Applications of engineered exosomes in drugging noncoding RNAs for cancer therapy

Noncoding RNAs (ncRNAs) are engaged in key cell biological and pathological events, and their expression alteration is connected to cancer progression both directly and indirectly. A huge number of studies have mentioned the significant role of ncRNAs in cancer prevention and therapy that make them an interesting subject for cancer therapy. However, there are several limitations, including delivery, uptake, and short half-life, in the application of ncRNAs in cancer treatment. Exosomes are introduced as promising options for the delivery of ncRNAs to the target cells. In this review, we will briefly discuss the application and barriers of ncRNAs. After that we will focus on exosome-based ncRNAs delivery and their advantages as well as the latest achievements in drugging ncRNAs with exosomes.

Potential Protective Role of Melatonin in Benign Mammary Cells Reprogrammed by Extracellular Vesicles from Malignant Cells

(1) Background: Mammary neoplasms in female dogs share many similarities with the same tumor class in humans, rendering these animals a valuable preclinical model for studying novel therapies against breast cancer. The intricate role of extracellular vesicles (EVs), particularly exosomes, in breast carcinogenesis, by transferring specific proteins to recipient cells within the tumor microenvironment, underscores their significance. Melatonin, a hormone recognized for its antitumor effects, adds another layer of intrigue. (2) Methods: EVs obtained from the plasma of dogs diagnosed with mammary tumors were co cultivated with the benign epithelial lineage E-20 using DMEM. The experiment comprised four 24 h treatment groups: control, EVs, melatonin, and EVs + melatonin. A series of assays were conducted, including colony formation, proliferation, and cellular migration assessments. Furthermore, we conducted colony formation, proliferation, and cellular migration assays. We performed immunohistochemistry for proteins of the mTOR pathway, including mTOR and AKT. (3) Results: Exosomes alone significantly increased proliferation, migration, and colony formation rates and, upregulated the expression of mTOR and AKT proteins. However, when melatonin was added, a protective effect was observed. (4) Conclusions: These findings contributed to the use of melatonin to modulate EV-mediated signaling in the clinical veterinary oncology of mammary tumors.

Decoding Hidden Messengers: Proteomic Profiling of Exosomes in Mammary Cancer Research

Cancer is a complex and heterogeneous disease, influenced by various factors that affect its progression and response to treatment. Although a histopathological diagnosis is crucial for identifying and classifying cancer, it may not accurately predict the disease's development and evolution in all cases. To address this limitation, liquid biopsy has emerged as a valuable tool, enabling a more precise and non-invasive analysis of cancer. Liquid biopsy can detect tumor DNA fragments, circulating tumor cells, and exosomes released by cancer cells into the bloodstream. Exosomes attracted significant attention in cancer research because of their specific protein composition, which can provide valuable insights into the disease. The protein profile of exosomes often differs from that of normal cells, reflecting the unique molecular characteristics of cancer. Analyzing these proteins can help identify cancer-associated markers that play important roles in tumor progression, invasion, and metastasis. Ongoing research and clinical validation are essential to advance and effectively utilize protein biomarkers in cancer. Nevertheless, their potential to improve diagnosis and treatment is highly promising. This review discusses several exosome proteins of interest in breast cancer, particularly focusing on studies conducted in mammary tissue and cell lines in humans and experimental animals. Unfortunately, studies conducted in canine species are scarce. This emphasis sheds light on the limited research available in this field. In addition, we present a curated selection of studies that explored exosomal proteins as potential biomarkers, aiming to achieve benefits in breast cancer diagnosis, prognosis, monitoring, and treatment.

Synergistic actions of Alpelisib and Melatonin in breast cancer cell lines with PIK3CA gene mutation

AIMS

Breast cancer (BC) presents high mortality rate and about 25-46 % have mutation in the PIK3CA gene. Alpelisib is a PI3K inhibitor that acts on p110α, which is a subunit of the PI3K protein. The melatonin shown important anti-neoplastic effects and may increase the effectiveness of chemotherapy. This study evaluated the synergistic action of Alpelisib and Melatonin in BC lines carrying the H1047R mutation in PIK3CA, relative to the cellular dynamics and the PI3K/AKT/mTOR pathway.

MAIN METHODS

MDA-MB-468 (triple-ernegative), MDA-MB-453 (H1047R PIK3CA, HER2+) and T-47D cells (H1047R PIK3CA, ER+/PR+) were divided into four treatment groups: control; Melatonin (1 mM); Alpelisib (1 μM); and Alpelisib (1 μM) + Melatonin (1 mM). Cell viability and migration were investigated using the MTT assay and Transwell assay, respectively. Protein expression of PI3K, p-AKT, mTOR, HIF-1α, and caspase-3, was verified using immunocytochemistry.

KEY FINDINGS

MTT assay revealed that MDA-MB-453 and T-47D showed reduction in cell viability in all groups, especially in the MDA-MB-453 treated with Melatonin + Alpelisib. MDA-MB-468 presents reduction in cell migration only with Melatonin, while in the lines with mutation, the treatment of Melatonin + Alpelisib caused inhibition of cell migration. PI3K, p-AKT, mTOR and HIF-1α were inhibited after treatment with Melatonin + Alpelisib in MDA-MB-453 and T-47D lines. The expression of caspase-3 increased in all groups in MDA-MB-453 and T-47D cells, being the increase more pronounced in the Melatonin + Alpelisib group.

SIGNIFICANCE

These results indicate that the combined use of Melatonin and Alpelisib may be more effective in inhibiting BC in women carrying the PIK3CA gene mutation than either treatment alone.

Aging-Related Ovarian Failure and Infertility: Melatonin to the Rescue

Aging has a major detrimental effect on the optimal function of the ovary with changes in this organ preceding the age-related deterioration in other tissues, with the middle-aged shutdown leading to infertility. Reduced fertility and consequent inability to conceive by women in present-day societies who choose to have children later in life leads to increased frustration. Melatonin is known to have anti-aging properties related to its antioxidant and anti-inflammatory actions. Its higher follicular fluid levels relative to blood concentrations and its likely synthesis in the oocyte, granulosa, and luteal cells suggest that it is optimally positioned to interfere with age-associated deterioration of the ovary. Additionally, the end of the female reproductive span coincides with a significant reduction in endogenous melatonin levels. Thus, the aims are to review the literature indicating melatonin production in mitochondria of oocytes, granulosa cells, and luteal cells, identify the multiple processes underlying changes in the ovary, especially late in the cessation of the reproductive life span, summarize the physiological and molecular actions of melatonin in the maintenance of normal ovaries and in the aging ovaries, and integrate the acquired information into an explanation for considering melatonin in the treatment of age-related infertility. Use of supplemental melatonin may help preserve fertility later in life and alleviate frustration in women delaying childbearing age, reduce the necessity of in vitro fertilization–embryo transfer (IVF-ET) procedures, and help solve the progressively increasing problem of non-aging-related infertility in women throughout their reproductive life span. While additional research is needed to fully understand the effects of melatonin supplementation on potentially enhancing fertility, studies published to date suggest it may be a promising option for those struggling with infertility.

Melatonin: A mitochondrial resident with a diverse skill set

Melatonin is an ancient molecule that originated in bacteria. When these prokaryotes were phagocytized by early eukaryotes, they eventually developed into mitochondria and chloroplasts. These new organelles retained the melatonin synthetic capacity of their forerunners such that all present-day animal and plant cells may produce melatonin in their mitochondria and chloroplasts. Melatonin concentrations are higher in mitochondria than in other subcellular compartments. Isolated mouse oocyte mitochondria form melatonin when they are incubated with serotonin, a necessary precursor. Oocyte mitochondria subsequently give rise to these organelles in all adult vertebrate cells where they continue to synthesize melatonin. The enzymes that convert serotonin to melatonin, i.e., arylalkylamine-N-acetyltransferase (AANAT) and acetylserotonin-O-methyltransferase, have been identified in brain mitochondria which, when incubated with serotonin, also form melatonin. Melatonin is a potent antioxidant and anti-cancer agent and is optimally positioned in mitochondria to aid in the maintenance of oxidative homeostasis and to reduce cancer cell transformation. Melatonin stimulates the transfer of mitochondria from healthy cells to damaged cells via tunneling nanotubes. Melatonin also regulates the major NAD⁺-dependent deacetylase, sirtuin 3, in the mitochondria. Disruptions of mitochondrial melatonin synthesis may contribute to a number of mitochondria-related diseases, as discussed in this review.

