Copy Number Variations as Determinants of Colorectal Tumor Progression in Liquid Biopsies.

Over the years, increasing evidence has shown that copy number variations (CNVs) play an important role in the pathogenesis and prognosis of Colorectal Cancer (CRC). Colorectal adenomas are highly prevalent lesions, but only 5% of these adenomas ever progress to carcinoma. This review summarizes the different CNVs associated with adenoma-carcinoma CRC progression and with CRC staging. Characterization of CNVs in circulating free-RNA and in blood-derived exosomes augers well with the potential of using such assays for patient management and early detection of metastasis. To overcome the limitations related to tissue biopsies and tumor heterogeneity, using CNVs to characterize tumor-derived materials in biofluids provides less invasive sampling methods and a sample that collectively represents multiple tumor sites in heterogeneous samples. Liquid biopsies provide a source of circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), tumor-derived exosomes (TDE), circulating free RNA, and non-coding RNA. This review provides an overview of the current diagnostic and predictive models from liquid biopsies.

Somatic copy number aberrations in metastatic patients: The promise of liquid biopsies.

Cancer metastasis is the leading cause of cancer-related mortality. The metastatic process involves measurable cellular changes that confer migratory potential, proliferative advantage and the ability to colonise a distinct microenvironment. Accumulation of aberrations and clonal evolution add complexity to patient management and the assessment of the therapeutic sensitivity profile of malignancies. Liquid biopsy presents a repeatable and minimally invasive assessment tool to detect early metastasis, characterise tumour phenotype and detect minimal residual disease. The promise of liquid biopsies is to inform patient management and therapeutic decisions in a timely manner. Clinical translation requires robust methodologies with high sensitivity and tumour specificity. This can be achieved through technological advances but also through novel biologically informed approaches that harness existing knowledge on tumorigenesis. Here we present a review of copy number variations as potential biomarkers for early detection of metastatic potential and outline a biomarker validation process in the context of liquid biopsies.

A loop involving NRF2, miR-29b-1-5p and AKT, regulates cell fate of MDA-MB-231 triple-negative breast cancer cells.

The present study shows that nuclear factor erythroid 2-related factor 2 (NRF2) and miR-29b-1-5p are two opposite forces which could regulate the fate of MDA-MB-231 cells, the most studied triple-negative breast cancer (TNBC) cell line. We show that NRF2 activation stimulates cell growth and markedly reduces reactive oxygen species (ROS) generation, whereas miR-29b-1-5p overexpression increases ROS generation and reduces cell proliferation. Moreover, NRF2 downregulates miR-29b-1-5p expression, whereas miR-29b-1-5p overexpression decreases p-AKT and p-NRF2. Furthermore, miR-29b-1-5p overexpression induces both inhibition of DNA N-methyltransferases (DNMT1, DNMT3A, and DNMT3B) expression and re-expression of HIN1, RASSF1A and CCND2. Conversely, NRF2 activation induces opposite effects. We also show that parthenolide, a naturally occurring small molecule, induces the expression of miR-29b-1-5p which could suppress NRF2 activation via AKT inhibition. Overall, this study uncovers a novel NRF2/miR-29b-1-5p/AKT regulatory loop that can regulate the fate (life/death) of MDA-MB-231 cells and suggests this loop as therapeutic target for TNBC.

Bead-based RNA multiplex panels for biomarker detection in oncology samples.

Patient stratification, prognosis and disease monitoring are three important aspects of personalized cancer medicine. With traditional serum tumour protein biomarkers showing lack of specificity and sensitivity, and tumour heterogeneity affecting the response to targeted therapy based on tissue biomarkers, the focus has shifted to the use of molecular tumour signatures as specific biomarkers. Multiplex microsphere-based panels are robust and cost-effective, high throughput molecular assays, which can accurately characterize tumours even from small amounts of poor quality nucleic acids. Only few studies have reported the use of microspheres (beads) to quantify RNA expression of targets of interest simultaneously (multiplexing). This review is an overview of the various applications of bead-based RNA panels in molecular oncology, with focus on the Invitrogen™ QuantiGene™ Plex Assay (Thermo Fisher Scientific), and provides a comparison with PCR-based and other methodologies. The advantages of multiplex bead assays are exemplified by the quantification of RNA expression in formalin-fixed, paraffin embedded (FFPE) archival tissue and the simultaneous detection of biomarkers in low input samples, including quantification of markers in microdissected tissue material, to characterise heterogeneous tumour sites within a sample, and by the detection of markers in low numbers of circulating tumour cells.

