Protumoral roles of melanoma inhibitory activity 2 in oral squamous cell carcinoma

A Novel pyroptosis-related signature for predicting prognosis and evaluating tumor immune microenvironment in ovarian cancer

Ovarian cancer (OV) is the most fatal gynecological malignant tumor worldwide, with high recurrence rates and great heterogeneity. Pyroptosis is a newly-acknowledged inflammatory form of cell death with an essential role in cancer progression, though studies focusing on prognostic patterns of pyroptosis in OV are still lacking. Our research filtered 106 potential pyroptosis-related genes (PRGs) among the 6406 differentially expressed genes (DEGs) between the 376 TCGA-OV samples and 180 normal controls. Through the LASSO-Cox analysis, the 6-gene prognostic signature, namely CITED2, EXOC6B, MIA2, NRAS, SETBP1, and TRPV46, was finally distinguished. Then, the K-M survival analysis and time-dependent ROC curves demonstrated the promising prognostic value of the 6-gene signature (p-value < 0.0001). Furthermore, based on the signature and corresponding clinical features, we constructed and validated a nomogram model for 1-year, 2-year, and 3-year OV survival, with reliable prognostic values in TCGA-OV (p-value < 0.001) and ICGC-OV cohort (p-value = 0.040). Pathway analysis enriched several critical pathways in cancer, refer to the pyroptosis-related signature, while the m6A analysis indicated greater m6A level in high-risk group. We assessed tumor immune microenvironment through the CIBERSORT algorithm, which demonstrated the upregulation of M1 Macrophages and activated DCs and high expression of key immune checkpoint molecules (CTLA4, PDCD1LG2, and HAVCR2) in high-risk group. Interestingly, the high-risk group exhibited poor sensitivity towards immunotherapy and better sensitivity towards chemotherapies, including Vinblastine, Docetaxel, and Sorafenib. Briefly, the pyroptosis-related signature was a promising tool to predict prognosis and evaluate immune responses, in order to assist decision-making for OV patients in the realm of precision medicine.

CircNRIP1 acts as a sponge of miR-1200 to suppress osteosarcoma progression via upregulation of MIA2

Circular RNAs (circRNAs), a class of non-coding RNAs, play an essential role in embryo development and carcinogenesis, circNRIP1 was recently identified to promote development of multiple human cancers. This study investigated the role of circNRIP1 in osteosarcoma (OS) cells and the potential mechanisms relating to the sponging miRNAs and their target genes. OS cell lines and normal human osteoblasts were grown for qRT-PCR analysis of circNRIP1 expression and functions of circNRIP1 expression in OS cell proliferation, migration, and invasion in vitro. Bioinformatics analysis was then performed to predict the sponge miRNA of circNRIP1 and the target gene, which was confirmed by using the dual-luciferase reporter assay. The in vivo functions of circNRIP1 was evaluated in OS cell xenograft models, while levels of relevant marker genes were examined using immunohistochemistry. CircNRIP1 was mainly localized in OS cell cytoplasm and significantly lower in OS cell lines than in normal human osteoblasts. CircNRIP1 overexpression significantly inhibited OS cell proliferation, migration, and invasion in vitro. miR-1200 was predicted as the sponge miRNA of circNRIP1 and directly interacted with circNRIP1 confirmed by the dual-luciferase reporter assay. Moreover, miR-1200 overexpression significantly alleviated the inhibitory effect of circNRIP1 on OS cells. A protein-coding gene MIA2 was identified as the miR-1200 targeting gene and reversely associated with miR-1200 expression in OS cells. Increase in MIA2 expression in a murine OS cell xenograft model was associated with circNRIP1 expression in inhibition of OS cell xenograft growth in vivo. These data support the circNRIP1 OS-suppressive role by sponge of miR-1200 expression and in turn to upregulate MIA2 expression.

