Human Tumor-Derived Matrix Improves the Predictability of Head and Neck Cancer Drug Testing

A bioengineered tumor matrix-based scaffold for the evaluation of melatonin efficacy on head and neck squamous cancer stem cells

Head and neck squamous cell carcinoma (HNSCC) presents a significant challenge worldwide due to its aggressiveness and high recurrence rates post-treatment, often linked to cancer stem cells (CSCs). Melatonin shows promise as a potent tumor suppressor; however, the effects of melatonin on CSCs remain unclear, and the development of models that closely resemble tumor heterogeneity could help to better understand the effects of this molecule. This study developed a tumor scaffold based on patient fibroblast-derived decellularized extracellular matrix that mimics the HNSCC microenvironment. Our study investigates the antitumoral effects of melatonin within this context. We validated its strong antiproliferative effect on HNSCC CSCs and the reduction of tumor invasion and migration markers, even in a strongly chemoprotective environment, as it is required to increase the minimum doses necessary to impact tumor viability compared to the non-scaffolded tumorspheres culture. Moreover, melatonin exhibited no cytotoxic effects on healthy cells co-cultured in the tumor hydrogel. This scaffold-based platform allows an in vitro study closer to HNSCC tumor reality, including CSCs, stromal component, and a biomimetic matrix, providing a new valuable research tool in precision oncology.

Engineering models of head and neck and oral cancers on-a-chip

Head and neck cancers (HNCs) rank as the sixth most common cancer globally and result in over 450 000 deaths annually. Despite considerable advancements in diagnostics and treatment, the 5-year survival rate for most types of HNCs remains below 50%. Poor prognoses are often attributed to tumor heterogeneity, drug resistance, and immunosuppression. These characteristics are difficult to replicate using in vitro or in vivo models, culminating in few effective approaches for early detection and therapeutic drug development. Organs-on-a-chip offer a promising avenue for studying HNCs, serving as microphysiological models that closely recapitulate the complexities of biological tissues within highly controllable microfluidic platforms. Such systems have gained interest as advanced experimental tools to investigate human pathophysiology and assess therapeutic efficacy, providing a deeper understanding of cancer pathophysiology. This review outlines current challenges and opportunities in replicating HNCs within microphysiological systems, focusing on mimicking the soft, glandular, and hard tissues of the head and neck. We further delve into the major applications of organ-on-a-chip models for HNCs, including fundamental research, drug discovery, translational approaches, and personalized medicine. This review emphasizes the integration of organs-on-a-chip into the repertoire of biological model systems available to researchers. This integration enables the exploration of unique aspects of HNCs, thereby accelerating discoveries with the potential to improve outcomes for HNC patients.

Stroma modulation of radiation response in head and neck squamous cell carcinoma: Insights from zebrafish larvae xenografts

BACKGROUND

The tumour microenvironment (TME) of head and neck squamous cell carcinoma (HNSCC) consists of different subtypes of cells that interact with the tumour or with each other. This study investigates the possibility of co-culturing HNSCC cells with different stroma cells in a zebrafish xenograft model, focusing on the effect of stroma cells on HNSCC growth and response to irradiation.

MATERIAL AND METHOD

HNSCC metastatic cell line HSC-3 was used along with five types of stroma cells: normal gingival fibroblasts (NOF), cancer associated fibroblasts (CAF), macrophages, CD4+ T cells, and human umbilical vein endothelial cells (HUVEC). The mixture of HSC-3 cells and each-stroma cell type-was injected into 2-day post-fertilization zebrafish embryos, and the effect of stroma cells on tumour growth was tested. The study also aimed to mimic the HNSCC tumour by injecting a mixture of HSC-3 cells, CAFs, macrophages, and HUVECs into zebrafish embryos and testing the effect of these stroma cells on the cancer cells' response to irradiation compared to HSC-3-only tumours.

RESULTS

CAFs had a significant inducement effect on tumour size, while HUVECs showed the opposite effect. The irradiated group of HSC-3-only tumour had a significantly smaller tumor cell area compared to the control, while the group with stroma cells and HSC-3 cells showed cancer cells being resistant to irradiation.

CONCLUSION

This is the first report of co-culturing cancer cells with several types of stroma cells using a zebrafish xenograft model. This study also highlighted the role of stroma cells in turning the cancer cells from radioresponsive to radioresistant.

