Longitudinal change in castration-resistant prostate cancer biomarker AST/ALT ratio reflects tumor progression

We investigated whether aspartate transaminase (AST)-to-alanine aminotransferase (ALT) ratio and its change during the course of treatment in castration-resistant prostate cancer (CRPC) patients is associated with tumor condition and lethality. Clinical data from 130 CRPC patients were retrospectively evaluated. AST/ALT ratios at the time of prostate cancer (PC) diagnosis, androgen deprivation therapy (ADT), CRPC diagnosis, and the final follow-up examination after CRPC treatment were calculated for each. The prognostic capabilities of the AST/ALT ratio for overall survival (OS) were analyzed by use of the Kaplan-Meier method and Cox hazard models. The median AST/ALT ratio at PC diagnosis was 1.517 and the optimal value predicting lethality defined by the receiver operating curve was 1.467. The AST/ALT ratio decreased once during ADT and then elevated in a stepwise manner with cancer progression. In surviving patients, the median AST/ALT ratio at the time of PC diagnosis was 1.423, which did not change longitudinally, whereas that in patients later deceased was significantly higher (1.620) and further elevated after CRPC diagnosis. Kaplan-Meier curves indicated significantly worse OS in patients with an AST/ALT ratio ≥ 1.467, which was confirmed by multivariate analysis. These findings indicate AST/ALT ratio as a prognostic biomarker for CRPC with longitudinal changes reflecting tumor progression.

Urine pH and imaging findings of prostate useful predictors of prolonged duration of hematospermia

BACKGROUND

Few investigations regarding hematospermia duration have been reported thus far. The aim of this study was to identify clinical factors associated with the duration of hematospermia.

METHODS

Clinical data of 198 patients with hematospermia treated at Toho University Omori Medical Center from 2007 to 2022 were retrospectively evaluated. To identify independent predictors of hematospermia duration, uni- and multivariate Cox analyses were performed. Receiver operating characteristic analysis, Kaplan-Meier survival curves, and propensity score matching were applied for statistical evaluations.

RESULTS

Multivariate analysis of all 198 patients showed urine pH (UpH) level and any abnormal imaging finding of the prostate to be independent predictors of hematospermia duration. Based on the receiver-operating curve of UpH level for hematospermia improvement, the patients were divided into two groups using a threshold of 6.0 (Low-UpH 5.0-6.0, n=128; High-UpH 7.0-9.0, n=70). Kaplan-Meier curves indicated that patients in the High-UpH group or with any abnormal imaging finding had a higher rate of hematospermia persistence (both P<0.05). Even after matching between the groups classified by UpH (n=60 each), multivariate analysis showed that UpH level (hazard ratio 0.75, 95% CI: 0.61-0.92; P=0.006) and any abnormal imaging finding (hazard ratio 1.55, 95% CI: 1.04-2.31; P=0.033) were independent predictors of hematospermia duration. In Kaplan-Meier analysis findings of matched cohorts, High-UpH and presence of any abnormal imaging findings remained significantly correlated with higher rate of hematospermia persistence, while further stratification using a combination of these two factors identified a stepwise reduction in that rate (P=0.019). In addition, the proportion of patients with these two factors present simultaneously was significantly higher in the group with hematospermia for two months or more, and especially with a duration of greater than six months, than in the group with a duration of less than two months.

CONCLUSIONS

Although further research is needed, both UpH level and imaging findings of the prostate are considered useful biomarkers for predicting prolonged hematospermia.

Molecular Mechanisms and Risk Factors Related to the Pathogenesis of Peyronie's Disease

Peyronie's disease (PD) is a benign condition caused by plaque formation on the tunica albuginea of the penis. It is associated with penile pain, curvature, and shortening, and contributes to erectile dysfunction, which worsens patient quality of life. In recent years, research into understanding of the detailed mechanisms and risk factors involved in the development of PD has been increasing. In this review, the pathological mechanisms and several closely related signaling pathways, including TGF-β, WNT/β-catenin, Hedgehog, YAP/TAZ, MAPK, ROCK, and PI3K/AKT, are described. Findings regarding cross-talk among these pathways are then discussed to elucidate the complicated cascade behind tunica albuginea fibrosis. Finally, various risk factors including the genes involved in the development of PD are presented and their association with the disease summarized. The purpose of this review is to provide a better understanding regarding the involvement of risk factors in the molecular mechanisms associated with PD pathogenesis, as well as to provide insight into disease prevention and novel therapeutic interventions.

Combination of C-reactive protein/albumin ratio and time to castration resistance enhances prediction of prognosis for patients with metastatic castration-resistant prostate cancer

Objective

This study aimed to identify the prediction accuracy of the combination of C-reactive protein (CRP) albumin ratio (CAR) and time to castration resistance (TTCR) for overall survival (OS) following development of metastatic castration-resistant prostate cancer (mCRPC).

Methods

Clinical data from 98 mCRPC patients treated at our institution from 2009 to 2021 were retrospectively evaluated. Optimal cutoff values for CAR and TTCR to predict lethality were generated by use of a receiver operating curve and Youden's index. The Kaplan-Meier method and Cox proportional hazard regression models for OS were used to analyze the prognostic capabilities of CAR and TTCR. Multiple multivariate Cox models were then constructed based on univariate analysis and their accuracy was validated using the concordance index.

Results

The optimal cutoff values for CAR at the time of mCRPC diagnosis and TTCR were 0.48 and 12 months, respectively. Kaplan-Meier curves indicated that patients with CAR >0.48 or TTCR <12 months had a significantly worse OS (both p < 0.005). Univariate analysis also identified age, hemoglobin, CRP, and performance status as candidate prognostic factors. Furthermore, a multivariate analysis model incorporating those factors and excluding CRP showed CAR and TTCR to be independent prognostic factors. This model had better prognostic accuracy as compared with that containing CRP instead of CAR. The results showed effective stratification of mCRPC patients in terms of OS based on CAR and TTCR (p < 0.0001).

Conclusion

Although further investigation is required, CAR and TTCR used in combination may more accurately predict mCRPC patient prognosis.

