The insulin-like growth factor (IGF) axis as an anticancer target in prostate cancer

The association between diabetes mellitus and prostate cancer: a meta-analysis and Mendelian randomization

BACKGROUND

Prostate cancer is one of the most common types of cancer in the US, and it has a high mortality rate. Diabetes mellitus is also a dangerous health condition. While some studies have examined the relationship between diabetes mellitus and the risk of prostate cancer, there is still some debate on the matter. This study aims to carefully assess the relationship between prostate cancer and diabetes from both real-world and genetic-level data.

METHODS

This meta-analysis was conducted following the PRISMA 2020 reporting guidelines. The study searched three databases including Medline, Embase and Cochrane. The studies about the incidence risk of prostate cancer with diabetes mellitus were included and used to evaluate the association. The odds ratio (OR), risk ratio (RR) and 95% confidence intervals (95% CI) were estimated using Random Effects models and Fixed Effects models. Mendelian randomization study using genetic variants was also conducted.

RESULTS

A total of 72 articles were included in this study. The results showed that risk of prostate cancer decreased in diabetes patients. And the influence was different in different regions. This study also estimated the impact of body mass index (BMI) in the diabetes populations and found that the risk decreased in higher BMI populations. The MR analysis found that diabetes mellitus exposure reduced the risk of prostate cancer in the European population and Asia populations. Conclusions The diabetes mellitus has a protective effect on prostate cancer. And the influence of obesity in diabetes mellitus plays an important role in this effect.

Insulin-like growth factor family and prostate cancer: new insights and emerging opportunities

Prostate cancer is the second most commonly diagnosed cancer in men. The mammalian insulin-like growth factor (IGF) family is made up of three ligands (IGF-I, IGF-II, and insulin), three receptors (IGF-I receptor (IGF-1R), insulin receptor (IR), and IGF-II receptor (IGF-2R)), and six IGF-binding proteins (IGFBPs). IGF-I and IGF-II were identified as potent mitogens and were previously associated with an increased risk of cancer development including prostate cancer. Several reports showed controversy about the expression of the IGF family and their connection to prostate cancer risk due to the high degree of heterogeneity among prostate tumors, sampling bias, and evaluation techniques. Despite that, it is clear that several IGF family members play a role in prostate cancer development, metastasis, and androgen-independent progression. In this review, we aim to expand our understanding of prostate tumorigenesis and regulation through the IGF system. Further understanding of the role of IGF signaling in PCa shows promise and needs to be considered in the context of a comprehensive treatment strategy.

The nerve growth factor-delivered signals in prostate cancer and its associated microenvironment: when the dialogue replaces the monologue

Prostate cancer (PC) represents the most diagnosed and the second most lethal cancer in men worldwide. Its development and progression occur in concert with alterations in the surrounding tumor microenvironment (TME), made up of stromal cells and extracellular matrix (ECM) that dynamically interact with epithelial PC cells affecting their growth and invasiveness. PC cells, in turn, can functionally sculpt the TME through the secretion of various factors, including neurotrophins. Among them, the nerve growth factor (NGF) that is released by both epithelial PC cells and carcinoma-associated fibroblasts (CAFs) triggers the activation of various intracellular signaling cascades, thereby promoting the acquisition of a metastatic phenotype. After many years of investigation, it is indeed well established that aberrations and/or derangement of NGF signaling are involved not only in neurological disorders, but also in the pathogenesis of human proliferative diseases, including PC. Another key feature of cancer progression is the nerve outgrowth in TME and the concept of nerve dependence related to perineural invasion is currently emerging. NGF released by cancer cells can be a driver of tumor neurogenesis and nerves infiltrated in TME release neurotransmitters, which might stimulate the growth and sustainment of tumor cells.In this review, we aim to provide a snapshot of NGF action in the interactions between TME, nerves and PC cells. Understanding the molecular basis of this dialogue might expand the arsenal of therapeutic strategies against this widespread disease.

MiR-99b regulates cerebral ischemia neuronal injury through targeting IGF1R

BACKGROUND

Recently, microRNA-99b (miR-99b) shows diverse functions in different human disease. However, further studies about the potential effect of miR-99b in cerebral ischemia injury still need to be done.

METHODS

The expressions of miR-99b and IGF1R were detected via RT-qPCR assay. Western blot assay was applied to measure the protein expression of Caspase-3, Bax and Bcl-2. MTT assay was used to observe cell viability of SH-SY5Y cells. The association of miR-99b and IGF1R was testified by dual luciferase assay. And human SH-SY5Y cells were treated with the oxygen-glucose deprivation/reperfusion (OGD/R) to mimic CIR injury.

RESULTS

The expression of miR-99b was increased in the OGD/R model. And upregulation of miR-99b promoted cell viability and inhibited apoptosis induced by OGD/R. Moreover, IGF1R was confirmed as a direct target gene of miR-99b. The expression of IGF1R was obviously decreased under OGD/R conditions.

CONCLUSIONS

MiR-99b promoted the viability and suppressed apoptosis of SH-SY5Y cells under OGD/R conditions through targeting IGF1R.

Emerging Role of IGF-1 in Prostate Cancer: A Promising Biomarker and Therapeutic Target

Prostate cancer (PCa) is a highly heterogeneous disease driven by gene alterations and microenvironmental influences. Not only enhanced serum IGF-1 but also the activation of IGF-1R and its downstream signaling components has been increasingly recognized to have a vital driving role in the development of PCa. A better understanding of IGF-1/IGF-1R activity and regulation has therefore emerged as an important subject of PCa research. IGF-1/IGF-1R signaling affects diverse biological processes in cancer cells, including promoting survival and renewal, inducing migration and spread, and promoting resistance to radiation and castration. Consequently, inhibitory reagents targeting IGF-1/IGF-1R have been developed to limit cancer development. Multiple agents targeting IGF-1/IGF-1R signaling have shown effects against tumor growth in tumor xenograft models, but further verification of their effectiveness in PCa patients in clinical trials is still needed. Combining androgen deprivation therapy or cytotoxic chemotherapeutics with IGF-1R antagonists based on reliable predictive biomarkers and developing and applying novel agents may provide more desirable outcomes. This review will summarize the contribution of IGF-1 signaling to the development of PCa and highlight the relevance of this signaling axis in potential strategies for cancer therapy.

CRISPR/Cas9-mediated deletion of Interleukin-30 suppresses IGF1 and CXCL5 and boosts SOCS3 reducing prostate cancer growth and mortality

BACKGROUND

Metastatic prostate cancer (PC) is a leading cause of cancer death in men worldwide. Targeting of the culprits of disease progression is an unmet need. Interleukin (IL)-30 promotes PC onset and development, but whether it can be a suitable therapeutic target remains to be investigated. Here, we shed light on the relationship between IL30 and canonical PC driver genes and explored the anti-tumor potential of CRISPR/Cas9-mediated deletion of IL30.

