Unveiling the Anticarcinogenic Potential of Inula racemosa Hook. f. Root Extract Against DMBA-Induced Mammary Tumour in Sprague Dawley Rats.

The Himalayan plant Inula racemosa has medicinal properties and can be used to prevent or treat cancer. This is because it contains certain chemicals that are known to fight cancer cells with few or no side effects. I. racemosa has been used for this purpose for many years in traditional medicine and has shown promising results. The present study was crafted to explore the suppressive impacts on cellular proliferation of the root extract derived from I. racemosa via in vivo experimentation. I. racemosa (IR) root extract was tested at three different doses (100, 250, and 500 mg/Kg BW) for 18 weeks to assess its anti-neoplastic activity against mammary tumors in female rats. The assessment included various parameters such as hematological and biochemical indices, tumor parameters, oxidative stress analysis, gross and histopathological lesion determination, Masson's trichrome staining, immunohistochemical expression of Ki-67, MMP-9, and VEGF in mammary gland tissues, and molecular docking. The chemopreventive action of IR root extract was demonstrated by the inhibition of tumor parameters (tumor size and tumor volume), minimum changes in the liver (ALT, AST, and ALP) and kidney enzymes (BUN and creatinine), declined lipid peroxidation activity, decline gross, and histological changes in mammary gland tumors, reduced expression of KI-67, MMP-9, and VEGF and maximum binding affinity of isoalantolactone with VEGF through molecular docking. The study suggests that the active constituents (isoalantolactone and alantolactone) of I. racemosa roots have anti-neoplastic activity against mammary tumors, making them a valuable therapeutic regimen for the future.

Promoting effect of sunset yellow on N-methyl N-nitrosourea-induced rat mammary carcinogenesis: Implications of molecular mechanisms.

BACKGROUND: Nowadays, the use of food additives, such as Sunset Yellow (SY), is growing, which attracted attention to the potential relationship between some diseases and food additives. AIM: The study aimed to investigate the role of Sunset Yellow during chemically-induced mammary gland carcinogenesis in Sprague-Dawley rats. MATERIAL AND METHODS: Three groups of female rats were intraperitoneally administered with N-methyl-N-nitrosourea (MNU). Group 1 was set on a basal diet. Group 2 was treated with 161.4 mg\kg\day Sunset Yellow (SY). Group 3 was given SY at 80.7 mg\kg\day. Groups 4-6 were not administered MNU; Group 4 received vehicles only. Groups 5 and 6 were administered SY similarly to groups 2 and 3 respectively. RESULTS: Sunset Yellow at both doses exerted a significant dose-dependent increase in tumor incidences, multiplicities, volumes, and decreased tumor latency as compared with control. Immunolabeling indexes of the proliferating cell nuclear antigen, estrogen receptor alpha, and progesterone receptor were significantly increased after SY treatment. Oxidative stress markers, serum estrogen, progesterone, and prolactin levels were significantly modified by SY treatment. The mRNA expression of estrogen receptor alpha and epidermal growth factor was up-regulated in SY groups versus control. CONCLUSION: Collectively, SY has significantly promoted MNU-induced mammary tumors in rats with underlying mechanisms correlating SY consumption with estrogen disruption and subsequent antioxidative stress discrepancy.

TGFß in malignant canine mammary tumors: relation with angiogenesis, immunologic markers and prognostic role.

