Mutual paracrine effects of oral squamous cell carcinoma cells and normal oral fibroblasts: induction of fibroblast to myofibroblast transdifferentiation and modulation of tumor cell proliferation

Crosstalk between CAFs and tumour cells in head and neck cancer

Head and neck squamous cell carcinomas (HNSCCs) are amongst the most aggressive, complex, and heterogeneous malignancies. The standard of care treatments for HNC patients include surgery, radiotherapy, chemotherapy, or their combination. However, around 50% do not benefit while suffering severe toxic side effects, costing the individuals and society. Decades have been spent to improve HNSCC treatment outcomes with only limited success. Much of the research in HNSCC treatment has focused on understanding the genetics of the HNSCC malignant cells, but it has become clear that tumour microenvironment (TME) plays an important role in the progression as well as treatment response in HNSCC. Understanding the crosstalk between cancer cells and TME is crucial for inhibiting progression and treatment resistance. Cancer-associated fibroblasts (CAFs), the predominant component of stroma in HNSCC, serve as the primary source of extra-cellular matrix (ECM) and various pro-tumoral composites in TME. The activation of CAFs in HNSCC is primarily driven by cancer cell-secreted molecules, which in turn induce phenotypic changes, elevated secretive status, and altered ECM production profile. Concurrently, CAFs play a pivotal role in modulating the cell cycle, stemness, epithelial-mesenchymal transition (EMT), and resistance to targeted and chemoradiotherapy in HNSCC cells. This modulation occurs through interactions with secreted molecules or direct contact with the ECM or CAF. Co-culture and 3D models of tumour cells and other TME cell types allows to mimic the HNSCC tumour milieu and enable modulating tumour hypoxia and reprograming cancer stem cells (CSC). This review aims to provide an update on the development of HNSCC tumour models comprising CAFs to obtain better understanding of the interaction between CAFs and tumour cells, and for providing preclinical testing platforms of current and combination with emerging therapeutics.

Mechanisms and markers of malignant transformation of oral submucous fibrosis

Oral submucous fibrosis (OSF) is a chronic premalignant disease associated with betel quid chewing. Epidemiological studies indicate that there are approximately 5 million individuals suffering from OSF worldwide, with a concerning malignancy transformation rate of up to 4.2 %. When OSF progresses to oral squamous cell carcinoma (OSCC), the 5-year survival rate for OSCC drops to below 60 %. Therefore, early screening and diagnosis are essential for both preventing and effectively treating OSF and its potential malignant transformation. Numerous studies have shown that the malignant transformation of OSF is associated with various factors, including epigenetic reprogramming, epithelial-mesenchymal transition, hypoxia, cell cycle changes, immune regulation disturbances, and oxidative damage. This review article focuses on the unraveling the potential mechanisms underlying the malignant transformation of OSF, as well as the abnormal expression of biomarkers throughout this transformative process, with the aim of aiding early screening for carcinogenic changes in OSF. Furthermore, we discuss the significance of utilizing blood and saliva components from patients with OSF, along with optical diagnostic techniques, in the early screening of OSF malignant transformation.

The paradoxical role of transforming growth factor-β in controlling oral squamous cell carcinoma development

Transforming growth factor-β (TGF-β) is a multifunctional cytokine that plays a vital role in regulating cell growth, differentiation and survival in various tissues. It participates in a variety of cellular processes, including cell apoptosis, cell migration and evasion, and plays a paradoxical role in tumor genesis and development. In the early stage of tumor, TGF-β inhibits the occurrence of tumor by inhibiting cell proliferation and regulating cell apoptosis. In the advanced stage of tumor, TGF-β promotes tumor development and affects prognosis by promoting cell survival and proliferation, cell migration and invasion, participates in immune escape, etc. In this article, we will review the paradoxical role of TGF-β on the occurrence and development of oral squamous cell carcinoma.

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

An Immunohistochemical Analysis for Evaluating the Diagnostic Role of Myofibroblasts in Oral Squamous Cell Carcinoma using α-Smooth Muscle Actin Antibody

Background

One of the most common types of malignancies affecting the head and neck region is oral squamous cell carcinoma (OSCC). Little less is known about the role of myofibroblasts in the pathogenetic process of OSCC. Hence, we assessed the involvement of myofibroblasts in the invasive process of OSCC using α-SMA (α-smooth muscle actin) antibody.

Materials and Methods

Four study groups in total were organized as follows: 40 cases each of well-differentiated OSCC (WDOSCC), moderately differentiated OSCC (MDOSCC), poorly differentiated OSCC (PDOSCC), and controls make up Group 1, Group 2, Group 3, and Group 4, respectively. The percentage of α-SMA immunopositive cells and staining intensity (A) multiplied together to determine the final staining score (B). The final staining index was produced by multiplying staining intensity (A) by the proportion of immunopositive cells that were stained with α-SMA (B) (FSI). Score Zero was graded as Index Zero by FSI while scores One and Two received an Index Low rating, scores Three and Four an Index Moderate rating, and scores Six and Nine an Index High rating.

Results

Significantly higher expression of myofibroblast was observed in OSCC group in comparison with the control group. However; no significant difference in myofibroblast expression was observed while comparing different grades of OSCC.

Conclusion

We recommend using myofibroblasts as a stromal marker to track the severity and development of OSCC.

Phototoxicity of temoporfin-loaded cyclodextrin nanosponges in stroma-rich three-dimensional models of head and neck cancer

Photodynamic therapy is a multistage treatment, in which cancerous and precancerous cells are destroyed by light activation of a drug (photosensitizer). For a long time, high cellular uptake of the photosensitizer was an important indication of efficient PDT, while the role of photosensitizer penetration was unexplored. Recently, we have demonstrated that nanosponges based on hypercrosslinked β-cyclodextrin polymer (β-CDp) can increase drug penetration at the cost of their cellular uptake in multicellular spheroids, paving the way for studying the impact of penetration on PDT response. In the present work, we used β-CDp nanosponges to deliver temoporfin to the depth of stroma-rich head and neck cancer multicellular spheroids and then assess PDT response. Encapsulation of temoporfin in β-CDp nanosponges resulted in increased penetration and more uniform distribution of temoporfin in spheroids, however, was also associated with a two-fold reduction of cellular uptake compared to the free drug. Nevertheless, we demonstrated that β-CDp nanosponges possess similar PDT efficiency as the free drug in stroma-rich head and neck cancer multicellular spheroids. Overall, this study suggests that β-CDp nanosponges are a strong candidate for in vivo studies as they have fewer "off-target" effects while providing a similar therapeutic response.

Dual Role of Fibroblasts Educated by Tumour in Cancer Behavior and Therapeutic Perspectives

Tumours are complex systems with dynamic interactions between tumour cells, non-tumour cells, and extracellular components that comprise the tumour microenvironment (TME). The majority of TME's cells are cancer-associated fibroblasts (CAFs), which are crucial in extracellular matrix (ECM) construction, tumour metabolism, immunology, adaptive chemoresistance, and tumour cell motility. CAF subtypes have been identified based on the expression of protein markers. CAFs may act as promoters or suppressors in tumour cells depending on a variety of factors, including cancer stage. Indeed, CAFs have been shown to promote tumour growth, survival and spread, and secretome changes, but they can also slow tumourigenesis at an early stage through mechanisms that are still poorly understood. Stromal-cancer interactions are governed by a variety of soluble factors that determine the outcome of the tumourigenic process. Cancer cells release factors that enhance the ability of fibroblasts to secrete multiple tumour-promoting chemokines, acting on malignant cells to promote proliferation, migration, and invasion. This crosstalk between CAFs and tumour cells has given new prominence to the stromal cells, from being considered as mere physical support to becoming key players in the tumour process. Here, we focus on the concept of cancer as a non-healing wound and the relevance of chronic inflammation to tumour initiation. In addition, we review CAFs heterogeneous origins and markers together with the potential therapeutic implications of CAFs "re-education" and/or targeting tumour progression inhibition.