METHODS

PC cell production of, and response to, IL30 was tested by flow cytometry, immunoelectron microscopy, invasion and migration assays and PCR arrays. Syngeneic and xenograft models were used to investigate the effects of IL30, and its deletion by CRISPR/Cas9 genome editing, on tumor growth. Bioinformatics of transcriptional data and immunopathology of PC samples were used to assess the translational value of the experimental findings.

RESULTS

Human membrane-bound IL30 promoted PC cell proliferation, invasion and migration in association with STAT1/STAT3 phosphorylation, similarly to its murine, but secreted, counterpart. Both human and murine IL30 regulated PC driver and immunity genes and shared the upregulation of oncogenes, BCL2 and NFKB1, immunoregulatory mediators, IL1A, TNF, TLR4, PTGS2, PD-L1, STAT3, and chemokine receptors, CCR2, CCR4, CXCR5. In human PC cells, IL30 improved the release of IGF1 and CXCL5, which mediated, via autocrine loops, its potent proliferative effect. Deletion of IL30 dramatically downregulated BCL2, NFKB1, STAT3, IGF1 and CXCL5, whereas tumor suppressors, primarily SOCS3, were upregulated. Syngeneic and xenograft PC models demonstrated IL30's ability to boost cancer proliferation, vascularization and myeloid-derived cell infiltration, which were hindered, along with tumor growth and metastasis, by IL30 deletion, with improved host survival. RNA-Seq data from the PanCancer collection and immunohistochemistry of high-grade locally advanced PCs demonstrated an inverse association (chi-squared test, p = 0.0242) between IL30 and SOCS3 expression and a longer progression-free survival of patients with IL30^NegSOCS3^PosPC, when compared to patients with IL30^PosSOCS3^NegPC.

CONCLUSIONS

Membrane-anchored IL30 expressed by human PC cells shares a tumor progression programs with its murine homolog and, via juxtacrine signals, steers a complex network of PC driver and immunity genes promoting prostate oncogenesis. The efficacy of CRISPR/Cas9-mediated targeting of IL30 in curbing PC progression paves the way for its clinical use.

Human bone marrow mesenchymal stem cells-derived exosomes attenuated prostate cancer progression via the miR-99b-5p/IGF1R axis

MicroRNA-99b-5p (miR-99b-5p) has been shown to be enriched in serum exosomes of prostate cancer (PCa) patients treated with radiotherapy, while its function in PCa progression remains unclear. The expression levels of miR-99b-5p in PCa tissues, cancer cell lines and human bone marrow mesenchymal stem cells (HBMSCs), as well as HBMSCs-derived exosomes were assessed by quantitative real-time PCR (qRT-PCR). MiR-99b-5p mimics or inhibitor was transfected into HBMSCs, and HBMSCs-derived exosomes with abnormal expression of miR-99b-5p were used to stimulate PCa cell-line LNCaP cells. Cell proliferative rate was evaluated using Cell Counting Kit-8 (CCK-8) and 5‐ethynyl‐2′‐deoxyuridine (EdU) staining assays. Cell migration and invasion were analyzed by Transwell assay. The epithelial-mesenchymal transition (EMT) was evaluated by detecting EMT-related markers using Western blot analysis. The animal model was constructed to confirm the function of miR-99b-5p in vivo. The expression levels of MiR-99b-5p were decreased in PCa tissues and cell lines, while elevated in HBMSCs-derived exosomes. HBMSCs-derived exosomes significantly inhibited cell malignant phenotypes of PCa cells, and miR-99b-5p mimics transfected HBMSCs further enhanced the inhibitory effects of HBMSCs on PCa progression. In addition, miR-99b-5p inhibitor transfected HBMSCs-derived exosomes promoted the progression of PCa in vitro. Insulin-like growth factor 1 receptor (IGF1R) was identified as a downstream target of miR-99b-5p. Moreover, miR-99b-5p mimics transfected HBMSCs obviously inhibited tumor progression by downregulating IGF1R in animal model in vivo. Our results demonstrated that HBMSCs could attenuate PCa progression, and exosomal miR-99b-5p and IGF1R participated in the regulatory process, contributing to our understanding of the pathogenic mechanism of PCa.

Connecting the Dots Between the Gut-IGF-1-Prostate Axis: A Role of IGF-1 in Prostate Carcinogenesis

Prostate cancer (PCa) is the most common malignancy in men worldwide, thus developing effective prevention strategies remain a critical challenge. Insulin-like growth factor 1 (IGF-1) is produced mainly in the liver by growth hormone signaling and is necessary for normal physical growth. However, several studies have shown an association between increased levels of circulating IGF-1 and the risk of developing solid malignancies, including PCa. Because the IGF-1 receptor is overexpressed in PCa, IGF-1 can accelerate PCa growth by activating phosphoinositide 3-kinase and mitogen-activated protein kinase, or increasing sex hormone sensitivity. Short-chain fatty acids (SCFAs) are beneficial gut microbial metabolites, mainly because of their anti-inflammatory effects. However, we have demonstrated that gut microbiota-derived SCFAs increase the production of IGF-1 in the liver and prostate. This promotes the progression of PCa by the activation of IGF-1 receptor downstream signaling. In addition, the relative abundance of SCFA-producing bacteria, such as Alistipes, are increased in gut microbiomes of patients with high-grade PCa. IGF-1 production is therefore affected by the gut microbiome, dietary habits, and genetic background, and may play a central role in prostate carcinogenesis. The pro-tumor effects of bacteria and diet-derived metabolites might be potentially countered through dietary regimens and supplements. The specific diets or supplements that are effective are unclear. Further research into the "Gut-IGF-1-Prostate Axis" may help discover optimal diets and nutritional supplements that could be implemented for prevention of PCa.

MicroRNAs as the critical regulators of protein kinases in prostate and bladder cancers

Background

Bladder cancer (BCa) and prostate cancer (PCa) are frequent urothelial and genital malignancies with a high ratio of morbidity and mortality which are more common among males. Since BCa and PCa cases are mainly diagnosed in advanced stages with clinical complications, it is required to introduce the efficient early detection markers. Protein kinases are critical factors involved in various cellular processes such as cell growth, motility, differentiation, and metabolism. Deregulation of protein kinases can be frequently observed through the neoplastic transformation and tumor progression. Therefore, kinases are required to be regulated via different genetic and epigenetic processes. MicroRNAs (miRNAs) are among the critical factors involved in epigenetic regulation of protein kinases. Since miRNAs are noninvasive and more stable factors in serum and tissues compared with mRNAs, they can be used as efficient diagnostic markers for the early detection of PCa and BCa.

Main body

In present review, we have summarized all of the reported miRNAs that have been associated with regulation of protein kinases in bladder and prostate cancers.

