In mammalian cells, cytotoxic stress triggers several signaling cascades that converge in the phosphorylation of translation initiation factor 2α, shuttling of nuclear RNA-binding proteins such as ...TIA-1 to the cytoplasm, and aggregation of most cellular mRNAs into TIA-1-containing stress granules (SGs). As a result, protein synthesis is greatly impaired. Here we describe different dynamics of endogenous transcripts according to their cellular location, in response to stress. While cytosolic mRNAs aggregate into SGs, endoplasmic reticulum (ER) -bound transcripts escape sequestration. This has been specifically demonstrated using the multidrug resistance transporter gene (MDR1) as a model and showing that chimeric RNA constructs can be directed to the cytosol or tethered to the ER depending on the nature of the chimera, in response to stress. In addition, polysome profile analyses indicate that, on stress, ribosomes do not disengage from ER-associated transcripts (puromycin insensitive) and recover their translation status faster than SG-targeted cytosolic mRNAs once the stress is lifted. These findings have important implications for cell survival given that many membrane proteins, which are translated at the ER, have important roles in detoxification.--Unsworth, H., Raguz, S., Edwards, H. J., Higgins, C. F., Yagüe, E. mRNA escape from stress granule sequestration is dictated by localization to the endoplasmic reticulum.
MicroRNAs (miRNAs) have critical roles in regulating cancer cell survival, proliferation and sensitivity to chemotherapy. The potential application of using miRNAs to predict chemotherapeutic ...response to cancer treatment is highly promising. However, the underlying mechanisms of chemotherapy response control by miRNAs remain to be fully identified and their prognostic value has not been fully evaluated. Here we show a strong correlation between miR-205 expression and chemosensitivtiy to TAC (docetaxol, doxorubicin plus cyclophosphamide), a widely-used neoadjuvant chemotherapy (NAC) regimen, for breast cancer patients. High level of miR-205 predicted better response to TAC regimen NAC in breast cancer patients. We found miR-205 downregulated in both MCF-7/A02 and CALDOX cells, two drug-resistant derivatives of MCF-7 and Cal51 cells, and its ectopic expression led to an increase in apoptosis resensitization of both drug-resistant cell lines to doxorubicin and taxol. We further show that miR-205 directly binds VEGFA and FGF2 mRNA 3'-UTRs and confirm that miR-205 levels are negatively correlated with VEGFA and FGF2 mRNA expression in breast cancer patients. Adding VEGFA and FGF2 exogenously to chemosensitive breast cancer cells and chemoresistant cells with miR-205 overexpression led to drug resistance. Consistently, low VEGFA and FGF2 expression correlated with better response to NAC in breast cancer patients. In addition, inhibition of tumor growth and resensitization to doxorubicin were also observed in mouse tumor xenografts from cells overexpressing miR-205. Taken together, our data suggest that miR-205 enhances chemosensitivity of breast cancer cells to TAC chemotherapy by suppressing both VEGFA and FGF2, leading to evasion of apoptosis. MiR-205 may serve as a predictive biomarker and a potential therapeutic target in breast cancer treatment.
FOXM1 is implicated in genotoxic drug resistance but its mechanism of action remains elusive. We show here that FOXM1-depletion can sensitize breast cancer cells and mouse embryonic fibroblasts ...(MEFs) into entering epirubicin-induced senescence, with the loss of long-term cell proliferation ability, the accumulation of γH2AX foci, and the induction of senescence-associated β-galactosidase activity and cell morphology. Conversely, reconstitution of FOXM1 in FOXM1-deficient MEFs alleviates the accumulation of senescence-associated γH2AX foci. We also demonstrate that FOXM1 regulates NBS1 at the transcriptional level through an forkhead response element on its promoter. Like FOXM1, NBS1 is overexpressed in the epirubicin-resistant MCF-7Epi(R) cells and its expression level is low but inducible by epirubicin in MCF-7 cells. Consistently, overexpression of FOXM1 augmented and FOXM1 depletion reduced NBS1 expression and epirubicin-induced ataxia-telangiectasia mutated (ATM)phosphorylation in breast cancer cells. Together these findings suggest that FOXM1 increases NBS1 expression and ATM phosphorylation, possibly through increasing the levels of the MRN(MRE11/RAD50/NBS1) complex. Consistent with this idea, the loss of P-ATM induction by epirubicin in the NBS1-deficient NBS1-LBI fibroblasts can be rescued by NBS1 reconstitution. Resembling FOXM1, NBS1 depletion also rendered MCF-7 and MCF-7Epi(R) cells more sensitive to epirubicin-induced cellular senescence. In agreement, the DNA repair-defective and senescence phenotypes in FOXM1-deficent cells can be effectively rescued by overexpression of NBS1. Moreover, overexpression of NBS1 and FOXM1 similarly enhanced and their depletion downregulated homologous recombination (HR) DNA repair activity. Crucially, overexpression of FOXM1 failed to augment HR activity in the background of NBS1 depletion, demonstrating that NBS1 is indispensable for the HR function of FOXM1. The physiological relevance of the regulation of NBS1 expression by FOXM1 is further underscored by the strong and significant correlation between nuclear FOXM1 and total NBS1 expression in breast cancer patient samples, further suggesting that NBS1 as a key FOXM1 target gene involved in DNA damage response, genotoxic drug resistance and DNA damage-induced senescence.