Construction and evaluation of a prognostic risk assessment model of gastric cancer by using hypoxia features

In this study, mRNA expression of gastric cancer tissue and clinical data of patients in TCGA-STAD dataset were used, together with the hypoxia-related gene sets in the MsigDB database, to screen hypoxia-related differentially expressed genes (DEGs) in GC. Thereafter, univariate and multivariate Cox regression analyses were carried out on hypoxia-related DEGs. The optimal feature genes related to prognosis were obtained to construct a prognostic risk assessment model. According to the model, the riskScore of GC patients was measured, and GC samples were assigned into high- and low-risk groups in accordance with the median riskScore. Based on the Kaplan-Meier curve and Receiver operating characteristic curve, validity of the prognostic risk assessment model was measured. Gene set enrichment analysis was performed on the two risk groups through Gene set enrichment analysis software. The results revealed that in the high-risk group, 9 signaling pathways were remarkably activated in several terms, like focal adhesion, extracellular matrix receptor interaction, Cell adhesion molecules cams, Cytokine-cytokine receptor interaction, TGF-beta signaling pathway, NOD-like receptor signaling pathway, JAK-STAT signaling pathway, Toll-like receptor signaling pathway and MAPK signaling pathway. In combination with riskScore and clinical factors, univariate and multivariate Cox regression analyses verified the independence of the model. Meanwhile, a nomogram was constructed to predict the 1-, 3- and 5-year survival of GC patients. The calibration curve indicated that the survival status predicted by the nomogram fitted better with actual survival status. On the whole, the prognostic risk model of GC on the basis of hypoxia-related genes demonstrated good predictive ability. It can provide more powerful technical support for clinicians to make prognostic determination and therapeutic plans.

Emerging Role of Autophagy in the Development and Progression of Oral Squamous Cell Carcinoma

Autophagy is a cellular catabolic process, which is characterized by degradation of damaged proteins and organelles needed to supply the cell with essential nutrients. At basal levels, autophagy is important to maintain cellular homeostasis and development. It is also a stress responsive process that allows the cells to survive when subjected to stressful conditions such as nutrient deprivation. Autophagy has been implicated in many pathologies including cancer. It is well established that autophagy plays a dual role in different cancer types. There is emerging role of autophagy in oral squamous cell carcinoma (OSCC) development and progression. This review will focus on the role played by autophagy in relation to different aspects of cancer progression and discuss recent studies exploring the role of autophagy in OSCC. It will further discuss potential therapeutic approaches to target autophagy in OSCC.

Biological implications of the immune factors in the tumour microenvironment of oral cancer

OBJECTIVE

The objective of this review is to decipher the biological implications of the immune factors in the tumour microenvironment in oral cancer. The restoration of balance between tumour tolerance and tumour eradication by the host immune cells is critical to provide effective therapeutic strategies.

DESIGN

The specific role of the stromal and the immune components in oral cancer was reviewed with a tailored search strategy using relevant keywords. The articles were retrieved from bibliometric databases indexed in PubMed, Scopus, and Embase. An in silico analysis was performed to identify potential drug candidates for immunotherapy, by accessing the Drug-Gene Interactions Database (DGIdb) using the rDGIdb package.

RESULTS

There is compelling evidence for the role of the cellular and extracellular components of the tumour microenvironment in inducing immunosuppression and progression of oral cancer. The druggable candidates specifically targeting the immune system are a viable option in the treatment of oral cancer as they can regulate the tumour microenvironment.

CONCLUSION

A complex interaction between the tumour and the immunological microenvironment influences the disease outcome in oral cancer. Targeting specific components of the immune system might be relevant, as immunotherapy may become the new standard of care for oral cancer.

Cancer-Associated Fibroblasts in Conversation with Tumor Cells in Endometrial Cancers: A Partner in Crime

A tumor cell carrying characteristic genomic alteration(s) exists within its host’s microenvironment. The tumor microenvironment (TME) renders holistic support to the tumor via cross-talk between tumor cells and three components of TME, immune components, vascular components, and fibroblast components. The tempero-spatial interaction of tumor cells with its microenvironment is the deterministic factor for tumor growth, progression, resistance to therapy, and its outcome in clinics. TME (1) facilitates proliferation, and the ensuing metastasis-associated phenotypes, (2) perturbs immune surveillance and supports tumor cells in their effort to evade immune recognition, and (3) actively participates in developing drug-induced resistance in cancer cells. Cancer-Associated Fibroblast (CAF) is a unique component of TME. CAF is the host mesenchyme immediately surrounding the tumor cells in solid tumors. It facilitates tumor growth and progression and participates in developing drug resistance in tumor cells by playing a critical role in all the ways mentioned above. The clinical outcome of a disease is thus critically contributed to by the CAF component of TME. Although CAFs have been identified historically, the functional relevance of CAF-tumor cell cross-talk and their influence on angiogenic and immune-components of TME are yet to be characterized in solid tumors, especially in endometrial cancers. Currently, the standard of care for the treatment of endometrial cancers is primarily guided by therapies directed towards the disease’s tumor compartment and immune compartments. Unfortunately, in the current state of therapies, a complete response (CR) to the therapy is still limited despite a more commonly achieved partial response (PR) and stable disease (SD) in patients. Acknowledging the limitations of the current sets of therapies based on only the tumor and immune compartments of the disease, we sought to put forward this review based on the importance of the cross-talk between CAF of the tumor microenvironment and tumor cells. The premise of the review is to recognize the critical role of CAF in disease progression. This manuscript presents a systemic review of the role of CAF in endometrial cancers. We critically interrogated the active involvement of CAF in the tumor compartment of endometrial cancers. Here we present the functional characteristics of CAF in the context of endometrial cancers. We review (1) the characteristics of CAF, (2) their evolution from being anti-tumor to pro-tumor, (3) their involvement in regulating growth and several metastasis-associated phenotypes of tumor cells, (4) their participation in perturbing immune defense and evading immune surveillance, and (5) their role in mediating drug resistance via tumor-CAF cross-talk with particular reference to endometrial cancers. We interrogate the functional characteristics of CAF in the light of its dialogue with tumor cells and other components of TME towards developing a CAF-based strategy for precision therapy to supplement tumor-based therapy. The purpose of the review is to present a new vision and initiate a thought process which recognizes the importance of CAF in a tumor, thereby resulting in a novel approach to the design and management of the disease in endometrial cancers.

3D Bioprinting for In Vitro Models of Oral Cancer: Toward Development and Validation

The tumor microenvironment (TME) of oral carcinomas has highly complex contents and a dynamic nature which is difficult to study using oversimplified two-dimensional (2D) cell culture systems. By contrast, three dimensional (3D) in vitro models such as spheroids, organoids, and scaffold-based constructs have been able to replicate tumors three-dimensionality and have allowed a better understanding of the role of various microenvironmental cues in the initiation and progression of cancer. However, the heterogeneity of TME cannot be fully reproduced by these traditional tissue engineering strategies since they are unable to control the organization of multiple cell types in a complex architecture. 3D bioprinting is an emerging field that can be leveraged to produce biomimetic and complex tissue structures. Bioprinting allows for controllable and precise placement of multicomponent bioinks composed of multiple biomaterials, different types of cells, and soluble factors according to the natural compartments of the target tissue, aiming to reproduce the equivalent of the complex tissue. As such, 3D bioprinting provides a unique opportunity to fabricate in vitro tumor models with a complexity similar to that of the in vivo oral carcinoma. This will facilitate a thorough investigation of cellular physiology, cancer progression, and anti-cancer drug screening with unprecedented control and reproducibility. In this review, we discuss the role of 3D bioprinting in reconstituting oral cancer, the prospects of application to fill the literature gap, and the challenges that need to be addressed in order to exploit this emerging technology for future work in oral cancer research.