Conclusions

For the first time, this review highlights the miRNAs as critical factors in regulation of protein kinases during prostate and bladder cancers which paves the way of introducing a noninvasive kinase-specific panel of miRNAs for the early detection of these malignancies. It was observed that the class VIII receptors of tyrosine kinases and non-receptor tyrosine kinases were the most frequent targets for the miRNAs in bladder and prostate cancers, respectively.

Insulin-like growth factor 1 and insulin-like growth factor binding protein 2 serum levels as potential biomarkers in differential diagnosis between chronic pancreatitis and pancreatic adenocarcinoma in reference to pancreatic diabetes

Introduction

Insulin-like growth factor 1 (IGF-1) has been connected with development of pancreatic ductal adenocarcinoma (PDAC).

Aim

To evaluate the serum concentration levels of IGF-1 and insulin-like growth factor binding protein 2 (IGFBP-2) in patients with chronic pancreatitis (CP) and PDAC. Their values in diabetes mellitus (DM) were also assessed.

Material and methods

The study included 83 patients with CP, 92 patients with PDAC, and 20 subjects as a control group. The concentrations of IGF-1 and IGFBP-2 were estimated with ELISA (Corgenix UK Ltd, R&D Systems).

Results

The IGF-1 was higher in CP compared with PDAC (81.11 ±57.18 ng/ml vs. 53.18 ±36.05 ng/ml, p < 0.001), and both CP and PDAC were different from controls (81.11 ±57.18 ng/ml vs. 70.66 ±16.57 ng/ml, p < 0.001 and 53.18 ±36.05 ng/ml vs. 70.66 ±16.57 ng/ml, p < 0.001). CP without cysts have lower IGF-1 compared to those with CP and cysts (60.35 ±34.68 ng/ml vs. 93.55 ±64.78 ng/ml, p < 0.05). IGF-1 in CP without DM was higher compared to IGF-1 in PDAC without DM (91.13 ±65.48 ng/ml vs. 54.75 ±40.41 ng/ml, p < 0.001). In CP and DM the IGF-1 was elevated in comparison to PDAC and DM (62.20 ±32.38 ng/ml vs. 48.45 ±24.88 ng/ml, p < 0.05). IGFBP-2 was higher in CP compared to PDAC (512.42 ±299.77 ng/ml vs 301.59 ±190.36 ng/ml, p < 0.001). In CP and PDAC the IGFBP-2 level was elevated compared to the control group (512.42 ±299.77 ng/ml vs. 51.92 ±29.40 ng/ml, p < 0.001 and 301.59 ±190.36 ng/ml vs. 51.92 ±29.40 ng/ml, p < 0.001). IGFBP-2 in CP without DM was higher compared to PDAC without DM (559.39 ±281.43 vs. 296.53 ±196.93, p < 0.001).

Conclusions

IGF-1 and IGFBP-2 may be biomarkers of CP and PDAC. IGF-1 may be an indicator that signals whether pancreatic diabetes is from CP or PDAC.

Periprostatic adipose tissue promotes prostate cancer resistance to docetaxel by paracrine IGF-1 upregulation of TUBB2B beta-tubulin isoform

Growing evidence supports the pivotal role played by periprostatic adipose tissue (PPAT) in prostate cancer (PCa) microenvironment. We investigated whether PPAT can affect response to Docetaxel (DCTX) and the mechanisms associated. Conditioned medium was collected from the in vitro differentiated adipocytes isolated from PPAT which was isolated from PCa patients, during radical prostatectomy. Drug efficacy was studied by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide citotoxicity assay. Culture with CM of human PPAT (AdipoCM) promotes DCTX resistance in two different human prostate cancer cell lines (DU145 and PC3) and upregulated the expression of BCL-xL, BCL-2, and TUBB2B. AG1024, a well-known IGF-1 receptor inhibitor, counteracts the decreased response to DCTX observed in presence of AdipoCM and decreased TUBB2B expression, suggesting that a paracrine secretion of IGF-1 by PPAT affect DCTX response of PCa cell. Collectively, our study showed that factors secreted by PPAT elicits DCTX resistance through antiapoptotic proteins and TUBB2B upregulation in androgen independent PCa cell lines. These findings reveal the potential of novel therapeutic strategies targeting adipocyte-released factors and IGF-1 axis to overcome DCTX resistance in patients with PCa.

Clinical, Cellular, and Molecular Evidence of the Additive Antitumor Effects of Biguanides and Statins in Prostate Cancer

CONTEXT

Prostate cancer (PCa) is one of the leading causes of cancer-related death among the male population worldwide. Unfortunately, current medical treatments fail to prevent PCa progression in a high percentage of cases; therefore, new therapeutic tools to tackle PCa are urgently needed. Biguanides and statins have emerged as antitumor agents for several endocrine-related cancers.

OBJECTIVE

To evaluate: (1) the putative in vivo association between metformin and/or statins treatment and key tumor and clinical parameters and (2) the direct effects of different biguanides (metformin/buformin/phenformin), statins (atorvastatin/simvastatin/lovastatin), and their combination, on key functional endpoints and associated signalling mechanisms.

METHODS

An exploratory/observational retrospective cohort of patients with PCa (n = 75) was analyzed. Moreover, normal and tumor prostate cells (normal [RWPE-cells/primary prostate cell cultures]; tumor [LNCaP/22RV1/PC3/DU145 cell lines]) were used to measure proliferation/migration/tumorsphere-formation/signalling pathways.

RESULTS

The combination of metformin+statins in vivo was associated to lower Gleason score and longer biochemical recurrence-free survival. Moreover, biguanides and statins exerted strong antitumor actions (ie, inhibition of proliferation/migration/tumorsphere formation) on PCa cells, and that their combination further decreased; in addition, these functional parameters compared with the individual treatments. These actions were mediated through modulation of key oncogenic and metabolic signalling pathways (ie, AR/mTOR/AMPK/AKT/ERK) and molecular mediators (MKI67/cMYC/androgen receptor/cell-cycle inhibitors).

CONCLUSIONS

Biguanides and statins significantly reduced tumor aggressiveness in PCa, with this effect being more potent (in vitro and in vivo) when both compounds are combined. Therefore, given the demonstrated clinical safety of biguanides and statins, our results suggest a potential therapeutic role of these compounds, especially their combination, for the treatment of PCa.

Obesity, Inflammation, and Advanced Prostate Cancer

Obesity is associated with high-grade and advanced prostate cancer. While this association may be multi-factorial, studies suggest that obesity-induced inflammation may play a role in the progression of advanced prostate cancer. The microenvironment associated with obesity increases growth factors and pro-inflammatory cytokines which have been implicated mechanistically to promote invasion, metastasis, and androgen-independent growth. This review summarizes recent findings related to obesity-induced inflammation which may be the link to advanced prostate cancer. In addition, this review while introduce novel targets to mitigate prostate cancer metastasis to the bone. Specific emphasis will be placed on the role of the pro-inflammatory cytokines interleukin (IL)-6, tumor necrosis factor (TNF)α, and IL-1β.

