Guillermina J. Baay-Guzman

Hypoxia Inducible Factor promotes murine allergic airway inflammation and is increased in asthma and rhinitis

To cite this article: Huerta‐Yepez S, Baay‐Guzman GJ, Bebenek IG, Hernandez‐Pando R, Vega MI, Chi L, Riedl M, Diaz‐Sanchez D, Kleerup E, Tashkin DP, Gonzalez FJ, Bonavida B, Zeidler M, Hankinson O. Hypoxia Inducible Factor promotes murine allergic airway inflammation and is increased in asthma and rhinitis. Allergy 2011; 66: 909–918.

In vitro and in vivo sensitization of SW620 metastatic colon cancer cells to CDDP-induced apoptosis by the nitric oxide donor DETANONOate: Involvement of AIF

Tumor cells develop mechanisms that dysregulate apoptotic pathways resulting in resistance to cytotoxic stimuli. Primary SW480 and metastatic SW620 colon cancer cells are resistant to CDDP-induced apoptosis. Apoptosis-inducing factor (AIF) was significantly downregulated in SW620 compared to SW480 cells; while apoptotic mediators such as Bax, Bcl-2, and Bcl(XL) were not altered in these cell lines. Examination of tumor tissues from patients with colon cancer demonstrated a significant downregulation of AIF in patients with advanced disease. The role of AIF expression in resistance was examined. Several lines of evidence suggest the involvement of AIF expression level in the sensitivity of SW620 to CDDP-induced apoptosis: (1) sensitization of SW620 by the NO donor DETANONOate to CDDP-induced apoptosis correlated with the induction of AIF as assessed by RT-PCR and Western blot analysis, (2) treatment of SW620 cells with siRNA AIF, but not with control siRNAs, inhibited DETANONOate-induced sensitization to CDDP apoptosis, (3) sensitization by DETANONOate observed in vitro was corroborated in vivo in nude mice bearing SW620 tumor xenografts and treated with the combination of DETANONOate and CDDP, and (4) tumor tissues derived from the SW620 xenografts revealed significant upregulation of AIF and increased apoptosis by DETANONOate and CDDP combination treatment. Altogether, these findings underscore the potential therapeutic application of NO donors and subtoxic chemotherapeutic drugs in the treatment of advanced colon cancer resistant to conventional chemotherapeutic agents.

Contribution of either YY1 or BclXL-induced inhibition by the NO-donor DETANONOate in the reversal of drug resistance, both in vitro and in vivo. YY1 and BclXL are overexpressed in prostate cancer.

Nitric oxide (NO) donors have been shown to activate or inhibit constitutively-activated survival/anti-apoptotic pathways, such as NF-κB, in cancer cells. We report here that treatment of drug-resistant human prostate carcinoma cell lines with high levels (500-1000 μM) of the NO-donor DETANONOate sensitized the resistant tumor cells to apoptosis by CDDP and the combination was synergistic. We hypothesized that DETANONOate inhibits previously identified NF-κB-regulated resistant factors such as Yin Yang 1 (YY1) and Bcl-2/BclXL. Lysates from tumor cells treated with DETANONOate showed inhibition of YY1 and BclXL expressions. Transfection with either YY1 or BclXL siRNA resulted in the inhibition of both YY1 and BclXL expressions and sensitized the cells to CDDP apoptosis. Mice bearing PC-3 tumor xenografts and treated with the combination of DETANONOate and CDDP resulted in significant inhibition of tumor growth; treatment with single agent alone did not have any effect on tumor growth. Analysis of patients TMA tissues with prostatic cancer revealed higher expression of both YY1 and BclXL as a function of tumor grades and their levels were directly correlated. Thus, both YY1 and BclXL are potential prognostic biomarkers. Overall, the above findings suggest that one mechanism of DETANONOate-induced sensitization of resistant tumor cells to CDDP correlated with the inhibition of NF-κB and its targets YY1 and BclXL. The examination of the combination of NO donors and cytotoxic therapy in the treatment of resistant prostate cancer may be warranted.

