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Breast cancer brain metastasis (BCBM) typically results in an end-stage diagnosis and is hindered by a lack of brain-penetrant drugs. Tumors in the brain rely on the conversion of acetate to acetyl-CoA by the enzyme acetyl-CoA synthetase 2 (ACSS2), a key regulator of fatty acid synthesis and protein acetylation. Here, we used a computational pipeline to identify novel brain-penetrant ACSS2 inhibitors combining pharmacophore-based shape screen methodology with absorption, distribution, metabolism, and excretion (ADME) property predictions. We identified compounds AD-5584 and AD-8007 that were validated for specific binding affinity to ACSS2. Treatment of BCBM cells with AD-5584 and AD-8007 leads to a significant reduction in colony formation, lipid storage, acetyl-CoA levels and cell survival in vitro. In an ex vivo brain-tumor slice model, treatment with AD-8007 and AD-5584 reduced pre-formed tumors and synergized with irradiation in blocking BCBM tumor growth. Treatment with AD-8007 reduced tumor burden and extended survival in vivo. This study identifies selective brain-penetrant ACSS2 inhibitors with efficacy towards breast cancer brain metastasis. [ABSTRACT FROM AUTHOR]

PURPOSE: Traditional methods of evaluating cardiotoxicity focus on radiation doses to the heart. Functional imaging has the potential to provide improved prediction for cardiotoxicity for patients with lung cancer. Fluorine-18 (18F) fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) imaging is routinely obtained in a standard cancer staging workup. This work aimed to develop a radiomics model predicting clinical cardiac assessment using 18F-FDG PET/CT scans before thoracic radiation therapy. METHODS: Pretreatment 18F-FDG PET/CT scans from three study populations (N = 100, N = 39, N = 70) were used, comprising two single-institutional protocols and one publicly available data set. A clinician (V.J.) classified the PET/CT scans per clinical cardiac guidelines as no uptake, diffuse uptake, or focal uptake. The heart was delineated, and 210 novel functional radiomics features were selected to classify cardiac FDG uptake patterns. Training data were divided into training (80%)/validation (20%) sets. Feature reduction was performed using the Wilcoxon test, hierarchical clustering, and recursive feature elimination. Ten-fold cross-validation was carried out for training, and the accuracy of the models to predict clinical cardiac assessment was reported. RESULTS: From 202 of 209 scans, cardiac FDG uptake was scored as no uptake (39.6%), diffuse uptake (25.3%), and focal uptake (35.1%), respectively. Sixty-two independent radiomics features were reduced to nine clinically pertinent features. The best model showed 93% predictive accuracy in the training data set and 80% and 92% predictive accuracy in two external validation data sets. CONCLUSION: This work used an extensive patient data set to develop a functional cardiac radiomic model from standard-of-care 18F-FDG PET/CT scans, showing good predictive accuracy. The radiomics model has the potential to provide an automated method to predict existing cardiac conditions and provide an early functional biomarker to identify patients at risk of developing cardiac complications after radiotherapy. Novel radiomics model predicts cardiac toxicity from 18F-FDG PET/CT scans with high accuracy. [ABSTRACT FROM AUTHOR]

The circadian system, a vital temporal regulator influencing physiological processes, has implications for cancer development and treatment response. Our study assessed circadian timing's impact on whole-brain radiotherapy outcomes in brain metastases for personalized cancer therapy insights. The aim of the study was to evaluate circadian influence on radiation treatment timing and its correlation with clinical outcomes and to identify patient populations benefiting from interventions synchronizing circadian rhythms, considering subgroup differences and potential disparities. An IRB-approved retrospective analysis of 237 patients undergoing whole-brain radiotherapy for brain metastases (2017–2021), receiving over 80% of treatments in the morning or afternoon, was performed. Survival analyses utilized Kaplan–Meier curves. This was a single-institution study involving patients receiving whole-brain radiotherapy. Demographic, disease, and socioeconomic parameters from electronic medical records were collected. Morning treatment (n = 158) showed a trend toward improved overall survival vs. afternoon (n = 79); the median survival was 158 vs. 79 days (p = 0.20, HR = 0.84, CI95% 0.84–0.91). Subgroup benefits for morning treatment in females (p = 0.04) and trends in controlled primary disease (p = 0.11) and breast cancer metastases (p = 0.08) were observed. Black patients exhibited diminished circadian influence. The present study emphasized chronobiological factors' relevance in brain metastases radiation therapy. Morning treatment correlated with improved survival, particularly in specific subgroups. Potential circadian influence disparities were identified, laying a foundation for personalized cancer therapy and interventions synchronizing circadian rhythms for enhanced treatment efficacy. [ABSTRACT FROM AUTHOR]

