Anti‑proliferative effects of in a model for triple negative breast cancer.

Triple negative breast cancer (TNBC) is characterized by the absence of hormones and growth factor receptors. It is typically responsive to anthracycline/taxol-based conventional chemotherapy. However, major therapeutic limitations include systemic toxicity and acquired resistance to chemotherapeutics.

Natural products as drug candidates for breast cancer (Review).

Progression of early-stage breast cancer to advanced-stage metastatic disease represents a major cause of death in women. Long-term conventional and targeted therapy for breast cancer includes multi-drug combinations of cytotoxic chemotherapeutics and pathway-selective small molecule inhibitors. These treatment options are frequently associated with systemic toxicity, intrinsic/acquired therapy resistance and emergence of a drug-resistant cancer stem cell population.

Cancer Cell Models for the Development of Anti-Cancer Drugs.

In the multi-factorial etiology of organ-site cancers by suspect human chemical carcinogens, oncogenic virus, activation of RAS, Myc and HER-2 oncogenes, inactivation of TP53, RB and APC tumor suppressor genes represent early-occurring genetic events [...

Stem Cell Models for Breast and Colon Cancer: Experimental Approach for Drug Discovery.

The progression of the early stages of female breast and colon cancer to metastatic disease represents a major cause of mortality in women. Multi-drug chemotherapy and/or pathway selective targeted therapy are notable for their off-target effects and are associated with spontaneous and/or acquired chemotherapy resistance and the emergence of premalignant chemo-resistant cancer-initiating stem cells. The stem cell populations are responsible for the evolution of therapy-resistant metastatic disease.

The Divergent Effects of Ovarian Steroid Hormones in the MCF-7 Model for Luminal A Breast Cancer: Mechanistic Leads for Therapy.

The growth modulating effects of the ovarian steroid hormones 17β-estradiol (E) and progesterone (PRG) on endocrine-responsive target tissues are well established. In hormone-receptor-positive breast cancer, E functions as a potent growth promoter, while the function of PRG is less defined. In the hormone-receptor-positive Luminal A and Luminal B molecular subtypes of clinical breast cancer, conventional endocrine therapy predominantly targets estrogen receptor function and estrogen biosynthesis and/or growth factor receptors.

Growth Inhibitory Efficacy of Chinese Herbs in a Cellular Model for Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is characterized by the absence of estrogen receptor-α progesterone receptor and human epidermal growth factor receptor-2. Treatment for this breast cancer subtype is restricted to multidrug chemotherapy and survival pathway-based molecularly targeted therapy. The long-term treatment options are associated with systemic toxicity, spontaneous and/or acquired tumor resistance and the emergence a of drug-resistant stem cell population.

Growth inhibitory efficacy of in a cell culture model for triple-negative breast cancer.

Triple-negative breast cancer (TNBC) lacks the expressions of estrogen receptor-α, progesterone receptor and human epidermal growth factor receptor-2. The treatment options for TNBC include anthracyclin/taxol based conventional chemotherapy and small molecular inhibitor based targeted therapy. However, the therapeutic efficacy is limited by systemic toxicity and acquired tumor resistance; identification of less toxic testable alternatives is urgently required.

The nutritional herb inhibits the growth in a model for the Luminal A molecular subtype of breast cancer.

The Luminal A subtype of breast cancer expresses the estrogen receptor (ER)-α and progesterone receptor (PR), but not the human epidermal growth factor receptor (HER)-2 oncogene. This subtype of breast cancer responds to endocrine therapy involving the use of selective estrogen receptor modulators and/or inhibitors of estrogen biosynthesis. However, these therapeutic agents are frequently associated with long-term systemic toxicity and acquired tumor resistance, emphasizing the need to identify non-toxic alternative treatments for chemo-endocrine therapy responsive breast cancer.

Anti-proliferative effects of Chinese herb Cornus officinalis in a cell culture model for estrogen receptor-positive clinical breast cancer.

Selective estrogen receptor modulators and a combination of mechanistically distinct chemotherapeutic agents represent conventional therapeutic interventions for estrogen receptor-positive (ER+) clinical breast cancer. Long-term treatment with these agents is associated with acquired tumor resistance and other adverse side effects that impact on patient compliance. Herbal medicines are being widely used in complementary and alternative medicine.

