Repositioning of a cyclin-dependent kinase inhibitor GW8510 as a ribonucleotide reductase M2 inhibitor to treat human colorectal cancer.

Colorectal cancer (CRC) is the second leading cause of cancer-related death in males and females in the world. It is of immediate importance to develop novel therapeutics. Human ribonucleotide reductase (RRM1/RRM2) has an essential role in converting ribonucleoside diphosphate to 2'-deoxyribonucleoside diphosphate to maintain the homeostasis of nucleotide pools. RRM2 is a prognostic biomarker and predicts poor survival of CRC. In addition, increased RRM2 activity is associated with malignant transformation and tumor cell growth. Bioinformatics analyses show that RRM2 was overexpressed in CRC and might be an attractive target for treating CRC. Therefore, we attempted to search novel RRM2 inhibitors by using a gene expression signature-based approach, connectivity MAP (CMAP). The result predicted GW8510, a cyclin-dependent kinase inhibitor, as a potential RRM2 inhibitor. Western blot analysis indicated that GW8510 inhibited RRM2 expression through promoting its proteasomal degradation. In addition, GW8510 induced autophagic cell death. In addition, the sensitivities of CRC cells to GW8510 were associated with the levels of RRM2 and endogenous autophagic flux. Taken together, our study indicates that GW8510 could be a potential anti-CRC agent through targeting RRM2.

Abrogation of delayed type hypersensitivity response to Candida albicans produced by a molecular mimic of phosphorylated prolactin.

The effects of two major forms of prolactin (PRL) were examined on delayed type hypersensitivity (DTH) responses to Candida albicans. Unmodified PRL (U-PRL) had no effect on the DTH response, whereas a molecular mimic of phosphorylated PRL (S179D PRL) significantly inhibited immune responses to this robust antigen. This effect of S179D PRL was not accompanied by gross alterations in splenic T cell numbers, CD4/CD8 ratios, or T and B cell activation markers, but did produce a decrease in splenocyte apoptosis. Using gld animals, Fas ligand (FasL) was implicated in the suppressive effects of S179D PRL. Circulating IgG1 and IgG2 antibody levels were increased in response to treatment with both forms of PRL, but the effects of S179D PRL were most pronounced. Cytokine changes in the popliteal lymph nodes specific to S179D PRL treatment showed an inhibition of pro-inflammatory cytokines. In conclusion, mice treated with a molecular mimic of phosphorylated prolactin showed a profound inhibition of DTH responses to Candida correlating with an absence of GM-CSF, IL-4, and IL-13 production and a marked reduction in IL-12p70 synthesis.

The dual roles of Armigeres subalbatus prophenoloxidase V in parasite melanization and egg chorion melanization in the mosquito Ar. subalbatus.

Phenoloxidases (POs) play key roles in various physiological functions in insects, e.g., cuticular sclerotization, wound healing, egg tanning, cuticle formation and melanotic encapsulaction of pathogens. Previously, we identified five POs, designated As-pro-PO I-V, from the mosquito Armigeres subalbatus and demonstrated that the functions of As-pro-PO I, II and III, were associated with filarial parasite melanization, blood feeding and cuticle formation, respectively. In the present study, we delineate the dual functions of As-pro-PO V. We found that the level of As-pro-PO V mRNA in mosquitoes was significantly increased after microfilaria challenge or blood feeding, and decreased to normal level after oviposition. Knockdown of As-pro-PO V by dsRNA resulted in significant decreases in the degree of microfilaria melanization, egg chronic melanization rates and egg hatching rates in Ar. subalbatus. Further transfection and electrophoretic mobility-shift assays verified the As-pro-PO V gene might regulated by both AP-1, a putative immune-related regulatory element and CdxA, a developmental regulatory element. The binding of AP-1 and CdxA motif with mosquito nuclear extracts was significantly enhanced after microfilaria challenge and blood-feeding in Ar. subalbatus, respectively. These results indicate that As-pro-PO V is a critical enzyme that is required for both an effective melanization immune response and egg chorion melanization in this mosquito.

Thoracoplasty with acrylic plate-marlex mesh combination following near total resection of sternum: a case of chondrosarcoma of sternum.

