Publications by authors named "Ezequiel M Rivero"

Article Synopsis
  • Breast cancer is the most common cancer in women, classified into types based on hormone receptor expression and HER2 overexpression—specifically luminal, HER2+, and triple-negative subtypes.
  • Stress from cancer diagnosis and treatment activates the "fight-or-flight" response through catecholamines, particularly affecting breast cancer progression via β2 and α2 adrenergic receptors.
  • β2 receptors may inhibit cancer growth and metastasis, while α2B and α2C receptors may promote proliferation; this suggests potential for repurposing certain adrenergic drugs as breast cancer treatments due to their minimal side effects.
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The β-blocker propranolol (PROP) has been proposed as a repurposed treatment for breast cancer. The similarity of action between β-agonists and antagonists found on breast cells encouraged us to compare PROP and isoproterenol (ISO, agonist) signaling pathways on a human breast cell line. Cell proliferation was measured by cell counting and DNA-synthesis.

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Aims: Breast cancer is the most frequently diagnosed and leading cause of cancer death among women worldwide. It was classified within molecular intrinsic subtypes: luminal A, luminal B, human epidermal growth factor receptor 2-enriched and basal-like. Epinephrine and norepinephrine, released during stress, bind to adrenoceptors.

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Unlabelled: Treatment of retinoblastoma -a pediatric cancer of the developing retina- might benefit from strategies to inhibit the blood-retinal barrier (BRB). The potent anticancer agent topotecan is a substrate of efflux transporters BCRP and P-gp, which are expressed at the BRB to restrict vitreous and retinal distribution of xenobiotics. In this work we have studied vitreous and retinal distribution, tumor accumulation and antitumor activity of topotecan, using pantoprazole as inhibitor of BCRP and P-gp.

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Background: Breast cancer is the most diagnosed and the major cause of cancer death in women worldwide. Metastasis is the main cause of these deaths. The metastatic cascade involves multiple steps and it has been described that adrenergic receptors can modulate this process at multiple levels.

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Breast cancer is the most frequent malignancy among women worldwide. We have described the expression of α-adrenoceptors in breast cancer cell lines, associated with increased cell proliferation and tumor growth. A mitogenic autocrine/paracrine loop of prolactin (Prl) has been described in breast cancer cells.

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Understanding the mechanisms that govern normal mammary gland development is crucial to the comprehension of breast cancer etiology. β-adrenergic receptors (β-AR) are targets of endogenous catecholamines such as epinephrine that have gained importance in the context of cancer biology. Differences in β-AR expression levels may be responsible for the effects of epinephrine on tumor vs non-tumorigenic breast cell lines, the latter expressing higher levels of β-AR.

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Breast cancer is the most frequent malignancy in women. Several reports demonstrated that adrenergic receptors (ARs) are involved in breast cancer. Here we observed that epinephrine (Epi), an endogenous AR agonist, caused opposite effects in non-tumorigenic (MCF-10A and HBL-100) and tumor cells (MCF-7 and MDA-MB-231).

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The antiestrogenic activity of three natural salpichrolides A, G and B (1, 3 and 4) and of five synthetic analogs containing an aromatic D ring and a simplified side chain (5-9), was evaluated on MCF-7 cells. The 2,3-ene-1-keto steroids 8 and 9 were obtained from 3β-acetoxy-17(13→18)-abeo-5αH-pregna-13,15,17-trien-20-one, the key step for these syntheses being a Wharton carbonyl rearrangement of a 1,2-epoxy-3-keto steroid to the allylic alcohol using hydrazine hydrate. The antiestrogenic activity was evaluated by performing dose-response experiments in ER(+) MCF-7 breast cancer cells.

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