Pattern of progression and survival in hormonally treated metastatic prostate cancer

The pattern of tumor progression on first-line immune checkpoint inhibitor-based systemic therapy for Chinese advanced hepatocellular carcinoma -CLEAP 004 study

Background

For decades, stratification criteria for first-line clinical studies have been highly uniform. However, there is no principle or consensus for restratification after systemic treatment progression based on immune checkpoint inhibitors (ICIs). The aim of this study was to assess the patterns of disease progression in patients with advanced hepatocellular carcinoma (HCC) who are not eligible for surgical intervention, following the use of immune checkpoint inhibitors.

Methods

This is a retrospective study that involved patients with inoperable China liver stage (CNLC) IIIa and/or IIIb. The patients were treated at eight centers across China between January 2017 and October 2022. All patients received at least two cycles of first-line treatment containing immune checkpoint inhibitors. The patterns of disease progression were assessed using RECIST criteria 1.1. Different progression modes have been identified based on the characteristics of imaging progress. The study's main outcome measures were post-progression survival (PPS) and overall survival (OS). Survival curves were plotted using the Kaplan-Meier method to compare the difference among the four groups. Subgroup analysis was conducted to compare the efficacy of different immunotherapy combinations. Variations in the efficacy of immunotherapy have also been noted across patient groups exhibiting alpha-fetoprotein (AFP) levels equal to or exceeding 400ng/mL, in contrast to those with AFP levels below 400ng/mL.

Results

The study has identified four distinct patterns of progress, namely p-IIb, p-IIIa, p-IIIb, and p-IIIc. Diverse patterns of progress demonstrate notable variations in both PPS and OS. The group p-IIb had the longest PPS of 12.7m (95% 9.3-16.1) and OS 19.6m (95% 15.6-23.5), the remaining groups exhibited p-IIIb at PPS 10.5 months (95%CI: 7.9-13.1) and OS 19.2 months (95%CI 15.1-23.3). Similarly, p-IIIc at PPS 5.7 months (95%CI: 4.2-7.2) and OS 11.0 months (95%CI 9.0-12.9), while p-IIIa at PPS 3.4 months (95%CI: 2.7-4.1) and OS 8.2 months (95%CI 6.8-9.5) were also seen. Additional stratified analysis was conducted and showed there were no differences of immunotherapy alone or in combination in OS (HR= 0.92, 95%CI: 0.59-1.43, P=0.68) and PPS (HR= 0.88, 95%CI: 0.57-1.36, P=0.54); there was no significant difference in PPS (HR=0.79, 95% CI: 0.55-1.12, P=0.15) and OS (HR=0.86, 95% CI: 0.61-1.24, P=0.39) for patients with AFP levels at or over 400ng/mL. However, it was observed that patients with AFP levels above 400ng/mL experienced a shorter median progression of PPS (8.0 months vs. 5.0 months) after undergoing immunotherapy.

Conclusion

In this investigation of advanced hepatocellular carcinoma among Chinese patients treated with immune checkpoint inhibitors, we identified four distinct progression patterns (p-IIb, p-IIIa, p-IIIb and p-IIIc) that showed significant differences in PPS and OS. These findings demonstrate the heterogeneity of disease progression and prognosis after immunotherapy failure. Further validation in large cohorts is necessary to develop prognostic models that integrate distinct progression patterns to guide subsequent treatment decisions. Additionally, post-immunotherapy progression in patients with AFP levels ≥400ng/mL indicates a shortened median PPS. These findings provide valuable insights for future personalized treatment decisions.

PSMA PET for Detection of Recurrence

Prostate cancer (PC) is a significant health concern worldwide, with high incidence and mortality rates. Early and accurate detection and localization of recurrent disease at biochemical recurrence (BCR) is critical for guiding subsequent therapeutic decisions and improving patient outcomes. At BCR, conventional imaging consisting of CT, MRI, and bone scintigraphy are recommended by US and European guidelines, however, these modalities all bear certain limitations in detecting metastatic disease, particularly in low-volume relapse at low prostate-specific antigen (PSA) levels. Molecular imaging with PET/CT or PET/MRI using prostate-specific membrane antigen (PSMA) targeting radiopharmaceuticals has revolutionized imaging of PC. Particularly at BCR PC, PSMA PET has shown better diagnostic performance compared to conventional imaging in detecting local relapse and metastases, even at very low PSA levels. The most recent version of the National Comprehensive Cancer Network (NCCN) guideline has included PSMA-targeted PET/CT or PET/MRI for the localization of BCR PC. There are several different PSMA-targeting radiopharmaceuticals labeled with different radioisotopes, each with slightly different characteristics, but overall similar high sensitivity and specificity for PC. PSMA-targeted PET has the potential to significantly impact patient care by guiding personalized treatment decisions and thus improving outcomes in BCR PC patients.

