Molecular evolution of HIV-1 CRF01_AE Env in Thai patients

Background

The envelope glycoproteins (Env), gp120 and gp41, are the most variable proteins of human immunodeficiency virus type 1 (HIV-1), and are the major targets of humoral immune responses against HIV-1. A circulating recombinant form of HIV-1, CRF01_AE, is prevalent throughout Southeast Asia; however, only limited information regarding the immunological characteristics of CRF01_AE Env is currently available. In this study, we attempted to examine the evolutionary pattern of CRF01_AE Env under the selection pressure of host immune responses.

Methodology/Principal Findings

Peripheral blood samples were collected periodically over 3 years from 15 HIV-1-infected individuals residing in northern Thailand, and amplified env genes from the samples were subjected to computational analysis. The V5 region of gp120 showed highest variability in several samples over 3 years, whereas the V1/V2 and/or V4 regions of gp120 also showed high variability in many samples. In addition, the N-terminal part of the C3 region of gp120 showed highest amino acid diversity among the conserved regions of gp120. Chronological changes in the numbers of amino acid residues in gp120 variable regions and potential N-linked glycosylation (PNLG) sites are involved in increasing the variability of Env gp120. Furthermore, the C3 region contained several amino acid residues potentially under positive selection, and APOBEC3 family protein-mediated G to A mutations were frequently detected in such residues.

Conclusions/Significance

Several factors, including amino acid substitutions particularly in gp120 C3 and V5 regions as well as changes in the number of PNLG sites and in the length of gp120 variable regions, were revealed to be involved in the molecular evolution of CRF01_AE Env. In addition, a similar tendency was observed between CRF01_AE and subtype C Env with regard to the amino acid variation of gp120 V3 and C3 regions. These results may provide important information for understanding the immunological characteristics of CRF01_AE Env.

Sustained appearance of drug resistance-associated mutations in HIV-1 CRF01_AE protease and reverse transcriptase derived from protease inhibitor-naive Thai patients

Previous studies revealed that HIV-1 CRF01_AE viruses derived from antiretroviral drug-naïve Thai patients contained several protease (PR) inhibitor (PI) resistance-associated mutations. In this report, we examined the sustained appearance of drug resistance-associated mutations in CRF01_AE PR and reverse transcriptase (RT). Peripheral blood samples were collected every 3 months from April 2008 to April 2009 from 39 HIV-1-infected Thai patients, including 17 drug-naive and 22 RT inhibitors (RTIs)-treated individuals, and polymerase chain reaction-mediated-amplification and sequencing analysis of the viral genome encoding PR and RT were performed. We successfully analyzed the deduced amino acid sequence of CRF01_AE PR and RT derived from samples continuously collected from 15 drug-naïve and 20 RTIs-treated patients. Drug resistance-associated mutations were continuously detected in CRF01_AE PR derived from most patients. The continuous appearance of such PR mutations was observed not only in the proviral DNA genome derived from peripheral blood mononuclear cells, but also in the viral RNA genome of plasma virus. In contrast, RTI resistance-associated mutations were only sporadically detected in samples derived from drug-naive and RTIs-treated patients, except for the continuous appearance of two mutations in samples derived from two drug-naive patients. Our results demonstrate that many PI resistance-associated mutations and only a few RTI resistance-associated mutations continuously appear in CRF01_AE viruses derived from PI-naïve patients residing in northern Thailand.

The significance of HER-2/neu/c-erbB-2 gene amplification in benign and malignant breast disease

This study was carried out to investigate the amplification of HER-2/neu oncogene in 66 patients with primary breast cancer and 90 samples from benign breast disease (BBD). The amplification of HER-2/neu oncogene in the DNA of paraffin-embedded specimens was determined by differential PCR. Nineteen out of 66 (28.8%) breast cancer patients showed amplification of the gene. No gene amplification was found in benign breast disease. There was no significant correlation of HER-2/neu amplification with, age, menopausal status, the number of positive nodes, tumor size, estrogen receptor, however, amplification of HER-2/neu gene was strongly correlated with nodal status (p = 0.0049). In node positive patients, the incidence of HER-2/neu amplification was high (43%). These findings indicate that the amplification of HER-2/neu gene may be of pathogenetic significance in breast cancer and may have a poor prognosis in node positive breast cancer patients while no gene amplification in benign breast disease suggests that HER-2/neu amplification is a late molecular alteration event in the pathogenesis of breast cancer.