Oral low dose and topical tamoxifen for breast cancer prevention: modern approaches for an old drug

Therapeutic effect of topical tamoxifen in murine cutaneous leishmaniasis caused by Leishmania major

Iran is one of the endemic regions of cutaneous leishmaniasis (CL) caused by Leishmania major. There is no protective vaccine available against CL available, and the most effective strategy is a definitive treatment. Topical medications can be an excellent option for this purpose. Tamoxifen, a cancer control drug, has properties such as inducing cell apoptosis and anti-parasitic activity, which can be useful in controlling eukaryotic parasites such as Leishmania. The present study was conducted to investigate this theory in experimental CL caused by L. major. Forty female BALB/c mice aged 4 to 6 weeks were infected by injecting 1 × 106 L. major metacyclics (MRHO/IR/75/ER) in the base of the tail. After the appearance of Leishmania nodules, mice were divided into five test and control groups. Two drug formulations were used: tamoxifen 1% in ethanol and tamoxifen citrate ointment 0.1%. The effectiveness of each formula was evaluated by determining the mean size of the ulcers and parasite burden after a 28-day treatment period. Both formulations showed reduced ulcer mean sizes. However, only the tamoxifen citrate ointment group demonstrated a statistically significant reduction (P = 0.049). The parasite burden decreased by 40.83% for the ointment group and 33.67% for the ethanol solution. Other control groups showed lesser reductions. This study partially demonstrated the effectiveness of topical tamoxifen on CL lesions in a murine model. It can provide a basis for further research on the therapeutic effects of different topical tamoxifen formulations.

Bioconjugates for Cancer Prevention: Opportunities for Impact

Cancer prevention encompasses both screening strategies to find cancers early when they are likely to be most treatable and prevention and interception strategies to reduce the risk of developing cancers. Bioconjugates, here defined broadly as materials and molecules that have synthetic and biological components, have roles to play across the cancer-prevention spectrum. In particular, bioconjugates may be developed as affordable, accessible, and effective screening strategies or as novel vaccines and drugs to reduce one's risk of developing cancers. Developmental programs are available for taking novel technologies and evaluating them for clinical use in cancer screening and prevention. While a variety of different challenges exist in implementing cancer-prevention interventions, a thoughtful approach to bioconjugates could improve the delivery and acceptability of the interventions.

Gynotoxic Effects of Chemotherapy and Potential Protective Mechanisms

Chemotherapy is one of the leading cancer treatments. Unfortunately, its use can contribute to several side effects, including gynotoxic effects in women. Ovarian reserve suppression and estrogen deficiency result in reduced quality of life for cancer patients and are frequently the cause of infertility and early menopause. Classic alkylating cytostatics are among the most toxic chemotherapeutics in this regard. They cause DNA damage in ovarian follicles and the cells they contain, and they can also induce oxidative stress or affect numerous signaling pathways. In vitro tests, animal models, and a few studies among women have investigated the effects of various agents on the protection of the ovarian reserve during classic chemotherapy. In this review article, we focused on the possible beneficial effects of selected hormones (anti-Müllerian hormone, ghrelin, luteinizing hormone, melatonin), agents affecting the activity of apoptotic pathways and modulating gene expression (C1P, S1P, microRNA), and several natural (quercetin, rapamycin, resveratrol) and synthetic compounds (bortezomib, dexrazoxane, goserelin, gonadoliberin analogs, imatinib, metformin, tamoxifen) in preventing gynotoxic effects induced by commonly used cytostatics. The presented line of research appears to provide a promising strategy for protecting and/or improving the ovarian reserve in the studied group of cancer patients. However, well-designed clinical trials are needed to unequivocally assess the effects of these agents on improving hormonal function and fertility in women treated with ovotoxic anticancer drugs.

Dysregulation of deubiquitination in breast cancer

Breast cancer (BC) is a highly frequent malignant tumor that poses a serious threat to women's health and has different molecular subtypes, histological subtypes, and biological features, which act by activating oncogenic factors and suppressing cancer inhibitors. The ubiquitin-proteasome system (UPS) is the main process contributing to protein degradation, and deubiquitinases (DUBs) are reverse enzymes that counteract this process. There is growing evidence that dysregulation of DUBs is involved in the occurrence of BC. Herein, we review recent research findings in BC-associated DUBs, describe their nature, classification, and functions, and discuss the potential mechanisms of DUB-related dysregulation in BC. Furthermore, we present the successful treatment of malignant cancer with DUB inhibitors, as well as analyzing the status of targeting aberrant DUBs in BC.

Preparation and in Vitro Evaluation of Tamoxifen-Conjugated, Eco-Friendly, Agar-Based Hybrid Magnetic Nanoparticles for Their Potential Use in Breast Cancer Treatment

Tamoxifen is the drug of choice as hormonal therapy for hormone receptor-positive breast cancers and can reduce the risk of breast cancer recurrence. However, oral tamoxifen has a low bioavailability due to liver and intestinal metabolic passes. To overcome this problem and utilize the potential of this drug to its maximum, inorganic nanoparticle carriers have been exploited and tested to increase its bioavailability. Biocompatibility and unique magnetic properties make iron oxide nanoparticles an excellent choice as a drug delivery system. In this study, we developed and tested a "green synthesis" approach to synthesize iron nanoparticles from green tea extract and coated them with agar for longer stability (AG-INPs). Later, these hybrid nanoparticles were conjugated with tamoxifen (TMX). By using this approach, we synthesized stable agar-coated tamoxifen-conjugated iron nanoparticles (TMX-AG-INPs) and characterized them with Fourier-transform infrared (FTIR) spectroscopy. The average particle size of AG-INPs was 26.8 nm, while the average particle size of tamoxifen-loaded iron nanoparticles, TMX-AG-INPs, was 32.1 nm, as measured by transmission and scanning electron microscopy. The entrapment efficiency of TMX-AG-INPs obtained by the drug release profile was 88%, with a drug loading capacity of 43.5%. TMX-AG-INPs were significantly (p < 0.001) efficient in killing breast cancer cells when tested in vitro on the established breast cancer cell line MCF-7 by cell viability assay, indicating their potential to control cell proliferation.

Contributions of nanotechnology to the intraductal drug delivery for local treatment and prevention of breast cancer

Breast cancer is a major public health problem, affecting millions of people. It is a very heterogeneous disease, with localized and invasive forms, and treatment generally consists of a combination of surgery and radiotherapy followed by administration of estrogen receptor modulators or aromatase inhibitors. Given its heterogeneity, management strategies that take into consideration the type of disease and biological markers and can provide more personalized and local treatment are required. More recently, the intraductal administration (i.e., into the breast ducts) of drugs has attracted significant attention due to its ability of providing drug distribution through the ductal tree in a minimally invasive manner. Although promising, intraductal administration is not trivial, and difficulties in duct identification and cannulation are important challenges to the further development of this route. New drug delivery strategies such as nanostructured systems can help to achieve the full benefits of the route due to the possibility of prolonging tissue retention, improving targeting and selectivity, increasing cytotoxicity and reducing the frequency of administration. This review aims at discussing the potential benefits and challenges of intraductal administration, focusing on the design and use of nanocarriers as innovative and feasible strategies for local breast cancer therapy and prevention.

