CTC together with Shh and Nrf2 are prospective diagnostic markers for HNSCC

BACKGROUND

The lack of appropriate prognostic biomarkers remains a significant obstacle in the early detection of Head and Neck Squamous Cell Carcinoma (HNSCC), a cancer type with a high mortality rate. Despite considerable advancements in treatment, the success in diagnosing HNSCC at an early stage still needs to be improved. Nuclear factor erythroid 2-related factor 2 (Nrf2) and Sonic Hedgehog (Shh) are overexpressed in various cancers, including HNSCC, and have recently been proposed as possible therapeutic targets for HNSCC. Circulating Tumor Cell (CTC) is a novel concept used for the early detection of cancers, and studies have suggested that a higher CTC count is associated with the aggressiveness of HNSCC and poor survival rates. Therefore, we aimed to establish molecular markers for the early diagnosis of HNSCC considering Shh/Nrf2 overexpression in the background. In addition, the relation between Shh/Nrf2 and CTCs is still unexplored in HNSCC patients.

METHODS

In the present study, we selected a cohort of 151 HNSCC patients and categorized them as CTC positive or negative based on the presence or absence of CTCs in their peripheral blood. Data on demographic and clinicopathological features with the survival of the patients were analyzed to select the patient cohort to study Shh/Nrf2 expression. Shh and Nrf2 expression was measured by qRT-PCR.

RESULTS

Considering significant demographic [smoking, betel leaf (p-value < 0.0001)] and clinicopathological risk factors [RBC count (p < 0.05), Platelet count (p < 0.05), Neutrophil count (p < 0.005), MCV (p < 0.0001), NLR (p < 0.05), MLR (p < 0.05)], patients who tested positive for CTC also exhibited significant overexpression of Shh/Nrf2 in both blood and tissue compared to CTC-negative patients. A strong association exists between CTCs and tumor grade. Following chemotherapy (a combination of Cisplatin, 5FU, and Paclitaxel), the frequency of CTCs was significantly decreased in patients with HNSCC who had tested positive for CTCs. The Kaplan-Meier plot illustrated that a higher number of CTCs is associated with poorer overall survival (OS) in patients with HNSCC.

CONCLUSIONS

Detecting CTCs, and higher expression of Shh and Nrf2 in HNSCC patients' blood, can be a promising tool for diagnosing and prognosticating HNSCC.

Role of circulating tumour cells (CTCs) in recurrent/metastatic head and neck squamous cell carcinoma (HNSCC)

Background

Liquid biopsy is emerging as a non-invasive tool, providing a personalized snapshot of a primary and metastatic tumour. It aids in detecting early metastasis, recurrence or resistance to the disease. We aimed to assess the role of circulating tumour cells (CTCs) as a predictive biomarker in recurrent/metastatic head and neck cancer (head and neck squamous cell carcinoma (HNSCC)).

Methodology

Thirty-five patients receiving palliative chemotherapy underwent blood sampling [2 mL in Ethylenediaminetetraacetic acid (EDTA) vial] at baseline and at 3 months intervals. The CTCs were isolated and evaluated using anti-epithelial cell adhesion molecule antibody-based enrichment using the OncoDiscover platform.

Results

CTCs isolated from 80% of patients (n = 28) showed the sensitivity of cell detection at the baseline and 3 months intervals. The median CTC count was 1/1.5 mL of blood and the concordance with clinic-radiological outcomes was 51.4%. The median CTC count (1 (range:0-4) to 0 (range:0-1)) declined at 3 months in responders, while the non-responders had an increase in levels (0 (range :0-2) to 1 (range :0-3)). Although CTCs positively correlated with progression-free survival (PFS) and overall survival (OS), the association of CTCs did not show a significant difference with these parameters (PFS: 6 months versus 4 months; hazard ratio: 0.68; 95% confidence interval (CI): 0.29-1.58, p = 0.323; OS: 10 months versus 8 months; hazard ratio: 0.54; 95% (CI):0.18-1.57 p = 0.216) between CTC positive and CTC negative patients at 3 months.

Conclusion

This study highlights the utility of CTC as a disease progression-monitoring tool in recurrent HNSCC patients. Our findings suggest the potential clinical utility of CTC and the need for exploration in upfront settings of the disease as well (NCT: CTRL/2020/02/023378).

Abstract 6684: Detection of PD-L1, HER2 and EGFR on circulating tumor cells in carcinoma patients

Background: Small molecular inhibitors and immunotherapy has emerged as a novel alternative treatment regime for a variety of epithelial cancers. Large number of clinical trials are in progress to gauge efficacy of tyrosine kinase inhibitors or immune checkpoint inhibitors against actionable targets such as receptor tyrosine kinases and program death ligand 1 (PD-L1). Although highly effective, the outcome of PD-L1 based ICI or TKI against RTKs is vitally contingent on the presence of PD-L1 or RTK expression on circulating tumor cells. We report validation of CTCs with PD-L1, HER2 and EGFR expression in different epithelial cancers.