Modulation of Epithelial Mesenchymal Transition after AGTR-1 Gene Edition by Crispr/Cas9 and Losartan Treatment in Mammary Tumor Cell Line: A Comparative Study between Human and Canine Species

Breast cancer is the most prevalent tumor type among women and female dogs. Tumor malignancy is characterized by the epithelial-to-mesenchymal transition (EMT) which leads to the metastasis formation. The inhibition of angiotensin II type I receptor (AGTR1) by an antagonist such as losartan can suppress angiogenesis, consequently contributing to the metastasis control. The aim of this study was to analyze the capacity of losartan and AGTR-1 gene edition to modulate the EMT process in triple negative/metastatic mammary tumor cells, compared to existing treatment protocols such as carboplatin. The cell lines CF41.Mg and MDA-MB-468, were cultured and treated with carboplatin, losartan, or submitted to AGTR-1 gene edition by CRISPR/Cas9. EMT markers and PARP-1 protein and gene expression were evaluated by immunofluorescence or immunocytochemistry and qRT-PCR, respectively. Cell migration capacity was also evaluated. For CF41.Mg and MDA-MB-468 cell lines, there was an increase in E-cadherin and a decrease in N-cadherin and PARP-1 protein and gene expression after treatment with carboplatin, losartan, both in combination and after AGTR-1 gene edition. There was a decrease in VEGF and PARP-1 protein and gene expression after AGTR-1 gene edition. Moreover, in both lines, reduction in invasion rate was observed after all treatments. Our data suggest that losartan and the gene edition of AGTR-1 by CRISPR/Cas9 were able to block the DNA repair and control the EMT process, such as carboplatin. The results in the canine species are unprecedented, as there are no data in the literature that demonstrate the action of losartan in this tumor type.

Immunohistochemical Evaluation of PARP and Caspase-3 as Prognostic Markers in Prostate Carcinomas

Prostate cancer is the second most common neoplasm among men, with a high mortality rate in advanced stages. Poly (ADP-ribose) polymerase (PARP) plays an important role in repair to DNA damage, being associated with resistance to tumor cell death. Conversely, Caspase-3 is a crucial mediator of programmed cell death, being highly expressed in apoptotic cells. The aim of the present study was to characterize the expression of PARP and Caspase-3 by immunohistochemistry in patients with advanced prostate cancer. PARP and Caspase-3 were independently correlated to patients' evolution, in accordance with the classification of prognostic groups. The increase in PARP expression was positively correlated with tumor patients with poor prognosis (P < 0.0001). In contrast, a decrease in Caspase-3 expression was identified in patients with poor prognosis, when compared with prostate cancer patients with good prognosis (P = 0.0007). Numerically, 92.3% of patients previously classified with poor prognosis showed higher PARP expression, while 93.75% of patients previously classified with good prognosis showed higher levels of Caspase-3. We conclude that PARP and Caspase-3 are potential prognostic markers for prostate cancer patients with different prognosis.

Liquid Biopsy as a Diagnostic and Prognostic Tool for Women and Female Dogs with Breast Cancer

INTRODUCTION

Breast cancer (BC) is the malignant neoplasm with the highest mortality rate in women and female dogs are good models to study BC.

OBJECTIVE

We investigated the efficacy of liquid biopsy to detect gene mutations in the diagnosis and follow-up of women and female dogs with BC.

MATERIALS AND METHODS

In this study, 57 and 37 BC samples were collected from women and female dogs, respectively. After core biopsy and plasma samples were collected, the DNA and ctDNA of the tumor fragments and plasma were processed for next generation sequencing (NGS) assay. After preprocessing of the data, they were submitted to the Genome Analysis ToolKit (GATK).

RESULTS

In women, 1788 variants were identified in tumor fragments and 221 variants in plasma; 66 variants were simultaneously detected in tumors and plasma. Conversely, in female dogs, 1430 variants were found in plasma and 695 variants in tumor fragments; 59 variants were simultaneously identified in tumors and plasma. The most frequently mutated genes in the tumor fragments of women were USH2A, ATM, and IGF2R; in female dogs, they were USH2A, BRCA2, and RRM2. Plasma of women showed the most frequent genetic variations in the MAP3K1, BRCA1, and GRB7 genes, whereas plasma from female dogs had variations in the NF1, ERBB2, and KRT17 genes. Mutations in the AKT1, PIK3CA, and BRIP genes were associated with tumor recurrence, with a highly pathogenic variant in PIK3CA being particularly prominent. We also detected a gain-of-function mutation in the GRB7, MAP3K1, and MLH1 genes.

CONCLUSION

Liquid biopsy is useful to identify specific genetic variations at the beginning of BC manifestation and may be accompanied over the entire follow-up period, thereby supporting the clinicians in refining interventions.

Treatment of Triple Negative Cell Lines with Olaparib to Block DNA Repair

BACKGROUND

The most aggressive breast cancer is the triple negative histological type and the gold standard for its treatment is platinum salts, such as carboplatin. Due to high recurrence, there is a need to test new drugs, such as PARP inhibitors (PARPi) that induce lethality in cells with DNA damage. Olaparib is a PARPi, already used in some tumors, but not tested in canine species. Thus, the aim of this study was demonstrating the efficacy of olaparib in inhibiting DNA repair and controlling disease progression by decreasing the migration capacity of mammary tumor cells.

METHODS

The cell lines, CF41.Mg and MDA-MB-468, were cultured and was performed the MTT to define the best dose of carboplatin. Next, the cells were treated with 10 µM carboplatin, olaparib and with combination of both for 24 hours. PARP-1 protein and gene expression was evaluated by immunofluorescence, western blotting and qRT-PCR, respectively. The analysis of cell migration was performed in transwell chambers.

RESULTS

For CF41.Mg and MDA-MB-468 cell lines, there was decrease in PARP-1 protein and gene expression after treatment with carboplatin, olaparib and both in combination compared to the group without treatment (control) (p<0.05). Moreover, in both lines, reduction in invasion rate was observed after treatment with carboplatin, olaparib and when combined, compared to the control group (p<0.05).

CONCLUSION

Our data suggests that carboplatin and olaparib were able to block DNA repair and control the cancer invasion, especially when used in combination. The results with olaparib in the canine line are unpublished. The olaparib should be a possible agent against human breast cancer and canine mammary tumors.

Liquid Biopsy Can Detect Brca2 Gene Variants In Female Dogs With Mammary Neoplasia

Mammary tumors (MT) is one of the most prevalent malignancies in female dogs and women. Currently, molecular analyzes have shown that each tumor type presents its own genetic signature. In this context, liquid biopsy allows a comprehensive genetic characterization of the tumor, enabling early diagnosis and personalized treatment of patients. In women, deleterious mutations inherited in BRCA2 gene are associated with an increased risk of breast cancer, resistance to therapies, and worse prognosis. In female dogs, there are many divergent data on the involvement of BRCA2 gene with mammary carcinogenesis and what its pathogenic potential is. Therefore, the objective was to identify BRCA2 gene variants in 20 plasma DNA samples, from 10 newly diagnosed dogs with mammary cancer (RD), five control (CTR), and five mastectomized (MAST) patients. Eleven single nucleotide polymorphisms (SNPs) were detected, most of them in the exon 11, and two indels (deletion / insertion) in the BRCA2 gene. However, there was no statistically significant difference in the SNPs/indels detected between the groups. In addition, only one SNP (p.T1425P) and one deletion (p.L2307del) were considered deleterious using in silico computational models. Interestingly, most common variants were present in the plasma of all groups, except for the Ile2614Thr, Ile2614Val, Thr1425Pro, and p.L2307del variants. Thus, we observed that SNPs are common in the BRCA2 gene of female dogs with mammary tumors, with a similar condition identified in women with breast cancer. Liquid biopsy approach in dogs with MT is useful for genetic and therapeutic proposals. This article is protected by copyright. All rights reserved.

