The MUC1-HIF-1α signaling axis regulates pancreatic cancer pathogenesis through polyamine metabolism remodeling.

Dysregulation of polyamine metabolism has been implicated in cancer initiation and progression; however, the mechanism of polyamine dysregulation in cancer is not fully understood. In this study, we investigated the role of MUC1, a mucin protein overexpressed in pancreatic cancer, in regulating polyamine metabolism. Utilizing pancreatic cancer patient data, we noted a positive correlation between MUC1 expression and the expression of key polyamine metabolism pathway genes. Functional studies revealed that knockdown of spermidine/spermine N1-acetyltransferase 1 (SAT1), a key enzyme involved in polyamine catabolism, attenuated the oncogenic functions of MUC1, including cell survival and proliferation. We further identified a regulatory axis whereby MUC1 stabilized hypoxia-inducible factor (HIF-1α), leading to increased SAT1 expression, which in turn induced carbon flux into the tricarboxylic acid cycle. MUC1-mediated stabilization of HIF-1α enhanced the promoter occupancy of the latter on SAT1 promoter and corresponding transcriptional activation of SAT1, which could be abrogated by pharmacological inhibition of HIF-1α or CRISPR/Cas9-mediated knockout of HIF1A. MUC1 knockdown caused a significant reduction in the levels of SAT1-generated metabolites, N1-acetylspermidine and N8-acetylspermidine. Given the known role of MUC1 in therapy resistance, we also investigated whether inhibiting SAT1 would enhance the efficacy of FOLFIRINOX chemotherapy. By utilizing organoid and orthotopic pancreatic cancer mouse models, we observed that targeting SAT1 with pentamidine improved the efficacy of FOLFIRINOX, suggesting that the combination may represent a promising therapeutic strategy against pancreatic cancer. This study provides insights into the interplay between MUC1 and polyamine metabolism, offering potential avenues for the development of treatments against pancreatic cancer.

Temporal analysis of melanogenesis identifies fatty acid metabolism as key skin pigment regulator.

Therapeutic methods to modulate skin pigmentation has important implications for skin cancer prevention and for treating cutaneous hyperpigmentary conditions. Towards defining new potential targets, we followed temporal dynamics of melanogenesis using a cell-autonomous pigmentation model. Our study elucidates 3 dominant phases of synchronized metabolic and transcriptional reprogramming. The melanogenic trigger is associated with high MITF levels along with rapid uptake of glucose. The transition to pigmented state is accompanied by increased glucose channelisation to anabolic pathways that support melanosome biogenesis. SREBF1-mediated up-regulation of fatty acid synthesis results in a transient accumulation of lipid droplets and enhancement of fatty acids oxidation through mitochondrial respiration. While this heightened bioenergetic activity is important to sustain melanogenesis, it impairs mitochondria lately, shifting the metabolism towards glycolysis. This recovery phase is accompanied by activation of the NRF2 detoxication pathway. Finally, we show that inhibitors of lipid metabolism can resolve hyperpigmentary conditions in a guinea pig UV-tanning model. Our study reveals rewiring of the metabolic circuit during melanogenesis, and fatty acid metabolism as a potential therapeutic target in a variety of cutaneous diseases manifesting hyperpigmentary phenotype.

Associations of stem cell markers CD44, CD24 and ALDH1A1 with mammographic breast density in women with benign breast biopsies.