A meta-analysis of 252 studies conducted between 1997 and 2023 on dietary interventions in cancer patients found that the majority of these studies focused on feasibility, adherence to diet, weight and body composition, or translational endpoints rather than primary endpoints related to dietary interventions and cancer outcomes. Only 20 trials had a primary endpoint designed to detect an improvement in cancer outcomes, and of those, only 8 met their primary endpoint. However, many of the studies that met their endpoint lacked power calculations, and the remainder failed to meet their enrollment criteria. The review did not account for behavioral factors or engagement levels of the interventions, and did not assess the risk of bias. The study suggests that more rigorous research is needed in this area to determine the impact of dietary changes on cancer outcomes. [Extracted from the article]

Simple Summary: Because systemic barriers contribute to the cancer disparities seen among LGBTQ+ patients, we asked physicians about their perceptions on cancer screenings for different subpopulations of this community. We also asked how many of these physicians had received LGBTQ+-specific training, whether they acknowledged that a patient's LGBTQ+ status can affect their health needs, whether they felt confident in understanding these patients' concerns, and whether they would feel comfortable being listed as an LGBTQ+-friendly practice. We also looked for relationships between their responses to certain questions and their self-reported gender, medical specialty, geographic location, and number of years of experience. The survey responses show a lack of agreement among physicians, a general willingness to learn how to better serve LGBTQ+ patients, and likely benefits of LGBTQ+-related training for physicians. Based on our results, we discuss potential areas for improvement in healthcare delivery and future research, including the need for clearer cancer screening standards for LGBTQ+ subpopulations. The LGBTQ+ community experiences cancer disparities due to increased risk factors and lower screening rates, attributable to health literacy gaps and systemic barriers. We sought to understand the experiences, perceptions, and knowledge base of healthcare providers regarding cancer screening for LGBTQ+ patients. A 20-item IRB-approved survey was distributed to physicians through professional organizations. The survey assessed experiences and education regarding the LGBTQ+ community and perceptions of patient concerns with different cancer screenings on a 5-point Likert scale. Complete responses were collected from 355 providers. Only 100 (28%) reported past LGBTQ+-related training and were more likely to be female (p = 0.020), have under ten years of practice (p = 0.014), or practice family/internal medicine (p < 0.001). Most (85%) recognized that LGBTQ+ subpopulations experience nuanced health issues, but only 46% confidently understood them, and 71% agreed their clinics would benefit from training. Family/internal medicine practitioners affirmed the clinical relevance of patients' sexual orientation (94%; 62% for medical/radiation oncology). Prior training affected belief in the importance of sexual orientation (p < 0.001), confidence in understanding LGBTQ+ health concerns (p < 0.001), and willingness to be listed as "LGBTQ+-friendly" (p = 0.005). Our study suggests that despite a paucity of formal training, most providers acknowledge that LGBTQ+ patients have unique health needs. Respondents had a lack of consensus regarding cancer screenings for lesbian and transgender patients, indicating the need for clearer screening standards for LGBTQ+ subpopulations and educational programs for providers. [ABSTRACT FROM AUTHOR]

