Addressing the Reciprocal Crosstalk between the AR and the PI3K/AKT/mTOR Signaling Pathways for Prostate Cancer Treatment.

The reduction in androgen synthesis and the blockade of the androgen receptor (AR) function by chemical castration and AR signaling inhibitors represent the main treatment lines for the initial stages of prostate cancer. Unfortunately, resistance mechanisms ultimately develop due to alterations in the AR pathway, such as gene amplification or mutations, and also the emergence of alternative pathways that render the tumor less or, more rarely, completely independent of androgen activation. An essential oncogenic axis activated in prostate cancer is the phosphatidylinositol-3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR) pathway, as evidenced by the frequent alterations of the negative regulator phosphatase and tensin homolog (PTEN) and by the activating mutations in PI3K subunits.

Discovery and Characterization of the Potent and Highly Selective 1,7-Naphthyridine-Based Inhibitors BAY-091 and BAY-297 of the Kinase PIP4K2A.

PIP4K2A is an insufficiently studied type II lipid kinase that catalyzes the conversion of phosphatidylinositol-5-phosphate (PI5P) into phosphatidylinositol 4,5-bisphosphate (PI4,5P). The involvement of PIP4K2A/B in cancer has been suggested, particularly in the context of p53 mutant/null tumors. PIP4K2A/B depletion has been shown to induce tumor growth inhibition, possibly due to hyperactivation of AKT and reactive oxygen species-mediated apoptosis.

The potent AMPK inhibitor BAY-3827 shows strong efficacy in androgen-dependent prostate cancer models.

Purpose: 5' adenosine monophosphate-activated kinase (AMPK) is an essential regulator of cellular energy homeostasis and has been associated with different pathologies, including cancer. Precisely defining the biological role of AMPK necessitates the availability of a potent and selective inhibitor.

Methods: High-throughput screening and chemical optimization were performed to identify a novel AMPK inhibitor.

Identification of Small Molecules that Modulate Mutant p53 Condensation.

Structural mutants of p53 induce global p53 protein destabilization and misfolding, followed by p53 protein aggregation. First evidence indicates that p53 can be part of protein condensates and that p53 aggregation potentially transitions through a condensate-like state. We show condensate-like states of fluorescently labeled structural mutant p53 in the nucleus of living cancer cells.

Ex vivo resistance in childhood acute lymphoblastic leukemia: Correlations between BCRP, MRP1, MRP4 and MRP5 ABC transporter expression and intracellular methotrexate polyglutamate accumulation.

Chemoresistance is an important factor in the treatment failure of childhood acute lymphoblastic leukemia (ALL). One underlying mechanism of chemoresistance involves (over)expression of ATP-dependent drug efflux transporters such as multidrug resistance protein 1-5 (MRP1-5) and breast cancer resistance protein (BCRP), which can extrude the important antileukemia drug methotrexate (MTX). Survival of childhood ALL critically depends on the leukemic blasts' capacity for intracellular retention of MTX and MTX-polyglutamates.

Discovery and Characterization of the Potent and Highly Selective (Piperidin-4-yl)pyrido[3,2- d]pyrimidine Based in Vitro Probe BAY-885 for the Kinase ERK5.

The availability of a chemical probe to study the role of a specific domain of a protein in a concentration- and time-dependent manner is of high value. Herein, we report the identification of a highly potent and selective ERK5 inhibitor BAY-885 by high-throughput screening and subsequent structure-based optimization. ERK5 is a key integrator of cellular signal transduction, and it has been shown to play a role in various cellular processes such as proliferation, differentiation, apoptosis, and cell survival.

MACC1 Induces Tumor Progression in Transgenic Mice and Colorectal Cancer Patients via Increased Pluripotency Markers Nanog and Oct4.

Purpose: We have previously identified the gene MACC1 as a strong prognostic biomarker for colorectal cancer metastasis and patient survival. Here, we report for the first time the generation of transgenic mouse models for MACC1.

Experimental Design: We generated mice with transgenic overexpression of MACC1 in the intestine driven by the villin promoter (vil-MACC1) and crossed them with Apc(Min) mice (vil-MACC1/Apc(Min)).

Anti-metastatic treatment in colorectal cancer: targeting signaling pathways.

Colorectal cancer is one of the most common cancers worldwide and one of the leading causes of cancer-related death in the Western world. Tumor progression towards metastasis affects a large number of patients with colorectal cancer and seriously affects their clinical outcome. Therefore, considerable effort has been made towards the development of therapeutic strategies that can decrease or prevent colorectal cancer metastasis.

Thiamine is a substrate of organic cation transporters in Caco-2 cells.