BACKGROUND: We examined associations of CD44, CD24 and ALDH1A1 breast stem cell markers with mammographic breast density (MBD), a well-established breast cancer (BCa) risk factor. METHODS: We included 218 cancer-free women with biopsy-confirmed benign breast disease within the Nurses' Health Study (NHS) and NHSII. The data on BCa risk factors were obtained from biennial questionnaires. Immunohistochemistry (IHC) was done on tissue microarrays. For each core, the IHC expression was assessed using a semi-automated platform and expressed as percent of positively stained cells for each marker out of the total cell count. MBD was assessed with computer-assisted techniques. Generalised linear regression was used to examine the associations of each marker with square root-transformed percent density (PD), absolute dense and non-dense areas (NDA), adjusted for BCa risk factors. RESULTS: Stromal CD44 and ALDH1A1 expression was positively associated with PD (≥ 10% vs. <10% ß = 0.56, 95% confidence interval [CI] [0.06; 1.07] and ß = 0.81 [0.27; 1.34], respectively) and inversely associated with NDA (ß per 10% increase = -0.17 [-0.34; -0.01] and ß for ≥10% vs. <10% = -1.17 [-2.07; -0.28], respectively). Epithelial CD24 expression was inversely associated with PD (ß per 10% increase = -0.14 [-0.28; -0.01]. Stromal and epithelial CD24 expression was positively associated with NDA (ß per 10% increase = 0.35 [0.2 × 10-2; 0.70] and ß per 10% increase = 0.34 [0.11; 0.57], respectively). CONCLUSION: Expression of stem cell markers is associated with MBD.

Reproductive risk factors for breast cancer and association with novel breast density measurements among Hispanic, Black, and White women.

PURPOSE: There are differences in the distributions of breast cancer incidence and risk factors by race and ethnicity. Given the strong association between breast density and breast cancer, it is of interest describe racial and ethnic variation in the determinants of breast density. METHODS: We characterized racial and ethnic variation in reproductive history and several measures of breast density for Hispanic (n = 286), non-Hispanic Black (n = 255), and non-Hispanic White (n = 1694) women imaged at a single hospital. We quantified associations between reproductive factors and percent volumetric density (PVD), dense volume (DV), non-dense volume (NDV), and a novel measure of pixel intensity variation (V) using multivariable-adjusted linear regression, and tested for statistical heterogeneity by race and ethnicity. RESULTS: Reproductive factors most strongly associated with breast density were age at menarche, parity, and oral contraceptive use. Variation by race and ethnicity was most evident for the associations between reproductive factors and NDV (minimum p-heterogeneity:0.008) and V (minimum p-heterogeneity:0.004) and least evident for PVD (minimum p-heterogeneity:0.042) and DV (minimum p-heterogeneity:0.041). CONCLUSION: Reproductive choices, particularly those related to childbearing and oral contraceptive use, may contribute to racial and ethnic variation in breast density.

PTGES Expression Is Associated with Metabolic and Immune Reprogramming in Pancreatic Ductal Adenocarcinoma.

Metabolic reprogramming is an established hallmark of multiple cancers, including pancreatic cancer. Dysregulated metabolism is utilized by cancer cells for tumor progression, metastasis, immune microenvironment remodeling, and therapeutic resistance. Prostaglandin metabolites have been shown to be critical for inflammation and tumorigenesis. While the functional role of prostaglandin E2 metabolite has been extensively studied, there is a limited understanding of the PTGES enzyme in pancreatic cancer. Here, we investigated the relationship between expression of prostaglandin E synthase (PTGES) isoforms and the pathogenesis and regulation of pancreatic cancer. Our analysis identified higher expression of PTGES in pancreatic tumors compared to normal pancreatic tissues, suggesting an oncogenic function. Only PTGES1 expression was significantly correlated with worse prognosis of pancreatic cancer patients. Further, utilizing cancer genome atlas data, PTGES was found to be positively correlated with epithelial-mesenchymal transition, metabolic pathways, mucin oncogenic proteins, and immune pathways in cancer cells. PTGES expression was also correlated with higher mutational burden in key driver genes, such as TP53 and KRAS. Furthermore, our analysis indicated that the oncogenic pathway controlled by PTGES1 could be regulated via DNA methylation-dependent epigenetic mechanisms. Notably, the glycolysis pathway was positively correlated with PTGES and may fuel cancer cell growth. PTGES expression was also associated with downregulation of the MHC pathway and negatively correlated with CD8+ T cell activation markers. In summary, our study established an association of PTGES expression with pancreatic cancer metabolism and the immune microenvironment.

Metabolic Rewiring by Loss of Sirt5 Promotes Kras-Induced Pancreatic Cancer Progression.

