Glycosaminoglycan modifications of betaglycan regulate ectodomain shedding to fine-tune TGF-β signaling responses in ovarian cancer

In pathologies including cancer, aberrant Transforming Growth Factor-β (TGF-β) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-β responses. Betaglycan/type III TGF-β receptor (TβRIII), is an established co-receptor for the TGF-β superfamily known to bind directly to TGF-βs 1-3 and inhibin A/B. Betaglycan can be membrane-bound and also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. Its extracellular domain undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. We report the unexpected discovery that the heparan sulfate glycosaminoglycan chains on betaglycan are critical for the ectodomain shedding. In the absence of such glycosaminoglycan chains betaglycan is not shed, a feature indispensable for the ability of betaglycan to suppress TGF-β signaling and the cells' responses to exogenous TGF-β ligands. Using unbiased transcriptomics, we identified TIMP3 as a key inhibitor of betaglycan shedding thereby influencing TGF-β signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-β signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan chains of betaglycan for shedding and influence on TGF-β signaling responses. Dysregulated shedding of TGF-β receptors plays a vital role in determining the response and availability of TGF-βs', which is crucial for prognostic predictions and understanding of TGF-β signaling dynamics.

Prognostic and predictive analyses of circulating plasma biomarkers in men with metastatic castration resistant prostate cancer treated with docetaxel/prednisone with or without bevacizumab

BACKGROUND

CALGB 90401 (Alliance) was a phase III trial of 1050 patients with metastatic castration-resistant prostate cancer (mCRPC) comparing docetaxel, prednisone, bevacizumab (DP+B) versus DP alone. While this trial did not show an improvement in overall survival (OS), there were improved intermediate outcomes suggesting that subsets of men may derive benefit from this combination. The purpose of this analysis was to identify prognostic and predictive biomarkers associated with OS and progression-free survival (PFS) benefit from DP+B.

METHODS

Baseline EDTA plasma samples from 650 consenting patients were analyzed for 24 biomarkers. The proportional hazards model was utilized to test for the prognostic and predictive importance of the biomarkers for OS. The statistically significant biomarkers of OS were further investigated for prognostic and predictive importance for other secondary outcomes.

RESULTS

15 markers [ICAM-1, VEGF-R3, TIMP-1, TSP-2, Ang-2, Her-3, Osteopontin (OPN), PlGF, VCAM-1, HGF, VEGF, Chromogranin A, IL-6, VEGF-R1, BMP-9] were prognostic of OS, while 9 markers (ICAM-1, VEGF-R3, Her-3, TIMP-1, Ang-2, OPN, PlGF, HGF, and VEGF) were also prognostic of PFS. All markers were statistically significant in univariate analyses after adjustment for multiplicity (FDR < 0.1). In multivariable analyses of OS adjusting for risk score, seven markers had FDR < 0.1, including ICAM-1, VEGF-R3, TIMP-1, Ang-2, VEGF, TSP-2 and HGF. In unadjusted analysis, OPN was predictive of PFS improvement with DP+B, in both univariate and multivariable analysis. However, none of the biomarkers tested were predictive of clinical outcomes after adjusting for multiple comparisons.

CONCLUSIONS

Multiple biomarkers were identified in CALGB 90401 as prognostic of clinical outcomes but not predictive of OS. While OPN may have promise as a potential biomarker for anti-angiogenic therapies, further mechanistic and clinical studies are needed to determine the underlying biology and potential clinical application.

Heparan sulfate modifications of betaglycan promote TIMP3-dependent ectodomain shedding to fine-tune TGF-β signaling

In pathologies such as cancer, aberrant Transforming Growth Factor-β (TGF-β) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pivotal pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-β responses. Betaglycan/type III TGF-β receptor (TβRIII), is an established co-receptor for the TGF-β superfamily known to bind directly to TGF-βs 1-3 and inhibin A/B. While betaglycan can be membrane-bound, it can also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. The extracellular domain of betaglycan undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. Here we report the unexpected discovery that the heparan sulfate modifications are critical for the ectodomain shedding of betaglycan. In the absence of such modifications, betaglycan is not shed. Such shedding is indispensable for the ability of betaglycan to suppress TGF-β signaling and the cells' responses to exogenous TGF-β ligands. Using unbiased transcriptomics, we identified TIMP3 as a key regulator of betaglycan shedding and thereby TGF-β signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-β signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan modifications of betaglycan for shedding and influence on TGF-β signaling responses. Dysregulated shedding of TGF-β receptors plays a vital role in determining the response and availability of TGF-βs', which is crucial for prognostic predictions and understanding of TGF-β signaling dynamics.

Reciprocal SOX2 regulation by SMAD1-SMAD3 is critical for anoikis resistance and metastasis in cancer

Growth factors in tumor environments are regulators of cell survival and metastasis. Here, we reveal the dichotomy between TGF-β superfamily growth factors BMP and TGF-β/activin and their downstream SMAD effectors. Gene expression profiling uncovers SOX2 as a key contextual signaling node regulated in an opposing manner by BMP2, -4, and -9 and TGF-β and activin A to impact anchorage-independent cell survival. We find that SOX2 is repressed by BMPs, leading to a reduction in intraperitoneal tumor burden and improved survival of tumor-bearing mice. Repression of SOX2 is driven by SMAD1-dependent histone H3K27me3 recruitment and DNA methylation at SOX2's promoter. Conversely, TGF-β, which is elevated in patient ascites, and activin A can promote SOX2 expression and anchorage-independent survival by SMAD3-dependent histone H3K4me3 recruitment. Our findings identify SOX2 as a contextual and contrastingly regulated node downstream of TGF-β members controlling anchorage-independent survival and metastasis in ovarian cancers.

Predictive Biomarkers of Overall Survival in Patients with Metastatic Renal Cell Carcinoma Treated with IFNα ± Bevacizumab: Results from CALGB 90206 (Alliance)

PURPOSE

CALGB 90206 was a phase III trial of 732 patients with metastatic renal cell carcinoma (mRCC) comparing bevacizumab plus IFNα (BEV + IFN) with IFNα alone (IFN). No difference in overall survival (OS) was observed. Baseline samples were analyzed to identify predictive biomarkers for survival benefit.

PATIENTS AND METHODS

A total of 32 biomarkers were assessed in 498 consenting patients randomly assigned into training (n = 279) and testing (n = 219) sets. The proportional hazards model was used to test for treatment arm and biomarker interactions of OS. The estimated coefficients from the training set were used to compute a risk score for each patient and to classify patients by risk in the testing set. The resulting model was assessed for predictive accuracy using the time-dependent area under the ROC curve (tAUROC).

RESULTS

A statistically significant three-way interaction between IL6, hepatocyte growth factor (HGF), and bevacizumab treatment was observed in the training set and confirmed in the testing set (P < 0.0001). The model based on IL6, HGF, and bevacizumab treatment was predictive of OS (P < 0.001), with the high- and low-risk groups having a median OS of 10.2 [95% confidence interval (CI), 8.0-13.8] and 34.3 (95% CI, 28.5-40.5) months, respectively. The average tAUROC for the final model of OS based on 100 randomly split testing sets was 0.78 (first, third quartiles = 0.77, 0.79).

CONCLUSIONS

IL6 and HGF are potential predictive biomarkers of OS benefit from BEV + IFN in patients with mRCC. The model based on key biological and clinical factors demonstrated predictive efficacy for OS. These markers warrant further validation in future anti-VEGF and immunotherapy in mRCC trials. See related commentaries by Mishkin and Kohn, p. 2722 and George and Bertagnolli, p. 2725.

Plasma Protein Biomarkers in Advanced or Metastatic Colorectal Cancer Patients Receiving Chemotherapy With Bevacizumab or Cetuximab: Results from CALGB 80405 (Alliance)

PURPOSE

CALGB 80405 compared the combination of first-line chemotherapy with cetuximab or bevacizumab in the treatment of advanced or metastatic colorectal cancer (mCRC). Although similar clinical outcomes were observed in the cetuximab-chemotherapy group and the bevacizumab-chemotherapy group, biomarkers could identify patients deriving more benefit from either biologic agent.

