A mouse model of vitiligo induced by monobenzone

The paucity of vitiligo animal models limits the understanding of vitiligo pathogenesis and the development of therapies for the skin disorder. In this study, we developed a new mouse model of vitiligo by topically applying the skin-depigmenting agent monobenzone on mice. We demonstrated that monobenzone-induced skin depigmentation on the non-exposed sites and that the severity of lesions depended on drug dosage. The result of the histological examination of the depigmented skin indicated loss of epidermal melanocytes and perilesional accumulation of CD8⁺ T cells. Furthermore, the monobenzone-induced depigmentation of the Rag1 gene knockout did not appear on the non-exposed sites, supporting the involvement of infiltrating CD8⁺ T cells in melanocyte destruction. Resemblance in histological characteristics and pathogenesis between monobenzone-induced depigmentation and active human vitiligo suggests good potential of our mouse model for use in vitiligo research.

Meta-analysis of associations between the TP53 Arg72Pro polymorphism with risk of head and neck carcinomas based on case-control studies

Genetic factors have been shown to play a role in the development of head and neck cancers (HNCs). However, studies investigating the association between the TP53 Arg72Pro polymorphism and HNCs susceptibility have yielded conflicting results. Hence, we performed a meta-analysis of all eligible studies (up to January 1, 2012) to derive a more precise estimation of this association in order to increase understanding of the possible risk factors of HNCs. Twenty-seven case-control studies involving 3966 cases and 4387 controls were included in our analysis. Overall, no evidence of association was observed between the TP53 Arg72Pro single nucleotide polymorphism (SNP) and the risk of HNCs in any genetic model (Arg/Arg vs Pro/Pro: odds ratio (OR) = 0.83, 95% confidence interval (CI): 0.65-1.06; Arg/Pro vs Pro/Pro: OR = 0.88, 95%CI= 0.70-1.10; Arg/Arg+Arg/Pro vs Pro/Pro: OR = 0.87, 95%CI= 0.70-1.09; Arg/Arg vs Arg/Pro+Pro/Pro: OR = 0.95, 95%CI= 0.82-1.11). Nevertheless, the TP53 Arg72Pro polymorphism shows diverse effects across different subtypes of HNCs. For example, there was a lack of association of this polymorphism with oral cavity cancer, whereas a significant association with nasopharyngeal cancer was observed. Results of this meta-analysis suggest that the TP53 Arg72Pro polymorphism might have different effects on the risk of various subtypes of HNCs.

Role of in vivo reflectance confocal microscopy in determining stability in vitiligo: a preliminary study

BACKGROUND

Vitiligo is an acquired pigmentary disorder. In vivo reflectance confocal microscopy (RCM) reproducible imaging technique has already been reported to be useful in the diagnosis of other skin diseases.

OBJECTIVE

To define RCM features of vitiligo on different clinical stages.

MATERIALS AND METHODS

A total of 125 patients with a clinical diagnosis of vitiligo were included in this study. After informed consent, lesional skins of those vitiligo patients were characterized by using RCM. Five patients with inflammatory cell infiltration observed at the edge of skin lesions and another 5 patients without inflammatory cell infiltration were selected. Biopsies were performed at same sites of the RCM examination areas for histological and immune-histological analysis.

RESULTS

In the active stage of vitiligo, the RCM examination revealed that the bright dermal papillary rings presented at the dermoepidermal junction level in normal skin lost their integrity or totally disappeared, border between vitiligo lesion and normal skin became unclear, and highly refractile cells that referred to infiltrated inflammatory cells could be seen within the papillary dermis at the edge of the lesions. In the stable stage of vitiligo, the RCM showed a complete loss of melanin in lesional skin and a clear border between lesional and normal skin.

CONCLUSION

A simple clinical examination with RCM may reliably and efficiently allow evaluation of the stability status of vitiligo lesions.

