Monitoring Of Tumor Cells Research Articles

ATP-activated Fe(Ⅲ)/carbon dots assemblies for in situ generating nanozyme and simultaneously monitoring tumor cell ferroptosis

The integration of nanomedicine and nanocatalysis has currently resulted in the emergence of synthesized nanozymes with disruptive potential in alternative cancer therapy. However, the in situ synthesis of nanozymes using an intracellular components remains a formidable challenge. In this study, the inactivated Fe(Ⅲ)/carbon dots nanoassemblies (Fe/CDs-A) were prepared through Fe3+-induced assembly of red emissive CDs. In tumor cells overexpressing adenosine triphosphate (ATP), Fe/CDs-A can be activated and disassembled, causing the specific release of CDs and simultaneous formation of Fe3+-ATP nanocomplexes in situ due to the enhanced coordination between intracellular ATP and Fe3+. Intriguingly, Fe3+-ATP nanocomplexes were found to possess peroxidase (POD)-like activity, efficiently generating highly toxic •OH in the presence of acidic H2O2 in tumor cells, thereby inducing tumor cells ferroptosis. Simultaneously, the released CDs initially penetrate the lysosomes of tumor cells and ultimately accumulate in the nuclei of dead/dying cells, achieving real-time monitoring cell death process through their recovered red emission. Overall, for the first time, the well-designed Fe/CDs-A demonstrates its capability as ATP-triggered inducers for in situ generation of nanozymes and specific release of CDs. This study offers a novel pathway for in situ generation of nanozymes for precise cancer therapy.

Characterization of tumor evolution by functional clonality and phylogenetics in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a molecularly heterogeneous solid malignancy, and its fitness may be shaped by how its tumor cells evolve. However, ability to monitor tumor cell evolution is hampered by the presence of numerous passenger mutations that do not provide any biological consequences. Here we develop a strategy to determine the tumor clonality of three independent HCC cohorts of 524 patients with diverse etiologies and race/ethnicity by utilizing somatic mutations in cancer driver genes. We identify two main types of tumor evolution, i.e., linear, and non-linear models where non-linear type could be further divided into classes, which we call shallow branching and deep branching. We find that linear evolving HCC is less aggressive than other types. GTF2IRD2B mutations are enriched in HCC with linear evolution, while TP53 mutations are the most frequent genetic alterations in HCC with non-linear models. Furthermore, we observe significant B cell enrichment in linear trees compared to non-linear trees suggesting the need for further research to uncover potential variations in immune cell types within genomically determined phylogeny types. These results hint at the possibility that tumor cells and their microenvironment may collectively influence the tumor evolution process.

H2S-activated fluorescent probe enables dual-channel fluorescence tracking of drug release in tumor cells

Nowadays, the selective release of therapeutic drugs into tumor cells has become an important way of tumor treatment due to the high side effects of chemotherapy drugs. As one of the gas mediators, hydrogen sulfide (H2S) is closely related to cancer. Due to the high content of H2S in tumor cells, it can be used as a signaling molecule that triggers the release of drugs to achieve the selective release of therapeutic drugs. In addition, dual-channel fluorescence imaging technology can be better applied to monitor the drug delivery process and distinguish the state before and after drug release, so as to better track the effect of drug therapy. Based on this, we used NBD amines (NBD-NHR) as the recognition group of H2S and connected the tyrosine kinase inhibitor crizotinib to construct an activated dual-channel fluorescent probe CZ-NBD. After the probe enters the tumor cells, it consumes H2S and releases crizotinib, which is highly toxic to the tumor cells. Importantly, the probe displays significant fluorescence changes in different cells, enabling not only the screening of tumor cells, but also tracking and monitoring drug release and tumor cell activity. Therefore, the construction of probe CZ-NBD provides a new strategy for drug release monitoring in tumor cells.

