A phase I dose-escalation study of enzalutamide in combination with the AKT inhibitor AZD5363 (capivasertib) in patients with metastatic castration-resistant prostate cancer

A Meta-analysis of the Risk of Adverse Cardiovascular Events in Patients with Cancer Treated with Inhibitors of the PI3K/AKT/mTOR Signaling Pathway

With the increasing of PI3K/AKT/mTOR (PAM) inhibitors in cancer therapy, there is a growing need to understand the incidence of cardiovascular events (CVAEs) associated with PAM inhibitors. A systematic search of all randomized clinical trials (RCTs) containing at least one PAM group in electronic databases such as PubMed, ClinicalTrials.gov registry, Embase, Medline, Cochrane Library, and major conferences was performed to extract available CVAEs. The cut-off date was January 31, 2024. Study heterogeneity was assessed using the I2 statistic. The risk of CVAEs associated with PAM inhibitors was calculated using Peto OR. The primary outcome was the incidence (95% CI) of PAM inhibitors cardiovascular adverse events in the total population and subgroups. The secondary outcome was the pooled risk of different CVAEs associated with PAM inhibitor exposure in the RCTs. 33 unique RCTs (n = 12,351) were included. The incidence of PAM inhibitors CVAEs of any grade in the intervention group was 48.2%, yielding a combined OR of 2.52 (95% CI 1.82-3.49). The incidence of severe adverse cardiovascular events (≥ grade 3) in the intervention group was estimated at 7.1%, yielding a combined Peto OR of 1.41 (95% CI 1.04-1.93). PAM inhibitors were associated with an increased risk of 5 CVAEs including peripheral edema, lymphoedema, hypercholesterolemia, hypertriglyceridaemia and hyperlipidemia, with higher risks for hypercholesterolemia (Peto OR: 3.27,95% CI 2.61-4.11, P < 0.01; I2 = 55.5%, P = 0.06) and hyperlipidemia (Peto OR: 3.53. 95% CI 1.70-7.32, P < 0.01; I2 = 19.3%, P = 0.29). This study identified an overall incidence of PAM inhibitors CVAEs and the increased risks associated with PAM inhibitor for five specific CVAEs, not confined to hypercholesterolemia and peripheral edema.

The Emerging Predictive and Prognostic Role of Aggressive-Variant-Associated Tumor Suppressor Genes Across Prostate Cancer Stages

Aggressive variant prostate cancer (AVPC) is characterized by a molecular signature involving combined defects in TP53, RB1, and/or PTEN (AVPC-TSGs), identifiable through immunohistochemistry or genomic analysis. The reported prevalence of AVPC-TSG alterations varies widely, reflecting differences in assay sensitivity, treatment pressure, and disease stage evolution. Although robust clinical evidence is still emerging, the study of AVPC-TSG alterations in prostate cancer (PCa) is promising. Alterations in TP53, RB1, and PTEN, as well as the combined loss of AVPC-TSGs, may have significant implications for prognosis and treatment. These biomarkers might help predict responses to various therapies, including hormonal treatments, cytotoxic agents, radiotherapy, and targeted therapies. Understanding the impact of these molecular alterations in patients with PCa is crucial for personalized management. In this review, we provide a comprehensive overview of the emerging prognostic and predictive roles of AVPC-TSG alterations across PCa stages. Moreover, we discuss the implications of different methods used for detecting AVPC-TSG alterations and summarize factors influencing their prevalence. As our comprehension of the genomic landscape of PCa disease deepens, incorporating genomic profiling into clinical decision making will become increasingly important for improving patient outcomes.

Efficacy and Safety of Combination AKT and Androgen Receptor Signaling Inhibition in Metastatic Castration-Resistant Prostate Cancer: Systematic Review and Meta-Analysis

BACKGROUND

Metastatic castration-resistant prostate cancer (mCRPC) has a poor prognosis with current treatment options including chemotherapy and androgen receptor signaling inhibitor (ARSI) medications. Poly-ADP ribose polymerase (PARP) inhibitors alone and in combination with ARSI has recently been incorporated in management for mCRPC deficient in BRCA1/2 genes. However, downregulating androgen-receptor signaling using ARSIs can upregulate the PI3K/AKT/mTOR pathway, promoting tumor cell survival. This creates a rationale for co-targeting both these pathways. This systematic review aimed to investigate AKT inhibitors and ARSI combination therapy.

METHODS

EMBASE, MEDLINE, and Scopus were searched from database inception to July 2023. Primary outcomes included objective response rate (ORR), prostate-specific antigen (PSA) response rate, adverse events (AEs), overall survival (OS), and radiographic progression-free survival (rPFS). Quality was assessed using the risk of bias tool (ROB2) and certainty of evidence with GRADE.

RESULTS

Six clinical trials with 3 Phase I, 1 Phase II, 1 Phase III were included with 771 patients and a median age ranging from 67 years to 70 years. The pooled ORR was 30% (n = 5 studies, 95% CI, 3%-84%) and PSA response rate was 43% (n = 5 studies, 95% CI, 15%-77%). The median duration of rPFS ranged from 8.2 to 19.2 months in the intervention compared with 6.4 to 16.6 months in the placebo group. A 16% reduction in radiographic progression or death was reported in patients receiving dual therapy compared with those receiving placebo. This reduction was greater by PTEN-loss status, ranging from 23% to 61%. The median OS ranged from 15.6 to 18.9 months. No significant difference was reported in survival relative to placebo. 98.8% (767/776) of patients experienced AEs of any grade, with GRADE ≥3 AEs occurring in 65.9% (512/776) of patients. The most common AE and GRADE ≥3 AEs were diarrhoea (pooled prevalence = 70%, 95% CI, 57%-81%), and hyperglycaemia (pooled prevalence = 12%, 95% CI, 6%-20%), respectively.

CONCLUSION

Combined therapy reduced the risk of rPFS, with the response higher in PTEN-loss subgroup, with a modest but not significant increase in OS. Our AE estimates showed consistency with other studies. AEs of any grade were common with the majority experiencing at least 1 AE. (PROSPERO Registration Number: CRD420202352583).

Important Roles of PI3K/AKT Signaling Pathway and Relevant Inhibitors in Prostate Cancer Progression

Prostate cancer (PCa) is an extremely common malignant tumor of the male genitourinary system, originating from the prostate gland epithelium. Male patients are prone to relapse after treatment, which seriously threatens their health. Phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as Akt) plays an important role in the growth, invasion, and metastasis of PCa. This review aimed to present an overview of the mechanism of action of the PI3K/AKT signaling pathway in PCa and discuss the application prospects of inhibitors of this pathway in treating PCa, providing a theoretical basis and reference for its clinical treatment targets.

PLXNA1 confers enzalutamide resistance in prostate cancer via AKT signaling pathway

Although targeting the androgen signaling pathway by androgen receptor (AR) inhibitors, including enzalutamide, has shown therapeutic effectiveness, inevitable emergence of acquired resistance remains a critical challenge in the treatment of advanced prostate cancer (PCa). Recognizing targetable genomic aberrations that trigger endocrine treatment failure holds great promise for advancing therapeutic interventions. Here, we characterized PLXNA1, amplified in a subset of PCa patients, as a contributor to enzalutamide resistance (ENZR). Elevated PLXNA1 expression facilitated PCa proliferation under enzalutamide treatment due to AKT signaling activation. Mechanistically, PLXNA1 recruited NRP1 forming a PLXNA1-NRP1 complex, which in turn potentiated the phosphorylation of the AKT. Either inhibiting PLXNA1-NRP1 complex with an NRP1 inhibitor, EG01377, or targeting PLXNA1-mediated ENZR with AKT inhibitors, abolished the pro-resistance phenotype of PLXNA1. Taken together, combination of AKT inhibitor and AR inhibitors presents a promising therapeutic strategy for PCa, especially in advanced PCa patients exhibiting PLXNA1 overexpression.

Capivasertib in Hormone Receptor-Positive, Human Epidermal Growth Factor Receptor 2-Negative advanced breast cancer

PURPOSE

This review discusses the role and efficacy of Capivasertib in managing Hormone Receptor-Positive (HR+) breast cancer.

