Impact of metabolic disorders on prostate cancer growth: Androgen and insulin resistance perspectives

Glycemic control was associated with nonprostate cancer and overall mortalities in diabetic patients with prostate cancer

BACKGROUND

Diabetes mellitus (DM) can worsen the prognosis or survival in prostate cancer (PC) patients. We investigated whether glycemic control impacts mortality in PC patients with existing diabetes.

METHODS

All PC patients with or without preexisting DM were enrolled from 2006 to 2017. Mean hemoglobin A1c (HbA1c) values (<7%, 7%-9%, ≥9%) were used to represent glycemic control. Major outcomes included all-cause, PC-specific, and non-PC mortalities. Statistical analyses were performed using Cox regression models with adjusted mean HbA1c and other related confounders.

RESULTS

A total of 831 PC patients were enrolled (non-DM group, n = 690; DM group with a record of mean HbA1c values, n = 141). Results showed that the DM group with mean HbA1c level ≥ 9% (n = 14) had significantly increased risk for all-cause and non-PC mortality (hazard ratio [HR], 3.09; 95% CIs, 1.15-8.32; p=0.025 and HR, 5.49; 95% CIs, 1.66-18.16; p = 0.005, respectively), but not for PC-specific mortality (HR, 1.03; 95% CIs, 0.13-8.44; p = 0.975), compared with the non-DM group.

CONCLUSION

Our findings indicate that PC patients with DM who had a mean HbA1c level ≥ 9% had higher risks of all-cause and non-PC mortality compared with non-DM subjects. Further large and long-term studies are needed to verify the effect of glycemic control in PC patients with DM.

High aldehyde dehydrogenase 1 activity is related to radiation resistance due to activation of AKT signaling after insulin stimulation in prostate cancer

The association between type 2 diabetes mellitus and prostate cancer is still under investigation, and the relationship between hyperinsulinemia and prostate cancer stem-like cells (CSCs) is elusive. Here, we investigated the function of insulin/AKT signaling in prostate CSCs. We isolated prostate CSCs as aldehyde dehydrogenase 1-high (ALDH1^high) cells from the human prostate cancer 22Rv1 cell line using an ALDEFLUOR assay and established several ALDH1^high and ALDH1^low clones. ALDH1^high clones showed high ALDH1 expression which is a putative CSC marker; however, they showed heterogeneity regarding tumorigenicity and resistance to radiation and chemotherapy. Interestingly, all ALDH1^high clones showed lower phosphorylated AKT (Ser473) (pAKT) levels than the ALDH1^low clones. PI3K/AKT signaling is a key cell survival pathway and we analyzed radiation resistance under AKT signaling activation by insulin. Insulin increased pAKT levels in ALDH1^high and ALDH1^low cells; the fold increase rate of pAKT was higher in ALDH1^high cells than in ALDH1^low cells. Insulin induced resistance to radiation and chemotherapy in ALDH1^high cells, and the increased levels of pAKT induced by insulin were significantly related to radiation resistance. These results suggest that ALDH1 suppresses baseline pAKT levels, but AKT can be activated by insulin, leading to treatment resistance.

Growth Hormone/Insulin Growth Factor Axis in Sex Steroid Associated Disorders and Related Cancers

To date, almost all solid malignancies have implicated insulin-like growth factor (IGF) signalling as a driver of tumour growth. However, the remarkable level of crosstalk between sex hormones, the IGF-1 receptor (IGF-1R) and its ligands IGF-1 and 2 in endocrine driven cancers is incompletely understood. Similar to the sex steroids, IGF signalling is essential in normal development as well as growth and tissue homoeostasis, and undergoes a steady decline with advancing age and increasing visceral adiposity. Interestingly, IGF-1 has been found to play a compensatory role for both estrogen receptor (ER) and androgen receptor (AR) by augmenting hormonal responses in the absence of, or where low levels of ligand are present. Furthermore, experimental, and epidemiological evidence supports a role for dysregulated IGF signalling in breast and prostate cancers. Insulin-like growth factor binding protein (IGFBP) molecules can regulate the bioavailability of IGF-1 and are frequently expressed in these hormonally regulated tissues. The link between age-related disease and the role of IGF-1 in the process of ageing and longevity has gained much attention over the last few decades, spurring the development of numerous IGF targeted therapies that have, to date, failed to deliver on their therapeutic potential. This review will provide an overview of the sexually dimorphic nature of IGF signalling in humans and how this is impacted by the reduction in sex steroids in mid-life. It will also explore the latest links with metabolic syndromes, hormonal imbalances associated with ageing and targeting of IGF signalling in endocrine-related tumour growth with an emphasis on post-menopausal breast cancer and the impact of the steroidal milieu.

Serum lipids might improve prostate-specific antigen sensitivity in patients undergoing transrectal ultrasonography-guided biopsy for suspected prostate cancer: A pilot study

Objectives: To investigate the potential use of body mass index (BMI) and serum lipids in improving prostate-specific antigen (PSA) sensitivity in patients undergoing biopsy for suspicion of prostate cancer, as there is an established relationship between metabolic syndrome, obesity and serum lipids with prostate cancer.

Patients and methods: A pilot study was conducted in a tertiary referral centre between June 2016 and August 2017 of patients undergoing transrectal ultrasonography (TRUS)-guided biopsy. After the result of TRUS-biopsy, the first 50 patients diagnosed with prostate cancer (study group) and those with no prostate cancer (control group) were enrolled. BMI, serum PSA level, fasting blood sugar and lipid profile (e.g. cholesterol, triglycerides, low-density lipoprotein [LDL] and high-density lipoprotein [HDL]), were compared between the groups.