Clinical utility of circulating tumor cells for real-time serial monitoring of nasopharyngeal carcinoma patients

Clinical utility of circulating tumor cells for real-time serial monitoring of nasopharyngeal carcinoma patients

On-Cell Catalytic Detection of Epithelial-to-Mesenchymal Transition by a Clusterzyme Bioprobe.

We construct a peptide-conjugated metal cluster as an enzyme-like catalytic bioprobe to enhance quantitative analysis of a membrane protein biomarker and detect epithelial-to-mesenchymal transition of tumor cells. This bioprobe with atomically precise formula, termed clusterzyme, possesses selective recognition and intrinsic enzyme-like activity. These favorable features facilitate sensitive quantitative analysis of the membrane protein in situ through on-cell catalytic signal amplification. This clusterzyme-based analytical method exhibits excellent compatibility with a traditional enzyme-linked immunosorbent assay and improved detection sensitivity with accuracy and robustness. Further, the expression level of the membrane protein reflects the ability of migration and invasion of model tumor cells, revealing epithelial-to-mesenchymal transition process. This work offers a facile and sensitive approach to monitor tumor cell type evolution at the molecular level, demonstrating a potential application of early cancer diagnosis and therapy assessment.

Protocols for the Evaluation of a Lymphatic Drug Delivery System Combined with Bioluminescence to Treat Metastatic Lymph Nodes.

Bioluminescence (BL) imaging is a powerful non-invasive imaging modality widely used in a broad range of biological disciplines for many types of measurements. The applications of BL imaging in biomedicine are diverse, including tracking bacterial progression, research on gene expression patterns, monitoring tumor cell growth/regression or treatment responses, determining the location and proliferation of stem cells, and so on. It is particularly valuable when studying tissues at depths of 1 to 2cm in mouse models during preclinical research. Here we describe the protocols for the therapeutic evaluation of a lymphatic drug delivery system (LDDS) using an in vivo BL imaging system (IVIS) for the treatment of metastatic lymph nodes (LNs) with 5-fluorouracil (5-FU). The LDDS is a method that directly injects anticancer drugs into sentinel LNs (SLNs) and delivers them to their downstream LNs. In the protocol, we show that metastases in the proper axillary LN (PALN) are induced by the injection of luciferase-expressing tumor cells into the subiliac LN (SiLN) of MXH10/Mo-lpr/lpr (MXH10/Mo/lpr) mice. 5-FU is injected using the LDDS into the accessory axillary LN (AALN) to treat tumor cells in the PALN after the tumor cell growth is confirmed in the PALN. The tumor growth and therapeutic effects are evaluated by IVIS. This method can be used to evaluate tumor growth and efficacy of anticancer drugs/particles, radiotherapy, surgery, and/or a combination of these methods in various experimental procedures in the oncology field.

Establishment of an optimized CTC detection model consisting of EpCAM, MUC1 and WT1 in epithelial ovarian cancer and its correlation with clinical characteristics.

ObjectiveEmerging studies have demonstrated the promising clinical value of circulating tumor cells (CTCs) for diagnosis, disease assessment, treatment monitoring and prognosis in epithelial ovarian cancer. However, the clinical application of CTC remains restricted due to diverse detection techniques with variable sensitivity and specificity and a lack of common standards.MethodsWe enrolled 160 patients with epithelial ovarian cancer as the experimental group, and 90 patients including 50 patients with benign ovarian tumor and 40 healthy females as the control group. We enriched CTCs with immunomagnetic beads targeting two epithelial cell surface antigens (EpCAM and MUC1), and used multiple reverse transcription-polymerase chain reaction (RT-PCR) detecting three markers (EpCAM, MUC1 and WT1) for quantification. And then we used a binary logistic regression analysis and focused on EpCAM, MUC1 and WT1 to establish an optimized CTC detection model.ResultsThe sensitivity and specificity of the optimized model is 79.4% and 92.2%, respectively. The specificity of the CTC detection model is significantly higher than CA125 (92.2% vs. 82.2%, P=0.044), and the detection rate of CTCs was higher than the positive rate of CA125 (74.5% vs. 58.2%, P=0.069) in early-stage patients (stage I and II). The detection rate of CTCs was significantly higher in patients with ascitic volume ≥500 mL, suboptimal cytoreductive surgery and elevated serum CA125 level after 2 courses of chemotherapy (P<0.05). The detection rate of CTCEpCAM+ and CTCMUC1+ was significantly higher in chemo-resistant patients (26.3% vs. 11.9%; 26.4% vs. 13.4%, P<0.05). The median progression-free survival time for CTCMUC1+ patients trended to be longer than CTCMUC1− patients, and overall survival was shorter in CTCMUC1+ patients (P=0.043). ConclusionsOur study presents an optimized detection model for CTCs, which consists of the expression levels of three markers (EpCAM, MUC1 and WT1). In comparison with CA125, our model has high specificity and demonstrates better diagnostic values, especially for early-stage ovarian cancer. Detection of CTCEpCAM+ and CTCMUC1+ had predictive value for chemotherapy resistance, and the detection of CTCMUC1+ suggested poor prognosis.

