Insulin and glucose status, tissue and plasma lipids in patients with tumours of the ovary or endometrium: possible dietary implications

LDL, HDL and endocrine-related cancer: From pathogenic mechanisms to therapies

Cholesterol is essential for a variety of functions in endocrine-related cells, including hormone and steroid production. We have reviewed the progress to date in research on the role of the main cholesterol-containing lipoproteins; low-density lipoprotein (LDL) and high-density lipoprotein (HDL), and their impact on intracellular cholesterol homeostasis and carcinogenic pathways in endocrine-related cancers. Neither LDL-cholesterol (LDL-C) nor HDL-cholesterol (HDL-C) was consistently associated with endocrine-related cancer risk. However, preclinical studies showed that LDL receptor plays a critical role in endocrine-related tumor cells, mainly by enhancing circulating LDL-C uptake and modulating tumorigenic signaling pathways. Although scavenger receptor type BI-mediated uptake of HDL could enhance cell proliferation in breast, prostate, and ovarian cancer, these effects may be counteracted by the antioxidant and anti-inflammatory properties of HDL. Moreover, 27-hydroxycholesterol a metabolite of cholesterol promotes tumorigenic processes in breast and epithelial thyroid cancer. Furthermore, statins have been reported to reduce the incidence of breast, prostate, pancreatic, and ovarian cancer in large clinical trials, in part because of their ability to lower cholesterol synthesis. Overall, cholesterol homeostasis deregulation in endocrine-related cancers offers new therapeutic opportunities, but more mechanistic studies are needed to translate the preclinical findings into clinical therapies.

Lipid profile and risk of ovarian tumours: a meta-analysis

BACKGROUND

Existing data from several reports on the association between lipid profile and ovarian tumour (OT) suggests divergent conclusions. Our aim was to examine whether circulating lipid profile: total cholesterol (TC), triglyceride (TG), high-density lipoprotein (HDL) and low-density lipoprotein (LDL) differed between cases and non-cases of OT.

METHODS

Electronic repositories; PUBMED, EMBASE and Cochrane library were explored through December 2019 to retrieve published articles for inclusion in the meta-analysis after quality assessment. Heterogeneity was assessed using I2 statistics, the effect of individual studies on the overall effect size was tested using sensitivity analysis and funnel plot was used to evaluate publication bias.

RESULTS

Twelve studies, involving 1767 OT cases and 229,167 non-cases of OT were included in this meta-analysis and I2 statistics ranged between 97 and 99%. Mean circulating TC (- 16.60 [- 32.43, - 0.77]mg/dL; P = 0.04) and HDL (- 0.25[- 0.43, - 0.08]mmol/L; P = 0.005) were significantly lower among OT cases compared to non-OT cases.

CONCLUSION

Decreased TC and HDL profiles were observed among subjects with OT in this collection of reports. The implications of TC and HDL in tumour manifestations and growth need to be validated in a large multi-ethnic longitudinal cohort adjusting for relevant confounders.

Development of a multimarker assay for early detection of ovarian cancer

PURPOSE

Early detection of ovarian cancer has great promise to improve clinical outcome.

PATIENTS AND METHODS

Ninety-six serum biomarkers were analyzed in sera from healthy women and from patients with ovarian cancer, benign pelvic tumors, and breast, colorectal, and lung cancers, using multiplex xMAP bead-based immunoassays. A Metropolis algorithm with Monte Carlo simulation (MMC) was used for analysis of the data.

RESULTS

A training set, including sera from 139 patients with early-stage ovarian cancer, 149 patients with late-stage ovarian cancer, and 1,102 healthy women, was analyzed with MMC algorithm and cross validation to identify an optimal biomarker panel discriminating early-stage cancer from healthy controls. The four-biomarker panel providing the highest diagnostic power of 86% sensitivity (SN) for early-stage and 93% SN for late-stage ovarian cancer at 98% specificity (SP) was comprised of CA-125, HE4, CEA, and VCAM-1. This model was applied to an independent blinded validation set consisting of sera from 44 patients with early-stage ovarian cancer, 124 patients with late-stage ovarian cancer, and 929 healthy women, providing unbiased estimates of 86% SN for stage I and II and 95% SN for stage III and IV disease at 98% SP. This panel was selective for ovarian cancer showing SN of 33% for benign pelvic disease, SN of 6% for breast cancer, SN of 0% for colorectal cancer, and SN of 36% for lung cancer.