The role of insulin-like growth factors in the development of prostate cancer

INTRODUCTION

Preclinical, clinical, and population studies have provided robust evidence for an important role for the insulin-like growth factor (IGF) system in the development of prostate cancer.

AREAS COVERED

An overview of the IGF system is provided. The evidence implicating the IGF system in the development of prostate cancer is summarized. The compelling evidence culminated in a number of clinical trials of agents targeting the system; the reasons for the failure of these trials are discussed.

EXPERT OPINION

Clinical trials of agents targeting the IGF system in prostate cancer were terminated due to limited objective clinical responses and are unlikely to be resumed unless a convincing predictive biomarker is identified that would enable the selection of likely responders. The aging population and increased screening will lead to greater diagnosis of prostate cancer. Although the vast majority will be indolent disease, the epidemics of obesity and diabetes will increase the proportion that progress to clinical disease. The increased population of worried men will result in more trials aimed to reduce the risk of disease progression; actual clinical endpoints will be challenging and the IGFs remain the best intermediate biomarkers to indicate a response that could alter the course of disease.

Impact of cigarette smoke and aerobic physical training on histological and molecular markers of prostate health in rats

Recent evidence suggests that aerobic physical training may attenuate the deleterious effects of cancer risk factors, including smoking. We investigated the effects of cigarette smoke inhalation and aerobic physical training on the expression of steroid receptors and inflammatory and apoptotic proteins in the prostate. Forty male Wistar rats were distributed in four groups: control (CO), exercise (EXE), cigarette smoke exposure (CS), and cigarette smoke exposure with exercise (CS+EXE). For eight weeks, animals were repeatedly exposed to cigarette smoke for 30 min or performed aerobic physical training either with or without the cigarette smoke inhalation protocol. Following these experiments, we analyzed prostate epithelial morphology and prostatic expression of androgen (AR) and glucocorticoid receptors (GR), insulin-like growth factor (IGF-1), B-cell lymphoma-2 (BCL-2), BCL-2-associated X protein (BAX), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and nuclear factor-kappa B (NF-κB) via immunohistochemistry. Cigarette smoke exposure stimulated the expression of AR, IGF-1, BCL-2, and NF-κB while downregulating BAX, IL-6, and TNF-α labeling in the prostate. In contrast, aerobic physical training attenuated cigarette smoke-induced changes in AR, GR, IGF-1, BCL-2, IL-6, TNF-α, and NF-κB. This suggests that cigarette smoke stimulates inflammation and reduces apoptosis, culminating in increased prostatic epithelial and extracellular matrices, whereas physical training promoted beneficial effects towards maintaining normal prostate morphology and protein levels.

Inhibition of mitochondria ATP synthase suppresses prostate cancer growth through reduced insulin-like growth factor-1 secretion by prostate stromal cells

Modulation of prostate stromal cells (PrSCs) within tumor tissues is gaining attention for the treatment of solid tumors. Using our original in vitro coculture system, we previously reported that leucinostatin (LCS)-A, a peptide mycotoxin, inhibited prostate cancer DU-145 cell growth through reduction of insulin-like growth factor 1 (IGF-I) expression in PrSCs. To further obtain additional bioactive compounds from LCS-A, we designed and synthesized a series of LCS-A derivatives as compounds that target PrSCs. Among the synthesized LCS-A derivatives, LCS-7 reduced IGF-I expression in PrSCs with lower toxicity to PrSCs and mice than LCS-A. As LCS-A has been suggested to interact with mitochondrial adenosine triphosphate (ATP) synthase, a docking study was performed to elucidate the mechanism of reduced IGF-I expression in the PrSCs. As expected, LCS-A and LCS-7 directly interacted with mitochondrial ATP synthase, and like LCS-A and LCS-7, other mitochondrial ATP synthase inhibitors also reduced the expression of IGF-I by PrSCs. Furthermore, LCS-A and LCS-7 significantly decreased the growth of mouse xenograft tumors. Based on these data, we propose that the mitochondrial ATP synthases-IGF-I axis of PrSCs plays a critical role on cancer cell growth and inhibition could be a potential anticancer target for prostate cancer.

MiR-133a-5p inhibits androgen receptor (AR)-induced proliferation in prostate cancer cells via targeting FUsed in Sarcoma (FUS) and AR

Androgens and androgen receptors are vital factors involved in prostate cancer progression, and androgen ablation therapies are commonly employed to treat advanced prostate cancer. Previously, FUsed in Sarcoma (FUS) was identified as an AR-interacting protein that enhances AR transcriptional activity. In the present study, we attempted to identify miRNAs that might target both FUS and AR to inhibit FUS and AR expression. Based on TCGA data and the online tools UALCAN, Kaplan Meier-plotter (KMplot), LncTar and miRWalk prediction, miR-133a-5p was selected. MiR-133a-5p expression was significantly downregulated in prostate cancer, and low miR-133a-5p expression was correlated with low survival probability. As predicted by LncTar and miRWalk, miR-133a-5p could bind to the 3'UTR of FUS and AR to inhibit their expression. MiR-133a-5p overexpression significantly suppressed the cell viability of the AR-positive prostate cancer cell lines VCaP and LNCaP, inhibited the expression of FUS, AR, as well as AR downstream targets IGF1R and EGFR. More importantly, miR-133a inhibition increased cancer cell proliferation as well as the expression of AR and AR downstream factors, while FUS knockdown exerted an opposite effect; the effect of miR-133a on cancer cell proliferation and AR could be significantly reversed by FUS knockdown. Moreover, IGF1R and EGFR knockdown reversed the effect of the miR-133a-5p inhibition. In summary, miR-133a-5p inhibits AR-positive prostate cancer cell proliferation by targeting FUS/AR, thus improving the resistance of prostate cancer to androgen ablation therapies, which requires further in vivo validation. We provided a novel miRNA regulation mechanism for proliferation regulation in AR-positive prostate cancer cells.

MicroRNA-139 is a predictor of prostate cancer recurrence and inhibits growth and migration of prostate cancer cells through cell cycle arrest and targeting IGF1R and AXL

BACKGROUND

We previously identified a panel of five microRNAs (miRNAs) associated with biochemical recurrence and metastasis following prostatectomy from prostate cancer patients using next-generation sequencing-based whole miRNome sequencing and quantitative polymerase chain reaction-based validation analysis. In this study, we examined the mechanism of action of miR-139-5p, one of the downregulated miRNAs identified in the panel.

METHODS

Using a cohort of 585 patients treated with radical prostatectomy, we examined the prognostic significance of miR-139 (dichotomized around the median) using the Kaplan-Meier method and Cox proportional hazard models. We validated these results using The Cancer Genome Atlas (TCGA) data. We created cell lines that overexpressed miR-139 to confirm its targets as well as examine pathways through which miR-139 may function using cell-based assays.

