Hormone-refractory Prostate Cancer Research Articles

Aryl Hydrocarbon Receptor Signaling in Prostate Cancer Therapy: A Review of Implications for Anti-androgen Treatment Strategies and Resistance.

Prostate cancer is a leading cause of cancer-related morbidity and mortality in men, frequently exhibiting resistance to conventional anti-androgen therapies. This review investigates the emerging significance of the aryl hydrocarbon receptor (AhR) in prostate cancer, focusing on its role in modulating androgen receptor (AR) signaling and its potential as a therapeutic target. AhR, traditionally known for detoxifying harmful compounds, has been increasingly recognized for its dual capacity to either enhance or inhibit AR activity based on cellular context and specific coactivators. Furthermore, AhR influences tumor progression independently of AR by regulating genes involved in cell cycle control and apoptosis. This narrative review synthesizes current research on AhR's multifaceted roles in prostate cancer, evaluates its potential as a biomarker, and discusses the therapeutic implications of targeting AhR, particularly for hormone-refractory prostate cancer. Our findings underscore the necessity for personalized AhR-targeted therapies and advocate for continued clinical research to fully leverage AhR's therapeutic potential.

Docetaxel in hormone-sensitive advanced prostate cancer; GENESIS-SEFH evaluation reporta

Prostate cancer (PC) is the most common urogenital malignancy in older men and the second leading cause of death by cancer in men in Europe. Current therapeutic practice considers Androgen Deprivation Therapy (ADT) as first line treatment for clinically localized prostate cancer at high-risk, either locally advanced or metastatic. ADT can be achieved through orchiectomy (surgical castration), luteinizing hormone-releasing hormone (LHRH) agonists, or through complete androgen blockade (LHRH agonist combined with an anti-androgen). Docetaxel in combination with prednisone or prednisolone is indicated for the treatment of patients with hormone-refractory metastatic prostate cancer. The CHAARTED and STAMPEDE clinical trials studied the effect of bringing forward the use of docetaxel added on to ADT in the context of hormone-sensitive patients. The CHAARTED clinical trial showed a significant increase in a variable with maximum relevance such as Overall Survival (OS), with a difference of 13.6 months between medians. There was also clinical benefit in the secondary variables: median time until castration-resistant disease or until clinical progression. In the STAMPEDE clinical trial, which included 39% of non-metastatic patients, a 10-month difference between medians was demonstrated in OS, and 17 months in the primary co-variable of Progression Free Survival. The most frequent adverse events were: neutropenia, febrile neutropenia, leucopenia, and general disorders such as asthenia, lethargy or fever. According to data from the CHAARTED and STAMPEDE studies, and the incremental cost of € 3 196.98 for adding on docetaxel to standard treatment, the estimated additional cost for each year of life gained is compatible with an incremental cost-effectiveness ratio between € 2 26736 and € 3 851.78. In view of the efficacy and safety results, the proposed positioning is: to advance the use of docetaxel added to androgen deprivation therapy to first-line metastatic hormone-sensitive prostate cancer, regardless of metastatic volume, in those patients who meet the CHAARTED study criteria.

Narirutin. A flavonoid found in citrus fruits modulates cell cycle phases and inhibits the proliferation of hormone-refractory prostate cancer cells by targeting hyaluronidase.

Narirutin is a dietary flavanone found in lemons, oranges, passion fruit, bergamot and grapefruit. It possesses anti-allergic, cardioprotective, neuroprotective, hepatoprotective potential, and its enriched fraction suppresses the growth of prostate cancer cells; however, there is currently no information on the chemopreventive potential of narirutin alone against hormone-refractory prostate cancer cells (PC-3) and its mode of action. Thus, the chemopreventive possibility of narirutin was investigated in PC-3cells by utilising cytotoxicity assays. Further, a mechanism was deduced targeting hyaluronidase, an early-stage diagnosis marker, by cell-free, cell-based and in silico studies. The results indicate that narirutin reduced the viability of PC-3cells with the inhibitory concentration range of 66.87-59.80μM. It induced G0/G1 phase arrest with a fold change of 1.12. Besides, it increased the generation of reactive oxygen species (ROS) with a fold change of 1.34at 100μM. Narirutin inhibited hyaluronidase's activity in cell-free (11.17μM) and cell-based assays (67.23μM) and showed a strong binding interaction with hyaluronidase. Finally, the MD simulation analysis supported the idea that narirutin binding enhanced compactness and stability and created a stable complex with hyaluronidase. In addition, ADMET prediction indicates that it is a non-toxic, non-CYPs inhibitor and thus didn't alter the metabolism. The results reveal that narirutin may be a potential chemopreventive agent for hormone-resistant prostate cancer cells in addition to offering data for supporting diet-based nutraceutical agents to prevent prostate cancer.