CONCLUSION

A panel of CA-125, HE4, CEA, and VCAM-1, after additional validation, could serve as an initial stage in a screening strategy for epithelial ovarian cancer.

Molecular characterization of lung dysplasia induced by c-Raf-1

Background

Lung cancer is a multistage process with poor prognosis and high morbidity. Importantly, the genetics of dysplasia, a facultative cancer, at the edge of malignant transformation is unknown.

Methodology/Principal Findings

We employed laser microdissection to harvest c-Raf1- induced dysplastic as opposed to transgenic but otherwise morphologically unaltered epithelium and compared findings to non-transgenic lung. We then employed microarrays to search genome wide for gene regulatory networks. A total of 120 and 287 genes were significantly regulated, respectively. Dysplasia was exclusive associated with up-regulation of genes coding for cell growth and proliferation, cell-to-cell signalling and interaction, lipid metabolism, development, and cancer. Likewise, when dysplasia was compared with non-transgenic cells up-regulation of cancer associated genes, tight junction proteins, xenobiotic defence and developmental regulators was observed. Further, in a comparison of the data sets of dysplasia vs transgenic and dysplasia vs non-transgenic 114 genes were regulated in common. We additionally confirmed regulation of some genes by immunohistochemistry and therefore demonstrate good concordance between gene regulation and coded protein.

Conclusion

Our study identified transcriptional networks at successive stages of tumor-development, i.e. from histological unaltered but transgenic lungs to nuclear atypia. Our SP-C/c-raf transgenic mouse model revealed interesting and novel candidate genes and pathways that provide clues on the mechanism forcing respiratory epithelium into dysplasia and subsequently cancer, some of which might also be useful in the molecular imaging and flagging of early stages of disease.

Cancer cachexia

CAUSATIVE FACTORS: Nutritional supplementation or pharmacological manipulation of appetite are unable to control the muscle atrophy seen in cancer cachexia. This suggests that tumour and/or host factors might be responsible for the depression in protein synthesis and the increase in protein degradation. An increased expression of the ubiquitin-proteasome proteolytic pathway is responsible for the increased degradation of myofibrillar proteins in skeletal muscle, and this may be due to tumour factors, such as proteolysis-inducing factor (PIF), or host factors such as tumour necrosis factor-alpha (TNF-alpha). In humans loss of adipose tissue is due to an increase in lipolysis rather than a decrease in synthesis, and this may be due to tumour factors such as lipid-mobilising factor (LMF) or TNF-alpha, both of which can increase cyclic AMP in adipocytes, leading to activation of hormone-sensitive lipase (HSL). Levels of mRNA for HSL are elevated twofold in adipose tissue of cancer patients, while there are no changes in lipoprotein lipase (LPL), involved in extraction of fatty acids from plasma lipoproteins for storage. TREATMENT FOR CACHEXIA: This has concentrated on increasing food intake, although that alone is unable to reverse the metabolic changes. Agents interfering with TNF-alpha have not been very successful to date, although more research is required in that area. The only agent tested clinically that is able to interfere with the action of PIF is eicosapentaenoic acid (EPA). EPA attenuates protein degradation in skeletal muscle by preventing the increased expression of the ubiquitin-proteasome pathway, but has no effect on protein synthesis. When used alone EPA prevents further wasting in cachectic patients, and, when it is combined with an energy- and protein-dense nutritional supplement, weight gain is seen, which is totally lean body mass. These results suggest that mechanistic studies into the causes of cancer cachexia will allow appropriate therapeutic intervention.

Treatment of atypical endometrial hyperplasia with an insulin-sensitizing agent

Endometrial cancer and hyperplasia have long been associated with diabetes. Hyperinsulinemia may have a direct mitogenic effect on the endometrium and may inhibit the effect of progestogen therapy. This case report describes the treatment of a patient with atypical endometrial hyperplasia with an insulin-sensitizing agent. A 37-year-old patient presented after failed treatment of endometrial hyperplasia with progestogen therapy. One month after initiating metformin therapy the patient's endometrial biopsy demonstrated proliferative endometrium. This patient's atypical endometrial hyperplasia regressed after the initiation of treatment with an insulin-sensitizing agent. This relatively new class of drugs may provide an adjunct to the therapy of endometrial hyperplasia.

