SEC62 Expression Research Articles

Expression of 3q Oncogene SEC62 Predicts Survival in Head and Neck Squamous Cell Carcinoma Patients Treated with Primary Chemoradiation.

Primary chemoradiotherapy (CRT) is an established treatment option for locally advanced head and neck squamous cell carcinomas (HNSCC) usually combining intensity modified radiotherapy with concurrent platinum-based chemotherapy. Though the majority of patients can be cured with this regimen, treatment response is highly heterogeneous and can hardly be predicted. SEC62 represents a metastasis stimulating oncogene that is frequently overexpressed in various cancer entities and is associated with poor outcome. Its role in HNSCC patients undergoing CRT has not been investigated so far. A total of 127 HNSCC patients treated with primary CRT were included in this study. The median follow-up was 5.4 years. Pretherapeutic tissue samples of the primary tumors were used for immunohistochemistry targeting SEC62. SEC62 expression, clinical and histopathological parameters, as well as patient outcome, were correlated in univariate and multivariate survival analyses. High SEC62 expression correlated with a significantly shorter overall survival (p = 0.015) and advanced lymph node metastases (p = 0.024). Further significant predictors of poor overall and progression-free survival included response to therapy (RECIST1.1), nodal status, distant metastases, tobacco consumption, recurrence of disease, and UICC stage. In a multivariate Cox hazard proportional regression analysis, only SEC62 expression (p = 0.046) and response to therapy (p < 0.0001) maintained statistical significance as independent predictors of the patients' overall survival. This study identified SEC62 as an independent prognostic biomarker in HNSCC patients treated with primary CRT. The role of SEC62 as a potential therapeutic target and its interaction with radiation-induced molecular alterations in head and neck cancer cells should further be investigated.

Dual Sec62/Ki67 immunocytochemistry of liquid-based cytological preparations represents a highly valid biomarker for non-invasive detection of head and neck squamous cell carcinomas.

Head and neck squamous cell carcinomas (HNSCC) are frequently diagnosed in advanced stages, which limits therapeutic options and results in persistently poor patient outcomes. The aim of this study was to use liquid-based swab cytology (LBC) in combination with dual immunocytochemical detection of migration and proliferation markers Sec62 and Ki67 in order to allow non-invasive early detection of HNSCC as well as to analyse the diagnostic validity of this method for predicting the malignancy of suspicious oral lesions. 104 HNSCC patients and 28 control patients, including healthy patients (n = 17), papilloma (n = 1) and leukoplakia patients (n = 10), were included in this study. For all patients, an LBC swab followed by simultaneous immunocytochemical detection of Sec62 and Ki67 was performed. Immunocytochemical as well as cytopathological results were correlated with histological diagnoses and clinical findings. All HNSCC patients (100%) showed dual Sec62/Ki67 positivity, and all control patients except for the papilloma patient were negative for Sec62/Ki67 (96.4%), resulting in a 100% sensitivity and 96.4% specificity of Sec62/Ki67 dual stain for non-invasive detection of HNSCC. The positive predictive value was 99% and the negative predictive value was 100%. Sec62 expression levels showed a positive correlation with tumour de-differentiation (p = 0.0489). Simultaneous immunocytochemical detection of Sec62/Ki67 using LBC represents a promising non-invasive and easy-to-apply tool for the early detection of HNSCC in routine clinical practice. This novel technique can help to avoid incisional biopsies and reduce the frequency with which general anaesthesia is used in diagnostic procedures in patients with suspicious oral lesions.

The 3q Oncogene SEC62 Predicts Response to Neoadjuvant Chemotherapy and Regulates Tumor Cell Migration in Triple Negative Breast Cancer.