BACKGROUND & AIMS: SIRT5 plays pleiotropic roles via post-translational modifications, serving as a tumor suppressor, or an oncogene, in different tumors. However, the role SIRT5 plays in the initiation and progression of pancreatic ductal adenocarcinoma (PDAC) remains unknown. METHODS: Published datasets and tissue arrays with SIRT5 staining were used to investigate the clinical relevance of SIRT5 in PDAC. Furthermore, to define the role of SIRT5 in the carcinogenesis of PDAC, we generated autochthonous mouse models with conditional Sirt5 knockout. Moreover, to examine the mechanistic role of SIRT5 in PDAC carcinogenesis, SIRT5 was knocked down in PDAC cell lines and organoids, followed by metabolomics and proteomics studies. A novel SIRT5 activator was used for therapeutic studies in organoids and patient-derived xenografts. RESULTS: SIRT5 expression negatively regulated tumor cell proliferation and correlated with a favorable prognosis in patients with PDAC. Genetic ablation of Sirt5 in PDAC mouse models promoted acinar-to-ductal metaplasia, precursor lesions, and pancreatic tumorigenesis, resulting in poor survival. Mechanistically, SIRT5 loss enhanced glutamine and glutathione metabolism via acetylation-mediated activation of GOT1. A selective SIRT5 activator, MC3138, phenocopied the effects of SIRT5 overexpression and exhibited antitumor effects on human PDAC cells. MC3138 also diminished nucleotide pools, sensitizing human PDAC cell lines, organoids, and patient-derived xenografts to gemcitabine. CONCLUSIONS: Collectively, we identify SIRT5 as a key tumor suppressor in PDAC, whose loss promotes tumorigenesis through increased noncanonic use of glutamine via GOT1, and that SIRT5 activation is a novel therapeutic strategy to target PDAC.

Associations of reproductive breast cancer risk factors with breast tissue composition.

BACKGROUND: We investigated the associations of reproductive factors with the percentage of epithelium, stroma, and fat tissue in benign breast biopsy samples. METHODS: This study included 983 cancer-free women with biopsy-confirmed benign breast disease (BBD) within the Nurses' Health Study and Nurses' Health Study II cohorts. The percentage of each tissue type (epithelium, stroma, and fat) was measured on whole-section images with a deep-learning technique. All tissue measures were log-transformed in all the analyses to improve normality. The data on reproductive variables and other breast cancer risk factors were obtained from biennial questionnaires. Generalized linear regression was used to examine the associations of reproductive factors with the percentage of tissue types, while adjusting for known breast cancer risk factors. RESULTS: As compared to parous women, nulliparous women had a smaller percentage of epithelium (ß = - 0.26, 95% confidence interval [CI] - 0.41, - 0.11) and fat (ß = - 0.34, 95% CI - 0.54, - 0.13) and a greater percentage of stroma (ß = 0.04, 95% CI 0.01, 0.08). Among parous women, the number of children was inversely associated with the percentage of stroma (ß per child = - 0.01, 95% CI - 0.02, - 0.00). The duration of breastfeeding of ≥ 24 months was associated with a reduced proportion of fat (ß = - 0.30, 95% CI - 0.54, - 0.06; p-trend = 0.04). In a separate analysis restricted to premenopausal women, older age at first birth was associated with a greater proportion of epithelium and a smaller proportion of stroma. CONCLUSIONS: Our findings suggest that being nulliparous as well as having a fewer number of children (both positively associated with breast cancer risk) is associated with a smaller proportion of epithelium and a greater proportion of stroma, potentially suggesting the importance of epithelial-stromal interactions. Future studies are warranted to confirm our findings and to elucidate the underlying biological mechanisms.

The Molecular Mechanism Underlying Recruitment and Insertion of Lipid-Anchored LC3 Protein into Membranes.