SUMMARY

Breast cancer is the most prevalent type of cancer among women worldwide. This article is an in-depth analysis of advanced therapeutic options involving Capivasertib in treating HR+ Breast Cancer. It focuses on the mode of action, efficacy, clinical trials, and comparison with fulvestrant alone. This review also highlights the therapy's precision in targeting specific cancer cells. Its mechanism of action involves preventing cancer cells from growing and having a cytotoxic effect on them. It improves progression-free survival while maintaining the quality of life. The side effects can be easily managed by dose reduction or discontinuation of the drug. This article sheds light on the ongoing trials and FDA recognition.

CONCLUSION

In conclusion, Capivasertib-fulvestrant therapy shows potential as an innovative therapeutic option for HR+ breast cancer but warrants additional research, especially in randomized control trials (RCT). It resulted in longer progression-free survival compared to fulvestrant alone. Its side effect profile is minimal.

Capivasertib in combination with enzalutamide for metastatic castration resistant prostate cancer after docetaxel and abiraterone: Results from the randomized phase II RE-AKT trial

BACKGROUND

PTEN loss and aberrations in PI3K/AKT signaling kinases associate with poorer response to abiraterone acetate (AA) in metastatic castration-resistant prostate cancer (mCRPC). In this study, we assessed antitumor activity of the AKT inhibitor capivasertib combined with enzalutamide in mCRPC with prior progression on AA and docetaxel.

METHODS

This double-blind, placebo-controlled, randomized phase 2 trial, recruited men ≥ 18 years with progressing mCRPC and performance status 0-2 from 15 UK centers. Randomized participants (1:1) received enzalutamide (160 mg orally, once daily) with capivasertib (400 mg)/ placebo orally, twice daily on an intermittent (4 days on, 3 days off) schedule. Primary endpoint was composite response rate (RR): RECIST 1.1 objective response, ≥ 50 % PSA decrease from baseline, or circulating tumor cell count conversion (from ≥ 5 at baseline to < 5 cells/7.5 mL). Subgroup analyses by PTENIHC status were pre-planned.

RESULTS

Overall, 100 participants were randomized (50:50); 95 were evaluable for primary endpoint (47:48); median follow-up was 43 months. RR were 9/47 (19.1 %) enzalutamide/capivasertib and 9/48 (18.8 %) enzalutamide/placebo (absolute difference 0.4 % 90 %CI -12.8 to 13.6, p = 0.58), with similar results in the PTENIHC loss subgroup. Irrespective of treatment, OS was significantly worse for PTENIHC loss (10.1 months [95 %CI: 4.6-13.9] vs 14.8 months [95 %CI: 10.8-18]; p = 0.02). Most common treatment-emergent grade ≥ 3 adverse events for the combination were diarrhea (13 % vs 2 %) and fatigue (10 % vs 6 %).

CONCLUSIONS

Combined capivasertib/enzalutamide was well tolerated but didn't significantly improve outcomes from abiraterone pre-treated mCRPC.

Innovative Drug Modalities for the Treatment of Advanced Prostate Cancer

Prostate cancer, a prevalent malignancy affecting the prostate gland, is a significant global health concern. Androgen-deprivation therapy (ADT) has proven effective in controlling advanced disease, with over 50% of patients surviving at the 10-year mark. However, a diverse spectrum of responses exists, and resistance to ADT may emerge over time. This underscores the need to explore innovative treatment strategies for effectively managing prostate cancer progression. Ongoing research endeavors persist in unraveling the complexity of prostate cancer and fostering the development of biologic and innovative approaches, including immunotherapies and targeted therapies. This review aims to provide a valuable synthesis of the dynamic landscape of emerging drug modalities in this context. Interestingly, the complexities posed by prostate cancer not only present a formidable challenge but also serve as a model and an opportunity for translational research and innovative therapies in the field of oncology.

New clinical trial design in precision medicine: discovery, development and direction

In the era of precision medicine, it has been increasingly recognized that individuals with a certain disease are complex and different from each other. Due to the underestimation of the significant heterogeneity across participants in traditional "one-size-fits-all" trials, patient-centered trials that could provide optimal therapy customization to individuals with specific biomarkers were developed including the basket, umbrella, and platform trial designs under the master protocol framework. In recent years, the successive FDA approval of indications based on biomarker-guided master protocol designs has demonstrated that these new clinical trials are ushering in tremendous opportunities. Despite the rapid increase in the number of basket, umbrella, and platform trials, the current clinical and research understanding of these new trial designs, as compared with traditional trial designs, remains limited. The majority of the research focuses on methodologies, and there is a lack of in-depth insight concerning the underlying biological logic of these new clinical trial designs. Therefore, we provide this comprehensive review of the discovery and development of basket, umbrella, and platform trials and their underlying logic from the perspective of precision medicine. Meanwhile, we discuss future directions on the potential development of these new clinical design in view of the "Precision Pro", "Dynamic Precision", and "Intelligent Precision". This review would assist trial-related researchers to enhance the innovation and feasibility of clinical trial designs by expounding the underlying logic, which be essential to accelerate the progression of precision medicine.

Acquired copy number variation in prostate tumours: a review of common somatic copy number alterations, how they are formed and their clinical utility

Prostate cancer is one of the most commonly diagnosed cancers in men and unfortunately, disease will progress in up to a third of patients despite primary treatment. Currently, there is a significant lack of prognostic tests that accurately predict disease course; however, the acquisition of somatic chromosomal variation in the form of DNA copy number variants may help understand disease progression. Notably, studies have found that a higher burden of somatic copy number alterations (SCNA) correlates with more aggressive disease, recurrence after surgery and metastasis. Here we will review the literature surrounding SCNA formation, including the roles of key tumour suppressors and oncogenes (PTEN, BRCA2, NKX3.1, ERG and AR), and their potential to inform diagnostic and prognostic clinical testing to improve predictive value. Ultimately, SCNAs, or inherited germline alterations that predispose to SCNAs, could have significant clinical utility in diagnostic and prognostic tests, in addition to guiding therapeutic selection.

The kinesin-14 family motor protein KIFC2 promotes prostate cancer progression by regulating p65

The kinesin-14 motor proteins play important roles in tumor development and drug resistance and have been reported as potential biomarkers or therapeutic targets for tumor treatment. However, kinesin family member C2 (KIFC2), one of the kinesin-14 motor family members, remains largely unknown in prostate cancer (PCa) progression. Here, we used the GEO and The Cancer Genome Atlas datasets, Western blotting, and immunohistochemistry analyses to detect KIFC2 expression in PCa tissues. Additionally, a series of in vivo and in vitro experiments were utilized to demonstrate the roles of KIFC2 in PCa cells. We found that KIFC2 was highly expressed and positively correlated with the clinicopathological characteristics in PCa. Functional experiments indicated that KIFC2 could promote PCa progression. Furthermore, we performed an analysis of the KEGG and GSEA databases, subcellular fractionation, and immunofluorescence to investigate the potential mechanisms of KIFC2 in PCa. We confirmed that KIFC2 could regulate the NF-κB pathway via mediating NF-κB p65 protein expression and nuclear translocation thereby promoting PCa progression and chemotherapeutic resistance. Together, our results suggest that KIFC2 is overexpressed in PCa. By regulating the NF-κB pathway, KIFC2 may play a crucial role in PCa.

Genomic and Phenotypic Biomarkers for Precision Medicine Guidance in Advanced Prostate Cancer

OPINION STATEMENT

Prostate cancer (PCa) is the second most diagnosed malignant neoplasm and is one of the leading causes of cancer-related death in men worldwide. Despite significant advances in screening and treatment of PCa, given the heterogeneity of this disease, optimal personalized therapeutic strategies remain limited. However, emerging predictive and prognostic biomarkers based on individual patient profiles in combination with computer-assisted diagnostics have the potential to guide precision medicine, where patients may benefit from therapeutic approaches optimally suited to their disease. Also, the integration of genotypic and phenotypic diagnostic methods is supporting better informed treatment decisions. Focusing on advanced PCa, this review discusses polygenic risk scores for screening of PCa and common genomic aberrations in androgen receptor (AR), PTEN-PI3K-AKT, and DNA damage response (DDR) pathways, considering clinical implications for diagnosis, prognosis, and treatment prediction. Furthermore, we evaluate liquid biopsy, protein biomarkers such as serum testosterone levels, SLFN11 expression, total alkaline phosphatase (tALP), neutrophil-to-lymphocyte ratio (NLR), tissue biopsy, and advanced imaging tools, summarizing current phenotypic biomarkers and envisaging more effective utilization of diagnostic and prognostic biomarkers in advanced PCa. We conclude that prognostic and treatment predictive biomarker discovery can improve the management of patients, especially in metastatic stages of advanced PCa. This will result in decreased mortality and enhanced quality of life and help design a personalized treatment regimen.

