Incidence and management of side effects associated with aromatase inhibitors in the adjuvant treatment of breast cancer in postmenopausal women

Hormones as a double-edged sword: the role of hormones in cancer progression and the potential of targeted hormone therapies

Cancer remains a significant cause of mortality in the world, with increasing prevalence worldwide. There are numerous treatments ranging from surgery to chemotherapy and radiotherapy, but since cancer is a heterogeneous disease, only few patients possibly respond to treatments. However, it opens a huge space for the advent of targeted therapies such as hormone therapy, immunotherapy, and target-specific drugs. Hormonal therapy using hormone agonists/antagonists or hormone receptor inhibitors-called the next-generation hormonal agents-hits distinct hormonal pathways that are involved in breast, prostate and ovarian cancer. Preliminary results show that through combination of drugs, it is possible that the synergistic effects may actually lead to better survival than with the use of single drugs. With manageable adverse effects, hormonal therapy offers much hope for treatment of this rather challenging malignancy of the hormone-sensitive cancers, especially in combination with other treatments.

Recent trends in the design and delivery strategies of ruthenium complexes for breast cancer therapy

As the most frequent and deadly type of cancer in women, breast cancer has a high propensity to spread to the brain, bones, lymph nodes, and lungs. The discovery of cisplatin marked the beginning of the development of anticancer metal-based medications, although the drug's severe side effects have limited its usage in clinical settings. The remarkable antimetastatic and anticancer activity of different ruthenium complexes such as NAMI-A, KP1019, KP1339, etc. reported in the 1980s has bolstered the discovery of ruthenium complexes with various types of ligands for anticancer applications. The review meticulously elucidates the cytotoxic and antimetastatic potential of reported ruthenium complexes against breast cancer cells. Notably, arene-based and cyclometalated ruthenium complexes emerge as standout candidates, showcasing remarkable potency with notably low IC50 values. These findings underscore the promising therapeutic avenues offered by ruthenium-based compounds, particularly in addressing the challenges posed by conventional treatments in refractory or aggressive breast cancer subtypes. Moreover, the review comprehensively integrates a spectrum of ruthenium complexes, spanning traditional metal complexes to nano-based formulations and light-activated variants, underscoring the versatility and adaptability of ruthenium chemistry in breast cancer therapy.

Promoting physical activity through supervised vs motivational behavior change interventions in breast cancer survivors on aromatase inhibitors (PAC-WOMAN): protocol for a 3-arm pragmatic randomized controlled trial

BACKGROUND

Aromatase inhibitors (AI) are frequently used to treat hormone-receptor-positive breast cancer, but they have multiple adverse effects (e.g., osteoporosis, arthralgia), resulting in premature therapy discontinuation/switch. Physical activity (PA) can attenuate these negative effects and improve quality of life (QoL). However, most cancer survivors fail to perform/sustain adequate PA levels, especially in the long-term. Theory-based interventions, using evidence-based behavior change techniques, aimed at promoting long-term behavior change in breast cancer survivors are effective, but remain scarce and fail to promote self-regulatory skills and better-quality motivations associated with sustained PA adoption. This paper describes the design of the PAC-WOMAN trial, which will test the long-term effectiveness and cost-effectiveness of two state of the art, group-based interventions encouraging sustained changes in PA, sedentary behavior, and QoL. Additional aims include examining the impact of both interventions on secondary outcomes (e.g., body composition, physical function), and key moderators/mediators of short and long-term changes in primary outcomes.

METHODS

A 3-arm pragmatic randomized controlled trial, involving a 4-month intervention and a 12-month follow-up, will be implemented, in a real exercise setting, to compare: 1) brief PA counseling/motivational intervention; 2) structured exercise program vs. waiting-list control group. Study recruitment goal is 122 hormone-receptor-positive breast cancer survivors (stage I-III), on AI therapy (post-primary treatment completion) ≥ 1 month, ECOG 0-1. Outcome measures will be obtained at baseline, 4 months (i.e., post-intervention), 10 and 16 months. Process evaluation, analyzing implementation determinants, will also be conducted.

DISCUSSION

PAC-WOMAN is expected to have a relevant impact on participants PA and QoL and provide insights for the improvement of interventions designed to promote sustained adherence to active lifestyle behaviors, facilitating its translation to community settings.

TRIAL REGISTRATION

April 20, 2023 - NCT05860621. April 21, 2023 - https://doi.org/10.17605/OSF.IO/ZAQ9N April 27, 2023 - UMIN000050945.

Adherence to Adjuvant Endocrine Therapy in Breast Cancer Patients

BACKGROUND

Adjuvant endocrine therapy (AET) reduces breast cancer recurrence and mortality of women with hormone-receptor-positive tumors, but poor adherence remains a significant problem. The aim of this study was to analyze AET side effects and their impact on adherence to treatment.

METHODS

A total of 373 breast cancer patients treated with AET filled out a specific questionnaire during their follow up visits at the Breast Unit of our Centre.

RESULTS

Side effects were reported by 81% of patients, 84% of those taking tamoxifen and 80% of those taking aromatase inhibitors (AIs). The most common side effect in the tamoxifen group was hot flashes (55.6%), while in the AI group it was arthralgia (60.6%). The addition of GnRH agonists to both tamoxifen and AI significantly worsened all menopausal symptoms. Overall, 12% of patients definitively discontinued AET due to side effects, 6.4% during the first 5 years and 24% during extended therapy. Patients who had previously received chemotherapy or radiotherapy reported a significantly lower discontinuation rate.

CONCLUSIONS

AET side effects represent a significant problem in breast cancer survivors leading to irregular assumption and discontinuation of therapy. Adherence to AET may be improved by trustful patient-physician communication and a good-quality care network.

Venous and arterial thrombosis associated with abemaciclib therapy for metastatic breast cancer

BACKGROUND

The CDK4/6 inhibitor abemaciclib is a mainstay of treatment for hormone receptor-positive breast cancer. However, increased venous thromboembolism (VTE) rates in multiple clinical trials resulted in a black-box warning for this agent. Thrombosis rates in unselected real-world populations receiving abemaciclib remain ill defined.