Proteomic approaches to assist in diagnosis and prognosis of oral cancer

Introduction: Oral squamous cell carcinoma (OSCC) ranks among the top 10 leading causes of cancer worldwide, with 5-year survival rate of about 50%, high lymph node metastasis, and relapse rates. The OSCC diagnosis, prognosis, and treatment are mostly based on the clinical TNM classification. There is an urgent need for the discovery of biomarkers and therapeutic targets to assist in the clinical decision-making process.Areas covered: We summarize proteomic studies of the OSCC tumor, immune microenvironment, potential liquid biopsy sites, and post-translational modifications trying to retrieve information in the discovery and verification or (pre)validation phases. The search strategy was based on the combination of MeSH terms and expert refinement.Expert opinion: Untargeted combined with targeted proteomics are strategies that provide reliable and reproducible quantitation of proteins and are the methods of choice of many groups worldwide. Undoubtedly, proteomics has been contributing to the understanding of OSCC progression and uncovers potential candidates as biomarker or therapeutic targets. Nevertheless, none of these targets are available in the clinical practice yet. The scientific community needs to overcome the limitations by investing in robust experimental designs to strengthen the value of the findings, leveraging the translation of knowledge, and further supporting clinical decisions.

PTEN and α-SMA Expression and Diagnostic Role in Oral Submucous Fibrosis and Oral Squamous Cell Carcinoma with Concomitant Oral Submucous Fibrosis

Objectives

The diagnostic role and correlation between phosphatase and tensin homologue and alpha-smooth muscle actin in oral submucous fibrosis and oral squamous cell carcinoma with concomitant oral submucous fibrosis was analysed by this case control study. The mechanism by which phosphatase and tensin homologue controls myofibroblast expression was also evaluated.

Material and Methods

Overall, 10 normal mucosa, 30 oral submucous fibrosis (OSF) and 30 oral squamous cell carcinoma (OSCC) with OSF were stained immunohistochemically with phosphatase and tensin homologue (PTEN) and alpha-smooth muscle actin (α-SMA). Percentage positivity, pattern of expression was statistically compared using Pearson’s Chi-square and Fischer exact tests. The correlation between markers was analysed using Spearman correlation.

Results

OSF and OSCC affected males predominantly with majority below 40 years and above 40 years of age respectively. Percentage of PTEN positive cells was statistically significant with gender (P = 0.024) and α-SMA distribution of pattern showed a significant correlation with habits (P = 0.018). A significant decrease in nuclear PTEN positivity (P < 0.001) and a gradual increase in α-SMA cytoplasmic expression was noted from NM to OSF and OSCC. A statistically significant weak inverse correlation existed between PTEN and α-SMA.

Conclusions

A reduced phosphatase and tensin homologue expression in oral submucous fibrosis makes it more prone for malignant transformation. An increase in stromal desmoplasia modifies differentiation, invasive and proliferative capacity of tumour cells. As phosphatase and tensin homologue functions through P-Akt pathway, P-Akt with phosphatase and tensin homologue could be a therapeutic target.

AKT3 Is a Novel Regulator of Cancer-Associated Fibroblasts in Head and Neck Squamous Cell Carcinoma

Simple Summary

Cancer-associated fibroblasts (CAFs) promote epithelial-to-mesenchymal transition, angiogenesis, and immunosuppression, resulting in tumor progression. The PI3K-AKT pathway is known to play vital roles in various cellular activities, including proliferation, growth, metabolism, and survival. In the present study, we sought to identify the key regulator of CAFs in head and neck squamous cell carcinoma (HNSCC) and elucidated the vital roles of AKT3, one of the AKT isoforms, in CAFs. A loss-of-function approach revealed that AKT3 in CAFs promoted their myofibroblastic phenotype and immunosuppressive characteristics. Moreover, the infiltration of AKT3-positive CAFs into tumors was positively correlated with that of various immune cells and an unfavorable prognosis in HNSCC patients. Our findings suggest that AKT3 is a potential biomarker to evaluate the CAF activity and immunosuppressive microenvironment in HNSCC. Furthermore, AKT3 is a potential target for cancer therapy that inhibits the pro-tumoral function of CAFs.

Abstract

Cancer-associated fibroblasts (CAFs) play vital roles in tumor progression by promoting epithelial-to-mesenchymal transition, angiogenesis, and immunosuppression. In the present study, we sought to identify the key regulators of the pro-tumoral functions of CAFs in head and neck squamous cell carcinoma (HNSCC). mRNA expression data obtained from The Cancer Genome Atlas revealed that CAF-specific mRNA expression correlated with genes that relate to an immunosuppressive microenvironment in a HNSCC cohort. RNA sequencing of CAFs and normal fibroblasts isolated from HNSCC specimens identified 1127 differentially expressed genes (DEGs) and several upregulated pathways in CAFs. Among the 1127 DEGs, we identified 13 immune function-related genes and focused on AKT3 as a potential regulator of CAFs. The targeted depletion of AKT3 in CAFs revealed that AKT3 promotes their myofibroblastic phenotype. AKT3-transduced CAFs exhibited downregulated the expression of immunosuppressive cytokine genes, impairing T-cell suppression and pro-tumoral macrophage induction. The immunohistochemistry of 72 HNSCC patients showed that AKT3 expression in CAFs positively correlated with tumor infiltration by CAFs, tumor-associated macrophages, dendritic cells, and T cells. Moreover, AKT3 expression in CAFs was an independent prognostic factor for overall survival. In conclusion, AKT3 is a potential target for cancer therapy that inhibits the pro-tumoral function of CAFs and reverses CAF-mediated immunosuppression.

Molecular alterations in oral cancer using high-throughput proteomic analysis of formalin-fixed paraffin-embedded tissue

Loss of cell differentiation is a hallmark for the progression of oral squamous cell carcinoma (OSCC). Archival Formalin-Fixed Paraffin-Embedded (FFPE) tissues constitute a valuable resource for studying the differentiation of OSCC and can offer valuable insights into the process of tumor progression. In the current study, we performed LC-MS/MS-based quantitative proteomics of FFPE specimens from pathologically-confirmed well-differentiated, moderately-differentiated, and poorly-differentiated OSCC cases. The data were analyzed in four technical replicates, resulting in the identification of 2376 proteins. Of these, 141 and 109 were differentially expressed in moderately-differentiated and poorly differentiated OSCC cases, respectively, compared to well-differentiated OSCC. The data revealed significant metabolic reprogramming with respect to lipid metabolism and glycolysis with proteins belonging to both these processes downregulated in moderately-differentiated OSCC when compared to well-differentiated OSCC. Signaling pathway analysis indicated the alteration of extracellular matrix organization, muscle contraction, and glucose metabolism pathways across tumor grades. The extracellular matrix organization pathway was upregulated in moderately-differentiated OSCC and downregulated in poorly differentiated OSCC, compared to well-differentiated OSCC. PADI4, an epigenetic enzyme transcriptional regulator, and its transcriptional target HIST1H1B were both found to be upregulated in moderately differentiated and poorly differentiated OSCC, indicating epigenetic events underlying tumor differentiation. In conclusion, the findings support the advantage of using high-resolution mass spectrometry-based FFPE archival blocks for clinical and translational research. The candidate signaling pathways identified in the study could be used to develop potential therapeutic targets for OSCC.

Effect of stroma on the behavior of temoporfin-loaded lipid nanovesicles inside the stroma-rich head and neck carcinoma spheroids

Background

Despite the highly expected clinical application of nanoparticles (NPs), the translation of NPs from lab to the clinic has been relatively slow. Co-culture 3D spheroids account for the 3D arrangement of tumor cells and stromal components, e.g., cancer-associated fibroblasts (CAFs) and extracellular matrix, recapitulating microenvironment of head and neck squamous cell carcinoma (HNSCC). In the present study, we investigated how the stroma-rich tumor microenvironment affects the uptake, penetration, and photodynamic efficiency of three lipid-based nanoformulations of approved in EU photosensitizer temoporfin (mTHPC): Foslip^® (mTHPC in conventional liposomes), drug-in-cyclodextrin-in-liposomes (mTHPC-DCL) and extracellular vesicles (mTHPC-EVs).

