Bcl-2 and Bax expression predict prostate cancer outcome in men treated with androgen deprivation and radiotherapy on radiation therapy oncology group protocol 92-02

Modulation of Radiation Biomarkers in a Randomized Phase II Study of 131I-MIBG With or Without Radiation Sensitizers for Relapsed or Refractory Neuroblastoma

PURPOSE

¹³¹I-metaiodobenzylguanidine (¹³¹I-MIBG) has demonstrated efficacy as a single agent in neuroblastoma. Recent trials have focused on ¹³¹I-MIBG combination strategies, though little is known about the effect of putative radiosensitizers on biological markers of radiation exposure.

METHODS AND MATERIALS

NANT2011-01 evaluated ¹³¹I-MIBG therapy alone (arm A) or in combination with vincristine/irinotecan (arm B) or vorinostat (arm C) for patients with relapsed or refractory neuroblastoma. Blood samples were collected before and after ¹³¹I-MIBG infusion to determine levels of radiation-associated biomarkers (transcript and protein). The association of biomarker with treatment arm, clinical response, and treatment toxicity was analyzed.

RESULTS

The cohort included 99 patients who had at least 1 biomarker available for analysis. Significant modulation in most biomarkers between baseline, 72, and 96 hours following ¹³¹I-MIBG was observed. Patients in arm C had the lowest degree of modulation in FLT3 ligand protein. Lower baseline BCL2 transcript levels were associated with higher overall response. Patients with greater increases in FLT3 ligand at 96 hours after ¹³¹I-MIBG therapy were significantly more likely to have grade 4 thrombocytopenia. Peripheral blood gene expression of the BCL2 family of apoptotic markers (BCL2L1 and BAX transcripts) was significantly associated with grade 4 hematologic toxicity. RNA sequencing demonstrated little overlap in the top modulated peripheral blood transcripts between randomized arms.

CONCLUSIONS

Peripheral blood biomarkers relevant to radiation exposure demonstrate significant modulation after ¹³¹I-MIBG and concomitant radiation sensitizers affect extent of modulation. Biomarkers related to hematopoietic damage and apoptosis were associated with hematologic toxicity.

Multi-candidate immunohistochemical markers to assess radiation response and prognosis in prostate cancer: results from the CHHiP trial of radiotherapy fractionation

BACKGROUND

Protein markers of cellular proliferation, hypoxia, apoptosis, cell cycle checkpoints, growth factor signalling and inflammation in localised prostate tumours have previously shown prognostic ability. A translational substudy within the CHHiP trial of radiotherapy fractionation evaluated whether these could improve prediction of prognosis and assist treatment stratification following either conventional or hypofractionated radiotherapy.

METHODS

Using case:control methodology, patients with biochemical or clinical failure after radiotherapy (BCR) were matched to patients without recurrence according to established prognostic factors (Gleason score, presenting PSA, tumour-stage) and fractionation schedule. Immunohistochemical (IHC) staining of diagnostic biopsy sections was performed and scored for HIF1α, Bcl-2, Ki67, Geminin, p16, p53, p-chk1 and PTEN. Univariable and multivariable conditional logistic regression models, adjusted for matching strata and age, estimated the prognostic value of each IHC biomarker, including interaction terms to determine BCR prediction according to fractionation.

FINDINGS

IHC results were available for up to 336 tumours. PTEN, Geminin, mean Ki67 and max Ki67 were prognostic after adjusting for multiple comparisons and were fitted in a multivariable model (n = 212, 106 matched pairs). Here, PTEN and Geminin showed significant prediction of prognosis. No marker predicted BCR according to fractionation.

INTERPRETATION

Geminin or Ki67, and PTEN, predicted response to radiotherapy independently of established prognostic factors. These results provide essential independent external validation of previous findings and confirm a role for these markers in treatment stratification.

FUNDING

Cancer Research UK (BIDD) grant (A12518), Cancer Research UK (C8262/A7253), Department of Health, Prostate Cancer UK, Movember Foundation, NIHR Biomedical Research Centre at Royal Marsden/ICR.

Colon Targeted Eudragit Coated Beads Loaded with Optimized Fluvastatin-Scorpion Venom Conjugate as a Potential Approach for Colon Cancer Therapy: In Vitro Anticancer Activity and In Vivo Colon Imaging

Preclinical studies suggest that most of statins or 3‑hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors possess pleiotropic anticancer activity. The aim of the present work was to investigate the conjugation of the statin fluvastatin (FLV) with scorpion venom (SV), a natural peptide with proven anticancer properties, to enhance FLV cytotoxic activity and prepare colon targeted FLV-SV nanoconjugate beads for management of colon cancer. Response surface design was applied for the optimization of FLV-SV nanoconjugates. FLV-SV particle size and zeta potential were selected as responses. Cytotoxicity of optimized FLV-SV nanoconjugates was carried out on Caco2 cell line. Colon targeted alginate coated Eudragit S100 (ES100) beads for the optimized formula were prepared with the utilization of barium sulfate (BaSO4) as radiopaque contrast substance. Results revealed that optimized FLV-SV nanoconjugates showed a size of 71.21 nm, while the zeta potential was equal to 29.13 mV. Caco2 cells were considerably more sensitive to the FLV-SV formula (half-maximal inhibitory concentration (IC50) = 11.91 µg/mL) compared to SV and FLV used individually, as shown by values of IC50 equal to 30.23 µg/mL and 47.68 µg/mL, respectively. In vivo imaging of colon targeted beads, carried out by employing real-time X-ray radiography, confirmed the efficiency of colon targeted beads. Overall our results indicate that the optimized FLV-SV nanoconjugate loaded alginate coated ES100 beads could represent a promising approach for colon cancer with efficient colon targeting ability.

Targeting the Intrinsic Apoptosis Pathway: A Window of Opportunity for Prostate Cancer

Simple Summary

Prostate cancer treatment has improved over the last 20 years; despite this, approximately 33,000 men died from the disease in the United States in 2020. In view of this, new treatment options are urgently needed for advanced prostate cancer. Eradicating cancer cells by triggering apoptosis (a form of cell death) is an attractive strategy, and a novel class of drugs, called BH3 mimetics, have been designed to do this. They have been shown to work for blood cancers and may also have a role in solid cancers. Herein, we discuss cell death, focusing on the intrinsic apoptosis pathway, and consider how BH3 mimetics may be used to help treat prostate cancer.

Abstract

Despite major improvements in the management of advanced prostate cancer over the last 20 years, the disease remains invariably fatal, and new effective therapies are required. The development of novel hormonal agents and taxane chemotherapy has improved outcomes, although primary and acquired resistance remains problematic. Inducing cancer cell death via apoptosis has long been an attractive goal in the treatment of cancer. Apoptosis, a form of regulated cell death, is a highly controlled process, split into two main pathways (intrinsic and extrinsic), and is stimulated by a multitude of factors, including cellular and genotoxic stress. Numerous therapeutic strategies targeting the intrinsic apoptosis pathway are in clinical development, and BH3 mimetics have shown promising efficacy for hematological malignancies. Utilizing these agents for solid malignancies has proved more challenging, though efforts are ongoing. Molecular characterization and the development of predictive biomarkers is likely to be critical for patient selection, by identifying tumors with a vulnerability in the intrinsic apoptosis pathway. This review provides an up-to-date overview of cell death and apoptosis, specifically focusing on the intrinsic pathway. It summarizes the latest approaches for targeting the intrinsic apoptosis pathway with BH3 mimetics and discusses how these strategies may be leveraged to treat prostate cancer.

