Relationship Between EGFR Expression in Oral Cancer Cell Lines and Cetuximab Antibody-dependent Cell-mediated Cytotoxicity

Mechanisms of hedgehog, calcium and retinoic acid signalling pathway inhibitors: Plausible modes of action along the MLL-EZH2-p53 axis in cellular growth control

Understanding the molecular mechanism(s) of small compounds in cellular growth control are essential for using those against the disease(s). Oral cancers exhibit a very high mortality rate due to higher metastatic potential. Aberrant EGFR, RAR, HH signalling, enhanced [Ca²⁺] and oxidative stress are some of the important characteristics of oral cancer. So, we target these for our study. Herein, we tested the effect of fendiline hydrochloride (FH) as an LTCC Ca²⁺-channel inhibitor, erismodegib (a SMO inhibitor of HH-signalling) and all-trans retinoic acid (RA) inducer of RAR signalling that causes cellular differentiation. OCT4 activating compound (OAC1) counters differentiation and induces stemness properties. Cytosine β-D arabinofuranoside (Cyto-BDA), a DNA replication inhibitor was used to reduce high proliferative capacity. Treatment of FaDu cells with OAC1, Cyto-BDA and FH increase G0/G1 population by 3%, 20% and 7% respectively, and lead to reduction of cyclin D1, CDK4/6 levels. Erismodegib arrests the cells in S-phase with reduced cyclin-E1&A1 levels, whereas RA-treatment causes G2/M phase arrest with reduced cyclin-B1. There was a decrease in the expression of EGFR and mesenchymal markers, Snail/Slug/Vim/Zeb/Twist, and increased E-cadherin expression in all the drug treatments, indicating a reduction in proliferative signal and EMT. Enhanced MLL2 (Mll4) and reduced EZH2 expression associated overexpression of p53 and p21 were traced out. We conclude that these drugs impact expression of epigenetic modifiers by modulating signalling pathways and the epigenetic modifiers then controls the expression of cell cycle control genes, including p53 and p21.

Simultaneous Detection of Two Extracellular Vesicle Subpopulations in Saliva Assisting Tumor T Staging of Oral Squamous Cell Carcinoma

Extracellular vesicles (EVs), acting as important mediators of intercellular communication, play an essential role in physiological processes, which have unique potential in the medical field. However, the heterogeneity of EVs limits their development for disease diagnosis and therapy, making the EV subpopulation analysis extremely valuable. In this article, a simple microfluidic approach was presented for the on-chip specific isolation and detection of two phenotypes of EVs (Annexin V⁺ EGFR⁺ EVs and Annexin V^- EGFR⁺ EVs) based on different biomolecule-modified magnetic nanospheres and a fluorescence labeling technique. Combined with the control of the magnetic field in the microzone and fluid flow, it was easy to form two separate functional regions in the chip to capture different EV subpopulations. This method was successfully applied to the tests of clinical saliva samples in 75 oral squamous cell carcinoma (OSCC) patients and 10 healthy people. The results showed that the total level of EGFR⁺ EVs was much higher in OSCC patients that in healthy people. Meantime, the ratio of Annexin V⁺ EGFR⁺ EVs to Annexin V^- EGFR⁺ EVs was found to be negatively correlated with tumor T stage of OSCC patients with a statistical difference, which suggested the ratio as a clinical index for monitoring the progression of OSCC in real time based on a noninvasive method. The approach provided a novel idea for evaluating the tumor T stage of OSCC and a powerful tool for clinical application.

EGFR, VEGF, and angiogenesis promote the development of lipoma in the oral cavity

This study aimed to detect, quantify and compare the immunohistochemical expression of EGFR and VEGF and microvessel count (MVC) in oral lipomas, and to correlate the findings with clinical and morphological characteristics of the cases studied. The sample consisted of 54 oral lipomas (33 classic and 21 non-classic) and 23 normal adipose tissue specimens. Cytoplasmic and/or nuclear immunohistochemical staining of EGFR and VEGF was analyzed. The angiogenic index was determined by MVC. Cells were counted using the Image J® software. The Statistical Package for the Social Sciences was used for data analysis, adopting a level of significance of 5% for all statistical tests. A statistically significant difference in EGFR immunoexpression (p=0.047), especially, between classic lipomas and normal adipose tissue. There was a significant difference in MVC between non-classic lipomas and normal adipose tissue (p=0.022). In non-classic lipomas, only VEGF immunoexpression showed a significant moderate positive correlation (r=0.607, p=0.01) with MVC. In classic lipomas, the number of EGFR-immunostained adipocytes was directly proportional to the number of VEGF-positive cells, demonstrating a significant moderate positive correlation (r=0.566, p=0.005). The results suggest that EGFR, VEGF, and angiogenesis participate in the development of oral lipomas but are not primarily involved in the growth of these tumors.