Screening immunotherapy cancer drugs in a scalable, physiologically relevant 3D in vitro tumor microenvironment model

Abstract Interaction of tumor cells with surrounding stromal and immune cells, secreted cytokines, and extracellular matrix proteins, collectively known as the tumor microenvironment (TME), is crucial for cancer progression and metastasis. Here, we present a novel 3D in vitro TME model to assess candidate drugs for cancer therapy. For this study, we prepared lung carcinoma spheroids from GFP-A549 cells co-cultured with cancer-associated fibroblasts (CAFs) and PBMCs. To simulate a pro-inflammatory tumor microenvironment, we activated PBMCs with cytokines and/or anti-CD3/CD28. We assessed the effect of PD-1 inhibitors in combination with cytokines for potential synergistic anti-cancer effects. We then developed a tumor model using melanoma PDX cells labeled with CellTracker to monitor tumor cell viability after exposure to activated PBMCs. We evaluated killing activity and effector function of T cells by measuring tumor microtissue size by automatic stage fluorescence microscopy and release of IL-6, TNFa, IFNγ and GM-CSF with a MAGPIXTM Luminex system over time. Immune cell infiltration and its effects on tumor were assessed by histological analysis using tumor, immune cell and apoptosis markers. Our results show combination treatment with cytokines and anti-PD-1 antibody led to higher secretion of IL-6/TNFa/IFNγ/GM-CSF, reduced tumor size, increased infiltration of the model by CD8+ T cells, stronger expression of Granzyme B resulting in enhanced tumor apoptosis and killing. This confirms our novel 3D in vitro TME model is a promising tool for studying cell-cell interactions and allows for HCS of novel candidates for anti-cancer drugs.

Longitudinal Immunogenomic Profiling of Tumor and Immune Cells for Minimally-Invasive Monitoring of Smoldering Multiple Myeloma (SMM): The Immunocell Study

Longitudinal Immunogenomic Profiling of Tumor and Immune Cells for Minimally-Invasive Monitoring of Smoldering Multiple Myeloma (SMM): The Immunocell Study

Determination of the optimal detection time of circulating tumor cells for the postoperative monitoring of colorectal cancer.

Circulating tumor cells (CTCs) are widely used in cancer screening and monitoring. The present study focused on investigating the optimal time for the postoperative CTC detection in patients with colorectal cancer (CRC) to obtain more accurate results and facilitate subsequent treatment. By subtraction enrichment immunofluorescence in situ hybridization detection of CTCs, the present study demonstrated that different postoperative detection times in CRC substantially influenced the CTC numbers. In total, 134 subjects were enrolled. Among 10 healthy individuals and 20 preoperative patients with CRC, no CTCs were identified in the healthy subjects, and CTCs were detected in 85% (17/20) of the preoperative patients. In total, 104 postoperative patients with CRC (53 males and 51 females) with a mean average age of 57.63 years were studied. The total CTC detection rate was 81.73% (85/104) and the mean average CTC numbers in patients with tumor stage (T) T1, T2, T3 and T4 were 4.00, 3.33, 5.90 and 5.64 per 7.50 ml of peripheral blood, respectively. The CTC number trends in these four tumor stages within 5, 6, 7 and 10 postoperative days were variable, and were the most stable at 7 days. Gradual upward trends in CTC numbers were observed after 5, 6 and 7 postoperative days, and this upward trend was more obvious after 7 days. Overall, the findings of the present study suggest that CTC detection in CRC should be performed after at least 7 postoperative days rather than within 7 postoperative days.

