Aromatase Inhibitors in Human Lung Cancer Therapy

Casto

2014

WJCO

145

125

Cohesive scientific evidence from molecular, animal, and human investigations supports the hypothesis that constitutive overexpression of cyclooxygenase-2 (COX-2) is a ubiquitous driver of mammary carcinogenesis, and reciprocally, that COX-2 blockade has strong potential for breast cancer prevention and therapy. Key findings include the following: (1) COX-2 is constitutively expressed throughout breast cancer development and expression intensifies with stage at detection, cancer progression and metastasis; (2) essential features of mammary carcinogenesis (mutagenesis, mitogenesis, angiogenesis, reduced apoptosis, metastasis and immunosuppression) are linked to COX-2-driven prostaglandin E2 (PGE-2) biosynthesis; (3) upregulation of COX-2 and PGE-2 expression induces transcription of CYP-19 and aromatase-catalyzed estrogen biosynthesis which stimulates unbridled mitogenesis; (4) extrahepatic CYP-1B1 in mammary adipose tissue converts paracrine estrogen to carcinogenic quinones with mutagenic impact; and (5) agents that inhibit COX-2 reduce the risk of breast cancer in women without disease and reduce recurrence risk and mortality in women with breast cancer. Recent sharp increases in global breast cancer incidence and mortality are likely driven by chronic inflammation of mammary adipose and upregulation of COX-2 associated with the obesity pandemic. The totality of evidence clearly supports the supposition that mammary carcinogenesis often evolves as a progressive series of highly specific cellular and molecular changes in response to induction of constitutive overexpression of COX-2 and the prostaglandin cascade in the "inflammogenesis of breast cancer". Key words: Breast Cancer; Cyclooxygenase-2; Nonsteroidal anti-inflammatory drugs; Inflammogenesis; Estrogen; Aromatase Core tip: Mammary carcinogenesis often evolves as a series of highly specific cellular and molecular changes in response to induction of constitutive over-expression of cyclooxygenase-2 (COX-2) and the prostaglandin cascade; reciprocally, agents that block COX-2 have significant value in the chemoprevention and therapy of breast cancer.Harris RE, Casto BC, Harris ZM. Cyclooxygenase-2 and the inflammogenesis of breast cancer. World J Clin Oncol 2014; 5(4): 677-692 Available from: URL: http://www.wjgnet.com/2218-4333/full/v5/ i4/677.htm DOI: http://dx.doi.org/10.5306/wjco.v5.i4.677 INTRODUCTIONMore than a century ago, Virchow et al [1,2] chronic inflammation leads to cancer development by increasing cellular proliferation [3] . Various models of carcinogenesis have been proposed involving inflammatory stimuli and mediators of wound healing [4][5][6] . The recent discovery of the inducible cyclooxygenase-2 (COX-2) gene has rekindled interest in the causal link between inflammation and cancer, and various models of carcinogenesis have been proposed involving inflammatory stimuli and COX-2 expression [7][8][9][10] . The current review synthesizes and interprets the accumulating body of evidence supporting COX-2 driven inflammogenesis as a ge...

Section: Mitogenesismentioning

confidence: 99%

Cyclooxygenase-2 and the inflammogenesis of breast cancer

Casto

2014

WJCO

145

125

The Journal of Steroid Biochemistry and Molecular Biology

“…The enzyme aromatase (cytochrome P450 (CYP)19), an important regulator of estrogen hormone availability, has become a target for new drug synthesis of inhibitors attempting to treat estrogen hormone-dependent cancers, which in addition to breast cancer [1] now also includes lung cancer [2].…”

Section: Introductionmentioning

confidence: 99%

Aromatase inhibition by bioavailable methylated flavones

Ta¹,

Walle²

2007

Previous studies have shown chrysin, 7-hydroxyflavone and 7,4′-dihydroxyflavone to be the most potent flavonoid inhibitors of aromatase. However, very poor oral bioavailability is a major limitation for the successful use of dietary flavonoids as chemopreventive agents. We have recently shown that methylated flavones, including 5,7-dimethoxyflavone, 7-methoxyflavone and 7,4′-dimethoxyflavone, are much more resistant to metabolism than their unmethylated analogs and have much higher intestinal absorption. In this study, we examined these fully methylated flavones as potential aromatase inhibitors for the prevention and/or treatment of hormone-dependent cancers. Whereas 5,7-dimethoxyflavone had poor effect compared to its unmethylated analog chrysin, 7-methoxyflavone and 7,4′-dimethoxyflavone were almost equipotent to their unmethylated analogs with IC 50 values of 2 to 9 μM. Thus, some fully methylated flavones appear to have great potential as cancer chemopreventive/chemotherapeutic agents.

“…These results are similar to those described in non-small cell lung cancer where anastrozole significantly reduced cell viability. Interestingly, an aromatase enzyme activity decrease occurred [5].…”

Section: Discussionmentioning

confidence: 98%

“…It has been described that estrogens play an important role in in vitro and in vivo models of cancer proliferation. Indeed, several types of tumors synthesize estrogens and express estrogen receptors having a fundamental role in the growth of breast, endometrium, lung and prostate cancer [5,14,15]. Therefore, medication inhibiting estrogen synthesis or regulating estrogen receptor expression is an alternative for cancer therapy.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Anastrozole Reduce Cell Proliferation and Induce Apoptosis in Glioblastoma Multiforme Xenograft Mouse Model

García¹,

Ramirez²,

Jiménez³

et al. 2017

J Cancer Sci Ther

Objective: Glioblastoma multiforme is the most aggressive form of primary brain tumors, characterized by a high molecular heterogeneity hinder its treatment. Glioblastoma multiforme cells synthesize steroids through the enzyme aromatase and express estrogen receptors. Anastrozole, a specific aromatase inhibitor, plays an important role in endocrine therapy for breast cancer treatment. However, it is unknown whether this inhibitor is useful for treating glioblastoma multiforme. The aim of this work was evaluated the anastrozole effects in the viability and proliferation of malignant cells C6 in vitro as well as apoptosis, cell division, aromatase and estrogen receptor alpha expression in a GBM model in vivo.Methods: C6 cells viability under anastrozole treatment (25, 50, 75 µg/ml) was measured by MTT method and their proliferation was determinate by immunohitofluorescence. In the tumor tissue, the proliferation was evaluated using ki-67 antibody by immunohistofluorescence. ER alpha, aromatase, caspase 8 and 9 protein expression was analyzed using western-blotting. Furthermore, GPR-30, SOX2, CD133 and GFAP were evaluated by immunohistofluorescence.Results: Anastrozole produced a reduction in the viability and proliferation of the C6 cells in culture when was used at 50 μg/ml. It reduces the number of Ki67 immunofluorescent cells in approximately 50%. The aromatase expression decreased in 95%. The estrogen receptor alpha expression increased by a 20% approximately. Caspase 8 expression increased in the treated tumor tissue, although it was undetectable in the not treated group. Caspase 9 increased in approximately 95% in the treated group. All data expressed in these experimental quantifications have a statistically significant difference (p<0.05). G protein coupled receptor-30 was observed in the tumor specimens exhibiting an expression reduction in the anastrozole treated group. Conclusion:The present study demonstrates that anastrozole reduces viability and proliferation in vitro, induces apoptosis and reduces proliferation and aromatase expression in the glioblastoma Xenograft mouse model.