METHODS

A multicenter observational cohort study was conducted of patients with metastatic breast cancer receiving abemaciclib. The primary end point was thrombosis during treatment or within 30 days of discontinuation. Multivariable logistic models assessed predictors of VTE, and a multivariable Cox proportional hazards model assessed mortality.

RESULTS

A total of 364 patients were included, with a median treatment duration of 5.5 months. Twenty-six patients developed 27 (7.4%) thrombotic events (17 VTE, nine arterial thrombosis, and one with both events). No baseline characteristics were associated with increased VTE risk in multivariable modeling. Patients developing VTE during therapy had a higher risk of death than those who did not (hazard ratio, 2.09; 95% CI, 1.07-4.13). Median survival in patients who developed VTE compared with those who did not was 9.6 vs 25.8 months, respectively. The rate of VTE and any thrombosis during abemaciclib therapy was 9.1 and 13.7 events per 100 person-years, respectively, which is notably higher than rates observed in clinical trials.

CONCLUSIONS

In a real-world setting, abemaciclib was associated with a VTE rate approximately two-fold greater than the already elevated rates reported in the MONARCH trials. Patients developing thrombosis on abemaciclib had a significantly higher risk of death. Given these findings, studies evaluating the role of thromboprophylaxis in patients receiving abemaciclib are needed.

THRIVE intervention development: using participatory action research principles to guide a mHealth app-based intervention to improve oncology care

Background:

Women with hormone receptor-positive, early-stage breast cancer who adhere to adjuvant endocrine therapy (AET) reduce the risk of cancer recurrence and mortality. AET, however, is associated with adverse symptoms that often result in poor adherence. We applied participatory action research (PAR) principles to conduct focus groups and interviews to refine and enhance a web-enabled app intervention that facilitates patient-provider communication about AET-related symptoms and other barriers to adherence.

Methods:

We conducted four focus groups with women with early-stage breast cancer on AET (N=28), stratified by race (Black and White) and length of time on AET (<6 months and >6 months), to determine preferences and refine the app-based intervention. A fifth mixed-race focus group was convened (N=6) to refine THRIVE app content using high-fidelity mock-ups and to develop new, tailored feedback messages. We also conducted interviews with oncology nurses (N=5) who participated in the THRIVE randomized controlled trial.

Results:

Participants reported preferences for weekly reminder messages to use the THRIVE app, a free-text option to write in AET-related symptoms, and app aesthetics. Other requested app features included: a body map for identifying pain, sleep and dental problems on the symptom list, a dashboard, tailored feedback messages, and information about social support resources. Participants also developed new intervention messages, decided which messages to keep, and edited language for appropriateness and sensitivity. They also discussed the type of electronic pill monitor and incentive plan to be used in the intervention. Nurses reported THRIVE alerts integrated seamlessly into their clinical workflow and increased patient-provider communication, facilitating quicker response to patients’ reported symptoms. Nurses reported no negative feedback or usability concerns with the app.

Conclusions:

THRIVE app content reflects researchers’ partnership with a racially diverse sample of breast cancer survivors and healthcare providers and adherence to participatory design by incorporating patient-requested app features, app aesthetics, and message content. The app has the potential to improve AET adherence and quality of life among breast cancer survivors and reduce disparities in mortality rates for Black women by facilitating communication with healthcare providers.

Treatment interruption and discontinuation of hormonal therapy in hormone receptor-positive breast cancer patients

PURPOSE

To investigate predictors of treatment interruption and early discontinuation of adjuvant hormonal therapy (HT) in a retrospective cohort of women with newly diagnosed hormone receptor-positive (HR +) breast cancer.

METHODS

Eligible cases were identified from a single institutional tumor registry from 2009 to 2015. Patients were followed from initiation of adjuvant HT for a minimum of one year through December 1, 2016. Predictors of treatment interruption or early discontinuation were analyzed with Cox proportional hazards regression models.

RESULTS

With a median follow-up time of 3.0 years (IQR 1.5-4.5), 22 women (10.9%) discontinued HT early and 47 (23.4%) had at least one treatment interruption of > 14 days. Adjusted Cox proportional hazards regression models showed that women with pre-existing affective disorders were more likely to discontinue therapy early (HR 3.15; 95% CI 1.35-7.37), while those with pre-existing chronic pain disorders were at increased risk for treatment interruption (HR 2.24; 95% CI 1.20-4.19). HT-related symptoms were the most commonly reported reason for HT interruption or discontinuation. Women who experienced severe treatment-related symptoms were at increased risk for both HT interruption (HR 2.64; 95% CI 1.07-6.50) and HT discontinuation (HR 3.48; 95% CI 1.20-10.1).

CONCLUSIONS

This study showed that HT interruptions and discontinuation were common, often associated with HT-related symptoms. Clinicians caring for breast cancer patients on HT should monitor closely for treatment-emergent symptoms, especially women with pre-existing disorders, and support them to continue therapy through aggressive symptom management and other patient-centered approaches.

Rationally Designed Ruthenium Complexes for Breast Cancer Therapy

Since the discovery of the anticancer potential of ruthenium-based complexes, several species were reported as promising candidates for the treatment of breast cancer, which accounts for the greatest number of new cases in women every year worldwide. Among these ruthenium complexes, species containing bioactive ligand(s) have attracted increasing attention due to their potential multitargeting properties, leading to anticancer drug candidates with a broader range of cellular targets/modes of action. This review of the literature aims at providing an overview of the rationally designed ruthenium-based complexes that have been reported to date for which ligands were carefully selected for the treatment of hormone receptor positive breast cancers (estrogen receptor (ER+) or progesterone receptor (PR+)). In addition, this brief survey highlights some of the most successful examples of ruthenium complexes reported for the treatment of triple negative breast cancer (TNBC), a highly aggressive type of cancer, regardless of if their ligands are known to have the ability to achieve a specific biological function.

Estrogens and breast cancer: Mechanisms involved in obesity-related development, growth and progression

Obesity is a risk factor for estrogen receptor-positive (ER+) breast cancer after menopause. The pro-proliferative effects of estrogens are well characterized and there is a growing body of evidence to also suggest an important role in tumorigenesis. Importantly, obesity not only increases the risk of breast cancer, but it also increases the risk of recurrence and cancer-associated death. Aromatase is the rate-limiting enzyme in estrogen biosynthesis and its expression in breast adipose stromal cells is hypothesized to drive the growth of breast tumors and confer resistance to endocrine therapy in obese postmenopausal women. The molecular regulation of aromatase has been characterized in response to many obesity-related molecules, including inflammatory mediators and adipokines. This review is aimed at providing an overview of our current knowledge in relation to the regulation of estrogens in adipose tissue and their role in driving breast tumor development, growth and progression.

