3D Disease Modelling of Hard and Soft Cancer Using PHA-Based Scaffolds.

Tumour cells are shown to change shape and lose polarity when they are cultured in 3D, a feature typically associated with tumour progression in vivo, thus making it significant to study cancer cells in an environment that mimics the in vivo milieu. In this study we established hard (MCF7 and MDA-MB-231, breast cancer) and soft (HCT116, colon cancer) 3D cancer tumour models utilizing a blend of P(3HO--3HD) and P(3HB). P(3HO--3HD) and P(3HB) belong to a group of natural biodegradable polyesters, PHAs, that are synthesised by microorganisms.

Oxygen-releasing manganese clay hybrid complex triggers p53-mediated cancer cell death in hypoxia.

Hypoxia in tumor microenvironment is responsible for resistance to conventional modes of cancer therapeutics. A manganese-clay hybrid compound MHC was shown to generate molecular oxygen in aqueous solution. In this study we have shown that MHC, in hypoxia, causes cancer cell death, through release of molecular oxygen and via p53-dependent apoptosis.

HIF-transcribed p53 chaperones HIF-1α.

Chronic hypoxia is associated with a variety of physiological conditions such as rheumatoid arthritis, ischemia/reperfusion injury, stroke, diabetic vasculopathy, epilepsy and cancer. At the molecular level, hypoxia manifests its effects via activation of HIF-dependent transcription. On the other hand, an important transcription factor p53, which controls a myriad of biological functions, is rendered transcriptionally inactive under hypoxic conditions.

Inhibition of apoptosis via CHIP-mediated proteasomal degradation of TAp73α.

TAp73, a homologous of tumor suppressor p53, regulates apoptosis in a p53-independent manner and its suppressive as well as stimulatory role in promoting angiogenesis has been reported. It exists in multiple isoforms which varies structurally in their N-terminus and C-terminus region and crucial interplay among them guides the decision of cell survival and death. As molecular chaperones control both stability and degradation of TAp73, selective regulation of p73 isoforms has implication upon developing new therapeutic for hypoxic tumor.

CHIP promotes autophagy-mediated degradation of aggregating mutant p53 in hypoxic conditions.

Tumor suppressor protein p53 aggregates in the hypoxic core of solid tumors. C terminus of Hsc70-interacting protein (CHIP) displays chaperone as well as E3 ligase activities in both stabilizing and degrading wild-type and mutant p53. In this study, we have discovered that CHIP selectively degrades aggregating mutant p53 under both normal and hypoxic conditions.

CHIP stabilizes amyloid precursor protein via proteasomal degradation and p53-mediated trans-repression of β-secretase.

In patient with Alzheimer's disease (AD), deposition of amyloid-beta Aβ, a proteolytic cleavage of amyloid precursor protein (APP) by β-secretase/BACE1, forms senile plaque in the brain. BACE1 activation is caused due to oxidative stresses and dysfunction of ubiquitin-proteasome system (UPS), which is linked to p53 inactivation. As partial suppression of BACE1 attenuates Aβ generation and AD-related pathology, it might be an ideal target for AD treatment.

p53's choice of myocardial death or survival: Oxygen protects infarct myocardium by recruiting p53 on NOS3 promoter through regulation of p53-Lys(118) acetylation.

Myocardial infarction, an irreversible cardiac tissue damage, involves progressive loss of cardiomyocytes due to p53-mediated apoptosis. Oxygenation is known to promote cardiac survival through activation of NOS3 gene. We hypothesized a dual role for p53, which, depending on oxygenation, can elicit apoptotic death signals or NOS3-mediated survival signals in the infarct heart.

p53 increases intra-cellular calcium release by transcriptional regulation of calcium channel TRPC6 in GaQ3-treated cancer cells.

p53 and calcium signaling are inter-dependent and are known to show both synergistic and antagonistic effects on each other in the cellular environment. However, no molecular mechanism or cellular pathway is known which shows direct regulation between these important cellular signaling molecules. Here we have shown that in cancer cells treated with anti-neoplastic drug GaQ3, p53, there is an increase in intracellular calcium levels by transcriptional regulation of a novel calcium channel gene TRPC6.

