Brittany A. Simone

Caloric restriction augments radiation efficacy in breast cancer

Dietary modification such as caloric restriction (CR) has been shown to decrease tumor initiation and progression. We sought to determine if nutrient restriction could be used as a novel therapeutic intervention to enhance cytotoxic therapies such as radiation (IR) and alter the molecular profile of triple-negative breast cancer (TNBC), which displays a poor prognosis. In two murine models of TNBC, significant tumor regression is noted with IR or diet modification, and a greater regression is observed combining diet modification with IR. Two methods of diet modification were compared, and it was found that a daily 30% reduction in total calories provided more significant tumor regression than alternate day feeding. At the molecular level, tumors treated with CR and IR showed less proliferation and more apoptosis. cDNA array analysis demonstrated the IGF-1R pathway plays a key role in achieving this physiologic response, and multiple members of the IGF-1R pathway including IGF-1R, IRS, PIK3ca and mTOR were found to be downregulated. The innovative use of CR as a novel therapeutic option has the potential to change the biology of tumors and enhance the opportunity for clinical benefit in the treatment of patients with TNBC.

Selectively starving cancer cells through dietary manipulation: methods and clinical implications

As the link between obesity and metabolic syndrome and cancer becomes clearer, the need to determine the optimal way to incorporate dietary manipulation in the treatment of cancer patients becomes increasingly important. Metabolic-based therapies, such as caloric restriction, intermittent fasting and a ketogenic diet, have the ability to decrease the incidence of spontaneous tumors and slow the growth of primary tumors, and may have an effect on distant metastases in animal models. Despite the abundance of preclinical data demonstrating the benefit of dietary modification for cancer, to date there are few clinical trials targeting diet as an intervention for cancer patients. We hypothesize that this may be due, in part, to the fact that several different types of diet modification exist with no clear recommendations regarding the optimal method. This article will delineate three commonly used methods of dietary manipulation to assess the potential of each as a regimen for cancer therapy.

MicroRNA expression altered by diet: Can food be medicinal?

As the link between metabolism and major disease processes becomes more well-defined, the identification of key molecular targets is leading to new therapeutic strategies. As a result, small non-coding RNA molecules that regulate gene expression via epigenetic alterations, microRNAs have been identified as regulators of these metabolic processes. In the last decade, dietary interventions have been used to change metabolism and to potentially alter disease progression and clinical outcomes. These interventions have been linked, at a molecular level, to microRNAs. This review will summarize the role of various dietary strategies on the expression of several microRNA families.

The metastatic potential of triple-negative breast cancer is decreased via caloric restriction-mediated reduction of the miR-17~92 cluster

Caloric restriction (CR) has been shown to cause tumor regression in models of triple-negative breast cancer (TNBC), and the regression is augmented when coupled with ionizing radiation (IR). In this study, we sought to determine if the molecular interaction between CR and IR could be mediated by microRNA (miR). miR arrays revealed 3 miRs in the miR-17~92 cluster as most significantly down regulated when CR is combined with IR. In vivo, CR and IR down regulated miR-17/20 in 2 TNBC models. To elucidate the mechanism by which this cluster regulates the response to CR, cDNA arrays were performed and the top 5 statistically significant gene ontology terms with high fold changes were all associated with extracellular matrix (ECM) and metastases. In silico analysis revealed 4 potential targets of the miR-17~92 cluster related to ECM: collagen 4 alpha 3, laminin alpha 3, and metallopeptidase inhibitors 2 and 3, which were confirmed by luciferase assays. The overexpression or silencing of miR-17/20a demonstrated that those miRs directly affected the ECM proteins. Furthermore, we found that CR-mediated inhibition of miR-17/20a can regulate the expression of ECM proteins. Functionally, we demonstrate that CR decreases the metastatic potential of cells which further demonstrates the importance of the ECM. In conclusion, CR can be used as a potential treatment for cancer because it may alter many molecular targets concurrently and decrease metastatic potential for TNBC.

