Cytokine IL-6 is required in Citrobacter rodentium infection-induced intestinal Th17 responses and promotes IL-22 expression in inflammatory bowel disease.

Citrobacter rodentium (C. rodentium) infection is a widely used murine model to mimic human enteric bacteria infection and inflammatory bowel disease (IBD). In this model, interleukin (IL)­17A plays critical roles in increasing chemokine and cytokine production in various tissues to recruit innate cells, including monocytes and neutrophils, to the local site of infection. However, the source of IL­17A remains unclear, as the majority of cell types produce IL­17A, including intestinal endothelium cells, innate immune cells and CD4+ T cells in disease development. In the current study, wild­type B6 mice were treated with C. rodentium and the CD4+ Th17 cell subset was observed as being specifically increased in Peyer's patches (PP), but not in mesenteric draining lymph nodes. Furthermore, the research suggested that the differentiation and activation of Th17 cells in PP were dependent on the inflammatory cytokine IL­6, as blocking IL­6 signaling with neutralizing antibodies decreased Th17 cells and resulted in the mice being more susceptible to C. rodentium infection. These results confirmed that the Th17 cell subset was specifically activated in PP and demonstrated that IL­6 is required in Th17 cell activation, which are important to the clinical treatment of IBD.

Analysis of differentially expressed genes in LNCaP prostate cancer progression model.

The LNCaP/C4-2 human prostate cancer progression model was established to mimic phenotypic and genotypic changes during prostate cancer development from androgen dependence to androgen independence, from nonmetastasis to metastasis. In this study, cDNA microarrays were performed using a microarray chip from Affymetrix to characterize and compare gene expression profiles in LNCaP and C4-2, which may provide novel insight into the molecular mechanism mediating prostate cancer progression. Three hundred eighteen genes consistently exhibited differential expression in LNCaP and C4-2 in 2-time microarray data. Based on their function, the differentially expressed genes can be grouped into several subcategories, including growth factors and signal transducers, oncogenes and tumor suppressors, tumor-specific antigens, transcriptional factors, transporters, and factors involved in invasion, metastasis, and metabolism. Some genes are novel and unexplored in prostate cancer progression and are of potential interest for follow-up investigation. Reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR were performed to corroborate the microarray results, and 76 differentially expressed genes were validated out of 104 candidates. Expression pattern analyses were performed in these 76 differentially expressed genes, and a series of genes was found to be positively or negatively correlated to prostate cancer progression in the LNCaP prostate cancer progression model and to possess predominant prostate cell specificity. ELF5/ESE-2b and long-chain acyl coenzyme A dehydrogenase (ACADL) expressions were found to be positively associated with malignant progression in LNCaP, C4-2, and C4-2B, and predominantly expressed in prostate cancer cells. Functional evaluation revealed that ELF5/ESE-2b and ACADL expressions contributed to the malignant phenotypes of prostate cancer cells. Accordingly, our microarray data may provide clues for finding novel genes involved in prostate cancer progression to androgen independent and metastasis, and shed light on finding new targets for diagnosis and therapy of prostate cancer.

[PC-1 enhances c-myc gene expression in prostate cancer cells].

PC-1(Prostate and colon gene 1) gene belongs to TPD52 (Tumor Protein D52) gene family. The expression of PC-1 is found to promote androgen-independent progression. This study was conducted to assess the mechnism of promotion of androgen-independent progression in PC-1 gene. The c-myc gene expression was tested by RT-PCR and Western blotting analyses in the LNCaP-pc-1 and LNCaP-zero cell line. After separation of cytoplasm and nulear proteins of the LNCaP-pc-1 and LNCaP-zero cell line, the beta-catenin protein was detected by Western blotting. C4-2 cell line was used to examine the effects of 10058-F4 on the PC-1 gene expression. The results of RT-PCR and Western blotting indicated that PC-1 enhanced c-myc gene expression in prostate cancer cells, PC-1 was also found to enhance beta-catenin expression in nuclear. Furthermore, a small-molecule c-Myc inhibitor, 10058-F4 represses PC-1 gene expression in C4-2 cell line. Our findings suggest that PC-1 enhances c-myc gene expression in prostate cancer cells through the Wnt/beta-catenin pathway. Meanwhile, c-myc plays a feed-forward role in enhancing PC-1 driven c-myc gene expression, and promotes prostate an-drogen-independent progression.

[Identification and expression of two new secretory proteins associated with prostate cancer].

Our research intends to obtain extra-cellular proteinogram of cell lines representing different advancement stages of prostate cancer and to test whether screened differential expression proteins can be secreted and used as serum biomarkers for prostate cancer. By examining differential expression spots in two extra-cellular protein 2D-PAGE gels and mass spectrum, candidate molecules were obtained. The expressions of these candidate molecules in eight cell lines and response to androgen stimulus in LNCaP were analyzed by RT-PCR. By constructing eukaryotic expression vectors and western-blotting with anti tags antibodies, the candidate molecules were tested to understand whether they can be expressed in transfected 293T cell culture fluid. Two overexpressed molecules-triosephosphate isomerase 1 (TPI1) and syndecan bind-ing protein, syntenin (ST1)-in extra-cellular proteinogram of C4-2 were screened out; both of them are secretary proteins. On transcriptional level, both proteins were up-regulated with the malignancy of prostate cancer cell lines and ST1 was dose-dependently inhibited by androgen. Considering cellular level results, both TPI1 and ST1 have their potential as serum biomarkers for indicating the developmental stage of prostate cancer.

