Growth of normal oral keratinocytes and squamous cell carcinoma cells in a novel protein-free defined medium

Summary A novel protein-free synthetic medium was developed for the culture of normal human oral keratinocytes. This medium, designated PFM-7, supports the serial cultivation of primary or secondary normal oral keratinocytes in protein-free, chemically defined conditions. Normal oral keratinocytes in PFM-7 exhibited nearly equal growth in mass culture without noticeable changes in morphology, response to added growth factors, or gene expression of growth factors and their receptors, compared to cells in Keratinocyte-SFM containing epidermal growth factor and bovine pituitary extract. Furthermore, PFM-7 supported the serial subcultivation of human squamous cell carcinoma cells and enabled both normal and malignant oral squamous cells derived from the same patient to grow under the same protein-free defined conditions. These results indicate that PFM-7 can be used for precise investigations of growth mechanisms, cell products, and gene expression associated with carcinogenesis of human epidermal cells.     

Epigenetic inactivation of SPINT2 is associated with tumor suppressive function in esophageal squamous cell carcinoma

Hepatocyte growth factor activator inhibitor type 2 (SPINT2), a Kunitz-type serine proteinase inhibitor, has been identified as a putative tumor suppressor gene silenced by promoter methylation. We aimed to investigate whether SPINT2 might act as an esophageal squamous cell carcinoma (ESCC) tumor suppressor gene. Four ESCC cell lines, Fifty-two ESCC tissues and twenty-nine neighboring non-cancerous tissues were included in this study. The expression of SPINT2 was monitored by real time PCR. Bisulfite genomic sequencing and methylation-specific PCR were used to analyze methylation status. The effect of SPINT2 on cell proliferation and apoptosis in EC109 and EC9706 cells was observed by CCK-8 assay and flow cytometric analysis. We found that silencing of SPINT2 was associated with promoter methylation in ESCC cell lines. The densely methylated SPINT2 promoter region was confirmed by bisulfite genomic sequencing. Ectopic expression of SPINT2 inhibited cell proliferation through inducing cell apoptosis in vitro. Furthermore, methylation-specific PCR analysis revealed that SPINT2 promoter methylation was prominent in carcinoma tissues (52.08%) compared with neighboring non-cancerous tissues (22.58%). Kaplan–Meier analysis showed that patients with SPINT2 hypermethylation had shorter survival time. The tumor suppressor gene of SPINT2 is commonly silenced by promoter hypermethylation in human ESCC and SPINT2 hypermethylation is correlated with poor overall survival, implicating SPINT2 is an underlying prognostic marker for human ESCC.     

miR-214通过调控Notch1信号对口咽鳞状细胞癌细胞株增殖、侵袭及凋亡的作用机制研究

目的研究miR-214通过调控Notch1信号对口咽鳞状细胞癌（OSCC）细胞株增殖、侵袭及凋亡的作用机制。 方法在ATCC细胞库购买OSCC细胞株,分为3组：抑制组（IN组）、模拟组（SI组）及对照组（CO组）。通过Western blot法、qRT-PCR法、TUNEL法、侵袭实验及CCK-8法分析3组癌细胞中Notch1的蛋白、mRNA表达水平、细胞凋亡、迁移及增殖能力的差异性,三组间比较采用单因素方差分析,组间两两比较采用LSD-t检验。 结果IN、SI、CO组细胞内miR-214mRNA表达量分别为1.15±0.26,3.34±0.89,2.08±0.67,SI组分别与IN组、CO组比较,差异具有统计学意义（t = 5.281,P = 0.002;t = 2.529,P = 0.045）;SI组、IN组的Notch1-UTR表达分别为0.42±0.11、0.86±0.09,差异具有统计学意义（t = 5.362,P = 0.006）;IN、SI、CO组的OSCC细胞凋亡率分别为（0.78±0.10）﹪、（0.32±0.06）﹪、（0.56±0.12）﹪,IN组分别与CO组、SI组比较,差异具有统计学意义（t = 3.149,P = 0.020;t = 8.823,P < 0.001）;IN、SI、CO组癌细胞的增殖率分别为（0.65±0.05）﹪、（1.26±0.06）﹪、（1.89±0.04）﹪,IN组与SI组、IN组与CO组比较,差异具有统计学意义（t = 11.056,P < 0.001;t = 27.394,P < 0.001）,CO组与SI组比较,差异具有统计学意义（t = 12.365,P < 0.001）;IN、SI、CO组癌细胞侵袭率分别为（0.13±0.02）﹪、（0.89±0.13）﹪、（0.48±0.11）﹪,SI组与CO组、SI组与IN组比较,差异具有统计学意义（t = 4.176,P = 0.006;t = 10.147,P < 0.001）;IN、SI、CO组的Notch1蛋白含量分别为：2.38±1.34、0.94±0.23、1.76±0.67,SI组与CO组、SI组与IN组比较,差异具有统计学意义（t = 2.588,P = 0.041;t = 2.368,P = 0.056）;IN、SI、CO组的Notch1 mRNA表达量分别为4.26±1.06、1.45±0.38、2.46±0.87,IN组与CO组、IN组与SI组比较,差异具有统计学意义（t = 2.935,P = 0.026;t = 5.583,P = 0.001）。 结论miR-214可能与OSCC细胞株增殖呈负相关,在细胞中miR-214含量升高,可能抑制Notch1信号通路表达,从而促进癌细胞增长、侵袭,抑制癌细胞凋亡。     