Transforming growth factor-ß (TGFß) and FoxP3 regulatory T cells (Treg) are involved in human breast carcinogenesis. This topic is not well documented in canine mammary tumors (CMT). In this work, the tumoral TGFß expression was assessed by immunohistochemistry in 67 malignant CMT and its correlation to previously determined FoxP3, VEGF, and CD31 markers and other clinicopathologic parameters was evaluated. The high levels of TGFß were statistically significantly associated with skin ulceration, tumor necrosis, high histological grade of malignancy (HGM), presence of neoplastic intravascular emboli and presence of lymph node metastases. The observed levels of TGFß were positively correlated with intratumoral FoxP3 (strong correlation), VEGF (weak correlation) and CD31 (moderate correlation). Tumors that presented a concurrent high expression of TGFß/FoxP3, TGFß/VEGF, and TGFß/CD31 markers were statistically significantly associated with parameters of tumor malignancy (high HGM, presence of vascular emboli and nodal metastasis). Additionally, shorter overall survival (OS) time was statistically significantly associated with tumors with an abundant TGFß expression and with concurrent high expression of TGFß/FoxP3, TGFß/VEGF, and TGFß/CD31. The presence of lymph node metastasis increased 11 times the risk of disease-related death, arising as an independent predictor of poor prognosis in the multivariable analysis. In conclusion, TGFß and Treg cells seem involved in tumor progression emerging as potential therapeutic targets for future immunotherapy studies.

Exploring the role of microRNAs as diagnostic and prognostic biomarkers in canine mammary tumors.

Canine mammary tumors (CMTs) represent a significant health concern in dogs, with a high incidence among intact female dogs. CMTs are a promising comparative model for human breast cancer, due to sharing several pathophysiological features. Additionally, CMTs have a strong genetic correlation with their human counterpart, including the expression of microRNAs (miRNAs). MiRNAs are a class of non-coding RNAs that play important roles in post-translational regulation of gene expression, being implicated in carcinogenesis, tumor progression, and metastasis. Moreover, miRNAs hold promise as diagnostic, prognostic, and metastatic biomarkers. Understanding the molecular mechanisms underlying CMTs is crucial for improving diagnosis, prognosis, and monitoring of treatments. Herein, we provide a comprehensive overview of the current knowledge on miRNAs in CMTs, highlighting their roles in carcinogenesis and their potential as biomarkers. Additionally, we highlight the current limitations and critically discuss the overarching challenges in this field, emphasizing the need for future research to translate miRNA findings into veterinary clinical practice.

Benzo[a]pyrene promotes an epithelial-to-mesenchymal transition process in MCF10A cells and mammary tumor growth and brain metastasis in female mice.

Breast cancer is the most frequent neoplasia in developed countries and the leading cause of death in women worldwide. Epithelial-to-mesenchymal transition (EMT) is a cellular process through which epithelial cells decrease or lose their epithelial characteristics and gain mesenchymal properties. EMT mediates tumor progression, because tumor cells acquire the capacity to execute the multiple steps of invasion and metastasis. Benzo[a]pyrene (B[a]P) is an environmental organic pollutant generated during the burning of fossil fuels, wood, and other organic materials. B[a]P exposition increases the incidence of breast cancer, and induces migration and/or invasion in MDA-MB-231 and MCF-7 breast cancer cells. However, the role of B[a]P in the induction of an EMT process and metastasis of mammary carcinoma cells has not been studied in detail. In this study, we demonstrate that B[a]P induces an EMT process in MCF10A mammary non-tumorigenic epithelial cells. In addition, B[a]P promotes the formation of larger tumors in Balb/cJ mice inoculated with 4T1 cells than in untreated mice and treated with dimethyl sulfoxide (DMSO). B[a]P also increases the number of mice with metastasis to brain and the total number of brain metastatic nodules in Balb/cJ mice inoculated with 4T1 cells compared with untreated mice and treated with DMSO. In conclusion, B[a]P induces an EMT process in MCF10A cells and the growth of mammary tumors and metastasis to brain in Balb/cJ mice inoculated with 4T1 cells.

Pirfenidone ameliorates alcohol-induced promotion of breast cancer in mice.

