Xueyuan Xiao

Reduced transthyretin expression in sera of lung cancer

Lung cancer is a leading cause of cancer death worldwide, and very few specific biomarkers can be used in its clinical diagnosis. Using surface‐enhanced laser desorption–ionization time‐of‐flight mass spectrometry (MS) to find novel serum biomarkers for lung cancer, we analyzed 227 serum samples, including 146 lung cancers, 41 benign lung diseases and 40 normal individuals. Three peaks, at 13.78, 13.90 and 14.07 k m/z, were significantly lower in lung cancer sera compared with sera from normal individuals (P < 0.001), whereas these peaks were higher than those in the sera of benign lung diseases (P < 0.001). The peaks were identified as native transthyretin (TTR) and its two variants by one‐dimensional polyacrylamide gel electrophoresis, ESI‐MS/MS, immunoprecipitation and western blot analysis. An enzyme‐linked immunosorbent assay indicated that TTR levels were consistent with surface‐enhanced laser desorption–ionization analysis in all groups tested. It gave 78.5% sensitivity and 77.5% specificity for lung cancer versus normal at the cut‐off point 115 µg/mL, and 66.7% sensitivity and 64.4% specificity for lung cancer versus benign lung diseases at the cut‐off point 88.5 µg/mL. Therefore, TTR may be useful as a biomarker to improve the diagnosis of lung cancer. (Cancer Sci 2007; 98: 1617–1624)

Serum levels of variants of transthyretin down‐regulation in cholangiocarcinoma

Cholangiocarcinoma (CC) is devastating neoplasm and very few specific biomarkers could be used in clinical diagnosis. A study was taken to find novel serum biomarkers for CC.

14-kDa phosphohistidine phosphatase and its role in human lung cancer cell migration and invasion

14-kDa phosphohistidine phosphatase (PHP14) was the first protein histidine phosphatase to be discovered, but its biological function remains unclear. In our previous study, we found that it was associated with tumor invasion. Here, we investigated its role in lung cancer cell migration and invasion. Knockdown of PHP14 expression in highly metastatic lung cancer CL1-5 cells inhibited migration and invasion in vitro, but did not alter cell proliferation rates. Overexpression of PHP14 in NCI H1299 cells promoted migration and invasion in vitro, but again did not alter cell proliferation. To evaluate the metastatic properties of PHP14 in vivo, an experimental metastasis assay was performed. Experimental metastasis in vivo was extensively inhibited by PHP14 knockdown. To further examine the mechanism underlying the involvement of PHP14 in cell migration, invasion, and metastasis, a comparative proteomics analysis was performed. The differential protein expression profiles revealed that PHP14 was probably involved in cytoskeletal reorganization; this was further supported by actin filament (F-actin) staining. These results demonstrate for the first time that PHP14 may be functionally important in lung cancer cell migration and the invasion of lung cancer cells, mediated partly through modulation of actin cytoskeleton rearrangement.

Selective expression of S100A11 in lung cancer and its role in regulating proliferation of adenocarcinomas cells

S100A11, one secreted protein, is overexpressed in certain cancers. We investigated S100A11 expression in various subtypes of lung cancer and explored its role in cell proliferation. S100A11 mRNA level was examined in 45 pairs of frozen lung cancer tissues by reverse transcriptase PCR (RT-PCR). The specific expression and subcellular distribution of S100A11 were examined in 78 paraffin-embedded lung cancers, 2 benign lung diseases as well as 22 healthy lung tissues by immunohistochemistry. S100A11 protein level was further analyzed in the sera of 86 lung cancer patients and 50 healthy individuals by enzyme-linked immunosorbent assay. We found that both mRNA and protein levels of S100A11 were overexpressed in adenocarcinomas (ADC) and squamous cell carcinomas (SCC) compared with paired non-cancerous lung tissues, while S100A11 was detected downregulated in small cell lung cancers (SCLC). Further immunohistochemistry staining was positive for S100A11 only in non-small cell lung cancer (NSCLC) (ADC, SCC, large cell carcinomas, et al.), but not SCLC. Conclusively, we found S100A11 protein level increased in the sera of NSCLC patients. Furthermore, when S100A11 expression was knocked down in lung adenocarcinoma cells A549 and LTEP-a-2, the cell proliferation was significantly inhibited in vitro and in vivo.

CABYR is a novel cancer-testis antigen in lung cancer.

Purpose: Cancer-testis (CT) antigens are often expressed in a proportion of tumors of various types. Their restricted normal tissue expression and immunogenicity make them potential targets for immunotherapy. CABYR is a calcium-binding tyrosine phosphorylation–regulated fibrous sheath protein initially reported to be testis specific and subsequently shown to be present in brain tumors. This study was to determine whether CABYR is a novel CT antigen in lung cancer. Experimental Design: mRNA expression of CABYR-a/b (combination of CABYR-a and CABYR-b) and CABYR-c was examined in 36 lung cancer specimens, 14 cancer cell lines, and 1 normal cell line by conventional and real-time reverse transcription-PCR. Protein expression of CABYR was analyzed in 50 lung cancer tissues by immunohistochemistry. Antibodies specific to CABYR were analyzed in sera from 174 lung cancer patients and 60 healthy donors by ELISA and Western blot. Results: mRNA expression of CABYR-a/b and CABYR-c was observed, respectively, in 13 and 15 of 36 lung cancer tissues as well as in 3 and 5 of 14 cancer cell lines, whereas neither of them was observed in adjacent noncancerous tissues or the normal cell line. Protein expression of CABYR-a/b and CABYR-c was observed, respectively, in 20 and 19 of 50 lung cancer tissues. IgG antibodies specific to CABYR-a/b and CABYR-c were detected, respectively, in 11% and 9% of sera from lung cancer patients but not from the 60 healthy donors. Conclusion: CABYR is a novel CT antigen in lung cancer and may be a promising target for immunotherapy for lung cancer patients.

