Next-generation sequencing reveals remarkable genetic stability in primary and corresponding recurrent intestinal-type sinonasal adenocarcinoma.

BACKGROUND: Recurrent intestinal-type sinonasal adenocarcinoma (ITAC) can occur several years after primary treatment and with different histology. We aimed to clarify if such recurrences could be second primary tumors and to identify actionable mutations as targets for personalized treatment of recurrent ITAC. METHODS: Twelve pairs of primary and recurrent ITAC were histologically examined and analyzed by next-generation sequencing. RESULTS: Histological differences between primary and recurrent tumor pairs were observed in five cases. Frequent mutations included TP53, APC, TSC2, ATM, EPHA2, BRCA2, LRP1B, KRAS, and KMT2B. There was 86% concordance of somatic mutations between the tumor pairs, while four cases carried additional mutations in the recurrence. CONCLUSIONS: We found all cases to be clonal recurrences and not second primary tumors. Moreover, tumor pairs showed a remarkable genomic stability, suggesting that personalized treatment of a recurrence may be based on actionable molecular genetic targets observed in the primary tumor.

Sox2 and ßIII-Tubulin as Biomarkers of Drug Resistance in Poorly Differentiated Sinonasal Carcinomas.

Poorly differentiated sinonasal carcinomas (PDCs) are tumors that have a poor prognosis despite advances in classical treatment. Predictive and prognostic markers and new personalized treatments could improve the oncological outcomes of patients. In this study, we analyzed SOX2 and ßIII-tubulin as biomarkers that could have prognostic and therapeutic impacts on these tumors. The cohort included 57 cases of PDCs: 36 sinonasal undifferentiated carcinoma (SNUC) cases, 13 olfactory neuroblastoma (ONB) cases, and 8 sinonasal neuroendocrine carcinoma (SNEC) cases. Clinical follow-up data were available for 26 of these cases. Sox2 expression was detected using immunohistochemistry in 6 (75%) SNEC cases, 19 (53%) SNUC cases, and 6 (46%) ONB cases. The absence of Sox2 staining correlated with a higher rate of recurrence (p = 0.015), especially distant recurrence. The majority of cases showed ßIII-tubulin expression, with strong positivity in 85%, 75%, and 64% of SNEC, ONB, and SNUC cases, respectively. Tumors with stronger ßIII-tubulin expression demonstrated longer disease-free survival than those with no expression or low expression (p = 0.049). Sox2 and ßIII-tubulin expression is common in poorly differentiated sinonasal tumors and has prognostic and therapeutic utility.

Signaling Pathways mTOR and ERK as Therapeutic Targets in Sinonasal Intestinal-Type Adenocarcinoma.

Despite advances in surgery and radiotherapy, the overall prognosis of sinonasal intestinal-type adenocarcinoma (ITAC) is poor, and new treatment options are needed. Recent studies have indicated alterations in cellular signaling pathways that may serve as targets for modern inhibitors. Our aim was to evaluate the frequency of mTOR and ERK pathway upregulation in a retrospective series of 139 ITAC and to test the efficacy and mechanism of action of candidate targeted inhibitors in cell line ITAC-3. An immunohistochemical analysis on p-AKT, p-mTOR, p-S6, p-4E-BP1, and p-ERK indicated, respectively, a 68% and 57% mTOR and ERK pathway activation. In vitro studies using low doses of mTOR inhibitor everolimus and ERK inhibitor selumetinib showed significant growth inhibition as monotherapy and especially as combined therapy. This effect was accompanied by the downregulation of mTOR and ERK protein expression. Our data open a new and promising possibility for personalized treatment of ITAC patients.

A Novel External Auditory Canal Squamous Cell Carcinoma Cell Line Sensitive to CDK4/6 Inhibition.