LINC01088/miR-22/CDC6 Axis Regulates Prostate Cancer Progression by Activating the PI3K/AKT Pathway

Background

Prostate cancer (PCa) harms the male reproductive system, and lncRNA may play an important role in it. Here, we report that the LINC01088/microRNA- (miRNA/miR-) 22/cell division cycle 6 (CDC6) axis regulated through the phosphatidylinositide 3-kinases- (PI3K-) protein kinase B (AKT) signaling pathway controls the development of PCa.

Methods

lncRNA/miRNA/mRNA associated with PCa was downloaded and analyzed by Gene Expression Omnibus. The expression and correlation of LINC01088/miR-22/CDC6 in PCa were analyzed and verified by RT-qPCR. Dual-luciferase was used to analyze the binding between miR-22 and LINC01088 or CDC6. Cell Counting Kit-8 and Transwell were used to analyze the effects of LINC01088/miR-22/CDC6 interactions on PCa cell viability or migration/invasion ability. Localization of LINC01088 in cells was analyzed by nuclear cytoplasmic separation. The effect of LINC01088/miR-22/CDC6 interaction on downstream PI3K/AKT signaling was analyzed by Western blot.

Results

LINC01088 or CDC6 was upregulated in prostate tumor tissues or cells, whereas miR-22 was downregulated, miR-22 directly targets both LINC01088 and CDC6. si-LINC01088 inhibits the PCa process by suppressing the PI3K/AKT pathway. CDC6 reverses si-linc01088-mediated cell growth inhibition and reduction of PI3K and AKT protein levels.

Conclusion

Our results demonstrate that the LINC01088/miR-22/CDC6 axis functions in PCa progression and provide a promising diagnostic and therapeutic target.

Pomegranate-specific natural compounds as onco-preventive and onco-therapeutic compounds: Comparison with conventional drugs acting on the same molecular mechanisms

Pomegranate, scientifically known as Punica granatum, has been a traditional medicinal remedy since ancient times. Research findings have shown that using pomegranate extracts can positively affect a variety of signaling pathways, including those involved in angiogenesis, inflammation, hyperproliferation, cellular transformation, the beginning stages of tumorigenesis, and lastly, a reduction in the final stages of metastasis and tumorigenesis. This is due to the fact that pomegranate extracts are rich in polyphenols, which are known to inhibit the activity of certain signaling pathways. In the United States, cancer is the second biggest cause of death after heart disease. The number of fatalities caused by cancer in the United States escalates yearly. Altering one's diet, getting involved in regular physical activity, and sustaining a healthy body weight are three easy steps an individual may follow to lower their cancer risk. Simply garnishing one's diet with vegetables and fruits has the potential to avert at least 20% of all cancer diagnoses and around 200,000 deaths caused by cancer each year. Vegetables, fruits, and other dietary constituents, such as minerals and phytochemicals, are currently being researched for their potential to prevent cancer. It is being done because they are safe, have minimal toxicity, possess antioxidant properties, and are universally accepted as dietary supplements. Ancient civilizations used the fruit of pomegranate (Punica granatum L.) to prevent and cure a number of diseases. The anti-tumorigenic, anti-inflammatory and anti-proliferative qualities of pomegranate have been shown in studies with the fruit, juice, extract, and oil of the pomegranate. Pomegranate has the capacity to affect several signaling pathways, which implies that it may have the potential to be employed not only as a chemopreventive agent but also as a chemotherapeutic drug. This article elaborates on some recent preclinical and clinical research which shows that pomegranate seems to have a role in the prevention and treatment of a number of cancers, including but not limited to breast, bladder, skin, prostate, colon, and lung cancer, among others.

Metastatic Castration-Resistant Prostate Cancer: Insights on Current Therapy and Promising Experimental Drugs

The therapeutic landscape of metastatic hormone sensitive and metastatic castration-resistant prostate cancer (mCRPC) is rapidly changing. We reviewed the current treatment options for mCRPC, with insights on new available therapeutic strategies. Chemotherapy with docetaxel or cabazitaxel (for patients progressing on docetaxel), as well as treatment with androgen receptor axis targeted therapies, and Radium-223 are well-established treatment options for patients with mCRPC. The advent of theragnostic in prostate cancer established Lutetium-177 (177Lu)-PSMA-617 as a new standard of care for PSMA-positive mCRPC previously treated with ARAT and taxane-based chemotherapy. Olaparib, a poly-ADP-ribose polymerase (PARP) inhibitor, is approved for selected patients with mCRPC progressed on ARATs and in combination with abiraterone acetate as first-line treatment for mCRPC. Immunotherapy showed limited efficacy in unselected patients with mCRPC and novel immunotherapy strategies need to be explored. The search for biomarkers is a growing field of interest in mCRPC, and predictive biomarkers are needed to support the choice of treatment and the development of tailored strategies.

Virtual and In Vitro Screening of Natural Products Identifies Indole and Benzene Derivatives as Inhibitors of SARS-CoV-2 Main Protease (Mpro)

The rapid spread of the coronavirus disease 2019 (COVID-19) resulted in serious health, social, and economic consequences. While the development of effective vaccines substantially reduced the severity of symptoms and the associated deaths, we still urgently need effective drugs to further reduce the number of casualties associated with SARS-CoV-2 infections. Machine learning methods both improved and sped up all the different stages of the drug discovery processes by performing complex analyses with enormous datasets. Natural products (NPs) have been used for treating diseases and infections for thousands of years and represent a valuable resource for drug discovery when combined with the current computation advancements. Here, a dataset of 406,747 unique NPs was screened against the SARS-CoV-2 main protease (M^pro) crystal structure (6lu7) using a combination of ligand- and structural-based virtual screening. Based on 1) the predicted binding affinities of the NPs to the M^pro, 2) the types and number of interactions with the M^pro amino acids that are critical for its function, and 3) the desirable pharmacokinetic properties of the NPs, we identified the top 20 candidates that could potentially inhibit the M^pro protease function. A total of 7 of the 20 top candidates were subjected to in vitro protease inhibition assay and 4 of them (4/7; 57%), including two beta carbolines, one N-alkyl indole, and one Benzoic acid ester, had significant inhibitory activity against M^pro protease. These four NPs could be developed further for the treatment of COVID-19 symptoms.

Antitarget, Anti-SARS-CoV-2 Leads, Drugs, and the Drug Discovery-Genetics Alliance Perspective

The most advanced antiviral molecules addressing major SARS-CoV-2 targets (Main protease, Spike protein, and RNA polymerase), compared with proteins of other human pathogenic coronaviruses, may have a short-lasting clinical efficacy. Accumulating knowledge on the mechanisms underlying the target structural basis, its mutational progression, and the related biological significance to virus replication allows envisaging the development of better-targeted therapies in the context of COVID-19 epidemic and future coronavirus outbreaks. The identification of evolutionary patterns based solely on sequence information analysis for those targets can provide meaningful insights into the molecular basis of host-pathogen interactions and adaptation, leading to drug resistance phenomena. Herein, we will explore how the study of observed and predicted mutations may offer valuable suggestions for the application of the so-called "synthetic lethal" strategy to SARS-CoV-2 Main protease and Spike protein. The synergy between genetics evidence and drug discovery may prioritize the development of novel long-lasting antiviral agents.