Clinical Benefits of Acupuncture for the Reduction of Hormone Therapy-Related Side Effects in Breast Cancer Patients: A Systematic Review

Importance. Acupuncture can help reduce unpleasant side effects associated with endocrine therapy for breast cancer. Nevertheless, comprehensive evaluation of current evidence from randomized controlled trials(RCTs) is lacking. Objective. To estimate the efficacy of acupuncture for the reduction of hormone therapy-related side effects in breast cancer patients. Evidence review. RCTs of acupuncture in breast cancer patients that examined reductions in hormone therapy–related side effects were retrieved from PubMed, EMBASE, Web of Science, Ovid MEDLINE, and Cochrane Library databases through April 2016. The quality of the included studies was evaluated according to the 5.2 Cochrane Handbook standards, and CONSORT and STRICTA (Revised Standards for Reporting Interventions in Clinical Trials of Acupuncture) statements. Intervention. Interventions included conventional acupuncture treatment compared with no treatment, placebo, or conventional pharmaceutical medication. Major outcome measures were the alleviation of frequency and symptoms and the presence of hormone therapy–related side effects. Findings/Results. A total of 17 RCTs, including a total of 810 breast cancer patients were examined. The methodological quality of the trials was relatively rigorous in terms of randomization, blinding, and sources of bias. Compared with control therapies, the pooled results suggested that acupuncture had moderate effects in improving stiffness. No significant differences were observed in hot flashes, fatigue, pain, gastrointestinal symptoms, Kupperman index, general well-being, physical well-being, tumor necrosis factor (TNF), and interleukin (IL). Conclusions. Acupuncture therapy appears to be potentially useful in relieving functional stiffness. However, further large-sample trials with evidence-based design are still needed to confirm these findings.

Omega-3 fatty acid use for obese breast cancer patients with aromatase inhibitor-related arthralgia (SWOG S0927)

PURPOSE

Although aromatase inhibitors (AIs) prolong survival in post-menopausal breast cancer (BC) patients, AI-associated arthralgia can lead to discontinuation. Obese patients have higher rates of AI arthralgia than non-obese patients, but treatment options are limited. Omega-3 fatty acid (O3-FA) treatment for AI arthralgia has produced mixed results.

METHODS

We performed an exploratory analysis of SWOG S0927, a multicenter randomized placebo-controlled trial of O3-FA use for AI arthralgia. Post-menopausal women with stage I-III BC taking an AI were randomized to 24 weeks of O3-FAs or placebo. Brief Pain Inventory (BPI) questionnaires and fasting serum were collected at baseline, 12, and 24 weeks. The BPI assessment included worst pain, average pain, and pain interference scores (range 0-10).

RESULTS

Among the 249 participants, 139 had BMI < 30 kg/m² (56%) and 110 had BMI ≥ 30 kg/m² (44%). Among obese patients, O3-FA use was associated with significantly lower BPI worst pain scores at 24 weeks compared with placebo (4.36 vs. 5.70, p = 0.02), whereas among non-obese patients, there was no significant difference in scores between treatment arms (5.27 vs. 4.58, p = 0.28; interaction p = 0.05). Similarly, O3-FA use was associated with lower BPI average pain and pain interference scores at 24 weeks compared with placebo among obese patients, but no significant difference between treatment arms in non-obese patients (interaction p = 0.005 and p = 0.01, respectively).

CONCLUSIONS

In obese BC patients, O3-FA use was associated with significantly reduced AI arthralgia compared to placebo.

miR-1271 inhibits ERα expression and confers letrozole resistance in breast cancer

Attenuation of estrogen receptor α (ERα) expression via unknown mechanism(s) is a hallmark of endocrine-resistant breast cancer (BCa) progression. Here, we report that miR-1271 was significantly down-regulated in letrozole-resistant BCa tissues and in letrozole-resistant BCa cells. miR-1271 directly targeted the chromatin of DNA damage-inducible transcript 3 (DDIT3) gene. miR-1271 expression level was inversely correlated to DDIT3 mRNA level in BCa biopsies. Form a mechanistic standpoint, reintroduction of exogenous miR-1271 could effectively restore ERα level via inhibiting DDIT3 expression, thereby potentiating letrozole sensitivity in BCa cells. Moreover, DDIT3 deregulation promoted letrozole-resistance by acting as a potent corepressor of ESR1 transcription. Taken together, we have identified that disruption of the miR-1271/DDIT3/ERα cascade plays a causative role in the pathogenesis of letrozole resistance in BCa.

The association between pre-treatment occupational skill level and mood and symptom burden in early-stage, postmenopausal breast cancer survivors during the first year of anastrozole therapy

PURPOSE

Previous research has explored occupational activity of breast cancer survivors but has not examined the influence of occupational level on symptoms prospectively. The purpose of this study was to examine the relationship between occupational classification and changes in mood and symptom burden for postmenopausal breast cancer survivors during the first year of anastrozole therapy.

METHODS

This was an exploratory secondary analysis in 49 postmenopausal women receiving anastrozole therapy for early-stage breast cancer. Participants reported their occupation at baseline and completed self-report questionnaires measuring mood and symptom burden at baseline, 6 months, and 12 months. Occupation was classified according to four major skill levels delineated by the International Standard Classification of Occupations (ISCO).

RESULTS

Breast cancer survivors employed at occupational skill levels 1 through 3 reported significantly higher depressive symptoms, fatigue, and total symptoms on average than those employed at ISCO skill level 4. After adjusting for multiple comparisons, this pattern remained for the musculoskeletal, vasomotor, and gastrointestinal symptom subscales.

CONCLUSIONS

Breast cancer survivors employed at lower skill levels (i.e., ISCO 1-3) reported poorer mood and greater symptom burden than breast cancer survivors employed at a higher skill level (i.e., ISCO 4). Assessing baseline occupation of occupationally active breast cancer survivors may improve understanding of the association between types of occupations and mood and symptom trajectories and may inform development of interventions to mitigate symptom severity in order to help breast cancer survivors maintain optimal occupational function and adherence to therapy.