Resistance to cancer chemotherapeutic treatment is a common phenomenon, especially in progressive disease. The generation of cellular models of drug resistance has been pivotal in unravelling the ...main effectors of resistance to traditional chemotherapy at the molecular level (i.e. intracellular drug inactivation, detoxifying systems, defects in DNA repair, apoptosis evasion, membrane transporters and cell adhesion). The development of targeted therapies has also been followed by resistance, reminiscent of an evolutionary arms race, as exemplified by imatinib and other BCR-ABL inhibitors for the treatment of chronic myelogenous leukaemia. Although traditionally associated with the last stages of the disease, recent findings with minimally transformed pretumorigenic primary human cells indicate that the ability to generate drug resistance arises early during the tumorigenic process, before the full transformation. Novel technologies, such as genome profiling, have in certain cases predicted the outcome of chemotherapy and undoubtedly have tremendous potential for the future. In addition, the novel cancer stem cell paradigm raises the prospect of cell-targeted therapies instead of treatment directed against the whole tumour.
Background:
Biologic or targeted synthetic disease modifying antirheumatic drugs (b/tsDMARD) may be stopped for several reasons such as non-response, adverse events, remission, or other reasons (e.g. ...major surgery). Understanding the reasons and consequences of b/tsDMARD therapy cessation may contribute towards therapy decision guidance. Moreover, identifying patient characteristics leading to the re-start of b/tsDMARD therapy may guide decision-making as to which patients should remain on continuous b/tsDMARD therapy versus who may potentially stop b/tsDMARD therapy.
Objectives:
To describe and follow rheumatoid arthritis (RA) patients who stopped b/tsDMARD therapy, stratified by cessation reason.
Methods:
We conducted a descriptive cohort study among adult RA patients in the longitudinal Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) between 1997 and 2019. RA patients who stopped their first b/tsDMARD therapy were eligible, with therapy stop date defining cohort entry. We followed all eligible patients from cohort entry until b/tsDMARD re-start (the outcome) or censoring due to end of patient record. All analyses were carried out stratified by cessation reason (non-response, adverse events, remission, other reasons, unknown reasons). We described patient characteristics (demographics, lifestyle factors, clinical information, other medication use, relevant comorbidities) at cohort entry. Furthermore, we estimated Kaplan Meier curves to describe differences in cumulative incidences of b/tsDMARD re-start. Finally, we assessed patient characteristics at b/tsDMARD re-start and compared them with those at cohort entry.
Results:
Among 2559 eligible RA patients, the majority stopped their b/tsDMARD due to non-response (982, 38%), followed by adverse events (475, 19%), other reasons (445, 17%), unknown reasons (444, 17%), and remission (213, 8%). Mean age at b/tsDMARD stop was around 56.2 years except in patients who stopped due to remission (mean age of 58.1 years). The majority of patients were women (78%), stopping due to an adverse event had the highest proportion of women (84%), stopping due to remission had the lowest proportion of women (70%). Compared to patients who stopped b/tsDMARD therapy due to non-response or adverse events, patients who stopped due to remission were generally more physically active, better educated, less likely to have a family history of rheumatic diseases, and had shorter median disease duration. A total of 2086 patients (82%) re-started b/tsDMARD therapy during follow-up. Of these, the majority did so after stopping due to non-response (94%), followed by adverse events (82%), unknown reasons (79%), other reasons (74%), and remission (47%). The median cumulative incidence of re-starting b/tsDMARD therapy was shortest after non-response (30 days), followed by unknown reasons (31 days), adverse events (94 days), other reasons (212 days), and remission (1597 days). The population who stopped b/tsDMARD therapy due to remission or other reasons yielded increased RA disease activity and an increase in proportions of women, cardiac diseases, degenerative joint disease, other auto-immune diseases, and of patients with family history of rheumatic diseases at the date of b/tsDMARD re-start. However, among patients who stopped b/tsDMARD therapy due to non-response or adverse events, patient characteristics at b/tsDMARD re-start were unchanged compared to those at b/tsDMARD stop.