Differential gene expression of BCL-2, ZEB2-AS1 and BALR-2 in prostate cancer and benign prostatic hyperplasia

Prostate cancer (PCa) and benign prostate hyperplasia (BPH) are highly prevalent heterogeneous disorders among men. Whereas PCa and BPH underline common pathological features, apoptotic-related genes might be differentially expressed in these diseases. This study was aimed at testing BCL-2 as well as BALR-2 and ZEB2-AS1 apoptosis-related long non-coding RNA (lncRNA) in patients with PCa and BPH. The expression levels of the BCL-2 gene and ZEB2-AS1 lncRNA were upregulated in tumoural tissues in comparison to adjacent non-cancerous tissues (ANCTs) and BPH tissues. In contrast, the expression level of BALR-2 lncRNA was significantly higher in BPH compared with tumoural tissues. Furthermore, while no association was noticed between the relative expression of ZEB2-AS1 and the tumour grade, the relative expression of BCL-2 and BALR-2 is strongly associated with a higher grade of the tumour in PCa samples compared with the ANCTs. The receiver operating characteristic (ROC) curve analysis indicated the highest specificity and diagnostic value in distinguishing PCa and ANCTs as well as PCa and BPH, respectively. In conclusion, altered expression of BCL-2 and BALR-2 was observed to be associated with tumoural progression and could be used as potential candidates for distinguishing PCa tissues from ANCTs or BPH samples.

The Role of BCL-2 Proteins in the Development of Castration-resistant Prostate Cancer and Emerging Therapeutic Strategies

The development of androgen resistance in advanced prostate cancer remains a challenging clinical problem. Because androgen deprivation therapy constitutes the backbone of first-line treatments for metastatic prostate cancer, the phenotypic switch from an androgen-dependent to an androgen-independent growth state limits the treatment options for these patients. This critical change from an androgen-dependent to an androgen-independent growth state can be regulated by the B-cell lymphoma gene 2 (BCL-2) family of apoptotic proteins. While the roles of BCL-2 protein family members in the carcinogenesis of prostate cancer have been well-studied, emerging data also delineates their modulation of disease progression to castration-resistant prostate cancer (CRPC). Over the past 2 decades, investigators have sought to describe the mechanisms that underpin this development at the molecular level, yet no recent literature has consolidated these findings in a dedicated review. As new classes of BCL-2 family inhibitors are finding indications for other cancer types, it is time to evaluate how such agents might find stable footing for the treatment of CRPC. Several trials to date have investigated BCL-2 inhibitors as therapeutic agents for CRPC. These therapies include selective BCL-2 inhibitors, pan-BCL-2 inhibitors, and novel inhibitors of MCL-1 and BCL-XL. This review details the research regarding the role of BCL-2 family members in the pathogenesis of prostate cancer and contextualizes these findings within the contemporary landscape of prostate cancer treatment.

Prostate Cancer Biomarkers: From diagnosis to prognosis and precision-guided therapeutics

Prostate cancer (PCa) is one of the most commonly diagnosed malignancies and among the leading causes of cancer-related death worldwide. It is a highly heterogeneous disease, ranging from remarkably slow progression or inertia to highly aggressive and fatal disease. As therapeutic decision-making, clinical trial design and outcome highly depend on the appropriate stratification of patients to risk groups, it is imperative to differentiate between benign versus more aggressive states. The incorporation of clinically valuable prognostic and predictive biomarkers is also potentially amenable in this process, in the timely prevention of metastatic disease and in the decision for therapy selection. This review summarizes the progress that has so far been made in the identification of the genomic events that can be used for the classification, prediction and prognostication of PCa, and as major targets for clinical intervention. We include an extensive list of emerging biomarkers for which there is enough preclinical evidence to suggest that they may constitute crucial targets for achieving significant advances in the management of the disease. Finally, we highlight the main challenges that are associated with the identification of clinically significant PCa biomarkers and recommend possible ways to overcome such limitations.

Lemur Tyrosine Kinases and Prostate Cancer: A Literature Review

The members of the Lemur Tyrosine Kinases (LMTK1-3) subfamily constitute a group of three membrane-anchored kinases. They are known to influence a wide variety of key cellular events, often affecting cell proliferation and apoptosis. They have been discovered to be involved in cancer, in that they impact various signalling pathways that influence cell proliferation, migration, and invasiveness. Notably, in the context of genome-wide association studies, one member of the LMTK family has been identified as a candidate gene which could contribute to the development of prostate cancer. In this review, of published literature, we present evidence on the role of LMTKs in human prostate cancer and model systems, focusing on the complex network of interacting partners involved in signalling cascades that are frequently activated in prostate cancer malignancy. We speculate that the modulators of LMTK enzyme expression and activity would be of high clinical relevance for the design of innovative prostate cancer treatment.

High Bax/Bcl-2 ratio is associated with good prognosis and better survival in patients with B cell chronic lymphocytic leukemia

Determination of Bax/Bcl-2 ratio may be a good predictive tool to recognize chronic lymphocytic leukemia (CLL) patients' outcome and prognosis to decide the time and type of therapy. This prospective study was carried out on 100 patients with newly diagnosed CLL. Bax and Bcl-2 expression in peripheral blood were measured by flow-cytometry. The association of Bax/Bcl-2 ratio with CLL laboratory markers, Rai stage, overall survival (OS) and progression-free survival (PFS) at 18 months was investigated. The sensitivity and specificity of Bax/Bcl-2 in predicting survival was evaluated. The best cut-off value of Bax/Bcl-2 ratio to predict the survival, detected by receiver operating characteristic (ROC) curve, was 1.2 with 80 % sensitivity and 60.86 % specificity. A ratio of ≤1.20 was detected in 78 % of patients and was associated with worse prognosis. A lower Bax/Bcl-2 ratio was associated with higher modified Rai stage at time of diagnosis and a significantly shorter both OS (64.1 % versus 90.9 %, p < 0.026) and PFS (66.7 % versus 90.9 %, p < 0.031) at 18 months. In multivariate analysis, bax/bcl-2 ≤ 1.2 was an independent prognostic factor for overall survival, (p = 0.025). We concluded that lower Bax /Bcl-2 ratios were associated with worse prognosis as evidenced by lower OS and PFS in CLL patients. It was also associated with markers of high tumor burden and unfavorable prognostic markers. Recognition of patients with low Bax /Bcl-2 ratio would make them good candidates for the novel Bcl-2 inhibitory targeted chemotherapy to avoid resistance to the traditional therapy.

Signaling Pathways That Control Apoptosis in Prostate Cancer

Prostate cancer is the second most common malignancy and the fifth leading cancer-caused death in men worldwide. Therapies that target the androgen receptor axis induce apoptosis in normal prostates and provide temporary relief for advanced disease, yet prostate cancer that acquired androgen independence (so called castration-resistant prostate cancer, CRPC) invariably progresses to lethal disease. There is accumulating evidence that androgen receptor signaling do not regulate apoptosis and proliferation in prostate epithelial cells in a cell-autonomous fashion. Instead, androgen receptor activation in stroma compartments induces expression of unknown paracrine factors that maintain homeostasis of the prostate epithelium. This paradigm calls for new studies to identify paracrine factors and signaling pathways that control the survival of normal epithelial cells and to determine which apoptosis regulatory molecules are targeted by these pathways. This review summarizes the recent progress in understanding the mechanism of apoptosis induced by androgen ablation in prostate epithelial cells with emphasis on the roles of BCL-2 family proteins and "druggable" signaling pathways that control these proteins. A summary of the clinical trials of inhibitors of anti-apoptotic signaling pathways is also provided. Evidently, better knowledge of the apoptosis regulation in prostate epithelial cells is needed to understand mechanisms of androgen-independence and implement life-extending therapies for CRPC.

Association of Monoamine Oxidase A with Tumor Burden and Castration Resistance in Prostate Cancer

BACKGROUND

Metastatic burden and aggressive behavior determine severity stratification and guide treatment decisions in prostate cancer (PCa). Monoamine oxidase A (MAOA) may promote tumor burden and drug/castration resistance in PCa. A positive association will pave the way for MAOA inhibitors such as moclobemide for PCa therapy.

OBJECTIVE

To analyze MAOA in peripheral blood mononuclear cells qualitatively and p38, c-Jun N-terminal kinases, nuclear factor kappa B, and their phosphorylated forms, vascular endothelial growth factor (angiogenesis), transforming growth factor beta, interleukin 6, and tumor necrosis factor-α (cytokines), Bcl-2 associated X, B-cell lymphoma 2, and P53 (apoptosis), prostate-specific membrane antigen, and epithelial cell adhesion molecules (surface markers) in plasma of patients with PCa.