RESULTS

Low miR-139 expression was significantly associated with a variety of prognostic factors in prostate cancer, including Gleason score, pathologic stage, margin positivity, and lymph node status. MiR-139 expression was associated with prognosis: the cumulative incidence of biochemical recurrence and metastasis were significantly lower among patients with high miR-139 expression (P = .0004 and .038, respectively). Validation in the TCGA data set showed a significant association between dichotomized miR-139 expression and biochemical recurrence (odds ratio, 0.52; 95% confidence interval, 0.33-0.82). Overexpression of miR-139 in prostate cancer cells led to a significant reduction in cell proliferation and migration compared with control cells, with cells arrested in G2 of cell cycle. IGF1R and AXL were identified as potential targets of miR-139 based on multiple miRNA-binding sites in 3'-untranslated regions of both the genes and their association with prostate cancer growth pathways. Luciferase assays verified AXL and IGF1R as direct targets of miR-139. Furthermore, immunoblotting of prostate cancer cells demonstrated IGF1R and AXL protein expression were inhibited by miR-139 treatment, which was reversed by the addition of miR-139 antagomir. Examination of the molecular mechanism of growth inhibition by miR-139 revealed the downregulation of activated AKT and cyclin D1, with upregulation of the CDK inhibitor p21.

CONCLUSIONS

miR-139 is associated with improved prognosis in patients with localized prostate cancer, which may be mediated through downregulation of IGF1R and/or AXL and associated signaling pathway components.

Suppression of Prostate Cancer Pathogenesis Using an MDA-9/Syntenin (SDCBP) PDZ1 Small-Molecule Inhibitor

Metastasis is the primary determinant of death in patients with diverse solid tumors and MDA-9/Syntenin (SDCBP), a pro-metastatic and pro-angiogenic gene, contributes to this process. Recently, we documented that by physically interacting with IGF-1R, MDA-9/Syntenin activates STAT3 and regulates prostate cancer pathogenesis. These observations firmly established MDA-9/Syntenin as a potential molecular target in prostate cancer. MDA-9/Syntenin contains two highly homologous PDZ domains predicted to interact with a plethora of proteins, many of which are central to the cancerous process. An MDA-9/Syntenin PDZ1 domain-targeted small molecule (PDZ1i) was previously developed using fragment-based drug discovery (FBDD) guided by NMR spectroscopy and was found to be well-tolerated in vivo, had significant half-life (t _1/2 = 9 hours) and displayed substantial anti-prostate cancer preclinical in vivo activity. PDZ1i blocked tumor cell invasion and migration in vitro, and metastasis in vivo Hence, we demonstrate that PDZ1i an MDA-9/Syntenin PDZ1 target-specific small-molecule inhibitor displays therapeutic potential for prostate and potentially other cancers expressing elevated levels of MDA-9/Syntenin.

Dairy Products: Is There an Impact on Promotion of Prostate Cancer? A Review of the Literature

This review of the literature aims to study potential associations between high consumption of milk and/or dairy products and prostate cancer (PC). Literature is scarce, yet there is a direct relationship between mTORC1 activation and PC; several ingredients in milk/dairy products, when in high concentrations, increase signaling of the mTORC1 pathway. However, there are no studies showing an unequivocal relationship between milk products PC initiation and/or progression. Three different reviews were conducted with articles published in the last 5 years: (M1) PC and intake of dairy products, taking into account the possible mTORC1signaling mechanism; (M2) Intake of milk products and incidence/promotion of PC; (M3) mTORC1 activation signaling pathway, levels of IGF-1 and PC; (M4) mTORC pathway and dairy products. Of the 32 reviews identified, only 21 met the inclusion criteria and were analyzed. There is little scientific evidence that directly link the three factors: incidence/promotion of PC, intake of dairy products and PC, and PC and increased mTORC1 signaling. Persistent hyper-activation of mTORC1 is associated with PC promotion. The activity of exosomal mRNA in cellular communication may lead to different impacts of different types of milk and whether or not mammalian milks will have their own characteristics within each species. Based on this review of the literature, it is possible to establish a relationship between the consumption of milk products and the progression of PC; we also found a possible association with PC initiation, hence it is likely that the intake of dairy products should be reduced or minimized in mens' diet.

IGF2 induces CD133 expression in esophageal cancer cells to promote cancer stemness

Failure to eradicate cancer stem cells (CSC) during primary therapy may lead to cancer recurrence. We recently reported that CD133 is a functional biomarker for CSCs in esophageal squamous cell carcinoma (ESCC) but the molecular pathways critical for maintenance of CD133-positive CSCs are largely unknown. Here, we revealed that knockdown of IGF2 or treatment with PI3K/AKT inhibitors markedly inhibited the abilities of CD133-positive ESCC cells to self-renew, resist chemotherapeutic drugs, and form tumors. Further functional analysis identified miR-377 as a downstream regulator of PI3K/AKT signaling, and a mediator of the effects of IGF2 on CD133 expression and CSC properties. We found that the expression levels of IGF2 and CD133 were positively correlated with each other in primary ESCC, and that concurrent elevation of IGF2 and CD133 expression was significantly associated with poor patient survival. Furthermore, in vivo experiments demonstrated that IGF2-neutralizing antibody enhanced the sensitivity of tumor xenografts in nude mice to 5-fluorouracil treatment. This study underpins the importance of the IGF2-PI3K/AKT-miR-377-CD133 signaling axis in the maintenance of cancer stemness and in the development of novel therapeutic strategy for treatment of esophageal cancer.

The MDA-9/Syntenin/IGF1R/STAT3 Axis Directs Prostate Cancer Invasion

Although prostate cancer is clinically manageable during several stages of progression, survival is severely compromised once cells invade and metastasize to distant organs. Comprehending the pathobiology of invasion is required for developing efficacious targeted therapies against metastasis. Based on bioinformatics data, we predicted an association of melanoma differentiation-associated gene-9 [syntenin, or syndecan binding protein (SDCBP)] in prostate cancer progression. Using tissue samples from various Gleason stage prostate cancer patients with adjacent normal tissue, a series of normal prostate and prostate cancer cell lines (with differing tumorigenic/metastatic properties), mda-9/syntenin-manipulated variants (including loss-of-function and gain-of-function cell lines), and CRISPR/Cas9 stable MDA-9/Syntenin knockout cells, we now confirm the relevance of and dependence on MDA-9/syntenin in prostate cancer invasion. MDA-9/Syntenin physically interacted with insulin-like growth factor-1 receptor following treatment with insulin-like growth factor binding protein-2 (IGFBP2), regulating downstream signaling processes that enabled STAT3 phosphorylation. This activation enhanced expression of MMP2 and MMP9, two established enzymes that positively regulate invasion. In addition, MDA-9/syntenin-mediated upregulation of proangiogenic factors including IGFBP2, IL6, IL8, and VEGFA also facilitated migration of prostate cancer cells. Collectively, our results draw attention to MDA-9/Syntenin as a positive regulator of prostate cancer metastasis, and the potential application of targeting this molecule to inhibit invasion and metastasis in prostate cancer and potentially other cancers.Significance: This study provides new mechanistic insight into the proinvasive role of MDA-9/Syntenin in prostate cancer and has potential for therapeutic application to prevent prostate cancer metastasis. Cancer Res; 78(11); 2852-63. ©2018 AACR.