Methods: We retrospectively evaluated 134 carcinoma patients blood for presence of CTCs expressing PD-L1, HER2 or EGFR markers respect. 45 % patients had lung cancer, while 25 % and 20 % were presented with breast and GI and CRC malignancies. Remaining were gallbladder, ovarian, prostate, and head and neck cancers. CTCs were isolated from DCGI approved OncoDiscover platform with immunomagnetic targeting of EpCAM. CTCs were confirmed with expression of CK18, absence of CD45 and presence of DAPI nucleus. Presence/absence of biomarkers was determined using fluorescence imaging. Expression of PD-L1, HER2 or EGFR was detected by fluorescence microscopy using fluorescently labelled anti PD-L1, HER2 or EGFR antibodies respect. Based on fluorescence intensity CTCs were binned as PD-L1, HER2 or EGFR negative for no detectable fluorescence signal or weakly or strongly positive based on low or high fluorescence signal.

Results: Among the evaluated cohort, 51% of CTCs showed presence of PD-L1 expression. While 63% showed HER2 positive CTCs (breast cancer). 20% from the PD-L1 positive population showed stronger PD-L1 expression. 78% of CTCs from lung cancer patients showed presence of detectable PD-L1 signal, while 66% breast, GI and CRC patients showed CTCs with PD-L1 expression. CTCs from HNC and gall bladder cancer patients showed low PD-L1 expression (25% and 50% respect.). Among CTCs originating from different cancer types, breast cancer CTCs showed higher mean expression of PD-L1 compared to CTCs from CRC patients. A clear subset of CTCs for PD-L1 and Her2 expression was observed in lung and breast cancer patients respect, suggesting the heterogeneity in expression or presence of different subclones within the same tumor type. CTCs evaluated for EGFR expression, 50% showed presence of detectable EGFR compared to the cut-off signal.

Conclusions: CTC can be used as a real-time surrogate for molecular profiling of PD-L1, HER2 and EGFR expression. These CTC cell surface markers offer alternative for immunotherapy or targeted therapies decisions in a adenocarcinomas.

Citation Format: Jayant Khandare, Atul Bharde, Sreeja Jayant, Gourishankar Aland, Meghana Garbhe, Sayali Gosavi, Apoorva Janorkar, Purva Tikekar, Mrunmayi Patil, Vikas Jadhav, Ganesh Khutale, Amrut Ashturkar, Aravindan Vasudevan, Kumar Prabhash, Nirmal Raut, Pankaj Chaturvedi. Detection of PD-L1, HER2 and EGFR on circulating tumor cells in carcinoma patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6684.

Abstract 3379: Comprehensive circulating tumor DNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signature of disease progression

Comprehensive CtDNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signatures of disease progressionBackground: We performed comprehensive ctDNA analysis on early-stage HNC patients in a pilot study to determine the mutational landscape in HNC patients with a known tobacco history. Methods: We analysed ctDNA of 18 early-stage HNC patients for genomic landscapes using the illumina NextSeq 2000 NGS. A custom-designed OncoIndex gene panel was used for the hybrid capture target-enrichment of critical cancer genes. Panel was designed to detect cancer targeting exonic sequence of 600 genes reporting SNVs and indels along fusions and copy number amplification. The gene panel detected genome-wide signatures including bTMB, MSI (microsatellite instability), HRD (homologous recombination deficiency) prediction and calculate cfDNA tumor fraction. Results: 80 % patients showed presence of at least one CTC in peripheral blood, possibly indicating the progressive disease at the time of presentation. Comprehensive genomic profile obtained from plasma cfDNA of early-stage HNC cancer patients predominantly had low bTMB and MSI Scores (99 % patients). However, HRD and LOH matrix was high for 60 % patients indicating highly dysregulated DNA repair activities. Concurring to these observations, 98 % patients had mutations in key tumor suppressor and DNA damage response (DDR) genes possibly resulting in their loss of function. Besides DNA damage pathway, 60% patients harboured alterations in RTK genes including FGFR, EGFR and PDEGFR family and 32% patients showed activating mutations in Erk1 and its upstream regulators. MSH2 was the most prominently mutated gene (37%) followed by FGFR (32%). Surprisingly, unlike HPV positive advanced HNC cases, TP53 mutations were not detected in any patient, though alterations in TS genes were most prevalent in the study population. 51% alterations resulted into truncated proteins possibly impairing their functions, while 42% alterations were point mutations, 6 % were frameshift and 1 % indels. Presence of mutations in BRAF, PDGFR, FGFR and KIT genes suggested for the potential therapy resistance. Tumor fraction representing ctDNA showed elevated range from 20 % to 45 % with a corresponding ploidy between 2 to 4. Conclusions: Comprehensive ctDNA profile showed major gene alterations in TS and DDR response pathway genes besides mutations in proliferative signaling members. TP53 mutation was not detected, although critical tumor suppressor and DDR genes were predominantly mutated, suggesting for a unique mutation pattern associated with early-stage HNC due to tobacco etiology. Our results suggest that comprehensive ctDNA analysis along CTC profiling can predict the disease progression beforehand and may offer new treatment options to early-stage HNC patients.

