Circulating tumor cells from 4D model have less integrin beta 4 expression

Revising the Role of Integrin Subunit β4 Expression in Colon Cancer Progression and Survival

PURPOSE

Integrin subunit β4 (β4) has been proposed to play an important role in colon cancer progression through its involvement in hemidesmosome disassembly processes and tumor cell migration. However, the association between β4 expression and clinicopathological outcomes in colon cancer remains unclear.

METHODS

Expression of β4 was assessed by immunohistochemistry in a large cohort of 651 colon cancer patients, the largest colon cancer cohort so far. Chi-squared tests were used to study the association between β4 expression and clinicopathological features. Overall and disease-free survival were assessed by Cox proportional hazard models.

RESULTS

Loss of β4 expression was associated with local tumor invasion. Only 17.9% of the pT1 tumors displayed weak β4 expression level versus 28.1% of pT4 tumors, and 25.0% of the pT1 tumors had a high expression level versus 8.6% of the pT4 tumors (p = 0.012). No association between β4 expression and overall (p = 0.845) or disease-free survival (p = 0.767) was encountered, which disputes the role of β4 as a biomarker of malignant behavior in colon cancer.

CONCLUSION

Contradictory reports have suggested opposite roles for β4 expression in (colon) cancer progression. In the present large cohort of colon cancer patients, we found that β4 expression was not associated with worse clinical prognosis, but decreased with advanced pathological tumor stage. Future studies should establish whether loss of β4 expression promotes invasive characteristics of colon cancer cells.

Transcriptional activators YAP/TAZ and AXL orchestrate dedifferentiation, cell fate, and metastasis in human osteosarcoma

Osteosarcoma (OS) is a molecularly heterogeneous, aggressive, poorly differentiated pediatric bone cancer that frequently spreads to the lung. Relatively little is known about phenotypic and epigenetic changes that promote lung metastases. To identify key drivers of metastasis, we studied human CCH-OS-D OS cells within a previously described rat acellular lung (ACL) model that preserves the native lung architecture, extracellular matrix, and capillary network. This system identified a subset of cells—termed derived circulating tumor cells (dCTCs)—that can migrate, intravasate, and spread within a bioreactor-perfused capillary network. Remarkably, dCTCs highly expressed epithelial-to-mesenchymal transition (EMT)-associated transcription factors (EMT-TFs), such as ZEB1, TWIST, and SOX9, which suggests that they undergo cellular reprogramming toward a less differentiated state by coopting the same epigenetic machinery used by carcinomas. Since YAP/TAZ and AXL tightly regulate the fate and plasticity of normal mesenchymal cells in response to microenvironmental cues, we explored whether these proteins contributed to OS metastatic potential using an isogenic pair of human OS cell lines that differ in AXL expression. We show that AXL inhibition significantly reduced the number of MG63.2 pulmonary metastases in murine models. Collectively, we present a laboratory-based method to detect and characterize a pure population of dCTCs, which provides a unique opportunity to study how OS cell fate and differentiation contributes to metastatic potential. Though the important step of clinical validation remains, our identification of AXL, ZEB1, and TWIST upregulation raises the tantalizing prospect that EMT-TF-directed therapies might expand the arsenal of therapies used to combat advanced-stage OS.

Circulating Tumour Cells in Predictive Molecular Pathology: Focus on Drug-Sensitive Assays and 3D Culture

Molecular cytopathology is a rapidly evolving field of cytopathology that provides biological information about the response to personalised therapy and about the prognosis of neoplasms diagnosed on cytological samples. Biomarkers such as circulating tumour cells and circulating tumour DNA are increasingly being evaluated in blood and in other body fluids. Such liquid biopsies are non-invasive, repeatable, and feasible also in patients with severe comorbidities. However, liquid biopsy may be challenging due to a low concentration of biomarkers. In such cases, biomarkers can be detected with highly sensitive molecular techniques, which in turn should be validated and integrated in a complex algorithm that includes tissue-based molecular assessments. The aim of this review is to provide the cytopathologist with practical information that is relevant to daily practice, particularly regarding the emerging role of circulating tumour cells in the field of predictive molecular pathology.

Small cell and non small cell lung cancer form metastasis on cellular 4D lung model

BACKGROUND

Metastasis is the main cause of death for lung cancer patients. The ex vivo 4D acellular lung model has been shown to mimic this metastatic process. However, the main concern is the model's lack of cellular components of the tumor's microenvironment. In this study, we aim to determine if the intact lung microenvironment will still allow lung cancer metastasis to form.