Tamoxifen Modulates the Immune Landscape of the Tumour Microenvironment: The Paired Siglec-5/14 Checkpoint in Anti-Tumour Immunity in an In Vitro Model of Breast Cancer

Since the role of sialome–Siglec axis has been described as a regulatory checkpoint of immune homeostasis, the promotion of stimulatory or inhibitory Siglec-related mechanisms is crucial in cancer progression and therapy. Here, we investigated the effect of tamoxifen on the sialic acid–Siglec interplay and its significance in immune conversion in breast cancer. To mimic the tumour microenvironment, we used oestrogen-dependent or oestrogen-independent breast cancer cells/THP-1 monocytes transwell co-cultures exposed to tamoxifen and/or β-estradiol. We found changes in the cytokine profiles accompanied by immune phenotype switching, as measured by the expression of arginase-1. The immunomodulatory effects of tamoxifen in THP-1 cells occurred with the altered SIGLEC5 and SIGLEC14 genes and the expression of their products, as confirmed by RT-PCR and flow cytometry. Additionally, exposure to tamoxifen increased the binding of Siglec-5 and Siglec-14 fusion proteins to breast cancer cells; however, these effects appeared to be unassociated with oestrogen dependency. Our results suggest that tamoxifen-induced alterations in the immune activity of breast cancer reflect a crosstalk between the Siglec-expressing cells and the tumour’s sialome. Given the distribution of Siglec-5/14, the expression profile of inhibitory and activatory Siglecs in breast cancer patients may be useful in the verification of therapeutic strategies and predicting the tumour’s behaviour and the patient’s overall survival.

Design, development and evaluation of Resveratrol transdermal patches for breast cancer therapy

Resveratrol (RVT) is a polyphenolic phytoestrogen which has shown antiproliferative activity in breast cancer. However, its low bioavailability and short half-life have restricted its use. The current study aimed to develop transdermal patches of RVT and evaluate its site-specific delivery for breast cancer therapy. Different penetration enhancers were screened using a computational tool, quantitative structure propery relationship (QSPR). The best permeation of RVT was observed in a patch comprising hydroxypropyl methylcellulose (HPMC) E15LV: HPMC-K4M: polyvinyl pyrrolidone (PVP) K30 in the ratio of 3:1:2 as release controlling polymers with Glycerol:Capryol 90 (4:1) as penetration enhancer and plasticizer. To assess the localized delivery of RVT, the patch was applied to the breast of female rats. Higher breast tissue disposition with lower systemic concentration was observed compared to oral administration, demonstrated by increased AUC and MRT. Further, the optimized RVT patches were tested in 7,12-Dimethylbenz[a]anthracene (DMBA) induced rat mammary cancer. Compared to oral RVT, the application of RVT tansdermal patches significantly reduced the tumor volume and serum CA 15-3, a cancer biomarker. Thus, the RVT transdermal patch may be a viable approach for ensuring high local concentration of drug for site-specific delivery in breast cancer therapy.

Patient and Provider Web-Based Decision Support for Breast Cancer Chemoprevention: A Randomized Controlled Trial

Significant underutilization of breast cancer chemoprevention remains, despite guidelines stating that physicians should recommend chemoprevention with antiestrogen therapy to high-risk women. We randomized women, ages 35 to 75 years, who met high-risk criteria for breast cancer, without a personal history of breast cancer or prior chemoprevention use, to standard educational materials alone or combined with a web-based decision aid. All healthcare providers, including primary care providers and breast specialists, were given access to a web-based decision support tool. The primary endpoint was chemoprevention uptake at 6 months. Secondary outcomes included decision antecedents (perceived breast cancer risk/worry, chemoprevention knowledge, self-efficacy) and decision quality (decision conflict, chemoprevention informed choice) based upon patient surveys administered at baseline, 1 and 6 months after randomization. Among 282 evaluable high-risk women enrolled from November 2016 to March 2020, mean age was 57 years (SD, 9.9) and mean 5-year invasive breast cancer risk was 2.98% (SD, 1.42). There was no significant difference in chemoprevention uptake at 6 months between the intervention and control groups (2.1% vs. 3.5%). Comparing the intervention and control arms at 1 month, there were significant differences among high-risk women in accurate breast cancer risk perceptions (56% vs. 39%, P = 0.017), adequate chemoprevention knowledge (49% vs. 27%, P < 0.001), mean decision conflict (34.0 vs. 47.0, P < 0.001), and informed choice (41% vs. 23%, P = 0.003). These differences were no longer significant at 6 months. Although our decision support tools did not result in a significant increase in chemoprevention uptake, we did observe improvements in decision antecedents and decision quality measures.

PREVENTION RELEVANCE

In this randomized controlled trial of decision support for 300 high-risk women and 50 healthcare providers, we did not observe a significant increase in chemoprevention uptake, which remained low at under 5%. However, these decision support tools may increase knowledge and informed choice about breast cancer chemoprevention.

Impacts of sex steroids and aromatase inhibitor on performances, carcass characteristics and gonadal histology of broiler chickens slaughtered at different ages

This experiment was established to evaluate the influence of synthetic steroid hormone and aromatase inhibitor on performance, carcass characteristics, hormonal profile and gonadal structure of broiler chickens slaughtered at two different ages. A total of 360 Cobb Avian48 chicks were sexed and distributed randomly into three groups: Tam10 group; birds received Tamoxifen10mg (Tamfen 10 mg^@ ) orally at a level of 10 mg/kg body weight daily from the 3rd till the 9th day of age; BOL group: birds injected intramuscularly with Boldenone undecylenate (BOLD-GAN^@ 0.1 mg/kg) at the 5th and the 9th day of age; and Control group. BOL injection or Tam supplementation improved performance traits compared with the control group. Although Tam positive effect appeared early before the 5th week of age, the BOL effect was delayed to the 6th week. BOL injection improved carcass characteristics of both sexes at both 5 and 6 weeks slaughtering ages. Regardless of treatment effect, the mortality% was higher in the late weeks of age than in the early weeks. Moreover, BOL treatment increased comb% compared with control and Tam treatments. Generally, males had significantly higher testosterone levels and lower oestrogen levels than females. Males treated with Boldenone had the highest testosterone level, although testosterone levels did not differ considerably among females of the various groups. BOL treatment females had the lowest oestrogen level. Both Tam10 and Boldenone had adverse effects on testicular and ovarian histology, affecting the typical structures. Finally, we concluded that the anabolic effect of Tam10 may be achieved in griller broilers production without changing the sex hormones assay. Although Boldenone achieved an anabolic effect without changing blood sex hormone levels, this effect is induced early with females and delayed with males, which prolongs the marketing period. The goal is to shorten this period. Therefore, this material can only be used with the possibility of separating females from males to be used with females only.

Tamoxifen in mastalgia: A meta-analysis

OBJECTIVES

Tamoxifen is prescribed for chronic mastalgia at a dosage of one 10- or 20-mg tablet for 3-6 months. A topical preparation of this drug has recently been approved. The aim of this study was to meta-analyze the effectiveness of tamoxifen and its different regimens for the treatment of mastalgia. We also sought to summarize the side effects and the follow-up results of these treatments.

DATA SOURCES

We searched the databases of PubMed/ MEDLINE, Central, Embase, and EBSCO from August 2021 to September 2021.

STUDY SELECTION

Articles on the effects of tamoxifen in mastalgia were searched, and randomized controlled trials were retrieved for inclusion in this study. PRISMA guidelines were followed, and we selected 9 articles for the meta-analysis.