Caloric restriction coupled with radiation decreases metastatic burden in triple negative breast cancer

ABSTRACT Purpose: Metastatic breast cancer is devastating and triple negative breast cancers (TNBC) have a higher propensity for metastasis. Improved local control upfront in this aggressive cancer could potentially decrease its propensity toward metastasis. We sought to determine if using caloric restriction (CR) as a systemic therapy, combined with radiation therapy (IR) to the primary tumor, may impact metastatic disease. Methods: An orthotopic mouse model using a highly metastatic, luciferase-tagged TNBC cell line (4T1), was used to generate palpable tumors. Mice were then treated with CR, IR, and a combination of the two. In vivo imaging was performed for metastatic evaluation. Molecular evaluation of the tumors was performed, generating a mechanistic hypothesis for CR, which was then tested with pertinent pathway inhibition in the model. Results: CR significantly increased the time to developing metastases, decreased the overall number and volume of lung metastases, and increased survival. CR decreased proliferation, increased apoptosis and globally downregulated the IGF-1R signaling pathway. Adding an IGF-1R/INSR inhibitor to local IR in vivo accomplished a decrease in metastases similar to CR plus IR, demonstrating the importance of the IGF-1R signaling pathway, and underscoring it as a possible mechanism for CR. Conclusions: CR decreased metastatic burden and therefore may complement cytotoxic therapies being used in the clinical setting for metastatic disease. Downregulation of the IGF-1R pathway, is in part responsible for this response and modulating IGF-1R directly resulted in similar improved progression-free survival. The novel use of CR has the potential to enhance clinical outcomes for patients with metastatic breast cancer.

Abstract 5189: Caloric restriction augments the chemotherapeutic response in a murine triple negative breast cancer model

Purpose: Triple negative breast cancers (TNBC) are a highly aggressive subtype of breast cancer, linked with a poor prognosis. TNBC tumors have a higher propensity for metastasis and unfortunately have fewer treatment options due to their lack of estrogen, progesterone or Her-2/neu receptors. We sought to determine if caloric restriction (CR) could augment the response of chemotherapy including docetaxel and cisplatin in a TNBC model and improve survival. Methods: An orthotopic mouse model using a highly metastatic, luciferase-tagged TNBC cell line (4T1), was used to generate palpable tumors. Mice were then treated with CR, cisplatin alone, docetaxel alone or a combination of CR and chemotherapy. Three times a week, primary tumors were measured with calipers and in vivo imaging was performed to evaluate the metastatic burden of disease. Molecular evaluation of the tumors was performed, generating a mechanistic hypothesis for increased sensitivity to chemotherapy. Results: Combining either docetaxel or cisplatin with CR, significantly decreased the rate of primary tumor growth (p Conclusions: CR augments the effect of systemic chemotherapy in an aggressive TNBC mouse model, in part by decreasing the inflammatory response. The novel use of CR in combination with systemic chemotherapy has the potential to enhance clinical outcomes for patients with triple negative breast cancer and should be tested in the clinical setting. Citation Format: Brittany Simone, Tu Dan, Ajay Palagani, Meredith LaRose, Jason E. Savage, Nicole Simone. Caloric restriction augments the chemotherapeutic response in a murine triple negative breast cancer model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 5189.

Radiation Therapy for Melanoma

Radiotherapy works by inducing DNA damage in cancer cells, and there are several different methods of radiotherapy delivery including external beam radiotherapy, stereotactic radiosurgery, stereotactic body radiotherapy, radiospheres, brachytherapy, and particle therapy. Historically, melanoma has been deemed a radioresistant tumor, due to early in vitro studies demonstrating a broad shoulder in cell survival curves as well as a high repair rate, inferring a better tumor response with higher radiation doses. For this reason, hypofractionated regimens have become commonplace in the treatment of melanoma given the tolerability, convenience, and low risk of late effects. Nonetheless, in the treatment of primary melanoma, maximal safe surgical resection offers the greatest likelihood of local control. Radiotherapy as a primary treatment is often offered in well-defined situations, such as medical inoperability due to patient comorbidities or tumor location. Clinically, radiation oncologists most frequently see patients with melanoma for consultation in regard to palliation of metastatic disease (for example, stereotactic radiosurgery for brain metastasis or stereotactic body radiotherapy for lung metastasis). The multiple advancements (including technological developments as well as evolution of systemic therapy and immunotherapy) in the treatment of patients with melanoma highlight the importance of multidisciplinary management in this disease.

Caloric restriction counteracts chemotherapy-induced inflammation and increases response to therapy in a triple negative breast cancer model