Cannabidiol alters mitochondrial bioenergetics via VDAC1 and triggers cell death in hormone-refractory prostate cancer

In spite of the huge advancements in both diagnosis and interventions, hormone refractory prostate cancer (HRPC) remains a major hurdle in prostate cancer (PCa). Metabolic reprogramming plays a key role in PCa oncogenesis and resistance. However, the dynamics between metabolism and oncogenesis are not fully understood. Here, we demonstrate that two multi-target natural products, cannabidiol (CBD) and cannabigerol (CBG), suppress HRPC development in the TRansgenic Adenocarcinoma of the Mouse Prostate (TRAMP) model by reprogramming metabolic and oncogenic signaling. Mechanistically, CBD increases glycolytic capacity and inhibits oxidative phosphorylation in enzalutamide-resistant HRPC cells. This action of CBD originates from its effect on metabolic plasticity via modulation of VDAC1 and hexokinase II (HKII) coupling on the outer mitochondrial membrane, which leads to strong shifts of mitochondrial functions and oncogenic signaling pathways. The effect of CBG on enzalutamide-resistant HRPC cells was less pronounced than CBD and only partially attributable to its action on mitochondria. However, when optimally combined, these two cannabinoids exhibited strong anti-tumor effects in TRAMP mice, even when these had become refractory to enzalutamide, thus pointing to their therapeutical potential against PCa.

From Terror to Treatment: a History of Human Castration

Objectives Castration is any action, surgical or chemical, by which an individual loses use of the gonads, most commonly referring to loss of the testicles. Reference to elective castration has been, according to Diodorus, as old as the human record itself, first being practiced in pharaonic Egypt. Castration has been practiced as a means to produce eunuchs, a punitive measure in military and secular courts, and a source of trophy-taking in warfare. The role of castration in the control of advanced and metastatic prostate cancer became a well recognized standard of care in the mid-20th century earning Nobel Prizes for its pioneers. Our aim was to better understand the history of human castration and its transformation from an instrument of terror to a standard and sometimes life-saving urological treatment. Methods A literature review on human castration was performed through Medline, PubMed, the Gutenburg Project, and Google Scholar searching words “castration”, “eunuch”, “orchiectomy” and “androgen deprivation”. We accessed the public archives of the British Museum (London) and digital classical libraries as cited. Reports were collected to create a timeline. Results First reports of human castration date back to the 21st century (BCE) in the ancient city of Lagash, Sumeria when used for the creation of court eunuchs. Castration figured prominently in most ancient cultures from myth to jurisprudence. The god Uranus was castrated by his son, Cronus (Saturn), with an adamantine sickle, throwing the severed gonads into the sea. There is at least conjectural evidence of castration on medical, criminal, and even volitional grounds from pharaonic and classical history through medieval and modern times. Primitive medical observations recognized the different phenotypes of pre-pubertal and post-pubertal eunuchs especially on the voice which may account for the popularity of some castrati in the history of choral music. Castration was a well-established procedure in the domestication of animals for millennia but it was only in 1941 that Charles Huggins and others first demonstrated the effects of bilateral orchiectomy in the control of prostate cancer. Medical castration, now with special androgen receptor inhibitors, continues to be a mainstay in the management of metastatic and hormone refractory prostate cancer. Conclusions Medical or surgical castration plays an important role in the modern management of advanced prostate cancer. Castration has existed in human cultures for thousands of years, although its true prevalence is unknown, accounted for in the folklore and sparse records typical of ancient times.

