Correction: Bischoff et al. The Effects of the Food Additive Titanium Dioxide (E171) on Tumor Formation and Gene Expression in the Colon of a Transgenic Mouse Model for Colorectal Cancer. Nanomaterials 2022, 12, 1256.

In the published publication [...].

Reply to Kaminski, N.E.; Cohen, S.M. Comment on "Bischoff et al. The Effects of the Food Additive Titanium Dioxide (E171) on Tumor Formation and Gene Expression in the Colon of a Transgenic Mouse Model for Colorectal Cancer. Nanomaterials 2022, 12, 1256".

We appreciate the interest in our article describing transcriptome changes in a transgenic mouse model carrying an APC gene mutation and would like to reply to the reader [...].

Mexican Colorectal Cancer Research Consortium (MEX-CCRC): Etiology, Diagnosis/Prognosis, and Innovative Therapies.

In 2013, recognizing that Colorectal Cancer (CRC) is the second leading cause of death by cancer worldwide and that it was a neglected disease increasing rapidly in Mexico, the community of researchers at the Biomedicine Research Unit of the Facultad de Estudios Superiores Iztacala from the Universidad Nacional Autónoma de México (UNAM) established an intramural consortium that involves a multidisciplinary group of researchers, technicians, and postgraduate students to contribute to the understanding of this pathology in Mexico. This article is about the work developed by the Mexican Colorectal Cancer Research Consortium (MEX-CCRC): how the Consortium was created, its members, and its short- and long-term goals. Moreover, it is a narrative of the accomplishments of this project. Finally, we reflect on possible strategies against CRC in Mexico and contrast all the data presented with another international strategy to prevent and treat CRC. We believe that the Consortium's characteristics must be maintained to initiate a national strategy, and the reported data could be useful to establish future collaborations with other countries in Latin America and the world.

The Effects of the Food Additive Titanium Dioxide (E171) on Tumor Formation and Gene Expression in the Colon of a Transgenic Mouse Model for Colorectal Cancer.

Titanium dioxide (TiO2) is present in many different food products as the food additive E171, which is currently scrutinized due to its potential adverse effects, including the stimulation of tumor formation in the gastrointestinal tract. We developed a transgenic mouse model to examine the effects of E171 on colorectal cancer (CRC), using the Cre-LoxP system to create an Apc-gene-knockout model which spontaneously develops colorectal tumors. A pilot study showed that E171 exposed mice developed colorectal adenocarcinomas, which were accompanied by enhanced hyperplasia in epithelial cells, lymphatic nodules at the base of the polyps, and increased tumor size. In the main study, tumor formation was studied following the exposure to 5 mg/kgbw/day of E171 for 9 weeks (Phase I). E171 exposure showed a statistically nonsignificant increase in the number of colorectal tumors in these transgenic mice, as well as a statistically nonsignificant increase in the average number of mice with tumors. Gene expression changes in the colon were analyzed after exposure to 1, 2, and 5 mg/kgbw/day of E171 for 2, 7, 14, and 21 days (Phase II). Whole-genome mRNA analysis revealed the modulation of genes in pathways involved in the regulation of gene expression, cell cycle, post-translational modification, nuclear receptor signaling, and circadian rhythm. The processes associated with these genes might be involved in the enhanced tumor formation and suggest that E171 may contribute to tumor formation and progression by modulation of events related to inflammation, activation of immune responses, cell cycle, and cancer signaling.

STAT1 Is Required for Decreasing Accumulation of Granulocytic Cells via IL-17 during Initial Steps of Colitis-Associated Cancer.

