The tumor microenvironment (TME) evolves to support tumor progression. One marker of more aggressive malignancy is hyaluronan (HA) accumulation. Here, we characterize biological and physical changes ...associated with HA-accumulating (HA-high) tumors.
We used immunohistochemistry,
imaging of tumor pH, and microdialysis to characterize the TME of HA-high tumors, including tumor vascular structure, hypoxia, tumor perfusion by doxorubicin, pH, content of collagen. and smooth muscle actin (α-SMA). A novel method was developed to measure real-time tumor-associated soluble cytokines and growth factors. We also evaluated biopsies of murine and pancreatic cancer patients to investigate HA and collagen content, important contributors to drug resistance.
In immunodeficient and immunocompetent mice, increasing tumor HA content is accompanied by increasing collagen content, vascular collapse, hypoxia, and increased metastatic potential, as reflected by increased α-SMA.
treatment of HA-high tumors with PEGylated recombinant human hyaluronidase (PEGPH20) dramatically reversed these changes and depleted stores of VEGF-A165, suggesting that PEGPH20 may also diminish the angiogenic potential of the TME. Finally, we observed in xenografts and in pancreatic cancer patients a coordinated increase in HA and collagen tumor content.
The accumulation of HA in tumors is associated with high tIP, vascular collapse, hypoxia, and drug resistance. These findings may partially explain why more aggressive malignancy is observed in the HA-high phenotype. We have shown that degradation of HA by PEGPH20 partially reverses this phenotype and leads to depletion of tumor-associated VEGF-A165. These results encourage further clinical investigation of PEGPH20.
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Why are proteins marginally stable? Taverna, Darin M.; Goldstein, Richard A.
Proteins, structure, function, and bioinformatics,
1 January 2002, Letnik:
46, Številka:
1
Journal Article
Extensive extracellular matrix (ECM) remodeling is a hallmark of metastatic pancreatic ductal adenocarcinoma (mPDA). We investigated fragments of collagen types III (C3M, PRO-C3), VI (PRO-C6), and ...VIII (C8-C), and versican (VCANM) in plasma as biomarkers for predicting progression-free survival (PFS) and overall survival (OS) in patients with mPDA treated with pegvorhyaluronidase alfa, a biologic that degrades the ECM component hyaluronan (HA), in a randomized phase 2 study (HALO109-202).
HALO109-202 comprised a discovery cohort (Stage 1, n = 94) and a validation cohort (Stage 2, n = 95). Plasma ECM biomarkers were analyzed by ELISAs. Univariate Cox regression analysis and Kaplan-Meier plots evaluated predictive associations between biomarkers, PFS and OS in patients treated with pegvorhyaluronidase alfa plus nab-paclitaxel/gemcitabine (PAG) versus nab-paclitaxel/gemcitabine (AG) alone.
PFS was improved with PAG vs. AG in Stage 1 patients with high C3M/PRO-C3 ratio (median cut-off): median PFS (mPFS) 8.0 vs. 5.3 months, P = 0.031; HR = 0.40; 95% CI 0.17-0.92). High C3M/PRO-C3 ratio was validated in Stage 2 patients by predicting a PFS benefit of PAG vs. AG (mPFS: 8.8 vs. 3.4 months, P = 0.046; HR = 0.46; 95% CI 0.21-0.98). OS was also improved in patients with high C3M/PRO-C3 ratio treated with PAG vs. AG (mOS 13.8 vs 8.5 months, P = 0.009; HR = 0.35; 95% CI 0.16-0.77). Interestingly, high C3M/PRO-C3 ratio predicted for a PFS benefit to PAG vs. AG both in patients with HA-low tumors (HR = 0.36; 95% CI 0.17-0.79) and HA-high tumors (HR = 0.20; 95% CI 0.06-0.69).
The C3M/PRO-C3 ratio measuring type III collagen turnover in plasma has potential as a blood-based predictive biomarker in patients with mPDA and provides additional value to a HA biopsy when applied for patient selection.
NCT01839487. Registered 25 April 2016.
Subcutaneous (SC) formulations of therapeutics with recombinant human hyaluronidase PH20 (rHuPH20) are currently approved across various disease indications. The rHuPH20-mediated enzymatic ...degradation of SC hyaluronan (HA) facilitates bulk fluid flow and dispersion of co-administered therapeutics. However, current methods of quantifying dispersion in the SC space are limited. Here, a novel method is outlined to quantify and follow rapid SC volumetric dispersion of a representative therapeutic fluid in the presence of rHuPH20 using computed tomography (CT).
Ten Yucatan miniature swine were randomized to three groups. Animals received simultaneous infusions of contrast agent (CA) alone (left side of the animal) or in combination with rHuPH20 (right side) at infusion rates of 2.5, 5, or 10 mL/min. Spiral CT scans (1.5 mm thickness) were conducted before and after the infusion and at regular time intervals throughout. Scans were used to create three-dimensional (3D) reconstructions of the fluid pockets and analyze surface area, volume, and sphericity.
