Insulin-like Growth Factor Pathway Genetic Polymorphisms, Circulating IGF1 and IGFBP3, and Prostate Cancer Survival

Endocrine and cellular physiology and pathology of the insulin-like growth factor acid-labile subunit

The acid-labile subunit (ALS) of the insulin-like growth factor (IGF) binding protein (IGFBP) complex, encoded in humans by IGFALS, has a vital role in regulating the endocrine transport and bioavailability of IGF-1 and IGF-2. Accordingly, ALS has a considerable influence on postnatal growth and metabolism. ALS is a leucine-rich glycoprotein that forms high-affinity ternary complexes with IGFBP-3 or IGFBP-5 when they are occupied by either IGF-1 or IGF-2. These complexes constitute a stable reservoir of circulating IGFs, blocking the potentially hypoglycaemic activity of unbound IGFs. ALS is primarily synthesized by hepatocytes and its expression is lower in non-hepatic tissues. ALS synthesis is strongly induced by growth hormone and suppressed by IL-1β, thus potentially serving as a marker of growth hormone secretion and/or activity and of inflammation. IGFALS mutations in humans and Igfals deletion in mice cause modest growth retardation and pubertal delay, accompanied by decreased osteogenesis and enhanced adipogenesis. In hepatocellular carcinoma, IGFALS is described as a tumour suppressor; however, its contribution to other cancers is not well delineated. This Review addresses the endocrine physiology and pathology of ALS, discusses the latest cell and proteomic studies that suggest emerging cellular roles for ALS and outlines its involvement in other disease states.

Autocrine IGF-II-Associated Cancers: From a Rare Paraneoplastic Event to a Hallmark in Malignancy

The paraneoplastic syndrome referred in the literature as non-islet-cell tumor hypoglycemia (NICTH) and extra-pancreatic tumor hypoglycemia (EPTH) was first reported almost a century ago, and the role of cancer-secreted IGF-II in causing this blood glucose-lowering condition has been widely established. The landscape emerging in the last few decades, based on molecular and cellular findings, supports a broader role for IGF-II in cancer biology beyond its involvement in the paraneoplastic syndrome. In particular, a few key findings are constantly observed during tumorigenesis, (a) a relative and absolute increase in fetal insulin receptor isoform (IRA) content, with (b) an increase in IGF-II high-molecular weight cancer-variants (big-IGF-II), and (c) a stage-progressive increase in the IGF-II autocrine signal in the cancer cell, mostly during the transition from benign to malignant growth. An increasing and still under-exploited combinatorial pattern of the IGF-II signal in cancer is shaping up in the literature with respect to its transducing receptorial system and effector intracellular network. Interestingly, while surgical and clinical reports have traditionally restricted IGF-II secretion to a small number of solid malignancies displaying paraneoplastic hypoglycemia, a retrospective literature analysis, along with publicly available expression data from patient-derived cancer cell lines conveyed in the present perspective, clearly suggests that IGF-II expression in cancer is a much more common event, especially in overt malignancy. These findings strengthen the view that (1) IGF-II expression/secretion in solid tumor-derived cancer cell lines and tissues is a broader and more common event compared to the reported IGF-II association to paraneoplastic hypoglycemia, and (2) IGF-II associates to the commonly observed autocrine loops in cancer cells while IGF-I cancer-promoting effects may be linked to its paracrine effects in the tumor microenvironment. Based on these evidence-centered considerations, making the autocrine IGF-II loop a hallmark for malignant cancer growth, we here propose the functional name of IGF-II secreting tumors (IGF-IIsT) to overcome the view that IGF-II secretion and pro-tumorigenic actions affect only a clinical sub-group of rare tumors with associated hypoglycemic symptoms. The proposed scenario provides an updated logical frame towards biologically sound therapeutic strategies and personalized therapeutic interventions for currently unaccounted IGF-II-producing cancers.

Hsa_circ_0046263 functions as a ceRNA to promote nasopharyngeal carcinoma progression by upregulating IGFBP3

