Acetate Production from Glucose and Coupling to Mitochondrial Metabolism in Mammals.

Acetate is a major nutrient that supports acetyl-coenzyme A (Ac-CoA) metabolism and thus lipogenesis and protein acetylation. However, its source is unclear. Here, we report that pyruvate, the end product of glycolysis and key node in central carbon metabolism, quantitatively generates acetate in mammals. This phenomenon becomes more pronounced in the context of nutritional excess, such as during hyperactive glucose metabolism. Conversion of pyruvate to acetate occurs through two mechanisms: (1) coupling to reactive oxygen species (ROS) and (2) neomorphic enzyme activity from keto acid dehydrogenases that enable function as pyruvate decarboxylases. Further, we demonstrate that de novo acetate production sustains Ac-CoA pools and cell proliferation in limited metabolic environments, such as during mitochondrial dysfunction or ATP citrate lyase (ACLY) deficiency. By virtue of de novo acetate production being coupled to mitochondrial metabolism, there are numerous possible regulatory mechanisms and links to pathophysiology.

The microRNA-183/96/182 cluster inhibits lung cancer progression and metastasis by inducing an interleukin-2-mediated antitumor CD8+ cytotoxic T-cell response.

One of the mechanisms by which cancer cells acquire hyperinvasive and migratory properties with progressive loss of epithelial markers is the epithelial-to-mesenchymal transition (EMT). We have previously reported that in different cancer types, including nonsmall cell lung cancer (NSCLC), the microRNA-183/96/182 cluster (m96cl) is highly repressed in cells that have undergone EMT. In the present study, we used a novel conditional m96cl mouse to establish that loss of m96cl accelerated the growth of Kras mutant autochthonous lung adenocarcinomas. In contrast, ectopic expression of the m96cl in NSCLC cells results in a robust suppression of migration and invasion in vitro, and tumor growth and metastasis in vivo. Detailed immune profiling of the tumors revealed a significant enrichment of activated CD8+ cytotoxic T lymphocytes (CD8+ CTLs) in m96cl-expressing tumors, and m96cl-mediated suppression of tumor growth and metastasis was CD8+ CTL-dependent. Using coculture assays with naïve immune cells, we show that m96cl expression drives paracrine stimulation of CD8+ CTL proliferation and function. Using tumor microenvironment-associated gene expression profiling, we identified that m96cl elevates the interleukin-2 (IL2) signaling pathway and results in increased IL2-mediated paracrine stimulation of CD8+ CTLs. Furthermore, we identified that the m96cl modulates the expression of IL2 in cancer cells by regulating the expression of transcriptional repressors Foxf2 and Zeb1, and thereby alters the levels of secreted IL2 in the tumor microenvironment. Last, we show that in vivo depletion of IL2 abrogates m96cl-mediated activation of CD8+ CTLs and results in loss of metastatic suppression. Therefore, we have identified a novel mechanistic role of the m96cl in the suppression of lung cancer growth and metastasis by inducing an IL2-mediated systemic CD8+ CTL immune response.

Metabolomics in cancer research and emerging applications in clinical oncology.

Cancer has myriad effects on metabolism that include both rewiring of intracellular metabolism to enable cancer cells to proliferate inappropriately and adapt to the tumor microenvironment, and changes in normal tissue metabolism. With the recognition that fluorodeoxyglucose-positron emission tomography imaging is an important tool for the management of many cancers, other metabolites in biological samples have been in the spotlight for cancer diagnosis, monitoring, and therapy. Metabolomics is the global analysis of small molecule metabolites that like other -omics technologies can provide critical information about the cancer state that are otherwise not apparent. Here, the authors review how cancer and cancer therapies interact with metabolism at the cellular and systemic levels. An overview of metabolomics is provided with a focus on currently available technologies and how they have been applied in the clinical and translational research setting. The authors also discuss how metabolomics could be further leveraged in the future to improve the management of patients with cancer.

Dietary methionine influences therapy in mouse cancer models and alters human metabolism.