Melatonin-Loaded Nanocarriers: New Horizons for Therapeutic Applications

The use of nanosized particles has emerged to facilitate selective applications in medicine. Drug-delivery systems represent novel opportunities to provide stricter, focused, and fine-tuned therapy, enhancing the therapeutic efficacy of chemical agents at the molecular level while reducing their toxic effects. Melatonin (N-acetyl-5-methoxytriptamine) is a small indoleamine secreted essentially by the pineal gland during darkness, but also produced by most cells in a non-circadian manner from which it is not released into the blood. Although the therapeutic promise of melatonin is indisputable, aspects regarding optimal dosage, biotransformation and metabolism, route and time of administration, and targeted therapy remain to be examined for proper treatment results. Recently, prolonged release of melatonin has shown greater efficacy and safety when combined with a nanostructured formulation. This review summarizes the role of melatonin incorporated into different nanocarriers (e.g., lipid-based vesicles, polymeric vesicles, non-ionic surfactant-based vesicles, charge carriers in graphene, electro spun nanofibers, silica-based carriers, metallic and non-metallic nanocomposites) as drug delivery system platforms or multilevel determinations in various in vivo and in vitro experimental conditions. Melatonin incorporated into nanosized materials exhibits superior effectiveness in multiple diseases and pathological processes than does free melatonin; thus, such information has functional significance for clinical intervention.

Part-time cancers and role of melatonin in determining their metabolic phenotype

This brief review describes the association of the endogenous pineal melatonin rhythm with the metabolic flux of solid tumors, particularly breast cancer. It also summarizes new information on the potential mechanisms by which endogenously-produced or exogenously-administered melatonin impacts the metabolic phenotype of cancer cells. The evidence indicates that solid tumors may redirect their metabolic phenotype from the pathological Warburg-type metabolism during the day to the healthier mitochondrial oxidative phosphorylation on a nightly basis. Thus, they function as cancer cells only during the day and as healthier cells at night, that is, they are only part-time cancerous. This switch to oxidative phosphorylation at night causes cancer cells to exhibit a reduced tumor phenotype and less likely to rapidly proliferate or to become invasive or metastatic. Also discussed is the likelihood that some solid tumors are especially aggressive during the day and much less so at night due to the nocturnal rise in melatonin which determines their metabolic state. We further propose that when melatonin is used/tested in clinical trials, a specific treatment paradigm be used that is consistent with the temporal metabolic changes in tumor metabolism. Finally, it seems likely that the concurrent use of melatonin in combination with conventional chemotherapies also would improve cancer treatment outcomes.

Oncolytic effect of Newcastle disease virus is attributed to interferon regulation in canine mammary cancer cell lines

Canine mammary carcinoma (CMC) is one of the major health threats in dogs. The oncolytic virotherapy is a promising strategy to treat canine as well as human cancer patients with non-pathogenic replicating viruses. Here, we evaluated the antitumor activity of one lentogenic, non-lytic Newcastle disease virus (NDV) LaSota strain expressing GFP (NDV-GFP) on five different CMCs and one non-tumorigenic cell line, regarding cell viability, cell death, selectivity index, morphology, global and target gene expression analysis. As evidenced by the selectivity index, all CMC cell lines were more susceptible to NDV-GFP in comparison with the non-tumorigenic cells (~3.1× to ~78.7×). In addition, the oncolytic effect of NDV-GFP was more evident in more malignant CMC cells. Also, we observed an inverse association of the IFN pathway expression and the susceptibility to NDV. The downregulated genes in NDV-GFP-sensitive cells were functionally enriched for antiviral mechanisms by interferon and immune system pathways, demonstrating that these mechanisms are the most prominent for oncolysis by NDV. To our knowledge, this is the first description of oncolysis by an NDV strain in canine mammary cancer cells. We also demonstrated specific molecular pathways related to NDV susceptibility in these cancer cells, opening the possibility to use NDV as a therapeutic-targeted option for more malignant CMCs. Therefore, these results urge for more studies using oncolytic NDVs, especially considering genetic editing to improve efficacy in dogs.

A meta-analysis of microRNA networks regulated by melatonin in cancer: Portrait of potential candidates for breast cancer treatment

Melatonin is a ubiquitous molecule with a broad spectrum of functions including widespread anti-cancer activities. Identifying how melatonin intervenes in complex molecular signaling at the gene level is essential to guide proper therapies. Using meta-analysis approach, herein we examined the role of melatonin in regulating the expression of 46 microRNAs (miRNAs) and their target genes in breast, oral, gastric, colorectal, and prostate cancers, and glioblastoma. The deregulated miRNA-associated target genes revealed their involvement in the regulation of cellular proliferation, differentiation, apoptosis, senescence, and autophagy. Melatonin changes the expression of miRNA-associated genes in breast, gastric, and oral cancers. These genes are associated with cellular senescence, the hedgehog signaling pathway, cell proliferation, p53 signaling, and the hippo signaling pathway. Conversely, colorectal and prostate cancers as well as glioblastoma and oral carcinoma present a clear pattern of less pronounced changes in the expression of miRNA-associated genes. Most notably, colorectal cancer displayed a unique molecular change in response to melatonin. Considering breast cancer network complexity, we compared the genes found during the meta-analysis with RNA-Seq data from breast cancer-bearing mice treated with melatonin. Mechanistically, melatonin upregulated genes associated with immune responses and apoptotic processes, whereas it downregulated genes involved in cellular aggressiveness/metastasis (eg, mitosis, telomerase activity, and angiogenesis). We further characterized the expression profile of our gene subsets with human breast cancer and found eight upregulated genes and 16 downregulated genes that were appositively correlated with melatonin. Our results pose a multi-dimension network of tumor-associated genes regulated by miRNAs potentially targeted by melatonin.

Therapeutic Potential of Melatonin in the Regulation of MiR-148a-3p and Angiogenic Factors in Breast Cancer

BACKGROUND

The high mortality rate of breast cancer is related to the occurrence of metastasis, a process that is promoted by tumor angiogenesis. MicroRNAs are small molecules of noncoding mRNA that play a key role in gene regulation and are directly involved in the progression and angiogenesis of various tumor types, including breast cancer. Several miRNAs have been described as promoters or suppressors angiogenesis and may be associated with tumor growth and metastasis. Melatonin is an oncostatic agent with a capacity of modifying the expression of innumerable genes and miRNAs related to cancer.

OBJECTIVE

The aim of this study was to evaluate the role of melatonin and the tumor suppressor miR- 148a-3p on angiogenesis of breast cancer.

METHOD

MDA-MB-231 cells were treated with melatonin and modified with the overexpression of miR-148a-3p. The relative quantification in real-time of miR-148a-3p, IGF-IR and VEGF was performed by real-time PCR. The protein expression of these targets was performed by immunocytochemistry and immunohistochemistry. Survival, migration and invasion rates of tumor cells were evaluated. Finally, the xenograft model of breast cancer was performed to confirm the role of melatonin in the tumor.

RESULTS

The melatonin was able to increase the gene level of miR-148a-3p and decreased the gene and protein expression of IGF-1R and VEGF, both in vitro and in vivo. In addition, it also had an inhibitory effect on the survival, migration and invasion of breast tumor cells.

CONCLUSION

Our results confirm the role of melatonin in the regulation of miR-148a-3p and decrease of angiogenic factors.

Evaluation of melatonin and AFMK levels in women with breast cancer

PURPOSE

Changes in the circadian rhythm may contribute to the development of cancer and are correlated with the high risk of breast cancer (BC) in night workers. Melatonin is a hormone synthesized by the pineal gland at night in the absence of light. Levels of melatonin and the metabolite of oxidative metabolism AFMK (acetyl-N-formyl-5-methoxykynurenamine), are suggested as potential biomarkers of BC risk. The aims of this study were to evaluate levels of melatonin and AFMK in women recently diagnosed with BC, women under adjuvant chemotherapy, and night-shift nurses, and compare them with healthy women to evaluate the relation of these compounds with BC risk.

METHODS

Blood samples were collected from 47 women with BC, 9 healthy women, 10 healthy night shift nurses, and 6 patients under adjuvant chemotherapy. Compound levels were measured by mass spectrometry.