In vivo visualization of aromatase in animals and humans

Aromatase catalyzes the last and obligatory step in the biosynthesis of estrogens across species. In vivo visualization of aromatase can be performed using positron emission tomography (PET) with radiolabeled aromatase inhibitors such as [(11)C]vorozole. PET studies in rats, monkeys and healthy human subjects demonstrate widespread but heterogeneous aromatase availability in brain and body, which appears to be regulated in a species, sex and region-specific manner. Thus, aromatase availability is high in brain amygdala and in ovaries of all species examined to date, with males demonstrating higher levels than females in all comparable organs. However, the highest concentrations of aromatase in the human brain are found in specific nuclei of the thalamus while the highest levels in rats and monkeys are found in the amygdala. Regional brain aromatase availability is increased by androgens and inhibited by nicotine. Future studies may improve diagnosis and treatment in brain disorders and cancers overexpressing aromatase.

Aromatase overexpression in dysfunctional adipose tissue links obesity to postmenopausal breast cancer

The number of breast cancer cases has increased in the last a few decades and this is believed to be associated with the increased prevalence of obesity worldwide. The risk of breast cancer increases with age beyond menopause and the relationship between obesity and the risk of breast cancer in postmenopausal women is well established. The majority of postmenopausal breast cancers are estrogen receptor (ER) positive and estrogens produced in the adipose tissue promotes tumor formation. Obesity results in the secretion of inflammatory factors that stimulate the expression of the aromatase enzyme, which converts androgens into estrogens in the adipose tissue. Evidence demonstrating a link between obesity and breast cancer has led to the investigation of metabolic pathways as novel regulators of estrogen production, including pathways that can be targeted to inhibit aromatase specifically within the breast. This review aims to present some of the key findings in this regard.

Joint symptoms and health-related quality of life in postmenopausal women with breast cancer who completed 5 years of anastrozole

PURPOSE

To assess the joint symptoms and the impact on patients' health-related quality of life (HRQOL) due to 5 years of anastrozole from the baseline data in the N-SAS BC 05 trial, a randomized clinical trial was designed to assess the efficacy of 5 additional years of anastrozole among women with breast cancer.

METHODS

Joint symptoms and HRQOL were evaluated using an original questionnaire for joint symptoms, the Short Form 36-item Health Survey (SF-36), the EuroQol EQ-5D-3L, and a subscale of the Functional Assessment of Cancer Therapy-Endocrine Symptoms (FACT-ES).

RESULTS

Baseline joint symptom and HRQOL data were collected from 330 patients between November 2007 and March 2010. Joint pain and joint stiffness were reported by 61.6 and 59.1 % of patients, respectively, although these symptoms did not affect the activities of daily living in 96.0 and 97.9 % of patients, respectively. Joint pain was reported in the knee by 61.0 % of patients and in the hand by 36.0 % of patients. Joint stiffness mainly affected the hand (67.9 %), especially the proximal interphalangeal joint, and typically occurred upon waking up or in the morning. Most SF-36 domains had good average scores, although slight decreases in physical functioning and role-physical were observed (compared to the national standard scores). The mean EQ-5D utility score was 0.86, and the total FACT-ES subscale score was 62.2/76.

CONCLUSIONS

After 5 years of anastrozole, many of the patients reported joint pain and stiffness in mainly the hand and knee with mild symptoms and good HRQOL.

The effect of YOCAS©® yoga for musculoskeletal symptoms among breast cancer survivors on hormonal therapy

Up to 50% of breast cancer survivors on aromatase inhibitor therapy report musculoskeletal symptoms such as joint and muscle pain, significantly impacting treatment adherence and discontinuation rates. We conducted a secondary data analysis of a nationwide, multi-site, phase II/III randomized, controlled, clinical trial examining the efficacy of yoga for improving musculoskeletal symptoms among breast cancer survivors currently receiving hormone therapy (aromatase inhibitors [AI] or tamoxifen [TAM]). Breast cancer survivors currently receiving AI (N = 95) or TAM (N = 72) with no participation in yoga during the previous 3 months were randomized into 2 arms: (1) standard care monitoring and (2) standard care plus the 4-week yoga intervention (2x/week; 75 min/session) and included in this analysis. The yoga intervention utilized the UR Yoga for Cancer Survivors (YOCAS©(®)) program consisting of breathing exercises, 18 gentle Hatha and restorative yoga postures, and meditation. Musculoskeletal symptoms were assessed pre- and post-intervention. At baseline, AI users reported higher levels of general pain, muscle aches, and total physical discomfort than TAM users (all P ≤ 0.05). Among all breast cancer survivors on hormonal therapy, participants in the yoga group demonstrated greater reductions in musculoskeletal symptoms such as general pain, muscle aches and total physical discomfort from pre- to post-intervention than the control group (all P ≤ 0.05). The severity of musculoskeletal symptoms was higher for AI users compared to TAM users. Among breast cancer survivors on hormone therapy, the brief community-based YOCAS©® intervention significantly reduced general pain, muscle aches, and physical discomfort.

Steroidal and non-steroidal third-generation aromatase inhibitors induce pain-like symptoms via TRPA1

Use of aromatase inhibitors (AIs), exemestane, letrozole and anastrozole, for breast cancer therapy is associated with severe pain symptoms, the underlying mechanism of which is unknown. The electrophilic nature of AIs suggests that they may target the transient receptor potential ankyrin 1 (TRPA1) channel, a major pathway in pain transmission and neurogenic inflammation. AIs evoke TRPA1-mediated calcium response and current in rodent nociceptors and human cells expressing the recombinant channel. In mice, AIs produce acute nociception, which is exaggerated by pre-exposure to proalgesic stimuli, and, by releasing sensory neuropeptides, neurogenic inflammation in peripheral tissues. AIs also evoke mechanical allodynia and decreased grip strength, which do not undergo desensitization on prolonged AI administration. These effects are markedly attenuated by TRPA1 pharmacological blockade or in TRPA1-deficient mice. TRPA1 is a major mediator of the proinflammatory/proalgesic actions of AIs, thus suggesting TRPA1 antagonists for the treatment of pain symptoms associated with AI use.