DATA EXTRACTION AND SYNTHESIS

A proforma was prepared for data collection. RevMan 5.4 software was used for methodological quality assessment, statistical analysis, and preparation of forest plots. Oral tamoxifen performed better than placebo (RR 2.04; 95% CI 1.49-2.78, P < 0.001). No significant difference in efficacy was seen between the 10- and 20-mg dosages (RR 1.08; 95% CI 0.97-1.21, P = 0.18) when used for 3 months.

CONCLUSION

Oral tamoxifen is helpful in long-standing mastalgia. It is safe and effective at an oral dose of 10 mg.

Tamoxifen Increased Parasite Burden and Induced a Series of Histopathological and Immunohistochemical Changes During Chronic Toxoplasmosis in Experimentally Infected Mice

The global distribution of breast cancer and the opportunistic nature of the parasite have resulted in many patients with breast cancer becoming infected with toxoplasmosis. However, very limited information is available about the potential effects of tamoxifen on chronic toxoplasmosis and its contribution to the reactivation of the latent infection. The present study investigated the potential effects of tamoxifen on chronic toxoplasmosis in animal models (Swiss albino mice). Following induction of chronic toxoplasmosis and treatment with the drug for 14 and 28 days, the anti-parasitic effects of tamoxifen were evaluated by parasitological assessment and counting of Toxoplasma cysts. In addition, the effects of the drug on the parasite load were evaluated and quantitated using TaqMan real-time quantitative PCR followed by investigation of the major histopathological changes and immunohistochemical findings. Interestingly, tamoxifen increased the parasite burden on animals treated with the drug during 14 and 28 days as compared with the control group. The quantification of the DNA concentrations of Toxoplasma P29 gene after the treatment with the drug revealed a higher parasite load in both treated groups vs. control groups. Furthermore, treatment with tamoxifen induced a series of histopathological and immunohistochemical changes in the kidney, liver, brain, and uterus, revealing the exacerbating effect of tamoxifen against chronic toxoplasmosis. These changes were represented by the presence of multiple T. gondii tissue cysts in the lumen of proximal convoluted tubules associated with complete necrosis in their lining epithelium of the kidney section. Meanwhile, liver tissue revealed multiple T. gondii tissue cysts in hepatic parenchyma which altered the structure of hepatocytes. Moreover, clusters of intracellular tachyzoites were observed in the lining epithelium of endometrium associated with severe endometrial necrosis and appeared as diffuse nuclear pyknosis combined with sever mononuclear cellular infiltration. Brain tissues experienced the presence of hemorrhages in pia mater and multiple T. gondii tissue cysts in brain tissue. The severity of the lesions was maximized by increasing the duration of treatment. Collectively, the study concluded novel findings in relation to the potential role of tamoxifen during chronic toxoplasmosis. These findings are very important for combating the disease, particularly in immunocompromised patients which could be life-threatening.

Formulation Development for Transdermal Delivery of Raloxifene, a Chemoprophylactic Agent against Breast Cancer

Raloxifene (RLX) is a second-generation selective estrogen receptor modulator approved for the prevention of invasive breast cancer in women. Oral therapy of RLX requires daily intake and is associated with side effects that may lead to low adherence. We developed a weekly transdermal delivery system (TDS) for the sustained delivery of RLX to enhance the therapeutic effectiveness, increase adherence, and reduce side effects. We evaluated the weekly transdermal administration of RLX using passive permeation, chemical enhancers, physical enhancement techniques, and matrix- and reservoir-type systems, including polymeric gels. In vitro permeation studies were conducted using vertical Franz diffusion cells across dermatomed human skin or human epidermis. Oleic acid was selected as a chemical enhancer based on yielding the highest drug delivery amongst the various enhancers screened and was incorporated in the formulation of TDSs and polymeric gels. Based on in vitro results, both Eudragit- and colloidal silicon dioxide-based transdermal gels of RLX exceeded the target flux of 24 μg/cm²/day for 7 days. An infinite dose of these gels delivered 326.23 ± 107.58 µg/ cm² and 498.81 ± 14.26 µg/ cm² of RLX in 7 days, respectively, successfully exceeding the required target flux. These in vitro results confirm the potential of reservoir-based polymeric gels as a TDS for the weekly administration of RLX.

Tamoxifen Derivatives Alter Retromer-Dependent Endosomal Tubulation and Sorting to Block Retrograde Trafficking of Shiga Toxins

Shiga toxin 1 and 2 (STx1 and STx2) undergo retrograde trafficking to reach the cytosol of cells where they target ribosomes. As retrograde trafficking is essential for disease, inhibiting STx1/STx2 trafficking is therapeutically promising. Recently, we discovered that the chemotherapeutic drug tamoxifen potently inhibits the trafficking of STx1/STx2 at the critical early endosome-to-Golgi step. We further reported that the activity of tamoxifen against STx1/STx2 is independent of its selective estrogen receptor modulator (SERM) property and instead depends on its weakly basic chemical nature, which allows tamoxifen to increase endolysosomal pH and alter the recruitment of retromer to endosomes. The goal of the current work was to obtain a better understanding of the mechanism of action of tamoxifen against the more disease-relevant toxin STx2, and to differentiate between the roles of changes in endolysosomal pH and retromer function. Structure activity relationship (SAR) analyses revealed that a weakly basic amine group was essential for anti-STx2 activity. However, ability to deacidify endolysosomes was not obligatorily necessary because a tamoxifen derivative that did not increase endolysosomal pH exerted reduced, but measurable, activity. Additional assays demonstrated that protective derivatives inhibited the formation of retromer-dependent, Golgi-directed, endosomal tubules, which mediate endosome-to-Golgi transport, and the sorting of STx2 into these tubules. These results identify retromer-mediated endosomal tubulation and sorting to be fundamental processes impacted by tamoxifen; provide an explanation for the inhibitory effect of tamoxifen on STx2; and have important implications for the therapeutic use of tamoxifen, including its development for treating Shiga toxicosis.

Primary Eccrine Adenocarcinoma: A Rare but Dangerous Lesion of the Eyelid

Sweat gland carcinomas can be of eccrine or apocrine origin, with the former being more common in the eyelid. They can also be of three different types, the most common of which is mucin-producing sweat gland carcinoma, which is most often a low-grade malignancy. Here, we report a case of a primary estrogen receptor-positive eccrine adenocarcinoma of the eyelid that clinically presented like a cyst of Moll. Importantly, in our experience with this lesion, this rare malignancy was repeatedly misdiagnosed as less sinister lesions, surgical resection margins of the lesion could be easily underestimated, and close liaison with our general surgical colleagues was vital to exclude more common breast carcinoma. This case highlights the dangers of referral recommendation policies (e.g., procedures of limited clinical value as used by primary care) and the importance of incisional biopsy in the management of periocular lesions.

Dutch women's intended participation in a risk-based breast cancer screening and prevention programme: a survey study identifying preferences, facilitators and barriers

BACKGROUND

Risk-based breast cancer screening may improve the benefit-harm ratio of screening by tailoring policy to a woman's personal breast cancer risk. This study aims to explore Dutch women's preferences regarding the organisation and implementation of a risk-based breast cancer screening and prevention programme, identifying potential barriers and facilitators to uptake.