The Role of ERα and ERβ in Castration-Resistant Prostate Cancer and Current Therapeutic Approaches

Castration-resistant prostate cancer, or CRPC, is an aggressive stage of prostate cancer (PCa) in which PCa cells invade nearby or other parts of the body. When a patient with PCa goes through androgen deprivation therapy (ADT) and the cancer comes back or worsens, this is called CRPC. Instead of androgen-dependent signalling, recent studies show the involvement of the estrogen pathway through the regulation of estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) in CRPC development. Reduced levels of testosterone due to ADT lead to low ERβ functionality in inhibiting the proliferation of PCa cells. Additionally, ERα, which possesses androgen independence, continues to promote the proliferation of PCa cells. The functions of ERα and ERβ in controlling PCa progression have been studied, but further research is needed to elucidate their roles in promoting CRPC. Finding new ways to treat the disease and stop it from becoming worse will require a clear understanding of the molecular processes that can lead to CRPC. The current review summarizes the underlying processes involving ERα and ERβ in developing CRPC, including castration-resistant mechanisms after ADT and available medication modification in mitigating CRPC progression, with the goal of directing future research and treatment.

Addressing the Reciprocal Crosstalk between the AR and the PI3K/AKT/mTOR Signaling Pathways for Prostate Cancer Treatment

The reduction in androgen synthesis and the blockade of the androgen receptor (AR) function by chemical castration and AR signaling inhibitors represent the main treatment lines for the initial stages of prostate cancer. Unfortunately, resistance mechanisms ultimately develop due to alterations in the AR pathway, such as gene amplification or mutations, and also the emergence of alternative pathways that render the tumor less or, more rarely, completely independent of androgen activation. An essential oncogenic axis activated in prostate cancer is the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, as evidenced by the frequent alterations of the negative regulator phosphatase and tensin homolog (PTEN) and by the activating mutations in PI3K subunits. Additionally, crosstalk and reciprocal feedback loops between androgen signaling and the PI3K/AKT/mTOR signaling cascade that activate pro-survival signals and play an essential role in disease recurrence and progression have been evidenced. Inhibitors addressing different players of the PI3K/AKT/mTOR pathway have been evaluated in the clinic. Only a limited benefit has been reported in prostate cancer up to now due to the associated side effects, so novel combination approaches and biomarkers predictive of patient response are urgently needed. Here, we reviewed recent data on the crosstalk between AR signaling and the PI3K/AKT/mTOR pathway, the selective inhibitors identified, and the most advanced clinical studies, with a focus on combination treatments. A deeper understanding of the complex molecular mechanisms involved in disease progression and treatment resistance is essential to further guide therapeutic approaches with improved outcomes.

Metastatic castrate-resistant prostate cancer: a new horizon beyond the androgen receptors

PURPOSE OF REVIEW

Systemic chemotherapy and second-generation androgen receptor-axis targeted therapies have been in the forefront of management for metastatic castrate-resistant prostate cancer (mCRPC) patients with low or high symptom burden. However, in the recent past, due to improvement in molecular characterization, management of mCRPC has witnessed long strides of advancement. We aim to review the novel nonhormonal and nonchemotherapeutic treatment options.

RECENT FINDINGS

Poly (ADP-ribose) polymerase inhibitors (PARPis) such as olaparib and rucaparib have been recently approved by the US FDA for use in mCRPC with germline or somatic mutations in homologous recombination repair. The combination of PARPi with androgen receptor axis-targeted agents (ARAT) or dual ARAT-based therapy has shown superior radiographic progression-free survival as a first-line treatment. A combination of AKT inhibitor ipatasertib and abiraterone has shown improvement in radiographic progression-free survival as a first-line treatment. Prostate-specific membrane antigen (PSMA)-targeted radiopharmaceutical like 177Lu-PSMA-617, a beta particle emitter has demonstrated improvement in overall survival in mCRPC patients pretreated with ARAT or taxanes. Although immune checkpoint inhibitors are being tested in mCRPC, there is no robust evidence to support this premise.

SUMMARY

These new agents have widened the treatment options for mCRPC patients. Overall treatment should be focused on improving survival while limiting the deterrent effect on the quality of life.

Novel therapeutic approaches in GEP-NETs based on genetic and epigenetic alterations

Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are heterogeneous malignancies with distinct prognosis based on primary tumor localization, grade, stage and functionality. Surgery remains the only curative option in localized tumors, but systemic therapy is the mainstay of treatment for patients with advanced disease. For decades, the therapeutic landscape of GEP-NETs was limited to chemotherapy regimens with low response rates. The arrival of novel agents such as somatostatin analogues, peptide receptor radionuclide therapy, tyrosine kinase inhibitors or mTOR-targeted drugs, has changed the therapeutic paradigm of GEP-NETs. However, the efficacy of these agents is limited in time and there is scarce knowledge of optimal treatment sequencing. In recent years, massive parallel sequencing techniques have started to unravel the genomic intricacies of these tumors, allowing us to better understand the mechanisms of resistance to current treatments and to develop new targeted agents that will hopefully start an era for personalized treatment in NETs. In this review we aim to summarize the most relevant genomic aberrations and signaling pathways underlying GEP-NET tumorigenesis and potential therapeutic strategies derived from them.

Resistance to prostate cancer treatments

A review of the current treatment options for prostate cancer and the formation of resistance to these regimens has been compiled including primary, acquired, and cross-resistance. The diversification of the pathways involved and the escape routes the tumor is utilizing have been addressed. Whereas early stages of tumor can be cured, there is no treatment available after a point of no return has been reached, leaving palliative treatment as the only option. The major reasons for this outcome are the heterogeneity of tumors, both inter- and intra-individually and the nearly endless number of escape routes, which the tumor can select to overcome the effects of treatment. This means that more focus should be applied to the individualization of both diagnosis and therapy of prostate cancer. In addition to current treatment options, novel drugs and ongoing clinical trials have been addressed in this review.

PTEN-PI3K pathway alterations in advanced prostate cancer and clinical implications

BACKGROUND

Despite significant advances in molecular characterization and therapeutic targeting of advanced prostate cancer, it remains the second most common cause of cancer death in men in the United States. The PI3K (Phosphatidylinositol 3-kinase)/AKT (AKT serine/threonine kinase)/mTOR (mammalian target of rapamycin) signaling pathway is commonly altered in prostate cancer, most frequently through loss of the PTEN (Phosphatase and Tensin Homolog) tumor suppressor, and is critical for cancer cell proliferation, migration, and survival.

METHODS

This study summarizes signaling through the PTEN/PI3K pathway, alterations in pathway components commonly seen in advanced prostate cancer, and results of clinical trials of pathway inhibitors reported to date with a focus on more recently reported studies. It also reviews rationale for combination approaches currently under study, including with taxanes, immune checkpoint inhibitors and poly (ADP-ribose) polymerase inhibitors, and discusses future directions in biomarker testing and therapeutic targeting of this pathway.

RESULTS

Clinical trials studying pharmacologic inhibitors of PI3K, AKT or mTOR kinases have demonstrated modest activity of specific agents, with several trials of pathway inhibitors currently in progress. A key challenge is the importance of PI3K/AKT/mTOR signaling in noncancerous tissues, leading to predictable but often severe toxicities at therapeutic doses.

RESULTS

Further advances in selective pharmacologic inhibition of the PI3K/AKT/mTOR pathway in tumors, development of rational combinations, and appropriate biomarker selection to identify the appropriate tumor- and patient-specific vulnerabilities will be required to optimize clinical benefit from therapeutic targeting of this pathway.

Advances in the Current Understanding of the Mechanisms Governing the Acquisition of Castration-Resistant Prostate Cancer

Despite aggressive treatment and androgen-deprivation therapy, most prostate cancer patients ultimately develop castration-resistant prostate cancer (CRPC), which is associated with high mortality rates. However, the mechanisms governing the development of CRPC are poorly understood, and androgen receptor (AR) signaling has been shown to be important in CRPC through AR gene mutations, gene overexpression, co-regulatory factors, AR shear variants, and androgen resynthesis. A growing number of non-AR pathways have also been shown to influence the CRPC progression, including the Wnt and Hh pathways. Moreover, non-coding RNAs have been identified as important regulators of the CRPC pathogenesis. The present review provides an overview of the relevant literature pertaining to the mechanisms governing the molecular acquisition of castration resistance in prostate cancer, providing a foundation for future, targeted therapeutic efforts.