Successful treatment of ejaculation pain with silodosin in patient with Zinner syndrome: a case report

Background

Zinner syndrome is a rare congenital anomaly featuring a unilateral seminal vesicle cyst and ipsilateral renal agenesis. While the majority of affected patients are asymptomatic and followed with conservative management, others have symptoms such as micturition, ejaculatory difficulties, and/or pain, thus may require treatment. These patients often undergo an invasive procedure as first-line treatment, such as transurethral resection of the ejaculatory duct, or aspiration and drainage, which reduces pressure within the seminal vesicle cyst, or surgical resection of the seminal vesicle. Reported here is a patient with ejaculation pain and pelvic discomfort associated with Zinner syndrome who was successfully treated in a non-invasive manner with silodosin, an α1-adrenoceptor antagonist.

Case Description

A 37-year-old Japanese male had ejaculation pain and pelvic discomfort associated with Zinner syndrome. Two months of treatment with silodosin, an α1-blocker, resulted in complete pain relief. Thereafter, conservative management with regular follow-up examinations has been conducted for five years, without recurrence of ejaculation pain or other symptoms associated with Zinner syndrome.

Conclusions

This is the first known published case report of a patient with Zinner syndrome treated with silodosin who was completely relieved from ejaculation pain. The effect of α1-adrenoceptor antagonists to inhibit seminal vesicle contraction, as well as cause relaxation of smooth muscles of the urethra and prostate may contribute to reduce pain associated with ejaculation. We concluded that silodosin treatment should be attempted in affected patients before considering surgical treatment.

[A Study of Factors Affecting Febrile Urinary Tract Infection Following Ureterorenoscopic Lithotripsy]

Febrile urinary tract infection (f-UTI) is a common complication after ureterorenoscopic lithotripsy (URSL) but is sometimes lethal. In this article, we analyzed the factors of post URSL f-UTI. We retrospectively evaluated the association between the development of f-UTI and patients, stones, and perioperative factors in 695 cases in which URSL was performed at our institution from September 2015 to 2018. Seventy-six of the 695 patients (10.9%) had postoperative f-UTI. Elderly (p＝0.013), female (p＝0.02), and hypertension (p＝0.001) patients had significantly higher rates of f-UTI. Renal stone (p＝0.001) cases showed significantly higher rates of f-UTI. Preoperative urine positive culture (p＝0.045), preoperative f-UTI (p＜0.001), URSL procedure using flexible ureteroscopy (p＝0.048), non-stone-free (p＝0.006), long operation time (p＝0.011), preoperative urinary stent insertion due to preoperative f-UTI (p＜0.001), were factors associated with post-operative f-UTI. Multivariate analysis revealed that hypertension (OR＝2.08, p＝0.008) and preoperative f-UTI (OR＝3.739, p＝0.033) were independent factors of postoperative f-UTI. Patients with hypertension or preoperative f-UTI should be managed more carefully during the perioperative period, suspecting that they are more likely to develop postoperative f-UTI.

Summary of the clinical practice manual for late-onset hypogonadism

Testosterone plays an important role in maintaining both physical and mental function. Age-related testosterone depletion contributes to the development of angina, arteriosclerosis, obesity, metabolic syndrome, dementia, frailty, and a range of other conditions. A condition involving age-related testosterone depletion and the associated clinical symptoms is defined as late-onset hypogonadism (LOH). LOH is treated by testosterone replacement therapy. Indications for testosterone replacement therapy are determined by evaluating symptoms and signs.

Significant inverse association of testosterone level with penile deformity severity in Japanese males with Peyronie's disease

OBJECTIVES

We evaluated the relationship between penile curvature and testosterone in Peyronie's disease patients treated in Japan.

METHODS

Data were obtained from 109 patients with Peyronie's disease treated with surgery at our hospital between April 2004 and December 2019. Penile deformity assessment was based on findings of a rigid erection induced by intracavernosal injection. Low total testosterone level was defined as <300 ng/dl. Patients were divided into two groups according to curvature severity (I, <60°; II ≥60°), then clinical factors including total testosterone were compared. Uni- and multivariate logistic regression analyses were performed to identify factors predicting severe penile deformity (≥60°).

RESULTS

For all patients, mean total testosterone was 469 ng/dl and median curvature was 50°, with a significant inverse correlation found between curvature and testosterone level (p < 0.0001). Group I and II patients numbered 55 and 54, respectively. Mean total testosterone for Group II was 397 ng/dl, significantly lower than Group I (539 ng/dl). Median curvature in 15 patients with a low testosterone level was 80°, significantly higher than those with a normal testosterone range (50°). Univariable and multivariable logistic regression analysis indicated total testosterone, follicle stimulating hormone, and C-reactive protein as significant factors correlated with severe penile deformity, among which total testosterone was most relevant.

CONCLUSION

The present findings confirmed that penile deformity severity is correlated with testosterone level in Japanese males with Peyronie's disease.

ABO Blood Type and Risk of Peyronie's Disease in Japanese Males

PURPOSE

Although multiple mechanisms associated with Peyronie's disease (PD) have been proposed, details regarding etiologic factors, especially genetic, remain unclear. We examined the relationship of the ABO blood type system, known as a genetic factor associated with susceptibility to a number of diseases, with PD in Japanese males.

MATERIALS AND METHODS

We compared 202 Japanese PD patients treated with surgery at our hospital between March 2004 and December 2019 with 846 randomly selected non-PD male patients who underwent urological surgery during the same period regarding distribution of ABO blood types. In addition, we assessed the risk of PD according to blood type group among all study participants using odds ratio (OR) and 95% confidence interval (CI) calculations.

RESULTS

The distribution of individual blood types in the control group was nearly the same as that in the general Japanese population. In contrast, O, A, B, and AB blood types were noted in 37.6%, 36.1%, 14.9% and 11.4%, respectively, of the PD patients, which was significantly different from the control group, where blood type O was found in 29.1% and B in 23.2% (p<0.05). Our results showed that as compared with patients with blood group B, those with another blood type were more likely to develop PD, among which type O had a significantly increased OR of 2.018 (CI, 1.271-3.205).

CONCLUSIONS

These are the first reported results showing that ABO blood type may be associated with risk of PD, though further investigations are needed.

Impact of eliminating urethral catheterization following ureterorenoscopic lithotripsy

OBJECTIVES

To show that elimination of a urethral catheter in ureterorenoscopic lithotripsy cases is not disadvantageous.

METHODS

We reviewed 164 non-catheterized patients (experimental group) and 656 catheterized patients (control group) with renal or ureteral stones treated at our institution. Inclusion criteria were initial operation, patient age 18 to 75 years, no dysuria, and no preoperative febrile urinary tract infection due to calculi. The primary areas of evaluation were patient background, stone characteristics, perioperative factors, and postoperative evaluation results.

