Using plasma cell-free DNA to monitor the chemoradiotherapy course of cervical cancer.

The liquid biopsy is being integrated into cancer diagnostics and surveillance. However, critical questions still remain, such as how to precisely evaluate cancer mutation burden and interpret the corresponding clinical implications. Herein, we evaluated the role of peripheral blood cell-free DNA (cfDNA) in characterizing the dynamic mutation alterations of 48 cancer driver genes from cervical cancer patients. We performed targeted deep sequencing on 93 plasma cfDNA from 57 cervical cancer patients and from this developed an algorithm, allele fraction deviation (AFD), to monitor in an unbiased manner the dynamic changes of genomic aberrations. Differing treatments, including chemotherapy (n = 22), radiotherapy (n = 14) and surgery (n = 15), led to a significant decrease in AFD values (Wilcoxon, p = 0.029). The decrease of cfDNA AFD values was accompanied by shrinkage in the size of the tumor in most patients. However, in a subgroup of patients where cfDNA AFD values did not reflect a reduction in tumor size, there was a detection of progressive disease (metastasis). Furthermore, a low AFD value at diagnosis followed a later increase of AFD value also successfully predicted relapse. These results show that plasma cfDNA, together with targeted deep sequencing, may help predict treatment response and disease development in cervical cancer.

Target-triggered enzyme-free amplification strategy for sensitive detection of microRNA in tumor cells and tissues.

MicroRNAs (miRNAs) participate in important processes of life course. Because of their characters of small sizes, vulnerable degradabilities, and sequences similarities, the existing detection technologies mostly contain enzymatic amplification reactions for acquisition of high sensitivities and specificities. However, specific reaction conditions and time-dependent enzyme activities are caused by the accession of enzymes. Herein, we designed a target-triggered enzyme-free amplification platform that is realized by circulatory interactions of two hairpin probes and the integrated electrochemiluminescence (ECL) signal giving-out component. Benefiting from outstanding performances of the enzyme-free amplification system and ECL, this strategy is provided with a simplified reaction process, high sensitivity, and operation under isothermal conditions. Through detection of the miRNA standard substance, the sensitivity of this platform reached 10 fmol, and a splendid specificity was achieved. We also analyzed three tumor cell lines (human lung adenocarcinoma, breast adenocarcinoma, and hepatocellular liver carcinoma cell lines) through this platform. The sensitivities of 10(3) cells, 10(4) cells, and 10(4) cells were, respectively, achieved. Furthermore, clinical tumor samples were tested, and 21 of 30 experimental samples gave out positive signals. Thus, this platform possesses potentials to be an innovation in miRNA detection methodology.

Targeted deep sequencing from multiple sources demonstrates increased NOTCH1 alterations in lung cancer patient plasma.

INTRODUCTION: Targeted therapies are based on specific gene alterations. Various specimen types have been used to determine gene alterations, however, no systemic comparisons have yet been made. Herein, we assessed alterations in selected cancer-associated genes across varying sample sites in lung cancer patients. MATERIALS AND METHODS: Targeted deep sequencing for 48 tumor-related genes was applied to 153 samples from 55 lung cancer patients obtained from six sources: Formalin-fixed paraffin-embedded (FFPE) tumor tissues, pleural effusion supernatant (PES) and pleural effusion cell sediments (PEC), white blood cells (WBCs), oral epithelial cells (OECs), and plasma. RESULTS: Mutations were detected in 96% (53/55) of the patients and in 83% (40/48) of the selected genes. Each sample type exhibited a characteristic mutational pattern. As anticipated, TP53 was the most affected sequence (54.5% patients), however this was followed by NOTCH1 (36%, across all sample types). EGFR was altered in patient samples at a frequency of 32.7% and KRAS 10.9%. This high EGFR/ low KRAS frequency is in accordance with other TCGA cohorts of Asian origin but differs from the Caucasian population where KRAS is the more dominant mutation. Additionally, 66% (31/47) of PEC samples had copy number variants (CNVs) in at least one gene. Unlike the concurrent loss and gain in most genes, herein NOTCH1 loss was identified in 21% patients, with no gain observed. Based on the relative prevalence of mutations and CNVs, we divided lung cancer patients into SNV-dominated, CNV-dominated, and codominated groups. CONCLUSIONS: Our results confirm previous reports that EGFR mutations are more prevalent than KRAS in Chinese lung cancer patients. NOTCH1 gene alterations are more common than previously reported and reveals a role of NOTCH1 modifications in tumor metastasis. Furthermore, genetic material from malignant pleural effusion cell sediments may be a noninvasive manner to identify CNV and participate in treatment decisions.

Synergistic induction of apoptosis by salinomycin and gefitinib through lysosomal and mitochondrial dependent pathway overcomes gefitinib resistance in colorectal cancer.

Here, we showed the antibiotic salinomycin (SAL) combined with GEF exerted synergistic cytotoxicity effects in colorectal cancer cells irrespective of their EGFR and KRAS status, with a relatively low toxicity to normal cells. Additionally, combination of the two drugs overcame Ras-induced resistance and the acquired resistance to GEF. Further, we identified a new potential mechanism of this cooperative interaction by showing that GEF and SAL acted together to enhance production of reactive oxygen species (ROS), loss of mitochondrial membrane potential (MMP) and lysosomal membrane potential (LMP). And the ROS contributed the loss of MMP and LMP. We also found that GEF and SAL acted in concert to induce apoptosis via a mitochondrial-lysosomal cross-talk and caspase-independent pathway triggered by cathepsin B and D. Lastly, SAL in combination with GEF sensitized GEF-resistant cells to GEF in a nude mouse xenograft model. This novel combination treatment might provide a potential clinical application to overcome GEF resistance in colorectal cancer.

Synthesis, labeling and bioanalytical applications of a tris(2,2'-bipyridyl)ruthenium(II)-based electrochemiluminescence probe.

Assays using probes labeled with electrochemiluminescent moieties are extremely powerful analytical tools that are used in fields such as medical diagnostics, environmental analysis and food safety monitoring, in which sensitive, reliable and reproducible detection of biomolecules is a requirement. The most efficient electrochemiluminescence (ECL) reaction to date is based on tris(2,2'-bipyridyl)ruthenium(II) (Ru(bpy)3(2+)) with tripropylamine (TPrA) as the co-reactant. Here we present a detailed protocol for preparing Ru(bpy)3(2+) probes and their bioanalytical applications. This protocol includes (i) the synthesis of a biologically active Ru(bpy)3(2+)-N-hydroxysuccinimide (NHS) ester, (ii) its covalent labeling with both antibodies and DNA probes and (iii) the detection and quantification of ECL in a microfluidic system with a paramagnetic microbead solid support. In our magnetic bead-based ECL system, two probes are required: a capture probe (labeled with biotin to be captured by a streptavidin-coated magnetic bead) and a detector probe (labeled with Ru(bpy)3(2+)). The complex consisting of the analyte, the capture probe, the detector probe and the magnetic bead is brought into contact with the electrode by using a magnetic field. The Ru(bpy)3(2+) reacts with TPrA in solution to generate the ECL signal. The full protocol, including the synthesis and labeling of the bioactive Ru(bpy)3(2+), requires 5-6 d to complete. ECL immunoassays or nucleic acid tests only require 1.5-2 h, including the sample preparation time.