Oligometastatic Bone Disease in Castration-Sensitive Prostate Cancer Patients Treated With Stereotactic Body Radiotherapy Using 68Ga-PSMA PET/CT: TROD 09-004 Study

PURPOSE

To evaluate the outcomes of metastasis-directed treatment (MDT) using stereotactic body radiotherapy (SBRT) for bone-only oligometastasis (OM) detected with gallium prostate-specific membrane antigen (68Ga-PSMA) PET/CT in castration-sensitive prostate cancer (PC) patients.

METHODS

In this multi-institutional study, clinical data of 74 PC patients with 153 bone lesions who were undergoing MDT were retrospectively evaluated. Twenty-seven patients (36.5%) had synchronous, and 47 (63.5%) had metachronous OM. All patients had PC with 5 metastases or fewer detected by 68Ga-PSMA PET/CT and treated using SBRT with a median dose of 20 Gy. The prognostic factors for PC-specific survival (PCSS) and progression-free survival (PFS) were analyzed.

RESULTS

The median follow-up was 27.3 months. Patients with synchronous OM were older and received higher rates of androgen deprivation therapy after SBRT compared with patients with metachronous OM. The 2-year PCSS and PFS rates were 92.0% and 72.0%, respectively. A prostate-specific antigen (PSA) decline was observed in 56 patients (75.7%), and 48 (64.9%) had a PSA response defined as at least 25% decrease of PSA after MDT. The 2-year local control rate per lesion was 95.4%. In multivariate analysis, single OM and PSA response after MDT were significant predictors for better PCSS and PFS. In-field recurrence was observed in 4 patients (6.5%) with 10 lesions at a median of 13.1 months after MDT completion. No serious late toxicity was observed.

CONCLUSIONS

We demonstrated that SBRT is an efficient and well-tolerated treatment option for PC patients with 5 bone-only oligometastases or fewer detected with 68Ga-PSMA PET/CT.

Prostate cancer with low burden skeletal disease at diagnosis: outcome of concomitant radiotherapy on primary tumor and metastases

OBJECTIVE

To evaluate toxicity and clinical outcome in synchronous bone only oligometastatic (≤2 lesions) prostate cancer patients, simultaneously irradiated to prostate/prostatic bed, lymph nodes and bone metastases.

METHODS

From 2/2009 to 6/2015, 39 bone only prostate cancer patients underwent radiotherapy (RT) at "radical" doses to bone metastases (median 2 Gy equivalent dose, EQD2>40Gy, α/β = 1,5), nodes, and prostate/prostatic bed, within the same RT course, in association with androgen deprivation therapy (ADT).Biochemical relapse-free survival, clinical relapse-free survival, freedom from distant metastases and overall survival were evaluated.

RESULTS

After a median follow-up of 46.5 (1.2-103.6) months, 5 patients died from disease progression, 10 experienced biochemical relapse, 19, still in ADT, presented undetectable prostate-specific antigen (PSA) at the last follow-up. Five patients who discontinued ADT after a median of 34 months (5.8-41) are free from biochemical relapse.The 4 year Kaplan-Meier estimates of biochemical relapse-free survival, clinical relapse-free survival, freedom from distant metastases and overall survival were 53.3%, 65.7%, 73.4% and 82.4% respectively.No Grade > 2 acute events and only two severe late urinary events were recorded, not due to the concomitant treatment of primary and metastatic disease.

CONCLUSION

Our results suggest that "radical" and synchronous irradiation of primitive tumor and metastatic disease may be a valid approach in synchronous bone only prostate cancer patients, showing mild toxicity profile and promising survival results.

ADVANCES IN KNOWLEDGE

To the best of our knowledge, this is the first analysis of clinical outcome in synchronous bone-only metastasis (neither nodal nor visceral) patients at diagnosis, treated with radical RT to all disease, associated to ADT.

Treatment of Oligometastatic Hormone-Sensitive Prostate Cancer: A Comprehensive Review

With advancements in diagnostic techniques, including molecular and clinical imaging, that directly target cancer cells, oligometastatic prostate cancer (PCa) is being diagnosed in patients who were, in the past, considered to have localized disease. With accumulating evidence, there has been a paradigm shift in considering aggressive treatments targeted at both the primary tumor and metastatic lesions in an aim to avoid and delay the need for palliative treatments and, ultimately, to achieve survival benefits. However, many questions still remain unanswered regarding the understanding of oligometastatic PCa, from its definition to optimal treatment strategies for each individual. Limited retrospective studies have suggested that interventions, including local and/or metastasis-directed therapy using surgery and radiation therapy (RT), can improve survival outcomes with minimal risk of adverse effects. Such treatments have been shown to decrease the risks of subsequent palliative interventions and to delay the start of androgen-deprivation therapy. Nevertheless, available data are insufficient to draw a reliable conclusion regarding their effect on quality of life measures and overall survival. This comprehensive review overviews data from contemporary literature that have investigated treatments, including surgery and RT, for patients with oligometastatic PCa, namely pelvic lymph node positive disease and limited distant metastases, and summarizes ongoing trials that are evaluating the feasibility of aggressive multimodal treatments.