RESULTS

The proportion of women was significantly lower (24.4% vs 37.2%; P = 0.01) and the proportion of multiple stone cases was significantly higher (34.9% vs 19.2%; P < 0.001) in the experimental as compared to the control group, while there were no significant differences for patient background or stone characteristics. The percentages of short-term preoperative stent insertion (72.0% vs 33.0%; P = 0.009) and negative preoperative urine culture cases (58.0% vs 23.0%; P < 0.001) were significantly higher in the experimental than in the control group, with no differences regarding other perioperative factors. There was no significant difference for complete stone clearance rate between the groups (P = 0.339), while only one patient underwent re-catheterization and there were no cases of urinary retention. Interestingly, the rate of postoperative febrile urinary tract infection was significantly lower (P = 0.024) in the experimental (5.7%) than in the control (9.0%) group.

CONCLUSION

Postoperative urethral catheterization can be eliminated in low-risk ureterorenoscopic lithotripsy cases, although additional studies are needed.

A method for utilizing automated machine learning for histopathological classification of testis based on Johnsen scores

We examined whether a tool for determining Johnsen scores automatically using artificial intelligence (AI) could be used in place of traditional Johnsen scoring to support pathologists’ evaluations. Average precision, precision, and recall were assessed by the Google Cloud AutoML Vision platform. We obtained testicular tissues for 275 patients and were able to use haematoxylin and eosin (H&E)-stained glass microscope slides from 264 patients. In addition, we cut out of parts of the histopathology images (5.0 × 5.0 cm) for expansion of Johnsen’s characteristic areas with seminiferous tubules. We defined four labels: Johnsen score 1–3, 4–5, 6–7, and 8–10 to distinguish Johnsen scores in clinical practice. All images were uploaded to the Google Cloud AutoML Vision platform. We obtained a dataset of 7155 images at magnification 400× and a dataset of 9822 expansion images for the 5.0 × 5.0 cm cutouts. For the 400× magnification image dataset, the average precision (positive predictive value) of the algorithm was 82.6%, precision was 80.31%, and recall was 60.96%. For the expansion image dataset (5.0 × 5.0 cm), the average precision was 99.5%, precision was 96.29%, and recall was 96.23%. This is the first report of an AI-based algorithm for predicting Johnsen scores.

Temporary pacemaker insertion for severe bradycardia following pneumoperitoneum during robot-assisted radical prostatectomy: a case report

Background

Pneumoperitoneum to maintain a constant gas flow to assist various surgeries is known to cause severe bradycardia and has been linked to heart failure;; however, a recent study demonstrated that it is not linked to poorer surgical outcomes; accordingly, it does not require routine preventive measures. Thus, whether there is a link between sudden bradycardia development and surgical procedures is controversial. We report the case of severe bradycardia that occurred along with a complete atrioventricular block (CAVB) during peritoneum creation in robot-assisted radical prostatectomy (RARP).

Case presentation

A 72-year-old man presented at our hospital with prostate cancer and underwent RARP. After pneumoperitoneum, severe bradycardia and CAVB were observed; thus, the surgery was extended by inserting a temporary pacemaker (TPM).

Conclusion

Because of the difficulty in performing emergency procedures in robot-assisted surgeries, the current case is reported to provide an awareness that surgeons should be cautious of the possible complication of bradycardia and CAVB during such operations, and thus should take steps necessary for managing induction of such conditions.

Intestinal malrotation in a patient who underwent radical cystectomy and ileal conduit construction: A case report

A 74-year-old male underwent laparoscopic radical cystectomy for invasive bladder cancer with open surgery for lymph node dissection and urinary diversion (ileal conduit). During the surgery, intestinal malrotation was diagnosed and Ladd procedure was performed. Ileal conduit was performed on the left side after considering the course of mesentery. Although a final diagnosis was reached during the surgery in this case, the presence of intestinal malrotation can be suspected based on the findings of contrast-enhanced computed tomography images obtained before the surgery. Images should be carefully inspected to detect intestinal malrotation when planning urinary diversion involving the intestinal tract.

Influence of lifestyle choices on risks of CYP1B1 polymorphisms for prostate cancer

Cytochrome P450 1B1 (CYP1B1) converts xenobiotics to carcinogens and how lifestyle choices may interact with CYP1B1 polymorphisms and affect prostate cancer risk was assessed. Blood genomic DNA from a Caucasian population was analysed at polymorphic sites of the 5' untranslated region of CYP1B1 using TaqMan genotyping assays. Overall, drinker status and minor alleles at rs2551188, rs2567206 and rs10175368 were associated with prostate cancer. Linkage was observed between rs2551188, rs2567206, rs2567207 and rs10175368, and the G-C-T-G haplotype (major allele at respective sites) was decreased in cancer. Interestingly when classified by lifestyle factors, no associations of genotypes were found for non-smokers and non-drinkers, whereas on the contrary, minor type at rs2567206 and rs10175368 increased and major G-C-T-G decreased risk for cancer among smokers and drinkers. Interestingly, rs2551188, rs2567206 and rs10175368 minor genotypes correlated with increased tissue CYP1B1 as determined by immunohistochemistry. Further, rs10175368 enhanced luciferase activity and mobility shift show stronger binding of nuclear factor for the minor allele. These results demonstrate smoking and alcohol consumption to modify the risks of CYP1B1 polymorphisms for prostate cancer which may be through rs10175368, and this is of importance in understanding their role in the pathogenesis and as a biomarker for this disease.