Purpose: Alcohol consumption increases the risk of breast cancer and promotes cancer progression. Alcohol exposure could affect both processes of the mammary carcinogenesis, namely, the cell transformation and onset of tumorigenesis as well as cancer aggressiveness including metastasis and drug resistance/recurrence. However, the cellular and molecular mechanisms underlying alcohol tumor promotion remain unclear. There are four members of the mammalian p38 mitogen-activated protein kinase (MAPK) family, namely, p38α, p38ß, p38γ and p38δ. We have previously demonstrated alcohol exposure selectively activated p38γ MAPK in breast cancer cells in vitro and in vivo. Pirfenidone (PFD), an antifibrotic compound approved for the treatment of idiopathic pulmonary fibrosis, is also a pharmacological inhibitor of p38γ MAPK. This study aimed to determine whether PFD is useful to inhibit alcohol-induced promotion of breast cancer. Methods: Female adolescent (5 weeks) MMTV-Wnt1 mice were exposed to alcohol with a liquid diet containing 6.7% ethanol. Some mice received intraperitoneal (IP) injection of PFD (100 mg/kg) every other day. After that, the effects of alcohol and PFD on mammary tumorigenesis and metastasis were examined. Results: Alcohol promoted the progression of mammary tumors in adolescent MMTV-Wnt1 mice. Treatment of PFD blocked tumor growth and alcohol-promoted metastasis. It also significantly inhibited alcohol-induced tumorsphere formation and cancer stem cell (CSC) population. Conclusion: PFD inhibited mammary tumor growth and alcohol-promoted metastasis. Since PFD is an FDA-approved drug, the current findings may be helpful to re-purpose its application in treating aggressive breast cancer and alcohol-promoted mammary tumor progression.

The NDV-MLS as an Immunotherapeutic Strategy for Breast Cancer: Proof of Concept in Female Companion Dogs with Spontaneous Mammary Cancer.

The absence of tumor-infiltrating lymphocytes negatively impacts the response to chemotherapy and prognosis in all subtypes of breast cancer. Therapies that stimulate a proinflammatory environment may help improve the response to standard treatments and also to immunotherapies such as checkpoint inhibitors. Newcastle disease virus (NDV) shows oncolytic activity, as well as immune modulating potential, in the treatment of breast cancer in vitro and in vivo; however, its potential to enhance tumor-infiltrating immune cells in breast cancer has yet to be evaluated. Since spontaneous canine mammary tumors represent a translational model of human breast cancer, we conducted this proof-of-concept study, which could provide a rationale for further investigating NDV-MLS as immunotherapy for mammary cancer. Six female companion dogs with spontaneous mammary cancer received a single intravenous and intratumoral injection of oncolytic NDV-MLS. Immune cell infiltrates were evaluated by histology and immunohistochemistry in the stromal, intratumoral, and peritumoral compartments on day 6 after viral administration. Increasing numbers of immune cells were documented post-viral treatment, mainly in the peritumoral compartment, where plasma cells and CD3+ and CD3-/CD79- lymphocytes predominated. Viral administration was well tolerated, with no significant adverse events. These findings support additional research on the use of NDV-MLS immunotherapy for mammary cancer.

Machine learning determines stemness associated with simple and basal-like canine mammary carcinomas.

Simple and complex carcinomas are the most common type of malignant Canine Mammary Tumors (CMTs), with simple carcinomas exhibiting aggressive behavior and poorer prognostic. Stemness is an ability associated with cancer initiation, malignancy, and therapeutic resistance, but is still few elucidated in canine mammary tumor subtypes. Here, we first validated, using CMT samples, a previously published canine one-class logistic regression machine learning algorithm (OCLR) to predict stemness (mRNAsi) in canine cancer cells. Then, using the canine mRNAsi, we observed that simple carcinomas exhibit higher stemness than complex carcinomas and other histological subtypes. Also, we confirmed that stemness is higher and associated with basal-like CMTs and with NMF2 metagene signature, a tumor-specific DNA-repair metagene signature. Using correlation analysis, we selected the top 50 genes correlated with higher stemness, and the top 50 genes correlated with lower stemness and further performed a gene set enrichment analysis to observe the biological processes enriched for these genes. Finally, we suggested two promise stemness-associated targets in CMTs, POLA2 and APEX1, especially in simple carcinomas. Thus, our work elucidates stemness as a potential mechanism behind the aggressiveness and development of canine mammary tumors, especially in simple carcinomas, describing evidence of a promising strategy to target this disease.

