Synthesis, thermal and antitumour studies of Th(IV) complexes with furan-2-carboxaldehyde4-phenyl-3-thiosemicarbazone

Thorium(IV) complexes with the Schiff base furan-2-carboxaldehyde4-phenyl-3-thiosemicarbazone (L) were synthesised and characterized. The composition and structure of the metal complexes were proposed based on elemental analysis, molar conductivity measurements, FTIR and 1H-NMR spectroscopy. The Schiff base behaves as a neutral bidentate ligand coordinating through the azomethine N and the thioketo S atoms. From various studies, complexes were ascertained the general formula [ThL2X4] and [ThL2Y2], where X represents NO3–, NCS–, CH3COO–, CH3CHOHCOO–, ClO4– and Y SO42–and C2O42–. The thermal behaviour of the nitrato and oxalato complexes was studied and kinetic and thermodynamic parameters were calculated using the Coats-Redfern Equation. The ligand and a representative complex [ThL2(NO3)4] were screened in vitro for their antitumour activity against the human cervical cancer cell line (HeLa)

Nicotine-induced survival signaling in lung cancer cells is dependent on their p53 status while its down-regulation by curcumin is independent

<p>Abstract</p> <p>Background</p> <p>Lung cancer is the most lethal cancer and almost 90% of lung cancer is due to cigarette smoking. Even though nicotine, one of the major ingredients of cigarette smoke and the causative agent for addiction, is not a carcinogen by itself, several investigators have shown that nicotine can induce cell proliferation and angiogenesis. We observed that the proliferative index of nicotine is different in the lung cancer cell lines H1299 (p53-/-) and A549 (p53+/+) which indicates that the mode of up-regulation of survival signals by nicotine might be different in cells with and without p53.</p> <p>Results</p> <p>While low concentrations of nicotine induced activation of NF-κB, Akt, Bcl2, MAPKs, AP1 and IAPs in H1299, it failed to induce NF-κB in A549, and compared to H1299, almost 100 times higher concentration of nicotine was required to induce all other survival signals in A549. Transfection of WT-p53 and DN-p53 in H1299 and A549 respectively, reversed the mode of activation of survival signals. Curcumin down-regulated all the survival signals induced by nicotine in both the cells, irrespective of their p53 status. The hypothesis was confirmed when lower concentrations of nicotine induced NF-κB in two more lung cancer cells, Hop-92 and NCI-H522 with mutant p53 status. Silencing of p53 in A549 using siRNA made the cells susceptible to nicotine-induced NF-κB nuclear translocation as in A549 DN-p53 cells.</p> <p>Conclusions</p> <p>The present study reveals a detrimental role of nicotine especially in lung cancer patients with impaired p53 status and identifies curcumin as a potential chemopreventive.</p

CARP-1 Functional Mimetics Are a Novel Class of Small Molecule Inhibitors of Malignant Pleural Mesothelioma Cells

Malignant pleural mesothelioma (MPM) is an asbestos-related thoracic malignancy that is characterized by late metastases, and resistance to therapeutic modalities. The toxic side-effects of MPM therapies often limit their clinical effectiveness, thus necessitating development of new agents to effectively treat and manage this disease in clinic. CARP-1 functional mimetics (CFMs) are a novel class of compounds that inhibit growth of diverse cancer cell types. Here we investigated MPM cell growth suppression by the CFMs and the molecular mechanisms involved. CFM-1, -4, and -5 inhibited MPM cell growth, in vitro, in part by stimulating apoptosis. Apoptosis by CFM-4 involved activation of pro-apoptotic stress-activated protein kinases (SAPKs) p38 and JNK, elevated CARP-1 expression, cleavage of PARP1, and loss of the oncogene c-myc as well as mitotic cyclin B1. Treatments of MPM cells with CFM-4 resulted in depletion of NF-κB signaling inhibitor ABIN1 and Inhibitory κB (IκB)α and β, while increasing expression of pro-apoptotic death receptor (DR) 4 protein. CFM-4 enhanced expression of serine-phosphorylated podoplanin and cleavage of vimetin. CFMs also attenuated biological properties of the MPM cells by blocking their abilities to migrate, form colonies in suspension, and invade through the matrix-coated membranes. Both podoplanin and vimentin regulate processes of cell motility and invasion, and their expression often correlates with metastatic disease, and poor prognosis. The fact that phosphorylation of serines in the cytoplasmic domain of podoplanin interferes with processes of cellular motility, CFM-4-dependent elevated phosphorylated podoplanin and cleavage of vimentin underscore a metastasis inhibitory property of these compounds, and suggest that CFMs and/or their future analogs have potential as anti-MPM agents