Purpose: This study examined the gender composition of career development award applicants and grant review panels during the pandemic compared with that beforehand. Methods: Data were collected from 14 Health Research Alliance (HRA) organizations, which fund biomedical research and training. HRA members provided the gender of grant applicants and grant reviewers during the pandemic (April 1, 2020, to February 28, 2021) and prepandemic (April 1, 2019, to February 29, 2020). The signed-rank test compared medians and the chi square test compared the overall gender distribution. Results: The total number of applicants was similar during the pandemic (N = 3,724) and prepandemic (N = 3,882) periods, as was the percentage of women applicants (45.2% pandemic vs. 44.9% prepandemic, p = 0.78). The total number of men and women grant reviewers declined during the pandemic (N = 856) compared with that pre-pandemic (N = 1,689); this decrease was driven by a change for the largest funder. Also driven by changes for this one funder, the percentage of total grant reviewers who were women increased significantly during the pandemic (45.9%) compared with that during prepandemic (38.8%; p = 0.001), but the median percentage of women grant reviewers across organizations remained similar during the pandemic (43.6%) and prepandemic periods (38.2%; p = 0.53). Conclusions: In a sample of research organizations, the gender composition of grant applicants and grant review panels remained similar, except for the review panel composition for one large funder. Given evidence from other studies that have revealed gender differences in other career and life experiences of scientists during the pandemic, ongoing evaluation of women's representation in grant submission and review mechanisms is essential. [ABSTRACT FROM AUTHOR]

Background: Dietary intake is a powerful modifiable factor that influences cancer risk; however, most US adults do not adhere to dietary guidelines for cancer prevention. One promising pathway for improving dietary adherence is targeting grocery shopping habits. Interventions might facilitate healthy grocery choices, with a combination of mHealth and traditional methods, by promoting the salience of dietary goals while shopping, enhancing motivation to make dietary changes, and increasing household support for healthy food purchasing. Objective: This pilot study will assess feasibility and acceptability of intervention components designed to improve adherence to dietary guidelines for cancer prevention (preliminary aim). The primary aim of the study is to quantify the effect of each intervention component, individually and in combination, on dietary intake (primary aim) and grocery store food purchases (exploratory aim). Mediation analyses will be conducted to understand the mechanisms of action (goal salience, motivation, and household support--secondary aims). The overarching goal is to optimize an mHealth intervention to be tested in a future fully powered clinical trial. Methods: The study enrolled adults (N=62) with low adherence to dietary recommendations for cancer prevention. In a 20-week program, all participants attend a nutrition education workshop and receive weekly educational messages through an app. A factorial design is used to test 4 intervention components: (1) location-triggered messages: educational messages are delivered when arriving at grocery stores; (2) reflections on the benefits of change: content is added to messages to encourage reflection on anticipated benefits of healthy eating, and participants attend an additional workshop session and 3 coach calls on this topic; (3) coach monitoring: food purchases are monitored digitally by a coach who sends personalized weekly app messages and conducts 3 coaching calls that focus on feedback about purchases; and (4) household support: another adult in the household receives messages designed to elicit support for healthy food purchasing, and support is addressed in 3 coach calls and an extra workshop session attended by the index participant and household member. Assessments are completed at weeks 0, 10, and 20 using self-report measures, as well as objective capture of grocery data from the point of purchase using store loyalty accounts. Results: The National Cancer Institute funded this study (R21CA252933) on July 7, 2020. Participant recruitment began in the spring of 2021 and concluded with the successful enrollment of 62 participants. Data collection is expected to be completed in the summer of 2022, and results are expected to be disseminated in the summer of 2023. Conclusions: The results of this study will inform the development of scalable interventions to lower cancer risk via changes in dietary intake. [ABSTRACT FROM AUTHOR]

Purpose: A disparity exists in cancer screening rates for the Sexual and Gender Minority (SGM) community. We sought to understand the perceptions and baseline knowledge of cancer screening among SGM community members.Methods: Survey administered via social media from June 2018 to October 2018. We asked 31 questions focused on cancer screening, human papillomavirus, emotional distress, and experience with the health care system. Those included were 18 years or older. Cancer screening attitudes and knowledge, as well as perceptions of the health care system were investigated.Results: There were 422 respondents analyzed: 24.6% identified as female, 25.5% as male, 40.1% transgender, and 9.6% as other. 65.4% of the SGM community is not certain what cancer screening to do for themselves. Only 27.3% and 55.7% knew that HPV was a risk factor associated with head and neck cancer and anal cancer, respectively. Half stated their emotional distress prevents them from getting cancer screening. It was identified that process changes in making appointments, comforts during the visit, and formal training for physicians and nurses could increase cancer screening compliance for this community. The transgender population had a trend in more gaps in knowledge of appropriate cancer screening and significant excess emotional distress.Conclusion: Gaps in cancer screening knowledge and emotional and financial distress may be responsible for the disparity of lower cancer screening rates for the SGM population and the transgender population may be most at risk. Appreciating the cancer screening concerns of the SGM population can help shape future clinical and institutional approaches to improve health care delivery. [ABSTRACT FROM AUTHOR]

