Prostate Cancer Stem Cells: The Role of CD133

Prostate cancer stem cells (PCSCs), possessing self-renewal properties and resistance to anticancer treatment, are possibly the leading cause of distant metastasis and treatment failure in prostate cancer (PC). CD133 is one of the most well-known and valuable cell surface markers of cancer stem cells (CSCs) in many cancers, including PC. In this article, we focus on reviewing the role of CD133 in PCSC. Any other main stem cell biomarkers in PCSC reported from key publications, as well as about vital research progress of CD133 in CSCs of different cancers, will be selectively reviewed to help us inform the main topic.

Access to urologists for participation in research: An analysis of NCI's Community Oncology Research Program landscape survey

Purpose

Urological cancer clinical trials face accrual challenges, which may stem from structural barriers within cancer programs. We sought to describe the extent to which urology cancer care providers are available within community cancer research programs and explore the role of oncology practice group ownership in their access to urology practices to participate in research.

Materials and methods

We conducted secondary analysis of organizational survey data collected in 2017 among National Cancer Institute Community Oncology Research Program practice groups. We used logistic regression to assess the association of self-reported access to urologists to participate in research and oncology practice group ownership type: independent, payor-provider, health-system, or public ownership.

Results

Of the 209 community oncology practice groups in the analysis sample, 133 (63.6%) had access to urologists for research participation. Ownership was not statistically significantly associated with access to urology practices after controlling for other covariates (p = 0.4). Instead, having a hospital outpatient clinic (p = 0.008) and identifying as a safety-net hospital (p = 0.035) were both positively significantly associated with access to urologists to participate in research.

Conclusions

Two-thirds of community cancer research groups have access to urology. Oncology ownership status was not associated with access to urologists for research. Research groups may need support to increase their capacity to engage non-oncology cancer care providers in research.

Magmas Inhibition in Prostate Cancer: A Novel Target for Treatment-Resistant Disease

Simple Summary

Metastatic and treatment-resistant prostate cancer remains a life-threatening disease despite recent therapeutic advances. Literature suggests that treatment resistance and prostate cancer progression is associated with prostate cancer stem cells. In this study, we evaluated the role of the mitochondria-associated granulocyte–macrophage colony-stimulating factor signaling (Magmas) protein as a molecular target and applied a novel Magmas inhibitor, BT#9, on prostate cancer cells and normal control cells. We found that Magmas was overexpressed in human prostate cancers and its expression was linked to the aggressiveness of the disease. BT#9 downregulated Magmas expression, reduced viability and induced apoptotic cell death in prostate cancer cells. The mechanism of cell death by BT#9 is mainly caspase-independent and via a Reactive Oxygen Species (ROS)-mediated pathway. This is the first study that has evaluated targeting the Magmas protein in prostate cancer and, to our knowledge, the first to elucidate the potential molecular mechanism of BT#9 activity in prostate cancer, including the mode of cell death and the critical role of ROS accumulation. Our work may provide a potential clinical application for a novel prostate cancer treatment that can overcome cancer stem cell and therapeutic resistance.

Abstract

The purpose of our study was to evaluate Magmas as a potential target in prostate cancer. In addition, we evaluated our synthetic Magmas inhibitor (BT#9) effects on prostate cancer and examined the molecular mechanism of BT#9. A cell viability assay showed that treatment with BT#9 caused a significant decrease in the viability of DU145 and PC3 prostate cancer cells with little effect on the viability of WPMY-1 normal prostate cells. Western blot proved that BT#9 downregulated the Magmas protein and caspase-3 activation. Flow cytometry studies demonstrated increased apoptosis and disturbed mitochondrial membrane potential. However, the main mode of cell death was caspase-independent necrosis, which was correlated with the accumulation of mitochondrial and intra-cellular Reactive Oxygen Species (ROS). Taken together, our data suggest Magmas is a potential molecular target for the treatment of prostate cancer and that Magmas inhibition results in ROS-dependent and caspase-independent necrotic cell death.

Safety and efficacy of nivolumab plus ipilimumab in patients with advanced non-clear cell renal cell carcinoma: results from the phase 3b/4 CheckMate 920 trial

BACKGROUND

CheckMate 920 (NCT02982954) is a multicohort, phase 3b/4 clinical trial of nivolumab plus ipilimumab treatment in predominantly US community-based patients with previously untreated advanced renal cell carcinoma (RCC) and clinical features mostly excluded from phase 3 trials. We report safety and efficacy results from the advanced non-clear cell RCC (nccRCC) cohort of CheckMate 920.

METHODS

Patients with previously untreated advanced/metastatic nccRCC, Karnofsky performance status ≥70%, and any International Metastatic Renal Cell Carcinoma Database Consortium risk received up to four doses of nivolumab 3 mg/kg plus ipilimumab 1 mg/kg every 3 weeks followed by nivolumab 480 mg every 4 weeks for ≤2 years or until disease progression/unacceptable toxicity. The primary endpoint was incidence of grade ≥3 immune-mediated adverse events (AEs) within 100 days of last dose of study drug. Key secondary endpoints included objective response rate (ORR), progression-free survival (PFS; both investigator-assessed), time to response (TTR), and duration of response (DOR), all using RECIST V.1.1. Overall survival (OS) was exploratory.

RESULTS

Fifty-two patients with nccRCC (unclassified histology, 42.3%; papillary, 34.6%; chromophobe, 13.5%; translocation-associated, 3.8%; collecting duct, 3.8%; renal medullary, 1.9%) received treatment. With 24.1 months minimum study follow-up, median duration of therapy (range) was 3.5 (0.0-25.8) months for nivolumab and 2.1 (0.0-3.9) months for ipilimumab. Median (range) number of doses received was 4.5 (1-28) for nivolumab and 4.0 (1-4) for ipilimumab. Grade 3-4 immune-mediated AEs were diarrhea/colitis (7.7%), rash (5.8%), nephritis and renal dysfunction (3.8%), hepatitis (1.9%), adrenal insufficiency (1.9%), and hypophysitis (1.9%). No grade 5 immune-mediated AEs occurred. ORR (n=46) was 19.6% (95% CI 9.4 to 33.9). Two patients achieved complete response (papillary, n=1; unclassified, n=1), seven achieved partial response (papillary, n=4; unclassified, n=3), and 17 had stable disease. Median TTR was 2.8 (range 2.1-14.8) months. Median DOR was not reached (range 0.0+-27.8+); eight of nine responders remain without reported progression. Median PFS (n=52) was 3.7 (95% CI 2.7 to 4.6) months. Median OS (n=52) was 21.2 (95% CI 16.6 to not estimable) months.

