Design and Characterization of Maltoheptaose-b-Polystyrene Nanoparticles, as a Potential New Nanocarrier for Oral Delivery of Tamoxifen.

Tamoxifen citrate (TMC), a non-steroidal antiestrogen drug used for the treatment of breast cancer, was loaded in a block copolymer of maltoheptaose-b-polystyrene (MH-b-PS) nanoparticles, a potential drug delivery system to optimize oral chemotherapy. The nanoparticles were obtained from self-assembly of MH-b-PS using the standard and reverse nanoprecipitation methods. The MH-b-PS@TMC nanoparticles were characterized by their physicochemical properties, morphology, drug loading and encapsulation efficiency, and release kinetic profile in simulated intestinal fluid (pH 7.4). Finally, their cytotoxicity towards the human breast carcinoma MCF-7 cell line was assessed. The standard nanoprecipitation method proved to be more efficient than reverse nanoprecipitation to produce nanoparticles with small size and narrow particle size distribution. Moreover, tamoxifen-loaded nanoparticles displayed spherical morphology, a positive zeta potential and high drug content (238.6 ± 6.8 µg mL-1) and encapsulation efficiency (80.9 ± 0.4 %). In vitro drug release kinetics showed a burst release at early time points, followed by a sustained release profile controlled by diffusion. MH-b-PS@TMC nanoparticles showed higher cytotoxicity towards MCF-7 cells than free tamoxifen citrate, confirming their effectiveness as a delivery system for administration of lipophilic anticancer drugs.

Switching of hormone therapies in breast cancer women / Avaliação da mudança do esquema hormonioterápico em mulheres com câncer de mama

Abstract Objective The objective of the present study was to analyze the reasons that led to hormone therapies (HTs) regimen changes in women with breast cancer. Methods This was a retrospective cross-sectional study from a single-institution Brazilian cancer center with patient records diagnosed with breast cancer between January 2012 and January 2017. Results From 1,555 women who were in treatment with HT, 213 (13.7%) women had HT switched, either tamoxifen to anastrozole or vice-versa. Most women included in the present study who switched HT were > 50 years old, postmenopausal, Caucasian, and had at least one comorbidity. From the group with therapy change, 'disease progression' was reason of change in 124 (58.2%) cases, and in 65 (30.5%) patients, 'presence of side effects' was the reason. From those women who suffered with side effects, 24 (36.9%) had comorbidities. Conclusion The present study demonstrated a low rate of HT switch of tamoxifen to anastrozole. Among the reasons for changing therapy, the most common was disease progression, which includes cancer recurrence, metastasis or increased tumor. Side effects were second; furthermore, age and comorbidities are risk factors for side effects.

Resumo Objetivo O objetivo do presente estudo foi analisar os motivos que levaram às mudanças no esquema hormonioterápico (HT) em mulheres com câncer de mama. Métodos Estudo transversal retrospectivo realizado no Hospital da Mulher de Campinas e consequente pesquisa de prontuários de mulheres diagnosticados com câncer de mama entre janeiro de 2012 e janeiro de 2017. Resultados De 1.555 mulheres em tratamento com HT, 213 (13,7%) mulheres tiveram HT alterado, tamoxifeno para anastrozol ou vice-versa. A maioria das mulheres incluídas no presente estudo que tiveram mudança de HT tinha > 50 anos, estava na pós-menopausa, era caucasiana e tinha pelo menos uma comorbidade. Os principais motivos de troca de HT foram devido a 'progressão da doença', ocorrendo em 124 (58,2%) casos e a 'presença de efeitos colaterais' (n = 65; 30,5%). Das mulheres que sofreram efeitos colaterais, 24 (36,9%) apresentaram comorbidades. Conclusão O presente estudo demonstrou uma baixa taxa na alteração de tamoxifeno para anastrozol. Entre as razõesmais comuns para alterar a HT estava a progressão da doença, que inclui recorrência do câncer, metástase ou aumento do tumor. Os efeitos colaterais foram a segunda causa e, além disso, a idade e as comorbidades foram fatores de risco para efeitos colaterais.

Switching of Hormone Therapies in Breast Cancer Women.

