Neuroendocrine serum tumour markers in hormone-resistant prostate cancer

Limited prognostic role of routine serum markers (AP, CEA, LDH and NSE) in oligorecurrent prostate cancer patients undergoing PSMA-radioguided surgery

INTRODUCTION

We evaluated the prognostic role of pre-salvage prostate-specific membrane antigen-radioguided surgery (PSMA-RGS) serum levels of alkaline phosphatase (AP), carcinoembryonic antigen (CEA), lactate dehydrogenase (LDH), and neuron-specific enolase (NSE).

MATERIALS AND METHODS

Patients who consecutively underwent PSMA-RGS for prostate cancer (PCa) oligorecurrence between January 2019 and January 2022 were selected. Biomarkers were assessed one day before surgery. Cox regression and logistic regression models tested the relationship between biochemical recurrence-free survival (BFS), 6- and 12-month biochemical recurrence (BCR), and several independent variables, including biomarkers.

RESULTS

153 consecutive patients were analyzed. In the univariable Cox regression analysis, none of the biomarkers achieved predictor status (AP: hazard ratio [HR] = 1.03, 95% CI 0.99, 1.01; p = 0.19; CEA: HR = 1.73, 95% CI 0.94, 1.21; p = 0.34; LDH: HR = 1.01, 95% CI 1.00, 1.01; p = 0.05; NSE: HR = 1.02, 95% CI 0.98, 1.06; p = 0.39). The only independent predictor of BFS was the number of positive lesions on PSMA PET (HR = 1.17, 95% CI 1.02, 1.30; p = 0.03). The number of positive lesions was confirmed as independent predictor for BCR within 6 and 12 months (BCR < 6 months: odds ratio [OR] = 1.1, 95% CI 1.0, 1.3; p = 0.04; BCR < 12 months: OR = 1.1, 95% CI 1.0, 1.3; p = 0.04).

CONCLUSION

The assessment of AP, CEA, LDH, and NSE before salvage PSMA-RGS showed no prognostic impact. Further studies are needed to identify possible predictors that will optimize patient selection for salvage PSMA-RGS.

PET/CT and Conventional Imaging for the Assessment of Neuroendocrine Prostate Cancer: A Systematic Review

BACKGROUND

Neuroendocrine prostate cancer (NEPC) is a rare neoplasm, and the role of both conventional imaging (CI) and positron emission tomography/computed tomography (PET/CT) for its assessment has not been clearly evaluated and demonstrated. The aim of this systematic review was to analyze the diagnostic performances of these imaging modalities in this setting.

METHODS

A wide literature search of the PubMed/MEDLINE, Scopus, and Web of Science databases was made to find relevant published articles about the role of CI and PET/CT for the evaluation of NEPC.

RESULTS

13 studies were included in the systematic review. PET/CT imaging with different radiopharmaceuticals has been evaluated in many studies (10) compared to CI (3 studies), which has only a limited role in NEPC. Focusing on PET/CT, a study used [18F]FDG, labeled somatostatin analogs were used in 5 cases, a study used [68Ga]Ga-FAPI-04, [68Ga]Ga-PSMA-11 was evaluated in a single case, and two works used different tracers.

CONCLUSION

Published data on the role of PET/CT for the assessment of NEPC are limited. At present, it is still uncertain which tracer performs best, and although [18F]FDG has been evaluated and seems to offer some advantages in availability and clinical staging, other tracers may be more useful to understand tumor biology or identify targets for subsequent radioligand therapy. Further research is therefore desirable. In contrast, data are still limited to draw a final conclusion on the role and the specific characteristics of CI in this rare form of neoplasm, and therefore, more studies are needed in this setting.

Neuroendocrine Differentiation of Prostate Cancer Is Not Systematically Associated with Increased 18F-FDG Uptake

Neuroendocrine differentiation (NED) of prostate cancer represents an acknowledged predictor of resistant and more aggressive disease. NED can be functionally exploited in vivo using PET/CT imaging with somatostatin analogs radiolabeled with 68Ga. Many previous reports have shown that 18F-FDG PET/CT should also be used in cases such as guiding management, as NED is systematically associated with increased glycolysis. We hereby discuss the case of a metastatic prostate cancer patient in which 68Ga-Dotatoc PET/CT revealed the occurrence of NED with low FDG-avidity.

Treatment-Emergent Neuroendocrine Prostate Cancer: A Clinicopathological and Immunohistochemical Analysis of 94 Cases

Purpose

This study aimed to evaluate the pathological characteristics, immunophenotype, and prognosis of treatment-emergent neuroendocrine prostate cancer (T-NEPC).

Materials and Methods

We collected 231 repeated biopsy specimens of castration-resistant prostate cancer (CRPC) cases between 2008 and 2019. We used histopathological and immunohistochemical evaluations of Synaptophysin (SYN), ChromograninA (CgA), CD56, androgen receptor (AR), and prostate-specific antigen (PSA) to screen out T-NEPC cases. Multivariate analyses were performed to identify factors in the prognosis of T-NEPC. Further, the results were verified in the Surveillance, Epidemiology, and End Results (SEER) program.

Results

Among the 231 CRPC cases, 94 (40.7%) cases were T-NEPC. T-NEPC were more likely to present with negative immunohistochemistry for AR (30.9%) and PSA (47.9%) than that of CRPC (8.8% and 17.5%, respectively). Kaplan-Meier analysis revealed that patients with T-NEPC (median overall survival [OS]: 17.6 months, 95% CI: 15.3-19.9 months) had significantly worse survival compared with usual CRPC patients (median OS: 23.6 months, 95% CI: 21.3-25.9 months, log-rank P = 0.001), especially in metastasis cases (median OS: 15.7 months, 95% CI: 13.3-18.0 months) and patients with small cell carcinoma component (median OS: 9.7 months, 95% CI: 8.2-11.2 months). Prostate adenocarcinoma with diffuse NE differentiation (median OS: 18.8 months, 95% CI: 15.3-22.3 months) had poor outcome than those with usual CRPC (P = 0.027), while there was no significant change in the focal NE differentiation (median OS: 22.9 months, 95% CI: 18.1-27.7 months, P = 0.136). In the unadjusted model, an excess risk of overall death was observed in T-NEPC with PSA negative (HR = 2.86, 95% CI = 1.39-6.73). Among 476 NEPC cases in the SEER database from 2004 to 2017, we observed a higher hazard of overall death in patients aged 65 years and older (HR = 1.35, 95% CI = 1.08-1.69), patients with PSA ≤ 2.5 ng/ml (HR = 1.90, 95%CI = 1.44-2.52), patients with PSA 2.6-4.0 ng/ml (HR = 2.03, 95%CI = 1.38-2.99), stage IV tumor (HR = 2.13, 95%CI = 1.47-3.08) and other races (HR = 1.85, 95%CI = 1.17-2.94) in total NEPC, adjusting for confounders. Similar hazard ratios were observed in pure NEPC, while there was no significant results among prostate adenocarcinoma with NE differentiation tumors.