In Vitro Models of Head and Neck Cancer: From Primitive to Most Advanced

For several decades now, researchers have been trying to answer the demand of clinical oncologists to create an ideal preclinical model of head and neck squamous cell carcinoma (HNSCC) that is accessible, reproducible, and relevant. Over the past years, the development of cellular technologies has naturally allowed us to move from primitive short-lived primary 2D cell cultures to complex patient-derived 3D models that reproduce the cellular composition, architecture, mutational, or viral load of native tumor tissue. Depending on the tasks and capabilities, a scientific laboratory can choose from several types of models: primary cell cultures, immortalized cell lines, spheroids or heterospheroids, tissue engineering models, bioprinted models, organoids, tumor explants, and histocultures. HNSCC in vitro models make it possible to screen agents with potential antitumor activity, study the contribution of the tumor microenvironment to its progression and metastasis, determine the prognostic significance of individual biomarkers (including using genetic engineering methods), study the effect of viral infection on the pathogenesis of the disease, and adjust treatment tactics for a specific patient or groups of patients. Promising experimental results have created a scientific basis for the registration of several clinical studies using HNSCC in vitro models.

The Three-Dimensional In Vitro Cell Culture Models in the Study of Oral Cancer Immune Microenvironment

The onset and progression of oral cancer are accompanied by a dynamic interaction with the host immune system, and the immune cells within the tumor microenvironment play a pivotal role in the development of the tumor. By exploring the cellular immunity of oral cancer, we can gain insight into the contribution of both tumor cells and immune cells to tumorigenesis. This understanding is crucial for developing effective immunotherapeutic strategies to combat oral cancer. Studies of cancer immunology present unique challenges in terms of modeling due to the extraordinary complexity of the immune system. With its multitude of cellular components, each with distinct subtypes and various activation states, the immune system interacts with cancer cells and other components of the tumor, ultimately shaping the course of the disease. Conventional two-dimensional (2D) culture methods fall short of capturing these intricate cellular interactions. Mouse models enable us to learn about tumor biology in complicated and dynamic physiological systems but have limitations as the murine immune system differs significantly from that of humans. In light of these challenges, three-dimensional (3D) culture systems offer an alternative approach to studying cancer immunology and filling the existing gaps in available models. These 3D culture models provide a means to investigate complex cellular interactions that are difficult to replicate in 2D cultures. The direct study of the interaction between immune cells and cancer cells of human origin offers a more relevant and representative platform compared to mouse models, enabling advancements in our understanding of cancer immunology. This review explores commonly used 3D culture models and highlights their significant contributions to expanding our knowledge of cancer immunology. By harnessing the power of 3D culture systems, we can unlock new insights that pave the way for improved strategies in the battle against oral cancer.

Novel human lymph node-derived matrix supports the adhesion of metastatic oral carcinoma cells

BACKGROUND

3D culture is increasingly used in cancer research, as it allows the growth of cells in an environment that mimics in vivo conditions. Metastases are the primary cause of morbidity and mortality in cancer patients, and solid tumour metastases are mostly located in lymph nodes. Currently, there are no techniques that model the pre-metastatic lymph node microenvironment in vitro. In this study, we prepared a novel extracellular matrix, Lymphogel, which is derived from lymph nodes, mimicking the tumour microenvironment (TME) of metastatic carcinoma cells. We tested the suitability of the new matrix in various functional experiments and compared the results with those obtained using existing matrices.

METHODS

We used both commercial and patient-derived primary and metastatic oral tongue squamous cell carcinoma (OTSCC) cell lines. We characterized the functional differences of these cells using three different matrices (human uterine leiomyoma-derived Myogel, human pre-metastatic neck lymph node-derived Lymphogel (h-LG), porcine normal neck lymph node-derived Lymphogel (p-LG) in proliferation, adhesion, migration and invasion assays. We also performed proteomic analyses to compare the different matrices in relation to their functional properties.

RESULTS

OTSCC cells exhibited different adhesion and invasion patterns depending on the matrix. Metastatic cell lines showed improved ability to adhere to h-LG, but the effects of the matrices on cell invasion fluctuated non-significantly between the cell lines. Proteomic analyses showed that the protein composition between matrices was highly variable; Myogel contained 618, p-LG 1823 and h-LG 1520 different proteins. The comparison of all three matrices revealed only 120 common proteins. Analysis of cellular pathways and processes associated with proteomes of each matrix revealed similarities of Myogel with h-LG but less with p-LG. Similarly, p-LG contained the least adhesion-related proteins compared with Myogel and h-LG. The highest number of unique adhesion-related proteins was present in h-LG.

