OSI-027 inhibits the tumorigenesis of colon cancer through mediation of c-Myc/FOXO3a/PUMA axis.

Colon cancer is a gastrointestinal malignancy that is one of the leading causes of tumor-associated deaths. It has been reported that the mammalian target of rapamycin (mTOR) can lead to the progression of colon cancer. However, the mechanism by which mTOR inhibitor (OSI-027) mediates the tumorigenesis of colon cancer remains largely unknown. Cell function of colon cancer was investigated by cell counting kit-8 flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling staining. In addition, quantitative real-time polymerase chain reaction and Western blot were used to investigate the mechanism underlying the function of OSI-027 in colon cancer. OSI-027 dose-dependently reduced colon cancer cell viability by inducing cell apoptosis. In addition, OSI-027 induced the apoptosis of colon cancer cells via upregulation of PUMA. OSI-027 promoted the expression of PUMA by activation of forkhead box protein O3a (FOXO3a), and c-Myc knockdown partially increased FOXO3a and PUMA levels. Moreover, OSI-027 attenuated the tumor growth of colon cancer through the mediation of the mTOR/c-Myc/FOXO3a axis. OSI-027 attenuates colon cancer progression through the mediation of the c-Myc/FOXO3a/PUMA axis. Thereby, this study might shed new insights on exploring the strategies against colon cancer.

Correlation between procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 and breast cancer.

Procollagen-lysine, 2-oxoglutarate 5-dioxygenase 2 (PLOD2), which affects collagen synthesis, is associated with breast cancer. The purpose of the study is to detect the expression of PLOD2 in breast cancer and to evaluate the correlation between PLOD2 and clinicopathologic characteristics and prognosis of patients with breast cancer. 50 paired samples including breast cancer tissues and adjacent non-tumor tissues were formalin-fixed and evaluated by immunohistochemistry. The results revealed that PLOD2 expression in breast cancer tissues was much higher than that in tissues adjacent to breast cancer. High expression of PLOD2 was positively associated with tumor stage (P = 0.003) and lymph node metastasis (P = 0.001). However, high expression of PLOD2 was negatively related to Ki-67 (P < 0.001) while positively related to progesterone receptor (PR) (P = 0.001). PLOD2 expression was positively related to the metastasis of breast cancer. Therefore, high expression of PLOD2 was identified as a poor prognostic biomarker for patients with breast cancer. These results suggest a novel molecular mechanism in breast cancer tumorigenesis, thus providing a potential therapeutic target of breast cancer.

Highly sensitive detection of cancer-related genes based on complete fluorescence restoration of a molecular beacon with a functional overhang.

The accurate detection of cancer-related genes is of great significance for early diagnosis and targeted therapy of cancer. In this contribution, an automatically cycling operation of a functional overhang-containing molecular beacon (OMB)-based sensing system was proposed to perform amplification detection of the p53 gene. Contrary to the common molecular beacon (MB), a target DNA is designated to hybridize with a label-free recognition probe (RP) with a hairpin structure rather than OMB. In the presence of a target DNA of interest, the locked primer in RP opens and triggers the subsequent amplification procedures. The newly-developed OMB is not only capable of accomplishing cyclical nucleic acid strand-displacement polymerization (CNDP) with the help of polymerase and nicking endonuclease, but is also cleaved by restriction endonucleases, removing the quencher away from the fluorophore. Thus, the target DNA at an extremely low concentration is expected to generate a considerable amount of double-stranded and cleaved OMBs, and the quenched fluorescence is completely restored, leading to a dramatic increase in fluorescence intensity. Utilizing this sensing platform, the target gene can be detected down to 8.2 pM in a homogeneous way, and a linear response range of 0.01 to 150 nM could be obtained. More strikingly, the mutant genes can be easily distinguished from the wild-type ones. The proof-of-concept demonstrations reported herein are expected to promote the development of DNA biosensing systems, showing great potential in basic research and clinical diagnosis.

[Virological impact of stalk region of neuraminidase in influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses].