PATIENTS AND METHODS

In this exploratory analysis, the Angiome, a panel of 24 soluble protein biomarkers were measured in baseline plasma samples in CALGB 80405. Prognostic biomarkers were determined using univariate Cox proportional hazards models. Predictive biomarkers were identified using multivariable Cox regression models including interaction between biomarker level and treatment.

RESULTS

In the total population, high plasma levels of Ang-2, CD73, HGF, ICAM-1, IL6, OPN, TIMP-1, TSP-2, VCAM-1, and VEGF-R3 were identified as prognostic of worse progression-free survival (PFS) and overall survival (OS). PlGF was identified as predictive of lack of PFS benefit from bevacizumab [bevacizumab HR, 1.51; 95% confidence interval (CI), 1.10-2.06; cetuximab HR, 0.94; 95% CI, 0.71-1.25; Pinteraction = 0.0298] in the combined FOLFIRI/FOLFOX regimens. High levels of VEGF-D were predictive of lack of PFS benefit from bevacizumab in patients receiving FOLFOX regimen only (FOLFOX/bevacizumab HR, 1.70; 95% CI, 1.19-2.42; FOLFOX/cetuximab HR, 0.92; 95% CI, 0.68-1.24; Pinteraction = 0.0097).

CONCLUSIONS

In this exploratory, hypothesis-generating analysis, the Angiome identified multiple prognostic biomarkers and two potential predictive biomarkers for patients with mCRC enrolled in CALGB 80405. PlGF and VEGF-D predicted lack of benefit from bevacizumab in a chemo-dependent manner. See related commentaries by Mishkin and Kohn, p. 2722 and George and Bertagnolli, p. 2725.

Evaluating immune response and metabolic related biomarkers pre-allogenic hematopoietic stem cell transplant in acute myeloid leukemia

Although hematopoietic stem cell transplantation (HCT) is the only curative treatment for acute myeloid leukemia (AML), it is associated with significant treatment related morbidity and mortality. There is great need for predictive biomarkers associated with overall survival (OS) and clinical outcomes. We hypothesized that circulating metabolic, inflammatory, and immune molecules have potential as predictive biomarkers for AML patients who receive HCT treatment. This retrospective study was designed with an exploratory approach to comprehensively characterize immune, inflammatory, and metabolomic biomarkers. We identified patients with AML who underwent HCT and had existing baseline plasma samples. Using those samples (n = 34), we studied 65 blood based metabolomic and 61 immune/inflammatory related biomarkers, comparing patients with either long-term OS (≥ 3 years) or short-term OS (OS ≤ 1 years). We also compared the immune/inflammatory response and metabolomic biomarkers in younger vs. older AML patients (≤30 years vs. ≥ 55 years old). In addition, the biomarker profiles were analyzed for their association with clinical outcomes, namely OS, chronic graft versus host disease (cGVHD), acute graft versus host disease (aGVHD), infection and relapse. Several baseline biomarkers were elevated in older versus younger patients, and baseline levels were lower for three markers (IL13, SAA, CRP) in patients with OS ≥ 3 years. We also identified immune/inflammatory response markers associated with aGVHD (IL-9, Eotaxin-3), cGVHD (Flt-1), infection (D-dimer), or relapse (IL-17D, bFGF, Eotaxin-3). Evaluation of metabolic markers demonstrated higher baseline levels of medium- and long-chain acylcarnitines (AC) in older patients, association with aGVHD (lactate, long-chain AC), and cGVHD (medium-chain AC). These differentially expressed profiles merit further evaluation as predictive biomarkers.

Cabozantinib with or without Panitumumab for RAS wild-type metastatic colorectal cancer: impact of MET amplification on clinical outcomes and circulating biomarkers

PURPOSE

Acquired resistance to EGFR inhibitors in metastatic colorectal cancer (mCRC) remains a hurdle for effective treatment. MET amplification has been indicated as a driver of acquired resistance. Clinical activity has been demonstrated for the combination of EGFR and MET inhibitors in mCRC. But the impact of this regimen on angiogenesis and inflammation remains largely unknown.

METHODS

In this non-randomized, open-label phase Ib/II study, four patients were treated with cabozantinib alone and 25 patients received the combination of cabozantinib and panitumumab. MET amplification was detected in blood in all four patients treated with cabozantinib monotherapy and 5/25 patients treated with cabozantinib and panitumumab combination therapy. Plasma samples from 28 patients were available for biomarker analysis.

RESULTS

A panel of circulating protein biomarkers was assessed in patient plasma at baseline and on-treatment. Baseline marker levels were analyzed for prognostic value for clinical outcomes, including MET amplification as a covariate. HGF and OPN were prognostic for both progression-free survival (PFS) and overall survival (OS), while six markers (IL-6, VCAM-1, VEGF-R1, TSP-2, TIMP-1, ICAM-1) were prognostic only for OS. In patients with MET amplification, baseline PDGF-AA, PDGF-BB, TGF-β1, and VEGF-C levels were significantly higher, whereas baseline TGFβ-R3 levels were significantly lower than MET non-amplified patients. On-treatment change of four markers (CD73, PlGF, PDGF-BB, VEGF) were significantly different between MET amplified and non-amplified subpopulations.

CONCLUSION

This study identified circulating HGF and several inflammatory and angiogenic proteins as prognostic biomarkers. Furthermore, MET amplification status is associated with both baseline expression and on-treatment modulation of members of angiogenesis and TGF-β pathway proteins.

CLINICAL TRIALS REGISTRATION NUMBER

ClinicalTrials.gov identifier: NCT02008383.

Pilot investigation of circulating angiogenic and inflammatory biomarkers associated with vascular malformations

Background

Vascular malformations in the central nervous system are difficult to monitor and treat due to their inaccessible location. Angiogenic and inflammatory proteins are secreted into the bloodstream and may serve as useful biomarkers for identifying patients at risk for complications or with certain disease phenotypes.

Methods

A validated multiplex protein array consisting of 26 angiogenic and inflammatory biomarkers (Angiome) was assessed in plasma isolated from healthy controls and patients with either sporadic brain arteriovenous malformation (BAVM), familial cerebral cavernous malformation (CCM), or hereditary hemorrhagic telangiectasia (HHT). These samples were obtained from archives of ongoing research studies at the University of California San Francisco and through prospective collection at the Toronto HHT Centre at St. Michael’s Hospital.

Results

We compared circulating biomarker levels from each patient group to healthy controls and analyzed each pairwise combination of patient groups for differences in biomarker levels. Additionally, we analyzed the HHT samples to determine the association between biomarker levels and the following HHT-specific phenotypes, BAVM, pulmonary arteriovenous malformation (PAVM), liver vascular malformation (LVM), and gastrointestinal (GI) bleeding. Compared to controls, levels of SDF1 were significantly elevated in HHT patients (Proportional Increase [PI] = 1.87, p < 0.001, q = 0.011). Levels of sENG were significantly reduced in HHT patients compared to controls (PI = 0.56, p < 0.001, q < 0.001), reflecting the prevalence of HHT1 patients in this cohort. Levels of IL6 (PI = 3.22, p < 0.001, q < 0.001) and sTGFβR3 (PI = 0.70, p = 0.001, q < 0.029) differed significantly in CCM patients compared to controls. Compared to controls, ten of the biomarkers were significantly different in sporadic BAVM patients (q-values < 0.05). Among the pairwise combinations of patient groups, a significant elevation was observed in TGFβ1 in CCM patients compared to sporadic BAVM patients (PI = 2.30, p < 0.001, q = 0.034). When examining the association of circulating biomarker levels with HHT-specific phenotypes, four markers were significantly lower in HHT patients with BAVM (q-values < 0.05), and four markers were significantly higher in patients with LVM (q-values < 0.05).

Conclusions

This pilot study suggests that the profile of circulating angiogenic and inflammatory biomarkers may be unique to each type of vascular malformation. Furthermore, this study indicates that circulating biomarkers may be useful for assessing phenotypic traits of vascular malformations.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02009-7.