Immunohistochemical Expression and Prognostic Value of COX-2 and Alpha-Smooth Muscle Actin-positive Cancer-associated Fibroblasts in Feline Mammary Cancer.

BACKGROUND: Cyclo-oxygenase-2 (COX-2) and cancer associated fibroblasts (CAFs) play an important role in the development and progression of tumor malignancy in humans and animals, showing that both can influence the tumor microenvironment. However, the impact of these two markers in feline mammary carcinogenesis has not yet been addressed. MATERIALS AND METHODS: In the present study, the clinicopathological significance of COX-2 immunoexpression and alpha-smooth muscle actin (α-SMA)-positive cancer-associated fibroblasts (CAFs) was determined and correlated with disease-free and overall survival of 50 felines with malignant mammary tumors. RESULTS: COX-2 overexpression was positively associated with mitotic index (p=0.031), degree of malignancy (p≤0.001), lymph node metastasis (p≤0.001), vascular invasion (p=0.002), disease recurrence (p=0.019) and distant metastasis (p=0.036). α-SMA-positive CAFs were associated with mitotic index (p=0.004), lymph node metastasis (p=0.027), vascular invasion (p=0.05), disease recurrence (p≤0.001) and distant metastasis (p≤0.001). Additionally, both markers were correlated with disease-free and overall survival, emerging as predictors of poor prognosis. CONCLUSION: Our results indicate for the first time that the presence of two markers, COX-2 and α-SMA, is associated with carcinogenesis and worse prognosis in feline mammary cancer and that α-SMA-positive CAFs have a role in feline mammary tumorigenesis, cancer development, and clinical outcome.

Profiling canine mammary tumors: A potential model for studying human breast cancer.

Despite all clinical progress recorded in the last decades, human breast cancer (HBC) remains a major challenge worldwide both in terms of its incidence and its management. Canine mammary tumors (CMTs) share similarities with HBC and represent an alternative model for HBC. The utility of the canine model in studying HBC relies on their common features, include spontaneous development, subtype classification, mutational profile, alterations in gene expression profile, and incidence/prevalence. This review describes the similarities between CMTs and HBC regarding genomic landscape, microRNA expression alteration, methylation, and metabolomic changes occurring during mammary gland carcinogenesis. The primary purpose of this review is to highlight the advantages of using the canine model as a translational animal model for HBC research and to investigate the challenges and limitations of this approach.

Maduramicin-guided nanotherapy: A polymeric micelles for targeted drug delivery in canine mammary tumors.

Canine mammary tumors (CMT) can severely compromise the life quality of the affected dogs through local recurrence, distant metastases and ultimately succumb to death. Recently, more attention has been given to the potential antimetastatic effect of maduramicin (MAD) on breast cancer. However, its poor aqueous solubility and toxicity to normal tissues limit its clinical application. Therefore, to address the drawbacks of MAD and enhance its anticancer and antimetastatic effects, MAD-loaded TPGS polymeric micelles (MAD-TPGS) were prepared by a thin-film hydration technique. The optimized MAD-TPGS exhibited excellent size distribution, stability and improved water solubility. Cellular uptake assays showed that TPGS polymer micelles could enhance drug internalization. Moreover, TPGS synergistically improved the cytotoxicity of MAD by targeting mitochondrial organelles, improving reactive oxygen species levels and reducing the mitochondrial transmembrane potential. More importantly, MAD-TPGS significantly impeded the metastasis of tumor cells. In vivo results further confirmed that, in addition to exhibiting excellent biocompatibility, MAD-TPGS exhibited greater antitumor efficacy than free MAD. Interestingly, MAD-TPGS displayed superior suppression of CMT metastasis via tail vein injection compared to oral administration, indicating its suitability for intravenous delivery. Overall, MAD-TPGS could be applied as a potential antimetastatic cancer agent for CMT.

Antitumor Effect of Berberine Analogs in a Canine Mammary Tumor Cell Line and in Zebrafish Reporters via Wnt/ß-Catenin and Hippo Pathways.