In the absence of targeted treatment options, neoadjuvant chemotherapy (NACT) is applied widely for triple-negative breast cancer (TNBC). Response to NACT is an important parameter predictive of oncological outcomes (progression-free and overall survival). An approach to the evaluation of predictive markers enabling therapy individualization is the identification of tumor driver genetic mutations. This study was conducted to investigate the role of SEC62, harbored at 3q26 and identified as a driver of breast cancer pathogenesis, in TNBC. We analyzed SEC62 expression in The Cancer Genome Atlas database, and immunohistologically investigated SEC62 expression in pre- and post-NACT tissue samples from 64 patients with TNBC treated at the Department of Gynecology and Obstetrics/Saarland University Hospital/Homburg between January 2010 and December 2018 and compared the effect of SEC62 on tumor cell migration and proliferation in functional assays. SEC62 expression dynamics correlated positively with the response to NACT (p ≤ 0.01) and oncological outcomes (p ≤ 0.01). SEC62 expression stimulated tumor cell migration (p ≤ 0.01). The study findings indicate that SEC62 is overexpressed in TNBC and serves as a predictive marker for the response to NACT, a prognostic marker for oncological outcomes, and a migration-stimulating oncogene in TNBC.

Abstract P6-14-18: Effect of 3q oncogene SEC62 on migration and proliferation of triple-negative breast cancer cells

Abstract Background Chromosome 3q26 amplifications represent a frequent alteration in various cancer entities including breast cancer. SEC62 – a 3q26 encoded gene – was identified as a potential onco- and tumor-driver gene for the pathogenesis of breast cancer. Although the precise physiological function of the respective protein Sec62 is not completely understood, Sec62 seems to induce an increased stress tolerance, enhanced cell migration and invasive potential in SEC62 overexpressing cells. SEC62 overexpressing breast cancer patients have been shown to have a higher rate of lymph node metastasis and poorer overall prognosis. Hence, we aimed to further evaluate the effect of Sec62 for triple-negative breast cancer by targeting cell migration and proliferation of triple-negative cell lines altered in their SEC62 expression. Objectives The aim of this study was to investigate the role of Sec62 for triple-negative breast cancer in cell culture using functional analyzes comparing cell migration and cell proliferation in triple-negative cell lines using the effects of siRNA-mediated Sec62 depletion in vitro. Material&amp; Methods In this study, three SEC62 gene silencing experiments each with two different siRNAs directed against the SEC62 mRNA were carried out in comparison to a control siRNA in combination with cell proliferation and cell migration tests plus Western blots for the triple-negative breast cancer cell line CAL120 in order to determine the suspected causal relationship between SEC62- overexpression and an increased cell migration and thus an enhanced invasion potential of the cancer cells. The cell proliferation was examined in real time in the 96 well xCELLigence system and the cell migration using Fluoroblock without matrigel using fluorescence microscopy. Results In cell migration assays, the median migrated cell number in the control siRNA group was 263 (241-279), the cell number in the groups of the two siRNAs directed against the Sec62 mRNA was 72 (70-149) and 178 (96-276) (p &amp;lt; 0.01). In cell proliferation assays, the median cell index in the control siRNA group was 7.5 (7.4-7.6), while it was 7.4 (7.3-7 .5) and 7.6 (7.5-7.7) (p=0.37). In the first analyzes of the medians of the three gene silencing experiments of the cell line CAL120, the expected negative effect of the SEC62-siRNA on cell migration is confirmed, while, as expected, the effect on cell proliferation remains unchanged with decreasing Sec62 content. Conclusion In this in vitro study using cell migration and cell proliferation assays we found a correlation between SEC62 overexpression and increased cell migration. This implies a potential association between Sec62 and an increased tumor cell invasion in triple-negative breast cancer. Citation Format: Julia SM Zimmermann, Annika Cullmann, Askin Kaya, Merle Doerk, Maximilian Linxweiler, Marc P Radosa, Sven Lang, Martin Jung, Erich F Solomayer, Julia C Radosa. Effect of 3q oncogene SEC62 on migration and proliferation of triple-negative breast cancer cells [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-14-18.

Effect of the 3q26-coding oncogene SEC62 as a potential prognostic marker in patients with ovarian neoplasia.