Identification of prognostic and predictive biomarkers of overall survival (OS) and progression-free survival (PFS) in patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) treated with docetaxel, prednisone (DP) +/- bevacizumab (B) in CALGB 90401 (Alliance)

154

Background: CALGB 90401 was a phase III trial of 1050 pts with mCRPC comparing DP+B versus DP alone. While this trial did not show an improvement in OS in the overall population, there were improved PSA response, objective responses and delays in progression suggesting that subsets of men may derive benefit from this combination The purpose of this analysis was to identify and validate plasma angiokines (PAs) that are prognostic or predictive of OS and PFS benefit from bevacizumab in men with mCRPC. Methods: Baseline EDTA plasma samples from 679 consenting pts were analyzed using an optimized multiplex ELISA platform for 25 PAs related to tumor growth, angiogenesis, and inflammation. The data were randomly split into training (n = 462) and testing (n = 217) sets. The proportional hazards model was utilized to test for the prognostic and predictive importance of the PAs in predicting OS and PFS, with and without adjustment for clinical risk score. Analyses were adjusted for multiplicity using false discovery rate (FDR). Results: For the prognostic analysis, 14 PAs (angiopoeitin-2, BMP9, Chromogranin A, HER3, HGF, ICAM-1, IL6, OPN, PIGF, TIMP, TSP2, VEGFA, VEGFR1, and VEGF-R3) were prognostic of OS and 8 PAs (angiopoietin-2, HER3, ICAM-1, IL6, OPN, TIMP, VEGFA and VEGF-R3) were prognostic of PFS in the training set (FDR < 0.05). None of the PAs were statistically significant for OS or PFS when adjusting by the clinical risk score, suggesting that angiokine levels associate with clinical prognostic factors. OPN was predictive of OS in the training set but no other PAs were found to be predictive of PFS improvement with DP+B. Using the testing set, we were unable to validate that OPN is predictive of OS/PFS or any of the PAs are predictive biomarkers of the OS or PFS benefits of DP+B over DP alone in men with mCRPC. Conclusions: While PAs are prognostic for OS and PFS in univariate analysis, we were unable to validate the results in the testing set. Furthermore, we did not identify any PAs that are predictive of benefit from the addition of bevacizumab to docetaxel/prednisone with ADT in this setting. Nevertheless, these remain worthy of further evaluation as potential therapeutic targets.

Prognostic and Predictive Biomarkers in Patients with Metastatic Colorectal Cancer Receiving Regorafenib

Regorafenib is a tyrosine kinase inhibitor approved by the FDA for the treatment of patients with chemotherapy refractory metastatic colorectal cancer (mCRC). Regorafenib inhibits signaling through multiple receptors associated with angiogenesis, metastasis, and tumor immunity. Here, we report biomarker results from LCCC1029, a randomized, placebo-controlled, phase II trial of chemotherapy ± regorafenib in patients with second-line mCRC. A panel of 20 soluble protein biomarkers (termed the Angiome) was assessed in the plasma of 149 patients from the LCCC1029 trial both at baseline and along the treatment continuum. Baseline protein levels were analyzed for prognostic and predictive value for progression-free survival (PFS) and overall survival (OS). Changes in protein levels during treatment were analyzed for potential pharmacodynamic effects. Six markers (HGF, IL6, PlGF, VEGF-R1, OPN, and IL6R) were found to be prognostic for PFS. Nine markers (IL6, TIMP-1, PlGF, VCAM-1, ICAM-1, OPN, TSP-2, HGF, and VEGF-R1) were prognostic for OS. Higher baseline levels of OPN (P _intx = 0.0167), VCAM-1 (P _intx = 0.0216), and PDGF-AA (P _intx = 0.0435) appeared to predict for PFS benefit from regorafenib compared with placebo. VCAM-1 was also potentially predictive of OS benefit from regorafenib compared with placebo (P _intx = 0.0124). On-treatment changes of six markers reflected potential on-target effect of regorafenib. Consistent results were observed in an Italian cohort where 105 patients with late-stage mCRC received regorafenib monotherapy. The key findings of this study suggest that VCAM-1 may be a predictive biomarker for regorafenib benefit, while multiple protein markers may be prognostic of outcome in patients with mCRC.

Predictive Blood-Based Biomarkers in Patients with Epithelial Ovarian Cancer Treated with Carboplatin and Paclitaxel with or without Bevacizumab: Results from GOG-0218

PURPOSE

GOG-0218, a double-blind placebo-controlled phase III trial, compared carboplatin and paclitaxel with placebo, bevacizumab followed by placebo, or bevacizumab followed by bevacizumab in advanced epithelial ovarian cancer (EOC). Results demonstrated significantly improved progression-free survival (PFS), but no overall survival (OS) benefit with bevacizumab. Blood samples were collected for biomarker analyses.

EXPERIMENTAL DESIGN

Plasma samples were analyzed via multiplex ELISA technology for seven prespecified biomarkers [IL6, Ang-2, osteopontin (OPN), stromal cell-derived factor-1 (SDF-1), VEGF-D, IL6 receptor (IL6R), and GP130]. The predictive value of each biomarker with respect to PFS and OS was assessed using a protein marker by treatment interaction term within the framework of a Cox proportional hazards model. Prognostic markers were identified using Cox models adjusted for baseline covariates.

RESULTS

Baseline samples were available from 751 patients. According to our prespecified analysis plan, IL6 was predictive of a therapeutic advantage with bevacizumab for PFS (P = 0.007) and OS (P = 0.003). IL6 and OPN were found to be negative prognostic markers for both PFS and OS (P < 0.001). Patients with high median IL6 levels (dichotomized at the median) treated with bevacizumab had longer PFS (14.2 vs. 8.7 months) and OS (39.6 vs. 33.1 months) compared with placebo.

CONCLUSIONS

The inflammatory cytokine IL6 may be predictive of therapeutic benefit from bevacizumab when combined with carboplatin and paclitaxel. Aligning with results observed in patients with renal cancer treated with antiangiogenic therapies, it appears plasma IL6 may also define those patients with EOC more or less likely to benefit from the addition of bevacizumab to standard chemotherapy.

Longitudinal multiplex cytokine analysis for patients (pts) with metastatic renal cell carcinoma (mRCC) treated with ipilimumab/nivolumab (I+N)

731

Background: I+N is an established treatment for mRCC, where circulating protein biomarkers are prognostic. In a longitudinal correlative study, we characterized circulating proteins in mRCC pts treated with standard of care I+N. Methods: mRCC pts treated with I+N were prospectively enrolled at Duke Cancer Institute (NCT02978118), contributing EDTA plasma at baseline, week(wk)-4, wk-12, and disease progression. Best overall responses were characterized as disease control (DC; stable disease, partial & complete responses) versus progressive disease (PD). Plasma was batch analyzed using a 46-plex MesoScale Discovery ELISA assay (IFN-g, interleukins [IL]-1b, 2, 4, 5, 6, 7, 8, 10, 12, IL-12-IL-23p40, 13, 15, 16, 17A, 21, 22, 27, 31, MIP-3a, Eotaxin, Eotaxin-3, IP-10, MCP-1&4, MDC, MIP-1a & 1b, TARC, TNF-a & b, GM-CSF, CRP, ICAM-1, SAA, VCAM-1, FGFb, FLT-1, PlGF, Tie-2, VEGF, VEGF-, and VEGF-D). Mean and standard deviations of cytokine concentrations are reported, along with a Wilcoxon rank sum test between PD and DC groups; unadjusted p-values are nominal. Results: We enrolled 25 pts with mRCC (15 DC and 10 PD). Baseline IL-7, IL-8, IL-12-IL-23p40, ICAM-1, TNF-a, VEGF-C, and VEGF-D were lower in PD pts than DC pts (Table). MIP-1b was significantly lower for PD than DC pts at baseline (Table) and wk-4 change (PD 0.30 +/- 1.82, DC 0.83 +/- 6.49, p = 0.056). Although baseline IFN-g did not differ between groups, wk-4 IFN-g significantly increased in DC and decreased in PD pts (DC 3.5 +/- 7.1; PD -1.33 +/- 5.47, p = 0.056). Conclusions: In this pilot exploratory analysis, a subset of ILs are higher at baseline in DC than PD pts. A wk-4 increase in circulating IFN-g is associated with DC vs PD and could be linked to increased early inflammation and response to I+N. Larger prospective studies are needed to validate these findings.[Table: see text]

On-treatment changes of plasma protein biomarkers in CALGB/SWOG 80405 (Alliance)

