Apoptosis-inducing, anti-angiogenic and anti-migratory effects of a dinuclear Pd(II) complex on breast cancer: A promising novel compound.

Because of the high mortality and morbidity rate of breast cancer, successful management of the disease requires synthesis of novel compounds. To this end, ongoing attempts to create new candidates include synthesis of multinuclear metal complexes. The high DNA binding affinity and cytotoxic activity of these complexes makes them promising as breast cancer treatments. This study investigated anti-growth/cytotoxic effect of the dinuclear Pd(II) complex on breast cancer cell lines (MCF-7, MDA-MB-231) using various methods of staining, flow cytometry, and immunoblotting. The study conducted colony formation, invasion, and migration assays were to assess the effect of the complex on metastasis. Increased caspase-3/7 levels and positive annexin V staining were observed in both cell lines, proving apoptosis. Altered TNFR1 and TRADD expression with caspase-8 cleavage followed by BCL-2 inactivation with loss of mitochondrial membrane potential confirmed the presence of apoptosis in MCF-7 and MDA-MB-231, regardless of p53 expression status. The results implied anti-migration properties. Finally, the study used the CAM assay to assess antiangiogenic properties and showed that the complex inhibited angiogenesis. The study concluded the dinuclear Pd(II) complex warrants further in vivo experiments to show its potential in the treatment of breast cancer.

The Inhibition Mechanism of Pancreatic Ductal Adenocarcinoma via LXR Receptors: A Multifaceted Approach Integrating Molecular Docking, Molecular Dynamics and Post-MD Inter-Molecular Contact Analysis.

OBJECTIVE: Pancreatic ductal adenocarcinoma (PDAC) has an unfavorable outlook due to its aggressive characteristics, delayed diagnosis, and limited effective treatment options for advanced stages of the disease. The significant mortality rate has prompted investigations into additional factors that could aid in managing this type of cancer. Liver X receptors, specifically LXRα and LXRß, are nuclear receptors that oversee the expression of genes related to cholesterol, glucose, lipid metabolism, and inflammatory responses. LXRs have also emerged as potential targets for addressing PDAC, and recent findings have demonstrated that LXR ligands can impede cell proliferation in various cancer forms, notably pancreatic cancer. This comprehensive computational research study involving oncological in silico mechanism discovery explored inhibitory ligands for Liver X receptors (LXRα and LXRß), which are believed to have prognostic significance in PDAC. METHODS: The study utilized Baicalein, Beta-Sitosterol, Polydatin ligands in molecular docking and dynamics and post-molecular Hydrogen bonding contact analyses dynamics to characterize receptor inhibition. RESULT: The outcomes suggest that Baicalein exhibits versatile inhibitory effects on both receptors, while Beta-Sitosterol emerges as a highly effective inhibitor of LXRß. CONCLUSION: Further in vitro and in vivo investigations will be beneficial and would shed light onto the mechanism to decipher the suppression of PDAC evaluating the potential of Baicalein, Beta-Sitosterol, Polydatin natural ligand compounds.

Targeting of Notch, IL-1, and leptin has therapeutic potential in xenograft colorectal cancer.

Background/aim: Colorectal cancer (CRC) is a fatal malignancy type and its occurence still needs to be explored mechanistically. Notch, IL-1, and leptin crosstalk is reported to play a role in the proliferation, migration, and expression of proangiogenic molecules. In this study, we aimed to investigate the effect of inhibition of Notch, IL-1, and leptin on CRC. Materials and methods: To generate colorectal cancer tumor xenografts, 1 × 107 cells from exponentially growing cultures of HCT-15 cells were injected subcutaneously, at the axillary region of the left and right rear flanks of forty NOD.CB17-Prkdcscid/J (NOD/SCID) female mice. The mice were then monitored for the development of tumors and were randomly divided into five groups when tumor sizes reached a volume of approximately 150 mm3. Mice were used to determine the effectiveness of the gamma-secretase inhibitor (DAPT, Notch inhibitor), the interleukin-1 receptor antagonist (Anakinra) and the leptin receptor antagonist (Allo aca) against tumor growth. The mice were euthanized by CO2 inhalation immediately after the treatments finished, and all efforts were made to minimize suffering. Tumors were excissed for RT-PCR and histological analysis. Results: There is an intact Notch, IL-1, and leptin signaling axis, and in vivo antagonism of Notch, IL-1, and leptin affects mRNA and protein expression of inflammatory and angiogenic molecules. Conclusion: Present data suggest that targeting Notch, IL-1, and leptin may be possesses therapeutic potential in CRC.