Results

Collagen expression in co-culture stroma-rich 3D HNSCC spheroids correlates with the amount of CAFs (MeWo cells) in individual spheroid. The assessment of mTHPC loading demonstrated that Foslip^®, mTHPC-DCL and mTHPC-EVs encapsulated 0.05 × 10^− 15 g, 0.07 × 10^− 15 g, and 1.3 × 10^− 15 g of mTHPC per nanovesicle, respectively. The mid-penetration depth of mTHPC NPs in spheroids was 47.8 µm (Foslip^®), 87.8 µm (mTHPC-DCL), and 49.7 µm (mTHPC-EVs), irrespective of the percentage of stromal components. The cellular uptake of Foslip^® and mTHPC-DCL was significantly higher in stroma-rich co-culture spheroids and was increasing upon the addition of serum in the culture medium. Importantly, we observed no significant difference between PDT effect in monoculture and co-culture spheroids treated with lipid-based NPs. Overall, in all types of spheroids mTHPC-EVs demonstrated outstanding total cellular uptake and PDT efficiency comparable to other NPs.

Conclusions

The stromal microenvironment strongly affects the uptake of NPs, while the penetration and PDT efficacy are less sensitive to the presence of stromal components. mTHPC-EVs outperform other lipid nanovesicles due to the extremely high loading capacity. The results of the present study enlarge our understanding of how stroma components affect the delivery of NPs into the tumors.

Comparative analysis of the impact of e-cigarette vapor and cigarette smoke on human gingival fibroblasts

Human gingival fibroblasts (HGF) play a vital role in wound healing, oral cancer, and are among the first cells being exposed to e-cigarette vapor (eCV) or cigarette smoke (CS) during inhalation. Although the cell-damaging effect of CS has been well studied, the effects of eCV on gingival cells are still unclear. The aim of this in vitro study was to compare the effects of eCV and CS on HGF in terms of proliferation, metabolic activity, cell death, and formation of reactive oxygen species (ROS). After 24 h cell numbers in CS-exposed cells in contrast to eCV-exposed cells were significantly decreased compared to the control. At later points in time, such differences could no longer be observed. Compared to the control, HGF stimulated with eCV showed a significantly higher metabolic activity 1 h, 24 h, and 48 h after exposure. 24 h after exposure, the metabolic activity was increased in both test groups. No caspase 3/7 activation nor significant differences in the amount of apoptosis/necrosis among the groups were seen. Only in CS-exposed cells ROS formation was increased at 1 h, 3 h, and 6 h after exposition. In conclusion, when compared to conventional CS, a less harmful effect of eCV on HGF can be assumed.

Cancer-Associated Fibroblast Density, Prognostic Characteristics, and Recurrence in Head and Neck Squamous Cell Carcinoma: A Meta-Analysis

Introduction

The progression and clinical course of head and neck squamous cell carcinoma (HNSCC) relies on complex interactions between cancer and stromal cells in the tumor microenvironment (TME). Among the most abundant of these stromal cells are cancer-associated fibroblasts (CAFs). While their contribution to tumor progression is widely acknowledged, and various CAF-targeted treatments are under development, the relationship between CAF density and the clinicopathologic course of HNSCC has not been clearly defined. Here we examine the published evidence investigating the relationship of cancer-associated fibroblasts to local recurrence and indicators of prognostic significance in HNSCC.

Methods

We conducted a meta-analysis of existing publications that compare the relationship between CAF density, local recurrence, and clinically significant pathologic criteria of disease development (T stage, nodal positivity, clinical stage, vascular invasion, perineural invasion, Ki67 expression, and differentiation). Thirteen studies met the selection criteria, providing a total study population of 926 patients. Forest plots and risk ratios were generated to illustrate overall relationships.

Results

Higher CAF density within the tumor microenvironment is associated with advanced T stage, nodal infiltration, clinical stage, vascular invasion, perineural invasion, Ki67 expression, and differentiation (p <0.05). High CAF density is also associated with increased rates of local recurrence (p <0.001).

Conclusions

Across multiple studies, increased CAF density is correlated with histopathological criteria of poor prognosis in HNSCC. These findings highlight that CAFs may play a pivotal role in HNSCC development and progression. Staining for CAFs may represent a valuable addition to current pathologic analysis and help to guide prognosis and treatment. Understanding the mechanisms by which CAFs reciprocally interact with cancer cells will be crucial for optimization of TME-focused treatment of HNSCC.

Hedgehog pathway activation in oral squamous cell carcinoma: cancer-associated fibroblasts exhibit nuclear GLI-1 localization

The purpose of this study was to evaluate the expression of Hedgehog (HH) signaling molecules (SHH and GLI-1) by cancer-associated fibroblasts (CAF) in oral squamous cell carcinoma (OSCC). Immunohistochemistry was used to detect molecular HH signaling and CAF-related protein expression, including α-SMA and S100A4, in 70 samples of human OSCC. The colocalization of α-SMA and S100A4 with SHH was also evaluated by double-staining. In vitro study was performed using primary normal oral fibroblast (NOF) and CAF through immunofluorescence and Western Blot for CAF-proteins, SHH, and GLI-1. Forty-five cases (64.28%) were positive for α-SMA exclusively in tumor stroma, and S100A4 was identified in the cytoplasm of CAFs in 94.28% (n = 66) of the cases. With respect to stromal cells, 64 (91.43%) OSCC cases were positive for SHH, and 31 were positive for GLI-1 (44.29%); positive correlations were found between SHH and α-SMA (p < 0.0001, φ = 0.51), as well as between SHH and S100A4 (p = 0.087, φ = 0.94). Protein expression of SHH and GLI-1 was observed in primary CAFs and NOFs. Although SHH was found to be localized in the cellular cytoplasm of both cell types, GLI-1 was present only in the nuclei of CAF. Our results indicate that CAFs are not only potential sources of HH ligands in tumor stroma, but may also respond to HH signaling through nuclear GLI-1 activation. We further observed that elevated SHH expression by OSCC cells was associated with higher CAF density, reinforcing the chemoattractant role played by these molecules.

Eukaryotic translation elongation factor 1δ, N-terminal propeptide of type I collagen and cancer-associated fibroblasts are prognostic markers of oral squamous cell carcinoma patients

OBJECTIVE

Identifying markers that influence oral squamous cell carcinoma (OSCC) prognosis is a fundamental strategy to improve the overall survival of patients. Markers such as eukaryotic translation elongation factor 1δ (EEF1D), fascin, N-terminal propeptide of type I collagen (PINP), and cancer-associated fibroblasts (CAFs) have been noticed in OSCCs and their levels are closely related to the prognosis of tumors. Our aim was to confirm the role of those markers in OSCC prognosis.

STUDY DESIGN

Immunohistochemistry was performed in 90 OSCC specimens. The associations between clinicopathologic features and expression of markers were assessed by χ² test. Kaplan-Meier curves and univariate and multivariate Cox regression models were used for survival analysis. Markers were analyzed individually and in combination.

RESULTS

High expression of EEF1D (P = .017) and PINP (P = .02) and abundant density of CAFs in tumor stroma (P = .005) predicted significantly poor survival in OSCC patients. Multivariate analysis revealed that all 3 parameters are individually independent prognostic factors of OSCC patients, and their combination improved the discrimination of patients at high risk for poor survival.

CONCLUSIONS

Our results suggested that the expression of EEF1D and PINP and the density of CAFs might influence the survival of patients with OSCC.

