Emerging cell cycle inhibitors for treating metastatic castration-resistant prostate cancer

Y-box binding protein 1/cyclin A1 axis specifically promotes cell cycle progression at G2/M phase in ovarian cancer

Y-box binding protein 1 (YBX1) promotes oncogenic transformation and tumor growth. YBX1 plays a role in regulation of cell cycle promotion via upregulation of cell cycle-related genes. In ovarian cancer, YBX1 also promotes tumor growth, but the mechanisms of YBX1 in cell growth and cell cycle in ovarian cancer remain not to be fully understood. Here, we investigated whether YBX1-dependent cancer cell proliferation was specifically associated with expression of cell cycle related genes in ovarian cancer. Protein and mRNA expression levels of YBX1 and cell cycle-related genes in ovarian cancer cell lines and tissues were determined by western blot analysis, immunohistochemical analysis and reverse transcription-quantitative PCR. Cell cycle analysis was performed by flow cytometry. Luciferase assay and Chromatin immunoprecipitation assay were used to investigate a transcriptional function of YBX1. YBX1 silencing induced marked growth suppression in 4 cell lines (group A), moderate suppression in 5 cell lines (group B), and no suppression in 3 cell lines (group C) among 12 ovarian cancer cell lines in culture. The YBX1 silencing induced cell cycle arrest at G2/M phase and suppressed expression of cyclin A1 gene in group A and B cell lines, but not in group C cell lines. Cyclin A1 silencing specifically suppressed cell proliferation in group A cell lines and partially in group B cell lines, but not at all in group C cell lines. YBX1 mRNA levels were significantly correlated with cyclin A1 mRNA levels in patients with high-grade serous carcinoma. Augmented YBX1 expression plays a key role in tumor growth promotion in ovarian cancer in its close association with cyclin A1.

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.

Updates on Diagnosis and Treatment of PIK3CA-Related Overgrowth Spectrum

ABSTRACT

Hyperactivation of the PI3K/AKT/mTOR signaling pathway caused by PIK3CA mutations is associated with a category of overgrowth syndromes that are defined as PIK3CA -related overgrowth spectrum (PROS). The clinical features of PROS are highly heterogeneous and usually present as vascular malformations, bone and soft tissue overgrowth, and neurological and visceral abnormalities. Detection of PIK3CA variants is necessary for diagnosis and provides the basis for targeted therapy for PROS. Drugs that inhibit the PI3K pathway offer alternatives to conventional therapies. This article reviews the current knowledge of PROS and summarizes the latest progress in precise treatment, providing new insights into future therapies and research goals.

Adapting to hormone-therapy resistance for adopting the right therapeutic strategy in advanced prostate cancer

INTRODUCTION

The androgen/androgen receptor (AR) axis represents a key driver of treatment resistance in prostate cancer (PCa) patients receiving androgen deprivation therapy (ADT) and targeted agents, and a deeper comprehension of resistance mechanisms is fundamental to adopt effective therapeutic strategies.

AREAS COVERED

We review the mechanisms of primary or secondary resistance to hormone therapy (HT) in PCa, especially focusing on available data and emerging evidence.

EXPERT OPINION

First- and second-generation HT resistance has been associated with several AR-dependent and AR-independent mechanisms, ranging from the amplification of the AR gene locus to somatic AR mutations and the intratumoral synthesis of androgens from adrenal steroids and cholesterol. As reported in the current review, the development of novel and effective treatments is needed to personalize anticancer therapies in this setting and to finally improve clinical outcomes in patients with HT resistant disease.

Compound K is a potential clinical anticancer agent in prostate cancer by arresting cell cycle

BACKGROUND

Ginsenosides, phenolic compounds, and polysaccharides are the bioactive constituents of Panax ginseng Meyer. Compound K (CK) is a secondary ginsenoside with better bioavailability. It is also a promising anticancer agent.

PURPOSE

We aimed to evaluate the effect of CK on prostate cancer (PCa) and its potential mechanisms.

STUDY DESIGN

The proliferation, migration and cell cycle of PCa cells after CK treatment were assessed in various PCa cell lines. Docetaxel was used as a positive control drug. Unlike other published studies, the potential mechanisms of CK (50 μM) were investigated by an unbiased global transcriptome sequencing in the current study.

METHODS

Key CK related genes (CRGs) with prognostic significance were identified and verified by bioinformatic methods using data from the TCGA dataset and GSE21034 dataset. The role of CDK1 in the effect of CK treatment on PCa cells was investigated by overexpression of CDK1.