Citation Format: Gowhar Shafi, Atul Bharde, Fauzul Moubeen, Kanchan Hariramani, Alain D’Souza, Trupti Kad, Bhagwat Jadhav, Sangita Prajapati, Aditi Rani, Madhura Basavalingegowda, Mohan Uttarwar, Gourishankar Aland, Sreeja Jayant, Aravindan Vasudevan, Pankaj Chaturvedi, Jayant Khandare. Comprehensive circulating tumor DNA and CTC profiling of treatment naïve early-stage head and neck cancer patients reveals early signature of disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 3379.

Abstract PR007: Comprehensive ctDNA profiling reveals potential metastatic genomic signatures in treatment-naive early-stage breast cancer patients

Background: Genomic profiling has revolutionized precision oncology impacting the diagnosis, prognosis, and therapy decisions. Considering high spatiotemporal diversity and heterogenicity of breast tumor-cell genomes, small-gene panels often fail to capture rare but important genomic alterations. Conversely, comprehensive ctDNA sequencing approaches enable the identification of under characterized ‘long tailed driver’ genomic alterations and capture Intra and inter metastatic heterogeneity. Here, we demonstrate the clinical utility of comprehensive genome profiling with higher sensitivity to predict the possibility of metastasis in early-stage breast cancer patients. Methods: We retrospectively analyzed ctDNA and genomic DNA (gDNA) from FFPE samples as well as circulating tumor cells (CTC) in 10 treatment-naive hormone positive and HER2 negative, primary-stage breast cancer patients [GS1] using the OncoIndx comprehensive 600 gene panel. The panel captures all important cancer-relevant genomic alterations including Tumor Mutation Burden (TMB), Micro Satellite Instability (MSI), homologous recombination deficiency (HRD) prediction, and cfDNA tumor fraction (TF). CTCs were enumerated from 1.5 ml of blood using the OncoDiscover platform approved by the Drug Controller General of India having anti-EpCAM antibody-mediated immunomagnetic nanoparticles. CTCs were confirmed for cytokeratin 18+ and DAPI + markers and the absence of CD45. Results: Comprehensive genomic profile obtained from ctDNA and gDNA from FFPE of early-stage breast cancer patients predominantly exhibited the presence of alterations in PIK3CA and ESR1 signaling pathways. PIK3CA mutations were present in 77% and 44% of baseline ctDNA and gDNA samples, while ESR1 mutations were present in 44% and 22% of baseline ctDNA and gDNA, respectively. In addition, we observed about 70% additional driver mutations in ctDNA samples suggesting shedding of ctDNA together with CTC (80% positive), a likely positive biomarker of metastasis. About 50% of the patients showed higher TMB and HRD. Notably, TF representing ctDNA varied between 13% to 27% in blood samples with a corresponding ploidy range of 2.9 to 4.7. Surprisingly, ~50% of the patient population matched the mutation profile of clinically confirmed metastatic patients. All the patients harboring potential metastatic driver alterations showed the presence of CTCs in peripheral blood. Conclusions: Comprehensive ctDNA genomic profiling showed potential metastasis driving alterations suggesting the role of ctDNA-based liquid biopsy to predict metastasis in early breast cancer patients. We observed enhanced TF at the time of diagnosis, possibly due to the presence of distant metastasis, high disease burden, and aggressive tumor biology. Our results suggest that ctDNA dynamics at the time of disease presentation can predict early metastasis, and may demonstrate the divergent response of tumor heterogeneity to treatment in early-stage breast cancer.

Citation Format: Gowhar Shafi, Manoj Dongare, Atul Bharde, Moubeen Fauzul, Kanchan Hariramani, Alain D’Souza, Bhagwat Jadhav, Trupti Kad, Sangeeta Prajapati, Vikas Jadhav, ManojKumar Kumaran, Sumit Haldar, Vatsal Mehra, Sujit Joshi, Gourishankar Aland, Richa Dave, Sreeja Jayant, Aravindan Vasudevan, Mohan Uttarwar, Jayant Khandare. Comprehensive ctDNA profiling reveals potential metastatic genomic signatures in treatment-naive early-stage breast cancer patients [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr PR007.

Circulating tumor cells as a predictor for poor prognostic factors and overall survival in treatment naïve oral squamous cell carcinoma patients

OBJECTIVE

The aim of this study was to investigate the presence of circulating tumor cells (CTCs) and their correlation with prognostic factors and clinical outcomes in treatment-naive patients with oral squamous cell carcinoma.

STUDY DESIGN

CTCs were isolated using OncoDiscover technique from presurgically obtained peripheral blood of 152 patients with treatment naïve oral squamous cell carcinoma. Sensitivity analysis was performed by including 40 healthy controls. CTCs cutoff values for clinicopathologic factors were obtained from receiver operating characteristic curves. Multivariate models determined the significance of CTC as independent variables. Kaplan-Meier analysis differentiated in overall survival between CTC values corresponding to the stage.