Loss of MCL1 function sensitizes the MDA-MB-231 breast cancer cells to rh-TRAIL by increasing DR4 levels.

Triple-negative breast cancer (TNBC) is a form of BC characterized by high aggressiveness and therapy resistance probably determined by cancer stem cells. MCL1 is an antiapoptotic Bcl-2 family member that could limit the efficacy of anticancer agents as recombinant human tumor necrosis factor related apoptosis-inducing ligand (rh-TRAIL). Here, we investigated MCL1 expression in TNBC tissues and cells. We found MCL1 differentially expressed (upregulated or downregulated) in TNBC tissues. Furthermore, in comparison to the human mammary epithelial cells, we found that MDA-MB-231 cells show similar messenger RNA levels but higher MCL1 protein levels, whereas it resulted downregulated in MDA-MB-436 and BT-20 cells. We evaluated the effects of rh-TRAIL and A-1210477, a selective MCL1 inhibitor, on cell viability and growth of MDA-MB-231 cells. We demonstrated that the drug combination reduced the cell growth and activated the apoptotic pathway. Similar effects were observed on three-dimensional cultures and tertiary mammospheres of MDA-MB-231 cells. In MDA-MB-231 cells, after MCL1 silencing, rh-TRAIL confined the cell population in the sub-G0/G1 phase and induced a drop in the mitochondrial transmembrane potential. To understand the molecular mechanism by which the loss of MCL1 function sensitizes the MDA-MB-231 cells to rh-TRAIL, we analyzed by real-time reverse transcription polymerase chain reaction, the expression of genes related to apoptosis, stemness, cell cycle, and those involved in epigenetic regulation. Interestingly, among the upregulated genes through MCL1 silencing or inhibition, there was TNFRSF10A (DR4). Moreover, MCL1 inhibition increased DR4 protein levels and its cell surface expression. Finally, we demonstrated MCL1-DR4 interaction and dissociation of this complex after A-1210477 treatment. Overall, our findings highlight the potential MCL1-roles in MDA-MB-231 cells and suggest that MCL1 targeting could be an effective strategy to overcome TNBC's rh-TRAIL resistance.

CIP2A expression predicts recurrences of tamoxifen-treated breast cancer.

CIP2A is emerging as an oncoprotein overexpressed commonly across many tumours and generally correlated with higher tumour grade and therapeutic resistance. CIP2A drives an oncogenic potential through inhibiting protein phosphatase 2A, stabilizing MYC, and promoting epithelial-to-mesenchymal transition, although further biological mechanisms for CIP2A are yet to be defined. CIP2A protein expression was studied by immunohistochemistry in oestrogen receptor-positive primary breast cancers (n = 250) obtained from the Leeds Tissue Bank. In total, 51 cases presented with a relapse or metastasis during adjuvant treatment with tamoxifen and were regarded as tamoxifen resistant. CIP2A expression was scored separately for cytoplasmic, nuclear, or membranous staining, and scores were tested for statistically significant relationships with clinicopathological features. Membranous CIP2A was preferentially expressed in cases who experienced a recurrence during tamoxifen treatment thus predicting a worse overall survival (log rank = 8.357, p = 0.004) and disease-free survival (log rank = 21.766, p < 0.001). Cox multivariate analysis indicates that it is an independent prognostic indicator for overall survival (hazard ratio = 4.310, p = 0.013) and disease-free survival (hazard ratio = 5.449, p = 0.002). In this study, we propose the assessment of membranous CIP2A expression as a potential novel prognostic and predictive indicator for tamoxifen resistance and recurrence within oestrogen receptor-positive breast cancer.