Conclusion

T-NEPC was associated with an unfavorable prognosis, negative immunohistochemistry for PSA in T-NEPC and serum PSA level ≤ 4 ng/ml had a worse prognosis. Urologists and pathologists should recognize the importance of the second biopsy in CRPC to avoid unnecessary diagnosis and treatment delays.

Neuroendocrine and Aggressive-Variant Prostate Cancer

In prostate cancer, neuroendocrine (NE) differentiation may rarely present de novo or more frequently arises following hormonal therapy in patients with castration-resistant prostate cancer (CRPC). Its distinct phenotype is characterized by an aggressive clinical course, lack of responsiveness to hormonal therapies and poor prognosis. Importantly, a subset of CRPC patients exhibits an aggressive-variant disease with very similar clinical and molecular characteristics to small-cell prostate cancer (SCPC) even though tumors do not have NE differentiation. This aggressive-variant prostate cancer (AVPC) also shares the sensitivity of SCPC to platinum-based chemotherapy albeit with short-lived clinical benefit. As optimal treatment strategies for AVPC remain elusive, currently ongoing research efforts aim to enhance our understanding of the biology of this disease entity and improve treatment outcomes for our patients. This review is an overview of our current knowledge on prostate cancer with NE differentiation and AVPC, with a focus on their clinical characteristics and management, including available as well as experimental therapeutic strategies.

Treatment-emergent neuroendocrine prostate cancer: molecularly driven clinical guidelines

An increasingly recognized mechanism of prostate cancer resistance is the transdifferentiation from adenocarcinoma to treatment-emergent neuroendocrine prostate cancer (t-NEPC), an extremely aggressive malignancy. The incidence of t-NEPC has been increasing in recent years, in part due to novel treatments that target the androgen receptor pathway. While clinicians historically had very few options for t-NEPC detection and treatment, recent research has uncovered key diagnostic tools and therapeutic targets that can be translated into improved patient care. In this article, we will outline the clinical features of t-NEPC and its molecular pathogenesis. Importantly, we will also discuss recently uncovered molecularly based strategies aimed at improving the diagnosis and treatment of t-NEPC. Finally, we will propose a unified algorithm that integrates clinical and molecular information for the clinical management of t-NEPC.

Serum chromogranin-A-based prognosis in metastatic castration-resistant prostate cancer

OBJECTIVE

To determine the prognostic value of serum chromogranin-A (CGA) in a two-cohort study of men with metastatic castrate resistant prostate cancer (mCRPC) and to compare with circulating tumor cells (CTCs)-based prognosis.

PATIENTS AND METHODS

A two-cohort-based evaluation for serum CGA for prognostication in CRPC stage was performed using a screening cohort of 256 men with mCRPC and an independent validation cohort of 92 men with mCRPC. In both cohorts, men receiving proton pump inhibitors and those with non-castrate levels of testosterone (>50 ng/dl) were excluded. Serum CGA was measured in a homogeneous automated immunofluorescent assay using time-resolved amplified cryptate emission. In the validation cohort, CTC enumeration was also performed using the FDA-cleared CELLSEARCH® CTC test. Cox proportional hazard regression models were used for prognostic association of serum CGA and CTC counts with overall survival.

RESULTS

In the screening cohort, 200 men were eligible for analysis. The median serum CGA was 100.3 ng/mL (interquartile range: 67-161.3) and 34/200 were above the reference range. In the subset of men with Gleason scores ≥ 8, elevated CGA was associated with shorter overall survival [hazard ratio (HR) 2.19, p = 0.017]. In the validation cohort for 71 men eligible for analysis, the median serum CGA was 90 ng/mL (interquartile range: 55-156) and 31/71 patients had an elevated CGA. 51% of patients had a Gleason score ≥ 8 and 66/71 patients had CTCs enumerated with 26/66 with a CTC count ≥ 5 per 7.5 ml blood sample (unfavorable). Both elevated serum CGA (HR: 1.91, p = 0.043) and unfavorable CTC counts (HR: 2.97, p = 0.0012) were adversely associated with overall survival and patients with ≥ 5 CTCs and elevated serum CGA had the shortest overall survival (HR: 3.76, p = 0.008).

CONCLUSION

Elevated serum CGA was negatively associated with OS in men with mCRPC. Serum CGA represents a prognostic biomarker that may complement CTC enumeration.

The role of serum neuron-specific enolase in patients with prostate cancer: a systematic review of the recent literature

In this systematic review, we evaluated the value of serum concentrations of neuron-specific enolase (NSE) in patients with prostate cancer (PCa) in order to clarify the possible role of NSE in the diagnosis, management, treatment and monitoring of PCa. A comprehensive search of the recent literature was conducted to find relevant data on the role of NSE in PCa. Two hundred and eighty-two records were revealed, and 19 articles including 1,772 patients with PCa (either confirmed or suspected) were selected. After reviewing the articles, the major result was that elevated serum NSE appears to correlate with prognosis in advanced PCa, particularly in patients with progressive and metastatic castration-resistant PCa. Based on the existing literature, the role of serum NSE in PCa patients should be further evaluated.