Soloxolone methyl induces apoptosis and oxidative/ER stress in breast cancer cells and target cancer stem cell population.

One of the most prevalent malignancies in women and one of the leading causes of cancer-related death is breast cancer. There is a need for new treatment approaches and drugs for breast cancer. Many studies show the high potential of triterpene compounds and their semisynthetic derivatives as anticancer agents due to their ability to induce apoptosis and suppress tumorigenesis. The effects of soloxolone methyl (SM), a semisynthetic derivative of 18-H-glycyrrhetinic acid, on the cytotoxicity and apoptosis of human breast cancer cell line (T-47D) and cancer stem cell (CSCs) population (mammospheres; CD44+/CD24-antigen) derived from breast cancer cells, were examined in this work. The ATP assay was used to determine SM growth-inhibitory effects. Fluorescent staining, caspase-cleaved cytokeratin 18, and flow cytometry analysis were used to determine the mode of the cell death. In addition, cell death was investigated at protein and gene levels by Western Blotting and PCR, respectively. SM resulted in cytotoxicity in a time and dose dependent manner via ROS production and ER stress in T-47D cells in 2 models. The mode of cell death was apoptosis, evidenced by phosphatidylserine exposure, caspase activation, and bax overexpression. In mammospheres as 3D model, SM decreased stem cell properties and induced cell death. Taken together, SM may be a promising agent in the treatment of breast cancer, especially due to its antigrowth activity on CSCs.

Water-soluble copper(II) 5-fluorouracil complexes bearing polypyridyl co-ligands: synthesis, structures and anticancer activity.

Five newly synthesized copper(II) 5-fluorouracil (5-FU) complexes of polypyridyl co-ligands with good solubility in water, namely [CuCl(5-FU)(bpy)(DMSO)] (1), [Cu(5-FU)(phen)2](5-FU)·4H2O (2), [Cu(5-FU)(dpya)2](NO3)·2.5H2O (3), [Cu(5-FU)(NO3)(bpyma)]·H2O (4) and [CuCl(5-FU)(terpy)] (5) (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, dpya = 2,2'-dipyridylamine, bpyma = bis(2-pyridylmethyl)amine and terpy = 2,2';6',2''-terpyridine), were characterized by elemental analysis and a number of spectrometric methods. The structures of complexes 1-5 were determined by X-ray crystallography and the copper(II) ions were five coordinate. Cytotoxic activity of the complexes in four human cancer cell lines, A549 (lung carcinoma), MDA-MB-231 (breast carcinoma), HCT116 (colon carcinoma) and DU145 (prostate carcinoma), and a normal cell line, BEAS-2B (human lung epithelial), was determined by SRB assay and compared with that of 5-FU and cisplatin. The complexation of 5-FU together with polypyridyl ligands resulted in a significant increase in the cytotoxicity of the complexes, with complex 2 exhibiting the highest anticancer potency against all the cell lines, with HCT116 being the most sensitive. The mode of action of cell death for 2 was investigated using morphological imaging and cytometric analyses, including the capacity for induction of apoptosis, generation of reactive oxygen species, mitochondrial dysfunction and DNA damage.

Targeting Periostin Expression Makes Pancreatic Cancer Spheroids More Vulnerable to Natural Killer Cells.