The Right Partner in Crime: Unlocking the Potential of the Anti-EGFR Antibody Cetuximab via Combination With Natural Killer Cell Chartering Immunotherapeutic Strategies

Cetuximab has an established role in the treatment of patients with recurrent/metastatic colorectal cancer and head and neck squamous cell cancer (HNSCC). However, the long-term effectiveness of cetuximab has been limited by the development of acquired resistance, leading to tumor relapse. By contrast, immunotherapies can elicit long-term tumor regression, but the overall response rates are much more limited. In addition to epidermal growth factor (EGFR) inhibition, cetuximab can activate natural killer (NK) cells to induce antibody-dependent cellular cytotoxicity (ADCC). In view of the above, there is an unmet need for the majority of patients that are treated with both monotherapy cetuximab and immunotherapy. Accumulated evidence from (pre-)clinical studies suggests that targeted therapies can have synergistic antitumor effects through combination with immunotherapy. However, further optimizations, aimed towards illuminating the multifaceted interplay, are required to avoid toxicity and to achieve better therapeutic effectiveness. The current review summarizes existing (pre-)clinical evidence to provide a rationale supporting the use of combined cetuximab and immunotherapy approaches in patients with different types of cancer.

Downregulation of miR-155-5p enhances the anti-tumor effect of cetuximab on triple-negative breast cancer cells via inducing cell apoptosis and pyroptosis

Cetuximab resistance is the main obstacle for the treatment of EGFR overexpression cancer, including triple-negative breast cancer (TNBC). MicroRNA (miRNA)-155-5p is upregulated in TNBC cells; thus, the present study explored whether the downregulation of miR-155-5p enhanced the anti-tumor effect of cetuximab in TNBC cells. MDA-MB-231 and MDA-MB-468 cells were infected with lentivirus-epidermal growth factor receptor (EGFR) for 72 h to obtain EGFR-overexpressed cell lines (MDA-MB-231 and MDA-MB-468). The inhibitory effects of cetuximab on the proliferation and migration of EGFR-overexpressed MDA-MB-468 cells were enhanced following transfection with the miR-155-5p antagomir, and miR-155-5p knockdown enhanced the pro-apoptotic effect of cetuximab on EGFR-overexpressed MDA-MB-468 cells. Further, the luciferase reporter assay revealed that gasdermin E (GSDME) was the direct binding target of miR-155-5p. The combination of cetuximab with the miR-155-5p antagomir promoted pyroptosis in EGFR-overexpressed MDA-MB-468 cells via the upregulation of GSDME-N and cleaved caspase-1. Results from the in vivo experiments confirmed that the downregulation of miR-155-5p enhanced the anti-tumor effect of cetuximab in an MDA-MB-468 xenograft model and on EGFR-overexpressed TNBC cells via inducing cell apoptosis and pyroptosis. Therefore, cetuximab combination with an miR-155-5p antagomir may be a novel therapeutic strategy for the treatment of TNBC.

Exosomal cargoes in OSCC: current findings and potential functions

Oral squamous cell carcinoma (OSCC) is the most prevalent malignancy in head and neck cancer, with high recurrence and mortality. Early diagnosis and efficient therapeutic strategies are vital for the treatment of OSCC patients. Exosomes can be isolated from a broad range of different cell types, implicating them as important factors in the regulation of human physiological and pathological processes. Due to their abundant cargo including proteins, lipids, and nucleic acids, exosomes have played a valuable diagnostic and therapeutic role across multiple diseases, including cancer. In this review, we summarize recent findings concerning the content within and participation of exosomes relating to OSCC and their roles in tumorigenesis, proliferation, migration, invasion, metastasis, and chemoresistance. We conclude this review by looking ahead to their potential utility in providing new methods for treating OSCC to inspire further research in this field.