Suppression of prostate cancer and amelioration of the immunosuppressive tumor microenvironment through selective immunoproteasome inhibition

ABSTRACT New treatment options to battle hormone-refractory prostate carcinoma (PC) are a pressing medical need. Chronic inflammation has been implicated in PC etiology. The pro-inflammatory cytokines IL-6, IL-23 and IL-17 are key mediators to promote growth of PC. Here, we evaluate the potential of immunoproteasome inhibition for anti-inflammatory and direct anti-tumorigenic therapy of PC. The anti-tumor effect of immunoproteasome inhibitor ONX 0914 was tested in mouse and human PC cells and the in vivo therapeutic efficacy of immunoproteasome inhibition was analyzed in transgenic adenocarcinoma of the mouse prostate (TRAMP) mice in preventive and therapeutic settings and in castration-resistant (CR)PC after castration. Inhibition of the immunoproteasome subunit LMP7 induced apoptotic cell death in PC cell lines. In TRAMP mice, ONX 0914-treatment resulted in significant inhibition of PC growth with a decreased frequency of malignant prostatic lesions and inhibition of metastasis formation. The number of immunosuppressive myeloid cells in PC was greatly reduced in response to ONX 0914. Thus, immunoproteasome inhibition shows remarkable efficacy against PC progression in vivo and impedes tumor recurrence in CRPC-TRAMP mice by blocking the immunosuppressive inflammatory response in the tumor microenvironment. In conclusion, we show that the immunoproteasome is a promising drug target for the treatment of PC.

Macromolecular NO-Donor Micelles for Targeted and Augmented Chemotherapy against Prostate Cancer.

Mitoxantrone (MTO) is clinically utilized for treating hormone-refractory prostate cancer (PCa), however, the therapeutic outcome is far from optimal due to the lack of proper drug carrier as well as the inherent MTO detoxification mechanisms of DNA lesion repair and anti-oxidation. Herein, a bombesin-installed nanoplatform combining the chemotherapeutic MTO and the chemotherapeutic sensitizer of nitric oxide (NO) is developed based on MTO-loaded macromolecular NO-donor-containing polymeric micelles (BN-NMMTO ) for targeted NO-sensitized chemotherapy against PCa. BN-NMMTO actively target and accumulates in PCa sites and are internalized into the tumor cells. The macromolecular NO-donor of BN-NMMTO undergoes a reductive reaction to unleash NO upon intracellular glutathione (GSH), accompanying by micelle swelling and MTO release. The targeted intracellular MTO release induces DNA lesion and reactive oxygen species (ROS) generation in tumor cells without damage to the normal cells, and MTO's cytotoxicity is further augmented by NO release via the inhibition of both DNA repair and anti-oxidation pathways as compared with traditional MTO therapies.

The effect of mesenchymal stem cells-derived exosomes on the prostate, bladder, and renal cancer cell lines

We aimed to explain the role of mesenchymal stem cells (MSC-exosomes) on gene expressions of epithelial to mesenchymal transition (EMT), angiogenesis, and apoptosis. Four different cell lines were employed, including ACHN, 5637, LNCaP, and PC3, as well-known representatives for renal, bladder, hormone-sensitive, and hormone-refractory prostate cancers, respectively. Cell lines were exposed to diverse concentrations of mesenchymal stem cells-derived exosomes to find IC50 values. Percentages of apoptotic cells were evaluated by Annexin/P.I. staining. Micro Culture Tetrazolium Test assessed proliferative inhibitory effect; and prostate biomarker (KLK2), EMT (E-cadherin and Snail), angiogenesis genes (VEGF-A/VEGF-C), apoptosis genes (BAX/BCL2, P53) and Osteopontin variants (OPNa/b, and c) mRNA levels were studied by realtime PCR method. All 5637, LNCaP, and PC3 following treatment with exosomes illustrated specific responses with changes in expression of different genes. The increased TP53 and decreased BCL2 expressions were seen in 5637, LNCaP, and PC3. In PC3, OPNb and OPNc have raised more than P53; in LNCap, the increase was in VEGF-c. In 5637 cells, more than TP53 and BCL2 changes, two other genes, VEGFa and B.A.X., have decreased, suggesting exosomes’ anti-apoptotic and anti-angiogenic effects. The kidney tumor cell line saw no significant gene expression change in ten targeted genes. MSC-exosomes therapy has augmented some interesting antitumor effects on prostate, bladder, and kidney cancer cell lines. This effect which originates from exosomes’ potency to persuade apoptosis and prevent the proliferation of cancer cells simultaneously, was more substantial in bladder cancer, moderate in prostate cancer, and mild in renal cancer.