588

Background: CALGB/SWOG 80405 found no difference in overall survival (OS) or progression-free survival (PFS) in 1137 patients with KRAS wild-type metastatic colorectal cancer (mCRC) treated with either the anti-VEGF agent bevacizumab (Bev) or the anti-EGFR agent cetuximab (Cet) in combination with chemotherapy (FOLFOX or FOLFIRI) as first-line therapy. Additional molecular biomarkers are required for the optimization of treatment choices for patients with mCRC. Methods: Levels of 24 proteins were assayed in EDTA-plasma samples using multiplex ELISA techniques. Plasma samples were collected at baseline and cycle 2 day 1 (C2D1). Analyses of baseline markers have been presented previously. Changes from baseline to C2D1 were expressed as an L-ratio (LR, log2 of C2D1 divided by baseline measure). LRs dichotomized at 0 were analyzed for potential prognostic and predictive effects on OS and PFS using Cox models while adjusting for confounders (post-hoc optimized cutpoints were used for PLGF, TIMP1, VCAM1, and VEGFR3 due to skew in the distributions of these markers). P-values are not corrected for multiple testing. Results: Baseline and matched C2D1 samples from 446 patients (212 Bev/234 Cet) were available for analysis. Thirteen markers were differentially modulated between arms (p < 0.05). Early increases in CD73 (p = 0.001), ICAM1 (p = 0.022), TIMP1 (p = 0.001), TSP2 (p = 0.024), and VEGFR3 (p = 0.006) were prognostic for shorter OS. Increases in ICAM1 (p = 0.008), TIMP1 (p = 0.042), and TGFB1 (p = 0.039) were prognostic for shorter PFS. Changes in VEGFR3 (pint = 0.097) and TGFBR3 (pint = 0.052) were predictive for OS and PFS, respectively. No other markers were predictive for OS or PFS (p < 0.1). Conclusions: Changes in circulating plasma protein biomarkers observed in patients enrolled in CALGB/SWOG 80405 were both prognostic and predictive for OS and PFS and warrant further study. Such changes could provide valuable information and help guide treatment decisions. Support: U10CA180821, U10CA180882, U10CA180888, U10CA180830; ClinicalTrials.gov: NCT00265850. [Table: see text]

Blood-based biomarkers in metastatic colorectal cancer patients treated with FOLFIRI plus regorafenib or placebo: Results from LCCC1029

587

Background: The LCCC1029 trial demonstrated that addition of the multitargeted kinase inhibitor regorafenib (Rego) to FOLFIRI in metastatic colorectal cancer (mCRC) patients (pts) modestly prolonged progression-free survival (PFS). In this preplanned analysis, circulating angiogenic and inflammatory proteins were explored as potential prognostic and predictive biomarkers of Rego benefit. Methods: Plasma samples from 149 mCRC pts (107 in Rego + FOLFIRI and 42 in placebo + FOLFIRI) were evaluated for 20 markers at baseline (n = 149) and cycle 1 day 21 (C1D21, n = 81). Predictive and prognostic values of each marker at baseline were analyzed for both PFS and overall survival (OS) using Cox proportional hazard models. On-treatment changes were quantified as fold change [log2(C1D21/baseline)] and differences between arms were evaluated using the Mann-Whitney test. Results: The primary objective of this study was to determine whether any marker was predictive of benefit with Rego for PFS. Although no treatment by marker interactions were significant after adjusting for multiple testing, the top three markers of interest were OPN (unadjusted p-values of 0.02), VCAM-1 (0.02), and PDGF-AA (0.04). VCAM-1 was also predictive for OS benefit in pts treated with Rego (unadjusted p = 0.01). Baseline levels of multiple markers (including HGF, IL-6, PlGF, VEGF-R1, OPN) were prognostic for both PFS and OS. Higher levels of these markers were associated with worse survival. Biomarker changes in response to treatment were explored and compared between arms. Fold change of three markers (PlGF, VEGF-A, VCAM-1) were significantly different between arms (p < 0.0001), all being markedly up-regulated in the Rego arm compared to the placebo after treatment. Conclusions: In this hypothesis generating report, VCAM-1, OPN, and PDGF-AA were the top biomarkers when analyzing the potential predictive association with PFS, where a lower hazard was observed for pts receiving Rego. Candidate prognostic markers were identified, including PlGF and VEGF-R1, key factors in VEGF biology. Biomarker changes observed here may offer insights into potential combinatorial strategies with Rego for future studies.

TGF-β-induced stromal CYR61 promotes resistance to gemcitabine in pancreatic ductal adenocarcinoma through downregulation of the nucleoside transporters hENT1 and hCNT3

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer in part due to inherent resistance to chemotherapy, including the first-line drug gemcitabine. Although low expression of the nucleoside transporters hENT1 and hCNT3 that mediate cellular uptake of gemcitabine has been linked to gemcitabine resistance, the mechanisms regulating their expression in the PDAC tumor microenvironment are largely unknown. Here, we report that the matricellular protein cysteine-rich angiogenic inducer 61 (CYR61) negatively regulates the nucleoside transporters hENT1 and hCNT3. CRISPR/Cas9-mediated knockout of CYR61 increased expression of hENT1 and hCNT3, increased cellular uptake of gemcitabine and sensitized PDAC cells to gemcitabine-induced apoptosis. In PDAC patient samples, expression of hENT1 and hCNT3 negatively correlates with expression of CYR61 . We demonstrate that stromal pancreatic stellate cells (PSCs) are a source of CYR61 within the PDAC tumor microenvironment. Transforming growth factor-β (TGF-β) induces the expression of CYR61 in PSCs through canonical TGF-β-ALK5-Smad2/3 signaling. Activation of TGF-β signaling or expression of CYR61 in PSCs promotes resistance to gemcitabine in PDAC cells in an in vitro co-culture assay. Our results identify CYR61 as a TGF-β-induced stromal-derived factor that regulates gemcitabine sensitivity in PDAC and suggest that targeting CYR61 may improve chemotherapy response in PDAC patients.

Pilot Evaluation of Angiogenesis Signaling Factor Response after Transcatheter Arterial Embolization for Hepatocellular Carcinoma

Purpose To identify changes in a broad panel of circulating angiogenesis factors after bland transcatheter arterial embolization (TAE), a purely ischemic treatment for hepatocellular carcinoma (HCC). Materials and Methods This prospective HIPAA-compliant study was approved by the institutional review board. Informed written consent was obtained from all participants prior to entry into the study. Twenty-five patients (21 men; mean age, 61 years; range, 30-81 years) with Liver Imaging Reporting and Data System category 5 or biopsy-proven HCC and who were undergoing TAE were enrolled from October 15, 2014, through December 2, 2015. Nineteen plasma angiogenesis factors (angiopoietin 2; hepatocyte growth factor; platelet-derived growth factor AA and BB; placental growth factor; vascular endothelial growth factor A and D; vascular endothelial growth factor receptor 1, 2, and 3; osteopontin; transforming growth factor β1 and β2; thrombospondin 2; intercellular adhesion molecule 1; interleukin 6 [IL-6]; stromal cell-derived factor 1; tissue inhibitor of metalloproteinases 1; and vascular cell adhesion molecule 1 [VCAM-1]) were measured by using enzyme-linked immunosorbent assays at 1 day, 2 weeks, and 5 weeks after TAE and were compared with baseline levels by using paired Wilcoxon tests. Tumor response was assessed according to modified Response Evaluation Criteria in Solid Tumors (mRECIST). Angiogenesis factor levels were compared between responders and nonresponders by mRECIST criteria by using unpaired Wilcoxon tests. Results All procedures were technically successful with no complications. Fourteen angiogenesis factors showed statistically significant changes following TAE, but most changes were transient. IL-6 was upregulated only 1 day after the procedure, but showed the largest increases of any factor. Osteopontin and VCAM-1 demonstrated sustained upregulation at all time points following TAE. At 3-month follow-up imaging, 11 patients had responses to TAE (complete response, n = 6; partial response, n = 5) and 11 patients were nonresponders (stable disease, n = 9; progressive disease, n = 2). In nonresponders, the percent change in IL-6 on the day after TAE (P = .033) and the mean percent change in osteopontin after TAE (P = .024) were significantly greater compared with those of responders. Conclusion Multiple angiogenesis factors demonstrated significant upregulation after TAE. VCAM-1 and osteopontin demonstrated sustained upregulation, whereas the rest were transient. IL-6 and osteopontin correlated significantly with radiologic response after TAE. ^© RSNA, 2017.