The Role of Hypofractionated Radiotherapy in Prostate Cancer

PURPOSE OF REVIEW

It is now accepted that prostate cancer has a low alpha/beta ratio, establishing a strong basis for hypofractionation of prostate radiotherapy. This review focuses on the rationale for hypofractionation and presents the evidence base for establishing moderate hypofractionation for localised disease as the new standard of care. The emerging evidence for extreme hypofractionation in managing localized and oligometastatic prostate cancer is reviewed.

RECENT FINDINGS

The 5-year efficacy and toxicity outcomes from four phase III studies have been published within the last 12 months. These studies randomizing over 6000 patients to conventional fractionation (1.8-2.0 Gy per fraction) or moderate hypofractionation (3.0-3.4 Gy per fraction). They demonstrate hypofractionation to be non-inferior to conventional fractionation. Moderate hypofractionation for localized prostate cancer is safe and effective. There is a growing body of evidence in support of extreme hypofractionation for localized prostate cancer. Extreme hypofractionation may have a role in managing prostate oligometastases, but further studies are needed.

The combination of serum insulin, osteopontin, and hepatocyte growth factor predicts time to castration-resistant progression in androgen dependent metastatic prostate cancer- an exploratory study

BACKGROUND

We hypothesized that pretreatment serum levels of insulin and other serum markers would predict Progression-free survival (PFS), defined as time to castration-resistant progression or death, in metastatic androgen-dependent prostate cancer (mADPC).

METHODS

Serum samples from treatment-naïve men participating in a randomized phase 3 trial of ADT +/- chemotherapy were retrospectively analyzed using multiplex assays for insulin and multiple other soluble factors. Cox proportional hazards regression models were used to identify associations between individual factor levels and PFS.

RESULTS

Sixty six patients were evaluable (median age = 72 years; median prostate surface antigen [PSA] = 31.5 ng/mL; Caucasian = 86 %; Gleason score ≥8 = 77 %). In the univariable analysis, higher insulin (HR = 0.81 [0.67, 0.98] p = 0.03) and C-peptide (HR = 0.62 [0.39, 1.00]; p = 0.05) levels were associated with a longer PFS, while higher Hepatocyte Growth Factor (HGF; HR = 1.63 [1.06, 2.51] p = 0.03) and Osteopontin (OPN; HR = 1.56 [1.13, 2.15]; p = 0.01) levels were associated with a shorter PFS. In multivariable analysis, insulin below 2.1 (ln scale; HR = 2.55 [1.24, 5.23]; p = 0.011) and HGF above 8.9 (ln scale; HR = 2.67 [1.08, 3.70]; p = 0.027) levels were associated with longer PFS, while adjusted by OPN, C-peptide, trial therapy and metastatic volume. Four distinct risk groups were identified by counting the number of risk factors (RF) including low insulin, high HGF, high OPN levels, and low C-peptide levels (0, 1, 2, and 3). Median PFS was 9.8, 2.0, 1.6, and 0.7 years for each, respectively (p < 0.001).

CONCLUSION

Pretreatment serum insulin, HGF, OPN, and C-peptide levels can predict PFS in men with mADPC treated with ADT. Risk groups based on these factors are superior predictors of PFS than each marker alone.

Oligometastatic prostate cancer: Metastases-directed therapy?

Since the introduction of anatomical and functional imaging with multiparametric magnetic resonance imaging and choline or prostate-specific membrane antigen positron emission tomography-computed tomography, we are able to diagnose a previously unknown disease, the oligometastatic prostate cancer after local therapy. Reports on surgical and radiation treatment for low-volume metastatic recurrence have shown promising results, with definitive cure in few but a relevant delay of androgen-deprivation therapy with both treatment methods. Obviously, these results need to be validated with prospective randomised data.