Lycium barbarum inhibits growth of estrogen receptor positive human breast cancer cells by favorably altering estradiol metabolism.

Selective estrogen receptor modulators represent accepted therapy for estrogen receptor positive (ER+) breast cancer, exhibit adverse side effects, and reduce patient compliance. The use of phytoestrogen containing herbal medicines is limited because of efficacy and safety concerns. The ER+ MCF-7 model examined growth inhibitory effects of the medicinal herb Lycium barbarum (LB) and identified mechanistic leads for its efficacy.

Prevention of early-onset familial/hereditary colon cancer: new models and mechanistic biomarkers (review).

Human colon cancer is a multi-factorial, multi-step disease wherein genetic and dietary factors represent important regulators of initiation, promotion and progression. While the etiology of sporadic colon cancer remains largely unidentified, familial adenomatous polyposis (FAP) and hereditary non-polyposis colon cancer (HNPCC) represent predisposing genetic syndromes for early-onset familial/hereditary colon cancer. These syndromes are characterized by germ-line mutations in the adenomatous polyposis coli (APC) and/or DNA mismatch repair genes, respectively.

Novel cell culture models for prevention of human breast cancer (Review).

Human breast cancer is a multifactorial, multistep disease wherein genetic, endocrine and dietary factors represent crucial regulators of initiation, promotion and progression. Preclinical investigations utilizing human breast carcinoma derived cell lines either in culture, or upon xenotransplantation, have provided valuable leads for molecular pathogenesis of cancer progression and also for novel therapeutic modalities. The mechanistic significance of genetic factors on early events of initiation/promotion, however, is dependent on extrapolation, and is therefore, equivocal.

Soy isoflavone genistein modulates cell cycle progression and induces apoptosis in HER-2/neu oncogene expressing human breast epithelial cells.

In the multistep progressive pathogenesis of human breast cancer, comedo ductal carcinoma in situ (DCIS) represents a preinvasive precursor lesion for therapy resistant invasive cancer. Human tissue derived cell culture models exhibiting molecular similarities to clinical DCIS facilitate an important preclinical mechanistic approach for evaluation of preventive efficacy of natural and synthetic chemopreventive compounds. Natural phytochemicals present in fresh fruits, vegetables and grain products are likely to offer protection against cancer.

Preventive efficacy of receptor class selective retinoids on HER-2/neu oncogene expressing preneoplastic human mammary epithelial cells.

Aberrant proliferation is an early-occurring event in vitro prior to tumorigenesis in vivo in the multistep process of carcinogenesis. Inhibition of aberrant proliferation therefore may represent a useful biomarker to evaluate the efficacy of chemopreventive agents. Retinoids have exhibited preventive efficacy in vitro and in vivo predominantly through the retinoic acid receptors (RARs) and the retinoid X receptors (RXRs).

In Vitro and In Vivo Modulation of Growth Regulation in the Human Breast Cancer Cell Line MCF-7 by Estradiol Metabolites.

BACKGROUND: The natural estrogen 17 beta-estradiol (E2) functions as a potent tumor promoter during tumorigenic transformation of the mammary gland. From amongst the various pathways of E2 metabolism upregulation of C16 alpha-hydroxylation of E2 has been associated with carcinogenesis. In the present study in vitro and in vivo experiments were performed on estrogen receptor positive human breast cancer MCF-7 cells to examine whether the natural estrogen E2 and its metabolites 16 alpha-hydroxyestrone (16 alpha-OHE1) and 2-hydroxyestrone (2-OHE1)function as modulators of tumor cell growth.

Phytochemicals as modulators of cancer risk.

These results, describing antitumor activity of some of the phytochemicals that have been actively studied, suggest that dietary changes could play a role in decreasing the incidence of a variety of tumors. 13C and the other compounds discussed may well be only prototypes for other as yet unexplored phytochemicals present in the diet. There have been no attempts to explore the possibilities of synergistic action among the various phytochemicals, 13C, limonene, curcumin, epigallocatechin gallate, sulforaphene, or genistein.

Multifunctional aspects of the action of indole-3-carbinol as an antitumor agent.