Association of on-treatment plasma HGF levels with overall survival (OS) in patients (pts) with advanced renal cell carcinoma (RCC) treated with interferon alpha (INF) +/- bevacizumab (BEV): Results from CALGB 90206 (Alliance)

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Background: Elevated baseline HGF levels were associated with shorter OS in pts treated with BEV+INF. We evaluated on-treatment HGF levels to describe treatment-related changes and associations with outcome. Methods: We analyzed baseline EDTA plasma samples from 310 pts (148 INF; 162 BEV+INF) using an optimized multiplex ELISA platform for HGF at baseline and after 4-weeks (wks) on treatment. Primary endpoint of this analysis was OS. The Kaplan-Meier estimated the OS distribution and the proportional hazards model tested the prognostic importance of change at 4-wks from baseline in HGF levels in predicting OS, adjusting for treatment arm, bone metastases and stratification variables. Results: The median baseline HGF level in 310 pts was 161.4 pg/ml. Elevated HGF at 4-wks (>median) was associated with a worse OS (median OS = 14 vs 27 months; adjusted hazard ratio (HR)= 1.75, p< 0.0001). Only 9/155 pts (5.8%) with baseline HGF levels ≤ median developed elevated HGF (>median) at 4-wks; 66/155 pts (43%) with baseline HGF levels >median lowered HGF (<median) at 4-wks from baseline. Compared to pts with persistently elevated HGF levels, a decline in HGF levels at 4-wks (< median) was associated with improved OS (19 vs 13 months, adjusted HR=1.41, p=0.043). Conclusions: In RCC pts with low baseline HGF levels (< median), levels remain consistently low and are associated with improved OS. Conversely, in pts with high baseline HGF levels results are split; some patients continue to have high levels on treatment and are associated with a worse OS, suggesting that, HGF predicts for therapeutic benefit and represents a potential mechanism of resistance. Support: U10CA180821, U10CA180882. Clinical trial information: NCT00072046 .

Biomarker modulation in patients treated with TRC105 in combination with anti-VEGF therapy

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Background: TRC105, an endoglin-targeting monoclonal antibody with anti-angiogenic and anti-tumor activity, is being evaluated in multiple diseases. Here we report on pharmacodynamic and prognostic biomarkers in patients (pts) treated with both TRC105 and anti-VEGF agents. Methods: Plasma samples were collected from pts on three phase 2 trials combining TRC105 with an anti-VEGF agent: axitinib in metastatic renal cell carcinoma (mRCC), pazopanib in advanced soft tissue sarcoma, and bevacizumab in glioblastoma (GBM). Baseline and on-treatment levels of 22 soluble protein biomarkers were assessed. Results: Soluble endoglin markedly increased after TRC105 treatment in all pts ( p< 0.001) as previously reported. BMP9 (a ligand for endoglin) and TGFβR3 (a type III TGFβ receptor) decreased in sarcoma pts at Cycle 2 Day 1 (C2D1) and generally remained below baseline throughout the course of treatment (BMP9, p= 0.004; TGFβR3, p= 0.003). Although TGFβR3 was decreased at C2D1 in mRCC (p = 0.030), no clear patterns were observed over time. Overall BMP9 levels did not change in response to therapy in either mRCC or GBM. Osteopontin (OPN) levels, a downstream effector of TGFβ signaling, were increased in sarcoma pts [ p= 0.002 at C2D15, p< 0.001 at C4D1 and end of study (EOS)]; however, in mRCC ( p= 0.010) and GBM ( p= 0.003), OPN was only elevated at EOS. Increases in PlGF and VEGFD, and decreases in VEGFR2 were observed across all studies, as previously noted for VEGF inhibitors. In the mRCC trial, 5 of 18 pts exhibited a ≥30% tumor reduction. Lower OPN ( p= 0.026) and higher TGFβR3 ( p= 0.003) levels at baseline correlated with radiographic response to treatment. In the sarcoma trial, 6 of 19 pts responded (CHOI criteria) in which lower baseline levels of ICAM1 ( p= 0.018) and TSP2 ( p= 0.042) correlated with stable disease. Conclusions: In these trials, increases of soluble endoglin in response to TRC105 were observed, independent of the presence of any specific VEGF inhibitor. Differential regulation of BMP9, TGFβR3, and OPN suggests potential disease-specific modulation of key TGFβ signaling molecules in response to dual therapy. Baseline levels of OPN and TGFβR3 showed potential prognostic value in mRCC. Confirmation in larger trials is needed.

Blood-based markers of efficacy and resistance to cetuximab treatment in metastatic colorectal cancer: results from CALGB 80203 (Alliance)

Circulating protein markers were assessed in patients with colorectal cancer (CRC) treated with cetuximab in CALGB 80203 to identify prognostic and predictive biomarkers. Patients with locally advanced or metastatic CRC received FOLFOX or FOLFIRI chemotherapy (chemo) or chemo in combination with cetuximab. Baseline plasma samples from 152 patients were analyzed for six candidate markers [epidermal growth factor (EGF), heparin‐binding EGF (HBEGF), epidermal growth factor receptor (EGFR), HER2, HER3, and CD73]. Analyte levels were associated with survival endpoints using univariate Cox proportional hazards models. Predictive markers were identified using a treatment‐by‐marker interaction term in the Cox model. Plasma levels of EGF, HBEGF, HER3, and CD73 were prognostic for overall survival (OS) across all patients (KRAS mutant and wild‐type). High levels of EGF predicted for lack of OS benefit from cetuximab in KRAS wild‐type (WT) patients (chemo HR = 0.98, 95% CI = 0.74–1.29; chemo+cetuximab HR = 1.54, 95% CI = 1.05–2.25; interaction P = 0.045) and benefit from cetuximab in KRAS mutant patients (chemo HR = 1.72, 95% CI = 1.02–2.92; chemo+cetuximab HR = 0.90, 95% CI = 0.67–1.21; interaction P = 0.026). Across all patients, higher HER3 levels were associated with significant OS benefit from cetuximab treatment (chemo HR = 4.82, 95% CI = 1.68–13.84; chemo+cetuximab HR = 0.95, 95% CI = 0.31–2.95; interaction P = 0.046). CD73 was also identified as predictive of OS benefit in KRASWT patients (chemo HR = 1.28, 95% CI = 0.88–1.84; chemo+cetuximab HR = 0.60, 95% CI = 0.32–1.13; interaction P = 0.049). Although these results are preliminary, and confirmatory studies are necessary before clinical application, the data suggest that HER3 and CD73 may play important roles in the biological response to cetuximab.

The balance of cell surface and soluble type III TGF-β receptor regulates BMP signaling in normal and cancerous mammary epithelial cells

Bone morphogenetic proteins (BMPs) are members of the TGF-β superfamily that are over-expressed in breast cancer, with context dependent effects on breast cancer pathogenesis. The type III TGF-β receptor (TβRIII) mediates BMP signaling. While TβRIII expression is lost during breast cancer progression, the role of TβRIII in regulating BMP signaling in normal mammary epithelium and breast cancer cells has not been examined. Restoring TβRIII expression in a 4T1 murine syngeneic model of breast cancer suppressed Smad1/5/8 phosphorylation and inhibited the expression of the BMP transcriptional targets, Id1 and Smad6, in vivo. Similarly, restoring TβRIII expression in human breast cancer cell lines or treatment with sTβRIII inhibited BMP-induced Smad1/5/8 phosphorylation and BMP-stimulated migration and invasion. In normal mammary epithelial cells, shRNA-mediated silencing of TβRIII, TβRIII over-expression, or treatment with sTβRIII inhibited BMP-mediated phosphorylation of Smad1/5/8 and BMP induced migration. Inhibition of TβRIII shedding through treatment with TAPI-2 or expression of a non-shedding TβRIII mutant rescued TβRIII mediated inhibition of BMP induced Smad1/5/8 phosphorylation and BMP induced migration and/or invasion in both in normal mammary epithelial cells and breast cancer cells. Conversely, expression of a TβRIII mutant, which exhibited increased shedding, significantly reduced BMP-mediated Smad1/5/8 phosphorylation, migration, and invasion. These data demonstrate that TβRIII regulates BMP-mediated signaling and biological effects, primarily through the ligand sequestration effects of sTβRIII in normal and cancerous mammary epithelial cells and suggest that the ratio of membrane bound versus sTβRIII plays an important role in mediating these effects.