Neuroendocrine Differentiation in Prostatic Malignancy

Neuroendocrine differentiation in prostatic malignancy is receiving considerable attention; this occurs commonly as a “focal” histological variant and, most rarely, in the form of small cell carcinoma (“oat cell carcinoma”) and carcinoid tumor. In prostate cancer, neuroendocrine differentiation may be the response to androgen deprivation and neuroendocrine products, either biogenic amines or peptides, have been shown to stimulate proliferation of androgen-ablation refractory cancer cells. Serum chromogranins, neuron-specific enolase and other neuroendocrine products as well as 111-In-chromogranin A “three step” immunoscintigraphy and somatostatin-receptor scintigraphy may be useful for predicting tumor behaviour and patient prognosis.

Several of the neuroendocrine products, particularly somatostatin analogues, are candidates for new therapeutic approaches. The paper aims to outline the advances in this field on the basis of the review of the literature.

The Possible Role of Chromogranin A as a Prognostic Factor in Organ-Confined Prostate Cancer

The clinical significance of neuroendocrine differentiation in patients who have undergone surgery for localized prostate cancer is still unclear. The aims of this study were to assess the relationship between serum neuroendocrine markers and well-known prognostic factors in prostate cancer (pathological staging, definitive Gleason score and serum PSA) and to search for correlations between serum chromogranin A (CgA) levels and pathological findings.

Forty-one consecutive patients who had undergone radical retropubic prostatectomy for clinically localized prostate cancer were evaluated. Serum PSA, CgA and neuron-specific enolase were measured immediately before surgery. Twenty-six surgical specimens were phenotypically and immunohistochemically evaluated using an antibody against CgA.

Significant correlations were found between serum CgA, pathological staging and Gleason score (p=0.049 and p=0.038, respectively). Serum CgA did not correlate with PSA, patient age, or immunohistochemical findings. There was a significant correlation between positive immunohistochemical CgA staining and Gleason score (p=0.014).

An increase in serum CgA levels, independent of PSA values, might be the expression of pathologically more advanced tumor stage and higher Gleason score; this could help to identify a high-risk patient group eligible for adjuvant therapy.

Influence of abiraterone acetate on neuroendocrine differentiation in chemotherapy-naive metastatic castration-resistant prostate cancer

BACKGROUND

To determine the influence of abiraterone Acetate (AA) on neuroendocrine differentiation (NED) in patients with chemotherapy-naive metastatic castration-resistant prostate cancer (mCRPC).

METHODS

We conducted an analysis in 115 chemotherapy-naïve mCRPC patients who would be treated with chemotherapy. The serum levels of chromogranin A (CgA), neurone-specific enolase (NSE) were measured in 67 mCRPC patients without AA treatment and 48 patients after the failure of AA treatment, in which these markers were also measured in 34 patients before and after 6 months of AA treatment. Comparative t-test was used to evaluate the serial changes of serum NED markers during AA treatment and univariate and multivariate analyses were performed to test the influence of AA treatment on NED.

RESULTS

Serum CgA were NSE were evaluated to be above the upper limit of normal (ULN) in 56 (48.7%) and 29 (25.2%) patients before chemotherapy. In 34 patients with serial evaluation, serum CgA level of 14 patients and NSE of 14 patients increased after the failure of AA treatment. There was no significant difference of NED markers (CgA or NSE variation (P = 0.243) between at baseline and after the failure of AA treatment. Compared with the CgA elevation group in the first 6 months of AA treatment and baseline supranormal CgA group, the CgA decline group, and baseline normal CgA group has a much longer median PSA PFS (14.34 vs 10.00 months, P < 0.001, and 14.23 vs 10.30 months, P = 0.02) and rPFS, respectively (18.33 vs 11.37 months, P < 0.001, and 17.10 vs 12.07 months, P = 0.03). In logistic univariate analysis, AA treatment and its duration were not independent factors influencing NED.

CONCLUSIONS

We hypothesized that AA might not significantly lead to progression of NED of mCRPC in general. Furthermore, we found there was heterogeneity in changes of NED markers in different mCRPC patients during AA treatment. Serial CgA and NSE evaluation might help clinicians guide clinical treatment of mCRPC patients.

Up-Regulated Expression of LAMP2 and Autophagy Activity during Neuroendocrine Differentiation of Prostate Cancer LNCaP Cells

Neuroendocrine (NE) prostate cancer (PCa) is a highly aggressive subtype of prostate cancer associated with resistance to androgen ablation therapy. In this study, we used LNCaP prostate cancer cells cultured in a serum-free medium for 6 days as a NE model of prostate cancer. Serum deprivation increased the expression of NE markers such as neuron-specific enolase (NSE) and βIII tubulin (βIII tub) and decreased the expression of the androgen receptor protein in LNCaP cells. Using cDNA microarrays, we compared gene expression profiles of NE cells and non-differentiated LNCaP cells. We identified up-regulation of 155 genes, among them LAMP2, a lysosomal membrane protein involved in lysosomal stability and autophagy. We then confirmed up-regulation of LAMP2 in NE cells by qRT-PCR, Western blot and confocal microscopy assays, showing that mRNA up-regulation correlated with increased levels of LAMP2 protein. Subsequently, we determined autophagy activity in NE cells by assessing the protein levels of SQSTM/p62 and LC3 by Western blot and LC3 and Atg5 mRNAs content by qRT-PCR. The decreased levels of SQSTM/p62 was accompanied by an enhanced expression of LC3 and ATG5, suggesting activation of autophagy in NE cells. Blockage of autophagy with 1μM AKT inhibitor IV, or by silencing Beclin 1 and Atg5, prevented NE cell differentiation, as revealed by decreased levels of the NE markers. In addition, AKT inhibitor IV as well as Beclin1 and Atg5 kwockdown attenuated LAMP2 expression in NE cells. On the other hand, LAMP2 knockdown by siRNA led to a marked blockage of autophagy, prevention of NE differentiation and decrease of cell survival. Taken together, these results suggest that LAMP2 overexpression assists NE differentiation of LNCaP cells induced by serum deprivation and facilitates autophagy activity in order to attain the NE phenotype and cell survival. LAMP2 could thus be a potential biomarker and potential target for NE prostate cancer.