RESULTS

Sensitivity, specificity, and accuracy of CTC detection were 94.32%, 98%, and 95.17%, respectively. Platform differentiated true positives at >3.5 CTCs (P < .00001). CTCs above 20.5 were suggestive of nodal metastasis (P < .0001) with a linear trend for detecting occult metastasis (P = .061). Early and advanced stages could be differentiated by >13.5 CTCs (P < .0001). Elevated CTCs were significantly associated with extranodal extension (>21.45 CTCs, P = .025), perineural invasion (>19.35 CTCs, P = .049), and depth of invasion (>12.5 CTCs, P = .0038). Median survival was reduced by 19 months when CTCs were >13.

CONCLUSIONS

Preoperative CTC levels demonstrated a strong correlation with adverse clinicopathology factors and suggested its role as a sensitive prognostic marker to predict survival outcome and disease progress.

Machine learning (ML)–enabled, circulating tumor cell–based classification of patients for non-prerequisite adjuvant therapy

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Background: Oncology implicates highest precision using next generation diagnostics and progressive therapies assisted by predictive tools. If validated clinically, machine learning (ML) can provide better insights in precision oncology. Furthermore, it longitudinally may stratify the progression of cancer disease burden in a real time. We have developed, Circulating Tumor Cells (CTCs) driven ML model as a predictor for the treatment decision strategy for both surgery and adjuvant therapy in head and neck squamous cell carcinoma (HNSCC) patients. Methods: In this study, a total of 380 HNSCC patients who underwent either surgery alone or surgery plus adjuvant therapy were accounted for. CTCs in patients were stratified based on clinicopathological parameters and using OncoDiscover platform having anti EpCAM antibody system regulated by the Drug Controller of India. Following this, we explored the predictive performance of the ML model on the usefulness of adjuvant therapy in HNSCC patients after the surgery. The available data was randomly divided into two subsets. First, 75%, of the original data was applied for Training the ML, and rest 25% of the data was used as a Test set. Survival curves were generated by Kaplan–Meier method and calculated through the Log rank test. Results: XGBoost machine learning classifier was superior to Random Forest and SVM-based analyses in predicting the usefulness of adjuvant therapy post-surgery using CTC alone or in combination with other clinical parameters in HNSCC patients. Machine learning algorithms were compared for predicting the accuracy of patients stratification. The results for each model were: XGBoost model (Accuracy = 0.84, ROC value = 0.73, Kappa = 0.43); Random Forest model (Accuracy = 0.81 ROC value = 0.70, Kappa = 0.41); SVM model (Accuracy = 0.76, ROC value = 0. 69, Kappa = 0.40). The ROC value of the XGBoost model was highest (0.73) while the ROC value for the SVM model was lower (0.69). We observed that when CTCs were combined with clinicopathological parameters, the accuracy, kappa values and AUC-ROC drastically improved in predicting the usefulness of adjuvant therapy post-surgery. A similar trend was observed when CTCs were combined with clinicopathological parameters in predicting the line of chemotherapy, post-surgery. Conclusions: ML-enabled, CTCs driven predictions can be highly accurate and ascertain the patient treatments. CTCs can be a positive predictor for selecting patient’s treatment regimen in both surgery as well in type of treatment (e.g. surgery alone or surgery + adjuvant therapy). It can also implicate to classify the patients and determine who necessitates an additional adjuvant therapy. Further investigations in this direction are necessary to predict the treatment options based on ML that may improve the overall survival of cancer patients.

Circulating tumor cells as a biomarker for monitoring: Disease progression, treatment response, and minimal residual disease

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Background: To analyze the role of Circulating tumor cells (CTC) as a confirmatory personalized biomarker for monitoring the disease progression, disease burden, and minimal residual disease in epithelial origin cancers. Methods: In this retrospective study, 127 patients with colorectal, breast, and ovarian cancer at stage III and IV were analyzed. The patients were at various stages of intensive chemo and radiotherapy while the CTCs were isolated and enumerated from 1.5 ml of blood. The decision to continue chemotherapy or change to oral metronomic therapy was based on the presence of circulating tumor cells in Stage III. While in stage IV, serial measurement of CTC guided therapy. CTCs were isolated using OncoDiscover platform possessing EpCAM antibody based immunomagnetic targeting of magnetic nanoparticles after RBC lysis. CTCs were imaged and identified as CK18+ and CD45- cells showing a well-defined nucleus using a motorized fluorescence microscope operational with a monochrome camera. CTCs were enumerated using automated image analysis software and counts were expressed as number per 1.5 ml of blood. Results: In this retrospective study we analyzed blood sample from 127 patients with the advanced stage epithelial cancers (breast- 50 %, ovarian -27 %, colorectal- 23 %) for the presence of CTCs. Amongst those, 52 % showed the presence of CTCs (breast- 52 %, ovarian -46 %, colorectal- 58 %). The CTC count ranged between 1-5 / 1.5 ml of blood with mean and median value of 2 and 1. Among the CTC positive population, majority had CTC count of 1 (44.4 %), while more than 2 CTCs were observed in 11 % of population. CTC clusters were detected in 13 % of population which predominantly were stage IV patients. 67 % among the follow up patients showed decrease in CTC count from the baseline due to the prescribed treatment, while 22 % patients showed increase in CTC count from the baseline. 11 % patients did not show change in CTC count from the baseline. When CTCs count was investigated as an independent variable to monitor the therapeutic response, it correlated well with the positive or negative outcome. In few representative cases, the reduction of CTC number from the basal value was indicative of an effective treatment. Exceptionally, in a representative colorectal cancer case, PET showed no primary as well secondary tumor burden, but the presence of CTCs in blood led further investigating an abdominal MRI that indicated multiple liver lesions suggesting micro-metastasis. Subsequent to SIRT treatment, the patient showed complete tumor regression and absence of CTCs in peripheral blood. Conclusions: Our data suggest that CTC can serve as a dynamic intermittent biomarker for monitoring the disease progression in advanced stages and assess the therapeutic response, thus emphasizing the role of CTCs in personalized cancer management.