Anti-tumor effect of Shu-Gan-Liang-Xue decoction in breast cancer is related to the inhibition of aromatase and steroid sulfatase expression

ETHNOPHARMACOLOGICAL RELEVANCE

Shu-Gan-Liang-Xue Decoction (SGLXD), a traditional Chinese herbal formula used to ameliorate the hot flushes in breast cancer patients, was reported to have anti-tumor effect on breast cancer. Estrogen plays a critical role in the genesis and evolution of breast cancer. Aromatase and steroid sulfatase (STS) are key estrogen synthesis enzymes that predominantly contribute to the high local hormone concentrations. The present study was to evaluate the anti-tumor effect of SGLXD on estrogen receptor (ER) positive breast cancer cell line ZR-75-1, and to investigate its underlying mechanisms both in vitro and in vivo.

MATERIALS AND METHODS

The anti-tumor activity of SGLXD in vitro was investigated using the MTT assay. The in vivo anti-tumor effect of SGLXD was evaluated in non-ovariectomized and ovariectomized athymic nude mice. The effect of SGLXD on enzymatic activity of aromatase and STS was examined using the dual-luciferase reporter (DLR) based on bioluminescent measurements. Aromatase and STS protein level were assessed using Western blot assay.

RESULTS

SGLXD showed dose-dependent inhibitory effect on the proliferation of ZR-75-1 cells with IC50 value of 3.40 mg/mL. It also suppressed the stimulating effect on cell proliferation of testosterone and estrogen sulfates (E1S). Oral administration of 6 g/kg of SGLXD for 25 days resulted in a reduction in tumor volume in non-ovariectomized and ovariectomized nude mice. The bioluminescent measurements confirmed that SGLXD has a dual-inhibitory effect on the activity of aromatase and STS. Western blot assay demonstrated that the treatment of SGLXD resulted in a decrease in aromatase and STS protein levels both in vitro and in vivo.

CONCLUSION

Our results suggested that SGLXD showed anti-tumor effect on breast cancer cells both in vitro and in vivo. The anti-tumor activity of SGLXD is related to inhibition of aromatase and STS via decreasing their expression. SGLXD may be considered as a novel treatment for ER positive breast cancer.

Impact of metabolizing enzymes on drug response of endocrine therapy in breast cancer

Estrogen-receptor positive breast cancer accounts for 75% of diagnosed breast cancers worldwide. There are currently two major options for adjuvant treatment: tamoxifen and aromatase inhibitors. Variability in metabolizing enzymes determines their pharmacokinetic profile, possibly affecting treatment response. Therefore, prediction of therapy outcome based on genotypes would enable a more personalized medicine approach, providing optimal therapy for each patient. In this review, the authors will discuss the current evidence on the most important metabolizing enzymes in endocrine therapy, with a special focus on CYP2D6 and its role in tamoxifen metabolism.

HIF-1α stimulates aromatase expression driven by prostaglandin E2 in breast adipose stroma

INTRODUCTION

The majority of postmenopausal breast cancers are estrogen-dependent. Tumor-derived factors, such as prostaglandin E2 (PGE2), stimulate CREB1 binding to cAMP response elements (CREs) on aromatase promoter II (PII), leading to the increased expression of aromatase and biosynthesis of estrogens within human breast adipose stromal cells (ASCs). Hypoxia inducible factor-1α (HIF-1α), a key mediator of cellular adaptation to low oxygen levels, is emerging as a novel prognostic marker in breast cancer. We have identified the presence of a consensus HIF-1α binding motif overlapping with the proximal CRE of aromatase PII. However, the regulation of aromatase expression by HIF-1α in breast cancer has not been characterized. This study aimed to characterize the role of HIF-1α in the activation of aromatase PII.

METHODS

HIF-1α expression and localization were examined in human breast ASCs using quantitative PCR (QPCR), Western blotting, immunofluorescence and high content screening. QPCR and tritiated water-release assays were performed to assess the effect of HIF-1α on aromatase expression and activity. Reporter assays and chromatin immunoprecipitation (ChIP) were performed to assess the effect of HIF-1α on PII activity and binding. Treatments included PGE2 or DMOG ((dimethyloxalglycine), HIF-1α stabilizer). Double immunohistochemistry for HIF-1α and aromatase was performed on tissues obtained from breast cancer and cancer-free patients.

RESULTS

Results indicate that PGE2 increases HIF-1α transcript and protein expression, nuclear localization and binding to aromatase PII in human breast ASCs. Results also demonstrate that HIF-1α significantly increases PII activity, and aromatase transcript expression and activity, in the presence of DMOG and/or PGE2, and that HIF-1α and CREB1 act co-operatively on PII. There is a significant increase in HIF-1α positive ASCs in breast cancer patients compared to cancer-free women, and a positive association between HIF-1α and aromatase expression.

CONCLUSIONS

This study is the first to identify HIF-1α as a modulator of PII-driven aromatase expression in human breast tumor-associated stroma and provides a novel mechanism for estrogen regulation in obesity-related, post-menopausal breast cancer. Together with our on-going studies on the role of AMP-activated protein kinase (AMPK) in the regulation of breast aromatase, this work provides another link between disregulated metabolism and breast cancer.

Patient-reported discontinuation of endocrine therapy and related adverse effects among women with early-stage breast cancer

BACKGROUND

Approximately 20% to 50% of women diagnosed with hormone receptor-positive breast cancer discontinue endocrine therapy early; most reports come from automated pharmacy data or small self-report evaluations. We conducted a larger self-report evaluation of endocrine therapy discontinuation associated with patient characteristics and therapy-related adverse effects.

METHODS

We surveyed 538 women from a single health plan who were diagnosed with early-stage breast cancer from 2002 to 2008 and received endocrine therapy. Women reported adverse effects and reasons for discontinuation via mailed survey; tumor characteristics were obtained via registry linkage. We classified women as discontinuers if they self-reported stopping therapy and their self-reported duration of tamoxifen plus aromatase inhibitor (AI) use was < 5 years, and nondiscontinuers if they self-reported ≥ 5 years use or current use. We estimated odds ratios (ORs) with 95% CIs for discontinuation versus continuation by using logistic regression adjusted for age and year of diagnosis.