Chromogranin A and neurone-specific enolase serum levels as predictors of treatment outcome in patients with metastatic castration-resistant prostate cancer undergoing abiraterone therapy

OBJECTIVE

To determine the impact of elevated neuroendocrine serum markers on treatment outcome in patients with metastatic castration-resistant prostate cancer (mCRPC) undergoing treatment with abiraterone in a post-chemotherapy setting.

PATIENTS AND METHOD

Chromogranin A (CGa) and neurone-specific enolase (NSE) were determined in serum drawn before treatment with abiraterone from 45 patients with mCRPC. Outcome measures were overall survival (OS), prostate-specific antigen (PSA) response defined by a PSA level decline of ≥50%, PSA progression-free survival (PSA-PFS), and clinical or radiographic PFS.

RESULTS

The CGa and NSE serum levels did not correlate (P = 0.6). Patients were stratified in to low- (nine patients), intermediate- (18) or high-risk (18) groups according to elevation of none, one, or both neuroendocrine markers, respectively. The risk groups correlated with decreasing median OS (median OS not reached vs 15.3 vs 6.6 months; P < 0.001), decreasing median clinical or radiographic PFS (8.3 vs 4.4 vs 2.7 months; P = 0.001) and decreasing median PSA-PFS (12.0 vs 3.2 vs 2.7 months; P = 0.012). In multivariate Cox regression analysis the combination of CGa and NSE (≥1 marker positive vs both markers negative) remained significant predictors of OS, clinical or radiographic PFS, and PSA-PFS. We did not observe a correlation with PSA response (63% vs 35% vs 31%; P = 0.2).

CONCLUSION

Chromogranin A and NSE did not predict PSA response in patients with mCRPC treated with abiraterone. However, we observed a correlation with shorter PSA-PFS, clinical or radiographic PFS, and OS. This might be due to an elevated risk of developing resistance under abiraterone treatment related to neuroendocrine differentiation.

Prostate cancer and neuroendocrine differentiation: more neuronal, less endocrine?

Neuroendocrine differentiation (NED) marks a structural and functional feature of certain cancers, including prostate cancer (PCa), whereby the malignant tissue contains a significant proportion of cells displaying neuronal, endocrine, or mixed features. NED cells produce, and can secrete, a cocktail of mediators commonly encountered in the nervous system, which may stimulate and coordinate cancer growth. In PCa, NED appears during advanced stages, subsequent to treatment, and accompanies treatment resistance and poor prognosis. However, the term “neuroendocrine” in this context is intrinsically vague. This article seeks to provide a framework on which a unified view of NED might emerge. First, we review the mutually beneficial interplay between PCa and neural structures, mainly supported by cell biology experiments and neurological conditions. Next, we address the correlations between PCa and neural functions, as described in the literature. Based upon the integration of clinical and basic observations, we suggest that it is legitimate to seek for true neural differentiation, or neuromimicry, in cancer progression, most notably in PCa cells exhibiting what is commonly described as NED.

Evolving treatment paradigms for locally advanced and metastatic prostate cancer

While men with early stage prostate cancer typically enjoy long-term survival after definitive management, for those who present with locally advanced or metastatic disease, survival is compromised. Multimodality therapy can prolong survival in these patients, with state-of-the-art options including intensity-modulated radiation or brachytherapy in conjunction with androgen ablation, adjuvant androgen ablation and/or chemotherapy with radical retropubic prostatectomy. In addition, novel biological therapies are being explored to target the unique molecular changes in prostate cancer cells and their interactions with the microenvironment. With these advances the outlook will undoubtedly improve, even for patients presenting with advanced disease. Careful application of these emerging therapies to a select group of prostate cancer patients most likely to obtain benefit from them is the challenge for urologists, medical oncologists and radiation oncologists for the future.

Neuroendocrine-derived peptides promote prostate cancer cell survival through activation of IGF-1R signaling

BACKGROUND

Neuroendocrine (NE) cells promote the progression of prostate cancer to a castration-resistant state through the production of paracrine growth factors. We have demonstrated this principle using in vitro and in vivo proliferative endpoints; however, the contributions of NE-derived pro-survival factors and anti-apoptosis to this phenomenon have not been thoroughly investigated.

METHODS

Here, we utilized conditioned-medium (CM) from LNCaP cells, engineered to undergo NE differentiation, and examined its effects on PC3 and LNCaP cell survival.

RESULTS

Statistically significant changes in clonogenic survival, Annexin V staining, PARP cleavage and trypan blue positivity of approximately twofold were observed in the presence of NE-derived CM relative to control-CM for both LNCaP and PC3 cells. These changes were partially abrogated by antagonists of the neuropeptides neurotensin, bombesin, and PTHrP. Selective inhibitors of IGF-1R, EGFR or Src caused significant and nearly complete blockade of prostate cancer cell survival due to NE secretions. Similar increases in cell survival were observed for LNCaP or PC3 cells treated with NE-derived medium in the presence of docetaxel. Increased phosphorylation of IGF-1R, following treatment with NE-derived medium, was accompanied by decreased protein tyrosine phosphatase, receptor type F (PTPRF) mRNA, and protein levels. Overexpression of PTPRF decreased cell survival, the amplitude and duration of IGF-1R phosphorylation, and enhanced PARP cleavage in the presence of NE-derived medium.

CONCLUSIONS

These data support the hypothesis that NE-derived factors act upon prostate cancer cells to stimulate pro-survival signaling and describe a novel mechanism of cross-talk between NE-derived factors and IGF-1R, mediated in part by PTPRF.