METHODS

This was a 1-year pilot study in which patients with PCa were recruited and stratified into 2 groups and subgroups: treatment-naive with (M1) (n = 23) or without (M0) (n = 23) bone metastasis; hormone-sensitive prostate cancer (n = 26) or hormone/castration-resistant prostate cancer (n = 26). MAOA was detected using ELISA and other proteins were detected using immunoblotting technique.

RESULTS

MAOA was detected in 8.6% of M0 compared with 30.4% of M1 patients, and in 7.7% of hormone-sensitive compared with 27% of hormone/castration resistant PCa patients, associating it with bone metastasis and castration resistance. Multivariable regression analysis showed a correlation of MAOA with serum prostate-specific antigen, a marker for progression in PCa (Pearson correlation coefficient r = 0.30; P < 0.01). In patients with positive MAOA, there was overexpression of p38, phosphorylated-p38, c-Jun N-terminal kinases, phosphorylated c-Jun N-terminal kinases, nuclear factor kappa B, phosphorylated nuclear factor kappa B, transforming growth factor beta, vascular endothelial growth factor, interleukin 6, tumor necrosis factor α, Bcl-2 associated X, B-cell lymphoma 2, prostate-specific membrane antigen, and epithelial cell adhesion molecule in M1 compared with M0 group patients, associating these proteins with tumor burden. Overexpression of Bcl-2 associated X, tumor protein 53, c-Jun N-terminal kinases, nuclear factor kappa B, transforming growth factor beta, vascular endothelial growth factor, and prostate-specific membrane antigen and underexpression of B-cell lymphoma 2 and phosphorylated nuclear factor kappa B were observed in hormone-sensitive prostate cancer compared with hormone/castration-resistant prostate cancer, associating these proteins with castration resistance.

CONCLUSIONS

Association of key molecules of oncogenesis and metastasis with MAOA suggests that MAOA inhibitors such as moclobemide might be effective in the management of PCa.

Interplay between orphan nuclear receptors and androgen receptor-dependent or-independent growth signalings in prostate cancer

It is well-established that both the initial and advanced growth of prostate cancer depends critically on androgens and thus on the activated androgen receptor (AR) -mediated signaling pathway. The unique hormone-dependent feature of prostate cancer forms the biological basis of hormone or androgen-deprivation therapy (ADT) that aims to suppress the AR signaling by androgen depletion or AR antagonists. ADT still remains the mainstay treatment option for locally advanced or metastatic prostate cancer. However, most patients upon ADT will inevitably develop therapy-resistance and progress to relapse in the form of castration-resistant disease (castration-resistant prostate cancer or CRPC) or even a more aggressive androgen-independent subtype (therapy-related neuroendocrine prostate cancer or NEPC). Recent advances show that besides AR, some ligand-independent members of nuclear receptor superfamily-designated as orphan nuclear receptors (ONRs), as their endogenous physiological ligands are either absent or not yet identified to date, also play significant roles in the growth regulation of prostate cancer via multiple AR-dependent or -independent (AR-bypass) pathways or mechanisms. In this review, we summarize the recent progress in the newly elucidated roles of ONRs in prostate cancer, with a focus on their interplay in the AR-dependent pathways (intratumoral androgen biosynthesis and suppression of AR signaling) and AR-independent pathways or cellular processes (hypoxia, oncogene- or tumor suppressor-induced senescence, apoptosis and regulation of prostate cancer stem cells). These ONRs with their newly characterized roles not only can serve as novel biomarkers but also as potential therapeutic targets for management of advanced prostate cancer.

Apoptotic and predictive factors by Bax, Caspases 3/9, Bcl-2, p53 and Ki-67 in prostate cancer after 12 Gy single-dose

Radio-induced apoptosis is mediated by the activation of tumor protein p53, Bax and caspases. The purpose of this study was to investigate the early activation of this pathway in men receiving in vivo irradiation immediately before radical prostatectomy for locally advanced prostate cancer. We also investigated cell proliferation index (Ki-67), proto-oncogene (p53) and anti-apoptotic protein (Bcl-2) levels as potential predictive factors. We selected a homogeneous sample of 20 patients with locally advanced prostate cancer and candidate to radical prostatectomy. To assess the apoptotic pathways, Bax, is studied through immunofluorescence assay, before and after 12 Gy single dose intraoperative radiotherapy (IORT) to the prostate, on bioptic samples and on surgical specimens. Moreover, before and after IORT, Bcl-2, p53, and Ki-67 were also detected through immunohistochemistry. A count of positive Bax spots for immunofluorescence was performed on tumor cells, prostatic intraepithelial neoplasia (PIN), and healthy tissue areas before and after IORT. We also analyzed Caspases 3 and 9 expressions after IORT. Before IORT, Bcl-2 mean value in neoplastic cells was 2.23% ± 1.95, mean Ki-67 in neoplastic area was 4.5% ± 3.8, and p53 was 22.5% ± 6.8. After IORT, Bcl-2 mean value in neoplastic cells was 8.85 ± 8.92%, Ki-67 in neoplastic area was 7.8 ± 6.09%, and p53 was 24.9 ± 26.4%. After the irradiation, healthy areas expressed significantly lower levels of Bax (2.81 ± 1.69%) with respect to neoplastic cells (p < 0.0001), while in PIN areas, Bax positive cells were significantly more present than in neoplastic areas (p = 0.0001). At statistical analysis, it was observed that cancer cells with Ki-67 ≥ 8% had a trend toward greater expression of Bax (p = 0.0641). We observed an increase of Bcl-2 expression after IORT in neoplastic areas (p = 0.0041). Biopsy specimens with p53 ≥ 18% and Ki-67 ≥ 8% had worse post-operative staging with extracapsular invasion (p = 0.04 for both parameters) and nodal positivity (p = 0.04 for p53 and p = 0.0001 at pathology for ki-67). No correlation between IORT and Caspases activation was noted. In conclusion, after 12 Gy IORT, Bax was overexpressed in tumor and PIN cells. Pre-operative Ki-67 and p53 definition could be used in future studies to predict patients with worse pathological stage, while Bcl-2 activation after IORT might be a predictive factor for loco-regional failure.

Prostate Cancer with Intraluminal Inclusions: the Association of the Immunophenotype with Grade Score

Background & Objective:

To study the immunophenotype of prostate cancer (PC) with the presence and absence of intraluminal inclusions (IIn), depending on the grade score.

Methods:

A total of 30 PC samples with IIn (group E) and 30 PC samples without them (group C) were studied. These groups were divided into 2 subgroups, depending on the grade of malignancy, which was determined according to the Gleason score as moderate and high-grade tumors. Macroscopic analysis, hematoxylin-eosin staining, immunohistochemistry (androgen receptors, p53 and Bax proteins, Hsp70 and Hsp90, CD68, VEGF, OSN, MMP-1) were used.

Results:

The expression level of VEGF was higher in the more differentiated tumors of the control group (P<0.01). Increased expression of prognostic-adverse markers p53 (in the presence of IIn, P<0.01) and MMP-1 (P<0.05) was observed. Also, a higher level of OSN expression was found in PC tissue with IIn (P<0.01) due to its participation in the processes of biomineralization. The expression level of CD68 and Bax protein was higher in the PC group with IIn (both P<0.01). Furthermore, Hsp90 had a significantly lower expression level in the PC of group E (P<0.05).

Conclusion:

the presence of IIn in the PC samples of group E promotes tissue remodeling with mechanical trauma, chronic inflammation, and fibrosis development. The presence of IIn in PC leads to the increase of OSN, CD68 and Bax expression and decrease of Hsp90 and VEGF expression. High expression of p53 and MMP-1 and low expression of OSN and VEGF was identified as a characteristic of high-grade tumors.

microRNA-205 and microRNA-338-3p Reduces Cell Apoptosis in Prostate Carcinoma Tissue and LNCaP Prostate Carcinoma Cells by Directly Targeting the B-Cell Lymphoma 2 (Bcl-2) Gene

Background

The inhibitor of apoptosis, B-cell lymphoma 2 (Bcl-2), is encoded by the BCL2 gene. Previous studies have shown that microRNAs are downregulated in prostate cancer. This study aimed to investigate the role of microRNA-205 and microRNA-338-3p and cell apoptosis in prostate carcinoma tissue and the LNCaP human prostate adenocarcinoma cell line by directly targeting the BCL2 gene and Bcl-2 protein expression.

