Fibroblast Growth Factor 2 (FGF2) Activates Vascular Endothelial Growth Factor (VEGF) Signaling in Gastrointestinal Stromal Tumors (GIST): An Autocrine Mechanism Contributing to Imatinib Mesylate (IM) Resistance.

We showed previously that the autocrine activation of the FGFR-mediated pathway in GIST lacking secondary mutations was a result of the inhibition of KIT signaling. We show here that the FGF2/FGFR pathway regulates VEGF-A/VEGFR signaling in IM-resistant GIST cells. Indeed, recombinant FGF2 increased the production of VEGF-A by IM-naive and resistant GIST cells.

Imbalance between Actin Isoforms Contributes to Tumour Progression in Taxol-Resistant Triple-Negative Breast Cancer Cells.

The widespread occurrence of breast cancer and its propensity to develop drug resistance highlight the need for a comprehensive understanding of the molecular mechanisms involved. This study investigates the intricate pathways associated with secondary resistance to taxol in triple-negative breast cancer (TNBC) cells, with a particular focus on the changes observed in the cytoplasmic actin isoforms. By studying a taxol-resistant TNBC cell line, we revealed a shift between actin isoforms towards γ-actin predominance, accompanied by increased motility and invasive properties.

Leaf Extract from European Olive (Olea europaea L.) Post-Transcriptionally Suppresses the Epithelial-Mesenchymal Transition and Sensitizes Gastric Cancer Cells to Chemotherapy.

The overall survival of patients with the advanced and recurrent gastric cancer (GC) remains unfavorable. In particular, this is due to cancer spreading and resistance to chemotherapy associated with the epithelial-mesenchymal transition (EMT) of tumor cells. EMT can be identified by the transcriptome profiling of GC for EMT markers.

Unraveling the Mechanism of Platelet Aggregation Suppression by Thioterpenoids: Molecular Docking and In Vivo Antiaggregant Activity.

Natural monoterpenes and their derivatives are widely considered the effective ingredients for the design and production of novel biologically active compounds. In this study, by using the molecular docking technique, we examined the effects of two series of "sulfide-sulfoxide-sulfone" thioterpenoids containing different (e.g.

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.

2-Amino-Pyrrole-Carboxylate Attenuates Homology-Mediated DNA Repair and Sensitizes Cancer Cells to Doxorubicin.

Despite a high efficacy of chemotherapy in cancer treatment, acquired resistance of tumors to certain chemotherapeutic agents and frequent side effects remain the major factors of unfavorable prognosis in most cancer patients with unresectable, metastatic and recurrent forms of the disease. The discovery of novel molecular targets in tumors and development of new therapeutic approaches to enhance the efficiency of chemotherapeutic agents remain the biggest challenges in current oncology. Here we examined the ability of pyrrole-based heterocyclic compound 2-APC to sensitize tumor cells to the topoisomerase II inhibitor doxorubicin.

Computational-Based Discovery of the Anti-Cancer Activities of Pyrrole-Based Compounds Targeting the Colchicine-Binding Site of Tubulin.

Despite the tubulin-binding agents (TBAs) that are widely used in the clinic for cancer therapy, tumor resistance to TBAs (both inherited and acquired) significantly impairs their effectiveness, thereby decreasing overall survival (OS) and progression-free survival (PFS) rates, especially for the patients with metastatic, recurrent, and unresectable forms of the disease. Therefore, the development of novel effective drugs interfering with the microtubules' dynamic state remains a big challenge in current oncology. We report here about the novel ethyl 2-amino-1-(furan-2-carboxamido)-5-(2-aryl/tert-butyl-2-oxoethylidene)-4-oxo-4,5-dihydro-1H-pyrrole-3-carboxylates (EAPCs) exhibiting potent anti-cancer activities against the breast and lung cancer cell lines in vitro.

Infigratinib (BGJ 398), a Pan-FGFR Inhibitor, Targets P-Glycoprotein and Increases Chemotherapeutic-Induced Mortality of Multidrug-Resistant Tumor Cells.

The microtubule-targeting agents (MTAs) are well-known chemotherapeutic agents commonly used for therapy of a broad spectrum of human malignancies, exhibiting epithelial origin, including breast, lung, and prostate cancer. Despite the impressive response rates shortly after initiation of MTA-based therapy, the vast majority of human malignancies develop resistance to MTAs due to the different mechanisms. Here, we report that infigratinib (BGJ 398), a potent FGFR1-4 inhibitor, restores sensitivity of a broad spectrum of ABCB1-overexpressing cancer cells to certain chemotherapeutic agents, including paclitaxel (PTX) and doxorubicin (Dox).

Unraveling the Mechanism of Platelet Aggregation Suppression by Monoterpenoids.

Platelet aggregation causes various diseases and therefore challenges the development of novel antiaggregatory drugs. In this study, we report the possible mechanism of platelet aggregation suppression by newly synthesized myrtenol-derived monoterpenoids carrying different heteroatoms (sulphur, oxygen, or nitrogen). Despite all tested compounds suppressed the platelet aggregation in vitro, the most significant effect was observed for the S-containing compounds.