Small cell carcinoma of the prostate after high-dose-rate brachytherapy for low-risk prostatic adenocarcinoma

In the present study, we describe an 80-year-old patient who developed prostatic small cell carcinoma (SCC) following high-dose-rate brachytherapy (HDR-BT) for low-risk prostatic adenocarcinoma. The patient received one implant of Ir-192 and 7 fractions of 6.5 Gy within 3.5 days, for a total prescribed dose of 45.5 Gy. A total of 27 months after HDR-BT, the patient complained of difficulty in urinating. His serum prostate-specific antigen (PSA) levels were 3.2 ng/ml. Systemic examination revealed an enlargement of the prostate, urethral stenosis, pelvic lymph node swelling and multiple lung and bone lesions. His serum neuron-specific enolase (NSE) levels were elevated to 120 ng/ml. A prostate needle biopsy was performed for pathological examination. Histologically, there were tumor cells with hyperchromatic nuclei and scant cytoplasm showing a solid or trabecular growth pattern. Immunohistochemically, they were positive for AE1/AE3, CD56 and synaptophysin, and negative for PSA, PAP and CD57. These findings are consistent with SCC of the prostate. A review of the prostate needle biopsy specimen prior to HDR-BT did not reveal any tumor cells positive for chromogranin A, nor synaptophysin. The final diagnosis was SCC of the prostate with local progression, with lung, lymph node and bone metastases. Three cycles of etoposide/cisplatin (EP) were administered. A greater than 50% decrease in the serum NSE levels was observed. However, there was no objective response. Due to the deterioration of the patient's general condition, EP was discontinued. One month later, his serum NSE showed a rapid increase to 210 ng/ml with aggressive local progression and the patient succumbed to the disease 5.5 months after the start of EP therapy.

The effects of short-term genistein intervention on prostate biomarker expression in patients with localised prostate cancer before radical prostatectomy

Nutritionally relevant levels of genistein, the predominant isoflavone in soyabean associated with lower risk of prostate cancer (PCa), may modulate the expression of prostate tissue biomarkers associated with cancer prediction and progression. A phase 2 placebo-controlled, randomised, double-blind clinical trial was conducted in forty-seven Norwegian patients before prostatectomy. Intervention was 30 mg genistein or placebo capsules daily for 3-6 weeks. Luminal cells from malignant and benign glands were isolated with laser capture microdissection and the mRNA levels of androgen-related biomarkers (androgen receptor, NK3 homeobox 1, kallikrein-related peptide 4 (KLK4)) and cell cycle-related genes (p21 Waf1/Cip1 , p27 Kip1 , p53) were analysed with real-time semiquantitative PCR. Immunohistochemistry of androgen-, cell cycle-, proliferative- (Ki67 nuclear antigen), apoptotic- (B-cell CLL/lymphoma 2 (BCL-2) and BCL-2-associated X protein) and neuroendocrine differentiation-related biomarkers (neuron-specific enolase and cytoplasmic chromogranin A) was performed using tissue microarrays containing normal, Gleason grade 3 and grade 4 prostate tissues. There were no significant effects by genistein intervention on proliferation-, cell cycle-, apoptosis- or neuroendocrine biomarkers. Genistein intervention, however, significantly reduced the mRNA level of KLK4 in tumour cells (P = 0·033) and there was a non-significant reduction in androgen and cell cycle-related biomarkers, except for p27Kip1, whose expression in the nuclear compartment was increased. Genistein intervention modulated the expression of several biomarkers which may be related to PCa prediction and progression. The present study supports genistein as a chemopreventive agent in PCa. Further investigation is warranted in larger and longer-duration studies.

Factors implicated in radiation therapy failure and radiosensitization of prostate cancer

Tissue markers may be helpful in enhancing prediction of radiation therapy (RT) failure of prostate cancer (PCa). Among the various biomarkers tested in Phase III randomized trials conducted by the Radiation Therapy Oncology Group, p16, Ki-67, MDM2, COX-2, and PKA yielded the most robust data in predicting RT failure. Other pathways involved in RT failure are also implicated in the development of castration-resistant PCa, including the hypersensitive androgen receptor, EGFR, VEGF-R, and PI3K/Akt. Most of them are detectable in PCa tissue even at the time of initial diagnosis. Emerging evidence suggests that RT failure of PCa results from a multifactorial and heterogeneous disease process. A number of tissue markers are available to identify patients at high risk to fail RT. Some of these markers have the promise to be targeted by drugs currently available to enhance the efficacy of RT and delay disease progression.

Incidence of high chromogranin A serum levels in patients with non metastatic prostate adenocarcinoma

Background

ChromograninA in prostate carcinoma (PC) indicate NE differentiation. This tumour is more aggressive and resistant to hormone therapy.

Patients and methods

We analyzed the incidence of pre-operative ChromograninA serum levels in non metastatic PC patients. Serum PSA and ChromograninA were analyzed before treatment. Clinicopathological parameters were evaluated in relation to serum ChromograninA. 486 patients were enrolled.

Results

We found 352 pT2 and 134 pT3. 21 patients were N+. 278 patients had Gleason score levels <7; 173 patients had levels = 7 (122 were 3+4 and 51 4+3); and 35 patients with levels >7. Median PSA pre-operative level was 7.61 ng/ml. PSA was significantly associated with pT stage (pT2 with PSA abnormal 23.6% vs pT3 48.5%, p < 0.0001) and with a Gleason score (PSA abnormal 60% in the Gleason score was >7 vs 29.5% in the Gleason score = 7 vs 27.3% in the Gleason score <7, p < 0.0001). In 114 patients pre-operative ChromograninA levels were elevated (23.5%). Serum ChromograninA levels had no significant association with PSA (p = 0.44) and pT stage (p = 0.89). abnormal ChromograninA levels increased from a Gleason score of <7 (25.5%) to >7 (31.4%) (p = 0.12). The serum ChromograninA levels in the two groups of patients were subdivided before and after 2005 on the basis of different used assays, showing no correlation with serum ChromograninA and other parameters.

Conclusions

This study showed that ChromograninA levels correlated to NE differentiation and possible aggressiveness of PC. Pre-operative circulating ChromograninA could complement PSA in selecting more aggressive PC cases, particularly in the presence of a higher Gleason score. Complementary information is provided by the absence of a correlation between serum ChromograninA and PSA levels.

