The anti-proliferative effects of a frankincense extract in a window of opportunity phase ia clinical trial for patients with breast cancer.

PURPOSE: Boswellic acids, active components of frankincense, suppress tumor proliferation in vitro with a strong clinical trial safety profile in patients with inflammatory diseases. We performed a Phase Ia window of opportunity trial of Boswellia serrata (B. serrata) in patients with breast cancer to evaluate its biologic activity and safety. METHODS: Patients with invasive breast cancer were treated pre-operatively with B. Serrata (2400 mg/day PO) until the night before surgery for a median of 11 days (SD 6 days; range: 5-23 days). Paraffin-embedded sections from pretreatment diagnostic core biopsies and post-treatment surgical excisions were evaluated using a tunnel assay and immunohistochemistry staining with Ki-67 antibodies. A non-intervention retrospective control arm consisting of core and surgical tissue specimens from untreated patients was used to compare patients treated with B. Serrata. The change in proliferation and apoptosis between diagnostic core specimens and surgical specimens was compared between the control and treatment groups using a two-tailed paired t-test. RESULTS: Twenty-two patients were enrolled, of which 20 received treatment, and 18 had sufficient tissue for IHC. There was an increase in percent change in proliferation from core biopsy to surgical excision in the control group (n = 18) of 54.6 ± 21.4%. In the B. serrata-treated group there was a reduction in proliferation between core biopsy and excision (n = 18) of 13.8 ± 11.7%. This difference was statistically significant between the control and B. serrata-treated groups (p = 0.008). There was no difference in change in apoptosis. There were no serious adverse events related to the drug. CONCLUSION: Boswellia serrata inhibited breast cancer proliferation and was well-tolerated in a Phase Ia window of opportunity trial.

Secreted frizzled related-protein 2 is prognostic for human pancreatic cancer patient survival and is associated with fibrosis.

Pancreatic adenocarcinoma (PDAC) is one of the deadliest cancers, with five-year survival rates of 9%. We hypothesized that secreted frizzled-related protein 2 (SFRP2) may influence stromal growth in pancreatic cancer, since it increases fibrosis and collagen production in non-neoplastic pathologies. We assessed SFRP2 value as a biomarker and assessed its function in PDAC. SFRP2 gene expression in patients with PDAC was analyzed using TCGA data. Disease free survival (DFS) was analyzed using Kaplan Meier test. The effect of KRAS inhibition on SFRP2 expression in PDAC cells was assessed. The associations of stromal content with SFPR2 mRNA and protein with fibrosis were analyzed. The role of SFRP2 in mesenchymal transformation was assessed by western blot in fibroblasts. Of all cancers in TCGA, SFRP2 levels were highest in PDAC, and higher in PDAC than normal tissues (n= 234, p= 0.0003). High SFRP2 levels correlated with decreased DFS (p= 0.0097). KRAS inhibition reduced SFRP2 levels. Spearman correlation was 0.81 between stromal RNA and SFRP2 in human PDAC, and 0.75 between fibrosis and SFRP2 levels in PDAC tumors. SFRP2-treated fibroblasts displayed mesenchymal characteristics. SFRP2 is prognostic for PDAC survival, regulated by KRAS, and associated with PDAC fibrosis.

Overcoming PD-1 Inhibitor Resistance with a Monoclonal Antibody to Secreted Frizzled-Related Protein 2 in Metastatic Osteosarcoma.

