Glioblastoma multiforme (GBM) is the most common and lethal cancer of the adult brain, remaining incurable with a median survival time of only 15 months. In an effort to identify new targets for GBM diagnostics and therapeutics, recent studies have focused on molecular phenotyping of GBM subtypes. This has resulted in mounting interest in microRNAs (miRNAs) due to their regulatory capacities in both normal development and in pathological conditions such as cancer. miRNAs have a wide range of targets, allowing them to modulate many pathways critical to cancer progression, including proliferation, cell death, metastasis, angiogenesis, and drug resistance. This review explores our current understanding of miRNAs that are differentially modulated and pathologically involved in GBM as well as the current state of miRNA‐based therapeutics. As the role of miRNAs in GBM becomes more well understood and novel delivery methods are developed and optimized, miRNA‐based therapies could provide a critical step forward in cancer treatment.

This atomic force microscopy (AFM) study is devoted to the analysis of the mouse ovarian cancer cell's cytoskeleton components and the impact of both actin and microtubulin filaments on a cell's deformation behavior. Early stage, non-tumorigenic cancer cells show abundant well-organized cytoskeletal structures consisting of both actin and microtubule filaments. In sharp contrast, cells representing late and more aggressive stages of cancer display highly disorganized actin and microtubule structures. With the use of actin microfilament targeting drugs, together with the suberoylanilide hydroxamic acid (SAHA) and tubastatin A anti-cancer drugs, we modified the cell architectural framework and performed nano-indentation tests to evaluate cell elasticity and viscosity as a function of each biopolymer's weighted presence. Results demonstrate that both mechanical properties are heavily influenced by the levels and organization state of actin microfilaments; decreasing the actin organization of cells results in 85% and 79% decrease in cell elasticity and viscosity, respectively. In contrast, microtubule organization was shown to exert only marginal effects on either property. Furthermore, the anti-cancer drug, SAHA, was shown to exert little impact on the viscoelastic response of cancer cells. Finally, we report for the first time that tubastatin A, a specific HDAC6 inhibitor, increased cell elasticity as revealed by AFM tests without exerting drastic changes to the actin microfilament or microtubule networks. Our findings raise interest in a potential HDAC6 target that affects cellular mechanics just as effectively as the conventionally known cytoskeleton components.

Ovarian cancer is an insidious and aggressive disease of older women, typically undiscovered prior to peritoneal metastasis due to its asymptomatic nature and lack of early detection tools. Epidemiological studies suggest that child-bearing (parity) is associated with decreased ovarian cancer risk, although the molecular mechanisms responsible for this phenomenon have not been delineated. Ovarian cancer preferentially metastasizes to the omental fat band (OFB), a secondary lymphoid organ that aids in filtration of the peritoneal serous fluid (PSF) and helps combat peritoneal infections. In the present study we assessed how parity and age impact the immune compositional profile in the OFB of mice, both in the homeostatic state and as a consequence of peritoneal implantation of ovarian cancer. Using fluorescence-activated cell sorting analysis and quantitative realtime PCR, we found that parity was associated with a significant reduction in omental monocytic subsets and B1-B lymphocytes, correlating with reduced homeostatic expression levels of key chemoattractants and polarization factors (Ccl1, Ccl2, Arg1, Cxcl13). Of note, parous animals exhibited significantly reduced tumor burden following intraperitoneal implantation compared to nulliparous animals. This was associated with a reduction in tumor-associated neutrophils and macrophages, as well as in the expression levels of their chemoattractants (Cxcl1, Cxcl5) in the OFB and PSF. These findings define a pre-existing “parity-associated microenvironmental niche” in the OFB that is refractory to metastatic tumor seeding and outgrowth. Future studies designed to manipulate this niche may provide a novel means to mitigate peritoneal dissemination of ovarian cancer.

White adipose tissue (WAT) is a multi-faceted endocrine organ involved in energy storage, metabolism, immune function and disease pathogenesis. In contrast to subcutaneous fat, visceral fat (V-WAT) has been associated with numerous diseases and metabolic disorders, indicating specific functions related to anatomical location. Although visceral depots are often used interchangeably in V-WAT-associated disease studies, there has been a recent subdivision of V-WAT into “true visceral” and non-visceral intra-abdominal compartments. These were associated with distinct physiological roles, illustrating a need for depot-specific information. Here, we use FACS analysis to comparatively characterize the leukocyte and progenitor populations in the stromal vascular fraction (SVF) of peritoneal serous fluid (PSF), parametrial (pmWAT), retroperitoneal (rpWAT), and omental (omWAT) adipose tissue from seven-month old C57BL/6 female mice. We found significant differences in SVF composition between all four microenvironments. PSF SVF was comprised almost entirely of CD45+ leukocytes (>99%), while omWAT contained less, but still almost two-fold more leukocytes than pmWAT and rpWAT (75%, 38% and 38% respectively; p<0.01). PmWAT was composed primarily of macrophages, whereas rpWAT more closely resembled omWAT, denoted by high levels of B1 B-cell and monocyte populations. Further, omWAT harbored significantly higher proportions of T-cells than the other tissues, consistent with its role as a secondary lymphoid organ. These SVF changes were also reflected in the gene expression profiles of the respective tissues. Thus, intra-abdominal fat pads represent independent immunomodulatory microenvironments and should be evaluated as distinct entities with unique contributions to physiological and pathological processes.

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