Material/Methods

Bioinformatics methods predicted the target genes of miR-205 and miR-338-3p, which were validated by a luciferase assay. Immunohistochemistry was used to detect Bcl-2 protein expression in 30 samples of prostate carcinoma tissue and 30 matched samples of normal prostate. The normal prostate epithelial cell line, RWPE-1, and LNCaP human prostate adenocarcinoma cells studied in vitro. BCL2 mRNA expression and Bcl-2 protein expression were determined by quantitative polymerase chain reaction (q-PCR) and Western blot, respectively. Cell apoptosis was measured by flow cytometry using annexin V, fluorescein isothiocyanate, and phycoerythrin (annexin V-FITC/PE).

Results

TargetScan Human 7.2 predicted that the structures of miR-205 and miR-338-3p had a binding site on the proto-oncogene, BCL2, which was verified by a luciferase assay. The expression of miR-205 and miR-338-3p were significantly downregulated in prostate carcinoma tissues and LNCaP cells when compared with normal controls. BCL2 expression was significantly inhibited by overexpression of miR-205 and miR-338-3p in LNCaP cells.

Conclusions

The results of this study showed that miR-205 and miR-338-3p downregulated the expression of the BCL2 gene and decreased apoptosis in prostate carcinoma.

BCL2-overexpressing prostate cancer cells rely on PARP1-dependent end-joining and are sensitive to combined PARP inhibitor and radiation therapy

Here we report that BCL2 blocks DNA double strand break (DSB) repair via nonhomologous end-joining (NHEJ), through sequestration of KU80 protein outside the nucleus. We find that this effect is associated with a repair switch to the error-prone PARP1-dependent end-joining (PARP1-EJ). We present in-vitro proof-of-concept for therapeutic targeting of this switch using PARP inhibitor to specifically enhance the radiosensitivity of BCL2-overexpressing cells. Given its erroneous behavior, PARP1-EJ might allow for the accumulation of genetic alterations and tumor progression. Consistently, we report an inverse correlation between BCL2 expression and biochemical recurrence-free survival of 10.259 prostate cancer (PCa) patients who underwent primary radical-prostatectomy for localized disease. Further, we evaluated retrospectively the impact of BCL2 expression on clinical outcome of 1.426 PCa patients, who had been given salvage radiotherapy at relapse after radical prostatectomy. In line with its role in blocking NHEJ, BCL2 over-expressers showed significantly better response to salvage radiotherapy compared to low-expressers. Collectively, our findings identify BCL2 status in PCa as a putative predictor of (i) radiotherapy response and (ii) response to treatment with PARP inhibitor olaparib as a radiosensitizing agent.

Bax, Bcl-2, and Bax/Bcl-2 as prognostic markers in acute myeloid leukemia: are we ready for Bcl-2-directed therapy?

Purpose

Many anticancer drugs induce apoptosis in malignant cells, and resistance to apoptosis could lead to suboptimal or no therapeutic benefit. Two cytoplasmic proteins, B-cell lymphoma protein 2 (Bcl-2)-associated X (Bax) and Bcl-2, act as a promoter and an inhibitor of apoptosis, respectively. Both Bax and Bcl-2 as well as their ratio have been regarded as prognostic markers in various cancers. However, conflicting results have been reported. A clear understanding of apoptosis has also become crucial due to reports about anti-Bcl-2 chemotherapy. We explored the relationship of Bax and Bcl-2 gene expression and their ratio with the therapeutic response in acute myeloid leukemia (AML) patients.

Patients and methods

Bone marrow and/or blood samples from 90 AML patients treated with cytarabine and daunorubicin were included. Expression of Bax and Bcl-2 was determined through real-time polymerase chain reaction by using ΔΔCt method of relative expression.

Results

Bax and Bcl-2 expression among marrow and blood samples correlated with each other (r_s=0.5, p<0.01). Although bone marrow expression of Bax and Bcl-2 tended to remain higher among responders (median 1.01 and 0.29, respectively) as compared to non-responders (median 0.66 and 0.24, respectively), the difference failed to reach statistical significance (U=784.5 and 733; p=0.68 and 0.28, respectively). Conversely, Bax/Bcl-2 ratio was higher among poor responders (median 3.07 vs 1.78), though again failed to reach statistical significance (U=698.5, p=0.07).

Conclusion

Expression of Bax and Bcl-2 does not differ significantly among AML patients treated with cytarabine and daunorubicin in terms of remission, relapse, resistance, overall survival, and disease-free survival, thus questioning the utility of emerging anti-Bcl-2 therapy.

Systemic Delivery of Bc12-Targeting siRNA by DNA Nanoparticles Suppresses Cancer Cell Growth

Short interfering RNA (siRNA) is a promising molecular tool for cancer therapy, but its clinical success is limited by the lack of robust in vivo delivery systems. Rationally designed DNA nanoparticles (DNPs) have emerged as facile delivery vehicles because their physicochemical properties can be precisely controlled. Nonetheless, few studies have used DNPs to deliver siRNAs in vivo, and none has demonstrated therapeutic efficacy. Herein, we constructed a number of DNPs of rectangular and tubular shapes with varied dimensions using the modular DNA brick method for the systemic delivery of siRNA that targets anti-apoptotic protein Bcl2. The siRNA delivered by the DNPs inhibited cell growth both in vitro and in vivo, which suppressed tumor growth in a xenograft model that specifically correlated with Bcl2 depletion. This study suggests that DNPs are effective tools for the systemic delivery of therapeutic siRNA and have great potential for further clinical translation.

Screening candidate microRNA-mRNA regulatory pairs for predicting the response to chemoradiotherapy in rectal cancer by a bioinformatics approach

Extensive efforts have been undertaken in search of biomarkers for predicting the chemoradiotherapy response in rectal cancer. However, most attention on treatment efficiency prediction in carcinoma is addicted to single or limited molecules. Network biomarkers are considered to outperform single molecules in predictive power. In this study, candidate microRNAs (miRNAs) were identified from the PubMed citations and miRNA expression profiles. Targets of miRNAs were obtained from four experimentally confirmed interactions and three computationally predicted databases. Functional enrichment analysis of all the targets revealed their associations with chemoradiotherapy response, indicating they could be promising biomarkers. Two lists of key target mRNAs of the candidate miRNAs were retrieved from protein–protein interaction (PPI) network and mRNA expression profiles, respectively. Pathway analysis and literature validation revealed that the mRNA lists were highly related to the ionizing radiation. The above miRNAs along with the key miRNA targets provide potential miRNA-mRNA regulatory pairs as network biomarkers in which all the network components may be used for predicting the chemoradiotherapy response. These results demonstrated that the network biomarkers could provide a useful model for predicting the chemoradiotherapy response and help in further understanding the molecular basis of response differences, which should be prioritized for further study.

BCL2 genotypes and prostate cancer survival

Purpose

The antiapoptotic B‑cell lymphoma 2 (BCL2) gene is a key player in cancer development and progression. A functional single-nucleotide polymorphism (c.-938C>A, rs2279115) in the inhibitory P2 BCL2 gene promoter has been associated with clinical outcomes in various types of cancer. Aim of the present study was to analyze the role of BCL2-938C>A genotypes in prostate cancer mortality.

Methods

The association between BCL2-938C>A (rs2279115) genotypes and prostate cancer outcome was studied within the prospective PROCAGENE study comprising 702 prostate cancer patients.

Results

During a median follow-up time of 92 months, 120 (17.1%) patients died. A univariate Cox regression model showed a significant association of the CC genotype with reduced cancer-specific survival (CSS; hazard ratio, HR, 2.13, 95% confidence interval, CI, 1.10–4.12; p = 0.024) and overall survival (OS; HR 2.34, 95% CI 1.58–3.47; p < 0.001). In a multivariate Cox regression model including age at diagnosis, risk group, and androgen deprivation therapy, the CC genotype remained a significant predictor of poor CSS (HR 2.05, 95% CI 1.05–3.99; p = 0.034) and OS (HR 2.25, 95% CI 1.51–3.36; p < 0.001).