Polygodial, a Sesquiterpene Dialdehyde, Activates Apoptotic Signaling in Castration-Resistant Prostate Cancer Cell Lines by Inducing Oxidative Stress.

Prostate cancer (PCa) is the second leading cause of cancer death among men in the United States. Surgery, radiation therapy, chemotherapy, and androgen deprivation therapy are currently the standard treatment options for PCa. These have poor outcomes and result in the development of castration-resistant prostate cancer (CRPC), which is the foremost underlying cause of mortality associated with PCa. Taxanes, diterpene compounds approved to treat hormonal refractory PCa, show poor outcomes in CRPC. Polygodial (PG) is a natural sesquiterpene isolated from water pepper (Persicaria hydropiper), Dorrigo pepper (Tasmannia stipitata), and mountain pepper (Tasmannia lanceolata). Previous reports show that PG has an anticancer effect. Our results show that PG robustly inhibits the cell viability, colony formation, and migration of taxane-resistant CRPC cell lines and induces cell cycle arrest at the G0 phase. A toxicity investigation shows that PG is not toxic to primary human hepatocytes, 3T3-J2 fibroblast co-cultures, and non-cancerous BPH-1 cells, implicating that PG is innocuous to healthy cells. In addition, PG induces oxidative stress and activates apoptosis in drug-resistant PCa cell lines. Our mechanistic evaluation by a proteome profiler-human apoptotic array in PC3-TXR cells shows that PG induces upregulation of cytochrome c and caspase-3 and downregulation of antiapoptotic markers. Western blot analysis reveals that PG activates apoptotic and DNA damage markers in PCa cells. Our results suggest that PG exhibits its anticancer effect by promoting reactive oxygen species generation and induction of apoptosis in CRPC cells.

The effect of ciprofloxacin on doxorubicin cytotoxic activity in the acquired resistance to doxorubicin in DU145 prostate carcinoma cells.

The present study aimed to assess the influence of ciprofloxacin (CIP) against the doxorubicin (DOX)-resistant androgen-independent prostate cancer DU145 cells. The DOX-resistant DU145 (DU145/DOX20) cells were established by exposing DU145 cells to the increasing concentrations of DOX. The antiproliferative effect of CIP was examined through employing MTT, colony formation, and 3D culture assays. DU145/DOX20 cells exhibited a twofold higher IC50 value for DOX, an increased ABCB1 transporter activity, and some morphological changes accompanied by a decrease in spheroid size, adhesive and migration potential compared to DU145 cells. CIP (5 and 25µgmL-1) resulted in a higher reduction in the viability of DU145/DOX20 cells than in DU145 cells. DU145/DOX20 cells were more resistant to CIP in 3D culture compared to the 2D one. No spheroid formation was observed for DU145/DOX20 cells treated with DOX and CIP combination. CIP and DOX, alone or in combination, significantly reduced the growth of DU145 spheroids. CIP in combination with 20nM DOX prevented the colony formation of DU145 cells. The clonogenicity of DU145/DOX20 cells could not be estimated due to their low adhesive potential. CIP alone caused a significant reduction in the migration of DU145 cells and resulted in a more severe decrease in the wound closure ability of DOX-exposed ones. We identified that CIP enhanced DOX sensitivity in DU145 and DU145/DOX20 cells. This study suggested the co-delivery of low concentrations of CIP and DOX may be a promising strategy in treating the DOX-resistant and -sensitive hormone-refractory prostate cancer.

Clinical Applications of PSMA PET Examination in Patients with Prostate Cancer.