Pancreatic cancer (PaCa) characteristically has a dense tumor microenvironment, which results in poor patient prognosis. Pancreatic stellate cells (PSCs) are the most abundant cells in the PaCa microenvironment and the principal source of collagen. Periostin, a matricellular protein, is produced specifically by PSCs and promotes the aggressiveness of PaCa cells by facilitating extracellular collagen assembly. Here, we aimed to decrease extracellular collagen assembly by suppressing periostin, thereby increasing the cytotoxic activity of natural killer (NK) cells. Periostin expression was suppressed in PSCs (called PSC-P) using CRISPR-Cas9. PaCa cells (BxPC-3) were co-cultured with PSC and PSC-P cells in a 3D environment to form tumor spheroids mimicking the tumor microenvironment. The extracellular collagen production of spheroids was evaluated by Masson's trichrome staining. The cytotoxic activity of NK-92 cells was analyzed by flow cytometry and confocal microscopy via CD107a staining. Cell death in BxPC-3 cells was evaluated by measuring Annexin-V and PI positivity using flow cytometry. As a result, periostin suppression decreased extracellular collagen and increased the infiltration of NK-92 cells into spheroids, and induced cell death in PaCa cells. In conclusion, we suggest that periostin might be a therapeutic target for PaCa and further analysis is warranted using in vivo models for proof-of-concept.

Evidence for heterogeneity in response to treatment in mammary tumors of dogs as happens in humans.

Tumors are formed by various clones developed over a long time. This gives rise to a heterogeneous nature. This heterogeneity is the hardest challenge in the treatment of cancers because it is the main reason for drug resistance. This is a well-known fact in human cancer. Therefore, we have reasoned that if the tumor heterogeneity in canine mammary gland tumors (CMGTs) could be shown by an ex vivo assay, which will be used first time in veterinary oncology practice, this could be used further in clinics. To achieve this, twenty-six patients were included in the study. Tumor tissues were obtained from animals during routine surgery. Tumor cells were isolated and seeded ex vivo. The cells were exposed to anticancer drugs that are clinically used. Seven days after the treatment, chemosensitivity has luminometrically been assayed by ATP-tumor chemosensitivity assay (ATP-TCA). It has clearly been shown that all the tumor tissues have responded to treatment differently, implying that heterogeneity exists in mammary tumors. There has also been found that there was a weak to moderate statistically significant correlation between tumor size and drug index. However, there has been no correlation between drug index and metastasis to lymph nodes. Hyperplasic areas had relatively higher PCNA values. The results of our study demonstrate the heterogeneity in responses to in vitro drugs. Clinical trials based on test results and follow-up studies with large numbers of animals are needed to prove that such chemotherapeutic activity assessment tests can be clinically useful in predicting drug responses in CMGTs.

DNA Damage Response Inhibitors in Cholangiocarcinoma: Current Progress and Perspectives.

Cholangiocarcinoma (CCA) is a poorly treatable type of cancer and its incidence is dramatically increasing. The lack of understanding of the biology of this tumor has slowed down the identification of novel targets and the development of effective treatments. Based on next generation sequencing profiling, alterations in DNA damage response (DDR)-related genes are paving the way for DDR-targeting strategies in CCA. Based on the notion of synthetic lethality, several DDR-inhibitors (DDRi) have been developed with the aim of accumulating enough DNA damage to induce cell death in tumor cells. Observing that DDRi alone could be insufficient for clinical use in CCA patients, the combination of DNA-damaging regimens with targeted approaches has started to be considered, as evidenced by many emerging clinical trials. Hence, novel therapeutic strategies combining DDRi with patient-specific targeted drugs could be the next level for treating cholangiocarcinoma.

Novel 5-fluorouracil complexes of Zn(II) with pyridine-based ligands as potential anticancer agents.