Secreted frizzled-related protein 2 (SFRP2) promotes the migration/invasion of metastatic osteosarcoma (OS) cells and tube formation by endothelial cells. However, its function on T-cells is unknown. We hypothesized that blocking SFRP2 with a humanized monoclonal antibody (hSFRP2 mAb) can restore immunity by reducing CD38 and PD-1 levels, ultimately overcoming resistance to PD-1 inhibitors. Treating two metastatic murine OS cell lines in vivo, RF420 and RF577, with hSFRP2 mAb alone led to a significant reduction in the number of lung metastases, compared to IgG1 control treatment. While PD-1 mAb alone had minimal effect, hSFRP2 mAb combination with PD-1 mAb had an additive antimetastatic effect. This effect was accompanied by lower SFRP2 levels in serum, lower CD38 levels in tumor-infiltrating lymphocytes and T-cells, and lower PD-1 levels in T-cells. In vitro data confirmed that SFRP2 promotes NFATc3, CD38 and PD-1 expression in T-cells, while hSFRP2 mAb treatment counteracts these effects and increases NAD+ levels. hSFRP2 mAb treatment further rescued the suppression of T-cell proliferation by tumor cells in a co-culture model. Finally, hSFRP2 mAb induced apoptosis in RF420 and RF577 OS cells but not in T-cells. Thus, hSFRP2 mAb therapy could potentially overcome PD-1 inhibitor resistance in metastatic osteosarcoma.

Development of a Novel Humanized Monoclonal Antibody to Secreted Frizzled-Related Protein-2 That Inhibits Triple-Negative Breast Cancer and Angiosarcoma Growth In Vivo.

BACKGROUND: We previously reported that secreted frizzled-related protein-2 (SFRP2) is expressed in a variety of tumors, including sarcoma and breast carcinoma, and stimulates angiogenesis and inhibits tumor apoptosis. Therefore, we hypothesized that a humanized SFRP2 monoclonal antibody (hSFRP2 mAb) would inhibit tumor growth. METHODS: The lead hSFRP2 antibody was tested against a cohort of 22 healthy donors using a time course T-cell assay to determine the relative risk of immunogenicity. To determine hSFRP2 mAb efficacy, nude mice were subcutaneously injected with SVR angiosarcoma cells and treated with hSFRP2 mAb 4 mg/kg intravenously every 3 days for 3 weeks. We then injected Hs578T triple-negative breast cells into the mammary fat pad of nude mice and treated for 40 days. Control mice received an immunoglobulin (Ig) G1 control. The SVR and Hs578T tumors were then stained using a TUNEL assay to detect apoptosis. RESULTS: Immunogenicity testing of hSFRP2 mAb did not induce proliferative responses using a simulation index (SI) ≥ 2.0 (p < 0.05) threshold in any of the healthy donors. SVR angiosarcoma tumor growth was inhibited in vivo, evidenced by significant tumor volume reduction in the hSFRP2 mAb-treated group, compared with controls (n = 10, p < 0.001). Likewise, Hs578T triple-negative breast tumors were smaller in the hSFRP2 mAb-treated group compared with controls (n = 10, p < 0.001). The hSFRP2 mAb treatment correlated with an increase in tumor cell apoptosis (n = 11, p < 0.05). Importantly, hSFRP2 mAb treatment was not associated with any weight loss or lethargy. CONCLUSION: We present a novel hSFRP2 mAb with therapeutic potential in breast cancer and sarcoma that has no effect on immunogenicity.

Genetic Variants of VEGFA and FLT4 Are Determinants of Survival in Renal Cell Carcinoma Patients Treated with Sorafenib.

Molecular markers of sorafenib efficacy in patients with metastatic renal cell carcinoma (mRCC) are not available. The purpose of this study was to discover genetic markers of survival in patients with mRCC treated with sorafenib. Germline variants from 56 genes were genotyped in 295 patients with mRCC. Variant-overall survival (OS) associations were tested in multivariate regression models. Mechanistic studies were conducted to validate clinical associations. VEGFA rs1885657, ITGAV rs3816375, and WWOX rs8047917 (sorafenib arm), and FLT4 rs307826 and VEGFA rs3024987 (sorafenib and placebo arms combined) were associated with shorter OS. FLT4 rs307826 increased VEGFR-3 phosphorylation, membrane trafficking, and receptor activation. VEGFA rs1885657 and rs58159269 increased transcriptional activity of the constructs containing these variants in endothelial and RCC cell lines, and VEGFA rs58159269 increased endothelial cell proliferation and tube formation. FLT4 rs307826 and VEGFA rs58159269 led to reduced sorafenib cytotoxicity. Genetic variation in VEGFA and FLT4 could affect survival in sorafenib-treated patients with mRCC. These markers should be examined in additional malignancies treated with sorafenib and in other angiogenesis inhibitors used in mRCC. SIGNIFICANCE: Clinical and mechanistic data identify germline genetic variants in VEGFA and FLT4 as markers of survival in patients with metastatic renal cell carcinoma.