The neuroendocrine-derived peptide parathyroid hormone-related protein promotes prostate cancer cell growth by stabilizing the androgen receptor

During progression to an androgen-independent state following androgen ablation therapy, prostate cancer cells continue to express the androgen receptor (AR) and androgen-regulated genes, indicating that AR is critical for the proliferation of hormone-refractory prostate cancer cells. Multiple mechanisms have been proposed for the development of AR-dependent hormone-refractory disease, including changes in expression of AR coregulatory proteins, AR mutation, growth factor-mediated activation of AR, and AR protein up-regulation. The most prominent of these progressive changes is the up-regulation of AR that occurs in >90% of prostate cancers. A common feature of the most aggressive hormone-refractory prostate cancers is the accumulation of cells with neuroendocrine characteristics that produce paracrine factors and may provide a novel mechanism for the regulation of AR during advanced stages of the disease. In this study, we show that neuroendocrine-derived parathyroid hormone-related protein (PTHrP)-mediated signaling through the epidermal growth factor receptor (EGFR) and Src pathways contributes to the phenotype of advanced prostate cancer by reducing AR protein turnover. PTHrP-induced accumulation of AR depended on the activity of Src and EGFR and consequent phosphorylation of the AR on Tyr(534). PTHrP-induced tyrosine phosphorylation of AR resulted in reduced AR ubiquitination and interaction with the ubiquitin ligase COOH terminus of Hsp70-interacting protein. These events result in increased accumulation of AR and thus enhanced growth of prostate cancer cells at low levels of androgen.

p19(ras) Represses proliferation of non-small cell lung cancer possibly through interaction with Neuron-Specific Enolase (NSE)

p19(ras) is an alternative splicing product of the proto-oncogene c-H-ras pre-mRNA. In this study, we identified a novel p19(ras)-binding protein, Neuron-Specific Enolase (NSE), using the yeast two-hybrid method. NSE is one of the enolase families that convert 2-phospho-d-glycerate (PGA) to phosphoenolpyruvate (PEP) in the glycolysis pathway. In both endogenous and over-expressed systems, we confirmed interactions between p19(ras) and NSE via co-immunoprecipitation assay. We also identified the interaction region of p19(ras), which is required for binding with NSE. When full-length p19(ras) and C-terminal region are bound to NSE, it inhibits the enzymatic activity of NSE. Furthermore, p19(ras) interacted with Enolase alpha (Enoalpha) and repressed its enzymatic activity in vitro. p19(ras) repressed lung cancer cell proliferation mostly increased by NSE in H1299 cells. Taken together, these results suggest that p19(ras) is a novel regulator to suppress cell proliferation in lung cancer through the interaction with NSE.

Neuroendocrine differentiation of localized prostate cancer during endocrine therapy

A 74-year-old male was treated with endocrine therapy for localized prostate cancer. After 25 months he complained of a swollen neck, and was diagnosed with prostate cancer with lymph node metastasis of neuroendocrine differentiation. Neuroendocrine differentiation without elevation of conventional tumor markers is rare during the initial recurrent course of localized prostate cancer.

Neuroendocrine differentiation in the progression of prostate cancer

Neuroendocrine (NE) cells originally exist in the normal prostate acini and duct, regulating prostatic growth, differentiation and secretion. Clusters of malignant NE cells are found in most prostate cancer (PCa) cases. NE differentiation (NED) is the basic character of the prostate, either benign or malignant. NE cells hold certain peptide hormones or pro-hormones, which affect the target cells by endocrine, paracrine, autocrine and neuroendocrine transmission in an androgen-independent fashion due to the lack of androgen receptor. NED is accessed by immunohistochemical staining or measurement of serum levels of NE markers. The extent of NED is associated with progression and prognosis of PCa. Chromogranin A (CGA) is the most important NE marker. In metastatic PCa, pretreatment serum CGA levels can be a predictor for progression and survival after endocrine therapy. It is recommended to measure longitudinal change in serum CGA. The NE pathway can also be a therapeutic target.

The impact of diet and micronutrient supplements on the expression of neuroendocrine markers in murine Lady transgenic prostate

BACKGROUND

Neuroendocrine (NE) differentiation (NED) in prostate cancer (PCa) is associated with morbidity and death; however, the underlying cause(s) promoting NED in PCa have yet to be determined. In this study, we examined the effect of both diet and micronutrient supplementation on the expression of NE markers using the Lady (12T-10) transgenic model of PCa. Lady (12T-10) transgenic animals develop advanced adenocarcinoma with NE characteristics that exhibits metastases in approximately 80% of cases. In this model a high fat diet has been shown to increase the severity of disease, while the use of micronutrients can inhibit this progression.

METHODS

In this study we used immunohistochemical analysis to determine expression of the NE markers: chromogranin A (CgA), neuron-specific enolase (NSE), bombesin, parathyroid hormone-related peptide (PTHrP), neurotensin and serotonin in prostates of PCa-bearing Lady (12T-10) mice.

RESULTS

High fat diet was correlated with significantly elevated expression of CgA and serotonin in prostate tissue of Lady (12T-10) mice. Addition of micronutrients to the control and high fat diet reproducibly elevated PTHrP and bombesin expression and suppressed NSE expression, while prostate tissue from the control diet supplemented with micronutrients exhibited significantly lower numbers of calcitonin- and neurotensin-positive cells.

CONCLUSIONS

These results highlight the importance of dietary control in management of disease and identify differential changes in NE marker expression, which may be diagnostically viable in monitoring the impact of therapies on disease status.

Neuroendocrine differentiation in prostate cancer: from lab to bedside

OBJECTIVES

To discuss the current knowledge on induction, production, sustenance and promotion of neuroendocrine differentiation in human prostate cancer.

METHODS

Review of the literature using PubMed search and scientific journal publications.

RESULTS

Morphological evidence explains some functional relationship between neuroendocrine and neoplastic surrounding cells. Transdifferentiation phenomenon and new biochemical pathways could be included in the development of androgen independence and prostate cancer progression.

CONCLUSION

Multiple evidence seems to confirm that a synergistic functional network between epithelial PSA secretory cells and neuroendocrine intraprostatic system is the main trigger for the induction and sustenance of neuroendocrine differentiation. The development of new antineoplastic molecules should consider the multiple interference of the intercellular network.