Background: Metastatic cancer is incurable and understanding the molecular underpinnings is crucial to improving survival for our patients. The IGF-1/Akt signaling pathway is often impaired in cancer leading to its progression and metastases. Diet modification is known to alter the IGF-1/Akt pathway and affect the expression of microRNA involved in tumor initiation, growth and metastases. Liver metastases are one of the most common type of metastases in breast and colon cancer. In the present study, we looked at the effect of diet modification on the expression of microRNA in normal liver and liver with breast cancer metastases using in vivo model. Methodology: 6-month-old C57BL/6 J mice were put on either an ad libitum (AL) diet, or 40% calorie restricted (CR) diet or were fasted for 24 h (FA) before sacrifice. MicroRNA array analysis, western blot and qRT-PCR were performed using liver tissue to compare the treatment groups. A breast cancer model was also used to study the changes in microRNA expression in liver of a group of BALB/c mice orthotopically injected with 4 T1 cells in the mammary fat pad, put on either an AL or 30% CR diet. Liver and primary tumor tissues were used to perform qRT-PCR to compare the treatment groups. Results: MicroRNA array analysis showed significant changes in miRNA expression in both CR and FA conditions in normal liver. Expression of miR-29 and miR-30 family members was increased in both CR and FA. Western blot analysis of the normal liver tissue showed that CR and FA downregulated the IGF-1/Akt pathway and qRT-PCR showed that the expression of miR-29b, miR-29c, miR-30a and miR-30b were increased with CR and FA. Liver tissue collected from mice in the breast cancer model showed an increase in expression of miR-29b, miR-29c and miR-30b while tumor tissue showed increased expression of miR-29c, miR-30a and miR-30b. Discussion: Members of the miR-29 family are known to target and suppress IGF-1, while members of the miR-30 family are known to target and suppress both IGF-1 and IGF-1R. In the present study, we observe that calorie restriction increased the expression of miR-29 and miR-30 in both the normal liver as well as the liver with breast cancer metastases. These findings suggest that dietary alterations may play a role in the treatment of liver metastasis, which should be evaluated further. [ABSTRACT FROM AUTHOR]

Purpose: Metabolic dysregulation has been implicated as a molecular driver of breast cancer in preclinical studies, especially with respect to metastases. We hypothesized that abnormalities in patient metabolism, such as obesity and diabetes, may drive outcomes in breast cancer patients with brain metastases.Methods: We retrospectively identified 84 consecutive patients with brain metastases from breast cancer treated with intracranial radiation therapy. Radiation was delivered as whole-brain radiation to a median dose of 3000 cGy or stereotactic radiosurgery to a median dose of 2100 cGy. Kaplan Meier curves were generated for overall survival (OS) data and Mantel-Cox regression was performed to detect differences in groups.Results: At analysis, 81 survival events had occurred and the median OS for the entire cohort was 21.7 months. Despite similar modified graded prognostic assessments, resection rates, and receptor status, BMI ≥ 25 kg/m2 (n = 45) was associated with decreased median OS (13.7 vs. 30.6 months; p < 0.001) and median intracranial progression-free survival (PFS) (7.4 vs. 10.9 months; p = 0.04) compared to patients with BMI < 25 kg/m2 (n = 39). Similar trends were observed among all three types of breast cancer. Patients with diabetes (n = 17) had decreased median OS (11.8 vs. 26.2 months; p < 0.001) and median intracranial PFS (4.5 vs. 10.3 months; p = 0.001) compared to non-diabetics (n = 67). On multivariate analysis, both BMI ≥ 25 kg/m2 [HR 2.35 (1.39-3.98); p = 0.002] and diabetes [HR 2.77 (1.454-5.274); p = 0.002] were associated with increased mortality.Conclusions: Elevated BMI or diabetes may negatively impact both overall survival and local control in patients with brain metastases from breast cancer, highlighting the importance of the translational development of therapeutic metabolic interventions. Given its prognostic significance, BMI should be used as a stratification in future clinical trial design in this patient population. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

A preview of the article "microRNA's: The short link between cancer and RT induced DNA damage response" by Chris Wright et al., which appeared in the periodical "Frontiers in Oncology" on May 20, 2014, is presented.

