Redundant Signaling as the Predominant Mechanism for Resistance to Antibodies Targeting the Type-I Insulin-Like Growth Factor Receptor in Cells Derived from Childhood Sarcoma

Antibodies targeting insulin-like growth factor 1 receptor (IGF-1R) induce objective responses in only 5% to 15% of children with sarcoma. Understanding the mechanisms of resistance may identify combination therapies that optimize efficacy of IGF-1R-targeted antibodies. Sensitivity to the IGF-1R-targeting antibody TZ-1 was determined in rhabdomyosarcoma and Ewing sarcoma cell lines. Acquired resistance to TZ-1 was developed and characterized in sensitive Rh41 cells. The BRD4 inhibitor, JQ1, was evaluated as an agent to prevent acquired TZ-1 resistance in Rh41 cells. The phosphorylation status of receptor tyrosine kinases (RTK) was assessed. Sensitivity to TZ-1 in vivo was determined in Rh41 parental and TZ-1-resistant xenografts. Of 20 sarcoma cell lines, only Rh41 was sensitive to TZ-1. Cells intrinsically resistant to TZ-1 expressed multiple (>10) activated RTKs or a relatively less complex set of activated RTKs (∼5). TZ-1 decreased the phosphorylation of IGF-1R but had little effect on other phosphorylated RTKs in all resistant lines. TZ-1 rapidly induced activation of RTKs in Rh41 that was partially abrogated by knockdown of SOX18 and JQ1. Rh41/TZ-1 cells selected for acquired resistance to TZ-1 constitutively expressed multiple activated RTKs. TZ-1 treatment caused complete regressions in Rh41 xenografts and was significantly less effective against the Rh41/TZ-1 xenograft. Intrinsic resistance is a consequence of redundant signaling in pediatric sarcoma cell lines. Acquired resistance in Rh41 cells is associated with rapid induction of multiple RTKs, indicating a dynamic response to IGF-1R blockade and rapid development of resistance. The TZ-1 antibody had greater antitumor activity against Rh41 xenografts compared with other IGF-1R-targeted antibodies tested against this model.

IL-6 and CXCL8 mediate osteosarcoma-lung interactions critical to metastasis

Osteosarcoma (OS), a malignant tumor of bone, kills through aggressive metastatic spread almost exclusively to the lung. Mechanisms driving this tropism for lung tissue remain unknown, though likely invoke specific interactions between tumor cells and other cells within the lung metastatic niche. Aberrant overexpression of ΔNp63 in OS cells directly drives production of IL-6 and CXCL8. All these factors were expressed at higher levels in OS lung metastases than in matched primary tumors from the same patients. Expression in cell lines correlated strongly with lung colonization efficiency in murine xenograft models. Lentivirus-mediated expression endowed poorly metastatic OS cells with increased metastatic capacity. Disruption of IL-6 and CXCL8 signaling using genetic or pharmaceutical inhibitors had minimal effects on tumor cell proliferation in vitro or in vivo, but combination treatment inhibited metastasis across multiple models of metastatic OS. Strong interactions occurred between OS cells and both primary bronchial epithelial cells and bronchial smooth muscle cells that drove feed-forward amplification of IL-6 and CXCL8 production. These results identify IL-6 and CXCL8 as primary mediators of OS lung tropism and suggest pleiotropic, redundant mechanisms by which they might effect metastasis. Combination therapy studies demonstrate proof of concept for targeting these tumor-lung interactions to affect metastatic disease.

Verticillin A Inhibits Leiomyosarcoma and Malignant Peripheral Nerve Sheath Tumor Growth via Induction of Apoptosis

Objective

The heterogeneity of soft tissue sarcoma (STS) represents a major challenge for the development of effective therapeutics. Comprised of over 50 different histology subtypes of various etiologies, STS subsets are further characterized as either karyotypically simple or complex. Due to the number of genetic anomalies associated with genetically complex STS, development of therapies demonstrating potency against this STS cluster is especially challenging and yet greatly needed. Verticillin A is a small molecule natural product with demonstrated anticancer activity; however, the efficacy of this agent has never been evaluated in STS. Therefore, the goal of this study was to explore verticillin A as a potential STS therapeutic.

Methods

We performed survival (MTS) and clonogenic analyses to measure the impact of this agent on the viability and colony formation capability of karyotypically complex STS cell lines: malignant peripheral nerve sheath tumor (MPNST) and leiomyosarcoma (LMS). The in vitro effects of verticillin A on apoptosis were investigated through annexin V/PI flow cytometry analysis and by measuring fluorescently-labeled cleaved caspase 3/7 activity. The impact on cell cycle progression was assessed via cytometric measurement of propidium iodide intercalation. In vivo studies were performed using MPNST xenograft models. Tumors were processed and analyzed using immunohistochemistry (IHC) for verticillin A effects on growth (Ki67) and apoptosis (cleaved caspase 3).

Results

Treatment with verticillin A resulted in decreased STS growth and an increase in apoptotic levels after 24 h. 100 nM verticillin A induced significant cellular growth abrogation after 24 h (96.7, 88.7, 72.7, 57, and 39.7% reduction in LMS1, S462, ST88, SKLMS1, and MPNST724, respectively). We observed no arrest in cell cycle, elevated annexin, and a nearly two-fold increase in cleaved caspase 3/7 activity in all MPNST and LMS cell lines. Control normal human Schwann (HSC) and aortic smooth muscle (HASMC) cells displayed higher tolerance to verticillin A treatment compared to sarcoma cell lines, although toxicity was seen in HSC at the highest treatment dose. In vivo studies mirrored the in vitro results: by day 11, tumor size was significantly reduced in MPNST724 xenograft models with treatment of 0.25 and 0.5 mg/kg verticillin A. Additionally, IHC assessment of tumors demonstrated increased cleaved caspase 3 and decreased proliferation (Ki67) following treatment with verticillin A.

Conclusion

Advancement in the treatment of karyotypically complex STS is confounded by the high level of genetic abnormalities found in these diseases. Consequently, the identification and investigation of novel therapies is greatly needed. Our data suggest that verticillin A selectively inhibits MPNST and LMS growth via induction of apoptosis while exhibiting minimal to moderate effects on normal cells, pointing to verticillin A as a potential treatment for MPNST and LMS, after additional preclinical validation.

Abstract 2472: Mechanisms of resistance to IGFR-targeted therapy in pediatric sarcomas

Background: Insulin-like growth factor-I receptor (IGFR) signaling promotes tumorigenic properties which makes targeting IGFR an attractive therapeutic target. IGF signaling has been linked to proliferation, survival, angiogenesis, metastasis and resistance to anticancer therapies, and contributes to pediatric malignancies including Ewing sarcoma and rhabdomyosarcoma. Recently, monoclonal antibodies targeting IGFR have shown promise in a limited number of sarcoma patients. A substantial proportion of patients demonstrate intrinsic resistance, and those that do respond will often lose clinical benefit (acquired resistance). Intrinsic and acquired resistance ultimately results in failure to respond to treatment and continued growth of the tumor. Understanding these resistance mechanisms will identify combinations of targeted therapy to optimize therapeutic efficiency of this targeted agent.

Methods: To test intrinsic and acquired mechanisms of resistance, we utilized Receptor Tyrosine Kinase (RTK) Arrays to analyze the phosphorylation status of 49 RTKs. For intrinsic resistance, we used a panel of Ewing Sarcoma (EWS) cell lines that are unresponsive to TZ1, a monoclonal antibody that targets IGFR. For acquired resistance, we developed a TZ1 resistant rhabdomyosarcoma (RMS) cell line from TZ1 sensitive RH41 cells. The cell lines were treated with TZ1, an anti-IGFR monoclonal antibody. Signaling changes were assessed by comparing phosphorylation status of the RTKs in the untreated versus treated cells in the inherent resistance model and in the parental versus resistant cells in the acquired resistance model. Results: TZ-1 treatment of the EWS cell lines with intrinsic resistance decreased pIGFR, but these cells were characterized by expression of multiple phosphorylated RTKs. In the Rh41 acquired resistance model, increased activation of signaling pathways was detected in the resistance cells including: AXL, PDGFR, FGFR4 and ALK. Treatment of parental Rh41 cells with TZ1 also rapidly induced several activated RTKs. In TZ1-resistant Rh41 cells combined treatment of TZ1 with the PDGFR inhibitor, crenolanib, and the pan-FGFR inhibitor LY2874455 resulted in significant decrease in cellular proliferation.

Conclusions: Intrinsic resistance to TZ1 in EWS cell lines appears to be due to redundancy through multiple alternative activated RTKs. Systematic knockdown to determine which activated RTKs confer resistance is being undertaken. In Rh41 RMS cells acquired resistance to TZ1 is characterized by induction of several alternative activated RTKs, some of which are induced rapidly after TZ1 exposure. Combined treatment with TZ1 and drugs targeting PDGFR and FGFR was effective at overcoming resistance. These results suggest that identification of signaling pathways that compensate for IGFR inhibition can lead to effective potent multi-target combination therapy. Supported by USPHS Grant CA165995.

Citation Format: Terry J. Shackleford, Seethalakshmi Hariharan, Hemant K. Bid, Peter J. Houghton. Mechanisms of resistance to IGFR-targeted therapy in pediatric sarcomas. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2472.

Abstract LB-036: Elevated STAT3 expression in ovarian tumor ascites regulates invasion and metastasis: a promising therapeutic target

Objectives: Although, the ovarian cancer patient ascites is a recognized source of metastasis, the expression of oncogenic proteins in ascites and their effects on the tumor metastatic microenvironment still remain poorly understood. In this study, we investigate the role of STAT3 in primary ovarian cancer ascites and STAT3 as a potential target for ovarian tumor therapy in a preclinical animal model using our novel and safe STAT3 inhibitor of HO-3867.

Methods: We start with culturing the primary cancer cell lines from various human ascites and confirming the status of STAT3 signaling. The exact role that STAT3 plays in ovarian cancer was addressed using STAT3 knocked down and STAT3 overexpression cell lines. These were further used to develop an orthotopic mouse model of ovarian cancer. In vivo antitumor activity of STAT3 inhibitor of HO-3867 assessment was done by oral administration of HO-3867 in orthotopic tumor mice. using histopathological analysis, RPPA, TUNEL and angiogenesis assays. In vivo bio-absorption of HO-3867 compounds in tumors by EPR and LCMS analysis.