TRAF3-interacting protein 3, a new oncotarget, promotes tumor growth in melanoma.

TRAF3-interacting protein 3 (TRAF3IP3) is expressed in the immune system and participates in cell maturation, tissue development, and immune response. In a previous study, we reported that TRAF3IP3 levels were substantially increased in the vasculature of breast cancer tissues, suggesting a proangiogenic role. In this study, we investigated TRAF3IP3 tumorigenic function. TRAF3IP3 protein was present in several cancer cell lines, with highest levels in melanoma. In addition, tumor microarray analysis on 23 primary melanoma and nine positive lymph nodes revealed that 70% of human primary melanoma and 66% of lymph node metastases were positive for TRAF3IP3. Importantly, TRAF3IP3 downregulation correlated with an 83% reduction of tumor growth in a subcutaneous xenograft mouse model (n=10, P=0.005). Immunohistochemistry analysis of the tumors revealed that TRAF3IP3-shRNA tumors had increased apoptosis (n=4, P<0.01) and reduced microvascular density (n=4, P<0.002). In addition, TRAF3IP3 downregulation in malignant endothelial cells reduced tube formation in a Matrigel tube formation assay. In melanoma cells, decreased levels of TRAF3IP3 were also associated with reduced viability (n=4, P=0.03) and proliferation (n=3, P=0.03), together with increased sensitivity to ultraviolet-induced apoptosis (n=4, P=0.0004). Furthermore, TRAF3IP3 downregulation correlated with increased amounts of interferon-γ. Interferon-γ inhibits tumor growth and angiogenesis, thus suggesting a new pathway for TRAF3IP3 in cancer. Collectively, the association of TRAF3IP3 with malignant properties of melanoma suggest a clinical potential for targeted therapy.

Clinical Evidence Supports a Protective Role for CXCL5 in Coronary Artery Disease.

Our goal was to measure the association of CXCL5 and molecular phenotypes associated with coronary atherosclerosis severity in patients at least 65 years old. CXCL5 is classically defined as a proinflammatory chemokine, but its role in chronic inflammatory diseases, such as coronary atherosclerosis, is not well defined. We enrolled individuals who were at least 65 years old and undergoing diagnostic cardiac catheterization. Coronary artery disease (CAD) severity was quantified in each subject via coronary angiography by calculating a CAD score. Circulating CXCL5 levels were measured from plasma, and both DNA genotyping and mRNA expression levels in peripheral blood mononuclear cells were quantified via microarray gene chips. We observed a negative association of CXCL5 levels with CAD at an odds ratio (OR) of 0.46 (95% CI, 0.27-0.75). Controlling for covariates, including sex, statin use, hypertension, hyperlipidemia, obesity, self-reported race, smoking, and diabetes, the OR was not significantly affected [OR, 0.54 (95% CI, 0.31-0.96)], consistent with a protective role for CXCL5 in coronary atherosclerosis. We also identified 18 genomic regions with expression quantitative trait loci of genes correlated with both CAD severity and circulating CXCL5 levels. Our clinical findings are consistent with the emerging link between chemokines and atherosclerosis and suggest new therapeutic targets for CAD.

Frizzled-5: a high affinity receptor for secreted frizzled-related protein-2 activation of nuclear factor of activated T-cells c3 signaling to promote angiogenesis.