The heterogeneous nature of human breast cancer (HBC) can still lead to therapy inefficacy and high lethality, and new therapeutics as well as new spontaneous animal models are needed to benefit translational HBC research. Dogs are primarily investigated since they spontaneously develop tumors that share many features with human cancers. In recent years, different natural phytochemicals including berberine, a plant alkaloid, have been reported to have antiproliferative activity in vitro in human cancers and rodent animal models. In this study, we report the antiproliferative activity and mechanism of action of berberine, its active metabolite berberrubine, and eight analogs, on a canine mammary carcinoma cell line and in transgenic zebrafish models. We demonstrate both in vitro and in vivo the significant effects of specific analogs on cell viability via the induction of apoptosis, also identifying their role in inhibiting the Wnt/ß-catenin pathway and activating the Hippo signals with a downstream reduction in CTGF expression. In particular, the berberine analogs NAX035 and NAX057 show the highest therapeutic efficacy, deserving further analyses to elucidate their mechanism of action more in detail, and in vivo studies on spontaneous neoplastic diseases are needed, aiming at improving veterinary treatments of cancer as well as translational cancer research.

Doxorubicin as a Potential Treatment Option in Canine Mammary Tumors.

Canine mammary tumors represent one of the leading malignant pathologies in female dogs, displaying the importance of efficient therapeutic findings, besides the golden-standard surgery, able to limit the development of the disease. Studies in human cancers demonstrated that Doxorubicin presents a good effect in different biological processes like apoptosis, autophagy, the cell cycle, cell invasion, and the epithelial-to-mesenchymal transition. This study followed the effects of Doxorubicin on two canine mammary cancer cell lines P114 and CMT-U27. Doxorubicin treatment in both cell lines shows an inhibitory effect in cell proliferation and an alteration in expression of the EMT-related genes. The obtained results provide valuable information for revealing the link between Doxorubicin, phenotypic changes, and proliferation dynamics in canine mammary tumor models.

Platelet count and MCHC as independent prognostic markers for feline mammary carcinomas.

Mammary neoplasms are common in felines species and represent a significant disease for its unfavorable prognosis. Changes in the blood count and serum biochemical profile of these patients have potential as non-invasive prognostic markers prior to mastectomy, however, they are poorly described in literature. In this study univariate and multivariate analyses were performed using these factors to determine the effect of each parameter on the one-year survival time after the surgical procedure in these animals. The median overall survival (OS) and the disease-free survival (DFS) were 365 and 242 days, respectively. In univariate analysis, values within the reference range of monocyte, platelet and creatinine counts were identified as significant prognostic factors for OS and only creatinine was significant for DFS (P < 0.05). In the multivariate analysis, platelets and mean corpuscular hemoglobin concentration (MCHC) remained independent prognostic factors for OS. The results presented suggest that monocytes, platelets and creatinine may be important non-invasive pre-surgical prognostic markers, and that platelet count and MCHC are independent prognostic markers for feline mammary carcinomas (FMC). The correlation between such alterations is of important relevance for veterinary oncology, and prospective studies are needed to validate their clinical use and that platelet count and MCHC are independent prognostic markers for FMC. The results found in this study can also be studied in human medicine, regarding blood markers in human breast cancer (HBC).

Identifying the Risk Factors for Malignant Mammary Tumors in Dogs: A Retrospective Study.

Mammary cancer is one of the main causes of death in female dogs worldwide, considering that many risk factors are involved in its development. This study aimed to elucidate the relationship between epidemiological and clinical risk factors with the histopathological diagnosis of malignant mammary tumors in dogs treated at the Veterinary Hospital of the Federal University of Uberlândia, which has one of the first veterinary oncology services in Brazil. A retrospective matched case-control study was conducted to identify risk factors for the development of malignant mammary tumors in dogs. The variables analyzed were size dog, breed, housing, type of diet, and body score. Potential risk factors were selected by univariate analysis (p < 0.25) before multivariate forward binary logistic regression. The most frequent benign tumor was the benign mixed tumor (35.2%), and the most frequent malignant tumor was the mixed carcinoma (27.4%). Size dog, breed, housing, and overweight are predictors of malignant mammary tumors in dogs. The highest risk of developing malignant mammary tumors is associated with large female dogs, Yorkshire or Poodle breeds, living outside the home, or being overweight.