OBJECTIVE: To characterize cell line CAE606 derived from a squamous cell carcinoma (SCC) of the external auditory canal (EAC) and to show its usefulness as a model for testing candidate therapeutic agents. STUDY DESIGN: Preclinical translational research. SETTING: Biomedical research institute. METHODS: The cell line was initiated from a moderately differentiated T2N0M0 EAC SCC. We studied its histologic and genetic features as well as growth and invasion parameters. Sensitivity to cell CDK4/6 cell cycle inhibitor palbociclib was analyzed. RESULTS: CAE606 cells expressed heavy molecular weight cytokeratin, p63, and vimentin. The population doubling time was 25.8 hours, and the cells showed fast collective cell migration in a wound-healing assay. Short tandem repeat analysis confirmed it to be derived from the primary tumor of the patient. Next-generation sequencing revealed alterations in cell cycle regulation genes, including inactivating mutations in CDKN2A and TP53 and high-level amplification of CCND1 and EGFR. CAE606 showed a strong decrease of phospo-Rb expression upon exposure to the CDK4/6 inhibitor palbociclib, causing significant growth inhibition with an IC50 of 0.46 µM. CONCLUSION: This is the first report of a stable EAC SCC cell line. Its genetic features make it a useful tool for preclinical testing of new therapeutic agents for EAC SCC, particularly those targeting cell cycle regulation in combination with radio- and chemotherapy or other specific signaling pathway inhibitors.

Characterization of a Preclinical In Vitro Model Derived from a SMARCA4-Mutated Sinonasal Teratocarcinosarcoma.

Sinonasal teratocarcinosarcoma (TCS) is a rare tumor that displays a variable histology with admixtures of epithelial, mesenchymal, neuroendocrine and germ cell elements. Facing a very poor prognosis, patients with TCS are in need of new options for treatment. Recently identified recurrent mutations in SMARCA4 may serve as target for modern therapies with EZH1/2 and CDK4/6 inhibitors. Here, we present the first in vitro cell line TCS627, established from a previously untreated primary TCS originating in the ethmoid sinus with invasion into the brain. The cultured cells expressed immunohistochemical markers, indicating differentiation of epithelial, neuroepithelial, sarcomatous and teratomatous components. Whole-exome sequencing revealed 99 somatic mutations including SMARCA4, ARID2, TET2, CDKN2A, WNT7A, NOTCH3 and STAG2, all present both in the primary tumor and in the cell line. Focusing on mutated SMARCA4 as the therapeutic target, growth inhibition assays showed a strong response to the CDK4/6 inhibitor palbociclib, but much less to the EZH1/2 inhibitor valemetostat. In conclusion, cell line TCS627 carries both histologic and genetic features characteristic of TCS and is a valuable model for both basic research and preclinical testing of new therapeutic options for treatment of TCS patients.

Biomarkers for Immunotherapy in Poorly Differentiated Sinonasal Tumors.

The sinonasal cavities harbor a wide variety of rare cancer types. Histopathological classification can be challenging, especially for poorly differentiated tumors. Despite advances in surgery and radio-chemotherapy, the 5-year survival rate is still very low. Thus, there is an unmet clinical need for new therapeutic options. We retrospectively evaluated poorly differentiated tumors of 9 different histological subtypes from 69 patients who had received conventional treatments for the presence of CD8+ tumor-infiltrating lymphocytes (TILs), as well as the expression of PD-L1 and microsatellite instability (MSI) markers MLH1, MSH2, MSH6 and PMS2, as biomarkers for immunotherapy. CD8+ TILs were present in 23/69 (33%) cases, PD-L1 expression was observed in 23/69 (33%), and markers for MSI positivity in 5/69 (7%) cases. CD8+ TILs correlated with PD-L1 positivity, while both were mutually exclusive with MSI markers. None of the biomarkers were associated with clinical features as age, gender or tumor stage. Cases with CD8+ TILs and PD-L1 positivity showed a tendency toward worse disease-specific survival. Immune checkpoint inhibitors are emerging as new options for treatment of many tumor types. Our results indicate that also a substantial subset of patients with poorly differentiated sinonasal tumors may be a candidate to be treated with this promising new therapy.

Dysregulation of Translation Factors EIF2S1, EIF5A and EIF6 in Intestinal-Type Adenocarcinoma (ITAC).