A siRNA-based method for efficient silencing of PYROXD1 gene expression in the colon cancer cell line HCT116.

The aim of this study was to determine the biological function of pyridine nucleotide-disulfide oxidoreductase domain 1 (PYROXD1), a recently discovered protein, in colon cancer cell line HCT116. The small interfering RNA (siRNA) was designed rationally on the basis of the target sequence against PYROXD1. Relative PYROXD1 mRNA levels were measured by aquantitative real-time polymerase chain reaction. Flow cytometry was performed to monitor tumor cells proliferation and apoptosis after siRNA transfection. Knockdown of PYROXD1arrested the cell cycle, and induced late apoptosis in colon cancer cell line HCT116 DISCUSSION: Taken together, these results revealed the critical roles of PYROXD1 in regulating cell cycle and apoptosis and possibly will signify its therapeutic potential for targeting colorectal cancer models.

Fluorescence monitoring of rare circulating tumor cell and cluster dissemination in a multiple myeloma xenograft model in vivo.

.Circulating tumor cells (CTCs) are of great interest in cancer research because of their crucial role in hematogenous metastasis. We recently developed “diffuse in vivo flow cytometry” (DiFC), a preclinical research tool for enumerating extremely rare fluorescently labeled CTCs directly in vivo. In this work, we developed a green fluorescent protein (GFP)-compatible version of DiFC and used it to noninvasively monitor tumor cell numbers in circulation in a multiple myeloma (MM) disseminated xenograft mouse model. We show that DiFC allowed enumeration of CTCs in individual mice overtime during MM growth, with sensitivity below of peripheral blood. DiFC also revealed the presence of CTC clusters (CTCCs) in circulation to our knowledge for the first time in this model and allowed us to calculate CTCC size, frequency, and kinetics of shedding. We anticipate that the unique capabilities of DiFC will have many uses in preclinical study of metastasis, in particular, with a large number of GFP-expressing xenograft and transgenic mouse models.

Abstract 4317: Application of gene methylation analysis for distinguishing primary tumor cells from normal epithelial cells from lung cancer patients in conditionally reprogrammed cell cultures

Abstract In vitro drug sensitivity assays utilizing “conditionally reprogrammed cells” (CRCs) from different primary tumor types to guide personalized therapy has been emerging. However, this approach has been hindered by the growth of normal epithelial cells in CRC cultures and the lack of effective biomarkers/assays to distinguish them from primary tumor cells. In this study, we developed a DNA methylation-based, real-time PCR assay to investigate the methylation status of SHOX2,PTGER4 and Septin9 gene promotor regions in human lung cancer formalin fixed paraffin-embedded (FFPE) samples. Our results showed increased DNA methylation for at least one of the three genes in 90% (28/31) of tumor samples as compared with the corresponding adjacent normal samples. Then we tested gene methylation in fresh surgical tumors versus normal adjacent tissues from lung cancer patients, and their respective in vitro CRC cultures. Increased methylation for at least one of the three genes was detected in 91.6% of tumor samples (11/12) as compared with the adjacent tissues, and these positive methylation statuses were maintained in 75% (9/12) of CRC cultures. Further results from in vitro assays showed a correlation between higher cell methylation status and increased growth property in 3D culture, as well as differential response to chemotherapy. Together, our results demonstrated that methylation of SHOX2, PTGER4 and Septin9 genes can be used as reliable biomarkers to monitor tumor cells in in vitro CRC cultures. Citation Format: Guodong Wu, Yangui Xiao, Fuyuan Fang, Da Yao, Ji Liu, Yanhua Cao, Yu Mao, Benjamin Yu, Youhui Qian, Derek Yu. Application of gene methylation analysis for distinguishing primary tumor cells from normal epithelial cells from lung cancer patients in conditionally reprogrammed cell cultures [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4317.