Therapeutic applications of herbal/synthetic/bio-drug in oral cancer: An update

Oral cancer, as one of the most prevalent and invasive cancers that invade local tissue, can cause metastasis, and have high mortality. In 2018, around 355,000 worldwide oral cancers occurred and resulted in 177,000 deaths. Estimates for the year 2020 include about 53,260 new cases added to previous year's cases, and the estimated death toll from this cancer in 2020 is about 10,750 deaths more than previous years. Despite recent advances in cancer diagnosis and treatment, unfortunately, 50% of people with cancer cannot be cured. Of course, it should be remembered that the type of treatment used greatly influences patient recovery. There are not many choices when it comes to treating oral cancer. Research efforts focusing on the discovery and evolution of innovative therapeutic approaches for oral cancer are essential. Such traditional methods of treating this type of cancer like surgery and chemotherapy, have evolved dramatically during the past thirty to forty years, but they continue to cause panic among patients due to their side effects. Therefore, it is necessary to study and use drugs that are less risky for the patient as well as to provide solutions to reduce chemotherapy-induced adverse events that prevent many therapeutic risks. As mentioned above, this study examines low-risk therapies such as herbal remedies, biological drugs, and synthetic drugs in the hope that they will be useful to physicians, researchers, and scientists around the world.

Paclitaxel Potentiates the Anticancer Effect of Cetuximab by Enhancing Antibody-Dependent Cellular Cytotoxicity on Oral Squamous Cell Carcinoma Cells In Vitro

Administration of cetuximab (C-mab) in combination with paclitaxel (PTX) has been used for patients with head and neck squamous cell carcinoma (SCC) clinically. In this study, we attempted to clarify the molecular mechanisms of the enhancing anticancer effect of C-mab combined with PTX on oral SCC cells in vitro. We used two oral SCC cells (HSC4, OSC19) and A431 cells. PTX alone inhibited cell growth in all cells in a concentration-dependent manner. C-mab alone inhibited the growth of A431 and OSC19 cells at low concentrations, but inhibited the growth of HSC4 cells very weakly, even at high concentrations. A combined effect of the two drugs was moderate on A431 cells, but slight on HSC4 and OSC19 cells. A low concentration of PTX enhanced the antibody-dependent cellular cytotoxicity (ADCC) induced by C-mab in all of the cells tested. PTX slightly enhanced the anticancer effect of C-mab in this ADCC model on A431 and HSC4 cells, and markedly enhanced the anticancer effect of C-mab on OSC19 cells. These results indicated that PTX potentiated the anticancer effect of C-mab through enhancing the ADCC in oral SCC cells.

Cetuximab-induced natural killer cell cytotoxicity in head and neck squamous cell carcinoma cell lines: investigation of the role of cetuximab sensitivity and HPV status

Background

The epidermal growth factor receptor (EGFR) is overexpressed by 80–90% of squamous cell carcinoma of head and neck (HNSCC). In addition to inhibiting EGFR signal transduction, cetuximab, a monoclonal antibody targeting EGFR can also bind to fragment crystallisable domain of immunoglobulins G1 present on natural killer (NK), causing antibody-dependent cellular cytotoxicity (ADCC). However, presence of cetuximab resistance limits effective clinical management of HNSCC.

Methods

In this study, differences in induction of ADCC were investigated in a panel of ten HNSCC cell lines. Tumour cells were co-cultured with NK cells and monitored using the xCELLigence RTCA.

Results

While ADCC was not influenced by HPV status, hypoxia and cetuximab resistance did affect ADCC differentially. Intrinsic cetuximab-resistant cell lines showed an increased ADCC induction, whereas exposure to hypoxia reduced ADCC. Baseline EGFR expression was not correlated with ADCC. In contrast, EGFR internalisation following cetuximab treatment was positively correlated with ADCC.

Conclusion

These findings support the possibility that resistance against cetuximab can be overcome by NK cell-based immune reactions. As such, it provides an incentive to combine cetuximab with immunotherapeutic approaches, thereby possibly enhancing the anti-tumoural immune responses and achieving greater clinical effectiveness of EGFR-targeting agents.