A comprehensive review of contemporary role of local treatment of the primary tumor and/or the metastases in metastatic prostate cancer

To provide an overview of the currently available literature regarding local control of primary tumor and oligometastases in metastatic prostate cancer and salvage lymph node dissection of clinical lymph node relapse after curative treatment of prostate cancer. Evidence Acquisition. A systematic literature search was conducted in 2014 to identify abstracts, original articles, review articles, research articles, and editorials relevant to the local control in metastatic prostate cancer. Evidence Synthesis. Local control of primary tumor in metastatic prostate cancer remains experimental with low level of evidence. The concept is supported by a growing body of genetic and molecular research as well as analogy with other cancers. There is only one retrospective observational population based study showing prolonged survival. To eradicate oligometastases, several options exist with excellent local control rates. Stereotactic body radiotherapy is safe, well tolerated, and efficacious treatment for lymph node and bone lesions. Both biochemical and clinical progression are slowed down with a median time to initiate ADT of 2 years. Salvage lymph node dissection is feasible in patients with clinical lymph node relapse after local curable treatment. Conclusion. Despite encouraging oncologic midterm results, a complete cure remains elusive in metastatic prostate cancer patients. Further advances in imaging are crucial in order to rapidly evolve beyond the proof of concept.

Advances in local and ablative treatment of oligometastasis in prostate cancer

Oligometastasis is a state of limited metastatic disease that may be amenable to aggressive local therapy to achieve long-term survival. This review aims to explore the role of ablative radiotherapy and surgical management of prostate cancer (CaP) patients with oligometastasis. We performed a systematic review of the literature from November 2003 to November 2013 in the PubMed and EMBASE databases using structured search terms. From our literature search, we identified 13 cases of oligometastatic CaP managed by surgery. The longest disease-free survival documented was 12 years following pulmonary metastasectomy. We also found 12 studies using radiotherapy to treat oligometastatic CaP with median follow-up ranging from 6 to 43 months. Local control rates and overall survival at 3 years range from 66 to 90% and from 54 to 92%, respectively. Most patients did not report any significant toxicity. The limited current literature suggests oligometastatic CaP may be amenable to more aggressive local ablative therapy to achieve prolonged local control and delay to androgen deprivation therapy (ADT). There is a larger body of evidence supporting the use of radiotherapy than surgery in this disease state. However, no direct comparison with ADT is available to suggest an improvement in overall survival. Further studies are required to determine the role of aggressive-targeted local therapy in oligometastatic CaP.

Prognostic factors influencing prostate cancer-specific survival in non-castrate patients with metastatic prostate cancer

BACKGROUND

In non-castrate prostate cancer (PCa), the prognostic value of the number of metastases on prostate cancer-specific survival (PCSS) is not well studied.

METHODS

We retrospectively analyzed the medical records of 1,206 patients, referred for radiotherapy of the prostate (bed) following diagnosis of PCa. Distant metastases (nodal, skeletal, and/or visceral) developed in 121 patients following curative treatment, of which 80 with complete records were not castrated at time of metastasis. The treatment at time of metastases was androgen deprivation therapy (ADT; n = 22), active surveillance (n = 10) or metastasis-directed therapy (MDT; n = 48). Cox-regression analyses were used to examine the influence of different variables on PCSS.

RESULTS

The median follow-up from primary PCa treatment was 6.9 years with a median interval from diagnosis to first metastatic event of 4.1 year (range: 0.2-15 years). The primary site of metastases was limited to lymph nodes (48%), bone (39%), and viscera (1%) or a combination (12%). Median PCSS from diagnosis of noncastrate metastases was 6.6 years (95% confidence interval [CI], 5.6-7.7 years). A longer premetastatic PSA doubling time (DT) (hazard ratio [HR] 0.73; 95% CI: 0.57-0.92), a lower number of metastases at first presentation (HR 1.07; 95% CI: 1.02-1.12) and pattern of metastatic spread (HR 3.6; 95% CI: 1.13-11.8 for extensive vs. minimal) were associated with improved PCSS.

CONCLUSION

A longer PSA DT, involvement of nodes or axial skeleton and a lower number of metastases are associated with an improved PCSS in non-castrated patients developing metastases.

Salvage stereotactic body radiotherapy for patients with limited prostate cancer metastases: deferring androgen deprivation therapy

BACKGROUND

We investigated whether repeated stereotactic body radiotherapy (SBRT) of oligometastatic disease is able to defer the initiation of palliative androgen deprivation therapy (ADT) in patients with low-volume bone and lymph node metastases.

PATIENTS AND METHODS

Patients with up to 3 synchronous metastases (bone and/or lymph nodes) diagnosed on positron emission tomography, following biochemical recurrence after local curative treatment, were treated with (repeated) SBRT to a dose of 50 Gy in 10 fractions. Androgen deprivation therapy-free survival (ADT-FS) defined as the time interval between the first day of SBRT and the initiation of ADT was the primary end point. ADT was initiated if more than 3 metastases were detected during follow-up even when patients were still asymptomatic or in case of a prostate specific antigen elevation above 50 ng/mL in the absence of metastases. Secondary end points were local control, clinical progression-free survival, and toxicity. Toxicity was scored using the Common Terminology Criteria for Adverse Events.