Lipid modification of cytoplasmic proteins initiates membrane engagement that triggers diverse cellular processes. Despite the abundance of lipidated proteins in the human proteome, the key determinants underlying membrane recognition and insertion are poorly understood. Here, we define the course of spontaneous membrane insertion of LC3 protein modified with phosphatidylethanolamine using multiple coarse-grain simulations. The partitioning of the lipid anchor chains proceeds through a concerted process, with its two acyl chains inserting one after the other. Concurrently, a conformational rearrangement involving the α-helix III of LC3, especially in the three basic residues Lys65, Arg68, and Arg69, ensures stable insertion of the phosphatidylethanolamine anchor into membranes. Mutational studies validate the crucial role of these residues, and further live-cell imaging analysis shows a substantial reduction in the formation of autophagic vesicles for the mutant proteins. Our study captures the process of water-favored LC3 protein recruitment to the membrane and thus opens, to our knowledge, new avenues to explore the cellular dynamics underlying vesicular trafficking.

Associations of reproductive breast cancer risk factors with expression of stem cell markers in benign breast tissue.

Background: We investigated the associations of reproductive factors known to influence breast cancer risk with the expression of breast stem cell markers CD44, CD24, and ALDH1A1 in benign breast biopsy samples. Methods: We included 439 cancer-free women with biopsy-confirmed benign breast disease within the Nurses' Health Study (NHS) and NHSII. The data on reproductive and other breast cancer risk factors were obtained from biennial questionnaires. Immunohistochemistry (IHC) was performed on tissue microarrays. For each core, the IHC expression was assessed using a semi-automated platform and expressed as % of cells that stained positive for a specific marker out of the total cell count. Generalized linear regression was used to examine the associations of reproductive factors with a log-transformed expression of each marker (in epithelium and stroma), adjusted for other breast cancer risk factors. Results: In multivariate analysis, the time between menarche and age at first birth was inversely associated with CD44 in epithelium (ß per 5 years = -0.38, 95% CI -0.69; -0.06). Age at first birth and the time between menarche and age at first birth were inversely associated with ALDH1A1 (stroma: ß per 5 years = -0.43, 95% CI -0.76; -0.10 and ß = -0.47, 95% CI -0.79; -0.15, respectively; epithelium: ß = -0.15, 95% CI -0.30; -0.01 and ß = -0.17, 95% CI -0.30; -0.03, respectively). Time since last pregnancy was inversely associated with stromal ALDH1A1 (ß per 5 years = -0.55, 95% CI -0.98; -0.11). No associations were found for CD24. The observed associations were similar in premenopausal women. In postmenopausal women, lifetime duration of breastfeeding was inversely associated with stromal ALDH1A1 expression (ß for ≥24 vs. 0 to <1 months = -2.24, 95% CI 3.96; -0.51, p-trend = 0.01). Conclusion: Early-life reproductive factors may influence CD44 and ALDH1A1 expression in benign breast tissue.

Associations of Early-Life and Adult Anthropometric Measures with the Expression of Stem Cell Markers CD44, CD24, and ALDH1A1 in Women with Benign Breast Biopsies.

BACKGROUND: According to the stem cell hypothesis, breast carcinogenesis may be related to the breast stem cell pool size. However, little is known about associations of breast cancer risk factors, such as anthropometric measures, with the expression of stem cell markers in noncancerous breast tissue. METHODS: The analysis included 414 women with biopsy-confirmed benign breast disease in the Nurses' Health Study and Nurses' Health Study II. Birthweight, weight at age 18, current weight, and current height were reported via self-administered questionnaires. IHC staining of stem cell markers (CD44, CD24, and aldehyde dehydrogenase family 1 member A1) in histopathologically normal epithelial and stromal breast tissue was quantified using an automated computational image analysis system. Linear regression was used to examine the associations of early-life and adult anthropometric measures with log-transformed stem cell marker expression, adjusting for potential confounders. RESULTS: Birthweight [≥10.0 vs. <5.5 lbs: ß (95% confidence interval) = 4.29 (1.02, 7.56); P trend = 0.001 in the stroma] and adult height [≥67.0 vs. <63.0 inch: 0.86 (0.14, 1.58); P trend = 0.02 in the epithelium and stroma combined] were positively associated with CD44 expression. Childhood body fatness was inversely associated (P trend = 0.03) whereas adult height was positively associated with CD24 expression in combined stroma and epithelium (P trend = 0.03). CONCLUSIONS: Our data suggest that anthropometric measures, such as birthweight, adult height, and childhood body fatness, may be associated with the stem cell expression among women with benign breast disease. IMPACT: Anthropometric measures, such as birthweight, height, and childhood body fatness, may have long-term impacts on stem cell population in the breast.

