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Treatment with analogues of the SERCA-inhibitor Thapsigargin is a promising new approach for a wide variety of cancer entities. However, our previous studies on various tumor cells suggested resistance of SEC62 over-expressing tumors to this treatment. Therefore, we proposed the novel concept that e.g. lung-, prostate-, and thyroid-cancer patients should be tested for SEC62 over-expression, and developed a novel therapeutic strategy for a combinatorial treatment of SEC62 over-expressing tumors. The latter was based on the observations that treatment of SEC62 over-expressing tumor cells with SEC62-targeting siRNAs showed less resistance to Thapsigargin as well as a reduction in migratory potential and that the siRNA effects can be mimicked by the Calmodulin antagonist Trifluoperazine. Therefore, the combinatorial treatment of SEC62 over-expressing tumors was proposed to involve Thapsigargin and Trifluoperazine. Here, we addressed the impact of Thapsigargin and Trifluoperazine in separate and combined treatments of heterotopic tumors, induced by inoculation of human hypopharyngeal squamous cell carcinoma (FaDu)-cells into the mouse flank. Seeding of the tumor cells and/or their growth rate were significantly reduced by all three treatments, suggesting Trifluoperazine is a small molecule to be considered for future therapeutic strategies for patients, suffering from Sec62-overproducing tumors.

Various cancer types including head and neck squamous cell carcinomas (HNSCC) show a frequent amplification of chromosomal region 3q26 that encodes, among others, for the SEC62 gene. Located in the ER membrane, this translocation protein is known to play a critical role as a potential driver oncogene in cancer development. High SEC62 expression levels were observed in various cancer entities and were associated with a poor outcome and increased metastatic burden. Because of its intracellular localization the SEC62 protein is poorly accessible for therapeutic antibodies, therefore a functional SEC62 knockdown represents the most promising mechanism of a potential antineoplastic targeted therapy. By stimulating the Ca2+ efflux from the ER lumen and thereby increasing cellular stress levels, a functional inhibition of SEC62 bears the potential to limit tumor growth and metastasis formation. In this study, two potential anti-metastatic and -proliferative agents that counteract SEC62 function were investigated in functional in vitro assays by utilizing an immortalized human hypopharyngeal cancer cell line as well as a newly established orthotopic murine in vivo model. Additionally, a CRISPR/Cas9 based SEC62 knockout HNSCC cell line was generated and functionally characterized for its relevance in HNSCC cell proliferation and migration as well as sensitivity to SEC62 targeted therapy in vitro. [ABSTRACT FROM AUTHOR]

Atypical fibroxanthoma (AFX) is a rare mesenchymal tumor with predominance in older male patients located mainly in chronically UV-exposed skin. Differentiation from clinically more aggressive pleomorphic dermal sarcoma (PDS) is still under debate and immunohistochemical markers are not available yet. An immunohistochemical study, including 41 cases of AFX was conducted to investigate the expression of 3q encoded oncogene SEC62 in AFX and determine the associations with histomorphologic, clinical and viral parameters. Our cohort displayed a mean of 79.9 years at the onset of the disease. In total, 90.2% (37/41) AFXs were located in the head and neck area, whereas, four were located at the extremities (9.7%). Tumor diameter ranged between 0.06 and 40 cm2 with a mean of 5.7 cm2. SEC62 expression was markedly increased in lesional tissue compared with the adjacent healthy squamous epithelium. We found significantly higher expression of SEC62 in cases of AFX with tumor necrosis. Tendency of higher Sec62-IRS-scores were found for tumors with higher Clark levels and a tumor size >5 cm2. Sec62 is involved in endoplasmic reticulum stress tolerance and cell migration, and has been identified as a novel prognostic marker for non-small cell lung cancer as well as head and neck squamous cell carcinoma. For the first time, to the best of our knowledge, we suggest a role of 3q oncogene SEC62 in AFX and discuss a potential prognostic relevance in cases of disputable AFX with unfavorable histomorphologic features and may initiate a discussion on Sec62 serving as discriminating marker between AFX and PDS. [ABSTRACT FROM AUTHOR]

Summary: The peroxisomal sterol carrier protein 2 (Scp2) of the biotrophic maize pathogen Ustilago maydis was detected in apoplastic fluid, suggesting that it might function as a secreted effector protein. Here we analyze the role of the scp2 gene during plant colonization. We used reverse genetics approaches to delete the scp2 gene, determined stress sensitivity and fatty acid utilization of mutants, demonstrated secretion of Scp2, used quantitative reverse transcription polymerase chain reaction for expression analysis and expressed GFP‐Scp2 fusion proteins for protein localization. scp2 mutants were strongly attenuated in virulence and this defect manifested itself during penetration. Scp2 localized to peroxisomes and peroxisomal targeting was necessary for its virulence function. Deletion of scp2 in U. maydis interfered neither with growth nor with peroxisomal β‐oxidation. Conventionally secreted Scp2 protein could not rescue the virulence defect. scp2 mutants displayed an altered localization of peroxisomes. Our results show a virulence function for Scp2 during penetration that is probably carried out by Scp2 in peroxisomes. We speculate that Scp2 affects the lipid composition of membranes and in this way ensures the even cellular distribution of peroxisomes. [ABSTRACT FROM AUTHOR]