Dermal mesenchymal stem cells (DMSCs) inhibit skin-homing CD8+ T cell activity, a determining factor of vitiligo patients' autologous melanocytes transplantation efficiency

We here investigated the efficiency of autologous melanocyte transplantation of 23 vitiligo patients by focusing on perilesional skin homing CD8+ T lymphocytes, and studied the potential effect of dermal mesenchymal stem cells (DMSCs) on CD8+ T cell activities in vitro. Out of 23 patients with the autologous melanocyte transplantation, 12 patients (52.17%) had an excellent re-pigmentation, 6 patients (26.09%) had a good re-pigmentation, 5 patients (21.74%) had a fair or poor re-pigmentation. CD8+ T cells infiltrating was observed in the perilesional vitiligo area of all patients. Importantly, the efficiency of the transplantation was closely associated with skin-homing CD8+ T cell activities. The patients with high number of perilesional CD8+ T cells or high level of cytokines/chemokines were associated with poor re-pigmentation efficiency. For in-vitro experiments, we successfully isolated and characterized human DMSCs and skin-homing CD8+ T cells. We established DMSCs and CD8+ T cell co-culture system, where DMSCs possessed significant inhibitory effects against skin homing CD8+ T lymphocytes. DMSCs inhibited CD8+ T cells proliferation, induced them apoptosis and regulated their cytokines/chemokines production. Our results suggest that vitiligo patients’ autologous melanocytes transplantation efficiency might be predicted by perilesional skin-homing CD8+ T cell activities, and DMSCs might be used as auxiliary agent to improve transplantation efficacy.

Clinical controlled comparison between lobectomy and segmental resection for patients over 70 years of age with clinical stage I non-small cell lung cancer

AIMS

The standard surgical procedure for elderly (≥ 70 years) patients with clinical stage I non-small cell lung cancer (NSCLC) was investigated.

METHODS

A non-randomized prospective controlled study was conducted to compare lobectomy with segmental resection for the treatment of elderly clinical stage I lung cancer patients under different pulmonary function. Perioperative indicators including time and volume of thoracic drainage, incidence of postoperative complications, locoregional recurrence rates, and 1, 3, and 5-year survival rates were analyzed.

RESULTS

A total of 184 patients were included in the study. Patients were classified into two groups according to pulmonary function: group 1 included 64 patients who had poor pulmonary function, with a forced expiratory volume in 1 s (FEV(1)) of less than 1.5 L, whereas group 2 consisted of 120 patients with an FEV(1) ≥ 1.5 L. The patients in group 1 had a longer postoperative mechanical ventilation time and a higher incidence rate of respiratory associated complications than those in group 2 (21.9 vs. 8.35%, p = 0.009). The local recurrence and long-term survival rates were not significantly different between lobectomy and segmental resection. Among the patients who underwent segmental resection, those who had regional lymph node dissection showed a higher 3-year and 5-year survival rate than those undergoing selected lymph node resection (77.8 vs. 51.7%, p = 0.042; 55.6 vs. 27.6%, p = 0.034), but this was not significant in lobectomy.

CONCLUSIONS

Segmental resection combined with regional lymph node resection could be the best choice for elderly clinical stage I NSCLC patients with FEV(1) < 1.5 L.

Dynamic tyrosine phosphorylation modulates cycling of the HSP90-P50(CDC37)-AHA1 chaperone machine

Many critical protein kinases rely on the Hsp90 chaperone machinery for stability and function. After initially forming a ternary complex with kinase client and the cochaperone p50(Cdc37), Hsp90 proceeds through a cycle of conformational changes facilitated by ATP binding and hydrolysis. Progression through the chaperone cycle requires release of p50(Cdc37) and recruitment of the ATPase activating cochaperone AHA1, but the molecular regulation of this complex process at the cellular level is poorly understood. We demonstrate that a series of tyrosine phosphorylation events, involving both p50(Cdc37) and Hsp90, are minimally sufficient to provide directionality to the chaperone cycle. p50(Cdc37) phosphorylation on Y4 and Y298 disrupts client-p50(Cdc37) association, while Hsp90 phosphorylation on Y197 dissociates p50(Cdc37) from Hsp90. Hsp90 phosphorylation on Y313 promotes recruitment of AHA1, which stimulates Hsp90 ATPase activity, furthering the chaperoning process. Finally, at completion of the chaperone cycle, Hsp90 Y627 phosphorylation induces dissociation of the client and remaining cochaperones.

Abstract B7: Use of ponatinib to restrict growth of non-small cell lung cancer (NSCLC) cells overexpressing FGFR1

For advanced stage NSCLC, targeted molecular therapy based on an understanding of the oncogenic driver mutations is emerging as the new front line care replacing chemotherapy where the oncogenic driver mutation is clearly defined e.g EGFR mutation or EML4-ALK translocation. However, the proportion of patients that fall into this category is small and are mostly non-smokers with adeno histology. Identifying new oncogenic drivers in NSCLC is therefore paramount.