Conclusion:
Observed differences in patient characteristics at b/tsDMARD stop may yield insight into why the patient was not responding, had an adverse event, or achieved remission. Observed changes in patient characteristics from the date of b/tsDMARD stop to re-start identified which ones may lead to a worsening of RA activity in the absence of b/tsDMARD therapy.
Acknowledgements:
We would like to thank Dr. Almut Scherer, Monika Hebeisen, and Eleftherios Papagiannoulis from SCQM for providing the data and answering questions thereto. A list of rheumatology offices and hospitals that are contributing to the SCQM registries can be found on
www.scqm.ch/institutions
. The SCQM is financially supported by pharmaceutical industries and donors. A list of financial supporters can be found on
www.scqm.ch/sponsors
.
Disclosure of Interests:
Theresa Burkard: None declared, Enriqueta Vallejo-Yagüe: None declared, Thomas Hügle Consultant of: Pfizer, Abbvie, Novartis, Grant/research support from: GSK, Jansen, Pfizer, Abbvie, Novartis, Roche, MSD, Sanofi, BMS, Eli Lilly, UCB, Axel Finckh Speakers bureau: Pfizer, Eli-Lilly, Paid instructor for: Pfizer, Eli-Lilly, Consultant of: Pfizer, BMS, Novartis, Grant/research support from: AbbVie, AB2Bio, BMS, Gilead, Pfizer, Viatris, Andrea Michelle Burden: None declared
Resistance to chemotherapeutic treatment, which is indirectly responsible for many cancer deaths, is normally associated with an aggressive phenotype including increased cell motility and acquisition ...of invasive properties. Here we describe how breast cancer cells overcome doxorubicin-induced senescence and become drug resistant by overexpression of the microRNA (miR)-106b~25 cluster. Although all three miRs in the cluster contribute to the generation of doxorubicin resistance, miR-25 is the major contributor to this phenotype. All three miRs in this cluster target EP300, a transcriptional activator of E-cadherin, resulting in cells acquiring a phenotype characteristic of cells undergoing epithelial-to-mesenchymal transition (EMT), including an increase in both cell motility and invasion, as well as the ability to proliferate after treatment with doxorubicin. These findings provide a novel drug resistance/EMT regulatory pathway controlled by the miR-106b~25 cluster by targeting a transcriptional activator of E-cadherin.
Overexpression of P-glycoprotein, encoded by the MDR1 gene, confers multidrug resistance (MDR) on cancer cells and is a frequent impediment to successful chemotherapy. Recent developments in the use ...of small interfering RNAs to inhibit specific protein expression have highlighted their potential use as therapeutic agents. We have expressed two different short hairpin RNAs from stably integrated plasmids in doxorubicin-resistant K562 leukaemic cells. The MDR1-targeted RNA interference (RNAi) resulted in decreased MDR1 mRNA, abolished P-glycoprotein expression, and completely reversed the MDR phenotype to that of the drug-sensitive K562 parental line. This study demonstrates that MDR, which is solely due to overexpression of P-glycoprotein, can be reversed by RNAi. These target sequences can in the future be integrated into gene therapy vectors with potential clinical application.
Current approaches for detecting circulating tumour cells (CTCs) in blood are dependent on CTC enrichment and are based either on surface epithelial markers on CTCs or on cell size differences. The ...objectives of this study were to develop and characterise an ultrasensitive multiplex fluorescent RNA in situ hybridisation (ISH)-based CTC detection system called CTCscope. This method detects a multitude of tumour-specific markers at single-cell level in blood.
Healthy blood samples spiked with tumour cell lines were used as a model system for the development and initial characterisation of CTCscope. To demonstrate the feasibility of CTC detection in patient blood, duplicate blood samples were drawn from 45 metastatic breast cancer patients for analysis by CTCscope and the CellSearch system. The association of CTCs with the tumour marker CA15-3 and progression-free survival (PFS) were assessed.