Androgen-independent growth and tumorigenesis of prostate cancer cells are enhanced by the presence of PKA-differentiated neuroendocrine cells

The neuroendocrine status of prostatic adenocarcinomas is considered a prognostic indicator for development of aggressive, androgen-independent disease. Neuroendocrine-like cells are thought to function by providing growth and survival signals to surrounding tumor cells, particularly following androgen ablation therapy. To test this hypothesis directly, LNCaP cells were engineered to inducibly express a constitutively activated form of the cyclic AMP-dependent protein kinase A catalytic subunit (caPKA), which was previously found upon transient transfection to be sufficient for acquisition of neuroendocrine-like characteristics and loss of mitotic activity. Clonal cells that inducibly expressed caPKA enhanced the growth of prostate tumor cells in anchorage-dependent and anchorage-independent in vitro assays as well as the growth of prostate tumor xenografts in vivo, with the greatest effects seen under conditions of androgen deprivation. These results suggest that neuroendocrine-like cells of prostatic tumors have the potential to enhance androgen-independent tumor growth in a paracrine manner, thereby contributing to progression of the disease.

Valproic acid induces neuroendocrine differentiation and UGT2B7 up-regulation in human prostate carcinoma cell line

Prostate cancer originates as an androgen-dependent hyperproliferation of the epithelial cells of the gland and it evolves in an androgen-independent, highly aggressive cancer for which no successful therapy is available to date. Neuroendocrine (NE) differentiation plays an important role in the progression of prostate cancer to an androgen-independent state with profound impact on prostate cancer (CaP) therapies. Actually, new approaches on treating advanced prostate cancer are focused on modulators of epigenetic transcriptional regulation. A new class of antitumoral agents is emerging: histone deacetylase (HDAC) inhibitors are interesting for their ability to arrest cell growth, to induce cell differentiation, and in some cases, to induce apoptosis of cancer cells. We studied the effect of valproic acid (VPA), an inhibitor of HDAC, in the human prostate androgen-dependent cancer cell line LNCaP. We observed that VPA promotes neuroendocrine-like differentiation associated with an increase in the expression of neuron-specific enolase, a decrease in prostate-specific antigen, and a down-regulation of androgen receptor protein, suggesting a modulation in the responsiveness to androgen therapy. Furthermore, selective gene expression profiling using a low-density microarray showed that VPA was able to modulate the expression of different androgen metabolism genes. We observed a down-regulation of androgen receptor coregulator (ARA24) and prostate-specific antigen, and an up-regulation of some of the UDP-glucuronosyltransferases (UGT2B11 and UGT2B7) implicated in catabolism of dihydrotestosterone (DHT) was detected. Even though UGT2B7 has only about one-tenth to one-hundredth the activity of UGT2B15 and 2B17 toward active androgens and we did not found any modulation in gene expression of these enzymes, it can be hypothesized that VPA might enhance DHT catabolism in this in vitro model and induces NE differentiation. Our data seem to raise concern about CaP treatment with VPA.

Auto-antibodies in prostate cancer: humoral immune response to antigenic determinants coded by the differentially expressed transcripts FLJ23438 and VAMP3

BACKGROUND

Here we evaluate auto-antibody response against two potential antigenic determinants of genes highly expressed in low Gleason Score prostate cancer (PC) tumor samples, namely FLJ23438 and VAMP3.

METHODS

RT-PCR assays were used to analyze mRNA expression profiles of FLJ23438 and VAMP3 transcripts. The auto-antibody response against FLJ23438 and VAMP3 recombinant proteins was tested by immunoblot assays using PC, benign prostate hyperplasia (BPH), healthy donors (HD), and other human cancers plasma samples.

RESULTS

Our data showed that 37% (10/27) and 7.4% (2/27) of PC plasma samples presented auto-antibodies against FLJ23438 and VAMP3, respectively. Only 8.3% (1/12) of BPH plasma samples were reactive for both auto-antibodies, while none (0/12) of HD plasma samples tested were reactive.

CONCLUSIONS

The prevalence of 37% of positive PC plasma samples for anti-FLJ23438 antibodies suggests that humoral immune response against this antigenic determinant could be a potential serum marker for this cancer.

The chromogranin-A (CgA) in prostate cancer

Prostate cancer is one of the most frequent tumors in men. The neuroendocrine differentiation in prostate cancer has become more widely recognized and has attracted considerable attention as a potentially new finding with major diagnostic, prognostic and therapeutic implications. We investigated the role of the serum concentrations of CgA in a group of 57 patients with prostate cancer and in 61 elderly subjects with benign prostate hyperplasia (BPH). Neuron-specific enolase (NSE) is the most frequently employed marker to detect neuroendocrine features. Serum prostate-specific antigen (PSA), CgA and NSE levels were determined. Comparing prostate cancer group versus BPH group, the CgA level difference was 63.00 ng/ml (p<0.0001) and the PSA level difference was 50.86 mcg/ml (p<0.0001). Between prostate cancer group and control group the CgA level difference was 94.3 ng/ml (p<0.0001), the PSA level difference was 52.91 mcg/ml (p<0.0001), and the NSE level difference was 1.34 microg/l (p<0.0001). Patients with higher CgA levels had poorer prognosis and survival, compared to those with lower CgA levels. These results support the concept that serum CgA level determination before treatment is a potential prognostic factor for prostate cancer.

[Neuroendocrine differentiation in prostate cancer: an unrecognized and therapy resistant phenotype]

Neuroendocrine (NE) differentiation frequently occurs in common prostatic malignancies but usually escapes pathological and clinical detection. The present review focuses on biological properties of NE tumor cells making them resistant to androgen deprivation and radiation therapy. Recent data have shown that NE prostate cancer cells (as defined by the most commonly used endocrine marker chromogranin A) are arrested in the G0-phase of the cell cycle and do not undergo apoptosis. This particular phenotype consistently lacks the nuclear androgen receptor in both benign and malignant conditions but produces a series of hormonal growth factors exerting mitogenic stimuli on adjacent, exocrine tumor cells. Neoplastic NE cells devoid of the nuclear androgen receptor constitute an androgen-insensitive cell population in prostate cancer. The absence of proliferative and apoptotic activity makes NE tumor cells particularly resistant towards cytotoxic drugs and radiation therapy. Pathological and clinical detection of NE features is recommended for all prostate cancer patients for whom radiation therapy and androgen deprivation is being considered.