CD24 negativity reprograms mitochondrial metabolism to PPARα and NF-κB-driven fatty acid ß-oxidation in triple-negative breast cancer.

CD24 is a well-characterized breast cancer (BC) stem cell (BCSC) marker. Primary breast tumor cells having CD24-negativity together with CD44-positivity is known to maintain high metastatic potential. However, the functional role of CD24 gene in triple-negative BC (TNBC), an aggressive subtype of BC, is not well understood. While the significance of CD24 in regulating immune pathways is well recognized in previous studies, the significance of CD24 low expression in onco-signaling and metabolic rewiring is largely unknown. Using CD24 knock-down and over-expression TNBC models, our in vitro and in vivo analysis suggest that CD24 is a tumor suppressor in metastatic TNBC. Comprehensive in silico gene expression analysis of breast tumors followed by lipidomic and metabolomic analyses of CD24-modulated cells revealed that CD24 negativity induces mitochondrial oxidative phosphorylation and reprograms TNBC metabolism toward the fatty acid beta-oxidation (FAO) pathway. CD24 silencing activates PPARα-mediated regulation of FAO in TNBC cells. Further analysis using reverse-phase protein array and its validation using CD24-modulated TNBC cells and xenograft models nominated CD24-NF-κB-CPT1A signaling pathway as the central regulatory mechanism of CD24-mediated FAO activity. Overall, our study proposes a novel role of CD24 in metabolic reprogramming that can open new avenues for the treatment strategies for patients with metastatic TNBC.

Vitamin B6 Competition in the Tumor Microenvironment Hampers Antitumor Functions of NK Cells.

Nutritional factors play crucial roles in immune responses. The tumor-caused nutritional deficiencies are known to affect antitumor immunity. Here, we demonstrate that pancreatic ductal adenocarcinoma (PDAC) cells can suppress NK-cell cytotoxicity by restricting the accessibility of vitamin B6 (VB6). PDAC cells actively consume VB6 to support one-carbon metabolism, and thus tumor cell growth, causing VB6 deprivation in the tumor microenvironment. In comparison, NK cells require VB6 for intracellular glycogen breakdown, which serves as a critical energy source for NK-cell activation. VB6 supplementation in combination with one-carbon metabolism blockage effectively diminishes tumor burden in vivo. Our results expand the understanding of the critical role of micronutrients in regulating cancer progression and antitumor immunity, and open new avenues for developing novel therapeutic strategies against PDAC. SIGNIFICANCE: The nutrient competition among the different tumor microenvironment components drives tumor growth, immune tolerance, and therapeutic resistance. PDAC cells demand a high amount of VB6, thus competitively causing NK-cell dysfunction. Supplying VB6 with blocking VB6-dependent one-carbon metabolism amplifies the NK-cell antitumor immunity and inhibits tumor growth in PDAC models. This article is featured in Selected Articles from This Issue, p. 5.

Cancer-associated fibroblast-derived acetate promotes pancreatic cancer development by altering polyamine metabolism via the ACSS2-SP1-SAT1 axis.

The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP-seq and RNA-seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2-SP1-SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2-SP1-SAT1 axis.

Associations of stem cell markers in benign breast tissue with subsequent breast cancer risk.

