Loss of E-Cadherin Leads to Druggable Vulnerabilities in Sphingolipid Metabolism and Vesicle Trafficking

Germline inactivating variants of CDH1 are causative of hereditary diffuse gastric cancer (HDGC), a cancer syndrome characterzsed by an increased risk of both diffuse gastric cancer and lobular breast cancer. Because loss of function mutations are difficult to target therapeutically, we have taken a synthetic lethal approach to identify targetable vulnerabilities in CDH1-null cells. We have previously observed that CDH1-null MCF10A cells exhibit a reduced rate of endocytosis relative to wildtype MCF10A cells. To determine whether this deficiency is associated with wider vulnerabilities in vesicle trafficking, we screened isogenic MCF10A cell lines with known inhibitors of autophagy, endocytosis, and sphingolipid metabolism. Relative to wildtype MCF10A cells, CDH1−/− MCF10A cells showed significantly greater sensitivity to several drugs targeting these processes, including the autophagy inhibitor chloroquine, the endocytosis inhibitors chlorpromazine and PP1, and the sphingosine kinase 1 inhibitor PF-543. Synthetic lethality was confirmed in both gastric and mammary organoid models of CDH1 loss, derived from CD44-Cre/Cdh1fl/fl/tdTomato mice. Collectively, these results suggest that both sphingolipid metabolism and vesicle trafficking represent previously unrecognised druggable vulnerabilities in CDH1-null cells and may lead to the development of new therapies for HDGC.

In-Vitro Cytotoxicity and Anticancer Drug Release Behavior of Methionine - Coated Magnetite Nanoparticles As Carriers.

An innovative and customized drug delivery system for in vitro cancer treatment has been developed successfully by a simple one-step method. A CoFe2O4@Methionine core-shell nanoparticle was prepared by the reflux assay, in which amino acid on the surface makes the ferrite biocompatible, enhances the chemical stability of the compound, and increases the drug loading capacity. The synthesized nanoparticles were evaluated using SEM, TEM, FTIR, and VSM, while XRD and TGA analysis verified the presence of a coating amino acid on the surface of CoFe2O4. The appearance of a new peak for C≡N in the FTIR spectrum validates the synthesis of a letrozole-loaded carrier. Both uncoated CoFe2O4 and methionine-coated CoFe2O4 nanoparticles behave super-paramagnetically at room temperature, with saturation values of 46 emu/g and 16.8 emu/g, respectively. SEM and TEM were used to characterize the morphology and size of samples, revealing that the average particle size was around 28–29 nm. The loading of Letrozole and the effect of pH (5, 7.4) on the release behavior of the carrier were studied. The result of the drug release in pH (5) was about 88% higher than pH (7.4). Also, the preparation has been evaluated for determining its cytotoxicity using MCF-7, MDA-MB-231, and MCF10A cell lines as an in vitro model, and the results of in vitro experiments showed that CoFe2O4@Methionine could significantly reduce cancer in the cell model. These results demonstrate that core-shell nanoparticles were prepared that are biocompatible and have potential use as drug delivery.

In Vitro Anti-Tubulin Activity on MCF10A Cell Line and In Silico Rigid/Semiflexible-Residues Docking, of Two Lignans from Bursera Fagaroides var. Fagaroides

Podophyllotoxins are natural lignans with known cytotoxic activity on several cell lines. The structural basis for their actions is mainly by the aryltetralin-lignan skeleton. Authors have proposed a cytotoxic mechanism of podophyllotoxins through the topoisomerase-II inhibition activity; however, several studies have also suggested that podophyllotoxins can inhibit the microtubules polymerization. In this work, the two possible mechanisms of action of two previously isolated compounds from the stem bark of Bursera fagaroides var. fagaroides: acetylpodophyllotoxin (1) and 5’-desmethoxydeoxypodophyllotoxin (2), was analyzed. An in vitro anti-tubulin epifluorescence on the MCF10A cell line and enzymatic topoisomerase II assays were performed. The binding affinities of compounds 1 and 2 in the colchicine binding site of tubulin by using rigid- and semiflexible-residues were calculated and compared using in silico docking methods. The two lignans were active by the in vitro anti-tubulin assay but could not inhibit TOP2 activity. In the in silico analysis, the binding modes of compounds into both rigid- and semiflexible-residues of tubulin were predicted, and only for the semiflexible docking method, a linear correlation between the dissociation constant and IC50 previously reported was found. Our results suggest that a simple semiflexible-residues modification in docking methods could provide an in vitro correlation when analyzing very structurally similar compounds.