Conclusion

This study provides evidence that the homozygous BCL2-938 CC genotype is associated with OS and C in prostate cancer patients.

Prospective Validation of Diagnostic Tumor Biomarkers in Men Treated With Radiotherapy for Prostate Cancer

Background

In prior retrospective studies, we assessed a number of prostate tumor tissue biomarkers that were associated independently with the clinical outcome of men treated with radiotherapy (RT) ± androgen deprivation therapy (ADT). In this report, the associations of selected biomarkers with biochemical or clinical disease failure (BCDF) were prospectively evaluated in men with T1-T3 prostate cancer on a randomized hypofractionation trial.

Methods

Biomarkers were analyzed in 263 of 303 men randomly assigned to standard vs moderate hypofractionation. Median follow-up was 65.9 months. Archival tissue was analyzed for Ki-67 (n = 231), MDM2 (n = 209), p16 (n = 195), Cox-2 (n = 126), p53 (n = 206), bcl2 (n = 223), bax (n = 210), and PKA (n = 160). The base model for multivariable Fine-Gray regression analysis included treatment assignment and risk groups. All statistical tests were two-sided.

Results

Each biomarker was tested one at a time relative to the base model and selected for inclusion in multivariable analysis. Ki-67 (hazard ratio [HR] = 2.31, 95% confidence interval [CI] = 1.19 to 4.48, P = .01) and bcl2&bax (HR = 2.19, 95% CI = 1.08 to 4.46, P = .03) were statistically significantly related to higher BCDF and were independently statistically significant when considered jointly (Ki-67: HR = 2.26, 95% CI = 1.12 to 4.58, P = .02; bcl2&bax: HR = 2.14, 95% CI = 1.03 to 4.41, P = .04). At 2.5 years postradiotherapy, the C-index of Ki-67 was 73.2%, while for the base model was only 46.2%; Ki-67 was the most statistically significant when tested without bcl2&bax.

Conclusions

In this prospective multiple biomarker analysis in men with prostate cancer treated with RT±ADT, both Ki-67 and bcl2&bax were independently related to early BCDF; however, Ki-67 alone is indicated to be the most clinically meaningful by C-index analysis and is universally available.

Effect of a chemical inhibitor of human phosphatidylethanolamine-binding protein 4 on radiosensitivity of rectal cancer cells

BACKGROUND

Human phosphatidylethanolamine-binding protein 4 (hPEBP4) is a well-established antiapoptosis molecule in recent years. It has also been demonstrated to be involved in the radioresistance of rectal cancer. The objective of this study was to determine whether IOI-42, a chemical inhibitor of hPEBP4, could sensitize rectal cancer cells.

METHODS

Rectal cancer cells were treated with IOI-42 alone or in combination with irradiation. Clonogenic survival assays and tumor volume growth analysis were used, respectively, to study the effect of IOI-42 in vitro and in vivo. Western blot was adopted to measure the activation of signal pathway.

RESULTS

Clonogenic survival assays showed that IOI-42, combined with irradiation, caused a significant decrease in colony formation compared with radiation alone, which was associated with the downregulation of Akt activation. And we also confirmed the effect of IOI-42 in nude mice transplanted with human rectal cancer subcutaneously.

CONCLUSIONS

These data suggest that IOI-42 has a potential to enhance the radiosensitivity of rectal cancer cells, providing a rationale to further investigate the feasibility of combining of IOI-42 with radiation, keeping in mind that this may result in unexpected toxicities.

Apoptotic Pathways Linked to Endocrine System as Potential Therapeutic Targets for Benign Prostatic Hyperplasia

Benign prostatic hyperplasia (BPH) is a chronic condition common in older men that can result in bothersome lower urinary tract symptoms. The molecular mechanisms and networks underlying the development and the progression of the disease are still far from being fully understood. BPH results from smooth muscle cell and epithelial cell proliferation, primarily within the transition zone of the prostate. Apoptosis and inflammation play important roles in the control of cell growth and in the maintenance of tissue homeostasis. Disturbances in molecular mechanisms of apoptosis machinery have been linked to BPH. Increased levels of the glycoprotein Dickkopf-related protein 3 in BPH cause an inhibition of the apoptosis machinery through a reduction in B cell lymphoma (Bcl)-2 associated X protein (Bax) expression. Inhibitors of apoptosis proteins influence cell death by direct inhibition of caspases and modulation of the transcription factor nuclear factor-κB. Current pharmacotherapy targets either the static component of BPH, including finasteride and dutasteride, or the dynamic component of BPH, including α-adrenoceptor antagonists such as tamsulosin and alfuzosin. Both these classes of drugs significantly interfere with the apoptosis machinery. Furthermore, phytotherapic supplements and new drugs may also modulate several molecular steps of apoptosis.

Mechanistic Insights into Molecular Targeting and Combined Modality Therapy for Aggressive, Localized Prostate Cancer

Radiation therapy (RT) is one of the mainstay treatments for prostate cancer (PCa). The potentially curative approaches can provide satisfactory results for many patients with non-metastatic PCa; however, a considerable number of individuals may present disease recurrence and die from the disease. Exploiting the rich molecular biology of PCa will provide insights into how the most resistant tumor cells can be eradicated to improve treatment outcomes. Important for this biology-driven individualized treatment is a robust selection procedure. The development of predictive biomarkers for RT efficacy is therefore of utmost importance for a clinically exploitable strategy to achieve tumor-specific radiosensitization. This review highlights the current status and possible opportunities in the modulation of four key processes to enhance radiation response in PCa by targeting the: (1) androgen signaling pathway; (2) hypoxic tumor cells and regions; (3) DNA damage response (DDR) pathway; and (4) abnormal extra-/intracell signaling pathways. In addition, we discuss how and which patients should be selected for biomarker-based clinical trials exploiting and validating these targeted treatment strategies with precision RT to improve cure rates in non-indolent, localized PCa.

The acute lymphoblastic leukemia prognostic scoring whether it is possible by BCL-2, BAX gene promoter genotyping

BACKGROUND

BCL-2 is the most important anti-apoptotic regulator and Bax is a pro-apoptotic protein. The status of these parameters or the ration of BCL-2 to BAX is important in malignant cell fate as well as normal cells.

METHODS

Sixty-two ALL patients and 62 healthy sex-and age-matched controls were studied. After genotyping, the promoter region of the BAX and BCL-2 genes by RFLP-PCR method the patients were classified in nine prognostic groups, after that, the overall survival ratio of each score was compared with others pair-wise or between groups.

RESULTS

The frequencies of the AA, AC, CC alleles of the BCL-2 C-938A polymorphism in patient group were 33 (53.23%), 18 (29.03%), 11 (17.74%), and in the control group were 13 (21.0%), 27 (43.5%), 22 (35.5%), respectively (P=0.003). Also, the frequencies of AA, AG, GG alleles of the BAX G-248A SNP were 15 (24.2%), 24 (38.7%), 23 (37.1%) in ALL group and 13 (21.0%), 25 (40.3%), 24 (38.7%) (p>0.05) in the control group. The survival time estimation and ratio were significantly different between different SNPs in BCL-2 (P=0.002).

CONCLUSION

These findings showed that the BCL-2 promoter region polymorphism is more reliable than BAX gene promoter polymorphism in any ALL scoring system. But the establishment of complete scoring system requires further more clinical and laboratory findings along with genetic polymorphisms is necessary.

Genomic and Histopathological Tissue Biomarkers That Predict Radiotherapy Response in Localised Prostate Cancer

Localised prostate cancer, in particular, intermediate risk disease, has varied survival outcomes that cannot be predicted accurately using current clinical risk factors. External beam radiotherapy (EBRT) is one of the standard curative treatment options for localised disease and its efficacy is related to wide ranging aspects of tumour biology. Histopathological techniques including immunohistochemistry and a variety of genomic assays have been used to identify biomarkers of tumour proliferation, cell cycle checkpoints, hypoxia, DNA repair, apoptosis, and androgen synthesis, which predict response to radiotherapy. Global measures of genomic instability also show exciting capacity to predict survival outcomes following EBRT. There is also an urgent clinical need for biomarkers to predict the radiotherapy fraction sensitivity of different prostate tumours and preclinical studies point to possible candidates. Finally, the increased resolution of next generation sequencing (NGS) is likely to enable yet more precise molecular predictions of radiotherapy response and fraction sensitivity.