We examined associations of stem cell markers CD44, CD24, and ALDH1A1 in benign breast biopsy samples with subsequent breast cancer (BCa) risk and explored if these associations were mediated by mammographic breast density (MBD). We included 101 BCa cases/375 controls, all with previous biopsy-confirmed benign breast disease (BBD) within the Nurses' Health Study (NHS) and NHSII. The data on BCa risk factors were obtained from biennial questionnaires. MBD was assessed with computer-assisted techniques. Immunohistochemistry (IHC) was done on BBD tissue microarrays. For each core, the IHC expression was assessed using a semi-automated method, and expressed as % of cells that stained positive for a specific marker out of the total cell count. Logistic regression was used to examine the associations of each marker's expression of each (in epithelium and stroma) with BCa risk, adjusted for risk factors. Stromal CD44 expression was inversely associated with BCa risk (OR for ≥10% vs. <10%=0.58, 95% CI 0.34, 1.00). Combined stromal + epithelial CD24 expression was inversely associated with BCa risk (>50% vs. 0-10% OR=0.17, 95% CI 0.04-0.81, p-trend =0.03). Stromal CD24 and ALDH1A1 as well as epithelial expression of any of the three markers were not associated with BCa risk. In a smaller subset of women with available MBD, these observed associations did not appear to be mediated by MBD. Our findings suggest inverse associations of CD44 in stroma and combined stromal + epithelial CD24 with BCa risk. Future studies are warranted to confirm our findings and to examine these associations by BBD subtype.

Reliability of CD44, CD24, and ALDH1A1 immunohistochemical staining: Pathologist assessment compared to quantitative image analysis.

Background: The data on the expression of stem cell markers CD44, CD24, and ALDH1A1 in the breast tissue of cancer-free women is very limited and no previous studies have explored the agreement between pathologist and computational assessments of these markers. We compared the immunohistochemical (IHC) expression assessment for CD44, CD24, and ALDH1A1 by an expert pathologist with the automated image analysis results and assessed the homogeneity of the markers across multiple cores pertaining to each woman. Methods: We included 81 cancer-free women (399 cores) with biopsy-confirmed benign breast disease in the Nurses' Health Study (NHS) and NHSII cohorts. IHC was conducted with commercial antibodies [CD44 (Dako, Santa Clara, CA, USA) 1:25 dilution; CD24 (Invitrogen, Waltham, MA, USA) 1:200 dilution and ALDH1A1 (Abcam, Cambridge, United Kingdom) 1:300 dilution]. For each core, the percent positivity was quantified by the pathologist and Definiens Tissue Studio. Correlations between pathologist and computational scores were evaluated with Spearman correlation (for categorical positivity: 0, >0-<1, 1-10, >10-50, and >50%) and sensitivity/specificity (for binary positivity defined with 1 and 10% cut-offs), using the pathologist scores as the gold standard. Expression homogeneity was examined with intra-class correlation (ICC). Analyses were stratified by core [normal terminal duct-lobular units (TDLUs), benign lesions] and tissue type (epithelium, stroma). Results: Spearman correlation between pathologist and Definiens ranged between 0.40-0.64 for stroma and 0.66-0.68 for epithelium in normal TDLUs cores and between 0.24-0.60 for stroma and 0.61-0.64 for epithelium in benign lesions. For stroma, sensitivity and specificity ranged between 0.92-0.95 and 0.24-0.60, respectively, with 1% cut-off and between 0.43-0.88 and 0.73-0.85, respectively, with 10% cut-off. For epithelium, 10% cut-off resulted in better estimates for both sensitivity and specificity. ICC between the cores was strongest for CD44 for both stroma and epithelium in normal TDLUs cores and benign lesions (range 0.74-0.80). ICC for CD24 and ALDH1A ranged between 0.42-0.63 and 0.44-0.55, respectively. Conclusion: Our findings show that computational assessments for CD44, CD24, and ALDH1A1 exhibit variable correlations with manual assessment. These findings support the use of computational platforms for IHC evaluation of stem cell markers in large-scale epidemiologic studies. Pilot studies maybe also needed to determine appropriate cut-offs for defining staining positivity.

MnTE-2-PyP protects fibroblast mitochondria from hyperglycemia and radiation exposure.