Nutrition exerts considerable effects on health, and dietary interventions are commonly used to treat diseases of metabolic aetiology. Although cancer has a substantial metabolic component1, the principles that define whether nutrition may be used to influence outcomes of cancer are unclear2. Nevertheless, it is established that targeting metabolic pathways with pharmacological agents or radiation can sometimes lead to controlled therapeutic outcomes. By contrast, whether specific dietary interventions can influence the metabolic pathways that are targeted in standard cancer therapies is not known. Here we show that dietary restriction of the essential amino acid methionine-the reduction of which has anti-ageing and anti-obesogenic properties-influences cancer outcome, through controlled and reproducible changes to one-carbon metabolism. This pathway metabolizes methionine and is the target of a variety of cancer interventions that involve chemotherapy and radiation. Methionine restriction produced therapeutic responses in two patient-derived xenograft models of chemotherapy-resistant RAS-driven colorectal cancer, and in a mouse model of autochthonous soft-tissue sarcoma driven by a G12D mutation in KRAS and knockout of p53 (KrasG12D/+;Trp53-/-) that is resistant to radiation. Metabolomics revealed that the therapeutic mechanisms operate via tumour-cell-autonomous effects on flux through one-carbon metabolism that affects redox and nucleotide metabolism-and thus interact with the antimetabolite or radiation intervention. In a controlled and tolerated feeding study in humans, methionine restriction resulted in effects on systemic metabolism that were similar to those obtained in mice. These findings provide evidence that a targeted dietary manipulation can specifically affect tumour-cell metabolism to mediate broad aspects of cancer outcome.

Transitioning from a COMS-based plaque brachytherapy program to using eye physics plaques and plaque simulator treatment planning system: A single institutional experience.

The aim of this work is to describe the implementation and commissioning of a plaque brachytherapy program using Eye Physics eye plaques and Plaque Simulator treatment planning system based on the experience of one institution with an established COMS-based plaque program. Although commissioning recommendations are available in official task groups publications such as TG-129 and TG-221, we found that there was a lack of published experiences with the specific details of such a transition and the practical application of the commissioning guidelines. The specific issues addressed in this paper include discussing the lack of FDA approval of the Eye Physics plaques and Plaque Simulator treatment planning system, the commissioning of the plaques and treatment planning system including considerations of the heterogeneity corrected calculations, and the implementation of a second check using an FDA-approved treatment planning system. We have also discussed the use of rental plaques, the analysis of plans using dose histograms, and the development of a quality management program. By sharing our experiences with the commissioning of this program this document will assist other institutions with the same task and act as a supplement to the recommendations in the recently published TG-221.

Neutrophils promote tumor resistance to radiation therapy.

Nearly two-thirds of cancer patients are treated with radiation therapy (RT), often with the intent to achieve complete and permanent tumor regression (local control). RT is the primary treatment modality used to achieve local control for many malignancies, including locally advanced cervical cancer, head and neck cancer, and lung cancer. The addition of concurrent platinum-based radiosensitizing chemotherapy improves local control and patient survival. Enhanced outcomes with concurrent chemoradiotherapy may result from increased direct killing of tumor cells and effects on nontumor cell populations. Many patients treated with concurrent chemoradiotherapy exhibit a decline in neutrophil count, but the effects of neutrophils on radiation therapy are controversial. To investigate the clinical significance of neutrophils in the response to RT, we examined patient outcomes and circulating neutrophil counts in cervical cancer patients treated with definitive chemoradiation. Although pretreatment neutrophil count did not correlate with outcome, lower absolute neutrophil count after starting concurrent chemoradiotherapy was associated with higher rates of local control, metastasis-free survival, and overall survival. To define the role of neutrophils in tumor response to RT, we used genetic and pharmacological approaches to deplete neutrophils in an autochthonous mouse model of soft tissue sarcoma. Neutrophil depletion prior to image-guided focal irradiation improved tumor response to RT. Our results indicate that neutrophils promote resistance to radiation therapy. The efficacy of chemoradiotherapy may depend on the impact of treatment on peripheral neutrophil count, which has the potential to serve as an inexpensive and widely available biomarker.

Ultra-rare sarcomas: A consensus paper from the Connective Tissue Oncology Society community of experts on the incidence threshold and the list of entities.