OBJECTIVE: The objective of the present study was to analyze the reasons that led to hormone therapies (HTs) regimen changes in women with breast cancer. METHODS: This was a retrospective cross-sectional study from a single-institution Brazilian cancer center with patient records diagnosed with breast cancer between January 2012 and January 2017. RESULTS: From 1,555 women who were in treatment with HT, 213 (13.7%) women had HT switched, either tamoxifen to anastrozole or vice-versa. Most women included in the present study who switched HT were > 50 years old, postmenopausal, Caucasian, and had at least one comorbidity. From the group with therapy change, 'disease progression' was reason of change in 124 (58.2%) cases, and in 65 (30.5%) patients, 'presence of side effects' was the reason. From those women who suffered with side effects, 24 (36.9%) had comorbidities. CONCLUSION: The present study demonstrated a low rate of HT switch of tamoxifen to anastrozole. Among the reasons for changing therapy, the most common was disease progression, which includes cancer recurrence, metastasis or increased tumor. Side effects were second; furthermore, age and comorbidities are risk factors for side effects.

OBJETIVO: O objetivo do presente estudo foi analisar os motivos que levaram às mudanças no esquema hormonioterápico (HT) em mulheres com câncer de mama. MéTODOS: Estudo transversal retrospectivo realizado no Hospital da Mulher de Campinas e consequente pesquisa de prontuários de mulheres diagnosticados com câncer de mama entre janeiro de 2012 e janeiro de 2017. RESULTADOS: De 1.555 mulheres em tratamento com HT, 213 (13,7%) mulheres tiveram HT alterado, tamoxifeno para anastrozol ou vice-versa. A maioria das mulheres incluídas no presente estudo que tiveram mudança de HT tinha > 50 anos, estava na pós-menopausa, era caucasiana e tinha pelo menos uma comorbidade. Os principais motivos de troca de HT foram devido a 'progressão da doença', ocorrendo em 124 (58,2%) casos e a 'presença de efeitos colaterais' (n = 65; 30,5%). Das mulheres que sofreram efeitos colaterais, 24 (36,9%) apresentaram comorbidades. CONCLUSãO: O presente estudo demonstrou uma baixa taxa na alteração de tamoxifeno para anastrozol. Entre as razões mais comuns para alterar a HT estava a progressão da doença, que inclui recorrência do câncer, metástase ou aumento do tumor. Os efeitos colaterais foram a segunda causa e, além disso, a idade e as comorbidades foram fatores de risco para efeitos colaterais.

Asymptomatic postmenopausal women: what are the risk factors for endometrial malignancies? A multicentric retrospective study.

OBJECTIVE: To evaluate the prevalence and risk factors for endometrial malignancies in asymptomatic postmenopausal women. METHODS: Multicentric retrospective analytical study in two Brazilian Reference Centers. All women without postmenopausal bleeding who were submitted to hysteroscopy with biopsy were included (1665). Excluded women without anatomopathological results (625) and whose medical records were incomplete (37). The variables analyzed were age; parity; body mass index; duration of menopausal status; systemic arterial hypertension; diabetes mellitus; use of hormone replacement therapy; use of tamoxifen; duration of use of tamoxifen; endometrial thickness and biopsy results. RESULTS: The frequency of endometrial malignancies in asymptomatic postmenopausal women was 2.39%. Endometrial thickness ≥8 mm increased the chance of endometrial malignancies, even more, with an endometrial thickness ≥12.55 mm the chance of endometrial malignancies increased by 4.68 times (p < .001 and 95% CI: 1.99-11.03). CONCLUSION: The prevalence of endometrial malignancies was low and the only risk factor for endometrial malignancies in asymptomatic postmenopausal women was endometrial thickness.

Urinary Incontinence and Overactive Bladder Symptoms in Women with Breast Cancer Being Treated with Oral Hormone Therapy.