In well-selected patients who choose to pursue breast conservation therapy (BCT) for early-stage breast cancer, partial breast irradiation (PBI) delivered externally or intraoperatively, may be a viable alternative to conventional whole breast irradiation. Two large, contemporary randomized trials have demonstrated breast intraoperative radiotherapy (IORT) to be noninferior to whole breast external beam radiotherapy (EBRT) when assessing for ipsilateral breast tumor recurrence in select patients. Additionally, IORT and other PBI techniques are likely to be more widely adopted in the future because they improve patient convenience by offering an accelerated course of treatment. Coupled with these novel techniques for breast radiotherapy (RT) are distinct toxicity profiles and unique cosmetic alterations that differ from conventional breast EBRT and have the potential to impact disease surveillance and patient satisfaction. This paper will review the level-one evidence for treatment efficacy as well as important secondary endpoints like RT toxicity, breast cosmesis, quality of life, patient satisfaction, and surveillance mammography following BCT with IORT. [ABSTRACT FROM AUTHOR]

Circadian disruption has been linked to cancer development, progression, and radiation response. Clinical evidence to date shows that circadian genetic variation and time of treatment affect radiation response and toxicity for women with breast cancer. At the molecular level, there is interplay between circadian clock regulators such as PER1, which mediates ATM and p53-mediated cell cycle gating and apoptosis. These molecular alterations may govern aggressive cancer phenotypes, outcomes, and radiation response. Exploiting the various circadian clock mechanisms may enhance the therapeutic index of radiation by decreasing toxicity, increasing disease control, and improving outcomes. We will review the body's natural circadian rhythms and clock gene-regulation while exploring preclinical and clinical evidence that implicates chronobiological disruptions in the etiology of breast cancer. We will discuss radiobiological principles and the circadian regulation of DNA damage responses. Lastly, we will present potential rational therapeutic approaches that target circadian pathways to improve outcomes in breast cancer. Understanding the implications of optimal timing in cancer treatment and exploring ways to entrain circadian biology with light, diet, and chronobiological agents like melatonin may provide an avenue for enhancing the therapeutic index of radiotherapy. [ABSTRACT FROM AUTHOR]

Understanding metabolic and immune regulation inherent to patient populations is key to improving the radiation response for our patients. To date, radiation therapy regimens are prescribed based on tumor type and stage. Patient populations who are noted to have a poor response to radiation such as those of African American descent, those who have obesity or metabolic syndrome, or senior adult oncology patients, should be considered for concurrent therapies with radiation that will improve response. Here, we explore these populations of breast cancer patients, who frequently display radiation resistance and increased mortality rates, and identify the molecular underpinnings that are, in part, responsible for the radiation response and that result in an immune-suppressive tumor microenvironment. The resulting immune phenotype is discussed to understand how antitumor immunity could be improved. Correcting nutrient deficiencies observed in these populations should be considered as a means to improve the therapeutic index of radiation therapy. [ABSTRACT FROM AUTHOR]

Calorie restriction (CR), or a diet modification aiming to reduce the total intake of calories by20%-40%, has been shown to increase longevity across multiple species. Recently, there has been growing interest in investigating the potential role of CR as a treatment intervention for age-related diseases, such as cancer, because an increasing body of literature has demonstrated a metabolic component to both carcinogenes is and tumor progression. In fact, many of the molecular pathways that are altered with CR are also known to be altered in cancer. Therefore, manipulation of these pathways using CR can render cancer cells, and most notably breast cancer cells, more susceptible to standard cytotoxic treatment with radiation and chemotherapy. In this review article we demonstrate the laboratory and clinical evidence that exists for CR and show compelling evidence through the molecular pathways CR induces about how it may be used as a treatment in tandem with radiation therapy to improve our rates of disease control. [ABSTRACT FROM AUTHOR]

