Biology and patterns of response to EGFR-inhibition in squamous cell cancers of the lung and head & neck

Endoscopic Applications of Near-Infrared Photoimmunotherapy (NIR-PIT) in Cancers of the Digestive and Respiratory Tracts

Near-infrared photoimmunotherapy (NIR-PIT) is a newly developed and promising therapy that specifically destroys target cells by irradiating antibody-photo-absorber conjugates (APCs) with NIR light. APCs bind to target molecules on the cell surface, and when exposed to NIR light, cause disruption of the cell membrane due to the ligand release reaction and dye aggregation. This leads to rapid cell swelling, blebbing, and rupture, which leads to immunogenic cell death (ICD). ICD activates host antitumor immunity, which assists in killing still viable cancer cells in the treated lesion but is also capable of producing responses in untreated lesions. In September 2020, an APC and laser system were conditionally approved for clinical use in unresectable advanced head and neck cancer in Japan, and are now routine in appropriate patients. However, most tumors have been relatively accessible in the oral cavity or neck. Endoscopes offer the opportunity to deliver light deeper within hollow organs of the body. In recent years, the application of endoscopic therapy as an alternative to surgery for the treatment of cancer has expanded, providing significant benefits to inoperable patients. In this review, we will discuss the potential applications of endoscopic NIR-PIT, especially in thoracic and gastrointestinal cancers.

Potential of Farnesyl Transferase Inhibitors in Combination Regimens in Squamous Cell Carcinomas

Current therapies for recurrent and metastatic SCC are associated with poor outcomes, and options for later lines of treatment are limited. Insights into potential therapeutic targets, as well as mechanisms of resistance to available therapies, have begun to be elucidated, creating the basis for exploration of combination approaches to drive better patient outcomes. Tipifarnib, a farnesyl transferase inhibitor (FTI), is a small molecule drug that has demonstrated encouraging clinical activity in a genetically-defined subset of head and neck squamous cell carcinoma (HNSCC)-specifically, tumors that express a mutation in the HRAS protooncogene. More recently, bioinformatic analyses and results from patient-derived xenograft modeling indicate that HRAS pathway dependency may extend to a broader subpopulation of SCCs beyond HRAS mutants in the context of combination with agents such as cisplatin, cetuximab, or alpelisib. In addition, tipifarnib can also inactivate additional farnesylated proteins implicated in resistance to approved therapies, including immunotherapies, through a variety of distinct mechanisms, suggesting that tipifarnib could serve as an anchor for combination regimens in SCCs and other tumor types.

Current Aspects and Future Considerations of EGFR Inhibition in Locally Advanced and Recurrent Metastatic Squamous Cell Carcinoma of the Head and Neck

Simple Summary

Squamous cell carcinoma of the head and neck (SCCHN) is a debilitating disease that affects hundreds of thousands of individuals worldwide and has a high mortality rate. Mainstay treatment largely consists of surgery, radiation, and chemotherapy which has been met with significant morbidity. The epidermal growth factor receptor is one that which plays a major role in cell signaling and has been extensively studied in locally advanced (LA) and recurrent metastatic (RM) SCCHN. This review paper details the major roles of the epidermal growth factor receptor (EGFR), previous and current EGFR inhibition therapeutics, resistance mechanisms, and the possible integration of immunotherapy and EGFR inhibition in this disease process.

Abstract

Recurrent metastatic (RM) and locally advanced (LA) squamous cell carcinoma of the head and neck (SCCHN) are devasting disease states with limited therapeutic options and poor overall survival. Targeting the epidermal growth factor receptor (EGFR) is one area that has helped improve outcomes in this disease. Anti-EGFR based therapies have been shown to improve overall survival and mitigate the significant toxicities incurred from standard radiation, chemotherapy, and/or surgical options. Cetuximab, the most well-studied anti-EGFR monoclonal antibody, has demonstrated a positive impact on outcomes for RM and LA SCCHN. However, the development of early resistance to cetuximab highlights the need for a wider arsenal of therapy for RM and LA diseases. The use of immune checkpoint inhibitors has recently transformed the treatment of recurrent SCCHN. Drugs such as pembrolizumab and nivolumab have demonstrated success in recent clinical trials and have been approved for the treatment of advanced disease. Given the positive results of both EGFR targeted agents and immune checkpoint inhibitors, ongoing trials are studying their synergistic effects.