Simple SummaryThe prostate specific membrane antigens, abbreviated as PSMAs, are type II membrane proteins that are highly ex-pressed on the surface of malignant prostate tissue in prostate cancer (PCa), particularly in aggressive, andro-gen-deprived, metastatic, and hormone-refractory PCa. Today, radionuclides that bind to these PSMA peptides are widely available for diagnostic and therapeutic purposes to specifically image and target prostate tumor cells at molec-ular level. In this descriptive review, we aimed to emphasize the usefulness of PSMA positron emission tomography (PET) examination in the management of patients with various stages of PCa. In addition, we outlined the main pitfalls and limitations of this scan to avoid misinterpretation of the results and to improve the decision making process in rela-tion to the patient’s further treatment. We concluded that PSMA PET examination in primary PCa patients has an es-sential role in the high-risk group. It is the new imaging standard in patients with in biochemical recurrence PCa and plays an important role in treatment decision. Furthermore, PSMA PET scan is a gold standard for the evaluation of PSMA targeted therapies in patients having progress of the disease. Future prospective studies, particularly on the im-pact of PSMA PET on therapy stratification, may further strengthen the role of PSMA in the treatment of PCa patients. With the progressive aging of the population in industrially developed countries, as well as advances in diagnostic and biopsy techniques and improvements in patient awareness, the incidence of prostate cancer (PCa) is continuously increasing worldwide. Therefore, PCa is currently considered as the second leading cause of tumor-related death. Early detection of the tumor and its metastasis is essential, as the rate of disease recurrence is high and occurs in 27% to 53% of all patients who underwent curative therapy with radical prostatectomy or local radiotherapy. In this regard, the prostate specific membrane antigens, abbreviated as PSMAs, are type II membrane proteins that are highly expressed on the surface of malignant prostate tissue in PCa, particularly in aggressive, androgen-deprived, metastatic, and hormone-refractory PCa, and they are inversely associated with the androgen level. Up to 95% of adenocarcinomas of the prostate express PSMA receptors on their surface. Today, radionuclides that bind to these PSMA peptides are widely accepted for diagnostic and therapeutic purposes to specifically image and target prostate tumor cells at the molecular level, a process referred to as targeted theranostics. Numerous studies have demonstrated that the integration of these peptides into diagnostic and therapeutic procedures plays a critical role in the primary staging and treatment decisions of especially high-risk PCa, expands therapeutic options for patients with advanced stage of prostate tumor, and prolongs patients’ survival rate. In this review article, we intend to briefly spotlight the latest clinical utilization of the PSMA-targeted radioligand PET imaging modality in patients with different stages of PCa. Furthermore, limitations and pitfalls of this diagnostic technique are presented.

Understanding the Current Therapeutic Landscape for Advanced Prostate Cancer (CME article)

Treatment of advanced prostate cancer has improved rapidly in the past two decades with the introduction of many new therapeutics including several entirely new therapeutic classes. Whereas androgen deprivation therapy was previously the first and only line of treatment available, modern therapy also routinely employs second generation anti-androgens, chemotherapy, immunotherapy, radiopharmaceuticals, bone modifying agents, and poly(ADP-ribose) polymerase (PARP) inhibitors, with a resulting substantial increase in patient survival. This review aims to summarize the current treatment landscape for advanced prostate cancer, with a particular focus on hormone refractory (also known as ‘castration resistant’) prostate cancer (HRPC), and we hope will serve as a practical guide for clinicians and trainees.

PTCH1 and AXIN2 modulation of AR copy number effects on AR gene overexpression in metastatic castration resistant prostate cancer (mCRPC).

e17026 Background: Androgen receptor (AR) signaling is a critical pathway in prostate cancer progression. Reactivation of the AR pathway is a key driver in mCRPC. Patients with mCRPC often develop resistance to novel AR signaling inhibitors (ARSIs) such as enzalutamide. AR inhibitor resistance leads to shorter overall and progression-free survival and can be attributed to AR gene amplification with subsequent AR overexpression and androgen-sensitization in prostate tumors. Identifying novel modulators of AR amplification in patients progressing on ARSIs may lead towards potential targets in drug discovery. Methods: In this cross-sectional study, an in silico patient model was developed on prescribed drug therapies and failed therapies patient information, PSA measures, ̃100 mutation variables including somatic, germline, and gain/loss mutations, and ̃1K gene expressions data from 275 mCRPC patients obtained from the Tempus database using GNS Healthcare’s Causal artificial intelligence technology, REFS. A causal network model was reconstructed based on patient data with inferred effect estimates. The network model was topologically surveyed for biological interactions. Results: Causal analysis of this model uncovered two germline mutations, located in PTCH1 and AXIN2, which modify the effect of AR copy number gain ( ARgain+ : copy number 6, ARgain- : copy number < 6) on AR gene expression. For PTCH1-mutant group, there was a 2-fold increase in AR gene expression in ARgain+ patients compared to ARgain- patients (p = 2.1e-12), while only 1.4 fold increase in AR gene expression from the PTCH1 non-mutant group (p = 6.3e-08). Similarly, there was a 2-fold increase in AR gene expression in ARgain+ patients compared to ARgain- patients (p = 7.2e-16) for the AXIN2-mutant group, while only one-fold increase in AR gene expression with the AXIN2 non-mutant group (p = 0.001). The C to T missense mutation in codon 3746 in PTCH1 and codon 148 in AXIN2 have higher prevalences, 55% and 72%, respectively in this mCRPC cohort compared to their population allele frequencies, 38% and 47%, respectively. Conclusions: PTCH1 and AXIN2 mutations from our analyses is consistent with a literature reported role for Hedgehog signaling and Wnt/-catenin signaling pathways, respectively, influencing the disease progression in castration-resistant prostate cancer. Our findings suggest that the missense germline mutations in PTCH1 and AXIN2 predicts response to enzalutamide and other ARSIs in CRPC setting, and propose potential targets for combination therapy to overcome ARSI drug resistance in hormone-refractory prostate cancer. [Table: see text]