Differentiation of normal and tumoral human keratinocytes cultured on dermis: Reconstruction of either normal or tumoral architecture

Summary Normal human keratinocytes isolated from skin and squamous carcinoma cells established from a human tumor (TR146 cell line) both exhibit limited morphologic differentiation when they are grown on conventional plastic dishes. However, when they are seeded on human de-epidermized dermis and cultured at the air-liquid interface, they are able to reform an epithelium having the morphology of the tissue of origin (i.e. skin or squamous carcinoma). The distribution in such reconstructed tissues of differentiation markers such as bullous pemphigoid antigen, 67K keratin, involucrin, membrane-bound transglutaminase, and filaggrin was very similar to their distribution in normal skin and squamous carcinoma specimens, respectively. The degree of differentiation is for both cell types extremely sensitive to culture conditions such as retinoic acid concentration, emersion of the cultures, etc. These results show that subcultured normal or tumoral keratinocytes are able to recover their specific morphogenetic potential when cultured in an environment close to their in vivo situation.     

Glutaredoxin 3 promotes migration and invasion via the Notch signalling pathway in oral squamous cell carcinoma

Substantial evidence indicates that the alteration of the cellular redox status is a critical factor involved in cell growth and death and results in tumourigenesis. Cancer cells have an efficient antioxidant system to counteract the increased generation of ROS. However, whether this ability to survive high levels of ROS has an important role in the growth and metastasis of tumours is not well understood. Glutaredoxin 3 (GLRX3), also known as TXNL2, Grx3 and PICOT, maintains a low level of ROS, thus contributing to the survival and metastasis of several types of cancer. However, little is known about the role of GLRX3 and the underlying mechanisms that suppress oral squamous cell carcinoma (OSCC) progression. Here, by using immunohistochemical staining, we demonstrated that GLRX3 was overexpressed in human OSCC, and enhanced GLRX3 expression correlated with metastasis and with decreased overall patient survival. Knockdown of GLRX3 in human OSCC cell lines reduced Notch activity by reversing the epithelial–mesenchymal transition (EMT), resulting in the inhibition of in vitro migration and invasion. Importantly, knockdown of GLRX3 triggered the generation of ROS. Furthermore, N-acetyl cysteine (NAC), an ROS scavenger, enhanced the effects of GLRX3 knockdown on Notch-dependent EMT. Collectively, these findings suggested the vital roles of GLRX3 in OSCC progression through its relationship with EMT progression, and these data also suggest that a strategy of blocking ROS to enhance the activity of GLRX3 knockdown warrants further attention in the treatment of OSCC.     

Ivermectin suppresses tumour growth and metastasis through degradation of PAK1 in oesophageal squamous cell carcinoma

Oesophageal squamous cell carcinoma (ESCC), the most common form of oesophageal malignancies in the Asia‐Pacific region, remains a major clinical challenge. In this study, we found that ivermectin, an effective antiparasitic drug that has been approved for patients to orally treat onchocerciasis for over 30 years, displayed potent antitumour activity against ESCC cells in vitro and in nude mice. We demonstrated that ivermectin significantly inhibited cell viability and colony formation, and induced apoptosis through a mitochondrial‐dependent manner in ESCC cells. Ivermectin also abrogated ESCC cell migration, invasion, as well as the protein levels of MMP‐2 and MMP‐9. Mechanistically, ivermectin strongly inhibited the expression of PAK1; by further gain‐ and loss‐of‐function experiments, we confirmed that PAK1 played a crucial role in ivermectin‐mediated inhibitory effects on ESCC cells. In addition, the data indicated that ivermectin promoted PAK1 degradation through the proteasome‐dependent pathway. Additionally, ivermectin synergized with chemotherapeutic drugs including cisplatin and 5‐fluorouracil to induce apoptosis of ESCC cells. Interestingly, the in vivo experiments also confirmed that ivermectin effectively suppressed tumour growth and lung metastasis of ESCC. Collectively, these results indicate that ivermectin exerts a potent antitumour activity against ESCC and is a promising therapeutic candidate drug for ESCC patients, even those carrying metastasis.     