RESULTS AND CONCLUSIONS

Our results showed that women with BC had lower levels of melatonin compared to control group women, and even lower in night-shift nurses and in patients under adjuvant chemotherapy. There was no significant difference of AFMK levels between the groups. In addition to this, high levels of melatonin and AFMK were related to patients with metastasis, and high levels of AFMK were related to the presence of lymph node-positive, tumor > 20 mm and patients who sleep with light at night. Our results showed a reduction of melatonin levels in BC patients, suggesting a relation with the disease, and in addition, point to the importance of melatonin supplementation in women that work at night to reduce the BC risk.

Abstract B25: Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors

Introduction: The angiogenesis process is regulated by numerous factors, especially the hypoxia-inducible factor 1alpha (HIF-1 alpha) and vascular endothelial growth factor (VEGF). The HIF-1 is a central regulator of pathophysiologic response of cells to hypoxia conditions, able to activate transcription of the gene that promotes the induction of VEGF, which in turn promotes angiogenesis through its ability to stimulate growth, migration, and invasion of endothelial cells, leading to the formation of new blood vessels and subsequent tumor growth. Metformin has demonstrated its ability to reduce the incidence of cancer in diabetic patients with positive results, especially in breast cancer, inhibiting cell growth by AMPK/Akt/mTOR signaling pathway. Likewise, LY294002, a PI3K signaling pathway inhibitor, has antiangiogenic features. In this context, the aim of this study was to evaluate the effectiveness of metformin and LY294002 inhibitor treatment in angiogenesis as a therapeutic strategy in mammary tumors in an in vitro and in vivo study.

Materials and Methods: In the in vitro study, canine mammary tumor cell line (CF41) was cultured in DMEM high-glucose culture medium, at 37°C in 5% CO2. Cell viability was measured by MTT assay after treatment with different concentrations of metformin and LY294002 inhibitor. Once established the concentration of 5 mM for metformin and 5 µM of LY294002, the protein and gene expression of HIF-1alpha and VEGF were detected by immunocytochemistry and real-time PCR, respectively. For an in vivo study, CF41 were injected in nude athymic female mice and treated with metformin (200 mg/kg i.p.) for 4 weeks and LY294002 (7.5 mg/kg intratumorally) every 3 days for three times. At the end, mice were euthanized and the tumors were collected to determine the protein and gene expression of HIF-1alpha and VEGF and microvessel density by immunohistochemistry for CD31. The immunostaining was quantified by optical densitometry technique, slides were analyzed and photographed in Nikon Eclipse E200 microscope at 40X objective, and proteins were quantified by the ImageJ software analysis. For real-time PCR, the relative expression of the genes of interest was determined by DataAssist v3.0 software, using Ct method.

Results: There was a significant decrease of cell viability after treatment with different concentrations of metformin and LY294002 in 24 hours. Both HIF-1alpha and VEGFA protein and gene expression significantly decreased after treatment with metformin and LY294002 or in combination. Furthermore, in animals, there was a decrease in tumor size, protein and gene expression of HIF-1alpha and VEGFA, in addition to a decrease of CD31 expression after all treatments.

Conclusion: Our results suggest the potential effectiveness of metformin and LY294002 acting in angiogenesis process of mammary tumors.

Financial support: FAPESP.

Citation Format: Marina Gobbe Moschetta, Camila Leonel, Larissa Bazela Maschio-Signorini, Thaiz Ferraz Borin, Gabriela Bottaro Gelaleti, Lívia Carvalho Ferreira, Bruna Victorasso Jardim-Perassi, Nathália Martins Sonehara, Debora Aparecida Pires de Campos Zuccari. Meformin and LY294002 treatment regulate angiogenesis process through PI3K-MAPK/AKT/mTOR signaling pathways in mammary tumors [abstract]. In: Proceedings of the AACR International Conference held in cooperation with the Latin American Cooperative Oncology Group (LACOG) on Translational Cancer Medicine; May 4-6, 2017; São Paulo, Brazil. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(1_Suppl):Abstract nr B25.

Inhibition of Epithelial-mesenchymal Transition in Response to Treatment with Metformin and Y27632 in Breast Cancer Cell Lines

BACKGROUND

ROCK-1 expression is associated with the malignant character of tumors, while inhibiting this molecule results in a significant suppression of tumor metastasis. Likewise, transforming growth factor beta (TGF-β) is associated with this malignancy by having the ability to induce epithelial-mesenchymal transition (EMT). Metformin, a drug used in the treatment of diabetes, has previously been shown to inhibit EMT in breast cancer cells.

OBJECTIVE

The aim of this study is to evaluate the TGF-β1 action model for induction of EMT and the action of metformin and ROCK-1 inhibitor (Y27632) in EMT process in breast cancer cell lines.

METHOD

MCF-7 and MDA-MB-231 cell lines were treated with metformin and Y27632, after induction of EMT by TGF-β1, to examine the effects on cell migration as well as the protein expression of the ROCK-1 markers, vimentin, E-cadherin, CD44 and CD24 by immunocitochemistry.

RESULTS

There was a lower protein expression of ROCK-1, vimentin, CD44 and CD24 in both cell lines after treatment with metformin and Y27632. In MDA-MB-231 cells, E-cadherin expression was increased in all treatment groups. Treatment of MDA-MB-231 cell line with metformin and Y27632 significantly reduced the invasion of these cells.

CONCLUSION

This study confirms the benefits of metformin and Y27632 as potential therapeutic agents in mammary tumors, by blocking EMT process and metastatic potential.

Evaluation of Melatonin Effect on Human Breast Cancer Stem Cells Using a Threedimensional Growth Method of Mammospheres

BACKGROUND

The high rates of women&amp;#039;s death from breast cancer occur due to acquired resistance by patients to certain treatments, enabling the recurrence and/or tumor growth, invasion and metastasis. It has been demonstrated that the presence of cancer stem cells in human tumors, as responsible for recurrence and resistance to therapy. Studies have identified OCT4 as responsible for self-renewal and maintenance of pluripotency of stem cells. Thus, it is interesting to study potential drugs that target this specific population in breast cancer. Melatonin, appears to have oncostatic effects on cancer cells, however, little is known about its therapeutic effect on cancer stem cells.

OBJECTIVE

Evaluate the viability and the expression of OCT4 in breast cancer stem cells, MCF-7 and MDA-MB- 231, after melatonin treatment.

METHOD

The cells were grown in a 3-dimensional model of mammospheres, representing the breast cancer stem cell population and treated or not with melatonin. The cell viability of mammospheres were evaluated by MTT assay and the OCT4 expression, a cancer stem cells marker, was verified by immunocitochemistry.

RESULTS

Our results demonstrated that the melatonin treatment decreased the cell viability of MCF-7 and MDAMB- 231 mammospheres. Furthermore, it was observed that in both cell lines, the expression of OCT4 was decreased in melatonin-treated cells compared to the control group.

CONCLUSIONS

This fact suggests that melatonin is effective against breast cancer stem cells inhibiting the cell viability via OCT 4. Based on that, we believe that melatonin has a high potential to be used as an alternative treatment for breast cancer.

Abstract 884: Detection of intratumoral heterogeneity using MR-defined tumor habitats in breast cancer model under melatonin treatment

Breast cancer shows high intratumoral heterogeneity, which can be visualized as localized sub-populations of tumor cells with different malignancy potential and treatment responsiveness. These regions are like “habitats” that contain different combinations of environmental selection forces, such as hypoxia, acidosis, or nutrient availability. Thus, agents that can perturb these forces may be useful in limiting cancer progression. Studies have shown that melatonin can affect tumor metabolism and we hypothesize that this may be a mechanism by which the disruption of circadian melatonin production by light exposure at night (LAN) promotes breast cancer initiation and progression. The aim of this study was to evaluate the effect of melatonin on intratumoral heterogeneity measured by non-invasive MR imaging in a syngeneic mouse model of breast cancer (4T1). To visualize habitats, clusters were generated from combined MR images generated by different pulse sequences. These were co-registered with histology using tumor specific 3-D printed cradles to classify these tumor habitats. Methods: Mice were exposed to LAN (Control) or LAN plus melatonin. The melatonin metabolite 6-sulfatoxymelatonin (6-SMT) was assessed in urine as a measure of melatonin production. Mice were imaged in a 7T MRI system with: 1) anatomical T2 images, 2) T2*, 3) diffusion-weighted MRI (DWI); and 4) T1 weighted dynamic contrast enhanced (DCE). DCE maps were obtained through semi-quantitative analysis of the pre- and post-contrast agent bolus time-series on a pixel-by-pixel basis. These were combined to the corresponding T2, T2* and Apparent Diffusion Coefficient (ADC) values to generate parameter maps. Parameter maps were used to classify multiple clusters, based on a Gaussian mixture model. Following euthanasia, a 3D printed mold based on the T2 tumor isosurface was created in order to co-register the MRI and histology. Tumors were stained with H&E and for pimonidazole (hypoxia) by immunohistochemistry. Results: Melatonin treatment increased the 6-SMT in urine of mice exposed to LAN and statistically reduced tumor growth by day 15 (p&lt;0.05). Distinct hypoxic habitats have been observed by MRI. Habitat clusters with low values in ADC (high cellularity) and low contrast enhancement were associated with positive staining of pimonidazole. Initial results suggest that the melatonin-treated mice had more homogeneous tumors, although additional numbers will be needed to reach statistical significance. Conclusion: These data indicate that the spatial heterogeneity of breast tumors, corroborated by histological features, may be used as a non-invasive imaging method for monitoring the changes in intratumoral heterogeneity following cancer therapy.