METHODS

A total of 5110 participants in the Dutch Personalised RISk-based MAmmography screening (PRISMA) study were invited, of whom 942 completed a two-part web-based survey. The first part contained questions about personal characteristics; for the second part, women were randomly assigned to one of four hypothetical breast cancer risk scenarios (i.e. low, average, moderate, or high) with subsequent tailored screening and prevention advice. Descriptive statistics are used to present women's organisational preferences. Univariable and multivariable logistic regression analyses were performed using seven proxy measures for acceptability of risk-based screening (e.g., interest in risk) and risk-based prevention (e.g., willingness to change diet).

RESULTS

Interest in breast cancer risk was high (80.3%). Higher assigned risk scenario was most consistently associated with acceptance of tailored screening and prevention recommendations. Increased acceptance of lifestyle changes was additionally associated with higher education. Having a first degree family history of breast cancer decreased women's motivation to participate in preventative lifestyle measures. Acceptability of medication was associated with a woman's general beliefs about the (over)use and benefit-harm balance of medication.

CONCLUSIONS

Dutch women generally appear in favour of receiving their breast cancer risk estimate with subsequent tailored screening and prevention recommendations. However, women's level of acceptance depends on their assigned risk category. Offering tailored screening and prevention recommendations to low-risk women will be most challenging. Educating women on the benefits and harms of all risk-based screening and prevention strategies is key to acceptability and informed decision-making.

Ratite oils for local transdermal therapy of 4-OH tamoxifen: development, characterization, and ex vivo evaluation

The anti-inflammatory property of ratite oils as well as its ability to act as a penetration enhancer makes it an ideal agent to be used in transdermal formulations. The present study aims to develop an effective transfersomal delivery of 4-hydroxytamoxifen (4-OHT), an anti-cancer drug, using ratite oil as a carrier agent for the treatment of breast cancer (BC). The 4-OHT transfersomes were prepared with and without ratite oils using soy phosphatidylcholine and three different edge activators (EAs) in five different molar ratios using the rotary evaporation-ultrasonication method. Optimal transfersome formulations were selected using physical-chemical characterization and ex vivo studies. Results from physical-chemical characterization of the developed formulations found sodium taurocholate to be the most suitable EA, which recorded highest entrapment efficiency of 95.1 ± 2.70% with 85:15, (w/w) and lowest vesicle size of 82.3 ± 0.02 nm with 75:25, (w/w) molar ratios. TEM and DSC studies showed that the vesicles were readily identified and present in a nearly perfect spherical shape. In addition, formulations with emu oil had better stability than formulations with ostrich oil. Physical stability studies at 4 °C showed that ratite oil transfersomes were stable up to 4 weeks, while transfersomes without ratite oils were stable for 8 weeks. Ex vivo permeability studies using porcine skin concluded that 4-OHT transfersomal formulations with (85:15, w/w) without emu oil have the potential to be used in transdermal delivery approach to enhance permeation of 4-OHT, which may be beneficial in the treatment of BC.

Exploring the Promising Potential of High Permeation Vesicle-Mediated Localized Transdermal Delivery of Docetaxel in Breast Cancer To Overcome the Limitations of Systemic Chemotherapy

The currently available systemic chemotherapy for treating breast cancer often results in serious systemic side effects and compromises patient compliance. The distinct anatomical features of human breasts (e.g., embryological origin of breast skin, highly developed internal lymphatic and venous circulation, and the presence of mammary fat layers) help in preferential accumulation of drugs into breasts after topical application on breast region. This unique feature is termed as localized transdermal delivery which could be utilized for effectively delivering anticancer agents to treat breast cancer and reducing the systemic side effects by limiting their presence in blood. However, the clinical effectiveness of this drug delivery approach is highly limited by barrier properties of skin reducing the permeation of anticancer drugs. In the present work, we have developed high permeation vesicles (HPVs) using phospholipids and synergistic combination of permeation enhancers (SCOPE) to improve the skin permeation of drugs. Docetaxel (DTX) was used as a model drug for hypothesis testing. The optimized SCOPE mixture composed of sodium oleate/sodium lauryl ether sulfate/propylene glycol in 64:16:20% w/w ratio. DTX HPVs were prepared using phospholipid: SCOPE, 8:2% w/w ratio. DTX HPVs exhibited as a uniform deformable vesicles with size range 124.2 ± 7.6 nm, significantly improved skin permeation profile, and sustained drug release until 48 h. Superior vesicle deformability, better vesicle membrane fluidization, and SCOPE mediated enhancement in skin fluidization were the prime factors behind enhancement of DTX permeation. The improved cellular uptake, reduced IC₅₀ values, and higher apoptotic index of DTX HPVs in MCF-7 and MDA-MB-231 cells ensured the therapeutic effectiveness of HPV based therapy. Also, HPVs were found to be predominantly internalized inside cells through clathrin and caveolae-dependent endocytic pathways. Bioimaging analysis in mice confirmed the tumor penetration potential and effective accumulation of HPVs inside tumors after topical application. In vivo studies were carried out in comparison with marketed intravenous DTX injection (Taxotere) to compare the effectiveness of topical chemotherapy. The topical application of DTX HPV gel in tumor bearing mice resulted in nearly 4-fold tumor volume reduction which was equivalent to intravenous Taxotere therapy. Toxicity analysis of DTX HPV gel in comparison with intravenous Taxotere dosing showcased remarkably lower levels of toxicity biomarkers (aspartate transaminase (AST), alanine transaminase (ALT), blood urea nitrogen (BUN), and creatinine), indicating improved safety of topical chemotherapy. Overall results warranted the effectiveness of topical DTX chemotherapy to reduce tumor burden with substantially reduced risk of systemic toxicities in breast cancer.

Anthonotha macrophylla P. Beauv (Caesalpiniaceae) aqueous extract exhibits antiestrogenic effects in vitro and in vivo

Background Phytoestrogens are natural compounds known as natural selective estrogen receptor modulators used as alternatives against estrogen-dependent cancers. This study aims to evaluate the antiestrogenic effects of Anthonotha macrophylla, a plant used to treat cancer in Cameroon. Methods The estrogenic/antiestrogenic activities of A. macrophylla aqueous extract were evaluated in vitro using MCF-7 cell proliferation assay. Moreover, a classical uterotrophic test was carried out to evaluate the antiestrogenic effects of A. macrophylla in rats. Changes in the uterus, vagina, and mammary glands were used as endpoints of estrogenicity. Results Anthonotha macrophylla induced antiestrogenic effects in vitro at all the tested concentrations by inhibiting estradiol-induced MCF-7 cell proliferation (p < 0.001). In vivo, a coadministration of estradiol with A. macrophylla extract led to the decrease of uterine [150 (p < 0.05) and 300 (p < 0.01) mg/kg body weight (BW)] and vaginal [75 (p < 0.01) and 300 (p < 0.05) mg/kg BW] epithelial thickness. In addition, a reduction in the mammary gland acini lumen's diameter was also observed at 75 and 150 mg/kg. Gas chromatography-time-of-flight-mass spectrometry analysis showed that phenolic acid derivatives are present in A. macrophylla extract, which are well known to be endowed with estrogenic/antiestrogenic properties. The LD50 of A. macrophylla was estimated to be less than 2000 mg/kg. Conclusions Anthonotha macrophylla aqueous extract has antiestrogenic properties. This could promote more studies to explore its ability to prevent estrogen-dependent cancers.