Abstract 1242: Differences of cytochrome P450 1B1 polymorphisms on prostate cancer risk between races

Prostate cancer is the most common cancer among men in the United States but when comparing between races, rates are much higher in African-Americans (AfA) compared to Caucasians (Cau). Reasons for this discrepancy are unknown but studies have shown that polymorphisms of cytochrome P450 1B1 (CYP1B1), a gene that activates carcinogens, to be involved in prostate cancer pathogenesis. In this study, how race influences CYP1B1 polymorphisms and prostate cancer risk were investigated. Blood genomic DNA from a Cau (469 controls, 500 prostate cancer), AfA (152 controls, 218 cases) and Japanese (JPN) (131 controls, 177 cases) population were obtained. Eight polymorphic sites of the promoter or 5'-untranslated region of CYP1B1 (rs2551188 G to A, rs2567206 C to T, rs2567207 T to C, rs162556 T to C, rs10175368 G to A, rs163090 T to A, rs162330 T to G, and rs162331 A to G) were analyzed using Taqman genotyping assays and sequence-specific PCR, and genotyping results tabulated. Also, CYP1B1 protein expression was determined in 52 Cau benign prostatic hyperplasia specimens and levels categorized by polymorphic sites. Racial differences for prostate cancer risk due to CYP1B1 polymorphisms were observed. In Cau, minor alleles rs2551188 A, rs2567206 T and rs10175368 A showed increased risk for cancer (P&lt;0.05). Linkage was observed between rs2551188-rs2567206-rs2567207-rs10175368 and the major G-C-T-G haplotype was reduced in cancer cases (P&lt;0.001). Interestingly when analyzing prostatic tissue specimens, minor genotypes of rs2551188 (P&lt;0.05), rs2567206 (P&lt;0.05) and rs10175368 (Ptrend=0.065) displayed higher levels and major G-C-T-G haplotype lower levels (P&lt;0.05) of CYP1B1 protein expression, which were consistent with genotyping results. For AfA, minor rs2551188 A allele decreased risk for prostate cancer (P&lt;0.001). Rs163090-rs162331 were linked and the minor A-G haplotype displayed a reduced prostate cancer risk (P&lt;0.05). Among JPN, minor rs2567206 T allele also reduced cancer risk (P&lt;0.05). Two sets of linkages, rs2551188-rs2567206-rs2567207-rs162556-rs10175368 and rs163090-rs162330-rs162331 were observed and the minor A-T-C-T-A and major A-T-A haplotypes respectively, showed a decreased risk for cancer (P&lt;0.01). These results suggest a differential effect of CYP1B1 polymorphisms for prostate cancer risk between races and these results are important in understanding its role in this disease.

Citation Format: Taku Kato, Yutaka Hashimoto, Ryan Wong, Yozo Mitsui, Shigekatsu Maekawa, Soichiro Yamamura, Shahana Majid, Sharanjot Saini, Varahram Shahryari, Laura Tabatabai, Hiroaki Shiina, Rajvir Dahiya, Takashi Deguchi, Yuichiro Tanaka. Differences of cytochrome P450 1B1 polymorphisms on prostate cancer risk between races [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 1242.

Cytochrome P450 1B1 inhibition suppresses tumorigenicity of prostate cancer via caspase-1 activation

Cytochrome P450 1B1 (CYP1B1) is recognized as a universal tumor biomarker and a feasible therapeutic target due to its specific overexpression in cancer tissues. Despite its up-regulation in prostate cancer (PCa), biological significance and clinicopathological features of CYP1B1 are still elusive. Here, we show that overexpression or hyperactivation of CYP1B1 stimulated proliferative, migratory and invasive potential of non-tumorigenic PCa cells. Attenuation of CYP1B1 with its specific small hairpin (sh) RNAs greatly reduced proliferation through apoptotic cell death and impaired migration and invasion in PCa cells. Intratumoral injection of CYP1B1 shRNA attenuated growth of pre-existing tumors. The antitumor effect of CYP1B1 shRNA was also observed in prostate tumor xenograft mouse models. Among the genes altered by CYP1B1 knockdown, reduction of caspase-1 (CASP1) activity attenuated the antitumor effect of CYP1B1 inhibition. Indeed, CYP1B1 regulates CASP1 expression or activity. Finally, CYP1B1 expression was increased in higher grades of PCa and overall survival was significantly reduced in patients with high levels of CYP1B1 protein. CYP1B1 expression was reversely associated with CASP1 expression in clinical tissue samples. Together, our results demonstrate that CYP1B1 regulates PCa tumorigenesis by inhibiting CASP1 activation. Thus, the CYP1B1-CASP1 axis may be useful as a potential biomarker and a therapeutic target for PCa.

Acute Inflammatory Syndrome Paradoxically Induced by De Novo Purine Inhibitors Synthesis Before Renal Transplantation: A Case Report and Review of the Literature

BACKGROUND

Mycophenolate mofetil (MMF) and mizoribine (MZR) are increasingly used as immunosuppressive agents for organ transplantation and chronic inflammation. We report a patient with rheumatoid arthritis who had an acute inflammatory syndrome triggered by preoperative immunosuppression therapy with both MMF and MZR.

CASE REPORT

A 41-year-old woman with IgA nephropathy was referred to our department for living donor renal transplantation. She had rheumatoid arthritis that was adequately treated with prednisolone 5 mg once a day and salazosulfapyridine 2000 mg once a day. MMF 1000 mg twice a day was started for desensitization therapy. Three days later, the patient developed arthritis in the joints of her left hand and elevated inflammatory markers. On day 7, MMF was switched to MZR 150 mg 3 times a day. However, the symptoms extended to both shoulders and the joints of the right foot; MZR was discontinued. The arthritis and inflammatory markers improved. Two months later, the patient was rechallenged with MMF followed by MZR, resulting in a similar clinical course as previously. Tacrolimus (TAC) 3 mg twice a day and everolimus (EVL) 0.5 mg twice a day were introduced as alternative immunosuppressant therapies. No arthritis occurred. ABO-compatible living donor renal transplantation was successfully performed. The patient received TAC, EVL, prednisolone, rituximab, and basiliximab, and her postoperative course was uneventful without arthritis or rejection. At 9 months postoperatively, the serum creatinine was 0.79 mg/dL.

CONCLUSIONS

Acute inflammatory syndrome is an extremely rare complication triggered by preoperative immunosuppression therapy. If antimetabolites cannot be used in immunologically high-risk patients, transplantation becomes very difficult. Clinicians should keep in mind this paradoxical reaction.