OBJECTIVE: The objective of the present study is to observe the frequency and severity of urinary symptoms in women with breast cancer (BC) being treated with oral hormone therapy, associating them to drug adherence. METHODS: The participants were interviewed once from June to October 2016. The evaluation of urinary symptoms was performed by two questionnaires: International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF) and International Consultation on Incontinence Questionnaire Overactive Bladder Module (ICIQ-OAB). Adherence was evaluated by the Morisky-Green method. Statistical analysis was performed by the Mann-Whitney test, linear regression, and Spearman correlation. RESULTS: Fifty-eight women were interviewed: 42 treated with tamoxifen and 16 with aromatase inhibitor. Twenty-seven women (46.5%) presented urinary incontinence symptoms and 15 (25.8%) presented stress urinary incontinence (SUI). Fourteen (24.1%) women had symptoms of overactive bladder (OAB). There was no statistical difference in symptoms between both treatments and duration of treatments. Higher scores in the ICIQ-SF questionnaire were associated with low/medium adherence and advanced age. Higher scores in the ICIQ-OAB questionnaire were associated with low/medium adherence. CONCLUSION: The present study showed a high prevalence of urinary symptoms, such as urinary incontinence and OAB, associated with low/medium adherence and older age in women with BC being treated with oral hormone therapy. Health professionals should be alert to these symptoms since it could influence life quality and adherence to treatment.

OBJETIVO: O objetivo do presente estudo foi observar a frequência e a gravidade dos sintomas urinários em mulheres com câncer de mama em uso de terapia hormonal oral, associando estes com a adesão ao tratamento. MéTODOS: As pacientes foram entrevistadas uma única vez, entre junho e outubro de 2016. A avaliação dos sintomas urinários foi realizada por dois questionários: International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF, na sigla em inglês) e o Questionário Sobre Bexiga Hiperativa (ICIQ-OAB, na sigla em inglês). A adesão foi avaliada pelo método Morisky-Green. A análise estatística foi realizada pelo teste de Mann-Whitney, regressão linear e correlação de Spearman. RESULTADOS: Foram entrevistadas 58 mulheres: 42 tratadas com tamoxifeno e 16 com inibidor de aromatase. Vinte e sete mulheres (46,5%) apresentaram sintomas de incontinência urinária (IU) e 15 (25,8%) apresentaram incontinência urinária por estresse (IUS). Quatorze (24,1%) das mulheres tinham sintomas de bexiga hiperativa. Não houve diferença estatística nos sintomas entre os tratamentos e a duração dos tratamentos. Os escores mais elevados no questionário ICIQ-SF estiveram associados à baixa/média adesão e à idade avançada. Os escores mais elevados no questionário da ICIQ-OAB foram associados à baixa/média adesão. CONCLUSãO: O presente estudo mostrou alta prevalência de sintomas urinários, como IU e bexiga hiperativa, associadas à baixa/média adesão e à idade mais avançada em mulheres com câncer de mama em tratamento com hormonioterapia oral. Os profissionais de saúde devem estar atentos a esses sintomas, pois eles podem influenciar a qualidade de vida e a adesão ao tratamento.

Urinary incontinence and overactive bladder symptoms in women with breast cancer being treated with oral hormone therapy / Incontinência urinária e sintomas de bexiga hiperativa em mulheres com câncer de mama em tratamento com terapia hormonal oral

Abstract Objective: The objective of the present study is to observe the frequency and severity of urinary symptoms in women with breast cancer (BC) being treated with oral hormone therapy, associating them to drug adherence. Methods: The participants were interviewed once from June to October 2016. The evaluation of urinary symptoms was performed by two questionnaires: International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF) and International Consultation on Incontinence Questionnaire Overactive Bladder Module (ICIQ-OAB). Adherence was evaluated by the Morisky-Green method. Statistical analysis was performed by the Mann-Whitney test, linear regression, and Spearman correlation. Results: Fifty-eight women were interviewed: 42 treated with tamoxifen and 16 with aromatase inhibitor. Twenty-seven women (46.5%) presented urinary incontinence symptoms and 15 (25.8%) presented stress urinary incontinence (SUI). Fourteen (24.1%) women had symptoms of overactive bladder (OAB). There was no statistical difference in symptoms between both treatments and duration of treatments. Higher scores in the ICIQ-SF questionnaire were associated with low/medium adherence and advanced age. Higher scores in the ICIQ-OAB questionnaire were associated with low/medium adherence. Conclusion: The present study showed a high prevalence of urinary symptoms, such as urinary incontinence and OAB, associated with low/medium adherence and older age in women with BC being treated with oral hormone therapy. Health professionals should be alert to these symptoms since it could influence life quality and adherence to treatment.

