MCL-1 interacts with MOF and BID to regulate H4K16 acetylation and homologous recombination repair.

The Participation of myeloid cell leukemia-1 (MCL-1), an antiapoptotic protein, in DNA repair and homologous recombination (HR) is not well understood. This study tests whether MCL-1 interacts with Males absent On First (MOF) to regulate H4K16 acetylation that promotes HR repair in response to replication stress induced by Hydroxyurea (HU) treatment. Co-immunoprecipitation of FLAG-MCL-1 from cancer cells treated with HU pulls down a complex of MCL-1, MOF and BH3-interacting domain death agonist (BID).

A Restriction Endonuclease-Based Assay to Distinguish NANOGP8 Retrogene from Parental NANOG.

NANOG is an embryonic transcription factor, which gets reexpressed in cancer stem or tumor initiating cells. NANOGP8, a retrogene belonging to the NANOG family, is predominantly expressed in cancer cells and shows very high similarity with NANOG both at the nucleotide and at the protein level. The high similarity makes it extremely challenging to distinguish between these two transcription factors.

Adenovirus and Oxaliplatin cooperate as agnostic sensitizers for immunogenic cell death in colorectal carcinoma.

Treatments with cytotoxic agents or viruses may cause Immunogenic Cell Death (ICD) that immunize tumor-bearing hosts but do not cause complete regression of tumor. We postulate that combining two ICD inducers may cause durable regression in immunocompetent mice. ICD was optimized in vitro by maximizing calreticulin externalization in human colorectal carcinoma (CRC) cells by exposure to mixtures of Oxaliplatin (OX) and human adenovirus (AdV).

Repurposing of mTOR Complex Inhibitors Attenuates MCL-1 and Sensitizes to PARP Inhibition.

MCL-1, a member of the antiapoptotic BCL-2 family, is a prosurvival protein with an essential DNA repair function. This study aims to test whether inhibition of protein synthesis by mTOR complex (mTORC) inhibitors depletes MCL-1, suppresses homologous recombination (HR) repair, and sensitizes cancer cells to PARP inhibitors. Treatment with everolimus decreases MCL-1 in colorectal carcinomas and small cell lung cancer (SCLC) cells but not glioblastoma multiforme (GBM) cells with a PTEN mutational background.

SMARCAD1 Phosphorylation and Ubiquitination Are Required for Resection during DNA Double-Strand Break Repair.

The chromatin remodeling factor SMARCAD1, an SWI/SNF ATPase family member, has a role in 5' end resection at DNA double-strand breaks (DSBs) to produce single-strand DNA (ssDNA), a critical step for subsequent checkpoint and repair factor loading to remove DNA damage. However, the mechanistic details of SMARCAD1 coupling to the DNA damage response and repair pathways remains unknown. Here we report that SMARCAD1 is recruited to DNA DSBs through an ATM-dependent process.

MCL-1 Depletion Impairs DNA Double-Strand Break Repair and Reinitiation of Stalled DNA Replication Forks.

Myeloid cell leukemia 1 (MCL-1) is a prosurvival BCL-2 protein family member highly expressed in hematopoietic stem cells (HSCs) and regulated by growth factor signals that manifest antiapoptotic activity. Here we report that depletion of MCL-1 but not its isoform MCL-1S increases genomic instability and cell sensitivity to ionizing radiation (IR)-induced death. MCL-1 association with genomic DNA increased postirradiation, and the protein colocalized with 53BP1 foci.

β2-spectrin depletion impairs DNA damage repair.

β2-Spectrin (β2SP/SPTBN1, gene SPTBN1) is a key TGF-β/SMAD3/4 adaptor and transcriptional cofactor that regulates TGF-β signaling and can contribute to liver cancer development. Here we report that cells deficient in β2-Spectrin (β2SP) are moderately sensitive to ionizing radiation (IR) and extremely sensitive to agents that cause interstrand cross-links (ICLs) or replication stress. In response to treatment with IR or ICL agents (formaldehyde, cisplatin, camptothecin, mitomycin), β2SP deficient cells displayed a higher frequency of cells with delayed γ-H2AX removal and a higher frequency of residual chromosome aberrations.

Inhibition of NANOG/NANOGP8 downregulates MCL-1 in colorectal cancer cells and enhances the therapeutic efficacy of BH3 mimetics.

Purpose: High levels of BCL-2 family members in colorectal carcinoma cause resistance to treatment. Inhibition of NANOG or its paralog NANOGP8 reduces the proliferation, stemness, and tumorigenicity of colorectal carcinoma cells. Our hypothesis was that inhibition of NANOG/NANOGP8 enhances the cytotoxic effect of BH3 mimetics targeting BCL-2 family members in colorectal carcinoma cells through reducing expression of MCL-1, a prosurvival BCL-2 protein.