Functional role and tobacco smoking effects on methylation of CYP1A1 gene in prostate cancer

Cytochrome P450 (CYP) 1A1 is a phase I enzyme that can activate various compounds into reactive forms and thus, may contribute to carcinogenesis. In this study, we investigated the expression, methylation status, and functional role of CYP1A1 on prostate cancer cells. Increased expression of CYP1A1 was observed in all cancer lines (PC-3, LNCaP, and DU145) compared to BPH-1 (P < 0.05); and was enhanced further by 5-aza-2′-deoxycytidine treatment (P < 0.01). Methylation-specific PCR (MSP) and sequencing of bisulfite-modified DNA of the xenobiotic response element (XRE) enhancer site XRE-1383 indicated promoter methylation as a regulator of CYP1A1 expression. In tissue, microarrays showed higher immunostaining of CYP1A1 in prostate cancer than normal and benign prostatic hyperplasia (BPH; P < 0.001), and methylation analyses in clinical specimens revealed significantly lower methylation levels in cancer compared to BPH at all enhancer sites analyzed (XRE-1383, XRE-983, XRE-895; P < 0.01). Interestingly, smoking affected the XRE-1383 site where the methylation level was much lower in cancer tissues from smokers than non-smokers (P < 0.05). CYP1A1 levels are thus increased in prostate cancer and to determine the functional effect of CYP1A1 on cells, we depleted the gene in LNCaP and DU145 by siRNA. We observe that CYP1A1 knockdown decreased cell proliferation (P < 0.05) and increased apoptosis (P < 0.01) in both cell lines. We analyzed genes affected by CYP1A1 silencing and found that apoptosis-related BCL2 was significantly down-regulated. This study supports an oncogenic role for CYP1A1 in prostate cancer via promoter hypomethylation that is influenced by tobacco smoking, indicating CYP1A1 to be a promising target for prostate cancer treatment.

The role of miR-24 as a race related genetic factor in prostate cancer

The incidence of prostate cancer (PCa) among African-Americans (AfA) is significantly higher than Caucasian-Americans (CaA) but the genetic basis for this disparity is not known. To address this problem, we analyzed miRNA expression in AfA (n = 81) and CaA (n = 51) PCa patients. Here, we found that miR-24 is differentially expressed in AfA and CaA PCa patients and attempt to clarify its role in AfA patients. Also, the public sequencing data of the miR-24 promoter confirmed that it was highly methylated and down-regulated in PCa patients. Utilizing a VAMCSF and NDRI patient cohorts, we discovered that miR-24 expression was linked to a racial difference between AfA/CaA PCa patients. Interestingly, miR-24 was restored after treatment of PCa cells with 5Aza-CdR in an AfA cell line (MDA-PCa-2b), while restoration of miR-24 was not observed in CaA cells, DU-145. Ectopic expression of miR-24 showed decreased growth and induced apoptosis, though the effect was less in the CaA cell line compared to the AfA cell line. Finally, we found unique changes in biological pathways and processes associated with miR-24 transfected AfA cells by quantitative PCR-based gene expression array. Evaluation of the altered pathways showed that AR, IGF1, IGFBP5 and ETV1 were markedly decreased in the AfA derived cell line compared with CaA cells, and there was a reciprocal regulatory relationship of miR-24/target expression in prostate cancer patients. These results demonstrate that miR-24 may be a central regulator of key events that contribute to race-related tumorigenesis and has potential to be a therapeutic agent for PCa treatment.

Abstract 462: The role of miR-24 as a race-related genetic factor in prostate cancer

The incidence of prostate cancer (PCa) among African-Americans (AfA) is significantly higher than Caucasian-Americans (CaA) but the genetic basis for this disparity is not known. To address this problem, we analyzed miRNA expression in AfA (n=81) and CaA (n=51) PCa patients. Here, we found that miR-24 is differentially expressed in AfA and CaA PCa patients and attempt to clarify its role in AfA patients. Also, the public sequencing data of the miR-24 promoter confirmed that it was highly methylated and down-regulated in PCa patients. Utilizing a VAMCSF and NDRI patient cohorts, we discovered that miR-24 expression was linked to a racial difference between AfA/CaA PCa patients. Interestingly, miR-24 was restored after treatment of PCa cells with 5Aza-CdR in an AfA cell line (MDA-PCa-2b), while restoration of miR-24 was not observed in CaA cells, DU-145. Ectopic expression of miR-24 showed decreased growth and induced apoptosis, though the effect was less in the CaA cell line compared to the AfA cell line. Finally, we found unique changes in biological pathways and processes associated with miR-24 transfected AfA cells by quantitative PCR-based gene expression array. Evaluation of the altered pathways showed that AR, PDPK1, IGF1, and IGFBP5 were markedly decreased in the AfA derived cell line compared with CaA cells, and there was a reciprocal regulatory relationship of miR-24/target expression in prostate cancer patients. These results demonstrate that miR-24 may be a central regulator of key events that contribute to race-related tumorigenesis and has potential to be a therapeutic agent for PCa treatment.

Citation Format: Yutaka Hashimoto, Marisa Shiina, Taku Kato, Soichiro Yamamura, Yuichiro Tanaka, Shahana Majid, Sharanjot Saini, Varahram Shahryari, Priyanka Kulkarni, Pritha Dasgupta, Yozo Mitsui, Mitsuho Sumida, Guoren Deng, Laura Tabatabai, Deepak Kumar, Rajvir Dahiya. The role of miR-24 as a race-related genetic factor in prostate cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 462. doi:10.1158/1538-7445.AM2017-462

Abstract 5749: VCAN promotes clear cell renal cell carcinoma tumor progression and metastasis, and predicts poor prognosis

Introduction and Objectives: Although versican (VCAN) is known to promote tumor progression and enhance metastasis of several types of cancers, its role in clear cell renal cell carcinoma (ccRCC) remains unknown. Interestingly, a recent report showed that VCAN is an important target of chromosomal 5q gain, one of the most prevalent genetic abnormalities in ccRCC cases. In the present study, we investigated whether VCAN expression is associated with the pathogenesis of ccRCC.

Methods: VCAN expression was analyzed in 3 RCC and normal kidney cell lines, as well as 84 matched ccRCC and normal renal tissues. We also performed various functional analyses of growth and progression properties using VCAN-depleted ccRCC cells. Microarray analysis was then employed to investigate the target genes of the pathway involved in ccRCC tumorigenesis and development.

Results: There are 4 isoforms of VCAN containing the N-terminal globular (G1 domain) and C-terminal globular (G3 domain) domains, each of which was found to be over-expressed in the ccRCC samples as compared to the controls. Higher VCAN expression was significantly correlated with metastasis (p&lt;0.001) and worse 5-year overall survival after a radical nephrectomy (p=0.014). In vitro, VCAN knockdown by siRNA in Caki-2 and 786-O cells significantly decreased cell proliferation and increased apoptosis, and was also found to be associated with alteration of several TNF signaling-related genes, such as TNF-α, BID, and BAK. Furthermore, VCAN depletion markedly decreased cell migration and invasion associated with reduced MMP7 and CXCR4 levels.