Effect of tamoxifen on the Notch signaling pathway in ovarian follicles of mice

We investigated the effect of tamoxifen (TAM) treatment on the Notch signaling pathway in mouse ovary. Mice were randomly divided into four groups. Control group A animals were untreated. Control group B animals were treated with the vehicle only. Animals of the 0.5 TAM group received 0.5 mg/day TAM. Animals of the 1.5 TAM group received 1.5 mg/day of TAM. TAM was injected subcutaneously for 5 days. Body weights were measured at the start and end of the experiment. Sections were stained using Crossman's modified trichrome to examine general ovarian structure. Other sections were immunostained to demonstrate Jagged 1, Ki 67 and Notch 2. The TUNEL method was used to detect apoptosis. No significant differences in body weight or ovarian weight were found among the experimental groups. The number of primordial follicles was greater in the treatment groups than in the control groups, while the number of antral follicles and corpora lutea were reduced in the treatment groups. Cell proliferation rates were decreased by TAM treatment and cystic follicles were formed in the ovarian stroma. Notch 2 expression in the granulosa cells was increased following TAM administration, but no change was found in Jagged 1 expression. TAM administration suppressed follicular development and exhibited a negative effect on ovarian morphology. Our findings suggest that the Notch pathway participates in the action of TAM. We suggest that it may be useful to use Notch pathway regulators to adjust the effects of TAM on the ovary.

Enhanced anti-mammary gland cancer activities of tamoxifen-loaded erythropoietin-coated drug delivery system

Nanomedicine is an emerging area in the medical field, particularly in the treatment of cancers. Nanostructured lipid carrier (NLC) was shown to be a good nanoparticulated carrier for the delivery of tamoxifen (TAM). In this study, the tamoxifen-loaded erythropoietin-coated nanostructured lipid carriers (EPO-TAMNLC) were developed to enhance the anti-cancer properties and targetability of TAM, using EPO as the homing ligand for EPO receptors (EpoRs) on breast cancer tissue cells. Tamoxifen-loaded NLC (TAMNLC) was used for comparison. The LA7 cells and LA7 cell-induced rat mammary gland tumor were used as models in the study. Immunocytochemistry staining showed that LA7 cells express estrogen receptors (ERs) and EpoRs. EPO-TAMNLC and TAMNLC significantly (p<0.05) inhibited proliferation of LA7 in dose- and time-dependent manner. EPO-TAMNLC induced apoptosis and G₀/G₁ cell cycle arrest of LA7 cells. Both drug delivery systems showed anti-mammary gland tumor properties. At an intravenous dose of 5 mg kg^-1 body weight, EPO-TAMNLC and TAMNLC were not toxic to rats, suggesting that both are safe therapeutic compounds. In conclusion, EPO-TAMNLC is not only a unique drug delivery system because of the dual drug-loading feature, but also potentially highly specific in the targeting of breast cancer tissues positive for ERs and EpoRs. The incorporation of TAM into NLC with and without EPO coat had significantly (p<0.05) improved specificity and safety of the drug carriers in the treatment of mammary gland tumors.

Tamoxifen in horses: pharmacokinetics and safety study

Background

Tamoxifen (TAM), a selective modulator of estrogen receptors (SERMs) has been recently explored as a therapeutic option for the oral treatment of airway inflammation in the horse. The objective of this work was to establish pharmacokinetic parameters of TAM and its main metabolites in equines, as well as to determine its clinical safety in short-term treatments.

Results

We determined TAM and its three main metabolites (4-OH tamoxifen, endoxifen, and N-desmethyl tamoxifen) in plasma after single administration of 0.25 mg/kg in healthy adult horses (n = 12). A maximum concentration of TAM was achieved 3 h after the oral administration (4.65 pg/mL ± 1.69); 4-OH tamoxifen was the metabolite that reached the highest concentration (78 pg/mL ± 70), followed by N-desmethyl tamoxifen (0.43 pg / mL ± 0.48), and finally endoxifen (0.17 pg/mL ± 0.17). All metabolites showed peak concentration 2 h after oral administration of the drug. Oral TAM bioavailability was 13,15% ± 4,18, with a steady state volume of distribution of 7831 ± 2922 (L/kg). Elimination half-life was 15.40 ± 5.80 h, and clearance was 5876 ± 699 (mL/kg/min). Clinical safety of TAM was determined over a 7-day course of treatment (0.25 mg/kg, orally q 24 h, n = 20). No adverse effects were observed through clinical examination, blood hematology, serum biochemistry, ophthalmological and reproductive examinations. Endometrial edema observed in some mares was attributed to normal cyclic activity.

Conclusions

Tamoxifen has moderate oral bioavailability and a large volume of distribution, with three main metabolites in horses. Additionally, oral TAM administration over a 7-day treatment period demonstrated to be clinically safe, without adverse effects on clinical, hematological or serum biochemical parameters. These data could contribute to the continued research into this drug’s potential for the treatment of different inflammatory conditions in equine species.

Electronic supplementary material

The online version of this article (10.1186/s13620-019-0143-7) contains supplementary material, which is available to authorized users.

Tamoxifen blocks retrograde trafficking of Shiga toxin 1 and 2 and protects against lethal toxicosis

This study reports an unexpected role of late endosome–lysosome fusion in early endosome-to-Golgi trafficking of Shiga toxins and identifies tamoxifen to be a potent inhibitor of Shiga toxicosis.

Shiga toxin 1 (STx1) and 2 (STx2), produced by Shiga toxin–producing Escherichia coli, cause lethal untreatable disease. The toxins invade cells via retrograde trafficking. Direct early endosome-to-Golgi transport allows the toxins to evade degradative late endosomes. Blocking toxin trafficking, particularly at the early endosome-to-Golgi step, is appealing, but transport mechanisms of the more disease-relevant STx2 are unclear. Using data from a genome-wide siRNA screen, we discovered that disruption of the fusion of late endosomes, but not autophagosomes, with lysosomes blocked the early endosome-to-Golgi transport of STx2. A subsequent screen of clinically approved lysosome-targeting drugs identified tamoxifen (TAM) to be a potent inhibitor of the trafficking and toxicity of STx1 and STx2 in cells. The protective effect was independent of estrogen receptors but dependent on the weak base property of TAM, which allowed TAM to increase endolysosomal pH and alter endosomal dynamics. Importantly, TAM treatment enhanced survival of mice injected with a lethal dose of STx1 or STx2. Thus, it may be possible to repurpose TAM for treating Shiga toxin–producing E. coli infections.