This study aims to investigate the virological impact of the stalk region and cysteine (C) in neuraminidase (NA) of influenza A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1) viruses. The NA of A/ Anhui/1/05 (H5N1), defined as AH N1, lacked 20 amino acids (including C, defined as s20) as compared with NA of A/Ohio/07/2009 (H1N1) (defined as 09N1). We deleted s20 of 09N1 to construct 09N1-s20, and inserted s20 into AH N1 to construct AH N1+s20. To investigate the impact of C on the biological function of NA, we deleted C in 09N1 to construct 09N1-C and inserted C into AH N1 to construct AH N1-C. The pseudo-type viral particle (pp) system was used to evaluate the impact of these mutants on virology. The combination of 09N1-C and 09H1 (defined as 09H1::09N1-C) showed an infectivity 8 times that of the wild type 09H1::09N1, while the infectivity of the combination of AH N1+C and AH H5 (defined as AH H5::AH N1+C) was much lower than that of the wild type AH H5::AH N1. The infectivity of the combination of 09N1-s20 and 09H1 (defined as 09H1::09N1-s20) was 4 times that of the wild type 09H1::09N1; the infectivity of the combination of AH N1+s20 and AH H5 (defined as AH H5:: AH N1+s20) was 1/7 that of the wild type AH H5::AH N1. The co-existence of 09N1-C and AH H5 displayed 6 times the infectivity of AH H5::09N1, while the infectivity of 09H1::AH N1+C was very low. Multimer analysis showed that in the wild type 09N1, the forms of NA were dimer >> tetramer > monomer; the major component of NA in 09N1-C was monomer; in 09N1-s20, the forms of NA were monomer >> dimer. AH N1 was mainly composed of monomer; in AH N1+s20, the forms of NA were dimer >> monomer > tetramer; in AH N1+C, the forms of NA were dimer >> tetramer. Deletion of C or s20 from 09N1 did not change the expression of NA. The study suggested that deletion of C from the stalk region of NA in A/Ohio/07/2009 (H1N1) increases infectivity. Insertion of C into NA's stalk region of A/ Anhui/1/05 (H5N1) significantly decreases infectivity. Cysteine deletion in the stalk region is important for the infectivity of A/Anhui/1/05 (H5N1) and A/Ohio/07/2009 (H1N1). It may interfere with the infectivity via changes in NA polymerization.

[Detection of WU polyomavirus in children with low respiratory tract infections using real-time fluorescent quantitative PCR].

OBJECTIVE: Development and application of a real time fluorescent quantitative PCR (FQ-PCR) assay for detecting WU polyomavirus in children with low respiratory tract infections. METHODS: The VP2 gene of WU polyomavirus was selected as the detection target, from which the real time primers and probes were designed. The standard curve was established by using recombinant plasmid as template. And the FQ-PCR assay for specific detection of WU polyomavirus was established. The specificity, sensitivity and reproducibility of the method were evaluated. Furthermore, the clinical specimens from children with respiratory tract infections collected in Wenling First People's Hospital were quantitatively detected using this method. RESULTS: In this study, the FQ-PCR method was established to detect a specific fragment in VP2gene of WU polyomavirus. The standard curve coefficient R2 was 0.998. And this method can detect as low as 50 copies recombinant plasmid. The clinical specimens of sputum and throat swab from children with respiratory tract infections were quantitatively detected using this method. 7 sputum specimens were detected as WU polyomavirus positive in 700 sputum specimens, the positive ratio was 1.00%. No positive specimens were detected in 146 specimens of throat swabs and 846 blood samples from same patient population. CONCLUSION: The results indicated that the FQ-PCR assay method established in this study was specific, rapid and sensitive for detecting WU polyomavirus in children with lower respiratory tract infections. The sputum specimen is more suitable to be used for gene detection of WU polyomavirus than throat swab or blood.

[Development and identification of polyclonal antibodies against HIV-1 Vpr-derived polypeptides].

To develop polyclonal antibodies against predicted B cell epitopes in HIV-1 accessory protein Vpr, the prepared consensus Vpr amino acid sequence was used to predict potential B cell epitopes by online softwares (ABCpred and Bcepred), the synthesized polypeptides of B-cell epitopes were subsequently conjugated with keyhole limpet hemocyanin (KLH) and then used to immunize rabbits. The antibody titers were determined by ELISA, and antibody specifity was analyzed by Western-Blotting and immunoprecipitation, respectively. Amino acid residues 3-19 (N) and 82-95 (C) of Vpr were predicted as the potential B cell epitopes. After inoculation of the conjugation of synthesized peptide to KLH, the antibody titers in rabbit sera against N and C peptides reached more than 1:100000 by ELISA. Western-Blotting analysis showed that the polyclonal antibodies reacted with both wild Vpr and fusion protein of GFP with Vpr, no matter Vpr was derived from HIV-1 B subtype or CRF07_BC recombinant form; Immunoprecipitation analysis showed similar reactions to Western-Blotting results. Two B cell epitopes of Vpr were successfully predicted by Bio-informatics methods and polyclonal antibodies against those peptides could be successfully prepared.