Accumulating evidences indicate that circular RNAs (circRNAs), a subclass of noncoding RNAs, play important role in regulating gene expression in eukaryotes. Hsa_circ_0046263 (circ-0046263) was found aberrantly expressed in nasopharyngeal carcinoma (NPC), but its role in tumor growth and metastasis remains largely unclear. Sanger sequencing, RNase R assay, and nucleic acid electrophoresis were conducted to verify the identification of circ-0046263. Nuclear separation and fluorescence in situ hybridization (FISH) assays were used to determine the localization of circ-004263. Dual luciferase reporter and RNA immunoprecipitation (RIP) were employed to confirm the binding of circ-0046263 with miR-133a-5p. Colony formation, proliferation, wound healing, transwell, western blot, and in vivo tumor growth and metastasis assays were performed to assess the roles of circ-0046263, miR-133a-5p, IGFBP3 and their interactions in NPC cells. Circ-0046263 was upregulated in both NPC cell lines and tissues. The in vitro functional studies revealed that knockdown of circ-0046263 inhibited the proliferation, invasion, and migration of NPC cells, whereas its overexpression produced the opposite result. In vivo experiments indicated that knockdown or overexpression of circ-0046263 attenuated or promoted tumor growth and metastasis, respectively. Mechanistically, circ-0046263 could act as a miRNA sponge to absorb miR-133a-5p and upregulate the expression of miRNA downstream target IGFBP3. In addition, miR-133a-5p inhibition or IGFBP3 overexpression could rescue the malignant behavior induced by circ-0046263 silencing. Finally, circ-0046263 plays a tumor-promoting role in NPC to enhance malignant behavior through the miR-133a-5p/IGFBP3 axis, which could be a potential target for NPC therapy.

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.

lncRNA IGF2-AS Promotes Cell Proliferation, Migration, and Invasion of Gastric Cancer by Modulating miR-937/EZH2 Axis

The article entitled, "lncRNA IGF2-AS Promotes Cell Proliferation, Migration, and Invasion of Gastric Cancer by Modulating miR-937/EZH2 Axis," by Zizi Li, Zhanyu Li, Zhijuan Zhong, Jianhui Zhou, Shenhao Huang, Wenying Zhou, and Jianfeng Xu (Cancer Biother Radiopharm epub 25 May 2020; Doi: 10.1089/cbr.2019.3275) is being officially retracted from the literature. The Editor-in-Chief of Cancer Biotherapy and Radiopharmaceuticals (CBR) received an email from the corresponding author of the article, Wenying Zhou, on September 7, 2020, indicating: "…this manuscript should no longer be published [because of] information from our superior and also after discussion with my research team, we want to repeat our experiment and then revise the [manuscript]. Our team has a lot of controversy about these results. In order to ensure the quality of the data and not to mislead readers, we decided to [retract] the manuscript. We will be more rigorous in our further study." The editor requested further information about precisely which data could not be reproduced, to which Dr. Wenying Zhou responded: "…we found that the results of Figure 4B and 4C, Figure 5A and 5B could not be repeated. Our repeated results of Figure 4B and 4C were as follow[s]: compared with miR-NC group, there was no significant decrease of the luciferase activity in miR-937 group when cells co-transfected with EZH2 3'-UTR-WT. Our repeated results of Figure 5A and 5B were as follow[s]: miR-937 inhibited the proliferation of MNK-28 and SGC-7901 cells, but the cell proliferation had no significant change in miR-937+EZH2 group compared with miR-937+pcDNA group. These findings resulted in the uncertainty of the targeted relationship between miR-937 and EZH2. We also repeated these experiments in different environments, but they all contradict the results in the original data. So, the conclusion is very controversial. In a responsible attitude to the readers, we decide to [retract] the manuscript." The authors have extended their apologies to the Editor and to the readers of CBR. Though in the author's original email, the request was made to "withdraw" the paper, CBR has decided to fully retract it due to irreproducible data, as the journal is committed to preserving the scientific literature and the community it serves.

Pre-diagnostic Serum Metabolomic Profiling of Prostate Cancer Survival

Impaired metabolism may play a role in the development and lethality of prostate cancer, yet a comprehensive analysis of the interrelationships appears lacking. We measured 625 metabolites using ultrahigh performance liquid chromatography/mass spectrometry (LC-MS) and gas chromatography/mass spectrometry (GC-MS) of prediagnostic serum from 197 prostate cancer cases in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention (ATBC) Study (ages at diagnosis, 55-86 years). Cox proportional hazards models estimated associations between circulating metabolites and prostate cancer mortality for 1 SD differences (log-metabolite scale), adjusted for age, year of diagnosis, and disease stage. Associations between metabolite chemical classes and survival were examined through pathway analysis, and Cox models assessed the relationship with a sterol/steroid metabolite principal component analysis factor score. Elevated serum N-oleoyl taurine was significantly associated with prostate cancer-specific mortality (hazard ratios [HR] = 1.72 per 1 SD, p < .00008, Bonferroni-corrected threshold = 0.05/625; HR = 3.6 for highest vs lowest tertile, p < .001). Pathway analyses revealed a statistically significant association between lipids and prostate cancer death (p < .006, Bonferroni-corrected threshold = 0.05/8), and sterol/steroid metabolites showed the strongest chemical sub-class association (p = .0014, Bonferroni-corrected threshold = 0.05/45). In the principal component analysis, a 1-SD increment in the sterol/steroid metabolite score increased the risk of prostate cancer death by 46%. Prediagnostic serum N-oleoyl taurine and sterol/steroid metabolites were associated with prostate cancer survival.