Results: We have found that pSTAT3 Tyr705 is constitutively expressed in the patient ascites derived cancer cells (ADCCs) and the range of expression could be very high to low. Subsequent in vivo transplantation of ADCCs with higher pSTAT3 expression injected into mice resulted in a large primary tumor and widespread metastases; while the mice with cells with STAT3 Knocked out had a smaller tumor and no metastases. We further demonstrate that the cytokines secreted into the culture medium can activate the JAK/STAT pathway in the STAT3 Ko cells thereby making up for the absence of inherent STAT3 in the cells. Once we proved the importance of STAT3 in ovarian cancer progression and metastases, we moved on to targeting STAT3 using our novel STAT3 inhibitor and pre-clinical orthotopic tumor model. Treatment with HO-3867 (100 ppm) significantly suppressed ovarian tumor growth and metastasis. A substantial amount of HO-3867 was detected in the ovarian tumor tissues. Suppression of STAT3 and its downstream target proteins were confirmed with reverse phase protein array. In vivo Matrigel assay showed that HO-3867 treated samples had significantly reduced vessel formation (∼4 times) when compared to untreated control. HO-3867 was also found to have cytotoxic effects in ex vivo culture of freshly collected human tumor samples, including patients with chemotherapy-resistant disease.

Conclusions: Our study has concluded that constitutive expression of STAT3 in patient ascites is a significant contributor in ovarian tumor invasion and metastasis. STAT3-selective targeting agent HO-3867 in orthotopic ovarian tumor and ex vivo tumor tissue culture, results in inhibition of tumor growth and induction of apoptosis both in vivo and ex vivo, suggesting that HO-3867 is an exciting new cytotoxic agent acting through targeting STAT3; which could have a considerable role in the future treatment of ovarian cancer.

Citation Format: Uksha Saini, Shan Naidu, Adam C. ElNaggar, Hemant K. Bid, John Wallbillich, Ross Wanner, Kristin Bixel, Maria Riley, Chelsea Bolyard, Adrian A. Suarez, Balveen Kaur, Periannan Kuppusamy, John Hays, Paul Goodfellow, David E. Cohn, Karuppaiyah Selvendiran. Elevated STAT3 expression in ovarian tumor ascites regulates invasion and metastasis: a promising therapeutic target. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-036.

Abstract B40: Autocrine and paracrine IL-6 and IL-8 drive osteosarcoma lung tropism and facilitate metastasis

Osteosarcoma originates in bone, but metastasizes predictably to the lungs. Patients who develop lung metastases become much more difficult to treat. Metastatic lung disease responds poorly to traditional chemotherapy. We know very little of the mechanisms that mediate this lung tropism, or predilection for spread to lung tissue. A better understanding of this process could facilitate disruption of pathways which drive the metastatic process, potentially preventing or even treating lung metastasis. We thus sought to identify tumor-lung interactions that facilitate extravasation, survival, and growth of tumor cells specifically within the lung environment.

Drawing on published signatures of osteosarcoma metastasis, we curated a list of 59 candidate genes that might facilitate lung metastasis. By comparing expression in metastatic lung lesions relative to paired primary tumors, we found that metastatic tumors reliably express two cytokines, IL-6 and IL-8, at much higher levels than matched primary bone tumors. In a mouse model of osteosarcoma, we found that tumors expressing high levels of autocrine IL-6 and IL-8 established lung metastases much more readily than tumors which expressed low or no IL-6 or IL-8.

Using immunohistochemistry to identify sources of these cytokines within human metastatic lesions, we found higher levels of IL-6 and IL-8 coming from non-malignant cells within the tumor, especially mononuclear infiltrates and peri-bronchiolar cells. Modelling tumor-lung interactions in vitro using a co-culture system, much higher levels of IL-6 and IL-8 were produced when osteosarcoma cells were cultured with bronchial epithelial cells, smooth muscle cells, or macrophages suggesting that paracrine interactions drive production of these cytokines upon interaction of tumor cells with resident lung cells. In murine models of osteosarcoma metastasis, blocking IL-6 and/or IL-8 production within tumor cells using inducible shRNA-expressing lentiviruses dramatically reduced metastatic efficiency.

Our data suggest that IL-6 and IL-8 play a primary role in the development of osteosarcoma lung metastasis. The readily targetable nature of these pathways makes them attractive candidates for therapies designed to prevent and possibly treat osteosarcoma lung metastasis.

Citation Format: Ryan D. Roberts, Amy C. Gross, Hemant K. Bid, Doris Phelps, Mary F. Wedekind, Peter J. Houghton. Autocrine and paracrine IL-6 and IL-8 drive osteosarcoma lung tropism and facilitate metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B40.

The Bromodomain BET Inhibitor JQ1 Suppresses Tumor Angiogenesis in Models of Childhood Sarcoma

The bromodomain and extra-terminal domain inhibitor JQ1 has marked antitumor activity against several hematologic malignancies as well as solid tumor models. Here, we investigated its activity in vitro and in vivo against models of childhood rhabdomyosarcoma and Ewing sarcoma. In vitro, JQ1 (but not the inactive enantiomer JQ1R) inhibited cell proliferation and increased G1 fraction of cells, although there was no correlation between cell line sensitivity and suppression of c-MYC or MYCN. In vivo, xenografts showed significant inhibition of growth during the period of treatment, and rapid regrowth after treatment was stopped, activity typical of antiangiogenic agents. Furthermore, xenografts derived from cell lines intrinsically resistant or sensitive to JQ1 in vitro had similar sensitivity in vivo as xenografts. Further investigation showed that JQ1 reduced tumor vascularization. This was secondary to both drug-induced downregulation of tumor-derived growth factors and direct effects of JQ1 on vascular elements. JQ1 suppressed VEGF-stimulated vascularization of Matrigel plugs in mice, and in vitro suppressed differentiation, proliferation, and invasion of human umbilical cord vascular endothelial cells (HUVEC). In HUVECs, JQ1 partially suppressed c-MYC levels, but dramatically reduced AP-1 levels and activity through suppression of the AP-1-associated protein FOSL1. Our data suggest that the antitumor activity of JQ1 in these sarcoma models is largely a consequence of its antiangiogenic activity. Mol Cancer Ther; 15(5); 1018-28. ©2016 AACR.

Abstract 1720: HO-3867, a selective inhibitor of stat3, suppress ovarian tumor growth and metastasis in human tissue culture and in an orthotopic mouse model

The lack of an efficient pre-clinical model predicting a drug's clinical response before it enters into clinical trials is a major reason behind the limited success or complete failure of most of the traditional anti-cancer compounds. In this study, we evaluate our novel, safe and selective STAT3 inhibitor HO-3867 for its anti-cancer efficacy/bio-availability using a pre-clinical relevant, orthotopic ovarian tumor model and ex-vivo human tumor tissue culture. Treatment with HO-3867 (100PPM) significantly suppressed ovarian tumor growth and metastasis when compared to the standard Cisplatin (4mg/kg). A substantial amount of HO-3867 was detected in the ovarian tumor tissues and quantified using EPR spectroscopy. Markers specific to cell proliferation (Ki-67, Cyclin D1), angiogenesis (VEGF and Kinase array) and apoptosis (caspase-3 activity) were significantly altered by treatment with HO-3867. In vivo histopathological evaluation of internal organs collected from treated tumor mice revealed no evidence of toxicity specific to HO-3867. Normal and malignant tissues were collected and TUNEL/8-OHdG staining revealed selective induction of apoptosis limited to neoplastic cells and concomitant increase in reactive oxygen species within the orthotopic tumor. Suppression of STAT3 and its downstream target proteins (cell proliferative, anti-apoptotic and angiogenic) was confirmed with proteomic array. HO-3867 treated samples had significantly reduced vessel formation (∼4 times) as compared to the untreated control as is evident by in vivo Matrigel assay. HO-3867 was also found to have cytotoxic effects in ex vivo culture of freshly collected human tumor samples, including patients with chemotherapy resistant form of the disease. Overall, these results highlight the clinical anti-cancer potential of HO-3867 using a relevant preclinical orthotopic ovarian tumor model, and provide a rationale for the inclusion of ex vivo patient tumor slice culture in oncologic drug development processes.

Citation Format: Shan Naidu, Uksha Saini, Adam C. ElNaggar, Hemant K. Bid, Ross Wanner, Kristin Bixel, Adrian A. Suarez, Chelsea Bolyard, Balveen Kaur, Paul J. Goodfellow, Periannan Kuppusamy, David Cohn, Karuppaiyah Selvendiran. HO-3867, a selective inhibitor of stat3, suppress ovarian tumor growth and metastasis in human tissue culture and in an orthotopic mouse model. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1720. doi:10.1158/1538-7445.AM2015-1720

Detection and biological activities of carboxyethylpyrrole ethanolamine phospholipids (CEP-EPs)

Oxidation of docosahexaenoate phospholipids produces 4-hydroxy-7-oxo-hept-5-eonyl phospholipids (HOHA-PLs) that react with protein lysyl ε-amino residues to generate 2-ω-carboxyethylpyrrole (CEP) derivatives, endogenous factors that induce angiogenesis in the retina and tumors. It seemed likely, but remained unproven, that HOHA-PLs react with ethanolamine phospholipids (EPs) in vivo to generate CEP-EPs. We now show that CEP-EPs are present in human blood at 4.6-fold higher levels in age-related macular degeneration plasma than in normal plasma. We also show that CEP-EPs are pro-angiogenic, inducing tube formation by human umbilical vein endothelial cells by activating Toll-like receptor 2. CEP-EP levels may be a useful biomarker for clinical assessment of AMD risk and CEP-associated tumor progression and a tool for monitoring the efficacy of therapeutic interventions.

Abstract A45: Autocrine and paracrine IL-6 and IL-8 drive osteosarcoma metastasis

For patients with most types of solid tumors, metastases drive the morbidity and mortality of their disease. For patients with osteosarcoma this is particularly true, with metastases that occur almost exclusively within the lung. We set out to identify the factors that facilitate growth of osteosarcoma specifically within the lung environment. To do this, we identified a set of candidate genes and tested them for reliably enriched levels of expression in metastatic lesions relative to primary tumors in the same patients. IL-6 and IL-8 are among the most reliably enriched genes in the metastatic lesions. Osteosarcoma cell lines that express high-levels of IL-6 and IL-8 not only respond to these signals in an autocrine manner, but form lung metastases much more readily than cell lines with low IL-6 and IL-8 expression in mouse xenograft models. IL-6 and IL-8 drive chemokinesis, directional migration, and invasive activity in osteosarcoma cells independent of the degree to which they express these cytokines. Blocking IL-6 and IL-8 signals reduces the metastatic efficiency of osteosarcoma cells. These data suggest that IL-6 and IL-8 play a central role in the mechanisms that account for lung tropism in osteosarcoma and provide attractive targets for therapies intended to prevent metastasis in order to improve outcomes in patients with osteosarcoma.