Study of danazol active agent effect on Mcf10a breast cells redox phosphorylation

Fibrocystic mastopathy is one of the most complex breast pathologies, occurring in about 60% of women. The causes and molecular mechanisms of cyst formation in fibrocystic mastopathy are not fully understood, and effective treatment methods are not widely implemented. However, there is evidence of the fibrocystic mastopathy malignization risk. We studied the molecular effect of the active agent danazol on the respiratory complex in mitochondria, which occur in various concentrations and are considered the cell energy center. A method of permeation with special agents was developed to improve the cell membrane permeability in the intracellular proteins and nucleic acids analysis. The scientists aimed to study the Mcf10a cell line mitochondrial respiratory complex using the permeabilization method. Purpose: To study the effect of different danazol concentrations on Mcf10a breast cells redox phosphorylation in women with fibrocystic mastopathy. Results: Monitoring the redox phosphorylation process using complex respiratory substrates affecting the Msf10A breast cells respiratory chain showed the danazol 30 μM effect on the respiratory complex I. Conclusions: According to oxygraphic records, 10 minutes’ exposure to danazol 30 μM after permeabilization with digitonin increased the Msf10A cells’ oxidative phosphorylation compared with the control. The respiratory rate decreased by 45% ten minutes after treatment with digitonin.

The Δ40p53 isoform inhibits p53-dependent eRNA transcription and enables regulation by signal-specific transcription factors during p53 activation

The naturally occurring Δ40p53 isoform heterotetramerizes with wild-type p53 (WTp53) to regulate development, aging, and stress responses. How Δ40p53 alters WTp53 function remains enigmatic because their co-expression causes tetramer heterogeneity. We circumvented this issue with a well-tested strategy that expressed Δ40p53:WTp53 as a single transcript, ensuring a 2:2 tetramer stoichiometry. Human MCF10A cell lines expressing Δ40p53:WTp53, WTp53, or WTp53:WTp53 (as controls) from the native TP53 locus were examined with transcriptomics (precision nuclear run-on sequencing [PRO-seq] and RNA sequencing [RNA-seq]), metabolomics, and other methods. Δ40p53:WTp53 was transcriptionally active, and, although phenotypically similar to WTp53 under normal conditions, it failed to induce growth arrest upon Nutlin-induced p53 activation. This occurred via Δ40p53:WTp53-dependent inhibition of enhancer RNA (eRNA) transcription and subsequent failure to induce mRNA biogenesis, despite similar genomic occupancy to WTp53. A different stimulus (5-fluorouracil [5FU]) also showed Δ40p53:WTp53-specific changes in mRNA induction; however, other transcription factors (TFs; e.g., E2F2) could then drive the response, yielding similar outcomes vs. WTp53. Our results establish that Δ40p53 tempers WTp53 function to enable compensatory responses by other stimulus-specific TFs. Such modulation of WTp53 activity may be an essential physiological function for Δ40p53. Moreover, Δ40p53:WTp53 functional distinctions uncovered herein suggest an eRNA requirement for mRNA biogenesis and that human p53 evolved as a tetramer to support eRNA transcription.

Cellular Pharmacology of Curcumin With and Without Piperine

Prior reports have suggested that piperine enhances curcumin anti-carcinogenesis. We tested the hypothesis that piperine increases the intracellular concentrations of curcumin by improving intracellular uptake or reducing curcumin efflux or metabolism in breast cells. We incubated SUM149, MCF10A, primary normal human breast cells, ALDH+, and ALDH-CD44+24- SUM149 cells with curcumin with or without piperine at concentrations 1 uM to 15 uM for time periods of 15 minutes to 24 hours. We assayed cell viability by MTT assay and proliferation by primary mammosphere assay. Curcumin and its metabolites were assayed using liquid chromatography mass spectroscopy. Curcumin, but not piperine, showed significantly higher effects on the viability of breast cancer SUM149 cells than in non-tumorigenic MCF10A cells. Curcumin + piperine synergistically reduced viability of SUM149 cells but had a concentration dependent effect upon MCF10A cell viability. Cellular uptake of curcumin in SUM149 is significantly higher, while the efflux in SUM149 is significantly lower than in MCF10A, which correlated with cell viability. Piperine did not alter curcumin cellular uptake, efflux, or metabolism in any of the cell models. The observed synergism of piperine+curcumin in reducing breast stem cell self renewal is likely due to independent anti-carcinogenesis effects rather than any effects upon intracellular curcumin concentrations.

Study of danazol active agent effect on Mcf10a breast cells redox phosphorylation

Relevance: Fibrocystic mastopathy is one of the most complex breast pathologies, occurring in about 60% of women. The causes and molecular mechanisms of cyst formation in fibrocystic mastopathy are not fully understood, and effective treatment methods are not widely implemented. However, there is evidence of the fibrocystic mastopathy malignization risk. We studied the molecular effect of the active agent danazol on the respiratory complex in mitochondria, which occur in various concentrations and are considered the cell energy center. A method of permeation with special substances was developed to improve the cell membrane permeability in the intracellular proteins and nucleic acids analysis. The scientists aimed to study the Mcf10a cell line mitochondrial respiratory complex using the permeabilization method. Purpose: To study the effect of different danazol concentrations on Mcf10a breast cells redox phosphorylation in women with fibrocystic mastopathy. Results: Monitoring the redox phosphorylation process using the respiratory complex substrates affecting the Msf10A breast cells respiratory chain showed the danazol 30 μM effect on the respiratory complex I. Conclusions: According to oxygraphic records, 10 minutes’ exposure to danazol 30 μM after permeabilization with digitonin increased the Msf10A cells’ oxidative phosphorylation compared with the control. The respiratory rate decreased by 45% ten minutes after treatment with digitonin.

