Differentially Expressed Mitochondrial Proteins in Human MCF7 Breast Cancer Cells Resistant to Paclitaxel

Effect of substituents at the C3´, C3´N, C10 and C2-meta-benzoate positions of taxane derivatives on their activity against resistant cancer cells

We tested the effect of substituents at the (1) C3´, C3´N, (2) C10, and (3) C2-meta-benzoate positions of taxane derivatives on their activity against sensitive versus counterpart paclitaxel-resistant breast (MCF-7) and ovarian (SK-OV-3) cancer cells. We found that (1) non-aromatic groups at both C3´ and C3´N positions, when compared with phenyl groups at the same positions of a taxane derivative, significantly reduced the resistance of ABCB1 expressing MCF-7/PacR and SK-OV-3/PacR cancer cells. This is, at least in the case of the SB-T-1216 series, accompanied by an ineffective decrease of intracellular levels in MCF-7/PacR cells. The low binding affinity of SB-T-1216 in the ABCB1 binding cavity can elucidate these effects. (2) Cyclopropanecarbonyl group at the C10 position, when compared with the H atom, seems to increase the potency and capability of the derivative in overcoming paclitaxel resistance in both models. (3) Derivatives with fluorine and methyl substituents at the C2-meta-benzoate position were variously potent against sensitive and resistant cancer cells. All C2 derivatives were less capable of overcoming acquired resistance to paclitaxel in vitro than non-substituted analogs. Notably, fluorine derivatives SB-T-121205 and 121,206 were more potent against sensitive and resistant SK-OV-3 cells, and derivatives SB-T-121405 and 121,406 were more potent against sensitive and resistant MCF-7 cells. (4) The various structure-activity relationships of SB-T derivatives observed in two cell line models known to express ABCB1 favor their complex interaction not based solely on ABCB1.

Compartmentalized mitochondrial ferroptosis converges with optineurin-mediated mitophagy to impact airway epithelial cell phenotypes and asthma outcomes

A stable mitochondrial pool is crucial for healthy cell function and survival. Altered redox biology can adversely affect mitochondria through induction of a variety of cell death and survival pathways, yet the understanding of mitochondria and their dysfunction in primary human cells and in specific disease states, including asthma, is modest. Ferroptosis is traditionally considered an iron dependent, hydroperoxy-phospholipid executed process, which induces cytosolic and mitochondrial damage to drive programmed cell death. However, in this report we identify a lipoxygenase orchestrated, compartmentally-targeted ferroptosis-associated peroxidation process which occurs in a subpopulation of dysfunctional mitochondria, without promoting cell death. Rather, this mitochondrial peroxidation process tightly couples with PTEN-induced kinase (PINK)-1(PINK1)-Parkin-Optineurin mediated mitophagy in an effort to preserve the pool of functional mitochondria and prevent cell death. These combined peroxidation processes lead to altered epithelial cell phenotypes and loss of ciliated cells which associate with worsened asthma severity. Ferroptosis-targeted interventions of this process could preserve healthy mitochondria, reverse cell phenotypic changes and improve disease outcomes.

Recent Contributions of Mass Spectrometry-Based "Omics" in the Studies of Breast Cancer

Breast cancer (BC) is one of the most heterogeneous groups of cancer. As every biotype of BC is unique and presents a particular "omic" signature, they are increasingly characterized nowadays with novel mass spectrometry (MS) strategies. BC therapeutic approaches are primarily based on the two features of human epidermal growth factor receptor 2 (HER2) and estrogen receptor (ER) positivity. Various strategic MS implementations are reported in studies of BC also involving data independent acquisitions (DIAs) of MS which report novel differential proteomic, lipidomic, proteogenomic, phosphoproteomic, and metabolomic characterizations associated with the disease and its therapeutics. Recently many "omic" studies have aimed to identify distinct subsidiary biotypes for diagnosis, prognosis, and targets of treatment. Along with these, drug-induced-resistance phenotypes are characterized by "omic" changes. These identifying aspects of the disease may influence treatment outcomes in the near future. Drug quantifications and characterizations are also done regularly and have implications in therapeutic monitoring and in drug efficacy assessments. We report these studies, mentioning their implications toward the understanding of BC. We briefly provide the MS instrumentation principles that are adopted in such studies as an overview with a brief outlook on DIA-MS strategies. In all of these, we have chosen a model cancer for its revelations through MS-based "omics".