Citation Format: Bruna V. Jardim-Perassi, William Dominguez-Viqueira, Asmaa El-Kenawi, Dominique F. Abrahams, Mikalai Budzevich, Epifanio Ruiz, Suning Huang, Pedro M. Enriquez-Navas, Gary Martinez, Debora Aparecida Pires de Campos Zuccari, Robert J. Gillies. Detection of intratumoral heterogeneity using MR-defined tumor habitats in breast cancer model under melatonin treatment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 884. doi:10.1158/1538-7445.AM2017-884

Efficacy of melatonin, IL-25 and siIL-17B in tumorigenesis-associated properties of breast cancer cell lines

Mammary tumorigenesis can be modulated by melatonin, which has oncostatic action mediated by multiple mechanisms, including the inhibition of the activity of transcription factors such as NF-κB and modulation of interleukins (ILs) expression. IL-25 is an active cytokine that induces apoptosis in tumor cells due to differential expression of its receptor (IL-17RB). IL-17B competes with IL-25 for binding to IL-17RB in tumor cells, promoting tumorigenesis. This study purpose is to address the possibility of engaging IL-25/IL-17RB signaling to enhance the effect of melatonin on breast cancer cells. Breast cancer cell lines were cultured monolayers and 3D structures and treated with melatonin, IL-25, siIL-17B, each alone or in combination. Cell viability, gene and protein expression of caspase-3, cleaved caspase-3 and VEGF-A were performed by qPCR and immunofluorescence. In addition, an apoptosis membrane array was performed in metastatic cells. Treatments with melatonin and IL-25 significantly reduced tumor cells viability at 1mM and 1ng/mL, respectively, but did not alter cell viability of a non-tumorigenic epithelial cell line (MCF-10A). All treatments, alone and combined, significantly increased cleaved caspase-3 in tumor cells grown as monolayers and 3D structures (p<0.05). Semi-quantitative analysis of apoptosis pathway proteins showed an increase of CYTO-C, DR6, IGFBP-3, IGFBP-5, IGFPB-6, IGF-1, IGF-1R, Livin, P21, P53, TNFRII, XIAP and hTRA proteins and reduction of caspase-3 (p<0.05) after melatonin treatment. All treatments reduced VEGF-A protein expression in tumor cells (p<0.05). Our results suggest therapeutic potential, with oncostatic effectiveness, pro-apoptotic and anti-angiogenic properties for melatonin and IL-25-driven signaling in breast cancer cells.

Melatonin Regulates Angiogenic and Inflammatory Proteins in MDA-MB-231 Cell Line and in Co-culture with Cancer-associated Fibroblasts

BACKGROUND

Cancer-associated fibroblast (CAFs) are the most abundant cells in the tumor microenvironment, able to secrete growth factors and act on tumor progression. Melatonin is associated with several mechanisms of action with oncostatics and oncoprotectors effects, and also participate in the reduction of synthesis of surrounding fibroblasts and endothelial cells in breast cancer.

OBJECTIVE

The objectives of this study were to determine the effectiveness of melatonin in cell viability and expression of proteins involved in angiogenesis and inflammation in triplenegative mammary tumor cell line (MDA-MB-231) and in co-culture with CAFs.

METHOD

Cell viability was measured by MTT assay and the protein expression was evaluated by Membrane Antibody Array after melatonin treatment.

RESULTS

Melatonin treatment (1 mM) for 48 hours reduced the cell viability of MDA-MB-231, CAFs and co-culture (p < 0.05). The semi-quantitative protein analysis showed that when monoculture of tumor cells were compared with co-culture of CAFs, there was a regulation of angiogenic and inflammatory proteins (p < 0.05). Melatonin treatment also leads a differential expression of angiogenic and inflammatory proteins in both monoculture and co-culture of tumor cells and CAFs (p < 0.05).

CONCLUSION

The influence of CAFs under the tumor microenvironment was confirmed, increasing the malignancy of the tumor. In addition, melatonin is effective in both monoculture and co-culture, regulating angiogenic and inflammatory proteins that contribute to tumor progression. This study show an overview of melatonin ability in regulating angiogenic and inflammatory proteins, and opens the way for exploration of each individual protein in further studies.

Inhibition of Epithelial-Mesenchymal Transition and Metastasis by Combined TGFbeta Knockdown and Metformin Treatment in a Canine Mammary Cancer Xenograft Model

Epithelial mesenchymal transition (EMT) is a process by which epithelial cells acquire mesenchymal properties, generating metastases. Transforming growth factor beta (TGF-β) is associated with this malignancy by having the ability to induce EMT. Metformin, has been shown to inhibit EMT in breast cancer cells. Based on this evidence we hypothesize that treatment with metformin and the silencing of TGF-β, inhibits the EMT in cancer cells. Canine metastatic mammary tumor cell line CF41 was stably transduced with a shRNA-lentivirus, reducing expression level of TGF-β1. This was combined with metformin treatment, to look at effects on cell migration and the expression of EMT markers. For in vivo study, unmodified or TGF-β1sh cells were injected in the inguinal region of nude athymic female mice followed by metformin treatment. The mice's lungs were collected and metastatic nodules were subsequently assessed for EMT markers expression. The migration rate was lower in TGF-β1sh cells and when combined with metformin treatment. Metformin treatment reduced N-cadherin and increased E-cadherin expression in both CF41 and TGF-β1sh cells. Was demonstrated that metformin treatment reduced the number of lung metastases in animals bearing TGF-β1sh tumors. This paralleled a decreased N-cadherin and vimentin expression, and increased E-cadherin and claudin-7 expression in lung metastases. This study confirms the benefits of TGF-β1 silencing in addition to metformin as potential therapeutic agents for breast cancer patients, by blocking EMT process. To the best of our knowledge, we are the first to report metformin treatment in cells with TGF-β1 silencing and their effect on EMT.

Melatonin Regulates Angiogenic Factors under Hypoxia in Breast Cancer Cell Lines

Angiogenesis is the process of new blood vessel formation, regulated by a number of pro- and antiangiogenic factors and usually begins in response to hypoxia. Exogenous administration of melatonin has shown numerous anti-tumor effects and appears to inhibit tumor angiogenesis. However, many factors involved in the anti-angiogenic effect of melatonin are still under investigation. Here, we evaluate the effects of melatonin on cell viability and expression of angiogenic factors in MCF-7 and MDA-MB-231 breast cancer cells under hypoxic conditions. Cell viability was investigated by MTT and gene and protein expression of the hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF-A) were verified by qPCR and immunocytochemistry after melatonin treatment (1 mM) under hypoxic conditions. Additionally, a protein array with 20 different cytokines/factors was performed on tumor cell lysates. The results showed that 1 mM of melatonin reduced the viability of MCF-7 and MDA-MB-231 cells (p < .05). This treatment also decreased both gene and protein expression of HIF-1α and VEGF-A under hypoxic conditions (p < .05). Among the proteins evaluated by protein array, melatonin treatment during hypoxia reduced VEGF-C, VEGFR receptors (VEGFR2 and VEGFR3), matrix metalloproteinase 9 (MMP9) and Angiogenin in MCF-7 cells. In MDA-MB-231 cells, a significant decrease was observed in VEGFR2, epidermal growth factor receptor (EGFR) and Angiogenin (p < .05). Taken together, these results showed that melatonin acts in the regulation of angiogenic factors in breast tumor cells and suggests an anti-angiogenic activity, particularly under hypoxic conditions.

