Role of Endocrine-Genotoxic Switchings in Cancer and Other Human Diseases:

Cancer endocrinology through own experience: areas for further thought and development. Interview by Natasha Galukande

Lev Berstein speaks to Natasha Galukande, Assistant Commissioning Editor. Lev Berstein is Chief of Laboratory of Oncoendocrinology at the Petrov Research Institute of Oncology, St Petersburg, Russia. His main scientific interests include mechanisms of hormonal carcinogenesis, studying risk factors of hormone-associated tumors, and new approaches for prevention and treatment of the latter. As a clinician, he is involved in the management of cancer patients needing hormonal therapy or having endocrine pathology. Berstein has received several international distinctions (including an INTAS grant and UICC Translational Cancer Research Fellowship), serves as a Member of Council of the Russian Endocrine Association and is on the editorial boards of several international journals, including Future Oncology, was Guest Editor for a special focus issue of Expert Review of Endocrinology and Metabolism on hormones in breast and prostate cancer, and is a member of the European Association of Cancer Research and The Endocrine Society of the USA. His bibliography includes 11 monographs, 21 chapters and more than 200 papers in peer-reviewed journals. He graduated as a MD from Tartu University in Estonia and completed his PhD and Doctor of Medical Sciences degrees in cancer endocrinology at the NN Petrov Institute in St Petersburg (Russia).

Cancer and heterogeneity of obesity: a potential contribution of brown fat

Obesity has lately been drawing additional attention as a potential cancer risk and, with some exceptions as a prognostic factor. As obesity is a complex issue characterized by different variants, mechanisms and manifestations, its role in cancer development is also a complex problem exceeding the basic fact of the fat content rising above certain limits. Therefore, in the present paper obesity is viewed as a heterogeneous entity, which has distinct connections with cancer pathogenesis. Among other issues, emphasis is made on the state of white and brown adipose tissue, in particular the association of specific brown fat features and the so-called white fat browning with the functions of normal and mutated tumor suppressor genes, such as PTEN and BRCA1. These connections are considered from the viewpoint implying the existence of two types of hormonal carcinogenesis and of hormonal mediation of the genetic predisposition to tumor development, and should be accounted for in prevention and treatment of both obesity and cancer.

Hepatocellular proliferation and hepatocarcinogen bioactivation in mice with diet-induced fatty liver and obesity

Human liver cancer is in part associated with obesity and related metabolic diseases. The present study was undertaken in a mouse model of diet-induced obesity (DIO) and hepatic steatosis, conditions which can be associated with hepatic neoplasia, to determine whether the rates of cell proliferation or hepatocarcinogen bioactivation were altered in ways which could facilitate hepatocarcinogenesis. DIO mice were generated by feeding C57BL/6 (B6) male mice a high-fat diet beginning at 4 weeks of age; age-matched conventional lean (LEAN) B6 mice fed a low fat diet (10% Kcal from fat) were used for comparison. Groups of 28 week old DIO and LEAN mice were dosed with the bioactivation-dependent DNA-reactive hepatocarcinogen 2-acetylaminofluorene (AAF), at 2.24 or 22.4 mg/kg, given by gavage 3 times per week for 31 days, or received no treatment (DIO and LEAN control groups). Compared with the LEAN control group, the DIO control group had a higher mean body weight (16.5 g), higher mean absolute (1.4 g) and mean relative (25.5%) liver weights, higher (394%) liver triglyceride concentrations, and an increased incidence and severity of hepatocellular steatosis at the end of the dosing phase. The DIO control group also had a higher mean hepatocellular replicating fraction (31% increase, determined by proliferating cell nuclear antigen immunohistochemistry). Hepatocarcinogen bioactivation, based on formation of AAF DNA adducts as measured by nucleotide (32)P-postlabeling, was similar in both DIO and LEAN AAF-dosed groups. Thus, hepatocellular proliferation, but not hepatocarcinogen bioactivation, was identified as an alteration in livers of DIO mice which could contribute to their susceptibility to hepatocarcinogenesis.

Modern approach to metabolic rehabilitation of cancer patients: biguanides (phenformin and metformin) and beyond

Comparing the experience accumulated for more than 40 years in the Laboratory of Endocrinology of Petrov Institute of Oncology (St Petersburg, Russia) with similar approaches practiced elsewhere, evidence supports the reasonability of metabolic rehabilitation of patients suffering from breast cancer or other hormone-dependent malignancies. The primary objective of such approaches is to improve treatment results by ameliorating hormonal-metabolic disturbances, including excess body fat, glucose intolerance, insulin resistance and manifestations of endocrine-genotoxic switchings, and modify tissue and cellular targets or mechanisms related or nondirectly related to the aforementioned disturbances. The relevant measures may be categorized as pharmacological (antidiabetic biguanides exemplified with metformin being most popular but not exclusive) and nonpharmacological (rational nutrition, moderate physical activity and so forth) and used separately or in different combinations.

Endocrinology of the wild and mutant BRCA1 gene and types of hormonal carcinogenesis

Information related to the BRCA1 gene has increasingly become a subject for analysis by endocrinologists. For example, it is hard to dismiss the fact that, in BRCA1 mutation carriers, tumors develop predominantly in such estrogen-dependent organs as the mammary glands and ovaries but not in the endometrium. Another characteristic feature is that although BRCA1 mutants and knock-downs are unable to inhibit the transcriptional activity of estrogen receptor-alpha, in BRCA1 mutation carriers breast cancers are often estrogen receptor-negative and originate from the basal rather than the luminal epithelium. The latter, together with other data, suggests that BRCA1-positive breast neoplasms could be considered to be a consequence of the genotoxic variant of hormonal carcinogenesis (that is, associated with DNA damaging rather then with pure hormonal/physiological properties of hormones or their derivatives). Of indisputable significance are the data demonstrating that knocking down of the BRCA1 gene is accompanied by aromatase overexpression and the abolishment of IGF-1 receptor expression suppression, thus increasing both steroid and insulin signaling. Importantly, the endocrine-genotoxic 'liberation' found upon transfer from the wild-type to the mutant BRCA1 provides grounds to regard BRCA1 as a modulator of endocrine-genotoxic switching (predominantly into a direction of DNA-damaging hormone effects) and also to ask whether this is a property of only this or some other tumor suppressor's.