Size and Shape Directed Novel Green Synthesis of Plasmonic Nanoparticles Using Bacterial Metabolites and Their Anticancer Effects

The growing need for developing new synthesis methods of plasmonic nanoparticles (PNPs) stems from their various applications in nanotechnology. As a result, a variety of protocols have been developed for the synthesis of PNPs of different shapes, sizes, and compositions. Though widely practiced, the chemical synthesis of PNPs demands stringent control over the experimental conditions, often employs environmentally hazardous chemicals for surface stabilization, and is frequently energy-intensive. Additionally, chemically obtained PNPs require subsequent surface engineering steps for various optoelectronic and biomedicine applications to minimize the toxic effects and render them useful for targeted drug delivery, sensing, and imaging. Considering the pressing need to develop environmentally-friendly technology solutions, “greener” methods of nanoparticle synthesis are gaining importance. Here, we report on the biological synthesis of plasmonic nanoparticles using bacterial metabolites. A peptide-based siderophore pyoverdine and a blue-green pigment pyocyanin obtained from a marine strain of Pseudomonas aeruginosa rapidly produced plasmonic nanoparticles of gold and silver in an aqueous environment. The morphology of plasmonic nanoparticles could be modulated by tuning the concentration of these metabolites and the reaction time. The exposure of pyoverdine to chloroauric acid resulted in anisotropic gold nanoparticles. On the other hand, pyocyanin produced a highly monodispersed population of gold nanoparticles and anisotropic silver nanoparticles. Biologically obtained gold and silver nanoparticles retained pyoverdine and pyocyanin on the nanoparticle surface and were stable for an extended period of time. The biologically obtained gold and silver plasmonic nanoparticles displayed potent anticancer activities against metastatic lung cancer cells. Biogenic nanoparticles were rapidly internalized by cancer cells in high quantity to affect the cellular organization, and karyoplasmic ratio, indicating the potential of these nanoparticles for cancer nanomedicine.

Exploration of intrinsic peroxidase-like activity of Acidithiobacillus ferrooxidans spent medium and its application for glutathione detection

Acidithiobacillus ferrooxidans (At. ferrooxidans) is a bacterium that has the ability to metabolize iron. It converts Fe²⁺ into Fe³⁺ during its metabolic cycle. Hence, the At. ferrooxidans spent medium is rich in Fe³⁺. The presence of Fe³⁺ contributes to a peroxidase-like activity. Therefore, in this study, an attempt has been made to explore the peroxidase-like activity of the At. ferrooxidans spent medium. It has been observed that the At. ferrooxidans spent medium oxidized 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H₂O₂). The effect of various process parameters on the peroxidase-like activity has been studied. Optimum peroxidase-like activity is achieved using 5 µl of the spent medium, 0.3 mM TMB concentration, 4 mM H₂O₂ concentration, 4.2 pH, and 40 °C temperature. The peroxidase-like activity of the At. ferrooxidans spent medium has been used to develop a colorimetric assay for detection of glutathione (GSH). GSH inhibits the peroxidase-like activity of the At. ferrooxidans spent medium in a concentration range of 0-1 mM. The limit of detection (LOD) of GSH, obtained using the calibration plot is 0.69 mM. The developed assay is selective toward GSH, as the presence of amino acids, metals, and sugars have shown a negligible effect on the GSH sensing ability.