A series of novel Zn(II) complexes of 5-fluorouracilate (5-FU), namely [Zn(5-FU)2(bpy)] (1), [Zn(5-FU)2(phen)] (2), [Zn(5-FU)2(dpya)]·H2O (3), [Zn(5-FU)2(bpyma)]·2H2O (4) and [Zn(5-FU)2(terpy)]·H2O (5), were synthesized and structurally characterized by spectroscopic methods and X-ray crystallography. 5-FU was coordinated to Zn(II) via the deprotonated N3 site and also presented the N1 and N3 linkage isomerism in 4 and 5 due to its tautomerism. The antiproliferative activity of the complexes was studied against lung (A549), breast (MDA-MB-231), colon (HCT116) and prostate (DU145) cancer cell lines. Complexes 1, 4 and 5 except 2 and 3 showed potent growth inhibitory activity towards selected cancer cells. Remarkably, 4 was highly cytotoxic towards A549 and MDA-MB-231 cell lines, being more active than the clinical drugs cisplatin and 5-FU. In addition, 4 was not toxic to normal lung cells (BEAS-2B). The complex exhibited a significantly high affinity towards DNA as assessed by gel electrophoresis and DNA docking. The mechanistic studies of 4 in A549 cells indicated that the complex induced apoptotic cell death as evidenced via caspase 3/7 activity, Bcl2 inactivation, annexin V and DAPI/PI staining. 4 further elevated the levels of reactive oxygen species (ROS), depolarized mitochondria and enhanced the expression of γ-H2AX, thus contributing to its remarkable anticancer activity.

Development of a cysteine responsive chlorinated hemicyanine for image-guided dual phototherapy.

A cysteine (Cys) activatable chlorinated hemicyanine (Cl-Cys) was introduced as a tumour selective image-guided dual phototherapy agent. Cl-Cys exhibited a significant turn on response in its near-IR emission signal and activated its singlet oxygen generation as well as photothermal conversion potentials upon reacting with Cys. The laser irradiation of Cl-Cys induced significant cell death in cancer cells with high Cys level, while it stayed deactivated and non-emissive in a healthy cell line. A profound synergistic PDT/PTT effect was observed at high doses. Remarkably, Cl-Cys marks the first ever example of Cys-responsive small organic-based therapeutic agent and holds a great promise to develop new activity-based photosensitizers for dual phototherapy action.

Differential of cholangiocarcinoma disease using Raman spectroscopy combined with multivariate analysis.

Cholangiocarcinoma (CCA) is a type of cancer, which 5-year survival is lower than 20 %, and which is detected mostly in advanced stage of the disease. Unfortunately, there are no diagnostic tools, which could show changes in the body indicating the development of the disease. Therefore, in this study, we investigate Raman spectroscopy as a promising analytical tool in medical diagnostics and as a method, which would allow to distinguish between healthy patients and patients suffering from cholangiocarcinoma. The obtained Raman spectra showed, that lower intensities of peaks corresponding to amino acids and proteins, as well as higher intensities of peaks originating from lipids vibrations were observed in healthy individuals in comparison with cancer patients. Moreover, Partial Last Square (PLS), Principal Component Analysis (PCA) and Hierarchical Component Analysis (HCA) of Raman spectra indicate that the ranges between 800 cm-1 and 1800 cm-1, 3477 cm-1 -3322 cm-1 and 1394 cm-1 -1297 cm-1 allow to distinguish cancer patients from healthy ones. The obtained results showed, that Raman spectroscopy is a good candidate, to become in future one of the diagnostic tools of Cholangiocarcinoma.

Effects of Exosomes on Major Pathways Promote Tumor Formation and Progression.

Exosomal vesicles enclose and carry a broad range of biological molecules, such as nucleic acids, lipids, and proteins, and transfer them between cells. In cancer, cells being mentioned could be neighbors in the same tumor microenvironment communicating with each other, or they could be localized at distant sites of the body, enabling suitable conditions for metastasis. Either way, it is a concrete fact that cells under physiological or pathological conditions make crosstalk via exosomal secretion. This review looks at the relation between exosomal cargo and mechanisms of cancer through recent research.

Natural Products as a Promising Therapeutic Strategy to Target Cancer Stem Cells.