With approximately 220,000 newly diagnosed cases per year, ovarian cancer is among the most frequently occurring cancers among women and the second leading cause of death from gynecological malignancies worldwide. About 70% of these cancers are diagnosed in advanced stages (FIGO IIB-IV), with a 5-year survival rate of 20-30%. Due to the poor prognosis of this disease, research has focused on its pathogenesis and the identification of prognostic factors. One possible approach for the identification of biological markers is the identification of tumor entity-specific genetic "driver mutations". One such mutation is 3q26 amplification in the tumor driver SEC62, which has been identified as relevant to the pathogenesis of ovarian cancer. This study was conducted to investigate the role of SEC62 in ovarian malignancies. Patients with ovarian neoplasias (borderline tumors of the ovary and ovarian cancer) who were treated between January 2007 and April 2019 at the Department of Gynecology and Obstetrics, Saarland University Hospital, were included in this retrospective study. SEC62 expression in tumor tissue samples taken during clinical treatment was assessed immunohistochemically, with the calculation of immunoreactivity scores according to Remmele and Stegner, Pathologe, 1987, 8, 138-140. Correlations of SEC62 expression with the TNM stage, histological subtype, tumor entity, and oncological outcomes (progression-free and overall survival) were examined. The sample comprised 167 patients (123 with ovarian cancer and 44 with borderline tumors of the ovary) with a median age of 60 (range, 15-87)years. At the time of diagnosis, 77 (46%) cases were FIGO stage III. All tissue slides showed SEC62 overexpression in tumor cells and no SEC62 expression in other cells. Median immunoreactivity scores were 8 (range, 2-12) for ovarian cancer and 9 (range, 4-12) for borderline tumors of the ovary. Patients with borderline tumors of the ovary as well as patients with ovarian cancer and an immunoreactive score (IRS) ≤ 9 showed an improved overall survival compared to those presenting with an IRS score >9 (p = 0.03). SEC62 seems to be a prognostic biomarker for the overall survival of patients with ovarian malignancies.

Role of the SEC62 gene in dermato-oncology - impact on tumor cell biology, prognostication, and personalized therapy management.

The SEC62 gene encodes for a transmembrane protein of the endoplasmic reticulum (ER). Sec62 protein is involved in the post-translational transport of secretory and membrane-bound proteins in eukaryotic cells, regulates intracellular calcium homeostasis through direct interaction with the Sec61 channel and makes a decisive contribution to the cellular compensation of ER stress in the context of recovER-phagy. A significantly increased expression of the SEC62 gene has already been demonstrated in various tumor entities. First approaches of a targeted therapy have been tested for various tumor entities in vitro and in vivo with promising results that motivate further preclinical and clinical studies. Nevertheless, many questions remain unanswered, in particular with regard to the molecular mechanisms underlying the observed clinical effects, and require further investigation in future studies. The protein also plays a relevant role in dermato-oncology. The overexpression of SEC62 in atypical fibroxanthomas and malignant melanomas has already been demonstrated and a correlation of SEC62 expression with various clinical and pathological features has been observed. Future studies, especially in vivo and clinical, will show whether Sec62 can be established as a prognostic marker in dermato-oncology and whether it can serve as a starting point for targeted therapy.

Antagonizing Sec62 function in intracellular Ca2+ homeostasis represents a novel therapeutic strategy for head and neck cancer.

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 P4-06-06: Role of lymphatic SEC62 expression in prediction of treatment response in patients undergoing neoadjuvant chemotherapy for primary breast cancer