Breast cancer epidemic in the early twenty-first century: evaluation of risk factors, cumulative questionnaires and recommendations for preventive measures.

Rapidly increasing incidence of breast cancer is a new social challenge resulting from a spectrum of internal and external risk factors which appear to be well accepted as an attribute of the early twenty-first century, being, however, new for female sub-populations compared to the past. These include altered socio-economical conditions such as occupational exposure, rotating shift work, specific environmental factors (increased pollution and environmental toxicity, altered dietary habits, quality and composition of meal) as well as consequently shifted and/or adapted physiologic factors such as lower age at menarche, late age of first full-term pregnancy, if any, shorter periods of breastfeeding and later menopause. Consolidated expert statements suggest that over 50 % of all breast cancer cases may be potentially prevented by risk reduction strategy such as regulation of modifiable risk factors. Currently available risk assessment models may estimate potential breast cancer predisposition, in general; however, they are not able to predict the disease manifestation individually. Further, current deficits in risk assessment and effective breast cancer prevention have been recently investigated and summarised as follows: gaps in risk estimation, preventive therapy, lifestyle prevention, understanding of the biology of breast cancer risk and implementation of known preventive measures. This paper overviews the most relevant risk factors, provides recommendations for improved risk assessment and proposes an extended questionnaire for effective preventive measures.

Deregulation of the protein phosphatase 2A, PP2A in cancer: complexity and therapeutic options.

The complexity of the phosphatase, PP2A, is being unravelled and current research is increasingly providing information on the association of deregulated PP2A function with cancer initiation and progression. It has been reported that decreased activity of PP2A is a recurrent observation in many types of cancer, including colorectal and breast cancer (Baldacchino et al. EPMA J. 5:3, 2014; Cristobal et al. Mol Cancer Ther. 13:938-947, 2014). Since deregulation of PP2A and its regulatory subunits is a common event in cancer, PP2A is a potential target for therapy (Baldacchino et al. EPMA J. 5:3, 2014). In this review, the structural components of the PP2A complex are described, giving an in depth overview of the diversity of regulatory subunits. Regulation of the active PP2A trimeric complex, through phosphorylation and methylation, can be targeted using known compounds, to reactivate the complex. The endogenous inhibitors of the PP2A complex are highly deregulated in cancer, representing cases that are eligible to PP2A-activating drugs. Pharmacological opportunities to target low PP2A activity are available and preclinical data support the efficacy of these drugs, but clinical trials are lacking. We highlight the importance of PP2A deregulation in cancer and the current trends in targeting the phosphatase.

Immune-related gene methylation prognostic instrument for stratification and targeted treatment of ovarian cancer patients toward advanced 3PM approach.

Background: DNA methylation is an important mechanism in epigenetics, which can change the transcription ability of genes and is closely related to the pathogenesis of ovarian cancer (OC). We hypothesize that DNA methylation is significantly different in OCs compared to controls. Specific DNA methylation status can be used as a biomarker of OC, and targeted drugs targeting these methylation patterns and DNA methyltransferase may have better therapeutic effects. Studying the key DNA methylation sites of immune-related genes (IRGs) in OC patients and studying the effects of these methylation sites on the immune microenvironment may provide a new method for further exploring the pathogenesis of OC, realizing early detection and effective monitoring of OC, identifying effective biomarkers of DNA methylation subtypes and drug targets, improving the efficacy of targeted drugs or overcoming drug resistance, and better applying it to predictive diagnosis, prevention, and personalized medicine (PPPM; 3PM) of OC. Method: Hypermethylated subtypes (cluster 1) and hypomethylated subtypes (cluster 2) were established in OCs based on the abundance of different methylation sites in IRGs. The differences in immune score, immune checkpoints, immune cells, and overall survival were analyzed between different methylation subtypes in OC samples. The significant pathways, gene ontology (GO), and protein-protein interaction (PPI) network of the identified methylation sites in IRGs were enriched. In addition, the immune-related methylation signature was constructed with multiple regression analysis. A methylation site model based on IRGs was constructed and verified. Results: A total of 120 IRGs with 142 differentially methylated sites (DMSs) were identified. The DMSs were clustered into a high-level methylation group (cluster 1) and a low-level methylation group (cluster 2). The significant pathways and GO analysis showed many immune-related and cancer-associated enrichments. A methylation site signature based on IRGs was constructed, including RORC|cg25112191, S100A13|cg14467840, TNF|cg04425624, RLN2|cg03679581, and IL1RL2|cg22797169. The methylation sites of all five genes showed hypomethylation in OC, and there were statistically significant differences among RORC|cg25112191, S100A13|cg14467840, and TNF|cg04425624 (p < 0.05). This prognostic model based on low-level methylation and high-level methylation groups was significantly linked to the immune microenvironment as well as overall survival in OC. Conclusions: This study provided different methylation subtypes for OC patients according to the methylation sites of IRGs. In addition, it helps establish a relationship between methylation and the immune microenvironment, which showed specific differences in biological signaling pathways, genomic changes, and immune mechanisms within the two subgroups. These data provide ones to deeply understand the mechanism of immune-related methylation genes on the occurrence and development of OC. The methylation-site signature is also to establish new possibilities for OC therapy. These data are a precious resource for stratification and targeted treatment of OC patients toward an advanced 3PM approach. Supplementary Information: The online version contains supplementary material available at 10.1007/s13167-024-00359-3.