SCO2 induces p53-mediated apoptosis by Thr845 phosphorylation of ASK-1 and dissociation of the ASK-1-Trx complex.

p53 prevents cancer via cell cycle arrest, apoptosis, and the maintenance of genome stability. p53 also regulates energy-generating metabolic pathways such as oxidative phosphorylation (OXPHOS) and glycolysis via transcriptional regulation of SCO2 and TIGAR. SCO2, a cytochrome c oxidase assembly factor, is a metallochaperone which is involved in the biogenesis of cytochrome c oxidase subunit II.

p53 Ser15 phosphorylation disrupts the p53-RPA70 complex and induces RPA70-mediated DNA repair in hypoxia.

Cellular stressors are known to inhibit the p53-RPA70 (replication protein A, 70 kDa subunit) complex, and RPA70 increases cellular DNA repair in cancer cells. We hypothesized that regulation of RPA70-mediated DNA repair might be responsible for the inhibition of apoptosis in hypoxic tumours. We have shown that, in cancer cells, hypoxia disrupts the p53-RPA70 complex, thereby enhancing RPA70-mediated NER (nucleotide excision repair)/NHEJ (non-homologous end-joining) repair.

Regulation of glucose metabolism by p53: emerging new roles for the tumor suppressor.

p53 is well known as the "guardian of the genome" for differentiated and neoplastic cells. p53 induces cell-cycle arrest and cell death after DNA damage and thus contributes to the maintenance of genomic stability. In addition to this tumor suppressor function for pro-oncogenic cells, p53 also plays an important role as the central regulator of stress response by maintaining cellular homeostasis at the molecular and biochemical level.

Chaperoning of mutant p53 protein by wild-type p53 protein causes hypoxic tumor regression.

Mutant (Mt) p53 abrogates tumor suppression functions of wild-type (WT) p53 through mutant-specific, gain-of-function effects, and patients bearing Mt p53 are chemoresistant. The dominant negative effect of p53 mutants results from their aggregation propensity which causes co-aggregation of WT p53. We explored the mechanism of p53 inactivation in hypoxia and hypothesized whether WT p53 could rescue Mt p53 in hypoxic tumors.

Reactive oxygen species-mediated p53 core-domain modifications determine apoptotic or necrotic death in cancer cells.

Aims: p53 is known to induce apoptotic and necrotic cell death in response to stress, although the mechanism of these pathways is unknown. The aim of this study was to determine the molecular mechanism that determines p53's decision to select the apoptotic or necrotic mode of cell death.

Results: Gold nanoparticles (Au-NPs) induced both apoptosis and necrosis in cancer cells in a p53-dependent manner.

Gallium compound GaQ(3) -induced Ca(2+) signalling triggers p53-dependent and -independent apoptosis in cancer cells.

BACKGROUND AND PURPOSE A novel anti-neoplastic gallium complex GaQ(3) (KP46), earlier developed by us, is currently in phase I clinical trial. GaQ(3) induced S-phase arrest and apoptosis via caspase/PARP cleavage in a variety of cancers. However, the underlying mechanism of apoptosis is unknown.

Ultrastructural variations in platelets and platelet mitochondria: a novel feature in amyotrophic lateral sclerosis.

Platelets are characterized as a systemic tool to elucidate mitochondria-allied perturbance in neurological diseases. The authors studied ultrastructural changes in platelets and platelet mitochondria using a case-control approach in amyotrophic lateral sclerosis (ALS). Subjects were sporadic ALS cases (n = 22) and age- and sex-matched controls (n = 16).

Mitochondrial perturbance and execution of apoptosis in platelet mitochondria of patients with amyotrophic lateral sclerosis.

Role of platelets have been evinced as a systemic tool in a variety of neurological disorders. Oxidative phosphorylation contributes approximately 80% of total adenosine-tri-phosphate (ATP) production in resting platelets suggesting potential dependence of platelets on modest mitochondrial functioning. Since mitochondria play a pivotal role in regulating metabolic and apoptotic pathways in various neurodegenerative disorders including amyotrophic lateral sclerosis (ALS), we assessed mitochondrial membrane potential (MMP) associated alterations and apoptotic status of platelet mitochondria in ALS patients using case-control approach.

p53 Amino-terminus region (1-125) stabilizes and restores heat denatured p53 wild phenotype.