CONCLUSIONS

Nivolumab plus ipilimumab for previously untreated advanced nccRCC showed no new safety signals and encouraging antitumor activity.

TRIAL REGISTRATION NUMBER

NCT02982954.

Safety and Efficacy of Nivolumab in Patients With Advanced Clear Cell Renal Cell Carcinoma: Results From the Phase IIIb/IV CheckMate 374 Study

BACKGROUND

The open-label, phase IIIb/IV CheckMate 374 study (NCT02596035) was conducted to validate the safety and efficacy of flat-dose nivolumab monotherapy 240 mg every 2 weeks (Q2W) in previously treated advanced/metastatic renal cell carcinoma (RCC). Three cohorts included patients with predominantly clear cell histology, non-clear cell histologies, or brain metastases. We report safety and efficacy from the CheckMate 374 advanced clear cell RCC (ccRCC) cohort.

PATIENTS AND METHODS

Eligible patients received prior treatment regimens (1-2 antiangiogenic; 0-3 systemic) with progression on/after last treatment and ≤ 6 months of enrollment. Patients received nivolumab 240 mg Q2W for ≤ 24 months or until confirmed progression/unacceptable toxicity. The primary endpoint was incidence of high-grade (grade 3-5) immune-mediated adverse events (IMAEs). Exploratory endpoints included objective response rate, progression-free survival, and overall survival.

RESULTS

Ninety-seven patients had advanced predominantly ccRCC; 75.3% received only 1 prior systemic regimen in the advanced/metastatic setting. After a median follow-up of 17 months (range, 0.4-26.9 months), no grade 5 IMAEs occurred, and 9.3% of patients reported grade 3/4 IMAEs (hepatitis, 4.1%; diabetes mellitus, 2.1%; nephritis and renal dysfunction, 1.0%; rash, 1.0%; adrenal insufficiency, 1.0%). The objective response rate was 22.7% (95% confidence interval [CI], 14.8%-32.3%). Three patients had a complete response; 19 had partial responses. The median progression-free survival was 3.6 months (95% CI, 2.0-5.5 months). The median overall survival was 21.8 months (95% CI, 17.4 months to not estimable).

CONCLUSIONS

This study validates the safety and efficacy of nivolumab 240 mg Q2W flat-dose monotherapy for previously treated advanced ccRCC and adds to previous safety and efficacy data using the 3 mg/kg Q2W dose.

Safety and Efficacy of Nivolumab in Patients With Advanced Non-Clear Cell Renal Cell Carcinoma: Results From the Phase IIIb/IV CheckMate 374 Study

BACKGROUND

The open-label phase IIIb/IV CheckMate 374 study (NCT02596035) was conducted to validate the safety and efficacy of flat-dose nivolumab 240 mg every 2 weeks (Q2W) in previously treated advanced/metastatic renal cell carcinoma. Three cohorts included patients with predominantly clear cell histology, non-clear cell histologies, or brain metastases. We report safety and efficacy from the advanced non-clear cell RCC (nccRCC) cohort of CheckMate 374.

METHODS

Eligible patients received 0 to 3 prior systemic therapies. Patients received nivolumab 240 mg Q2W for ≤24 months or until confirmed progression or unacceptable toxicity. The primary endpoint was incidence of high-grade (grade 3-5) immune-mediated adverse events (IMAEs). Exploratory endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Forty-four patients had advanced nccRCC (papillary [n = 24], chromophobe [n = 7], unclassified [n = 8], other [n = 5]); 34.1% received ≥1 prior systemic regimen in the advanced/metastatic setting. With median follow-up of 11 (range, 0.4-27) months, no all-cause grade 3-5 IMAEs or treatment-related grade 5 adverse events were reported. ORR was 13.6% (95% confidence interval [CI], 5.2-27.4), with 1 complete response (chromophobe) and 5 partial responses (papillary [n = 2], chromophobe [n = 1], collecting duct [n = 1], and unclassified [n = 1] histology). Median PFS was 2.2 months (95% CI, 1.8-5.4). Median OS was 16.3 months (95% CI, 9.2-not estimable).

CONCLUSIONS

Safety of flat-dose nivolumab 240 mg Q2W was consistent with previous results. Clinically meaningful efficacy was observed with responses in several histologies, supporting nivolumab as a treatment option for patients with advanced nccRCC, a patient population with high unmet need.

Effect of a Behavioral Intervention to Increase Vegetable Consumption on Cancer Progression Among Men With Early-Stage Prostate Cancer: The MEAL Randomized Clinical Trial

IMPORTANCE

Guidelines endorsing vegetable-enriched diets to improve outcomes for prostate cancer survivors are based on expert opinion, preclinical studies, and observational data.

OBJECTIVE

To determine the effect of a behavioral intervention that increased vegetable intake on cancer progression in men with early-stage prostate cancer.

DESIGN, SETTING, AND PARTICIPANTS

The Men's Eating and Living (MEAL) Study (CALGB 70807 [Alliance]) was a randomized clinical trial conducted at 91 US urology and medical oncology clinics that enrolled 478 men aged 50 to 80 years with biopsy-proven prostate adenocarcinoma (International Society of Urological Pathology grade group = 1 in those <70 years and ≤2 in those ≥70 years), stage cT2a or less, and serum prostate-specific antigen (PSA) level less than 10 ng/mL. Enrollment occurred from January 2011 to August 2015; 24-month follow-up occurred from January 2013 to August 2017.

INTERVENTIONS

Patients were randomized to a counseling behavioral intervention by telephone promoting consumption of 7 or more daily vegetable servings (MEAL intervention; n = 237) or a control group, which received written information about diet and prostate cancer (n = 241).

