Hepatitis B Virus Pre-S Mutants as Biomarkers and Targets for the Development and Recurrence of Hepatocellular Carcinoma

Chronic hepatitis B virus (HBV) infection is a major risk factor for the development of hepatocellular carcinoma (HCC), the leading cause of cancer-related death worldwide. Despite progress in the prevention and therapy of HCC, high incidence and recurrence rates of HCC remain big threats, resulting in poor patient survival. Effective biomarkers and targets of HCC are therefore urgently needed for better management and to improve patient outcomes. Pre-S mutants have been well demonstrated as HBV oncoproteins that play important roles in HCC development through activation of multiple oncogenic signal pathways in hepatocytes, in vitro and in vivo. The presence of pre-S mutants in patients with chronic HBV infection and HBV-related HCC has been associated with a significantly higher risk of HCC development and recurrence after curative surgical resection, respectively. In this review, we summarize the roles of pre-S mutants as biomarkers for predicting HBV-related HCC development and recurrence, and highlight the pre-S mutants-activated oncogenic signal pathways as potential targets for preventing HBV-related HCC development.

Development of a Label-Free Electrochemical Aptasensor for the Detection of Tau381 and its Preliminary Application in AD and Non-AD Patients' Sera

The electrochemical aptamer sensor has been designed for detecting tau381, a critical biomarker of Alzheimer's disease in human serum. The aptasensor is obtained by immobilizing the aptamer on a carboxyl graphene/thionin/gold nanoparticle modified glassy-carbon electrode. As a probe and bridge molecule, thionin connected carboxyl graphene and gold nanoparticles, and gave the electrical signal. Under optimal conditions, the increment of differential pulse voltammetry signal increased linearly with the logarithm of tau381 concentration in the range from 1.0 pM to 100 pM, and limit of detection was 0.70 pM. The aptasensor reliability was evaluated by determining its selectivity, reproducibility, stability, detection limit, and recovery. Performance analysis of the tau381 aptasensor in 10 patients' serum samples showed that the aptasensor could screen patients with and without Alzheimer's disease. The proposed aptasensor has potential for use in clinically diagnosing Alzheimer's disease in the early stage.

Evaluation of Emergent Mutations in Circulating Cell-Free DNA and Clinical Outcomes in Patients with Metastatic Colorectal Cancer Treated with Panitumumab in the ASPECCT Study

PURPOSE

Mutations in EGFR pathway genes are poor prognostic indicators in patients with metastatic colorectal cancer. Plasma analysis of cell-free DNA is a minimally invasive and highly sensitive method to detect somatic mutations in tumors.

EXPERIMENTAL DESIGN

Plasma samples collected from panitumumab-treated patients in the ASPECCT study at baseline and safety follow-up (SFU) were analyzed by a next-generation sequencing-based approach for extended RAS mutant allele frequency as a continuous variable and their association with clinical outcomes and the mutational prevalence of 63 cancer-related genes. The correlation between patient outcome and baseline mutational status of EGFR pathway genes was also examined.

RESULTS

Overall, 261 patients in the panitumumab arm had evaluable plasma samples. Patients with a higher RAS mutant allele frequency at baseline had worse clinical outcomes than those with a lower frequency (P < 0.001, Cox PH model); however, RAS mutations did not necessarily preclude patients from deriving benefits. The objective response rate (complete or partial response) was 10.8% for patients with baseline RAS mutations and 21.7% for those with BRAF mutations. The 63-gene panel analysis revealed an increase in tumor mutational burden from baseline to SFU (P < 0.001, Wilcoxon signed rank test). Baseline mutations in EGFR pathway genes, when analyzed both categorically and continuously, were associated with shorter survival.

CONCLUSIONS

When mutations in EGFR pathway genes were analyzed continuously, higher mutant allele frequency correlated with poorer outcomes. However, extended RAS mutation, by itself, did not preclude clinical responses to panitumumab in a monotherapy setting.