METHODS

We harvested a heart-lung block from a rat and placed it in a bioreactor after cannulating the pulmonary artery, trachea and tying the right main bronchus for 10-15 days without any tumor cells as a control group or with NSCLC (A549, H1299 or H460), SCLC (H69, H446 or SHP77) or breast cancer cell lines (MCF7 or MDAMB231) through the trachea. We performed lobectomy, H&E staining and IHC for human mitochondria to determine the primary tumor's growth and formation of metastatic lesions. In addition, we isolated circulating tumor cells (CTC) from the model seeded with GFP tagged cells.

RESULTS

In the control group, no gross tumor nodules were found, H&E staining showed hyperplastic cells and IHC showed no staining for human mitochondria. All of the models seeded with cancer cell lines formed gross primary tumor nodules that had microscopic characteristics of human cancer cells on H&E staining with IHC showing staining for human mitochondria. CTC were isolated for those cells labeled with GFP and they were viable in culture. Finally, all cell lines formed metastatic lesions with cells stained for human mitochondria.

CONCLUSION

The cellular ex vivo 4D model shows that human cancer cells can form a primary tumor, CTC and metastatic lesions in an intact cellular environment. This study suggests that the natural matrix scaffold is the only necessary component to drive metastatic progression and that cellular components play a role in modulating tumor progression.

Altered integrin expression patterns shown by microarray in human cutaneous melanoma

A large variety of molecular pathways in melanoma progression suggests that no individual molecular alteration is crucial in itself. Our aim was to define the molecular alterations underlying metastasis formation. Gene expression profiling was performed using microarray and qRT-PCR to define alterations between matched primary and metastatic melanoma cell lines. These data were integrated with publicly available unmatched tissue data. The invasiveness of cell lines was determined by Matrigel invasion assays and invasive clones from primary melanoma-derived cell lines were also selected. Two metastatic cell line models were created: the regional lymph node WM983A-WM983A-WM983B and the distant lung WM793B-WM793B-1205Lu metastatic models. The majority of metastasis genes were downregulated and enriched in adhesion and ITGA6-B4 pathways. Upregulation of immune pathways was characteristic of distant metastases, whereas increased Rap1 signaling was specific for regional (sub)cutaneous metastases. qRT-PCR analysis of selected integrins (A2, A3, A4, A9, B5, B8, A6, B1, and B3) highlighted the possible importance of ITGA3/4 and B8 in the metastatic process, distinguishing regional and distant metastases. We identified functionally relevant gene clusters that influenced metastasis formation. Our data provide further evidence that integrin expression patterns may be important in distant metastasis formation.

SR 11302, an AP-1 Inhibitor, Reduces Metastatic Lesion Formation in Ex Vivo 4D Lung Cancer Model

Activator protein (AP) -1 is a transcription factor, plays important role in cell differentiation, proliferation and apoptosis. Analysis of tumor cells grown on ex vivo 4D lung cancer model shows increase in components of AP-1, c-Fos and c-Jun in circulating tumor cells (CTC) compared to primary tumor. Our aim was to determine whether the AP-1 inhibitor SR11302 reduces metastatic lesion formation in the 4D model. Human lung cancer cell lines A549, H1299, and H460 were grown in the 4D model and treated with SR11302 (1 μM). We compared the number of cells in the metastatic site upon SR11302 treatment and number of viable CTCs isolated from the 4D model with parental cells treated/untreated with SR11302 on a petri dish. There were significantly fewer tumor cells per high-power field on metastatic site in 4D model seeded with H460 (p = 0.009), A549 (p = 0.01), or H1299 (p = 0.02) cells treated with SR11302. Furthermore, the CTCs from SR11302 treated 4D models, seeded with H460 (p = 0.04), A549 (p = 0.008), or H1299 (p = 0.01) cells had significantly fewer viable tumor cells after 4 days in culture than the respective untreated control. However, the SR11302 had no impact on the viability of parental H460 (p = 0.87), A549 (p = 0.93), or H1299 (p = 0.25) cells grown on a petri dish (2D). SR11302 reduces metastatic lesion formation in the ex vivo 4D lung cancer model due to the presence of an independent yet common pathway among three cell lines. The ex vivo 4D model may provide a tool to better understand the complex process of metastasis.

Amino acid transporter SLC38A3 promotes metastasis of non-small cell lung cancer cells by activating PDK1

BACKGROUND

Tumor metastasis is a finely-tuned pathological process coupled to metabolic reprogramming that includes both glutamine and glucose. The solute carrier SLC38A3, a member of amino acid/polyamine/organocation (APC) superfamily, is an l-glutamine transporter. It is not clear whether SLC38A3 involves the metastasis of NSCLC (non small cell lung cancer).