Removal of the whole sternum for malignant tumours results in a large defect, causing severe deformity and possible paradoxical movements of the chest wall. The reconstruction of the resultant large defect of the chest wall is often complex and difficult. Commonly used materials include rib autograft, steel strus acrylic plate and various synthetic meshes such as Goretex or Marlex mesh, with a myocutaneous flap for coverage. A case of a 48-year-old man with sternal chondrosarcoma successfully treated with thoracoplasty using acrylic plate-marlex mesh combination following near total resection of sternum is reported.

Skin-sparing mastectomy.

Skin-sparing mastectomy is still in its infancy in Malaysia. The option of skin-sparing mastectomy is rarely given to patients as many general surgeons perform the conventional mastectomy. This could also be compounded by the lack of awareness amongst the local surgeons on the safety, surgical technique and treatment outcome of this relatively new procedure. This case report demonstrates the feasibility of this procedure performed on a Malaysian patient with a comparable outcome of those reported in the Western countries.

Indoor air pollution from solid fuel and tuberculosis: a systematic review and meta-analysis.

OBJECTIVE: To conduct an updated systematic review and meta-analysis on the association between indoor air pollution and tuberculosis (TB). DESIGN: We searched for English or Chinese articles using PubMed and EMBASE up to 28 February 2013. We aimed to identify randomised controlled trials and observational epidemiological studies that reported the association between domestic use of solid fuel and TB. Two reviewers independently extracted the information from included studies and assessed the risk of bias of these studies using pre-defined criteria. The effect sizes of eligible studies were pooled using a random-effects model; the heterogeneity across studies was quantified using I(2) statistics. RESULTS: We identified 15 studies on solid fuel use and active TB and one on solid fuel use and latent tuberculous infection. The summary odds ratios from case-control and cross-sectional studies were respectively 1.17 (95%CI 0.83 - 1.65) and 1.62 (95%CI 0.89 - 2.93), with substantial between-study heterogeneity (I(2) 56.2% and 80.5%, respectively). Subgroup analysis and meta-regression analysis did not identify any study-level factors that could explain the heterogeneity observed. CONCLUSION: The level of evidence for the association between domestic use of solid fuels and TB was very low. High-quality studies are badly needed to clarify this association and to estimate the magnitude of the problem.

Inhibition of HIV-1 replication with designed miRNAs expressed from RNA polymerase II promoters.

Small interfering RNA (siRNA) mediates sequence-specific RNA cleavage and represents a potential approach to treat the infection of human immunodeficiency virus (HIV). Expression of a single siRNA species frequently led to the emergence of HIV escape variants. Thus, multiple siRNAs targeted to different regions in the HIV-1 genome may be required. However, overexpression of different anti-HIV siRNA genes from multiple pol III promoters can induce cell toxicity, thus may not be a viable option in the setting of human gene therapy trials. In the current study, we evaluated the strategy of using pol II promoters to drive the expression of siRNAs against HIV-1. We replaced the stem sequence in the stem-loop structure of the well-characterized miR-30a with siRNA sequences and showed that designed microRNA (miRNA) could be expressed from pol II promoters. We demonstrated efficient inhibition of HIV-1 replication with such designed miRNA, but the efficacy was directly correlated with the expression level. Both the vector copy number and the promoter strength directly affected the ability of the siRNA to inhibit HIV-1 replication. We also showed that a combination of pol II and pol III promoters to express two different siRNAs increased the efficacy against HIV-1 replication without comprising cell viability.

Serotyping of Clostridium difficile.

A total of 246 live Clostridium difficile cultures were serotyped by a slide agglutination technique. Fifteen grouping antisera were produced which serotyped 98% of the cultures (241 of 246). Our results indicated that certain serogroups may have specific pathogenicity. Strains of serogroups A, G, H, K, S1, and S4 were cytotoxigenic and were isolated mainly from adult patients with pseudomembranous colitis or antibiotic-associated diarrhea. Nontoxigenic strains of serogroups D and Cd-5 were isolated mainly from asymptomatic neonates and small children. Some cross-reactions occurred among some strains of serogroups A, Cd-5, G, and K. These strains were further examined by analysis of protein profiles and restriction endonuclease patterns to elucidate their serology. Typing of C. difficile by using slide agglutination is a simple technique suitable for routine examination. Serogrouping may be a useful epidemiological marker and could help in elucidating the medical relevance of some C. difficile isolates.