FGF23-S129F mutant bypasses ER/Golgi to the circulation of hyperphosphatemic familial tumoral calcinosis patients

FGF23 is essential for the homeostasis of phosphate, and vitamin D. Loss-of-function mutations in this hormone cause hyperphosphatemic familial tumoral calcinosis (HFTC). Earlier reports suggested that intact FGF23 from loss of function mutants such as FGF23/S129F (iFGF23/S129F) is retained intracellularly while the carboxy-terminal fragment is secreted. We sought to investigate the fate of iFGF23/S129F mutant hormone in vivo and in vitro. Five patients clinically diagnosed with HFTC and confirmed by DNA sequencing to carry the c.386 C>T; p.S129F mutation in the homozygous state were studied. Healthy and heterozygous individuals were used as controls in the study. Using ELISA assays, we showed that iFGF23/S129F was 2-5 folds higher in patients' plasma, compared to heterozygous or healthy controls. Importantly, the mutant hormone could not be detected in the patients' sera. However, using proteinase inhibition profiling, we found that a serum metalloproteinase degraded the iFGF23/S129F explaining our failure to detect it in sera. The serum metalloproteinase degrades the WT and the mutant at different rates. Also, confocal microscopy imaging using wild-type (WT) FGF23 or FGF23/S129F mutant in transiently transfected HEK293 and HeLa cells showed weak staining of the Golgi complex with some vesicular staining resembling the ER. Additionally, FGF23 variants (FGF23/WT, FGF23/S129F, FGF23/S71G, and FGF23/R176Q) from stably transfected HEK293 cells secreted high levels into a serum-free medium that can be detected by ELISA and Western blot. Our results suggest that iFGF23/S129F mutant bypasses the ER/Golgi quality control system to the circulation of HFTC patients by an unknown pathway. Finally, we hypothesize that either the mutant hormone is unable to bind α-Klotho-FGFR1c, or it binds the dyad receptor with low affinity and, therefore, incapable of initiating maximal intracellular signaling. Our findings raise the potential use of the WT hormone in therapies of some HFTC patients.

Transgenic expression of nonclassically secreted FGF suppresses kidney repair

FGF1 is a signal peptide-less nonclassically released growth factor that is involved in angiogenesis, tissue repair, inflammation, and carcinogenesis. The effects of nonclassical FGF export in vivo are not sufficiently studied. We produced transgenic mice expressing FGF1 in endothelial cells (EC), which allowed the detection of FGF1 export to the vasculature, and studied the efficiency of postischemic kidney repair in these animals. Although FGF1 transgenic mice had a normal phenotype with unperturbed kidney structure, they showed a severely inhibited kidney repair after unilateral ischemia/reperfusion. This was manifested by a strong decrease of postischemic kidney size and weight, whereas the undamaged contralateral kidney exhibited an enhanced compensatory size increase. In addition, the postischemic kidneys of transgenic mice were characterized by hyperplasia of interstitial cells, paucity of epithelial tubular structures, increase of the areas occupied by connective tissue, and neutrophil and macrophage infiltration. The continuous treatment of transgenic mice with the cell membrane stabilizer, taurine, inhibited nonclassical FGF1 export and significantly rescued postischemic kidney repair. It was also found that similar to EC, the transgenic expression of FGF1 in monocytes and macrophages suppresses kidney repair. We suggest that nonclassical export may be used as a target for the treatment of pathologies involving signal peptide-less FGFs.

The common genetic variant of luteinizing hormone has a longer serum half-life than the wild type in heterozygous women

CONTEXT

The common genetic variant of human LH has two mutations and an extra N-linked oligosaccharide chain, a modification expected to affect the half-life in the circulation.

OBJECTIVES

Our objectives were to determine the half-lives of variant and wild-type forms of LH during GnRH receptor blockade in heterozygous women and to determine the time-related changes in isoform composition.

DESIGN AND PARTICIPANTS

Serum samples were obtained from three healthy women heterozygous for variant LH before and up to 20 h after administration of the NAL-GLU GnRH antagonist.