The aim of this study was to characterize the intestinal absorption of thiamine, by investigating the hypothesis of an involvement of Organic Cation Transporter (OCT) family members in this process. [(3)H]-T(+) uptake was found to be: 1) time-dependent, 2) Na(+)- and Cl(-)-dependent, 3) pH-dependent, with uptake increasing with a decrease in extracellular pH and decreasing with a decrease in intracellular pH, 4) inhibited by amiloride, 5) inhibited by the thiamine structural analogues oxythiamine and amprolium, 6) inhibited by the unrelated organic cations MPP(+), clonidine, dopamine, serotonin, 7) inhibited by the OCT inhibitors decynium22 and progesterone. Moreover, the dependence of [(3)H]-T(+) uptake on phosphorylation/dephosphorylation mechanisms was also investigated and [(3)H]-T(+) uptake was found to be reduced by PKA activation and protein tyrosine phosphatase and alkaline phosphatase inhibition.

S100A4-induced cell motility and metastasis is restricted by the Wnt/β-catenin pathway inhibitor calcimycin in colon cancer cells.

The calcium-binding protein S100A4 is a central mediator of metastasis formation in colon cancer. S100A4 is a target gene of the Wnt/β-catenin pathway, which is constitutively active in the majority of colon cancers. In this study a high-throughput screen was performed to identify small-molecule compounds targeting the S100A4-promoter activity.

Cytotoxicity studies of some novel fluoro acridone derivatives against sensitive and resistant cancer cell lines and their mechanistic studies.

A series of novel N(10)-substituted acridone derivatives bearing alkyl side-chain with tertiary amine groups at the terminal position were evaluated for their in vitro cytotoxic effects against drug sensitive and resistant cancer cell lines. All the molecules were designed on the basis of hydrogen bond acceptors, carbonyl, fluoro groups with precise spatial separation and structural features of lipophilicity, positive charge at neutral pH and presence of aromatic rings. The in vitro cytotoxic effects in comparison with reference drugs doxorubicin (DX) and C(1311) against cancer cell lines SW 1573, SW 1573 2R 160 (Pg-P expressing) which are non-small cell lung cancer cells, human embryo kidney cells HEK 293, HEK 293 MRP4, HEK 293 MRP5i, human promyelocytic leukemia sensitive cell line HL-60, including its multidrug cross-resistant of two main (P-gp and MRP) phenotype sublines vincristine resistant HL-60/VINC and doxorubicin resistant HL-60/DX cancer cell lines are presented.

Impact of ABCG2 polymorphisms on the clinical outcome and toxicity of gefitinib in non-small-cell lung cancer patients.

Aims: The current study investigates whether or not functional polymorphisms in the ATP-binding cassette transporter gene ABCG2 might affect gefitinib activity and/or toxicity in non-small-cell lung cancer (NSCLC) patients.

Materials & Methods: Towards this end, ABCG2 polymorphisms and expression were assessed in DNA and tumors from 94 NSCLC patients treated with gefitinib, whereas their associations with toxicity/response and time-to-progression/overall survival were evaluated using Pearson-χ(2) and log-rank-test, respectively.

Results: Patients carrying an ABCG2 -15622T/T genotype or harboring at least one TT copy in the ABCG2 (1143C/T, -15622C/T) haplotype developed significantly more grade 2/3 diarrhea (p < 0.

Synthesis of 2-fluoro N(10)-substituted acridones and their cytotoxicity studies in sensitive and resistant cancer cell lines and their DNA intercalation studies.

A series of 2-fluoro N(10)-substituted acridone derivatives with varying alkyl side chain length with propyl, butyl substitution, and a tertiary amine group at the terminal end of the alkyl side chain were synthesized and screened against cancer cell lines SW 1573, SW 1573 2R 160 (P-gp substrate) which are non-small lung cancer cell lines, MCF-7, MCF-7/MR (BCRP substrate) are breast cancer cell lines, 2008 WT, 2008MRP1, 2008MRP2, 2008MRP3 are ovarian cancer cell lines, and human embryo kidney cell lines like HEK293, HEK293 MRP4, and HEK293 MRP5i. The propyl-series compounds showed lipophilicity in the range of 1.93 to 4.

Intracellular trafficking of MDR transporters and relevance of SNPs.

Multi-drug resistance (MDR) frequently contributes to the failure of chemotherapeutic treatments in cancer patients. Mechanisms underlying the development of MDR have been extensively studied and are considered multifactorial. Among them, the ATP-Binding Cassette (ABC) family of proteins plays a pivotal role.

Molecular basis of bortezomib resistance: proteasome subunit beta5 (PSMB5) gene mutation and overexpression of PSMB5 protein.