MAIN OUTCOMES AND MEASURES

The primary outcome was time to progression; progression was defined as PSA level of 10 ng/mL or greater, PSA doubling time of less than 3 years, or upgrading (defined as increase in tumor volume or grade) on follow-up prostate biopsy.

RESULTS

Among 478 patients randomized (mean [SD] age, 64 [7] years; mean [SD] PSA level, 4.9 [2.1] ng/mL), 443 eligible patients (93%) were included in the primary analysis. There were 245 progression events (intervention: 124; control: 121). There were no significant differences in time to progression (unadjusted hazards ratio, 0.96 [95% CI, 0.75 to 1.24]; adjusted hazard ratio, 0.97 [95% CI, 0.76 to 1.25]). The 24-month Kaplan-Meier progression-free percentages were 43.5% [95% CI, 36.5% to 50.6%] and 41.4% [95% CI, 34.3% to 48.7%] for the intervention and control groups, respectively (difference, 2.1% [95% CI, -8.1% to 12.2%]).

CONCLUSIONS AND RELEVANCE

Among men with early-stage prostate cancer managed with active surveillance, a behavioral intervention that increased vegetable consumption did not significantly reduce the risk of prostate cancer progression. The findings do not support use of this intervention to decrease prostate cancer progression in this population, although the study may have been underpowered to identify a clinically important difference.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01238172.

Emblica officinalis extract downregulates pro-angiogenic molecules via upregulation of cellular and exosomal miR-375 in human ovarian cancer cells

Ovarian cancer (OC) is highly resistant to current treatment strategies based on a combination of surgery, chemotherapy and radiation therapy. We have recently demonstrated the anti-neoplastic effect of Amla extract (Emblica officinalis, AE) on OC cells in vitro and in vivo. We hypothesized that AE attenuates growth of OC through microRNA (miR)-regulated mechanism(s). The inhibitory effect of AE on proliferation, migration and invasiveness (P≤0.001) of SKOV3 cells and >90% attenuation of tumor growth in a xenograft mouse model suggested multiple targets. RT-qPCR analysis of microRNAs associated with OC showed a >2,000-fold increase in the expression of miR-375 in AE-treated SKOV3 cells that was blocked by an exogenous miR-375 inhibitor (P≤0.001). AE also decreased the gene and protein expression of IGF1R, a target of miR-375 (P≤0.001), and SNAIL1 (P≤0.002), an EMT-associated transcription factor that represses E-cadherin expression (P≤0.003). AE increased E-cadherin expression (P≤0.001). Treatment of SKOV3 cells with AE resulted in increased miR-375 in exosomes in the medium (P≤0.01). Finally, AE significantly decreased the expression of IGF1R and SNAIL1 proteins during attenuation of SKOV3-derived xenograft tumor. Together, these results show that AE modulates cancer cells and the tumor microenvironment via activation of miR-375 and by targeting IGF1R and SNAIL1 in OC cells.

Metastatic prostate cancer in the modern era of PSA screening

Introduction

To characterize initial presentation and PSA screening status in a contemporary cohort of men treated for metastatic prostate cancer at our institution.

Materials and methods

We reviewed records of 160 men treated for metastatic prostate cancer between 2008-2014 and assessed initial presentation, categorizing patients into four groups. Groups 1 and 2 presented with localized disease and received treatment. These men suffered biochemical recurrence late (>1 year) or earlier (<1 year), respectively, and developed metastases. Groups 3 and 4 had asymptomatic and symptomatic metastases at the outset of their diagnosis. Patients with a first PSA at age 55 or younger were considered to have guideline-directed screening.

Results

Complete records were available on 157 men for initial presentation and 155 men for PSA screening. Groups 1, 2, 3 and 4 included 27 (17%), 7 (5%), 69 (44%) and 54 (34%) patients, respectively. Twenty (13%) patients received guideline-directed PSA screening, 5/155 (3%) patients presented with metastases prior to age 55 with their first PSA, and 130/155 (84%) had their first PSA after age 55, of which 122/130 (94%) had metastasis at the time of diagnosis.

Conclusion

Despite widespread screening, most men treated for metastatic prostate cancer at our institution presented with metastases rather than progressed after definitive treatment. Furthermore, 25 (16%) patients received guideline-directed PSA screening at or before age 55. These data highlight that, despite mass screening efforts, patients treated for incurable disease at our institution may not have been a result of a failed screening test, but a failure to be screened.

Vitamin D Impacts the Expression of Runx2 Target Genes and Modulates Inflammation, Oxidative Stress and Membrane Vesicle Biogenesis Gene Networks in 143B Osteosarcoma Cells

Osteosarcoma (OS) is an aggressive malignancy of bone affecting children, adolescents and young adults. Understanding vitamin D metabolism and vitamin D regulated genes in OS is an important aspect of vitamin D/cancer paradigm, and in evaluating vitamin D as adjuvant therapy for human OS. Vitamin D treatment of 143B OS cells induced significant and novel changes in the expression of genes that regulate: (a) inflammation and immunity; (b) formation of reactive oxygen species, metabolism of cyclic nucleotides, sterols, vitamins and mineral (calcium), quantity of gap junctions and skeletogenesis; (c) bone mineral density; and (d) cell viability of skeletal cells, aggregation of bone cancer cells and exocytosis of secretory vesicles. Ingenuity pathway analysis revealed significant reduction in Runx2 target genes such as fibroblast growth factor -1, -12 (FGF1 and FGF12), bone morphogenetic factor-1 (BMP1), SWI/SNF related, matrix associated actin dependent regulator of chromatin subfamily a, member 4 (SMARCA4), Matrix extracellular phosphoglycoprotein (MEPE), Integrin, β4 (ITGBP4), Matrix Metalloproteinase -1, -28 (MMP1 and MMP28), and signal transducer and activator of transcription-4 (STAT4) in vitamin D treated 143B OS cells. These genes interact with the inflammation, oxidative stress and membrane vesicle biogenesis gene networks. Vitamin D not only inhibited the expression of Runx2 target genes MMP1, MMP28 and kallikrein related peptidase-7 (KLK7), but also migration and invasion of 143B OS cells. Vitamin D regulated Runx2 target genes or their products represent potential therapeutic targets and laboratory biomarkers for applications in translational oncology.