Comparison of expression of myofibroblasts in normal oral mucosa, oral epithelial dysplasia, and oral squamous cell carcinoma using α-SMA and vimentin: An immunohistochemical study

Background:

Myofibroblasts are thought to play critical roles in inflammation, growth, repair, premalignancy, and malignancy. This study was done to evaluate, compare and co- relate the progressive increase in the immunohistochemical expression of myofibroblasts in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma (OSCC). To compare and co-relate the expression of myofibroblasts in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma. To co-relate the progressive increase in myofibroblasts expression in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma.

Materials and Method:

Forty-nine paraffin-embedded tissue blocks with 7 cases of normal oral mucosa, 21 cases of epithelial dysplasia, and 21 diagnosed cases of OSCCs were studied. The samples were subjected to heat-induced antigen retrieval methods followed by staining using primary mouse monoclonal antibodies against α-smooth muscle actin (SMA) and vimentin. Staining index of all the sections was calculated. Statistical analysis was performed using the Kruskal–Wallis test, Mann–Whitney U test, and Chi-square test. Values of P less than or equal to 0.05 (P ≤ 0.05) were considered statistically significant.

Results:

Statistically significant staining index was obtained by α-SMA and vimentin between normal oral mucosa, epithelial dysplasia, and OSCC.

Conclusion:

Myofibroblast may play a role only during initial tumorigenesis that is the conversion of severe dysplasia into OSCC.

Myofibroblasts as important diagnostic and prognostic indicators of oral squamous cell carcinoma: An immunohistochemical study in normal oral mucosa, epithelial dysplasia, and oral squamous cell carcinoma

BACKGROUND

Cancer invasion is a critical step for tumor growth and its progression. The focus on epithelial changes is shifting to increasing recognition that the microenvironment makes significant contributions to tumor progression. Stromal myofibroblasts play an important role in tumor invasion and metastasis due to its ability to modify the extracellular matrix. Based on this literary evidence, we carried out an immunohistochemical study to observe the expression of myofibroblasts in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC).

AIM

The aim of the study was to evaluate, compare, and correlate the presence of myofibroblasts in normal oral mucosa, oral epithelial dysplasia, and OSCC and to observe different patterns of myofibroblast arrangement using alpha-smooth muscle actin (α-SMA) as a marker, Thus assisting in early diagnosis, treatment, and prognosis of oral carcinomas.

MATERIALS AND METHODS

Thirty-six cases including 12 cases of OSCC, 12 cases of epithelial dysplasia, and 12 cases of normal oral mucosa were stained with hematoxylin and eosin to confirm the diagnosis and immunohistochemically using α-SMA antibody. The slides were evaluated for positivity and intensity of staining.

STATISTICAL ANALYSIS

The result was subjected to statistical analysis using Fisher's exact test.

RESULTS

α-SMA expression in the stroma of squamous cell carcinoma was greater than its expression in epithelial dysplasia and normal oral mucosa.

Evaluation of Stromal Myofibroblasts in Laryngeal Dysplasia and Invasive Squamous Cell Carcinoma

Malignant tumors consist of both carcinoma cells and tumor associated host cells. Host cells has started to receive more attention regarding their role in tumor progression such as invasion and metastasis. Fibroblasts that are incorporated in the tumoral stroma are called as peritumoral fibroblasts, reactive stroma, cancer-related fibroblasts or myofibroblasts. In general fibroblasts next to nich of cancer cells express alpha-smooth muscle actin (α-SMA) which is an important marker for differentiated myofibroblasts. Our aim is to investigate the role of α-SMA positive myofibroblasts in the development and progression of laryngeal carcinoma. The proportion of α-SMA positive myofibroblasts are scored from (1 +) to 3( +) in laryngeal dysplasia (n = 17) and microinvasive and invasive squamous cell carcinoma (n = 66). α-SMA expression in invasive carcinoma and dysplasia was analyzed statistically. No stromal myofibroblast was detected in mild dysplasia (score 0). Among 12 cases of moderate-severe dysplasia, in only 3 cases low α-SMA expression (score 1) was observed and in 9 cases there were no stromal myofibroblasts (score 0) were. In most cases of invasive carcinoma, high α-SMA expression (score 2, 3) was seen. α-SMA positive stromal myofibroblasts were significantly higher in invasive laryngeal squamous cell carcinoma compared to dysplasia (p < 0.05). Results of our study suggested that α-SMA positive stromal myofibroblasts play an important role in creating the permissive environment for tumor invasion in laryngeal squamous cell carcinoma. According to this data, we think that the presence of stromal myofibroblasts might be used as a helpful criterion in the differential diagnosis of true invasion and pseudoinvasion.

Stroma-Rich Co-Culture Multicellular Tumor Spheroids as a Tool for Photoactive Drugs Screening

Conventional 3D multicellular tumor spheroids of head and neck squamous cell carcinoma (HNSCC) consisting exclusively of cancer cells have some limitations. They are compact cell aggregates that do not interact with their extracellular milieu, thus suffering from both insufficient extracellular matrix (ECM) deposition and absence of different types of stromal cells. In order to better mimic in vivo HNSCC tumor microenvironment, we have constructed a 3D stroma-rich in vitro model of HNSCC, using cancer-associated MeWo skin fibroblasts and FaDu pharynx squamous cell carcinoma. The expression of stromal components in heterospheroids was confirmed by immunochemical staining. The generated co-culture FaDu/MeWo spheroids were applied to study penetration, distribution and antitumor efficacy of photoactive drugs such as Temoporfin and Chlorin e6 used in the photodynamic therapy flow cytometry and fluorescence microscopy techniques. We also investigated the distribution of photodiagnostic agent Indocyanine Green. We demonstrated that the presence of stroma influences the behavior of photoactive drugs in different ways: (i) No effect on Indocyanine Green distribution; (ii) lower accumulation of Chlorin e6; (iii) better penetration and PDT efficiency of Temoporfin. Overall, the developed stroma-rich spheroids enlarge the arsenal of in vitro pre-clinical models for high-throughput screening of anti-cancer drugs.

Ki67, CD105 and α-smooth muscle actin expression in disease progression model of oral submucous fibrosis

AIM

The aim of this study was to investigate the expression of Ki67, CD105 and α-smooth muscle actin (α-SMA) expression in oral submucous fibrosis (OSF) and oral squamous cell carcinoma in the background of OSF (OSCC-SMF).

METHODS

The study was carried out on paraffin-embedded tissues of 30 normal oral mucosa (NOM), 50 OSF cases and 105 OSCC-SMF. The immunohistochemistry was carried out to evaluate the expression of Ki67, CD105 and α-SMA antigen.

RESULTS

Ki67 labelling index (LI), CD105 and α-SMA expression showed increasing trend from NOM, low-risk epithelial dysplasia (LRED), high-risk epithelial dysplasia (HRED), well-differentiated squamous cell carcinoma (WDSCC), moderately differentiated squamous cell carcinoma to poorly differentiated squamous cell carcinoma. However, there was no significant difference of α-SMA expression between HRED and WDSCC. In OSCC-SMF, Ki67 LI, CD105 and α-SMA were significantly higher in advanced clinical TNM stage, metastasis and less than 3 years patient survival as compared with early clinical TNM stage, non-metastasis and 3 years or more patient survival.

CONCLUSION

Ki67 LI, α-SMA and CD105 expression alone or together correspond with the disease progression model of SMF. Hence, expression of these markers can be used as a predictive marker of clinical outcome of OSCC-SMF.

Oral cancer-associated fibroblasts predict poor survival: Systematic review and meta-analysis

OBJECTIVES

To perform systematic review and meta-analysis on correlations between cancer-associated fibroblasts (CAFs) and the risk of death for patients with oral squamous cell carcinoma.

SUBJECTS AND METHODS

English literature (1966-2018) was systematically analyzed for studies that immunohistochemically assessed CAF density by alpha-smooth muscle actin and presented 5 year survival rates by Kaplan-Meier plots. Mean age of patients, proportion of male/female patients, and male/female majority (>50% male/female patients) per study were also collected. Significance level for statistical models was p < 0.05.