Heat shock and other apoptosis-related proteins as therapeutic targets in prostate cancer

Defects within apoptotic pathways have been implicated in prostate cancer (PCa) tumorigenesis, metastatic progression and treatment resistance. A hallmark of cancers is the ability to derail apoptosis by inhibiting the apoptotic signal, reducing the expression of apoptotic proteins and/or amplifying survival signals through increased production of antiapoptotic molecule. This review describes associations between heat shock proteins (HSPs) and the human androgen receptor (AR), the role of HSPs and other stress-induced proteins in PCa development and emerging strategies in targeting these protective proteins to treat PCa.

A tissue biomarker-based model that identifies patients with a high risk of distant metastasis and differential survival by length of androgen deprivation therapy in RTOG protocol 92-02

PURPOSE

To examine the relationship between the expression of 7 promising apoptotic/cell proliferation proteins (Ki-67, p53, MDM2, bcl-2, bax, p16, and Cox-2) and risk of distant metastasis.

EXPERIMENTAL DESIGN

RTOG 92-02 compared external beam radiotherapy (EBRT) to approximately 70 Gy + short-term androgen deprivation therapy (STADT) with EBRT + long-term ADT (LTADT). Immunohistochemical analysis was available for ≥4 biomarkers in 616 of 1,521 assessable cases. Biomarkers were evaluated individually and jointly via multivariable modeling of distant metastasis using competing risks hazards regression, adjusting for age, prostate-specific antigen, Gleason score, T stage, and treatment.

RESULTS

Modeling identified four biomarkers (Ki-67, MDM2, p16 and Cox-2) that were jointly associated with distant metastasis. The c-index was 0.77 for the full model and 0.70 for the model without the biomarkers; a relative improvement of about 10% (likelihood ratio P < 0.001). Subdivision of the patients into quartiles based on predicted distant metastasis risk identified a high-risk group with 10-year distant metastasis risk of 52.5% after EBRT + STADT and 31% with EBRT + LTADT; associated 10-year prostate cancer-specific mortality (PCSM) risks were 45.9% and 14.5% with STADT and LTADT.

CONCLUSION

Four biomarkers were found to contribute significantly to a model that predicted distant metastasis and identified a subgroup of patients at a particularly high risk of both distant metastasis and PCSM when EBRT + STADT was used. LTADT resulted in significant reductions in distant metastasis and improvements in PCSM, and there was a suggestion of greater importance in the very high risk subgroup.

Prognostic significance of B-cell lymphoma 2 expression in acute leukemia: A systematic review and meta-analysis

A number of studies have provided estimates of the correlation between B-cell lymphoma 2 (Bcl-2) expression and its clinical significance in acute leukemia (AL); however, the results have been heterogeneous. In order to clarify the prognostic significance of Bcl-2 status in patients with AL, a systematic review and meta-analysis of 5 published studies including a total of 665 subjects was performed. The reported frequency of Bcl-2 expression was 0-99.00%. Bcl-2-positive patients had a higher median white blood cell count compared to Bcl-2-negative patients. Additionally, Bcl-2-negative patients had >2-fold higher odds of achieving complete remission (CR) compared to Bcl-2-positive patients. The summary hazard ratio of Bcl-2 negativity/positivity for CR was 0.62 [95% confidence interval: 0.53-0.81, P<0.001]. Although this meta-analysis was based on data abstracted from observational studies, our results may justify the use of risk-adapted therapeutic strategies for AL according to the Bcl-2 expression status.

Molecular markers for prostate cancer in formalin-fixed paraffin-embedded tissues

Prostate cancer (PCa) is the most frequently diagnosed type of cancer in developed countries. The decisive method of diagnosis is based on the results of biopsies, morphologically evaluated to determine the presence or absence of cancer. Although this approach leads to a confident diagnosis in most cases, it can be improved by using the molecular markers present in the tissue. Both miRNAs and proteins are considered excellent candidates for biomarkers in formalin-fixed paraffin-embedded (FFPE) tissues, due to their stability over long periods of time. In the last few years, a concerted effort has been made to develop the necessary tools for their reliable measurement in these types of samples. Furthermore, the use of these kinds of markers may also help in establishing tumor grade and aggressiveness, as well as predicting the possible outcomes in each particular case for the different treatments available. This would aid clinicians in the decision-making process. In this review, we attempt to summarize and discuss the potential use of microRNA and protein profiles in FFPE tissue samples as markers to better predict PCa diagnosis, progression, and response to therapy.

ABT-737, a small molecule Bcl-2/Bcl-xL antagonist, increases antimitotic-mediated apoptosis in human prostate cancer cells

Castration-resistant prostate cancer (CRPC) expresses high levels of the anti-apoptotic proteins Bcl-2, Bcl-xL and Mcl-1, resulting in resistance to apoptosis and association with poor prognosis. Docetaxel, an antimitotic drug that is the first-line treatment strategy for CRPC, is known to provide a small survival benefit. However, docetaxel chemotherapy alone is not enough to counteract the high levels of Bcl-2/Bcl-xL/Mcl-1 present in CRPC. ABT-737 is a small molecule that binds to Bcl-2/Bcl-xL (but not Mcl-1) with high affinity and disrupts their interaction with pro-apoptotic Bax/Bak, thus enhancing apoptosis. Our results indicate that ABT-737 can sensitize androgen-dependent LNCaP and CRPC PC3 cells to docetaxel- and to the novel antimitotic ENMD-1198-mediated caspase-dependent apoptosis. CRPC DU145 cells, however, are more resistant to ABT-737 because they are Bax null and not because they express the highest levels of anti-apoptotic Mcl-1 (associated with ABT-737 resistance). Knockdown of Bax or Bak in LNCaP indicates that ABT-737-induced antimitotic enhancement of apoptosis is more dependent on the levels of Bax than Bak. Furthermore, we find that the ability of docetaxel to increase cyclin B1/Cdk1-mediated phosphorylation of Bcl-2/Bcl-xL and decrease Mcl-1 is required for ABT-737 to enhance apoptosis in PC3 cells, as determined by addition of Cdk1 inhibitor purvalanol A and expression of shRNA specific for cyclin B1. Overall, our data suggests that the high levels of anti-apoptotic proteins in Bax-expressing CRPC cells can be overcome by targeting Bcl-2/Bcl-xL with ABT-737 and Mcl-1 with antimitotics.

Targeting the apoptosis pathway in prostate cancer

Important inroads have been made in the understanding and treatment of metastatic prostate cancer in recent years. However, the need for agents targeting novel pathways remains ever present. One such area with promise is through apoptosis or programmed cell death. Many perturbations within the apoptotic process have been associated with treatment resistance and progression in castration-resistant prostate cancer; thus, therapeutic potential exists with agents that can restore an effective apoptotic response to cellular stressors. This article focuses on agents in clinical development targeting apoptosis through the intrinsic and extrinsic pathways. We review the current status of agents that intervene at the Bcl2 checkpoints, humanized antibodies to death receptors, agents that target the inhibitors of apoptosis proteins, mimetics of small mitochondria-derived activator of caspases, and antisense therapies targeting cytoprotective chaperones. Although single-agent activity has been demonstrated with some of these agents, the clinical development path forward will see them coupled with standard hormonal therapy and chemotherapy. OGX-011 (custirsen), which inhibits expression of the cytoprotective chaperone protein clusterin, is the most mature of these agents and is being tested in combination with chemotherapy in phase III clinical trials for castration-resistant prostate cancer, and results are eagerly awaited.

