Serum insulin-like growth factor (IGF)-1 and IGF-binding protein-3 do not correlate with Gleason score or quantity of prostate cancer in biopsy samples

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.

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 (IGF)-I, IGF binding protein-3, and prostate cancer: correlation with Gleason score

Introduction

Non-androgenic growth factors are involved in the growth regulation of prostate cancer (PCa).

Objective

This is the first Brazilian study to correlate, in a population of patients operated for PCa, PSA, total testosterone, insulin-like growth factor-I (IGF-I) and insulin-like growth factor-binding protein-3 (IGFBP-3) with Gleason score and to compare with a control group with benign prostate hyperplasia (BPH).

Materials and Methods

This retrospective single-center study included 49 men with previously diagnosed PCa and 45 with previously diagnosed BPH. PSA, testosterone, IGF-I, IGFBP-3 were determined in both groups.

Results

PSA and IGFBP-3 levels were significantly higher in the PCa group as compared to the BPH group (p<0.001 and p=0.004, respectively). There was a significant difference when we compared the PSA before surgery (p<0.001) and at the inclusion in the study (p<0.001) and IGFBP3 (0.016) among patients with Gleason <7, ≥7 and BPH. In the PCa group, PSA, testosterone, IGF-I and IGFBP-3 levels were comparable between Gleason <7 and ≥7.

Conclusions

Our data suggest that in localized PCa, the quantification of PSA and, not of IGF-1, may provide independent significant information in the aggressiveness. IGFBP-3 could be a biochemical marker of disease control in PCa patients.

Diverse functions of IGF/insulin signaling in malignant and noncancerous prostate cells: proliferation in cancer cells and differentiation in noncancerous cells

The insulin-like growth factor (IGF) pathway represents one of the most studied molecular regulatory networks in oncology. Clinical trials investigating the therapeutic value of anti-IGF1 receptor (IGF1R) therapies in cancer, including prostate cancer, are ongoing. However, the multiple functions of the IGF network in the prostate are not entirely known. To elucidate the effects of IGF and insulin (INS) on prostate cells, we stimulated prostate cancer (PC3, DU145, LNCaP, DUCaP) and noncancerous prostate cells (EP156T, RWPE-1) and observed differing responses: whereas cancer cells responded to IGF and INS exposure by way of enhanced cell proliferation and glucose consumption, basal to luminal differentiation was induced in noncancerous cells. The same diverse responses were observed when the growth factor receptors IGF1R or INSR were overexpressed. Down-regulation of IGF1R or INSR isoform A (INSRA) also inhibited only proliferation of cancer cells. The proliferative response induced by the INSR in cancer cells was mediated solely by the INSRA. Moreover we observed that the receptors of the IGF network mutually influence their expression and exert redundant functions, thus underscoring the functional molecular network formed by IGF, INS, IGF1R, and INSR. Collectively we found that both IGF1R and INSRA have oncogenic effects in prostate cancer, but the IGF network also has important physiological functions in the noncancerous prostate. These data provide new insights into the biology of the IGF network in the prostate, thereby facilitating the design and interpretation of clinical studies investigating IGF1R targeting agents.

Comparison of chromogranin A, insulin-like growth factor 1 and prostate-specific antigen serum markers in prostate adenocarcinoma and benign prostatic hyperplasia

BACKGROUND/AIM

To compare serum chromogranin A (CgA) and insulin-like growth factor 1 (IGF-1) with the classical prostate-specific antigen (PSA) marker in clinically localized prostate adenocarcinomas.

MATERIALS AND METHODS

This is a prospective single-center study that included 64 consecutive men with newly diagnosed clinically localized prostate adenocarcinoma and 20 consecutive men with histologically confirmed benign prostatic hyperplasia (BPH). A blood sample for the determination of serum total PSA, CgA and IGF-1 levels (RIA) was obtained from all cases. Analysis of variance was performed to evaluate their variations according to disease and the pathological characteristics of prostate adenocarcinoma.