Activation of CD44/PAK1/AKT signaling promotes resistance to FGFR1 inhibition in squamous-cell lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Fibroblast growth factor receptor 1 (FGFR1) gene amplification is one of the most prominent and potentially targetable genetic alterations in squamous-cell lung cancer (SQCLC). Highly selective tyrosine kinase inhibitors have been developed to target FGFR1; however, resistance mechanisms originally existing in patients or acquired during treatment have so far led to limited treatment efficiency in clinical trials. In this study we performed a wide-scale phosphoproteomic mass-spectrometry analysis to explore signaling pathways that lead to resistance toward FGFR1 inhibition in lung cancer cells that display (i) intrinsic, (ii) pharmacologically induced and (iii) mutationally induced resistance. Additionally, we correlated AKT activation to CD44 expression in 175 lung cancer patient samples. We identified a CD44/PAK1/AKT signaling axis as a commonly occurring resistance mechanism to FGFR1 inhibition in lung cancer. Co-inhibition of AKT/FGFR1, CD44/FGFR1 or PAK1/FGFR1 sensitized ‘intrinsically resistant’ and ‘induced-resistant’ lung-cancer cells synergetically to FGFR1 inhibition. Furthermore, strong CD44 expression was significantly correlated with AKT activation in SQCLC patients. Collectively, our phosphoproteomic analysis of lung-cancer cells resistant to FGFR1 inhibitor provides a large data library of resistance-associated phosphorylation patterns and leads to the proposal of a common resistance pathway comprising CD44, PAK1 and AKT activation. Examination of CD44/PAK1/AKT activation could help to predict response to FGFR1 inhibition. Moreover, combination between AKT and FGFR1 inhibitors may pave the way for an effective therapy of patients with treatment-resistant FGFR1-dependent lung cancer.

Emerging Biomarker-Guided Therapies in Prostate Cancer

Prostate cancer remains one of the leading causes of cancer death in men worldwide. In the past decade, several new treatments for advanced prostate cancer have been approved. With a wide variety of available drugs, including cytotoxic agents, androgen receptor axis-targeted therapies, and alpha-emitting radiation therapy, identifying their optimal sequencing remains a challenge. Progress in the understanding of the biology of prostate cancer has provided an opportunity for a more refined and personalized treatment selection process. With the advancement of molecular sequencing techniques, genomic precision through the identification of potential treatment targets and predictive biomarkers has been rapidly evolving. In this review, we discussed biomarker-driven treatments for advanced prostate cancer. First, we presented predictive biomarkers for established, global standard treatments for advanced diseases, such as chemotherapy and androgen receptor axis-targeted agents. We also discussed targeted agents with recent approval for special populations, such as poly ADP ribose polymerase (PARP) inhibitors in patients with metastatic castrate-resistant prostate cancer with homologous recombination repair-deficient tumors, pembrolizumab in patients with high levels of microsatellite instability or high tumor mutational burden, and prostate-specific membrane antigen (PSMA) directed radioligand theragnostic treatment for PSMA expressing tumors. Additionally, we discussed evolving treatments, such as cancer vaccines, chimeric antigen receptor T-cells (CAR-T), Bispecific T-cell engagers (BiTEs), other targeted agents such as AKT inhibitors, and various combination treatments. In summary, advances in molecular genetics have begun to propel personalized medicine forward in the management of advanced prostate cancer, allowing for a more precise, biomarker-driven treatment selection with the goal of improving overall efficacy.

Functional roles of E3 ubiquitin ligases in prostate cancer

Prostate cancer (PCa) is a malignant epithelial tumor of the prostate gland with a high male cancer incidence. Numerous studies indicate that abnormal function of ubiquitin-proteasome system (UPS) is associated with the progression and metastasis of PCa. E3 ubiquitin ligases, key components of UPS, determine the specificity of substrates, and substantial advances of E3 ubiquitin ligases have been reached recently. Herein, we introduce the structures and functions of E3 ubiquitin ligases and summarize the mechanisms of E3 ubiquitin ligases-related PCa signaling pathways. In addition, some progresses in the development of inhibitors targeting E3 ubiquitin ligases are also included.

Phase Ib/II Study of Enzalutamide with Samotolisib (LY3023414) or Placebo in Patients with Metastatic Castration-Resistant Prostate Cancer

PURPOSE

To report efficacy and safety of samotolisib (LY3023414; PI3K/mTOR dual kinase and DNA-dependent protein kinase inhibitor) plus enzalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC) following cancer progression on abiraterone.

PATIENTS AND METHODS

In this double-blind, placebo-controlled phase Ib/II study (NCT02407054), following a lead-in segment for evaluating safety and pharmacokinetics of samotolisib and enzalutamide combination, patients with advanced castration-resistant prostate cancer with progression on prior abiraterone were randomized to receive enzalutamide (160 mg daily)/samotolisib (200 mg twice daily) or placebo. Primary endpoint was progression-free survival (PFS) assessed by Prostate Cancer Clinical Trials Working Group criteria (PCWG2). Secondary and exploratory endpoints included radiographic PFS (rPFS) and biomarkers, respectively. Log-rank tests assessed treatment group differences.

RESULTS

Overall, 13 and 129 patients were enrolled in phase Ib and II, respectively. Dose-limiting toxicity was not reported in patients during phase Ib and mean samotolisib exposures remained in the targeted range despite a 35% decrease when administered with enzalutamide. In phase II, median PCWG2-PFS and rPFS was significantly longer in the samotolisib/enzalutamide versus placebo/enzalutamide arm (3.8 vs. 2.8 months; P = 0.003 and 10.2 vs. 5.5 months; P = 0.03), respectively. Patients without androgen receptor splice variant 7 showed a significant and clinically meaningful rPFS benefit in the samotolisib/enzalutamide versus placebo/enzalutamide arm (13.2 months vs. 5.3 months; P = 0.03).

CONCLUSIONS

Samotolisib/enzalutamide has tolerable side effects and significantly improved PFS in patients with mCRPC with cancer progression on abiraterone, and this may be enriched in patients with PTEN intact and no androgen receptor splice variant 7.

HER2 Mediates PSMA/mGluR1-Driven Resistance to the DS-7423 Dual PI3K/mTOR Inhibitor in PTEN Wild-type Prostate Cancer Models

Prostate cancer remains a major cause of male mortality. Genetic alteration of the PI3K/AKT/mTOR pathway is one of the key events in tumor development and progression in prostate cancer, with inactivation of the PTEN tumor suppressor being very common in this cancer type. Extensive evaluation has been performed on the therapeutic potential of PI3K/AKT/mTOR inhibitors and the resistance mechanisms arising in patients with PTEN-mutant background. However, in patients with a PTEN wild-type phenotype, PI3K/AKT/mTOR inhibitors have not demonstrated efficacy, and this remains an area of clinical unmet need. In this study, we have investigated the response of PTEN wild-type prostate cancer cell lines to the dual PI3K/mTOR inhibitor DS-7423 alone or in combination with HER2 inhibitors or mGluR1 inhibitors. Upon treatment with the dual PI3K/mTOR inhibitor DS-7423, PTEN wild-type prostate cancer CWR22/22RV1 cells upregulate expression of the proteins PSMA, mGluR1, and the tyrosine kinase receptor HER2, while PTEN-mutant LNCaP cells upregulate androgen receptor and HER3. PSMA, mGluR1, and HER2 exert control over one another in a positive feedback loop that allows cells to overcome treatment with DS-7423. Concomitant targeting of PI3K/mTOR with either HER2 or mGluR1 inhibitors results in decreased cell survival and tumor growth in xenograft studies. Our results suggest a novel therapeutic possibility for patients with PTEN wild-type PI3K/AKT-mutant prostate cancer based in the combination of PI3K/mTOR blockade with HER2 or mGluR1 inhibitors.