RRM2 regulates Bcl-2 in head and neck and lung cancers: a potential target for cancer therapy

PURPOSE

Ribonucleotide reductase subunit M2 (RRM2) plays an active role in tumor progression. Recently, we reported that depletion of RRM2 by systemic delivery of a nanoparticle carrying RRM2-specific siRNA suppresses head and neck tumor growth. The aim of this study is to clarify the underlying mechanism by which RRM2 depletion inhibits tumor growth.

EXPERIMENTAL DESIGN

siRNA-mediated gene silencing was carried out to downregulate RRM2. Immunoblotting, reverse-transcriptase PCR, confocal microscopy, tissue fractionation, gene overexpression and knockdown were employed to analyze critical apoptosis signaling. Conventional immunohistochemistry and quantum dot-based immunofluorescence were applied to detect RRM2 and Bcl2 expression and localization in tissue samples from patients and mice.

RESULTS

Knockdown of RRM2 led to apoptosis through the intrinsic pathway in head and neck squamous cell carcinoma (HNSCC) and non-small cell lung cancer (NSCLC) cell lines. We showed that Bcl-2 is a key determinant controlling apoptosis, both in vitro and in vivo, and that RRM2 depletion significantly reduces Bcl-2 protein expression. We observed that RRM2 regulates Bcl-2 protein stability, with RRM2 suppression leading to increased Bcl-2 degradation, and identified their colocalization in HNSCC and NSCLC cells. In a total of 50 specimens each from patients with HNSCC and NSCLC, we identified the colocalization of Bcl-2 and RRM2 and found a significant positive correlation between their expression in HNSCC (R = 0.98; P < 0.0001) and NSCLC (R = 0.92; P < 0.0001) tumor tissues.

CONCLUSIONS

Our novel findings add to the knowledge of RRM2 in regulating expression of the antiapoptotic protein Bcl-2 and reveal a critical link between RRM2 and Bcl-2 in apoptosis signaling.

The role of intracrine androgen metabolism, androgen receptor and apoptosis in the survival and recurrence of prostate cancer during androgen deprivation therapy

Prostate cancer (CaP) is the most frequently diagnosed cancer and leading cause of cancer death in American men. Almost all men present with advanced CaP and some men who fail potentially curative therapy are treated with androgen deprivation therapy (ADT). ADT is not curative and CaP recurs as the lethal phenotype. The goal of this review is to apply our current understanding of CaP and castration-recurrent CaP (CR-CaP) to earlier studies that characterized ADT and the molecular mechanisms that facilitate the transition from androgen-stimulated CaP to CR-CaP. Reexamination of earlier studies also may provide a better understanding of how more newly recognized mechanisms, such as intracrine metabolism, may be involved with the early events that allow CaP survival after initiation of ADT and subsequent development of CR-CaP.

Ki-67 is an independent predictor of metastasis and cause-specific mortality for prostate cancer patients treated on Radiation Therapy Oncology Group (RTOG) 94-08

PURPOSE

The association of Ki-67 staining index (Ki67-SI) with overall survival (OS), disease-specific mortality (DSM), distant metastasis (DM), and biochemical failure (BF) was examined in men with favorable- to intermediate-risk prostate cancer receiving radiation therapy (RT) alone or with short-term androgen deprivation (ADT) in Radiation Therapy Oncology Group (RTOG) 94-08.

METHODS AND MATERIALS

468 patients (23.6%) on RTOG 94-08 had sufficient tissue for Ki67-SI analysis. The median follow-up time was 7.9 years. Ki67-SI was determined by immunohistochemistry and quantified manually and by image analysis. Correlative analysis versus clinical outcome was performed using the third quartile (≥Q3) cutpoint. A proportional hazards multivariable analysis (MVA) dichotomized covariates in accordance with trial stratification and randomization criteria.

RESULTS

In MVAs adjusted for all treatment covariates, high Ki67-SI (≥Q3) was correlated with increased DSM (hazard ratio [HR] 2.48, P=.03), DM (HR 3.5, P=.002), and BF (HR 3.55, P<.0001). MVA revealed similar Ki67-associated hazard ratios in each separate treatment arm for DSM, DM, and BF; these reached significance only for DM in the RT-alone arm and for BF in both arms. Ki67-SI was not a significant predictor of intraprostatic recurrence assessed by repeated biopsy 2 years after treatment. Patients with a high or low Ki67-SI seemed to experience a similar relative benefit from the addition of ADT to radiation.

CONCLUSIONS

High Ki67-SI independently predicts for increased DSM, DM, and protocol BF in primarily intermediate-risk prostate cancer patients treated with RT with or without ADT on RTOG 94-08 but does not predict for local recurrence or for increased relative benefit from ADT. This and prior studies lend support for the use of Ki67-SI as a stratification factor in future trials.

Systematic review of hypofractionated radiation therapy for prostate cancer

Prostate cancer is the second most prevalent solid tumor diagnosed in men in the United States and Western Europe. Conventionally fractionated external beam radiation therapy (1.8-2.0 Gy/fraction) is an established treatment modality for men in all disease risk groups. Emerging evidence from experimental and clinical studies suggests that the α/β ratio for prostate cancer may be as low as 1.5 Gy, which has prompted investigators around the world to explore moderately hypofractionated radiation therapy (2.1-3.5 Gy/fraction). We review the impetus behind moderate hypofractionation and the current clinical evidence supporting moderate hypofractionated radiation therapy for prostate cancer. Although hypofractionated radiation therapy has many theoretical advantages, there is no clear evidence from prospective, randomized, controlled trials showing that hypofractionated schedules have improved outcomes or lower toxicity than conventionally fractionated regimens. Currently, hypofractionated schedules should only be used in the context of clinical trials. High dose rate brachytherapy and stereotactic body radiation therapy (fraction size 3.5 Gy and greater) are alternative approaches to hypofractionation, but are beyond the scope of this report.

The role of treatment modality on the utility of predictive tissue biomarkers in clinical prostate cancer: a systematic review

BACKGROUND

Tissue biomarkers could pivotally improve clinical outcome prediction following prostate cancer therapy. Clinically, prostate cancer is managed by diverse treatment modalities whose individual influence on a biomarker's predictive ability is not well understood and poorly investigated in the literature.

OBJECTIVE

We conducted a systematic review to assess the predictive value of biomarkers in different treatment contexts in prostate cancer.

STUDY METHODOLOGY

A literature search was performed using the MeSH headings "prostate neoplasms" and "biological markers". Rigorous selection criteria identified studies correlating expression with clinical outcomes from primary androgen deprivation therapy (ADT), radical prostatectomy and radiotherapy (± neoadjuvant ADT).

STUDY RESULTS

Of 10,668 studies identified, 481 papers matched initial inclusion criteria. Following rescreening, 384 studies identified 236 individual tissue biomarkers, of which 29 were predictive on multivariate analysis in at least 2 independent cohorts. The majority were only tested in surgical cohorts. Only 8 predictive biomarkers were tested across all 3 treatments with Ki67 identified as universal predictive marker. p16 showed potential for treatment stratification between surgery and radiotherapy but needs further validation in independent studies.

CONCLUSIONS

Despite years of research, very few tissue biomarkers retain predictive value in independent validation across therapy context. Currently, none have conclusive ability to help treatment selection. Future biomarker research should consider the therapy context and use uniform methodology and evaluation criteria.

Tissue biomarkers for prostate cancer radiation therapy

Prostate cancer is the most common cancer and second leading cause of cancer deaths among men in the United States. Most men have localized disease diagnosed following an elevated serum prostate specific antigen test for cancer screening purposes. Standard treatment options consist of surgery or definitive radiation therapy directed by clinical factors that are organized into risk stratification groups. Current clinical risk stratification systems are still insufficient to differentiate lethal from indolent disease. Similarly, a subset of men in poor risk groups need to be identified for more aggressive treatment and enrollment into clinical trials. Furthermore, these clinical tools are very limited in revealing information about the biologic pathways driving these different disease phenotypes and do not offer insights for novel treatments which are needed in men with poor-risk disease. We believe molecular biomarkers may serve to bridge these inadequacies of traditional clinical factors opening the door for personalized treatment approaches that would allow tailoring of treatment options to maximize therapeutic outcome. We review the current state of prognostic and predictive tissue-based molecular biomarkers which can be used to direct localized prostate cancer treatment decisions, specifically those implicated with definitive and salvage radiation therapy.