Radiation is a common anticancer therapy for prostate cancer, which transforms tumor-associated normal fibroblasts to myofibroblasts, resulting in fibrosis. Oxidative stress caused by radiation-mediated mitochondrial damage is one of the major contributors to fibrosis. As diabetics are oxidatively stressed, radiation-mediated reactive oxygen species cause severe treatment failure, treatment-related side effects, and significantly reduced survival for diabetic prostate cancer patients as compared to non-diabetic prostate cancer patients. Hyperglycemia and enhanced mitochondrial damage significantly contribute to oxidative damage and disease progression after radiation therapy among diabetic prostate cancer patients. Therefore, reduction of mitochondrial damage in normal prostate fibroblasts after radiation should improve the overall clinical state of diabetic prostate cancer patients. We previously reported that MnTE-2-PyP, a manganese porphyrin, reduces oxidative damage in irradiated hyperglycemic prostate fibroblasts by scavenging superoxide and activating NRF2. In the current study, we have investigated the potential role of MnTE-2-PyP to protect mitochondrial health in irradiated hyperglycemic prostate fibroblasts. This study revealed that hyperglycemia and radiation increased mitochondrial ROS via blocking the mitochondrial electron transport chain, altered mitochondrial dynamics, and reduced mitochondrial biogenesis. Increased mitochondrial damage preceeded an increase in myofibroblast differentiation. MnTE-2-PyP reduced myofibroblast differentiation, improved mitochondrial health by releasing the block on the mitochondrial electron transport chain, enhanced ATP production efficiency, and restored mitochondrial dynamics and metabolism in the irradiated-hyperglycemic prostate fibroblasts. Therefore, we are proposing that one of the mechanisms that MnTE-2-PyP protects prostate fibroblasts from irradiation and hyperglycemia-mediated damage is by protecting the mitochondrial health in diabetic prostate cancer patients.

Exposure to natural vegetation in relation to mammographic density in a Massachusetts-based clinical cohort.

Inverse associations between natural vegetation exposure (i.e., greenness) and breast cancer risk have been reported; however, it remains unknown whether greenness affects breast tissue development or operates through other mechanisms (e.g., body mass index [BMI] or physical activity). We examined the association between greenness and mammographic density-a strong breast cancer risk factor-to determine whether greenness influences breast tissue composition independent of lifestyle factors. Methods: Women (n = 2,318) without a history of breast cancer underwent mammographic screening at Brigham and Women's Hospital in Boston, Massachusetts, from 2006 to 2014. Normalized Difference Vegetation Index (NDVI) satellite data at 1-km2 resolution were used to estimate greenness at participants' residential address 1, 3, and 5 years before mammogram. We used multivariable linear regression to estimate differences in log-transformed volumetric mammographic density measures and 95% confidence intervals (CIs) for each 0.1 unit increase in NDVI. Results: Five-year annual average NDVI was not associated with percent mammographic density in premenopausal (ß = -0.01; 95% CI = -0.03, 0.02; P = 0.58) and postmenopausal women (ß = -0.02; 95% CI = -0.04, 0.01; P = 0.18). Results were similar for 1-year and 3-year NDVI measures and in models including potential mediators of BMI and physical activity. There were also no associations between greenness and dense volume and nondense volume. Conclusions: Greenness exposures were not associated with mammographic density. Impact: Prior observations of a protective association between greenness and breast cancer may not be driven by differences in breast tissue composition, as measured by mammographic density, but rather other mechanisms.

CD73 induces GM-CSF/MDSC-mediated suppression of T cells to accelerate pancreatic cancer pathogenesis.

Metabolic alterations regulate cancer aggressiveness and immune responses. Given the poor response of pancreatic ductal adenocarcinoma (PDAC) to conventional immunotherapies, we investigated the link between metabolic alterations and immunosuppression. Our metabolic enzyme screen indicated that elevated expression of CD73, an ecto-5'-nucleotidase that generates adenosine, correlates with increased aggressiveness. Correspondingly, we observed increased interstitial adenosine levels in tumors from spontaneous PDAC mouse models. Diminishing CD73 by genetic manipulations ablated in vivo tumor growth, and decreased myeloid-derived suppressor cells (MDSC) in orthotopic mouse models of PDAC. A high-throughput cytokine profiling demonstrated decreased GM-CSF in mice implanted with CD73 knockdowns. Furthermore, we noted increased IFN-γ expression by intratumoral CD4+ and CD8+ T cells in pancreatic tumors with CD73 knockdowns. Depletion of CD4+ T cells, but not CD8+ T cells abrogated the beneficial effects of decreased CD73. We also observed that splenic MDSCs from Nt5e knockdown tumor-bearing mice were incompetent in suppressing T cell activation in the ex vivo assays. Replenishing GM-CSF restored tumor growth in Nt5e knockout tumors, which was reverted by MDSC depletion. Finally, anti-CD73 antibody treatment significantly improved gemcitabine efficacy in orthotopic models. Thus, targeting the adenosine axis presents a novel therapeutic opportunity for improving the anti-tumoral immune response against PDAC.