RESULTS

We treated 24 patients with a median follow-up of 24 months. Ten patients started with ADT resulting in a median ADT-FS of 38 months. The 2-year local control and clinical progression-free survival was 100% and 42%, respectively. Eleven and 3 patients, respectively, required a second and third salvage treatment for metachronous low-volume metastatic disease. No grade 3 toxicity was observed.

CONCLUSION

Repeated salvage SBRT is feasible, well tolerated and defers palliative ADT with a median of 38 months in patients with limited bone or lymph node PCa metastases.

Methods for evaluation of structural and biological properties of antiinvasive natural products

Prostate cancer is considered the most common cancer form among males in Western countries. Very limited options are available for the treatment of advanced metastatic prostate cancer. More than 50% of today's anticancer drugs are natural products or derived from a natural origin. To discover new entities with potential to treat prostate cancer at androgen-refractory stages, 36 structurally diverse natural products were screened using functional-based assays. The tested compounds were selected broadly from major secondary metabolites of plants, marine invertebrates, and fungi. These diverse entities were prescreened for their antiinvasive ability against prostate cancer cells, PC-3M, using spheroid disaggregation assay. Active representatives including three selected structural classes, a macrolide, a β-carboline alkaloid, and a phenylmethylene hydantoin (PMH), were then tested for their ability to stabilize junctional complexes and enhance cell-cell adhesion of androgen independent prostate cancer cells. Transepithelial resistance (TER) and paracellular permeability assays were used to elicit the aforementioned properties. These studies led to the emergence of PMHs as a small molecule class from the marine sponge Hemimycale arabica with a unique potential to attenuate CT-stimulated prostate cancer growth, metastasis, paracellular permeability, and enhance TER and cell-cell adhesion of prostate cancer cells. The unique activities of PMHs were validated using several in vitro assays followed by in vivo testing in two mice models. A 3D QSAR was established using SYBYL 8.1-Comparative Molecular Field Analysis (CoMFA) model. This chapter includes the methodology for evaluation of structural and biological properties of new antiinvasive molecules with an exceptional potential to stabilize junctional complexes from diverse natural product sources.

The independent value of tumour volume in a contemporary cohort of men treated with radical prostatectomy for clinically localized disease

OBJECTIVE

To determine if prostate tumour volume is an independent prognostic factor in a contemporary cohort of men who had a radical prostatectomy (RP) for clinically localized disease, as the effect of tumour volume on prostate cancer outcomes has not been consistently shown in the era of widespread screening with prostate-specific antigen (PSA).

PATIENTS AND METHODS

The study included 856 men who had RP from 1998 to 2007 for localized prostate cancer. Tumour volume based on pathology was analysed as a continuous and categorized (<0.26, 0.26-0.50, 0.51-1.00, 1.01-2.00, 2.01-4.00, >4.00 mL) variable using Cox proportional hazards regression and Kaplan-Meier analysis. A multivariable analysis was also conducted controlling for PSA level, Gleason grade, surgical margins, and pathological stage.

RESULTS

Tumour volume had a positive association with grade and stage, but did not correlate with biochemical recurrence-free survival on univariate analysis as a continuous variable (hazard ratio 1.00, P = 0.09), and was only statistically significant for volumes of >4 mL as a categorical variable. No tumour volume was an independent predictor of prostate cancer recurrence on multivariate analysis. There was no difference between tumour volume and time to cancer recurrence for organ-confined tumours using Kaplan-Meier analysis. In low-risk patients (PSA level <10 ng/mL, Gleason score < or = 6, clinical stage T1c/T2a) tumour volume did not correlate with biochemical recurrence-free survival in univariate or multivariable analysis.

CONCLUSIONS

There is no evidence that tumour volume is an independent predictor of prostate cancer outcome and it should not be considered as a marker of tumour risk, behaviour or prognosis.

Overexpression of chromatin assembly factor-1 (CAF-1) p60 is predictive of adverse behaviour of prostatic cancer

AIMS

Prostatic cancer may remain organ-confined indefinitely; in a number of patients, however it gives rise to clinical symptoms and death. The biological behaviour of this tumour mostly remains difficult to predict. A promising tool for diagnosis and prognosis of some human tumours is the chromatin assembly factor-1 (CAF-1), involved in the control of higher order chromatin organization. The aim was to explore the role of CAF-1/p60 protein as a new prognostic marker for prostatic cancer.

