Search

Introduction Triple negative breast cancer (TNBC) is a particularly aggressive subtype of breast cancer (BC) for which very limited therapeutic options are available. Recently, beta-blockers (BB) have been suggested to have favorable effects on the treatment of BC both in preclinical and clinical studies. Objective The aim of this systematic review was to collect evidence from preclinical and clinical studies concerning the scientific evidence for the repurposing of BBs in TNBC treatment. Methods PubMed database was searched for retrieving studies of interest published up to 30/01/2018. All preclinical studies using BC in vitro and in vivo models and assessing the effect of any molecule with sympatholytic or sympathomimetic activity on adrenoceptors were included. Clinical studies concerning BB were considered eligible. Two authors independently reviewed and screened title and abstract of retrieved references. Potentially relevant studies were further assessed through full-texts examination. One author extracted information from preclinical and clinical studies respectively. A second author subsequently reviewed the extracted data. The Newcastle-Ottawa scale was used for the quality assessment of clinical studies. Results A total of 616 study references were initially retrieved. Six additional records were retrieved through snowball search. A total of 62 preclinical studieswere included, of which 46 concerned in vitro and in vivo models of TNBC, i.e. cell cultures and/or animal studies (20 in vitro, 9 in vivo, and 17 in vivo/vitro). In vitro studies showed a high expression of β2 adrenoreceptors in TNBC cell lines. Propranolol, a non-selective β1/β2 antagonist, was reported to significantly decrease proliferation, migration and invasion of TNBC cells. Similar effects were also reported for carvedilol, a selective β2 antagonist and α1 antagonist. In vivo studies reported a reduction of metastasis, angiogenesis and tumor growth in animals exposed to propranolol..Clinical studies, reporting evidence from a total of four distinct retrospective observational cohort studies, showed a beneficial effect of BB in TNBC treatment: e.g. study#1: Overall Survival Hazard Ratio (HR)=0.35 (95%CI 0.12-1.00); study#2: metastasis HR=0.32 (95%CI 0.12–0.90); study3# Progression Free Survival: HR=0.52 (95%CI 0.34–0.79); study #4 Relapse Free Survival: HR=0.69 (95%CI 0.35–1.34). The overall quality of the clinical evidence collected was low. Conclusion: Preclinical evidence collected in this systematic review are in line with the results reported in the four clinical studies retrieved, pointing towards a beneficial effect of BB in the treatment of TNBC. However, given the overall low quality of available evidence, no definite conclusion may be drawn. The execution of large scale interventional clinical studies are warranted to shed light on the efficacy/effectiveness of BB in TNBC treatment. Aknowledgment: This study was supported by Fondazione decima regio “Olga e Raimondo Curri” Citation Format: Spini A, Roberto G, Gini R, Bartolini C, Bazzani L, Donnini S, Crispino S, Ziche M. Preclinical and clinical evidence about the use of betablockers for the treatment of triple negative breast cancer: A systematic review [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P3-14-08.

Aminoflavone (AF), the active component of a novel anticancer agent (AFP464) in phase I clinical trials, is a ligand of the aryl hydrocarbon receptor (AhR). AhR dimerizes with HIF-1β/AhR, which is shared with HIF-1α, a transcription factor critical for the response of cells to oxygen deprivation. To address whether pharmacologic activation of the AhR pathway might be a potential mechanism for inhibition of HIF-1, we tested the effects of AF on HIF-1 expression. AF inhibited HIF-1α transcriptional activity and protein accumulation in MCF-7 cells. However, inhibition of HIF-1α by AF was independent from a functional AhR pathway. Indeed, AF inhibited HIF-1α expression in AhR100 cells, in which the AhR pathway is functionally impaired, yet did not induce cytotoxicity, providing evidence that these effects are mediated by distinct signaling pathways. Moreover, AF was inactive in MDA-MB-231 cells, yet inhibited HIF-1α in MDA-MB-231 cells transfected with the SULT1A1 gene. AF inhibited HIF-1α mRNA expression by ∼50%. Notably, actinomycin-D completely abrogated the ability of AF to downregulate HIF-1α mRNA, indicating that active transcription was required for the inhibition of HIF-1α expression. Finally, AF inhibited HIF-1α protein accumulation and the expression of HIF-1 target genes in MCF-7 xenografts. These results show that AF inhibits HIF-1α in an AhR-independent fashion, and they unveil additional activities of AF that may be relevant for its further clinical development. Cancer Res; 70(17); 6837–48. ©2010 AACR.

In an attempt to identify phytochemicals contributing to the well-documented preventive effect of plant-based diets on cancer incidence and mortality, we have previously shown that certain flavonoids inhibit in vitro angiogenesis. Here, we show that the flavonoid luteolin inhibited tumor growth and angiogenesis in a murine xenograft model. Furthermore, luteolin inhibited vascular endothelial growth factor (VEGF)-induced in vivo angiogenesis in the rabbit corneal assay. In agreement, luteolin inhibited both VEGF-induced survival and proliferation of human umbilical vein endothelial cells (HUVECs) with an IC50 of about 5 μmol/L. Luteolin inhibited VEGF-induced phosphatidylinositol 3′-kinase (PI3K) activity in HUVECs, and this inhibition was critical for both the antisurvival and antimitotic affects of the compound. Indeed, luteolin abolished VEGF-induced activation of Akt, a downstream target of PI3K conveying both survival and mitotic downstream signals. Because overexpression of a constitutively active form of Akt rescued HUVECs only from the antisurvival effects of luteolin, the result indicated that luteolin targeted mainly the survival signals of the PI3K/Akt pathway. With regard to its antimitotic activity, luteolin inhibited VEGF-induced phosphorylation of p70 S6 kinase (S6K), a downstream effector of PI3K responsible for G1 progression. Indeed, VEGF-induced proliferation of HUVECs was sensitive to rapamycin, an inhibitor of p70 S6K activation. Surprisingly, luteolin did not affect VEGF-induced phosphorylation of extracellular signal-regulated kinase 1/2 mitogen-activated protein kinases, a pathway that is considered important for the mitotic effects of VEGF. Thus, blockade of PI3K by luteolin was responsible for the inhibitory effects of the compound on VEGF-induced survival and proliferation of HUVECs. The antisurvival effects of luteolin were mediated via blockage of PI3K/Akt-dependent pathways, whereas inhibition of the PI3K/p70 S6K pathway mediated the antimitotic effects of the compound.

