RESUMEN
INTRODUCTION: The human JC polyomavirus (JCPyV) has been detected in colorectal cancer (CRC) tissues and is suggested to contribute to CRC tumorigenesis. The rearrangement of the JCPyV regulatory region is supposedly associated with CRC development. The progression of CRC involves the stepwise accumulation of mutations. The large tumor antigen (LT) of JCPyV can trigger uncontrolled cell cycle progression by targeting oncogenes, and tumor suppressor genes, and causing chromosome instability. Few studies have focused on the presence of JCPyV DNA in the higher grade of CRC tissues. METHODS: We collected 95 tissue blocks from samples of stages I, II, III, and IV CRC. Nested PCR targeting the regulatory region of the viral genome was performed to determine the presence of JCPyV DNA in the various stages of colorectal cancer tissues. RESULTS: The nested PCR results showed that the positive rate of JCPyV DNA increased with the progression of CRC stages. The archetypal-like, non-rearrangement genotype of JCPyV with subtle mutations was the major genotype found in CRC samples. CONCLUSIONS: This finding in our study suggests that there may be an association between JCPyV and CRC progression.
Asunto(s)
Neoplasias Colorrectales , Virus JC , Infecciones por Polyomavirus , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/genética , ADN Viral/genética , Humanos , Incidencia , Virus JC/genética , Infecciones por Polyomavirus/complicaciones , Infecciones por Polyomavirus/epidemiología , Taiwán/epidemiologíaRESUMEN
BH3 domains, classified initially as BCL2 homology domains, participate in both apoptosis and autophagy. Beclin1 contains a BH3 domain, which is required for binding to antiapoptotic BCL2 homologs and BCL2mediated inhibition of autophagy. BCL2like 12 (BCL2L12) also harbors a BH3like domain, which is 12 residues long and contains a LXXXAE/D motif. In a yeast twohybrid system performed in the present study, BCL2L12 shared similar binding partnerships to antiapoptotic BCL2 homologs, such as Beclin1. In addition, this BH3like domain was involved in antiapoptosis and druginduced autophagy in glioma cell lines. Mutations in S156 and hydrophobic L213 to alanine counteracted the antiapoptotic properties of BCL2L12 and downregulated the activation of microtubule associated protein 1 light chain 3B (LC3B), autophagyrelated (ATG)12ATG5 conjugates and Beclin1, compared with a BCL2L12 wildtype group. Molecular dynamics simulations revealed that phosphorylation at Ser156 of BCL2L12 (within α6 and α7 helices) influenced the BH3like domain conformation (α9 helix), indicating that glycogen synthase kinase (GSK) 3ßmediated Ser156 phosphorylation modulated a BH3like domain in BCL2L12. Altogether, the present findings indicated that BCL2L12 may participate in antiapoptosis and autophagy via a BH3like domain and GSK3ßmediated phosphorylation at Ser156. Furthermore, blockade of temozolomide (TMZ)induced autophagy by 3methyladenine (3MA) resulted in enhanced activation of apoptotic markers, as well as tumor suppresor protein p53 (p53) expression in U87MG cells. The present results suggested that p53 and O6methylguanine DNA methyltransferase activation, and BCL2, BCLextra large, Beclin1 and BCL2L12 expression may be used as a detection panel to determine which patients can benefit from TMZ and ABT737 combination treatment.
Asunto(s)
Antineoplásicos Alquilantes/farmacología , Apoptosis/efectos de los fármacos , Autofagia/efectos de los fármacos , Dacarbazina/análogos & derivados , Glioma/tratamiento farmacológico , Glucógeno Sintasa Quinasa 3 beta/metabolismo , Proteínas Musculares/metabolismo , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Línea Celular Tumoral , Dacarbazina/farmacología , Glioma/metabolismo , Glioma/patología , Humanos , Modelos Moleculares , Proteínas Musculares/química , Fosforilación/efectos de los fármacos , Dominios Proteicos/efectos de los fármacos , Mapas de Interacción de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-bcl-2/química , TemozolomidaRESUMEN
GSK3ß interacting protein (GSKIP) is a naturally occurring negative regulator of GSK3ß and retains both the Protein Kinase A Regulatory subunit binding (PKA-RII) domain and GSK3ß interacting domain. Of these two domains, we found that PKA-RII is required for forming a working complex comprising PKA/GSKIP/GSK3ß/Drp1 to influence phosphorylation of Drp1 Ser637. In this study, bioinformatics and experimental explorations re-analyzing GSKIP's biofunctions suggest that the evolutionarily conserved Domain of Unknown Function (DUF727) is an ancestral prototype of GSKIP in prokaryotes, and acquired the C-terminal GSK3ß binding site (tail) in invertebrates except for Saccharomyces spp., after which the N-terminal PKA-RII binding region (head) evolved in vertebrates. These two regions mutually influence each other and modulate GSKIP binding to GSK3ß in yeast two-hybrid assays and co-immunoprecipitation. Molecular modeling showed that mammalian GSKIP could form a dimer through the L130 residue (GSK3ß binding site) rather than V41/L45 residues. In contrast, V41/L45P mutant facilitated a gain-of-function effect on GSKIP dimerization, further influencing binding behavior to GSK3ß compared to GSKIP wild-type (wt). The V41/L45 residues are not only responsible for PKA RII binding that controls GSK3ß activity, but also affect dimerization of GSKIP monomer, with net results of gain-of-function in GSKIP-GSK3ß interaction. In addition to its reported role in modulating Drp1, Ser637 phosphorylation caused mitochondrial elongation; we postulated that GSKIP might be involved in the Wnt signaling pathway as a scavenger to recruit GSK3ß away from the ß-catenin destruction complex and as a competitor to compete for GSK3ß binding, resulting in accumulation of S675 phosphorylated ß-catenin.