Abstract LT014: Extracellular matrix stiffness regulates cellular response to anticancer drugs in breast and lung cancer cells

Physical properties of tumor microenvironment provide key signaling cues that regulate tumorigenic growth of cancer cells. Mechanical properties of tumor microenvironment are principally related to the extracellular matrix (ECM) present around tumor cells. A strong correlation exists between ECM stiffness and tumor growth corroborating the fact that variations in ECM stiffness are vital to regulate metastasis. Though, the effect on ECM stiffness on growth and migration of cancer cells is well documented, its role in regulating cellular response against anticancer drug is relatively unknown. Here we investigated the effect ECM stiffness has on breast (MCF-7) and lung (A549) cancer cells response to conventional as well as non-conventional anticancer phytochemicals at cellular and sub-cellular levels. Using 2D polyacrylamide gels crosslinked to collagen (2D-PA matrix) we probed matrix stiffness dependent cellular responses against clinical anticancer drug doxorubicin and anticancer phytochemicals derived from Tinospora extract. Cell viability measurements indicated that IC50 values varied in matrix stiffness dependent manner. Cells appeared to be less susceptible to these anticancer agents at lower stiffness compared to high stiffness matrices. Fluorescence microscopy observation at sub-cellular level indicated that drug-driven response on cytoskeleton organization is highly matrix stiffness dependent in nature. Further, the drug response on morphological parameters such as karyoplasmic ratio and cell-shape index was significantly affected by the matrix stiffness. ECM stiffness also governed the drug effect on cellular organelle architecture and functioning. We observed a strong correlation between ECM stiffness and the drug response to mitochondrial structure, potential and metabolic activity. Considering the direct relation of cell adhesion to substrate mechanosensing, we probed the matrix stiffness-dependent response of anticancer drugs on cell adhesion and deadhesion kinetics. Our analysis revealed that ECM stiffness significantly affected the effect of anticancer drugs on cell adhesion and deadhesion kinetics. Subsequent analysis on cellular mitogenic signaling indicated differential activation of MAPK signaling pathway via ECM stiffness-dependent manner. Taken together, these observations strongly suggested that cellular and subcellular responses of anticancer drugs are significantly governed by ECM stiffness in breast and lung cancer cells.

Citation Format: Atul Bharde, Snigdha Nadagauda, Megha Gaur, Vaishnavi Borade. Extracellular matrix stiffness regulates cellular response to anticancer drugs in breast and lung cancer cells [abstract]. In: Proceedings of the AACR Virtual Special Conference on the Evolving Tumor Microenvironment in Cancer Progression: Mechanisms and Emerging Therapeutic Opportunities; in association with the Tumor Microenvironment (TME) Working Group; 2021 Jan 11-12. Philadelphia (PA): AACR; Cancer Res 2021;81(5 Suppl):Abstract nr LT014.

Chemo-specific designs for the enumeration of circulating tumor cells: advances in liquid biopsy

Advanced materials and chemo-specific designs at the nano/micrometer-scale have ensured revolutionary progress in next-generation clinically relevant technologies. For example, isolating a rare population of cells, like circulating tumor cells (CTCs) from the blood amongst billions of other blood cells, is one of the most complex scientific challenges in cancer diagnostics. The chemical tunability for achieving this degree of exceptional specificity for extra-cellular biomarker interactions demands the utility of advanced entities and multistep reactions both in solution and in the insoluble state. Thus, this review delineates the chemo-specific substrates, chemical methods, and structure-activity relationships (SARs) of chemical platforms used for isolation and enumeration of CTCs in advancing the relevance of liquid biopsy in cancer diagnostics and disease management. We highlight the synthesis of cell-specific, tumor biomarker-based, chemo-specific substrates utilizing functionalized linkers through chemistry-based conjugation strategies. The capacity of these nano/micro substrates to enhance the cell interaction specificity and efficiency with the targeted tumor cells is detailed. Furthermore, this review accounts for the importance of CTC capture and other downstream processes involving genotypic and phenotypic CTC analysis in real-time for the detection of the early onset of metastases progression and chemotherapy treatment response, and for monitoring progression free-survival (PFS), disease-free survival (DFS), and eventually overall survival (OS) in cancer patients.

Abstract B30: Clinical correlation of circulating tumor cells as a blood marker in Indian head and neck cancer patients

Objectives: To establish a rapid, highly specific, efficient, sensitive, and affordable CTC enumeration liquid biopsy technology and to validate its efficacy to isolate CTC disseminating from epithelial tumors of HNC subpopulation in India. Furthermore, to study the correlation of CTC distribution from peripheral blood with respect to various clinicopathologic factors in these patients.

Materials and Methods: A cross-sectional study was conducted using peripheral blood from enrolled 350 HNC patients. CTC were isolated using DCGI, India-approved technology, that exploits EpCAM-based immunomagnetic separation. EpCAM+ tumor cells were isolated from only 1.5 mL blood and critically assayed for cytokeratin 18 (CK18) expression and quantified using fluorescence imaging of CTCs so as to obtain a threshold to further minimize nonspecific and false-positive enumeration. CTC enumeration was subsequently subjected to statistical correlation with various clinical and pathologic parameters.