Biological Determinants of Chemo-Radiotherapy Response in HPV-Negative Head and Neck Cancer: A Multicentric External Validation

Purpose: Tumor markers that are related to hypoxia, proliferation, DNA damage repair and stem cell-ness, have a prognostic value in advanced stage HNSCC patients when assessed individually. Here we aimed to evaluate and validate this in a multifactorial context and assess interrelation and the combined role of these biological factors in determining chemo-radiotherapy response in HPV-negative advanced HNSCC. Methods: RNA sequencing data of pre-treatment biopsy material from 197 HPV-negative advanced stage HNSCC patients treated with definitive chemoradiotherapy was analyzed. Biological parameter scores were assigned to patient samples using previously generated and described gene expression signatures. Locoregional control rates were used to assess the role of these biological parameters in radiation response and compared to distant metastasis data. Biological factors were ranked according to their clinical impact using bootstrapping methods and multivariate Cox regression analyses that included clinical variables. Multivariate Cox regression analyses comprising all biological variables were used to define their relative role among all factors when combined. Results: Only few biomarker scores correlate with each other, underscoring their independence. The different biological factors do not correlate or cluster, except for the two stem cell markers CD44 and SLC3A2 (r = 0.4, p < 0.001) and acute hypoxia prediction scores which correlated with T-cell infiltration score, CD8⁺ T cell abundance and proliferation scores (r = 0.52, 0.56, and 0.6, respectively with p < 0.001). Locoregional control association analyses revealed that chronic (Hazard Ratio (HR) = 3.9) and acute hypoxia (HR = 1.9), followed by stem cell-ness (CD44/SLC3A2; HR = 2.2/2.3), were the strongest and most robust determinants of radiation response. Furthermore, multivariable analysis, considering other biological and clinical factors, reveal a significant role for EGFR expression (HR = 2.9, p < 0.05) and T-cell infiltration (CD8⁺T-cells: HR = 2.2, p < 0.05; CD8⁺T-cells/Treg: HR = 2.6, p < 0.01) signatures in locoregional control of chemoradiotherapy-treated HNSCC. Conclusion: Tumor acute and chronic hypoxia, stem cell-ness, and CD8⁺ T-cell parameters are relevant and largely independent biological factors that together contribute to locoregional control. The combined analyses illustrate the additive value of multifactorial analyses and support a role for EGFR expression analysis and immune cell markers in addition to previously validated biomarkers. This external validation underscores the relevance of biological factors in determining chemoradiotherapy outcome in HNSCC.

Patient-Derived Xenografts for Prognostication and Personalized Treatment for Head and Neck Squamous Cell Carcinoma

Overall survival remains very poor for patients diagnosed as having head and neck squamous cell carcinoma (HNSCC). Identification of additional biomarkers and novel therapeutic strategies are important for improving patient outcomes. Patient-derived xenografts (PDXs), generated by implanting fresh tumor tissue directly from patients into immunodeficient mice, recapitulate many of the features of their corresponding clinical cancers, including histopathological and molecular profiles. Using a large collection of PDX models of HNSCC, we demonstrate that rapid engraftment into immunocompromised mice is highly prognostic and show that genomic deregulation of the G1/S checkpoint pathway correlates with engraftment. Furthermore, CCND1 and CDKN2A genomic alterations are predictive of response to the CDK4and CDK6 inhibitor abemaciclib. Overall, our study supports the pursuit of CDK4 and CDK6 inhibitors as a therapeutic strategy for a substantial proportion of HNSCC patients and demonstrates the potential of using PDX models to identify targeted therapies that will benefit patients who have the poorest outcomes.

Novel genetic alterations and their impact on target therapy response in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is highly variable by tumor site, histologic type, molecular characteristics, and clinical outcome. During recent years, emerging targeted therapies have been focused on driver genes. HNSCC involves several genetic alterations, such as co-occurrence, multiple feedback loops, and cross-talk communications. These different kinds of genetic alterations interact with each other and mediate targeted therapy response. In the current review, it is emphasized that future treatment strategy in HNSCC will not solely be based on "synthetic lethality" approaches directed against overactivated genes. More importantly, biologic, genetic, and epigenetic alterations of HNSCC will be taken into consideration to guide the therapy. The emerging genetic alterations in HNSCC and its effect on targeted therapy response are discussed in detail. Hopefully, novel combination regimens for the treatment of HNSCC can be developed.