Diminished Expression of Corticotropin-Releasing Hormone Receptor 2 in Human Colon Cancer Promotes Tumor Growth and Epithelial-to-Mesenchymal Transition via Persistent Interleukin-6/Stat3 Signaling

Background & Aims Chronic inflammation promotes development and progression of colorectal cancer (CRC). We explored the distribution of the corticotropin-releasing-hormone (CRH) family of receptors and ligands in CRC and their contribution in tumor growth and oncogenic epithelial-to-mesenchymal transition (EMT). Methods The mRNA expression of CRH-family members was analyzed in CRC (n = 56) and control (n = 46) samples, seven CRC cell lines, and normal NCM460 cells. Immunohistochemical detection of CRHR2 was performed in 20 CRC and five normal tissues. Cell proliferation, migration, and invasion were compared between urocortin-2 (Ucn2)-stimulated parental and CRHR2-overexpressing (CRHR2+) cells in the absence or presence of interleukin-6 (IL-6). CRHR2/Ucn2-targeted effects on tumor growth and EMT were validated in SW620-xenograft mouse models. Results CRC tissues and cell lines showed decreased mRNA and protein CRHR2 expression compared with controls and NCM460 cells, respectively. The opposite trend was shown for Ucn2. CRHR2/Ucn2 signaling inhibited cell proliferation, migration, invasion, and colony formation in CRC-CRHR2+ cells. In vivo, SW620-CRHR2+ xenografts showed decreased growth, reduced expression of EMT-inducers, and elevated levels of EMT-suppressors. IL-1b, IL-6, and IL-6R mRNAs were diminished in CRC-CRHR2+ cells, while CRHR2/Ucn2 signaling inhibited IL-6-mediated Stat3 activation, invasion, migration, and expression of downstream targets acting as cell cycle– and EMT-inducers. Expression of cell cycle– and EMT-suppressors was augmented in IL-6/Ucn2-stimulated CRHR2+ cells. In patients, CRHR2 mRNA expression was inversely correlated with IL-6R and vimentin levels and metastasis occurrence, while positively associated with E-cadherin expression and overall survival. Conclusions CRHR2 down-regulation in CRC supports tumor expansion and spread through maintaining persistent inflammation and constitutive Stat3 activation. CRHR2low CRC phenotypes are associated with higher risk for distant metastases and poor clinical outcomes.

Virulence and Immune Response Induced by Mycobacterium avium Complex Strains in a Model of Progressive Pulmonary Tuberculosis and Subcutaneous Infection in BALB/c Mice

ABSTRACT The genus Mycobacterium comprises more than 150 species, including important pathogens for humans which cause major public health problems. The vast majority of efforts to understand the genus have been addressed in studies with Mycobacterium tuberculosis. The biological differentiation between M. tuberculosis and nontuberculous mycobacteria (NTM) is important because there are distinctions in the sources of infection, treatments, and the course of disease. Likewise, the importance of studying NTM is not only due to its clinical significance but also due to the mechanisms by which some species are pathogenic while others are not. Mycobacterium avium complex (MAC) is the most important group of NTM opportunistic pathogens, since it is the second largest medical complex in the genus after the M. tuberculosis complex. Here, we evaluated the virulence and immune response of M. avium subsp. avium and Mycobacterium colombiense, using experimental models of progressive pulmonary tuberculosis and subcutaneous infection in BALB/c mice. Mice infected intratracheally with a high dose of MAC strains showed high expression of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase with rapid bacillus elimination and numerous granulomas, but without lung consolidation during late infection in coexistence with high expression of anti-inflammatory cytokines. In contrast, subcutaneous infection showed high production of the proinflammatory cytokines TNF-α and gamma interferon with relatively low production of anti-inflammatory cytokines such as interleukin-10 (IL-10) or IL-4, which efficiently eliminate the bacilli but maintain extensive inflammation and fibrosis. Thus, MAC infection evokes different immune and inflammatory responses depending on the MAC species and affected tissue.