Automated percent mammographic density, mammographic texture variation, and risk of breast cancer: a nested case-control study.

Percent mammographic density (PMD) is a strong breast cancer risk factor, however, other mammographic features, such as V, the standard deviation (SD) of pixel intensity, may be associated with risk. We assessed whether PMD, automated PMD (APD), and V, yielded independent associations with breast cancer risk. We included 1900 breast cancer cases and 3921 matched controls from the Nurses' Health Study (NHS) and the NHSII. Using digitized film mammograms, we estimated PMD using a computer-assisted thresholding technique. APD and V were determined using an automated computer algorithm. We used logistic regression to generate odds ratios (ORs) and 95% confidence intervals (CIs). Median time from mammogram to diagnosis was 4.1 years (interquartile range: 1.6-6.8 years). PMD (OR per SD:1.52, 95% CI: 1.42, 1.63), APD (OR per SD:1.32, 95% CI: 1.24, 1.41), and V (OR per SD:1.32, 95% CI: 1.24, 1.40) were positively associated with breast cancer risk. Associations for APD were attenuated but remained statistically significant after mutual adjustment for PMD or V. Women in the highest quartile of both APD and V (OR vs Q1/Q1: 2.49, 95% CI: 2.02, 3.06), or PMD and V (OR vs Q1/Q1: 3.57, 95% CI: 2.79, 4.58) had increased breast cancer risk. An automated method of PMD assessment is feasible and yields similar, but somewhat weaker, estimates to a manual measure. PMD, APD and V are each independently, positively associated with breast cancer risk. Women with dense breasts and greater texture variation are at the highest relative risk of breast cancer.

Early-Life and Adult Adiposity, Adult Height, and Benign Breast Tissue Composition.

BACKGROUND: Early-life and adult anthropometrics are associated with breast density and breast cancer risk. However, little is known about whether these factors also influence breast tissue composition beyond what is captured by breast density among women with benign breast disease (BBD). METHODS: This analysis included 788 controls from a nested case-control study of breast cancer within the Nurses' Health Study BBD subcohorts. Body fatness at ages 5 and 10 years was recalled using a 9-level pictogram. Weight at age 18, current weight, and height were reported via questionnaires. A deep-learning image analysis was used to quantify the percentages of epithelial, fibrous stromal, and adipose tissue areas within BBD slides. We performed linear mixed models to estimate beta coefficients (ß) and 95% confidence intervals (CI) for the relationships between anthropometrics and the log-transformed percentages of individual tissue type, adjusting for confounders. RESULTS: Childhood body fatness (level ≥ 4.5 vs. 1), BMI at age 18 (≥23 vs. <19 kg/m2), and current adult BMI (≥30 vs. <21 kg/m2) were associated with higher proportions of adipose tissue [ß (95% CI) = 0.34 (0.03, 0.65), 0.19 (-0.04-0.42), 0.40 (0.12, 0.68), respectively] and lower proportions of fibrous stromal tissue [-0.05 (-0.10, 0.002), -0.03 (-0.07, 0.003), -0.12 (-0.16, -0.07), respectively] during adulthood (all P trend < 0.04). BMI at age 18 was also inversely associated with epithelial tissue (P trend = 0.03). Adult height was not associated with any of the individual tissue types. CONCLUSIONS: Our data suggest that body fatness has long-term impacts on breast tissue composition. IMPACT: This study contributes to our understanding of the link between body fatness and breast cancer risk.See related commentary by Oskar et al., p. 590.