Signal transducer and activator of transcription 1 (STAT1) acts as a tumor suppressor molecule in colitis-associated colorectal cancer (CAC), particularly during the very early stages, modulating immune responses and controlling mechanisms such as apoptosis and cell proliferation. Previously, using an experimental model of CAC, we reported increased intestinal cell proliferation and faster tumor development, which were consistent with more signs of disease and damage, and reduced survival in STAT1-/- mice, compared with WT counterparts. However, the mechanisms through which STAT1 might prevent colorectal cancer progression preceded by chronic inflammation are still unclear. Here, we demonstrate that increased tumorigenicity related to STAT1 deficiency could be suppressed by IL-17 neutralization. The blockade of IL-17 in STAT1-/- mice reduced the accumulation of CD11b+Ly6ClowLy6G+ cells resembling granulocytic myeloid-derived suppressor cells (MDSCs) in both spleen and circulation. Additionally, IL-17 blockade reduced the recruitment of neutrophils into intestinal tissue, the expression and production of inflammatory cytokines, and the expression of intestinal STAT3. In addition, the anti-IL-17 treatment also reduced the expression of Arginase-1 and inducible nitric oxide synthase (iNOS) in the colon, both associated with the main suppressive activity of MDSCs. Thus, a lack of STAT1 signaling induces a significant change in the colonic microenvironment that supports inflammation and tumor formation. Anti-IL-17 treatment throughout the initial stages of CAC related to STAT1 deficiency abrogates the tumor formation possibly caused by myeloid cells.

Differential response of immobile (pneumocytes) and mobile (monocytes) barriers against 2 types of metal oxide nanoparticles.

BACKGROUND: Inhaled nanoparticles (NPs) challenges mobile and immobile barriers in the respiratory tract, which can be represented by type II pneumocytes (immobile) and monocytes (mobile) but what is more important for biological effects, the cell linage, or the type of nanoparticle? Here, we addressed these questions and we demonstrated that the type of NPs exerts a higher influence on biological effects, but cell linages also respond differently against similar type of NPs. DESIGN: Type II pneumocytes and monocytes were exposed to tin dioxide (SnO2) NPs and titanium dioxide (TiO2) NPs (1, 10 and 50 µg/cm2) for 24 h and cell viability, ultrastructure, cell granularity, molecular spectra of lipids, proteins and nucleic acids and cytoskeleton architecture were evaluated. RESULTS: SnO2 NPs and TiO2 NPs are metal oxides with similar physicochemical properties. However, in the absence of cytotoxicity, SnO2 NPs uptake was low in monocytes and higher in type II pneumocytes, while TiO2 NPs were highly internalized by both types of cells. Monocytes exposed to both types of NPs displayed higher number of alterations in the molecular patterns of proteins and nuclei acids analyzed by Fourier-transform infrared spectroscopy (FTIR) than type II pneumocytes. In addition, cells exposed to TiO2 NPs showed more displacements in FTIR spectra of biomolecules than cells exposed to SnO2 NPs. Regarding cell architecture, microtubules were stable in type II pneumocytes exposed to both types of NPs but actin filaments displayed a higher number of alterations in type II pneumocytes and monocytes exposed to SnO2 NPs and TiO2 NPs. NPs exposure induced the formation of large vacuoles only in monocytes, which were not seen in type II pneumocytes. CONCLUSIONS: Most of the cellular effects are influenced by the NPs exposure rather than by the cell type. However, mobile, and immobile barriers in the respiratory tract displayed differential response against SnO2 NPs and TiO2 NPs in absence of cytotoxicity, in which monocytes were more susceptible than type II pneumocytes to NPs exposure.

Combination of Metformin, Sodium Oxamate and Doxorubicin Induces Apoptosis and Autophagy in Colorectal Cancer Cells via Downregulation HIF-1α.

Colorectal cancer (CRC) is the third leading cause of cancer-related death worldwide in both sexes. Current therapies include surgery, chemotherapy, and targeted therapy; however, prolonged exposure to chemical agents induces toxicity in patients and drug resistance. So, we implemented a therapeutic strategy based on the combination of doxorubicin, metformin, and sodium oxamate called triple therapy (Tt). We found that Tt significantly reduced proliferation by inhibiting the mTOR/AKT pathway and promoted apoptosis and autophagy in CRC derived cells compared with doxorubicin. Several autophagy genes were assessed by western blot; ULK1, ATG4, and LC3 II were overexpressed by Tt. Interestingly, ULK1 was the only one autophagy-related protein gradually overexpressed during Tt administration. Thus, we assumed that there was a post-transcriptional mechanism mediating by microRNAs that regulate UKL1 expression during autophagy activation. Through bioinformatics approaches, we ascertained that ULK1 could be targeted by mir-26a, which is overexpressed in advanced stages of CRC. In vitro experiments revealed that overexpression of mir-26a decreased significantly ULK1, mRNA, and protein expression. Contrariwise, the Tt recovered ULK1 expression by mir-26a decrease. Due to triple therapy repressed mir-26a expression, we hypothesized this drug combination could be involved in mir-26a transcription regulation. Consequently, we analyzed the mir-26a promoter sequence and found two HIF-1α transcription factor recognition sites. We developed two different HIF-1α stabilization models. Both showed mir-26a overexpression and ULK1 reduction in hypoxic conditions. Immunoprecipitation experiments were performed and HIF-1α enrichment was observed in mir-26a promoter. Surprisingly, Tt diminished HIF-1α detection and restored ULK1 mRNA expression. These results reveal an important regulation mechanism controlled by the signaling that activates HIF-1α and that in turn regulates mir-26a transcription.