Glucocorticoid Receptor Beta as a Contributor to Prostate Cancer Growth and Migration

Adenocarcinoma of the prostate is commonly diagnosed in the United States. Prostate cancer (PC) is second only to lung cancer as a leading cause of male cancer deaths (CDC & NCI). African‐Americans (AA) are nearly 1.6 times more likely to be diagnosed with PC than Caucasian‐American (CA) men and 2.4 times more likely to die from the disease. There are known growth‐inhibitory roles of glucocorticoid (GC) hormones in PC. However, eventually, the PC growth and the disease “escapes” become refractory to hormone therapy. Glucocorticoid receptor (GR) consists of two isoforms, GRα, which has been the most studied, and another isoform, GRβ, is less understood. The role of GRβ or GRα in the spectrum of the disease of prostate adenocarcinoma is unknown. Previously, our lab discovered the GRβ gene in mice and found that GRβ has a role in enhancing the growth of cancer cells via the PTEN/Akt1 pathway. In our studies, we found high levels of GRβ in adenocarcinomas from prostate cancer specimens and no change in the GRα level. Analysis of E006AA prostate cancer cells from African Americans showed significantly higher GRβ levels (p<0.01) compared to cells from Caucasian Americans. We, therefore, used lentivirus to overexpress GRβ in LNCaP cells that are derived from Caucasian men. We found that GRβ induces growth pathways and sensitizes to androgen‐induced growth. Migration studies in the E006AA prostate cancer cells from African Americans showed that antagonizing GRβ by lentiviral shRNA or by the Sweet‐P inhibitor significantly (p<0.05) decreased migration rates of the prostate cancer cells. Our findings here indicate that GRβ inhibits GRα to cause GC resistance, which may cultivate hormone‐refractory PC for growth and migration. The research findings may impact PC treatment by allowing for the development of strategies for rational drug design that may lead to novel treatments targeting GRβ and provide the basis for studies in the management of prostate cancer.

Lipophagy-Related Protein Perilipin-3 and Resistance of Prostate Cancer to Radiation Therapy

Radiation therapy is a principal treatment modality for localized and locally advanced prostate cancer (PCa). Metabolic alterations, including lipid metabolism, may reduce treatment efficacy, resulting in tumor relapse and poor therapeutic outcome. In the current study, we investigated the role of the lipophagy-related protein perilipin-3 (PLIN3) and the lysosomal acid lipase (LAL) in PCa response to radiation therapy. We explored the in vitro and xenograft (in NOD SCID and R2G2 mice) response to radiation of either PLIN3-depleted or LAL-depleted hormone-refractory (DU145, PC3) and hormone-responsive (22Rv1) PCa cell lines. Moreover, we evaluated the clinical role of PLIN3 and LAL protein expression in a series of PCa tissue specimens from patients treated with radical radiation therapy. In vitro and in vivo experiments showed reduced proliferation and strong radiosensitization of all studied PCa cell lines upon PLIN3 depletion. In vivo experiments demonstrated the significantly augmented radiation therapy efficacy upon PLIN3 depletion, resulting in extensive tissue necrosis. Overexpression of PLIN3 in tissue specimens was correlated with an increased MIB1 proliferation index, increased autophagy flux, reduced response to radiation therapy, and poor prognosis. The effect of LAL depletion on radiation therapy was of lesser importance. Assessment of PLIN3 expression may identify subgroups of patients with PCa who are less responsive to radiation therapy and at high risk of relapse after irradiation. Whether radiation therapy efficacy may be enhanced by concurrent autophagy or PLIN3 inhibition in this subgroup of patients demands clinical evaluation.