RESULTS

Only serum PSA levels (p < 0.0001) and not IGF-1 (p = 0.5475) or CgA (p = 0.5043) were significantly higher in the prostate cancer (PCa) group as compared to the BPH group. A significant variance between BPH and PCa divided on the basis of pT stage was found for PSA levels (p < 0.0001) but not for CgA (p = 0.0869) and IGF-1 (p = 0.6883) levels. Dividing PCa on the basis of Gleason score, a significant variance was found for CgA (p = 0.0100) and for PSA (p < 0.001), but not for IGF-1 (p = 0.6895) levels.

CONCLUSIONS

In our population the quantification of PSA and CgA serum levels and not of IGF-1 provides independent significant information in the diagnosis and aggressiveness of PCa, respectively.

Serum measurements of testosterone, insulin-like growth factor 1, and insulin-like growth factor binding protein-3 in the diagnosis of prostate cancer among Korean men

AIM

To investigate the relationships of serum testosterone, insulin-like growth factor (IGF)-1 and IGF-binding protein (IGFBP)-3 levels with prostate cancer risk and also with known prognostic parameters of prostate cancer in Korean men who received radical retropubic prostatectomy (RRP) for clinically-localized prostate cancer.

METHODS

Serum levels of total testosterone, free testosterone, IGF-1 and IGFBP-3 were determined in 592 patients who subsequently received prostate biopsy. Results were compared between patients who eventually received RRP for prostate cancer (n=159) and those who were not diagnosed with prostate cancer from biopsy (control group, n=433). Among the prostate cancer only patients, serum hormonal levels obtained were analyzed in relation to serum prostate specific antigen (PSA), pathological T stage and pathological Gleason score.

RESULTS

Prostate cancer patients and the control group demonstrated no significant differences regarding serum levels of total testosterone, free testosterone, IGF-1 and IGFBP-3 across the different age groups. Among the cancer only patients, no significant associations were observed for serum levels of total testosterone, free testosterone, IGF-1 and IGFBP-3 levels with pathological T stage, pathological Gleason score and preoperative PSA.

CONCLUSION

Our data indicate that simple quantifications of serum testosterone and IGF-1 along with IGFBP-3 levels might not provide useful clinical information in the diagnosis of clinically localized prostate cancer in Korean men. Also, our results suggest that serum levels of testosterone, IGF-1 and IGFBP-3 might not be significantly associated with known prognostic factors of clinically localized prostate cancer in Korean men.

Insulin-like growth factors and their binding proteins in prostate cancer: Cause or consequence?☆

Insulin-like growth factors (IGFs) promote growth and survival of many types of tumor cells. Epidemiologic studies have implicated carcinogenesis with high levels of IGFs in circulation or in tissues. The levels of IGF binding proteins (IGFBPs) have been associated with reduced risk for prostate and other cancers. Experimental studies have implicated high levels of IGF-I directly and IGFBP-3 inversely in prostate cancer growth, survival, and progression. However, recent evidence suggests a much weaker association of IGF-I with prostate cancer development and a stronger antagonistic association of IGFBP-3 with prostate cancer progression. Considering the clonal heterogeneity and unpredictable progression pattern of prostate cancer, the role of any single growth factor or its regulator (IGFBP) as a single determining factor is limited. This review is a critical appraisal of the role of IGFs, IGFBP, and IGF-I receptor (the IGF axis) in both experimental and clinical prostate cancer genesis and progression.

Insulin-like growth factor 1, chromogranin A and prostate specific antigen serum levels in prostate cancer patients and controls

OBJECTIVE

Insulin-like growth factor 1 (IGF-1) and chromogranin A (CGA) are currently discussed as supplemental serum markers for prostate cancer (PC) diagnosis. To address this issue we determined serum levels of IGF-1, CGA and PSA in men with newly diagnosed PC and controls.