CCAAT-displacement protein/cut homeobox transcription factor (CUX1) represses estrogen receptor-alpha (ER-α) in triple-negative breast cancer cells and can be antagonized by muscadine grape skin extract (MSKE)

Triple-Negative Breast Cancers (TNBCs) are the most difficult to treat subtype of breast cancer and are often associated with high nuclear expression of Snail and Cathepsin L (Cat L) protease. We have previously shown that Snail can increase Cat L expression/activity in prostate and breast cancer cells. This study investigated the role of CUX1 (a downstream substrate of Cat L) in TNBC. We showed that Cat L and CUX1 were highly expressed in TNBC patient tissue/cell lines, as compared to ER-positive samples, using cBioportal data and western blot/zymography analyses. Additionally, luciferase reporter and chromatin immunoprecipitation assays showed that CUX1 directly bound to estrogen receptor-alpha (ER-α) promoter in MDA-MB-468, a representative TNBC cell line, and that CUX1 siRNA could restore ER-α transcription and protein expression. Furthermore, Snail and CUX1 expression in various TNBC cell lines was inhibited by muscadine grape skin extract (MSKE, a natural grape product rich in anthocyanins) or Cat L inhibitor (Z-FY-CHO) leading to decreased cell invasion and migration. MSKE decreased cell viability and increased expression of apoptotic markers in MDA-MB-468 cells, with no effect on non-tumorigenic MCF10A cells. MSKE also decreased CUX1 binding to ER-α promoter and restored ER-α expression in TNBC cells, while both MSKE and CUX1 siRNA restored sensitivity to estradiol and 4-hydoxytamoxifen as shown by increased cell viability. Therefore, CUX1 activated by Snail-Cat L signaling may contribute to TNBC via ER-α repression, and may be a viable target for TNBC using natural products such as MSKE that targets cancer and not normal cells.

GPR119 agonist enhances gefitinib responsiveness through lactate-mediated inhibition of autophagy

Background

Ligand-dependent activation of the G-protein coupled receptor 119 (GPR119) lowers blood glucose via glucose-dependent insulin secretion and intestinal glucagon-like peptide-1 production. However, the function of GPR119 in cancer cells has not been studied.

Methods

GPR119 expression was assessed by real-time qPCR and immunohistochemistry in human breast cancer cell lines and breast cancer tissues. Cell proliferation and cell cycle analyses were performed by Incucyte® live cell analysis system and flow cutometry, respectively. Autophagy activity was estimeated by western blottings and LC3-GFP transfection.

Results

mRNA or protein expression of GPR119 was detected in 9 cancer cell lines and 19 tissue samples. Cotreatment with GPR119 agonist (MBX-2982 or GSK1292263) significantly potentiated gefitinib-induced cell growth inhibition in gefitinib-insensitive MCF-7 and MDA-MB-231 breast cancer cells. We observed that caspase-3/7 activity was enhanced with the downregulation of Bcl-2 in MCF-7 cells exposed to MBX-2982. Gefitinib-induced autophagy is related with cancer cell survival and chemoresistance. GPR119 agonists inhibit gefitinib-induced autophagosome formation in MCF-7 and MDA-MB-231 cells. MBX-2982 also caused a metabolic shift to enhanced glycolysis accompanied by reduced mitochondrial oxidative phosphorylation. MBX-2982 increased intracellular (~ 2.5 mM) and extracellular lactate (~ 20 mM) content. Gefitinib-mediated autophagy was suppressed by 20 mM lactate in MCF-7 cells.

Conclusions

GPR119 agonists reduced mitochondrial OXPHOS and stimulated glycolysis in breast cancer cells, with consequent overproduction of lactate that inhibited autophagosome formation. Because autophagy is crucial for the survival of cancer cells exposed to TKIs, GPR119 agonists potentiated the anticancer effects of TKIs.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0949-2) contains supplementary material, which is available to authorized users.

Cancer Prevention: Lessons Learned and Future Directions

In this review, we address selected areas that are central to the state-of-the-art of cancer prevention science. The emphasis on prevention as a viable and critical approach to decreasing cancer mortality has gained traction in recent years, evidenced by its inclusion in the US Vice President's Cancer Initiative (also termed 'Moonshot'). Cancer prevention occurs by arresting, slowing down, or reversing the carcinogenic process before invasion into surrounding tissue or by avoiding or blocking causative exposure. An important challenge is to identify individuals who will benefit most from preventive interventions with the least possible harm. Preventive interventions range from avoiding known carcinogens (e.g., tobacco or asbestos) to intervening with anticarcinogenic strategies (behavioral modifications , such as diet and exercise; medications; nutritional agents; and vaccination against causative agents). Here, we focus on active intervention with measures involving pharmaceutical and immunological agents.

PAMAM dendrimers in drug delivery: loading efficacy and polymer morphology

The binding efficacy of anticancer drugs doxorubicin and tamoxifen with polyamidoamine (PAMAM-G4) dendrimers was studied in aqueous solution at physiological pH. The results of multiple spectroscopic methods, transmission electron microscopy (TEM), and molecular modeling of conjugated drug–polymer were examined. Structural analysis showed that drug–polymer conjugation occurs mainly via H-bonding and hydrophilic and hydrophobic contacts. Doxorubicin forms a more stable conjugate with PAMAM-G4 than tamoxifen. The drug loading efficacy was 40%–50%. The TEM images showed major changes in the PAMAM morphology upon drug encapsulation. Modeling showed that drug is located in the polymer surface and in the internal cavities. PAMAM nanoparticles are capable of transporting doxorubicin and tamoxifen in vitro. This minireview presents the most recent work performed with the dendrimers demonstrating their usefulness for drug delivery in cancer therapy.

Mammographic density and ageing: A collaborative pooled analysis of cross-sectional data from 22 countries worldwide

BACKGROUND

Mammographic density (MD) is one of the strongest breast cancer risk factors. Its age-related characteristics have been studied in women in western countries, but whether these associations apply to women worldwide is not known.

METHODS AND FINDINGS

We examined cross-sectional differences in MD by age and menopausal status in over 11,000 breast-cancer-free women aged 35-85 years, from 40 ethnicity- and location-specific population groups across 22 countries in the International Consortium on Mammographic Density (ICMD). MD was read centrally using a quantitative method (Cumulus) and its square-root metrics were analysed using meta-analysis of group-level estimates and linear regression models of pooled data, adjusted for body mass index, reproductive factors, mammogram view, image type, and reader. In all, 4,534 women were premenopausal, and 6,481 postmenopausal, at the time of mammography. A large age-adjusted difference in percent MD (PD) between post- and premenopausal women was apparent (-0.46 cm [95% CI: -0.53, -0.39]) and appeared greater in women with lower breast cancer risk profiles; variation across population groups due to heterogeneity (I2) was 16.5%. Among premenopausal women, the √PD difference per 10-year increase in age was -0.24 cm (95% CI: -0.34, -0.14; I2 = 30%), reflecting a compositional change (lower dense area and higher non-dense area, with no difference in breast area). In postmenopausal women, the corresponding difference in √PD (-0.38 cm [95% CI: -0.44, -0.33]; I2 = 30%) was additionally driven by increasing breast area. The study is limited by different mammography systems and its cross-sectional rather than longitudinal nature.

CONCLUSIONS

Declines in MD with increasing age are present premenopausally, continue postmenopausally, and are most pronounced over the menopausal transition. These effects were highly consistent across diverse groups of women worldwide, suggesting that they result from an intrinsic biological, likely hormonal, mechanism common to women. If cumulative breast density is a key determinant of breast cancer risk, younger ages may be the more critical periods for lifestyle modifications aimed at breast density and breast cancer risk reduction.