Food-grade titanium dioxide (E171) induces anxiety, adenomas in colon and goblet cells hyperplasia in a regular diet model and microvesicular steatosis in a high fat diet model.

Food-grade titanium dioxide (E171) is a white additive widely used in solid and liquid food products. There is still debate about E171 toxic effects after oral consumption since this additive is deposited in colon, liver, spleen, testis and brain. The consumption of E171 commonly occurs with Western diets that are characterized by a high fat content. Thus, E171 could worsen adverse effects associated with a high fat diet (HFD) such as anxiety, colon diseases and testicular damage. We aimed to evaluate the effects of E171 on anxiety-like behavior, colon, liver and testis and to analyze if the administration of a HFD could exacerbate adverse effects. E171 was administered at ~5 mg/kgbw by drinking water for 16 weeks and mice were fed with a Regular Diet or a HFD. E171 promoted anxiety, induced adenomas in colon, goblet cells hypertrophy and hyperplasia and mucins overexpression, but had no toxic effects on testicular tissue or spermatozoa in regular diet fed-mice. Additionally, E171 promoted microvesicular steatosis in liver in HFD fed-mice and the only HFD administration decreased the spermatozoa concentration and motility. In conclusion, E171 administration increases the number of adenomas in colon, induces hypertrophy and hyperplasia in goblet cells and microvesicular steatosis.

Toxicity of engineered nanomaterials with different physicochemical properties and the role of protein corona on cellular uptake and intrinsic ROS production.

The Organisation for Economic Co-operation and Development has listed thirteen engineered nanomaterials (ENM) in order to investigate their toxicity on human health. Silicon dioxide (SiO2) and titanium dioxide (TiO2) are included on that list and we added indium tin oxide (ITO) nanoparticles (NPs) to our study, which is not listed on OECD suggested ENM to be investigated, however ITO NPs has a high potential of industrial production. We evaluate the physicochemical properties of SiO2 NPs (10-20 nm), TiO2 nanofibers (NFs; 3 µm length) and ITO NPs (<50 nm) and the impact of protein-corona formation on cell internalization. Then, we evaluated the toxicity of uncoated ENM on human lung epithelial cells exposed to 10 and 50 µg/cm2 for 24 h. TiO2 NFs showed the highest capability to adsorb proteins onto the particle surface followed by SiO2 NPs and ITO NPs after acellular incubation with fetal bovine serum. The protein adsorption had no impact on Alizarin Red S conjugation, intrinsic properties for reactive oxygen (ROS) formation or cell uptake for all types of ENM. Moreover, TiO2 NFs induced highest cell alterations in human lung epithelial cells exposed to 10 and 50 µg/cm2 while ITO NPs induced moderated cytotoxicity and SiO2 NPs caused even lower cytotoxicity under the same conditions. DNA, proteins and lipids were mainly affected by TiO2 NFs followed by SiO2 NPs with toxic effects in protein and lipids while limited variations were detected after exposure to ITO NPs on spectra analyzed by Fourier Transform Infrared Spectroscopy.

Irreversible disruption of the cytoskeleton as induced by non-cytotoxic exposure to titanium dioxide nanoparticles in lung epithelial cells.