CONCLUSIONS

We demonstrated that human pre-metastatic neck lymph node-derived matrix is suitable for studying metastatic OTSCC cells. As a whole-protein extract, h-LG provides new opportunities for in vitro carcinoma cell culture experiments.

Mapping the Potential of Microfluidics in Early Diagnosis and Personalized Treatment of Head and Neck Cancers

Head and neck cancers (HNCs) account for ~4% of all cancers in North America and encompass cancers affecting the oral cavity, pharynx, larynx, sinuses, nasal cavity, and salivary glands. The anatomical complexity of the head and neck region, characterized by highly perfused and innervated structures, presents challenges in the early diagnosis and treatment of these cancers. The utilization of sub-microliter volumes and the unique phenomenon associated with microscale fluid dynamics have facilitated the development of microfluidic platforms for studying complex biological systems. The advent of on-chip microfluidics has significantly impacted the diagnosis and treatment strategies of HNC. Sensor-based microfluidics and point-of-care devices have improved the detection and monitoring of cancer biomarkers using biological specimens like saliva, urine, blood, and serum. Additionally, tumor-on-a-chip platforms have allowed the creation of patient-specific cancer models on a chip, enabling the development of personalized treatments through high-throughput screening of drugs. In this review, we first focus on how microfluidics enable the development of an enhanced, functional drug screening process for targeted treatment in HNCs. We then discuss current advances in microfluidic platforms for biomarker sensing and early detection, followed by on-chip modeling of HNC to evaluate treatment response. Finally, we address the practical challenges that hinder the clinical translation of these microfluidic advances.

The effect of matrices on the gene expression profile of patient-derived head and neck carcinoma cells for in vitro therapy testing

OBJECTIVE

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive tumor with a 5-year mortality rate of ~ 50%. New in vitro methods are needed for testing patients' cancer cell response to anti-cancer treatments. We aimed to investigate how the gene expression of fresh carcinoma tissue samples and freshly digested single cancer cells change after short-term cell culturing on plastic, Matrigel or Myogel. Additionally, we studied the effect of these changes on the cancer cells' response to anti-cancer treatments.

MATERIALS/METHODS

Fresh tissue samples from HNSCC patients were obtained perioperatively and single cells were enzymatically isolated and cultured on either plastic, Matrigel or Myogel. We treated the cultured cells with cisplatin, cetuximab, and irradiation; and performed cell viability measurement. RNA was isolated from fresh tissue samples, freshly isolated single cells and cultured cells, and RNA sequencing transcriptome profiling and gene set enrichment analysis were performed.

RESULTS

Cancer cells obtained from fresh tissue samples changed their gene expression regardless of the culturing conditions, which may be due to the enzymatic digestion of the tissue. Myogel was more effective than Matrigel at supporting the upregulation of pathways related to cancer cell proliferation and invasion. The impacts of anti-cancer treatments varied between culturing conditions.

CONCLUSIONS

Our study showed the challenge of in vitro cancer drug testing using enzymatic cell digestion. The upregulation of many targeted pathways in the cultured cells may partially explain the common clinical failure of the targeted cancer drugs that pass the in vitro testing.

Identity matters: cancer stem cells and tumour plasticity in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) represents frequent yet aggressive tumours that encompass complex ecosystems of stromal and neoplastic components including a dynamic population of cancer stem cells (CSCs). Recently, research in the field of CSCs has gained increased momentum owing in part to their role in tumourigenicity, metastasis, therapy resistance and relapse. We provide herein a comprehensive assessment of the latest progress in comprehending CSC plasticity, including newly discovered influencing factors and their possible application in HNSCC. We further discuss the dynamic interplay of CSCs within tumour microenvironment considering our evolving appreciation of the contribution of oral microbiota and the pressing need for relevant models depicting their features. In sum, CSCs and tumour plasticity represent an exciting and expanding battleground with great implications for cancer therapy that are only beginning to be appreciated in head and neck oncology.