Biomarker signatures correlate with clinical outcome in refractory metastatic colorectal cancer patients receiving bevacizumab and everolimus

A novel combination of bevacizumab and everolimus was evaluated in refractory colorectal cancer patients in a phase II trial. In this retrospective analysis, plasma samples from 49 patients were tested for over 40 biomarkers at baseline and after one or two cycles of drug administration. Analyte levels at baseline and change on-treatment were correlated with progression-free survival (PFS) and overall survival (OS) using univariate Cox proportional hazard modeling. Multivariable analyses were conducted using Cox modeling. Significant changes in multiple markers were observed following bevacizumab and everolimus treatment. Baseline levels of six markers significantly correlated with PFS and OS, including CRP, Gro-α, IGFBP-1, TF, ICAM-1, and TSP-2 (P < 0.05). At C2D1, changes of IGFBP-3, TGFβ-R3, and IGFBP-2 correlated with PFS and OS. Prognostic models were developed for OS and PFS (P = 0.0002 and 0.004, respectively). The baseline model for OS consisted of CRP, Gro-α, and TF, while the on-treatment model at C2D1 included IGFBP-2, IGFBP-3, and TGFβ-R3. These data demonstrated that multiple biomarkers were significantly modulated in response to bevacizumab and everolimus. Several markers correlated with both PFS and OS. Interestingly, these markers are known to be associated with inflammation and IGF signaling, key modulators of mTOR biology.

Coagulation factors in citrated plasma predict for benefit from bevacizumab (B) in patients with advanced pancreatic cancer (APC): Results from CALGB 80303 (Alliance)

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Background: CALGB 80303 evaluated gemcitabine (G) in combination with either B or placebo (P) in 602 patients (pts) with APC. No significant difference in overall survival (OS) between treatment arms was observed. Previously, plasma EDTA samples from CALGB 80303 were analyzed and potential predictive biomarkers for B were identified. This follow-up analysis evaluated citrated plasma samples for circulating proteins related to matrix remodeling and coagulation. Methods: Multiplex ELISA analysis was employed to assess the following circulating factors: E-selectin, matrix metalloprotease (MMP) 2, MMP9, von Willebrand factor (vWF), D-dimer, thrombospondin 1, and tissue factor (TF). Thrombin-antithrombin complex (TAT) was analyzed using a standard enzyme immunoassay. Prognostic characteristics were determined by associating baseline values with OS using a Cox model. Predictive markers were identified with inclusion of a treatment by marker interaction term. Results: Baseline citrated plasma samples from 109 pts were included in this analysis (59 pts G+P; 50 pts G+B). Negative prognostic factors for OS were identified, including E-selectin (p <0.01) for patients receiving G-based therapy, and E-selectin, TF, and vWF (p <0.05) in pts receiving G+P. Potential biomarkers predicting for OS benefit from B were also identified. Pts with low (< median) levels of TAT (interaction p=0.034) exhibited a median OS of 6.0 months (mo) vs. 8.3 mo (HR=0.49; 95%CI 0.28-0.88) when receiving G+P vs. G+B, respectively. Furthermore, pts with elevated levels of TF (>Q3) were found to benefit from B (interaction p=0.021), with median OS of 4.3 mo vs 4.8 mo (HR=0.44;95%CI 0.18-1.08), respectively. Longitudinal analysis of samples collected at baseline and at cycle 3 indicated that only vWF changed in pts receiving G+P, with an increase in vWF (p<0.05). Conclusions: In patients with APC, baseline levels of TAT and TF were identified as potential predictors of benefit from B. These data emphasize the importance of coagulation factors in modulating tumor angiogenesis. The potential predictive value of these factors warrants further validation.

A Phase I/biomarker study of bevacizumab in combination with CNTO 95 in patients with advanced solid tumors

PURPOSE

Inhibition of tumor angiogenesis is an effective mechanism to limit tumor growth; dual inhibition may result in additional benefit. Bevacizumab is a monoclonal antibody directed against vascular endothelial growth factor (VEGF), and intetumumab is a fully humanized monoclonal antibody that blocks αv integrins when complexed with β integrins. We evaluated the safety, tolerability, and efficacy of the combination of bevacizumab plus intetumumab in patients with refractory solid tumors. We also explored the effects of these agents on plasma-based biomarkers and wound angiogenesis.

METHODS

Patients with refractory solid tumors, Karnofsky performance status ≥70%, and adequate organ function were eligible. Plasma samples and wound biopsies were obtained at baseline and on-treatment.

RESULTS

Twelve patients were enrolled and received study drug. No tumor responses were noted. Observed toxicities included three cases of transient uveitis likely related to intetumumab and one case of reversible posterior leukoencephalopathy syndrome likely related to bevacizumab. Biomarker analysis revealed changes in soluble endoglin, soluble E-cadherin, and soluble E-selectin as well as PlGF and VEGF-D while on treatment. There was no observed impact of bevacizumab plus intetumumab on the phosphorylated or total levels of paxillin in wound tissue; however, an increase in the ratio of phospho/total paxillin levels was noted.

CONCLUSIONS

Bevacizumab and intetumumab can be administered safely in combination. Bevacizumab plus intetumumab treatment resulted in changes in the plasma levels of several extracellular matrix interacting proteins and angiogenic factors.

Abstract 2674: Stroma biology identifies heparins as differentiating agents in neuroblastoma

The neuroblastoma tumor stroma is thought to suppress neuroblast growth via release of soluble differentiating factors. Here we identify these factors and design a novel therapy based on their mechanism of action. We show that expression of heparan-sulfate proteoglycan co-receptors (HSPGs), including TβRIII, GPC1, GPC3, SDC3, and SDC4, is decreased in neuroblasts, localized to the stroma and correlates with improved prognosis. Treatment with soluble HSPGs promoted neuroblast differentiation via FGFR1, Erk, and Id1. HSPGs also enhanced differentiation from FGF2 released by the stroma. The anticoagulant heparin had similar differentiating effects, leading to decreased neuroblast proliferation. Dissection of individual sulfation sites identified 2-O, 3-O-de-sulfated heparin (ODSH) as a differentiating agent that suppressed orthotopic xenograft growth while avoiding anticoagulation. These studies uncover the critical components of the differentiating stroma secretome in neuroblastoma and the central mechanism by which they act. We translate these biologic insights into novel prognostic and therapeutic biomarkers, as well as therapeutic differentiation strategies for clinical development. More generally, our work demonstrates that tumor stroma biology can inform design of targeted molecular therapeutics.

Citation Format: Erik H. Knelson, Angela L. Gaviglio, Jasmine C. Nee, Mark D. Starr, Andrew B. Nixon, Stephen G. Marcus, Gerard C. Blobe. Stroma biology identifies heparins as differentiating agents in neuroblastoma. [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 2674. doi:10.1158/1538-7445.AM2014-2674

Stromal heparan sulfate differentiates neuroblasts to suppress neuroblastoma growth

Neuroblastoma prognosis is dependent on both the differentiation state and stromal content of the tumor. Neuroblastoma tumor stroma is thought to suppress neuroblast growth via release of soluble differentiating factors. Here, we identified critical growth-limiting components of the differentiating stroma secretome and designed a potential therapeutic strategy based on their central mechanism of action. We demonstrated that expression of heparan sulfate proteoglycans (HSPGs), including TβRIII, GPC1, GPC3, SDC3, and SDC4, is low in neuroblasts and high in the Schwannian stroma. Evaluation of neuroblastoma patient microarray data revealed an association between TGFBR3, GPC1, and SDC3 expression and improved prognosis. Treatment of neuroblastoma cell lines with soluble HSPGs promoted neuroblast differentiation via FGFR1 and ERK phosphorylation, leading to upregulation of the transcription factor inhibitor of DNA binding 1 (ID1). HSPGs also enhanced FGF2-dependent differentiation, and the anticoagulant heparin had a similar effect, leading to decreased neuroblast proliferation. Dissection of individual sulfation sites identified 2-O, 3-O-desulfated heparin (ODSH) as a differentiating agent, and treatment of orthotopic xenograft models with ODSH suppressed tumor growth and metastasis without anticoagulation. These studies support heparan sulfate signaling intermediates as prognostic and therapeutic neuroblastoma biomarkers and demonstrate that tumor stroma biology can inform the design of targeted molecular therapeutics.