The radiation response of androgen-refractory prostate cancer cell line C4-2 derived from androgen-sensitive cell line LNCaP.

Radiation therapy is a relatively effective therapeutic method for localized prostate cancer (PCa) patients. However, radioresistance occurs in nearly 30% of patients treated with potentially curative doses. Therapeutic synergy between radiotherapy and androgen ablation treatment provides a promising strategy for improving the clinical outcome. Accordingly, the androgen deprivation-induced signaling pathway may also mediate radiosensitivity in PCa cells. The C4-2 cell line was derived from the androgen-sensitive LNCaP parent line under androgen-depleted condition and had acquired androgen-refractory characteristics. In our study, the response to radiation was evaluated in both LNCaP and C4-2. Results showed that C4-2 cells were more likely to survive from irradiation and appeared more aggressive in their resistance to radiation treatment compared with LNCaP, as measured by clonogenic assays and cell viability and cell cycle analyses. Gene expression analyses revealed that a set of genes involved in cell cycle arrest and DNA repair were differentially regulated in LNCaP and C4-2 in response to radiation, which was also consistent with the radiation-resistant property observed in C4-2 cells. These results strongly suggested that the radiation-resistant property may develop with progression of PCa to androgen-independent status. Not only can the LNCaP and C4-2 PCa progression model be applied for investigating androgen-refractory progression, but it can also be used to explore the development of radiation resistance in PCa.

Ubiquitous mitochondrial creatine kinase is overexpressed in the conditioned medium and the extract of LNCaP lineaged androgen independent cell lines and facilitates prostate cancer progression.

BACKGROUND: Androgen independent prostate cancer (AIPC) is not responsive to androgen ablation therapy. The biomarkers of AIPC are lack. Numerous proteomics studies have focused on finding new markers of AIPC and exploring their possible functions, but little is known about the difference between conditioned medium (CM) from AIPC and androgen dependent prostate cancer (ADPC) cells. METHODS: We performed a proteome analysis of CM from LNCaP, C4-2, and C4-2B cells by a two dimensional electrophoresis based technology. Western blots and immunohistochemical studies were employed to explore the expression pattern of the identified protein in prostate cancer cell lines and clinical specimens, respectively. Then we examined the possible roles and mechanisms of the ubiquitous mitochondrial creatine kinase (uMtCK) in vitro. RESULTS: Besides prostate specific antigen (PSA) and insulin-like growth factor binding protein-2 (IGFBP2), uMtCK was identified in the CM of AIPC cells. uMtCK was up-regulated in AIPC cells and in human prostate cancer tissues at WHO grade III. Stably transfected exogenous uMtCK showed a growth promoting effect rather than mock vector in LNCaP cells, with or without bicalutamide in culture medium. Further assays showed that higher degrees of ROS generation and Akt signaling pathway activation in LNCaP-uMtCK than in LNCaP-neo cells. CONCLUSIONS: We showed that uMtCK could be easily detected in CM of LNCaP lineaged AIPC cells. Exogenous uMtCK in LNCaP cells surprisingly contributed to overproduction of ROS, activation of Akt signaling pathway and more aggressive phenotypes including androgen independence development.

[Gene fusion of egfp & kan and recombinant plasmid construction by red mediated in vivo homologous recombination].

Recombineering, a new genetic engineering technology based on high efficiency in vivo homologous recombination, can be used in target DNA knock-in, knock-out and gene cloning. In the process of gene subcloning mediated by Recombineering technique, high-quality target DNA fragments were difficult to obtain using in vitro overlapping PCR,therefore the efficiency of in vivo homologous recombination was severely interrupted. To solve this problem, some technology improvements have been established based on the principle of Red recombinases. The PCR DNA fragments of egfp and kan genes with complementary sequences on the end of each fragment were co-introduced into a pcDNA3.1 vector and Red recombinases containing E. coli DY331 host cells by electroporation. A recombinant plasmid pcDNA3.1-egfp-kan was screened directly by antibiotic marker. The positive rates can reach to 45%. The EGFP gene expression of pcDNA3.1-egfp-kan can be observed by transient transfection of 293 eukaryotic cells.

Identification and characterization of the novel human prostate cancer-specific PC-1 gene promoter.

Human prostate and colon gene-1 (PC-1, also known as PrLZ) is an androgen-regulated, prostate tissue and prostate cancer cells specifically expressed novel gene. The increased expression of PC-1 gene appears to promote prostate cancer cells androgen-dependent (AD) and androgen-independent (AI) growth. To clone and investigate the expression and regulation elements of PC-1 gene may provide insight into the function of PC-1 and develop a new promoter that targets therapeutic genes to the AD and AI prostate cancer cells. The goal of the present study is cloning and characterization of the PC-1 promoter. A series of luciferase constructs that contain various fragments of the PC-1 5'-genomic region were transfected into human prostate cancer cells for promoter transactivation analysis. 5' deletion analysis identified the -1579 bp promoter region was required for the maximal proximal promoter activity; two transcriptional suppression and a positive regulatory region were identified; -4939 bp promoter fragment of the PC-1 gene retained the characteristic of prostate cancer-specific expression and exhibited higher transcription activity than PSA-6 kb promoter in the medium supplemented with steroid-depleted FBS. An androgen response element (ARE) was located in between -345 and -359 bp of the PC-1 5'-untranslated region relative to the translation initiation site. Thus, our studies not only provide molecular basis of PC-1 transcription regulation, but also define a new regulatory sequence that may be used to restrict expression of therapeutic genes to prostate cancer in the prostate cancer gene therapy.