Abstract 4970: Establishment of a patient-derived platform for preclinical immunooncology studies using autologous tumor and TIL coculture

Abstract The use of tumor infiltrated lymphocytes (TILs) as an adoptive cell transfer therapy to treat cancer has been conducted in clinic trials for more than two decades. TIL therapy in combination with added immunotherapy treatments, such as IL-2 or anti-CTLA4, has further improved clinical response rates. Isolated from a patient’s own tumor specimen, TILs that recognizes tumor-specific known or unknown antigens can be expanded and infused back to tumor-bearing patients to attack autologous cancer cell populations. Despite the progress in clinical research, preclinical and translational models of autologous tumor/TIL coculture have been difficult to establish. This study has established autologous tumor/TIL coculture methods directly from patient tumor specimens. Models were established from BioDuro’s viably cryopreserved tumor &amp; TIL bank, containing more than 100,000 patient biospecimens. Each patient specimen contains a heterogeneous population of cells types, including tumor, TILs and TAFs (tumor associated fibroblasts). These cell populations were expanded under specific growth conditions to then serve as components for the patient-derived coculture systems established. In this study, TILs and monocytes from a cohort of patient tumor specimens (including kidney, melanoma and lung) were analyzed. Leukocytes, T cells, monocytes and B cells were marked with CD45, CD3, CD14, CD20. Patients’ samples were also tested for PD-1 expression levels. The results show significant individual variation on cell subpopulations and PD-1 expression. Established methods were used for expansion of TILs, supporting either CD4 or CD8 phenotypes. Autologous cancer cells were expanded at the same time. TILs and tumor cells were co-cultured and high content fluorescent image cytometry was used to monitor tumor cell killing. This study found that autologous patient-matched TILs showed preferential tumor cell killing compared to patient-unmatched TILs. This response was observed in a dose dependent fashion. In summary, the BioDuro biobank of viable tumor and TIL patient specimens served as a large and powerful immunooncology resource to establish patient-derived autologous tumor/TIL coculture assays. These assays, and the ability to readily study larger populations of cancer patients, provide a powerful in vitro platform to test immunooncology drug candidates. Citation Format: Kaede Hinada, Dennis Garland, Dileep Nair, Yong Hu, Thomas Broudy. Establishment of a patient-derived platform for preclinical immunooncology studies using autologous tumor and TIL coculture [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4970.

Circulating tumor cells (CTCs) for the noninvasive monitoring and personalization of non-small cell lung cancer (NSCLC) therapies.

Growing evidences for tumor heterogeneity confirm that single-tumor biopsies frequently fail to reveal the widespread mutagenic profile of tumor. Repeated biopsies are in most cases unfeasible, especially in advanced cancers. We describe here how circulating tumor cells (CTCs) isolated from minimally invasive blood sample might inform us about intratumor heterogeneity, tumor evolution and treatment resistance. We also discuss the advances of CTCs research, most notably in molecularly selected non-small cell lung cancer (NSCLC) patients, highlighting challenges and opportunities related to personalized therapy.