The proteasome inhibitor bortezomib is a novel anticancer drug that has shown promise in the treatment of refractory multiple myeloma. However, its clinical efficacy has been hampered by the emergence of drug-resistance phenomena, the molecular basis of which remains elusive. Toward this end, we here developed high levels (45- to 129-fold) of acquired resistance to bortezomib in human myelomonocytic THP1 cells by exposure to stepwise increasing (2.

Molecular mechanisms underlying the synergistic interaction of erlotinib, an epidermal growth factor receptor tyrosine kinase inhibitor, with the multitargeted antifolate pemetrexed in non-small-cell lung cancer cells.

Because the epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor erlotinib and the multitargeted antifolate pemetrexed are registered in the treatment of second-line non-small-cell lung cancer (NSCLC), empirical combinations of these drugs are being tested. This study investigated molecular mechanisms underlying their combination in six NSCLC cell lines. Cells were characterized by heterogeneous expression of pemetrexed determinants, including thymidylate synthase (TS) and dihydrofolate reductase (DHFR), and mutations potentially affecting chemosensitivity.

Modulation of folate uptake in cultured human colon adenocarcinoma Caco-2 cells by dietary compounds.

Folate is a water-soluble B vitamin with a crucial role in the synthesis and methylation of DNA and in the metabolism of several amino acids. In the present study we investigated whether beverages like wine, beer and tea, or some of their specific constituents, affect the intestinal uptake of (3)H-folic acid or (3)H-methotrexate (an antifolate). All tested beverages significantly inhibited the uptake of (3)H-folic acid by Caco-2 cells.

Progesterone inhibits folic acid transport in human trophoblasts.

The aim of this work was to test the putative involvement of members of the ABC superfamily of transporters on folic acid (FA) cellular homeostasis in the human placenta. [(3)H]FA uptake and efflux in BeWo cells were unaffected or hardly affected by multidrug resistance 1 (MDR1) inhibition (with verapamil), multidrug resistance protein (MRP) inhibition (with probenecid) or breast cancer resistance protein (BCRP) inhibition (with fumitremorgin C). However, [(3)H]FA uptake and efflux were inhibited by progesterone (200 microM).

Acute and chronic effects of some dietary bioactive compounds on folic acid uptake and on the expression of folic acid transporters by the human trophoblast cell line BeWo.

Folic acid (FA) is a vitamin that acts as a coenzyme in the biosynthesis of purine and pyrimidine precursors of nucleic acids, which are critically important during pregnancy. Our group has previously shown that both reduced folate carrier (RFC1) and folate receptor alpha (FRalpha) seem to be involved in the uptake of [3H]folic acid ([3H]FA) by a human trophoblast cell line (BeWo) and by human primary cultured cytotrophoblasts. Our aim was to study the interaction between FA and some nutrients/bioactive substances.

Comparison of folic acid uptake characteristics by human placental choriocarcinoma cells at acidic and physiological pH.

The aim of this work was to characterize the placental uptake of folic acid from the maternal circulation. Using 2 human trophoblast cell lines (BeWo and JAR), we verified that uptake of 3H-folic acid was pH-dependent, increasing significantly with decreasing extracellular pH. In BeWo cells, uptake of 3H-folic acid at pH 5.

Characteristics of thiamine uptake by the BeWo human trophoblast cell line.

Little is known concerning the mechanisms responsible for the transplacental transfer of thiamine. So, the aim of this work was to characterize the placental uptake of thiamine from the maternal circulation, by determining the characteristics of 3H-thiamine uptake by a human trophoblast cell line (BeWo). Uptake of (3)H-thiamine (50-100 nM) by BeWo cells was: 1) temperature-dependent and energy-independent; 2) pH-dependent (uptake increased as the extracellular medium pH decreased); 3) Na(+)-dependent and Cl(-)-independent; 4) not inhibited by the thiamine structural analogs amprolium, oxythiamine and thiamine pyrophosphate; 5) inhibited by the unrelated organic cations guanidine, N-methylnicotinamide, tetraethylammonium, clonidine and cimetidine; 6) inhibited by the organic cation serotonin, and by two selective inhibitors of the serotonin plasmalemmal transporter (hSERT), fluoxetine and desipramine.

Effect of red wine on the intestinal absorption of thiamine and folate in the rat: comparison with the effect of ethanol alone.

Background: This work aimed to investigate, in the rat, the acute in vitro effect of red wine and the effect of chronic red wine ingestion on the intestinal absorption of thiamine and folate and to compare them with the effects of ethanol alone.

Methods: The effects of red wine and of an ethanol solution (same ethanol concentration as that in the red wine, i.e.