Cancer remains a deadly disease, and its treatment desperately needs to be managed through novel, rapidly advancing strategies. Most cancer cases eventually develop into recurrences, for which cancer stem cells (CSCs) are thought to be responsible. These cells are considered a subpopulation of all tumor cancer cells, with aberrant regulation of self-renewal, unbalanced proliferation, and cell death properties. CSCs show a marked degree of resistance to chemotherapy or radiotherapy and immune surveillance. To combat CSCs, new drugs are flooding the market each year, increasing the cost of therapy dramatically. Natural products are becoming a new research area, presenting a diverse chemical library to suppress CSCs and some natural products show great promise in this regard. In the near future, the introduction of natural products as a source of new chemotherapy modalities may result in the development of novel anticancer drugs that could be reasonably-priced alternatives to expensive current treatments. Lately preclinical and clinical research has focused on natural compounds' effects on targeting surface markers, signaling pathways, apoptosis, and escape from immunosurveillance. In this review, we present research on the mechanisms through which natural compounds kill CSCs and the potential use of natural compounds in the inhibition of CSCs.

Investigation of the efficacy of paclitaxel on some miRNAs profiles in breast cancer stem cells.

Understanding of the functions of microRNAs in breast cancer and breast cancer stem cells have been a hope for the development of new molecular targeted therapies. Here, it is aimed to investigate the differences in the expression levels of let-7a, miR-10b, miR-21, miR-125b, miR-145, miR-155, miR-200c, miR-221, miR-222 and miR-335, which associated with gene and proteins in MCF-7 (parental) and MCF-7s (Mammosphere/stem cell-enriched population/CD44+/CD24-cells) cells treated with paclitaxel. MCF-7s were obtained from parental MCF-7 cells. Cytotoxic activity of paclitaxel was determined by ATP assay. Total RNA isolation and cDNA conversion were performed from the samples. Changes in expression levels of miRNAs were examined by RT-qPCR. Identified target genes and proteins of miRNAs were analyzed with RT-qPCR and western blot analysis, respectively. miR-125b was significantly expressed (2.0946-fold; p = 0.021) in MCF-7s cells compared to control after treatment with paclitaxel. Downregulation of SMO, STAT3, NANOG, OCT4, SOX2, ERBB2 and ERBB3 and upregulation of TP53 genes were significant after 48 h treatment in MCF-7s cells. Protein expressions of SOX2, OCT4, SMAD4, SOX2 and OCT4 also decreased. Paclitaxel induces miR-125b expression in MCF-7s cells. Upregulation of miR-125b may be used as a biomarker for the prediction of response to paclitaxel treatment in breast cancer.

Water-soluble silver(i) complexes with N-donor benzimidazole ligands containing an imidazolium core: stability and preliminary biological studies.

Herein, we report the synthesis, characterisation and preliminary biological evaluation of two novel silver(i) complexes of type [AgL2](NO3)3 (3 and 4) with ionic N-donor benzimidazoles. The complexes have been synthesized by the reaction of 1.5 equivalents of silver nitrate and N-donor benzimidazoles containing an imidazolium core at the 2-position (1 and 2) in ethanol. The X-ray analysis of 4 shows that it has two free imidazolium cores and the charge is balanced with three nitrate anions. A study by the combination of NMR, IR, LC-MS and elemental analysis techniques also suggests that the complexes have this structure both in the solid-state and solution. The complexes are highly soluble and stable in water. Cytotoxicity evaluation against four cancerous human cells and one non-cancerous human cell revealed that the complexes have no significant anti-growth effect. However, the complexes showed a remarkable antimicrobial effect at normalized minimum inhibitory concentrations (normalized MICs) in the range of 33-268 µM against a panel of microorganisms consisting of Gram-negative and Gram-positive bacteria, and fungi.

Preparation and Characterization of Palladium Derivate-Loaded Micelle Formulation in Vitro as an Innovative Therapy Option against Non-Small Cell Lung Cancer Cells.