In our initial Oncomine database search, we found that FGFRs are overexpressed in various NSCLC tissue specimens. Quantitative real time PCR and Western blot analysis subsequently confirmed overexpression of FGFR1 in about one fourth of NSCLC cell lines analyzed. Among these, H520, H1299 and A549 had significantly higher levels of FGFR1 expression compared to H3122 which carries an EML4-ALK fusion protein. Real time PCR also demonstrated FGFR1 overexpression compared to normal human bronchial epithelial cells transformed by Herpes Papillary Virus E6/E7 (HBE4). Furthermore, as a sign of epithelial to mesenchymal transition, these cells switched from expressing the FGFR1 3b to the 3c form. In a colonogenic assay the growth of cells carrying FGFR1 overexpression/activation is markedly suppressed by ponatinib, a pan FGFR inhibitor as expected. Similarly, ponatinib treatment of NSCLC cell lines using 1 μM concentrations effectively suppressed the phosphorylation level of FGFR1 and its known down-stream targets including pSrc and pPLCγ without significant impact on the total protein expression. Treatment of these cells harboring FGFR1 activation with ponatinib arrests cells at the G1 phase as shown in the flow cytometry analysis. To determine whether the observed effects are specifically due to the suppression of FGFR1 by ponatinib, an shRNA knock down of FGFR1 was performed. Consistently, shFGFR1 significantly inhibited the growth of H520 and H1299 cells, whereas knock-down did not significantly affect the growth of H3122. Similar to ponatinib treatment, shFGFR1 caused more cells to arrest in G1 phase. In a MTT assay, ponatinib synergistically induced growth suppression/killing of H520 cells with cisplatin and paclitaxel. We are currently determining whether ponatinib is effective in inhibiting NSCLC cells derived directly from freshly resected lung cancer specimens.

In conclusion, the FGFR1 pathway is constitutively active in a proportion of NSCLC cell lines and ponatinib is a potent inhibitor of constitutive FGFR1 activation. Ponatinib is potentially useful as a molecularly targeted agent against this portion of NSCLC when used alone or in combination with traditional chemotherapy regimens.

Electrochemical isothermal-capacitance-transient spectroscopy: a new depth profiling method of deep levels

The authors report on a new depth profiling method of deep levels, which we call electrochemical isothermal-capacitance-transient spectroscopy (EICTS). This is combined with electrochemical capacitance-voltage using the Schottky barrier of etchable electrolyte and isothermal-capacitance-transient spectroscopy using the capacitance-transient profile at a fixed temperature. We proved its validity by applying to the ZnSe:N epitaxial film of thickness of more than 1000 nm and comparing the characteristics of an obtained deep level with the results measured by conventional deep-level detection techniques. It is expected that EICTS is very effective to assess the deep levels of wide-bandgap semiconductors that suffer from various point defects and their complexes.

The human LIS1 is downregulated in hepatocellular carcinoma and plays a tumor suppressor function

The human lissencephaly-1 gene (LIS1) is a disease gene responsible for Miller-Dieker lissencephaly syndrome (MDL). LIS1 gene is located in the region of chromosome 17p13.3 that is frequency deleted in MDL patients and in human liver cancer cells. However, the expression and significance of LIS1 in liver cancer remain unknown. Here, we investigated the expression of LIS1 in hepatocellular carcinoma (HCC) tissues by real-time PCR, Western blot, and immunohistochemistry. The results indicated that the mRNA and protein levels of LIS1 were downregulated in about 70% of HCC tissues, and this downregulation was significantly associated with tumor progression. Functional studies showed that the reduction of LIS1 expression in the normal human liver cell line QSG7701 or the mouse fibroblast cell line NIH3T3 by shRNA resulted in colony formation in soft agar and xenograft tumor formation in nude mice, demonstrating that a decrease in the LIS1 level can promote the oncogenic transformation of cells. We also observed that the phenotypes of LIS1-knockdown cells displayed various defective mitotic structures, suggesting that the mechanism by which reduced LIS1 levels results in tumorigenesis is associated with its role in mitosis. Furthermore, we demonstrated that ectopic expression of LIS1 could significantly inhibit HCC cell proliferation and colony formation. Our results suggest that LIS1 plays a potential tumor suppressor role in the development and progression of HCC.