Amphipathic barbiturates as marine product mimics with cytolytic and immunogenic effects on head and neck squamous cell carcinoma cell lines

The incidence of head and neck squamous cell carcinoma (HNSCC) is increasing and the conventional treatments for this form of cancer can be tough. Despite the success of existing immunotherapies in some HNSCC patients, many do not respond to this type of treatment. Thus, the development of novel anti-cancer therapies should be prioritized. In the current study, the anticancer activity of a panel of novel compounds, herein termed marine product mimics (MPMs), against HNSCC cell lines is explored. The previously reported compound MPM-1, which is structurally related to the novel MPMs, was shown to have promising effects on the HNSCC cell line HSC-3. The results from the current study indicate that the novel MPMs are more potent than MPM-1 but cause a similar type of cell death. The results indicated that the MPMs must cross through the cell membrane to exert their action and that they are lysosomotropic. Further experiments showed that some of the MPMs could induce phosphorylation of eukaryotic initiation factor 2α (eIF2α) in HSC-3 and UT-SCC-24A cells, which indicates that they can activate the integrated stress response that is strongly associated with immunogenic cell death. Cell surface expression of calreticulin and release of HMGB1 and ATP, which are all hallmarks of immunogenic cell death, was also demonstrated in HSC-3 and UT-SCC-24A cells treated with MPMs. This suggests that the MPMs are interesting candidates for future HNSCC cancer therapies.

Evaluation of AMG510 Therapy on KRAS-Mutant Non-Small Cell Lung Cancer and Colorectal Cancer Cell Using a 3D Invasive Tumor Spheroid System under Normoxia and Hypoxia

A 3D tumor spheroid has been increasingly applied in pharmaceutical development for its simulation of the tumor structure and microenvironment. The embedded-culture of a tumor spheroid within a hydrogel microenvironment could help to improve the mimicking of in vivo cell growth and the development of 3D models for tumor invasiveness evaluation, which could enhance its drug efficiency prediction together with cell viability detection. NCI-H23 spheroids and CT-26 spheroids, from a non-small cell lung cancer and colorectal cancer cell line, respectively, together with extracellular matrix were generated for evaluating their sensitivity to AMG510 (a KRAS^G12C inhibitor) under normoxia and hypoxia conditions, which were created by an on-stage environmental chamber. Results demonstrated that NCI-H23, the KRAS^G12C moderate expression cell line, only mildly responded to AMG510 treatment in normal 2D and 3D cultures and could be clearly evaluated by our system in hypoxia conditions, while the negative control CT-26 (G12D-mutant) spheroid exhibited no significant response to AMG510 treatment. In summary, our system, together with a controlled microenvironment and imaging methodology, provided an easily assessable and effective methodology for 3D in vitro drug efficiency testing and screenings.

Targeting PI3K/AKT/mTOR Signaling Pathway as a Radiosensitization in Head and Neck Squamous Cell Carcinomas

Globally, there are over half a million new patients with head and neck squamous cell carcinomas (HNSCC) every year. The current therapeutic approaches to HNSCC are surgery and adjuvant radiotherapy. These approaches carry a high incidence of metastasis or recurrence from HNSCC cells' radioresistance. Recent studies have revealed that a combination with radiosensitizers can be used to improve the radioresistance in HNSCC; however, few agents are approved as radiosensitizers. The constitutive activation of phosphatidylinositol-3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is a vitally oncogenic type of signaling that promotes tumorigenesis, metastasis, and radiotherapy resistance in HNSCC. Pharmacological targeting of PI3K/AKT/mTOR signaling pathway is considered a promising strategy of radiosensitization in HNSCC. In this review, we summarize the oncogenic significance of PI3K/AKT/mTOR signaling in HNSCC with radiotherapy resistance and highlight the therapeutic potential of small molecule inhibitors against PI3K/AKT/mTOR signaling for the radiosensitization in HNSCC treatment. It provides a mechanistic framework for the development of new drugs for radiosensitization in HNSCC radiotherapy via targeting PI3K/AKT/mTOR signaling pathway.

In vitro models as tools for screening treatment options of head and neck cancer

Various in vitro models using primary and established 2- and 3-dimensional cultures, multicellular tumor spheroids, standardized tumor slice cultures, tumor organoids, and microfluidic systems obtained from tumor lesions/biopsies of head and neck cancer (HNC) have been employed for exploring and monitoring treatment options. All of these in vitro models are to a different degree able to capture the diversity of tumors, recapitulate the disease genetically, histologically, and functionally and retain their tumorigenic potential upon xenotransplantation. The models were used for the characterization of the malignant features of the tumors and for in vitro screens of drugs approved for the treatment of HNC, including chemotherapy and radiotherapy as well as recently developed targeted therapies and immunotherapies, or for novel treatments not yet licensed for these tumor entities. The implementation of the best suitable model will enlarge our knowledge of the oncogenic properties of HNC, expand the drug repertoire and help to develop individually tailored treatment strategies resulting in the translation of these findings into the clinic. This review summarizes the different approaches using preclinical in vitro systems with their advantages and disadvantages and their implementation as preclinical platforms to predict disease course, evaluate biomarkers and test therapy efficacy.