Circular RNA sequencing identified circARNTL2 as a pathogenic factor in psoriasis by facilitating proliferation and cell cycle progression of keratinocytes

Psoriasis is a chronic recurrent skin disease, with excessive proliferation of keratinocytes. Recent studies indicated the pathogenic roles of circular RNA (circRNA) in psoriasis. Here, we screened the circRNA profiles from five psoriatic skin lesions and five normal skin tissues by circRNA sequencing and identified 1118 differentially expressed circRNAs (DECs) between psoriatic and normal groups. Among these DECs, high abundant circARNTL2 has been proven upregulated in psoriatic skin lesions by RT-qPCR assay. Then, the head-to-tail structure of circARNTL2 was validated by Sanger sequencing and RNase R digestion assay. Moreover, we determined cytoplastic location of circARNTL2 by RT-qPCR assay of nuclear/cytoplasmic RNA and FISH analysis. Further experiments demonstrated that silencing circARNTL2 expression could block cell proliferation and cell cycle progression of keratinocytes. Mechanistically, circARNTL2 can bind to and regulate Serpin B4 which also affects the proliferation of keratinocytes. These findings provide evidence for the role of circARNTL2 in psoriasis.

Underexpression of Carbamoyl Phosphate Synthetase I as Independent Unfavorable Prognostic Factor in Intrahepatic Cholangiocarcinoma: A Potential Theranostic Biomarker

Intrahepatic cholangiocarcinoma (IHCC) is the second most common malignant neoplasm of the liver. In spite of the increasing incidence worldwide, it is relatively rare in Western countries. IHCC is relatively common in Eastern and Southeastern Asia. Patients with IHCC are usually diagnosed at an advanced stage, therefore, the clinical outcome is dismal. Dysregulation of urea cycle metabolic enzyme expression is found in different types of cancers. Nevertheless, a comprehensive evaluation of genes related to the urea cycle (i.e., GO:0000050) has not been conducted in IHCC. By performing a comparative analysis of gene expression profiles, we specifically examined genes associated with the urea cycle (GO:0000050) in a publicly accessible transcriptomic dataset (GSE26566). Interestingly, CPS1 was identified as the second most prominently down-regulated gene in this context. Tumor tissues of 182 IHCC patients who underwent curative-intent hepatectomy were enrolled. The expression level of CPS1 protein in our IHCC cohort was assessed by immunohistochemical study. Subsequent to that, statistical analyses were carried out to examine the expression of CPS1 in relation to various clinicopathological factors, as well as to assess its impact on survival outcomes. We noticed that lower immunoreactivity of CPS1 in IHCC was associated with tumor progression (pT status) with statistical significance (p = 0.003). CPS1 underexpression was not only negatively correlated to overall survival (OS), disease-free survival (DFS), local recurrence-free survival (LRFS) and metastasis-free survival (MeFS) in univariate analysis but also an independent prognosticator to forecast poorer clinical outcome for all prognostic indices (OS, DFS, LRFS and MeFs) in patients with IHCC (all p ≤ 0.001). These results support that CPS1 may play a crucial role in IHCC oncogenesis and tumor progression and serve as a novel prognostic factor and a potential diagnostic and theranostic biomarker.