Cancer cells harboring MET gene amplification activate alternative signaling pathways to escape MET inhibition but remain sensitive to Hsp90 inhibitors

Hepatocyte growth factor/scatter factor (HGF/SF) receptor c-Met is implicated in growth, invasion and metastasis of many tumors. Tumor cells harboring MET gene amplification are initially sensitive to c-Met tyrosine kinase inhibitors (TKI), but escape from long-term treatment has not been investigated. C-Met is a client of heat shock protein 90 (Hsp90) and is destabilized by Hsp90 inhibitors, suggesting that these drugs may inhibit tumors driven by MET amplification, although tumor escape under these conditions also has not been explored. Here, we evaluated the initial inhibitory effects of, and the likelihood of escape from, the Hsp90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) and the c-Met TKI SU11274, using two cell lines harboring MET gene amplification. 17-AAG inhibited cell growth in both cell lines and induced substantial apoptosis, whereas SU11274 was only growth inhibitory in one cell line. In both cell lines, c-Met-dependent Akt, Erk and/or STAT3 signaling, as well as activation of the EGFR family, resumed shortly after treatment with c-Met TKI despite sustained c-Met inhibition. PKC delta upregulation may participate in reactivation of c-Met downstream signaling in both cell lines. In contrast to c-Met TKI, 17-AAG destabilized c-Met protein and durably blocked reactivation of downstream signaling pathways and EGFR family members. Our data demonstrate that downstream signaling in tumor cells overexpressing c-Met is not stably suppressed by c-Met TKI, even though c-Met remains fully inhibited. In contrast, Hsp90 inhibitors provide long-lasting suppression of c-Met-dependent signaling, and these drugs should be further evaluated in tumors driven by MET gene amplification.

Transferrin and haemoglobin polymorphism in domesticated goats in the USA

The distribution of transferrin (Tf) and haemoglobin (Hb) polymorphisms in five goat breeds in the USA is reported. Two Tf types, A and B, were identified. A significant difference in frequency (P less than 0.05) was observed only between the Spanish and Alpine goats. Haemoglobin beta-globin variants, Hb beta A, Hb beta D and Hb beta E were observed with isoelectric focusing at pH ranges 5-8 and 6.7-7.7. Hb beta D was not found in the Alpine and Angora breeds. Haemoglobin allelic frequencies varied widely and differed significantly (P less than 0.05) among breeds.

Construction and identification of an antisense glucose transporter-1 plasmid

Our aim was to construct a pcDNA3.1(+) eucaryotic expression system vector containing the antisense glucose transporter-1 (Glut-1) gene. Total RNA was isolated from human Hep-2 laryngeal carcinoma cells, and the Glut-1 and antisense Glut-1 sequences were amplified by polymerase chain reaction. Expression plasmids containing the sense and antisense cDNA were constructed using the pcDNA3.1(+) vector. The resulting sense and antisense vectors, pcDNA3.1(+)-Glut-1 and pcDNA3.1(+)-antiGlut-1, respectively, were examined by restriction analysis and DNA sequencing. The pcDNA3.1(+)-antiGlut-1 was subsequently transfected into Hep-2 cells. AntiGlut-1 mRNA expression was detected, indicating the successful construction of an antisense Glut-1 plasmid capable of transfecting Hep-2 laryngeal carcinoma cells. These data provide a firm basis for additional studies using the plasmid pcDNA3.1(+)-antiGlut-1 to determine its therapeutic potential for the treatment of laryngeal carcinoma.

Targeting Hsp90 prevents escape of breast cancer cells from tyrosine kinase inhibition

Recent studies have identified development of resistance to tyrosine kinase inhibition (TKI) as a significant roadblock to effective treatment. One mechanism of resistance recently appreciated involves 'oncogene switching', or the re-activation of signaling pathways by one or more redundant upstream activators. In breast cancer models, ErbB TKIs such as gefitinib have been shown to lose the ability to modulate ErbB-driven signaling pathways over time, even though ErbB inhibition is maintained. Although incomplete ErbB inhibition has been proposed to underlie this phenomenon, our findings suggest that oncogene switching can also re-activate downstream signaling pathways in breast cancer cells, even when ErbB inhibition is complete. We find that ErbB TKI-induced Src activation mediates downstream signaling rebound in SKBR3 cells, and we show that combination of Src and ErbB inhibitors is more effective and longlasting than is either TKI alone. Finally, the Hsp90 inhibitor 17-AAG, by simultaneously and durably inhibiting multiple signaling activators including ErbB and Src kinases, does not permit oncogene switching and results in a more prolonged and robust inhibition of downstream signaling pathways in breast cancer cells than do individual TKIs. These data support the continued clinical evaluation of Hsp90 inhibitors in breast cancer.