Conclusion: Our results demonstrate that VCAN promotes ccRCC tumorigenesis and metastasis, showing it to be an attractive novel target for diagnostic, prognostic, and therapeutic strategies for affected patients.

Note: This abstract was not presented at the meeting.

Citation Format: Yozo Mitsui, Taku Kato, Shigekatsu Maekawa, Yutaka Hashimoto, Marisa Shiina, Mitsuho Imai Sumida, Ryan Kenji Wong, Soichiro Yamamura, Varahram Shahryari, Shahana Majid, Sharanjot Saini, Guoren Deng, Rajvir Dahiya, Koichi Nakajima, Yuichiro Tanaka. VCAN promotes clear cell renal cell carcinoma tumor progression and metastasis, and predicts poor prognosis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5749. doi:10.1158/1538-7445.AM2017-5749

Versican Promotes Tumor Progression, Metastasis and Predicts Poor Prognosis in Renal Carcinoma

The proteoglycan versican (VCAN) promotes tumor progression and enhances metastasis in several cancers; however, its role in clear cell renal cell carcinoma (ccRCC) remains unknown. Recent evidence suggests that VCAN is an important target of chromosomal 5q gain, one of the most prevalent genetic abnormalities in ccRCC. Thus, we investigated whether VCAN expression is associated with the pathogenesis of ccRCC. VCAN expression was analyzed using three RCC and normal kidney cell lines as well as a clinical cohort of 84 matched ccRCC and normal renal tissues. Functional analyses on growth and progression properties were performed using VCAN-depleted ccRCC cells. Microarray expression profiling was employed to investigate the target genes and biologic pathways involved in VCAN-mediated ccRCC carcinogenesis. ccRCC had elevated VCAN expression in comparison with normal kidney in both cell lines and clinical specimens. The elevated expression of VCAN was significantly correlated with metastasis (P < 0.001) and worse 5-year overall survival after radical nephrectomy (P = 0.014). In vitro, VCAN knockdown significantly decreased cell proliferation and increased apoptosis in Caki-2 and 786-O cells, and this was associated with alteration of several TNF signaling-related genes such as TNFα, BID, and BAK Furthermore, VCAN depletion markedly decreased cell migration and invasion which correlated with reduction of MMP7 and CXCR4. These results demonstrate that VCAN promotes ccRCC tumorigenesis and metastasis and thus is an attractive target for novel diagnostic, prognostic, and therapeutic strategies.Implications: This study highlights the oncogenic role of VCAN in renal cell carcinogenesis and suggests that this gene has therapeutic and/or biomarker potential for renal cell cancer. Mol Cancer Res; 15(7); 884-95. ©2017 AACR.

Differential expression of miR-34b and androgen receptor pathway regulate prostate cancer aggressiveness between African-Americans and Caucasians

African-Americans are diagnosed with more aggressive prostate cancers and have worse survival than Caucasians, however a comprehensive understanding of this health disparity remains unclear. To clarify the mechanisms leading to this disparity, we analyzed the potential involvement of miR-34b expression in African-Americans and Caucasians. miR-34b functions as a tumor suppressor and has a multi-functional role, through regulation of cell proliferation, cell cycle and apoptosis. We found that miR-34b expression is lower in human prostate cancer tissues from African-Americans compared to Caucasians. DNA hypermethylation of the miR-34b-3p promoter region showed significantly higher methylation in prostate cancer compared to normal samples. We then sequenced the promoter region of miR-34b-3p and found a chromosomal deletion in miR-34b in African-American prostate cancer cell line (MDA-PCA-2b) and not in Caucasian cell line (DU-145). We found that AR and ETV1 genes are differentially expressed in MDA-PCa-2b and DU-145 cells after overexpression of miR-34b. Direct interaction of miR-34b with the 3' untranslated region of AR and ETV1 was validated by luciferase reporter assay. We found that miR-34b downregulation in African-Americans is inversely correlated with high AR levels that lead to increased cell proliferation. Overexpression of miR-34b in cell lines showed higher inhibition of cell proliferation, apoptosis and G1 arrest in the African-American cells (MDA-PCa-2b) compared to Caucasian cell line (DU-145). Taken together, our results show that differential expression of miR-34b and AR are associated with prostate cancer aggressiveness in African-Americans.

MicroRNA-383 located in frequently deleted chromosomal locus 8p22 regulates CD44 in prostate cancer

A major genomic alteration in prostate cancer (PCa) is frequent loss of chromosome (chr) 8p with a common region of loss of heterozygosity (LOH) at chr8p22 locus. Genomic studies implicate this locus in the initiation of clinically significant PCa and with progression to metastatic disease. However, the genes within this region have not been fully characterized to date. Here we demonstrate for the first time that a microRNA component of this region –miR-383- is frequently downregulated in prostate cancer, plays a critical role in determining tumor initiating potential and is involved in prostate cancer metastasis via direct regulation of CD44, a ubiquitous marker of PCa tumor initiating cells (TICs)/ stem cells. Expression analyses of miR-383 in PCa clinical tissues established that low miR-383 expression is associated with poor prognosis. Functional data suggests that miR-383 regulates PCa tumor initiating/ stem-like cells via CD44 regulation. Ectopic expression of miR-383 inhibited tumor initiating capacity of CD44+ PCa cells. Also, ‘anti-metastatic’ effects of ectopic miR-383 expression were observed in a PCa experimental metastasis model. In view of our results, we propose that frequent loss of miR-383 at chr8p22 region leads to tumor initiation and prostate cancer metastasis. Thus, we have identified a novel finding that associates a long observed genomic alteration to PCa stemness and metastasis. Our data suggests that restoration of miR-383 expression may be an effective therapeutic modality against PCa. Importantly, we identified miR-383 as a novel PCa tissue diagnostic biomarker with a potential that outperforms that of serum PSA.