Previous studies from this laboratory have suggested that 2-hydroxyestrone is protective against breast cancer, whereas the other principal metabolite, 16 alpha-hydroxyestrone, and the lesser metabolite quantitatively, 4-hydroxyestrone, are potent carcinogens. Attempts to directly decrease the formation of the 16-hydroxylated metabolite were either unsuccessful or required such high levels of the therapeutic agent as to be impractical. On the other hand the concentration of the protective metabolite, 2-hydroxyestrone, proved to be readily modulated by a variety of agents, both in the direction of increased protection and the opposite direction, increased risk by a variety of agents and activities.

Inhibition of aberrant proliferation and induction of apoptosis in HER-2/neu oncogene transformed human mammary epithelial cells by N-(4-hydroxyphenyl)retinamide.

Epithelial cells from non-cancerous mammary tissue in response to exposure to chemical carcinogens or transfection with oncogenes exhibit hyperproliferation and hyperplasia prior to the development of cancer. Aberrant proliferation may, therefore, represent a modifiable early occurring preneoplastic event that is susceptible to chemoprevention of carcinogenesis. The synthetic retinoid N-(4-hydroxyphenyl)retinamide (HPR), has exhibited preventive efficacy in several in vitro and in vivo breast cancer models, and represents a promising chemopreventive compound for clinical trials.

Alteration of oestradiol metabolism in myc oncogene-transfected mouse mammary epithelial cells.

Targeted overexpression of the c-myc oncogene induces neoplastic transformation in immortalized, non-tumorigenic mouse mammary epithelial cells (MMEC). Experiments in the present study were conducted to examine whether cellular transformation induced by c-myc oncogene is associated with altered metabolism of 17beta-oestradiol (E2). The parental, MMEC and the stable c-myc transfectant (MMEC/myc3) cell lines were compared for major oestrogen metabolic pathways, namely E2 and E1 interconversion, and C2- and C16alpha-hydroxylation by both high-pressure liquid chromatography (HPLC) analysis and the 3H release assay using specifically labelled [C2-3H]E2 or [C16alpha-3H]E2.

Inhibition of aberrant proliferation and induction of apoptosis in pre-neoplastic human mammary epithelial cells by natural phytochemicals.

Aberrant proliferation and modulated apoptosis leading to impaired cellular homeostasis represent crucial early events in the multi-step carcinogenic process. Regulation of these perturbed biomarkers may predict efficacious prevention of cancer development. Present experiments on non-cancerous human mammary epithelial 184-B5 cells were designed to examine whether i) exposure to suspect environmental human carcinogen Benzo (a) pyrene (BP) alters the status of cell proliferation and apoptosis and ii) BP-induced alterations are modulated in response to select natural phytochemicals that inhibit rodent mammary tumorigenesis.

Inhibition of proliferation and modulation of estradiol metabolism: novel mechanisms for breast cancer prevention by the phytochemical indole-3-carbinol.

Aberrant proliferation is an early-occurring intermediate event in carcinogenesis whose inhibition may represent preventive intervention. Indole-3-carbinol (I3C), a glucosinolate metabolite from cruciferous vegetables, inhibits organ site carcinogenesis in rodent models. Clinically relevant biochemical and cellular mechanisms for the anticarcinogenic effects of I3C, however, remain unclear.

Medical hypothesis: bifunctional genetic-hormonal pathways to breast cancer.

As inherited germ line mutations, such as loss of BRCA1 or AT, account for less than 5% of all breast cancer, most cases involve acquired somatic perturbations. Cumulative lifetime exposure to bioavailable estradiol links most known risk factors (except radiation) for breast cancer. Based on a series of recent experimental and epidemiologic findings, we hypothesize that the multistep process of breast carcinogenesis results from exposure to endogenous or exogenous hormones, including phytoestrogens that directly or indirectly alter estrogen metabolism.

Estradiol metabolism: an endocrine biomarker for modulation of human mammary carcinogenesis.

The natural estrogen 17beta-estradiol (E2) has a profound influence on proliferation and neoplastic transformation of mammary epithelium. The role of cellular metabolism of E2 in mammary carcinogenesis, however, remains to be elucidated. Explant culture and cell culture models developed from noncancerous human mammary tissue were used to examine modulation of E2 metabolism in response to treatment with prototype rodent mammary carcinogens and the ability of the naturally occurring phytochemical indole-3-carbinol (13C) to influence E2 metabolism and regulate aberrant proliferation.