Burcu Cakar

Targeted Therapy for Breast Cancer

Breast cancer is a heterogeneous group of diseases that are clinically subdivided as hormone receptor-positive, human epidermal growth factor receptor 2-positive (HER2(+)), and triple-negative breast cancer, to guide therapeutic interventions. Agents that target estrogen receptor (ER) and HER2 are among the most successful cancer therapeutics. However, de novo or acquired resistance is common, despite the development of newer agents against these pathways. As our understanding of tumor biology improves, novel targets are being identified. Notably, inhibitors against several pathways [including, among others, the phosphoinositide 3-kinase/mammalian target of rapamycin (PI3K/mTOR), cell-cycle regulation, heat shock protein, and epigenetic pathways] have demonstrated promising activity in clinical trials, and the mTOR-inhibitor everolimus has been approved for advanced or metastatic aromatase inhibitor-resistant ER(+) breast cancer. At present, there are no established targeted agents for triple-negative breast cancer (negative ER, progesterone receptor, and HER2). Although poly(ADP-ribose) polymerase inhibitors have shown promising activity in BRCA-related cancers, its value in the treatment of triple-negative breast cancers remains to be demonstrated. In this Review, we present a basic understanding of the major targeted agents in current practice and under development for the treatment of breast cancer in the context of the three clinical subgroups.

Pretreatment with AT-101 enhances tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis of breast cancer cells by inducing death receptors 4 and 5 protein levels

PurposeTumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a member of the TNF superfamily and has been shown to induce extrinsic pathway of apoptosis in many types of cancer cells. AT-101, an (−)-enantiomer of gossypol, is a potent anticancer agent that is shown to be an inhibitor of Bcl-2/Bcl-XL. In this study, we searched whether pretreatment with either of these drugs would result in the enhancement of apoptosis through induction of death receptors and activation of mitochondrial pathways within breast cancer cells.MethodsHuman breast cancer (MCF-7 and MDA-MB-231) and normal breast cells (MCF-10A) were treated with drugs alone/in combination/sequentially. XTT cell viability assay was used to evaluate cytotoxicity. For showing apoptosis, both DNA Fragmentation and caspase 3/7 activity measurements were done. ELISA and Western blot analysis were done to assess DR4 and DR5 protein levels. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array.ResultsThe sequential treatment of AT-101 followed by TRAIL resulted in significant synergistic cytotoxicity and apoptosis. Moreover, pretreatment of breast cancer cells with AT-101 and then with TRAIL caused enhancement of the expression levels of DR4 and DR5 in both cancer cell lines, suggesting that these cells were under strong apoptotic stimuli.ConclusionsThese findings all together, strongly suggest that pretreatment with AT-101 enhances TRAIL-induced death-inducing signaling complex resulting in the engagement of the mitochondrial pathway to apoptosis in breast cancer cells. These promising, preliminary results make AT-101 and TRAIL a novel combination treatment candidate for breast cancer.

Enhancing cytotoxic and apoptotic effect in OVCAR-3 and MDAH-2774 cells with all-trans retinoic acid and zoledronic acid: a paradigm of synergistic molecular targeting treatment for ovarian cancer

BackgroundOvarian cancer is the most fatal gynecologic malignancies in the world. Although, platinum based treatments are widely used, the disease becomes treatment refractory within two years, and novel treatment options should be searched. All- trans retinoic acid (ATRA) induces growth arrest, differentiation and cell death in some types of cancer cells and its combination with various anticancer agents results in enhanced cytotoxicity. Zoledronic acid is a common bisphosphonate known for its anticancer effects beyond its current use in the treatment of cancer-induced bone disease. We aimed to investigate the possible additive/synergistic effect of both agents in OVCAR-3 and MDAH-2774 ovarian cancer cell lines, since both agents show superiority to conventional cytotoxics in terms of adverse events.MethodsXTT cell proliferation assay was used for showing cytotoxicity. For verifying apoptosis, both DNA Fragmentation by ELISA assay and caspase 3/7 activity measurement were used. OligoGeArray® which consists of 112 apoptosis related genes was used to elucidate the genetic changes within cancer cells. To validate our oligoarray results, quantitative real-time PCR was performed on four selected genes that were maximally effected by the combination treatment: lymphotoxin beta receptor (LTBR), myeloid cell leukemia-1 (MCL-1), tumor necrosis factor receptor superfamily, member 1A (TNFRSF1A), TNFRSF1A-associated death domain protein (TRADD).ResultsWe demonstrated that a novel combination of ATRA and zoledronic acid is a strong inducer of apoptotic related cell death in both ovarian cancer cells. While the combination therapy significantly induced proapoptotic genes such as tumor necrosis factor receptor superfamily (TNFRSF), TRADD and caspase 4, some of the antiapoptotic genes such as members of MCL-1, LTBR, BAG3 and Bcl-2 family members were inhibited.ConclusionsThese are the preliminary molecular results of a novel combination treatment of ATRA and zoledronic acid, with fewer side effects as compared to conventional cytotoxic agents. With additional experimental analysis, it may serve as a good option for the treatment of refractory and elderly ovarian cancer patients, for whom there exists very limited choice of treatment.