Digital biomarkers: 3PM approach revolutionizing chronic disease management - EPMA 2024 position.

Non-communicable chronic diseases (NCDs) have become a major global health concern. They constitute the leading cause of disabilities, increased morbidity, mortality, and socio-economic disasters worldwide. Medical condition-specific digital biomarker (DB) panels have emerged as valuable tools to manage NCDs. DBs refer to the measurable and quantifiable physiological, behavioral, and environmental parameters collected for an individual through innovative digital health technologies, including wearables, smart devices, and medical sensors. By leveraging digital technologies, healthcare providers can gather real-time data and insights, enabling them to deliver more proactive and tailored interventions to individuals at risk and patients diagnosed with NCDs. Continuous monitoring of relevant health parameters through wearable devices or smartphone applications allows patients and clinicians to track the progression of NCDs in real time. With the introduction of digital biomarker monitoring (DBM), a new quality of primary and secondary healthcare is being offered with promising opportunities for health risk assessment and protection against health-to-disease transitions in vulnerable sub-populations. DBM enables healthcare providers to take the most cost-effective targeted preventive measures, to detect disease developments early, and to introduce personalized interventions. Consequently, they benefit the quality of life (QoL) of affected individuals, healthcare economy, and society at large. DBM is instrumental for the paradigm shift from reactive medical services to 3PM approach promoted by the European Association for Predictive, Preventive, and Personalized Medicine (EPMA) involving 3PM experts from 55 countries worldwide. This position manuscript consolidates multi-professional expertise in the area, demonstrating clinically relevant examples and providing the roadmap for implementing 3PM concepts facilitated through DBs.

The role of translation initiation regulation in haematopoiesis.

Organisation of RNAs into functional subgroups that are translated in response to extrinsic and intrinsic factors underlines a relatively unexplored gene expression modulation that drives cell fate in the same manner as regulation of the transcriptome by transcription factors. Recent studies on the molecular mechanisms of inflammatory responses and haematological disorders indicate clearly that the regulation of mRNA translation at the level of translation initiation, mRNA stability, and protein isoform synthesis is implicated in the tight regulation of gene expression. This paper outlines how these posttranscriptional control mechanisms, including control at the level of translation initiation factors and the role of RNA binding proteins, affect hematopoiesis. The clinical relevance of these mechanisms in haematological disorders indicates clearly the potential therapeutic implications and the need of molecular tools that allow measurement at the level of translational control. Although the importance of miRNAs in translation control is well recognised and studied extensively, this paper will exclude detailed account of this level of control.

PKC-mediated phosphorylation and activation of the MEK/ERK pathway as a mechanism of acquired trastuzumab resistance in HER2-positive breast cancer.