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.

2-APCAs, the Novel Microtubule Targeting Agents Active Against Distinct Cancer Cell Lines.

Microtubules are known as the most attractive molecular targets for anti-cancer drugs. However, the number of serious limitations of the microtubule targeting agents (MTAs) including poor bioavailability, adverse effects (e.g.

Inhibition of AKT-Signaling Sensitizes Soft Tissue Sarcomas (STS) and Gastrointestinal Stromal Tumors (GIST) to Doxorubicin via Targeting of Homology-Mediated DNA Repair.

Activation of the phosphoinositide 3-kinase (PI3K)/Akt/mTOR pathway is well documented for a broad spectrum of human malignancies supporting their growth and progression. Accumulating evidence has also implicated AKT as a potent modulator of anti-cancer therapies via regulation of DNA damage response and repair (DDR) induced by certain chemotherapeutic agents and ionizing radiation (IR). In the present study, we examined the role of AKT signaling in regulating of Rad51 turnover and cytotoxic effects of topoisomerase II inhibitor, doxorubicin (Dox) in soft tissue sarcomas (STS) and gastrointestinal stromal tumors (GIST) in vitro.

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.

Targeting of FGF-Signaling Re-Sensitizes Gastrointestinal Stromal Tumors (GIST) to Imatinib In Vitro and In Vivo.

Dysregulation of the fibroblast growth factor (FGF)/fibroblast growth factor receptor (FGFR) signaling pathway is frequently observed in multiple human malignancies, and thus, therapeutic strategies targeting FGFs and FGFRs in human cancer are being extensively explored. We observed the activation of the FGF/FGFR-signaling pathway in imatinib (IM)-resistant gastrointestinal stromal tumor (GIST) cells. Furthermore, we found that the activation of FGFR signaling has a significant impact on IM resistance in GISTs in vitro.

Inhibition of fibroblast growth factor receptor-signaling sensitizes imatinib-resistant gastrointestinal stromal tumors to low doses of topoisomerase II inhibitors.

The acquired resistance of gastrointestinal stromal tumors (GISTs) to the targeted-based therapy remains the driving force to identify the novel approaches that are capable of increasing the sensitivity of GISTs to the current therapeutic regimens. Our present data show that BGJ398, a selective fibroblast growth factor receptor (FGFR) inhibitor, sensitizes imatinib (IM)-resistant GIST cells with receptor tyrosine kinase (RTK) switch (loss of c-KIT/gain of pFGFR2a) to the low doses of topoisomerase II inhibitors - doxorubicin (Dox) and etoposide (Eto). Mechanistically, pretreatment of IM-resistant GIST cells with BGJ398 for 12 h markedly enhanced proapoptotic and growth-suppressive effects of Dox (or Eto).

A Novel Receptor Tyrosine Kinase Switch Promotes Gastrointestinal Stromal Tumor Drug Resistance.

The fact that most gastrointestinal stromal tumors (GISTs) acquire resistance to imatinib (IM)-based targeted therapy remains the main driving force to identify novel molecular targets that are capable to increase GISTs sensitivity to the current therapeutic regimens. Secondary resistance to IM in GISTs typically occurs due to several mechanisms that include hemi- or homo-zygous deletion of the wild-type KIT allele, overexpression of focal adhesion kinase (FAK) and insulin-like growth factor receptor I (IGF-1R) amplification, BRAF mutation, a RTK switch (loss of c-KIT and gain of c-MET/AXL), etc. We established and characterized the IM-resistant GIST T-1 cell line (GIST T-1R) lacking secondary c-KIT mutations typical for the IM-resistant phenotype.

Establishment and characterization of a triple negative basal-like breast cancer cell line with multi-drug resistance.

Triple-negative breast carcinoma (TNBC) is one of the most aggressive subtypes of breast cancer and is associated with an unfavorable prognosis. The management of TNBC is currently based on the use of classical cytotoxic drugs, i.e.

Ethyl-2-amino-pyrrole-3-carboxylates are novel potent anticancer agents that affect tubulin polymerization, induce G2/M cell-cycle arrest, and effectively inhibit soft tissue cancer cell growth in vitro.

Microtubules are known to be one of the most attractive and validated targets in cancer therapy. However, the clinical use of drugs that affect the dynamic state of microtubules has been hindered by chemoresistance and toxicity issues. Accordingly, the development of novel agents that target microtubules is needed.

[3-Hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones induce the mitotic exit failure and cell death in tumor cells in vitro].

Some compound refering to the 3-hydroxy-1,5-diaryl-4-pivaloyl-2,5-dihydro-2-pyrrolones have been found to cause an increase in the number of mitotic cells and their subsequent death in vitro. This increased in the number of mitotic cells was not associated with increased cellular proliferative activity and was likely due to mitotic exit failure. Of note, the effect was more pronounced in the tumor cells when compared to human fibroblasts.