Modulation of circulating protein biomarkers following TRC105 (anti-endoglin antibody) treatment in patients with advanced cancer

TRC105 is an endoglin-targeting drug that possesses anti-angiogenic and antitumor potential. Analysis of the initial phase I trial of TRC105 demonstrated good tolerability and efficacy in cancer patients. In this report, we analyzed multiple circulating biomarkers at baseline, cycle 2 day 1 (C2D1), and end of study (EOS) for each patient. The baseline level and the fold change from baseline to both C2D1 and EOS for each marker were statistically analyzed. At C2D1, seven markers were significantly downregulated (angiopoietin-2 [Ang-2], insulin-like growth factor-binding protein-3 [IGFBP-3], plasminogen activator inhibitor-1 [PAI-1] total, platelet-derived growth factor [PDGF]-AA, PDGF-BB, thrombospondin-1 [TSP-1], and vascular endothelial growth factor [VEGF]-D). Meanwhile, seven markers were upregulated by C2D1 (E-Cadherin, soluble Endoglin [sEnd], E-Selectin, interleukin-6 [IL-6], osteopontin [OPN], TSP-2, and von Willebrand factor [vWF]). At EOS, seven markers were upregulated including Ang-2, C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM-1), IGFBP-1, IL-6, TSP-2, and vascular cell adhesion molecule-1 (VCAM-1). A statistical trend was also seen for increases of VEGF-A and placenta growth factor (PlGF) at EOS. Throughout treatment, sEnd levels significantly increased, an observation that was recapitulated in cultured endothelial cells. This is the first report of plasma-based biomarkers in patients receiving TRC105. TRC105 treatment by C2D1 was associated with decreases in several angiogenic factors, including Ang-2, PDGF isoforms, and VEGF isoforms, offering insight into the mechanisms underlying TRC105's anti-angiogenic, antitumor function. Increases in sEnd were the most significant of all observed biomarker changes and may reflect direct drug effects. Additionally, biomarker changes in response to TRC105 are distinct from those seen in patients treated with VEGF-targeting drugs, suggesting the possible utility of combining these two classes of angiogenesis inhibitors in patients.

Prognostic and predictive blood-based biomarkers of overall survival (OS) in patients (pts) with advanced colorectal cancer (CRC) treated with cetuximab (C): Results from CALGB 80203 (Alliance)

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Background: Previously, we identified potential predictive biomarkers of C sensitivity related to EGFR signaling from archived tumor tissue from CALGB 80203. Due to the fact that blood-based markers are more convenient and can be monitored over the course of treatment, baseline plasma samples were also collected and five (EGF, HB-EGF, sEGFR, sHER2, sHER3) of the 14 markers previously analyzed in archived tumor were evaluated in plasma. Methods: CALGB 80203 was a randomized (1:1) phase II trial of 238 pts with locally advanced or metastatic CRC comparing FOLFOX or FOLFIRI (chemo) vs. chemo combined with C. Baseline EDTA plasma samples from 154 pts were analyzed for the 5 candidate markers. The levels of each analyte were correlated with the primary endpoint of OS using univariate Cox proportional hazards models. Potential predictive markers were identified using a treatment by marker interaction term in the Cox model and the markers with significant p-values are reported. Hazard ratios between treatment groups are reported for low or high marker levels dichotomized at the median. Results: Univariate analyses indicated that plasma levels of EGF and sHER3 were negative prognostic markers (p<0.05) that correlated with OS for the overall pt population. Across all pts (KRAS mutant and wild-type), sHER3 was identified as a potential predictive biomarker for C. Pts with higher sHER3 levels had significant OS benefit from C treatment (interaction p=0.03; HR=0.57, 95% CI 0.36-0.92). Low levels of EGF predicted for OS benefit from C in KRAS WT tumors (interaction p<0.01; HR=0.39, 95% CI 0.18-0.87) and lack of benefit in the KRAS mutant pts (interaction p=0.03; HR=3.03, 95% CI 1.13-8.16), but were not predictive for C across all pts combined. Conclusions: Blood-based profiling of EGFR axis members identified sHER3 and EGF as candidate predictors for benefit from C. These data are consistent with our findings using mRNA expression from archived tumor samples and suggest a role for receptor shedding in HER3 biology. If further validated, these markers may help guide the development and use of anti-EGFR therapies and combination regimens.

A phase Ib study of combined VEGFR and mTOR inhibition with vatalanib and everolimus in patients with advanced renal cell carcinoma

BACKGROUND

Vatalanib is an oral vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI), whereas everolimus inhibits mammalian target of rapamycin (mTOR). Combination therapy with VEGFR and mTOR inhibitors has not been well tolerated to date but may have efficacy in renal cell carcinoma (RCC).

PATIENTS AND METHODS

A phase Ib study of vatalanib and everolimus was performed in patients with advanced solid tumors to determine the maximum tolerated dose (MTD), safety, and tolerability of the combination. A dose-expansion cohort of 20 patients with metastatic RCC was studied to further define toxicity and preliminary efficacy in patients with RCC.

RESULTS

We evaluated 32 patients over 3 dose levels and a dose-expansion cohort. The most common toxicities of any grade were proteinuria, fatigue, hypertriglyceridemia, nausea, and vomiting. Dose-limiting toxicities (DLTs) included severe hypertension, diarrhea, neutropenia, mucositis, and fatigue. The MTD for the combination was vatalanib 1000 mg daily and everolimus 5 mg daily. In all patients, median overall survival (OS) was 16.3 months. In patients with RCC, median progression-free survival (PFS) was 5.8 months, and OS was 16.5 months. OS was significantly better in treatment-naive patients (25.1 months) compared with patients who had received previous vascular endothelial growth factor (VEGF)-targeted therapy (6.3 months). Seven of 24 (29.2%) evaluable patients demonstrated a partial response, and an additional 15 patients exhibited stable disease. Long-term tolerability (> 1 year) was demonstrated in 19% of patients.

CONCLUSION

Relevant doses of vatalanib and everolimus were achieved in combination, with expected toxicities. A substantial number of patients with RCC achieved an objective response in the treatment-naive setting, with prolonged tolerability and survival. Further comparative phase II/III studies of specifically targeted VEGF and mTOR inhibitor combinations may be warranted in patients with RCC.

Prognostic and predictive blood-based biomarkers in patients with advanced pancreatic cancer: results from CALGB80303 (Alliance)

PURPOSE

CALGB80303 was a phase III trial of 602 patients with locally advanced or metastatic pancreatic cancer comparing gemcitabine/bevacizumab versus gemcitabine/placebo. The study found no benefit in any outcome from the addition of bevacizumab to gemcitabine. Blood samples were collected and multiple angiogenic factors were evaluated and then correlated with clinical outcome in general (prognostic markers) and with benefit specifically from bevacizumab treatment (predictive markers).

EXPERIMENTAL DESIGN

Plasma samples were analyzed via a novel multiplex ELISA platform for 31 factors related to tumor growth, angiogenesis, and inflammation. Baseline values for these factors were correlated with overall survival (OS) using univariate Cox proportional hazard regression models and multivariable Cox regression models with leave-one-out cross validation. Predictive markers were identified using a treatment by marker interaction term in the Cox model.

RESULTS

Baseline plasma was available from 328 patients. Univariate prognostic markers for OS were identified including: Ang2, CRP, ICAM-1, IGFBP-1, TSP-2 (all P < 0.001). These prognostic factors were found to be highly significant, even after adjustment for known clinical factors. Additional modeling approaches yielded prognostic signatures from multivariable Cox regression. The gemcitabine/bevacizumab signature consisted of IGFBP-1, interleukin-6, PDGF-AA, PDGF-BB, TSP-2; whereas the gemcitabine/placebo signature consisted of CRP, IGFBP-1, PAI-1, PDGF-AA, P-selectin (both P < 0.0001). Finally, three potential predictive markers of bevacizumab efficacy were identified: VEGF-D (P < 0.01), SDF1 (P < 0.05), and Ang2 (P < 0.05).