RESULTS

Meta-analysis comprised 11 studies/1,040 patients. Univariate Cox regressions showed that high CAF density was a negative prognostic factor in studies with female and male majority [OR 5.329 (95% CI 3.223-8.811), p < 0.001, and OR 2.208 (95% CI 1.717-2.839), p < 0.001, respectively]. High CAF density with male majority was associated with a more favorable prognosis [OR 0.996 (95% CI 0.979-1.013), p < 0.001]. Multivariate Cox regressions showed that death risk was significantly higher among patients with high CAF density compared to low CAF [OR 2.741 (95% CI 2.220-3.384) p < 0.001]. High mean age and male proportion were significantly protective [OR 0.940 (95% CI 0.925-9.955), p < 0.001, OR 0.125 (95% CI 0.018-0.867), p = 0.035), respectively].

CONCLUSIONS

CAFs increased death risk, male majority, and higher mean age were protective. A clinically validated cutoff for CAF density could serve as a reliable prognostic tool.

Effect of tumor microenvironment on pathogenesis of the head and neck squamous cell carcinoma: a systematic review

The tumor microenvironment (TME) is comprised of many different cell populations, such as cancer-associated fibroblasts and various infiltrating immune cells, and non-cell components of extracellular matrix. These crucial parts of the surrounding stroma can function as both positive and negative regulators of all hallmarks of cancer development, including evasion of apoptosis, induction of angiogenesis, deregulation of the energy metabolism, resistance to the immune detection and destruction, and activation of invasion and metastasis. This review represents a summary of recent studies focusing on describing these effects of microenvironment on initiation and progression of the head and neck squamous cell carcinoma, focusing on oral squamous cell carcinoma, since it is becoming clear that an investigation of differences in stromal composition of the head and neck squamous cell carcinoma microenvironment and their impact on cancer development and progression may help better understand the mechanisms behind different responses to therapy and help define possible targets for clinical intervention.

Cancer associated fibroblasts sculpt tumour microenvironment by recruiting monocytes and inducing immunosuppressive PD-1+ TAMs

Fibroblasts turn into cancer associated fibroblasts (CAFs) in the tumour microenvironment. CAFs have recently attracted attention for their function as a regulator of immune cell recruitment and function in addition to their tumour-promoting roles. In this study, we aimed to determine the role of CAFs on monocyte recruitment and macrophage polarization in breast cancer. CAFs, which were α-SMA expressing fibroblasts in contrast to normal fibroblasts (NFs), effectively recruited monocytes. Recruitment of monocytes by CAFs might be mediated by monocyte chemotactic protein-1 (MCP-1) as well as stromal cell-derived factor-1 (SDF-1) cytokines. CAFs differentiated the recruited monocytes into M2-like macrophages which are capable of exerting their immunosuppressive roles via the PD-1 axis. CAF-educated monocytes exhibited strong immune suppression unlike NF-educated monocytes and enhanced the motility/invasion of breast cancer cells in addition to increasing the expressions of epithelial–mesenchymal transition (EMT)-related genes and vimentin protein in cancer cells. CAF-educated M1 macrophages displayed increased expression of M2 markers and production of anti-inflammatory cytokine IL-10 in contrast to decreased production of pro-inflammatory cytokine IL-12 compared with control M1 macrophages; suggesting that CAFs were also able to induce the trans-differentiation of M1 macrophages to M2 macrophages. We then investigated the relationship between the infiltration of CAFs and tumour associated macrophages (TAMs) using tissue samples obtained from breast cancer patients. High grade of CAFs significantly correlated with the number of TAMs in human breast cancer tissue samples. It was also associated with higher Ki-67 proliferation index, and higher tumour volume. This result is in line with our finding of increased breast cancer cell proliferation due to the effects of CAF-educated monocytes in vitro. Our results concluded that CAFs play pivotal roles in sculpturing the tumour microenvironment in breast cancer, and therapeutic strategies to reverse the CAF-mediated immunosuppressive microenvironment should be taken into consideration.

Extracellular vesicles derived from cancer-associated fibroblasts induce the migration and invasion of oral squamous cell carcinoma

As one of the most abundant constituents of the tumour microenvironment (TME), cancer-associated fibroblasts (CAF) display critical roles during tumour progression and metastasis. Multiple classes of molecules including growth factors, cytokines, proteases and extracellular matrix proteins, are produced by CAF to act as mediators of the stroma-tumour interactions. One of the main channels for this communication is associated with extracellular vesicles (EV), which are secreted particles loaded with protein and genetic information. In this study, we evaluated the effects of EV derived from CAF primary human cell lines (n = 5) on proliferation, survival, migration, and invasion of oral squamous cell carcinoma (OSCC) cells. As controls, EV from human primary-established normal oral fibroblasts (NOF, n = 5) were used. Our in vitro assays showed that CAF-EV significantly induces migration and invasion of OSCC cells and promote a disseminated pattern of HSC-3 cell invasion in the 3D organotypic assay. Furthermore, gene expression analysis of EV-treated cancer cells revealed changes in the pathways associated with tumour metabolism and up-regulation of tumour invasion genes. Our findings suggest a significant role of CAF-EV in promoting the migration and invasion of OSCC cells, which are related to the activation of cancer-related pathways.

A Comparative Immunohistochemical Study of Presence and Distribution Pattern of Stromal Myofibroblast in Oral Dysplasia and in Different Grades of Oral Squamous Cell Carcinoma

Aims and Objectives:

Squamous cell carcinoma (SCC) is a common oral malignancy with a poor survival rate. Early tumorigenesis is marked by transdifferentiation of fibroblasts to myofibroblasts (MFs), which is supported by growth factors and cytokines expressed by tumor cells. The expression of alpha-smooth muscle actin (αSMA) marker correlates with the activation of MFs. This study was undertaken to compare the frequency and distribution of αSMA immunoexpression in oral epithelial dysplasia (OED) and OSCC.

Materials and Methods:

This study was conducted on samples collected from patients with oral epithelial dysplasia and oral SCC who visited Rajarajeswari Dental College and Hospital, Bengaluru. Tissue sections were subjected to Immunohistochemistry using αSMA marker, and cells were counted. The obtained data was subjected to Kruskal–Wallis test and Mann–Whitney U-test.

Results:

On performing Kruskal–Wallis test and Mann–Whitney U-test between the three groups (normal oral mucosa, OED, and OSCC) statistically significant result was found in the frequency between OED and OSCC and between normal tissue and OSCC. On comparing the distribution pattern, statistically significant result was found between OED and OSCC and between normal tissue and OSCC.

Conclusion:

The expression of MFs increases as the disease progresses from high-grade epithelial dysplasia to invasive OSCC. Poorly differentiated SCC showed more attendance of positive MFs in the stroma than other grades of OSCC. The rise in the number of αSMA-positive MFs and change in distribution pattern in OSCC can be associated with tumor invasive characteristics. Thus, the proliferation of MFs may be used as a stromal marker of premalignancy and malignancy.

Myofibroblasts in oral potentially malignant disorders: Is it related to malignant transformation?

In oral cancer, acquisition of α-smooth muscle actin (α-SMA)-positive fibroblasts, known as myofibroblasts or carcinoma-associated fibroblasts (CAF), is an important event for progression and metastasis. However, the contribution of myofibroblasts in oral potentially malignant disorders (OPMD) remains controversial. This systematic review provides evidence that immunodetection of myofibroblasts may identify oral submucous fibrosis (OSMF) with high risk of malignant transformation, but does not represent an auxiliary tool to predict the malignant potential of leukoplakia and erythroplakia, the most common OPMD.