Citation Format: Ryan D. Roberts, Hemant K. Bid, Doris Phelps, Brett W. Hendrickson, Hakan Cam, Peter J. Houghton. Autocrine and paracrine IL-6 and IL-8 drive osteosarcoma metastasis. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A45.

Abstract 2775: Development and characterization of a MEK1 inhibitor (AZD6244) sensitive childhood astrocytoma cell line

We previously characterized the development and reversal of acquired resistance to the MEK1 inhibitor AZD6244 in an in vivo model of childhood astrocytoma. The BT-40 astrocytoma xenograft model expresses mutated BRAFV600E and is highly sensitive to AZD6244, but acquires resistance, which can be overcome with the addition of the STAT3 inhibitor LLL12. The purpose of this current study was to establish and characterize a cell line derived from the xenograft model as well as develop an orthotopic mouse model. Sensitivity to AZD6244 and LLL12, expression-profiling assessment of MEK signature and compensatory pathways, and cytokine levels were assessed in the newly developed BT-40 cell line. The BT-40 cell line exhibited sensitivity to AZD6244 and LLL12 with IC50 values of 350nM and 1µM, respectively. Combination treatment was additive. Treatment of the cells with AZD6244 inhibited p-Erk and the mTOR downstream signaling molecule p-S6, while p-Akt, p-STAT3, p-4E-BP1 increased. Kinase expression arrays performed on cells treated with AZD6244 displayed a decrease in IL-1α, G-CSF, and IL-6 and an increase in CXCL10. The decrease in IL-6 was restored to baseline levels with the addition of LLL12. Interestingly, the JAK2 inhibitor AZD1480 failed to restore the IL-6 levels. The IL-6 results observed in the expression arrays were confirmed by ELISA, where AZD6244 decreased soluble IL-6 levels and LLL12, but not AZD1480, restored IL-6 levels to baseline. The BT-40 cell line, along with a cell line stably expressing luciferase (BT-40Luc), were implanted into the caudate putamen using stereotaxic guidance. The BT-40Luc cells exhibited exponential growth over time as evaluated with bioluminescent imaging. In conclusion, a cell line derived from a previously described in vivo model of childhood astrocytoma was developed that closely recapitulated our original findings in the xenograft model following treatment with the MEK1 inhibitor AZD6244. Furthermore, an orthotopic model of these cells was developed, which will allow us to characterize response to established and novel therapeutic agents. Supported by PHS award CA169368.

Citation Format: Adam W. Studebaker, Hemant K. Bid, Doris A. Phelps, Peter J. Houghton. Development and characterization of a MEK1 inhibitor (AZD6244) sensitive childhood astrocytoma cell line. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2775. doi:10.1158/1538-7445.AM2014-2775

Targeting constitutively-activated STAT3 in hypoxic ovarian cancer, using a novel STAT3 inhibitor

Tumor hypoxia, a feature of many solid tumors including ovarian cancer, is associated with resistance to therapies. We previously demonstrated that hypoxic exposure results in increased expression of phosphorylated signal transducer and activator of transcription 3 (pSTAT3). We hypothesized the activation of STAT3 could lead to chemotherapeutic resistance in ovarian cancer cells in hypoxic conditions. In this study, we demonstrate the level of pSTAT3 Tyr705 is increased in the hypoxic regions of human epithelial ovarian cancer (EOC) specimens, as determined by HIF-1α and CD-31 staining. In vitro mutagenesis studies proved that pSTAT3 Tyr705 is necessary for cell survival and proliferation under hypoxic conditions. In addition, we show that S1PR1, a regulator of STAT3 transcription via the JAK/STAT pathway, is highly expressed in hypoxic ovarian cancer cells (HOCCs). Knock down of S1PR1 in HOCCs reduced pSTAT3 Tyr705 levels and was associated with decreased cell survival. Treatment of HOCCs with the STAT3 inhibitor HO-3867 resulted in a rapid and dramatic decrease in pSTAT3 Tyr705 levels as a result of ubiquitin proteasome degradation. STAT3-target proteins Bcl-xL, cyclin D2 and VEGF showed similar decreases in HO-3867 treated cells. Taken together, these findings suggest that activation of STAT3 Tyr705 promotes cell survival and proliferation in HOCCs, and that S1PR1 is involved in the initiation of STAT3 activation. Targeting hypoxia-mediated STAT3 activation represents a therapeutic option for ovarian cancer and other solid tumors.

HO-3867, a safe STAT3 inhibitor, is selectively cytotoxic to ovarian cancer

STAT3 is well corroborated preclinically as a cancer therapeutic target, but tractable translational strategies for its blockade by small molecule inhibitors have remained elusive. In this study, we report the development of a novel class of bifunctional STAT3 inhibitors, based on conjugation of a diarylidenyl-piperidone (DAP) backbone to an N-hydroxypyrroline (-NOH) group, which exhibits minimal toxicity against normal cells and good oral bioavailability. Molecular modeling studies of this class suggested direct interaction with the STAT3 DNA binding domain. In particular, the DAP compound HO-3867 selectively inhibited STAT3 phosphorylation, transcription, and DNA binding without affecting the expression of other active STATs. HO-3867 exhibited minimal toxicity toward noncancerous cells and tissues but induced apoptosis in ovarian cancer cells. Pharmacologic analysis revealed greater bioabsorption and bioavailability of the active (cytotoxic) metabolites in cancer cells compared with normal cells. The selective cytotoxicity of HO-3867 seemed to be multifaceted, eliciting differential activation of the Akt pathway in normal versus cancer cells. RNAi attenuation experiments confirmed the requirement of STAT3 for HO-3867-mediated apoptosis in ovarian cancer cells. In vivo testing showed that HO-3867 could block xenograft tumor growth without toxic side effects. Furthermore, in primary human ovarian cancer cells isolated from patient ascites, HO-3867 inhibited cell migration/invasion and survival. Our results offer preclinical proof-of-concept for HO-3867 as a selective STAT3 inhibitor to treat ovarian cancer and other solid tumors where STAT3 is widely upregulated.

p53/TAp63 and AKT regulate mammalian target of rapamycin complex 1 (mTORC1) signaling through two independent parallel pathways in the presence of DNA damage

Under conditions of DNA damage, the mammalian target of rapamycin complex 1 (mTORC1) is inhibited, preventing cell cycle progression and conserving cellular energy by suppressing translation. We show that suppression of mTORC1 signaling to 4E-BP1 requires the coordinated activity of two tumor suppressors, p53 and p63. In contrast, suppression of S6K1 and ribosomal protein S6 phosphorylation by DNA damage is Akt-dependent. We find that loss of either p53, required for the induction of Sestrin 1/2, or p63, required for the induction of REDD1 and activation of the tuberous sclerosis complex, prevents the DNA damage-induced suppression of mTORC1 signaling. These data indicate that the negative regulation of cap-dependent translation by mTORC1 inhibition subsequent to DNA damage is abrogated in most human cancers.

ΔNp63 promotes pediatric neuroblastoma and osteosarcoma by regulating tumor angiogenesis

The tumor suppressor gene p53 and its family members p63/p73 are critical determinants of tumorigenesis. ΔNp63 is a splice variant of p63, which lacks the N-terminal transactivation domain. It is thought to antagonize p53-, p63-, and p73-dependent translation, thus blocking their tumor suppressor activity. In our studies of the pediatric solid tumors neuroblastoma and osteosarcoma, we find overexpression of ΔNp63; however, there is no correlation of ΔNp63 expression with p53 mutation status. Our data suggest that ΔNp63 itself endows cells with a gain-of-function that leads to malignant transformation, a function independent of any p53 antagonism. Here, we demonstrate that ΔNp63 overexpression, independent of p53, increases secretion of interleukin (IL)-6 and IL-8, leading to elevated phosphorylation of STAT3 (Tyr-705). We show that elevated phosphorylation of STAT3 leads to stabilization of hypoxia-inducible factor 1α (HIF-1α) protein, resulting in VEGF secretion. We also show human clinical data, which suggest a mechanistic role for ΔNp63 in osteosarcoma metastasis. In summary, our studies reveal the mechanism by which ΔNp63, as a master transcription factor, modulates tumor angiogenesis.

Development, characterization, and reversal of acquired resistance to the MEK1 inhibitor selumetinib (AZD6244) in an in vivo model of childhood astrocytoma

PURPOSE

The BT-40 low-grade childhood astrocytoma xenograft model expresses mutated BRAF(V600E) and is highly sensitive to the MEK inhibitor selumetinib (AZD6244). In this study, we developed and characterized selumetinib resistance and explored approaches to circumventing the mechanisms of acquired resistance.

EXPERIMENTAL DESIGN

BT-40 xenografts were selected in vivo for selumetinib resistance. Resistant tumors were obtained and characterized, as were tumors that reverted to sensitivity. Characterization included expression profiling, assessment of MEK signature and compensatory pathways, MEK inhibition, BRAF expression, and cytokine levels. Combination treatment of BT-40/AZD-resistant tumors with the MEK inhibitor and a STAT3 inhibitor (LLL12) was assessed.

RESULTS

Resistance was unstable, tumors reverting to selumetinib sensitivity when passaged in untreated mice, and MEK was equally inhibited in sensitive and resistant tumors by selumetinib. Drug resistance was associated with an enhanced MEK signature and increased interleukin (IL)-6 and IL-8 expression. Selumetinib treatment induced phosphorylation of STAT3 (Y705) only in resistant xenografts, and similar results were observed in BRAF(V600E) astrocytic cell lines intrinsically resistant to selumetinib. Treatment of BT-40-resistant tumors with selumetinib or LLL12 had no significant effect, whereas combined treatment induced complete regressions of BT-40/AZD-resistant xenografts.

