Chemotherapy and radiation for prostate cancer

A young patient with prostatic carcinoma with testicular metastasis

Prostate cancer is one of the most frequent cancers in males and commonly a disease of the older population, but it is increasingly seen among older adolescents and young adults. The common sites of metastasis of prostatic carcinoma are bones and regional lymph nodes. Testicular metastasis from prostatic carcinoma is an infrequent presentation. We report a case of a young patient with prostatic carcinoma and multiple metastases, including bilateral testis. A 40-year-old male presented with lower urinary tract voiding symptoms and back pain for three months. His prostate-specific antigen level was elevated at 13.98 ng/ml. A magnetic resonance imaging of the prostate revealed two PIRADS V lesions and metastases in multiple bones and regional lymph nodes. On follow up, the patient complained of bilateral testicular swelling and ultrasound scan of the testes revealed bilateral testicular metastasis. Fine needle aspiration cytology of right-side testicular lesion revealed malignant cells compatible with metastasis from prostate cancer. Later involvement of multilevel vertebral and skull metastases was identified by magnetic resonance imaging. A T_3bN₁M1_c staging of prostate cancer was made, androgen deprivation therapy followed by chemo and radiotherapy was instituted, following extensive discussion with the patient. Unfortunately the patient succumbed to the illness during the course of treatment. This case report is of a patient with rare presentation of bilateral testicular metastasis with prostate cancer in young age.

Mesenchymal stem cells and prostate cancer: A concise review of therapeutic potentials and biological aspects

Prostate cancer (PCa) arises from a cancer stem or progenitor cell with homogenous characteristics, especially among the aging men population. Over the past decade, the increasing PCa incidence has led to significant changes in both disease diagnosis and treatment. Recently, the therapeutic aspects of stem cells in many cancers, including PCa, have been debatable. The new generation of PCa studies seek to present definitive treatments with reduced therapeutic side effects. Since discovering unique properties of stem cells in modulating immunity, selective migration to inflammatory regions, and secretion of various growth factors, they have been a promising therapeutic target. The existing properties of stem cell therapy bring new opportunities for cancer inhibition: transferring chemotherapeutics, activating prodrugs, affecting the expression of genes involved in cancer, genetically modifying the production of anti-cancer compounds, proteins, and/or deriving extracellular vesicles (EVs) containing therapeutic agents from stem cells. However, their dual properties in carcinogenicity as well as their ability to inhibit cancer result in particular limitations studying them after administration. A clear understanding of the interaction between MSCs and the prostate cancer microenvironment will provide crucial information in revealing the precise applications and new practical protocols for clinical use of these cells..

Role of prostate cancer stem-like cells in the development of antiandrogen resistance

Androgen deprivation therapy (ADT) is the standard of care treatment for advance stage prostate cancer. Treatment with ADT develops resistance in multiple ways leading to the development of castration-resistant prostate cancer (CRPC). Present research establishes that prostate cancer stem-like cells (CSCs) play a central role in the development of treatment resistance followed by disease progression. Prostate CSCs are capable of self-renewal, differentiation, and regenerating tumor heterogeneity. The stemness properties in prostate CSCs arise due to various factors such as androgen receptor mutation and variants, epigenetic and genetic modifications leading to alteration in the tumor microenvironment, changes in ATP-binding cassette (ABC) transporters, and adaptations in molecular signaling pathways. ADT reprograms prostate tumor cellular machinery leading to the expression of various stem cell markers such as Aldehyde Dehydrogenase 1 Family Member A1 (ALDH1A1), Prominin 1 (PROM1/CD133), Indian blood group (CD44), SRY-Box Transcription Factor 2 (Sox2), POU Class 5 Homeobox 1(POU5F1/Oct4), Nanog and ABC transporters. These markers indicate enhanced self-renewal and stemness stimulating CRPC evolution, metastatic colonization, and resistance to antiandrogens. In this review, we discuss the role of ADT in prostate CSCs differentiation and acquisition of CRPC, their isolation, identification and characterization, as well as the factors and pathways contributing to CSCs expansion and therapeutic opportunities.

Targeted Chemoradiotherapy of Prostate Cancer Using Gold Nanoclusters with Protease Activatable Monomethyl Auristatin E

Combined radiotherapy (RT) and chemotherapy are prescribed to patients with advanced prostate cancer (PCa) to increase their survival; however, radiation-related side effects and systematic toxicity caused by chemotherapeutic drugs are unavoidable. To improve the precision and efficacy of concurrent RT and chemotherapy, we have developed a PCa-targeted gold nanocluster radiosensitizer conjugated with a highly potent cytotoxin, monomethyl auristatin E, PSMA-AuNC-MMAE, for RT and chemotherapy of PCa. This approach resulted in enhanced uptake of NCs by PSMA-positive cancer cells, targeted chemotherapy, and increased efficacy of RT both in vitro and in vivo. In addition, the combination of gold and MMAE further increased the efficacy of either of the agents delivered alone or simultaneously but not covalently linked. The PSMA-AuNC-MMAE conjugates improve the specificity and efficacy of radiation and chemotherapy, potentially reducing the toxicity of each therapy and making this an attractive avenue for clinical treatment of advanced PCa.