Anaplastic transition within the cancer microenvironment in early-stage oral tongue squamous cell carcinoma is associated with local recurrence

The cancer microenvironment (CME) promotes malignant progression of cancer cells by stimulating cell growth, migration and invasion. Cancer-associated fibroblasts (CAFs), prominent features of the CME, interact directly with cancer cells and facilitate epithelial-mesenchymal transition (EMT). The present study examined the spatial distribution of CAFs and EMT on cancer cells in patients with early-stage tongue squamous cell carcinoma (TSCC) and their association with local recurrence. The present study included 14 patients with early-stage TSCC who had undergone glossectomy between 2006 and 2015, of which 7 experienced local recurrence (LR group) and 7 did not (control group). Multiple immunofluorescent analysis (MIA) of PCNA, αSMA, vimentin, E-cadherin and cytokeratin 14 (CK14) was performed on slides obtained from surgical specimens to identify the expression of various cell-specific markers. The number of CAFs in the CME was significantly increased in the LR group (P=0.001). Furthermore, the neighbouring cancer cells were positive for vimentin expression, indicating EMT. However, the present study also identified concurrent expression of CK14 in all vimentin-positive cancer cells, whilst epithelial markers, including E-cadherin, were expressed in certain vimentin-positive cancer cells. Concurrent expression of CK14 and vimentin is not defined as EMT or partial EMT. Therefore, the present study proposed a novel mechanism of anaplastic transition (APT), in which epithelial cancer cells concurrently develop mesenchymal features, which is achieved by pathways other than EMT. APT is characterized such that epithelial cancer cells differentiate into more primitive states, which is different from EMT or partial EMT, and it may be associated with LR. The concept aids in improving knowledge regarding tumor recurrence in patients with early-stage TSCC.

An Immunohistochemical and Polarizing Microscopic Study of the Tumor Microenvironment in Varying Grades of Oral Squamous Cell Carcinoma

BACKGROUND

Invasion of epithelial cells into the connective tissue brings about massive morphological and architectural changes in the underlying stroma. Myofibroblasts reorganize the stroma to facilitate the movement of tumor cells leading to metastasis. The aim of this study was to determine the number and pattern of distribution of myofibroblasts and the qualitative and quantitative change that they cause in the collagen present in the stroma in various grades of oral squamous cell carcinoma (OSCC).

METHODS

The study was divided into two groups with group I (test group, 65 cases) consisting of 29 cases of well-differentiated squamous cell carcinoma, 25 moderately differentiated SCC, and 11 poorly differentiated SCC, and group II (control group) consisting of 11 cases of normal mucosa. Sections from each sample were stained with anti-α-smooth muscle actin (α-SMA) antibodies, hematoxylin and eosin, and Picrosirius red. Several additional sections from each grade of OSCC were stained with Masson's trichrome to observe the changes in collagen. For the statistical analysis, Fisher's exact test, Tukey's post hoc honest significant difference test, ANOVA, and the chi-square test were used, and p < .05 was considered statistically significant.

RESULTS

As the tumor stage progressed, an increase in the intensity α-SMA expression was seen, and the network pattern dominated in more dedifferentiated carcinomas. The collagen fibers became thin, loosely packed, and haphazardly aligned with progressing cancer. Additionally, the mean area fraction decreased, and the fibers attained a greenish yellow hue and a weak birefringence when observed using polarizing light microscopy.

CONCLUSIONS

Myofibroblasts bring about numerous changes in collagen. As cancer progresses, there isincrease in pathological collagen,which enhances the movement of cells within the stroma.

Ki67, CD105, and α-SMA expression supports the transformation relevant dysplastic features in the atrophic epithelium of oral submucous fibrosis

Background

The grading of oral epithelial dysplasia is not possible in the atrophic epithelium of oral submucous fibrosis (OSMF). Recently, we found that features such as increased basal cell layer hyperplasia, abnormal superficial mitosis, increased nuclear-cytoplasmic ratio, increased nuclear size, and hyperchromasia represent transformation-relevant dysplastic features in the atrophic epithelium of OSMF. The presence of these features can be considered a high-risk feature for patients. However, these findings have not been tested and authenticated using markers relevant to oral carcinogenesis.

Method

Paraffin-embedded tissues from 30 normal oral mucosa (NOM) and 50 OSMF were retrieved from 2008 to 2016 and subjected to immunohistochemical expression using Ki67, CD105 and α-SMA antibodies.

Results

Ki67 LI showed significant increases from NOM (12.47±2.34) to LRED (23.47±3.75) to HRED (34.31±7.31) (<0.0001). Similarly, MVD was increased significantly from NOM (3.53±5.17) to LRED (27.57±12.25) to HRED (46.18±12.55) (p<0.0001). The expression of α-SMA was significantly increased from LRED (0.21±0.41) to HRED (1.13±0.56) (<0.0001). The Ki67 LI and α-SMA; MVD and α-SMA; and Ki67Ki67 LI and MVD in NOM, LRED and HRED showed a statistically significant positive correlation (P<0.0001). The increase in Ki67 LI was directly proportional to MVD and α-SMA expression from NOM to LRED to HRED (P<0.0001). The connective tissue stroma of NOM lacks α-SMA expression. Mild myofibroblast expression was noted in 4 cases of LRED (14.28%) and in 18 cases of HRED (81.81%). Moderate expression was noted only in 4 cases of HRED (22.22%).

Conclusion

Ki67 LI, CD105, and α-SMA expression showed significant differences between normal, LRED and HRED. These findings further support that features such as increased basal cell layer hyperplasia, abnormal superficial mitosis, increased nuclear-cytoplasmic ratio, and hyperchromasia could be transformation-relevant dysplastic features.

Tumor microenvironment - Unknown niche with powerful therapeutic potential

Head and neck squamous cell carcinomas (HNSCC) are in a group of cancers that are the most resistant to treatment. The survival rate of HNSCC patients has been still very low since last 20 years. The existence of relationship between oncogenic and surrounding cells is probably the reason for a poor response to treatment. Fibroblasts are an important element of tumor stroma which increases tumor cells ability to proliferate. Another highly resistance, tumorigenic and metastatic cell population in tumor microenvironment are cancer initiating cells (CICs). The population of cancer initiating cells can be found regardless of differentiation status of cancer and they seem to be crucial for HNSCC development. In this review, we describe the current state of knowledge about HNSCC biological and physiological tumor microenvironment.

The Influence of Breast Tumour-Derived Factors and Wnt Antagonism on the Transformation of Adipose-Derived Mesenchymal Stem Cells into Tumour-Associated Fibroblasts

Within the tumour stroma, a heterogeneous population of cell types reciprocally regulates cell proliferation, which considerably affects the progression of the disease. In this study, using tumour conditioned medium (TCM) derived from breast tumour cell lines - MCF7 and MDA MB 231, we have demonstrated the differentiation of adipose-derived mesenchymal stem cells (ADSCs) into tumour-associated fibroblasts (TAFs). Since the Wnt signalling pathway is a key signalling pathway driving breast tumour growth, the effect of the Wnt antagonist secreted frizzled-related protein 4 (sFRP4) was also examined. The response of ADSCs to TCM and sFRP4 treatments was determined by using cell viability assay to determine the changes in ADSC viability, immunofluorescence for mesenchymal markers, glucose uptake assay, and glycolysis stress test using the Seahorse Extracellular Flux analyser to determine the glycolytic activity of ADSCs. ADSCs have been shown to acquire a hyper-proliferative state, significantly increasing their number upon short-term and long-term exposure to TCM. Changes have also been observed in the expression of key mesenchymal markers as well as in the metabolic state of ADSCs. SFRP4 significantly inhibited the differentiation of ADSCs into TAFs by reducing cell growth as well as mesenchymal marker expression (cell line-dependent). However, sFRP4 did not induce further significant changes to the altered metabolic phenotype of ADSCs following TCM exposure. Altogether, this study suggests that the breast tumour milieu may transform ADSCs into a tumour-supportive phenotype, which can be altered by Wnt antagonism, but is independent of metabolic changes.