RESULTS

CK inhibited the proliferation and migration of PCa cells at concentrations (less than 25 μM) without obvious cytotoxicity. Five key CRGs with prognostic significance were identified, including CCNA2, CCNB2, CCNE2, CDK1, and PKMYT1, which are involved in cell cycle pathways. CK inhibited the expression of these 5 genes and the cell cycle of PCa cells. According to the results of bioinformatic analysis, the expression of the five key CRGs was strongly associated with poor prognosis and advanced pathological stage and grade of PCa. In addition, CK could restore androgen sensitivity in castration-resistant PCa cells, probably by inhibiting the expression of CDK1. After CDK1 overexpression, the inhibition of proliferation and migration of PCa cells by CK was decreased. The inhibition on the phosphorylation of AKT by CK was also reduced.

CONCLUSION

CK can inhibit PCa cells, and the mechanisms may be associated with the inhibition of cell cycle pathways through CDK1. CK is also a potential clinical anticancer agent for treating PCa.

Factors influencing survival in metastatic castration resistant prostate cancer therapy

INTRODUCTION

The number of patients with metastatic castration resistant prostate cancer (mCRPC) is expecting to increase due to the long-life expectancy of those with advanced disease who are also more commonly diagnosed today because of stage migration. Several compounds are available for treating these patients.

AREAS COVERED

We reviewed currently available treatments for mCRPC, their mechanism of action and resistance and we explored possible predictors of treatment success useful to predict survival in mCRPC patients.

EXPERT OPINION

A combination of molecular, clinical, pathological, and imaging features is necessary to correctly estimate patients' risk of death. The combination of these biomarkers may allow clinicians to tailor treatments based on cancer history and patients' features. The search of predictive biomarkers remains an unmet medical need for most patients with mCRPC.

In Silico Studies of Piperidine Derivatives as Protein Kinase B Inhibitors through 3D-QSAR, Molecular Docking and Molecular Dynamics Simulation

Background:

Protein kinase B (Akt) is a serine/threonine-protein kinase that drives the diverse physiological process. Akt is a promising therapeutic target, which involves cancer cell growth, survival, proliferation and metabolism.

Objective:

The study aims to design highly active Akt inhibitors, and to elucidate the structural requirements for their biological activity, we analyzed the key binding features and summarized the structural determinants for their bioactivities.

Methods:

A series of piperidine derivatives have been investigated employing three-dimensional quantitative structure-activity relationship (3D-QSAR), molecular docking and molecular dynamics simulation.

Results:

The statistics of the comparative molecular field analysis (CoMFA) model (Q2=0.631, R2=0.951) and the comparative molecular similarity index analysis (CoMSIA) model (Q2=0.663, R2=0.966) indicated that our 3D-QSAR model was accurate and reliable. Besides, the stability of receptor-ligand interactions under physiological conditions was then evaluated by molecular dynamics simulation, in agreement with the molecular docking results.

Conclusion:

Our study provided valuable insights for the discovery of potent Akt inhibitors.

Unravelling the Role of Kinases That Underpin Androgen Signalling in Prostate Cancer

The androgen receptor (AR) signalling pathway is the key driver in most prostate cancers (PCa), and is underpinned by several kinases both upstream and downstream of the AR. Many popular therapies for PCa that target the AR directly, however, have been circumvented by AR mutation, such as androgen receptor variants. Some upstream kinases promote AR signalling, including those which phosphorylate the AR and others that are AR-regulated, and androgen regulated kinase that can also form feed-forward activation circuits to promotes AR function. All of these kinases represent potentially druggable targets for PCa. There has generally been a divide in reviews reporting on pathways upstream of the AR and those reporting on AR-regulated genes despite the overlap that constitutes the promotion of AR signalling and PCa progression. In this review, we aim to elucidate which kinases—both upstream and AR-regulated—may be therapeutic targets and require future investigation and ongoing trials in developing kinase inhibitors for PCa.

Cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with ralaniten analogues for the treatment of androgen receptor-positive prostate and breast cancers

Androgen receptor (AR) has essential roles in the growth of prostate cancer and some breast cancers. Inhibition of AR transcriptional activity by targeting its N-terminal domain with ralaniten or an analogue such as EPI-7170 causes accumulation of cells in the G1 phase of the cell cycle. Inhibition of cyclin-dependent kinases 4/6 with palbociclib also leads to accumulation of cells in the G1 phase. Here a combination of EPI-7170 with palbociclib attenuated the in vivo growth of human castration-resistant prostate cancer xenografts that are resistant to antiandrogens. Cell-cycle tracing experiments in cultured cells revealed that EPI-7170 targeted cells in S phase, possibly through inducing DNA damage or impairing the DNA damage response, whereas palbociclib targeted the G1-S transition to delay the cell cycle. Combination treatment prevented cells in G1 and G2/M from progressing in the cell cycle and caused a portion of cells in S phase to arrest which contributed to a two-fold increase in doubling time to >63 hours compared to 25 hours in control cells. Importantly, sequential combination treatments with palbociclib administered first then followed by EPI-7170, resulted in more cells accumulating in G1 and less cells in S phase than concomitant combination which was presumably because each inhibitor has a unique mechanism in modulating the cell cycle in cancer cells. Together these data support that the combination therapy was more effective than individual monotherapies to reduce tumor growth by targeting different phases of the cell cycle.