The functional verification of EGFR-CAR T-cells targeted to hypopharyngeal squamous cell carcinoma

BACKGROUND

The aim of this study was to validate the antitumor function of EGFR-chimeric antigen T-cells (CART) targeted to FaDu cells, a hypopharyngeal squamous cell carcinoma cell line, and to provide a preclinical basis for the application of CART cell technology in hypopharyngeal squamous cell carcinoma.

METHODS

Detection of cytokine secretions of EGFR-CAR T and CART-controls in the presence of target cells and nontarget cells as an indicator of CART cell activation. Detection of the cytotoxic effects of EGFR-CAR T on specific tumors in the presence of target cells was evaluated by LDH release and CART cell proliferation.

RESULTS

The results showed that cytokine secretion increased significantly after EGFR-CAR T-cells were incubated with target cells, and EGFR-CAR T-cells has higher cytotoxic effect on target cells than the CART-control group. The target cell lysis rate was 52.66%. The proliferation of EGFR-CAR T-cells in the presence of target cells was not distinctly observed.

CONCLUSION

In this study, we validated the antitumor function of EGFR-CAR T-cells targeted to the FaDu cell line and provided the foundation for application of the CART technique in the treatment of hypopharyngeal carcinoma.

Invasion-Related Factors as Potential Diagnostic and Therapeutic Targets in Oral Squamous Cell Carcinoma-A Review

It is well recognized that the presence of cervical lymph node metastasis is the most important prognostic factor in oral squamous cell carcinoma (OSCC). In solid epithelial cancer, the first step during the process of metastasis is the invasion of cancer cells into the underlying stroma, breaching the basement membrane (BM)—the natural barrier between epithelium and the underlying extracellular matrix (ECM). The ability to invade and metastasize is a key hallmark of cancer progression, and the most complicated and least understood. These topics continue to be very active fields of cancer research. A number of processes, factors, and signaling pathways are involved in regulating invasion and metastasis. However, appropriate clinical trials for anti-cancer drugs targeting the invasion of OSCC are incomplete. In this review, we summarize the recent progress on invasion-related factors and emerging molecular determinants which can be used as potential for diagnostic and therapeutic targets in OSCC.

Aldolase A promotes proliferation and G1/S transition via the EGFR/MAPK pathway in non-small cell lung cancer

BACKGROUND

Our previous study demonstrated that aldolase A (ALDOA) is overexpressed in clinical human lung squamous cell carcinoma and that ALDOA promotes epithelial-mesenchymal transition and tumorigenesis. The present study aimed to explore the function of ALDOA in the modulation of non-small cell lung cancer (NSCLC) proliferation and cell cycle progression and the potential mechanism.

METHODS

ALDOA was knocked down by short hairpin RNA in H520 and H1299 cells. ALDOA was overexpressed with vectors carrying the full-length ALDOA sequence in H1299 and H157 cells. The proliferation capacities were assessed with immunohistochemical staining, Cell Counting Kit-8 and colony formation assays. The cell cycle distribution was examined by flow cytometry, and molecular alterations were determined by western blotting. Cell synchronization was induced with nocodazole. The stability of cyclin D1 mRNA was tested. The pyruvate kinase M2 and ALDOA protein distributions were examined. Aerobic glycolysis was evaluated with Cell Titer-Glo assay, glucose colorimetric assay and lactate colorimetric assay.

RESULTS

ALDOA knockdown inhibited the proliferation and G₁/S transition in H520 cells. Conversely, ALDOA overexpression promoted the proliferation and G₁/S transition in H157 cells. The cell cycle synchronization assay showed that ALDOA expression increased in the G₁ phase and G₁/S transition. Furthermore, ALDOA knockdown reduced cyclin D1 expression by regulating epidermal growth factor receptor/mitogen-activated protein kinase (EGFR/MAPK) pathway. Similar results were found in H1299 and H157 cells. The inhibition of mitogen-activated protein kinase kinase 1/2 prompted the nuclear distribution of ALDOA. Additionally, ALDOA knockdown reduced nuclear distribution of PKM2, the extracellular lactate and intracellular adenosine triphosphate concentrations and elevated the extracellular glucose concentration.

CONCLUSIONS

ALDOA contributed to activation of the EGFR/MAPK pathway, thus promoting cyclin D1 expression and enhancing proliferation and G₁/S transition in NSCLC. Additionally, ALDOA facilitated NSCLC aerobic glycolysis.