CONCLUSION

This study identified strong prognostic markers for pancreatic cancer patients. Predictive marker analysis indicated that plasma levels of VEGF-D, Ang2, and SDF1 significantly predicted for benefit or lack of benefit from bevacizumab in this population.

A phase I study of ABT-510 plus bevacizumab in advanced solid tumors

Targeting multiple regulators of tumor angiogenesis have the potential to improve treatment efficacy. Bevacizumab is a monoclonal antibody directed against vascular endothelial growth factor and ABT-510 is a synthetic analog of thrombospondin, an endogenous angiogenesis inhibitor. Dual inhibition may result in additional benefit. We evaluated the safety, tolerability, and efficacy of the combination of bevacizumab plus ABT-510 in patients with refractory solid tumors. We also explored the effects of these agents on plasma-based biomarkers and wound angiogenesis. Thirty-four evaluable subjects were enrolled and received study drug. Therapy was well tolerated; minimal treatment-related grade 3/4 toxicity was observed. One patient treated at dose level 1 had a partial response and five other patients treated at the recommended phase II dose had prolonged stable disease for more than 1 year. Biomarker evaluation revealed increased levels of D-dimer, von Willebrand factor, placental growth factor, and stromal-derived factor 1 in response to treatment with the combination of bevacizumab and ABT-510. Data suggest that continued evaluation of combination antiangiogenesis therapies may be clinically useful.

Abstract 5041: The type III TGF-beta receptor promotes FGF2-mediated neuronal differentiation in neuroblastoma

Growth factors and their receptors coordinate neuronal differentiation during development, yet their roles in the pediatric tumor neuroblastoma remain unclear. Here we report that expression of type III TGF-beta receptor (TβRIII) mRNA and protein decreases with advancing stage of neuroblastoma and positively correlates with prognosis. TβRIII expression is epigenetically suppressed by MYCN oncogene amplification and TβRIII expression can be used as a prognostic marker in neuroblastoma patients with MYCN amplification. TβRIII expression in neuroblastoma cells promotes neuronal differentiation and enhances the differentiating effects of FGF2 treatment. Mechanistically, glycosaminoglycan modifications on TβRIII bind FGF2 and FGFR1 to promote neuronal differentiation via Erk MAPK and the transcription factor ID1. TβRIII-mediated differentiation suppresses tumor cell proliferation in vitro and in vivo. These studies characterize a novel co-receptor function for TβRIII in FGF2-mediated neuronal differentiation of neuroblastoma cells, while identifying potential therapeutic targets and clinical biomarkers for advanced-stage disease. More generally, our results suggest that the targeting of growth factor receptors and downstream signaling pathways may prove useful in promoting neuronal differentiation to suppress neuroblastoma tumor growth.

Citation Format: Erik H. Knelson, Angela L. Gaviglio, Alok K. Tewari, Michael B. Armstrong, Andrew B. Nixon, Mark D. Starr, Karthikeyan Mythreye, Gerard C. Blobe. The type III TGF-beta receptor promotes FGF2-mediated neuronal differentiation in neuroblastoma. [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 5041. doi:10.1158/1538-7445.AM2013-5041

Correlation of angiogenic biomarker signatures with clinical outcomes in metastatic colorectal cancer patients receiving capecitabine, oxaliplatin, and bevacizumab

A novel combination of capecitabine, oxaliplatin, and bevacizumab was evaluated in colorectal cancer patients enrolled in a phase II clinical trial. In this retrospective analysis, plasma samples from patients receiving capecitabine, oxaliplatin, and bevacizumab were analyzed to investigate biomarkers of clinical benefit. Forty-one protein biomarkers were tested in 38 patients at baseline and after two cycles of drug administration. Correlations among analytes were evaluated by Spearman analysis. Analyte levels at baseline and changes on-treatment were correlated with progression-free survival (PFS) and overall survival (OS) by univariate analysis. Multivariate analyses were determined using the Cox proportional hazard model. Time to event analyses were evaluated by Kaplan-Meier analysis and compared by log-rank test. Baseline levels of vWF and Ang-2 significantly correlated with PFS, while levels of VCAM-1, vWF, TSP-2, IL-8, MMP-2, and Ang-2 correlated with OS (P < 0.05). The fold change of IGF-1 levels from baseline to the end of cycle 2 was correlated with PFS, while fold changes of Ang-2, TSP-2, and TGF-β2 correlated with OS. A baseline signature of Ang-2, IGFBP-3, IL-6, and VCAM-1 identified a low-risk and high-risk group of patients (OS: 33.9 months vs. 18.1 months, respectively, P = 0.016). For treatment-related changes, a signature consisting of Ang-2, E-Cadherin, IL-6, MCP-1, OPN, and TGF-β1 was able to stratify patients into high- and low-risk groups (PFS: 7.7 months vs. 15.5 months, P = 0.004). Multiplex analysis of patient plasma in this trial identified several baseline- and treatment-related biomarkers associated with clinical outcome. These findings merit further exploration in larger, controlled clinical trials.

Dasatinib (BMS-35482) has synergistic activity with paclitaxel and carboplatin in ovarian cancer cells

PURPOSE

To explore the activity of dasatinib alone and in combination with paclitaxel and carboplatin in ovarian cancer cells and to determine if dasatinib activity can be predicted based on evaluation of the SRC pathway.

EXPERIMENTAL DESIGN

Microarray analysis was performed for IGROV1, OVCAR3, A2780 and SKOV3 ovarian cancer cells and the status of the genomic SRC signature pathway was determined. Cells were treated with carboplatin, paclitaxel and dasatinib individually and in combination. Pre- and post-treatment phospho-SRC (pSRC) and SRC protein expression was determined. Dose-response curves were constructed, and drug interaction was assessed by the Combination Index (CI) method.

RESULTS

SRC protein expression levels reflected the SRC pathway genomic signature in the cell lines with the lowest (SKOV3) and highest (IGROV1) pathway expression, but not in those with intermediate expression (OVCAR3, A2780). Dasatinib treatment caused loss of pSRC in all cell lines, with 50% growth inhibition for IGROV1 at 70 nM, OVCAR3 at 34 nM, A2780 at 4.1 μM and SKOV3 at 530 nM. Dasatinib combined with cytotoxics yielded a synergistic effect (CI=0.46 to 0.79) in all cell lines except SKOV3.

CONCLUSION

Dasatinib in combination with standard chemotherapeutic agents appears to interact in a synergistic manner in some ovarian cancer cell lines. Further research is needed to evaluate tumor cell characteristics which predict response to dasatinib.

Chagas' disease: risk factors for house infestation by Triatoma dimidiata, the major vector of Trypanosoma cruzi in Costa Rica

The reduction of domiciliary infestation by insect vectors, the key to controlling Chagas' disease, depends on identification of housing features associated with infestation. In this study, log-linear modeling was used to reanalyze data collected in 1964-1968 from 371 houses on characteristics potentially associated with infestation by the vector Triatoma dimidiata in a Costa Rican town with endemic Chagas' disease. A possible increased risk of infestation was observed for houses with a dirt floor (as compared with houses with another floor type) and for houses in poor sanitary condition (as compared with houses in good sanitary condition). A new risk factor for house infestation, the presence of roof tiles, was identified; the odds of infestation for houses with a tile roof were 2.4 times greater than the odds for houses with a galvanized metal roof. This significantly increased risk is probably due to the harboring of T. dimidiata in stacks of spare tiles next to house walls rather than to the tile roofs themselves.

Estrone sulfate concentrations as an indicator of fetal demise in horses

Serum and urinary estrone sulfate concentrations were determined in 7 pregnant mares before and after prostaglandin-induced abortion (n = 4) or surgical removal of the fetus (n = 3) to determine the source of estrogen during early pregnancy (gestation days [GD] 44 to 89). Estrone sulfate concentrations also were determined in serum samples (stored frozen for 2 years) from 3 mares that had been ovariectomized between GD 51 and 58. Estrone sulfate concentrations decreased in serum and urine after expulsion or removal of the fetus (urinary patterns were more definitive than were patterns for serum), whereas a transient decrease in serum estrone sulfate concentration was observed after ovariectomy. Seemingly, products of conception are the major source of estrone sulfate during early pregnancy, although there appears to be some ovarian contribution. Serum or urinary estrone sulfate measurements provide a simple and accurate test for fetal viability after GD 44 in the mare.