Adjuvant chemotherapy may contribute to an increased risk for metabolic syndrome in patients with breast cancer

Purpose Cytotoxic treatment may cause weight gain and important alterations in the metabolic status of breast cancer (BC) patients. The aim of this study was to investigate the changes in metabolic and anthropometric parameters of patients with BC who received adjuvant chemotherapy. Methods All consecutive women treated with adjuvant TAC (docetaxel 75 mg/m2, doxorubicine 50 mg/m2, cyclophosphamide 500 mg/m2) chemotherapy for node-positive breast carcinoma at our Institution between 2008 and 2010 were included. Results Among 104 patients, 84 of them were stage II and 20 of them were stage III. When we compared the measurements between 1st and 6th adjuvant chemotherapy, we observed statistically significant increases in weight and serum triglyceride levels, and decreases in high density lipoprotein, apolipoprotein A-1, transferrin, albumin and prealbumin levels. An elevation of follicle stimulating hormone, luteinizing hormone together with the decrease of estradiol was detected. Waist-to-hip ratio has also increased significantly. In subgroup analyses, we observed dramatic changes in body mass index in pre-menopausal women whereas no significant change was seen in the post-menopausal group. Conclusions Adjuvant chemotherapy may contribute to an increased risk for metabolic syndrome in patients with BC and these changes are more profound in pre-menopausal patients.

The Role of Body Mass Index in Triple Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) has none of the targeted treatment choices due to its distinct biological property, making this subtype a unique disease. In this study, we evaluated the impact of obesity on clinical outcomes of TNBC. Methods: The data of breast cancer patients admitted to our department were collected. TNBC was defined as lack of estrogen receptor (ER), progesterone receptor (PR) and HER-2. The body mass index (BMI) of 112 TNBC patients was calculated with weight at the time of diagnosis and height. The patients were classified into groups with a BMI of < 25 (normal/underweight), 25-29.9 (overweight) or ≥ 30 (obese). After a mean follow-up of 23.2 ± 15.5 months, there were 12 recurrences (10.71%) and 6 deaths (5.35%). Disease-free survival (DFS) and overall survival (OS) were assessed. Results: The survival analyses of all the patients did not demonstrate any differences in OS or DFS in obese as compared to non-obese patients. However, we showed that obesity was associated with a poorer OS for postmenopausal TNBC patients (p < 0.05). Conclusion: Obesity is related to a poorer OS in postmenopausal TNBC patients. Due to the heterogeneous disease profile of TNBC, larger randomized studies will be needed to clarify the exact role of obesity in TNBC.

Comparing time to disease progression of irinotecan and oxaliplatin-based chemotherapies in colorectal cancer patients with liver only metastasis.

Objectives: The liver is the most common metastatic site in colorectal cancer (CRC). In this study, we evaluated if there is any difference between first-line irinotecan-based and oxaliplatin-based chemotherapies in the duration of time to disease progression (TTP) in CRC patients with only liver metastasis. Methods: We retrospectively reviewed the medical records of patients with metastatic CRC referred to the Medical Oncology Department at the Faculty of Medicine of Ege University, between January 2002 and December 2010. Seventy-seven patients had only liver metastasis and completed their first-line chemotherapy. Forty-two patients had oxaliplatin-based treatments while 12 also had bevacizumab therapy, and 35 patients had irinotecan-based treatments while 16 also had bevacizumab therapy. Results: Median TTP was 6.70±0.29 months for patients treated with oxaliplatin+5-fluorouracil (5-FU) and 8.33±1.15 months for patients treated with oxaliplatin+5-FU+bevacizumab. TTP was significantly improved for patients who received irinotecan+5-FU+bevacizumab (median TTP, 13.73±2.10 mo) when compared with irinotecan+5-FU (median TTP, 5.13±0.70 mo). Conclusions: Although previous studies showed no survival difference between these 2 chemotherapeutic agents in metastatic CRC, there might be differences in the benefit of delaying the disease progression in subgroup populations. Irinotecan+5-FU with bevacizumab combination chemotherapy may be superior in the first-line treatment of CRC with hepatic only metastasis.

