Structural expression of bovine milk and meat factors in tissues of colorectal, lung and pancreatic cancer patients.

Chronic inflammation, linked to the presence of bovine milk and meat factors (BMMFs) and specific subsets of macrophages, results in oxygen radical synthesis and induction of mutations in DNA of actively replicating cells and replicating single stranded DNA. Cancers arising from this process have been characterized as indirect carcinogenesis by infectious agents (without persistence of genes of the agent in premalignant or cancers cells). Here, we investigate structural properties of pleomorphic vesicles, regularly identified by staining peritumor tissues of colorectal, lung and pancreatic cancer for expression of BMMF Rep. The latter represents a subgroup of BMMF1 proteins involved in replication of small single-stranded circular plasmids of BMMF, but most likely also contributing to pleomorphic vesicular structures found in the periphery of colorectal, lung and pancreatic cancers. Structurally dense regions are demonstrated in preselected areas of colorectal cancer, after staining with monoclonal antibodies against BMMF1 Rep. Similar structures were observed in human embryonic cells (HEK293TT) overexpressing Rep. These data suggest that Rep or Rep isoforms contribute to the structural formation of vesicles.

Repression of the iron exporter ferroportin may contribute to hepatocyte iron overload in individuals with type 2 diabetes.

OBJECTIVE: Hyperferremia and hyperferritinemia are observed in patients and disease models of type 2 diabetes mellitus (T2DM). Likewise, patients with genetic iron overload diseases develop diabetes, suggesting a tight link between iron metabolism and diabetes. The liver controls systemic iron homeostasis and is a central organ for T2DM. Here, we investigate how the control of iron metabolism in hepatocytes is affected by T2DM. METHODS: Perls Prussian blue staining was applied to analyze iron distribution in liver biopsies of T2DM patients. To identify molecular mechanisms underlying hepatocyte iron accumulation we established cellular models of insulin resistance by treatment with palmitate and insulin. RESULTS: We show that a subset of T2DM patients accumulates iron in hepatocytes, a finding mirrored in a hepatocyte model of insulin resistance. Iron accumulation can be explained by the repression of the iron exporter ferroportin upon palmitate and/or insulin treatment. While during palmitate treatment the activation of the iron regulatory hormone hepcidin may contribute to reducing ferroportin protein levels in a cell-autonomous manner, insulin treatment decreases ferroportin transcription via the PI3K/AKT and Ras/Raf/MEK/ERK signaling pathways. CONCLUSION: Repression of ferroportin at the transcriptional and post-transcriptional level may contribute to iron accumulation in hepatocytes observed in a subset of patients with T2DM.

Mad2 Induced Aneuploidy Contributes to Eml4-Alk Driven Lung Cancer by Generating an Immunosuppressive Environment.

Aneuploidy, an imbalance number of chromosomes, is frequently observed in lung cancer and inversely correlates with patient survival. Paradoxically, an aneuploid karyotype has detrimental consequences on cellular fitness, and it has been proposed that aneuploid cells, at least in vitro, generate signals for their own elimination by NK cells. However, how aneuploidy affects tumor progression as well as the interplay between aneuploid tumor cells and the tumor microenvironment is still unclear. We generated a new mouse model in which overexpression of Mad2 was almost entirely restricted to normal epithelial cells of the lung, and combined it with an oncogenic Eml4-Alk chromosome inversion. This combination resulted in a higher tumor burden and an increased number of tumor nodules compared to control Eml4-Alk mice alone. The FISH analysis detected significant differences in the aneuploidy levels in the non-tumor regions of Eml4-Alk+Mad2 compared to Eml4-Alk alone, although both tumor groups presented similar levels of aneuploidy. We further show that aneuploid cells in the non-tumor areas adjacent to lung tumors recruit immune cells, such as tumor-associated macrophages. In fact, these areas presented an increase in alveolar macrophages, neutrophils, decreased cytotoxic CD8+ T cells, and IFN-γ, suggesting that aneuploid cells in the surrounding tumor areas create an immunosuppressive signature that might contribute to lung tumor initiation and progression.

Regulation of iron homeostasis: Lessons from mouse models.