Caffeic acid phenethyl ester induces radiosensitization via inhibition of DNA damage repair in androgen-independent prostate cancer cells.

In the present study, we evaluated the radiomodulatory potential of caffeic acid phenethyl ester (CAPE), an active component of traditional herbal medicine propolis. CAPE has been identified as a potent anticancer agent in multiple cancer types and is reported to have the dual role of radioprotection and radiosensitization. However, the radiomodulatory potential of CAPE in prostate cancer (PCa), which eventually becomes radioresistant is not known. Therefore, we studied the effect of co-treatment of CAPE and gamma radiation on androgen-independent DU145 and PC3 cells. The combination treatment sensitized PCa cells to radiation in a dose-dependent manner. The radiosensitizing effect of CAPE was observed in both cell lines. CAPE enhanced the level of ionizing radiation (IR)-induced gamma H2AX foci and cell death by apoptosis. The combination treatment also decreased the migration potential of PCa cells. This was confirmed by increased expression of E-cadherin and decrease in vimentin expression. CAPE sensitized PCa cells to radiation in vitro and induced apoptosis, augmented phosphorylation of Akt/mTOR, and hampered cell migration. At the mechanistic level, co-treatment of CAPE and IR inhibited cell growth by decreasing RAD50 and RAD51 proteins involved in DNA repair. This resulted in enhanced DNA damage and cell death. CAPE might represent a promising new adjuvant for the treatment of hormone-refractory radioresistant PCa.

THERAGNOSTICS OF SAMARIUM-153-EDTMP IN PATIENTS BEARING PROSTATE CANCER AND OSSEOUS SECONDARIES: PALLIATIVE BUT ALSO TUMOURICIDAL

BACKGROUND: 153 The radionuclide samarium-153 ( Sm) in a chelated compound with ethylene-diamine-tetramethylene phosphonate (EDTMP) is mainly used as an alternative to palliative therapy of multifocal painful osseous metastases due to various primaries, especially 153 prostate, breast, lung cancer, and osteosarcoma. Considering novel aspects of chemical properties attributed to Sm, we aimed at evaluating the 153 outcomes of solitary versus repeated Sm-EDTMPor exclusive opiate therapy in patients with osseous secondaries from prostate cancer. MATERIALS AND METHODS: In the present retrospective study, we included three groups of patients with hormone-refractory prostate cancer (HRPC) and multiple painful osteoblastic or mixed secondaries conrmed by bone scintigraphy. Forty-three patients (Group A) received 2 153 consecutive intravenous (i.v.) administrations of Sm-EDTMP (37 MBq/kg of body weight each), twelve patients (Group B) received a solitary 153 i.v. dose Sm-EDTMP and 12 patients (Group C) used solely opiates due to exclusion criteria regarding radiometabolic therapy. RESULTS: 153 Pain palliation was reported by 90.7% of group Apatients after the second injection. The repeated dose of Sm-EDTMPimproved the duration of pain response to 24±6 versus 8±2 weeks of the single dose treatment plan, without signicant myelotoxicity. Group C patients were considered as non-responders owing to increased pain score and consumption of analgesics. CONCLUSION: 153 Arepeated-dose Sm-EDTMPtreatment scheme consistently provides enhanced pain alleviation, thereby preserving quality of 153 life in patients with skeletal metastases from HRPC. Interestingly, radiometabolic therapy with Sm-EDTMP effectuates tumouricidal implications, thus upgrading a palliative agent to a disease theragnostics-targeted modier, with anticipated survival benet.