ABCB1 Amplicon Contains Cyclic AMP Response Element-Driven TRIP6 Gene in Taxane-Resistant MCF-7 Breast Cancer Sublines

A limited number of studies are devoted to regulating TRIP6 expression in cancer. Hence, we aimed to unveil the regulation of TRIP6 expression in MCF-7 breast cancer cells (with high TRIP6 expression) and taxane-resistant MCF-7 sublines (manifesting even higher TRIP6 expression). We found that TRIP6 transcription is regulated primarily by the cyclic AMP response element (CRE) in hypomethylated proximal promoters in both taxane-sensitive and taxane-resistant MCF-7 cells. Furthermore, in taxane-resistant MCF-7 sublines, TRIP6 co-amplification with the neighboring ABCB1 gene, as witnessed by fluorescence in situ hybridization (FISH), led to TRIP6 overexpression. Ultimately, we found high TRIP6 mRNA levels in progesterone receptor-positive breast cancer and samples resected from premenopausal women.

Ketone-selenoesters as potential anticancer and multidrug resistance modulation agents in 2D and 3D ovarian and breast cancer in vitro models

Long-term treatment of cancer with chemotherapeutics leads to the development of resistant forms that reduce treatment options. The main associated mechanism is the overexpression of transport proteins, particularly P-glycoprotein (P-gp, ABCB1). In this study, we have tested the anticancer and multidrug resistance (MDR) modulation activity of 15 selenocompounds. Out of the tested compounds, K3, K4, and K7 achieved the highest sensitization rate in ovarian carcinoma cells (HOC/ADR) that are resistant to the action of the Adriamycin. These compounds induced oxidation stress, inhibited P-gp transport activity and altered ABC gene expression. To verify the effect of compounds, 3D cell models were used to better mimic in vivo conditions. K4 and K7 triggered the most significant ROS release. All selected selenoesters inhibited P-gp efflux in a dose-dependent manner while simultaneously altering the expression of the ABC genes, especially P-gp in paclitaxel-resistant breast carcinoma cells (MCF-7/PAX). K4, and K7 demonstrated sensitization potential in resistant ovarian spheroids. Additionally, all selected selenoesters achieved a high cytotoxic effect in 3D breast and ovarian models, which was comparable to that in 2D cultures. K7 was the only non-competitive P-gp inhibitor, and therefore appears to have considerable potential for the treatment of drug-resistant cancer.

The Role of TRIP6, ABCC3 and CPS1 Expression in Resistance of Ovarian Cancer to Taxanes

The main problem precluding successful therapy with conventional taxanes is de novo or acquired resistance to taxanes. Therefore, novel experimental taxane derivatives (Stony Brook taxanes; SB-Ts) are synthesized and tested as potential drugs against resistant solid tumors. Recently, we reported alterations in ABCC3, CPS1, and TRIP6 gene expression in a breast cancer cell line resistant to paclitaxel. The present study aimed to investigate gene expression changes of these three candidate molecules in the highly resistant ovarian carcinoma cells in vitro and corresponding in vivo models treated with paclitaxel and new experimental Stony Brook taxanes of the third generation (SB-T-121605 and SB-T-121606). We also addressed their prognostic meaning in ovarian carcinoma patients treated with taxanes. We estimated and observed changes in mRNA and protein profiles of ABCC3, CPS1, and TRIP6 in resistant and sensitive ovarian cancer cells and after the treatment of resistant ovarian cancer models with paclitaxel and Stony Brook taxanes in vitro and in vivo. Combining Stony Brook taxanes with paclitaxel caused downregulation of CPS1 in the paclitaxel-resistant mouse xenograft tumor model in vivo. Moreover, CPS1 overexpression seems to play a role of a prognostic biomarker of epithelial ovarian carcinoma patients’ poor survival. ABCC3 was overexpressed in EOC tumors, but after the treatment with taxanes, its up-regulation disappeared. Based on our results, we can suggest ABCC3 and CPS1 for further investigations as potential therapeutic targets in human cancers.

Quantitative dSTORM super-resolution microscopy localizes Aurora kinase A/AURKA in the mitochondrial matrix

BACKGROUND INFORMATION

Mitochondria are dynamic organelles playing essential metabolic and signaling functions in cells. Their ultrastructure has largely been investigated with electron microscopy (EM) techniques. However, quantifying protein-protein proximities using EM is extremely challenging. Super-resolution microscopy techniques as direct stochastic optical reconstruction microscopy (dSTORM) now provide a fluorescent-based, quantitative alternative to EM. Recently, super-resolution microscopy approaches including dSTORM led to valuable advances in our knowledge of mitochondrial ultrastructure, and in linking it with new insights in organelle functions. Nevertheless, dSTORM is mostly used to image integral mitochondrial proteins, and there is little or no information on proteins transiently present at this compartment. The cancer-related Aurora kinase A/AURKA is a protein localized at various subcellular locations, including mitochondria.