Neuroserpin (PI-12) is upregulated in high-grade prostate cancer and is associated with survival

We carried out Genechip analysis using prostate cancer and non-malignant tissue to identify specific genes related to prostate cancer. We focused on neuroserpin (PI-12), which has been identified as one of the genes with high expression in prostate cancer. We analyzed the relationship between its expression pattern and clinical characteristics. Prostate cancer and normal prostate tissue were analyzed by Affymetrix GeneChip technology. We carried out real-time quantitative PCR on a total of 102 specimens: 45 of normal prostate, 45 of previously untreated prostate cancer (constituting 45 pairs of samples obtained at radical prostatectomy, with each pair dissected from the same prostate specimen) and 12 of recurrent hormone refractory prostate cancer (HRPC). Results showed that the neuroserpin gene was more highly expressed in prostate cancer than in normal prostate tissue. Neuroserpin expression in untreated prostate cancer was significantly higher than that in normal prostate. In HRPC it was significantly higher than that in untreated prostate cancer and normal prostate. In untreated prostate cancer, neuroserpin expression was significantly higher in high grade tumors such as poorly differentiated adenocarcinoma than in lower grade tumors such as well or moderately differentiated adenocarcinoma. Higher neuroserpin expression was associated with shorter recurrence-free survival after radical prostatectomy, shorter recurrence-free survival in HRPC patients and shorter overall survival in HRPC patients. The neuroserpin gene may be associated with the development, progression and aggressiveness of prostate cancer. Our present data suggests that higher neuroserpin expression may predict an unfavorable outcome after radical prostatectomy or hormone therapy.

Changes in chromogranin a serum levels during endocrine therapy in metastatic prostate cancer patients

INTRODUCTION

The concept of neuroendocrine (NE) differentiation in prostate cancer has become more widely recognized as its diagnostic, prognostic, and therapeutic usefulness.

PATIENTS AND METHODS

We enrolled 38 patients with stage D prostate cancer who underwent endocrine therapy by medical or surgical castration and oral antiandrogen. According to PSA response, serum levels of CGA as a marker of NE differentiation were measured at the multiple points of time; (1) pre-treatment, (2) complete response (CR), (3) a nadir level of PSA, (4) PSA failure or hormone independent progression. We compared these serum values in relation to efficacy of endocrine therapy.

RESULTS

There was no correlation between serum PSA and CGA values. Patients consisted of 27 with CR and 11 without CR. Serum CGA increased as intervals of endocrine therapy became longer with positive correlation (p < 0.05). Its velocity was higher in patients with PSA failure than in those without it (6.98 vs. 2.09 ng/ml/month, p = 0.011).

CONCLUSION

During endocrine therapy in metastatic prostate cancer patients, serum CGA values were not related to serum PSA levels, and increased as treatment periods became longer. It is suggested that CGA velocity has potential to predict androgen independent progression after endocrine therapy.

Augmented expression of chromogranin A and serotonin in peri-malignant benign prostate epithelium as compared to adenocarcinoma

There is a growing body of evidence that the occurrence of neuroendocrine (NE) differentiation in prostate carcinoma correlates with poor prognosis, tumor progression, and androgen-independence. In the present study, the expression of common NE markers, i.e., chromogranin A (ChGA), serotonin (5HT), neuron-specific enolase (NSE) and adrenomedullin (AM), was retrospectively examined in formalin-fixed, paraffin-embedded prostate tissue samples obtained from patients with adenocarcinoma and from patients with nodular hyperplasia of the prostatic gland (NHPG) (33 and 28, respectively). The statistical analysis of the results (tested the equality of matched pairs of observations using the Wilcoxon matched-pairs signed ranks test) revealed a more prominent expression of ChGA in benign epithelial cells adjacent to adenocarcinomatic lesions (Peri-PAC) than in the adenocarcinoma (PAC) (p = 0.0049). A similar pattern of expression was detected for 5HT (p = 0.000). When comparing the expression of ChGA and 5HT in tissue samples originating in cancer patients with those obtained from NHPG samples, more ChGA and 5HT were expressed in Peri-PAC than in NHPG (p = 0.0004 and 0.002, respectively). The results obtained raise the possibility that adenocarcinoma cells urge some adjacent benign epithelial cells to differentiate into NE cells, which, in turn, may promote tumor growth and invasion.

[Neuroendocrine differentiation in prostate cancer. An unrecognized and therapy-resistant phenotype]

Neuroendocrine (NE) differentiation frequently occurs in common prostatic malignancies and has attracted increasing attention in contemporary prostate cancer research. This particular phenotype, however, usually escapes pathological and clinical detection in routine practice. The present review focuses on the biological properties of NE tumor cells that make them resistant to androgen deprivation and radiation therapy. NE cells produce a number of hormonal growth factors (e.g., serotonin) that may act through endocrine, paracrine, and autocrine mechanisms. Morphogenetic studies have identified intermediate phenotypes between the three basic cell types of the prostatic epithelium indicating their common origin from stem cells located in the basal cell layer. Virtually all prostatic adenocarcinomas show NE differentiation as defined by the most commonly used endocrine marker chromogranin A. Clinical studies suggest that the extent of NE differentiation increases with tumor progression and the development of androgen insensitivity. NE differentiation exclusively occurs in the G0 phase of the cell cycle in which tumor cells are usually resistant to radiation therapy and cytotoxic drugs. In addition, NE tumor cells also escape programmed cell death. Even under androgen deprivation, only 0.16% of NE tumor cells show apoptotic activity. This indicates that the vast majority of NE tumor cells represent an immortal cell population in prostate cancer. Although NE tumor cells do not proliferate, they produce a number of NE growth factors with mitogenic properties that maintain cell proliferation in adjacent (exocrine) tumor cells through a paracrine mechanism. NE tumor cells consistently lack the androgen receptor and are androgen insensitive in all stages of the disease. They derive through a process of intermediate differentiation from exocrine tumor cells, the most prevalent phenotype in common prostatic adenocarcinoma. Elevated serum levels of chromogranin A in prostate cancer patients correlate with poor prognosis and are scarcely influenced by either androgen deprivation or chemotherapy. Looking for NE differentiation is recommended in the pathological and clinical evaluation of prostate cancer patients for whom radiation and androgen deprivation are therapeutic options.