ABSTRACT Triple negative breast cancer (TNBC) is a heterogeneous disease that has no available targeted therapies. Previously, we have shown that caloric restriction (CR) can augment the effects of radiation therapy in a TNBC mouse model. To build upon this, we now present data regarding the combination of chemotherapy and CR in the same 4T1 model. Chemotherapy can induce inflammation that breeds resistance to therapy. We propose CR as a mechanism to decrease chemotherapy-induced inflammation and increase efficacy of therapy. 12-week old Balb/c mice were orthotopically injected with a syngeneic triple negative breast cancer cell line (4T1) and were treated in one of six cohorts: ad lib fed (AL), 30% reduction in calorie intake (CR), cisplatin or docetaxol alone or a combination CR+cisplatin/docetaxol. Mice in the cohorts receiving chemotherapy+CR had longer overall survival (12 ± 2 days) as compared to the AL group. These mice also demonstrated less lung metastases at the final time point of in vivo imaging. In addition, downregulation of the IGF-1R and IRS signaling pathways were noted most significantly in those mice receiving combination therapy. Lastly, serum from these mice demonstrated an increase in inflammatory cytokines TNF-α and IL-1β in response to chemotherapy alone. This increase was dampened by the addition of CR. Taken together, these data suggest that while chemotherapy is effective in TNBC, it can cause inflammation, which can be a driver of resistance to therapy. This chemotherapy-induced inflammation can be reversed with the use of CR as a nontoxic adjunct to treatment.

Re: Elevated BMI might more significantly affect the outcome negatively in luminal type breast cancer patients with brain metastases

We want to thank Dr. Altundag for expanding on the limitations of the current study [1]. We agree that further studies are needed to determine how metabolic factors contribute to the prognostic outcome of brain metastases originating from each breast cancer subtype. A limitation of our current study is that we did not have adequate patient numbers to elucidate the prognostic significance of how both obesity and diabetes affect each specific molecular subtypes. We also do not have the matched subtype information for both the primary tumor and brain metastases to identify possible discordance because many patients at our institution do not have a biopsy of their brain metastases if they have other known systemic metastases. However, our group previously published that the discordance rate is approximately 20%, and we agree that it could warrant further investigation on a larger scale [2]. Despite these shortcomings, we would like to highlight several prospective studies that have shown benefit to weight management and dietary interventions with patients of all breast cancer subtypes. The Nurses’ Health Initiative was a prospective study which demonstrated decreased rates of recurrence for breast cancer patients who were able to maintain or decrease their weight compared with those who gained weight after diagnosis [3]. It has also been demonstrated in the Women’s Intervention Nutrition Study (WINS) that a nutritional intervention is beneficial for all molecular subtypes and in fact, the largest benefit was noted for women with estrogen-negative breast cancers [4]. Given these data, we extrapolate that metabolic factors including BMI and diabetes will likely play a role in brain metastases outcomes from breast cancer regardless of molecular subtype, but acknowledge that further investigation is warranted.

The design and implementation of caloric restriction for oncology research (CaReFOR): Is starving cancer cells in the clinical realm feasible?

Metabolic alterations are now known to underly cancer growth and progression and therapeutic options are being designed to target dysregulation of metabolism. Using dietary alterations in the treatment of cancer, would be an idea way to intervene in a non-toxic manner. While nutritional interventions have been previously used in the setting of cancer prevention and survivorship, we propose using diet as a cancer therapeutic. Preclinical data demonstrate that caloric restriction (CR) augments radiation therapy by decreasing growth of tumor cells and increasing overall survival. We have therefore designed and implemented a clinical trial to determine if caloric restriction could be tolerated in the clinic during cancer therapy. The CaRe FOR Study: A Pilot Trial Evaluating Caloric Restriction for Oncology Research in Early Stage Breast Cancer Patients. Patients with early stage breast cancer, who require breast radiation have been enrolled. The patients undergo a 10 week CR program, during which they reduce their baseline calories by 25% for 2 weeks pre-radiation, 6 weeks during radiation, and 2 weeks post-treatment. The primary endpoint is to determine if breast cancer patients can adhere to CR during radiation therapy. After enrolling, patients log their baseline caloric intake in an online food diary for one week and a calorie target is established by the provider by calculating a 25% reduction. Patients begin dietary alterations after they receive personalized dietary counseling and behavioral modification lessons adapted from the Diabetes Prevention Program, which both continue through the 10 week program. Secondary parameters will determine if an objective measure can be used to monitor patient adherence in the future and include weight and body composition measures, serum biomarkers, quality of life parameters and treatment toxicity. Here, the steps involved in trying to design a successful clinical trial using CR concurrently with standard cancer treatment such as radiation will be outlined. The long-term goal of the study is to be able to guide methods by which dietary interventions can be successfully implemented for all cancer patients and and to demonstrate that CR is a viable treatment option.. This commentary will provide insight into methods to design clinical trials using dietary alterations. Correspondence to: Nicole L. Simone, MD, Bodine Cancer Center, Department of Radiation Oncology, PA 19107, Philadelphia, Tel: (215) 503-0554; E-mail: Nicole.simone@jeffersonhospital.org