Ectopic coexpression of keratin 8 and 18 promotes invasion of transformed keratinocytes and is induced in patients with cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) results from transformation of epidermal keratinocytes. Invasion of transformed keratinocytes through the basement membrane into the dermis results in invasive cSCC with substantial metastatic potential. To better understand the mechanisms for invasion and metastasis, we compared the protein expression profiles of a non-metastatic transformed mouse keratinocyte line and its metastatic derivative. Keratin 8 (Krt8) and Krt18, not seen in normal keratinocytes, were coexpressed and formed Krt8/18 filaments in the metastatic line. The metastatic line efficiently invaded an artificial basement membrane in vitro owing to the Krt8/18-coexpression, since coexpression of exogenous Krt8/18 in the non-invasive parental line conferred invasiveness. To test whether the Krt8/18-coexpression is induced and is involved in cSCC invasion, we examined specimens from 21 pre-invasive and 24 invasive cSCC patients by immunohistochemistry, and the ectopic Krt8/18-coexpression was almost exclusively found in invasive cSCC. Further studies are needed to examine the clinical significance of ectopic Krt8/18-coexpression in cSCC.     

CA9 transcriptional expression determines prognosis and tumour grade in tongue squamous cell carcinoma patients

CA9 is a member of the carbonic anhydrases’ family, that is often expressed in cancer cells under hypoxic condition. However, the role of CA9 in the molecular mechanisms of tongue squamous cell carcinoma (TSCC) pathogenesis remains unclear. CA9 expression was analysed using the TCGA database, and its influence on survival was performed using Kaplan-Meier, LASSO and COX regression analyses. The correlation between CA9 and immune infiltration was investigated by CIBERSORT and ESTIMATE. Moreover, the relationship between CA9 expression and downstream molecular regulation pathways was analysed by GSEA, GO and WGCNA. CA9 expression correlated with clinical prognosis and tumour grade in TSCC. Moreover, CA9 expression potentially contributes to the regulation of cancer cell differentiation and mediates tumour-associated genes and signalling pathways, including apoptosis, hypoxia, G2M checkpoint, PI3K/AKR/mTOR signalling and TGF-beta signalling pathways. However, the follicular helper T cells, regulatory T cells, immune and stromal scores showed no significance between high and low CA9 expression groups. These findings suggested that CA9 plays a critical role of TSCC prognosis and tumour grade. CA9 expression significantly correlated with the regulation of cell differentiation, various oncogenes and cancer-associated pathways.     

Lysyl oxidase-like 2 represses Notch1 expression in the skin to promote squamous cell carcinoma progression

Lysyl oxidase-like 2 (LOXL2) is involved in a wide range of physiological and pathological processes, including fibrosis and tumor progression, implicating intracellular and extracellular functions. To explore the specific in vivo role of LOXL2 in physiological and tumor contexts, we generated conditional gain- and loss-of-function mouse models. Germ-line deletion of Loxl2 promotes lethality in half of newborn mice mainly associated to congenital heart defects, while Loxl2 overexpression triggers male sterility due to epididymal dysfunction caused by epithelial disorganization, fibrosis and acute inflammation. Remarkably, when challenged to chemical skin carcinogenesis, Loxl2-overexpressing mice increased tumor burden and malignant progression, while Loxl2-deficient mice exhibit the opposite phenotypes. Loxl2 levels in premalignant tumors negatively correlate with expression of epidermal differentiation markers and components of the Notch1 pathway. We show that LOXL2 is a direct repressor of NOTCH1. Additionally, we identify an exclusive expression pattern between LOXL2 and members of the canonical NOTCH1 pathway in human HNSCC. Our data identify for the first time novel LOXL2 roles in tissue homeostasis and support it as a target for SCC therapy.     