Phosphorylation of cell cycle and apoptosis regulatory protein-1 by stress activated protein kinase P38γ is a novel mechanism of apoptosis signaling by genotoxic chemotherapy

CARP-1, a perinuclear phospho-protein, regulates cell survival and apoptosis signaling induced by genotoxic drugs. However, kinase(s) phosphorylating CARP-1 and down-stream signal transduction events remain unclear. Here we find that CARP-1 Serine (S)626 and Threonine (T)627 substitution to Alanines (AA) inhibits genotoxic drug-induced apoptosis. CARP-1 T627 is followed by a Proline (P), and this TP motif is conserved in vertebrates. Based on these findings, we generated affinity-purified, anti-phospho-CARP-1 T627 rabbit polyclonal antibodies, and utilized them to elucidate chemotherapy-activated, CARP-1-dependent cell growth signaling mechanisms. Our kinase profiling studies revealed that MAPKs/SAPKs phosphorylated CARP-1 T627. We then UV cross-linked protein extracts from Adriamycin-treated HeLa cervical cancer cells with a CARP-1 (614–638) peptide, and conducted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses of the peptide-bound protein complexes. This experiment revealed SAPK p38γ interaction with CARP-1 (614–638) peptide. Our studies further established that SAPK p38γ, but not other MAPKs, phosphorylates CARP-1 T627 in cancer cells treated with genotoxic drugs. Loss of p38γ abrogates CARP-1 T627 phosphorylation, and results in enhanced survival of breast cancer cells by genotoxic drugs. CARP-1 T627 phosphorylation was also noted in breast tumors from patients treated with radiation or endocrine therapies. We conclude that genotoxic drugs activate p38γ-dependent CARP-1 T627 phosphorylation to inhibit cell growth

A H2AX–CARP-1 Interaction Regulates Apoptosis Signaling Following DNA Damage

Cell Cycle and Apoptosis Regulatory Protein (CARP-1/CCAR1) is a peri-nuclear phosphoprotein that regulates apoptosis via chemotherapeutic Adriamycin (doxorubicin) and a novel class of CARP-1 functional mimetic (CFM) compounds. Although Adriamycin causes DNA damage, data from Comet assays revealed that CFM-4.16 also induced DNA damage. Phosphorylation of histone 2AX (γH2AX) protein is involved in regulating DNA damage repair and apoptosis signaling. Adriamycin or CFM-4.16 treatments inhibited cell growth and caused elevated CARP-1 and γH2AX in human breast (HBC) and cervical cancer (HeLa) cells. In fact, a robust nuclear or peri-nuclear co-localization of CARP-1 and γH2AX occurred in cells undergoing apoptosis. Knock-down of CARP-1 diminished γH2AX, their co-localization, and apoptosis in CFM-4.16- or Adriamycin-treated cells. We found that CARP-1 directly binds with H2AX, and H2AX interacted with CARP-1, but not CARP-1 (Δ600–652) mutant. Moreover, cells expressing CARP-1 (Δ600–652) mutant were resistant to apoptosis, and had diminished levels of γH2AX, when compared with cells expressing wild-type CARP-1. Mutagenesis studies revealed that H2AX residues 1–35 harbored a CARP-1-binding epitope, while CARP-1 amino acids 636–650 contained an H2AX-interacting epitope. Surface plasmon resonance studies revealed that CARP-1 (636–650) peptide bound with H2AX (1–35) peptide with a dissociation constant (Kd) of 127 nM. Cells expressing enhanced GFP (EGFP)-tagged H2AX (1–35) peptide or EGFP-tagged CARP-1 (636–650) peptide were resistant to inhibition by Adriamycin or CFM-4.16. Treatment of cells with transactivator of transcription (TAT)-tagged CARP-1 (636–650) peptide resulted in a moderate, statistically significant abrogation of Adriamycin-induced growth inhibition of cancer cells. Our studies provide evidence for requirement of CARP-1 interaction with H2AX in apoptosis signaling by Adriamycin and CFM compounds

Signaling defects and functional impairment in T-cells from cervical cancer patients