CONCLUSIONS

Resistance to selumetinib selected in vivo in BT-40 tumor xenografts was unstable. In resistant tumors, selumetinib activated STAT3, and combined treatment with selumetinib and LLL12 induced complete responses in resistant BT-40 tumors. These results suggest dual targeting BRAF (V600E) signaling and STAT3 signaling may be effective in selumetinib-resistant tumors or may retard or prevent onset of resistance.

RAC1: an emerging therapeutic option for targeting cancer angiogenesis and metastasis

Angiogenesis and metastasis are well recognized as processes fundamental to the development of malignancy. Both processes involve the coordination of multiple cellular and chemical activities through myriad signaling networks, providing a mass of potential targets for therapeutic intervention. This review will focus on one master regulator of cell motility, RAC1, and the existing data with regard to its role in cell motility, including particular roles for tumor angiogenesis and invasion/metastasis. We also emphasize the preclinical investigations carried out with RAC1 inhibitors to evaluate the therapeutic potential of this target. Herein, we explore potential future directions as well as the challenges of targeting RAC1 in the treatment of cancer. Recent insights at the molecular and cellular levels are paving the way for a more directed and detailed approach to target mechanisms of RAC1 regulating angiogenesis and metastasis. Understanding these mechanisms may provide insight into RAC1 signaling components as alternative therapeutic targets for tumor angiogenesis and metastasis.

Abstract 2753: Targeting bromodomain and extra-terminal (BET) family member BRD4 for treatment of pediatric sarcomas

Background. Potent inhibitors of histone binding modules have the potential to suppress, selectively, transcription of specific genes, including MYC family of transcription factors. JQ1 binds competitively to acetyl-lysine recognition motifs, or bromodomains. JQ1 inhibits BET bromodomain, and down-regulates MYC transcription. Ewing sarcoma (EWS) and alveolar rhabdomyosarcoma (ARMS) are associated with high expression of c-MYC and MYCN, respectively (Delmore JE, Cell 2011; Filippakopoulos P, Nature 2010). Consequently, we have evaluated sensitivity of EWS and ARMS cell lines and xenograft models to JQ1.

Methods. EWS and ARMS cells were incubated with JQ1, or JQ1R (non-active enantiomer) for 96 hrs. Cell viability was determined by Alamar Blue staining. C-MYC and MYCN were determined by immunoblotting. Xenograft tumor lines were grown in CB17 female SCID mice. JQ1 was administered P.O. at 30 mg/kg (BID) or 50 mg/kg (SID) for up to 3 weeks. Assessment of JQ1 activity was as described (Houghton P, Ped Blood & Cancer, 2007). The effect of JQ1 on proliferation and tube formation of human umbilical vascular endothelial cells (HUVECs) was as described (Bid H, Mol Cancer Ther, 2012).

Results. For all cell lines, the IC50 concentration for JQ1R (inactive enantiomer) was > 10 microM. EWS cell lines (n=9) segregated into two distinct groups with IC50 < 1 microM, (ES-1, ES-2, ES-3, ES-4, ES-7, ES-8) and cell lines with significantly higher IC50s (IC50 > 7 microM ES-6, EW8, CHLA-258). Seven of 9 ARMS cell lines demonstrated sensitivity to JQ1 (IC50 < 1 microM) whereas 2 lines were insensitive (IC50 > 10 microM Rh18, Rh30). JQ1 (500 nM, 24 hr) markedly down-regulated c-MYC in Rh41, and to a lesser extent in Rh36. MYCN expression in Rh5 ARMS cell line was also suppressed by JQ1. Of interest, JQ1 did not suppress c-MYC in any EWS cell line. In vivo, BID and SID dosing was well tolerated (mortality 1.2%) and gave similar antitumor activity. JQ1 significantly retarded growth of all 4 sarcoma models (Rh10, Rh28 ARMS and EW5, EW8 EWS lines. T/C at day 21 range 0.30 – 0.43). Of note, while EW8 cells in vitro were resistant to JQ1 (IC50 > 10 microM), the xenografts were equally sensitive as other lines to JQ1 treatment, suggesting JQ1 exerted effects on stroma/angiogenesis. In vitro, JQ1 (500 nM) suppressed tube formation of HUVECs without decreasing viability.

Conclusions. JQ1 potently inhibited proliferation of EWS and ARMS cells in vitro, with distinct groups demonstrating either sensitivity or resistance. Sensitivity was associated with decreased levels of MYCN or c-MYC in some cell lines. In vivo, JQ1 demonstrated significant antitumor activity in 4 xenograft lines, including EW8 derived from cells resistant to JQ1 in vitro. The potential for JQ1 to exert anti-angiogenic effects is suggested by its potent inhibition of HUVECs differentiation. Supported through a grant from SWOG

Citation Format: Linlin Xiao, Doris A. Phelps, Laurence A. Baker, Jun Qi, Hemant K. Bid, Peter J. Houghton. Targeting bromodomain and extra-terminal (BET) family member BRD4 for treatment of pediatric sarcomas. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2753. doi:10.1158/1538-7445.AM2013-2753

Abstract 2308: ΔNp63 promotes neuroblastoma by regulating tumor angiogenesis

Background: The tumor suppressor gene p63 and its family members p53/p73 have been described as critical determinants of tumorigenesis. ΔNp63, a splice variant of p63 lacking the N-terminal transactivation domain, is thought to antagonize the transcriptional regulation of the p53, p63 and p73 target genes and blocks their tumor suppressor activity. Overexpression of ΔNp63 has been observed in a number of adult human cancers, suggesting a role of this isoform in tumor formation. While some studies have proposed that ΔNp63 might simply inhibit p53 function within cells, leading to malignant transformation, we found that this model is challenged by the lack of consistent correlation between p53 mutation and ΔNp63 expression suggesting that ΔNp63 might possess a gain of function.

Methods: Since expression of ΔNp63 isoforms in primary tumors has been shown to correlate with poor prognosis, we attempted to analyze their relationships with tumor angiogenesis. To test whether overexpression of oncogenic ΔNp63 in HEK-293T cells can stimulate tube formation in endothelial cells using HUVEC tube formation assay. Further, we performed gene affymetrix as well as protein micro array analysis in primary cells compared to cells overexpressed ΔNp63 isoforms. In addition, we used siRNA techniques to verify any potential role of ΔNp63 isoforms in tumor angiogenesis in vitro as well as in vivo experiments.

Results: We found that overexpression of the oncogenic isoform of p53 family member ΔNp63 in HEK-293T cells resulted in stimulation of tubular structures in HUVEC cells. As 293T cells lack functional p53, these results strongly suggest a gain of function for ΔNp63. In addition, we found that ΔNp63 is overexpressed in neuroblastoma and ΔNp63 overexpression results in increasing secretion of the inflammatory cytokines interleukin-6 (IL-6) and -8 (IL-8) leading to elevated phosphorylation of STAT-3. Our further analysis showed that elevated phosphorylation of STAT-3 induced stabilization of HIF-1α protein resulting in VEGF secretion.

Conclusions: We found that ΔNp63 is overexpressed in neuroblastoma and resulted in elevated secretion of the inflammatory cytokines IL-6 and -8 leading to increased STAT3 activation. Our further studies showed that elevated ΔNp63 induced stabilization of HIF-1α protein resulting in VEGF secretion in a p53 independent manner. Importantly, we show in vitro and in vivo experiments that depletion of ΔNp63 isoform by specific siRNAs significantly reduced angiogenic potential of Neuroblastoma. In summary, our study revealed the underlying molecular mechanism how ΔNp63, as a master transcription factor, modulates tumor angiogenesis in Neuroblastoma.

Citation Format: Hemant K. Bid, Maren Cam, Antony Audino, Raushan Kurmasheva, Jiayuh Lin, Peter Houghton, Hakan Cam. ΔNp63 promotes neuroblastoma by regulating tumor angiogenesis. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2308. doi:10.1158/1538-7445.AM2013-2308

Dual targeting of the type 1 insulin-like growth factor receptor and its ligands as an effective antiangiogenic strategy

BACKGROUND

In pediatric tumor xenograft models, tumor-derived insulin growth factor (IGF-2) results in intrinsic resistance to IGF-IR-targeted antibodies, maintaining continued tumor angiogenesis. We evaluated the antiangiogenic activity of a ligand-binding antibody (MEDI-573) alone or in combination with IGF-I receptor binding antibodies (MAB391, CP01-B02).

METHODS

IGF-stimulated signaling was monitored by increased Akt phosphorylation in sarcoma and human umbilical cord vascular endothelial cells (HUVEC). Angiogenesis was determined in vitro using capillary tube formation in HUVECs and in vivo using a VEGF-stimulated Matrigel assay. Tumor growth delay was examined in 4 sarcoma xenograft models.

RESULTS

The IGF ligand-binding antibody MEDI-573 suppressed Akt phosphorylation induced by exogenous IGF-I and IGF-2 in sarcoma cells. Receptor-binding antibodies suppressed IGF-I stimulation of Akt phosphorylation, but IGF-2 circumvented this effect and maintained HUVEC tube formation. MEDI-573 inhibited HUVEC proliferation and tube formation in vitro, but did not inhibit angiogenesis in vivo, probably because MEDI-573 binds murine IGF-I with low affinity. However, in vitro antiangiogenic activity of MEDI-573 was also circumvented by human recombinant IGF-I. The combination of receptor- and ligand-binding antibodies completely suppressed VEGF-stimulated proliferation of HUVECs in the presence of IGF-I and IGF-2, prevented ligand-induced phosphorylation of IGF-IR/IR receptors, and suppressed VEGF/IGF-2-driven angiogenesis in vivo. The combination of CP1-BO2 plus MEDI-573 was significantly superior to therapy with either antibody alone against IGF-I and IGF-2 secreting pediatric sarcoma xenograft models.

CONCLUSIONS

These results suggest that combination of antibodies targeting IGF receptor and ligands may be an effective therapeutic strategy to block angiogenesis for IGF-driven tumors.