Results: We detected CTCs from all HNC patients across its various subsites, and there was a minimum threshold of at least 12 CTC in early oral cancer patients according to their clinicopathologic signatures. Compared to early oral cancer patients, advanced nodal patients showed 40% escalation in CTC count, while up to 80% increase in CTC count was observed when associated with aggressive features such as lymphovascular emboli (LVE) and with extranodal extensions. Of note, laryngopharyngeal primary had the highest mean CTC count of 33 in 1.5mL blood. Conversely, patients with advanced disease had higher CTC count and this was staggered in comparison with nearly but not all of the clinical features. Remarkably, higher clinical N (nodal) stage statistically correlated with increased CTC count and a marked increase in CTC was seen in tumors that showed lymphovascular emboli on histopathology and extranodal extension. The CTC counts were independent of parameters such as the age, sex, T stage, perineural invasion, bone involvement, or skin involvement. There was a notable trend towards reduced CTC count after chemotherapy; however, it was not statistically significant.

Conclusion: Our rapid and efficient CTC platform has demonstrated and clinically validated its use in Indian HNC phenotypes. This is the first comprehensive study to show a staggering positive correlation of CTC with various clinicopathologic factors. It comprised the largest number of oral cancer patients throughout the entire spectrum of HNSCC, the most common cancer in India. High CTC counts among HNC patients could possibly be one of the reasons for their dismal outcomes, and further studies with a correlation of CTC with patient survival in HNC are warranted. However, this study strongly implicates a perspective utility of CTC as a tumor marker in establishing the clinical staging in HNC patients.

Citation Format: Jayant Khandare, Burhanuddin Nuruddin Qayyumi, Atul Bharde, Gourishankar Aland, Ajit Sagare, Swati Tripathi, Nitin Singh, Sreeja Jayant, Ashish Muglikar, Reecha Badave, Aravindan Vasudevan, Kumar Prabhash, Pankaj Chaturvedi. Clinical correlation of circulating tumor cells as a blood marker in Indian head and neck cancer patients [abstract]. In: Proceedings of the AACR Special Conference on Advances in Liquid Biopsies; Jan 13-16, 2020; Miami, FL. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(11_Suppl):Abstract nr B30.

Correlation of CTCs with disease progression in Indian oral cancer patients

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Background: Head and neck squamous cell carcinoma is leading cancer in the India with Oral squamous cell carcinoma (OSCC) as the most frequent subtype. OSCC is classified as a locoregional disease and its increased frequency is attributed to lack of good biomarkers compared to other epithelial cancers. At the time of diagnosis, above 50% of cases present the manifestation of advanced-stage disease, and are predisposed to disease failure in spite of appropriate treatment. Thus, early diagnosis of OSCC can significantly reduce the disease burden. Here we describe regulatory approved method to establish Circulating tumor cells (CTCs) presence in OSCC Indian patients and its positive correlation with various clinicopathological parameters, suggesting the potential use of CTCs as a significant parameter to stratify oral cancer with respect to the disease advancement. Methods: In a cross-sectional observational study, 230 OSCC patients at the different pathological stage of the disease and treatment mode were enrolled. CTCs were isolated using approved OncoDiscover liquid biopsy technology (Drug controller general of India approved), platform technology based on immunomagnetic CTC enumeration. CTCs were detected for CK18 presence and well-defined, DAPI-stained nuclei. Enumerated CTC subsequently analyzed for various clinic-pathological parameters such as pstage, extra-capsular spread (ECS), lymphovascular emboli (LVE), perineural invasion (PNI) and depth of invasion (DOI). CTC cut off values were obtained to differentiate early vs advanced stages with respect to different clinical stages and parameters. Results: CTCs of OSCC patients correlated positively with the cancer stages (clinical as well as pathological) as well as aggressive pathological features. The presence of aggressive pathological features that often suggest the poor outcome of the disease, we observed a 25-50 % increase in CTC number. Early stage, treatment naïve patients had lower number of CTCs. Mean CTC number in advanced-stage patients was 50 % higher than early-stage OSCC patients. Conclusions: Considering a positive correlation of CTC number with various pathophysiological features, CTC can be contemplated as a reliable parameter to predict the disease outcome in oral cancer. The consistent presence of CTC across all disease stages also suggests a probable nature of OSCC as a biological systematic disease. Clinical trial information: CTRI/2018/03/012905.

A highly efficient, low-cost, novel multicomponent nanosystem for rapid enumeration of circulating tumor cells