[Prostate cancer: promising biomarkers related to aggressive disease]

BACKGROUND

Although a rapidly growing number of candidate biological markers of prognosis and/or response to specific treatments in prostate cancer, none have to date showed ability to completely prognosticate prostate cancer on evidence based urology.

OBJECTIVE

To review the pertinent literature on the issue.

ACQUISITION OF EVIDENCE

A comprehensive review of the current literature was done focusing on promising biomarkers related to aggressive prostate cancer.

SUMMARY OF EVIDENCE

Combined with the heterogeneous nature of the disease, mixed case series are the most common study design, impeding robust results and the development of an effective therapeutic strategy. Improvement in prostate cancer patient survival requires not only the identification of new therapeutic target based on detailed understanding of the biological mechanisms involved in metastatic dissemination and tumor growth but strong clinical studies as well.

CONCLUSION

Better study design involving potential markers and including well-classified and staged patients with robust methodology and adequate outcomes (mainly survival) are necessary to the field evolution.

Current challenges in development of differentially expressed and prognostic prostate cancer biomarkers

Introduction. Predicting the aggressiveness of prostate cancer at biopsy is invaluable in making treatment decisions. In this paper we review the differential expression of genes and microRNAs identified through microarray analysis as potentially useful markers for prostate cancer prognosis and discuss some of the challenges associated with their development. Methods. A review of the literature was conducted through Medline. Articles were identified through searches of the following terms: "prostate cancer AND differential expression", "prostate cancer prognosis", and "prostate cancer AND microRNAs". Results. Though numerous differentially expressed genes and microRNAs were identified as possible prognostic markers, the significance of several of these genes is either debated due to conflicting results or is not validated in other study populations. A few of the articles constructed predictive nomograms using a panel of biomarkers which require further validation. Challenges to the development of useful markers include different methodology, cancer heterogeneity, and sampling error. These can be overcome by categorizing prognostic factors into particular gene pathways or by supplementing biopsy information with blood or urine-based biomarkers. Conclusion. Though biomarkers based on differential expression offer the potential to improve decision making concerning prostate cancer, further validation of their utility and accuracy at the biopsy level is needed.

Effect of resveratrol on Bcl-2 and VEGF expression in oxygen-induced retinopathy of prematurity

PURPOSE

To explore the effect of resveratrol on B-cell leukemia/lymphoma-2 (Bcl-2) and vascular endothelial growth factor (VEGF) expression in rats with oxygen-induced retinopathy of prematurity (ROP).

METHODS

Seven-day-old Sprague-Dawley rats (N = 60) were randomly assigned to five groups. Group A received normal partial oxygen pressure and groups B, C, D, and E received 75% ± 2% oxygen for 5 days to induce ROP. The rats in groups C, D, and E were intragastrically treated with resveratrol (10, 30, and 60 mg/kg/d, respectively) once daily for 5 days. Rats were killed at 17 days of age and the retina was collected.

RESULTS

Western blot analysis revealed increased Bcl-2 protein expression in group B versus group A. Levels of Bcl-2 decreased with the increase of resveratrol concentration in groups C, D, and E. The optical density of Bcl-2 protein expression in group B was four times higher than that in group A (P < .01). When compared with group B, expression of Bcl-2 and VEGF in groups C, D, and E decreased in a dose-dependent manner. Significant differences in expression of Bcl-2 and VEGF were also noted among the three treatment groups with resveratrol (P < .01). After treatment with resveratrol at 10, 30, and 60 mg/kg/d, the inhibition rate of Bcl-2 expression was 11.1%, 38.1%, and 69.8% and that of VEGF expression was 3.4%, 23.0%, and 43.7%, respectively.

CONCLUSION

Resveratrol can significantly inhibit expression of Bcl-2 and VEGF in the retina of neonatal rats with oxygen-induced ROP. It may provide a protective effect on retinal neovascular diseases, including ROP.

Assessment of the American Joint Committee on Cancer staging (sixth and seventh editions) for clinically localized prostate cancer treated with external beam radiotherapy and comparison with the National Comprehensive Cancer Network risk-stratification method

BACKGROUND

The objective of this study was to compare the prognostic value of the sixth and seventh editions of the American Joint Cancer Committee (AJCC) Cancer Staging Manual and the risk-stratification model of the National Comprehensive Cancer Network (NCCN).

METHODS

Two-thousand four hundred twenty-nine men who received definitive radiotherapy with or without androgen-deprivation therapy (median follow-up, 74 months) were analyzed.

RESULTS

There was a migration of stage II patients to stage I with AJCC seventh edition (stage I increased from 1% to 38%, and stage II decreased from 91% to 55%). One pair-wise comparison (4%) of Kaplan-Meier estimates of biochemical failure, distant metastasis, prostate cancer-specific survival, and overall survival between stages was statistically significant for the AJCC sixth edition. Conversely, 16 of 24 comparisons (67%) were significant for the AJCC seventh edition. With the NCCN risk-stratification model, 9 of 12 comparisons (75%) were significant. Concordance probability estimate (CPE) and standard error (SE) analysis indicated uniform and significant improvement in the predictive power of the AJCC seventh edition versus the sixth edition for all outcomes. CPE ± SE values for the AJCC seventh edition versus the sixth edition were 0.51 ± 0.009 versus 0.59 ± 0.02, respectively, for biochemical failure; 0.54 ± 0.02 versus 0.70 ± 0.05, respectively, for distant metastasis; 0.57 ± 0.009 versus 0.76 ± 0.007, respectively, for prostate cancer-specific survival; and 0.52 ± 0.006 versus 0.57 ± 0.01, respectively, for overall survival. CPE ± SE values for the NCCN model were 0.59 ± 0.02 for biochemical failure, 0.72 ± 0.05 for distant metastasis, 0.80 ± 0.01 for prostate cancer-specific survival, and 0.57 ± 0.01 for overall survival.

CONCLUSIONS

The current results indicated that the seventh edition of the AJCC Cancer Staging Manual is a major improvement over the sixth edition, because it distributes patients better among the stages and is more prognostic. However, the NCCN model was superior to the AJCC seventh edition and remains the preferred method for risk-based clinical management of prostate cancer with radiotherapy.

Comparative effectiveness research for prostate cancer radiation therapy: current status and future directions

Comparative effectiveness research aims to help clinicians, patients and policymakers make informed treatment decisions under real-world conditions. Prostate cancer patients have multiple treatment options, including active surveillance, androgen deprivation therapy, surgery and multiple modalities of radiation therapy. Technological innovations in radiation therapy for prostate cancer have been rapidly adopted into clinical practice despite relatively limited evidence for effectiveness showing the benefit for one modality over another. Comparative effectiveness research has become an essential component of prostate cancer research to help define the benefits, risks and effectiveness of the different radiation therapy modalities currently in use for prostate cancer treatment.

The relationship between p27(kip1) expression and the change of radiosensitivity of esophageal carcinoma cells

OBJECTIVE

Radioresistance is considered the main reason for therapeutic failure in radiotherapy of esophageal carcinoma. However, the underlying mechanisms of radioresistance remain elusive. The purpose of this study was to investigate the relationship between p27(kip1) expression and the change of radiosensitivity of esophageal carcinoma cells.

MATERIAL AND METHODS

Radioresistant cells were gradually isolated by means of repeated gamma-ray irradiation upon esophageal carcinoma cells. The radiosensitivity of established radioresistant cells and parental cells was measured by standard colony-forming assay. Cell cycle was detected by flow cytometry. Western blot method was performed to identify the expression of p27(kip1).

RESULTS

Colony-forming assay showed that the radioresistant cells had obvious radioresistance. Percentage of the radioresistant cells at G(0)/G(1) and G(2)/M phase was significantly decreased, and the percentage of S phase cells was significantly increased compared with the parent cells (p < 0.05). Western blotting revealed that p27(kip1) expression of the radioresistant cells was lower than that of parent cells.

CONCLUSIONS

Our results suggest that cell phase change due to the decrease of p27(kip1) expression is one of the mechanisms of radioresistance in esophageal carcinoma cells.