[Effects of Lin28a and Lin28b on let-7 family activity].

In this report, we study the effects of over-expression of Lin28a and Lin28b on let-7 family activity in HeLaS3. Firstly, we constructed pAAV2neo-Lin28a and pAAV2neo-Lin28b to express Lin28a and Lin28b, respectively. Then, pAAV2neo-Lin28a and pAAV2neo-Lin28b were transfected into HeLaS3, selected with G418 and obtained cell lines, HeLaS3/pAAV2neo-Lin28a and HeLaS3/pAAV2neo-Lin28b, to express Lin28a and Lin28b stably. Thereafter, we constructed eight plasmid vectors for detection of let-7 family activity based on pAAV2neo-Gluc-(Fluc). These vectors were further packaged into recombinant adeno-associated viral vectors (rAAV) which were used as sensors, nominated as Asensors, to detect inhibition activity of miRNA at post-transcriptional level. Subsequently, with HeLaS3 as a control, we assayed expression levels of Lin28a and Lin28b by Western blot, detected expression levels of let-7 family by QRT-PCR, and tested let-7 family activity by Asensors in HeLaS3/pAAV2neo-Lin28a and HeLaS3/pAAV2neo-Lin28b. Results demonstrated that both HeLaS3/pAAV2neo-Lin28a and HeLaS3/pAAV2neo-Lin28b could express Lin28a and Lin28b effectively. Compared with HeLaS3, the expression level of let-7 family except let-7e declined in HeLaS3/pAAV2neo-Lin28a. But declining extent among members of let-7 family was different. The let-7 family activity also decreased while the decreasing extent varied among members. Furthermore, the activity level was not consistent with its expression level for the same member in let-7 family. Compared with HeLaS3, both expression level and activity level of let-7 family in HeLaS3/ pAAV2neo-Lin28b were decreased. However, the decreasing extent of let-7 family expression changes was larger than that of HeLaS3/pAAV2neo-Lin28a while the decreasing extent of activity changes was similar. In this study, we established a method to detect and compare post-transcriptional inhibition level mediated by miRNA complementary targets. We firstly clarified the effect of Lin28a and Lin28b on let-7 family activity profile and found that this effect was not the same as that at expression level of let-7 family, suggesting that it was more comprehensive to understand miRNA regulation roles to detect both miRNA expression and activity. This paves a way for further research on mechanism of regulation of let-7 family.

[Detection of adenoviruses in feces of infants with diarrhea by real-time PCR].

OBJECTIVE: A Real-time PCR method was established to study the infection of adenovirus (Ad) in infants with sporadic diarrhea in Wenzhou. METHODS: According to hexon gene of adenovirus, one prime pair was designed as universal primes and applied to detect adenovirus DNA by Real-time PCR. It was also compared with immunochromatographic assay. 157 fecal specimens from diarrhea infants were tested while positive specimens were sequenced and identified by isolate culture and restriction endonucleases. RESULTS: A rapid and specific Real-time PCR assay for detection adenovirus was set up. The positive rates of adenovirus in fecal specimens by immunochromatographic assay and Real-time PCR were 1.91% (3/157) and 3.18% (5/157), respectively. Out of the 154 specimens with negative result from immunochromatographic assay, 2 showed positive by Real-time PCR. 5 positive specimens, identified by Real-time PCR, were sequenced as Ad3 (3/157, 1.91% ) and Ad7 (2/157, 1.27%). 2 of the 5 positive specimens were proved to be Ad3 by cell culture and restriction endonucleases. CONCLUSION: Real-time PCR combined with sequence analysis seemed more sensitive and specific so could be used for identifying types of adenovirus in clinical specimens. Ad3 and Ad7 were important pathogens which caused infant sporadic diarrhea in Wenzhou during February and April in 2008.