Vitamin D receptor as a therapeutic target for benign prostatic hyperplasia

The bioactive form of vitamin D, 1α, 25-dihydroxyvitamin D3 (1α, 25(OH)2D3), is a secosteroid hormone that binds to the vitamin D receptor (VDR), a member of the nuclear receptor super-family expressed in many cell types, and modulates a variety of biological functions. 1α, 25(OH)2D3 is essential for bone and mineral homeostasis, but also regulates growth and differentiation of multiple cell types, and displays immunoregulatory and anti-inflammatory activities. The antiproliferative, prodifferentiative, antibacterial, immunomodulatory and anti-inflammatory properties of synthetic VDR agonists could be exploited to treat a variety of chronic inflammatory and autoimmune diseases, including benign prostatic hyperplasia (BPH). It has been hypothesized that VDR may influence both the risk of a variety of diseases and their occurrence and prognosis. However, earlier studies investigating the associations between specific VDR polymorphisms and various diseases often show controversial results. We performed a systematic review of the current literature on vitamin D and BPH using the PubMed and Web of Knowledge databases. The aim of this review is to summarize the current knowledge on the utility of the VDR gene regarding prostate growth as well as the pathogenesis and treatment of BPH, a complex syndrome characterized by a static component related to prostate overgrowth, a dynamic component responsible for urinary storage symptoms, and an inflammatory component. Despite the massive advances in recent decades, further research is needed to fully characterize the exact underlying mechanisms of VDR action on BPH and to comprehend how these cellular changes translate into clinical development in physical concert.

Anti-tumor activity of a novel HS-mimetic-vascular endothelial growth factor binding small molecule

The angiogenic process is controlled by variety of factors of which the vascular endothelial growth factor (VEGF) pathway plays a major role. A series of heparan sulfate mimetic small molecules targeting VEGF/VEGFR pathway has been synthesized. Among them, compound 8 (2-butyl-5-chloro-3-(4-nitro-benzyl)-3H-imidazole-4-carbaldehyde) was identified as a significant binding molecule for the heparin-binding domain of VEGF, determined by high-throughput-surface plasmon resonance assay. The data predicted strong binding of compound 8 with VEGF which may prevent the binding of VEGF to its receptor. We compared the structure of compound 8 with heparan sulfate (HS), which have in common the functional ionic groups such as sulfate, nitro and carbaldehyde that can be located in similar positions of the disaccharide structure of HS. Molecular docking studies predicted that compound 8 binds at the heparin binding domain of VEGF through strong hydrogen bonding with Lys-30 and Gln-20 amino acid residues, and consistent with the prediction, compound 8 inhibited binding of VEGF to immobilized heparin. In vitro studies showed that compound 8 inhibits the VEGF-induced proliferation migration and tube formation of mouse vascular endothelial cells, and finally the invasion of a murine osteosarcoma cell line (LM8G7) which secrets high levels of VEGF. In vivo, these effects produce significant decrease of tumor burden in an experimental model of liver metastasis. Collectively, these data indicate that compound 8 may prevent tumor growth through a direct effect on tumor cell proliferation and by inhibition of endothelial cell migration and angiogenesis mediated by VEGF. In conclusion, compound 8 may normalize the tumor vasculature and microenvironment in tumors probably by inhibiting the binding of VEGF to its receptor.

Anti-angiogenic activity of a small molecule STAT3 inhibitor LLL12

BACKGROUND

Recent data indicate the Signal Transducer and Activator of Transcription 3 (STAT3) pathway is required for VEGF production and angiogenesis in various types of cancers. STAT3 inhibitors have been shown to reduce tumor microvessel density in tumors but a direct anti-angiogenic activity has not been described.

METHODOLOGY/PRINCIPAL FINDINGS

We investigated the direct action of a small molecule inhibitor of STAT3 (LLL12) in human umbilical cord vascular endothelial cells (HUVECs) in vitro, in a Matrigel model for angiogenesis in vivo, and its antitumor activity in a xenograft model of osteosarcoma. LLL12 (100 nM) significantly inhibited VEGF-stimulated STAT3 phosphorylation in HUVECs, reduced their proliferation/migration and inhibited VEGF-induced tube formation. Morphologic analysis of LLL12 treated HUVECs demonstrated marked changes in actin/tubulin distribution and bundling. In scid mice, LLL12 reduced microvessel invasion into VEGF-infused Matrigel plugs by ∼90% at a dose of 5 mg/kg daily. Following a period of tumor progression (2 weeks), LLL12 completely suppressed further growth of established OS-1 osteosarcoma xenografts. Pharmacodynamic studies showed robust phosphorylated STAT3 in control tumors, whereas phospho-STAT3 was not detected in LLL12-treated OS-1 tumors. Treated tumors demonstrated decreased proliferation (Ki67 staining), and decreased microvessel density (CD34 staining), but no significant increase in apoptosis (TUNEL staining), relative to controls. Assay of angiogenic factors, using an antibody array, showed VEGF, MMP-9, Angiopoietin1/2, Tissue Factor and FGF-1 expression were dramatically reduced in LLL12-treated tumors compared to control tumors.

CONCLUSIONS

These findings provide the first evidence that LLL12 effectively inhibits tumor angiogenesis both in vitro and in vivo.

Abstract 5291: A novel gain of function of deltaNp63 in tumor angiogenesis

Background: The p53 families of transcription factors (p53, p63, and p73) are known to be involved in cell stress response, development and tumor suppression. It has been shown that multiple splicing sites and alternative promoter regions lead to each of these proteins having multiple isoforms. The TA isoforms, which contain the transactivation domain, have been shown to induce apoptosis and inhibit cell-cycle progression, suppressing tumorigenesis, while the deltaN isoforms enhance proliferation and inhibit apoptosis, promoting tumorigenesis. Previous studies have shown that the deltaN isoforms are overexpressed in various types of tumors and somehow modulate the expression of proangiogenic and antiangiogenic factors in a different way thus determining the overall angiogenic activity of tumors. Methods: Since expression of deltaNp63 isoform in primary tumors has been shown to correlate with poor prognosis, we attempted to analyze their relationships with tumor angiogenesis. One quick assessment of angiogenesis is the measurement of the ability of endothelial cells to form three-dimensional structures (tube formation) that mimics angiogenesis in vitro. In the presence of angiogenic mediators, endothelial cells form tubes on collagen or fibrin clot coated dishes. To test whether overexpression of oncogenic deltaNp63 in HEK-293T can stimulate tube formation in endothelial cells (like HUVEC), we performed the endothelial tuber formation assay. In addition, we tested in human primary human cells whether there is any a strong correlation between overexpression of oncogenic deltaNp63 isoform and VEGF secretion. Moreover, we performed gene affymetrix as well protein micro array analysis in primary cells compared to cells overexpressed deltaNp63 isoform. In addition, we used siRNA technics to verify any potential role of deltaNp63 isoform in tumor angiogenesis Results: We found that overexpression of oncogenic isoform of p53 family member deltaNp63 in HEK-293T cells resulted in stimulation of tubular structures in HUVEC cells, which can be observed and counted under the microscope. As 293T cells lack functional p53, these results strongly suggest a gain of function for deltaNp63 isoform. In addition, in contrast to pcDNA-electroporated NHFB, used as a control for detection of endogenous VEGF, deltaNp63 overexpressed NHFB show 4 to 5-fold increased VEGF production. Interestingly, our gene expression array showed that ADAMTS8 were induced around 20-Fold in the presence of oncogenic ΔNp63. Conclusions: We found that deltaNp63beta increased VEGF and ADAMTS8 production by p53 independent manner. Our further studies showed that elevated deltaNp63 induced stabilization of HIF-1alpha protein resulting in VEGF secretion in p53 deficient cells. Furthermore, we showed, in the presence of deltaNp63beta isoform, the stabilization of HIF-1alpha and induced ADAMTS8 secretion was dependent on increased STAT3 phosphorylation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5291. doi:1538-7445.AM2012-5291

Abstract 2481: Exploiting BRAF mutation for therapy of childhood low-grade astrocytoma

Activating mutations of BRAF (predominantly V600E) are common in low-grade astrocytomas (∼23%), and xanthoastrocytomas (60%), with or without loss of the CDKN2A locus. Surgically inoperable astrocytoma has a poor prognosis with greater than half of these patients dying from disease. We have developed two models of low-grade astrocytoma (BT-35, BT-40) by direct heterografting patient tumor into immune-deficient mice. Both tumor lines have multiple copies of BRAF, but only BT-40 has an activating mutation (V600E), and is exquisitely sensitive to the MEK inhibitor AZD6244, whereas BT-35 is intrinsically resistant (Kolb et al. Ped Blood Cancer, 2010). Biochemical characterization showed that MEK1/2 were equally inhibited by AZD6244 treatment in both BT-35 and BT-40 xenografts, as demonstrated by the level and duration of inhibition of phospho-ERK1/2. However, inhibition of MEK1/2 had no effect on TORC1 signaling in BT-35 (insensitive) tumors whereas in BT-40 xenografts TORC1 signaling was completely inhibited by AZD6244. The pathway through which mutant BRAF controls TORC1 signaling is currently under evaluation. However, control of TORC1 by mutant BRAF potentially exposes these cells to therapeutic exploitation. We have shown previously that the TOR kinase inhibitor AZD8055 potently suppresses FANCD2, a protein involved in interstrand cross-link (ICL) repair of DNA damage. Similar to the effect of AZD8055, within 4 days treatment of mice with AZD6244, FANCD2 levels are dramatically reduced and were no longer detected in BT-40 xenografts. Preliminary results show that inhibition of TOR signaling by AZD8055 is synergistic with daily radiation in rhabdomyosarcoma xenografts. We hypothesize that because MEK inhibition leads to suppression of TORC1 signaling and FANCD2 in BT-40 astrocytoma xenografts, that combination of AZD6244 with ionizing radiation or drugs that induce ICL will be selectively synergistic in the context of BRAF mutation. Experiments to test the hypothesis are ongoing. Supported by a Peletonia grant from the Ohio State University.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2481. doi:1538-7445.AM2012-2481

Abstract 2317: Direct anti-angiogenic activity of a small molecular STAT3 inhibitor LLL12