BACKGROUND: Among sarcomas, which are rare cancers, many types are exceedingly rare; however, a definition of ultra-rare cancers has not been established. The problem of ultra-rare sarcomas is particularly relevant because they represent unique diseases, and their rarity poses major challenges for diagnosis, understanding disease biology, generating clinical evidence to support new drug development, and achieving formal authorization for novel therapies. METHODS: The Connective Tissue Oncology Society promoted a consensus effort in November 2019 to establish how to define ultra-rare sarcomas through expert consensus and epidemiologic data and to work out a comprehensive list of these diseases. The list of ultra-rare sarcomas was based on the 2020 World Health Organization classification, The incidence rates were estimated using the Information Network on Rare Cancers (RARECARENet) database and NETSARC (the French Sarcoma Network's clinical-pathologic registry). Incidence rates were further validated in collaboration with the Asian cancer registries of Japan, Korea, and Taiwan. RESULTS: It was agreed that the best criterion for a definition of ultra-rare sarcomas would be incidence. Ultra-rare sarcomas were defined as those with an incidence of approximately ≤1 per 1,000,000, to include those entities whose rarity renders them extremely difficult to conduct well powered, prospective clinical studies. On the basis of this threshold, a list of ultra-rare sarcomas was defined, which comprised 56 soft tissue sarcoma types and 21 bone sarcoma types. CONCLUSIONS: Altogether, the incidence of ultra-rare sarcomas accounts for roughly 20% of all soft tissue and bone sarcomas. This confirms that the challenges inherent in ultra-rare sarcomas affect large numbers of patients.

Effects of chondroitin sulfate proteoglycan 4 (NG2/CSPG4) on soft-tissue sarcoma growth depend on tumor developmental stage.

Sarcomas, and the mesenchymal precursor cells from which they arise, express chondroitin sulfate proteoglycan 4 (NG2/CSPG4). However, NG2/CSPG4's function and its capacity to serve as a therapeutic target in this tumor type are unknown. Here, we used cells from human tumors and a genetically engineered autochthonous mouse model of soft-tissue sarcomas (STSs) to determine NG2/CSPG4's role in STS initiation and growth. Inhibiting NG2/CSPG4 expression in established murine and human STSs decreased tumor volume by almost two-thirds and cell proliferation rate by 50%. NG2/CSPG4 antibody immunotherapy in human sarcomas established as xenografts in mice similarly decreased tumor volume, and expression of a lentivirus blocking NG2/CSPG4 expression inhibited tumor cell proliferation and increased the latency of engraftment. Gene profiling showed that Ng2/Cspg4 deletion altered the expression of genes regulating cell proliferation and apoptosis. Surprisingly, Ng2/Cspg4 deletion at the time of tumor initiation resulted in larger tumors. Gene expression profiling indicated substantial down-regulation of insulin-like growth factor binding protein (Igfbp) genes when Ng2/Cspg4 is depleted at tumor initiation, but not when Ng2/Cspg4 is depleted after tumor initiation. Such differences may have clinical significance, as therapeutic targeting of a signaling pathway such as NG2/CSPG4 may have different effects on cell behavior with tumor progression. NG2/CSPG4 depletion has divergent effects, depending on the developmental stage of sarcoma. In established tumors, IGF signaling is active, and NG2 inhibition targets cell proliferation and apoptosis.

Insights into pediatric rhabdomyosarcoma research: Challenges and goals.

Overall survival rates for pediatric patients with high-risk or relapsed rhabdomyosarcoma (RMS) have not improved significantly since the 1980s. Recent studies have identified a number of targetable vulnerabilities in RMS, but these discoveries have infrequently translated into clinical trials. We propose streamlining the process by which agents are selected for clinical evaluation in RMS. We believe that strong consideration should be given to the development of combination therapies that add biologically targeted agents to conventional cytotoxic drugs. One example of this type of combination is the addition of the WEE1 inhibitor AZD1775 to the conventional cytotoxic chemotherapeutics, vincristine and irinotecan.

Combining precision radiotherapy with molecular targeting and immunomodulatory agents: a guideline by the American Society for Radiation Oncology.