The Therapeutic Potential of FLASH-RT for Pancreatic Cancer

Simple Summary

Ultra-high dose rate radiation, widely nicknamed FLASH-RT, kills tumors without significantly damaging nearby normal tissues. This selective sparing of normal tissue by FLASH-RT tissue is called the FLASH effect. This review explores some of the proposed mechanisms of the FLASH effect and the current data that might support its use in pancreatic cancer. Since radiation for pancreatic cancer treatment is limited by GI toxicity issues and is a disease with one of the lowest five-year survival rates, FLASH-RT could have a large impact in the treatment of this disease with further study.

Abstract

Recent preclinical evidence has shown that ionizing radiation given at an ultra-high dose rate (UHDR), also known as FLASH radiation therapy (FLASH-RT), can selectively reduce radiation injury to normal tissue while remaining isoeffective to conventional radiation therapy (CONV-RT) with respect to tumor killing. Unresectable pancreatic cancer is challenging to control without ablative doses of radiation, but this is difficult to achieve without significant gastrointestinal toxicity. In this review article, we explore the propsed mechanisms of FLASH-RT and its tissue-sparing effect, as well as its relevance and suitability for the treatment of pancreatic cancer. We also briefly discuss the challenges with regard to dosimetry, dose rate, and fractionation for using FLASH-RT to treat this disease.

The role of regulatory T cells in the pathogenesis and treatment of prostate cancer

Despite developments in the treatment of various cancers, prostate cancer is one of the deadliest diseases known to men. Systemic therapies such as androgen deprivation, chemotherapy, and radiation therapy have not been very successful in treating this disease. Numerous studies have shown that there is a direct relationship between cancer progression and inhibition of anti-tumor immune responses that can lead to progression of various malignancies, including prostate cancer. Interestingly, CD4⁺CD25⁺FoxP3⁺ regulatory T cells significantly accumulate and increase in draining lymph nodes and PBMCs of patients with prostate cancer and other solid tumors. In vivo and in vitro studies have shown that Tregs can suppress anti-tumor responses, which is directly related to the increased risk of cancer recurrence. Tregs are essential for preserving self-tolerance and inhibiting extra immune responses harmful to the host. Since the tumor-related antigens are mainly self-antigens, Tregs could play a major role in tumor progression. Accordingly, it has discovered that prostate cancer patients with higher Tregs have poor prognosis and low survival rates. However, anti-tumor responses can be reinforced by suppression of Tregs with using monoclonal antibodies against CD25 and CTLA-4. Therefore, depleting Tregs or suppressing their functions could be one of the effective ways for prostate cancer immunotherapy. The purpose of this review is to investigate the role of Treg cells in the progression of prostate cancer and to evaluate effective strategies for the treatment of prostate cancer by regulating Treg cells.

Targeted Radiosensitizers for MR-Guided Radiation Therapy of Prostate Cancer

Adjuvant radiotherapy is frequently prescribed to treat cancer. To minimize radiation-related damage to healthy tissue, it requires high precision in tumor localization and radiation dose delivery. This can be achieved by MR guidance and targeted amplification of radiation dose selectively to tumors by using radiosensitizers. Here, we demonstrate prostate cancer-targeted gold nanoparticles (AuNPs) for MR-guided radiotherapy to improve the targeting precision and efficacy. By conjugating Gd(III) complexes and prostate-specific membrane antigen (PSMA) targeting ligands to AuNP surfaces, we found enhanced uptake of AuNPs by PSMA-expressing cancer cells with excellent MR contrast and radiation therapy outcome in vitro and in vivo. The AuNPs binding affinity and r₁ relaxivity were dramatically improved and the combination of Au and Gd(III)provided better tumor suppression after radiation. The precise tumor localization by MR and selective tumor targeting of the PSMA-1-targeted AuNPs could enable precise radiotherapy, reduction in irradiating dose, and minimization of healthy tissue damage.

Impact and Outcomes of Pretreatment Total Serum Testosterone on Localized Prostate Cancer Patients

Purpose

To investigate how pretreatment testosterone levels correlate with progression-free survival, metastasis-free survival, and overall survival in a propensity-adjusted localized prostate cancer population.