AQbD Driven Development of an RP-HPLC Method for the Quantitation of Abiraterone Acetate for its Pharmaceutical Formulations in the Presence of Degradants

Abiraterone acetate is a well-known anticancer drug and a steroidal derivative of progesterone for treatment of patients with hormone-refractory prostate cancer. Chemometrics-assisted reverse phase high performance liquid chromatography (RP-HPLC) development of the drug abiraterone acetate has been employed in this study using an analytical quality by design (AQbD) approach. Drug separation was performed using a Princeton Merck-Hibar Purospher STAR (C18, 250 mm × 4.6 mm) i.d., 5 μm particle size) with ultraviolet detection at 235 nm. A Box-Behnken statistical experimental design with response surface methodology was executed for method optimization and desired chromatographic separation from its formulation with a few numbers of experimental trials. The impact of three independent variables, namely, composition of the mobile phase, pH, and flow rate, on response retention time and peak area was studied by constructing an arithmetic model from these variables. Optimized experimental conditions for the proposed work include the mobile phase acetonitrile and phosphate buffer (10 mM KH2PO4) (20:80 %v/v). At the concentration range of 2-100 μg/mL, a linear calibration curve was found. Recovery was performed at three concentrations and was foun to be between 98% and 102%. The 3D response surface curves revealed that mobile phase composition and flow rate were the most substantial critical factors affecting desired responses. An attempt has been made to develop and validate an economical, precise, robust, stability-indicating AQbD-based RP-HPLC method that can be employed successfully for the routine analysis of abiraterone acetate in quality control labs.

Robust group sequential designs for trials with survival endpoints and delayed response.

Randomized clinical trials in oncology typically utilize time-to-event endpoints such as progression-free survival or overall survival as their primary efficacy endpoints, and the most commonly used statistical test to analyze these endpoints is the log-rank test. The power of the log-rank test depends on the behavior of the hazard ratio of the treatment arm to the control arm. Under the assumption of proportional hazards, the log-rank test is asymptotically fully efficient. However, this proportionality assumption does not hold true if there is a delayed treatment effect. Cancer immunology has evolved over time and several cancer vaccines are available in the market for treating existing cancers. This includes sipuleucel-T for metastatic hormone-refractory prostate cancer, nivolumab for metastatic melanoma, and pembrolizumab for advanced nonsmall-cell lung cancer. As cancer vaccines require some time to elicit an immune response, a delayed treatment effect is observed, resulting in a violation of the proportional hazards assumption. Thus, the traditional log-rank test may not be optimal for testing immuno-oncology drugs in randomized clinical trials. Moreover, the new immuno-oncology compounds have been shown to be very effective in prolonging overall survival. Therefore, it is desirable to implement a group sequential design with the possibility of early stopping for overwhelming efficacy. In this paper, we investigate the max-combo test, which utilizes the maximum of two weighted log-rank statistics, as a robust alternative to the log-rank test. The new test is implemented for two-stage designs with possible early stopping at the interim analysis time point. Two classes of weights are investigated for the max-combo test: theFleming and Harrington (1981) weights and theMagirr and Burman (2019) modest weights.

Humanization, Radiolabeling and Biodistribution Studies of an IgG1-Type Antibody Targeting Uncomplexed PSA for Theranostic Applications.

Metastatic castration-resistant prostate cancer is today incurable. Conventional imaging methods have limited detection, affecting their ability to give an accurate outcome prognosis, and current therapies for metastatic prostate cancer are insufficient. This inevitably leads to patients relapsing with castration-resistant prostate cancer. Targeting prostate-specific antigens whose expression is closely linked to the activity in the androgen receptor pathway, and thus the pathogenesis of prostate cancer, is a possible way to increase specificity and reduce off-target effects. We have humanized and evaluated radioimmunoconjugates of a previously murine antibody, m5A10, targeting PSA intended for theranostics of hormone-refractory prostate cancer. The humanized antibody h5A10 was expressed in mammalian HEK293 cells transfected with the nucleotide sequences for the heavy and light chains of the antibody. Cell culture medium was filtered and purified by Protein G chromatography, and the buffer was changed to PBS pH 7.4 by dialysis. Murine and humanized 5A10 were conjugated with p-SCN-Bn-CHX-A”-DTPA. Surface plasmon resonance was used to characterize the binding to PSA of the immunoconjugates. Immunoconjugates were labeled with either indium-111 or lutetium-177. Biodistribution studies of murine and humanized 5A10 were performed in mice with LNCaP xenografts. 5A10 was successfully humanized, and in vivo targeting showed specific binding in xenografts. The results thus give an excellent platform for further theranostic development of humanized 5A10 for clinical applications.