Role of CXCL13 in Asthma: Novel Therapeutic Target

BACKGROUND B cells play an important role in allergic asthma. However, the mechanisms by which these cells are activated in the airways remain poorly understood. METHODS We used a mouse model of ovalbumin (OVA)-induced allergic inflammation to study CXCL13 and to investigate the concentration of this chemokine in the BAL fluid derived from asthmatic and normal control subjects. RESULTS We found that OVA-challenged mice upregulate the CXCL13/CXCR5 axis, which is associated with several changes in their airways, including recruitment of B and CD4(+) cells, development of bronchial-associated lymphoid tissue, and airway inflammation. Treating sensitized mice with an anti-CXCL13 antibody reduced cell recruitment, bronchial-associated lymphoid tissue formation, and airways inflammation. Interestingly, measurements of CXCL13 using enzyme-linked immunosorbent assay showed that levels of this cytokine were significantly elevated in BAL fluid from subjects with asthma compared with control subjects (median, 162 [range, 120-296] vs 31 [range, 120-156] pg/mL; P = .005). CONCLUSIONS All together, these findings suggest that CXCL13 is involved in the allergic airway inflammatory process, and targeting this chemokine may constitute a novel approach in asthma.

Inhibition of tumor progression during allergic airway inflammation in a murine model: significant role of TGF-β

IntroductionTGF-β is an important mediator of pulmonary allergic inflammation, and it has been recently reported to be a potential inhibitor of lung tumor progression. The correlation between cancer and allergic inflammatory diseases remains controversial. Thus, the aim of the present study was to evaluate the effects of pulmonary allergic inflammation and in particular the role of TGF-β on cancer progression.MethodsCancer cells were implanted in a BALB/c mice model of allergic airway inflammation, and tumor growth was measured. Apoptosis was evaluated by TUNEL assay, and TGF-β was measured by ELISA. Expression of proliferating cell nuclear antigen, TGF-β, TGF-β receptors I and II, phospho-Smad2 and phospho-Smad4 was evaluated by immunohistochemistry and quantified using digital pathology. The effect of a TGF-β activity inhibitor and recombinant TGF-β on tumor growth was analyzed. The effect of exogenous TGF-β on cell proliferation and apoptosis was evaluated in vitro.ResultsMice with allergic airway inflammation exhibited decreased tumor volumes due to cell proliferation inhibition and increased apoptosis. TGF-β was increased in the sera and tumor tissues of allergic mice. TGF-β activity inhibition increased tumor progression in allergic mice by enhancing proliferation and decreasing apoptosis of tumor cells. The administration of TGF-β resulted in reduced tumor growth.ConclusionThis study is the first to establish an inverse relationship between allergic airway inflammation and tumor progression. This effect appears to be mediated by TGF-β, which is overexpressed in tumor cells during pulmonary allergic inflammation. This study indicates that TGF-β is a potential target for antitumor therapy.

A novel role of Yin-Yang-1 in pulmonary tuberculosis through the regulation of the chemokine CCL4

Mycobacterium tuberculosis (M. tb) is the etiological agent of pulmonary tuberculosis (TB); this disease remains a worldwide health problem. Yin-Yang-1 (YY1) plays a major role in the maintenance and progression of some pulmonary diseases, including pulmonary fibrosis. However, the role of YY1 in TB remains unknown. The aim of this study was to elucidate the role of YY1 in the regulation of CCL4 and its implication in TB. We determined whether YY1 regulates CCL4 using reporter plasmids, ChIP and siRNA assays. Immunohistochemistry and digital pathology were used to measure the expression of YY1 and CCL4 in a mouse model of TB. A retrospective comparison of patients with TB and control subjects was used to measure the expression of YY1 and CCL4 using tissue microarrays. Our results showed that YY1 regulates the transcription of CCL4; moreover, YY1, CCL4 and TGF-β were overexpressed in the lung tissues of mice with TB during the late stages of the disease and the tissues of TB patients. The expression of CCL4 and TGF-β correlated with YY1 expression. In conclusion, YY1 regulates CCL4 transcription; moreover, YY1 is overexpressed in experimental and human TB and is positively correlated with CCL4 and TGF-β expression. Therefore, treatments that decrease YY1 expression may be a new therapeutic strategy against TB.