Placental and Breast Metastasis of Squamous Cell Carcinoma in a Patient With Recurrent Respiratory Papillomatosis.

Recurrent respiratory papillomatosis (RRP), which is usually benign, is an intractable disease characterized by recurrent papillomas (wart-like lesions). Although it most commonly involves the mucosal epithelial lining of the upper respiratory tract, on rare occasions, it can also involve lung parenchyma. RRP carries the risk of malignant transformation, most often to non-small-cell squamous lung cancer. Here, we present the case of a 32-year-old pregnant female with a past medical history of RRP who developed mild respiratory distress during her immediate postpartum period. This prompted imaging of the chest which revealed right lower lobe hypodensities with extensive hilar and perihilar lymphadenopathy. Histopathology of the bronchial specimen showed squamous cell carcinoma with 100% programmed death-ligand 1 (PD-L1) expression. Gross examination of the patient's placenta showed multiple tan-colored nodules which was confirmed on histopathological examination as multifocal regions of squamous cell carcinoma metastatic from the lung. The patient underwent a staging positron emission tomography (PET) scan which showed hypermetabolic regions in the right middle and lower lobes of the lung, with avidity in the right paratracheal region and an enhancing lesion in the left breast. Biopsy from the breast lesion was also positive for squamous cell carcinoma and PD-L1. She was diagnosed with Stage IVB (T1c, N3, M1c) non-small-cell squamous lung cancer and was started on pembrolizumab. Carboplatin and paclitaxel were added after an initial mixed response to therapy. The patient was non-compliant with her updated treatment regimen as well as with outpatient follow-up visits. A restaging PET scan demonstrated an inadequate response to the amended immunotherapy/chemotherapy regimen. Ultimately, she passed away within one and a half years of her initial diagnosis. Malignant transformation of papillomatous lesions into squamous cell cancer is infrequent, and the occurrence of metastasis to the breast and/or placenta is exceptionally rare. To our knowledge, this is the first reported case of placental and breast metastasis of squamous cell lung cancer in a patient with RRP.

Metabolic Alterations in Canine Mammary Tumors.

Canine mammary tumors (CMTs) are among the most common diseases in female dogs and share similarities with human breast cancer, which makes these animals a model for comparative oncology studies. In these tumors, metabolic reprogramming is known as a hallmark of carcinogenesis whereby cells undergo adjustments to meet the high bioenergetic and biosynthetic demands of rapidly proliferating cells. However, such alterations are also vulnerabilities that may serve as a therapeutic strategy, which has mostly been tested in human clinical trials but is poorly explored in CMTs. In this dedicated review, we compiled the metabolic changes described for CMTs, emphasizing the metabolism of carbohydrates, amino acids, lipids, and mitochondrial functions. We observed key factors associated with the presence and aggressiveness of CMTs, such as an increase in glucose uptake followed by enhanced anaerobic glycolysis via the upregulation of glycolytic enzymes, changes in glutamine catabolism due to the overexpression of glutaminases, increased fatty acid oxidation, and distinct effects depending on lipid saturation, in addition to mitochondrial DNA, which is a hotspot for mutations. Therefore, more attention should be paid to this topic given that targeting metabolic fragilities could improve the outcome of CMTs.

Upregulation of miR-21 and pro-inflammatory cytokine genes IL-6 and TNF-α in promoting a pro-tumorigenic microenvironment in canine mammary carcinomas.