Resumo Objetivo: O objetivo do presente estudo foi observar a frequência e a gravidade dos sintomas urinários em mulheres com câncer de mama em uso de terapia hormonal oral, associando estes com a adesão ao tratamento. Métodos: As pacientes foram entrevistadas uma única vez, entre junho e outubro de 2016. A avaliação dos sintomas urinários foi realizada por dois questionários: International Consultation on Incontinence Questionnaire - Short Form (ICIQ-SF, na sigla em inglês) e o Questionário Sobre Bexiga Hiperativa (ICIQ-OAB, na sigla em inglês). A adesão foi avaliada pelo método Morisky-Green. A análise estatística foi realizada pelo teste de Mann-Whitney, regressão linear e correlação de Spearman. Resultados: Foram entrevistadas 58 mulheres: 42 tratadas com tamoxifeno e 16 com inibidor de aromatase. Vinte e sete mulheres (46,5%) apresentaram sintomas de incontinência urinária (IU) e 15 (25,8%) apresentaram incontinência urinária por estresse (IUS). Quatorze (24,1%) das mulheres tinham sintomas de bexiga hiperativa. Não houve diferença estatística nos sintomas entre os tratamentos e a duração dos tratamentos. Os escores mais elevados no questionário ICIQ-SF estiveram associados à baixa/média adesão e à idade avançada. Os escores mais elevados no questionário da ICIQ-OAB foram associados à baixa/média adesão. Conclusão: O presente estudo mostrou alta prevalência de sintomas urinários, como IU e bexiga hiperativa, associadas à baixa/média adesão e à idade mais avançada em mulheres com câncer de mama em tratamento com hormonioterapia oral. Os profissionais de saúde devem estar atentos a esses sintomas, pois eles podem influenciar a qualidade de vida e a adesão ao tratamento.

Continuous Exposure of Breast Cancer Cells to Tamoxifen Upregulates GPER-1 and Increases Cell Proliferation.

GPER-1 is a novel membrane sited G protein-coupled estrogen receptor. Clinical studies have shown that patients suffering an estrogen receptor α (ERα)/GPER-1 positive, breast cancer have a lower survival rate than those who have developed ERα-positive/GPER-1 negative tumors. Moreover, absence of GPER-1 improves the prognosis of patients treated with tamoxifen, the most used selective estrogen receptor modulator to treat ERα-positive breast cancer. MCF-7 breast cancer cells were continuously treated with 1,000 nM tamoxifen for 7 days to investigate its effect on GPER-1 protein expression, cell proliferation and intracellular [Ca2+]i mobilization, a key signaling pathway. Breast cancer cells continuously treated with tamoxifen, exhibited a robust [Ca2+]i mobilization after stimulation with 1,000 nM tamoxifen, a response that was blunted by preincubation of cells with G15, a commercial GPER-1 antagonist. Continuously treated cells also displayed a high [Ca2+]i mobilization in response to a commercial GPER-1 agonist (G1) and to estrogen, in a magnitude that doubled the response observed in untreated cells and was almost completely abolished by G15. Proliferation of cells continuously treated with tamoxifen and stimulated with 2,000 nM tamoxifen, was also higher than that observed in untreated cells in a degree that was approximately 90% attributable to GPER-1. Finally, prolonged tamoxifen treatment did not increase ERα expression, but did overexpress the kinin B1 receptor, another GPCR, which we have previously shown is highly expressed in breast tumors and increases proliferation of breast cancer cells. Although we cannot fully extrapolate the results obtained in vitro to the patients, our results shed some light on the occurrence of drug resistance in breast cancer patients who are ERα/GPER-1 positive, have been treated with tamoxifen and display low survival rate. Overexpression of kinin B1 receptor may explain the increased proliferative response observed in breast tumors under continuous treatment with tamoxifen.

Post-marketing assessment of generic tamoxifen in Brazilian breast cancer patients.