A Perspective on Withania somnifera Modulating Antitumor Immunity in Targeting Prostate Cancer

Medicinal plants serve as a lead source of bioactive compounds and have been an integral part of day-to-day life in treating various disease conditions since ancient times. Withaferin A (WFA), a bioactive ingredient of Withania somnifera, has been used for health and medicinal purposes for its adaptogenic, anti-inflammatory, and anticancer properties long before the published literature came into existence. Nearly 25% of pharmaceutical drugs are derived from medicinal plants, classified as dietary supplements. The bioactive compounds in these supplements may serve as chemotherapeutic substances competent to inhibit or reverse the process of carcinogenesis. The role of WFA is appreciated to polarize tumor-suppressive Th1-type immune response inducing natural killer cell activity and may provide an opportunity to manipulate the tumor microenvironment at an early stage to inhibit tumor progression. This article signifies the cumulative information about the role of WFA in modulating antitumor immunity and its potential in targeting prostate cancer.

E2F7, regulated by miR‑30c, inhibits apoptosis and promotes cell cycle of prostate cancer cells

Prostate cancer (PCa) remains a leading cause of mortality among men in the United States and Western Europe. The molecular mechanism of PCa pathogenesis has not been fully elucidated. In the present study, the expression profile of E2F transcription factor 7 (E2F7) in PCa was examined using immunohistochemistry and reverse transcription‑quantitative PCR, whilst cell cycle progression and apoptosis were determined using fluorescent cell activated sorting techniques. Cell viability was measured using Cell Counting Kit‑8 in loss‑ and gain‑of‑function studies. Dual‑luciferase reporter assay was used to verify if E2F7 was one of the potential targets of miR‑30c. The staining score of E2F7 of PCa tissues was found to be notably higher compared with that of adjacent normal tissues. Suppression of E2F7 expression in PCa cell lines led to significantly reduced proliferation rates, increased proportion of cells in the G1 phase of the cell cycle and higher apoptotic rates compared with those in negative control groups. Dual‑luciferase reporter assay revealed E2F7 to be one of the binding targets of microRNA (miR)‑30c. In addition, transfection of miR‑30c mimics into PCa cells resulted in reduced cell viability, increased proportion of cells in the G1 phase and higher apoptotic rates. By contrast, transfection with the miR‑30c inhibitor led to lower apoptosis rates of PCa cells compared with negative control groups, whilst E2F7 siRNA co‑transfection reversed stimulatory effects of miR‑30c inhibitors on cell viability. In addition, the expression of cyclin‑dependent kinase inhibitor p21 were found to be upregulated by transfection with either E2F7 siRNA or miR‑30c mimics into PCa cells. In conclusion, the present study suggested that E2F7 may be positively associated with PCa cell proliferation by inhibiting p21, whereas E2F7 is in turn under regulation by miR‑30c. These observations suggest the miR‑30c/E2F7/p21 axis to be a viable therapeutic target for PCa.

Anticancer Imidazoacridinone C-1311 is Effective in Androgen-Dependent and Androgen-Independent Prostate Cancer Cells

The androgen receptor (AR) plays a critical role in prostate cancer (PCa) development and metastasis. Thus, blocking AR activity and its downstream signaling constitutes a major strategy for PCa treatment. Here, we report on the potent anti-PCa activity of a small-molecule imidazoacridinone, C-1311. In AR-positive PCa cells, C-1311 was found to inhibit the transcriptional activity of AR, uncovering a novel mechanism that may be relevant for its anticancer effect. Mechanistically, C-1311 decreased the AR binding to the prostate-specific antigen (PSA) promoter, reduced the PSA protein level, and, as shown by transcriptome sequencing, downregulated numerous AR target genes. Importantly, AR-negative PCa cells were also sensitive to C-1311, suggesting a promising efficacy in the androgen-independent PCa sub-type. Irrespective of AR status, C-1311 induced DNA damage, arrested cell cycle progression, and induced apoptosis. RNA sequencing indicated significant differences in the transcriptional response to C-1311 between the PCa cells. Gene ontology analysis showed that in AR-dependent PCa cells, C-1311 mainly affected the DNA damage response pathways. In contrast, in AR-independent PCa cells, C-1311 targeted the cellular metabolism and inhibited the genes regulating glycolysis and gluconeogenesis. Together, these results indicate that C-1311 warrants further development for the treatment of PCa.