Oncogenic microRNA-4534 regulates PTEN pathway in prostate cancer

Prostate carcinogenesis involves alterations in several signaling pathways, the most prominent being the PI3K/AKT pathway. This pathway is constitutively active and drives prostate cancer (PCa) progression to advanced metastatic disease. PTEN, a critical tumor and metastasis suppressor gene negatively regulates cell survival, proliferation, migration and angiogenesis via the PI3K/Akt pathway. PTEN is mutated, downregulated/dysfunctional in many cancers and its dysregulation correlates with poor prognosis in PCa. Here, we demonstrate that microRNA-4534 (miR-4534) is overexpressed in PCa and show that miR-4534 is hypermethylated in normal tissues and cell lines compared to PCa tissues/cells. miR-4534 exerts its oncogenic effects partly by downregulating the tumor suppressor PTEN gene. Knockdown of miR-4534 impaired cell proliferation, migration/invasion and induced G0/G1 cell cycle arrest and apoptosis in PCa. Suppression of miR-4534 and its effects on tumor growth was confirmed in a xenograft mouse model. We performed parallel experiments in non-cancer RWPE1 cells by overexpessing miR-4534 followed by functional assays. Overexpression of miR-4534 induced pro-cancerous characteristics in this non-cancer cell line. Statistical analyses revealed that miR-4534 has potential to independently distinguish malignant from normal tissues and positively correlated with poor overall and PSA recurrence free survival. Taken together, our results show that depletion of miR-4534 in PCa induces a tumor suppressor phenotype partly through induction of PTEN. These results have important implications for identifying and defining the role of new PTEN regulators such as microRNAs in prostate tumorigenesis. Understanding aberrantly overexpressed miR-4534 and its downregulation of PTEN will provide mechanistic insight and therapeutic targets for PCa therapy.

Pre-clinical Orthotopic Murine Model of Human Prostate Cancer

To study the multifaceted biology of prostate cancer, pre-clinical in vivo models offer a range of options to uncover critical biological information about this disease. The human orthotopic prostate cancer xenograft mouse model provides a useful alternative approach for understanding the specific interactions between genetically and molecularly altered tumor cells, their organ microenvironment, and for evaluation of efficacy of therapeutic regimens. This is a well characterized model designed to study the molecular events of primary tumor development and it recapitulates the early events in the metastatic cascade prior to embolism and entry of tumor cells into the circulation. Thus it allows elucidation of molecular mechanisms underlying the initial phase of metastatic disease. In addition, this model can annotate drug targets of clinical relevance and is a valuable tool to study prostate cancer progression. In this manuscript we describe a detailed procedure to establish a human orthotopic prostate cancer xenograft mouse model.

Abstract 1934: MicroRNA-383 located in frequently deleted chromosomal locus 8p22 regulates prostate cancer stem cell marker CD44

A major genomic alteration in prostate cancer (PCa) is frequent loss of chromosome (chr) 8p with a common region of loss of heterozygosity (LOH) at chr8p22 locus. Genomic studies implicate this locus in the initiation of clinically significant PCa and with progression to metastatic disease. However, the genes within this region have not been fully characterized to date. Here we demonstrate for the first time that a microRNA component of this region -miR-383- is frequently downregulated in prostate cancer, plays a critical role in determining tumor initiating potential and is involved in prostate cancer metastasis via direct regulation of CD44, a ubiquitous marker of PCa tumor initiating cells (TICs)/ stem cells. Expression analyses of miR-383 in PCa clinical tissues established that low miR-383 expression is associated with poor prognosis. Functional data suggests that miR-383 regulates PCa tumor initiating/ stem-like cells via CD44 regulation. Ectopic expression of miR-383 inhibited tumor initiating capacity of CD44+ PCa cells. Also, ‘anti-metastatic’ effects of ectopic miR-383 expression were observed in a PCa experimental metastasis model. In view of our results, we propose that frequent loss of miR-383 at chr8p22 region leads to tumor initiation and prostate cancer metastasis. Thus, we have identified a novel finding that associates a long observed genomic alteration to PCa stemness and metastasis. Our data suggests that restoration of miR-383 expression may be an effective therapeutic modality against PCa relapse and metastasis. Importantly, we identified miR-383 as a novel PCa diagnostic biomarker with potential that outperforms that of serum PSA.

Citation Format: Nathan Bucay, Kiran Sekhon, Varahram Shahryari, Yozo Mitsui, Guoren Deng, Z. Laura Tabatabai, Shahana Majid, Soichiro Yamamura, Rajvir Dahiya, Yuichiro Tanaka, Sharanjot Saini. MicroRNA-383 located in frequently deleted chromosomal locus 8p22 regulates prostate cancer stem cell marker CD44. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1934.

Abstract 1155: Inhibitory effect of CYP1B1 on antitumor activities induced by dysregulated CDC20 and DAPK1 in renal cell carcinoma

Introduction and Objective: Cytochrome P450 1B1 (CYP1B1) has been shown to be up-regulated in many types of cancer including renal cell carcinoma (RCC). Several reports have shown that CYP1B1 can influence the regulation of tumor development; however, its role in RCC has not been well investigated. The aim of the present study was to determine the functional effects of CYP1B1 gene on tumorigenesis in RCC. Methods: Expression of CYP1B1 was determined in RCC cell lines, and tissue microarrays of 96 RCC and 25 normal tissues. To determine the biological significance of CYP1B1 in RCC progression, we silenced the gene in Caki-1 and 769-P cells by RNA interference and performed various functional analyses.

Results: First, we confirmed that CYP1B1 protein expression was significantly higher in RCC cell lines compared to normal kidney tissue. This trend was also observed in RCC samples (p&lt;0.01). Interestingly, CYP1B1 expression was associated with tumor grade and stage. Next, we silenced the gene in Caki-1 and 769-P cells by RNA interference and performed various functional analyses to determine the biological significance of CYP1B1 in RCC progression. Inhibition of CYP1B1 expression resulted in decreased cell proliferation, migration and invasion of RCC cells. In addition, reduction of CYP1B1 induced cellular apoptosis in Caki-1. We also found that these anti-tumor effects on RCC cells caused by CYP1B1 depletion may be due to alteration of CDC20 and DAPK1 expression based on gene microarray and confirmed by real-time PCR. Interestingly, CYP1B1 expression was associated with CDC20 and DAPK1 expression in clinical samples.

Conclusions: CYP1B1 may promote RCC development by inducing CDC20 expression and inhibiting apoptosis through the down-regulation of DAPK1. Our results demonstrate that CYP1B1 can be a potential tumor biomarker and a target for anticancer therapy in RCC.

Citation Format: Yozo Mitsui, Inik Chang, Shinichiro Fukuhar, Hiroshi Hirata, Ryan Kenji Wong, Soichiro Yamamura, Varahram Shahryari, Guoren Deng, Saini Sharanjot, Shahana Majid, Hiroaki Shiina, Rajvir Dahiya, Yuichiro Tanaka. Inhibitory effect of CYP1B1 on antitumor activities induced by dysregulated CDC20 and DAPK1 in renal cell carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1155.