Abstract Background Chromosome 3q26 amplifications have been shown to represent a frequent alteration in various cancer entities including breast cancer. SEC62 - a 3q26 encoded gene - was identified as a potential onco- and tumor-driver gene for the pathogenesis of breast cancer. Sec62 seems to induce an increased stress tolerance, enhanced cell migration and proliferation in SEC62 overexpressing cells. Patients with SEC62 overexpressing breast cancer have been shown to have a higher rate of lymph node metastasis and poorer overall prognosis. Hence, we aspired to further evaluate the function of lymphatic SEC62 expression and its predictive role on the response to neoadjuvant chemotherapy. Objectives We aimed to assess the role of lymph node SEC62 expression as a predictive biomarker for response to neoadjuvant chemotherapy, besides we sought to evaluate potential differences in SEC62 expression levels in metastatic lymph node core biopsies and final pathology specimen according to breast cancer subtype. Material &amp; Methods All nodal positive patients treated for primary breast cancer with neoadjuvant chemotherapy at the Department of Gynaecology and Obstetricts, Saarland University Hospital, Homburg, Germany between 01/2009 and 12/2019 were enrolled in this retrospective study. We analyzed SEC62 expression in tissue samples by immunohistochemistry (IHC). Sec62 immunoreactivity was evaluated using the immunoreactive score (IRS) according to Remmele and Stegner (0-12). For the assessment of the Sec62 protein content of the tumor cells, we rated Sec62 “low” for a score of 0-8, and “high” for 9-12 as described in previous publications. IHC was performed on initial lymph node core biopsy (CB) tissue (pre-treatment) or sentinel node biopsy specimen and on definite pathology specimen (PS) obtained during axillary dissection after completion of neoadjuvant chemotherapy.SEC62 expressions in both samples were compared and correlated with response to neoadjuvant chemotherapy, evaluated pathologically using the semi-quantitative response to neoadjuvant chemotherapy scoring system by Sinn et al. ranging from 0 (no effect) to 4 (no tumor detectable). Results 103 patients were assessed for eligibility. 15 cases were excluded, due to incomplete clinical information or insufficient slide quality, leaving 88 patients for final analysis. Median patient age was 55 (32-78) years and median response to neoadjuvant chemotherapy score of 2 (0-4). 11 (12.5%) patients had luminal A, 31 (35.2%) luminal B, 21 (23.9%) Her2/neu positive and 25 (28.4%) triple negative breast cancer. Median SEC62 expression in lymph node core biopsies was significantly higher compared to expression in final specimen (p&amp;lt;0.01). While no differences in basic expression of SEC62 in CB and the response to neoadjuvant chemotherapy were detected, patients with an IRS score ≤ 8 in PS and patients with a difference of IRS score ≥6 between CB and PS showed a significantly higher median response to neoadjuvant chemotherapy score compared to other patients (p&amp;lt; 0.01). Analyzing median Sec62 IHC expression in final pathology specimen, we observed significantly lower Sec62 scores for Her2/neu positive and triple negative patients compared to other subtypes (p&amp;lt;0.01). Median SEC62 expression showed the highest decrease between CB and PS in Her2/neu positive and triple negative patients. Regarding response to neoadjuvant chemotherapy, the effects described above could be observed in all breast cancer subtypes, but were strongest in triple negative patients. Conclusion We identified lymph node SEC62 expression as a promising biomarker for prediction of response to neoadjuvant chemotherapy in breast cancer patients. This effect seems to be strongest in patients with triple negative breast cancer. Citation Format: Julia Zimmermann, Anna Jung, Merle Doerk, Mariz Kasoha, Barbara Linxweiler, Maximilian Linxweiler, Mathias Wagner, Rainer Bohle, Marc Radosa, Erich Solomayer, Julia C Radosa. Role of lymphatic SEC62 expression in prediction of treatment response in patients undergoing neoadjuvant chemotherapy for primary breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P4-06-06.

Sec62 promotes gastric cancer metastasis through mediating UPR-induced autophagy activation.

Sec62 is a membrane protein of the endoplasmic reticulum that facilitates protein transport. Its role in cancer is increasingly recognised, but remains largely unknown. We investigated the functional role of Sec62 in gastric cancer (GC) and its underlying mechanism. Bioinformatics, tissue microarray, immunohistochemistry (IHC), western blotting (WB), quantitative polymerase chain reaction (qPCR), and immunofluorescence were used to examine the expression of target genes. Transwell, scratch healing assays, and xenograft models were used to evaluate cell migration and invasion. Transmission electron microscopy and mRFP-GFP-LC3 double-labeled adenoviruses were used to monitor autophagy. Co-immunoprecipitation (CO-IP) was performed to evaluate the binding activity between the proteins. Sec62 expression was upregulated in GC, and Sec62 upregulation was an independent predictor of poor prognosis. Sec62 overexpression promoted GC cell migration and invasion both in vitro and in vivo. Sec62 promoted migration and invasion by affecting TIMP-1 and MMP2/9 balance. Moreover, Sec62 could activate autophagy by upregulating PERK/ATF4 expression and binding to LC3II with concomitant FIP200/Beclin-1/Atg5 activation. Furthermore, autophagy blockage impaired the promotive effects of Sec62 on GC cell migration and invasion, whereas autophagy activation rescued the inhibitory effect of Sec62 knockdown on GC metastasis. Notably, Sec62 inhibition combined with autophagy blockage exerted a synergetic anti-metastatic effect in vitro and in vivo. Sec62 promotes GC metastasis by activating autophagy and subsequently regulating TIMP-1 and MMP2/9 balance. The activation of autophagy by Sec62 may involve the unfolded protein response (UPR)-related PERK/ATF4 pathway and binding of LC3II during UPR recovery involving FIP200/Beclin-1/Atg5 upregulation. Specifically, the dual inhibition of Sec62 and autophagy may provide a promising therapeutic strategy for GC metastasis.

