyl-10-hydroxycamptothecin) in a dose-dependent manner. The combination treatment of 5-FU and SN-38 significantly inhibited cell growth, as compared to the single treatment. Meanwhile, in cells transfected with siRNA for TYMS, neither an additive nor a synergistic effect was observed. Also, combined S-1 and CPT-11 dramatically inhibited tumor growth, compared to S-1 or CPT-11 alone in in vivo study. In conclusion, CPT-11 down-regulated TS level and enhanced the effect of S-1. Thus, the combination therapy with S-1 and CPT-11 might be a novel modality for bladder cancer, even with high TS level.

This study confirmed that thymidylate synthase (TS) level in an aggressive human bladder cancer cell line, KU-19-19, was relatively higher than that in other cancer and presented that irinotecan (CPT-11) could down-regulate TS. Finally, the combination therapy with S-1 and CPT-11 resulted in significant tumor growth inhibition through down-regulation of TS in KU-19-19. Thus, combined S-1 and CPT-11 might be a novel treatment in bladder cancer, even with high TS.

Efficacy and safety of docetaxel-based chemotherapy in Japanese men over 80 years old with castration-resistant prostate cancer

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Background: Docetaxel-based chemotherapy is widely used to treat castration-resistant prostate cancer (CRPC). However, its efficacy in elderly males has not yet been fully elucidated. In Japan, the number of elderly CRPC patients continues to increase. Therefore, it is urgently necessary to evaluate the effect of docetaxel-based chemotherapy in elderly Japanese men with CRPC. Methods: Sixty-eight male patients with CRPC who were treated with first-line docetaxel-based chemotherapy in a single institution from 2006 to 2011 were evaluated retrospectively. Results: The median age was 72.4 ± 6.5 years. Ten patients (14.7 %) were ≥ 80 years old (older group), and 58 (85.3 %) were < 80 years old (younger group). All patients received docetaxel at a dose of 75 mg/m2 once every 3 weeks, and prednisolone 10 mg was given every day orally. The prostate-specific antigen (PSA) levels of the older and younger groups before docetaxel-based chemotherapy were 41.2 ± 37.4 ng/ml and 106.5 ± 184.7 ng/ml, respectively (P = 0.273). The PSA doubling times before docetaxel-based chemotherapy were 91.6 ± 92.6 days and 92.5 ± 91.9 days, respectively (P = 0.977). The performance status of the older group was 0 or 1. In the same group, 7 patients (70.0%) achieved a PSA decline of ≥ 30% and 4 patients (40.0%) achieved a PSA decline of ≥ 50%. In the younger group, the PSA decline was ≥ 30% in 37 patients (63.8%) and ≥ 50% in 26 patients (44.8%). The PSA decline rates of ≥ 30% and ≥ 50% were not significantly different between the two groups (p = 0.68 and p = 0.75, respectively). Progression-free survival (PFS) was also not significantly different between the two groups (PFS 5.3 vs. 7.3 months, p = 0.39). The major grade 3–4 toxicities were myelosuppression. Grade 3/4 neutropenia occurred in 80.0% of the older group and 78.0% of the younger group, and Grade 4 neutropenia occurred in 20.0% of the older group and 24.2% of the younger group. There were no significant differences between the two groups (Grade 3/4; p = 0.89, Grade 4; p = 0.79). Conclusions: Docetaxel-based chemotherapy showed a significant effect with a tolerable adverse event rate in elderly Japanese males over 80 years old with castration-resistant prostate cancer.

Disappearance of a major thrombus in the brachiocephalic vein without anticoagulant therapy in a patient with seminoma - a case report

This is the first case report describing brachiocephalic vein thrombosis without compression by a metastatic tumor during chemotherapy for testicular cancer. According to previous reports of testicular cancer patients with a major thrombus, anticoagulant therapy was required to resolve all cases. However, in the present case, a major thrombus in the brachiocephalic vein disappeared without anticoagulant therapy. This 42-year-old man was diagnosed with testicular seminoma and multiple metastases to the para-aortic lymph nodes. After three cycles of cisplatin, etoposide, and bleomycin (PEB) therapy, a major thrombus in the right brachiocephalic vein was recognized on a CT scan. Although no anticoagulant therapy was undertaken, the thrombus in the right brachiocephalic vein was no longer visible on CT after the 4th cycle of PEB therapy.