Solid tumor growth and metastasis require the interaction of tumor cells with the surrounding tissue, leading to a view of tumors as tissue-level phenomena rather than exclusively cell-intrinsic anomalies. Due to the ubiquitous nature of adipose tissue, many types of solid tumors grow in proximate or direct contact with adipocytes and adipose-associated stromal and vascular components, such as fibroblasts and other connective tissue cells, stem and progenitor cells, endothelial cells, innate and adaptive immune cells, and extracellular signaling and matrix components. Excess adiposity in obesity both increases risk of cancer development and negatively influences prognosis in several cancer types, in part due to interaction with adipose tissue cell populations. Herein, we review the cellular and noncellular constituents of the adipose “organ,” and discuss the mechanisms by which these varied microenvironmental components contribute to tumor development, with special emphasis on obesity. Due to the prevalence of breast and prostate cancers in the United States, their close anatomical proximity to adipose tissue depots, and their complex epidemiologic associations with obesity, we particularly highlight research addressing the contribution of adipose tissue to the initiation and progression of these cancer types. Obesity dramatically modifies the adipose tissue microenvironment in numerous ways, including induction of fibrosis and angiogenesis, increased stem cell abundance, and expansion of proinflammatory immune cells. As many of these changes also resemble shifts observed within the tumor microenvironment, proximity to adipose tissue may present a hospitable environment to developing tumors, providing a critical link between adiposity and tumorigenesis.

Macrophages (MFs) are heterogeneous and metabolically flexible, with metabolism strongly affecting immune activation. A classic response to proinflammatory activation is increased flux through glycolysis with a downregulation of oxidative metabolism, whereas alternative activation is primarily oxidative, which begs the question of whether targeting glucose metabolism is a viable approach to control MF activation. We created a murine model of myeloid-specific glucose transporter GLUT1 (Slc2a1) deletion. Bone marrow-derived MFs (BMDM) from Slc2a1 M2/2 mice failed to uptake glucose and demonstrated reduced glycolysis and pentose phosphate pathway activity. Activated BMDMs displayed elevated metabolism of oleate and glutamine, yet maximal respiratory capacity was blunted in MF lacking GLUT1, demonstrating an incomplete metabolic reprogramming. Slc2a1 M2/2 BMDMs displayed a mixed inflammatory phenotype with reductions of the classically activated pro-and anti-inflammatory markers, yet less oxidative stress. Slc2a1 M2/2 BMDMs had reduced proinflammatory metabolites, whereas metabolites indicative of alternative activation-such as ornithine and polyamines-were greatly elevated in the absence of GLUT1. Adipose tissue MFs of lean Slc2a1 M2/2 mice had increased alternative M2-like activation marker mannose receptor CD206, yet lack of GLUT1 was not a critical mediator in the development of obesity-associated metabolic dysregulation. However, Ldlr 2/2 mice lacking myeloid GLUT1 developed unstable atherosclerotic lesions. Defective phagocytic capacity in Slc2a1 M2/2 BMDMs may have contributed to unstable atheroma formation. Together, our findings suggest that although lack of GLUT1 blunted glycolysis and the pentose phosphate pathway, MF were metabolically flexible enough that inflammatory cytokine release was not dramatically regulated, yet phagocytic defects hindered MF function in chronic diseases.

Osteosarcoma (OS) is the most common primary malignancy of the bone that predominantly affects children and adolescents. Hippo pathway is a crucial regulator of organ size and tumorigenesis. However, how Hippo pathway regulates the occurrence of osteosarcoma is largely unknown. Here, we reported the regulator of G protein signaling protein 12 (RGS12) is a novel Hippo pathway regulator and tumor suppressor of osteosarcoma. Depletion of Rgs12 promotes osteosarcoma progression and lung metastasis in an orthotopic xenograft mouse model. Our data showed that knockdown of RGS12 upregulates Ezrin expression through promoting the GNA12/13-RhoA-YAP pathway. Moreover, RGS12 negatively regulates the transcriptional activity of YAP/TEAD1 complex through its PDZ domain function to inhibit the expression and function of the osteosarcoma marker Ezrin. PDZ domain peptides of RGS12 can inhibit the development of intratibial tumor and lung metastases. Collectively, this study identifies the RGS12 is a novel tumor suppressor in osteosarcoma through inhibiting YAP-TEAD1-Ezrin signaling pathway and provides a proof of principle that targeting RGS12 may be a therapeutic strategy for osteosarcoma.