Results: Higher BMI, cholesterol, LDL and lower HDL together with PSA were significantly associated with a positive biopsy. On multivariate analysis, LDL (odds ratio [OR] 5.3, 95% confidence interval [CI] 1.2–24.9; P = 0.03) and total PSA level (OR 12.9, 95% CI 4.7–35; P < 0.001) were independent predictors of a positive biopsy. A combination of LDL <80 mg/dL and PSA level <26 ng/mL threshold values determined by receiver operating characteristic curve analysis, had a sensitivity and specificity of 94% and 28%, respectively; whilst, the negative (NPV) and positive predictive values were 82.4% and 56.6%, respectively. The sensitivity and NPV of the combination was significantly higher than that of PSA level alone (94% vs 72% and 82.4% vs 75%, respectively; P < 0.001).

Conclusions: Serum lipids might have a role in the diagnosis of prostate cancer and could be used as an adjunct to PSA measurement to improve sensitivity and avoid unnecessary biopsies.

Abbreviations: AUC: area under the curve; BMI: body mass index; FBS: fasting blood sugar; HDL: high-density lipoprotein; LDL: low-density lipoprotein; LOX-1: lectin-like oxidised LDL receptor-1; OR: odds ratio; ROC: receiver operating characteristic; RP: radical prostatectomy; TG: triglyceride

Dietary inflammatory index is associated with increased risk for prostate cancer among Vietnamese men

OBJECTIVE

Inflammatory potential of diet, as measured by the dietary inflammatory index (DII), has consistently been associated with an increased risk for prostate cancer (PCa). However, data has largely been reported in populations with more proinflammatory dietary patterns, whereas there is high diversity in dietary pattern worldwide. The aim of this study was to assess the association between DII scores and the risk for PCa in Vietnam.

METHODS

A case-control study of 652 participants (244 incident PCa patients, 64-75 y of age, and 408 controls, frequency matched for age) was conducted in Ho Chi Minh City, Vietnam, from 2013 to 2015. Habitual diet was ascertained using a validated food frequency questionnaire (FFQ), whereas other factors, including demographic and lifestyle characteristics, were assessed via face-to-face interviews. The daily intake of pro- and anti-inflammatory nutrients for each participant was calculated from the FFQ and used to estimate individuals' energy-adjusted DII (E-DII) scores. Multivariate-adjusted odds ratios (OR) and 95% confidence intervals (CIs) were estimated using unconditional logistic regression models.

RESULTS

Comparing the middle and highest versus lowest tertile of DII scores, there was an increased risk for overall PCa. The OR and associated 95% CI was 2.63 (1.61-4.37) and 3.35 (2.06-5.53), respectively (P_trend < 0.01). Similar results were found for low-moderate and high-grade PCa. The respective ORs (95% CI) were 3.34 (1.66-7.13) and 5.29 (2.69-11.18), P_trend < 0.001, and 2.51 (1.40-4.63) and 2.57 (1.43-4.73), P_trend 0.006.

CONCLUSION

A proinflammatory diet was associated with increased risk for PCa among Vietnamese men.

Frailty in elderly diabetes patients

Frailty is a state of vulnerability and a consequence of cumulative decline in multiple physiological systems over a lifespan. The occurrence of frailty depends on deterioration in muscle and nerve function, declining cardiopulmonary reserve and loss of executive function. Diabetes mellitus (DM) often causes functional impairment in each of the above systems, thus leading to a loss of whole body homeostasis and deterioration in physical function. Inability of self-management in DM patients may also have considerable impact on the development of sarcopenia/frailty. Thus, there may be positive feedback between the progression of diabetic complications and frailty/sarcopenia. While various factors are involved in this process, insulin resistance or insulin depletion may be an important factor in the progression of frailty in diabetes patients since insulin is well known to be an anabolic hormone in muscle. Interestingly, in our study targeting elderly DM patients, low HbA1c was a significant and independent risk factor for frailty, as assessed using a broad sense frailty scale, the Clinical Frailty Scale (CSF), suggesting that reverse metabolism due to malnutrition in elderly type 2 DM patients might be involved. Therefore, an intervention that includes proper nutrition and exercise training may be essential for the prevention of frailty. The pathogenesis of frailty in DM patients is extensively discussed in this review.

Impact of metabolic disorders on prostate cancer growth: Androgen and insulin resistance perspectives

Background

A high prevalence of cancers in metabolic disorders, like metabolic syndrome (MetS) and type 2 diabetes mellitus (T2DM), recently has been noted, including prostate cancer (PC), which is androgen-sensitive. However, the pathological relationship among testosterone and insulin and insulin-like growth factor (IGF)-1 signaling in relation to MetS and T2DM with PC remains unclear.

Methods

Papers were reviewed, including those by the authors.

Results

In MetS or the initial stage of T2DM accompanying insulin resistance, insulin and IGF-1 signaling could be essential for PC growth. In the advanced stage of T2DM, the decrease in insulin secretion might work against PC growth. A decrease in testosterone concentration with T2DM also might suppress PC proliferation. Androgen deprivation therapy in patients with PC might increase the risk of MetS and/or T2DM and consequently cardiovascular events. Certain drugs for T2DM treatment, such as metformin and glucagon-like peptide-1 analog, potentially might be useful for the treatment of PC.

Conclusion

The improvement of insulin resistance appears to be essential for the prevention of PC growth. Further studies are needed to clarify the complicated pathophysiology of metabolic disorders in PC growth.