The Impact of Subtype Distribution in Inflammatory Breast Cancer Outcome

Objective Inflammatory breast cancer (IBC) has an unfavourable prognosis despite the advances made in the treatment of breast cancer. Our study aimed to define immunohistochemistry-based surrogate subtype distribution to determine whether the breast cancer subtype accompanied survival outcome differences in IBC. Materials and Methods Medical records of female breast cancer patients with non-metastatic inflammatory breast cancer admitted to our clinic between March 2000 and December 2015 were retrospectively reviewed. Patient demographics, clinical and pathological feature of the primary tumour, adjuvant treatment options and survival data were analysed. Intrinsic breast cancer subtypes were defined according to ER, PR, HER-2 and ki-67 status. Results We identified 129 non-metastatic inflammatory breast cancer patients. Median follow-up was 73 months. 10 (7.7%) were luminal A-like, 67 (51.9%) were luminal B-like, 37 (28.6%) were HER-2 positive, and 15 (11.6%) were triple negative (TNBC) by immunohistochemistry. There were no statistically significant differences between subtypes in terms of histological type, grade, tumour size and lymph node status. Median disease-free survival was 47 months (95% confidence interval [CI] 29.2-82.6) and median overall survival was 75 months (95% CI 64.7-90.8). Triple negative breast cancer showed poorer outcome than other subgroups. Presence of TNBC disease was associated with poorer outcome compared to luminal A (HR: 0.19, 95% CI 0.04-0.92, p: 0.039), luminal B (HR: 0.34, 95% CI 0.15-0.74, p: 0.007) and HER-2 positive subgroups (HR: 0.40, 95% CI 0.17-0.94, p:0.037). Luminal A patients had a trend to have a better overall survival which did not reach to a statistical significant difference. Conclusion Our study put forth that IBC have a poor prognosis irrespective of breast cancer surrogate subtype distribution. Luminal A, the most frequent subtype of breast cancer was the least common in our IBC patient group. TNBC had the worst outcome when compared to other breast cancer subtypes.

Tyrosine Kinase Inhibitors

Breast cancer is the most common cancer in women worldwide. Although various subgroups are defined according to the expression of hormones and ErbB family receptors, it is well known that this disease is more heterogeneous than its classification system suggests. As new effective therapeutic choices are developed and used clinically, resistance to these new agents is also being observed. The most promising new anti-HER therapies are T-DM1 and pertuzumab, which has been evaluated in trastuzumab-resistant patients and also in a first-line setting with trastuzumab. The dual blockage of HER seems to be a favorable approach for these patients; however, the downstream signaling steps can be activated to overcome the tyrosine kinase inhibition. Because tumor cells can adapt themselves by using alternative pathways to maintain proliferation, providing a sufficient treatment approach also requires the consideration of possible escape mechanisms in tumor cells. By inhibiting tyrosine kinases combined with another agent that affects downstream factors of the PI3K/AKT/mTOR pathway, drug resistance in breast cancer can be overcome or delayed. In this chapter, we discuss the new tyrosine kinase inhibitors that inhibit more than only HER-2 and discuss some ongoing clinical trials in this area. In so doing, we hope to provide information for overcoming tyrosine kinase drug resistance and to identify the ideal settings for these treatment choices according to recent data.

Reply To the Editor, Re: Bicakli et al. Adjuvant chemotherapy may contribute to an increased risk for metabolic syndrome in patients with breast cancer. J Oncol Pharm Pract, published online September 2014. DOI: 10.1177/1078155214551315

We thank Agilli et al. for their interest in our article and their comments on prealbumin. Agilli et al. emphasized the importance of the differential effects on prealbumin and acknowledged that certain accompanying conditions and medications may influence our results. They mentioned that certain diseases especially the chronic ones such as chronic liver diseases, chronic kidney disease, etc. may affect serum prealbumin levels. However, all the participants in our study had adjuvant chemotherapy, and this means that they did not have these mentioned chronic diseases. Because, if they had, they could not be treated with such toxic chemotherapeutics in the adjuvant setting. Besides, 81.7% of the patients had no comorbid diseases as we had defined both in the manuscript text and in Table 1. The remainder had various chronic diseases such as diabetes mellitus (6.7%), hypertension (8.7%), gastric ulcer (1.9%), and osteoporosis (1%). In addition, our inclusion criteria were Eastern Cooperative Oncology Group performance status <2 and adequate organ function, and we excluded the patients with morbid obesity (body mass index >40 kg/m) and a known family history of dyslipidemia. In our study, none of the patients received hormone replacement therapy including estrogens and progestational agents and any anabolic steroids. Our patients were early stage breast cancer patients with good performance status, and therefore, no dietary food supplements and vitamins were prescribed to them. Additionally, in literature search, we could not find any interactions between serum prealbumin levels and various drugs in patients with malignant diseases. Studies concerning prealbumin and malignancy were all investigating the role of prealbumin as a biomarker for predicting nutritional status of the patients or cancer diagnosis. So, despite its interactions, prealbumin can be one of the indicators of nutritional status and is indicated especially as a biochemical nutritional parameter used in the monitoring of nutrition applications in ESPEN guidelines. In order to measure serum hormonal (estradiol, follicle stimulating hormone, luteinizing hormone, free T3 and T4, thyroid stimulating hormone) and metabolic parameters related with metabolic syndrome (serum glucose, triglyceride, total cholesterol, highdensity lipoprotein, low-density lipoprotein, apolipoprotein A-1, lipoprotein A-1) and nutritional status (transferrin, albumin, prealbumin), blood samples were analyzed in fasting state. Blood samples for measuring serum proteins were taken in the sitting position as these patients were evaluated in outpatient clinic.