Exposure to TiO2 NPs induces several cellular alterations after NPs uptake including disruption of cytoskeleton that is crucial for lung physiology but is not considered as a footprint of cell damage. We aimed to investigate cytoskeleton disturbances and the impact on cell migration induced by an acute TiO2 NPs exposure (24 h) and the recovery capability after 6 days of NPs-free treatment, which allowed investigating if cytoskeleton damage was reversible. Exposure to TiO2 NPs (10 µg/cm2) for 24 h induced a decrease 20.2% and 25.1% in tubulin and actin polymerization. Exposure to TiO2 NPs (10 µg/cm2) for 24 h followed by 6 days of NPs-free had a decrease of 26.6% and 21.3% in tubulin and actin polymerization, respectively. The sustained exposure for 7 days to 1 µg/cm2 and 10 µg/cm2 induced a decrease of 22.4% and 30.7% of tubulin polymerization respectively, and 28.7% and 46.2% in actin polymerization. In addition, 24 h followed 6 days of NPs-free exposure of TiO2 NPs (1 µg/cm2 and 10 µg/cm2) decreased cell migration 40.7% and 59.2%, respectively. Cells exposed (10 µg/cm2) for 7 days had a decrease of 65.5% in cell migration. Ki67, protein surfactant B (SFTPB) and matrix metalloprotease 2 (MMP2) were analyzed as genes related to lung epithelial function. The results showed a 20% of Ki67 upregulation in cells exposed for 24 h to 10 µg/cm2 TiO2 NPs while a downregulation of 20% and 25.8% in cells exposed to 1 µg/cm2 and 10 µg/cm2 for 24 h followed by 6 days of NPs-free exposure. Exposure to 1 µg/cm2 and 10 µg/cm2 for 24 h and 7 days upregulates SFTPB expression in 53% and 59% respectively, MMP2 expression remain unchanged. In conclusion, exposure of TiO2 NPs affected cytoskeleton of lung epithelial cells irreversibly but this damage was not cumulative.

Use of STAT6 Phosphorylation Inhibitor and Trimethylglycine as New Adjuvant Therapies for 5-Fluorouracil in Colitis-Associated Tumorigenesis.

Colorectal cancer (CRC) is one of the most widespread and deadly types of neoplasia around the world, where the inflammatory microenvironment has critical importance in the process of tumor growth, metastasis, and drug resistance. Despite its limited effectiveness, 5-fluorouracil (5-FU) is the main drug utilized for CRC treatment. The combination of 5-FU with other agents modestly increases its effectiveness in patients. Here, we evaluated the anti-inflammatory Trimethylglycine and the Signal transducer and activator of transcription (STAT6) inhibitor AS1517499, as possible adjuvants to 5-FU in already established cancers, using a model of colitis-associated colon cancer (CAC). We found that these adjuvant therapies induced a remarkable reduction of tumor growth when administrated together with 5-FU, correlating with a reduction in STAT6-phosphorylation. This reduction upgraded the effect of 5-FU by increasing both levels of apoptosis and markers of cell adhesion such as E-cadherin, whereas decreased epithelial-mesenchymal transition markers were associated with aggressive phenotypes and drug resistance, such as ß-catenin nuclear translocation and Zinc finger protein SNAI1 (SNAI1). Additionally, Il-10, Tgf-ß, and Il-17a, critical pro-tumorigenic cytokines, were downmodulated in the colon by these adjuvant therapies. In vitro assays on human colon cancer cells showed that Trimethylglycine also reduced STAT6-phosphorylation. Our study is relatively unique in focusing on the effects of the combined administration of AS1517499 and Trimethylglycine together with 5-FU on already established CAC which synergizes to markedly reduce the colon tumor load. Together, these data point to STAT6 as a valuable target for adjuvant therapy in colon cancer.

Differences in cytotoxicity of lung epithelial cells exposed to titanium dioxide nanofibers and nanoparticles: Comparison of air-liquid interface and submerged cell cultures.

Air Liquid Interface (ALI) system has emerged as a useful tool for toxicity evaluation of nanomaterials related to inhalation since the system mimics the aerosol exposure. We compared the biological responses of lung epithelial cells exposed to titanium dioxide (TiO2) nanofibers and nanoparticles in ALI and submerged cell cultures systems. Cells were exposed to 2 and 10 µg/cm2 for 24 h, 48 h and 72 h and LDH release, TiO2 internalization, DNA-double strand breaks (DSBs) and ROS production were assessed. LDH release was similar in both systems and particles had higher cytoplasmic uptake in submerged systems. Both TiO2 types were located in the cytoplasm but nanofibers had nuclear uptake regardless to the system tested. Cells exposed to TiO2 nanofibers had higher DSBs in the ALI system than in submerged cell cultures but cells exposed to TiO2 nanoparticles had similar DSBs in both systems. ROS production was higher in cells exposed to TiO2 nanofibers compared to cells exposed to TiO2 nanoparticles. In conclusion, cytotoxicity of lung epithelial cells was similar in ALI or submerged cell cultures, however cells exposed to TiO2 nanofibers displayed higher toxicity than cells exposed to TiO2 nanoparticles.