Impact of Sequencing Targeted Therapies With High-dose Interleukin-2 Immunotherapy: An Analysis of Outcome and Survival of Patients With Metastatic Renal Cell Carcinoma From an On-going Observational IL-2 Clinical Trial: PROCLAIMSM

BACKGROUND

This analysis describes the outcome for patients who received targeted therapy (TT) prior to or following high-dose interleukin-2 (HD IL-2).

PATIENTS AND METHODS

Patients with renal cell carcinoma (n = 352) receiving HD IL-2 were enrolled in Proleukin^R Observational Study to Evaluate the Treatment Patterns and Clinical Response in Malignancy (PROCLAIM^SM) beginning in 2011. Statistical analyses were performed using datasets as of September 24, 2015.

RESULTS

Overall, there were 4% complete response (CR), 13% partial response (PR), 39% stable disease (SD), and 43% progressive disease (PD) with HD IL-2. The median overall survival (mOS) was not reached in patients with CR, PR, or SD, and was 15.5 months in patients with PD (median follow-up, 21 months). Sixty-one patients had prior TT before HD IL-2 with an overall response rate (ORR) to HD IL-2 of 19% (1 CR, 9 PR) and an mOS of 22.1 months. One hundred forty-nine patients received TT only after HD IL-2 with an mOS of 35.5 months. One hundred forty-two patients had no TT before or after HD IL-2, and mOS was not reached. The mOS was 8.5 months in PD patients who received HD IL-2 without follow-on TT and 29.7 months in PD patients who received follow-on TT after HD IL-2.

CONCLUSIONS

HD IL-2 as sole front-line therapy, in the absence of added TT, shows extended clinical benefit (CR, PR, and SD). Patients with PD after HD IL-2 appear to benefit from follow-on TT. Patients who progressed on TT and received follow-on HD IL-2 experienced major clinical benefit. HD IL-2 therapy should be considered in eligible patients.

Abstract 4528: Comparison of anti-proliferation activity of BEZ 235, a multi-step inhibitor of mTOR pathway, vs. BKM120, a pan PI3K inhibitor, in lung cancer cell lines (LCCL)

Background: PI3K/AKT/mTOR(Mammalian target of rapamycin) signal transduction pathway is over-activated in many cancers including lung cancers. The activation of cell surface receptors i.e.EGFR (Epidermal Growth Factor Receptor) signals through PI3K/AKT/mTOR pathway which then results in increase cell proliferation, angiogenesis and anti-apoptosis process. BEZ 235 is a multi-step inhibitor of PI3K and mTORC 1 / 2. BKM 120 is a novel pan class I PI3K inhibitor of all class I PI3K isoforms (α, β, Υ, δ). Inhibition of multiple steps of PI3K/AKT/mTOR pathway would be advantageous and could yield higher activity and overcome over activation of PI3K/AKT, a potential mechanism of resistance to mTOR inhibitors. Docetaxel (D) is an approved agent used in the treatment of lung cancer. We previously demonstrated that the sequence of D followed by mTOR inhibitor temsirolimus (T) in lung cancer cell lines (LCCL) had increased suppression of cell proliferation as compared to reverse sequence of T→D due to suppression of over-activation of PI3K/AKT resistance mechanism. We studied the anti-proliferation effect of each compound in LCCL and also compared the activity of sequential docetaxel followed by BKM 120 vs. D followed by BEK235. Methods: Adenocarcinoma LCCL H2122 and A549 were treated with increasing concentrations of BEZ 235 (50nM, 75 nM, 100 nM) and BKM 120 at same concentrations. Both agents were provided by Novartis.We assessed the cell proliferation by optical density. In the sequential treatment study, we incubated LCCL with D 100nM for 24h then added BKM 120 or BEZ235 at 50nM, 75nM and 100nM. We then assessed the anti-proliferation effect at 48h and 72h.

Results: BEZ 235 single had greater inhibitory effect in LCCL proliferation as compared to BKM120. The sequential treatment of D followed by BEZ235 or BKM120 did not yield higher anti-proliferation effect compared to single agent treatment in both LCCL.

Conclusion: Single agent BEZ235 had greater anti-proliferation effect than BKM120 in both LCCL. The sequential treatment of D followed by BEZ235 or BKM120 did not lead to increased anti-proliferation effect. The potential explanation of lack of synergistic effect may due to suppression of PI3K by pretreatment with D.

Note: This abstract was not presented at the meeting.

Citation Format: Chao H. Huang, Christopher Beaudoin, Peter Van Veldhuizen, Faris Farassati. Comparison of anti-proliferation activity of BEZ 235, a multi-step inhibitor of mTOR pathway, vs. BKM120, a pan PI3K inhibitor, in lung cancer cell lines (LCCL). [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4528. doi:10.1158/1538-7445.AM2014-4528

A potential regulatory loop between Lin28B:miR‑212 in androgen-independent prostate cancer