Increased vascularization (angiogenesis) is a required adaptation for sustained tumor growth. It is a complex multistage process regulated by a number of signal transduction pathways, although the primary mediator of blood vessel formation is vascular endothelial growth factor (VEGF). Recent data indicate the Signal Transducer and Activator of Transcription 3 (STAT3) is required for VEGF production and angiogenesis in various types of cancers, possibly through regulating hypoxia inducible factor 1 (HIF-1). Other STAT3 inhibitors have been shown to reduce tumor microvessel density in tumors (Lin L et al., Cancer Res. 2010;70:2445-54), but a direct anti-angiogenic activity has not been described. In this study, we investigated the direct action of LLL12 in human umbilical chord vascular endothelial cells (HUVECs). LLL12 (100nM) significantly inhibited VEGF-stimulated STAT3 phosphorylation in HUVEC cells, reduced their proliferation/migration and also inhibited VEGF-induced tube formation. Morphologic analysis of LLL12 treated HUVECS demonstrated significant changes in actin/tubulin distribution and bundling. To test the anti-angiogenic effects of LLL12 in vivo, VEGF-infused Matrigel plugs were implanted into scid mice, and microvessel invasion (CD34 positive cells) determined after 7 days in vehicle treated or LLL12-treated mice. VEGF stimulated microvessel development (∼10-fold) over control plugs (PBS infused). The decreased in microvessel density in LLL12 treated mice was dose dependent, being reduced by ∼90% at a daily dose of 5 mg/kg. To test the antitumor activity of LLL12, mice bearing established OS-1 osteosarcoma xenografts with no treatment, vehicle alone or LLL12 (5 mg/kg daily) for 6 weeks. Following a period of tumor progression, LLL12 completely suppressed further growth. Pharmacodynamic studies at the end of treatment showed robust phosphor-STAT3 in control tumors whereas phosphor-STAT3 was not detected in treated OS-1 tumors. Treated tumors demonstrated decreased proliferation (Ki67 staining) but no significant increase in apoptosis (TUNEL staining), relative to controls. To examine the effect of LLL12 on angiogenic factors a Proteome Profiler antibody array was used to detect the relative levels of expression of 55 angiogenesis related proteins in control and treated OS-1 tumors. Several critical regulators of angiogenesis including VEGF, MMP-9, Angiopoieion1/2, Tissue Factor and FGF-1 expression were significantly reduced in LLL12 treated tumors compared to control OS-1 xenografts. These findings provide the first evidence that LLL12 effectively inhibits tumor angiogenesis both in vitro and in vivo. These data indicate that the inhibition of STAT3 signaling is a potential therapeutic approach for tumor angiogenesis, and tumor control. Supported in part through a Pelotonia grant from OSU.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2317. doi:1538-7445.AM2012-2317

Potent inhibition of angiogenesis by the IGF-1 receptor-targeting antibody SCH717454 is reversed by IGF-2

Previously, we reported that a predominant action of a type-1 insulin-like growth factor receptor (IGF-1R)-targeted antibody was through inhibiting tumor-derived VEGF, and indirectly, angiogenesis. Here, we examined the direct antiangiogenic activity of the IGF-1R-targeted antibody SCH717454 that inhibits ligand-receptor binding and the mechanism by which tumors circumvent its antiangiogenic activity. Inhibition of ligand-stimulated activation of IGF-1R, insulin receptor (IN-R), or downstream signaling [phosphorylation of Akt (Ser473)] was determined by receptor-specific immunoprecipitation and immunoblotting. Inhibition of angiogenesis was determined by proliferation and tube formation using human umbilical vein endothelial cells (HUVEC) in vitro and in Matrigel plugs implanted in mice. SCH717454 blocked IGF-1-stimulated but not IGF-2-stimulated phosphorylation of Akt in sarcoma cells. Immunoprecipitation using anti-IGF-1R and anti-IN-R antibodies revealed that SCH717454 equally blocked IGF-1-stimulated and IGF-2-stimulated IGF-1R phosphorylation, but not IGF-2-stimulated phosphorylation of IN-R. SCH717454 completely blocked VEGF-stimulated proliferation and tube formation of HUVECs, but exogenous IGF-2 and insulin circumvented these inhibitory effects. Coculture of HUVECs with IGF-2-secreting tumor cells completely abrogated SCH717454 inhibition of VEGF-stimulated HUVEC tube formation. In mice, SCH717454 inhibited angiogenesis in VEGF-infused Matrigel plugs, but had no inhibitory activity when plugs contained both VEGF + IGF-2. These results reveal for the first time, a role for IGF-1R signaling in VEGF-mediated angiogenesis in vitro and indicate direct antiangiogenic activity of SCH717454. Both in vitro and in vivo IGF-2 circumvented these effects through IN-R signaling. Many childhood cancers secrete IGF-2, suggesting that tumor-derived IGF-2 in the microenvironment maintains angiogenesis in the presence of IGF-1R-targeted antibodies allowing tumor progression.

E-nephrology

Diagnosis of renal diseases is often delayed owing to the scarcity of trained physicians, lack of facilities, and shortage of funds limits effective management, particularly when it comes to the red zone of renal replacement therapy. The Internetis expected to open up a myriad resource of knowledge and applications for academicians, researchers and clinicians alike in all health care professions across the globe. Also, the Internet has grown rapidly over the years and will inevitably expand even more. Evolving technologies offer modern applications for information management, communications with multimedia and virtual reality. Now, these innovative technologies have opened up newer possibilities for nephrologists. As Internet is serving as a backbone for these modern technologies, it is an utmost necessity to use and refine Internet applications for future nephrologists. Increasingly easy access to Internet has dramatically reduced barriers in sharing of information among basic and clinical nephrologists. Considering the growing scope for nephrologists in the use of Internet, it is necessary to understand Internet as a source of information and backbone of modern application. This review illustrates expanding roles of the Internet for the nephrologists and provides ready to use compilation of useful academic, research, clinical resources and is expected to introduce, stimulate and guide nephrologists into the realm of the world wide web. It also investigates how Internet is supporting in growth and development of the field of nephrology and present and future scopes of Internet as a tool for professionals involved in this area as well as information about biological sciences, and it also gives information about societies in various continents working in field of nephrology and the links useful for clinicians and research scientists.

Abstract 3277: Insulin-like growth factor-2 (IGF-2) circumvents the antiangiogenic activity of SCH717454, a human antibody that blocks ligand binding to the Type 1 insulin-like growth factor receptor (IGF-1R)

Background. Deregulated insulin-like growth factor signaling through IGF-1R is common to many human cancers, including childhood solid tumors, and has become an important target for therapeutics development. We reported that there was a rapid decrease in tumor-associated VEGF in childhood sarcoma xenografts responding to an IGF-1R-targeted antibody (Kurmasheva RT Cancer Res, 2010). Subsequently the IGF-1R targeted antibody SCH717454 (SCH) was shown to reduce blood vessel formation in tumor xenografts (Wang Y Mol Cancer Ther. 2010). However, relatively few xenograft tumors respond to treatment (Kolb EA Ped Blood &Cancer, 2009). Here we examine a possible contributing factor to resistance to IGF-1R blockade.

Methods. IGF-1R activity was measured by phosphorylation of IGF-1R, insulin receptor (IN-R), and Akt subsequent to addition of ligand (IGF-1, IGF-2). Effects of SCH on angiogenesis in vitro were determined by HUVEC proliferation and tube formation assays. Angiogenesis in vivo was determined using Matrigel plugs infused with PBS (control), VEGF or VEGF+IGF-2 and assay of hemoglobin and CD34 immunostaining.

Results. SCH rapidly blocked IGF-1 but not IGF-2 stimulated phosphorylation of Akt in all sarcoma cell lines. Immunoprecipitation using anti-IGF-1R and anti-IN-R antibodies revealed that in the presence of SCH, IGF-2 partially signaled through IGF-1R but significantly induced phosphorylation of IN-R. SCH completely blocked VEGF-stimulated proliferation and tube formation of HUVECs indicating that IGF-1R signaling is essential to these processes. Exogenous IGF-2, but not IGF-1, circumvented SCH inhibition of VEGF- stimulated proliferation and tube formation. In mice SCH (20 mg/kg) dramatically inhibited angiogenesis in VEGF-infused Matrigel plugs, demonstrating anti-angiogenic activity. However, mice lack circulating IGF-2, and many childhood sarcomas secrete IGF-2. To test whether IGF-2 could circumvent the antiangiogenic activity of SCH in vivo, Matrigel plugs infused with VEGF or VEGF+IGF-2 were implanted. SCH suppressed angiogenesis into VEGF-infused Matrigel plugs, but had no inhibitory activity when plugs contained both VEGF+IGF-2. Similarly, in vitro co-culture of HUVECs with IGF-2-secreting tumor cells (Rh30) in transwell plates completely abrogated SCH inhibition of VEGF-stimulated HUVEC proliferation/tube formation.

Conclusions. These results support the anti-angiogenic activity of SCH. Both in vitro and in vivo IGF-2 circumvented the effects of SCH and other IGF-1R-targeted antibodies examined in clinical development. Many childhood cancers secrete IGF-2, suggesting that tumor-derived IGF-2 in the microenvironment maintains angiogenesis in the presence of antibodies such as SCH. (Supported by NCI awards CA77776, CA23099 and from Schering-Plough).

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3277. doi:10.1158/1538-7445.AM2011-3277

Targeting angiogenesis in childhood sarcomas

Angiogenesis and vasculogenesis constitute two processes in the formation of new blood vessels and are essential for progression of solid tumors. Consequently, targeting angiogenesis, and to a lesser extent vasculogenesis, has become a major focus in cancer drug development. Angiogenesis inhibitors are now being tested in pediatric populations whereas inhibitors of vasculogenesis are in an earlier stage of development. Despite the initial enthusiasm for targeting angiogenesis for treatment of cancer, clinical trials have shown only incremental increases in survival, and agents have been largely cytostatic rather than inducing tumor regressions. Consequently, the role of such therapeutic approaches in the context of curative intent for childhood sarcomas is less clear. Here we review the literature on blood vessel formation in sarcomas with a focus on pediatric sarcomas and developments in targeting angiogenesis for treatment of these rare cancers.

Association of glutathione S-transferase (GSTM1, T1 and P1) gene polymorphisms with type 2 diabetes mellitus in north Indian population

BACKGROUND

Diabetes mellitus is associated with an increased production of reactive oxygen species (ROS) and a reduction in antioxidant defense. The oxidative stress becomes evident as a result of accumulation of ROS in conditions of inflammation and Type 2 diabetes mellitus (T2DM). The genes involved in redox balance, which determines the susceptibility to T2DM remain unclear. In humans, the glutathione S-transferase (GST) family comprises several classes of GST isozymes, the polymorphic variants of GSTM1, T1 and P1 genes result in decreased or loss of enzyme activity.

AIMS

The present study evaluated the effect of genetic polymorphisms of the GST gene family on the risk of developing T2DM in the North Indian population.