In vitro models for head and neck cancer: Current status and future perspective

The 5-year overall survival rate remains approximately 50% for head and neck (H&N) cancer patients, even though new cancer drugs have been approved for clinical use since 2016. Cancer drug studies are now moving toward the use of three-dimensional culture models for better emulating the unique tumor microenvironment (TME) and better predicting in vivo response to cancer treatments. Distinctive TME features, such as tumor geometry, heterogenous cellularity, and hypoxic cues, notably affect tissue aggressiveness and drug resistance. However, these features have not been fully incorporated into in vitro H&N cancer models. This review paper aims to provide a scholarly assessment of the designs, contributions, and limitations of in vitro models in H&N cancer drug research. We first review the TME features of H&N cancer that are most relevant to in vitro drug evaluation. We then evaluate a selection of advanced culture models, namely, spheroids, organotypic models, and microfluidic chips, in their applications for H&N cancer drug research. Lastly, we propose future opportunities of in vitro H&N cancer research in the prospects of high-throughput drug screening and patient-specific drug evaluation.

Ex Vivo Drug Screening Informed Targeted Therapy for Metastatic Parotid Squamous Cell Carcinoma

The purpose of ex vivo drug screening in the context of precision oncology is to serve as a functional diagnostic method for therapy efficacy modeling directly on patient-derived tumor cells. Here, we report a case study using integrated multiomics ex vivo drug screening approach to assess therapy efficacy in a rare metastatic squamous cell carcinoma of the parotid gland. Tumor cells isolated from lymph node metastasis and distal subcutaneous metastasis were used for imaging-based single-cell resolution drug screening and reverse-phase protein array-based drug screening assays to inform the treatment strategy after standard therapeutic options had been exhausted. The drug targets discovered on the basis of the ex vivo measured drug efficacy were validated with histopathology, genomic profiling, and in vitro cell biology methods, and targeted treatments with durable clinical responses were achieved. These results demonstrate the use of serial ex vivo drug screening to inform adjuvant therapy options prior to and during treatment and highlight HER2 as a potential therapy target also in metastatic squamous cell carcinoma of the salivary glands.

Comparative Analysis of Vascular Mimicry in Head and Neck Squamous Cell Carcinoma: In Vitro and In Vivo Approaches

Tissue vasculature provides the main conduit for metastasis in solid tumours including head and neck squamous cell carcinoma (HNSCC). Vascular mimicry (VM) is an endothelial cell (EC)-independent neovascularization pattern, whereby tumour cells generate a perfusable vessel-like meshwork. Yet, despite its promising clinical utility, there are limited approaches to better identify VM in HNSCC and what factors may influence such a phenomenon in vitro. Therefore, we employed different staining procedures to assess their utility in identifying VM in tumour sections, wherein mosaic vessels may also be adopted to further assess the VM-competent cell phenotype. Using 13 primary and metastatic HNSCC cell lines in addition to murine- and human-derived matrices, we elucidated the impact of the extracellular matrix, tumour cell type, and density on the formation and morphology of cell-derived tubulogenesis in HNSCC. We then delineated the optimal cell numbers needed to obtain a VM meshwork in vitro, which revealed cell-specific variations and yet consistent expression of the EC marker CD31. Finally, we proposed the zebrafish larvae as a simple and cost-effective model to evaluate VM development in vivo. Taken together, our findings offer a valuable resource for designing future studies that may facilitate the therapeutic exploitation of VM in HNSCC and other tumours.

Effects of Fermented Wheat Germ Extract on Oral Cancer Cells: An In Vitro Study

Oral carcinoma is one of the most aggressive cancers, and despite the advances in the therapy, its mortality is still high. An attention in cancer treatment has focused on natural compounds due to their potential beneficial effects on human health. In this study, the effects of dietary supplement Fermented Wheat Germ Extract (FWGE) on oral tongue squamous cell carcinoma (OTSCC) cells were investigated In Vitro using three cell lines (HSC-3, SAS, SCC-25) with variable aggressiveness. The cell viability was significantly decreased by the treatment with high concentration of FWGE in every cell line. Regarding migration and invasion, HSC-3 and SCC-25 cells were most sensitive to FWGE since their movement was significantly reduced with 5 and 10 mg/ml FWGE, while SAS was inhibited only with 10 mg/ml FWGE. Chemotherapeutic compounds (cisplatin and 5-fluorouracil) significantly reduced all OTSCC cells viability. Importantly, combination of these drugs with 10 mg/ml FWGE significantly decreased the cell viability compared to the treatment with the chemotherapeutics or FWGE alone. Based on these In Vitro experiments, the use of FWGE seems to improve the anticancer effects on OTSCC cells. Further In Vivo and clinical studies should be conducted to verify the positive effects of FWGE for OTSCC patients.