Lin28 is a family of RNA binding proteins and microRNA regulators. Two members of this family have been identified: Lin28A and Lin28B, which are encoded by genes localized in different chromosomes but share a high degree of sequence identity. The role of Lin28B in androgen-independent prostate cancer (AIPC) is not well understood. Lin28B is expressed in all grades of prostatic carcinomas and prostate cancer cell lines, but not in normal prostate tissue. In this study we found that Lin28B co-localized in the nucleus and cytoplasm of the DU145 AIPC. The expression of Lin28B protein positively correlated with the expression of the c-Myc protein in the prostate cancer cell lines and silencing of Lin28B also correlated with a lower expression of the c-Myc protein, but not with the downregulation of c-Myc messenger RNA (mRNA) in the DU145 AIPC cells. We hypothesized that Lin28B regulates the expression of c-Myc protein by altering intermediate c-Myc suppressors. Therefore, a microRNA profile of DU145 cells was performed after Lin28B siRNA silencing. Nineteen microRNAs were upregulated and eleven microRNAs were downregulated. The most upregulated microRNAs were miR-212 and miR-2278. Prior reports have found that miR-212 is suppressed in prostate cancer. We then ran TargetScan software to find potential target mRNAs of miR-212 and miR-2278, and it predicted Lin28B mRNA as a potential target of miR-212, but not miR-2278. TargetScan also predicted that c-Myc mRNA is not a potential target of miR-212 or miR-2278. These observations suggest that Lin28B:miR-212 may work as a regulatory loop in androgen-independent prostate cancer. Furthermore, we report a predictive 2-fold symmetric model generated by the superposition of the Lin28A structure onto the I-TASSER model of Lin28B. This structural model of Lin28B suggests that it shows unique microRNA binding characteristics. Thus, if Lin28B were to bind miRNAs in a manner similar to Lin28A, conformational changes would be necessary to prevent steric clashes in the C-terminal and linker regions between the CSD and ZNF domains.

Leukemoid reaction and autocrine growth of bladder cancer induced by paraneoplastic production of granulocyte colony-stimulating factor--a potential neoplastic marker: a case report and review of the literature

Introduction

Granulocyte colony-stimulating factor produced by nonhematopoietic malignant cells is able to induce a leukemoid reaction by excessive stimulation of leukocyte production. Expression of granulocyte colony-stimulating factor and its functional receptors have been confirmed in bladder cancer cells. In vitro studies have demonstrated that granulocyte colony-stimulating factor/receptor exhibits a high affinity binding and this biological axis increases proliferation of the carcinoma. Urothelial carcinoma of the bladder is rarely associated with a leukemoid reaction and autocrine growth induced by paraneoplastic production of granulocyte colony-stimulating factor. In the world literature, there have been less than 35 cases reported in the last 35 years. The clinicopathological aspects, biology, prognosis and management of granulocyte colony-stimulating factor-secreting bladder cancers are poorly understood.

Case presentation

A 39-year-old Caucasian woman with an invasive high-grade urothelial carcinoma presented with hematuria and low-grade fevers. Laboratory tests revealed an elevated white blood cell count and absolute neutrophil count and an elevated 24-hour urine protein. Upon further evaluation she was found to have locally advanced high-grade urothelial carcinoma without nodal or distant metastasis. Her serum granulocyte colony-stimulating factor level was 10 times the normal limit. This led to the diagnosis of a paraneoplastic leukemoid reaction. Her white blood cell count immediately normalized after cystectomy but increased in concordance with recurrence of her disease. Unfortunately, she rapidly progressed and expired within 10 months from the time of first diagnosis.

Conclusions

This is one of the few cases reported that illustrates the existence of a distinct and highly aggressive subtype of bladder cancer which secretes granulocyte colony-stimulating factor. Patients presenting with a leukemoid reaction should be tested for granulocyte colony-stimulating factor/receptor biological axis. Moreover, granulocyte colony-stimulating factor could be a potential neoplastic marker as it can follow the clinical course of the underlying tumor and thus be useful for monitoring its evolution. Neoadjuvant chemotherapy should be considered in these patients due to the aggressive nature of these tumors. With a better understanding of the biology, this autocrine growth signal could be a potential target for therapy in future.

An open-label study to investigate the cardiac safety profile of cabazitaxel in patients with advanced solid tumors

PURPOSE

This study assessed the cardiovascular safety of cabazitaxel, based on thorough evaluation of QT and non-QT variables, and the relationship between pharmacokinetic and pharmacodynamic electrocardiographic (ECG) profiles and the occurrence of Grade ≥3 cardiovascular adverse events.

METHODS

Patients with advanced solid tumors were treated with cabazitaxel 25 mg/m(2) every 3 weeks. Digital ECG recordings were obtained during Cycle 1 over 24 h after dosing. The primary end point was effect of cabazitaxel on QT interval corrected by the Fridericia formula (QTcF). Secondary end points were additional ECG parameters (QT, PR and QRS intervals, and heart rate), plasma pharmacokinetics of cabazitaxel and overall clinical safety.

RESULTS

The pharmacodynamic (ECG) population included 94 patients. In 63 patients with a full 24-h ECG evaluation, the maximum upper bound of 90 % confidence interval (CI) for mean QTcF change from baseline was 7.46 ms (mean 4.8 ms), occurring at 1 h 30 min post-infusion. The slope of QTcF change from baseline versus cabazitaxel concentration was slightly negative (-0.012 [95 % CI -0.017; -0.008], equivalent to a 1.2 ms decrease per 100 ng/mL increase in cabazitaxel concentration). For non-QT variables, no effect was noted. No Grade ≥3 cardiac adverse events were observed; Grade ≥3 hypotension and lymphocele occurred in two patients and one patient, respectively.

CONCLUSION

These results suggest that cabazitaxel has no clinically significant cardiovascular adverse effects in patients with advanced solid tumors.

Retinoic acid signaling pathways in development and diseases

Retinoids comprise a group of compounds each composed of three basic parts: a trimethylated cyclohexene ring that is a bulky hydrophobic group, a conjugated tetraene side chain that functions as a linker unit, and a polar carbon-oxygen functional group. Biochemical conversion of carotenoid or other retinoids to retinoic acid (RA) is essential for normal regulation of a wide range of biological processes including development, differentiation, proliferation, and apoptosis. Retinoids regulate various physiological outputs by binding to nuclear receptors called retinoic acid receptors (RARs) and retinoid X receptors (RXRs), which themselves are DNA-binding transcriptional regulators. The functional response of RA and their receptors are modulated by a host of coactivators and corepressors. Retinoids are essential in the development and function of several organ systems; however, deregulated retinoid signaling can contribute to serious diseases. Several natural and synthetic retinoids are in clinical use or undergoing trials for treating specific diseases including cancer. In this review, we provide a broad overview on the importance of retinoids in development and various diseases, highlighting various retinoids in the drug discovery process, ranging all the way from retinoid chemistry to clinical uses and imaging.