METHODS

The scratch test and transwell assay were used to determine the ability of NSCLC to migrate. Cellular amino acids content was determined by mass spectrometry. The cellular response to glutamine/histidine deficiency was evaluated in A549 cells. The expression of SLC38A3 was assayed in clinical NSCLC and paratumor tissues by histoimmunochemistry staining. A nude mouse model of NSCLC metastasis was developed by tail vein injection of tumor cells.

RESULTS

SLC38A3 was upregulated in metastatic NSCLC cells and its expression was correlated with prognosis of NSCLC patients. SLC38A3 overexpression promoted epithelial - mesenchymal transition (EMT) and migration of HCC827 and A549 human lung adenocarcinoma cells, and accelerated tumor metastasis in mice. We found that SLC38A3 decreased the cellular concentrations of glutamine and histidine, and the deficiency of glutamine or histidine activated PDK1/AKT signaling that in turn, triggered NSCLC metastasis.

CONCLUSIONS

SLC38A3 activated PDK1/AKT signaling and promoted metastasis of NSCLC through regulating glutamine and histidine transport, suggesting SLC38A3 as a potential therapeutic target for treatment of NSCLC.

Detection of Circulating Tumor Cells by Fluorescent Immunohistochemistry in Patients with Esophageal Squamous Cell Carcinoma: Potential Clinical Applications

BACKGROUND Circulating tumor cells (CTCs) are tumor cells that leave the primary tumor site and enter the bloodstream, where they can spread to other organs; they are very important in the diagnosis, treatment, and prognosis of malignant tumors. However, few studies have investigated CTCs in esophageal squamous cell carcinoma (ESCC). The aim of this study was to investigate the CTCs in blood of ESCC patients and its potential relevance to clinicopathological features and prognosis. MATERIAL AND METHODS CTCs were acquired by a negative enrichment method that used magnetic activated cell sorting (MACSTM). Fluorescent immunohistochemistry (IHC) was used to identify the CTCs. Then, the positive CTC patients with ESCC were analyzed, after which the relationship between CTCs and clinicopathologic features was evaluated. RESULTS In the present study, 62 out of 140 (44.3%) patients with ESCC were positive for CTCs. The positive rate of CTCs was significantly related with stage of ESCC patients (P=0.013). However, there was no relationship between CTC status and age, sex, smoking tumor history, tumor location, differentiation of tumor, lymphatic invasion, or lymph venous invasion (P>0.05). Kaplan-Meier analysis showed that patients positive for CTCs had significantly shorter survival time than patients negative for CTCs. Multivariate analysis demonstrated that stage and CTC status were significant prognostic factors for patients with ESCC. CONCLUSIONS CTCs positivity is an independent prognostic biomarker that indicates a worse prognosis for patients with ESCC.

Human Lung Fibroblasts Inhibit Non-Small Cell Lung Cancer Metastasis in Ex Vivo 4D Model

BACKGROUND

We determined the effect of human lung fibroblasts (LFs) in metastatic lesion formation in a four-dimensional (4D) lung cancer model.

METHODS

Human cancer-associated fibroblasts (CAFs) were isolated from the primary tumor, and normal LFs were isolated from adjacent lung using fluorescence-activated cell sorting. The 4D metastatic lung cancer model was seeded with the human lung cancer cell lines (H460, A549, and H1299) alone or was seeded with CAFs or LFs. In addition, the 4D model seeded with human lung cancer cell lines was also treated with conditioned media of LFs or CAFs grown on the 4D model. We determined the number of metastatic tumor cells per high-power field on the model.

RESULTS

There were significantly fewer metastatic lesions per high-power field in the 4D model seeded with the H460 cell line and LFs compared with H460 alone on day 15 (p = 0.008) or compared with H460 and CAFs (p = 0.002). This relationship was also seen with A549 and H1299 tumor cells. Moreover, the H460 cell line treated with conditioned media from the 4D model seeded with LFs had significantly fewer metastatic lesions than the 4D model seeded with CAFs. This was also seen with two other pairs of human fibroblasts obtained from patients.

CONCLUSIONS

The secreted factor from LFs grown on the 4D model inhibits the formation of metastatic lesions. The 4D model may be used to determine the role of different components of the tumor's microenvironment in metastatic lesion formation, and this secreted factor may provide a novel therapy for treatment of cancer metastasis.