IDH1R132H Promotes Malignant Transformation of Benign Prostatic Epithelium by Dysregulating MicroRNAs: Involvement of IGF1R-AKT/STAT3 Signaling Pathway

Risk stratification using molecular features could potentially help distinguish indolent from aggressive prostate cancer (PCa). Mutations in isocitrate dehydrogenase (IDH) acquire an abnormal enzymatic activity, resulting in the production of 2-hydroxyglutarate and alterations in cellular metabolism, histone modification, and DNA methylation. Mutant IDH1 has been identified in various human malignancies, and IDH1R132H constituted the vast majority of mutational events of IDH1. Most recent studies suggested that IDH1 mutations define a methylator subtype in PCa. However, the function of IDH1R132H in PCa development and progression is largely unknown. In this study, we showed that the prevalence of IDH1R132H in Chinese PCa patients is 0.6% (2/336). Of note, IDH1R132H-mutant PCa patients lacked other canonical genomic lesions (e.g., ERG rearrangement, PTEN deletion) that are common in most other PCa patients. The in vitro experiment suggested that IDH1R132H can promote proliferation of benign prostate epithelial cell RWPE-1 when under the situation of low cytokine. It could also promote migration capacity of RWPE-1 cells. Mechanistically, IDH1R132H was an important regulator of insulin-like growth factor 1receptor (IGF1R) by downregulating a set of microRNAs (miR-141-3p, miR-7-5p, miR-223-3p). These microRNAs were repressed by the alteration of epigenetic modification to decrease the enrichment of active marker H3K4me3 or to increase repressive marker H3K27me3 at their promoters. Collectively, we proposed a novel model for an IDH1R132H-microRNAs-IGF1R regulatory axis, which might provide insight into the function of IDH1R132H in PCa development.

The insulin-like growth factor system in multiple myeloma: diagnostic and therapeutic potential

Multiple myeloma (MM) is a highly heterogeneous plasma cell malignancy. The MM cells reside in the bone marrow (BM), where reciprocal interactions with the BM niche foster MM cell survival, proliferation, and drug resistance. As in most cancers, the insulin-like growth factor (IGF) system has been demonstrated to play a key role in the pathogenesis of MM. The IGF system consists of IGF ligands, IGF receptors, IGF binding proteins (IGFBPs), and IGFBP proteases and contributes not only to the survival, proliferation, and homing of MM cells, but also MM-associated angiogenesis and osteolysis. Furthermore, increased IGF-I receptor (IGF-IR) expression on MM cells correlates with a poor prognosis in MM patients. Despite the prominent role of the IGF system in MM, strategies targeting the IGF-IR using blocking antibodies or small molecule inhibitors have failed to translate into the clinic. However, increasing preclinical evidence indicates that IGF-I is also involved in the development of drug resistance against current standard-of-care agents against MM, including proteasome inhibitors, immunomodulatory agents, and corticoids. IGF-IR targeting has been able to overcome or revert this drug resistance in animal models, enhancing the efficacy of standard-of-care agents. This finding has generated renewed interest in the therapeutic potential of IGF-I targeting in MM. The present review provides an update of the impact of the different IGF system components in MM and discusses the diagnostic and therapeutic potentials.

Insulin-like growth factor 2 expression in prostate cancer is regulated by promoter-specific methylation

Deregulation of the insulin-like growth factor (IGF) axis and dysbalance of components of the IGF system as potential therapeutic targets have been described in different tumor types. IGF2 is a major embryonic growth factor and an important activator of IGF signaling. It is regulated by imprinting in a development- and tissue-dependent manner and has been implicated in a broad range of malignancies including prostate cancer (PCa). Loss of imprinting (LOI) usually results in bi-allelic gene expression and increased levels of IGF2. However, the regulatory mechanisms and the pathophysiological impact of altered IGF2 expression in PCa remain elusive. Here, we show that in contrast to many other tumors, IGF2 mRNA and protein levels were decreased in 80% of PCa in comparison with non-neoplastic adjacent prostate and were independent of LOI status. Instead, IGF2 expression in both tumors and adjacent prostate depended on preferential usage of the IGF2 promoters P3 and P4. Decreased IGF2 expression in tumors was strongly related to hypermethylation of these two promoters. Methylation of the A region in promoter P4 correlated specifically with IGF2 expression in the 20% of PCa where IGF2 was higher in tumors than in adjacent prostate. We conclude that IGF2 is downregulated in most PCa and may be particularly relevant during early stages of tumor development or during chemotherapy and androgen deprivation. PCa differs from other tumors in that IGF2 expression is mainly regulated through methylation of promoter-specific and not by imprinting. Targeting of promoter-specific regions may have relevance for the adjuvant treatment of PCa.

The anti-tumorigenic activity of A2M-A lesson from the naked mole-rat

Cancer resistance is a major cause for longevity of the naked mole-rat. Recent liver transcriptome analysis in this animal compared to wild-derived mice revealed higher expression of alpha2-macroglobulin (A2M) and cell adhesion molecules, which contribute to the naked mole-rat’s cancer resistance. Notably, A2M is known to dramatically decrease with age in humans. We hypothesize that this might facilitate tumour development. Here we found that A2M modulates tumour cell adhesion, migration and growth by inhibition of tumour promoting signalling pathways, e.g. PI3K / AKT, SMAD and up-regulated PTEN via down-regulation of miR-21, in vitro and in tumour xenografts. A2M increases the expression of CD29 and CD44 but did not evoke EMT. Transcriptome analysis of A2M-treated tumour cells, xenografts and mouse liver demonstrated a multifaceted regulation of tumour promoting signalling pathways indicating a less tumorigenic environment mediated by A2M. By virtue of these multiple actions the naturally occurring A2M has strong potential as a novel therapeutic agent.

Phase II prospective randomized trial of weight loss prior to radical prostatectomy

BACKGROUND

Obesity is associated with poorly differentiated and advanced prostate cancer and increased mortality. In preclinical models, caloric restriction delays prostate cancer progression and prolongs survival. We sought to determine if weight loss (WL) in men with prostate cancer prior to radical prostatectomy affects tumor apoptosis and proliferation, and if WL effects other metabolic biomarkers.