Telmisartan anti‐cancer activities mechanism through targeting N‐cadherin by mimicking ADH‐1 function

This study aimed to investigate if Telmisartan as a novel N‐cadherin antagonist, can overcome cell migration of cancer cells. We investigated the mechanism and influence of Docetaxel and Telmisartan (as an analogous to ADH‐1, which is a well‐known N‐cadherin antagonist) on cancer cells. The effect of ADH‐1 and Telmisartan on cell attachment in PC3, DU145, MDA‐MB‐468 cell lines using recombinant human N‐cadherin was studied. Cell viability assay was performed to examine the anti‐proliferative effects of Telmisartan, ADH‐1 and Docetaxel. Migration was examined via wound healing assay, and apoptosis was determined by flow cytometry. The expression of AKT‐1 as a downstream gene of N‐cadherin signalling pathway was assayed by real‐time PCR. Treatment of PC3, MDA‐MB‐468 and DU145 cells with Telmisartan (0.1 µM) and ADH‐1 (40 µM) resulted in 50%, 58% and approximately 20% reduction in cell attachment to N‐cadherin coated plate respectively. It shows reduction of cell attachment in PC3 and MDA‐MB‐468 cell lines appeared to be more sensitive than that of DU145 cells to the Telmisartan and ADH‐1 treatments. Telmisartan (0.1 µM) and Docetaxel (0.01 nM) significantly reduced cell migration in PC3 and MDA‐MB‐468 cell lines compared with the control group. Using Real‐time PCR, we found that Telmisartan, Docetaxel and ADH‐1 had significant influence on the AKT‐1 mRNA level. The results of the current study for the first time suggest that, Telmisartan, exerts anti‐proliferation and anti‐migration effects by targeting antagonistically N‐cadherin. Also, these data suggest that Telmisartan as a less expensive alternative to ADH‐1 could potentiate Docetaxel anticancer effects.

Choosing Kinase Inhibitors for Androgen Deprivation Therapy-Resistant Prostate Cancer

Androgen deprivation therapy (ADT) is a systemic therapy for advanced prostate cancer (PCa). Although most patients initially respond to ADT, almost all cancers eventually develop castration resistance. Castration-resistant PCa (CRPC) is associated with a very poor prognosis, and the treatment of which is a serious clinical challenge. Accumulating evidence suggests that abnormal expression and activation of various kinases are associated with the emergence and maintenance of CRPC. Many efforts have been made to develop small molecule inhibitors to target the key kinases in CRPC. These inhibitors are designed to suppress the kinase activity or interrupt kinase-mediated signal pathways that are associated with PCa androgen-independent (AI) growth and CRPC development. In this review, we briefly summarize the roles of the kinases that are abnormally expressed and/or activated in CRPC and the recent advances in the development of small molecule inhibitors that target kinases for the treatment of CRPC.

First successful case of platinum-based chemotherapy for neuroendocrine prostate cancer with BRCA2 and PTEN alterations

INTRODUCTION

Deoxyribonucleic acid repair gene mutations are now being studied in a variety of solid tumors, with the hope of predicting prognosis, pathogenesis, and treatment outcomes.

CASE PRESENTATION

We report the case of a Japanese patient with advanced castration-resistant prostate cancer who exhibited a prominent response to platinum therapy and had coexisting BRCA2 and PTEN mutations according to retrospective multigene panel analysis.

CONCLUSION

Through a review of clinical outcomes and genetic/pathologic profiling, the presented case provides insights into future management strategies based on the tumor genetic status.

Overview of the Development and Use of Akt Inhibitors in Prostate Cancer

Deregulation of the PI3K-Akt-mTOR pathway plays a critical role in the development and progression of many cancers. In prostate cancer, evidence suggests that it is mainly driven by PTEN loss of function. For many years, the development of selective Akt inhibitors has been challenging. In recent phase II and III clinical trials, Ipatasertib and Capivasertib associated with androgen deprivation therapies showed promising outcomes in patients with metastatic castration-resistant prostate cancer and PTEN-loss. Ongoing trials are currently assessing several Akt inhibitors in prostate cancer with different combinations, at different stages of the disease.

An Insight on Novel Molecular Pathways in Metastatic Prostate Cancer: A Focus on DDR, MSI and AKT

Prostate cancer is still one of the main causes of cancer-related death in the male population, regardless of the advancements in the treatment scenario. The genetic knowledge on prostate cancer is widely increasing, allowing researchers to identify novel promising molecular targets and treatment approaches. Genomic profiling has evidenced that DNA damage repair genes’ alterations are quite frequent in metastatic, castration resistant prostate cancer and specific therapies can interfere with this pathway, showing promising activity in this setting. Microsatellite instability is gaining attention as it seems to represent a predictive factor of the response to immunotherapy. Furthermore, the PTEN-PI3K-AKT pathway is another possible treatment target being investigated. In this review, we explore the current knowledge on these frequent genomic alterations of metastatic prostate cancer, their possible therapeutic repercussions and the promising future treatments under evaluation.

Clinical Development of AKT Inhibitors and Associated Predictive Biomarkers to Guide Patient Treatment in Cancer Medicine

The serine/threonine kinase AKT is a critical effector of the phosphoinositide 3-kinase (PI3K) signaling cascade and has a pivotal role in cell growth, proliferation, survival, and metabolism. AKT is one of the most commonly activated pathways in human cancer and dysregulation of AKT-dependent pathways is associated with the development and maintenance of a range of solid tumors. There are multiple small-molecule inhibitors targeting different components of the PI3K/AKT pathway currently at various stages of clinical development, in addition to new combination strategies aiming to boost the therapeutic efficacy of these drugs. Correlative and translational studies have been undertaken in the context of clinical trials investigating AKT inhibitors, however the identification of predictive biomarkers of response and resistance to AKT inhibition remains an unmet need. In this review, we discuss the biological function and activation of AKT, discuss its contribution to tumor development and progression, and review the efficacy and toxicity data from clinical trials, including both AKT inhibitor monotherapy and combination strategies with other agents. We also discuss the promise and challenges associated with the development of AKT inhibitors and associated predictive biomarkers of response and resistance.

SPP1 Promotes Enzalutamide Resistance and Epithelial-Mesenchymal-Transition Activation in Castration-Resistant Prostate Cancer via PI3K/AKT and ERK1/2 Pathways

The bottleneck arising from castration-resistant prostate cancer (CRPC) treatment is its high metastasis potential and antiandrogen drug resistance, which severely affects survival time of prostate cancer (PCa) patients. Secreted phosphoprotein 1 (SPP1) is a cardinal mediator of tumor-associated inflammation and facilitates metastasis. In our previous study, we firstly revealed SPP1 was a potential hub signature for predicting metastatic CRPC (mCRPC) development. Herein, we integrated multiple databases to explore the association of SPP1 expression with prognosis, survival, and metastatic levels in CRPC progression and investigated SPP1 expression in PCa tissues and cell lines. Next, PCa cell lines with overexpression or depletion of SPP1 were established to study the effect of SPP1 on enzalutamide sensitivity and adhesion and migration of prostate cancer cell lines and further explore the underlying regulatory mechanisms. Bioinformatics analysis, polymerase chain reaction (PCR), immunohistochemical staining, and western blot results suggested SPP1 upregulation had strong relationship with the malignant progression of CRPC and enzalutamide resistance. SPP1 knockdown enhanced enzalutamide sensitivity and repressed invasion and migration of prostate cancer cells. Importantly, upregulating SPP1 promoted, while silencing SPP1 attenuated epithelial-mesenchymal-transition (EMT). Our results further demonstrated that SPP1 overexpression maintains the activation of PI3K/AKT and ERK1/2 signaling pathways. Overall, our findings unraveled the functional role and clinical significance of SPP1 in PCa progression and help to discover new potential targets against mCRPC.

Role of PI3K-AKT-mTOR Pathway as a Pro-Survival Signaling and Resistance-Mediating Mechanism to Therapy of Prostate Cancer

Androgen deprivation therapy (ADT) and androgen receptor (AR)-targeted therapy are the gold standard options for treating prostate cancer (PCa). These are initially effective, as localized and the early stage of metastatic disease are androgen- and castration-sensitive. The tumor strongly relies on systemic/circulating androgens for activating AR signaling to stimulate growth and progression. However, after a certain point, the tumor will eventually develop a resistant stage, where ADT and AR antagonists are no longer effective. Mechanistically, it seems that the tumor becomes more aggressive through adaptive responses, relies more on alternative activated pathways, and is less dependent on AR signaling. This includes hyperactivation of PI3K-AKT-mTOR pathway, which is a central signal that regulates cell pro-survival/anti-apoptotic pathways, thus, compensating the blockade of AR signaling. The PI3K-AKT-mTOR pathway is well-documented for its crosstalk between genomic and non-genomic AR signaling, as well as other signaling cascades. Such a reciprocal feedback loop makes it more complicated to target individual factor/signaling for treating PCa. Here, we highlight the role of PI3K-AKT-mTOR signaling as a resistance mechanism for PCa therapy and illustrate the transition of prostate tumor from AR signaling-dependent to PI3K-AKT-mTOR pathway-dependent. Moreover, therapeutic strategies with inhibitors targeting the PI3K-AKT-mTOR signal used in clinic and ongoing clinical trials are discussed.