International landscape of limits and recommendations for occupational exposure to engineered nanomaterials.

The increasing concern of possible adverse effects on human health derived from occupational engineered nanomaterials (ENMs) exposure is an issue addressed by entities related to provide guidelines and/or protocols for ENMs regulation. Here we analysed 17 entities from America, Europe and Asia, and some of these entities provide limits of exposure extrapolated from the non-nanosized counterparts of ENMs. The international landscape shows that recommendations are mostly made for metal oxide based ENMs and tonnage is one of the main criteria for ENMs registration, however, sub-nanometric ENMs are emerging and perhaps a novel category of ENMs will appear soon. We identify that besides the lack of epidemiological evidence of ENMs toxicity in humans and difficulties in analysing the toxicological data derived from experimental models, the lack of information on airborne concentrations of ENMs in occupational settings is an important limitation to improve the experimental designs. The development of regulations related to ENMs exposure would lead to provide safer work places for ENMs production without delaying the nanotechnology progress but will also help to protect the environment by taking opportune and correct measures for nanowaste, considering that this could be a great environmental problem in the coming future.

Helminth-derived molecules inhibit colitis-associated colon cancer development through NF-κB and STAT3 regulation.

Inflammation is currently considered a hallmark of cancer and plays a decisive role in different stages of tumorigenesis, including initiation, promotion, progression, metastasis and resistance to antitumor therapies. Colorectal cancer is a disease widely associated with local chronic inflammation. Additionally, extrinsic factors such as infection may beneficially or detrimentally alter cancer progression. Several reports have noted the ability of various parasitic infections to modulate cancer development, favoring tumor progression in many cases and inhibiting tumorigenesis in others. The aim of our study was to determine the effects of excreted/secreted products of the helminth Taenia crassiceps (TcES) as a treatment in a murine model of colitis-associated colon cancer (CAC). Here, we found that after inducing CAC, treatment with TcES was able to reduce inflammatory cytokines such as IL-1ß, TNF-α, IL-33 and IL-17 and significantly attenuate colon tumorigenesis. This effect was associated with the inhibition of signal transducer and activator of transcription 3 and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) phosphorylation. Furthermore, we determined that TcES interfered with LPS-induced NF-κB p65 activation in human colonic epithelial cell lines in a Raf-1 proto-oncogene-dependent manner. Moreover, in three-dimensional cultures, TcES promoted reorganization of the actin cytoskeleton, altering cell morphology and forming colonospheres, features associated with a low grade of aggressiveness. Our study demonstrates a remarkable effect of helminth-derived molecules on suppressing ongoing colorectal cancer by downregulating proinflammatory and protumorigenic signaling pathways.

Food-grade titanium dioxide (E171) by solid or liquid matrix administration induces inflammation, germ cells sloughing in seminiferous tubules and blood-testis barrier disruption in mice.

Food-grade titanium dioxide labeled as E171 has been approved for human consumption by the Food and Drug Administration (USA) and by the European Union for five decades. However, titanium dioxide has been classified as a possible carcinogen for humans by the International Agency of Research in Cancer raising concerns of its oral intake and the translocation to bloodstream, which could disturb barriers such as the blood-testis barrier. There is evidence that titanium dioxide by intragastric/intraperitoneal/intravenous administration induced alterations on testosterone levels, testicular function and architecture, but studies of the E171 effects on the testicle structure and blood-testis barrier are limited. E171 is contained not only in foods in liquid matrix but also in solid ones, which can exert different biological effects. We aimed to compare the effects of E171 consumption in a solid matrix (0.1%, 0.5% and 1% in pellets) and liquid suspension (5 mg/kg body weight) on testis structure, inflammation infiltrate and blood-testis barrier disruption of male BALB/c mice. Results showed that none of the administration routes had influence on body weight but an increase in germ cell sloughing and the infiltrate of inflammatory cells in seminiferous tubules, together with disruption of the blood-testis barrier were similar in testis of both groups even if the dose received in mice in liquid matrix was 136 or 260 times lower than the dose reached by oral intake in solid E171 pellets in 0.5% E171 and 1% E171, respectively. This study highlights the attention on matrix food containing E171 and possible adverse effects on testis when E171 is consumed in a liquid matrix.