The ability of T-lymphocytes to recognize antigens and transduce signals to the nucleus successfully is a key component in the initiation and maintenance of an immune response. The present study addressed the expression status of the signal-transducing proteins in relation to the immune impairment in cervical cancer patients. Immune response was measured by evaluating lymphocyte subpopulations CD3+, CD4+, and CD8+, using flowcytometry, natural killer cell activity, using the single-cell cytotoxicity assay, lymphocyte function, using mitogenic response to PHA and T-cell activation following anti-CD3 stimulation, and production of IL-2. Expression of the T-cell signal transduction proteins, TCR-ζ, CD3-ɛ, zap-70, p56lck, PKC, NFκβ p50, Rel-A, Rel-B, and c-rel, was evaluated by using Western blot assay. A generalized depression of the immune response with respect to the different parameters evaluated was observed. Exogenous interleukin-2 (IL-2) could increase the response in all the controls and in 30% of the patients to different degrees varying from 10% to 90%. Low levels of the signaling molecules (TCR-ζ, CD3-ɛ, zap-70, p56lck, and PKC) and impairment in the transduction of NFκβ components (p50, Rel-A, Rel-B, and c-rel) to the nuclei were observed in these lymphocytes. Decreased CD4+/CD8+ ratio with an increase in suppressor cells, reduced lymphocyte proliferation, and production of IL-2 suggest a defective immune regulation in cervical cancer. Impairment in the translocation of NFκβ p50, Rel-A, and Rel-B to the nucleus and the reduced levels of signal-transducing proteins might be responsible for the decreased production of IL-2 and immune impairment in cervical cancer patients

Mechanisms of neuroblastoma cell growth inhibition by CARP-1 functional mimetics.

Neuroblastomas (NBs) are a clinically heterogeneous group of extra cranial pediatric tumors. Patients with high-risk, metastatic NBs have a long-term survival rate of below 40%, and are often resistant to current therapeutic modalities. Due to toxic side effects associated with radiation and chemotherapies, development of new agents is warranted to overcome resistance and effectively treat this disease in clinic. CARP-1 functional mimetics (CFMs) are an emerging class of small molecule compounds that inhibit growth of diverse cancer cell types. Here we investigated NB inhibitory potential of CFMs and the molecular mechanisms involved. CFM-1, -4, and -5 inhibited NB cell growth, in vitro, independent of their p53 and MYCN status. CFM-4 and -5 induced apoptosis in NB cells in part by activating pro-apoptotic stress-activated kinases (SAPKs) p38 and JNK, stimulating CARP-1 expression and cleavage of PARP1, while promoting loss of the oncogenes C and N-myc as well as mitotic cyclin B1. Treatments of NB cells with CFM-4 or -5 also resulted in loss of Inhibitory κB (IκB) α and β proteins. Micro-RNA profiling revealed upregulation of XIAP-targeting miR513a-3p in CFM-4-treated NB, mesothelioma, and breast cancer cells. Moreover, exposure of NB and breast cancer cells to CFM-4 or -5 resulted in diminished expression of anti-apoptotic XIAP1, cIAP1, and Survivin proteins. Expression of anti-miR513a-5p or miR513a-5p mimic, however, interfered with or enhanced, respectively, the breast cancer cell growth inhibition by CFM-4. CFMs also impacted biological properties of the NB cells by blocking their abilities to migrate, form colonies in suspension, and invade through the matrix-coated membranes. Our studies indicate anti-NB properties of CFM-4 and 5, and suggest that these CFMs and/or their future analogs have potential as anti-NB agents

Synthesis and preliminary evaluation of 2-substituted-1,3-benzoxazole and 3-[(3-substituted)propyl]-1,3-benzoxazol-2(3H)-one derivatives as potent anticancer agents

The synthesis and cytotoxic activity studies of a new series of cyclic amine containing benzoxazole and benzoxazolone derivatives are described. The 2-cyclic amine-1,3-benzoxazoles 5a-k, 5-chloro-3-(3-chloropropyl)-1,3-benzoxazol-2(3H)-one 8 and 3-[3-(cyclic amino)propyl]-1,3-benzoxazol-2(3H)-ones 9a-f were synthesized. The newly synthesized compounds with the influence of the presence of cyclic amine moiety in the benzoxazole scaffold have been evaluated with respect to their cytotoxic effect toward four human cancer cell lines. The new compounds were evaluated to see whether substitution at the second and third position of the benzoxazole motif influence their cytotoxic effect toward cancer cells