Iron is an essential micronutrient and a critical cofactor for proteins involved in fundamental processes such as oxygen transport, energy production and DNA synthesis. However, iron levels need to be tightly balanced to avoid pathological consequences of iron overload or deficiency. Genetically engineered mouse models with alterations in systemic or cellular iron handling advanced our knowledge how systemic and cellular iron homeostasis is maintained. Here, we prepared a comprehensive overview of mouse models that provide insight into mechanisms of iron regulation and/or rare or frequent iron-related disorders.

Targeting alveolar macrophages shows better treatment response than deletion of interstitial macrophages in EGFR mutant lung adenocarcinoma.

INTRODUCTION: Alveolar macrophages (AMs) are critical in the development of lung adenocarcinoma driven by epidermal growth factor receptor (EGFR) mutations. Whether interstitial macrophages (IMs) are also involved in lung tumorigenesis is still unclear. Thus, the aim of this study is to evaluate the role of both AM and IM in the development of EGFR mutant driven lung adenocarcinoma. METHODS: We used the EGFR mutant doxycycline-inducible mouse model of lung adenocarcinoma to deplete interstitial or AMs by clodronate-encapsulated liposomes administered intravenously (IV) and intratracheally (IT), respectively. Tumor burden, AMs, and the tumor microenvironment were examined by immunohistochemistry, bronchoalveolar lavage fluid or flow cytometry. RESULTS: Clodronate treatment resulted in a significant reduction of tumor burden compared with vehicle liposomes alone. Elimination of AMs resulted in a significant reduction of proliferation compared with IV treatment. However, both treatments resulted in a significantly higher number of Ki67 positive cells compared with control mice, suggesting that tumor cells still proliferate despite the treatment. The number of natural killer cells decreased during tumor development, and it remained low even after the elimination of AMs. We also observed that IT instillation of clodronate significantly increased the number of CD8+ T cells, which was higher compared with vehicle-treated mice and mice where only IMs were depleted. The similar trend was observed in immunohistological analyses of CD8+ T cells. CONCLUSIONS: These results suggest that the reduction of AMs has a stronger impact on restricting tumor progression compared with targeting IMs. The depletion of AMs leads to an elevated infiltration of CD8+ T cells into the lung that might be responsible for tumor growth impairment. Altogether, elimination of AMs is a better strategy to reduce EGFR mutant tumor growth and is less toxic, suggesting the selectively targeting of AMs to complement established therapies.

Corticosteroids compromise survival in glioblastoma.

Glioblastoma is the most common and most aggressive primary brain tumour. Standard of care consists of surgical resection followed by radiotherapy and concomitant and maintenance temozolomide (temozolomide/radiotherapy→temozolomide). Corticosteroids are commonly used perioperatively to control cerebral oedema and are frequently continued throughout subsequent treatment, notably radiotherapy, for amelioration of side effects. The effects of corticosteroids such as dexamethasone on cell growth in glioma models and on patient survival have remained controversial. We performed a retrospective analysis of glioblastoma patient cohorts to determine the prognostic role of steroid administration. A disease-relevant mouse model of glioblastoma was used to characterize the effects of dexamethasone on tumour cell proliferation and death, and to identify gene signatures associated with these effects. A murine anti-VEGFA antibody was used in parallel as an alternative for oedema control. We applied the dexamethasone-induced gene signature to The Cancer Genome Atlas glioblastoma dataset to explore the association of dexamethasone exposure with outcome. Mouse experiments were used to validate the effects of dexamethasone on survival in vivo Retrospective clinical analyses identified corticosteroid use during radiotherapy as an independent indicator of shorter survival in three independent patient cohorts. A dexamethasone-associated gene expression signature correlated with shorter survival in The Cancer Genome Atlas patient dataset. In glioma-bearing mice, dexamethasone pretreatment decreased tumour cell proliferation without affecting tumour cell viability, but reduced survival when combined with radiotherapy. Conversely, anti-VEGFA antibody decreased proliferation and increased tumour cell death, but did not affect survival when combined with radiotherapy. Clinical and mouse experimental data suggest that corticosteroids may decrease the effectiveness of treatment and shorten survival in glioblastoma. Dexamethasone-induced anti-proliferative effects may confer protection from radiotherapy- and chemotherapy-induced genotoxic stress. This study highlights the importance of identifying alternative agents such as vascular endothelial growth factor antagonists for managing oedema in glioblastoma patients. Beyond the established adverse effect profile of protracted corticosteroid use, this analysis substantiates the request for prudent and restricted use of corticosteroids in glioblastoma.