Actin-Dependent Mechanism of Tumor Progression Induced by a Dysfunction of p53 Tumor Suppressor.

Cancer cell aggressiveness, marked by actin cytoskeleton reconfiguration critical for metastasis, may result from an imbalanced ratio favoring γ-actin. Dysfunctional p53 emerges as a key regulator of invasiveness and migration in various cancer cells, both in vitro and in vivo. P53 inactivation (via mutants R175H, R248W, R273H, or TP53 repression) significantly enhanced the migration, invasion, and proliferation of human lung adenocarcinoma A549 cells in vitro and in vivo, facilitating intrapulmonary xenograft metastasis in athymic mice.

Establishment and Characterization of Multi-Drug Resistant p53-Negative Osteosarcoma SaOS-2 Subline.

Aim: To establish a p53-negative osteosarcoma (OS) SaOS-2 cellular subline exhibiting resistance to specific chemotherapeutic agents, including topoisomerase II inhibitors, taxanes, and vinca alkaloids.

Methods: The OS subline exhibiting resistance to the chemotherapeutic agents indicated above was generated by the stepwise treatment of the parental SaOS-2 cell line with increasing concentrations of doxorubicin (Dox) for 5 months. Half-inhibitory concentrations (IC) for Dox, vinblastine (Vin), and paclitaxel (PTX) were calculated by a colorimetric MTS-based assay.

The Design, Synthesis, and Biological Activities of Pyrrole-Based Carboxamides: The Novel Tubulin Inhibitors Targeting the Colchicine-Binding Site.

Microtubule targeting agents (MTAs) that interfere with the dynamic state of the mitotic spindle are well-known and effective chemotherapeutic agents. These agents interrupt the microtubule network via polymerization or depolymerization, halting the cell cycle progression and leading to apoptosis. We report two novel pyrrole-based carboxamides (CAs) (CA-61 and -84) as the compounds exhibiting potent anti-cancer properties against a broad spectrum of epithelial cancer cell lines, including breast, lung, and prostate cancer.

Inhibition of FGF2-Mediated Signaling in GIST-Promising Approach for Overcoming Resistance to Imatinib.

Inhibition of KIT-signaling is a major molecular target for gastrointestinal stromal tumor (GIST) therapy, and imatinib mesylate (IM) is known as the most effective first-line treatment option for patients with advanced, unresectable, and/or metastatic GISTs. We show here for the first time that the inhibition of KIT-signaling in GISTs induces profound changes in the cellular secretome, leading to the release of multiple chemokines, including FGF-2. IM increased migration, invasion, and colony formation of IM-resistant GISTs in an FGF2-dependent manner, whereas the use of blocking anti-FGF2 antibodies or BGJ398, a selective FGFR inhibitor, abolished these effects, thus suggesting that the activation of FGF2-mediated signaling could serve as a compensatory mechanism of KIT-signaling inhibited in GISTs.

Ethyl-2-amino-pyrrole-3-carboxylates are active against imatinib-resistant gastrointestinal stromal tumors in vitro and in vivo.

We showed recently that ethyl-2-amino-pyrrole-3-carboxylates (EAPCs) exhibit potent antiproliferative activities against a broad spectrum of soft tissue sarcoma and gastrointestinal stromal tumor (GIST) cell lines in vitro. The molecular mechanism of action was owing to inhibition of tubulin polymerization and induction of a robust G2/M cell-cycle arrest, leading to the accumulation of tumor cells in the M-phase and induction of apoptosis. Given that more than 50% of the patients with GISTs develop resistance to imatinib (IM) over the 2 years of IM-based therapy, we examined whether EAPCs exhibit activity against IM-resistant GISTs in vitro and in vivo.

Novel Predictors of Breast Cancer Survival Derived from miRNA Activity Analysis.

Breast cancer is among the leading causes of cancer-related death; discovery of novel prognostic markers is needed to improve outcomes. Combining systems biology and epidemiology, we investigated miRNA-associated genes and breast cancer survival in a well-characterized population-based study. A recently developed algorithm, , was used to identify key miRNA "activities" corresponding to target gene degradation, which were predictive of breast cancer mortality in published databases.

Sensitive genotyping of somatic mutations in the EGFR, KRAS, PIK3CA, BRAF genes from NSCLC patients using hydrogel biochips.

Targeted inhibitors of the epidermal growth factor receptor (EGFR) are used for the treatment of non-small cell lung cancer (NSCLC). Somatic mutations in the EGFR gene and key effectors of the EGFR-signaling pathway (KRAS, BRAF, PIK3CA) are associated with sensitivity to these drugs. We developed a highly sensitive LUNG CANCER (LC)-biochip approach for the detection of the most common EGFR, KRAS, PIK3CA, and BRAF gene mutations.

Immune selection of tumor cells in TCR β-chain transgenic mice.

The concept of immunological surveillance implies that immunogenic variants of tumor cells arising in the organism can be recognized by the immune system. Tumor progression is provided by somatic evolution of tumor cells under the pressure of the immune system. The loss of MHC Class I molecules on the surface of tumor cells is one of the most known outcomes of immune selection.

Comparisons of microRNA patterns in plasma before and after tumor removal reveal new biomarkers of lung squamous cell carcinoma.

Lung cancer is the major human malignancy, accounting for 30% of all cancer-related deaths worldwide. Poor survival of lung cancer patients, together with late diagnosis and resistance to classic chemotherapy, highlights the need for identification of new biomarkers for early detection. Among different cancer biomarkers, small non-coding RNAs called microRNAs (miRNAs) are considered the most promising, owing to their remarkable stability, their cancer-type specificity, and their presence in body fluids.