Deficiency in STAT1 Signaling Predisposes Gut Inflammation and Prompts Colorectal Cancer Development.

Signal transducer and activator of transcription 1 (STAT1) is part of the Janus kinase (JAK/STAT) signaling pathway that controls critical events in intestinal immune function related to innate and adaptive immunity. Recent studies have implicated STAT1 in tumor⁻stroma interactions, and its expression and activity are perturbed during colon cancer. However, the role of STAT1 during the initiation of inflammation-associated cancer is not clearly understood. To determine the role of STAT1 in colitis-associated colorectal cancer (CAC), we analyzed the tumor development and kinetics of cell recruitment in wild-type WT or STAT1-/- mice treated with azoxymethane (AOM) and dextran sodium sulfate (DSS). Following CAC induction, STAT1-/- mice displayed an accelerated appearance of inflammation and tumor formation, and increased damage and scores on the disease activity index (DAI) as early as 20 days after AOM-DSS exposure compared to their WT counterparts. STAT1-/- mice showed elevated colonic epithelial cell proliferation in early stages of injury-induced tumor formation and decreased apoptosis in advanced tumors with over-expression of the anti-apoptotic protein Bcl2 at the colon. STAT1-/- mice showed increased accumulation of Ly6G⁺Ly6C-CD11b⁺ cells in the spleen at 20 days of CAC development with concomitant increases in the production of IL-17A, IL-17F, and IL-22 cytokines compared to WT mice. Our findings suggest that STAT1 plays a role as a tumor suppressor molecule in inflammation-associated carcinogenesis, particularly during the very early stages of CAC initiation, modulating immune responses as well as controlling mechanisms such as apoptosis and cell proliferation.

Influence of shape and dispersion media of titanium dioxide nanostructures on microvessel network and ossification.

Titanium dioxide nanoparticles (TiO2 NPs) production has been used for pigment, food and cosmetic industry and more recently, shaped as belts for treatment of contaminated water, self-cleaning windows and biomedical applications. However, the toxicological data have demonstrated that TiO2 NPs inhalation induce inflammation in in vivo models and in vitro exposure leads to cytotoxicity and DNA damage. Dermal exposure has limited adverse effects and the possible risks for implants used for tissue regeneration is still under research. Then, it has been difficult to establish a straight statement about TiO2 NPs toxicity since route of exposure and shapes of nanoparticles play an important role in the effects. In this study we aimed to investigate the effect of three different types of TiO2 NPs (industrial, food-grade and belts) dispersed in fetal bovine serum (FBS) and saline solution (SS) on microvessel network, angiogenesis gene expression and femur ossification using a chick embryo model after an acute exposure of NPs on the day 7 after eggs fertilization. Microvascular density of chorioallantoic membrane (CAM) was analyzed after 7days of NPs injection and vehicles induced biological effects per se. NPs dispersed in FBS or SS have slight differences in microvascular density, mainly opposite effect on angiogenesis gene expression and no effects on femur ossification for NPs dispersed in SS. Interestingly, NPs shaped as belts dramatically prevented the alterations in ossification induced by FBS used as vehicle.

Lack of STAT6 Attenuates Inflammation and Drives Protection against Early Steps of Colitis-Associated Colon Cancer.