Secreted frizzled-related protein 2 (SFRP2) is a pro-angiogenic factor expressed in the vasculature of a wide variety of human tumors, and modulates angiogenesis via the calcineurin-dependent nuclear factor of activated T-cells cytoplasmic 3 (NFATc3) pathway in endothelial cells. However, until now, SFRP2 receptor for this pathway was unknown. In the present study, we first used amino acid alignments and molecular modeling to demonstrate that SFRP2 interaction with frizzled-5 (FZD5) is typical of Wnt/FZD family members. To confirm this interaction, we performed co-immunofluorescence, co-immunoprecipitation, and ELISA binding assays, which demonstrated SFRP2/FZD5 binding. Functional knock-down studies further revealed that FZD5 is necessary for SFRP2-induced tube formation and intracellular calcium flux in endothelial cells. Using protein analysis on endothelial cell nuclear extracts, we also discovered that FZD5 is required for SFRP2-induced activation of NFATc3. Our novel findings reveal that FZD5 is a receptor for SFRP2 and mediates SFRP2-induced angiogenesis via calcineurin/NFATc3 pathway in endothelial cells.

Muscle ring finger 1 and muscle ring finger 2 are necessary but functionally redundant during developmental cardiac growth and regulate E2F1-mediated gene expression in vivo.

AIMS: Muscle ring finger (MuRF) proteins have been implicated in the transmission of mechanical forces to nuclear cell signaling pathways through their association with the sarcomere. We recently reported that MuRF1, but not MuRF2, regulates pathologic cardiac hypertrophy in vivo. This was surprising given that MuRF1 and MuRF2 interact with each other and many of the same sarcomeric proteins experimentally. METHODS AND RESULTS: Mice missing all four MuRF1 and MuRF2 alleles [MuRF1/MuRF2 double null (DN)] were born with a massive spontaneous hypertrophic cardiomyopathy and heart failure; mice that were null for one of the genes but heterozygous for the other (i.e. MuRF1(-/-) //MuRF2(+/-) or MuRF1(+/-) //MuRF2(-/-) ) were phenotypically identical to wild-type mice. Microarray analysis of genes differentially-expressed between MuRF1/MuRF2 DN, mice missing three of the four alleles and wild-type mice revealed a significant enrichment of genes regulated by the E2F transcription factor family. More than 85% of the differentially-expressed genes had E2F promoter regions (E2f:DP; P<0.001). Western analysis of E2F revealed no differences between MuRF1/MuRF2 DN hearts and wild-type hearts; however, chromatin immunoprecipitation studies revealed that MuRF1/MuRF2 DN hearts had significantly less binding of E2F1 in the promoter regions of genes previously defined to be regulated by E2F1 (p21, Brip1 and PDK4, P<0.01). CONCLUSIONS: These studies suggest that MuRF1 and MuRF2 play a redundant role in regulating developmental physiologic hypertrophy, by regulating E2F transcription factors essential for normal cardiac development by supporting E2F localization to the nucleus, but not through a process that degrades the transcription factor.

A novel monoclonal antibody to secreted frizzled-related protein 2 inhibits tumor growth.

Secreted frizzled-related protein 2 (SFRP2) is overexpressed in human angiosarcoma and breast cancer and stimulates angiogenesis via activation of the calcineurin/NFATc3 pathway. There are conflicting reports in the literature as to whether SFRP2 is an antagonist or agonist of ß-catenin. The aims of these studies were to assess the effects of SFRP2 antagonism on tumor growth and Wnt-signaling and to evaluate whether SFRP2 is a viable therapeutic target. The antiangiogenic and antitumor properties of SFRP2 monoclonal antibody (mAb) were assessed using in vitro proliferation, migration, tube formation assays, and in vivo angiosarcoma and triple-negative breast cancer models. Wnt-signaling was assessed in endothelial and tumor cells treated with SFRP2 mAb using Western blotting. Pharmacokinetic and biodistribution data were generated in tumor-bearing and nontumor-bearing mice. SFRP2 mAb was shown to induce antitumor and antiangiogenic effects in vitro and inhibit activation of ß-catenin and nuclear factor of activated T-cells c3 (NFATc3) in endothelial and tumor cells. Treatment of SVR angiosarcoma allografts in nude mice with the SFRP2 mAb decreased tumor volume by 58% compared with control (P = 0.004). Treatment of MDA-MB-231 breast carcinoma xenografts with SFRP2 mAb decreased tumor volume by 52% (P = 0.03) compared with control, whereas bevacizumab did not significantly reduce tumor volume. Pharmacokinetic studies show the antibody is long circulating in the blood and preferentially accumulates in SFRP2-positive tumors. In conclusion, antagonizing SFRP2 inhibits activation of ß-catenin and NFATc3 in endothelial and tumor cells and is a novel therapeutic approach for inhibiting angiosarcoma and triple-negative breast cancer.