3D reconstruction showed increased dispersion of CA with rHuPH20 compared with CA alone, with fenestration and increased dispersion in the craniocaudal and lateromedial directions. The CA with rHuPH20 fluid pockets showed an average increase of 46% in surface area (p = 0.001), a 35% increase in volume (p = 0.001) and a 17% decrease in sphericity post-infusion compared with CA alone at 30 min post-infusion.
This exploratory study confirms the value of CT imaging as a non-invasive method of assessing real-time spatial and temporal behavior of SC-administered fluids. This technique could help to assess the dispersion pattern of novel rHuPH20 SC co-formulations.
•Computed tomography was able to quantify rapid dispersion in the subcutaneous space.•rHuPH20 increased volumetric dispersion of a contrast agent vs contrast agent alone.•Surface area of a contrast agent fluid pocket increased using rHuPH20.•Fluid pocket sphericity decreased with rHuPH20 compared to contrast agent alone.
Colorectal cancer is the second leading cause of cancer death in developed countries. Genome-wide association studies (GWAS) have successfully identified novel susceptibility loci for colorectal ...cancer. To follow up on these findings, and try to identify novel colorectal cancer susceptibility loci, we present results for GWAS of colorectal cancer (2,906 cases, 3,416 controls) that have not previously published main associations. Specifically, we calculated odds ratios and 95% confidence intervals using log-additive models for each study. In order to improve our power to detect novel colorectal cancer susceptibility loci, we performed a meta-analysis combining the results across studies. We selected the most statistically significant single nucleotide polymorphisms (SNPs) for replication using ten independent studies (8,161 cases and 9,101 controls). We again used a meta-analysis to summarize results for the replication studies alone, and for a combined analysis of GWAS and replication studies. We measured ten SNPs previously identified in colorectal cancer susceptibility loci and found eight to be associated with colorectal cancer (
p
value range 0.02 to 1.8 × 10
−8
). When we excluded studies that have previously published on these SNPs, five SNPs remained significant at
p
< 0.05 in the combined analysis. No novel susceptibility loci were significant in the replication study after adjustment for multiple testing, and none reached genome-wide significance from a combined analysis of GWAS and replication. We observed marginally significant evidence for a second independent SNP in the
BMP2
region at chromosomal location 20p12 (rs4813802; replication
p
value 0.03; combined
p
value 7.3 × 10
−5
). In a region on 5p33.15, which includes the coding regions of the
TERT
-
CLPTM1L
genes and has been identified in GWAS to be associated with susceptibility to at least seven other cancers, we observed a marginally significant association with rs2853668 (replication
p
value 0.03; combined
p
value 1.9 × 10
−4
). Our study suggests a complex nature of the contribution of common genetic variants to risk for colorectal cancer.
There have been repeated observations that proteins are surprisingly robust to site mutations, enduring significant numbers of substitutions with little change in structure, stability, or function. ...These results are almost paradoxical in light of what is known about random heteropolymers and the sensitivity of their properties to seemingly trivial mutations. To address this discrepancy, the preservation of biological protein properties in the presence of mutation has been interpreted as indicating the independence of selective pressure on such properties. Such results also lead to the prediction that
de novo protein design should be relatively easy, in contrast to what is observed. Here, we use a computational model with lattice proteins to demonstrate how this robustness can result from population dynamics during the evolutionary process. As a result, sequence plasticity may be a characteristic of evolutionarily derived proteins and not necessarily a property of designed proteins. This suggests that this robustness must be re-interpreted in evolutionary terms, and has consequences for our understanding of both
in vivo and
in vitro protein evolution.
Abstract only
404
Background: Hyaluronan (HA) can be a constituent of the tumor microenvironment (TME). Accumulation of HA in the TME may result in elevated interstitial pressure, vascular ...compression, hypoxia, and reduced drug delivery and immune cell access. Pegvorhyaluronidase alfa (PEGPH20; PVHA) enzymatically degrades HA, potentially increasing access and antitumor efficacy of cytotoxic and immuno-therapies. Liquid biopsies may provide a non-invasive approach to predict therapeutic efficacy of PVHA. Methods: Total plasma HA was analyzed as a pharmacodynamic biomarker for PVHA activity in HALO 109-202 (NCT01839487), a Phase 2, open-label, two-stage randomized study of PVHA + nab-paclitaxel + gemcitabine (PAG) vs AG only, in previously untreated patients with Stage IV metastatic PDAC. HA was measured with a liquid chromatography-tandem mass spectrometry (LC-MS/MS) disaccharide assay using baseline plasma samples from Stage 1 (n = 132) and Stage 2 (n = 128) of the study. Results: Lower baseline plasma HA values were significantly correlated with survival outcomes, predicting progression-free survival (PFS) benefit in PVHA-treated patients in Stages 1 and 2, and overall survival (OS) benefit in PVHA-treated patients in Stage 2 (Table). Conclusions: These results support further exploration of a liquid biopsy-based companion diagnostic (CDx) for predicting the therapeutic efficacy of PVHA. Table: see text
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