Approximately one-third of all breast cancer patients experience local recurrence of their tumor after initial treatment. As initial treatment often employs the use of radiation therapy (RT), the standard of care for local breast cancer recurrence after initial breast conserving therapy has traditionally been surgical intervention with mastectomy. However, recent attempts to preserve the intact breast after recurrence with local excision have revealed a potential need for RT in addition to repeat breast conserving surgery as rates of local failure with resection alone remain high. Additionally, local recurrence following initial mastectomy and chest wall RT can be treated with reirradiation to increase local control. Repeating RT, however, in a previously irradiated area, is a complex treatment strategy, as the clinician must carefully balance maximizing treatment effectiveness while minimizing treatment-related toxicity. As a result, physicians have been hesitant to treat recurrent disease with repeat RT with limited data. Results from the current literature are promising and current clinical trials are underway to explore reirradiation modalities which will provide additional information on treatment-related toxicity and outcomes. This paper will review the current literature on repeat radiation therapy for locally recurrent breast cancer. [ABSTRACT FROM AUTHOR]

Metabolic syndrome, which can include weight gain and central obesity, elevated seruminsulin and glucose, and insulin resistance, has been strongly associated with breast cancer recurrence and worse outcomes after treatment. Epidemiologic and prospective data do not show conclusive evidence as to which dietary factors may be responsible for these results. Current strategies employ low-fat diets which emphasize supplementing calories with increased intake of fruit, grain, and vegetable carbohydrate sources. Although results thus far have been inconclusive, recent randomized trials employing markedly different dietary strategies in noncancer patients may hold the key to reducing multiple risk factors in metabolic syndrome simultaneously which may prove to increase the long-term outcome of breast cancer patients and decrease recurrences. Since weight gain after breast cancer treatment confers a poor prognosis and may increase recurrence rates, large-scale randomized trials are needed to evaluate appropriate dietary interventions for our breast cancer patients. [ABSTRACT FROM AUTHOR]

Genotoxic stressors, such as radiation, induce cellular damage that activates pre-programmed repair pathways, some of which involve microRNAs (miRNA) that alter gene expression. The let-7 family of miRNA regulates multiple cellular processes including cell division and DNA repair pathways. However, the role and mechanism underlying regulation of let-7 genes in response to stress have yet to be elucidated. In this study we demonstrate that let-7a and let-7b expression decreases significantly following exposure to agents that induce stress including ionizing radiation. This decrease in expression is dependent on p53 and ATM in vitro and is not observed in a p53-/- colon cancer cell line (HCT116) or ATM-/- human fibroblasts. Chromatin Immunoprecipitation (ChIP) analysis showed p53 binding to a region upstream of the let-7 gene following radiation exposure. Luciferase transient transfections demonstrated that this p53 binding site is necessary for radiation-induced decreases in let-7 expression. A radiation-induced decrease in let-7a and let-7b expression is also observed in radiation-sensitive tissues in vivo and correlates with altered expression of proteins in p53-regulated pro-apoptotic signaling pathways. In contrast, this decreased expression is not observed in p53 knock-out mice suggesting that p53 directly repress let-7 expression. Exogenous expression of let-7a and let-7b increased radiation-induced cytotoxicity in HCT116 p53+/+ cells but not HCT116 p53-/- cells. These results are the first demonstration of a mechanistic connection between the radiation-induced stress response and the regulation of miRNA and radiation-induced cytotoxicity and suggest that this process may be a molecular target for anticancer agents. [ABSTRACT FROM AUTHOR]