Background: The intrinsically disordered N-ter domain (NTD) of p53 encompasses approximately hundred amino acids that contain a transactivation domain (1-73) and a proline-rich domain (64-92) and is responsible for transactivation function and apoptosis. It also possesses an auto-inhibitory function as its removal results in remarkable reduction in dissociation of p53 from DNA.

Principal Findings/methodology: In this report, we have discovered that p53-NTD spanning amino acid residues 1-125 (NTD125) interacted with WT p53 and stabilized its wild type conformation under physiological and elevated temperatures, both in vitro and in cellular systems.

Stress response of a p53 homologue in the radioresistant Sf9 insect cells.

Purpose: To investigate homology and stress response of p53 (a 53 kDa tumor suppressor protein) orthologue in Sf9 Lepidopteran insect cell line that exhibits very high radioresistance.

Materials And Methods: Western immunoblotting, immunoprecipitation, degenerate RT-PCR (reverse transcription-polymerase chain reaction), electrophoretic gel mobility shift assay, flow cytometry and immuno-fluorescence microscopy were used for characterizing structural and functional features of Sfp53 (Spodoptera frugiperda p53) in gamma-irradiated or etoposide-treated Sf9 insect and BMG-1 (brain malignant glioma) human cells. Cells were pre-treated with caffeine for inhibiting ATM/ATR (ataxia-telangiectasia mutated protein/ATM and Rad-3-related protein) activation, wherever required.

Design, synthesis and characterization of some bioactive conjugates of curcumin with glycine, glutamic acid, valine and demethylenated piperic acid and study of their antimicrobial and antiproliferative properties.

The monoesters of curcumin, a symmetric diphenol with valine and glycine have been prepared by a novel solid phase synthesis and its diesters with valine, glutamic acid and demethylenated piperic acid have been prepared by solution phase method. The assessment of their antimicrobial and anticancer (antiproliferative) activities suggested that diesters of curcumin are relatively more active than curcumin itself due to their increased solubility, slow metabolism and better cellular uptake. Furthermore, significant observation was that monoesters of curcumin have even better antimicrobial activity than their corresponding diesters, emphasizing the role of free phenolic group.

CHIP chaperones wild type p53 tumor suppressor protein.

Wild type p53 exists in a constant state of equilibrium between wild type and mutant conformation and undergoes conformational changes at elevated temperature. We have demonstrated that the co-chaperone CHIP (carboxyl terminus of Hsp70-interacting protein), which suppressed aggregation of several misfolded substrates and induced the proteasomal degradation of both wild type and mutant p53, physically interacts with the amino terminus of WT53 and prevented it from irreversible thermal inactivation. CHIP preferentially binds to the p53 mutant phenotype and restored the DNA binding activity of heat-denatured p53 in an ATP-independent manner.

Telomerase targeted anticancer bioactive prodrug by antisense-based approach.

A deoxy 11-mer oligonucleotide 5'-GTTAGGGTTAG-3', complementary to a repeat sequence of human telomerase RNA template has been linked through phosphate and a C-2 linker to a bioactive tetraglycine conjugate of curcumin, a well-known antitumor herbal spice component of turmeric. This molecule has been transfected into KB and HeLa cell lines and found to affect cell growth in the former. This DNA-curcumin-tetraglycine acts as a prodrug being targeted by antisense mechanism to telomerase.

A proximal tissue-specific module and a distal negative regulatory module control apolipoprotein(a) gene transcription.

The apo(a) [apolipoprotein(a)] gene is responsible for variations in plasma lipoprotein(a), high levels of which are a risk factor for atherosclerosis and myocardial infarction. The apo(a) promoter stimulates the expression of reporter genes in HepG2 cells, but not in HeLa cells. In the present study, we demonstrate that the 1.

Multiple liver-specific factors bind to a 64-bp element and activate apo(a) gene.

The high plasma levels of lipoprotein(a) [Lp(a)] are associated with atherosclerosis. The apo(a) gene is responsible for the variance of Lp(a) concentration and its expression is liver-specific. By 5'-deletion analysis, we, in a luciferase gene reporter assay, have identified a 64-bp AT-rich region of upstream apo(a) gene (-703 to -640) that binds to multiple liver-specific factors.