Dual role of hypoxia-inducible factor 1 α in experimental pulmonary tuberculosis: its implication as a new therapeutic target

AIM Investigate the role of hypoxia-inducible factor-1α (HIF-1α) in pulmonary tuberculosis (TB). METHODS & RESULTS A model of progressive pulmonary TB in BALB/c mice, immunohistochemistry and digital pathology were used. High HIF-1α expression was observed during early TB in activated macrophages. During late TB, even higher HIF-1α expression was observed in foamy macrophages, which are resistant to apoptosis. Blocking HIF-1α during early infection with 2-methoxyestradiol worsened the disease, while during late TB, it induced macrophage apoptosis and decreased bacillary loads. CONCLUSION HIF-1α has a dual role in experimental TB. This finding could have therapeutic implications because combined treatment with 2-methoxyestradiol and antibiotics appeared to eliminate mycobacteria more efficiently than conventional chemotherapy during advanced disease.

Abstract 3374: BRAF and NRAS mutations in melanoma regulate the phosphorylation and inactivation of RKIP, the metastasis suppressor and immune surveillance cancer gene product

Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC The Raf Kinase Inhibitor Protein (RKIP) is a member of the phosphatidylethanolamine binding protein family (PEBP). RKIP binds to Raf-1 and prevents the activation of the ERK 1/2 cascade. RKIP expression is diminished in many primary cancers and is absent in many metastases. RKIP overexpression inhibits experimental metastases, hence, termed a metastasis suppressor. In addition, overexpression of RKIP reverses tumor cell resistance to drug-induced apoptosis, hence, termed an immune surveillance cancer gene product. Phosphorylation of RKIP (pRKIP) at Ser 153 by PKCs dissociates RKIP from Raf-1 (inactivating RKIP) and pRKIP binds to G-protein coupled receptor kinase 2 (GRK2, a kinase that inhibits G-protein coupled receptors (GPCRs) and resulting in the inhibition of GRK2 activity and stimulation of the ERK 1/2 activity. Over 90% of melanoma express oncogene mutations in BRAF and also express mutations in NRAS. Most of the transforming activity of these mutations results from the activation of MAPK. The roles of such mutations in the regulation of oncogenes involved in metastasis and resistance are not clear. The objective of this study was to initiate investigations on the roles of above mutations on the expression of RKIP and inactive pRKIP. We hypothesized that BRAF and NRAS mutations, through their activation of PKCs, will result in the phosphorylation and inactivation of RKIP and potentiation of ERK 1/2 activation, metastasis and drug resistance. In this study, we have examined a large panel of melanoma cell lines with no mutations and with BRAF and/or NRAS mutations using a Tissue microarray technology. The expression of both RKIP and pRKIP was examined and the evaluation of protein expression was performed by IHC and analyzed by blinded observers under light microscopy. While anti-RKIP antibody detects both RKIP and pRKIP, anti-pRKIP was specific for pRKIP. The mean intensities for the expression of each protein were determined using the software Image-ProPlus 6.3. In brief, five random fields of each cell line were evaluated at 400-magnification. From the IHC staining, general density expressions of each protein in the cell lines were measured in pixels/200 μm2. The data revealed that the majority (75%) of RKIP expression was in its phosphorylated form in cell lines with BRAF and NRAS mutations. These studies suggest that in melanoma cell lines with mutations, GRK2 is inactivated through its association with pRKIP and, thus, maintaining the activating signals mediated by GPCRs. Further, pRKIP expression may potentiate the metastatic potential and drug resistance. We propose that selective inhibitors of PKCs may elevate the expression of RKIP and result in the inhibition of the metastatic potential as well as in the sensitization of the tumor cells to subtoxic therapeutic drugs. These studies are currently being examined in our laboratories. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3374.