METHODS AND RESULTS

The expression of CAF-1/p60 was evaluated by immunohistochemistry and Western blotting in a selected series of prostatic cancers and in prostatic cancer cell lines. Results were compared with clinicopathological data and outcome of patients. CAF-1/p60 was expressed in all cases, with a linear increase from low-grade tumours (Gleason score <7) to high-grade prostatic cancers (Gleason score >7). By comparing results with follow-up data, a significant association between overexpression of CAF-1/p60 and unfavourable behaviour of prostatic cancer emerged, and its predictive value was independent of classical prognostic factors.

CONCLUSIONS

In our series of cases, overexpression of CAF-1/p60 characterized prostatic cancers with a worse prognosis. CAF-1/p60 has a potential role as a new reliable prognostic biomarker for prostatic cancer.

Identification of a small molecule class to enhance cell-cell adhesion and attenuate prostate tumor growth and metastasis

Expression of calcitonin (CT) and its receptor (CTR) is elevated in advanced prostate cancer, and activated CT-CTR autocrine axis plays a pivotal role in tumorigenicity and metastatic potential of multiple prostate cancer cell lines. Recent studies suggest that CT promotes prostate cancer metastasis by reducing cell-cell adhesion through the disassembly of tight and adherens junctions and activation of beta-catenin signaling. We attempted to identify a class of molecules that enhances cell-cell adhesion of prostate cells and reverses the disruptive actions of CT on tight and adherens junctions. Screening several compounds led to the emergence of phenyl-methylene hydantoin (PMH) as a lead candidate that can augment cell-cell adhesion and abolish disruptive actions of CT on junctional complexes. PMH reduced invasiveness of PC-3M cells and abolished proinvasive actions of CT. Importantly, PMH did not display significant cytotoxicity on PC-3M cells at the tested doses. I.p. administered PMH and its S-ethyl derivative remarkably decreased orthotopic tumor growth and inhibited the formation of tumor micrometastases in distant organs of nude mice. PMH treatment also reduced the growth of spontaneous tumors in LPB-Tag mice to a significant extent without any obvious cytotoxic effects. By virtue of its ability to stabilize cell junctions, PMH could reverse the effect of CT on junctional disruption and metastasis, which strengthens the possibility of using PMH as a potential drug candidate for CT-positive androgen-independent prostate cancers.

Cadherin switching and activation of beta-catenin signaling underlie proinvasive actions of calcitonin-calcitonin receptor axis in prostate cancer

Calcitonin, a neuroendocrine peptide, and its receptor are localized in the basal epithelium of benign prostate but in the secretory epithelium of malignant prostates. The abundance of calcitonin and calcitonin receptor mRNA displays positive correlation with the Gleason grade of primary prostate cancers. Moreover, calcitonin increases tumorigenicity and invasiveness of multiple prostate cancer cell lines by cyclic AMP-dependent protein kinase-mediated actions. These actions include increased secretion of matrix metalloproteinases and urokinase-type plasminogen activator and an increase in prostate cancer cell invasion. Activation of calcitonin-calcitonin receptor autocrine loop in prostate cancer cell lines led to the loss of cell-cell adhesion, destabilization of tight and adherens junctions, and internalization of key integral membrane proteins. In addition, the activation of calcitonin-calcitonin receptor axis induced epithelial-mesenchymal transition of prostate cancer cells as characterized by cadherin switch and the expression of the mesenchymal marker, vimentin. The activated calcitonin receptor phosphorylated glycogen synthase kinase-3, a key regulator of cytosolic beta-catenin degradation within the WNT signaling pathway. This resulted in the accumulation of intracellular beta-catenin, its translocation in the nucleus, and transactivation of beta-catenin-responsive genes. These results for the first time identify actions of calcitonin-calcitonin receptor axis on prostate cancer cells that lead to the destabilization of cell-cell junctions, epithelial-to-mesenchymal transition, and activation of WNT/beta-catenin signaling. The results also suggest that cyclic AMP-dependent protein kinase plays a key role in calcitonin receptor-induced destabilization of cell-cell junctions and activation of WNT-beta-catenin signaling.

Calcitonin receptor-stimulated migration of prostate cancer cells is mediated by urokinase receptor-integrin signaling

Abundance of calcitonin (CT) and calcitonin receptor (CTR) mRNA in primary prostate tumors positively correlates with tumor grade, and exogenously added CT increases the invasion of prostate cancer cell lines. We examined acute and chronic actions of CT on migration of highly metastatic PC-3M cells and poorly invasive LNCaP cells on several extracellular matrices in a spheroid disaggregation/migration assay. While PC-3M spheroids displayed maximum disaggregation/migration on vitronectin (VN), LNCaP spheroids preferred collagen but also migrated significantly on VN. Up-regulation of CT significantly enhanced disaggregation/migration of PC-3M spheroids on VN, but not on fibronectin. In contrast, down-regulation of CT, CTR, protein kinase A or urokinase-type plasminogen activator receptor (uPAR) led to amelioration of PC-3M spheroid disaggregation/migration. CT selectively increased surface activity of alpha v beta 3 or alpha 6 beta 5 integrins in PC-3M and LNCaP cell lines, respectively, and uPAR-integrin association. Finally, either CT or urokinase could completely restore migration of CT-knock-down PC-3M spheroids. But, only forced expression of urokinase receptor coupled with exogenous addition of urokinase restored migration of CTR-knock-down spheroids. These results support our hypothesis that up-regulation of CT biosynthesis and activation of CT-CTR axis in primary prostate tumors may have direct relevance in their progression to the metastatic phenotype.