Intestinal-type adenocarcinoma (ITAC) is a rare cancer of the nasal cavity and paranasal sinuses that occurs sporadically or secondary to exposure to occupational hazards, such as wood dust and leather. Eukaryotic translation initiation factors have been described as promising targets for novel cancer treatments in many cancers, but hardly anything is known about these factors in ITAC. Here we performed in silico analyses, evaluated the protein levels of EIF2S1, EIF5A and EIF6 in tumour samples and non-neoplastic tissue controls obtained from 145 patients, and correlated these results with clinical outcome data, including tumour site, stage, adjuvant radiotherapy and survival. In silico analyses revealed significant upregulation of the translation factors EIF6 (ITGB4BP), EIF5, EIF2S1 and EIF2S2 (p < 0.05) with a higher arithmetic mean expression in ITAC compared to non-neoplastic tissue (NNT). Immunohistochemical analyses using antibodies against EIF2S1 and EIF6 confirmed a significantly different expression at the protein level (p < 0.05). In conclusion, this work identifies the eukaryotic translation initiation factors EIF2S1 and EIF6 to be significantly upregulated in ITAC. As these factors have been described as promising therapeutic targets in other cancers, this work identifies candidate therapeutic targets in this rare but often deadly cancer.

Physical exercise shapes the mouse brain epigenome.

OBJECTIVE: To analyze the genome-wide epigenomic and transcriptomic changes induced by long term resistance or endurance training in the hippocampus of wild-type mice. METHODS: We performed whole-genome bisulfite sequencing (WGBS) and RNA sequencing (RNA-seq) of mice hippocampus after 4 weeks of specific training. In addition, we used a novel object recognition test before and after the intervention to determine whether the exercise led to an improvement in cognitive function. RESULTS: Although the majority of DNA methylation changes identified in this study were training-model specific, most were associated with hypomethylation and were enriched in similar histone marks, chromatin states, and transcription factor biding sites. It is worth highlighting the significant association found between the loss of DNA methylation in Tet1 binding sites and gene expression changes, indicating the importance of these epigenomic changes in transcriptional regulation. However, endurance and resistance training activate different gene pathways, those being associated with neuroplasticity in the case of endurance exercise, and interferon response pathways in the case of resistance exercise, which also appears to be associated with improved learning and memory functions. CONCLUSIONS: Our results help both understand the molecular mechanisms by which different exercise models exert beneficial effects for brain health and provide new potential therapeutic targets for future research.

ATG4D is the main ATG8 delipidating enzyme in mammalian cells and protects against cerebellar neurodegeneration.

Despite the great advances in autophagy research in the last years, the specific functions of the four mammalian Atg4 proteases (ATG4A-D) remain unclear. In yeast, Atg4 mediates both Atg8 proteolytic activation, and its delipidation. However, it is not clear how these two roles are distributed along the members of the ATG4 family of proteases. We show that these two functions are preferentially carried out by distinct ATG4 proteases, being ATG4D the main delipidating enzyme. In mammalian cells, ATG4D loss results in accumulation of membrane-bound forms of mATG8s, increased cellular autophagosome number and reduced autophagosome average size. In mice, ATG4D loss leads to cerebellar neurodegeneration and impaired motor coordination caused by alterations in trafficking/clustering of GABAA receptors. We also show that human gene variants of ATG4D associated with neurodegeneration are not able to fully restore ATG4D deficiency, highlighting the neuroprotective role of ATG4D in mammals.

Autophagy is required for performance adaptive response to resistance training and exercise-induced adult neurogenesis.

Endurance training promotes exercise-induced adaptations in brain, like hippocampal adult neurogenesis and autophagy induction. However, resistance training effect on the autophagy response in the brain has not been much explored. Questions such as whether partial systemic autophagy or the length of training intervention affect this response deserve further attention. Therefore, 8-week-old male wild-type (Wt; n = 36) and systemic autophagy-deficient (atg4b-/- , KO; n = 36) mice were randomly distributed in three training groups, resistance (R), endurance (E), and control (non-trained), and in two training periods, 2 or 14 weeks. R and E maximal tests were evaluated before and after the training period. Forty-eight hours after the end of training program, cerebral cortex, striatum, hippocampus, and cerebellum were extracted for the analysis of autophagy proteins (LC3B-I, LC3B-II, and p62). Additionally, hippocampal adult neurogenesis was determined by doublecortin-positive cells count (DCX+) in brain sections. Our results show that, in contrast to Wt, KO were unable to improve R after both trainings. Autophagy levels in brain areas may be modified by E training only in cerebral cortex of Wt trained for 14 weeks, and in KO trained for 2 weeks. DCX + in Wt increased in R and E after both periods of training, with R for 14 weeks more effective than E. Interestingly, no changes in DCX + were observed in KO after 2 weeks, being even undetectable after 14 weeks of intervention. Thus, autophagy is crucial for R performance and for exercise-induced adult neurogenesis.