Primary malignant myoepithelioma of the left maxillary sinus: a case report

We describe the case of a 41-year-old woman who presented with a malignant myoepithelioma (MME) in her left maxillary sinus. Exploratory biopsy of the left maxillary sinus was performed and pathological examination demonstrated that the tumour was positive for calponin and cytokeratin 14, which are indicative of MME. Lateral rhinotomy and left total maxillectomy were undertaken and the patient received radiotherapy and chemotherapy post-surgery. Primary recurrence and metastasis to the left angle of the mandible occurred 9 months after the surgery. The patient died of cachexia 13 months after the surgery.

A rare case of large, unusual, and mutilating verruca vulgaris with cutaneous horns treated with plastic surgery

Cutaneous horn is a morphologic designation for a protuberant mass of keratin produced by unusual cohesiveness of keratinized material. We report a rare case of large, unusual, and mutilating verruca vulgaris with cutaneous horns in a 39-year-old male peasant. To our knowledge, this is the first case of the underlying phalangeal bones being largely demolished, resulting in serious mutilation. The patient was successfully treated with plastic surgery. Of note in this case is the bone absorption of the terminal phalanges and loss of hand function.

Regulation of RUNX1/AML1 during the G2/M transition

The acute myeloid leukemia 1 (AML1, RUNX1) transcription factor is a key regulator of hematopoietic differentiation both in embryonic stem cells and mature hematopoietic progenitors. The RUNX1 protein is thought to play a role in the control of progression through the cell cycle. We have shown that post-transcriptional regulation of RUNX1 activity occurs, in part, through phosphorylation. To investigate whether transit through the cell cycle is associated with changes in the phosphorylation of RUNX1, we have derived phospho-specific antibodies against three of the five major phosphorylation sites in the transcriptional activation domain of RUNX1, S276, S303 and S462. Using these antibodies we demonstrate that treatment of Jurkat T-cells with nocodazole, a G2/M blocking compound, causes an increase in phosphorylation of these three amino acids. By elutriating the Jurkat cells, we are able to demonstrate that these amino acids are normally phosphorylated at the G2/M phase of the cell cycle. Using in vivo inhibitors and in vitro assays this phosphorylation appears to be dependent on Cdk1. We find that RUNX1 degradation occurs at the G2/M-G1 transition and is regulated by both Cdc20 and phosphoryation, suggesting that the anaphase promoting complex plays a role in modifying the level of this protein. Regulation of the extent of phosphorylation of RUNX1 may play a role in controlling the degradation of the protein, implying that additional E3 ligases may also be involved.

Whole genome expression profiling of hepatitis B virus-transfected cell line reveals the potential targets of anti-HBV drugs

Hepatitis B virus (HBV) infection is a major health concern world wide, and few effective treatments have been developed. It has recently been reported that inhibiting host-cell proteins can prevent viral infection. The human genome may contain more genes required for HBV infection and replication than the viral genome. A systematic approach to find these potential antiviral targets is by host gene expression analysis using DNA microarrays. The aim of this study was to identify and validate novel cellular anti-HBV targets. The Human Whole Genome Bioarray was used to analyze differentially expressed genes in HepG2.2.15 cells and HepG2 cells. Altered gene expression in HepG2.2.15 cells was studied following treatment with the anti-HBV drug, lamivudine. Genes that were differentially expressed during HBV infection and reversed with anti-HBV drugs were validated by semiquantitative reverse transcription-PCR. Bioinformatics analysis revealed ABHD2, EREG, ACVR2B, CDC34, KHDRBS3 and RORA as potential cellular anti-HBV targets. Antisense oligodeoxynucleotides were used to test the antiviral activity of these potential targets. Results strongly suggested that inhibition of ABHD2 or EREG significantly blocked HBV propagation in HepG2.2.15 cells. This study demonstrates that ABHD2 and EREG are essential for HBV propagation and provides strong evidence that these proteins could be used as potential targets for anti-HBV drugs.