Protein expression, activation and stability are regulated through inter-connected signal transduction pathways resulting in specific cellular states. This study sought to differentiate between the complex mechanisms of intrinsic and acquired trastuzumab resistance, by quantifying changes in expression and activity of proteins (phospho-protein profile) in key signal transduction pathways, in breast cancer cellular models of trastuzumab resistance. To this effect, we utilized a multiplex, bead-based protein assay, DigiWest®, to measure around 100 proteins and protein modifications using specific antibodies. The main advantage of this methodology is the quantification of multiple analytes in one sample, utilising input volumes of a normal western blot. The intrinsically trastuzumab-resistant cell line JIMT-1 showed the largest number of concurrent resistance mechanisms, including PI3K/Akt and RAS/RAF/MEK/ERK activation, ß catenin stabilization by inhibitory phosphorylation of GSK3ß, cell cycle progression by Rb suppression, and CREB-mediated cell survival. MAPK (ERK) pathway activation was common to both intrinsic and acquired resistance cellular models. The overexpression of upstream RAS/RAF, however, was confined to JIMT 1; meanwhile, in a cellular model of acquired trastuzumab resistance generated in this study (T15), entry into the ERK pathway seemed to be mostly mediated by PKCα activation. This is a novel observation and merits further investigation that can lead to new therapeutic combinations in HER2-positive breast cancer with acquired therapeutic resistance.

A randomized, controlled trial on the effect of anesthesia on chronic pain after total knee arthroplasty.

Aim: The study sought to evaluate the influence of anesthesia on chronic pain after total knee arthroplasty (TKA). Methods: This was a single-center, randomized controlled study, with patients receiving a spinal anesthetic (SP) alone or a general anesthetic (GA) with femoral block, with follow-up at 3 and at 6 months. The primary outcome was the WOMAC® score at 6 months. Results: 199 patients were enrolled. Group SP had better function (WOMAC: GA: 16.9 vs SP: 14.4, p = 0.015) and less pain (WOMAC pain: GA: 3.04 vs SP: 2.69, p = 0.02) at 3 months, but not at 6 months. Overall, 11% of patients had chronic postsurgical pain (CPSP), with Group GA having a higher incidence of CPSP at 6 months. Neuropathic pain increased during the follow-up and was more common in patients with CPSP. Conclusion: An SP reduces pain and incidence of CPSP after TKA. Clinical Trial Registration: NCT04206046 (ClinicalTrials.gov).

Patients who have knee replacement surgery are at risk of remaining in significant pain even up to one year after surgery. Our study aims to look into the potential of reducing this risk by comparing two common forms of anesthesia. 199 patients were randomized to either have a spinal anesthetic (SP) or a general anesthetic with a femoral nerve block. Patients were then followed-up for 6 months, and then asked to report on a validated functional and pain scoring system (WOMAC^®). Patients who had had an SP had better function and less pain at 3 months after surgery, but not at 6 months. The incidence of chronic pain at six month seems to be less with an SP.

Differential Expression of the Sphingolipid Pathway Is Associated with Sensitivity to the PP2A Activator FTY720 in Colorectal Cancer Cell Lines.

Protein phosphatase 2A (PP2A) is a ubiquitously expressed intracellular serine/threonine phosphatase. Deregulation of PP2A is a common event associated with adenocarcinomas of the colon and rectum. We have previously shown that breast cancer cell lines are sensitive to the PP2A activator FTY720, and that sensitivity is predicted by high Aurora kinase A (AURKA) mRNA expression. In this study, we hypothesized that high relative AURKA expression could predict sensitivity to FTY720-induced apoptosis in colorectal cancer (CRC). The CRC cell lines NCI H716, COLO320DM, DLD-1, SW480, and HT-29 show a high relative AURKA expression as compared to LS411N, T84, HCT116, SW48, and LOVO. Following viability assays, LS411N, T84, HCT116, and SW480 were shown to be sensitive to FTY720, whereas DLD-1 and HT-29 were non-sensitive. Hence, AURKA mRNA expression does not predict sensitivity to FTY720 in CRC cell lines. Differentially expressed genes (DEGs) were obtained by comparing the sensitive CRC cell lines (LS411N and HCT116) against the non-sensitive (HT-29 and DLD-1). We found that 253 genes were significantly altered in expression, and upregulation of CERS4, PPP2R2C, GNAZ, PRKCG, BCL2, MAPK12, and MAPK11 suggests the involvement of the sphingolipid signaling pathway, known to be activated by phosphorylated-FTY720. In conclusion, although AURKA expression did not predict sensitivity to FTY720, it is evident that specific CRC cell lines are sensitive to 5 µM FTY720, potentially because of the differential expression of genes involved in the sphingolipid pathway.