Generic formulations of tamoxifen are commonly prescribed to oestrogen receptor-positive breast cancer patients at the Brazilian National Cancer Institute (INCA). We carried out a post-marketing surveillance of the generic tamoxifen formulation in current use at INCA, by comparing plasma concentrations of the parent drug and metabolites obtained with the generic vs the reference formulation. Thirty patients participated in an open-label, bracketed protocol, comprising 3 successive phases of 30-32 days each: the generic formulation was used in phases 1 and 3 and the reference formulation in phase 2. Two blood samples were collected in the last 4 days of each phase, for LC-MS/MS quantification of tamoxifen and metabolites in plasma. The median plasma concentrations (ng/mL) for the reference formulation were as follows: tamoxifen, 135.0 (CI 95% 114.2-155.8); endoxifen, 35.3 (30.0-40.8); and 4-hydroxytamoxifen, 4.8 (4.2-5.4). The endoxifen/tamoxifen plasma concentration ratio was 0.27 (0.21-0.25). ANOVA detected no statistically significant difference in plasma concentrations of tamoxifen, metabolites or the endoxifen/tamoxifen ratio among the three phases. The genetic component (rGC) of the CYP2D6-mediated conversion of tamoxifen into endoxifen, estimated using the repeated drug administration procedure across the three phases, was 0.87, pointing to an important component of genetic variability. In conclusion, this first post-marketing surveillance trial of oncologic generic drugs carried out in Brazilian patients verified the switchability between the reference and the generic tamoxifen formulation currently used at our institution. The adopted bracketed protocol adds confidence to this conclusion and may serve as a frame for future trials of post-marketing assessment of other generic drug products.

iRGD-guided tamoxifen polymersomes inhibit estrogen receptor transcriptional activity and decrease the number of breast cancer cells with self-renewing capacity.

BACKGROUND: Tamoxifen (Tam) is the most frequent treatment for estrogen receptor (ER) positive breast cancer. We recently showed that fibronectin (FN) leads to Tam resistance and selection of breast cancer stem cells. With the aim of developing a nanoformulation that would simultaneously tackle ER and FN/ß1 integrin interactions, we designed polyethylene glycol-polycaprolactone polymersomes polymersomes (PS) that carry Tam and are functionalized with the tumor-penetrating iRGD peptide (iRGD-PS-Tam). RESULTS: Polyethylene glycol-polycaprolactone PS were assembled and loaded with Tam using the hydration film method. The loading of encapsulated Tam, measured by UPLC, was 2.4 ± 0.5 mol Tam/mol polymer. Physicochemical characterization of the PS demonstrated that iRGD functionalization had no effect on morphology, and a minimal effect on the PS size and polydispersity (176 nm and Pdi 0.37 for iRGD-TAM-PS and 171 nm and Pdi 0.36 for TAM-PS). iRGD-PS-Tam were taken up by ER+ breast carcinoma cells in 2D-culture and exhibited increased penetration of 3D-spheroids. Treatment with iRGD-PS-Tam inhibited proliferation and sensitized cells cultured on FN to Tam. Mechanistically, treatment with iRGD-PS-Tam resulted in inhibition ER transcriptional activity as evaluated by a luciferase reporter assay. iRGD-PS-Tam reduced the number of cells with self-renewing capacity, a characteristic of breast cancer stem cells. In vivo, systemic iRGD-PS-Tam showed selective accumulation at the tumor site. CONCLUSIONS: Our study suggests iRGD-guided delivery of PS-Tam as a potential novel therapeutic strategy for the management of breast tumors that express high levels of FN. Future studies in pre-clinical in vivo models are warranted.

Dynamic Effects of CYP2D6 Genetic Variants in a Set of Poor Metaboliser Patients with Infiltrating Ductal Cancer Under Treatment with Tamoxifen.

Breast cancer is a group of multigenic diseases. It is the most common cancer diagnosed among women worldwide and is often treated with tamoxifen. Tamoxifen is catalysed by cytochrome P450 2D6 (CYP2D6), and inter-individual variations in the enzyme due to single nucleotide polymorphisms (SNPs) could alter enzyme activity. We evaluated SNPs in patients from Colombia in South America who were receiving tamoxifen treatment for breast cancer. Allelic diversity in the CYP2D6 gene was found in the studied population, with two patients displaying the poor-metaboliser phenotype. Molecular dynamics and trajectory analyses were performed for CYP2D6 from these two patients, comparing it with the common allelic form (CYP2D6*1). Although we found no significant structural change in the protein, its dynamics differ significantly from those of CYP2D6*1, the effect of such differential dynamics resulting in an inefficient enzyme with serious implications for tamoxifen-treated patients, increasing the risk of disease relapse and ineffective treatment.