The practice of radiation oncology is primarily based on precise technical delivery of highly conformal, image-guided external beam radiotherapy or brachytherapy. However, systematic research efforts are being made to facilitate individualised radiation dose prescriptions on the basis of gene-expressssion profiles that reflect the radiosensitivity of tumour and normal tissue. This advance in precision radiotherapy should complement those benefits made in precision cancer medicine that use molecularly targeted agents and immunotherapies. The personalisation of cancer therapy, predicated largely on genomic interrogation, is facilitating the selection of therapies that are directed against driver mutations, aberrant cell signalling, tumour microenvironments, and genetic susceptibilities. With the increasing technical power of radiotherapy to safely increase local tumour control for many solid tumours, it is an opportune time to rigorously explore the potential benefits of combining radiotherapy with molecular targeted agents and immunotherapies to increase cancer survival outcomes. This theme provides the basis and foundation for this American Society for Radiation Oncology guideline on combining radiotherapy with molecular targeting and immunotherapy agents.

Rationale and emerging strategies for immune checkpoint blockade in soft tissue sarcoma.

Soft tissue sarcomas (STS) are heterogeneous, mesenchymal malignancies with variable biologic behavior. The primary management for localized STS is surgical resection, which may be combined with neoadjuvant or adjuvant radiation therapy to increase the probability of achieving local control. Many patients with large, high-grade STS develop metastatic disease. Several clinical trials of immune checkpoint blockade for STS have produced promising responses in patients with metastatic disease. In this review, recent and ongoing clinical trials of immune checkpoint inhibition for STS are discussed. The authors explain the rationale for immune checkpoint inhibition and radiation therapy and highlight new studies testing this combination in the neoadjuvant setting for patients with high-risk STS. In addition, they describe novel combinations of immunotherapy with targeted therapies and chemotherapies being tested in the metastatic setting and discuss how these combinations have the potential to be integrated into adjuvant therapy in the future.

Assessment of Response to Transcatheter Arterial Chemoembolization with Doxorubicin-eluting Microspheres: Tumor Biology and Hepatocellular Carcinoma Recurrence in a 5-year Transplant Cohort.

Purpose To assess response to transcatheter arterial chemoembolization (TACE) based on immune markers and tumor biology in patients with hepatocellular carcinoma (HCC) who were bridged to liver transplantation, and to produce an optimized pretransplantation model for posttransplantation recurrence risk. Materials and Methods In this institutional review board-approved HIPAA-compliant retrospective analysis, 93 consecutive patients (73 male, 20 female; mean age, 59.6 years; age range, 23-72 years) underwent TACE with doxorubicin-eluting microspheres (DEB) (hereafter, DEB-TACE) and subsequently underwent transplantation over a 5-year period from July 7, 2011, to May 16, 2016. DEB-TACE response was based on modified Response Evaluation Criteria in Solid Tumors. Imaging responses and posttransplantation recurrence were compared with demographics, liver function, basic immune markers, treatment dose, and tumor morphology. Treatment response and recurrence were analyzed with uni- and multivariate statistics, as well as internal validation and propensity score matching of factors known to affect recurrence to assess independent effects of DEB-TACE response on recurrence. Results Low-grade tumors (grade 0, 1, or 2) demonstrated a favorable long-term treatment response in 87% of patients (complete response, 49%; partial response, 38%; stable disease [SD] or local disease progression [DP], 13%) versus 33% of high-grade tumors (grade 3 or 4) (complete response, 0%; partial response, 33%; SD or DP, 67%) (P < .001). Of the 93 patients who underwent treatment, 82 were followed-up after transplantation (mean duration, 757 days). Recurrence occurred in seven (9%) patients (mean time after transplantation, 635 days). Poor response to DEB-TACE (SD or DP) was present in 86% of cases and accounted for 35% of all patients with SD or DP (P < .001). By using only variables routinely available prior to liver transplantation, a validated model of posttransplantation recurrence risk was produced with a concordance statistic of 0.83. The validated model shows sensitivity of 83.6%, specificity of 82.6%, and negative predictive value of 98.4%, which are pessimistic estimates. Conclusion Response to DEB-TACE is correlated with tumor biology and patients at risk for posttransplantation recurrence, and it may be associated with HCC recurrence after liver transplantation. © RSNA, 2017 Online supplemental material is available for this article.

Dicer1 functions as a haploinsufficient tumor suppressor.