SETTINGS AND DESIGN

GSTM1, T1 and P1 polymorphisms were genotyped in 100 T2DM patients and 200 healthy controls from North India to analyze their association with T2DM susceptibility.

MATERIALS AND METHODS

Analysis of GSTM1 and GSTT1 gene polymorphisms was performed by multiplex polymerase chain reaction (PCR) and GSTP1 by PCR-Restriction Fragment Length Polymorphism (RFLP).

STATISTICAL ANALYSIS

Fisher's exact test and chi2 statistics using SPSS software (Version-15.0).

RESULTS

We observed significant association of GSTM1 null (P=0.004, OR= 2.042, 95%CI= 1.254-3.325) and GSTP1 (I/V) (P=0.001, OR= 0.397, 95%CI=0.225-0.701) with T2DM and no significant association with GSTT1 (P=0.493). The combined analysis of the three genotypes GSTM1 null, T1 present and P1 (I/I) demonstrated an increase in T2DM risk (P= 0.005, OR= 2.431 95% CI=1.315-4.496).

CONCLUSIONS

This is the first study showing the association of a combined effect of GSTM1, T1 and P1 genotypes in a representative cohort of Indian patients with T2DM. Since significant association was seen in GSTM1 null and GSTP1 (I/V) and multiple association in GSTM1 null, T1 present and P1 (I/I), these polymorphisms can be screened in the population to determine the diabetic risk.

Polymorphisms in the vitamin D receptor and the androgen receptor gene associated with the risk of urolithiasis

Transcriptional activity of the vitamin D receptor (VDR) gene is regulated by androgen receptor (AR) gene and both are associated with renal stone formation. We examined gene polymorphisms of VDR (PCR-RFLP) and AR (GeneScan analysis) in 125 stone formers and 150 controls from north India. Genotype Ff of Fok-I and Tt of Taq-I demonstrated significantly higher risk (P<0.001, OR=3.559 and P=0.019, 1.830 respectively). Variant f allele exhibited 1.7-folds higher risk. Ff of Fok-I and Aa of Apa-I gene polymorphism showed higher risk in males only. Mean CAG repeat was significantly higher in hypercalciuric patients as compared to normocalciuric (mean=21.62 ± 3.384 vs. 20.11 ± 3.182; P=0.034). Combined effects 1.8-folds higher risk in patients with Tt genotype of Taq-I and short CAG repeat. Thus, association of FokI and TaqI VDR gene polymorphisms suggest VDR as an important genetic marker for urolithiasis. Further, patients with combination of Tt of Taq-I and short CAG repeat were at higher risk for stone formation.

Reinventing the ACE inhibitors: some old and new implications of ACE inhibition

Since their inception, angiotensin-converting enzyme (ACE) inhibitors have been used as first-line therapy for the treatment of cardiovascular and renal diseases. They restore the balance between the vasoconstrictive salt-retentive and hypertrophy-causing peptide angiotensin II (Ang II) and bradykinin, a vasodilatory and natriuretic peptide. As ACE is a promiscuous enzyme, ACE inhibitors alter the metabolism of a number of other vasoactive substances. ACE inhibitors decrease systemic vascular resistance without increasing heart rate and promote natriuresis. They have been proven effective in the treatment of hypertension, and reduce mortality in congestive heart failure and left ventricular dysfunction after myocardial infarction. They inhibit ischemic events and stabilize plaques. Furthermore, they delay the progression of diabetic nephropathy and neuropathy and act as antioxidants. Ongoing studies have elucidated protective roles for them in both memory-related disorders and cancer. Lastly, N- and C-domain selective ACE inhibitors have led to new uses for ACE inhibitors.

Endocrinological cancers and the internet

Endocrine cancers are some of the commonest forms of cancer getting mention as early as in old papyruses of Egypt. Our current knowledge about this cluster of cancer has grown immensely with improved survival rates. In the era of specialization and super specialization, we started peeking into these conditions more elaborately and beyond microscopically. The growing awareness demanded categorization of information into disease basics like molecular pathology of initiation and progression; advanced diagnostics; new therapeutic options; patient awareness and involvement in clinical trials. Recent advances in genomics and hereditary counseling have delineated pre-disease forecasting possibilities. With advanced diagnostics and therapeutic modalities, we saw an increase in cancer survivors demanding extra care and moral support. Throughout these developments, we went through a boost in global information communications, the main thrust being the Internet. Networking of computers globally generated a platform that created a ripple of knowledge far and wide. The purpose of this review is to investigate how the Internet is supporting the growth and development of the field of endocrine cancer, and present and future scope of the Internet as a tool for professionals involved in this area. The information furnished here were collected from cited references as well as all websites mentioned in the tables.

E-endocrinology: an update

Internet, from a long time, has opened up a myriad resource of knowledge and applications for academicians, researchers and clinicians alike in all health care professions across the globe. Basic endocrinologists are exploring through bench-top protocols to understand endocrine system and to design therapeutic interventions. Clinicians are required to continuously look for new developments relating to investigation, diagnosis and therapeutic options in their everyday practice for better quality of life of patients. All these require managing a large body of information. Now, these innovative technologies have opened up newer avenues for endocrinologists. As internet is serving the backbone for modern technologies, it is of utmost necessity to use and refine internet applications for future endocrinologists. Increasingly, easy access to internet has dramatically reduced barriers in sharing information among basic and clinical endocrinologists. Considering the growing scope for endocrinologists in the use of internet, it is necessary to understand internet as a source of information and backbone of modern applications. This review illustrates the expanding roles of the internet for endocrinologists and provides a ready-to-use compilation of useful academic, research, clinical resources, and is expected to introduce, stimulate and guide endocrinologists into the realm of WWW.

Cell growth inhibitory action of an unusual labdane diterpene, 13-epi-sclareol in breast and uterine cancersin vitro

In the course of our studies on the isolation of bioactive compounds from the roots of Coleus forskohlii, a traditional herb in India, rare 13-epi-sclareol has been isolated, and its structure determined by extensive 2D NMR. This is the first report of isolation from this plant. The isolated compound showed antiproliferative activity in breast and uterine cancers in vitro. The antiproliferative activity of 13-epi-sclareol is comparable to Tamoxifen in terms of IC50 and also showed concentration dependent increased apoptotic changes in the breast cancer cell line, MCF-7.

Analysis of polymorphisms of tumor necrosis factor-alpha and polymorphic xenobiotic metabolizing enzymes in inflammatory bowel disease: study from northern India

BACKGROUND

Tumor necrosis factor (TNF)-alpha is a proinflammatory cytokine associated with inflammatory diseases, while GSTM1 and T1 enzymes catalyze detoxification of products of oxidative stress and hence reduce inflammation. Thus, both may play important roles in the pathogenesis of inflammatory bowel disease (IBD). The present study aimed to evaluate the effect of polymorphism of the TNF-alpha promoter at the -308 site, GSTM1 and GSTT1 in patients with IBD and healthy controls from northern India.

METHOD

Genotyping was performed in 114 patients with IBD (22 Crohn's disease [CD] and 92 ulcerative colitis [UC]) in TNF-alpha and 105 (20 CD and 85 UC) in GSTM1 and T1 and 164 healthy controls using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and multiplex PCR methods.

RESULTS

Patients with IBD were comparable to healthy controls in relation to age and gender. Genotypic and allelic frequencies of TNF-alpha were comparable among patients with IBD and healthy controls. GSTM1 null genotype was more frequent in UC than in healthy controls (52/85 vs 49/164; P < 0.001) and GSTT1 null genotype was more frequent both in UC and CD as compared to healthy controls (77/85 and 18/20 vs 26/164, respectively; P < 0.001 for both). Frequency of combined null genotype in GSTM1 and T1 was more frequently associated with IBD than healthy controls (4/20 vs 8/164; P = 0.029, OR = 4.875 and 28/85 vs 8/164; P < 0.001, OR = 9.579, respectively).

CONCLUSIONS

'Null' genotypes of GSTM1 and T1 are associated with IBD and the combination of the two GST genotypes further increases the risk, possibly due to gene-gene interaction. TNF-alpha is unlikely to be an important determinant of susceptibility to IBD in the Indian population.

Association of vitamin-D receptor (Fok-I) gene polymorphism with bladder cancer in an Indian population

OBJECTIVE

To explore the association of vitamin-D receptor (VDR) genotypes and haplotypes (variants at the Fok-I, and Taq-I sites) with the risk of bladder cancer, as vitamin D is antiproliferative and reported to induce apoptosis in human bladder tumour cells in vitro.

PATIENTS, SUBJECTS AND METHODS

A case-control study using polymerase chain reaction-restriction fragment length polymorphism was conducted in 130 patients with bladder cancer and 346 normal healthy individuals in a north Indian population. Patients were also categorized according to grade and stage of tumour.

RESULTS

There was a significant difference in genotype and allelic distribution of VDR (Fok-I) polymorphism in the patients (P = 0.033 and = 0.017, respectively). The FF genotype was associated with twice the risk for bladder cancer (odds ratio 2.042, 95% confidence interval, CI, 0.803-5.193). There was no significant difference in genotypic distribution or allelic frequencies of the VDR (Taq-I) polymorphism (P = 0.477 and 0.230) when compared with the controls. The stage and grade of the bladder tumours had no association with VDR (Fok-I and Taq-I) genotypes. There was a significant difference in the frequency distribution of the haplotypes FT and fT (P < 0.001); these haplotypes had a protective effect in the control group (odds ratio 0.167, 95% CI 0.096-0.291, and 0.079, 0.038-0.164).

CONCLUSION

These data suggest that VDR (Fok-I) polymorphism is associated with the risk of bladder cancer. Further, the results for the haplotype FT and fT indicate that patients with this haplotype have a lower risk of developing bladder cancer than those with other haplotypes.

Genotype and haplotype determination of IL1B (g. −511C>T and g. +3954C>T) and (IL1RN) in pediatric nephrolithiasis

BACKGROUND

Nephrolithiasis is a multifactorial and polygenic disorder characterized by presence of stones in urinary tract. Interleukin1 (IL1) plays role in process of bone loss/hypercalciuria and is involved in formation of kidney stones. We investigated the association between IL1B promoter region and exon-5 (g.-511C>T and g. +3954C>T) polymorphism and variable number of tandem repeats in IL1 receptor antagonist, IL1RN (IVS2) with risk of stone formation in childhood nephrolithiasis in north Indian population.