This study evaluated the gene expression of the pro-inflammatory cytokines, interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in canine mammary tumors (CMTs), and correlated them with gene expression of miRNAs expected to regulate the secretion of pro-inflammatory cytokines within the tumor microenvironment (TME). Furthermore, gene expression of cytokines and miRNAs involved in tumor cell proliferation and invasion (i.e. miR-21; miR-124; miR-145) were correlated with tumor proliferation index (Ki67 index) to determine the prognostic value in CMTs. Twenty-six canine mammary samples were used, including 22 CMTs and 4 control samples. MiR-21, IL-6 and TNF-α were upregulated in mammary carcinomas compared with controls (p < 0.05). MiR-146b was downregulated in CMTs compared with control cases (p < 0.05). IL-6 expression showed a significant positive correlation with miR-21 and a negative correlation with miR-146b; while, TNF-α gene expression was positively correlated with miR-21 and miR-145 in mammary carcinomas. In carcinomas, the Ki67 index correlated positively with gene expression of IL-6 and miR-21 and negatively correlated with miR-145 and miR-146b. Specifically, gene expression of IL-6 and miR-21 was positively correlated with ki67 index >33.3%, whereas, expression of miR-145 and miR-146b was negatively correlated with ki67 index <33.3%. Results reinforce the concept of interaction between tumor cells and inflammatory cells within the TME, with a central role of IL-6 and TNF-α. Since the upregulation of miR-21 reflects the gene overexpression of interleukins and the high proliferation index of tumor cells, this miRNA may be considered a biomarker with prognostic value in CMTs.

Sirtuin 1 Expression in Canine Mammary Tumors: A Pilot Study.

Sirtuin 1 (SIRT1) is a protein involved in aging, cell protection, and energy metabolism in mammals. Recently, SIRT1 has been intensively studied in medical oncology, but the role of SIRT1 is still controversial, as it has been proposed as both an oncogene and a tumor suppressor. The aim of this study is to investigate the expression of SIRT1 by immunohistochemistry in canine mammary tissues, and by Western blot and immunofluorescence analysis in different canine mammary cell lines. Our results showed a decrease in SIRT1 expression from normal mammary gland tissue, and from benign and well-differentiated malignant tumors (G1) to less differentiated ones (G2-G3). Furthermore, a shift in the subcellular localization of SIRT1 from the nucleus to the cytoplasm was observed in less differentiated malignant tumors. However, further studies are needed to investigate the subcellular localization of SIRT1 in canine cancer cells and the role it may play in oncogenesis in animals.

Safety of lactational exposure to venlafaxine on the rat mammary gland development and carcinogenesis in F1 female offspring.

The chronic use of selective serotonin reuptake inhibitors or serotonin-norepinephrine reuptake inhibitors (SNRIs) may result in human gynecomastia, mammoplasia, galactorrhea, and elevated breast cancer risk. As antidepressants are frequently used for postpartum depression (PPD) treatment, this study investigated the adverse effects of lactational exposure to venlafaxine (VENL, a selective SNRI) on mammary gland development and carcinogenesis in F1 female offspring. Thus, lactating Wistar rats (F0) received VENL by oral gavage at daily doses of 3.85, 7.7, or 15.4 mg/kg (N = 9, each group) from lactational day (LD 1) until the weaning of the offspring (LD 21). F1 female offspring were euthanized for mammary gland, and ovary histological analyses on the post-natal day (PND) 22 and 30 (1 pup/litter/period, N = 9, each group). At PND 22, other females (2 pups/litter, N = 18, each group) received a single dose of carcinogen N-methyl-N-nitrosourea (MNU, 50 mg/kg) intraperitoneally (i.p.) for tumor susceptibility assay until PND 250. Tumor incidence and latency were recorded and representative tumor samples were collected for histopathology. The results indicate that lactational exposure to VENL did not alter the development of the mammary gland (epithelial ductal tree or the mean number of terminal end buds), or the ovary (weight and primary, secondary, tertiary, and Graafian follicles) in prepubertal F1 female offspring. In addition, VENL exposure did not influence tumor incidence or tumor latency in adult female offspring that received MNU. Thus, the findings of this animal study indicated that lactational VENL exposure, a period similar to human PPD, did not exert an adverse effect on the mammary gland development at the prepubertal phase or on chemically induced mammary tumorigenesis in adult F1 female rats.