Molecular Characterization of Prostate Cancers in the Precision Medicine Era

Prostate cancer (PCa) therapy has been recently revolutionized by the approval of new therapeutic agents in the metastatic setting. However, the optimal therapeutic strategy in such patients should be individualized in the light of prognostic and predictive molecular factors, which have been recently studied: androgen receptor (AR) alterations, PTEN-PI3K-AKT pathway deregulation, homologous recombination deficiency (HRD), mismatch repair deficiency (MMRd), and tumor microenvironment (TME) modifications. In this review, we highlighted the clinical impact of prognostic and predictive molecular factors in PCa patients' outcomes, identifying biologically distinct subtypes. We further analyzed the relevant methods to detect these factors, both on tissue, i.e., immunohistochemistry (IHC) and molecular tests, and blood, i.e., analysis of circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA). Moreover, we discussed the main pros and cons of such techniques, depicting their present and future roles in PCa management, throughout the precision medicine era.

The Akt-mTOR network at the interface of hematopoietic stem cell homeostasis

Hematopoietic stem cells (HSCs) are immature blood cells that exhibit multilineage differentiation capacity. Homeostasis is critical for HSC potential and lifelong hematopoiesis, and HSC homeostasis is tightly governed by both intrinsic molecular networks and microenvironmental signals. The evolutionarily conserved serine/threonine protein kinase B (PKB, also referred to as Akt)-mammalian target of rapamycin (mTOR) pathway is universal to nearly all multicellular organisms and plays an integral role in most cellular processes. Emerging evidence has revealed a central role of the Akt-mTOR network in HSC homeostasis, because it responds to multiple intracellular and extracellular signals and regulates various downstream targets, eventually affecting several cellular processes, including the cell cycle, mitochondrial metabolism, and protein synthesis. Dysregulated Akt-mTOR signaling greatly affects HSC self-renewal, maintenance, differentiation, survival, autophagy, and aging, as well as transformation of HSCs to leukemia stem cells. Here, we review recent works and provide an advanced understanding of how the Akt-mTOR network regulates HSC homeostasis, thus offering insights into future clinical applications.

Discovery of N-((3S,4S)-4-(3,4-Difluorophenyl)piperidin-3-yl)-2-fluoro-4-(1-methyl-1H-pyrazol-5-yl)benzamide (Hu7691), a Potent and Selective Akt Inhibitor That Enables Decrease of Cutaneous Toxicity

Rash is one of the primary dose-limiting toxicities of Akt (protein kinase B) inhibitors in clinical trials. Here, we demonstrate the inhibition of Akt2 isozyme may be a driver for keratinocyte apoptosis, which promotes us to search for new selective Akt inhibitors with an improved cutaneous safety property. According to our previous research, compound 2 is selected for further optimization for overcoming the disadvantages of compound 1, including high Akt2 inhibition and high toxicity against HaCaT keratinocytes. The dihedral angle-based design and molecular dynamics simulation lead to the identification of Hu7691 (B5) that achieves a 24-fold selectivity between Akt1 and Akt2. Hu7691 exhibits low activity in inducing HaCaT apoptosis, promising kinase selectivity, and excellent anticancer cell proliferation potencies. Based on the superior results of safety property, pharmacokinetic profile, and in vivo efficacy, the National Medical Products Administration (NMPA) approved the investigational new drug (IND) application of Hu7691.

Advances in autophagy as a target in the treatment of tumours

Autophagy is a multi-step lysosomal degradation process, which regulates energy and material metabolism and has been used to maintain homeostasis. Autophagy has been shown to be involved in the regulation of health and disease. But at present, there is no consensus on the relationship between autophagy and tumour, and we consider that it plays a dual role in the occurrence and development of tumour. That is to say, under certain conditions, it can inhibit the occurrence of tumour, but it can also promote the process of tumour. Therefore, autophagy could be used as a target for tumour treatment. The regulation of autophagy plays a synergistic role in the radiotherapy, chemotherapy, phototherapy and immunotherapy of tumour, and nano drug delivery system provides a promising strategy for improving the efficacy of autophagy regulation. This review summarised the progress in the regulatory pathways and factors of autophagy as well as nanoformulations as carriers for the delivery of autophagy modulators.

Targeting the PI3K-AKT-mTOR Pathway in Castration Resistant Prostate Cancer: A Review Article

BACKGROUND

Prostate cancer is one of leading causes of cancer death among men worldwide. Androgen deprivation therapy is a central part of the prostate cancer treatment algorithm, however, resistance to androgen deprivation commonly leads to disease progression. Mutations in the phosphoinositide-3-kinase pathway (PI3K) have been implicated in cancer progression and the development of castration-resistance. Thus, inhibitors of this pathway and its downstream signaling partners have been studied as potential therapeutic agents to treat metastatic castration resistant prostate cancer (mCRPC).  In this article, we review recent clinical results for novel targeted therapies against the PI3K-AKT-mTOR pathway.

MATERIALS AND METHODS

Trials included in this systemic review were identified through conference abstracts, citations in review articles, PubMed, and ClinicalTrials.gov. Trial eligibility was independent of clinical setting or sample size.

RESULTS

A total of 13 prospective clinical trials between 2012 and 2020 were reviewed: Two trials for pan-PI3K inhibitors, 2 trials for selective PI3K inhibitors, 4 trials for AKT inhibitors, 5 trials for mTOR inhibitors, and 1 for a combined PI3K and mTOR inhibitor. All studies were phase I or II studies with primary outcomes of either safety and tolerability or efficacy.

CONCLUSION

Overall, pan-PI3K inhibitors and selective-PI3K inhibitors have not demonstrated clinical efficacy and may have significant adverse effects. AKT inhibitors may have significant adverse effects, but showed some evidence of improved survival. mTORC1 inhibitors show modest efficacy and significant adverse effects.

A Phase I, Open-Label, Dose-Finding Study of GSK2636771, a PI3Kβ inhibitor, Administered with Enzalutamide in Patients with Metastatic Castration-Resistant Prostate Cancer

PURPOSE

In patients with metastatic castration-resistant prostate cancer (mCRPC), resistance to androgen receptor (AR) targeted therapies, such as enzalutamide, remains an issue. Inactivation of inhibitory phosphatase and tensin homolog (PTEN) activates phosphoinositide 3-kinase (PI3K)/AKT signaling and contributes to resistance to androgen-deprivation therapy and poor outcomes. Therefore, dual targeting of AR and PI3K/AKT pathways may limit tumor growth and reverse resistance.

PATIENTS AND METHODS

In this Phase I study (NCT02215096), patients with PTEN-deficient mCRPC, who progressed on prior enzalutamide, received once-daily enzalutamide 160 mg plus PI3Kβ inhibitor GSK2636771 at 300 mg initial dose, with escalation or de-escalation in 100 mg increments, followed by dose expansion. Primary objectives were to evaluate safety/tolerability, determine the recommended Phase II dose (RP2D), and assess the 12-week non-progressive disease (PD) rate.

RESULTS

Overall, 37 patients were enrolled; 36 received {greater than or equal to}1 dose of GSK2636771 (200 mg: n=22, 300 mg: n=12; 400 mg: n=2) plus 160 mg enzalutamide. Dose-limiting toxicities occurred in 5 patients (200 mg: n=1; 300 mg: n=2, 400 mg: n=2). No new or unexpected adverse events nor evidence of drug-drug interaction were observed. At the recommended dose of GSK2636771 (200 mg) plus enzalutamide, the 12-week non-PD rate was 50% (95% CI: 28.2-71.8%, n=22); 1 (3%) patient achieved a radiographic partial response lasting 36 weeks. 4/34 (12%) patients had prostate-specific antigen reduction of {greater than or equal to}50%.