The use of p63 as an effective immunomarker in the diagnosis of pulmonary squamous cell carcinomas on de-stained bronchial lavage cytological smears

M. Uke, B. Rekhi, D. Ajit and N. A. Jambhekar
The use of p63 as an effective immunomarker in the diagnosis of pulmonary squamous cell carcinomas on de‐stained bronchial lavage cytological smears Objectives: A diagnosis in pulmonary onco‐cytopathology primarily necessitates distinguishing small cell carcinoma (SCLC) from non‐small cell carcinoma (NSCLC), which includes squamous cell carcinoma and adenocarcinoma. Lately, p63 antibody has been used for distinguishing squamous cell carcinoma from SCLC and adenocarcinoma. We present an analysis of p63 expression in cytological smears from 100 bronchial lavage specimens comprising 51 cases of SCLC and 49 cases of NSCLC. Methods: A single Papanicolaou‐stained conventional smear was de‐stained and re‐fixed with cold acetone and methanol for immunocytochemical staining with p63 antibody. Staining results were graded as 0 (nil), 1+ (focal), 2+ (moderate, diffuse) and 3+ (strong, diffuse). Results: Out of 100 cases, 21 were cytologically diagnosed as squamous cell carcinoma. Twenty of these showed 2+ or 3+ p63 positivity, whereas one, which was adenocarcinoma on histology, showed 1+ staining. Of seven cases cytologically diagnosed as adenocarcinoma, six showed no p63 staining, whereas one, which was squamous cell carcinoma on histology, showed 1+ staining. All 48 cases cytologically diagnosed as SCLC were confirmed as such on histology and showed no p63 staining. Four cases were cytologically designated as poorly differentiated carcinomas, of which three showed no p63 staining and one showed 3+ staining. The former three were found to be SCLC on histology while the latter was squamous cell carcinoma. The remaining 20 cases were cytologically designated as NSCLC. Of these, eight showed no p63 staining, whereas 10 showed 1+ and two showed 2+ staining. The former eight were adenocarcinoma on histology and the latter two were squamous cell carcinoma. The 10 cases that showed 1+ p63 staining were adenocarcinomas (n = 5), squamous cell carcinoma (n = 4) and NSCLC, not otherwise specified (n = 1). Positive staining was seen in normal basal cells, which acted as an internal control. Overall sensitivity of p63 for squamous cell carcinoma was 100% and specificity was 90.4%. Conclusions: p63 immunostaining on processed cytology smears can be used to help identify squamous cell carcinoma. Its diffuse expression was specific for squamous cell carcinoma while focal staining was also seen in adenocarcinoma.     

Expression and function of interleukin-6 in epithelial cells

Epithelial cells both produce and are affected by interleukin-6 (IL-6). Experiments with an adenocarcinoma-derived cell line (HeLa) reveal that activation of the transfected human IL-6 promoter occurs largely through two partially overlapping second messenger (cAMP, phorbol ester)- and cytokine (IL-1, TNF, serum)-responsive enhancer elements (MRE 1, -173 to -151 and MRE II, -158 to -145). MRE I contains the typical GACGTCA cAMP and phorbol ester-responsive (CRE-TRE) motif, whereas MRE II defines a new CRE/TRE motif that contains an imperfect dyad repeat. The mechanism of dexamethasone-mediated repression of IL-6 gene expression in epithelial cells involves occlusion of the entire MRE enhancer region and of the core-promoter elements (TATA-box and RNA start site) by ligand-activated glucocorticoid receptor. Enhanced levels of IL-6 expression are observed in many solid tumors and in the hyperproliferative (and glucocorticoid-suppressible) lesions of psoriasis. In cell culture, IL-6 enhances, inhibits, or has no effect on the proliferation of epithelial cells depending upon the cell-type examined. IL-6 enhances proliferation of keratinocytes but inhibits that of breast carcinoma cell lines ZR-75-1 and T-47D. In these breast carcinoma cells, IL-6 elicits a major change in cell phenotype which is characterized by a fibroblastoid morphology, enhanced motility, increased cell-cell separation, and decreased adherens type junctions (desmosomes and focal adhesions). The new data identify IL-6 as a regulator of epithelial cell growth and of cell-cell association.     

CAIX furthers tumour progression in the hypoxic tumour microenvironment of esophageal carcinoma and is a possible therapeutic target

The hypoxic tumour microenvironment of solid tumours represents an important starting point for modulating progression and metastatic spread. Carbonic anhydrase IX (CAIX) is a known HIF-1α-dependent key player in maintaining cell pH conditions under hypoxia. We show that CAIX is strongly expressed in esophageal carcinoma tissues. We hypothesize that a moderate CAIX expression facilitates metastases and thereby worsens prognosis. Selective inhibition of CAIX by specific CAIX inhibitors and a CAIX knockdown effectively inhibit proliferation and migration in vitro. In the orthotopic esophageal carcinoma model, the humanized HER2 antibody trastuzumab down-regulates CAIX, possibly through CAIX’s linkage with HER2 in the hypoxic microenvironment. Our results show CAIX to be an essential part of the tumour microenvironment and a possible master regulator of tumour progression. This makes CAIX a highly effective and feasible therapeutic target for selective cancer treatment.