Methods

Men diagnosed with clinical NCCN-risk stratified very-low, low, intermediate, high, and/or very-high risk prostate cancer who had a baseline total serum testosterone level≥100 ng/dl measured within the 100 days preceding the first definitive therapy were identified from our prospectively gathered institutional database. Cohorts below (100-239 ng/dl), within (240-593 ng/dl), or above (594 + ng/dl) one standard deviation from the mean testosterone level (416 ng/dl) were used for comparison. Progression-free, metastasis-free, and overall survival were evaluated. A separate cohort of men not receiving ADT was used to evaluate testosterone recovery after various treatment modalities (surgery, external beam radiation, brachytherapy, or combined EBRT + Brachy).

Results

There was no statistically significant difference between the low, average, and high testosterone cohorts for PFS, MFS, or OS. In men not using ADT, there were no statistically significant changes in testosterone levels 1 year after therapy, regardless of therapy type.

Conclusion

In men with serum testosterone levels >=100 ng/dl at diagnosis, baseline testosterone does not impact PFS, MFS, or OS. Recovery of testosterone back to baseline is expected for men undergoing either surgery, external beam or brachytherapy, or combined modality radiation when not using ADT.

Contribution of Pyk2 pathway and reactive oxygen species (ROS) to the anti-cancer effects of eicosapentaenoic acid (EPA) in PC3 prostate cancer cells

Background

n-3 polyunsaturated fatty acids (n-3 PUFAs), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), are thought to exert protective effects in cardiovascular diseases. In addition, n-3 PUFAs have demonstrated anti-cancer effects in vitro and in vivo.

Objective

We investigated the anti-cancer effects and mechanism of action of EPA on PC3 prostate cancer cells in vitro.

Methods

PC3 cells were treated with various concentrations of EPA, and cell survival and the abilities of migration and invasion were evaluated. The time course of the growth inhibitory effect of EPA on PC3 cells was also assessed. The mechanism underlying the anti-cancer effects of EPA was investigated by human phosphokinase and human apoptosis antibody arrays, and confirmed by western blot analysis. We also examined the contribution of reactive oxygen species (ROS) to the effects of EPA using the ROS inhibitor N-acetyl cysteine.

Results

EPA decreased the survival of PC3 cells in a dose-dependent manner within 3 h of application, with an effective concentration of 500 μmol/L. EPA inhibited proline-rich tyrosine kinase (Pyk)2 and extracellular signal-regulated kinase 1/2 phosphorylation as determined by western blotting and the antibody arrays. The growth of PC3 cells was inhibited by EPA, which was dependent on ROS induction, while EPA inhibited Pyk2 phosphorylation independent of ROS production.

Conclusions

Inhibition of Pyk2 phosphorylation and ROS production contribute to the anticancer effects of EPA on PC3 cells.

Sites of synchronous distant metastases and prognosis in prostate cancer patients with bone metastases at initial diagnosis: a population-based study of 16,643 patients

BACKGROUND

Bone is a preferential site for prostate cancer (PCa) metastasis. However, sites of synchronous distant metastases in PCa patients with bone metastases at initial diagnosis and their impacts on prognosis are still unclear, limiting our ability to better stratify and treat the patients. In this study, we examined the sites of synchronous extra-skeletal metastases in de novo PCa patients with bone metastases and their associated prognoses.

METHODS

In total, 16,643 de novo PCa patients with bone metastases from the SEER database were included. After stratification of metastatic sites (bone, lung, liver, and brain) and treatment modalities, overall survival (OS) and independent predictors of OS, were analyzed.

RESULTS

Lung was the most frequent site of synchronous metastases, followed by liver, while brain metastases were relatively uncommon. Patients with bone-only metastases showed the longest mean survival time (35.87 months, p < 0.001), followed by patients with bone and lung metastases (30.74 months, p < 0.001). Patients with bone and liver metastases had the shortest mean survival time (17.39 months, p < 0.001). Age > 70 years, unmarried status, high tumor grade, prostate-specific antigen (PSA) > 50 ng/ml, and Gleason score ≥ 8 were associated with poor OS (all p < 0.01). Asian or Pacific Islander ethnic background was associated with a favorable OS (all p < 0.01). Chemotherapy improved OS in patients without brain metastases (all p < 0.05). For patients with bone-only metastases, radical prostatectomy (RP) (HR, 0.339; 95% CI 0.231-0.495; p < 0.001), brachytherapy (BT) (HR, 0.567; 95% CI 0.388-0.829; p = 0.003), and chemotherapy (HR, 0.850; 95% CI 0.781-0.924; p < 0.001) were associated with prolonged OS.

CONCLUSIONS

Age, race, tumor grade, PSA, Gleason score, sites of synchronous extra-skeletal metastases, as well as treatment modalities affected OS in newly diagnosed PCa patients with bone metastases. Synchronous liver metastases were associated with poor OS. Chemotherapy improved OS in patients without brain metastases. RP and BT improved OS in patients with bone-only metastases. Further investigation is warranted to validate these findings.