IGF signalling in germ cells and testicular germ cell tumours: roles and therapeutic approaches

The insulin-like growth factor (IGF) axis plays key roles in normal tissue growth and development as well as in the progression of several tumour types and their subsequent growth and progression to a metastatic phenotype. This review explores the role of IGF system in normal germ cell development and function in addition to examining the evidence for deregulation of IGF signalling in cancer, with particular relevance to evidence supporting a role in testicular germ cell tumours (TGCTs). Despite the clear preclinical rationale for targeting the IGF axis in cancer, there has been a lack of progress in identifying which patients may benefit from such therapy. Future employment of agents targeting the IGF pathway is expected to concentrate on their use in combination with other treatments to prevent resistance and exploit their potential as chemo- and radiosensitizers.

Expression of IGF/insulin receptor in prostate cancer tissue and progression to lethal disease

Circulating insulin-like growth factor-1 (IGF-1) is consistently associated with prostate cancer risk. IGF-1 binds to IGF-1 receptor (IGF1R) and insulin receptor (IR), activating cancer hallmark pathways. Experimental evidence suggests that TMPRSS2:ERG may interact with IGF/insulin signaling to influence progression. We investigated IGF1R and IR expression and its association with lethal prostate cancer among 769 men. Protein expression of IGF1R, IR and ERG (i.e. a surrogate of ERG fusion genes) were assayed by immunohistochemistry. Cox models estimated hazard ratios (HR) and 95% confidence intervals (CI) adjusted for clinical characteristics. Among patients, 29% had strong tumor IGF1R expression and 10% had strong IR expression. During a mean follow-up of 13.2 years through 2012, 80 men (11%) developed lethal disease. Tumors with strong IGF1R or IR expression showed increased cell proliferation, decreased apoptosis and a higher prevalence of ERG. In multivariable models, strong IGF1R was associated with a borderline increased risk of lethal prostate cancer (HR 1.7; 95% CI 0.9-3.1). The association appeared greater in ERG-positive tumors (HR 2.8; 95% CI 0.9-8.4) than in ERG-negative tumors (HR 1.3; 95% CI 0.6-3.0, p-heterogeneity 0.08). There was no association between IR and lethal prostate cancer (HR 0.8; 95% CI 0.4-1.9). These results suggest that tumor IGF1R expression may play a role in prostate cancer progression to a lethal phenotype and that ERG-positive tumors may be more sensitive to IGF signaling. These data may improve our understanding of IGF signaling in prostate cancer and suggest therapeutic options for disease subtypes.

Association between serum levels of insulin-like growth factor-1, bioavailable testosterone, and pathologic Gleason score

BACKGROUND

We evaluated the association between serum levels of insulin-like growth factor-1 (IGF-1), bioavailable testosterone, and surgical Gleason score (GS).

METHODS

We analyzed 793 patients who underwent radical prostatectomy and 272 men with negative prostate biopsy. Serum levels of IGF-1 and testosterone were measured before surgery or biopsy.

RESULTS

The mean IGF-1 levels of prostate cancer patients and men with a negative biopsy were 143.8 and 118.9 ng/mL, respectively (P < 0.001). Men with high serum IGF-1 were more likely to have prostate cancer (highest vs lowest quartile, odds ratio [OR] = 3.35; Ptrend  < 0.001). However, among men with prostate cancer, the mean IGF-1 levels of those with low (GS ≤ 6), intermediate (GS = 7), and high surgical GS (GS ≥8) were 151.7, 144.1, and 132.9 ng/mL, respectively (P < 0.001). Using quartile analysis, high serum IGF-1 levels were shown to be associated with a low risk of high surgical GS (OR = 0.464; Ptrend  = 0.006). Serum bioavailable testosterone concentration was positively correlated with serum IGF-1 level (r = 0.157, P < 0.001). High bioavailable testosterone level was also associated with a low risk of high surgical GS in patients without diabetes mellitus (OR = 0.569; Ptrend  = 0.040). Among men with biopsy GS ≤ 3 + 4 (n = 460), upgrading to high surgical GS was more frequent in patients with low IGF-1 level (≤116.0 ng/mL; 9.9%) or low bioavailable testosterone level (≤0.85 ng/mL; 9.3%) than in patients with normal IGF-1 and bioavailable testosterone levels (2.6%; P = 0.004).

CONCLUSIONS

Serum levels of IGF-1 and bioavailable testosterone show inverse associations with high surgical GS. This suggests that high-grade prostate cancer develops independently of these two substances.

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.