CONCLUSIONS

Although there was acceptable safety and tolerability with GSK2636771 plus enzalutamide in patients with PTEN-deficient mCRPC after failing enzalutamide, limited antitumor activity was observed.

Targeting the PI3K/AKT/mTOR Signaling Pathway in Lung Cancer: An Update Regarding Potential Drugs and Natural Products

Lung cancer is one of the most common cancers and has a high mortality rate. Due to its high incidence, the clinical management of the disease remains a major challenge. Several reports have documented a relationship between the phosphatidylinositol-3-kinase (PI3K)/ protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway and lung cancer. The recognition of this pathway as a notable therapeutic target in lung cancer is mainly due to its central involvement in the initiation and progression of the disease. Interest in using natural and synthetic medications to target these signaling pathways has increased in recent years, with promising results in vitro, in vivo, and in clinical trials. In this review, we focus on the current understanding of PI3K/AKT/mTOR signaling in tumor development. In addition to the signaling pathway, we highlighted the therapeutic potential of recently developed PI3K/AKT/mTOR inhibitors based on preclinical and clinical trials.

Attacking the PI3K/Akt/mTOR signaling pathway for targeted therapeutic treatment in human cancer

Cancer is the second leading cause of human death globally. PI3K/Akt/mTOR signaling is one of the most frequently dysregulated signaling pathways observed in cancer patients that plays crucial roles in promoting tumor initiation, progression and therapy responses. This is largely due to that PI3K/Akt/mTOR signaling is indispensable for many cellular biological processes, including cell growth, metastasis, survival, metabolism, and others. As such, small molecule inhibitors targeting major kinase components of the PI3K/Akt/mTOR signaling pathway have drawn extensive attention and been developed and evaluated in preclinical models and clinical trials. Targeting a single kinase component within this signaling usually causes growth arrest rather than apoptosis associated with toxicity-induced adverse effects in patients. Combination therapies including PI3K/Akt/mTOR inhibitors show improved patient response and clinical outcome, albeit developed resistance has been reported. In this review, we focus on revealing the mechanisms leading to the hyperactivation of PI3K/Akt/mTOR signaling in cancer and summarizing efforts for developing PI3K/Akt/mTOR inhibitors as either mono-therapy or combination therapy in different cancer settings. We hope that this review will facilitate further understanding of the regulatory mechanisms governing dysregulation of PI3K/Akt/mTOR oncogenic signaling in cancer and provide insights into possible future directions for targeted therapeutic regimen for cancer treatment, by developing new agents, drug delivery systems, or combination regimen to target the PI3K/Akt/mTOR signaling pathway. This information will also provide effective patient stratification strategy to improve the patient response and clinical outcome for cancer patients with deregulated PI3K/Akt/mTOR signaling.

Capivasertib restricts SARS-CoV-2 cellular entry: a potential clinical application for COVID-19

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has led to more than 150 million infections and about 3.1 million deaths up to date. Currently, drugs screened are urgently aiming to block the infection of SARS-CoV-2. Here, we explored the interaction networks of kinase and COVID-19 crosstalk, and identified phosphoinositide 3-kinase (PI3K)/AKT pathway as the most important kinase signal pathway involving COVID-19. Further, we found a PI3K/AKT signal pathway inhibitor capivasertib restricted the entry of SARS-CoV-2 into cells under non-cytotoxic concentrations. Lastly, the signal axis PI3K/AKT/FYVE finger-containing phosphoinositide kinase (PIKfyve)/PtdIns(3,5)P2 was revealed to play a key role during the cellular entry of viruses including SARS-CoV-2, possibly providing potential antiviral targets. Altogether, our study suggests that the PI3K/AKT kinase inhibitor drugs may be a promising anti-SARS-CoV-2 strategy for clinical application, especially for managing cancer patients with COVID-19 in the pandemic era.

Beyond the Androgen Receptor: The Sequence, the Mutants, and New Avengers in the Treatment of Castrate-Resistant Metastatic Prostate Cancer

Targeting the androgen receptor by depriving testosterone with gonadotropin-releasing hormone agonists or antagonists, or surgical castration, has been the backbone of metastatic prostate cancer treatment. Although most prostate cancers initially respond to androgen deprivation, metastatic castration-resistant prostate cancer evolves into a heterogeneous disease with diverse drivers of progression and mechanisms of therapeutic resistance. Development of castrate resistance phenotype is associated with lethality despite the recent noteworthy strides gained via increase in therapeutic options. Identification of novel therapeutics to further improve survival and achieve durable responses in metastatic castration-resistant prostate cancer is a clinical necessity. In this review, we outline the existing avengers for treatment of metastatic castration-resistant prostate cancer by clinical presentation, placing into context the clinical state of the patient, such as burden of disease and symptoms. Doing so might aid in the ability to optimize the sequence of agents and allow for maximal exposure to life-prolonging therapeutics. Realizing the limitations of the androgen signaling inhibition, we explore the androgen-indifferent prostate cancer: the mutants. Classically, these subtypes have been associated with variant histology, but androgen-indifferent prostate cancer features are now frequently observed in association with heterogeneous morphologies, including double-negative prostate cancers, lacking both androgen receptor and neuroendocrine features, or clinicopathologic criteria, such as the aggressive variant prostate cancer criteria. The framework of new avengers against metastatic castration-resistant prostate cancer based on mechanism, including DNA repair, immune checkpoint inhibition, PTEN/PI3K/AKT pathway, prostate-specific membrane antigen targets, bispecific T-cell engagers, and radionuclide therapies, is summarized in this review.

Assessment of PI3K/mTOR/AKT Pathway Elements to Serve as Biomarkers and Therapeutic Targets in Penile Cancer

The PI3K/mTOR/AKT pathway might represent an intriguing option for treatment of penile cancer (PeCa). We aimed to assess whether members of this pathway might serve as biomarkers and targets for systemic therapy. Tissue of primary cancer from treatment-naïve PeCa patients was used for tissue microarray analysis. Immunohistochemical staining was performed with antibodies against AKT, pAKT, mTOR, pmTOR, pS6, pPRAS, p4EBP1, S6K1 and pp70S6K. Protein expression was correlated with clinicopathological characteristics as well as overall survival (OS), disease-specific survival (DSS), recurrence-free survival (RFS) and metastasis-free survival (MFS). AKT inhibition was tested in two primarily established, treatment-naïve PeCa cell lines by treatment with capivasertib and analysis of cell viability and chemotaxis. A total of 76 patients surgically treated for invasive PeCa were included. Higher expression of AKT was significantly more prevalent in high-grade tumors and predictive of DSS and OS in the Kaplan-Meier analysis, and an independent predictor of worse OS and DSS in the multivariate regression analysis. Treatment with pan-AKT inhibitor capivasertib in PeCa cell lines induced a significant downregulation of both total AKT and pAKT as well as decreased cell viability and chemotaxis. Selected protein candidates of the mTOR/AKT signaling pathway demonstrate association with histological and survival parameters of PeCa patients, whereas AKT appears to be the most promising one.

Pinin promotes tumor progression via activating CREB through PI3K/AKT and ERK/MAPK pathway in prostate cancer

Pinin (PNN), a desmosome associated protein, was demonstrated to be over-expressed and act as a tumor-promoting factor in ovarian cancer, hepatocellular carcinoma and colorectal cancer. However, the precise role of PNN in prostate cancer is still unknown. In the study, we reported that PNN was upregulated in prostate cancer tissues and PNN expression was positively associated with Gleason score, tumor stage and tumor metastasis. PNN promoted cell growth and tumorigenicity in vitro and in vivo, and modulated cell growth through driving G1/S transition via CDK6, CDK2, and Cyclin D1 in prostate cancer cells. Furthermore, PNN accelerated cell invasion, migration and EMT processes of prostate cancer cells, accompanied with the up-regulation of MMP-2, MMP-9, N-cadherin, Vimentin and down-regulation of E-cadherin. Mechanism study demonstrated that the proliferation- and motility-promoting effects of PNN on prostate cancer cells dependent on the activation of CREB, which was reversed by CREB inhibition. More important, PNN activated CREB via PI3K/AKT and ERK/MAPK pathway. Collectively, these findings indicated that PNN plays important roles in prostate cancer tumorigenesis and progression and it is a potential therapeutic target for prostate cancer treatment.