Retroperitoneal fibrosis. Steroid treatment response seems to depend on its association to IgG4 related disease.

Retroperitoneal fibrosis (RF) is part of a rare fibrosclerotic disorder. Oral steroids are the initial treatment. Steroid combination with other immunosupressants is used in refractory cases. Steroids refractoriness has been observed in chronic cases. Some cases of RF represent a manifestation of the IgG4 related disease (IgG4-RD) that is associated to a dramatic response to steroid therapy. It is uncertain if RF́s treatment response differs according to its association with IgG4-RD. We hypothesize that RF́s treatment response to steroids depends on the association with IgG4-RD, thus, we collected and compared clinical data from 10 RF cases; 6 male, mean age 50.6 (±16.15 SD) years. Mean FU was 28 (±25.7 SD) months. According to IgG4 levels, patients were categorized as idiopathic RF (IRF n = 5) or RF-IgG4-RD (n = 5). Therapy response was categorized as complete, partial, stable disease, recurrence or non-response. Nine cases received initial therapy with prednisone; complete response was achieved in 4 RF-IgG4 RD. The remaining 5 cases (1 RF-IgG4RD and 4 IRF) underwent a 2nd line therapy; 4 prednisone + tamoxifen and 1 prednisone + azathioprine. Prednisone + tamoxifen combination achieved complete response in 1 case (RF-IgG4RD), partial response in 1 IRF; in 1 IRF case, disease remained stable and 1 did not respond. The prednisone + azathioprine treatment achieved complete response. At follow-up all patients remained stable and no recurrence was registered. These observations suggest and support the hypothesis that response to steroid monotherapy depends on the association of RF with IgG4, suggesting that IRF cases might benefit from initial combination therapies instead of steroid monotherapy.

Tamoxifen and meglumine antimoniate combined therapy in cutaneous leishmaniasis patients: a randomised trial.

OBJECTIVES: There is a clear need for new strategies of leishmaniasis treatment. This work was conducted to evaluate the efficacy of the co-administration of tamoxifen and meglumine antimoniate (SbV ) in a phase II pilot clinical trial in localised cutaneous leishmaniasis patients. METHODS: A randomised controlled pilot clinical trial was conducted to evaluate the efficacy and safety of oral (40 mg/day for 20 days) or topical tamoxifen (0.1% tamoxifen citrate for 20 days) combined with meglumine antimoniate (20 mg SbV /kg/day for 20 days) vs. a standard SbV protocol (20 mg/kg/day for 20 days) for the treatment of cutaneous leishmaniasis. Primary outcome was complete epithelisation of the lesion 6 months after the end of treatment. Secondary outcomes were lesion healing 2 months after the end of treatment and frequency and severity of adverse events. RESULTS: A total of 38 subjects were included in the trial, 15 were treated with standard SbV and 23 with the combination of tamoxifen and SbV . Of the patients treated with the co-administration scheme, 12 received tamoxifen orally and 11 were treated with topical tamoxifen. Tamoxifen administered by the oral or topical routes was well tolerated. Cure rates 6 months after the end of treatment per intention to treat were 40% in the group treated with the standard SbV scheme, and 36.4% and 58%, respectively, for groups treated with SbV plus topical or oral tamoxifen. CONCLUSIONS: In the doses and schemes used in this study, co-administration of oral tamoxifen and SbV resulted in higher cure rates in comparison with the standard scheme of treatment, although not to statistically significant levels.

Multifunctionalized biocatalytic P22 nanoreactor for combinatory treatment of ER+ breast cancer.