MHC restriction and allogeneic immune responses.

Discovery of major histocompatability complex (MHC) restriction helped in the understanding of how T-lymphocytes recognize antigens on bacteria, viruses, and tumor cells. It was initially accepted that MHC restriction was a consequence of "adaptive differentiation" in the thymus; during differentiation, the forming repertoire of T-lymphocytes "learned" a low affinity for self MHC molecules via positive selection. This view was later countered by discovery of artifacts in underlying studies and the fact that adaptive differentiation could not explain direct allogeneic and allorestricted recognition phenomena.

Lip, a human gene detected by transfection of DNA from a human liposarcoma encodes a protein with homology to regulators of small g proteins.

Purpose/Method. Transfection experiments have been used to identify activated oncogenes in a wide variety of tumour types. Here we describe the use of transfection experiments utilizing DNA from a human pleomorphic liposarcoma to identify a novel gene, designated lip which maps to chromosome 19.

Cyclophilin A produced by thymocytes regulates the migration of murine bone marrow cells.

Supernatant obtained from high dose hydrocortisone resistant thymocytes can induce migration of the bone marrow cell precursors to the periphery. This biological activity depends on the presence of the 18 kDa protein, whose amino acid sequence fits with the sequence of the secretory form of murine cyclophilin A (SP-18). Cyclophilin A isolated from the supernatant of the cortisone-resistant thymoma EL-4 shows its characteristic functional features as it demonstrates isomerase activity and binds with cyclosporine A.

Novel TP53 gene mutations in tumors of Russian patients with breast cancer detected using a new solid phase chemical cleavage of mismatch method and identified by sequencing.

Mutations in the tumor-suppressor p53 gene TP53 are frequent in most human cancers including breast cancer. A new solid phase chemical cleavage of mismatch method (CCM) allowed rapid and efficient screening and analysis of the TP53 gene in DNA samples extracted from tumors of 89 breast cancer patients. The novel CCM technique utilized silica beads and the potassium permanganate/tetraethylammonium chloride (KMnO(4)/TEAC) and hydroxylamine (NH(2)OH) reactions were performed sequentially in a single tube.

[Cloning of differentially expressed cDNA sequences involved in malignant transformation induced by benzo(a)pyrene metabolite dihydroxyepoxy benzo pyrene].

Objective: To clone differentially expressed cDNA sequences involved in malignant transformation induced by benzo(a)pyrene metabolite dihydroxyepoxy benzo pyrene (BPDE).

Method: The malignant transformation of human bronchial epithelial cell line 16HBE induced by BPDE in vitro was used as a model for comparing gene expression between the transformed cells and controls. cDNA representational difference analysis (cDNA-RDA) was performed to isolate differentially expressed cDNA fragment in transformed cells.

Interaction of linear homologous DNA duplexes via Holliday junction formation.

Interaction of linear homologous DNA duplexes by formation of Holliday junctions was revealed by electrophoresis and confirmed by electron microscopy. The phenomenon was demonstrated using a model of five purified PCR products of different size and sequence. The double-stranded structure of interacting DNA fragments was confirmed using several consecutive purifications, S1-nuclease analysis, and electron microscopy.

Amplification and Over-Expression of the MDM2 Gene in Human Soft Tissue Tumours.

Purpose. Amplification of genetic sequences on chromosome 12q13 is frequently found in soft tissue tumours. However, for the MDM2 gene, over-expression of the MDM2 protein has not always been shown to accompany gene amplification, raising the possibility that amplification of genetic sequences targets alternative genes on chromosome 12q13 for over-expression.

Peptides of a major histocompatibility complex class I (Kb) molecule cause prolongation of skin graft survival and induce specific down-regulatory T cells demonstrable in the mixed lymphocyte reaction.

Six individual peptides of the major histocompatibility complex (MHC) class I molecule H-2Kb were synthesized. Intravenous injection of peptide 6 into mice prolonged the survival of Kb (BL/6 or B10.MBR) skin grafts on allogeneic R101 and B10.

Fibroblasts regulate the migration of MCF7 mammary carcinoma cells in hydrated collagen gel.

We have defined a tissue culture method suitable to study cell-cell interactions in an environmental set close to in vivo conditions. It consists of heterotypic cell populations mixed together inside a collagen gel in a chamber slide for a period of up to 14 days. When the three-dimensional system is saturated, cells will start to move on the plastic surface as monolayers surrounding the gel, with a characteristic speed depending on cell type.

Special differentiation requirements of original and enriched secondary cytotoxic T lymphocyte precursors (pCTL-2 memory cell) specific for the class I histocompatibility molecule.

The in vivo-induced pCTL-2 cells of the L3T4- Lyt-2+ phenotype specific for the H-2Kb molecule are converted into effector CTLs in mixed lymphocyte culture (MLC) in the presence of heat-treated donor stimulators much more efficiently when the donor and recipient differ from each other, not only in the major histocompatibility complex (MHC) class I (H-2Kb) (anti-B10.MBR B10.AKM) but also in the MHC classes I + II, i.

Difference between antigen-binding receptor repertoires in effector cytotoxic T lymphocytes and their secondary precursors (memory cells) specific to H-2Kb.

The fine specificity of antigen-binding receptors was compared in pCTL-2 and secondary effector CTL (cytotoxic T lymphocytes) induced in vivo with the H-2Kb alloantigen in recombinant inbred mice. The lymphocyte preparations were enriched by elution from macrophage monolayers of various origins, including the donor (B6 strain), the H-2Kb mutant bm1, the H-2Kk allele B10.A(4R) and the recipient strain B10.