In vivo anticancer activities of Ni (II)-Benzoin thiosemicarbazone complex [Ni(BTSC)2] against ehrlich ascites carcinoma cells

Cancer is a class of diseases in which a group of cells display uncontrolled growth, invasion and sometimes metastasis. In order to find out a new anticancer drug, Ni(II) complex with benzoin thiosemicarbazon was synthesized and characterized. Anticancer activities of Ni(BTSC)2 2 2 has been studied against Ehrlich Ascites Carcinoma (EAC) cells in Swiss albino mice by monitoring tumor cell growth inhibition, tumor weight measurement, survival time of tumor bearing Swiss albino mice. Hematological parameters were also studied in both normal and EAC bearing treated mice. The results were compared with those obtained with a standard anticancer drug bleomycin and the compound was found to possess pronounced anticancer effect. Maximum cell growth inhibition was found to be 77.15% after treatment with Ni(BTSC)2 at the dose of 8 mg/kg (i.p). About 69.56% enhancement of life span was found at 8 mg/kg (i.p).With the same dose Ni(BTSC)2 reduced the tumor weight by 52.17% at day 20. The hematological parameters (WBC, RBC, hemoglobin content and differential counts) were found to be significantly changed as compared to those of the normal mice. These parameters restored more or less towards normal when treated with the test compound.J. bio-sci. 23: 77-88, 2015

Early Assessment of Lung Cancer Immunotherapy Response via Circulating Tumor DNA.

Purpose: Decisions to continue or suspend therapy with immune checkpoint inhibitors are commonly guided by tumor dynamics seen on serial imaging. However, immunotherapy responses are uniquely challenging to interpret because tumors often shrink slowly or can appear transiently enlarged due to inflammation. We hypothesized that monitoring tumor cell death in real time by quantifying changes in circulating tumor DNA (ctDNA) levels could enable early assessment of immunotherapy efficacy.Experimental Design: We compared longitudinal changes in ctDNA levels with changes in radiographic tumor size and with survival outcomes in 28 patients with metastatic non-small cell lung cancer (NSCLC) receiving immune checkpoint inhibitor therapy. CtDNA was quantified by determining the allele fraction of cancer-associated somatic mutations in plasma using a multigene next-generation sequencing assay. We defined a ctDNA response as a >50% decrease in mutant allele fraction from baseline, with a second confirmatory measurement.Results: Strong agreement was observed between ctDNA response and radiographic response (Cohen's kappa, 0.753). Median time to initial response among patients who achieved responses in both categories was 24.5 days by ctDNA versus 72.5 days by imaging. Time on treatment was significantly longer for ctDNA responders versus nonresponders (median, 205.5 vs. 69 days; P < 0.001). A ctDNA response was associated with superior progression-free survival [hazard ratio (HR), 0.29; 95% CI, 0.09-0.89; P = 0.03], and superior overall survival (HR, 0.17; 95% CI, 0.05-0.62; P = 0.007).Conclusions: A drop in ctDNA level is an early marker of therapeutic efficacy and predicts prolonged survival in patients treated with immune checkpoint inhibitors for NSCLC. Clin Cancer Res; 24(8); 1872-80. ©2018 AACR.

Probing the biophysical properties of tumor cells during mitosis by atomic force microscopy.

Mitosis is an important physiological event accompanying with dramatic changes of cellar biophysical properties. Failure of mitosis results in cell death or chromosome aneuploidy. In this study, we used atomic force microscopy to probe and compare the biophysical properties of tumor cells at different stages during mitosis. The rounding forces of MCF-7 cells oscillated during mitosis. At anaphase, the average elasticity of cells was higher than that at other phases. Cholesterol depletion with M[Formula: see text]CD led to an increase in the average elasticity, whereas the average roughness of membrane surface decreased at the absence of cholesterol. Our study indicated that the distribution of actin filaments could affect the biophysical properties of tumor cells and cellular morphology during mitosis. Furthermore, the biophysical properties of tumor cells were also regulated by membrane cholesterol during mitosis. This work provides a new detection approach for monitoring tumor cell development at single cell level.

Cerebrospinal fluid circulating tumor cells (CSF CTC) for real-time patient monitoring and response to treatment.