Sec62 promotes stemness and chemoresistance of human colorectal cancer through activating Wnt/\u03b2-catenin pathway

BackgroundCancer stem cell (CSC)-related chemoresistance leads to poor outcome of the patients with colorectal cancer (CRC). In this study, we identified the chemoresistance-relevant molecules and decipher the involved mechanisms to provide potential therapeutic target for CRC. We focused on Sec62, a novel target with significantly increased expression in chemoresistant CRC tissues, and further investigated its role in the progression of CRC.MethodsThrough analyzing the differentially-expressed genes between chemoresistant and chemosensitive CRCs, we selected Sec62 as a novel chemoresistance-related target in CRC. The expression and clinical significance of Sec62 were determined by immunoblotting and immunohistochemistry in tissues and cell lines of CRC. The roles of Sec62 in drug resistance, stemness and tumorigenesis were evaluated in vitro and in vivo using functional experiments. GST pull-down, western blot, coimmunoprecipitation and Me-RIP assays were performed to further explore the downstream molecular mechanisms.ResultsSec62 upregulation was associated with the chemoresistance of CRC and poor outcome of CRC patients. Depletion of Sec62 sensitized CRC cells to chemotherapeutic drugs. Sec62 promoted the stemness of CRC cells through activating Wnt/β-catenin signaling. Mechanistically, Sec62 bound to β-catenin and inhibited the degradation of β-catenin. Sec62 competitively disrupted the interaction between β-catenin and APC to inhibit the β-catenin destruction complex assembly. Moreover, Sec62 expression was upregulated by the m6A-mediated stabilization of Sec62 mRNA.ConclusionsSec62 upregulated by the METTL3-mediated m6A modification promotes the stemness and chemoresistance of CRC by binding to β-catenin and enhancing Wnt signalling. Thus, m6A modification-Sec62-β-catenin molecular axis might act as therapeutic targets in improving treatment of CRC.

Expression of SEC62 Oncogene in Benign, Malignant and Borderline Melanocytic Tumors-Unmasking the Wolf in Sheep's Clothing?

Simple SummaryAmplification and overexpression of the SEC62 oncogene was reported in a variety of human cancers and was associated with poor prognosis as well as lymph node and distant metastases. In this study, SEC62 expression was analyzed in benign, borderline, and malignant melanocytic lesions of 209 patients. We found the highest expression in Spitz nevi, followed by melanoma metastases, primary melanoma, congenital nevi, and blue nevi. In melanoma patients, high Sec62 levels correlated with shorter overall and progression-free survival. Significantly higher Sec62 levels were found in melanomas with lymph node and distant metastases compared with those without. Taken together, these data suggest a relevant role of SEC62 as a metastasis-stimulating oncogene in melanoma development, which represents a promising therapeutic target.SEC62 oncogene located at chromosomal region 3q26 encodes for a transmembrane protein of the endoplasmic reticulum (ER) and is expressed at high levels in numerous human malignancies. SEC62 overexpression has been associated with worse prognosis and high risk for lymphatic and distant metastases in head and neck cancer, cervical cancer, hepatocellular cancer, and lung cancer. However, its role in the development and tumor biology of melanocytic lesions has not been investigated so far. An immunohistochemical study including 209 patients with melanocytic lesions (malignant melanoma (MM), n = 93; melanoma metastases (MET), n = 28; Spitz nevi (SN), n = 29; blue nevi (BN), n = 21; congenital nevi (CN), n = 38) was conducted and SEC62 expression was correlated with clinical data including patient survival and histopathological characteristics. SN showed the highest SEC62 expression levels followed by MET, MM, CN, and BN. High SEC62 expression correlated with a shorter overall and progression-free survival in MM patients. Additionally, high Sec62 levels correlated significantly with higher tumor size (T stage), the presence of tumor ulceration, and the presence of lymph node as well as distant metastases. Strikingly, SEC62 expression showed a strong correlation with Clark level. Taken together, these data demonstrate that SEC62 is a promising prognostic marker in MM and has the potential to predict biological behavior and clinical aggressiveness of melanocytic lesions.