METHODS

Control group of 60 healthy pediatric individuals (age range =4-16 y) and 50 pediatric nephrolithiasis patients (age range =2-14 y) were studied. Polymorphism was detected by PCR based restriction analysis. Haplotypes for IL1B and IL1RN were constructed using Arlequin v2.0 software.

RESULTS

Distribution of IL1RN gene polymorphism demonstrated significant difference (p=0.023). Pediatric patients had significantly higher frequency of allele I in IL1RN (16% vs. 1.7%). The distribution of IL1B (g. -511C>T and g. +3954C>T) genotypes in patients and controls were similar (p=0.263 and 0.694 respectively). There was a significant difference in haplotype frequencies between pediatric patients and control group (p<0.05). Haplotype T-E1-I showed>7-folds risk for nephrolithiasis (p=0.033; OR=7.07, 95% CI=1.16-42.84).

CONCLUSIONS

Significant association was observed for allele I(*) of IL1RN however, no association was observed for IL1B. Haplotype T-E1-I was significantly associated with higher risk of pediatric nephrolithiasis. These findings suggest that the IL1RN and haplotyping may be an influential marker for susceptibility to pediatric nephrolithiasis.

Interleukin-1beta and receptor antagonist (IL-1Ra) gene polymorphisms and the prediction of the risk of end-stage renal disease

Cytokines play an important role in the pathogenesis of kidney disease and its progression to end-stage renal disease (ESRD). Inflammation is regulated by the genes of the interleukin 1 (IL-1) gene cluster. Therefore, it was hypothesized that a polymorphism in this gene cluster may be associated with the risk of ESRD. Polymorphisms in the IL-1 gene cluster were examined in a cohort of 222 ESRD patients and 206 controls of similar ethnicity. These individuals were genotyped for IL-1 beta (promoter -511 and exon-5 +3953) genes and a variable number of tandem repeats (VNTR) in the IL-1 receptor antagonist gene (IL-1Ra). There was significant difference in genotype frequencies between ESRD patients and control group for IL-1beta (promoter region and exon-5) and IL-1Ra gene polymorphism (p < 0.001, 0.006 and < 0.001, respectively). A significant difference was observed in IL-1Ra for 1/1 (410/410) and 1/2 (410/240) genotypes, and the risk for ESRD was higher in those carrying the 1/1 genotype (p = 0.014, OR = 1.692, and p < 0.001, OR = 0.163). Also identified was a novel, rare allele of a single copy of 86 bp in ESRD patients as compared with the controls. The haplotype 'T-E2-1' frequency distribution between patients and controls revealed greater than threefold risk (p = 0.001, OR = 3.572, 95% CI = 1.589-8.032). Genetic linkage between the IL-1beta promoter region and exon-5 and between the IL-1beta promoter and IL-1Ra of IL-1 gene demonstrated a strong association among the variants in controls (D' = 0.42, p < 0.001, and D' = 0.39, p=0.001). Thus, the three polymorphisms within the IL-1 cluster are associated with ESRD. This finding is perhaps one of the strongest associations between genotype and ESRD reported, and it suggests that the IL-1 gene cluster affects the risk of development of ESRD.

Association of Urokinase Gene 3′-UTR Polymorphism with Calcium Oxalate Nephrolithiasis

PURPOSE

Urokinase might play a role in the formation of kidney stones. The aim of this study was to investigate the role of the urokinase gene in calcium oxalate nephrolithiasis.

SUBJECTS AND METHODS

A control group of 150 healthy individuals having no history of stone formation (mean age 40 +/- 11.5 years) and a group of 130 patients (mean age 40.5 +/- 10.5 years) with recurrent calcium oxalate stones were examined. The C/T polymorphism of the urokinase gene was detected using polymerase chain reaction (PCR)-based restriction analysis.

RESULTS

A marginally significant difference (P = 0.035) was found in the distribution of the urokinase gene 3' untranslated region (UTR) C/T polymorphism between patients with stones and controls. The odds ratio for the risk of the T allele in stone patients was 1.006 (95% CI 0.63-1.62).

CONCLUSION

The T allele of 3' UTR of the urokinase gene may not be associated with a higher risk of stone formation.

Ethnicity greatly influences the interleukin-1 gene cluster(IL-1b promoter, exon-5 and IL-1Ra) polymorphisms: a pilot study of a north Indian population

There is considerable evidence that polymorphisms in the regulatory regions of cytokine genes are highly influenced by ethnicity. Polymorphisms in interleukin 1-beta (IL-1beta) and IL-1 receptor antagonist (IL-1Ra) genes, respectively encoding a potent inflammatory agent and an antagonist, which combines with IL-1 receptors competitively, have been associated with a number of diseases like systemic lupus erythematosus, rheumatoid arthritis, sepsis, kidney diseases, and cancer. In this study, we therefore evaluated the distribution of interleukin-1 gene cluster (IL-1beta promoter region, exon-5 and IL-1Ra) gene polymorphisms in 206 healthy north Indian subjects, using PCR-based restriction analysis. We also constructed various haplotypes and estimated the linkage disequilibrium (LD). We found that genotype and allelic frequencies for these cytokines were conspicuously different when compared among different ethnic populations. The haplotype 'T-E1-1' predominated (41.7%) while the least common was 'C-E2-2' (2%) in our population. Genetic linkage between three loci of IL-1 gene showed strong association among the variants in controls (D'=0.42, p<0.001). Our results suggest that the frequency and distribution of the polymorphisms in India are substantially different from other populations and ethnic groups. Thus they signify an impact of ethnicity and provide a basis for future epidemiological and clinical studies.

IL-1 receptor antagonist (IL-1Ra) gene polymorphism in patients with inflammatory bowel disease in India

OBJECTIVE

An association between polymorphism in the gene coding for the anti-inflammatory cytokine interleukin-1-receptor antagonist (IL-1Ra) and ulcerative colitis (UC) has been reported. To date, there is no report from India confirming this association. In the present study the aim was to assess the allele frequencies and carriage rates of different alleles of 86 bp (base pair) variable number tandem repeat (VNTR) in intron 2 of the IL-1Ra gene in patients with inflammatory bowel disease (IBD) and healthy controls from northern India.

MATERIAL AND METHODS

Eighty-two patients with UC, 21 with Crohn's disease (CD) and 141 ethnically matched controls were enrolled in this study. Genotyping was done using a polymerase chain reaction (PCR) amplification of the intron-2 fragment harboring a VNTR nucleotide sequence. The PCR products were separated on 2% agarose gel. Statistical analysis was performed using the chi-squared (chi(2)) test.

RESULTS

The frequencies of allele 2 in UC, CD and healthy controls were 26%, 50% and 24%, respectively. The frequency of allele 2 in CD was higher than that in UC (p = 0.002; OR = 2.9) and healthy controls (p = 0.001; OR = 3.1; 95% CI = 1.5-6.3). Alleles 3 and 4 were absent in patients with CD, while allele 5 was absent in all three groups.

CONCLUSIONS

The present study demonstrated an association between allele 2 and patients with CD but not with UC. Interestingly, the allele frequency and carriage rates of allele 2 were significantly higher in patients with CD than in patients with UC and in healthy subjects. Ethnic differences, genetic heterogeneity and sample size could be the reasons for such differences in comparison with studies from the West.

Effect of antibiotics on Oxalobacter formigenes colonization of human gastrointestinal tract

BACKGROUND AND PURPOSE

Oxalobacter formigenes is a bacterium residing in the human gastrointestinal tract that degrades oxalate and reduces its availability for absorption. This bacterium is assumed to be antibiotic sensitive, and repeated antibiotic therapies could eradicate it. The aim of the present study was to determine the differences in the colonization by O. formigenes of individuals who had been on antibiotics for at least 5 days at the time of sample collection and individuals who had not taken antibiotics for at least 3 months.

PATIENTS AND METHODS

Stool samples were collected from 80 individuals without stone disease (35 with and 45 without antibiotic consumption) and 100 patients with stone disease (20 with and 80 without antibiotic consumption). Oxalobacter formigenes was detected by a polymerase chain reaction-based method, and the presence/absence of O. formigenes was correlated with urinary oxalate concentrations.

RESULTS

Lower percentages of individuals without stone disease and with stone disease who were consuming antibiotics had O. formigenes colonization than individuals without antibiotic consumption. Urinary oxalate concentrations were higher in the individuals without O. formigenes than in colonized individuals.

CONCLUSION

Our observations confirm a direct association between antibiotic consumption and absence of O. formigenes. Absence of intestinal O. formigenes could represent a pathogenic factor in calcium oxalate urolithiasis when antibiotics are prescribed generously.

Vitamin-D receptor (VDR) gene (Fok-I, Taq-I and Apa-I) polymorphisms in healthy individuals from north Indian population

The vitamin-D endocrine system is involved in a wide variety of biological processes including bone metabolism, modulation of immune responses, and regulation of cell proliferation and differentiation. Variation in this endocrine system have, thus, been linked to several common diseases, including osteoarthritis (OA), diabetes, cancer, cardiovascular ailments, urolithiasis and tuberculosis. Activity of Vit-D is mediated by the vitamin D receptor (VDR), a ligand dependent receptor. VDR gene polymorphisms thus represent strong positional candidates for different diseases like prostate cancer, urolithiasis, inflammatory bowl disease and osteoporosis. Genetic studies provide excellent opportunities to link molecular insights with epidemiological data and can reveal modest and subtle but true biological effects. The abundance of polymorphisms in the human genome as well as high frequencies in human populations have made them targets to explain variation in risk of common diseases. The present study was carried out to determine the distribution of VDR gene (Fok-I, Taq-I and Apa-I) polymorphisms using a PCR-based restriction analysis in unrelated normal healthy individuals from a north Indian population. We obtained allelic frequencies of (68.5% vs 31.5%), (66% vs 34%) and (58% vs 42%) for (F vs f), (T vs t) and (A vs a) alleles, with 44%, 49% and 7%, respectively, for genotypes FF, Ff and ff , 49%, 40% and 11% for TT, Tt and tt and 36%, 44% and 20% for AA, Aa and aa. Our results suggest that the frequency and distribution of the polymorphisms in India are substantially different from in other populations and ethnic groups. Thus the data signify an impact of ethnicity and provide a basis for future epidemiological and clinical studies.