RESULTS

We first demonstrate that dSTORM coupled to GcoPS can resolve protein proximities within individual submitochondrial compartments. Then, we show that dSTORM provides sufficient spatial resolution to visualize and quantify the most abundant pool of endogenous AURKA in the mitochondrial matrix, as previously shown for overexpressed AURKA. In addition, we uncover a smaller pool of AURKA localized at the OMM, which could have a potential functional readout. We conclude by demonstrating that aldehyde-based fixatives are more specific for the OMM pool of the kinase instead.

CONCLUSIONS

Our results indicate that dSTORM coupled to GcoPS colocalization analysis is a suitable approach to explore the compartmentalization of non-integral mitochondrial proteins as AURKA, in a qualitative and quantitative manner. This method also opens up the possibility of analyzing the proximity between AURKA and its multiple mitochondrial partners with exquisite spatial resolution, thereby allowing novel insights into the mitochondrial functions controlled by AURKA.

SIGNIFICANCE

Probing and quantifying the presence of endogenous AURKA - a cell cycle-related protein localized at mitochondria - in the different organelle subcompartments, using quantitative dSTORM super-resolution microscopy.

α/β-Hydrolase Domain (ABHD) Inhibitors as New Potential Therapeutic Options against Lipid-Related Diseases

Much of the experimental evidence in the literature has linked altered lipid metabolism to severe diseases such as cancer, obesity, cardiovascular pathologies, diabetes, and neurodegenerative diseases. Therefore, targeting key effectors of the dysregulated lipid metabolism may represent an effective strategy to counteract these pathological conditions. In this context, α/β-hydrolase domain (ABHD) enzymes represent an important and diversified family of proteins, which are involved in the complex environment of lipid signaling, metabolism, and regulation. Moreover, some members of the ABHD family play an important role in the endocannabinoid system, being designated to terminate the signaling of the key endocannabinoid regulator 2-arachidonoylglycerol. This Perspective summarizes the research progress in the development of ABHD inhibitors and modulators: design strategies, structure-activity relationships, action mechanisms, and biological studies of the main ABHD ligands will be highlighted.

Identification of the hub genes in gastric cancer through weighted gene co-expression network analysis

Background

Gastric cancer is one of the most lethal tumors and is characterized by poor prognosis and lack of effective diagnostic or therapeutic biomarkers. The aim of this study was to find hub genes serving as biomarkers in gastric cancer diagnosis and therapy.

Methods

GSE66229 from Gene Expression Omnibus (GEO) was used as training set. Genes bearing the top 25% standard deviations among all the samples in training set were performed to systematic weighted gene co-expression network analysis (WGCNA) to find candidate genes. Then, hub genes were further screened by using the “least absolute shrinkage and selection operator” (LASSO) logistic regression. Finally, hub genes were validated in the GSE54129 dataset from GEO by supervised learning method artificial neural network (ANN) algorithm.

Results

Twelve modules with strong preservation were identified by using WGCNA methods in training set. Of which, five modules significantly related to gastric cancer were selected as clinically significant modules, and 713 candidate genes were identified from these five modules. Then, ADIPOQ, ARHGAP39, ATAD3A, C1orf95, CWH43, GRIK3, INHBA, RDH12, SCNN1G, SIGLEC11 and LYVE1 were screened as the hub genes. These hub genes successfully differentiated the tumor samples from the healthy tissues in an independent testing set through artificial neural network algorithm with the area under the receiver operating characteristic curve at 0.946.

Conclusions

These hub genes bearing diagnostic and therapeutic values, and our results may provide a novel prospect for the diagnosis and treatment of gastric cancer in the future.