Preventive and Risk Reduction Strategies for Women at High Risk of Developing Breast Cancer: a Review

Breast cancer is the most commonly diagnosed invasive cancer among women. Many factors, both genetic and non-genetic, determine a woman's risk of developing breast cancer and several breast cancer risk prediction models have been proposed. It is vitally important to risk stratify patients as there are now effective preventive strategies available. All women need to be counseled regarding healthy lifestyle recommendations to decrease breast cancer risk. As such, management of these women requires healthcare professionals to be familiar with additional risk factors so that timely recommendations can be made on surveillance/risk-reducing strategies. Breast cancer risk reduction strategies can be better understood by encouraging the women at risk to participate in clinical trials to test new strategies for decreasing the risk. This article reviews the advances in the identification of women at high risk of developing breast cancer and also reviews the strategies available for breast cancer prevention.

Translation of a Tissue-Selective Rexinoid, UAB30, to the Clinic for Breast Cancer Prevention

This review focuses on our efforts to translate a low-toxicity retinoid X receptor-selective agonist, UAB30, to the clinic for the prevention of breast cancers. The review is divided into several sections. First, the current status of breast cancer prevention is discussed. Next, preclinical studies are presented that support translation of rexinoids to the clinic for cancer prevention. While current FDAapproved retinoids and rexinoids demonstrate profound effects in treating cancers, they lack sufficient safety for long term use in the high risk population that is otherwise disease free. The review stresses the need to identify cancer preventive drugs that are effective and safe in order to gain wide use in the clinic. Due to the heterogeneity of the disease, UAB30 is evaluated for the prevention of ER-positive and ER-negative mammary cancers. Since selective estrogen receptor modulators and aromatase inhibitors are used clinically to prevent and treat ER-positive breast cancers, preclinical studies also must demonstrate efficacy of UAB30 in combination with existing drugs under use in the clinic. To support an Investigational New Drug Application to the FDA, data on pharmacology and toxicity as well as mutagenicity is gathered prior to human trials. The review concludes with a discussion of the outcomes of human Phase 0/1 clinical trials that determine the safety and pharmacology of UAB30. These studies are essential before this agent is evaluated for efficacy in phase 2 trials. Success in phase 2 evaluation is critical before long-term and costly phase 3 trials are undertaken. The lack of surrogate biomarkers as endpoints for phase 2 evaluation of rexinoid preventive agents is discussed.

A Way Forward for Cancer Chemoprevention: Think Local

As cells progress through carcinogenesis, the associated exponential expansion of genetic and molecular aberrations and resultant heterogeneity make therapeutic success increasingly unattainable. Therapeutic intervention at early stages of carcinogenesis that occurs within the primary organ and in the face of a lower burden of molecular aberrations, constitutes a basic tenet of cancer chemoprevention, and provides a situation that favors a greater degree of therapeutic efficacy compared with that of advanced cancer. A longstanding barrier to chemoprevention relates to the requirement for essentially no systemic toxicity, and the fact that when large numbers of people are treated, the emergence of systemic toxicity is almost universal. A rational means to address this in fact relates to a second basic tenet of the chemopreventive strategy: the focus of therapeutic intervention is to disrupt a process that is in essence localized to a single organ. Based upon this consideration, a strategy which is based upon local delivery of therapeutics to an at-risk organ will achieve therapeutic efficacy while avoiding systemic delivery and its associated toxicity. This article will review the rationale for undertaking such an approach, describe successful clinical achievements based on this strategy, describe ongoing efforts to expand the impact of this approach, and together will highlight the high impact that this approach has already had on the field as well as its extremely high potential for future impact. Cancer Prev Res; 10(1); 14-35. ©2016 AACR.

Crateva adansonii DC, an African ethnomedicinal plant, exerts cytotoxicity in vitro and prevents experimental mammary tumorigenesis in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Crateva adansonii DC is a plant traditionally used in Cameroon to treat constipation, asthma, snakebites, postmenopausal complaints and cancers.

AIM

The anticancer potential of the dichloromethane/methanol extract of C. adansonii stem barks was investigated using human breast cancer cell and 7,12 dimethylbenz(a)anththracene (DMBA)-induced mammary tumorigenesis model in rats.

MATERIAL AND METHODS

The cytotoxicity of C. adansonii extract was assessed in vitro towards breast carcinoma (MCF-7 and MDA-MB-231) and non-tumoral cell lines (NIH/3T3 and HUVEC) by Alamar Blue assay. Furthermore, in vivo studies were performed on female Wistar rats treated either with C. adansonii extract at a dose of 75 or 300mg/kg body weight or with tamoxifen (3.3mg/kg body weight), starting 1 week prior DMBA treatment and lasted 12 weeks. The investigation focused on tumour burden, tumour DNA fingerprint, morphological, histological, hematological, and biochemical parameters.

RESULTS

CC50 values for the in vitro assays were 289µg/mL against MCF-7 cells and >500µg/mL in others cells, leading to a selectivity index ≥1.73. C. adansonii extract significantly (p<0.001) revealed in vivo the reduction of the cumulative tumour yield (87.23%), total tumour burden (88.64%), average tumour weight (71.11%) and tumour volume (78.07%) at the dose of 75mg/kg as compared to DMBA control group. A weak effect was also observed at 300mg/kg. This extract showed a moderate hyperplasia at the dose of 75mg/kg while at 300mg/kg no significant change was noted as compared to DMBA group. It protected rats from the DNA alteration induced by DMBA and increased antioxydant enzymes activities in mammary gland tissue homogenates. In addition, Ultra-High Performance Liquid Chromatography/ESI-QTOF-Mass Spectrometry analysis of C. adansonii extract detected structure-related of many well-known anticancer agents such as flavane gallate, flavonol, phenylpropanoïds, sesquiterpene derivatives, gallotannins and lignans. The LD50 of C. adansonii was estimated to be greater than 5000mg/kg.

CONCLUSIONS

These aforementioned results suggest that the C. adansonii extract may possess antitumor constituents, which could combat breast cancer and prevent chemically-induced breast cancer in rats.

Effect of low doses of estradiol and tamoxifen on breast cancer cell karyotypes

Evidence supports a role of 17&-estradiol (E2) in carcinogenesis and the large majority of breast carcinomas are dependent on estrogen. The anti-estrogen tamoxifen (TAM) is widely used for both treatment and prevention of breast cancer; however, it is also carcinogenic in human uterus and rat liver, highlighting the profound complexity of its actions. The nature of E2- or TAM-induced chromosomal damage has been explored using relatively high concentrations of these agents, and only some numerical aberrations and chromosomal breaks have been analyzed. This study aimed to determine the effects of low doses of E2 and TAM (10(&8 )mol L(&1) and 10(&6 )mol L(&1) respectively) on karyotypes of MCF7, T47D, BT474, and SKBR3 breast cancer cells by comparing the results of conventional karyotyping and multi-FISH painting with cell proliferation. Estrogen receptor (ER)-positive (+) cells showed an increase in cell proliferation after E2 treatment (MCF7, T47D, and BT474) and a decrease after TAM treatment (MCF7 and T47D), whereas in ER& cells (SKBR3), no alterations in cell proliferation were observed, except for a small increase at 96 h. Karyotypes of both ER+ and ER& breast cancer cells increased in complexity after treatments with E2 and TAM leading to specific chromosomal abnormalities, some of which were consistent throughout the treatment duration. This genotoxic effect was higher in HER2+ cells. The ER&/HER2+ SKBR3 cells were found to be sensitive to TAM, exhibiting an increase in chromosomal aberrations. These in vitro results provide insights into the potential role of low doses of E2 and TAM in inducing chromosomal rearrangements in breast cancer cells.