Effect of Curcumin on Pro-angiogenic Factors in the Xenograft Model of Breast Cancer

The formation of a new blood vessel is stimulated by angiogenic factors. Curcumin, which is the active ingredient of the spice plant Curcuma longa L and is used as food and traditional medicine, has shown anticancer effects against different types of cancers. We evaluated the effects of curcumin on angiogenesis/pro-angiogenic factors in a mouse model of human breast cancer. Cell viability was measured by the MTT assay after curcumin treatment in triple-negative breast cancer cells (MDA-MB-231). For the in vivo study, human breast cancer was induced in athymic mice and treated with 300 mg/kg/day of curcumin administered intraperitoneally. Tumor size was measured weekly, and the animals underwent single photon emission computed tomography (SPECT) scanning with Tc-99m tagged VEGF-c to detect the in vivo expression of VEGFR2/3. In addition, the expression of proangiogenic/ growth factors in the tumor extracts was evaluated by a membrane antibody array. Histological analysis was performed to confirm the effect of curcumin on neovascularization. The MTT assay showed that curcumin significantly reduced the cell viability of MDA-MB-231 cells. In breast cancer xenografts, curcumin treatment led to a decrease in tumor volume and cell proliferation (Ki-67) compared with the vehicle treated group. Tc-99m-HYNIC-VEGF-c-SPECT imaging showed decreased uptake to the tumor, which may indicate a lower expression of VEGFR2/3 in curcumin treated tumors; however, a statistically significant difference was not achieved (p>0.05). Additionally, curcumin treatment showed a significantly low level of expression of pro-angiogenic factors (p<0.05) and a decrease in micro-vessel density (vWF) in animals compared with that of vehicle treated tumors. In conclusion, curcumin treatment showed effectiveness in reducing tumor growth and cell proliferation, as well as in the inhibition of angiogenesis.

Abstract B38: Melatonin efficacy in breast cancer microenvironment under acidosis

Breast cancer is the most common neoplasia among women and has been frequently associated to high morbidities and mortalities rates. Cancer progression is strongly influenced by conditions of tumor microenvironment. Rapid tumor growth results in decreased of oxygen intake, restricting metabolic demands in specific regions of tumor. This poor perfusion coupled with preferential anaerobic glycolysis leads to acidification of tumor microenvironment. Survival mechanisms of tumor cells under acidic conditions are not well characterized, but has been shown that adverse conditions in tumor microenvironment can select phenotypes that are able to adapted to survival and growth in low pH conditions, hence resulting in tumor progression. Thus, controlling these adverse conditions in tumor microenvironment is a promising tactic in limiting cancer development. Melatonin, a hormone naturally produced and secreted by pineal gland, appears to play multiple roles in cancer and it is proposed as a possible keeper of an extreme environment hindering the survival of these cells. In this study, the benefits of melatonin treatment on cell viability of breast cancer cell lines under acidosis condition were evaluated. Breast cancer cell lines estrogen receptor (ER)-positive (MCF-7) and ER-negative (MDA-MB-231) were cultured in Dulbecco's Modified Eagle's medium (DMEM) at 37°C in 5% CO2. Cell viability was measured using an MTT assay. Individual wells of a 96-well plate were seeded with 100 µL of medium containing 0.05 x 106 cells and cells were separated into the following groups: Group 1) Cells cultured in pH 7.4 with DMEM (control); Group 2) Cells cultured in pH 6.7 with DMEM supplemented with 25 mmol/L buffer 2- (N-Morpholino) ethanesulfonic acid (MES) for 24 hours, to mimic an acute acidosis in tumor microenvironment; Group 3) Cells cultured with DMEM supplemented with 25 mmol/L MES and treated with 1 mM of melatonin for 24 hours; Group 4) Cells cultured with DMEM supplemented with 25 mmol/L MES for 12 hours and treated with 1 mM of melatonin for an addition 12 hours. After treatments, MTT solution were added to each well, and the plates were incubated at 37°C for an additional 4 hour. To solubilize the MTT formazan crystals, the cells were incubated with dimethyl sulfoxide (DMSO) for 10 minutes and absorbance was measured at 540 nm. Cell viability (%) was calculated for all groups compared to control samples. The results were compared by ANOVA, followed by the Bonferroni test. The results showed that there was a decrease of both MCF-7 and MDA-MB-231 cells viability under acute acidosis conditions (Group 1 vs Group 2, p &lt; 0.05). MCF-7 cells showed 65.36 ± 1.16 % of cell viability while MDA-MB-231 cells showed 52.98 ± 0.90 of cell viability under acidosis conditions (Group 2). Melatonin treatment for 24 hours was effective in reducing cell viability in acidosis conditions, leading to a decrease in MCF-7 cells (Group 3: 52.41 ± 1.32 %) and MDA-MB-231 cells (Group 3: 47.83 ± 0.67 %) when compared with cells under acidosis without treatment (Group 2 vs Group 3, p &lt; 0.05). Furthermore, in both cell lines there was a decrease in cell viability in Group 4 (MCF-7 = 54.24 ± 1.22 %; MDA-MB-231 = 45.60 ± 0.45 %) compared to cells under acidosis (Group 2 vs Group 4, p &lt; 0.05), and no difference was observed when compared with cells under acidosis and treated with melatonin for 24 hours (Group 3 vs Group 4, p &gt; 0.05). In conclusion, our results show that acute acidosis reduces the viability of breast cancer cells and melatonin treatment is effective, leading to decrease the cell viability under acute acidosis.In addition, studies are being madeto evaluate the effectiveness of melatonin also in chronic acidosis conditions, and to investigate its signaling pathways in the extreme tumor microenvironment, in order to confirm potential effectiveness of melatonin in breast cancer in these conditions.

Citation Format: Nathália Martins Sonehara, Bruna Victorasso Jardim-Perassi, André de Lima Mota, Marina Gobbe Moschetta, Debora Aparecida Pires de Campos Zuccari, Rubens de Paula, Jr. Melatonin efficacy in breast cancer microenvironment under acidosis. [abstract]. In: Proceedings of the AACR Special Conference: Metabolism and Cancer; Jun 7-10, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(1_Suppl):Abstract nr B38.

Melatonin decreases breast cancer metastasis by modulating Rho-associated kinase protein-1 expression

The occurrence of metastasis, an important breast cancer prognostic factor, depends on cell migration/invasion mechanisms, which can be controlled by regulatory and effector molecules such as Rho-associated kinase protein (ROCK-1). Increased expression of this protein promotes tumor growth and metastasis, which can be restricted by ROCK-1 inhibitors. Melatonin has shown oncostatic, antimetastatic, and anti-angiogenic effects and can modulate ROCK-1 expression. Metastatic and nonmetastatic breast cancer cell lines were treated with melatonin as well as with specific ROCK-1 inhibitor (Y27632). Cell viability, cell migration/invasion, and ROCK-1 gene expression and protein expression were determined in vitro. In vivo lung metastasis study was performed using female athymic nude mice treated with either melatonin or Y27832 for 2 and 5 wk. The metastases were evaluated by X-ray computed tomography and single photon emission computed tomography (SPECT) and by immunohistochemistry for ROCK-1 and cytokeratin proteins. Melatonin and Y27632 treatments reduced cell viability and invasion/migration of both cell lines and decreased ROCK-1 gene expression in metastatic cells and protein expression in nonmetastatic cell line. The numbers of 'hot' spots (lung metastasis) identified by SPECT images were significantly lower in treated groups. ROCK-1 protein expression also was decreased in metastatic foci of treated groups. Melatonin has shown to be effective in controlling metastatic breast cancer in vitro and in vivo, not only via inhibition of the proliferation of tumor cells but also through direct antagonism of metastatic mechanism of cells rendered by ROCK-1 inhibition. When Y27632 was used, the effects were similar to those found with melatonin treatment.