Globular adiponectin alleviates chronic intermittent hypoxia-induced H9C2 cardiomyocytes apoptosis via ER-phagy induction

ABSTRACT This study evaluated the effects of endoplasmic reticulum autophagy (ER-phagy) and globular adiponectin (gAPN) on chronic intermittent hypoxia (CIH)-induced H9C2 cardiomyocytes injury while investigating potential mechanisms of action. The CIH model of H9C2 cardiomyocytes was established in this study. CCK-8 assay was used to determine cell viability post-exposure to various CIH times and gAPN concentrations. Flow cytometry was used to observe H9C2 cardiomyocytes apoptosis and immunofluorescence was used to measure ER-phagy and SEC62 activation. Western blot was used to observe ER stress and AMPK pathway. Results indicated that ER stress was activated in H9C2 cardiomyocytes exposed to CIH. Inhibition of ER stress reduced CIH-induced cell apoptosis. gAPN attenuated CIH-induced ER stress and H9C2 cardiomyocytes apoptosis. ER-phagy and SEC62 protein level were induced by CIH, while gAPN highly enhanced these changes. Inhibition of SEC62 expression reduced ER-phagy and increased ER stress and H9C2 cardiomyocytes apoptosis. Moreover, gAPN induced AMPK expression. Inhibition of AMPK expression reduced SEC62-mediated ER-phagy and increased the H9C2 cardiomyocytes apoptosis. Altogether, our study suggested that gAPN upregulated SEC62-mediated ER-phagy to extenuate ER stress, and mitigated H9C2 cardiomyocytes apoptosis induced by CIH through AMPK activation.

Abstract P1-10-28: Role of Sec62 in prediction of response to neoadjuvant chemotherapy in patients with primary breast cancer