Denosumab and bone metastasis-free survival in men with nonmetastatic castration-resistant prostate cancer: exploratory analyses by baseline prostate-specific antigen doubling time

PURPOSE

Denosumab, an anti-RANK ligand monoclonal antibody, significantly increases bone metastasis-free survival (BMFS; hazard ratio [HR], 0.85; P = .028) and delays time to first bone metastasis in men with nonmetastatic castration-resistant prostate cancer (CRPC) and baseline prostate-specific antigen (PSA) ≥ 8.0 ng/mL and/or PSA doubling time (PSADT) ≤ 10.0 months. To identify men at greatest risk for bone metastasis or death, we evaluated relationships between PSA and PSADT with BMFS in the placebo group and the efficacy and safety of denosumab in men with PSADT ≤ 10, ≤ 6, and ≤ 4 months.

PATIENTS AND METHODS

A total of 1,432 men with nonmetastatic CRPC were randomly assigned 1:1 to monthly subcutaneous denosumab 120 mg or placebo. Enrollment began February 2006; primary analysis cutoff was July 2010, when approximately 660 men were anticipated to have developed bone metastases or died.

RESULTS

In the placebo group, shorter BMFS was observed as PSADT decreased below 8 months. In analyses by shorter baseline PSADT, denosumab consistently increased BMFS by a median of 6.0, 7.2, and 7.5 months among men with PSADT ≤ 10 (HR, 0.84; P = .042), ≤ 6 (HR, 0.77; P = .006), and ≤ 4 months (HR, 0.71; P = .004), respectively. Denosumab also consistently increased time to bone metastasis by PSADT subset. No difference in survival was observed between treatment groups for the overall study population or PSADT subsets.

CONCLUSION

Patients with shorter PSADT are at greater risk for bone metastasis or death. Denosumab consistently improves BMFS in men with shorter PSADT and seems to have the greatest treatment effects in men at high risk for progression.

Short-term soy isoflavone intervention in patients with localized prostate cancer: a randomized, double-blind, placebo-controlled trial

PURPOSE

We describe the effects of soy isoflavone consumption on prostate specific antigen (PSA), hormone levels, total cholesterol, and apoptosis in men with localized prostate cancer.

METHODOLOGY/PRINCIPAL FINDINGS

We conducted a double-blinded, randomized, placebo-controlled trial to examine the effect of soy isoflavone capsules (80 mg/d of total isoflavones, 51 mg/d aglucon units) on serum and tissue biomarkers in patients with localized prostate cancer. Eighty-six men were randomized to treatment with isoflavones (n=42) or placebo (n=44) for up to six weeks prior to scheduled prostatectomy. We performed microarray analysis using a targeted cell cycle regulation and apoptosis gene chip (GEArrayTM). Changes in serum total testosterone, free testosterone, total estrogen, estradiol, PSA, and total cholesterol were analyzed at baseline, mid-point, and at the time of radical prostatectomy. In this preliminary analysis, 12 genes involved in cell cycle control and 9 genes involved in apoptosis were down-regulated in the treatment tumor tissues versus the placebo control. Changes in serum total testosterone, free testosterone, total estrogen, estradiol, PSA, and total cholesterol in the isoflavone-treated group compared to men receiving placebo were not statistically significant.

CONCLUSIONS/SIGNIFICANCE

These data suggest that short-term intake of soy isoflavones did not affect serum hormone levels, total cholesterol, or PSA.

TRIAL REGISTRATION

ClinicalTrials.gov NCT00255125.

A novel three-dimensional stromal-based model for in vitro chemotherapy sensitivity testing of leukemia cells

The disparate response of leukemia cells to chemotherapy in vivo, compared to in vitro, is partly related to the interaction of leukemic cells and the three-dimensional bone marrow stromal microenvironment. We investigated the effects of chemotherapy agents on leukemic cell lines co-cultured with human bone marrow mesenchymal stem cells (hu-BM-MSCs) in a three-dimensional model (3D). Comparison was made to leukemic cells treated in suspension, or grown on a hu-BM-MSC monolayer (2D conditions). We demonstrated that leukemic cells cultured in 3D were more resistant to drug-induced apoptosis compared to cells cultured in 2D or in suspension. We also demonstrated significant differences in leukemic cell response to chemotherapy using different leukemic cell lines cultured in 3D. We suggest that the differential responses to chemotherapy in 3D may be related to the expression of N-cadherin in the co-culture system. This unique model provides an opportunity to study leukemic cell responses to chemotherapy in 3D.

The matricellular protein CCN1/Cyr61 is a critical regulator of Sonic Hedgehog in pancreatic carcinogenesis

CCN1 is a matricellular protein and a member of the CCN family of growth factors. CCN1 is associated with the development of various cancers including pancreatic ductal adenocarcinoma (PDAC). Our recent studies found that CCN1 plays a critical role in pancreatic carcinogenesis through the induction of EMT and stemness. CCN1 mRNA and protein were detected in the early precursor lesions, and their expression intensified with disease progression. However, biochemical activity and the molecular targets of CCN1 in pancreatic cancer cells are unknown. Here we show that CCN1 regulates the Sonic Hedgehog (SHh) signaling pathway, which is associated with the PDAC progression and poor prognosis. SHh regulation by CCN1 in pancreatic cancer cells is mediated through the active Notch-1. Notably, active Notch-1is recruited by CCN1 in these cells via the inhibition of proteasomal degradation results in stabilization of the receptor. We find that CCN1-induced activation of SHh signaling might be necessary for CCN1-dependent in vitro pancreatic cancer cell migration and tumorigenicity of the side population of pancreatic cancer cells (cancer stem cells) in a xenograft in nude mice. Moreover, the functional role of CCN1 could be mediated through the interaction with the αvβ3 integrin receptor. These extensive studies propose that targeting CCN1 can provide a new treatment option for patients with pancreatic cancer since blocking CCN1 simultaneously blocks two critical pathways (i.e. SHh and Notch1) associated with the development of the disease as well as drug resistance.