The ability to assess toxicant exposures of 3D in vitro mammary models that recapitulate the tissue microenvironment can aid in our understanding of environmental exposure risk over time. Longitudinal studies of 3D model systems, however, are cumbersome and suffer from a lack of high-throughput toxicological assays. In this study, we establish a noninvasive and label-free optical coherence tomography (OCT)-based imaging platform for tracking exposure-response relationships in 3D human mammary epithelial organoid models. The OCT-based assay includes metrics that quantify organoid intracellular kinetic energy and cross-sectional area (CSA). We compare the results to those obtained using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) mitochondrial dye conversion assay. Both estrogen receptor (ER)-positive (MCF7) and ER-negative (MCF10DCIS.com) breast cell lines were studied, beginning one hour after exposure and continuing for several days. Six days of exposure to 17β-estradiol or the selective ER modulator 4-hydroxytamoxifen respectively increased or decreased MCF7 organoid CSA (p < .01), consistent with the role of estrogen signaling in ER-positive mammary epithelial cell proliferation. We also observed a significant decrease in the intracellular kinetic energy of MCF10DCIS.com organoids after 24 h of exposure to doxorubicin, a cytotoxic intercalating agent that causes DNA double-strand breaks (p < .01). MTT-based metabolic activity of MCF10DCIS.com organoids after 48 h of doxorubicin exposure decreased with dose in a similar manner as OCT-based energy metrics. These results demonstrate the feasibility of an OCT-based assay to quantify mammary epithelial cell toxicant response in vitro, noninvasively, longitudinally, and in the context of tissue microenvironments, providing a new high-throughput screening tool for toxicological studies.

Background: An understanding of how the mammary gland responds to toxicant and drug exposures can shed light on mechanisms of breast cancer initiation/progression and therapeutic effectiveness, respectively.In this study, we employed noninvasive, label-free and high-throughput optical coherence tomography speckle fluctuation spectroscopy (OCT-SFS) to track exposure-response relationships in three-dimensional (3D) mammary epithelial organoid models. Methods: OCT-SFS is sensitive to relatively high speed (~0.16-8 µm/min) motions of subcellular light scattering components occurring over short (~2-114 s) time scales, termed "intracellular motility." In this study, OCT speckle fluctuation spectra are quantified by two metrics: the intracellular motility amplitude, M, and frequency-dependent motility roll-off, α. OCT-SFS was performed on human mammary organoid models comprised of pre-malignant MCF10DCIS.com cells or MCF7 adenocarcinoma cells over 6 days of exposure to either a microtubule inhibitor (Paclitaxel, Taxol) or a myosin II inhibitor (Blebbistatin). Raw values of α and M were normalized to a dynamic range corresponding to fixed (0%) and live/homeostatic (100%) organoids for each cell line.Results: In this work, we observed a significant decrease in both M and α of MCF10DCIS.com organoids after 24 hours of exposure to Taxol (P<0.001), and a significant decrease only in α for MCF7 organoids after 48 hours of exposure (P<0.0001). We also observed a significant decrease in both M and α of MCF7 organoids at the longest exposure time of 6 days to Blebbistatin (P<0.0001), and a significant decrease only in M for MCF10DCIS.com organoids after 24 hours of exposure (P<0.01).Conclusions: OCT-SFS revealed cell line-specific response patterns, in terms of intracellular motility, to different motility suppression mechanisms. This provides a foundation for future OCT-SFS studies of longitudinal responses of the mammary gland in toxicology and drug research.