Molecular markers of angiogenesis and metastasis in lines of oral carcinoma after treatment with melatonin

BACKGROUND

Oral cancer is the most common type of head and neck cancer and its high rate of mortality and morbidity is closely related to the processes of angiogenesis and tumor metastasis. The overexpression of the pro-angiogenic genes, HIF-1α and VEGF, and pro-metastatic gene, ROCK-1, are associated with unfavorable prognosis in oral carcinoma. Melatonin has oncostatic, antiangiogenic and antimetastatic properties in several types of neoplasms, although its relationship with oral cancer has been little explored. This study aims to analyze the expression of the genes HIF-1α, VEGF and ROCK-1 in cell lines of squamous cell carcinoma of the tongue, after treatment with melatonin.

METHODS

SCC9 and SCC25 cells were cultured and cell viability was assessed by MTT assay, after treatment with 100 μM of CoCl2 to induce hypoxia and with melatonin at different concentrations. The analysis of quantitative RT-PCR and the immunocytochemical analysis were performed to verify the action of melatonin under conditions of normoxia and hypoxia, on gene and protein expression of HIF-1α, VEGF and ROCK-1.

RESULTS

The MTT assay showed a decrease in cell viability in both cell lines, after the treatment with melatonin. The analysis of quantitative RT-PCR indicated an inhibition of the expression of the pro-angiogenic genes HIF-1α (P < 0.001) and VEGF (P < 0.001) under hypoxic conditions, and of the pro-metastatic gene ROCK-1 (P < 0.0001) in the cell line SCC9, after treatment with 1 mM of melatonin. In the immunocytochemical analysis, there was a positive correlation with gene expression data, validating the quantitative RT-PCR results for cell line SCC9. Treatment with melatonin did not demonstrate inhibition of the expression of genes HIF-1α, VEGF and ROCK-1 in line SCC25, which has different molecular characteristics and greater degree of malignancy when compared to the line SCC9.

CONCLUSION

Melatonin affects cell viability in the SCC9 and SCC25 lines and inhibits the expression of the genes HIF-1α, VEGF and ROCK-1 in SCC9 line. Additional studies may confirm the potential therapeutic effect of melatonin in some subtypes of oral carcinoma.

Abstract A03: Effectiveness of melatonin on the epithelial mesenchymal transition after induction with transforming growth factor beta (TGF-β)

Background: The mammary tumors are the most frequent in women in Brazil and worldwide. The high mortality rate in breast cancer is mainly due to invasiveness and metastatic. The metastatic process involves a mechanism called epithelial-mesenchymal transition (EMT). The EMT mechanism can be induced by growth factors such as transforming growth factor beta (TGF-β), which alters the epithelial phenotype (E-cadherin) to a mesenchymal phenotype (n-caderina/vimentina). Studies have shown significant importance of the epithelial mesenchymal transition in breast cancer, which makes the study of new therapeutic agents that act in the process, very important. Melatonin, a hormone naturally secreted by the pineal gland, has shown oncostatic properties. For these reasons, the aim of this study was to evaluate the anti-metastatic potential of melatonin by the epithelial mesenchymal transition induced by TGF-β in breast cancer cell line. Methods: The breast cancer cell line MCF-7 was cultured at 37 ° C and 5% CO2 in DMEM High Glucose culture medium. Once established, the best concentration of TGF-β (0.5 ng / mL) to induce epithelial mesenchymal transition the cells were divided into four groups (Group I - Control, Group II - TGF-β, Group III - Melatonin and Group IV - TGF- β + Melatonin) to evaluate the protein expression of E-cadherin, N-cadherin and vimentin by immunocytochemistry. Quantitation of immunoreactivity was performed by densitometry (ImageJ software). The results were compared by ANOVA followed by Bonferroni. Results: The results showed that there were statistically significant increased protein e-cadherin in cells treated with melatonin (P &lt; 0.05) when compared to cells treated with TGF-β. Furthermore, immunostaining of proteins N-cadherin and vimentin was lower in cells treated with TGF-B + melatonin (P &lt; 0.05) compared to cells treated only with TGF-β. Conclusion: Melatonin interfered in the expression of proteins related to epithelial mesenchymal transition after induction with TGF-B which may suggested a possible anti-metastatic role of this hormone.

Citation Format: Naiane do Nascimento Gonçalves, Lívia Carvalho Ferreira, Juliana Ramos Lopes, Larissa Bazela Maschio, Marina Gobbe Moschetta, Gabriela Bottaro Gelaleti, Gustavo Rodrigues Martins, Debora Aparecida Pires de Campos Zuccari. Effectiveness of melatonin on the epithelial mesenchymal transition after induction with transforming growth factor beta (TGF-β). [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr A03. doi:10.1158/1538-7445.CHTME14-A03

Immunoexpression of ROCK-1 and MMP-9 as prognostic markers in breast cancer

Breast cancer is the most common tumor in women and it has high mortality mainly due to the occurrence of tumor metastasis. Both the processes of cell migration and anchorage to the substrate are essential for the development of metastasis. These processes occur by rearrangements of the actin cytoskeleton, regulated by Rho-associated protein kinase 1 (ROCK-1). The degradation of the extracellular matrix, influenced by metalloproteinase 9 (MMP-9) also exerts greater cell invasiveness. The present study evaluated the ROCK-1 and MMP-9 proteins using an immunohistochemical method through the selection of invasive ductal breast carcinoma. The protein expression was correlated to clinicopathological parameters and overall survival of the patients. High expression of the ROCK-1 protein was correlated statistically to the status of lymph nodes (p=0.007) and showed variable expression in different clinical stages of the tumor. MMP-9 showed a strong immunostaining in patients with metastasis that had died, whereas there was no marker in normal breast tissues. In addition, 46.6% of patients classified as poor prognosis showed high expression of ROCK-1 and MMP-9 protein and another 40.0% just showed high expression of MMP-9. Thus, the differential expression of ROCK-1 and MMP-9 proteins suggests their potential use as prognostic markers in breast cancer.

Effect of melatonin on tumor growth and angiogenesis in xenograft model of breast cancer

As neovascularization is essential for tumor growth and metastasis, controlling angiogenesis is a promising tactic in limiting cancer progression. Melatonin has been studied for their inhibitory properties on angiogenesis in cancer. We performed an in vivo study to evaluate the effects of melatonin treatment on angiogenesis in breast cancer. Cell viability was measured by MTT assay after melatonin treatment in triple-negative breast cancer cells (MDA-MB-231). After, cells were implanted in athymic nude mice and treated with melatonin or vehicle daily, administered intraperitoneally 1 hour before turning the room light off. Volume of the tumors was measured weekly with a digital caliper and at the end of treatments animals underwent single photon emission computed tomography (SPECT) with Technetium-99m tagged vascular endothelial growth factor (VEGF) C to detect in vivo angiogenesis. In addition, expression of pro-angiogenic/growth factors in the tumor extracts was evaluated by membrane antibody array and collected tumor tissues were analyzed with histochemical staining. Melatonin in vitro treatment (1 mM) decreased cell viability (p<0.05). The breast cancer xenografts nude mice treated with melatonin showed reduced tumor size and cell proliferation (Ki-67) compared to control animals after 21 days of treatment (p<0.05). Expression of VEGF receptor 2 decreased significantly in the treated animals compared to that of control when determined by immunohistochemistry (p<0.05) but the changes were not significant on SPECT (p>0.05) images. In addition, there was a decrease of micro-vessel density (Von Willebrand Factor) in melatonin treated mice (p<0.05). However, semiquantitative densitometry analysis of membrane array indicated increased expression of epidermal growth factor receptor and insulin-like growth factor 1 in treated tumors compared to vehicle treated tumors (p<0.05). In conclusion, melatonin treatment showed effectiveness in reducing tumor growth and cell proliferation, as well as in the inhibition of angiogenesis.

Immunohistochemical investigation of the angiogenic proteins VEGF, HIF-1α and CD34 in invasive ductal carcinoma of the breast

The expression of prognostic markers in cancer has become important in diagnostic routine and research. A high mitotic rate compromises the individual cell access to oxygen and nutrients, due to reduced blood supply. Cells undertake adaptive measures such as vascular endothelial growth factor (VEGF), expressed under the control of hypoxia-inducible factor-1α (HIF-1α). CD34 is an endothelial marker which can show the presence and distribution of blood vessels. This study evaluated the presence and relative expression of VEGF, HIF-1α and CD34 using immunohistochemistry of 60 breast tumors and double staining, correlating the findings with clinical and pathological variables. High VEGF expression was correlated with low cell proliferation, lymph node-negative, smaller tumor size and patients not receiving hormone therapy. High HIF-1α expression predominated in younger (<50-year) patients, subjected to neo-adjuvant therapy and in p53-negative tumors. Absence of metastasis, radiotherapy or hormone treatment, and estrogen receptor (ER)-positive tumors showed high CD34 immunoreactivity. We suggest that the angiogenic factors VEGF, HIF-1α and CD34 are important in breast cancer progression and their abundance in breast tumors has prognostic and predictive value.