Abstract Background Chromosome 3q26 amplifications have been shown to represent a frequent alteration in various cancer entities including breast cancer. SEC62 - a 3q26 encoded gene - was identified as a potential oncogene and tumor-driver-gene for the pathogenesis of breast cancer. Although the precise physiological function of the respective protein Sec62 is not completely understood, it is hypothesized, that Sec62 induces an increased stress tolerance and enhances cell migration in SEC62 overexpressing cells resulting in a high rate of lymphatic metastasis and poorer overall prognosis in tumor tissue with a high Sec62 expression. We sought to further elucidate the function of Sec62 in breast cancer with special focus on its predictive role on the response to neoadjuvant chemotherapy. Materials and Methods All patients treated for primary breast cancer with neoadjuvant chemotherapy at the Department of Gynaecology and Obstetrics, Saarland University Hospital, Homburg, Germany between 01/2007 and 12/2018 were enrolled in this study. The study was approved by the Saarland institutional review board. Sec62 protein levels were analyzed in tumor tissue samples using immunohistochemistry (IHC). Sec62 immunoreactivity was evaluated by three independent examiners using the immunoreactive score (IRS) according to Remmele and Stegner (0-12). For the assessment of Sec62 protein expression in tumor cells, we rated Sec62 “negative” 0-3, “low” for a score of 4-8 and “high” for 9-12 as described in previous publications. IHC was performed on initial breast core biopsy (CB) tissue (pre-treatment) and on definite pathology specimen (PS) obtained during breast surgery after completion of neoadjuvant chemotherapy. Sec62 expression in both samples were compared and correlated with response to neoadjuvant chemotherapy evaluated pathologically using the semi-quantitative response to neoadjuvant chemotherapy scoring system by Sinn et al. ranging from 0 (no effect) to 4 (no tumor detectable). Additionally, Sec62 expression in tumor tissue was compared with the histologically tumor-free tissue of the same patient. Sec62 expression levels and correlation with response to neoadjuvant chemotherapy were compared using Wilcoxon signed-rank, Mann-Whitney and Pearson`s chi square test. Results 203 patients were assessed for eligibility. Nine cases were excluded, due to incomplete clinical information or insufficient slide quality, leaving 194 patients for final analysis. Median patient age was 54 (22-86) years and median response to neoadjuvant chemotherapy score of 2 (0-4). 20 patients (10 %) had luminal A, 46 (24 %) luminal B, 60 (31 %) Her2/neu positive and 68 (35 %) triple negative breast cancer. All analyzed slides showed an over-expression of Sec62 in breast cancer cells but no positive staining of physiologic breast tissue cells. Median Sec62 expression in core biopsies (CB) (8 (2-12)) was significantly higher compared to expression in final specimen (PS) (4 (0-12); p ≤ 0.01). Median difference between Sec62 expression of CB and PS was 2 (0-4). Regarding response to neoadjuvant chemotherapy patients with a low Sec62 expression in PS and a difference ≥ 6 between CB and PS showed a significant higher median response score compared to other patients (2 (0-4) vs. 1 (0-2); p ≤ 0.01; 4 (1-4) vs. 1 (0-4); p ≤ 0.01). When looking at breast cancer subtypes these effects were strongest in Her2/positive and triple negative patients and median Sec62 expression showed the highest decrease between CB and PS in these two subgroups (6 (-3-12); 2 (-6-12)). Conclusion We identified Sec62 as a potential biomarker for prediction of response to neoadjuvant chemotherapy in patients with primary breast cancer. This effect was observed to be strongest in patients with Her2/positive and triple negative breast cancer. Citation Format: Julia Caroline Radosa, Mariz Kasoha, Merle Doerk, Barbara Linxweiler, Maximilian Linxweiler, Florian Bochen, Rainer M Bohle, Matthias Wagner, Marc P Radosa, Erich-Franz Solomayer, Zoltan Ferenc Takacs. Role of Sec62 in prediction of response to neoadjuvant chemotherapy in patients with primary breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P1-10-28.

Identification of 3q oncogene SEC62 as a marker for distant metastasis and poor clinical outcome in invasive ductal breast cancer.

In previous studies, we have shown that SEC62 has an essential function in cell migration, epithelial-to-mesenchymal transition, and endoplasmic reticulum stress tolerance of cancer cells. SEC62 expression correlated with distant and lymph node metastasis and poor outcome in different cancer entities. In this initial study, we investigated SEC62 expression and its possible role as a prognostic and predictive biomarker in breast cancer (BC). Formalin-fixed, paraffin-embedded tissue samples of 53 BC patients were analyzed by immunohistochemistry. The immunoreactive score (IRS) according to Remmele and Stegner was evaluated and correlated with clinico-pathological findings and overall survival (OS). We found increased SEC62 protein levels in tumor tissue compared to tumor-free tissue samples from the same patients. Tumors with high SEC62 expression (IRS>8), or containing isolated cells with high SEC62 staining intensity, independent of the IRS, had more frequently distant metastases (48.4% vs. 18.2%; p = 0.024 and 47.4 vs. 6.7%; p = 0.005, respectively). Overall survival was significantly worse in BC patients with high SEC62 expression (SEC62 IRS>8) (54.8% vs. 81.8%; p = 0.011) and in cases with isolated high-intensity SEC62 staining cells independently of SEC62 IRS (55.3% vs 93.3%; p = 0.024). We are the first to describe the SEC62 expression and its correlation to clinicopathological parameters in mammary carcinoma. Our results suggest that SEC62 expression may serve as a prognostic marker for patients with invasive ductal breast cancer.

Sec62/Ki67 dual staining in cervical cytology specimens: a new marker for high-grade dysplasia.