Telomerase antisense inhibition for the proliferation of endometrial cancer in vitro and in vivo

The objective of this study was to investigate the antitumor effect of antisense telomerase oligodeoxynucleotides to endometrial cancer cells in vitro and in vivo. Antisense oligodeoxynucleotides (ODNs) against the human telomerase transcripatse (hTERT) synthesized to serve as telomerase inhibitors. Reverse transcription–polymerase chain reaction and 3-[4,5-dimethylthiazol-2yl]-2,5-diphenyltetrazolium bromide (MTT) assay were used to test the expression of hTERT messengerRNA (mRNA) and inhibition of cell proliferation in vitro. In vivo, antitumor effects of ODNs or combined with cisplatin were evaluated in endometrial cancer xenograft. Telomerase activity was tested by telomeric repeat amplification protocol. Antisense ODNs could inhibit proliferation of human endometrial cancer cells (HEC-1-A) in vitro, and downregulate the expression hTRET mRNA in a dose- and period-dependent manner. The tumor growth inhibitory rate of low- and high-dose ODNs were 34.20% and 89.21%, and combined group was 75.30%. Telomerase activity was downregulated to 87.32% compared to the control in the ODNs-treated xenograft tumors. Antisense oligonucleotides of hTERT effectively inhibit the growth of endometrial cancer cell line. Telomerase inhibitor might be a new strategy for chemotherapy or chemoprevention in endometrial cancer.

Antisense oligonucleotides targeted against asialoglycoprotein receptor 1 block human hepatitis B virus replication

Chronic hepatitis B virus (HBV) infection is a major worldwide public health problem. Better therapeutics and treatment strategies are urgently needed because of ineffective clinical treatment. Our previous study showed that asialoglycoprotein receptor 1 (ASGPR1) was upregulated by HBV but downregulated by lamivudine in HepG2.2.15 cells. It has also been reported that ASGPR is a candidate receptor for HBV attachment to hepatocytes. Therefore, as a major subunit of ASGPR, ASGPR1, might be a potential target for anti-HBV drugs. To validate this hypothesis, antisense oligonucleiotides (ASODNs) were used to downregulate ASGPR1 level in HepG2.2.15 cells. By using the MFOLD web server and BLAST searches, five ASODNs theoretically targeting ASGPR1 were selected. After 72 h post-transfection, HBV-DNA level in cell medium were examined by real-time polymerase chain reaction (PCR). Hepatitis B surface antigen (HBsAg) and Hepatitis B e antigen (HBeAg) were detected using enzyme-linked immunosorbent assay (ELISA). ASGPR1 mRNA and protein level were measured by semi-quantitative reverse transcriptase (RT)-PCR and Western blot analysis respectively. The results showed that ASODN2 significantly downregulated ASGPR1 level. It also reduced HBV-DNA, HBsAg and HBeAg level in cell medium as observed with lamivudine. In contrast, the sense sequence and scrambled sequence of ASODN2 had no effect on ASGPR1 and HBV markers in HepG2.2.15 cells. This indicated that ASODN2 could specifically reduce HBV replication in vitro. Additionally, cell proliferation and apoptosis assay suggested that downregulation of ASGPR1 did not affect cell viability. We, therefore, proposed that ASODNs targeted against ASGPR1 could block HBV replication without the influence of other changes, and ASGPR1 could be targeted for anti-HBV drug development.

Differentially expressed cellular genes following HBV: potential targets of anti-HBV drugs?

The aim of the study was to screen for cellular genes that are differentially expressed following hepatitis B virus (HBV) infection, in an attempt to identify potential targets of anti-HBV drugs. An oligonucleotide microarray containing 231 virus-infection-associated genes was prepared. Differential gene expression in HepG2.2.15 cells compared to control with HepG2 cells was analysed by this in-house microarray. The change in gene expression in HepG2.2.15 cells treated by lamivudine on days 4 and 8 after exposure was also studied. Semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) was used to comfirm the differentially expressed genes induced by HBV and lamivudine. There were 31 upregulated and four downregulated genes in HepG2.2.15 cells compared with the HepG2 control cells. Eleven genes were consistently altered by lamivudine at both time points. Of the 31 genes that were upregulated in HepG2.2.15 cells, there were seven genes which were downregulated by lamivudine. Of the four downregulated genes, there was one gene which was upregulated by lamivudine. Of the differentially expressed genes induced by HBV and lamivudine, the expression of five genes was confirmed by semi-quantitative RT-PCR. These results shed new light on the effects of HBV and lamivudine on cellular gene expression. Differentially expressed genes induced by HBV and lamivudine could potentially become new anti-HBV drug targets in novel therapies.

