We have developed and optimized a microfluidic device platform for the capture and analysis of circulating pancreatic cells (CPCs) and pancreatic circulating tumor cells (CTCs). Our platform uses ...parallel anti-EpCAM and cancer-specific mucin 1 (MUC1) immunocapture in a silicon microdevice. Using a combination of anti-EpCAM and anti-MUC1 capture in a single device, we are able to achieve efficient capture while extending immunocapture beyond single marker recognition. We also have detected a known oncogenic KRAS mutation in cells spiked in whole blood using immunocapture, RNA extraction, RT-PCR and Sanger sequencing. To allow for downstream single-cell genetic analysis, intact nuclei were released from captured cells by using targeted membrane lysis. We have developed a staining protocol for clinical samples, including standard CTC markers; DAPI, cytokeratin (CK) and CD45, and a novel marker of carcinogenesis in CPCs, mucin 4 (MUC4). We have also demonstrated a semi-automated approach to image analysis and CPC identification, suitable for clinical hypothesis generation. Initial results from immunocapture of a clinical pancreatic cancer patient sample show that parallel capture may capture more of the heterogeneity of the CPC population. With this platform, we aim to develop a diagnostic biomarker for early pancreatic carcinogenesis and patient risk stratification.
Optimization of pancreatic CTC immunocapture and phenotyping in a microfluidic device.
Hematogenous dissemination is thought to be a late event in cancer progression. We recently showed in a genetic model of pancreatic ductal adenocarcinoma that pancreas cells can be detected in the ...bloodstream before tumor formation. To confirm these findings in humans, we used microfluidic geometrically enhanced differential immunocapture to detect circulating pancreas epithelial cells in patient blood samples. We captured more than 3 circulating pancreas epithelial cells/mL in 7 of 21 (33%) patients with cystic lesions and no clinical diagnosis of cancer (Sendai criteria negative), 8 of 11 (73%) with pancreatic ductal adenocarcinoma, and in 0 of 19 patients without cysts or cancer (controls). These findings indicate that cancer cells are present in the circulation of patients before tumors are detected, which might be used in risk assessment.
Purpose The TAXYNERGY trial ( ClinicalTrials.gov identifier: NCT01718353) evaluated clinical benefit from early taxane switch and circulating tumor cell (CTC) biomarkers to interrogate mechanisms of ...sensitivity or resistance to taxanes in men with chemotherapy-naïve, metastatic, castration-resistant prostate cancer. Patients and Methods Patients were randomly assigned 2:1 to docetaxel or cabazitaxel. Men who did not achieve ≥ 30% prostate-specific antigen (PSA) decline by cycle 4 (C4) switched taxane. The primary clinical endpoint was confirmed ≥ 50% PSA decline versus historical control (TAX327). The primary biomarker endpoint was analysis of post-treatment CTCs to confirm the hypothesis that clinical response was associated with taxane drug-target engagement, evidenced by decreased percent androgen receptor nuclear localization (%ARNL) and increased microtubule bundling. Results Sixty-three patients were randomly assigned to docetaxel (n = 41) or cabazitaxel (n = 22); 44.4% received prior potent androgen receptor-targeted therapy. Overall, 35 patients (55.6%) had confirmed ≥ 50% PSA responses, exceeding the historical control rate of 45.4% (TAX327). Of 61 treated patients, 33 (54.1%) had ≥ 30% PSA declines by C4 and did not switch taxane, 15 patients (24.6%) who did not achieve ≥ 30% PSA declines by C4 switched taxane, and 13 patients (21.3%) discontinued therapy before or at C4. Of patients switching taxane, 46.7% subsequently achieved ≥ 50% PSA decrease. In 26 CTC-evaluable patients, taxane-induced decrease in %ARNL (cycle 1 day 1 v cycle 1 day 8) was associated with a higher rate of ≥ 50% PSA decrease at C4 ( P = .009). Median composite progression-free survival was 9.1 months (95% CI, 4.9 to 11.7 months); median overall survival was not reached at 14 months. Common grade 3 or 4 adverse events included fatigue (13.1%) and febrile neutropenia (11.5%). Conclusion The early taxane switch strategy was associated with improved PSA response rates versus TAX327. Taxane-induced shifts in %ARNL may serve as an early biomarker of clinical benefit in patients treated with taxanes.