In the previous studies, we demonstrated that Sec62 is essential for tumor cell migration, epithelial-to-mesenchymal transition, and intracellular stress tolerance. An increase in Sec62 expression correlated with an increase in cervical dysplasia severity in liquid-based cytology specimens. Ki67 is an established proliferation marker. Thus, in this study, we examined a method of Sec62/Ki67 dual staining for the detection of high-grade dysplasia and cancer in cervical liquid-based cytology specimens. Sec62/Ki67 dual staining was performed on 100 cervical liquid-based cytology specimens. The staining results were correlated with cytological, immunocytological (p16/Ki67), colposcopic, and histological findings. All 56 (n = 56, 100%) cases of cervical intraepithelial neoplasia grade 3 and cervical cancer (CIN3+ lesions) were positive for Sec62/Ki67 staining, while low-grade lesions and normal cells were negative. Sec62/Ki67 staining was highly sensitive and specific for the detection of CIN2+ and CIN3+ lesions (94.37%; 100% and 100%; 84.09%, respectively). Sec62/Ki67 dual-staining immunocytochemistry is a promising cytological tool for interpreting high-grade squamous lesions in cytological specimens and for assessing the risk of progression to cancer.

Expression of 3q oncogene SEC62 in atypical fibroxanthoma-immunohistochemical analysis of 41 cases and correlation with clinical, viral and histopathologic features.

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.

Effect of 3q oncogenes SEC62 and SOX2 on lymphatic metastasis and clinical outcome of head and neck squamous cell carcinomas.

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.

Sec62 Bridges the Gap from 3q Amplification to Molecular Cell Biology in Non–Small Cell Lung Cancer

The molecular carcinogenesis of lung cancer has yet to be clearly elucidated. We investigated the possible oncogenic function of SEC62 in lung cancer, which was predicted based on our previous findings that lung and thyroid cancer tissue samples exhibited increased Sec62 protein levels. The SEC62 gene locus is at 3q26.2, and 3q amplification is reportedly the most common genomic alteration in non-small cell lung cancer. We analyzed SEC62 mRNA and protein levels in tissue samples from lung cancer patients by real-time quantitative PCR, Western blot, and IHC and found significantly increased SEC62 mRNA and protein levels in tumors compared with tumor-free tissue samples from the same patients. Correlation analyses revealed significantly higher Sec62 levels in tumors with lymph node metastases compared with nonmetastatic tumors, as well as in poorly compared with moderately differentiated tumors. On the basis of these promising results, we examined the role of Sec62 in cancer cell biology in vitro. Cell migration assays with lung and thyroid cancer cells showed distinct stimulation of migration in SEC62-overexpressing cells and inhibition of migration in Sec62-depleted cells. Moreover, we found that SEC62 silencing sensitized the cells to thapsigargin-induced endoplasmic reticulum stress. Thus, our results indicate that SEC62 represents a potential candidate oncogene in the amplified 3q region in cases of non-small cell lung cancer and harbors various functions in cancer cell biology.

Sec62 protein level is crucial for the ER stress tolerance of prostate cancer

We previously reported that over-expression of the SEC62 gene is a widespread phenomenon in prostate cancer. Since the use of endoplasmic reticulum (ER) stress-inducing substances such as thapsigargin in prostate cancer therapy is widely discussed in the literature, we investigated the influence of Sec62 protein content on the cellular response to these drugs. Growth effects were analyzed by real-time cell analysis and viability tests in DU145-cells representing an increased SEC62 expression or PC3- and LNCaP-cells representing a similar SEC62 expression compared to non-tumor cells. Ca(2+) -imaging in an established HeLa-system with fluorescent dye was used to study molecular effects of Sec62 depletion. We found a lower propensity toward apoptotic cell death after thapsigargin treatment for DU145 cells compared to PC3 or LNCaP and siRNA-mediated silencing of SEC62 resulted in a reduced viability of thapsigargin-treated PC3 cells, indicating that Sec62 functions in cellular stress response. Measurement of cytosolic [Ca(2+) ] demonstrated the influence of Sec62 on the cellular response to thapsigargin on a molecular level. Using real-time cell analysis, we observed the loss of androgen stimulation of LNCaP cells in the presence of thapsigargin, and an additional negative effect on cell growth of Sec62 depletion. Also, for PC3- and DU145-cells Sec62 depletion inhibited growth after thapsigargin treatment. Our data indicate a crucial function of Sec62 in the response to thapsigargin-induced ER stress. This will be of great significance on the background of elevated Sec62 protein levels in prostate cancer cells when treatment with thapsigargin analogs is considered.