MAIN OUTCOME MEASURES

The half-lives were estimated by monoexponential decay. The number of sialic acid and sulfonated N-acetylgalactosamine residues per wild-type and variant LH molecule and the distribution of molecules with zero, one, two, or three sulfonated residues were measured.

RESULTS

The variant LH had a half-life that was approximately 40% longer than the corresponding forms of wild-type LH (148 vs. 108 min; P < 0.001). Variant LH had more sialic acid residues per molecule than wild type (3.6 vs. 2.4; P < 0.05), whereas the number of sulfonated residues was similar (1.0 vs. 0.98). The decline in the variant LH during GnRH receptor blockade was associated with a decrease in sulfonated and an increase in sialic acid residues similar to that for in wild-type LH. Isoforms of either variant or wild-type LH with two to three sulfonate groups per molecule had the shortest half-life.

CONCLUSION

Variant LH remains longer in circulation than wild type during GnRH receptor blockade in heterozygous women, in accord with its higher content of sialic acid.

Detection of mutant BRAF alleles in the plasma of patients with metastatic melanoma

Mutations in the BRAF oncogene at amino acid 600 have been reported in 40 to 70% of human metastatic melanoma tissues, and the critical role of BRAF in the biology of melanoma has been established. Sampling the blood compartment to detect the mutational status of a solid tumor represents a highly innovative advance in cancer medicine, and such an approach could have advantages over tissue-based techniques. We report the development of a fluorescence-based polymerase chain reaction (PCR) assay to detect mutant BRAF alleles in plasma. A mutant-specific PCR assay was optimized to specifically amplify the mutant BRAF allele without amplifying the wild-type allele. Experiments mixing DNA from a BRAF mutant melanoma cell line with wild-type human placental DNA in varying proportions were performed to determine the threshold of this assay and to compare it with routine DNA sequencing. The assay was then applied to tissue and plasma specimens from patients with metastatic melanoma. The assay detected 0.1 ng of mutant DNA mixed in 100 ng of wild-type DNA and was 500-fold more sensitive than DNA sequencing. The assay detected mutant BRAF alleles in plasma samples from 14 of 26 (54%) metastatic melanoma patients. These data demonstrate the feasibility of blood-based testing for BRAF mutations in metastatic melanoma patients.

JAK2V617F detection and dosage of serum erythropoietin: first steps of the diagnostic work-up for patients consulting for elevated hematocrit

The predictive values of common biological criteria for the diagnosis of polycythemia vera were studied in a cohort of patients with high hematocrit. We found JAK2V617F and erythropoietin assays were the most relevant first tests. Classification of patients according to their JAK2V617F status and erythropoietin levels facilitated the choice of further diagnostic investigations.

Mutant p53 protein in the serum of patients with colorectal cancer: Correlation with the level of carcinoembryonic antigen and serum epidermal growth factor receptor

INTRODUCTION

Enzyme-linked immunosorbent assay (ELISA) was used for analysis of serum mutant p53 protein, carcinoembryonic antigen (CEA), and epidermal growth factor receptor (EGFR). Serum samples were obtained from 48 patients with colorectal cancer (CRC) and a control group of twenty healthy individuals.

RESULTS

The results demonstrated a significant increase of serum mutant p53, EGFR, and CEA levels in CRC patients compared to the control group (P<0.001 for each). Mutant p53 protein was significantly different in the different CRC grades (P=0.028). p53, CEA, and EGFR can differentiate successfully between different CRC grades and normal control (P<0.001 for each). Sensitivities of p53, CEA, and EGFR were 39.6, 31, and 71%, respectively. There was no correlation between CEA, EGFR, and p53 indicating that these variables were independent. Positive status of serum CEA and (or) p53 was found in 29 out of 48 (60%) patients. Also, positive status of serum CEA and (or) EGFR was found in 39 out of 48 (81%) patients.

CONCLUSION

Thus, the simultaneous determination of p53 or EGFR combined with the CEA may increase the sensitivity to diagnose CRC patients and may aid in disease prognosis.