Hint1 Overexpression Inhibits the Cell Cycle and Induces Cell Apoptosis in Human Osteosarcoma Cells

Background

New evidence suggests that histidine triad nucleotide-binding protein 1 (Hint1) exerts a tumor suppressor effect in various human tumors, such as colorectal cancer and gastric cancer. However, it has not been reported whether Hint1 is involved in the occurrence and development of osteosarcoma (OS).

Materials and Methods

The present study investigated the role of Hint1 in human OS cells by using cell lines, including 143B, U2OS, KHOS-240S, Saos-2 and MG-63. Cell proliferation and apoptosis were detected by flow cytometry.

Results

The present result revealed that Hint1 is downregulated in these cell lines. The overexpression of Hint1 by adenovirus transfection in 143B and MG63 cell lines suppressed the proliferation and cell cycle, and increased the cell apoptosis. Mechanically, it was found that Hint1 downregulated the cyclin D1 expression via FOXO1 inhibition. Furthermore, FOXO1 overexpression in the 143B and MG63 cell lines significantly blurred the effects of Hint1 on cellular proliferation and apoptosis.

Conclusion

The present study indicates that Hint1 inhibits the development of OS by regulating FoxO1-cyclin D1, suggesting that Hint1 may be a new method for the treatment of OS.

Comprehensive Analysis of Candidate Diagnostic and Prognostic Biomarkers Associated with Lung Adenocarcinoma

Background

We aimed to screen and identify central genetic and molecular targets involved in advancement of lung adenocarcinoma (LUAD) and to perform an integrated analysis and clinical validation.

Material/Methods

The GEO2R technique was utilized to assess differentially expressed genes (DEGs) among the gene sets GSE75037, GSE85716, and GSE118370. Subsequently, gene Ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) analytical methods were executed to determine related biofunctions and signaling pathways, which were annotated with tools from the Database for Annotation, Visualization and Integrated Discovery (DAVID) resource. Then, a protein-protein interaction (PPI) network complex consisting of all detected DEGs was built with the STRING web interface. Cytohubba and MCODE plug-ins for Cytoscape software and Gene Expression Profiling Interactive Analysis (GEPIA) were employed to identify the hub genes. Finally, the mRNA expression of the identified hub genes was quantitatively validated by The Cancer Genome Atlas (TCGA) database analysis and real-time quantitative polymerase chain reaction (RT-qPCR).

Results

We screened 146 upregulated DEGs and 431 downregulated DEGs with the criteria of |logFC| >1 and P<0.05, and the GO analysis indicated that DEGs were implicated in mitotic nuclear division (biological process, BP), the nucleus (cellular component, CC), and protein binding (molecular function, MF) and were associated with multiple KEGG pathways, such as the p53 signaling pathway in cancer. Then, the top 8 genes that predicted significantly different outcomes in LUAD patients were filtered from the DEGs and selected as hub genes. The TCGA database analysis and RT-qPCR results demonstrated that these genes were differentially expressed with the same trends in LUAD tissues compared with normal tissues.

Conclusions

Overall, we propose that 8 genes (PECAM1, CDK1, MKI67, SPP1, TOP2A, CHEK1, CCNB1, and RRM2) might be novel hub genes strongly associated with the progression and prognosis of LUAD.

Polyphenolic Compounds from Lespedeza Bicolor Root Bark Inhibit Progression of Human Prostate Cancer Cells via Induction of Apoptosis and Cell Cycle Arrest

From a root bark of Lespedeza bicolor Turch we isolated two new (7 and 8) and six previously known compounds (1–6) belonging to the group of prenylated polyphenols. Their structures were elucidated using mass spectrometry, nuclear magnetic resonance and circular dichroism spectroscopy. These natural compounds selectively inhibited human drug-resistant prostate cancer in vitro. Prenylated pterocarpans 1–3 prevented the cell cycle progression of human cancer cells in S-phase. This was accompanied by a reduced expression of mRNA corresponding to several human cyclin-dependent kinases (CDKs). In contrast, compounds 4–8 induced a G1-phase cell cycle arrest without any pronounced effect on CDKs mRNA expression. Interestingly, a non-substituted hydroxy group at C-8 of ring D of the pterocarpan skeleton of compounds 1–3 seems to be important for the CDKs inhibitory activity.

Molecular Mechanisms Related to Hormone Inhibition Resistance in Prostate Cancer

Management of metastatic or advanced prostate cancer has acquired several therapeutic approaches that have drastically changed the course of the disease. In particular due to the high sensitivity of prostate cancer cells to hormone depletion, several agents able to inhibit hormone production or binding to nuclear receptor have been evaluated and adopted in clinical practice. However, despite several hormonal treatments being available nowadays for the management of advanced or metastatic prostate cancer, the natural history of the disease leads inexorably to the development of resistance to hormone inhibition. Findings regarding the mechanisms that drive this process are of particular and increasing interest as these are potentially related to the identification of new targetable pathways and to the development of new drugs able to improve our patients' clinical outcomes.