Background: The histamine receptor-1 (H1)-antagonist, loratadine has been shown to inhibit growth of human colon cancer xenografts in part due to cell cycle arrest in G2/M. Since this is a radiation sensitive phase of the cell cycle, we sought to determine if loratadine modifies radiosensitivity in several human tumor cell lines with emphasis on human colon carcinoma (HT29). Methods: Cells were treated with several doses of loratadine at several time points before and after exposure to radiation. Radiation dose modifying factors (DMF) were determined using full radiation dose response survival curves. Cell cycle phase was determined by flow cytometry and the expression of the cell cycle-associated proteins Chk1, pChk1ser345, and Cyclin B was analyzed by western blot. Results: Loratadine pre-treatment of exponentially growing cells (75 μM, 24 hours) increased radiation-induced cytotoxicity yielding a radiation DMF of 1.95. However, treatment of plateau phase cells also yielded a DMF of 1.3 suggesting that mechanisms other than cell cycle arrest also contribute to loratadine-mediated radiation modification. Like irradiation, loratadine initially induced G2/M arrest and activation of the cell-cycle associated protein Chk1 to pChk1ser345, however a subsequent decrease in expression of total Chk1 and Cyclin B correlated with abrogation of the G2/M checkpoint. Analysis of DNA repair enzyme expression and DNA fragmentation revealed a distinct pattern of DNA damage in loratadine-treated cells in addition to enhanced radiation-induced damage. Taken together, these data suggest that the observed effects of loratadine are multifactorial in that loratadine 1) directly damages DNA, 2) activates Chk1 thereby promoting G2/M arrest making cells more susceptible to radiation-induced DNA damage and, 3) downregulates total Chk1 and Cyclin B abrogating the radiation-induced G2/M checkpoint and allowing cells to re-enter the cell cycle despite the persistence of damaged DNA. Conclusions: Given this unique possible mechanism of action, loratadine has potential as a chemotherapeutic agent and as a modifier of radiation responsiveness in the treatment of cancer and, as such, may warrant further clinical evaluation. [ABSTRACT FROM AUTHOR]

Background: MicroRNAs (miRNAs) are small, highly conserved, non-coding RNA that alter protein expression and regulate multiple intracellular processes, including those involved in the response to cellular stress. Alterations in miRNA expression may occur following exposure to several stress-inducing anticancer agents including ionizing radiation, etoposide, and hydrogen peroxide (H2O2). Methodology/Principal Findings: Normal human fibroblasts were exposed to radiation, H2O2, or etoposide at doses determined by clonogenic cell survival curves. Total RNA was extracted and miRNA expression was determined by microarray. Time course and radiation dose responses were determined using RT-PCR for individual miRNA species. Changes in miRNA expression were observed for 17 miRNA species following exposure to radiation, 23 after H2O2 treatment, and 45 after etoposide treatment. Substantial overlap between the miRNA expression changes between agents was observed suggesting a signature miRNA response to cell stress. Changes in the expression of selected miRNA species varied in response to radiation dose and time. Finally, production of reactive oxygen species (ROS) increased with increasing doses of radiation and pre-treatment with the thiol antioxidant cysteine decreased both ROS production and the miRNA response to radiation. Conclusions: These results demonstrate a common miRNA expression signature in response to exogenous genotoxic agents including radiation, H2O2, and etoposide. Additionally, pre-treatment with cysteine prevented radiation-induced alterations in miRNA expression which suggests that miRNAs are responsive to oxidative stress. Taken together, these results imply that miRNAs play a role in cellular defense against exogenous stress and are involved in the generalized cellular response to genotoxic oxidative stress. [ABSTRACT FROM AUTHOR]

Background: Fibrosis is a common side effect after treatment with ionizing radiation. Several methods to ameliorate debilitating fibrosis have been employed but without consistent results. The goal of this pilot study is to determine if Pirfenidone, a novel regulator of cytokine gene expression, has the potential to ameliorate established radiation-induced fibrosis. Methods: Open label, prospective pilot study of 800 mg three times/day, orally administered Pirfenidone was administered to enrolled patients who were had completed radiation therapy and who had established radiation-induced fibrosis. Range of motion (ROM) was assessed using standard measures, and subjective measures of pain, fatigue, disability and global health were measured every three months. Results: Seven patients were enrolled of whom 3 had ROM assessments of 1 site and 2 had ROM assessments of 2 sites. Of these assessments, 6 revealed increased ROM during drug intervention while 1 revealed a decreased ROM. There was an overall improvement in the mental composite score of the SF36 while physical composite score was decreased and the vitality score was unchanged. Two patients were removed from the study because of syncopal episodes. Conclusion: Several patients experienced improved function of at least 25% and reported subjective improvement. Pirfenidone may benefit patients with radiation-induced fibrosis and is worthy of a larger well controlled trial. [ABSTRACT FROM AUTHOR]