BACKGROUND: Tamoxifen is the standard endocrine therapy for breast cancers, which require metabolic activation by cytochrome P450 enzymes (CYP). However, the lower and variable concentrations of CYP activity at the tumor remain major bottlenecks for the efficient treatment, causing severe side-effects. Combination nanotherapy has gained much recent attention for cancer treatment as it reduces the drug-associated toxicity without affecting the therapeutic response. RESULTS: Here we show the modular design of P22 bacteriophage virus-like particles for nanoscale integration of virus-driven enzyme prodrug therapy and photodynamic therapy. These virus capsids carrying CYP activity at the core are decorated with photosensitizer and targeting moiety at the surface for effective combinatory treatment. The estradiol-functionalized nanoparticles are recognized and internalized into ER+ breast tumor cells increasing the intracellular CYP activity and showing the ability to produce reactive oxygen species (ROS) upon UV365 nm irradiation. The generated ROS in synergy with enzymatic activity drastically enhanced the tamoxifen sensitivity in vitro, strongly inhibiting tumor cells. CONCLUSIONS: This work clearly demonstrated that the targeted combinatory treatment using multifunctional biocatalytic P22 represents the effective nanotherapeutics for ER+ breast cancer.

Topical tamoxifen in the therapy of cutaneous leishmaniasis.

The aims of the present work were to test the effect of tamoxifen administered topically and the therapeutic efficacy of tamoxifen and pentavalent antimonial combinations in an experimental model of cutaneous leishmaniasis. BALB/c mice infected with a luciferase expressing line of Leishmania amazonensis were treated with topical tamoxifen in two different formulations (ethanol or oil-free cream) as monotherapy or in co-administration with pentavalent antimonial. Treatment efficacy was evaluated by lesion size and parasite burden, quantified through luminescence, at the end of treatment and 4 weeks later. Topical tamoxifen, formulated in ethanol or as a cream, was shown to be effective. The interaction between tamoxifen and pentavalent antimonial was additive in vitro. Treatment with combined schemes containing tamoxifen and pentavalent antimonial was effective in reducing lesion size and parasite burden. Co-administration of tamoxifen and pentavalent antimonial was superior to monotherapy with antimonial.

Morphological and morphometric analysis of the effects of intralesional tamoxifen on keloids.

The aim of this study was to evaluate the effect of intralesional tamoxifen on keloids, particularly on the concentration of fibroblasts, dermal inflammatory infiltrate, and collagen degeneration. A prospective study was carried out to evaluate keloids in 13 patients of both genders pre- and post-treatment with intralesional tamoxifen. Two samples of keloid lesions were obtained by 4-mm punch biopsies during the study: the first at the time of diagnostic confirmation of keloid and the other eight weeks later at the end of intralesional tamoxifen treatment. The biopsy samples were placed in 10% buffered formalin for HE staining and morphological and morphometric study. The degree of collagen fiber reduction and inflammatory infiltration were analyzed. Student's t-test was used for statistical analysis of the mean number of fibroblasts before and following tamoxifen treatment ( P < 0.05). The degree of collagen fiber reduction and inflammatory infiltration were absent before treatment and present in 100% of cases after treatment, while the mean number of fibroblasts was significantly lower after intralesional tamoxifen treatment ( P < 0.0001). We conclude that intralesional administration of tamoxifen promoted an inflammatory stimulus and collagen fiber reduction as well as a significant reduction in the number of fibroblasts that produce collagen. Impact statement Effective treatment of keloid that is a commonly recurrent dermatosis is very difficult, even after standard treatment. Standard treatment consists of partial resection of the lesion (shaving excision), in addition to local corticosteroid injection. Therefore, there is interest in alternative forms of topical treatment, e.g., selective estrogen receptor modulators, particularly tamoxifen has demonstrated in vitro studies to be a promising drug. Nevertheless, there is scarcity of publications on the effects of intralesional tamoxifen on keloids have been found, leading us to the conception of the present study. In this study, tamoxifen has proven to be an interesting alternative drug for the topical treatment of keloid, allowing us to conclude that the intralesional application of tamoxifen in keloids promotes a variable but ever-present inflammatory stimulus, associated with intense reduction of collagen fiber, in addition to a significant decrease in the number of fibroblasts that produce collagen and are involved in disease maintenance.

Biocatalytic virus capsid as nanovehicle for enzymatic activation of Tamoxifen in tumor cells.