Routine interval computed tomography to detect new soft-tissue disease might be unnecessary in patients with androgen-independent prostate cancer and metastasis only to bone

OBJECTIVE

To identify patients with androgen-independent prostate cancer (AIPC) with bone metastasis and no soft-tissue metastases at the time of protocol enrollment, and analyse their disease progression by computed tomography (CT), bone scan, and prostate-specific antigen (PSA) level to determine the utility of routine interval CT in such patients.

PATIENTS AND METHODS

Bone is the most common metastatic site in patients with AIPC and the only site of metastatic disease for many; because some with initial bone metastasis eventually develop soft-tissue disease, many clinical trials use routine CT to monitor for the latter as a sign of disease progression, but the actual incidence of new soft-tissue metastases is unknown and the role of routine interval CT in monitoring for disease progression, especially for asymptomatic patients, is unclear. Thus we reviewed 175 cases of metastatic AIPC from three randomized phase II clinical trials (docetaxel/thalidomide, docetaxel/vaccine, and ketoconazole/alendronate) at the National Cancer Institute between 1995 and 2004. The patients' PSA levels were assessed every 4 weeks, and CT and bone scans were done every 2-3 months. We retrospectively identified patients with bone metastasis only and examined subsequent CT for the occurrence of soft-tissue disease. For patients with progressive disease, we also examined bone scan and PSA progression.

RESULTS

Of 175 patients with metastatic prostate cancer, 105 (60%) had bone metastasis only, 12 (6.9%) had soft-tissue metastases only, and 58 (33.1%) had both bone and soft-tissue metastases. The median (range) follow-up was 8 (1-44) months for the 105 patients with bone metastasis only. During that time, two patients (1.9%) developed new soft-tissue disease; one developed right iliac fossa lymphadenopathy after 8 months and the other developed a perirectal mass after 12 months. The patient with new lymphadenopathy also had multiple new bone lesions identified by bone scan and PSA progression. The patient with the perirectal mass had PSA progression and a palpable abnormality.

CONCLUSION

This review of patients with AIPC and bone metastasis only, followed for a median of 8 months on clinical trials, shows that the incidence of asymptomatic new soft-tissue disease as the only sign of disease progression is quite low. Therefore, routine CT to exclude new soft-tissue disease in this population appears to be unwarranted. We recommend that for these patients CT is done only at the time of disease progression, as shown by bone scan, PSA level, or clinical presentation. We do not exclude the possibility that patients who remain on trial for significantly longer periods might benefit from routine interval CT.

Calcitonin Increases Tumorigenicity of Prostate Cancer Cells: Evidence for the Role of Protein Kinase A and Urokinase-Type Plasminogen Receptor

The expression of human (h) calcitonin (CT) and its receptor (CTR) is localized to basal epithelium in benign prostates but is distributed in whole epithelium of malignant prostates. Moreover, the abundance of hCT and CTR mRNA in primary prostate tumors positively correlates with the tumor grade. We tested the hypothesis that the modulation of endogenous hCT expression of prostate cancer (PC) cell lines alters their oncogenicity. The effect of modulation of hCT expression on oncogenic characteristics was examined in LNCaP and PC-3M cell lines. The endogenous hCT expression was modulated using either constitutively active expression vector containing hCT cDNA or anti-hCT hammerhead ribozymes. The changes in the oncogenicity of cell sublines was assessed with cell proliferation assays, invasion assays, colony formation assays, and in vivo growth in athymic nude mice. Up-regulation of hCT in PC-3M cells and or enforced hCT expression in LNCaP cells dramatically enhanced their oncogenic characteristics. In contrast, the down-regulation of hCT in PC-3M cells led to a dramatic decline in their oncogenicity. These results, when combined with our other results, that the expression of hCT in primary PCs increase with tumor grade, suggest an important role for hCT in the progression of PC to a metastatic phenotype.