Abstract A009: Effect of melatonin on the tumor growth and angiogenesis of breast cancer

Background: Breast cancer has a high mortality rate, mainly due to tumor progression and metastatic spread. Once tumor lesion exceeds a few millimeters in diameter, hypoxia triggers a cascade of events to allow neovascularization. The major contributors to angiogenesis are the vascular endothelial growth factor (VEGF) and its receptors, which promote cell proliferation, migration, permeability and survival. Thus, controlling tumor-associated angiogenesis is a promising tactic in limiting cancer development. The melatonin administration, a hormone naturally produced and secreted in the pineal gland, appears to play an important oncostatic role in cancer and have been currently proposed different mechanisms of action. In this study we evaluated the benefits of melatonin treatment on tumor growth and angiogenesis in breast cancer.

Methods: MDA-MB-231 breast cancer cell line was cultured and cell viability was measured by MTT assay after incubation with different concentrations of melatonin (5 mM, 10 mM, 20 mM). We performed an in vivo study implanting cells in athymic nude mice. Mice were treated with 1mg of melatonin (n = 5) or vehicle (n = 8) daily, starting in the same day as tumor implantation and continued for 21 days. Tumors were measured with a digital caliper on day 7, 14 and 21 and the animals underwent SPECT scanning with Tc-99m tagged VEGF-c to detect in vivo angiogenesis (expression of VEGFR2/3). In addition, the markers of angiogenesis (VEGFR2, VEGFR3 and von Willebrand Factor (vWF)) and cell proliferation (Ki-67) were evaluated by immunohistochemistry in mammary tumor tissues.

Results: Melatonin treatment in vitro was able to significantly decrease cell viability, after 4 hours of exposure, maintaining its efficacy at higher doses after 24 hours exposure (p&lt;0.05). The animals treated with melatonin showed reduced tumor size compared to control animals after 21 days of treatment (p&lt;0.05). The mean tumor volume of control and treated animals were 282.00 ± 88.53 mm3 and 144.90 ± 38.38 mm3, respectively. The mean of tumor volume in control animals increased significantly from day 14 (118.90 ± 40.17 mm3) to day 21 (282.00 ± 88.53 mm3) (p&lt;0.05), which was not observed in the treated group. Furthermore, there was tumor regression in an animal treated with melatonin (Day 7 = 27.38 mm3; Day 14 = 8.79 mm3; Day 21 = 4.8 mm3), similar pattern was not seen in any of the control. Animals treated with melatonin showed lower activity of Tc-99-VEGF-C in the tumors compared to that of the animals that were treated with vehicle. The intensity of radioactivity in the control animals was 183.55 ± 20.92%, while the intensity of radioactivity in animals treated with melatonin was 150.46 ± 17.06%. Although there was difference in the radioactivity in the tumors between the two group, statistically significant difference was not achieved (p&gt;0.05). However, decrease of VEGFR2 in melatonin treated mice was confirmed by immunohistochemistry (p&lt;0.05). In addition, there was a decrease of micro-vessel density (vWF) and cell proliferation (Ki-67) in melatonin treated tumors (p&lt;0.05).

Conclusion: Taken together, our results showed that melatonin inhibits tumor growth, cell proliferation and blocks tumor angiogenesis in breast cancer, directing the development of a clinical study to determine its therapeutic potential for breast cancer.

Citation Format: Bruna Victorasso Jardim-Perassi, Ali S. Arbab, Lívia Carvalho Ferreira, Thaiz Ferraz Borin, Nadimpalli Ravi S. Varma, Adarsh Shankar, Asm Iskander, Meser M. Ali, Debora Aparecida Pires de Campos Zuccari. Effect of melatonin on the tumor growth and angiogenesis of breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr A009.

An immunohistochemical study of interleukin-8 (IL-8) in breast cancer

The use of prognostic markers for breast cancer is important for routine diagnosis and research. Interleukin-8 is a chemotactic cytokine produced by several cell types in response to inflammation, however, its expression, regulation and function are poorly understood. Recent studies have associated angiogenesis and inflammatory processes with tumor malignancy. The present study investigated the correlation between interleukin-8 expression and breast cancer prognosis. Interleukin-8 expression was assessed in 72 women with mammary neoplasia by immunohistochemistry and the results were statistically correlated with clinical-pathological findings. There was an inverse correlation between interleukin-8 expression and metastasis (p=0.03) and/or local recurrence (p=0.02). In the patient group that received post-surgery chemotherapy and radiotherapy, a lower interleukin-8 expression was found in those women that showed local recurrence (p=0.01). Multivariate logistic regression showed estrogen receptor negativity, progesterone positivity and metastasis with increased risk of death (p<0.05). The data reflect the complexity of the role of interleukin-8 in tumor microenvironment and support its classification as a possible prognostic marker, although more studies are necessary for its inclusion in clinical practice.

Response of angiogenic factors to the treatment with melatonin in breast cancer cell lines

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Background: Tumor growth and metastasis are the leading cause of death in breast cancer patients. The tumor growth requires neoangiogenesis, stimulated by vascular endothelial growth factor (VEGF) expressed under control of hypoxia-inducible factor-1α (HIF-1α). Melatonin, a natural hormone has been suggested as a new therapeutic agent to inhibit angiogenesis factors in several types of cancers. We evaluated the HIF-1α and VEGF expression in breast cancer cell line after hypoxia and treatment with melatonin. Methods: Breast cancer cell lines ER-positive (MCF-7) and ER-negative (MDA-MB-231) were cultured in DMEM at 37°C in 5% CO2. The cells were treated with CoCl2 to mimic hypoxia, and then treated with melatonin. Cell viability was measured by MTT assay with five melatonin concentrations (0.5mM, 1mM, 2mM, 5mM, 10mM). For the pharmacological concentration of melatonin (1mM) the protein and gene expression of HIF-1α and VEGF were detected by immunocytochemistry and real time PCR, respectively. Results: There was a significantly decrease in MCF-7 cells viability after treatment with all concentrations of melatonin and in MDA-MB-231 cells just with 1mM (p<0.05). The melatonin treatment did not alter the protein and gene expression of HIF-1α in MCF-7 cells (p>0.05), however, it significantly decreased the VEGF protein expression (p<0.05). In MDA-MB-231 cells there was significant decreased in the HIF-1α protein expression (p<0.05). Conclusions: Our results showed that 1mM of melatonin decreased the cell viability and HIF-1α protein expression in ER-negative cells, and VEGF protein expression in ER-positive cells. This study is the first that evaluated the expression of these angiogenic factors in breast cancer cells after treatment with melatonin that can be a potential therapeutic agent. Thus, we are performing in vivo study to confirm the potential effectiveness of melatonin in the control of angiogenesis in breast cancer.

Avaliação da caspase-3 e Ki-67 como marcadores prognósticos nas neoplasias mamárias em cadelas

A apoptose e a proliferação celular possuem uma participação importante na tumorigênese, determinando o crescimento tumoral e consequentemente sua agressividade. O presente estudo teve como objetivo avaliar a ocorrência da apoptose associada a proliferação celular em neoplasias mamárias em cadelas e a elas a evolução clínica do paciente. Setenta animais foram submetidos à exérese cirúrgica do tumor, sendo este submetido ao diagnóstico histopatológico e marcação imuno-histoquímica para caspase-3 e Ki-67. Estes marcadores de apoptose e proliferação celular demonstraram grande expressão nas neoplasias malignas, principalmente nos carcinomas, considerado o mais maligno dos tumores. Estes resultados corroboram os dados da literatura e contribuem para um prognóstico tumoral criterioso que complementa a classificação tumoral existente proporcionando uma melhor e maior sobrevida devido a uma adequação do procedimento terapêutico de cada paciente.