Effect of denosumab on prolonging bone-metastasis free survival (BMFS) in men with nonmetastatic castrate-resistant prostate cancer (CRPC) presenting with aggressive PSA kinetics

4510

Background: Denosumab, an anti-RANK-ligand monoclonal antibody, has been shown to prolong BMFS by a median 4.2 months and with a 15% risk reduction vs. placebo in men with non-metastatic CRPC and baseline PSA value ≥ 8.0 ng/mL and/or PSA doubling time (PSADT) ≤10.0 months. To determine the efficacy of denosumab in men at greatest risk for bone metastases, we evaluated BMFS in a subset of men with PSADT ≤6 months (previously reported in Smith MR, et al: J Clin Oncol. 23:2918-2925, 2005). Methods: 1,432 men with non-metastatic CRPC (baseline medians: PSA: 12.3 ng/mL, PSADT: 5.1 months, ADT duration: 47.1 months) were randomized 1:1 to receive monthly subcutaneous denosumab 120 mg or placebo. The first patient enrolled February 2006; primary analysis cut-off was July 2010, when >660 men had developed bone metastasis or died. The primary endpoint was BMFS (time to first bone metastasis or death from any cause). BMFS results are presented for men with baseline PSADT ≤6 months. Results: Median BMFS in the placebo group of men with PSADT ≤6 months was 6.5 months shorter than for the placebo group in the full population (18.7 months vs. 25.2 months), indicating that these men are at particularly high risk. In this group of men with PSADT ≤6 months, denosumab prolonged BMFS by a median of 7.2 months and with a 23% reduction in risk compared with placebo (Table). Conclusions: Patients with shortened PSADT are at higher risk of developing bone metastasis and denosumab is markedly effective at prolonging BMFS in this subset of patients. [Table: see text]

Inhibition of RalA signaling pathway in treatment of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and relatively resistant to chemotherapy. The most prevalent molecular abnormality in NSCLC is the overactivation of K-Ras proto-oncogene; therefore, elucidating down-stream Ras signaling in NSCLC is significantly important in developing novel therapies against this malignancy. Our work indicates that RalA, an important effector of Ras, is activated in NSCLC cell lines. While RalA was also overactivated in fetal human broncho-epithelial cells, RalBP1 (Ral binding protein-1), an important down-stream effector of RalA, was expressed at higher levels in cancer cell lines. Aurora kinase-A (AKA), an upstream activator of RalA, was also found to be active only in malignant cells. The outcome of inhibition of RalA (by gene specific silencing using a lentivirus) on the malignant phenotype of A549 cells was also studied. While proliferation and invasiveness of A549 cells were reduced upon silencing RalA, apoptosis and necrosis were elevated in such conditions. Additionally, the in vivo tumorigenesis of A549 cells was reduced upon partial inhibition of RalA and AKA using pharmacological inhibitors. Finally, we were interested in evaluating the level of active RalA in the fraction of NSCLC cells expressing cancer stem cell markers. For this purpose cells with increased expression of CD44 were separated from A549 cells and compared with cells with low level of expression of this marker and an unsorted population. A significant enhancement of RalA activation in high CD44+ cells was found as potential evidence for involvement of RalA signaling in initiation of the neoplastic procedure and an important contributor for tumor maintenance in NSCLC. Further studies can reveal therapeutic, preventive and diagnostic value of RalA pathway in this deadly disease.

Dual antigen target-based immunotherapy for prostate cancer eliminates the growth of established tumors in mice

AIMS

We have previously shown that immunization with an adenovirus vector carrying an individual antigen induces antigen-specific CD8 T cells actively engaged in the destruction of tumor cells expressing the cognate antigen. In order to expand the range of antitumor responses beyond an individual antigen, we designed a recombinant adenovirus type 5 (rAd5) carrying a fusion construct of two full-length antigens. We used this adenovirus vector to test the concept that multiantigenic effector T cells could be generated simultaneously following a single immunization.

METHOD

To perform the rAd5 constructs, we selected a combination of prostate-specific antigen (PSA) and prostate stem cell antigen (PSCA) genes based on their restricted distribution within the prostate tissue and their association with the development and progression of prostate cancer.

RESULTS

Immunization of mice with rAd5 vector carrying a fusion construct of PSA and PSCA (Ad5-PSA/PSCA) simultaneously induced the expansion of anti-PSA and anti-PSCA CD8 T cells, as measured by intracellular cytokine staining for IFN-γ. The antigen-specific T-cell responses that developed were efficient in eliminating the target cells expressing cognate antigens measured by an in vivo cytotoxic T-cell assay. The in vivo tumor growth study showed that immunization of mice with Ad5-PSA/PSCA vaccine induced strong antitumor immunity when challenged with mouse prostate tumor cell lines (RM11) expressing human PSA (RM11/PSA). To further analyze the impact on therapeutic efficacy of Ad5-PSA/PSCA vaccine against the tumor cells expressing PSA and PSCA (RM11-PSA/PSCA) antigens, we injected mice with Ad5-PSA/PSCA vaccine. The vaccine inhibited the growth of established tumors with 80% of the mice becoming tumor free. These data provide useful information that antigen-specific effector T cells can be generated simultaneously and that their additive antitumor effect has the potential to eliminate the growth of established tumors. Therefore, the immunotherapy approach of using the simultaneous targeting of dual antigens associated with prostate cancer may have important implications for human clinical trials.

Prostate imaging modalities that can be used for complementary and alternative medicine clinical studies

This article provides an overview of imaging modalities that aid in diagnosing, staging, and assessing therapeutic response in prostate cancer. Prostate cancer is the second most common type of cancer in American men and the second leading cause of cancer death among men. Prostate cancer is difficult to diagnose in early stages, and advanced disease often recurs after treatment. To localize sites of recurrence many imaging modalities have been used with varying success. This article presents case studies of PET scanning using carbon 11 acetate and discusses intravenously infused ascorbate, a complementary and alternative medicine therapy for prostate cancer.