Abstract 956: Anticancer effects of silibinin-induced small nucleolar RNA 11B on bladder cancer cells

Silibinin is the major active constituent of silymarin, an extract of milk thistle seeds. Silibinin has been shown to have significant anti-cancer effects in a variety of malignancies. However, the molecular mechanisms of silibinin action in bladder cancer have not been reported. In the present study, we found that silibinin (10 μM) significantly suppressed proliferation and invasion of T24 and UM-UC-3 bladder cancer cells. We analyzed various pathways as possible mechanisms of silibinin action using RNA-Seq technology in bladder cancer cell lines. Analysis of RNA-seq data identified silibinin targets that down-regulate the actin cytoskeleton pathway. Analysis of RNA-seq data also identified the mitogen-activated protein (MAP) kinase signaling pathway as a silibinin-down-regulated pathway. These pathways were also found to crosstalk through Ras and phosphatidylinositide 3-kinase (PI3K). These data show that silibinin anti-cancer effects are through down-regulation of actin cytoskeleton and MAP kinase pathways in bladder cancer. We also found that silibinin induced small nucleolar RNA 11B (SNORD11B) and that SNORD11B suppressed proliferation and invasion of bladder cancer cells. We will discuss the pathway of the anti-cancer effects of SNORD11B.

Citation Format: Soichiro Yamamura, Yozo Mitsui, Shahana Majid, Hannah Nip, Nathan Bucay, Sharanjot Saini, Guoren Deng, Varahram Shahryary, Rajvir Dahiya, Yuichiro Tanaka. Anticancer effects of silibinin-induced small nucleolar RNA 11B on bladder cancer cells. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 956.

Abstract 1619: MicroRNA-466 regulates bone metastasis by targeting RUNX2 in prostate cancer

MicroRNAs are small, non-coding RNAs that regulate gene expression by targeted repression of transcription and translation. The main objective of this study was to investigate the role of microRNA-466 (miR-466) in prostate carcinogenesis (PC). The expression of miR-466 was significantly suppressed in PC tissue samples and cell lines (PC3, Du145, LNCaP, MDaPCa2b and LAPC4) when compared with normal tissues and a non-malignant cell line (RWPE1). Receiver operating curve analysis showed that miR-466 expression is an independent diagnostic predictor to discriminate between normal and tumor cases. Functionally ectopic expression of miR-466 caused a robust decrease in cell migration, invasion and proliferation of prostate cancer cells. We found that miR-466 exerted these functional effects by directly targeting the oncogenic RUNX2, a key transcription factor in PC. Over-expression of miR-466 in prostate cancer cells suppressed luciferase activity of reporter plasmids containing wild type 3’UTR sequences complementary to RUNX2, which was abolished by 3’UTR mutations. miR-466 reduced RUNX2 regulated downstream molecules such as ANGPT1, ANGPT4, MMP11, Osteopontin (SPP1), and Osteocalcin (OC). MiR-466 also inhibited genes involved in cell proliferation, migration and invasion such as pAKT, FYN and FAK. To determine the biological significance of miR-466 in prostate cancer, we performed parallel experiments in the non-malignant cell line RWPE1 followed by functional assays. Attenuation of miR-466 induced oncogenic characteristics such as increased proliferation, migration and invasion in RWPE1 cells. To examine the in vivo antitumor effects of miR-466, we performed primary and metastatic mouse model experiments. Intra-prostatic implantation of stable cells expressing miR-466 significantly attenuated primary tumor growth. Whereas, bone metastatic dissemination of PC cells was significantly suppressed by intra-cardiac inoculation of stable miR-466 expressing cells compared to control cells in nude mice. We also monitored the overall survival of mice in the metastatic model. Kaplan-Meier survival analysis indicated higher overall survival in the miR-466 group compared to controls.

This is the first study demonstrating that: i) miRNA-466 is downregulated, acts as metastasis suppressor and has diagnostic implications in PC; ii) miR-466 has biological significance in PC as its attenuation induced oncogenic characteristics in normal cells; iii) miR-466 directly targeted RUNX2 and inhibited its downstream genes and iv) stable expression of miR-466 inhibited primary tumor growth and bone metastasis in in vivo models. The use of RNAi is currently being implemented as a gene-specific approach for molecular medicine. By the same principle, it is possible that restoration of silenced miR-466 may lead to down-regulation of target oncogenes thereby contributing to novel therapeutic approaches in the treatment of prostate cancer metastasis.

Citation Format: Shahana Majid, Hanna Nip, Altaf A. Dar, Sharanjot Saini, Varahram Shahryari, Soichiro Yamamura, Yozo Mitsui, Nathan Bucay, Guoren Deng, Rajvir Dahiya, Yuichiro Tanaka. MicroRNA-466 regulates bone metastasis by targeting RUNX2 in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1619.

Loss of miR-200c up-regulates CYP1B1 and confers docetaxel resistance in renal cell carcinoma

Despite high protein expression and enzymatic activity of cytochrome P450 1B1 (CYP1B1) in renal cell cancer (RCC), its functional significance has not been elucidated. Here we explored the functional role and regulatory mechanism of CYP1B1 in RCC. Reduction of CYP1B1 levels fail to prevent in vitro tumorigenicity such as proliferation, apoptosis, and cell cycle progression of RCC cells. Moreover, the expression levels are not associated with tumor type, stage, Fuhrman grade and 5-year survival probability after surgery. Instead, alteration of CYP1B1 expression regulates the chemosensitivity of RCC cells to docetaxel suggesting its critical contribution to the chemoresistance. Additionally, miR-200c, which is significantly down-regulated in RCC regulates CYP1B1 expression and activity. An inverse association was also observed between the expression levels of miR-200c and CYP1B1 protein in RCC tissues. Finally, alteration of miR-200c levels affects the chemosensitivity of RCC cells. Restoration of docetaxel resistance by exogenous expression of CYP1B1 in miR-200c-over-expressing cells indicates that CYP1B1 is a functional target of miR-200c. These results suggest that CYP1B1 up-regulation mediated by low miR-200c is one of the mechanisms underlying resistance of RCC cells to docetaxel. Therefore, expression of CYP1B1 and miR-200c in RCC may be useful as a prediction for docetaxel response.