Combination treatments with the PKC inhibitor, enzastaurin, enhance the cytotoxicity of the anti-mesothelin immunotoxin, SS1P.

Activated protein kinase C (PKC) contributes to tumor survival and proliferation, provoking the development of inhibitory agents as potential cancer therapeutics. Immunotoxins are antibody-based recombinant proteins that employ antibody fragments for cancer targeting and bacterial toxins as the cytotoxic agent. Pseudomonas exotoxin-based immunotoxins act via the ADP-ribosylation of EF2 leading to the enzymatic inhibition of protein synthesis.

Zinc regulates the activity of kinase-phosphatase pair (BasPrkC/BasPrpC) in Bacillus anthracis.

Bacillus anthracis Ser/Thr protein kinase PrkC (BasPrkC) is important for virulence of the bacterium within the host. Homologs of PrkC and its cognate phosphatase PrpC (BasPrpC) are the most conserved mediators of signaling events in diverse bacteria. BasPrkC homolog in Bacillus subtilis regulates critical processes like spore germination and BasPrpC modulates the activity of BasPrkC by dephosphorylation.

Combination treatments with ABT-263 and an immunotoxin produce synergistic killing of ABT-263-resistant small cell lung cancer cell lines.

Synergistic killing was achieved when Small Cell Lung Cancer (SCLC) cell lines were incubated with ABT-263 and an immunotoxin directed to the transferrin receptor. SCLC lines are variably sensitive to the BH-3 only peptide mimetic, ABT-263. To determine their sensitivity to toxin-based reagents, we incubated four representative SCLC lines with a model Pseudomonas exotoxin-based immunotoxin directed to the transferrin receptor.

Unveiling the novel dual specificity protein kinases in Bacillus anthracis: identification of the first prokaryotic dual specificity tyrosine phosphorylation-regulated kinase (DYRK)-like kinase.

Dual specificity protein kinases (DSPKs) are unique enzymes that can execute multiple functions in the cell, which are otherwise performed exclusively by serine/threonine and tyrosine protein kinases. In this study, we have characterized the protein kinases Bas2152 (PrkD) and Bas2037 (PrkG) from Bacillus anthracis. Transcriptional analyses of these kinases showed that they are expressed in all phases of growth.

Comparative genomic study of spo0E family genes and elucidation of the role of Spo0E in Bacillus anthracis.

The propensity of bacterium to sporulate or retain the vegetative form depends on the amount of phosphorylated Spo0A (Spo0A(-P)), regulated by Spo0E multigene family of phosphatases (Spo0E, YisI and YnzD). Phylogenetic analysis revealed that Spo0E multigene family of phosphatases (SMFP) descends in two distinct clades of aerobic (Bacillus cluster) and anaerobic (Clostridia cluster) sporulating bacteria. High sequence conservation within species gives a notion that these members could have evolved through lineage and species-specific duplication event.

Identification, characterization and activation mechanism of a tyrosine kinase of Bacillus anthracis.

Bacillus subtilis has three active tyrosine kinases, PtkA, PtkB and McsB, which play an important role in the physiology of the bacterium. Genome sequence analysis and biochemical experiments indicated that the ortholog of McsB, BAS0080, is the only active tyrosine kinase present in Bacillus anthracis. The autophosphorylation of McsB of B.

Spo0B of Bacillus anthracis - a protein with pleiotropic functions.

Spo0B is an important component of the phosphorelay signal transduction pathway, the pathway involved in the initiation of sporulation in Bacillus subtilis. Bioinformatic, phylogenetic and biochemical studies showed that Spo0B of Bacillus anthracis has evolved from citrate/malate kinases. During the course of evolution, Spo0B has retained the characteristic histidine kinase boxes H, N, F, G(1) and G(2), and has acquired nucleotide-binding domains, Walker A and Walker B, of ATPases.

Properties of Bacillus anthracis spores prepared under various environmental conditions.

Bacillus anthracis makes highly stable, heat-resistant spores which remain viable for decades. Effect of various stress conditions on sporulation in B. anthracis was studied in nutrient-deprived and sporulation medium adjusted to various pH and temperatures.

Proteome analysis of mouse macrophages treated with anthrax lethal toxin.

Anthrax toxin produced by Bacillus anthracis is a tripartite toxin comprising of protective antigen (PA), lethal factor (LF) and edema factor (EF). PA is the receptor-binding component, which facilitates the entry of LF or EF into the cytosol. EF is a calmodulin-dependent adenylate cyclase that causes edema whereas LF is a zinc metalloprotease and leads to necrosis of macrophages.