Effects of Cetuximab and Erlotinib on the behaviour of cancer stem cells in head and neck squamous cell carcinoma

The therapeutic responses of many solid tumours to chemo- and radio-therapies are far from fully effective but therapies targeting malignancy-related cellular changes show promise for further control. In head and neck squamous cell carcinoma, the epidermal growth factor receptor (EGFR) is commonly overexpressed and investigation of agents that block this receptor indicate a limited response when used alone but an ability to enhance the actions of other drugs. The hierarchical stem cell patterns present in tumours generate cellular heterogeneity and this is further complicated by cancer stem cells (CSC) shifting between epithelial (Epi-CSC) and mesenchymal (EMT-CSC) states. To clarify how such heterogeneity influences responses to EGFR blocking, we examined the effects of Cetuximab and Erlotinib on the cell sub-populations in HNSCC cell lines. These agents reduced cell proliferation for all subpopulations but induced little cell death. They did however induce large shifts of cells between the EMT-CSC, Epi-CSC and differentiating cell compartments. Loss of EMT-CSCs reduced cell motility and is expected to reduce invasion and metastasis. EGFR blocking also induced shifts of Epi-CSCs into the differentiating cell compartment which typically has greater sensitivity to chemo/radiation, an effect expected to enhance the overall response of tumour cell populations to adjunctive therapies.

Characterization of 7A7, an anti-mouse EGFR monoclonal antibody proposed to be the mouse equivalent of cetuximab

The Epidermal Growth Factor Receptor (EGFR) is selectively expressed on the surface of numerous tumours, such as non-small cell lung, ovarian, colorectal and head and neck carcinomas. EGFR has therefore become a target for cancer therapy. Cetuximab is a chimeric human/mouse monoclonal antibody (mAb) that binds to EGFR, where it both inhibits signaling and induces cell death by antibody-dependent cell mediated cytotoxicity (ADCC). Cetuximab has been approved for clinical use in patients with head and neck squamous cell carcinoma (HNSCC) and colorectal cancer. However, only 15-20% patients benefit from this drug, thus new strategies to improve cetuximab efficiency are required. We aimed to develop a reliable and easy preclinical mouse model to evaluate the efficacy of EGFR-targeted antibodies and examine the immune mechanisms involved in tumour regression. We selected an anti-mouse EGFR mAb, 7A7, which has been reported to be "mouse cetuximab" and to exhibit similar properties to its human counterpart. Unfortunately, we were unable to reproduce previous results obtained with the 7A7 mAb. In our hands, 7A7 failed to recognize mouse EGFR, both in native and reducing conditions. Moreover, in vivo administration of 7A7 in an EGFR-expressing HPV38 tumour model did not have any impact on tumour regression or animal survival. We conclude that 7A7 does not recognize mouse EGFR and therefore cannot be used as the mouse equivalent of cetuximab use in humans. As a number of groups have spent effort and resources with similar issues we feel that publication is a responsible approach.

Heterogeneous distribution of alectinib in neuroblastoma xenografts revealed by matrix-assisted laser desorption ionization mass spectrometry imaging: a pilot study

BACKGROUND AND PURPOSE

The penetration of the anaplastic lymphoma kinase (ALK) inhibitor alectinib in neuroblastomas and the relationship between alectinib and ALK expression are unknown. The aim of this study was to perform a quantitative investigation of the inter- and intra-tumoural distribution of alectinib in different neuroblastoma xenograft models using matrix-assisted laser desorption ionization MS imaging (MALDI-MSI).

EXPERIMENTAL APPROACH

The distribution of alectinib in NB1 (ALK amplification) and SK-N-FI (ALK wild-type) xenograft tissues was analysed using MALDI-MSI. The abundance of alectinib in tumours and intra-tumoural areas was quantified using ion signal intensities from MALDI-MSI after normalization by correlation with LC-MS/MS.

KEY RESULTS

The distribution of alectinib was heterogeneous in neuroblastomas. The penetration of alectinib was not significantly different between ALK amplification and ALK wide-type tissues using both LC-MS/MS concentrations and MSI intensities. Normalization with an internal standard increased the quantitative property of MSI by adjusting for the ion suppression effect. The distribution of alectinib in different intra-tumoural areas can alternatively be quantified from MS images by correlation with LC-MS/MS.

CONCLUSION AND IMPLICATIONS

The penetration of alectinib into tumour tissues may not be homogenous or influenced by ALK expression in the early period after single-dose administration. MALDI-MSI may prove to be a valuable pharmaceutical method for elucidating the mechanism of action of drugs by clarifying their microscopic distribution in heterogeneous tissues.