A combined biomarker pattern improves the discrimination of lung cancer

A total of 227 sera were analysed using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) to find novel serum biomarkers for lung cancer. The results showed that the 11.53, 11.70, 13.78, 13.90 and 14.07 k m/z peaks identified as native serum amyloid A (SAA), SAA with N-terminal Arg cleaved, native transthyretin (TTR) and its two variants significantly differentiated lung cancer sera from normal control sera (p <0.01). A ‘biomarker pattern’ combining SAA and TTR was tested to distinguish lung cancer patients from normal control individuals, and the diagnostic positive rate of lung cancer was improved to 91.6%.

Elevated expression of UBE2T in lung cancer tumors and cell lines

The aim of this study was to investigate the association between UBE2T, a member of the ubiquitin-conjugating E2 family, and lung cancer, which has never been reported to date. Therefore, the expression of UBE2T mRNA was examined in normal human tissues and 8 lung cancer cell lines. Subsequently, UBE2T expression was analyzed in 41 lung cancer tissues by PCR and Western blots, as well as in 103 lung cancer specimens by immunohistochemistry. To further elucidate the possible functional role of UBE2T, the protein was overexpressed in NIH3T3 cells. UBE2T mRNA was highly expressed in all lung cancer cell lines examined, while it could not be detected in normal lung tissue. UBE2T was detected in 75.6% of primary lung cancer tissue samples (n = 41) at mRNA level and in 60.9% at protein level. In addition, positive UBE2T staining was observed in 61% of lung cancer specimens (n = 103), particularly in all immunohistochemically stained small cell carcinoma tissues. In normal lung tissue, only weak staining was observed in the basal cells of bronchial epithelium. Overexpression of UBE2T in NIH3T3 cells significantly promoted colony formation in soft agar medium (p < 0.001). In conclusion, UBE2T was significantly upregulated in lung cancer tissue and cell lines, suggesting involvement of UBE2T in the malignant cell phenotype.

A High-Temporal Resolution Technology for Dynamic Proteomic Analysis Based on 35S Labeling

As more and more research efforts have been attracted to dynamic or differential proteomics, a method with high temporal resolution and high throughput is required. In present study, a 35S in vivo Labeling Analysis for Dynamic Proteomics (SiLAD) was designed and tested by analyzing the dynamic proteome changes in the highly synchronized A549 cells, as well as in the rat liver 2/3 partial hepatectomy surgery. The results validated that SiLAD technique, in combination with 2-Dimensional Electrophoresis, provided a highly sensitivity method to illustrate the non-disturbed endogenous proteins dynamic changes with a good temporal resolution and high signal/noise ratio. A significant number of differential proteins can be discovered or re-categorized by this technique. Another unique feature of SiLAD is its capability of quantifying the rate of protein expression, which reflects the cellular physiological turn points more effectively. Finally, the prescribed SiLAD proteome snapshot pattern could be potentially used as an exclusive symbol for characterizing each stage in well regulated biological processes.

Triple labeling with three thymidine analogs reveals a well-orchestrated regulation of hepatocyte proliferation during liver regeneration

Aim:  After a two‐thirds partial hepatectomy (PHx) in rodents, the remaining cells will proliferate and restore the lost liver mass within 7 days. Previous studies have proved that the residual hepatocytes proliferate in a synchronous manner. However, the existing data can not reflect the chronicle of individual hepatocytes proliferation during liver regeneration.

Doxycycline enhances the Ras‐MAPK signaling and proliferation of mouse thymic epithelial cells

Depletion of T‐cell‐dependent immunity is a major consideration for patients suffering from infections of human immunodeficiency virus (HIV), those undergoing organ transplantation, and those receiving anti‐cancer chemotherapy and/or radiotherapy. In general, T‐cell regeneration occurs in the thymus through thymopoiesis. We have found that doxycycline (Dox), a tetracycline derivative, enhances the proliferation of mouse thymic epithelial cells, which are unique in their capacity to support positive selection and are essential throughout the development of thymocytes. Cell cycle analysis indicates that the increased cell proliferation is due to a shortened G0/G1 phase. To reveal the underlying mechanisms, we examined the expression of an array of molecules that regulate the cell cycle. The results show that in mouse thymic medullary‐type epithelial cell line 1 (MTEC1) Dox leads to elevated levels of H‐Ras, phosphorylated extracellular signal‐regulated kinase 1/2 (p‐ERK1/2), cyclin E, cyclin dependent kinase 4/2 (CDK4/CDK2), E2F3, and c‐myc. These data, and the observation that the proliferation‐enhancing effect is largely abolished following treatment with an ERK inhibitor support an active role of the Ras‐ERK/mitogen‐activated protein kinase (MAPK) signaling pathway. In conclusion, the present study reveals a new activity of an old family of antibiotics. The in vivo effect of Dox on immune reconstitution warrants further exploration. J. Cell. Biochem. 107: 494–503, 2009.