RESULTS

Among 538 women, 98 (18.2%) discontinued endocrine therapy early. Women with positive lymph nodes (v negative) were significantly less likely to discontinue therapy (odds ratio [OR] = 0.54; 95% CI, 0.31 to 0.93). Almost all women (94%) experienced adverse effects. Experiencing headaches was associated with discontinuation of AIs (OR = 4.16; 95% CI, 2.16 to 8.01) and tamoxifen (OR = 2.34; 95% CI, 1.24 to 4.41); few other individual adverse effects were related to discontinuation despite most discontinuers reporting they "did not like adverse effects" (AIs: 66.7%, tamoxifen: 59.1%).

CONCLUSION

Few individual adverse effects or patient characteristics were significantly associated with endocrine therapy discontinuation, yet adverse effects were prevalent and were the most common reason women reported for discontinuing therapy.

A humanized pattern of aromatase expression is associated with mammary hyperplasia in mice

Aromatase is essential for estrogen production and is the target of aromatase inhibitors, the most effective endocrine treatment for postmenopausal breast cancer. Peripheral tissues in women, including the breast, express aromatase via alternative promoters. Female mice lack the promoters that drive aromatase expression in peripheral tissues; thus, we generated a transgenic humanized aromatase (Arom(hum)) mouse line containing a single copy of the human aromatase gene to study the link between aromatase expression in mammary adipose tissue and breast pathology. Arom(hum) mice expressed human aromatase, driven by the proximal human promoters II and I.3 and the distal promoter I.4, in breast adipose fibroblasts and myoepithelial cells. Estrogen levels in the breast tissue of Arom(hum) mice were higher than in wild-type mice, whereas circulating levels were similar. Arom(hum) mice exhibited accelerated mammary duct elongation at puberty and an increased incidence of lobuloalveolar breast hyperplasia associated with increased signal transducer and activator of transcription-5 phosphorylation at 24 and 64 wk. Hyperplastic epithelial cells showed remarkably increased proliferative activity. Thus, we demonstrated that the human aromatase gene can be expressed via its native promoters in a wide variety of mouse tissues and in a distribution pattern nearly identical to that of humans. Locally increased tissue levels, but not circulating levels, of estrogen appeared to exert hyperplastic effects on the mammary gland. This novel mouse model will be valuable for developing tissue-specific aromatase inhibition strategies.

Pharmacogenomics of third-generation aromatase inhibitors

INTRODUCTION

Breast cancer is a common, life-threatening disease among women. Contemporary hormonal therapy with third-generation aromatase inhibitors for estrogen-receptor-positive breast cancers in postmenopausal women is still facing the challenge of interpatient variability in therapeutic response and intensity of adverse effects.

AREAS COVERED

This review highlights up-to-date literature regarding genomic findings in the literature pertaining to anastrozole, exemestane and letrozole metabolism, as well as the drug target aromatase. Genetic polymorphisms in phase I and II aromatase inhibitor metabolizing enzymes that contribute to altered responses among different patient genotypes are discussed. Similarly, aromatase CYP19A1 functional genetic polymorphisms are presented in correlation to altered aromatase activity, disease prognosis and severity of aromatase inhibitor adverse effects.

EXPERT OPINION

The field of pharmacogenomics has shown remarkable progress over the last few years, notably in cancer. However, large comprehensive genotyping studies, evaluated under clinical settings, are still needed to unravel the potential impact of aromatase inhibitor pharmacogenomics on breast cancer treatment, monitoring and predicting adverse effects.

Approval summary: letrozole (Femara® tablets) for adjuvant and extended adjuvant postmenopausal breast cancer treatment: conversion of accelerated to full approval

On April 30, 2010, the U.S. Food and Drug Administration converted letrozole (Femara®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor-positive early breast cancer. The initial accelerated approvals of letrozole for adjuvant and extended adjuvant treatment on December 28, 2005 and October 29, 2004, respectively, were based on an analysis of the disease-free survival (DFS) outcome of patients followed for medians of 26 months and 28 months, respectively. Both trials were double-blind, multicenter studies. Both trials were unblinded early when an interim analysis showed a favorable letrozole effect on DFS. In updated intention-to-treat analyses of both trials, the risk for a DFS event was lower with letrozole than with tamoxifen (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.77-0.99; p = .03) in the adjuvant trial and was lower than with placebo (HR, 0.89; 95% CI, 0.76-1.03; p = .12) in the extended adjuvant trial. The latter analysis ignores the interim switch of 60% of placebo-treated patients to letrozole. Bone fractures and osteoporosis were reported more frequently following treatment with letrozole whereas tamoxifen was associated with a higher risk for endometrial proliferation and endometrial cancer. Myocardial infarction was more frequently reported with letrozole than with tamoxifen, but the incidence of thromboembolic events was higher with tamoxifen than with letrozole. Lipid-lowering medications were required for 25% of patients on letrozole and 16% of patients on tamoxifen.

Drug switch because of treatment-related adverse side effects in endocrine adjuvant breast cancer therapy: how often and how often does it work?

Therapy-related adverse side effects are a main reason for non-persistence to adjuvant endocrine breast cancer therapy. This study reports frequency of drug-related adverse side effects that were so severe that a modification of the therapy was necessary. We evaluated how many patients discontinued adjuvant endocrine therapy because of these side effects (non-persistence). Last, we analyzed how often a drug switch was undertaken for this reason and how often this measure led to the patient successfully continuing their endocrine therapy. Data concerning all postmenopausal breast cancer patients (≤ 80 years), who initiated endocrine adjuvant therapy between 1998 and 2008 in a Swiss breast center (n = 400), were analyzed. Out of these 400 women, 37 (9.3%) were defined as being non-persistent to the therapy; out of these, 24 (64.9%) because of therapy-related side effects. About 78 patients (19.5%) suffered from severe therapy-related side effects that made a modification of therapy necessary. Out of these 78 cases, 14 patients (17.9%) stopped the therapy without attempting a drug switch (non-persistence). In 64 patients (82.1%; 16% of all women who started endocrine therapy), a drug switch was undertaken. Out of these 64 cases, in 52 cases (81.3%) endocrine therapy was completed after therapy modification. Patients who reported one major adverse effect were more likely to continue the endocrine therapy after a drug switch (P = 0.048) compared with those who suffered from at least two different side effects. In 10 of the 64 cases (15.6%), modification of the therapy was not successful and the patients stopped the treatment prematurely (non-persistence) because of ongoing side effects. In cases when therapy-related side effects occur, a drug switch is a promising step to further improve persistence and, by doing so, the outcome of breast cancer patients.