Cancer-associated fibroblasts promote an immunosuppressive microenvironment through the induction and accumulation of protumoral macrophages

Stromal cells in the tumor microenvironment (TME) closely interact with tumor cells and affect tumor cell behavior in diverse manners. We herein investigated the mechanisms by which cancer-associated fibroblasts (CAFs) affect the functional polarization of tumor-associated macrophages (TAMs) in oral squamous cell carcinoma (OSCC) in vitro and in human cancer samples. The expression of CD68, CD14, CD163, CD200R, CD206, HLA-G, CD80, and CD86 was higher in CD14-positive cells co-cultured with the culture supernatants of CAFs established from OSCC specimens (CAF-educated cells) than in control cells. The gene expression level of ARG1, IL10, and TGFB1 was increased in CAF-educated cells. CAF-educated cells suppressed T cell proliferation more strongly than control cells, and the neutralization of TGF-β IL-10, or arginase I significantly restored T cell proliferation. We then investigated the relationship between the infiltration of CAFs and TAMs using tissue samples obtained from patients with OSCC. The infiltration of CAFs was associated with the numbers of CD68-positive and CD163-positive macrophages. It also correlated with lymphatic invasion, vascular invasion, lymph node involvement, and the TNM stage. The infiltration of CAFs was identified as an independent prognostic factor in OSCC. Our results indicate that CAFs play important roles in shaping the tumor immunosuppressive microenvironment in OSCC by inducing the protumoral phenotype of TAMs. Therapeutic strategies to reverse CAF-mediated immunosuppression need to be considered.

Leukemia inhibitory factor produced by fibroblasts within tumor stroma participates in invasion of oral squamous cell carcinoma

The interaction between cancer cells and the cancer stroma plays a crucial role in tumor progression and metastasis in diverse malignancies, including oral cancer. However, the mechanism underlying this interaction remains incompletely elucidated. Here, to investigate the interaction between oral cancer cells and fibroblasts, which are major cellular components of the tumor stroma, we conducted an in vitro study by using human oral squamous cell carcinoma (OSCC) cell lines and normal human dermal fibroblasts (NHDFs). The results of transwell assays revealed that the migration and invasion of 2 OSCC cell lines, HO1-N-1 and HSC3, were markedly stimulated upon coculturing with NHDFs. To investigate the factors that promote tumor invasion, we isolated NHDFs from cocultures prepared with HO1-N-1 cells and performed microarray analysis. Among the various genes that were upregulated, we identified the gene encoding leukemia inhibitory factor (LIF), and we focused on LIF in further analyses. We confirmed that all OSCC-derived conditioned media potently upregulated LIF expression in NHDFs, and the results of our transwell analysis demonstrated that NHDF-induced OSCC migration and invasion were inhibited by LIF-neutralizing antibodies. Furthermore, immunohistochemical analysis of patient samples revealed that in 44 out of 112 OSCC cases, LIF was expressed in the tumor stroma, particularly in cancer-associated fibroblasts (CAFs), and, notably, clinicopathological analyses confirmed that LIF expression in CAFs was significantly correlated with increased depth of tumor invasion. Collectively, our results suggest that OSCC stimulates fibroblasts to produce LIF, which, in turn, participates in cancer-cell invasion. Our finding offers a potential therapeutic strategy targeting the cancer stroma for the treatment of OSCC patients.

The heterogenic tumor microenvironment of hepatocellular carcinoma and prognostic analysis based on tumor neo-vessels, macrophages and α-SMA

The present study was performed to quantify tumor neo-vessels, macrophages and fibroblasts in the tumor microenvironment of hepatocellular carcinoma (HCC) and explore the prognostic factors of HCC. The distribution of tumor neo-vessels, macrophages and fibroblasts was quantified by immunohistochemistry and inverted microscopy with the CRi Nuance multispectral imaging system, and the correlation of these parameters with the clinico-pathological characteristics and overall survival of the patients was analyzed. The number of tumor neo-vessels and macrophages, and density of the fibroblasts, as calculated by the thickness of the tumor stroma in the tumor microenvironment, ranged from 51-429 (median, 218), 110-555 (median, 259) and 35.6-555.5 µm (median, 247.0), respectively. Using the median values as a cutoff, the cases were stratified into high- and low-density groups. Survival analysis demonstrated that the high-density groups regarding macrophages (χ²=5.249, P=0.022) and fibroblasts (χ²=18.073, P<0.001) had a significantly shorter disease-free survival (DFS) than the low-density groups. The high-density tumor neo-vessel group had a shorter DFS with a median of 5 months than the low-density group with a median of 7 months; however, there was no statistical significance between these two groups (χ²=1.663, P=0.197). Regarding the above three stromal components combined, all of the cases were classified into low-, middle- and high-density groups. Survival analysis demonstrated that the high-density group of stromal components had a shorter DFS than the other two groups with a median of 3 months (χ²=14.439, P=0.001). Multivariate analysis by Cox regression indicated that cirrhosis, metastasis stage, as well as macrophage and fibroblast density were independent prognostic factors. In conclusion, the key elements in the tumor microenvironment, including tumor neo-vessels, macrophages and fibroblasts, were heterogenic in HCC tissues and have significant roles in HCC invasion and metastasis. Stromal components are associated with the prognosis of patients with HCC; the higher the density of stromal components, the poorer the prognosis of patients with HCC.

Separation of cell survival, growth, migration, and mesenchymal transdifferentiation effects of fibroblast secretome on tumor cells of head and neck squamous cell carcinoma

Fibroblasts play a central role in tumor invasion, recurrence, and metastasis in head and neck squamous cell carcinoma. The aim of this study was to investigate the influence of tumor cell self-produced factors and paracrine fibroblast–secreted factors in comparison to indirect co-culture on cancer cell survival, growth, migration, and epithelial–mesenchymal transition using the cell lines SCC-25 and human gingival fibroblasts. Thereby, we particularly focused on the participation of the fibroblast-secreted transforming growth factor beta-1.Tumor cell self-produced factors were sufficient to ensure tumor cell survival and basic cell growth, but fibroblast-secreted paracrine factors significantly increased cell proliferation, migration, and epithelial–mesenchymal transition–related phenotype changes in tumor cells. Transforming growth factor beta-1 generated individually migrating disseminating tumor cell groups or single cells separated from the tumor cell nest, which were characterized by reduced E-cadherin expression. At the same time, transforming growth factor beta-1 inhibited tumor cell proliferation under serum-starved conditions. Neutralizing transforming growth factor beta antibody reduced the cell migration support of fibroblast-conditioned medium. Transforming growth factor beta-1 as a single factor was sufficient for generation of disseminating tumor cells from epithelial tumor cell nests, while other fibroblast paracrine factors supported tumor nest outgrowth. Different fibroblast-released factors might support tumor cell proliferation and invasion, as two separate effects.

Evaluation of myofibroblasts in oral submucous fibrosis and oral squamous cell carcinoma: The pathogenesis and correlation

Background:

Oral submucous fibrosis (OSMF) is a chronic debilitating disease of the oral cavity having premalignant potential and unclear pathogenesis. Recently, myofibroblast has been postulated to play an important role in its pathogenesis and in the process of carcinogenesis. The purpose of this study was to evaluate and compare the presence of myofibroblasts in normal mucosa, different grades of OSMF, and oral squamous cell carcinoma (OSCC).

Materials and Methods:

The present in vitro cross-sectional descriptive study sample consisted of three groups, including 40 OSCCs, 40 OSMF, and 10 sections of normal oral epithelium taken as control group. Alpha-smooth muscle actin was used to identify myofibroblasts using immunohistochemical technique. P < 0.05 was taken as statistically significant.

Results:

The presence of myofibroblasts was significantly higher in OSMF cases when compared with normal epithelium specimens. The presence of myofibroblasts was significantly higher in OSCC compared to OSMF cases. A significant difference was not observed between the different grades of OSCC.

Conclusion:

These findings favor the possibility that OSMF actually represents an abnormal healing process in response irritation caused by areca nut. A significant increase in myofibroblasts in OSCC as compared to OSMF also highlights the possible role it may play in the malignant transformation of OSMF.