The role of calcineurin/NFAT in SFRP2 induced angiogenesis--a rationale for breast cancer treatment with the calcineurin inhibitor tacrolimus.

Tacrolimus (FK506) is an immunosuppressive drug that binds to the immunophilin FKBPB12. The FK506-FKBP12 complex associates with calcineurin and inhibits its phosphatase activity, resulting in inhibition of nuclear translocation of nuclear factor of activated T-cells (NFAT). There is increasing data supporting a critical role of NFAT in mediating angiogenic responses stimulated by both vascular endothelial growth factor (VEGF) and a novel angiogenesis factor, secreted frizzled-related protein 2 (SFRP2). Since both VEGF and SFRP2 are expressed in breast carcinomas, we hypothesized that tacrolimus would inhibit breast carcinoma growth. Using IHC (IHC) with antibodies to FKBP12 on breast carcinomas we found that FKBP12 localizes to breast tumor vasculature. Treatment of MMTV-neu transgenic mice with tacrolimus (3 mg/kg i.p. daily) (n = 19) resulted in a 73% reduction in the growth rate for tacrolimus treated mice compared to control (n = 15), p = 0.003; which was associated with an 82% reduction in tumor microvascular density (p<0.001) by IHC. Tacrolimus (1 µM) inhibited SFRP2 induced endothelial tube formation by 71% (p = 0.005) and inhibited VEGF induced endothelial tube formation by 67% (p = 0.004). To show that NFATc3 is required for SFRP2 stimulated angiogenesis, NFATc3 was silenced with shRNA in endothelial cells. Sham transfected cells responded to SFRP2 stimulation in a tube formation assay with an increase in the number of branch points (p<0.003), however, cells transfected with shRNA to NFATc3 showed no increase in tube formation in response to SFRP2. This demonstrates that NFATc3 is required for SFRP2 induced tube formation, and tacrolimus inhibits angiogenesis in vitro and breast carcinoma growth in vivo. This provides a rationale for examining the therapeutic potential of tacrolimus at inhibiting breast carcinoma growth in humans.

Secreted frizzle-related protein 2 stimulates angiogenesis via a calcineurin/NFAT signaling pathway.

Secreted frizzle-related protein 2 (SFRP2), a modulator of Wnt signaling, has recently been found to be overexpressed in the vasculature of 85% of human breast tumors; however, its role in angiogenesis is unknown. We found that SFRP2 induced angiogenesis in the mouse Matrigel plug assay and the chick chorioallantoic membrane assay. SFRP2 inhibited hypoxia induced endothelial cell apoptosis, increased endothelial cell migration, and induced endothelial tube formation. The canonical Wnt pathway was not affected by SFRP2 in endothelial cells; however, a component of the noncanonical Wnt/Ca2+ pathway was affected by SFRP2 as shown by an increase in NFATc3 in the nuclear fraction of SFRP2-treated endothelial cells. Tacrolimus, a calcineurin inhibitor that inhibits dephosphorylation of NFAT, inhibited SFRP2-induced endothelial tube formation. Tacrolimus 3 mg/kg/d inhibited the growth of SVR angiosarcoma xenografts in mice by 46% (P = 0.04). In conclusion, SFRP2 is a novel stimulator of angiogenesis that stimulates angiogenesis via a calcineurin/NFAT pathway and may be a favorable target for the inhibition of angiogenesis in solid tumors.