Mutations in tumor suppressor TP53 have been inconsistently linked to breast cancer risk factors and survival. Immunohistochemistry (IHC) staining, a primary clinical means of TP53 mutation determination, only detects mutations that facilitate protein accumulation (e.g., missense mutations). RNA-based pathway methods capture functional status and may aid in understanding the role of TP53 function in racial disparities of breast cancer. TP53 status was assessed among invasive breast cancer cases from the Carolina Breast Cancer Study (CBCS) (2008–2013) using IHC and an established RNA-based TP53 signature (CBCS and The Cancer Genome Atlas (TCGA)). Frequency of TP53 status (IHC, RNA-based) was estimated in association with tumor characteristics, PAM50 intrinsic subtype, age, and race using relative frequency differences (RFDs) and 95% confidence intervals (95% CI) as the measure of association. Approximately 60% of basal-like tumors were TP53 protein positive (IHC), while nearly 100% were TP53 mutant-like (RNA). Luminal A tumors had low frequency of TP53 positivity (IHC: 7.9%) and mutant-like status (RNA: 1.7%). Mutant-like TP53 (RNA) was strongly associated with age ≤50 years, high tumor grade, advanced stage of disease, large tumor size, and basal-like and HER2 intrinsic subtypes. Black race was strongly associated with TP53 mutant-like status (RNA) (RFD: 24.8%, 95% CI: 20.5, 29.0) even after adjusting for age, grade, stage (RFD: 11.3%; 95% CI: 7.6, 15.0). Associations were attenuated and non-significant when measured by IHC. IHC-based TP53 status is an insensitive measurement of TP53 functional status. RNA-based methods suggest a role for TP53 in tumor prognostic features and racial disparities.

◥High-grade sarcomas are metastatic and pose a serious threat to patient survival. Undifferentiated pleomorphic sarcoma (UPS) is a particularly dangerous and relatively common sarcoma subtype diagnosed in adults. UPS contains large quantities of extracellular matrix (ECM) including hyaluronic acid (HA), which is linked to metastatic potential. Consistent with these observations, expression of the HA receptor, hyaluronan-mediated motility receptor (HMMR/RHAMM), is tightly controlled in normal tissues and upregulated in UPS. Moreover, HMMR expression correlates with poor clinical outcome in these patients. Deregulation of the tumorsuppressive Hippo pathway is also linked to poor outcome in these patients. YAP1, the transcriptional regulator and central effector of Hippo pathway, is aberrantly stabilized in UPS and was recently shown to control RHAMM expression in breast cancer cells. Interestingly, both YAP1 and RHAMM are linked to TGFb signaling. Therefore, we investigated crosstalk between YAP1 and TGFb resulting in enhanced RHAMM-mediated cell migration and invasion. We observed that HMMR expression is under the control of both YAP1 and TGFb and can be effectively targeted with smallmolecule approaches that inhibit these pathways. Furthermore, we found that RHAMM expression promotes tumor cell proliferation and migration/invasion. To test these observations in a robust and quantifiable in vivo system, we developed a zebrafish xenograft assay of metastasis, which is complimentary to our murine studies. Importantly, pharmacologic inhibition of the TGFb-YAP1-RHAMM axis prevents vascular migration of tumor cells to distant sites.Implications: These studies reveal key metastatic signaling mechanisms and highlight potential approaches to prevent metastatic dissemination in UPS.YAP1 and TGFb cooperatively enhance proliferation and migration/invasion of UPS and fibrosarcomas.

Hyperbaric oxygen therapy (HBOT) is used for a number of applications, including the treatment of diabetic foot ulcers and CO poisoning. However, we and others have shown that HBOT can mobilize cellular antioxidant defenses, suggesting that it may also be useful under circumstances in which tissue protection from oxidative damage is desired. To test the protective properties of hyperbaric oxygen (HBO) on a tissue level, we evaluated the ability of a preconditioning treatment regimen to protect cutaneous tissue from UV-A-induced oxidative damage. Three groups of hairless SKH1-E mice were exposed to UV-A 3 days per week for 22 weeks, with two of these groups receiving an HBO pretreatment either two or four times per week. UV-A exposure increased apoptosis and proliferation of the skin tissue, indicating elevated levels of epithelial damage and repair. Pretreatment with HBO significantly reduced UV-A-induced apoptosis and proliferation. A morphometric analysis of microscopic tissue folds also showed a significant increase in skin creasing following UV-A exposure, which was prevented by HBO pretreatment. Likewise, skin elasticity was found to be greatest in the group treated with HBO four times per week. The effects of HBO were also apparent systemically as reductions in caspase-3 activity and expression were observed in the liver. Our findings support a protective function of HBO pretreatment from a direct oxidative challenge of UV-A to skin tissue. Similar protection of other tissues may likewise be achievable.