CTCscope detected CTC transcripts of eight epithelial markers and three epithelial-mesenchymal-transition (EMT) markers for increased sensitivity. CTCscope was used to detect CTCs with minimal enrichment, and did not detect apoptotic or dead cells. In patient blood samples, CTCs detected by CellSearch, but not CTCscope, were positively correlated with CA15-3 levels. Circulating tumour cells detected by either CTCscope or CellSearch predicted PFS (CTCscope, HR (hazard ratio) 2.26, 95% CI 1.18-4.35, P=0.014; CellSearch, HR 2.50, 95% CI 1.27-4.90, P=0.008).
CTCscope offers unique advantages over existing CTC detection approaches. By enumerating and characterising only viable CTCs, CTCscope provides additional prognostic and predictive information in therapy monitoring.
Drug resistance in cancer Yagüe, E; Raguz, S
British journal of cancer,
10/2005, Volume:
93, Issue:
9
Journal Article, Conference Proceeding
Peer reviewed
Open access
Cancer Research UK has recently sponsored a meeting, organized by the UK Medical Research Council, on cancer drug resistance. Several of the molecular mechanisms responsible for this clinical ...outcome, such as DNA interstrand crosslink repair, apoptosis evasion, cytochrome P450 and P-glycoprotein, were discussed. There was a special focus on leukaemia, breast and ovarian cancer, and the potential use of positron-emission tomography to study anticancer-drug resistance. The progress made in translating these findings to the clinic, like Gefitinib, P-glycoprotein phenotyping, or genome-wide analysis technology, was also discussed.
Background
Among patients with psoriatic arthritis (PsA), obesity is a common comorbidity, and it is associated with difficulted disease management. This may be explained by the understanding of ...obesity as a low-grade inflammatory disease, which shares pathological pathway with PsA.
Objectives
We aimed to assess the impact of elevated body mass index (BMI) on the achievement of successful clinical outcomes in PsA patients within one-year after starting their first biologic or targeted synthetic disease-modifying anti-rheumatic drug (b/tsDMARD).
Methods
This observational cohort study was performed using data from the Swiss Clinical Quality Management in Rheumatic Diseases (SCQM) registry (from 1997 to July 31
st
2019), and it included adult PsA patients starting their first b/tsDMARD. Patients were classified according to their BMI as normal weight (BMI <25), overweight (BMI 25.0-29.9), and obese (BMI ≥30). Overweight and obese patients were compared to the normal weight group (reference group). Logistic regression (crude and adjusted by confounders) was used to assess the impact of elevated BMI category on the achievement of clinical outcomes at ≤12-months after start of the patient’s first b/tsDMARD. These clinical outcomes included Minimal Disease Activity (MDA), as well as remission defined by Disease Activity for Psoriatic Arthritis (DAPSA), clinical DAPSA, and 28-joint disease activity score (DAS28). Similarly, the likelihood of treatment persistence at one year was compared between the overweight and obese groups
vs
the normal weight group. Additionally, the overlapping or accordance across the study outcomes was investigated.
Results
The study included 306 (39.53%) normal weight, 285 (36.82%) overweight, and 183 (23.64%) obese patients. Compared to the normal weight group, obese patients had lower odds of achieving MDA at ≤12-months (Adjusted odds ratio ORadj 0.45, 95% confidence interval CI 0.24-0.82). This was consistent with the observed reduced odds of achieving DAPSA remission (ORadj 0.42, 95%CI 0.21-0.85), clinical DAPSA remission (ORadj 0.51, 95%CI 0.27-0.96), and DAS28 remission (ORadj 0.51, 95%CI 0.32-0.81) in obese
vs
normal weight patients. No differences were observed in treatment persistence across the BMI strata. And there was high overlap between achievement of MDA and clinical DAPSA remission.
Conclusion
Among PsA patients starting b/tsDMARDs, obesity was associated with ca. 50% reduced odds of achieving MDA and remission in comparison to normal weight patients, while it did not impact treatment persistence.
Acknowledgements
We thank all patients and rheumatologists contributing to the SCQM registry, as well as the entire SCQM staff. A list of rheumatology offices and hospitals which contribute to the SCQM registry can be found at
http://www.scqm.ch/institutions
. A list of financial supporters of SCQM can be found at
http://www.scqm.ch/sponsors
. We would like to add a personal thank you to Axel Finckh (University Hospitals of Geneva) for his input regarding the database. AMB acknowledges that her professorship is partly endowed by the Swiss National Pharmacy Association (PharmaSuisse) and the ETH Foundation.
Disclosure of Interests
None declared
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