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Background: ‘Liquid biopsy’ technologies are unaffordable and unavailable in developing countries despite having highest cancer burden and mortality rates. Current Circulating Tumor Cell (CTCs) technologies sustain clinical concerns of a) non-specificity b) low efficiency c) high blood volume requirement d) long turn-around time, and d) exorbitant cost (~$900-1400). We report, an extremely low cost, innovative nanosystem for rapid enumeration of CTS with higher specificity and efficiency. Methods: We designed a nanosystem mediated by conjugation of anti-EpCAM through multi-reactive glutathione spacer, carbon allotrope and amine terminated dendrimer. The platform was evaluated for enhanced aqueous dispersibility and increased interaction with CTCs for rapid isolation and enumeration in 100 Head and Neck Cancer (HNC) patients having primary tumor sub-sites-oral cavity, larynx, hypopharynx, oropharynx, nasopharynx, salivary gland, and thyroid. The captured cells were immuno-stained and the optimal fluorescence acquisition intensity was validated in accounting CTCs with CK18 protein expression. There was complete elimination of the false positive normal cells (NC) count to CTCs by our method. The analysis was performed with only 1.5 ml of collected blood samples. Results: The CTC distribution in cohort study ranged from 1 - 85 cells per 1.5 mL of blood. In more than 80% of patient’s CTCs, the quantitative estimation of anti-CK18 protein over-expression indicated ~10-fold higher intensity over to NCs. As compared to treatment naive, recurrent, and disease-free patients, the spread of CTC number across the clinical range appeared to be tight (close to mean value). The CTC enumeration sensitivity linearity was ~99.2%, and the complete enumeration process time was under 03 hours/1.5 ml of blood. Consequently, efficient, rapid and yet affordable CTC platform was designed and clinically validated. Conclusions: ‘OncoDiscover’ liquid biopsy technology for CTC enumeration is poised to revolutionize the liquid biopsy due to its high sensitivity and affordability (~ $120) and shall resolve a major unmet medical need in impoverished world.

Self-propelled carbon nanotube based microrockets for rapid capture and isolation of circulating tumor cells

Here, we report a non-invasive strategy for isolating cancer cells by autonomously propelled carbon nanotube (CNT) microrockets. H2O2-driven oxygen (O2) bubble-propelled microrockets were synthesized using CNT and Fe3O4 nanoparticles in the inner surface and covalently conjugating transferrin on the outer surface. Results show that self-propellant microrockets can specifically capture cancer cells.

On-chip magnetic separation and encapsulation of cells in droplets

Single cell study is gaining importance because of the cell-to-cell variation that exists within cell population, even after significant initial sorting. Analysis of such variation at the gene expression level could impact single cell functional genomics, cancer, stem-cell research, and drug screening. The on-chip monitoring of individual cells in an isolated environment would prevent cross-contamination, provide high recovery yield, and enable study of biological traits at a single cell level. These advantages of on-chip biological experiments is a significant improvement for a myriad of cell analyses methods, compared to conventional methods, which require bulk samples and provide only averaged information on cell structure and function. We report on a device that integrates a mobile magnetic trap array with microfluidic technology to provide the possibility of separation of immunomagnetically labeled cells and their encapsulation with reagents into picoliter droplets for single cell analysis. The simultaneous reagent delivery and compartmentalization of the cells immediately following sorting are all performed seamlessly within the same chip. These steps offer unique advantages such as the ability to capture cell traits as originated from its native environment, reduced chance of contamination, minimal use of the reagents, and tunable encapsulation characteristics independent of the input flow. Preliminary assay on cell viability demonstrates the potential for the device to be integrated with other up- or downstream on-chip modules to become a powerful single-cell analysis tool.

Bacterial enzyme mediated biosynthesis of gold nanoparticles

Development of synthesis methods for anisotropic metal nanoparticles is of considerable interest due to their remarkable optoelectronic properties. Various shapes ranging from rods to cubes to tetrapods and prisms may be obtained by chemical methods. Here we show that anisotropic gold nanoparticles can be synthesized biologically by the bacterium Actinobacter spp. when challenged with gold chloride in the presence of Bovine serum albumin (BSA). We also observed that synthesis of gold nanoparticles occur with simultaneous induction of the protease enzyme secreted by the bacterium in the presence of BSA. The presence of BSA helps to enhance the rate of gold nanoparticles biosynthesis and may also impart some shape control. Controlling simple experimental conditions like incubation temperature and presence or absence of oxygen have drastic effect on the reaction rate and the morphology of the particles. Various assay experiments show that the presence of enzyme protease can act as a reducing as well as shape directing agent.

Extracellular biosynthesis of magnetite using fungi

The development of synthetic processes for oxide nanomaterials is an issue of considerable topical interest. While a number of chemical methods are available and are extensively used, the collaborations are often energy intensive and employ toxic chemicals. On the other hand, the synthesis of inorganic materials by biological systems is characterized by processes that occur at close to ambient temperatures and pressures, and at neutral pH (examples include magnetotactic bacteria, diatoms, and S-layer bacteria). Here we show that nanoparticulate magnetite may be produced at room temperature extracellularly by challenging the fungi, Fusarium oxysporum and Verticillium sp., with mixtures of ferric and ferrous salts. Extracellular hydrolysis of the anionic iron complexes by cationic proteins secreted by the fungi results in the room-temperature synthesis of crystalline magnetite particles that exhibit a signature of a ferrimagnetic transition with a negligible amount of spontaneous magnetization at low temperature.

Bacterial Aerobic Synthesis of Nanocrystalline Magnetite

The synthesis of iron oxide nanoparticles of the predominantly magnetite phase by the reaction of aqueous iron complexes with the bacterium, Actinobacter spp., is described. This reaction occurs at room temperature and under aerobic conditions, resulting in the formation of superparamagnetic magnetite.