Long non-coding RNA Igf2as controls hepatocellular carcinoma progression through the ERK/MAPK signaling pathway

Long non-coding RNAs (lncRNAs) serve an important role in numerous human diseases, including cancer. Abnormal expression of lncRNAs has been associated with a number of tumor types; however, the underlying mechanisms through which lncRNA functions have yet to be elucidated. The present study primarily focuses on insulin-like growth factor 2 antisense 1 (Igf2as), a lncRNA reported to be differentially expressed in hepatocellular carcinoma (HCC). Reverse transcription-quantitative polymerase chain reaction analysis was used to determine the level of Igf2as in HCC cells and tissues. Flow cytometry was used to determine the level of cell apoptosis following Igf2as suppression and western blot analysis was used to identify altered protein expression levels. The results demonstrated that Igf2as was upregulated in HCC cells and tissues, and that the inhibition of Igf2as using a targeted small interfering RNA (si-Igf2as), significantly decreased cell proliferation and increased apoptosis. Western blot analysis identified that the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) signaling pathway was inhibited in cells transfected with si-Igf2as. In addition, cell migration was markedly reduced by the knockdown of Igf2as. These results suggest that lncRNA Igf2as may control hepatocellular progression primarily through the regulation of the ERK/MAPK signaling pathway.

Height, selected genetic markers and prostate cancer risk: results from the PRACTICAL consortium

BACKGROUND

Evidence on height and prostate cancer risk is mixed, however, recent studies with large data sets support a possible role for its association with the risk of aggressive prostate cancer.

METHODS

We analysed data from the PRACTICAL consortium consisting of 6207 prostate cancer cases and 6016 controls and a subset of high grade cases (2480 cases). We explored height, polymorphisms in genes related to growth processes as main effects and their possible interactions.

RESULTS

The results suggest that height is associated with high-grade prostate cancer risk. Men with height >180 cm are at a 22% increased risk as compared to men with height <173 cm (OR 1.22, 95% CI 1.01-1.48). Genetic variants in the growth pathway gene showed an association with prostate cancer risk. The aggregate scores of the selected variants identified a significantly increased risk of overall prostate cancer and high-grade prostate cancer by 13% and 15%, respectively, in the highest score group as compared to lowest score group.

CONCLUSIONS

There was no evidence of gene-environment interaction between height and the selected candidate SNPs.Our findings suggest a role of height in high-grade prostate cancer. The effect of genetic variants in the genes related to growth is seen in all cases and high-grade prostate cancer. There is no interaction between these two exposures.

Weight change, obesity and risk of prostate cancer progression among men with clinically localized prostate cancer

Obesity is associated with an increased risk of fatal prostate cancer. We aimed to elucidate the importance and relevant timing of obesity and weight change for prostate cancer progression. We identified 5,158 men diagnosed with localized prostate cancer (clinical stage T1/T2) from 1986 to 2012 in the Health Professionals Follow-up Study. Men were followed for biochemical recurrence and lethal prostate cancer (development of distant metastasis or prostate cancer-specific mortality) until 2012. Cox regression estimated hazard ratios (HRs) for body mass index (BMI) at age 21, BMI at diagnosis, "long-term" weight change from age 21 to diagnosis and "short-term" weight change over spans of 4 and 8 years preceding diagnosis. Because weight, weight change and mortality are strongly associated with smoking, we repeated analyses among never smokers only (N = 2,559). Among all patients, neither weight change nor BMI (at age 21 or at diagnosis) was associated with lethal prostate cancer. Among never smokers, long-term weight gain was associated with an increased risk of lethal disease (HR for gaining >30 pounds vs. stable weight [±10 pounds] 1.59, 95% CI, 1.01-2.50, p-trend = 0.06). Associations between weight change, BMI and lethal prostate cancer were stronger for men with BMI ≥ 25 at age 21 compared to those with BMI < 25. Weight change and obesity were not associated with an increased risk of biochemical recurrence. Our findings among never smoker men diagnosed with localized prostate cancer suggest a positive association between long-term weight gain and risk of lethal prostate cancer. Metabolic changes associated with weight gain may promote prostate cancer progression.

Isolation and characterization of Pseudomonas aeruginosa PAO mutant that produces altered elastase

Triple-negative breast cancer (TNBC) is cancer that tested as negative for estrogen receptors (ER), progesterone receptors (PR), and excess human epidermal growth factor receptor 2 (HER2) protein which accounts for 15%–20% of all breast cancer cases. TNBC is considered to be a poorer prognosis than other types of breast cancer, mainly because it involves more aggressive phenotypes that are similar to stem cell–like cancer cells (cancer stem cell, CSC). Thus, targeted treatment of TNBC remains a major challenge in clinical practice. This review article surveys the latest evidence concerning the role of genomic alteration in current TNBC treatment responses, current clinical trials and potential targeting sites, CSC and drug resistance, and potential strategies targeting CSCs in TNBC. Furthermore, the role of insulin-like growth factor 1 receptor (IGF-1R) and nicotinic acetylcholine receptors (nAChR) in stemness expression, chemoresistance, and metastasis in TNBC and their relevance to potential treatments are also discussed and highlighted.