Oligonucleotide microarray for HLA-DRB1 genotyping: preparation and clinical evaluation

In this study, HLA-DRB1 gene was genotyped by using the microarray technique. Oligonucleotide probes were designed based on partial sequences of various genotypes of HLA-DRB1, and were fixed on a silylated slide to form a microarray. The second exon of HLA-DRB1 gene in the extracted genomic DNA samples was amplified and labelled by means of polymerase chain reaction (PCR); then it was hybridized to the microarray. The microarray was scanned, and the result was analysed in order to determine the genotypes of HLA-DRB1 of the tested sample. A total of 1574 of 1592 clinical samples had accordant results of genotypes in either microarray assay or PCR-SSP assay; 8 of 10 samples that had inconsistent results of genotypes were proved to be microarray-assay reliable by confirmation of DNA sequencing. It is concluded that microarray is an alternative reliable method for HLA-DRB1 genotyping.

HBx protein of hepatitis B virus (HBV) can form complex with mitochondrial HSP60 and HSP70

HBx, a transcriptional transactivating protein of hepatitis B virus (HBV), is required for viral infection and has been implicated in virus-mediated liver oncogenesis. However, the molecular mechanism for its influence on cell remains largely unknown. It was proved that HBx need the help of host cell proteins to exert its function by binding to them. During purifying of GSTX (fusion protein of GST and HBx) expressed in E. coli, we found that it can bind specifically with GrpE (HSP60) and DnaK (HSP70) of E. coli while GST cannot. Using GST pull-down, two-dimensional gel electrophoresis and mass spectrum, we found that GSTX can also bind to human mitochondrial HSP60 and HSP70, which are homologues of GrpE and DnaK. These interactions between HBx and mitochondrial HSP60 and HSP70 are supported by the result of co-immunoprecipitation experiment. It means that HBx can form complex with E. coli and human HSP60 and HSP70. The implication of HBx, HSP60 and HSP70 complex in molecular mechanism of virus infection is discussed.

Quantification of the relative levels of wild-type and lamivudine-resistant mutant virus in serum of HBV-infected patients using microarray

During the course of lamivudine administration in hepatitis B virus (HBV)-infected patients, a dynamic development of the viral population in serum is observed. Total HBV level is initially reduced, then lamivudine-resistant mutants appear, and finally, the viral level is increased. All methods of mutant detection so far described can only identify mutants in the serum, and cannot determine the proportion of those mutants. In this paper, we report the development of a novel technique that can quantify the relative proportion of mutants in serum utilizing gene microarray technology. Based on the nucleotide sequence at the loci of the mutations in lamivudine-resistant HBV mutants, 28 probes were designed and dotted on glass film to prepare the oligonucleotide microarray. Ten standard curves were established by employing 15 reference plasmids as templates. Ten standard math functions were simulated, which allowed quantification of the proportion of mutants in the sample by measuring the value of fluorescent intensity on the microarray. By utilizing the standard math function, the relative proportion of two different mutation sequences in the mixed template could be detected with an error <10%. The HBV-lamivudine oligonucleotide microarray is reliable to quantify the relative proportion of wild-type HBV vs HBV mutants in patient's sera.

Cloning and characterization of the promoter region of human LPTS/PinX1 gene

The gene for LPTS/PinX1 encodes a potent telomerase inhibitor and suppresses tumor cell growth. In order to investigate the transcriptional regulation of this gene, we isolated its 5'-flanking region from the human genomic BAC clone and identified a major transcriptional initiation site. The sequence of the 5'-flanking region is GC-rich, lacks canonical TATA box, but contains potential binding sites for a variety of transcription factors. The deletion analysis indicated that the proximal 100 bp (from nt -66 to +34) is essential for minimal promoter activity and the regions of promoter from nt -1272 to -573 and nt -330 to -66 are required for maximal expression of the LPTS/PinX1 gene. Four DNase I hypersensitive sites (DHS1-4) mapping to the regions of transcription initiation and promoter in LPTS/Pinx1 gene were also revealed.