Mass Cytometric and Transcriptomic Profiling of Epithelial-Mesenchymal Transitions in Human Mammary Cell Lines

Epithelial-mesenchymal transition (EMT) equips breast cancer cells for metastasis and treatment resistance. Inhibition and elimination of EMT-undergoing cells are therefore promising therapy approaches. However, detecting EMT-undergoing cells is challenging due to the intrinsic heterogeneity of cancer cells and the phenotypic diversity of EMT programs. Here, we profiled EMT transition phenotypes in four non-cancerous human mammary epithelial cell lines using a FACS surface marker screen, RNA sequencing, and mass cytometry. EMT was induced in the HMLE and MCF10A cell lines and in the HMLE-Twist-ER and HMLE-Snail-ER cell lines by chronic exposure to TGFβ1 or 4-hydroxytamoxifen, respectively. We observed a spectrum of EMT transition phenotypes in each cell line and the spectrum varied across the time course. Our data provide multiparametric insights at single-cell level into the phenotypic diversity of EMT at different time points and in four human cellular models. These insights are valuable to better understand the complexity of EMT, to compare EMT transitions between the cellular models used herein, and for the design of EMT time course experiments.

Proteome of breast cancer derived microvesicles

The aim of the research. To examine the proteomic profi le of breast cancer exosomes. Material and methods. Cell lines used for this study were MDA-MB-231 female epithelial breast cancer cells (ATCC HTB-26) and MCF10A non-tumorigenic epithelial breast tissue cells. MVs were isolated using diff erential ultracentrifugation. Samples were lysed, reduced, alkylated, digested, and analyzed by an Orbitrap Fusion mass spectrometer. MS raw fi les were analyzed using MaxQuant version 1.6.12.0. Peptides were searched against the human UniProt FASTA database using the Andromeda search engine, integrated into MaxQuant. Results. MVs derived from MCF10A and MDA-MB-231 cell lines were analyzed, and 1427 and 547 proteins were identifi ed in the MDA-MB-231 and MCF10A-derived MVs, respectively. In total, 455 proteins were common to both MDA-MB-231 and MCF10A MVs. MVs derived from MCF10A and MDAMB-231 cell lines were analyzed, and 1427 and 547 proteins were identifi ed in the MDA-MB-231 and MCF10A-derived MVs, respectively. In total, 455 proteins were common to both MDA-MB-231 and MCF10A MVs. Th e unique MDA-MB-231 MV proteins were searched against the DisGeNET human diseases database. Out of 972 MDA-MB-231 MV proteins, 112 were cancer-related while 32 were specifi cally associated with BC. In the MDA-MB-231 MV proteome, 23 Wnt signaling pathway proteins were identifi ed based on their GO biological process. Proteomic analysis identifi ed enzymes OAT, TALDO1, and BLMH were only in MVs from metastatic MDA-MB-231 cell line. The specific activity of OAT and TALDO1 was higher in MV fractions of MDA-MB-231 in comparison to the non-cancerous MCF10A cell line-derived MVs. Th ese fi ndings might suggest that these enzymes might play a role in BC. In our present study, we found that some enzymes identifi ed from MV fractions were already proposed to play a role in cancer therapy as therapeutic targets (OAT, TALDO1) and resistance against chemotherapy agents (BLMH).

Cohesin mutations are synthetic lethal with stimulation of WNT signaling

Mutations in genes encoding subunits of the cohesin complex are common in several cancers, but may also expose druggable vulnerabilities. We generated isogenic MCF10A cell lines with deletion mutations of genes encoding cohesin subunits SMC3, RAD21, and STAG2 and screened for synthetic lethality with 3009 FDA-approved compounds. The screen identified several compounds that interfere with transcription, DNA damage repair and the cell cycle. Unexpectedly, one of the top ‘hits’ was a GSK3 inhibitor, an agonist of Wnt signaling. We show that sensitivity to GSK3 inhibition is likely due to stabilization of β-catenin in cohesin-mutant cells, and that Wnt-responsive gene expression is highly sensitized in STAG2-mutant CMK leukemia cells. Moreover, Wnt activity is enhanced in zebrafish mutant for cohesin subunits stag2b and rad21. Our results suggest that cohesin mutations could progress oncogenesis by enhancing Wnt signaling, and that targeting the Wnt pathway may represent a novel therapeutic strategy for cohesin-mutant cancers.