Igbp1 is part of a positive feedback loop in stem cell factor-dependent, selective mRNA translation initiation inhibiting erythroid differentiation.

Stem cell factor (SCF)-induced activation of phosphoinositide-3-kinase (PI3K) is required for transient amplification of the erythroblast compartment. PI3K stimulates the activation of mTOR (target of rapamycin) and subsequent release of the cap-binding translation initiation factor 4E (eIF4E) from the 4E-binding protein 4EBP, which controls the recruitment of structured mRNAs to polysomes. Enhanced expression of eIF4E renders proliferation of erythroblasts independent of PI3K. To investigate which mRNAs are selectively recruited to polysomes, we compared SCF-dependent gene expression between total and polysome-bound mRNA. This identified 111 genes primarily subject to translational regulation. For 8 of 9 genes studied in more detail, the SCF-induced polysome recruitment of transcripts exceeded 5-fold regulation and was PI3K-dependent and eIF4E-sensitive, whereas total mRNA was not affected by signal transduction. One of the targets, Immunoglobulin binding protein 1 (Igbp1), is a regulatory subunit of protein phosphatase 2A (Pp2a) sustaining mTOR signaling. Constitutive expression of Igbp1 impaired erythroid differentiation, maintained 4EBP and p70S6k phosphorylation, and enhanced polysome recruitment of multiple eIF4E-sensitive mRNAs. Thus, PI3K-dependent polysome recruitment of Igbp1 acts as a positive feedback mechanism on translation initiation underscoring the important regulatory role of selective mRNA recruitment to polysomes in the balance between proliferation and maturation of erythroblasts.

Tissue-specific splicing factor gene expression signatures.

The alternative splicing code that controls and coordinates the transcriptome in complex multicellular organisms remains poorly understood. It has long been argued that regulation of alternative splicing relies on combinatorial interactions between multiple proteins, and that tissue-specific splicing decisions most likely result from differences in the concentration and/or activity of these proteins. However, large-scale data to systematically address this issue have just recently started to become available. Here we show that splicing factor gene expression signatures can be identified that reflect cell type and tissue-specific patterns of alternative splicing. We used a computational approach to analyze microarray-based gene expression profiles of splicing factors from mouse, chimpanzee and human tissues. Our results show that brain and testis, the two tissues with highest levels of alternative splicing events, have the largest number of splicing factor genes that are most highly differentially expressed. We further identified SR protein kinases and small nuclear ribonucleoprotein particle (snRNP) proteins among the splicing factor genes that are most highly differentially expressed in a particular tissue. These results indicate the power of generating signature-based predictions as an initial computational approach into a global view of tissue-specific alternative splicing regulation.

The landscape of genomic copy number alterations in colorectal cancer and their consequences on gene expression levels and disease outcome.

Aneuploidy, the unbalanced state of the chromosome content, represents a hallmark of most solid tumors, including colorectal cancer. Such aneuploidies result in tumor specific genomic imbalances, which emerge in premalignant precursor lesions. Moreover, increasing levels of chromosomal instability have been observed in adenocarcinomas and are maintained in distant metastases. A number of studies have systematically integrated copy number alterations with gene expression changes in primary carcinomas, cell lines, and experimental models of aneuploidy. In fact, chromosomal aneuploidies target a number of genes conferring a selective advantage for the metabolism of the cancer cell. Copy number alterations not only have a positive correlation with expression changes of the majority of genes on the altered genomic segment, but also have effects on the transcriptional levels of genes genome-wide. Finally, copy number alterations have been associated with disease outcome; nevertheless, the translational applicability in clinical practice requires further studies. Here, we (i) review the spectrum of genetic alterations that lead to colorectal cancer, (ii) describe the most frequent copy number alterations at different stages of colorectal carcinogenesis, (iii) exemplify their positive correlation with gene expression levels, and (iv) discuss copy number alterations that are potentially involved in disease outcome of individual patients.