While the global down-regulation of microRNAs (miRNAs) is a common feature of human tumors, its genetic basis is largely undefined. To explore this question, we analyzed the consequences of conditional Dicer1 mutation (Dicer1 "floxed" or Dicer1(fl)) on several mouse models of cancer. Here we show Dicer1 functions as a haploinsufficient tumor suppressor gene. Deletion of a single copy of Dicer1 in tumors from Dicer1(fl/+) animals led to reduced survival compared with controls. These tumors exhibited impaired miRNA processing but failed to lose the wild-type Dicer1 allele. Moreover, tumors from Dicer1(fl/fl) animals always maintained one functional Dicer1 allele. Consistent with selection against full loss of Dicer1 expression, enforced Dicer1 deletion caused inhibition of tumorigenesis. Analysis of human cancer genome copy number data reveals frequent deletion of DICER1. Importantly, however, the gene has not been reported to undergo homozygous deletion, suggesting that DICER1 is haploinsufficient in human cancer. These findings suggest Dicer1 may be an important haploinsufficient tumor suppressor gene and, furthermore, that other factors controlling miRNA biogenesis may also function in this manner.

Preoperative or postoperative radiotherapy versus surgery alone for retroperitoneal sarcoma: a case-control, propensity score-matched analysis of a nationwide clinical oncology database.

BACKGROUND: Recruitment into clinical trials for retroperitoneal sarcoma has been challenging, resulting in termination of the only randomised multicentre trial in the USA investigating perioperative radiotherapy. Nonetheless, use of radiotherapy for retroperitoneal sarcoma has increased over the past decade, substantiated primarily by its established role in extremity sarcoma. In this study, we used a nationwide clinical oncology database to separately compare overall survival for patients with retroperitoneal sarcoma who had surgery and preoperative radiotherapy or surgery and postoperative radiotherapy versus surgery alone. METHODS: We did two case-control, propensity score-matched analyses of the National Cancer Data Base, which included adult patients with retroperitoneal sarcoma who were diagnosed from 2003 to 2011. Patients were included if they had localised, primary retroperitoneal sarcoma. Patients were classified into three groups based on use of radiotherapy: preoperative radiotherapy, postoperative radiotherapy, and no radiotherapy (surgery alone). Patients were excluded if they received both preoperative radiotherapy and postoperative radiotherapy, or if they received intraoperative radiotherapy. Parallel propensity score-matched datasets were created for patients who received preoperative radiotherapy versus those who received no radiotherapy and for patients who received postoperative therapy versus those who received no radiotherapy. Propensity scores were calculated with logistic regression, with multiple imputation and backwards elimination, with a significance level to stay of 0·05. Matching was done with a nearest-neighbour algorithm and matched 1:2 for the preoperative radiotherapy dataset and 1:1 for the postoperative radiotherapy dataset. The primary objective of interest was overall survival for patients who received preoperative radiotherapy or postoperative radiotherapy compared with those who received no radiotherapy within the propensity score-matched datasets. FINDINGS: 9068 patients were included in this analysis: 563 in the preoperative radiotherapy group, 2215 in the postoperative radiotherapy group, and 6290 in the no radiotherapy group. Matching resulted in two comparison groups (preoperative radiotherapy vs no radiotherapy, and postoperative radiotherapy vs no radiotherapy) with negligible differences in all demographic, clinicopathological, and treatment-level variables. In the matched case-control analysis for preoperative radiotherapy median follow-up time was 42 months (IQR 27-70) for the preoperative radiotherapy group versus 43 months (25-64) for the no radiotherapy group; median overall survival was 110 months (95% CI 75-not estimable) versus 66 months (61-76), respectively. In the matched case-control analysis for postoperative radiotherapy median follow-up time was 54 months (IQR 32-79) for patients in the postoperative radiotherapy group and 47 months (26-72) for patients in the no radiotherapy group; median overall survival was 89 months (95% CI 79-100) versus 64 months (59-69), respectively. Both preoperative radiotherapy (HR 0·70, 95% CI 0·59-0·82; p<0·0001) and postoperative radiotherapy (HR 0·78, 0·71-0·85; p<0·0001) were significantly associated with improved overall survival compared with surgery alone. INTERPRETATION: To the best of our knowledge, this is the largest study to date of the effect of radiotherapy on overall survival in patients with retroperitoneal sarcoma. Radiotherapy was associated with improved overall survival compared with surgery alone when delivered as either preoperative radiotherapy or postoperative radiotherapy. Together with the results from the ongoing randomised EORTC trial (62092-22092; NCT01344018) investigating preoperative radiotherapy for retroperitoneal sarcoma pending, these data might provide additional support for the increasing use of radiotherapy for patients with retroperitoneal sarcoma undergoing surgical resection. FUNDING: Department of Surgery, Duke University School of Medicine.