Biology of cachexia

About half of all cancer patients show a syndrome of cachexia, characterized by loss of adipose tissue and skeletal muscle mass. Such patients have a decreased survival time, compared with the survival time among patients without weight loss, and loss of total body protein leads to substantial impairment of respiratory muscle function. These changes cannot be fully explained by the accompanying anorexia, and nutritional supplementation alone is unable to reverse the wasting process. Despite a falling caloric intake, patients with cachexia frequently show an elevated resting energy expenditure as a result of increases in Cori cycle (i.e., catalytic conversion of lactic acid to glucose) activity, glucose and triglyceride-fatty acid cycling, and gluconeogenesis. A number of cytokines, including tumor necrosis factor-apha, interleukins 1 and 6, interferon gamma, and leukemia-inhibitory factor, have been proposed as mediators of the cachectic process. However, the results of a number of clinical and laboratory studies suggest that the action of the cytokines alone is unable to explain the complex mechanism of wasting in cancer cachexia. In addition, cachexia has been observed in some xenograft models even without a cytokine involvement, suggesting that other factors may be involved. These probably include catabolic factors, which act directly on skeletal muscle and adipose tissue and the presence of which has been associated with the clinical development of cachexia. A polyunsaturated fatty acid, eicosapentaenoic acid, attenuates the action of such catabolic factors and has been shown to stabilize the process of wasting and resting energy expenditure in patients with pancreatic cancer. Such a pharmacologic approach may provide new insights into the treatment of cachexia.

Subcutaneous, omentum and tumor fatty acid composition, and serum insulin status in patients with benign or cancerous ovarian or endometrial tumors. Do tumors preferentially utilize polyunsaturated fatty acids?

The relationships between the fatty acid composition of cancerous endometrium and ovary, and peripheral adipose tissues were studied in Israeli Jewish women, and are presented together since no differences were shown between them. The results suggest a mobilization of linoleic acid from subcutaneous and omental depots and its incorporation into tumors accompanied by a high degree of desaturation. High blood insulin concentrations characterized patients with stage I and II disease, and low concentrations characterized patients with advanced degrees of malignancy.

Breast cancer: further metabolic-endocrine risk markers?

There is evidence that increased oestrogen receptor (ER) expression in normal mammary epithelium may be a risk marker for the development of breast cancer. Insulin-like growth factor 1 (IGF1) is a potent inducer of mitosis and has been shown to synergize with oestrogen in stimulating the growth of human breast cancer in vitro. In these cells oestradiol has been shown to upregulate IGF type 1 receptor (IGFR), and recently a similar effect has been reported in normal human breast tissue xenografts in vivo. It has been postulated that the combined effect of oestradiol and IGF1 may stimulate proliferation in normal mammary epithelium and increase breast cancer risk. The bioavailability of IGF1 to the tissues is modulated by IGF-binding proteins (IGFBPs), and higher circulating levels of IGF1 and lower levels of IGFBP3 have been reported in breast cancer patients. Breast cancer specimens show a positive correlation between ER status and IGF receptor status, and also a negative correlation between ER status and IGFBP3 expression. Finally, ectopic growth hormone expression has been shown in a majority of specimens of normal and malignant breast tissue, and this may contribute to breast cancer risk, possibly by increasing the local level of bioavailable IGF1. Expansion of such findings may provide clinically useful markers of increased risk to breast cancer in women.

Hyperinsulinemia in colon, stomach and breast cancer patients

The objective of this study was to collect more information on the intricate relationship between the presence of a tumor, insulin status and blood lipids. We selected non-obese subjects suffering from colon, stomach and breast cancer and determined the concentration of fasting insulin, glucose, cholesterol, and triglycerides in blood before (BS) and after surgery (AS). Controls were healthy non-obese subjects. Insulin was also measured in tumors and non-cancerous tissues from the same organ. BS insulin and glucose (with the exception of glucose in colon patients) were significantly higher than the controls and fell to almost normal levels at AS. Serum cholesterol and triglycerides levels were reduced in stomach patients, BS and AS and cholesterol in colon patients BS. Tumors had 1.9-3.0 times as much insulin, or insulin-like substances, as control tissues. These results are consistent with our previous studies showing hyperinsulinemia in the presence of a tumor.