BACKGROUND High-risk human papillomavirus (HPV) infection has been identified as a relevant risk for the development of head and neck squamous cell carcinomas (HNSCCs). As HPV status has also gained a role as a prognostic and predictive biomarker for this entity, there is a growing demand for valid HPV testing in HNSCC patients METHODS Liquid-based cytological smears from 45 HNSCC and 20 control patients were collected and used for simultaneous immunocytochemical p16INK4a/Ki67 staining using a CINtec PLUS kit after the presence of tumor cells was verified in a Papanicolaou-stained slide. The same cytological suspension was used for the detection of HPV DNA by specific polymerase chain reaction (PCR). RESULTS Tumor cells were detected in the swab material of 44 HNSCC patients corresponding to a sensitivity of 98% (44 of 45). PCR analysis revealed the presence of HPV DNA in the cytological suspension of 13 patients (13 of 65, 20%) with simultaneous p16INK4a/Ki67 expression by the tumor cells in 11 of these HPV DNA-positive samples (11 of 13, 85%) - a staining pattern that is strongly associated with a carcinogenic HPV infection. CONCLUSIONS A simultaneous immunocytochemical detection of p16INK4a and Ki67 can reliably be performed on liquid-based cytological smears from HNSCC patients using a CINtec PLUS kit. In addition, the same cytological material can be used for the detection of HPV DNA by specific PCR. The combined results of both techniques enable better discrimination between latent and carcinogenic HPV infections as well as HPV-negative cases and thus can provide information on the prognosis of HNSCC patients and facilitate therapeutic decisions. Cancer (Cancer Cytopathol) 2015;123:219-229. © 2014 American Cancer Society. [ABSTRACT FROM AUTHOR]

Various cancer types including head and neck squamous cell carcinomas (HNSCC) show a frequent amplification of chromosomal region 3q26 that encodes, among others, for the SEC62 gene. Located in the ER membrane, this translocation protein is known to play a critical role as a potential driver oncogene in cancer development. High SEC62 expression levels were observed in various cancer entities and were associated with a poor outcome and increased metastatic burden. Because of its intracellular localization the SEC62 protein is poorly accessible for therapeutic antibodies, therefore a functional SEC62 knockdown represents the most promising mechanism of a potential antineoplastic targeted therapy. By stimulating the Ca 2+ efflux from the ER lumen and thereby increasing cellular stress levels, a functional inhibition of SEC62 bears the potential to limit tumor growth and metastasis formation. In this study, two potential anti-metastatic and -proliferative agents that counteract SEC62 function were investigated in functional in vitro assays by utilizing an immortalized human hypopharyngeal cancer cell line as well as a newly established orthotopic murine in vivo model. Additionally, a CRISPR/Cas9 based SEC62 knockout HNSCC cell line was generated and functionally characterized for its relevance in HNSCC cell proliferation and migration as well as sensitivity to SEC62 targeted therapy in vitro ., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Körner, Pick, Bochen, Wemmert, Körbel, Menger, Cavalié, Kühn, Schick and Linxweiler.)

Chromosome 3q26 amplification represents a frequent alteration in head and neck squamous cell carcinomas (HNSCCs). Overexpression of 3q26 encoded genes SEC62 and SOX2 was detected in various cancers, including HNSCCs, indicating their potential function as oncogenes. In our study, we elucidated the function of SEC62 and SOX2 in HNSCC patients, with a main focus on their effect on lymphatic metastasis and patient survival. We analyzed SEC62 and SOX2 expression in tissue specimens from 65 HNSCC patients and 29 patients with cervical cancer of unknown primary (CUP); a higher SEC62 and lower SOX2 expression was observed in the lymph node metastases from HNSCC patients compared with the respective primary tumor. Lymph node metastases from CUP patients showed higher SEC62 and lower SOX2 expression compared with lymph node metastases from HNSCC patients. When proceeding from the N1 to the N3 stage, SEC62 expression in the lymph node metastases showed an increase and SOX2 expression showed a decrease. Moreover, both genes showed a highly significant relevance as prognostic biomarkers, with the worst prognosis for patients with high SEC62 and low SOX2 expression levels. In functional analyses, knockdown of SEC62 resulted in an inhibition of HNSCC cell migration while, conversely, SEC62 and SOX2 overexpression stimulated cell migration. Taken together, our study showed that the expression of the 3q oncogenes SEC62 and SOX2 affects lymphatic metastasis and cell migration in HNSCC and CUP patients and has a high prognostic relevance in these diseases.

Background: High-risk human papillomavirus (HPV) infection has been identified as a relevant risk for the development of head and neck squamous cell carcinomas (HNSCCs). As HPV status has also gained a role as a prognostic and predictive biomarker for this entity, there is a growing demand for valid HPV testing in HNSCC patients, Methods: Liquid-based cytological smears from 45 HNSCC and 20 control patients were collected and used for simultaneous immunocytochemical p16(INK4a) /Ki67 staining using a CINtec PLUS kit after the presence of tumor cells was verified in a Papanicolaou-stained slide. The same cytological suspension was used for the detection of HPV DNA by specific polymerase chain reaction (PCR)., Results: Tumor cells were detected in the swab material of 44 HNSCC patients corresponding to a sensitivity of 98% (44 of 45). PCR analysis revealed the presence of HPV DNA in the cytological suspension of 13 patients (13 of 65, 20%) with simultaneous p16(INK4a) /Ki67 expression by the tumor cells in 11 of these HPV DNA-positive samples (11 of 13, 85%) - a staining pattern that is strongly associated with a carcinogenic HPV infection., Conclusions: A simultaneous immunocytochemical detection of p16(INK4a) and Ki67 can reliably be performed on liquid-based cytological smears from HNSCC patients using a CINtec PLUS kit. In addition, the same cytological material can be used for the detection of HPV DNA by specific PCR. The combined results of both techniques enable better discrimination between latent and carcinogenic HPV infections as well as HPV-negative cases and thus can provide information on the prognosis of HNSCC patients and facilitate therapeutic decisions., (© 2014 American Cancer Society.)