Molecular mechanisms and mode of tamoxifen resistance in breast cancer

Breast cancer is one of the most common cancers in women around the globe Tamoxifen is used for the last 40 years as an endocrine therapy for breast cancer. This resulted in the reduction of mortality rate by 30% and it still remains one of the most effective therapies against breast cancer. However, resistance against tamoxifen is still one of the major hurdles in the effective management of breast cancer. Intense research has been conducted in the past decade to further explore its resistance mechanism, but still a lot of research will be needed to effectively alleviate this problem. Several biochemical factors and molecular pathways, such as the modulation of ER signaling, upregulation of growth factors had been observed as key factors for tamoxifen resistance (TR). After, initial therapy of five to ten years, breast cancer patients develops resistance towards this drug. The resistance leads to the development of other cancers like uterine cancer. Here, we briefly explore all the molecular events related to tamoxifen resistance and focus on its mechanism of action as well as other pharmacological approaches to better its beneficial effects in the treatment of breast carcinoma.

Physician and Patient Barriers to Breast Cancer Preventive Therapy

The uptake of selective estrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) for the primary prevention of breast cancer is low, despite their proven efficacy in several randomized clinical trials. This review summarizes the latest data on physicians' and women's barriers to breast cancer preventive therapy. Physicians' challenges include: identifying suitable candidates for preventive therapy, inadequate training and confidence in risk assessment and counselling, insufficient knowledge of risk-reducing medications, and lack of time. High-risk women fear medication side effects, and they often weigh experiences of others more heavily than statistical probabilities to guide their decision-making. Despite decision aid interventions to help women make an informed decision, acceptance of preventive therapy will remain low until: risk/benefit profiles are more favorable, physicians are better educated and skilled in having these discussions, and suitable biomarkers to monitor drug efficacy and better clinical risk prediction models to assess true individual risk are available.

Disease Interception: Myths, Mountains, and Mole Hills

Malignant diseases develop slowly over time and are often preceded by identifiable premalignancies. As malignancy progresses, so does genomic complexity and the ability of cancers to evade most therapeutic interventions. Accordingly, with some notable exceptions, a relatively low percentage of advanced cancers are effectively treated and even fewer are cured. Despite this appreciation, much less attention has been paid to intercepting the disease process compared with that of treating well-established and refractory disease. One frequently cited reason is that the pharmaceutical industry is not interested in these pursuits. In this commentary, we attempt to define the true hurdles, the degree of difficulty inherent in each, and some important approaches to be considered. Cancer Prev Res; 9(8); 635-7. ©2016 AACR.

Targeted conjugation of breast anticancer drug tamoxifen and its metabolites with synthetic polymers

Conjugation of antitumor drug tamoxifen and its metabolites, 4-hydroxytamxifen and ednoxifen with synthetic polymers poly(ethylene glycol) (PEG), methoxypoly (ethylene glycol) polyamidoamine (mPEG-PAMAM-G3) and polyamidoamine (PAMAM-G4) dendrimers was studied in aqueous solution at pH 7.4. Multiple spectroscopic methods, transmission electron microscopy (TEM) and molecular modeling were used to characterize the drug binding process to synthetic polymers. Structural analysis showed that drug-polymer binding occurs via both H-bonding and hydrophobic contacts. The order of binding is PAMAM-G4>mPEG-PAMAM-G3>PEG-6000 with 4-hydroxttamoxifen forming more stable conjugate than tamoxifen and endoxifen. Transmission electron microscopy showed significant changes in carrier morphology with major changes in the shape of the polymer aggregate as drug encapsulation occurred. Modeling also showed that drug is located in the surface and in the internal cavities of PAMAM with the free binding energy of -3.79 for tamoxifen, -3.70 for 4-hydroxytamoxifen and -3.69kcal/mol for endoxifen, indicating of spontaneous drug-polymer interaction at room temperature.

Development and in vitro assessment of alginate bilayer films containing the olive compound hydroxytyrosol as an alternative for topical chemotherapy

Topical chemotherapy is the application of cancer drugs directly onto the skin, which has become a standard treatment for basal cell carcinoma. Due to the promising results in the treatment of skin cancer, topical chemotherapy has recently been applied to breast cancer patients because some breast cancer tissues are only superficial. Hydroxytyrosol, a phenolic compound from olives that is present in high amounts in Hidrox(®) olive extract, has been shown to have a protective effect on normal cells and selective antitumor activities on cancerous cells. The aims of the present study were to develop an alginate bilayer film containing Hidrox(®) and to investigate its potential use as a topical chemotherapeutic agent. Alginate films were characterized for swelling and for physical, thermal, rheological, and mechanical properties. Drug content uniformity and in vitro drug release tests were also investigated. The alginate bilayer films containing Hidrox(®), HB2, showed controlled release of hydroxytyrosol at a flux of 0.094±0.009 mg/cm(2)/h. The results of the cytotoxic assay showed that the HB2 films were dose-dependent and could significantly reduce the growth of breast cancer cells (MCF-7) at 150 μg/mL for a cell viability of 29.34±4.64%. In conclusion, an alginate bilayer film containing Hidrox(®) can be a potential alternative for topical chemotherapeutic agent for skin and breast cancer treatment.

Molecular cancer prevention: Current status and future directions

The heterogeneity and complexity of advanced cancers strongly support the rationale for an enhanced focus on molecular prevention as a priority strategy to reduce the burden of cancer. Molecular prevention encompasses traditional chemopreventive agents as well as vaccinations and therapeutic approaches to cancer-predisposing conditions. Despite challenges to the field, we now have refined insights into cancer etiology and early pathogenesis; successful risk assessment and new risk models; agents with broad preventive efficacy (eg, aspirin) in common chronic diseases, including cancer; and a successful track record of more than 10 agents approved by the US Food and Drug Administration for the treatment of precancerous lesions or cancer risk reduction. The development of molecular preventive agents does not differ significantly from the development of therapies for advanced cancers, yet it has unique challenges and special considerations given that it most often involves healthy or asymptomatic individuals. Agents, biomarkers, cohorts, overall design, and endpoints are key determinants of molecular preventive trials, as with therapeutic trials, although distinctions exist for each within the preventive setting. Progress in the development and evolution of molecular preventive agents has been steadier in some organ systems, such as breast and skin, than in others. In order for molecular prevention to be fully realized as an effective strategy, several challenges to the field must be addressed. Here, the authors provide a brief overview of the context for and special considerations of molecular prevention along with a discussion of the results from major randomized controlled trials.

Cancer chemoprevention: Much has been done, but there is still much to do. State of the art and possible new approaches

Over the past three decades great efforts have been made in search of cancer chemoprevention strategies. The increase in knowledge of the long process from normal to cancer cell has enabled interventions in terms of lifestyle modifications, natural compounds or drugs to block or reverse the process. Great successes have been achieved, especially for breast and colorectal cancer. However, these strategies have yet to find clinical application on a large scale. In this article we identify the achievements, the pitfalls and the next steps to be taken to improve the efficacy and applicability of chemoprevention strategies. Among the crucial key points to be implemented are educational activities for physicians to appropriately disseminate the aim and indeed the culture of chemoprevention. It is essential to improve the risk-benefit balance, seeking the minimal active doses, intermittent schedules, a better characterization of the risk categories via a more personalized intervention based on individual characteristics, and ensure the containment of costs of public and private health prevention programs.