Relationship between severity of symptoms and quality of life in patients with breast cancer receiving adjuvant hormonal therapy

PURPOSE/OBJECTIVES

To describe symptoms and quality of life (QOL) of patients with breast cancer receiving adjuvant hormonal therapy and to examine possible relationships between the two measurements.

DESIGN

Descriptive, correlational study.

SETTING

An oncology clinic within a tertiary medical center in Israel.

SAMPLE

Convenience sample of 132 patients diagnosed with primary breast cancer receiving hormonal therapy.

METHODS

Data collection was conducted through the self-administered Functional Assessment of Cancer Therapy endocrine subscale and a sociodemographic and medical information questionnaire.

MAIN RESEARCH VARIABLES

QOL and symptoms of hormonal therapy.

FINDINGS

Ten symptoms were categorized by more than 20% of the participants as "very much" or "quite a bit." The mean QOL score for the participants was higher than that for a healthy population, although a correlation was found between fewer symptoms and higher QOL. Mood swings and irritability were the symptoms most strongly associated with a decrease in QOL. Patients who exercised had higher QOL scores.

CONCLUSIONS

Adjuvant hormonal therapy did not affect the QOL of a majority of patients with primary breast cancer. A reduced number of symptoms indicated a higher QOL. Mood swings and irritability have a negative impact on QOL.

IMPLICATIONS FOR NURSING

A need exists to design a program to follow up on hormonal symptoms and the QOL of patients receiving hormonal therapy and to encourage patients to engage in regular exercise.

Vitamin D receptor and enzyme expression in dorsal root ganglia of adult female rats: modulation by ovarian hormones

Vitamin D insufficiency impacts sensory processes including pain and proprioception, but little is known regarding vitamin D signaling in adult sensory neurons. We analyzed female rat dorsal root ganglia (DRG) for vitamin receptor (VDR) and the vitamin D metabolizing enzymes CYP27B1 and CYP24. Western blots and immunofluorescence revealed the presence of these proteins in sensory neurons. Nuclear VDR immunoreactivity was present within nearly all neurons, while cytoplasmic VDR was found preferentially in unmyelinated calcitonin gene-related peptide (CGRP)-positive neurons, colocalizing with CYP27B1 and CYP24. These data suggest that 1,25(OH)(2)D3 may affect sensory neurons through nuclear or extranuclear signaling pathways. In addition, local vitamin D metabolite concentrations in unmyelinated sensory neurons may be controlled through expression of CYP27B1 and CYP24. Because vitamin D deficiency appears to exacerbate some peri-menopausal pain syndromes, we assessed the effect of ovariectomy on vitamin D-related proteins. Two weeks following ovariectomy, total VDR expression in DRG dropped significantly, owing to a slight decrease in the percentage of total neurons expressing nuclear VDR and a large drop in unmyelinated CGRP-positive neurons expressing cytoplasmic VDR. Total CYP27B1 expression dropped significantly, predominantly due to decreased expression within unmyelinated CGRP-positive neurons. CYP24 expression remained unchanged. Therefore, unmyelinated CGRP-positive neurons appear to have a distinct vitamin D phenotype with hormonally-regulated ligand and receptor levels. These findings imply that vitamin D signaling may play a specialized role in a neural cell population that is primarily nociceptive.

Letrozole: a review of its use in the treatment of postmenopausal women with hormone-responsive early breast cancer

Letrozole (Femara) is a third-generation, nonsteroidal aromatase inhibitor. Adjuvant therapy with letrozole is more effective than tamoxifen in postmenopausal women with hormone-responsive early breast cancer, and extended adjuvant therapy with letrozole after the completion of adjuvant tamoxifen therapy is more effective than placebo in this patient population; letrozole is generally well tolerated. Ongoing trials will help answer outstanding questions regarding the optimal duration of letrozole therapy in early breast cancer and its efficacy compared with other third-generation aromatase inhibitors such as anastrozole. In the meantime, letrozole should be considered a valuable option in the treatment of postmenopausal women with hormone-responsive early breast cancer, both as adjuvant and extended adjuvant therapy.

Increased intrafollicular androgen levels affect human granulosa cell secretion of anti-müllerian hormone and inhibin-B

OBJECTIVE

To evaluate whether the follicular fluid concentrations of anti-müllerian hormone (AMH), inhibin-B, and P become affected by androgen priming before controlled ovarian hyperstimulation and IVF/intracytoplasmic sperm injection (ICSI) treatment, extending our previous study.

DESIGN

Prospective nonrandomized clinical study.

SETTING

University hospital.

PATIENT(S)

Patients (N = 45) undergoing IVF/ICSI treatment received androgen priming before controlled ovarian hyperstimulation.

INTERVENTION(S)

All patients received cetrorelix, 3 mg SC, on cycle day 2 and 5. Group I (n = 15) received no other pretreatment. Group II (n = 15) received 2.5 mg once daily of letrozole from cycle day 2 through 8. Group III (n = 15) received letrozole as group II plus 1,250 IU hCG on cycle day 2.

MAIN OUTCOME MEASURE(S)

Follicular fluid concentrations of AMH, inhibin-B, and steroids.

RESULT(S)

Follicular fluid concentrations of AMH were significantly higher in group III than in groups I and II (2.6 +/- 0.3 vs. 1.6 +/- 0.2 and 1.5 +/- 0.4 ng/mL. Concentrations of inhibin-B were significantly lower in group II and III as compared with group I (27 +/- 4, 27 +/- 3 versus 46 +/- 6 ng/mL, respectively). Follicular fluid P concentrations remained similar in all groups.

CONCLUSION(S)

Granulosa cell production of AMH was significantly augmented and inhibin-B production was significantly reduced by a highly specific pharmacologically induced increase in the intrafollicular androgen levels, suggesting a dual action of androgen on follicular growth and development.