Colitis-associated colon cancer (CAC) is one of the most common malignant neoplasms and a leading cause of death. The immunologic factors associated with CAC development are not completely understood. Signal transducer and activator of transcription 6 (STAT6) is part of an important signaling pathway for modulating intestinal immune function and homeostasis. However, the role of STAT6 in colon cancer progression is unclear. Following CAC induction in wild-type (WT) and STAT6-deficient mice (STAT6-/-), we found that 70% of STAT6-/- mice were tumor-free after 8 weeks, whereas 100% of WT mice developed tumors. STAT6-/- mice displayed fewer and smaller colorectal tumors than WT mice; this reduced tumorigenicity was associated with decreased proliferation and increased apoptosis in the colonic mucosa in the early steps of tumor progression. STAT6-/- mice also exhibited reduced inflammation, diminished concentrations COX2 and nuclear ß-catenin protein in the colon, and decreased mRNA expression of IL17A and TNFα, but increased IL10 expression when compared with WT mice. Impaired mucosal expression of CCL9, CCL25, and CXCR2 was also observed. In addition, the number of circulating CD11b+Ly6ChiCCR2+ monocytes and CD11b+Ly6ClowLy6G+ granulocytes was both decreased in a STAT6-dependent manner. Finally, WT mice receiving a STAT6 inhibitor in vivo confirmed a significant reduction in tumor load as well as less intense signs of CAC. Our results demonstrate that STAT6 is critical in the early steps of CAC development for modulating inflammatory responses and controlling cell recruitment and proliferation. Thus, STAT6 may represent a promising target for CAC treatment. Cancer Immunol Res; 5(5); 385-96. ©2017 AACR.

Role of Wasp and the small GTPases RhoA, RhoB, and Cdc42 during capacitation and acrosome reaction in spermatozoa of English guinea pigs.

Cytoskeleton remodeling is necessary for capacitation and the acrosome reaction in spermatozoa. F-actin is located in the acrosome and equatorial region during capacitation, but is relocated in the post-acrosomal region during the acrosome reaction in spermatozoa from bull, rat, mice, and guinea pig. Actin polymerization and relocalization are generally regulated by small GTPases that activate Wasp protein, which coordinates with Arp2/3, profilin I, and profilin II to complete cytoskeletal remodeling. This sequence of events is not completely described in spermatozoa, though. Therefore, the aim of this study was to determine if Wasp interacts with small GTPases (RhoA, RhoB, and Cdc42) and proteins (Arp2/3, profilin I, and profilin II) that co-localize with F-actin during capacitation and the acrosome reaction in English guinea pig spermatozoa obtained from the vas deferens. The spermatozoa were capacitated in calcium-free medium, incubated with an activator or an inhibitor of GTPases, and then induced to acrosome react using calcium. The distribution patterns of F-actin were compared to the patterns of Wasp and its putative interaction partners: Wasp and RhoB, but not RhoA or Cdc42, localization overlap with F-actin during capacitation and the acrosome reaction. Activation of small GTPases localized RhoB to the post-acrosomal region whereas their inhibition prevented acrosome exocytosis. Arp2/3 and profilin II appear to interact with Wasp in the post-acrosomal region and flagellum, while profilin I and Wasp could be found in the equatorial region. Thus, Wasp and F-actin distribution overlap during capacitation and acrosome reaction, and small GTPases play an important role in cytoskeleton remodeling during these processes in spermatozoa. Mol. Reprod. Dev. 83: 927-937, 2016 © 2016 Wiley Periodicals, Inc.

Food-grade titanium dioxide exposure exacerbates tumor formation in colitis associated cancer model.

Colorectal cancer is the fourth worldwide cause of death and even if some dietary habits are consider risk factors, the contribution of food additives including foodgrade titanium dioxide (TiO2), designated as E171, has been poorly investigated. We hypothesized that oral E171 intake could have impact on the enhancement of colorectal tumor formation and we aimed to investigate if E171 administration could enhance tumor formation in a colitis associated cancer (CAC) model. BALB/c male mice were grouped as follows: a) control, b) E171, c) CAC and d) CAC + E171 group (n = 6). E171 used in this study formed agglomerates of 300 nm in water. E171 intragastric administration (5 mg/kg body weight/5 days/10 weeks) was unable to induce tumor formation but dysplastic alterations were observed in the distal colon but enhanced the tumor formation in distal colon (CAC + E171 group) measured by tumor progression markers. Some E171 particles were internalized in colonic cells of the E171 and CAC + E171 groups and both groups showed a decrease in goblet cells in the distal colon. However the CAC + E171 group showed a higher decrease of these cells that act as protection barrier in colon. These results suggest that E171 could worsen pre-existent intestinal diseases.