Aspirin impairs acetyl-coenzyme A metabolism in redox-compromised yeast cells.

Aspirin is a widely used anti-inflammatory and antithrombotic drug also known in recent years for its promising chemopreventive antineoplastic properties, thought to be mediated in part by its ability to induce apoptotic cell death. However, the full range of mechanisms underlying aspirin's cancer-preventive properties is still elusive. In this study, we observed that aspirin impaired both the synthesis and transport of acetyl-coenzyme A (acetyl-CoA) into the mitochondria of manganese superoxide dismutase (MnSOD)-deficient Saccharomyces cerevisiae EG110 yeast cells, but not of the wild-type cells, grown aerobically in ethanol medium. This occurred at both the gene level, as indicated by microarray and qRT-PCR analyses, and at the protein level as indicated by enzyme assays. These results show that in redox-compromised MnSOD-deficient yeast cells, but not in wild-type cells, aspirin starves the mitochondria of acetyl-CoA and likely causes energy failure linked to mitochondrial damage, resulting in cell death. Since acetyl-CoA is one of the least-studied targets of aspirin in terms of the latter's propensity to prevent cancer, this work may provide further mechanistic insight into aspirin's chemopreventive behavior with respect to early stage cancer cells, which tend to have downregulated MnSOD and are also redox-compromised.

Translation initiation factor 4E inhibits differentiation of erythroid progenitors.

Stem cell factor (SCF) delays differentiation and enhances the expansion of erythroid progenitors. Previously, we performed expression-profiling experiments to link signaling pathways to target genes using polysome-bound mRNA. SCF-induced phosphoinositide-3-kinase (PI3K) appeared to control polysome recruitment of specific mRNAs associated with neoplastic transformation. To evaluate the role of mRNA translation in the regulation of expansion versus differentiation of erythroid progenitors, we examined the function of the eukaryote initiation factor 4E (eIF4E) in these cells. SCF induced a rapid and complete phosphorylation of eIF4E-binding protein (4E-BP). Overexpression of eIF4E did not induce factor-independent growth but specifically impaired differentiation into mature erythrocytes. Overexpression of eIF4E rendered polysome recruitment of mRNAs with structured 5' untranslated regions largely independent of growth factor and resistant to the PI3K inhibitor LY294002. In addition, overexpression of eIF4E rendered progenitors insensitive to the differentiation-inducing effect of LY294002, indicating that control of mRNA translation is a major pathway downstream of PI3K in the regulation of progenitor expansion.

Optimization of a Multiplex RNA-based Expression Assay Using Breast Cancer Archival Material.

Nucleic acid degradation in archival tissue, tumor heterogeneity, and a lack of fresh frozen tissue specimens can negatively impact cancer diagnostic services in pathology laboratories worldwide. Gene amplification and expression diagnostic testing using archival material or material that requires transportation to servicing laboratories, needs a more robust and accurate test adapted to current clinical workflows. Our research team optimized the use of Invitrogen™ QuantiGene™ Plex Assay (Thermo Fisher Scientific) to quantify RNA in archival material using branched-DNA (bDNA) technology on Luminex xMAP® magnetic beads. The gene expression assay described in this manuscript is a novel, quick, and multiplex method that can accurately classify breast cancer into the different molecular subtypes, omitting the subjectivity of interpretation inherent in imaging techniques. In addition, due to the low input of material required, heterogeneous tumors can be laser microdissected using Hematoxylin and Eosin (H&E) stained sections. This method has a wide range of possible applications including tumor classification with diagnostic potential and measurement of biomarkers in liquid biopsies, which would allow better patient management and disease monitoring. In addition, the quantitative measurement of biomarkers in archival material is useful in oncology research with access to libraries of clinically-annotated material, in which retrospective studies can validate potential biomarkers and their clinical outcome correlation.