Heat shock protein-mediated protection against Cisplatin-induced hair cell death.

Cisplatin is a highly successful and widely used chemotherapy for the treatment of various solid malignancies in both adult and pediatric patients. Side effects of cisplatin treatment include nephrotoxicity and ototoxicity. Cisplatin ototoxicity results from damage to and death of cells in the inner ear, including sensory hair cells.

A novel tumor suppressor function of glycine N-methyltransferase is independent of its catalytic activity but requires nuclear localization.

Glycine N-methyltransferase (GNMT), an abundant cytosolic enzyme, catalyzes the transfer of a methyl group from S-adenosylmethionine (SAM) to glycine generating S-adenosylhomocysteine and sarcosine (N-methylglycine). This reaction is regulated by 5-methyltetrahydrofolate, which inhibits the enzyme catalysis. In the present study, we observed that GNMT is strongly down regulated in human cancers and is undetectable in cancer cell lines while the transient expression of the protein in cancer cells induces apoptosis and results in the activation of ERK1/2 as an early pro-survival response.

Inner ear supporting cells protect hair cells by secreting HSP70.

Mechanosensory hair cells are the receptor cells of hearing and balance. Hair cells are sensitive to death from exposure to therapeutic drugs with ototoxic side effects, including aminoglycoside antibiotics and cisplatin. We recently showed that the induction of heat shock protein 70 (HSP70) inhibits ototoxic drug-induced hair cell death.

The bradykinin B(2) receptor induces multiple cellular responses leading to the proliferation of human renal carcinoma cell lines.

Background: The vasoactive peptide bradykinin (BK) acts as a potent growth factor for normal kidney cells, but there have been few studies on the role of BK in renal cell carcinomas.

Purpose: In this study, we tested the hypothesis that BK also acts as a mitogen in kidney carcinomas, and explored the effects of BK in human renal carcinoma A498 cells.

Methods: The presence of mRNAs for BK B(1) and BK B(2) receptors in A498 cells was demonstrated by reverse transcription-polymerase chain reaction.

Celastrol inhibits aminoglycoside-induced ototoxicity via heat shock protein 32.

Hearing loss is often caused by death of the mechanosensory hair cells of the inner ear. Hair cells are susceptible to death caused by aging, noise trauma, and ototoxic drugs, including the aminoglycoside antibiotics and the antineoplastic agent cisplatin. Ototoxic drugs result in permanent hearing loss for over 500,000 Americans annually.

Role of integrins in angiotensin II-induced proliferation of vascular smooth muscle cells.

Angiotensin II (AII) binds to G protein-coupled receptor AT(1) and stimulates extracellular signal-regulated kinase (ERK), leading to vascular smooth muscle cells (VSMC) proliferation. Proliferation of mammalian cells is tightly regulated by adhesion to the extracellular matrix, which occurs via integrins. To study cross-talk between G protein-coupled receptor- and integrin-induced signaling, we hypothesized that integrins are involved in AII-induced proliferation of VSMC.

Bradykinin B2 receptor interacts with integrin alpha5beta1 to transactivate epidermal growth factor receptor in kidney cells.

We have shown previously that the vasoactive peptide bradykinin (BK) stimulates proliferation of a cultured murine cell model of the inner medullary collecting duct (mIMCD-3 cells) via transactivation of epidermal growth factor receptor (EGFR) by a mechanism that involves matrix metalloproteinases (collagenase-2 and -3). Because collagenases lack an integral membrane domain, we hypothesized that receptors for extracellular matrix proteins, integrins, may play a role in BK-induced signaling by targeting collagenases to the membrane, thus forming a functional signaling complex. BK-induced phosphorylation of extracellular signal-regulated protein kinase (ERK) in mIMCD-3 cells was reduced by approximately 65% by synthetic peptides containing an Arg-Gly-Asp sequence, supporting roles for integrins in BK-induced signaling.

Identification of functional bradykinin B(2) receptors endogenously expressed in HEK293 cells.

The human embryonic kidney (HEK) 293 cell line is widely used in cell biology research. Although HEK293 cells have been meticulously studied, our knowledge about endogenous G protein-coupled receptors (GPCR) in these cells is incomplete. While studying the effects of bradykinin (BK), a potent growth factor for renal cells, we unexpectedly discovered that BK activates extracellular signal-regulated protein kinase 1 and 2 (ERK) in HEK293 cells.

[Methylnitrosourea as challenge mutagen in assessment of the DNA mismatch repair (MMR) activity: association with some types of cancer].

Total repair capability is a widely used phenotypic marker of predisposition to cancer. Evaluation of this parameter implies using a challenge mutagen in an in vitro system to unmask latent genetic instability and repair insufficiency in the target cells. Traditionally, these investigations involve two tests, evaluation of mutagenic susceptibility (chromosomal aberrations) and genotoxic effect (DNA comet assay).

[Mismatch repair (MMR) efficiency and MSH2 gene mutation in human colorectal carcinoma cell line COLO320HSR].

Colorectal cancer (CC) is one of two diseases, in which the link between cancer proneness and DNA repair deficiency appears to be proved. A strict relationship between mismatch repair (MMR) gene mutations, microsatellite instability (MSI) has been found in familiar colorectal cancer (Lynch syndrome). Tumorigenesis at familiar cancer is initiated by biallelic mutations in the major MMR genes, namely MSH2 or MLH1.

Sensitivity of human lymphocytes to genotoxic effect of n-methyl-n-nitrosourea: possible relation to gynecological cancers.

Unlabelled: The aim of this work is to study responses of PHA-stimulated and resting lymphocytes to methylating agent N-methyl-N-nitrosourea (MNU) and to compare sensitivity to this agent of healthy donor lymphocytes and lymphocytes from patients with gynecological cancers.

Methods: Cytotoxicity of MNU, apoptotic death of lymphocytes, was evaluated using two common tests--annexin V-FITC detection assay and live/dead double staining assay (nuclear morphological changes). Genotoxic effect of the agent was determined as delayed (secondary) DNA double strand breaks (DSBs) using neutral comet assay both conventional variant and modified for detection of bromodeoxyuridine-labelled comets, produced by proliferating lymphocytes only.

[Comparison of geno- and cytotoxicity of methylnitrosourea on MMR-proficient and MMR-deficient human tumor cell lines].

Deficient mismatch repair (MMR) is identified as a mutation of one of four major MMR genes and(or) microsatellite instability. These genomic changes are used as markers of MMR status of the heredity nonpolyposis colorectal cancer (HNPCC) spectrum tumors--familial and sporadic tumors of colon and extracolonic cancers fulfilling Amsterdam clinical criteria II. MMR-deficiency results in mutator phenotype and resistance to geno- and cytotoxicity of alkylating agents.

[Hyperthermia induced signal for apoptosis and pathways of its transduction in the cell].

Hyperthermia (HT) is a physiological agent able to induce apoptosis in normal and tumor cells. The ability of HT to damage different cellular components is underlying the mechanism of apoptogenic activity of HT. The review is aimed to consider the studies representing mainly HT production of genotoxic initial signal and pathways of its transduction to programmed cytotoxic event or apoptosis.

Role of excision mechanisms of DNA repair in induction of apoptosis.

DNA repair and apoptosis lead to principally different final results: the first mechanism removes damages from DNA, restoring genome integrity; the second mechanism eliminates potentially dangerous cells harboring DNA lesions. The cells deficient in mismatch repair (MMR) demonstrate increased resistance (viability) to DNA-damaging agents due to decreased ability to undergo apoptosis. This means that mechanism of MMR both restores structure of DNA and generates a signal for apoptosis.