Treatment of breast cancer in older women

BACKGROUND

Breast carcinoma management in the elderly often differs from the management in younger women and there is considerable controversy about what constitutes appropriate cancer care for older women. This controversy is reflected in the persistence of age-dependent variations in care over time, with older women being less likely to receive definitive care for breast cancer. There has been a significant increase in the last years in the number of studies conducted in older patients with breast cancer. Although available age-specific clinical trials data demonstrate that treatment efficacy is not modified by age, this evidence is limited by the lack of inclusion of substantial numbers of older women, particularly those of advanced age and those with comorbidities.

METHOD

The literature-based evidence of the last 10 years was extensively reviewed on the main issues concerning the treatment of breast cancer in older women.

RESULTS

Surgical treatment in older patients has evolved from avoidance to mastectomy to breast-conserving surgery, similarly to younger patients. Given its negative effect on the quality of life, in the last few years the role of adjuvant radiotherapy has been questioned in elderly patients with breast cancer. Adjuvant chemotherapy benefit in older patients applies mainly to Estrogen-receptor-negative patients, while in Estrogen-receptor-positive patients a major role is played by endocrine treatment. New "elderly-friendly" drugs, that can help clinicians to reduce toxicity, are now available for breast cancer.

Aromatase inhibitor-induced arthralgia: clinical experience and treatment recommendations

It is well documented that the aromatase inhibitors (AIs) are superior to tamoxifen as adjuvant endocrine therapy in postmenopausal women with hormone receptor-positive breast cancer. However, compared with tamoxifen, an elevated incidence of arthralgia has been observed during AI treatment. Concerns have been raised that AI-induced arthralgia may dissuade patients from completing their full AI treatment course, and may also deter physicians from prescribing an AI if they feel that patients may be at risk of permanent joint damage. Patient education about the possibility of experiencing arthralgia, and effective management of symptoms if they appear, are important in helping patients adhere to AI treatment, and consequently improving breast cancer outcomes. In this paper, we discuss the potential mechanisms behind AI-induced arthralgia, review the frequency with which arthralgia occurs, and propose for the first time an algorithm specifically for the treatment of AI-induced arthralgia. As with joint pain in non-breast cancer patients, a sequential approach to disease management is recommended, involving modifying the patient's lifestyle in addition to taking a stratified approach to pharmacological intervention with analgesia and anti-inflammatory medication. Knowing that joint symptoms can be managed in most patients may encourage patient-physician communication and treatment compliance.

The use of third-generation aromatase inhibitors and tamoxifen in the adjuvant treatment of postmenopausal patients with hormone-dependent breast cancer: evidence based review

(1) Worldwide, breast cancer is the most common type of cancer in women, and the second most frequently diagnosed cancer overall.(2) Since its approval approximately 20 years ago, a 5-year course of tamoxifen has been the standard adjuvant therapy for patients with hormone-dependent breast cancer.(3) Recently, data from large randomised clinical trials have indicated that the third-generation aromatase inhibitors (letrozole, anastrozole and exemestane) are more effective than tamoxifen as adjuvant therapy in postmenopausal women with operable breast cancer when given either initially, or sequentially following initial tamoxifen therapy, within the first five years post-operatively.(4) One large randomised trial demonstrated that administration of letrozole to high-risk (node-positive) postmenopausal patients who have completed 5 years' adjuvant tamoxifen further prevents late recurrences and contralateral breast cancer, contrary to the lack of obvious benefit of extending tamoxifen treatment to 10 years found in another large randomised study.(5) Aromatase inhibitors and tamoxifen should not be administered concomitantly as this does not provide additional benefit, and a large, randomised study demonstrated reduced disease-free survival with the combination of anastrozole plus tamoxifen compared with anastrozole alone.(6) Further studies are required to establish whether the third-generation aromatase inhibitors prolong overall survival compared with tamoxifen, to evaluate their long-term efficacy and tolerability profiles, and to determine the optimal treatment duration with these agents.

Involvement of maternal embryonic leucine zipper kinase (MELK) in mammary carcinogenesis through interaction with Bcl-G, a pro-apoptotic member of the Bcl-2 family

Introduction

Cancer therapies directed at specific molecular targets in signaling pathways of cancer cells, such as tamoxifen, aromatase inhibitors and trastuzumab, have proven useful for treatment of advanced breast cancers. However, increased risk of endometrial cancer with long-term tamoxifen administration and of bone fracture due to osteoporosis in postmenopausal women undergoing aromatase inhibitor therapy are recognized side effects. These side effects as well as drug resistance make it necessary to search for novel molecular targets for drugs on the basis of well-characterized mechanisms of action.

Methods

Using accurate genome-wide expression profiles of breast cancers, we found maternal embryonic leucine-zipper kinase (MELK) to be significantly overexpressed in the great majority of breast cancer cells. To assess whether MELK has a role in mammary carcinogenesis, we knocked down the expression of endogenous MELK in breast cancer cell lines using mammalian vector-based RNA interference. Furthermore, we identified a long isoform of Bcl-G (Bcl-G_L), a pro-apoptotic member of the Bcl-2 family, as a possible substrate for MELK by pull-down assay with recombinant wild-type and kinase-dead MELK. Finally, we performed TUNEL assays and FACS analysis, measuring proportions of apoptotic cells, to investigate whether MELK is involved in the apoptosis cascade through the Bcl-G_L-related pathway.

Results

Northern blot analyses on multiple human tissues and cancer cell lines demonstrated that MELK was overexpressed at a significantly high level in a great majority of breast cancers and cell lines, but was not expressed in normal vital organs (heart, liver, lung and kidney). Suppression of MELK expression by small interfering RNA significantly inhibited growth of human breast cancer cells. We also found that MELK physically interacted with Bcl-G_L through its amino-terminal region. Immunocomplex kinase assay showed that Bcl-G_L was specifically phosphorylated by MELK in vitro. TUNEL assays and FACS analysis revealed that overexpression of wild-type MELK suppressed Bcl-G_L-induced apoptosis, while that of D150A-MELK did not.

Conclusion

Our findings suggest that the kinase activity of MELK is likely to affect mammary carcinogenesis through inhibition of the pro-apoptotic function of Bcl-G_L. The kinase activity of MELK could be a promising molecular target for development of therapy for patients with breast cancers.