Stress-dependent Daxx-CHIP interaction suppresses the p53 apoptotic program.

Our previous studies have implicated CHIP (carboxyl terminus of Hsp70-interacting protein) as a co-chaperone/ubiquitin ligase whose activities yield protection against stress-induced apoptotic events. In this report, we demonstrate a stress-dependent interaction between CHIP and Daxx (death domain-associated protein). This interaction interferes with the stress-dependent association of HIPK2 with Daxx, blocking phosphorylation of serine 46 in p53 and inhibiting the p53-dependent apoptotic program. Microarray analysis confirmed suppression of the p53-dependent transcriptional portrait in CHIP(+/+) but not in CHIP(-/-) heat shocked mouse embryonic fibroblasts. The interaction between CHIP and Daxx results in ubiquitination of Daxx, which is then partitioned to an insoluble compartment of the cell. In vitro ubiquitination of Daxx by CHIP revealed that ubiquitin chain formation utilizes non-canonical lysine linkages associated with resistance to proteasomal degradation. The ubiquitination of Daxx by CHIP utilizes lysines 630 and 631 and competes with the sumoylation machinery of the cell at these residues. These studies implicate CHIP as a stress-dependent regulator of Daxx that counters the pro-apoptotic influence of Daxx in the cell. By abrogating p53-dependent apoptotic pathways and by ubiquitination competitive with Daxx sumoylation, CHIP integrates the proteotoxic stress response of the cell with cell cycle pathways that influence cell survival.

Tobacco use induces anti-apoptotic, proliferative patterns of gene expression in circulating leukocytes of Caucasian males.

BACKGROUND: Strong epidemiologic evidence correlates tobacco use with a variety of serious adverse health effects, but the biological mechanisms that produce these effects remain elusive. RESULTS: We analyzed gene transcription data to identify expression spectra related to tobacco use in circulating leukocytes of 67 Caucasian male subjects. Levels of cotinine, a nicotine metabolite, were used as a surrogate marker for tobacco exposure. Significance Analysis of Microarray and Gene Set Analysis identified 109 genes in 16 gene sets whose transcription levels were differentially regulated by nicotine exposure. We subsequently analyzed this gene set by hyperclustering, a technique that allows the data to be clustered by both expression ratio and gene annotation (e.g. Gene Ontologies). CONCLUSION: Our results demonstrate that tobacco use affects transcription of groups of genes that are involved in proliferation and apoptosis in circulating leukocytes. These transcriptional effects include a repertoire of transcriptional changes likely to increase the incidence of neoplasia through an altered expression of genes associated with transcription and signaling, interferon responses and repression of apoptotic pathways.

Comparative effects of paclitaxel and rapamycin on smooth muscle migration and survival: role of AKT-dependent signaling.

OBJECTIVE: Advances in stent technology have enabled the delivery of drugs to improve outcomes after stent deployment. However, the optimal payloads for stents are not clear, and the appropriate stent-based therapies for high-risk patients, such as diabetics, have not been clearly established. METHODS AND RESULTS: We used smooth muscle cell culture models to compare the activities of rapamycin and paclitaxel. Smooth muscle cells were grown in normal or high glucose to induce insulin resistance. Both paclitaxel and rapamycin activate mitogen-activated protein kinase pathways similarly. However, rapamycin potently activates AKT-dependent signaling, an effect that overrides the downregulation of this pathway by insulin resistance and that causes phosphorylation of the AKT-dependent transcription factor FOXO1. This effect is associated with attenuation of the anti-migratory effects of rapamycin under high glucose conditions that are not observed with paclitaxel, as well as with increased protection against ceramide-induced cytotoxicity, both of which are dependent on FOXO1 phosphorylation. CONCLUSIONS: Differences between the ability of rapamycin and paclitaxel to activate AKT may account for their differential cell survival and antichemotactic activities. These observations may provide a basis for understanding clinical differences between rapamycin- and paclitaxel-coated stents. The approaches used in these studies can be expanded to other candidate stent payloads as a method for triage in preclinical studies.