METHODS

In this Phase II prospective trial, overweight and obese men scheduled for radical prostatectomy were randomized to a 5–8 week WL program consisting of standard structured energy-restricted meal plans (1200–1500 Kcal/day) and physical activity or to a control group. The primary endpoint was apoptotic index in the radical prostatectomy malignant epithelium. Secondary endpoints were proliferation (Ki67) in the radical prostatectomy tissue, body weight, body mass index (BMI), waist to hip ratio, body composition, and serum PSA, insulin, triglyceride, cholesterol, testosterone, estradiol, leptin, adiponectin, interleukin 6, interleukin 8, insulin-like growth factor 1, and IGF binding protein 1.

RESULTS

Twenty-three patients were randomized to the WL intervention and twenty-one patients to the control group. Subjects in the intervention group had significantly more weight loss (WL:−3.7 ± 0.5 kg; Control:−1.6 ± 0.5 kg; p=0.007) than the control group and total fat mass was significantly reduced (WL:−2.1 ± 0.4; Control: 0.1 ± 0.3; p=0.015). There was no significant difference in apoptotic or proliferation index between the groups. Among the other biomarkers, triglyceride and insulin levels were significantly decreased in the WL compared to the control group.

CONCLUSIONS

In summary, this short-term WL program prior to radical prostatectomy resulted in significantly more WL in the intervention vs. the control group and was accompanied by significant reductions in body fat mass, circulating triglycerides, and insulin. However, no significant changes were observed in malignant epithelium apoptosis or proliferation. Future studies should consider a longer term or more intensive weight loss intervention.

Insulin-like growth factor-I induces chemoresistence to docetaxel by inhibiting miR-143 in human prostate cancer

Elevated levels of insulin-like growth factor-I (IGF-I) are associated with carcinogenesis and cancer progression. However, the molecular mechanisms by which IGF-I promotes prostate cancer development remain to be elucidated. Docetaxel chemotherapy is an important therapeutic strategy in many types of human cancers including prostate cancer. In this study, we showed that IGF-I rendered PC-3 and DU145 cells more resistant to docetaxel treatment. IGF-I treatment decreased miR-143 expression, but increased the expression levels of IGF-I receptor (IGF-IR) and insulin receptor substrate 1 (IRS1), direct targets of miR-143. Overexpression of miR-143 abolished IGF-I-induced chemoresistance to docetaxel treatment, decreased expression levels of IGF-I, IRS1, and vascular endothelial growth factor (VEGF) in prostate cancer cell lines. Furthermore, docetaxel treatment significantly inhibited VEGF transcriptional activation, whereas IGF-I treatment induced VEGF transcriptional activation in a dose-dependent manner. Forced expression of IGF-IR and IRS1 cDNAs without the 3’ UTR regions restored miR-143-inhibited VEGF transcriptional activation. Finally, miR-143 inhibited tumor growth and made cells more sensitive to docetaxel treatment for decreasing tumor growth in vivo. Taken together, our data demonstrates that IGF-I induces docetaxel resistance and upregulates IGF-IR and IRS1 expression through miR-143 downregulation, whereas miR-143 acts as a tumor suppressor by targeting its targets IGF-IR and IRS1.

Inhibition of the insulin-like growth factor-1 receptor potentiates acute effects of castration in a rat model for prostate cancer growth in bone

Prostate cancer (PCa) patients with bone metastases are primarily treated with androgen deprivation therapy (ADT). Less pronounced ADT effects are seen in metastases than in primary tumors. To test if acute effects of ADT was enhanced by concurrent inhibition of pro-survival insulin-like growth factor 1 (IGF-1), rats were inoculated with Dunning R3327-G tumor cells into the tibial bone marrow cavity and established tumors were treated with castration in combination with IGF-1 receptor (IGF-1R) inhibitor NVP-AEW541, or by each treatment alone. Dunning R3327-G cells were stimulated by androgens and IGF-1 in vitro. In rat tibia, Dunning R3327-G cells induced bone remodeling, identified through increased immunoreactivity of osteoblast and osteoclast markers. Tumor cells occasionally grew outside the tibia, and proliferation and apoptotic rates a few days after treatment were evaluated by scoring BrdU- and caspase-3-positive tumor cells inside and outside the bone marrow cavity, separately. Apoptosis was significantly induced outside, but unaffected inside, the tibial bone by either castration or NVP-AEW541, and the maximum increase (2.7-fold) was obtained by the combined treatment. Proliferation was significantly reduced by NVP-AEW541, independently of growth site, although the maximum decrease (24%) was observed when NVP-AEW541 was combined with castration. Tumor cell IGF-1R immunoreactivity was evaluated in clinical PCa bone metastases (n = 61), and positive staining was observed in most cases (74%). In conclusion, IGF-1R inhibition may be evaluated in combination with ADT in patients with metastatic PCa, or in combination with therapies for the subsequent development of castration-resistant disease, although diverse responses could be anticipated depending on metastasis site.

PSMA redirects cell survival signaling from the MAPK to the PI3K-AKT pathways to promote the progression of prostate cancer

Increased abundance of the prostate-specific membrane antigen (PSMA) on prostate epithelium is a hallmark of advanced metastatic prostate cancer (PCa) and correlates negatively with prognosis. However, direct evidence that PSMA functionally contributes to PCa progression remains elusive. We generated mice bearing PSMA-positive or PSMA-negative PCa by crossing PSMA-deficient mice with transgenic PCa (TRAMP) models, enabling direct assessment of PCa incidence and progression in the presence or absence of PSMA. Compared with PSMA-positive tumors, PSMA-negative tumors were smaller, lower-grade, and more apoptotic with fewer blood vessels, consistent with the recognized proangiogenic function of PSMA. Relative to PSMA-positive tumors, tumors lacking PSMA had less than half the abundance of type 1 insulin-like growth factor receptor (IGF-1R), less activity in the survival pathway mediated by PI3K-AKT signaling, and more activity in the proliferative pathway mediated by MAPK-ERK1/2 signaling. Biochemically, PSMA interacted with the scaffolding protein RACK1, disrupting signaling between the β₁ integrin and IGF-1R complex to the MAPK pathway, enabling activation of the AKT pathway instead. Manipulation of PSMA abundance in PCa cell lines recapitulated this signaling pathway switch. Analysis of published databases indicated that IGF-1R abundance, cell proliferation, and expression of transcripts for antiapoptotic markers positively correlated with PSMA abundance in patients, suggesting that this switch may be relevant to human PCa. Our findings suggest that increase in PSMA in prostate tumors contributes to progression by altering normal signal transduction pathways to drive PCa progression and that enhanced signaling through the IGF-1R/β₁ integrin axis may occur in other tumors.