11549 Background: The validated CellSearch system (Janssen Diagnostics, LLC), utilizing an immunomagnetic CTC selection method based on EPCAM antibody conjugated ferroparticles, is an FDA-approved methodology for enumerating CTC from blood in pts with breast, prostate and colon cancers. The CellSearch system has been used to evaluate CSF CTC of pts with leptomeningeal metastasis (LM) and has demonstrated potential as a diagnostic marker and response to cancer treatment. We explored the use of CSF CTC enumeration in the follow-up of pts with LM from HER2+ cancers receiving intrathecal (IT) therapy, aimed at characterizing changes over time as a potential biomarker of treatment response. Methods: CSF from pts participating in an IRB-approved phase I/II dose escalation trial of IT trastuzumab for LM in HER2+ cancer (NCT01325207) was evaluated by CellSearch system. 3 ml CSF from a ventricular reservoir was collected for CSF CTC enumeration at pre-treatment Day 1 of each cycle and correlated with CSF cytology from the same sample, and with clinical and radiographic response. LM progression was defined as clinical, CSF cytologic or radiographic worsening. Results: 15 pts with HER2+ LM (14 breast, 1 colon) were enrolled; 13 were women. At baseline 7 pts had positive CSF cytology, the other patients had a diagnosis by MRI. Of the 15 pts, 10 had greater than 1 cycle of treatment to be evaluable; 5 pts progressed during cycle 1 (Table). Mean CSF CTC at baseline was 82 per 3ml (range 0-200); 2 pts had no detectable CSF CTCs. A numerical decrease in CSF CTC was observed in 5 pts after cycle 1 and remained low (mean =9.5, range 0-92) while disease was stable. 3 pts (pts.3, 4 and 7) demonstrated a rise in CSF CTCs roughly 1 month prior to disease progression. Conclusions: Changes in CSF CTCs enumeration in response to treatment may allow quantitative surveillance of treatment response. CSF CTCs may serve as a platform to assess treatment response or as an early biomarker of LM progression and should be further investigated. Clinical trial information: NCT01325207. [Table: see text]

Spatial concordance of tumor proliferation and accelerated repopulation from pathologic images to 18F-FLT PET images.

e23100 Background: PET imaging with 18F-fluorothymidine (18F-FLT) can potentially be used to identify tumor subvolumes for selecting dose escalation in radiation therapy. The aim of this study was to monitor tumor cell proliferation and repopulation during fractionated radiotherapy and investigated the spatial concordance of tumor cell proliferation and repopulation with 18F-FLT tracer uptake. Methods: Mice bearing A549 xenograft tumors were assigned to 5 different irradiated groups (3f/6d, 6f/12d, 9f/18d, 12f/24d and 18f/36d) with 2 Gy/fractions and non-irradiated group. Serial 18F-FLT micro PET scans were performed at different time points, the maximum of standard uptake value (SUVmax) were measured to detect the feasible time of tumor repopulation during irradiation. Ex vivo images of the spatial pattern of intratumor 18F-FLT uptake and Ki-67 labeling index (LI) were obtained from thin tumor tissue sections. A layer-by-layer comparison between SUVmax and Ki-67 LI results, including the thresholds at which maximum overlap occurred between FLT-segmented areas and areas of active cell proliferation, were conducted to evaluate the spatial imaging pathology correlation. Results: The SUVmax were observed decreases in the 3f/6d group (P = 0.000), compared to these for non-irradiated tumors. However, it was significantly increased in the 6f/12d later, and then gradually reduced with treatment time prolonged again after 6f/12d group. Proliferation changes on pathology imaging at 6f/12d were also confirmed. Significant correlations were found between the SUVmax and Ki-67 LI of all ROIs in each in vitro tumor of cell proliferation group (Ps &lt; 0.001). Similar results were also found in each tumor of accelerated repopulation group (Ps &lt; 0.001). Furthermore, both of the mean ORRs were more than 50% in all layer of the tumor cell proliferation and accelerated groups. Regions of high-intensity 18F-FLT uptake in the autoradiographs exhibited prominent staining for Ki-67. Conclusions: 18F-FLT PET may be a promising imaging surrogate of tumor proliferative response to fractionated radiotherapy and might help make adaptive radiation oncology treatment plan.