Growth of new blood vessels (angiogenesis), required for all tumor growth, is stimulated by the expression of vascular endothelial growth factor (VEGF). VEGF is up-regulated in all known solid tumors but also in atherosclerosis, diabetic retinopathy, arthritis, and many other conditions. Conventional VEGF isoforms have been universally described as proangiogenic cytokines. Here, we show that an endogenous splice variant, VEGF165b, is expressed as protein in normal cells and tissues and is circulating in human plasma. We also present evidence for a sister family of presumably inhibitory splice variants. Moreover, these isoforms are down-regulated in prostate cancer. We also show that VEGF165b binds VEGF receptor 2 with the same affinity as VEGF165 but does not activate it or stimulate downstream signaling pathways. Moreover, it prevents VEGF165-mediated VEGF receptor 2 phosphorylation and signaling in cultured cells. Furthermore, we show, with two different in vivo angiogenesis models, that VEGF165b is not angiogenic and that it inhibits VEGF165-mediated angiogenesis in rabbit cornea and rat mesentery. Finally, we show that VEGF165b expressing tumors grow significantly more slowly than VEGF165-expressing tumors, indicating that a switch in splicing from VEGF165 to VEGF165b can inhibit tumor growth. These results suggest that regulation of VEGF splicing may be a critical switch from an antiangiogenic to a proangiogenic phenotype.

Based on literature, it is possible to hypothesize that multidrug resistance (MDR) and angiogenic phenotypes are linked to each other in human liver cancer cells. Our goal is to assess whether MDR cells trigger angiogenesis and to study the possible molecular mechanisms involved. Conditioned medium from parental drug-sensitive P5 cells (P5-CM) and MDR-positive P1(0.5) cells [P1(0.5)-CM] stimulated human umbilical vein endothelial cells (HUVEC) survival, proliferation, migration, and microtubular structure formation, but P1(0.5)-CM had a significantly greater effect than P5-CM. Cell implants were done in the rabbit avascular cornea to measure angiogenesis in vivo: P1(0.5) cells induced an important neovascular response in rabbit cornea after 1 week, whereas P5 cells had no effect. P1(0.5) and P5 cells produced vascular endothelial growth factor, but only P1(0.5) secreted hepatocyte growth factor (HGF) into the medium, and small interfering RNA specific for MDR1 clearly reduced HGF production in P1(0.5) cells. The transcription factor Ets-1 and the HGF receptor c-Met were up-regulated in P1(0.5) cells and in HUVEC cultured in P1(0.5)-CM. Inducible nitric oxide synthase (iNOS) seemed to play a major role in the proangiogenic effect of P1(0.5), and its inhibition by 1400W blunted the capacity of P1(0.5) cells to stimulate HUVEC proliferation, migration, and Ets-1 expression. In conclusion, these data show that development of MDR and angiogenic phenotypes are linked to each other in MDR cells. HGF production, Ets-1 and c-Met up-regulation, and iNOS expression can be part of the molecular mechanisms that enhance the angiogenic activity of the MDR-positive hepatocellular carcinoma cell line. (Cancer Res 2006; 66(5): 2673-82)

Prostaglandins, mostly PGE-2, have assumed an important role in cancer biology. Regarding of PGE-2 production, recent investigations have focused on PGE-2 synthases (mPGEs-1, mPGEs-2 and cPGEs), specifically on mPGEs-1, the only inducible enzyme among those so far identified in cells. Whereas cPGEs and mPGEs-2 are constitutively expressed at relatively low levels, mPGEs-1 is highly inducible by pro-inflammatory stimuli. mPGEs-1 upregulation has been detected in many epithelial tumors, and its silencing has been reported to reduce preneoplastic lesions. Despite the evidence linking mPGEs-1 and tumorigenesis, most studies investigating the inducible nature of the enzyme in cultured cells have been performed using a variety of inflammatory stimuli, while little is known about the behavior of the enzyme in tumor cells challenged with oncogenic stimuli. In this work we investigated mPGES-1 regulation in cultured epithelial tumor cells exposed to epidermal growth factor (EGF), an oncogene product which, through its receptor, EGF-receptor, is responsible for tumorigenisis in a wide array of solid tumors. We used three cell lines, representative of colon (HT-29), epidermoid (A431) and lung (A549) tumors, examining the expression of mPGEs-1 protein following EGF-receptor activation by EGF. We found that cells responded to EGF-receptor stimulation with a transient surge of the transcription factor Egr-1, its translocation from cytosol to necleus, an increase of mPGEs-1 mRNA and protein, as well as, an enhanced PGE-2 formation. These changes were suppressed by silencing Egr-1 and by EGF-receptor blockade or by inhibitors of the EGF-receptor-dependent mediators, such as MAP-kinase, ERK1/2. Moreover, cell activation through EGF-receptor induced a tumorigenic phenotype, detectable by clonogenic assay, which regressed when mPGEs-1 was silenced. We also explored the effect of inhibiting the EGF-receptor in A431 xenografts on mPGEs-1 expression and tumor growth, finding a parallel decline of both. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1130. doi:10.1158/1538-7445.AM2011-1130