Molecular signaling involving intrinsically disordered proteins in prostate cancer

Investigations on cellular protein interaction networks (PINs) reveal that proteins that constitute hubs in a PIN are notably enriched in Intrinsically Disordered Proteins (IDPs) compared to proteins that constitute edges, highlighting the role of IDPs in signaling pathways. Most IDPs rapidly undergo disorder-to-order transitions upon binding to their biological targets to perform their function. Conformational dynamics enables IDPs to be versatile and to interact with a broad range of interactors under normal physiological conditions where their expression is tightly modulated. IDPs are involved in many cellular processes such as cellular signaling, transcriptional regulation, and splicing; thus, their high-specificity/low-affinity interactions play crucial roles in many human diseases including cancer. Prostate cancer (PCa) is one of the leading causes of cancer-related mortality in men worldwide. Therefore, identifying molecular mechanisms of the oncogenic signaling pathways that are involved in prostate carcinogenesis is crucial. In this review, we focus on the aspects of cellular pathways leading to PCa in which IDPs exert a primary role.

Controversies in the risk of neoplasia in GH deficiency

Growth hormone (GH) replacement in GH deficient (GHD) children secures normal linear growth, while in GHD adults it improves metabolic status, body composition and quality of life. Safety of GH treatment is an important issue in particular concerning the controversy of potential cancer risk. Unlike in congenital IGF-1 deficiency, there is no complete protection against cancer in GHD patients. Important modifiable risk factors in GHD patients are obesity, insulin resistance, sedentary behavior, circadian rhythm disruption, chronic low grade inflammation and concomitant sex hormone replacement. Age, family history, hereditary cancer predisposition syndromes or cranial irradiation may present non-modifiable risk factors. Quantifying the risk of cancer in relation to GH therapy in adult GHD patients is complex. There is evidence that links GH to cancer occurrence or promotion, but the evidence is progressively weaker when moving from in vitro studies to in vivo animal studies to epidemiological studies and finally to studies on GH treated patients. GH-IGF inhibition in experimental animals leads to decreased cancer incidence and progression. Epidemiological studies suggest an association of high normal circulating IGF-1 or GH to cancer incidence in general population. Data regarding cancer incidence in acromegaly are inconsistent but thyroid and colorectal neoplasias are the main source of concern. Replacement therapy with rhGH for GHD is generally safe. Overall the rate of de novo cancers was not increased in studies of GH-treated GHD patients. Additional caution is mandated in patients with history of cancer, strong family history of cancer and with advancing age. Childhood cancer survivors may be at increased risk for secondary neoplasms compared with general population. In this subgroup GH therapy should be used cautiously and with respect to other risk factors (cranial irradiation etc). We believe that the benefits of GH therapy against the morbidity of untreated GH deficiency outweigh the theoretical cancer risk. Proper monitoring of GH treatment with diligent cancer surveillance remains essential.

Proteomics analysis of vesicles isolated from plasma and urine of prostate cancer patients using a multiplex, aptamer-based protein array

Proteomics analysis of biofluid-derived vesicles holds enormous potential for discovering non-invasive disease markers. Obtaining vesicles of sufficient quality and quantity for profiling studies has, however, been a major problem, as samples are often replete with co-isolated material that can interfere with the identification of genuine low abundance, vesicle components. Here, we used a combination of ultracentrifugation and size-exclusion chromatography to isolate and analyse vesicles of plasma or urine origin. We describe a sample-handling workflow that gives reproducible, quality vesicle isolations sufficient for subsequent protein profiling. Using a semi-quantitative aptamer-based protein array, we identified around 1,000 proteins, of which almost 400 were present at comparable quantities in plasma versus urine vesicles. Significant differences were, however, apparent with elements like HSP90, integrin αVβ5 and Contactin-1 more prevalent in urinary vesicles, while hepatocyte growth factor activator, prostate-specific antigen–antichymotrypsin complex and many others were more abundant in plasma vesicles. This was also applied to a small set of specimens collected from men with metastatic prostate cancer, highlighting several proteins with the potential to indicate treatment refractory disease. The study provides a practical platform for furthering protein profiling of vesicles in prostate cancer, and, hopefully, many other disease scenarios.

The Influence of Exercise on the Insulin-like Growth Factor Axis in Oncology: Physiological Basis, Current, and Future Perspectives

Exercise and physical activity have been shown to reduce the risk of many common cancers and strongly influence tumor biology. A cause-effect mechanism explaining this relationship is dependent on cellular pathways that can influence tumor growth and are exercise responsive. The insulin-like growth factor (IGF) axis is reported to promote the development and progression of carcinomas through cellular signaling in cancerous tissues. This review summarizes the physiologic basis of the role of the IGF axis in oncology and the influence of exercise on this process. We examined the effects of exercise prescription on the IGF axis in cancer survivors by evaluating the current scope of the literature. The current research demonstrates a remarkable heterogeneity and inconsistency in the responses of the IGF axis to exercise in breast, prostate, and colorectal cancer survivors. Finally, this review presents an in-depth exploration of the physiologic basis and mechanistic underpinnings of the seemingly disparate relationship between exercise and the IGF axis in oncology. Although there is currently insufficient evidence to categorize the effects of exercise prescription on the IGF axis in cancer survivors, the inconsistency of results suggests a multifaceted relationship, the complexities of which are considered in this review.

Both IGF1R and INSR Knockdown Exert Antitumorigenic Effects in Prostate Cancer In Vitro and In Vivo

The IGF network with its main receptors IGF receptor 1 (IGF1R) and insulin receptor (INSR) is of major importance for cancer initiation and progression. To date, clinical studies targeting this network were disappointing and call for thorough analysis of the IGF network in cancer models. We highlight the oncogenic effects controlled by IGF1R and INSR in prostate cancer cells and show similarities as well as differences after receptor knockdown (KD). In PC3 prostate cancer cells stably transduced with inducible short hairpin RNAs, targeting IGF1R or INSR attenuated cell growth and proliferation ultimately driving cells into apoptosis. IGF1R KD triggered rapid and strong antiproliferative and proapoptotic responses, whereas these effects were less pronounced and delayed after INSR KD. Down-regulation of the antiapoptotic proteins myeloid cell leukemia-1 and survivin was observed in both KDs, whereas IGF1R KD also attenuated expression of prosurvival proteins B cell lymphoma-2 and B cell lymphoma-xL. Receptor KD induced cell death involved autophagy in particular upon IGF1R KD; however, no difference in mitochondrial energy metabolism was observed. In a mouse xenograft model, induction of IGF1R or INSR KD after tumor establishment eradicated most of the tumors. After 20 days of receptor KD, tumor cells were found only in 1/14 IGF1R and 3/14 INSR KD tumor remnants. Collectively, our data underline the oncogenic functions of IGF1R and INSR in prostate cancer namely growth, proliferation, and survival in vitro as well as in vivo and identify myeloid cell leukemia-1 and survivin as important mediators of inhibitory and apoptotic effects.