Calcitonin stimulates the secretion of urokinase-type plasminogen activator from prostate cancer cells: its possible implications on tumor cell invasion

Calcitonin (CT) is synthesized and secreted in prostate epithelium, and its secretion from malignant prostates is several folds higher than that in benign prostates. CT receptor (CTR) is expressed in malignant prostate epithelium, and its activation increases invasiveness of prostate cancer (PC) cells via activation of protein kinase A. Since the role of urokinase-type plasminogen activator (uPA) in invasion of PC has been established, we tested the hypothesis that CT increases invasion of PC cells by stimulating uPA secretion from PC cells. Exogenously added CT stimulated the secretion of uPA from PC-3M cells in a dose-dependent manner, which was blocked by Rp.cAMP, a competitive inhibitor of protein kinase A. CT stimulated the secretion of MMP-2 and MMP-9 from PC-3M cells, and also increased their invasiveness. Both these actions of CT were blocked by uPA-neutralizing antibodies. Immunofluorescence studies with PC-3M cells suggest that CT stimulated redistribution of cellular uPA to focal adhesion sites, which was further confirmed by co-immunoprecipitation of uPA with focal adhesion kinase (FAK) in response to CT. These results suggest that CT increases invasiveness of PC cells by stimulating PKA-mediated uPA secretion and by redirecting the secreted uPA to focal adhesion sites. The results also suggest that uPA may, at least in part, mediate proinvasive actions of CT on PC cells by stimulating the secretion of gelatinases and degradation of focal adhesion sites.

Calcitonin increases invasiveness of prostate cancer cells: Role for cyclic AMP-dependent protein kinase A in calcitonin action

Calcitonin (CT) is synthesized and secreted in prostate epithelium, and its secretion from malignant prostates is several-fold higher than from benign prostates. CT receptor (CTR) is expressed in malignant prostate epithelium, and its activation stimulates growth of prostate cancer (PC) cells via activation of adenylyl cyclase and calcium/phospholipid pathways. To identify the role of "CT System" in prostate cancer, we tested the expression of CT and CTR mRNAs in invading tumor cells of prostate cancer specimens. The effect of CT on in vitro invasion of PC cell lines and on activation of gelatinases was also examined. The cells of primary tumors and those invading stroma co-expressed CT/CTR mRNAs. Exogenously added CT increased in vitro invasion of PC cell lines and caused a rapid, several-fold but transient increase in protein kinase A activity. In contrast, anti-CT serum caused a dose-dependent inhibition of in vitro invasion of PC-3M cells. CT also increased the concentration and activities of MMP-2 and MMP-9. Rp.cAMP, a competitive inhibitor of cAMP-dependent protein kinase A, myristoylated protein kinase A inhibitory peptide (PKI) as well as the expression of dominant negative form of PKA all attenuated basal in vitro invasion of PC-3M cells, and CT could not increase in vitro invasiveness in their presence. These results suggest that overexpression of "CT System" in invasive PC tumors significantly contributes to increased invasiveness of prostate cancer cells. The action of CT may be mediated by protein kinase A signaling, which subsequently leads to increased cell invasion and secretion of gelatinases.

Prognostic significance of changes in prostate-specific antigen in patients with metastasis prostate cancer after endocrine treatment

Patients with metastatic prostate cancer respond to androgen withdrawal therapy, but progression to androgen independence is frequently observed. To clarify the predictor of response to endocrine therapy, the role of PSA changes and the prognosis of the patients were evaluated in 115 Japanese cases of prostate cancer with distant metastases treated with androgen withdrawal therapy. When patients were divided according to the pretreatment PSA value (high, > or = 500, median; 500 > PSA > or = 100, low; 100 >), patients whose initial PSA levels were high had a worse cause-specific survival. PSA value at 3 or 6 months following endocrine treatment, PSA nadir, and percent decrease of PSA were associated with prolonged survival. Clinical relapse was observed in 68 patients. Patients with distant recurrence had shorter time to PSA elevation than those with local recurrence. In metastatic prostate cancer patients treated with androgen withdrawal, serial measurement of PSA could distinguish nonfavorable responders early in the course of treatment and assist in monitoring for disease progression.

Immediate vs. delayed androgen deprivation for prostate cancer

Androgen ablation has been the standard treatment of symptomatic patients with metastatic prostate cancer for more than 50 years. Within the last 15 years, the introduction of prostate-specific antigen (PSA) has induced a stage migration toward less extensive disease and a dramatic decrease in the proportion of men presenting with N+/M+ disease. Historical studies, conducted during the pre-PSA era, are therefore of limited interest in counseling modern patients. The routine use of radical therapies such as radical prostatectomy and radiotherapy has considerably expanded the problem of timing of endocrine treatment in range and complexity. Advanced disease is now diagnosed in patients with limited involvement of extraprostatic sites and even in patients presenting an isolated elevation of PSA after radical treatment. In the absence of clear guidelines, data from past literature and ongoing modern studies were compiled in the present review in an attempt to generate practical considerations.