Most of the drugs used in chemotherapy should be activated by a transformation catalyzed by cytochrome P450 (CYP) enzymes. In this work, bacteriophage P22 virus-like particles (VLPs) containing CYP activity, immunologically inert and functionalized in order to be recognized by human cervix carcinoma cells and human breast adenocarcinoma cells were designed. The CYP was encapsulated inside the virus capsid obtained from the bacteriophage P22. CYP and coat protein were both heterologously expressed in E. coli. The VLPs with enzymatic activity were covered with polyethylene glycol that was functionalized in its distal end with folic acid in order to be recognized by folate receptors exhibited on tumor cells. The capacity of biocatalytic VLPs to be recognized and internalized into tumor cells is demonstrated. The VLP-treated cells showed enhanced capacity for the transformation of the pro-drug tamoxifen, which resulted in an increase of the cell sensitivity to this oncological drug. In this work, the potential use of biocatalytic VLPs vehicles as a delivery system of medical relevant enzymes is clearly demonstrated. In addition to cancer treatment, this technology also offers an interesting platform as nano-bioreactors for intracellular delivery of enzymatic activity for other diseases originated by the lack of enzymatic activity.

Evaluation of Ki-67 antigen expression in the vaginal epithelium of castrated female rats treated with raloxifene and tamoxifen: a comparative study.

OBJECTIVE: The aim of this study was to evaluate the effects of raloxifene and tamoxifen on Ki-67 antigen expression in the vaginal epithelium of castrated rats. MATERIAL AND METHODS: Thirty-nine virgin, adult, castrated female Wistar-Hannover rats were randomly divided into three groups: Group I (control, n = 13), Group II (raloxifene, n = 13) and Group III (tamoxifen, n = 13). After confirmation of their hypoestrogenic state, the rats were given 0.5 ml of propylene glycol (vehicle), 750 µg of raloxifene or 250 µg of tamoxifen, respectively, by gavage, for 30 days. On the 31st day, the rats were euthanized and their vaginas removed and fixed in 10% buffered formalin for of Ki-67 immunohistochemical evaluation. Data were analyzed using Levene's test and Tukey's method (p < 0.05). RESULTS: Mean Ki-67 expression in groups I, II and III was 27 ± 2.6, 32.3 ± 1.9 and 43.7 ± 3.5, respectively. In Group III (tamoxifen), there was a greater proportion of stained cells compared to Groups I and II (p < 0.0003), with no statistically significant difference between Groups I and II (p = 0.3626). CONCLUSIONS: The present results show that tamoxifen significantly increased cell proliferation in the vaginal epithelium of the castrated rats and no difference between the raloxifene and control groups.

Efficacy of tamoxifen and miltefosine combined therapy for cutaneous leishmaniasis in the murine model of infection with Leishmania amazonensis.

OBJECTIVES: The objective of this study was to characterize in vitro interactions and evaluate the antileishmanial activity of tamoxifen and miltefosine combinations. METHODS: Interactions between drugs were evaluated in vitro against Leishmania amazonensis promastigotes and intracellular amastigotes by a modified isobologram method. Four different drug ratios were used to calculate the FIC index (FICI) and the mean sum of FICI. Treatment of L. amazonensis-infected BALB/c mice was initiated 4 weeks post-infection. Mice were treated with the half-maximal effective dose (ED50) or half the ED50 of tamoxifen and miltefosine orally for 15 days. Efficacy was evaluated by lesion growth and parasite burden measured through luciferase detection at the end of treatment and 30 days later. Characterization of growth curves and stepwise increase in drug concentrations in vitro were used to measure survival and resistance selection of parasite populations submitted to combination treatment. RESULTS: No in vitro interactions between tamoxifen and miltefosine were found. In infected mice, the combination of tamoxifen and miltefosine at doses corresponding to half the ED50 was more effective than monotherapy with either tamoxifen or miltefosine. When the ED50 was employed, the efficacy of the combination was equivalent to miltefosine monotherapy. In vitro, tamoxifen was able to retard or suppress the growth of parasites treated with miltefosine. CONCLUSIONS: In vitro and in vivo studies revealed no interaction between tamoxifen and miltefosine. Tamoxifen was able to hinder the emergence of miltefosine resistance.