METHODS

A consecutive series of 156 men (median age: 67 yrs) with newly diagnosed, untreated PC and 271 controls (69 yrs) were recruited. The diagnosis of PC was made by transrectal ultrasound guided biopsies only. In controls, the presence of PC was excluded by digito-rectal examination, serum prostate specific antigen (PSA) levels by using age-specific reference values and-if indicated-by transrectal ultrasound guided 12-core biopsies. Serum levels of IGF-1, CGA and PSA were compared between cases and controls and correlated to histopathological findings and age.

RESULTS

Serum PSA-levels were significantly higher in men with PC (49.6+/-13.9 ng/ml, mean+/-standard error of the mean; median: 7.0 ng/ml) than in controls (2.6+/-0.2 ng/ml; median: 1.3 ng/ml) (p<0.001). In contrast, serum levels of IGF-1 (PC: 166+/-6.1 ng/ml, median: 155 ng/ml; controls: 159+/-4.5 ng/ml, 153 ng/ml) and CGA (PC: 92+/-7.4 U/l, median: 67 U/l; controls: 117+/-12.0 U/l; median: 74 U/l) were identical in both groups (p>0.05). Serum levels of IGF-1 and CGA revealed no correlation to serum PSA, Gleason score and number of positive biopsy cores. In the PC-cohort all three serum markers did not correlate with age. In controls, PSA (p=0.018) and CGA (p<0.001) correlated positively and IGF-1 (p<0.001) negatively with age.

CONCLUSION

Our data suggest that quantification of IGF-1 and CGA-serum levels provides no useful information in the diagnosis of PC.

Circulating free insulin-like growth factor (IGF)-I, total IGF-I, and IGF binding protein-3 levels do not predict the future risk to develop prostate cancer: results of a case-control study involving 201 patients within a population-based screening with a 4-year interval

Recent studies have reported that serum IGF-I levels in the highest quartile of the normal range and IGF binding protein-3 (IGFBP-3) in the lowest quartile of the normal range are associated with an increased risk of future prostate cancer and/or presence of prostate cancer. It has also been suggested that the measurement of circulating total IGF-I concentrations might be a useful tool for the early detection of prostate cancer in men with moderately increased prostate-specific antigen (PSA) levels. To determine whether circulating free IGF-I, total IGF-I, and IGFBP-3 levels can predict future prostate cancer risk, we prospectively studied prostate cancer characteristics in a cohort of men during two rounds (mean interval, 4 yr) of a population-based screening study for prostate cancer. Two hundred one prostate cancer cases were detected at the second-round screening (aged 55-70 yr), and all these subjects were enrolled in the case group for the present study. Prostate cancer had been confirmed by biopsy in all cases. These 201 subjects were matched with the 201 nonprostate cancer cases by age, serum PSA range at the first-round screening (PSA < 2 ng/ml, n = 67; PSA = 2-3 ng/ml, n = 67; and PSA = 3-4 ng/ml, n = 67), and residence area. At baseline, total IGF-I, free IGF-I, and IGFBP-3 levels and prostate volume of cases with prostate cancer were not different from those of healthy controls. PSA velocity was significantly different between cases and controls (P < 0.001).Stepwise forward logistic regression analysis showed that only PSA levels at baseline and PSA at round 2 after 4 yr are good predictors of prostate cancer, whereas total IGF-I, free IGF-I, and IGFBP-3 did not predict the development of prostate cancer. Only one of the 201 subjects with prostate cancer had metastases. Within the subjects with prostate cancer, there were no differences of IGF-I parameters with different tumor node metastasis categories and/or Gleason scores. Our study suggests that the measurement of serum IGF-I and/or IGFBP-3 concentrations in addition to PSA does not improve the identification of men at high risk to develop early stages of prostate cancer. In addition, our results indicate that the endocrine IGF-I system is not directly involved in the growth of the early stages of prostate cancer.