Abstract 5397: Crocetin, a carotenoid compound derived from Saffron, enhances antitumor effects of paclitaxol and cisplatin in pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer deaths in the United States and no significant treatment is at present available. Although there are an increasing number of therapeutic options available for patients with advanced disease, their efficacy is time limited and non-curative. Presently approximately 50-60% of cancer patients in the United States utilize therapies derived from plants, herbs, flowers, or nutrients (complementary and alternative medicine [CAM]), exclusively or concurrently with their traditional therapies such as chemotherapy or radiation therapy. One such CAM therapy is “crocetin”, a carotenoid compound isolated from the saffron plant. Recent studies demonstrated that crocetin has a significant antitumorigenic effect in both in vitro and in vivo on pancreatic cancer. Two conventional chemotherapeutic agents, paclitaxol (a microtubule-targeted agent) and cisplatin (a platinum based anticancer drug binds to DNA), have been demonstrated significant reduction of growth and proliferation in pancreatic cancer. Therefore, the aim of the series of experiments was to determine whether crocetin enhances paclitaxol or cisplatin induced proliferation in pancreatic cancer. MIA-PaCa-2 and BxPC3 cells were treated with crocetin and paclitaxol or cisplatin together at different doses and a proliferation assay was utilized using Click-it Edu flurorometric assay. Paclitaxol or cisplatin alone at higher doses (50-100nM) inhibited proliferation in both MIA PaCa2 and BxPC3 cells but crocetin (200μM) in combination of paclitaxol or cisplatin showed significant additive effect even at lower doses (10 and 25nM) of paclitaxol or cisplatin. The combinational effect is more pronounced in BxPC3 cells. Paclitaxol or cisplatin alone at higher doses (50-100nM) stimulated apoptosis using Deadend flurorometric TUNEL apoptosis assay in MIA PaCa2 and BxPC3 cells and apoptosis is more pronounced at lower doses in combination with crocetin. This study indicated that crocetin in combination with lower doses of paclitaxol or cisplatin inhibited proliferation and stimulated apoptosis in pancreatic cancer. The antitumorigenic effect is more pronounced in BxPC3 cells and paclitaxol is more effective than cisplatin at lower doses in combination with crocetin.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5397.

Phase II study of darinaparsin in patients with advanced hepatocellular carcinoma

BACKGROUND

Darinaparsin is a novel organic arsenic that reaches higher intracellular concentration with decreased toxicity compared to inorganic arsenic. We conducted a multi-center phase II study with darinaparsin in patients with advanced HCC.

METHODS

Eligibility criteria included unresectable or metastatic measurable HCC, up to two prior systemic treatments, ECOG performance status < or = 2, Child Pugh Class A or B and adequate organ functions. Darinaparsin was administered at 420 mg/m(2) intravenously, twice weekly at least 72 h apart for 3 weeks in a 4-week cycle. The primary end point was response rate. A Simon two-stage design was used.

RESULTS

Among 15 patients in the first stage, no objective responses were observed. Two patients had stable disease. The median number of cycles on study per patient was 2 (1-6). The median progression free survival and overall survival were 55 days (95% confidence interval: 50-59) and 190 days (95% confidence interval: 93-227), respectively. No treatment related hospitalizations or deaths occurred. Treatment related grade 1-2 toxicities included nausea, vomiting (26.7% each), fatigue (20%), anorexia and diarrhea (13.3% each). Grade 3 anorexia, wheezing, agitation, abdominal pain and SGPT were observed in 1 patient each (6.7%). One patient experienced grade 4 hypoglycemia (6.7%).

CONCLUSIONS

Darinaparsin could be safely administered with tolerable toxicity profiles, and no QTc prolongation in patients with advanced HCC. However, at this dose and schedule, it has shown no objective responses in HCC and this trial was terminated as planned after the first stage of efficacy analysis.

Crocetin inhibits pancreatic cancer cell proliferation and tumor progression in a xenograft mouse model

Crocetin, a carotenoid compound derived from saffron, has long been used as a traditional ancient medicine against different human diseases including cancer. The aim of the series of experiments was to systematically determine whether crocetin significantly affects pancreatic cancer growth both in vitro and/or in vivo. For the in vitro studies, first, MIA-PaCa-2 cells were treated with crocetin and in these sets of experiments, a proliferation assay using H(3)-thymidine incorporation and flow cytometric analysis suggested that crocetin inhibited proliferation. Next, cell cycle proteins were investigated. Cdc-2, Cdc-25C, Cyclin-B1, and epidermal growth factor receptor were altered significantly by crocetin. To further confirm the findings of inhibition of proliferation, H(3)-thymidine incorporation in BxPC-3, Capan-1, and ASPC-1 pancreatic cancer cells was also significantly inhibited by crocetin treatment. For the in vivo studies, MIA-PaCa-2 as highly aggressive cells than other pancreatic cancer cells used in this study were injected into the right hind leg of the athymic nude mice and crocetin was given orally after the development of a palpable tumor. The in vivo results showed significant regression in tumor growth with inhibition of proliferation as determined by proliferating cell nuclear antigen and epidermal growth factor receptor expression in the crocetin-treated animals compared with the controls. Both the in vitro pancreatic cancer cells and in vivo athymic nude mice tumor, apoptosis was significantly stimulated as indicated by Bax/Bcl-2 ratio. This study indicates that crocetin has a significant antitumorigenic effect in both in vitro and in vivo on pancreatic cancer.

Stimulation of MCF-7 tumor progression in athymic nude mice by 17beta-estradiol induces WISP-2/CCN5 expression in xenografts: a novel signaling molecule in hormonal carcinogenesis

There was 100% solid tumor formation following inoculation of MCF-7 cells. However, MCF-7 tumor progression was significantly greater in the mice exposed to 17beta-estradiol (17beta-E2) compared to unexposed mice. WISP-2/CCN5 mRNA expression was correspondingly increased in 17beta-E2 exposed MCF-7 tumors compared to unexposed xenografts. Moreover, estrogen exposure followed by anti-estrogen tamoxifen treatment drastically inhibited the tumor growth and WISP-2 expression in nude mice. Therefore, the study suggests that higher WISP-2/CCN5 expression by estrogen may be associated with the estrogen-induced growth of MCF-7 tumors in vivo. Finally, overexpression of WISP-2/CCN5 may be considered as a prognostic marker of estrogen-sensitive tumor growth.