Nanoparticles have been used in cancer treatments to target tumor and reduce side effects. In this study, we aimed to increase the effectiveness of palladium(II) complex [PdCl(terpy)](sac) ⋅ 2H2 O, which previously showed anticancer potential, by preparing the nanoparticle formulation. An inhalable micellar dispersion containing a palladium(II) complex (PdNP) was prepared and its physicochemical characteristics were evaluated using in vitro tests. Morphology, size and surface charges of particle and loading/encapsulation efficiency of PdNP were analyzed by scanning electron microscopy, zeta sizer and inductively coupled plasma mass spectrometry while aerosol properties of PdNP were measured by the next generation impactor. A549 and H1299 non-small lung cancer cell types were used for cytotoxicity using SRB and ATP assays. Fluorescent staining and M30 antigen assay were carried out for cell death evaluation. Apoptosis was confirmed by flow cytometry analyses. SEM, particle size, and zeta potential results showed the particles have inhalable properties. The amount of the palladium(II) complex loaded into the particles was quantified which indicated high encapsulation efficiencies (97 %). The micellar dispersion expected to reach the alveolar region and the brachial region was determined 35 % and 47 %, respectively. PdNP showed an anti-growth effect by increasing reactive oxygen species that is followed by the induction of mitochondria-dependent apoptosis that is evidenced by pyknotic nuclei and M30 antigen level increments and disruption of polarization of membrane in mitochondria (Δψm). The results show that PdNP might be a promising inhalable novel complex to be used in non-small cell lung cancer, which warrants animal studies in further.

Palladium (II) complex and thalidomide intercept angiogenic signaling via targeting FAK/Src and Erk/Akt/PLCγ dependent autophagy pathways in human umbilical vein endothelial cells.

The current study assessed the effects of the thalidomide and palladium (II) saccharinate complex of terpyridine on the suppression of angiogenesis-mediated cell proliferation. The viability was assessed after treatment with palladium (II) complex (1.56-100 µM) and thalidomide (0.1-400 µM) alone by using ATP assay for 48 h. Palladium (II) complex was found to inhibit growth statistically significant in a dose-dependent manner in HUVECs and promoted PARP-1 cleavage through the production of ROS. On the other hand, thalidomide did not cause any significant change in cell viability. Moreover, cell death was observed to be manifested as late apoptosis due to Annexin V/SYTOX staining after palladium (II) complex treatment however, thalidomide did not demonstrate similar results. Thalidomide and palladium (II) complex also suppressed HUVEC migration and capillary-like structure tube formation in vitro in a time-dependent manner. Palladium (II) complex (5 mg/ml) treatment showed a strong antiangiogenic effect similar to positive control thalidomide (5 mg/ml) and successfully disrupted the vasculature and reduced the thickness of the vessels compared to control (agar). Furthermore, suppression of autophagy enhanced the cell death and anti-angiogenic effect of thalidomide and palladium (II) complex. We also showed that being treated with thalidomide and palladium (II) complex inhibited phosphorylation of the signaling regulators downstream of the VEGFR2. These results provide evidence for the regulation of endothelial cell functions that are relevant to angiogenesis through the suppression of the FAK/Src/Akt/ERK1/2 signaling pathway. Our results also indicate that PLC-γ1 phosphorylation leads to activation of p-Akt and p-Erk1/2 which cause stimulation on cell proliferation at lower doses. Hence, we demonstrated that palladium (II) and thalidomide can induce cell death via the Erk/Akt/PLCγ signaling pathway and that this pathway might be a novel mechanism.

Tumor Chemosensitivity Assays Are Helpful for Personalized Cytotoxic Treatments in Cancer Patients.