Capture and analysis of circulating tumor cells (CTCs) holds promise for diagnosing and guiding treatment of pancreatic cancer. To accurately monitor disease progression, capture platforms must be ...robust to processes that increase the phenotypic heterogeneity of CTCs. Most CTC-analysis technologies rely on the recognition of epithelial-specific markers for capture and identification, in particular the epithelial cell-adhesion molecule (EpCAM) and cytokeratin. As the epithelial-to-mesenchymal transition (EMT) and the acquisition of chemoresistance are both associated with loss of epithelial markers and characteristics, the effect of these processes on the expression of commonly used CTC markers, specifically EpCAM, EGFR and cytokeratin, requires further exploration. To determine this effect, we developed an in vitro model of EMT and acquired gemcitabine resistance in human pancreatic cancer cell lines. Using this model, we show that EMT-induction and acquired chemoresistance decrease EpCAM expression and microfluidic anti-EpCAM capture performance. Furthermore, we find that EGFR capture is more robust to these processes. By measuring the expression of known mediators of chemoresistance in captured cells using automated imaging and image processing, we demonstrate the ability to resistance-profile cells on-chip. We expect that this approach will allow for the development of improved non-invasive biomarkers of pancreatic cancer progression.
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The enrichment and isolation of rare cells from complex samples, such as circulating tumor cells (CTCs) from whole blood, is an important engineering problem with widespread clinical applications. ...One approach uses a microfluidic obstacle array with an antibody surface functionalization to both guide cells into contact with the capture surface and to facilitate adhesion; geometrically enhanced differential immunocapture is a design strategy in which the array is designed to promote target cell–obstacle contact and minimize other interactions (Gleghorn et al.
2010
; Kirby et al.
2012
). We present a simulation that uses capture experiments in a simple Hele-Shaw geometry (Santana et al.
2012
) to inform a target-cell-specific capture model that can predict capture probability in immunocapture microdevices of any arbitrary complex geometry. We show that capture performance is strongly dependent on the array geometry, and that it is possible to select an obstacle array geometry that maximizes capture efficiency (by creating combinations of frequent target cell–obstacle collisions and shear stress low enough to support capture), while simultaneously enhancing purity by minimizing non-specific adhesion of both smaller contaminant cells (with infrequent cell–obstacle collisions) and larger contaminant cells (by focusing those collisions into regions of high shear stress).
We present information on acute stroke care for the first wave of the COVID-19 pandemic in Australia using data from the Australian Stroke Clinical Registry (AuSCR). The first case of COVID-19 in ...Australia was recorded in late January 2020 and national restrictions to control the virus commenced in March. To account for seasonal effects of stroke admissions, patient-level data from the registry from January to June 2020 were compared to the same period in 2019 (historical-control) from 61 public hospitals. We compared periods using descriptive statistics and performed interrupted time series analyses. Perceptions of stroke clinicians were obtained from 53/72 (74%) hospitals participating in the AuSCR (80% nurses)
a voluntary, electronic feedback survey. Survey data were summarized to provide contextual information for the registry-based analysis. Data from the registry covered locations that had 91% of Australian COVID-19 cases to the end of June 2020. For the historical-control period, 9,308 episodes of care were compared with the pandemic period (8,992 episodes). Patient characteristics were similar for each cohort (median age: 75 years; 56% male; ischemic stroke 69%). Treatment in stroke units decreased progressively during the pandemic period (control: 76% pandemic: 70%,
< 0.001). Clinical staff reported fewer resources available for stroke including 10% reporting reduced stroke unit beds. Several time-based metrics were unchanged whereas door-to-needle times were longer during the peak pandemic period (March-April, 2020; 82 min, control: 74 min,
= 0.012). Our data emphasize the need to maintain appropriate acute stroke care during times of national emergency such as pandemic management.
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