Protein arrays are described for screening of molecular markers and pathway targets in patient matched human tissue during disease progression. In contrast to previous protein arrays that immobilize the probe, our reverse phase protein array immobilizes the whole repertoire of patient proteins that represent the state of individual tissue cell populations undergoing disease transitions. A high degree of sensitivity, precision and linearity was achieved, making it possible to quantify the phosphorylated status of signal proteins in human tissue cell subpopulations. Using this novel protein microarray we have longitudinally analysed the state of pro-survival checkpoint proteins at the microscopic transition stage from patient matched histologically normal prostate epithelium to prostate intraepithelial neoplasia (PIN) and then to invasive prostate cancer. Cancer progression was associated with increased phosphorylation of Akt (P<0.04), suppression of apoptosis pathways (P<0.03), as well as decreased phosphorylation of ERK (P<0.01). At the transition from histologically normal epithelium to PIN we observed a statistically significant surge in phosphorylated Akt (P<0.03) and a concomitant suppression of downstream apoptosis pathways which proceeds the transition into invasive carcinoma. Oncogene (2001) 20, 1981–1989. [ABSTRACT FROM AUTHOR]

The article focuses on the role of DNA damage response (DDR) in cancer. Topics discussed include an investigation of microRNAs to further understand the relationship between cancer and DDR, and the fact that microRNAs serve as integrators of the cellular response to reactive oxygen species (ROS) and DNA strand breaks, both of which are results of ionizing radiation.

Simple Summary: miR-21 is an oncogenic microRNA that has been associated with breast tumor growth and metastasis in vitro and is also noted to be upregulated by cytotoxic stressors in model systems and in breast cancer patients who have undergone radiation. In the present study, our findings demonstrate the novel role of miR-21 in vivo for breast cancer initiation and metastases, and in sensitizing tumor cells to cytotoxic therapy by upregulating the FAS/FASL signaling pathway. Breast cancer (BrCa) relies on specific microRNAs to drive disease progression. Oncogenic miR-21 is upregulated in many cancers, including BrCa, and is associated with poor survival and treatment resistance. We sought to determine the role of miR-21 in BrCa tumor initiation, progression and treatment response. In a triple-negative BrCa model, radiation exposure increased miR-21 in both primary tumor and metastases. In vitro, miR-21 knockdown decreased survival in all BrCa subtypes in the presence of radiation. The role of miR-21 in BrCa initiation was evaluated by implanting wild-type miR-21 BrCa cells into genetically engineered mouse models where miR-21 was intact, heterozygous or globally ablated. Tumors were unable to grow in the mammary fat pads of miR-21−/− mice, and grew in ~50% of miR-21+/− and 100% in miR-21+/+ mice. The contribution of miR-21 to progression and metastases was tested by crossing miR-21−/− mice with mice that spontaneously develop BrCa. The global ablation of miR-21 significantly decreased the tumorigenesis and metastases of BrCa, while sensitizing tumors to radio- and chemotherapeutic agents via Fas/FasL-dependent apoptosis. Therefore, targeting miR-21 alone or in combination with various radio or cytotoxic therapies may represent novel and efficacious therapeutic modalities for the future treatment of BrCa patients. [ABSTRACT FROM AUTHOR]

For the past 100 years, oncologists have relentlessly pursued the destruction of tumor cells by surgical, chemotherapeutic or radiation oncological means. Consistent with this focus, treatment plans are typically based on key characteristics of the tumor itself such as disease site, histology and staging based on local, regional and systemic dissemination. Precision medicine is similarly built on the premise that detailed knowledge of molecular alterations of tumor cells themselves enables better and more effective tumor cell destruction. Recently, host factors within the tumor microenvironment including the vasculature and immune systems have been recognized as modifiers of disease progression and are being targeted for therapeutic gain. In this review, we argue that—to optimize the impact of old and new treatment options—we need to take account of an epidemic that occurs independently of—but has major impact on—the development and treatment of malignant diseases. This is the rapidly increasing number of patients with excess weight and its' attendant metabolic consequences, commonly described as metabolic syndrome. It is well established that patients with altered metabolism manifesting as obesity, metabolic syndrome and chronic inflammation have an increased incidence of cancer. Here, we focus on evidence that these patients also respond differently to cancer therapy including radiation and provide a perspective how exercise, diet or pharmacological agents may be harnessed to improve therapeutic responses in this patient population. [ABSTRACT FROM AUTHOR]