The effect of fascin 1 inhibition on head and neck squamous cell carcinoma cells

Fascin 1 plays important pro-metastatic roles in head and neck carcinoma (HNSCC) migration, invasion, and metastasis. However, limited advancement in targeting metastasis remains a major obstacle in improving HNSCC patients' survival. Therefore, we assessed the therapeutic potential of fascin 1 targeted inhibition and its potential prognostic value in HNSCC patients. Using in vitro and in vivo approaches, we investigated the effect of compound G2, a novel fascin 1 inhibitor, on HNSCC cells migration, invasion, and metastasis. High-throughput screening (HTS) was used to assess cytotoxic activity of compound G2 alone or combined with irradiation. We also evaluated the prognostic potential of fascin 1 in HNSCC patients. Interestingly, compound G2 reduced carcinoma cells migration and invasion in vitro and inhibited metastasis in vivo. Moreover, HTS revealed a modest cytotoxic activity of the compound G2 on HNSCC cell lines. Irradiation did not synergistically enhance the compound G2-mediated cytotoxic activity. Survival analyses showed that high fascin 1 immunoexpression, at the tumor invasive front, was associated with cancer-specific mortality in the advanced stages of HNSCC. Collectively, our findings suggest that fascin 1 represents a promising anti-metastatic therapeutic target and a useful prognostic marker in patients with HNSCC. Novel anti-metastatic agents could provide a valuable addition to cancer therapy.

High-throughput compound screening identifies navitoclax combined with irradiation as a candidate therapy for HPV-negative head and neck squamous cell carcinoma

Conventional chemotherapeutic agents are nonselective, often resulting in severe side effects and the development of resistance. Therefore, new molecular-targeted therapies are urgently needed to be integrated into existing treatment regimens. Here, we performed a high-throughput compound screen to identify a synergistic interaction between ionizing radiation and 396 anticancer compounds. The assay was run using five human papillomavirus (HPV)-negative head and neck squamous cell carcinoma (HNSCC) cell lines cultured on the human tumor-derived matrix Myogel. Our screen identified several compounds with strong synergistic and antagonistic effects, which we further investigated using multiple irradiation doses. Navitoclax, which emerged as the most promising radiosensitizer, exhibited synergy with irradiation regardless of the p53 mutation status in all 13 HNSCC cell lines. We performed a live cell apoptosis assay for two representative HNSCC cell lines to examine the effects of navitoclax and irradiation. As a single agent, navitoclax reduced proliferation and induced apoptosis in a dose-dependent manner, whereas the navitoclax-irradiation combination arrested cell cycle progression and resulted in substantially elevated apoptosis. Overall, we demonstrated that combining navitoclax with irradiation resulted in synergistic in vitro antitumor effects in HNSCC cell lines, possibly indicating the therapeutic potential for HNSCC patients.

The critical effects of matrices on cultured carcinoma cells: Human tumor-derived matrix promotes cell invasive properties

The interaction between squamous cell carcinoma (SCC) cells and the tumor microenvironment (TME) plays a major role in cancer progression. Therefore, understanding the TME is essential for the development of cancer therapies. We used four (primary and metastatic) head and neck (HN) SCC cell lines and cultured them on top of or within 5 matrices (mouse sarcoma-derived Matrigel®, rat collagen, human leiomyoma-derived Myogel, human fibronectin and human fibrin). We performed several assays to study the effects of these matrices on the HNSCC behavior, such as proliferation, migration, and invasion, as well as cell morphology, and molecular gene profile. Carcinoma cells exhibited different growth patterns depending on the matrix. While fibrin enhanced the proliferation of all the cell lines, collagen did not. The effects of the matrices on cancer cell migration were cell line dependent. Carcinoma cells in Myogel-collagen invaded faster in scratch wound invasion assay. On the other hand, in the spheroid invasion assay, three out of four cell lines invaded faster in Myogel-fibrin. These matrices significantly affected hundreds of genes and a number of pathways, but the effects were cell line dependent. The matrix type played a major role in HNSCC cell phenotype. The effects of the ECMs were either constant, or cell line dependent. Based on these results, we suggest to select the most suitable matrix, which provides the closest condition to the in vivo TME, in order to get reliable results in in vitro experiments.