Tumor chemosensitivity assays (TCAs), also known as drug response assays or individualized tumor response tests, have been gaining attention over the past few decades. Although there have been strong positive correlations between the results of these assays and clinical outcomes, they are still not considered routine tests in the care of cancer patients. The correlations between the assays' results (drug sensitivity or resistance) and the clinical evaluations (e.g., response to treatment, progression-free survival) are highly promising. However, there is still a need to design randomized controlled prospective studies to secure the place of these assays in routine use. One of the best ideas to increase the value of these assays could be the combination of the assay results with the omics technologies (e.g., pharmacogenetics that gives an idea of the possible side effects of the drugs). In the near future, the importance of personalized chemotherapy is expected to dictate the use of these omics technologies. The omics relies on the macromolecules (Deoxyribonucleic acid -DNA-, ribonucleic acid -RNA-) and proteins (meaning the structure) while TCAs operate on living cell populations (meaning the function). Therefore, wise combinations of TCAs and omics could be a highly promising novel landscape in the modern care of cancer patients.

Epigenetic modulators combination with chemotherapy in breast cancer cells.

Despite the concerning adverse effects on tumour development, epigenetic drugs are very promising in cancer treatment. The aim of this study was to compare the differential effects of standard chemotherapy regimens (FEC: 5-fluorouracil plus epirubicine plus cyclophosphamide) in combination with epigenetic modulators (decitabine, valproic acid): (a) on gene methylation levels of selected tumour biomarkers (LINE-1, uPA, PAI-1, DAPK); (b) their expression status (uPA and PAI-1); (c) differentiation status (5meC and H3K27me3). Furthermore, cell survival as well as changes concerning the invasion capacity were monitored in cell culture models of breast cancer (MCF-7, MDA-MB-231). A significant overall decrease of cell survival was observed in the FEC-containing combination therapies for both cell lines. Methylation results showed a general tendency towards increased demethylation of the uPA and PAI-1 gene promoters for the MCF-7 cells, as well as the proapoptotic DAPK gene in the treatment regimens for both cell lines. The uPA and PAI-1 antigen levels were mainly increased in the supernatant of FEC-only treated MDA-MB-231 cells. DAC-only treatment induced an increase of secreted uPA protein in MCF-7 cell culture, while most of the VPA-containing regimens also induced uPA and PAI-1 expression in MCF-7 cell fractions. Epigenetically active substances can also induce a re-differentiation in tumour cells, as shown by 5meC, H3K27me3 applying ICC. SIGNIFICANCE OF THE STUDY: Epigenetic modulators especially in the highly undifferentiated and highly malignant MDA-MB-231 tumour cells significantly reduced tumour malignancy thus; further clinical studies applying specific combination therapies with epigenetic modulators may be warranted.

Pyruvate Dehydrogenase Contributes to Drug Resistance of Lung Cancer Cells Through Epithelial Mesenchymal Transition.

Recently, there has been a growing interest on the role of mitochondria in metastatic cascade. Several reports have shown the preferential utilization of glycolytic pathway instead of mitochondrial respiration for energy production and the pyruvate dehydrogenase (PDH) has been considered to be a contributor to this switch in some cancers. Since epithelial mesenchymal transition (EMT) is proposed to be one of the significant mediators of metastasis, the molecular connections between cancer cell metabolism and EMT may reveal underlying mechanisms and improve our understanding on metastasis. In order to explore a potential role for PDH inhibition on EMT and associated drug resistance, we took both pharmacological and genetic approaches, and selectively inhibited or knocked down PDHA1 by using Cpi613 and shPDHA1, respectively. We found that both approaches triggered morphological changes and characteristics of EMT (increase in mesenchymal markers). This change was accompanied by enhanced wound healing and an increase in migration. Interestingly, cells were more resistant to many of the clinically used chemotherapeutics following PDH inhibition or PDHA1 knockdown. Furthermore, the TGFßRI (known as a major inducer of the EMT) inhibitor (SB-431542) together with the PDHi, was effective in reversing EMT. In conclusion, interfering with PDH induced EMT, and more importantly resulted in chemoresistance. Therefore, our study demonstrates the need for careful consideration of PDH-targeting approaches in cancer treatment.