Elevated Lung Shunt Fraction as a Prognostic Indicator for Disease Progression and Metastasis in Hepatocellular Carcinoma.

PURPOSE: To evaluate lung shunt fraction (LSF) as an early predictor for local disease progression or the development of metastatic disease. MATERIALS AND METHODS: Retrospective analysis was performed on 52 patients with hepatocellular carcinoma who underwent preradioembolization assessment, including the calculation of LSF. Comparison of preprocedural and postprocedural surveillance imaging was performed. Mean patient age was 67 years (range, 50-88 y), with a mean surveillance of 245 days (range, 24-871 d). Statistical analysis was conducted to assess the relationship between LSF and local disease progression or development of new metastatic disease. RESULTS: In patients in whom metastatic disease developed during routine surveillance, the mean LSF was almost double that in patients in whom no metastasis developed (18.3% vs 9.3%; P = .001). Patients with elevated LSFs were also more likely to show intrahepatic disease progression (15.6% vs 8.5%; P = .003). LSFs < 8% corresponded to negative predictive values of 74% for local disease progression and 95% for development of metastasis, signaling a better prognosis. Of pretreatment variables examined (age, sex, previous treatment with disease progression, lesion size, lesion number, LSF, α-fetoprotein level, and portal vein thrombus), only LSF was an independent predictor for new metastasis (odds ratio [OR] = 1.2; P = .01). LSF (OR = 1.2; P = .03) and progression after previous treatment (OR = 4.7; P = .04) were independent predictors for local progression. CONCLUSIONS: As local disease progression and metastatic disease were more likely to occur in patients with elevated LSFs, LSF may be the most sensitive predictor for local disease progression and new metastatic disease.

A Novel Imaging System Distinguishes Neoplastic from Normal Tissue During Resection of Soft Tissue Sarcomas and Mast Cell Tumors in Dogs.

OBJECTIVE: To assess the ability of a novel imaging system designed for intraoperative detection of residual cancer in tumor beds to distinguish neoplastic from normal tissue in dogs undergoing resection of soft tissue sarcoma (STS) and mast cell tumor (MCT). STUDY DESIGN: Non-randomized prospective clinical trial. ANIMALS: 12 dogs with STS and 7 dogs with MCT. METHODS: A fluorescent imaging agent that is activated by proteases in vivo was administered to the dogs 4-6 or 24-26 hours before tumor resection. During surgery, a handheld imaging device was used to measure fluorescence intensity within the cancerous portion of the resected specimen and determine an intensity threshold for subsequent identification of cancer. Selected areas within the resected specimen and tumor bed were then imaged, and biopsies (n=101) were obtained from areas that did or did not have a fluorescence intensity exceeding the threshold. Results of intraoperative fluorescence and histology were compared. RESULTS: The imaging system correctly distinguished cancer from normal tissue in 93/101 biopsies (92%). Using histology as the reference, the sensitivity and specificity of the imaging system for identification of cancer in biopsies were 92% and 92%, respectively. There were 10/19 (53%) dogs which exhibited transient facial erythema soon after injection of the imaging agent which responded to but was not consistently prevented by intravenous diphenhydramine. CONCLUSION: A fluorescence-based imaging system designed for intraoperative use can distinguish canine soft tissue sarcoma (STS) and mast cell tumor (MCT) tissue from normal tissue with a high degree of accuracy. The system has potential to assist surgeons in assessing the adequacy of tumor resections during surgery, potentially reducing the risk of local tumor recurrence. Although responsive to antihistamines, the risk of hypersensitivity needs to be considered in light of the potential benefits of this imaging system in dogs.