Cancer Drug Resistance
Cancer Drug Resistance is a quarterly published journal committed to the rapid publication of high quality, peer-reviewed, original research. The journal publishes research articles, reviews, case reports, commentaries and letters on pharmacological aspects of drug resistance and its reversal, including drug design, drug delivery, drug distribution and cellular drug resistance. Molecular mechanisms of drug resistance also cover the cellular pharmacology of drug resistance such as influx and efflux pumps (including the ABC pumps), receptors and their ligands, cellular signaling pathways, drug activation and degradation (including Phase I and II metabolism), drug sequestration, target modification and DNA repair. Drug classes involved include DNA targeted drugs and antihormones as well as antibodies and protein kinase inhibitors. Both clinical and experimental aspects of drug resistance in cancer are included.
Welcome to visit our homepage at https://cdrjournal.com/
Supervisors: Godefridus J. Peters, Editor-in-Chief, [email protected] and Bill Li, Managing Editor, [email protected]
Welcome to visit our homepage at https://cdrjournal.com/
Supervisors: Godefridus J. Peters, Editor-in-Chief, [email protected] and Bill Li, Managing Editor, [email protected]
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Papers by Cancer Drug Resistance
Methods: Peripheral blood mononuclear cells from four healthy donors were challenged with a 1-week exposure to whole-cell lysate from CMV-infected cells or CMVpp65495-503 peptide (NLVPMVATV). T-cell repertoire perturbations were assessed using the Oncomine TCR Beta-SR Assay and Ion GeneStudio S5 Plus Sequencer. A pp65 tetramer flow cytometry assay was used as an orthogonal method to assess clonal expansion of a subset of CMV-specific T-cells. For evaluation of the assay in peripheral blood lymphocytes from NSCLC donors, five whole blood specimens were evaluated using the same sequencing workflow.
Results: The TCR beta assay identified 6,683-61,936 unique clones from 1-2 million reads per sample, and an average of 80% of the total reads were usable for TCR profiling. In the NSCLC donors, TCR convergence and clonality values were consistent with published results and ranged 0.016-0.033 for convergence and 0.09-0.48 for clonality. In the CMV study, TCR sequencing detected the expansion of a common family of clones in all 4 samples in response to antigen stimulation. This expansion corresponded to an increase in pp65 tetramer staining by flow cytometry. Baseline TCR convergence scores ranged 0.009-0.041 and increased 5-fold in one sample as a result of pp65 antigen stimulation.
Conclusion: The results of this study demonstrated the utility of profiling of the TCRβ repertoire in a model system and in donors with NSCLC. Additionally, we demonstrated the correlation between RNA-seq methods and protein-tetramer analysis using flow cytometry. These techniques represent an emerging solution that could complement other liquid and tissue diagnostic assays in the clinic and will be of value in predicting host response/resistance and adverse events to immunotherapies. Prospective clinical studies are on-going in which the developed TCR beta assay will undergo further validation.
Methods: Using western blotting and flow cytometry, we sought to determine whether MEKi affects JAK-STAT signaling upstream of PD-L1 and MHC-I expression in a panel of mouse mammary cancer and triple negative breast cancer cell lines.
Results: The cell lines tested exhibited increased STAT activation in response to MEKi treatment. Furthermore, MEKi-induced MHC-I and PD-L1 expression are dependent upon STAT1 in MMTV-Neu cells. Interestingly, MEKi-induced STAT activation and interferon-responsive protein expression are abrogated with ErbB-family inhibitor co-treatment in MMTV-Neu cells, suggesting ErbB receptor signaling dependence, but not in basal-like cell lines. Importantly, analysis of basal-like breast cancer patient samples exhibited an inverse relationship between STAT1 and Ras/MAPK activation signatures.
Conclusion: These findings suggest that MAPK signaling and STAT activation are inversely related in both mouse and human mammary tumors. This work also supports further study of MEKi to increase STAT signaling and potentially, immunotherapy responses through increased MHC-I and PD-L1 expression.
Methods: Anti-proliferative and apoptotic-inducing effects of Nef and Dox combination in Parental and Dox resistant lung cancer cells were determined in monolayers and 3D spheroids. Intracellular Dox was analyzed using flow cytometry, siRNA knockdown and western blot analysis were used to elucidate NRF2-LRP crosstalk mechanism.
Results: We observed that the Dox resistant lung cancer cells expressed higher levels of LRP, reduced glutathione (GSH) and NRF2. Combination of Dox and Nef induced apoptosis, leads to reactive oxygen species (ROS) generation, GSH depletion and reduction in LRP levels contributing to higher intracellular and intranuclear Dox accumulation. The use of N-acetylcysteine and knockdown studies confirmed an important role of ROS and NRF2 in LRP down regulation. Presence of NRF2 binding sites in LRP is support of direct interaction between LRP and NRF2.
Conclusion: Nef sensitizes lung cancer cells to Dox by increasing intracellular and/or intra nuclear Dox accumulation via LRP down regulation. This is mediated by redox regulating NRF2. This decoded crosstalk mechanism reinforces the role of NRF2 and LRP in Dox resistance and as an important anticancer target.
Methods: We isolated CTCs using negative CD45+ depletion and subjected them to multiplex confocal microscopy using our established protocol. CTCs were identified as CD45-/CK+/DAPI+ cells and MT-DTE was determined using our developed imaging algorithm. We quantified MT bundling in CTCs across multiple time points, from baseline to on-treatment to disease progression. Here, we describe the longitudinal analysis of MT-DTE in CTCs from patients treated with CRXL301 and its correlation with response to treatment.
Results: We collected CTCs at seven time points from three metastatic castration-resistant prostate cancer patients. Clinical response was evaluated by Response Evaluation Criteria in Solid Tumors (RECIST) v.1.1 criteria in those patients with measurable disease. Of the three patients enrolled, one experienced partial response (-50%) to CRXL301 and two patients were unevaluable given bone only disease. Notably, however, these two patients showed stable disease clinically based on bone scans. MT-DTE across all time points revealed that, early time points within four and 24 h of drug administration exhibited the highest levels of drug engagement (MT-DTE) as compared to baseline. However, these early time points did not correlate with clinical response. We observed that the CTCs collected one week after the first or second dose of CRXL301 treatment in the responding patient had numerically higher levels of MT-DTE as compared to the other two patients.
Conclusion: Taxane on-target activity can be detected and analyzed quantitatively in CTCs by tubulin immunofluorescence. Early time points, within 24 h of drug administration, showed high levels of DTE but did not correlate with clinical response. MT-DTE in CTCs collected after one week on treatment correlated best with treatment response. The clinical utility of the 1-week CTC DTE should be tested and validated in future clinical trials involving taxanes.