Melanoma Inhibitory Activity and Melanoma Inhibitory Activity 2 as Novel Immunohistochemical Markers of Oral Epithelial Dysplasia

Oral potentially malignant disorders are associated with the development of oral squamous cell carcinoma (OSCC). Most OSCCs are diagnosed via histopathology as oral epithelial dysplasia (OED), but the histologic diagnostic criteria remain non-uniform. Accordingly, the establishment of a diagnostic marker to assist in diagnosis could contribute towards cancer prevention. Melanoma inhibitory activity (MIA) and MIA2 are involved in tumor growth, invasion, and lymph node metastasis in various malignancies. The purpose of this study was to clarify the usefulness of MIA and MIA2 as diagnostic markers of oral mucosal lesions. The expression of MIA and MIA2 was analyzed immunohistochemically in 100 specimens (10 specimens with normal oral mucosa (NOM) and 30 specimens each with low-grade epithelial dysplasia (LED), high-grade epithelial dysplasia (HED), and OSCC). Immunohistochemical results were evaluated based on the Allred scoring system. Cytoplasmic expression of MIA and MIA2 increased in the order of LED, HED, and OSCC. All NOM specimens were negative for cytoplasmic expression. Significant differences were observed between the groups (NOM vs. HED, p < 0.05, NOM vs. OSCC, p < 0.001). These results demonstrate that MIA and MIA2 are expressed in the oral mucosa within early neoplastic lesions and suggest that MIA and MIA2 are useful novel immunohistochemical markers for discriminating between normal tissue and OED.

Identification of oral squamous cell carcinoma markers MUC2 and SPRR1B downstream of TANGO

PURPOSE

Transport and Golgi organization protein 1 (TANGO) promotes angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). To elucidate the underlying mechanisms, this study aims to identify and characterize elements downstream of TANGO that mediate its involvement in OSCC.

METHODS

In this study, microarray analysis compared gene expression between control and TANGO-repressed HSC3 cells. Protein expression in 213 OSCC tissue samples was analyzed immunohistochemically.

RESULTS

TANGO repression decreased or increased expression of Mucin 20 (MUC20) and small proline-rich protein 1B (SPRR1B), respectively. MUC20 increased the growth and invasiveness of OSCC cells via altered matrix metalloproteinase (MMP)-2 and E-cadherin expression and c-met phosphorylation. MUC20 induced angiogenesis and lymphangiogenesis by activating vascular endothelial growth factors A and C. In well-differentiated OSCC, SPRR1B expression was high (P = 0.0091) and correlated with keratinization markers and promoted proliferation by inducing mitogen-activated protein kinase p38 phosphorylation. MUC20 expression correlated significantly with clinical stage (P = 0.0024), lymph node metastasis (P = 0.0036), and number of blood and lymph vessels (P < 0.0001). MUC20-expressing cases had a significantly worse prognosis than non-expressing cases (P < 0.0001).

CONCLUSION

MUC20 and SPRR1B located downstream of TANGO may be useful molecular markers for OSCC.

Mast cell chymase promotes angiogenesis and lymphangiogenesis mediated by activation of melanoma inhibitory activity gene family members in oral squamous cell carcinoma

Mast cells (MCs) are present in the tumor stroma, and MCs that express the mast cell‑specific proteases tryptase and chymase (MCTC) exhibit several tumor‑related functions. It was previously reported that melanoma inhibitory activity (MIA) gene family members, including MIA, MIA2, and transport and Golgi organization protein 1 (TANGO), possess oncogenic functions in oral squamous cell carcinoma (OSCC). However, the relationships between MCTC, and clinicopathological characteristics and activation of the MIA gene family in OSCC remain unknown. In the present study, the functional roles of MCTC in patients with OSCC were investigated using immunohistochemistry and reverse transcription‑quantitative PCR. In addition, the effects of extracellular chymase on oral cancer cells were examined. In patients with OSCC, MCTC density was significantly affected by tumor progression and nodal metastasis, and was correlated with vessel density. MCTC density was also correlated with MIA and MIA2 expression. In OSCC cells, extracellular chymase promoted the secretion of vascular endothelial growth factor family proteins, and the transmigration and adhesion of HSC3 cells to endothelial cells; knockdown of MIA, MIA2 and TANGO attenuated these effects. The present findings indicated that MCTC act as tumor‑progressive factors in OSCC via the activation and secretion of MIA and MIA2, and the induction of angiogenesis and lymphangiogenesis.

OTOR in breast carcinoma as a potent prognostic predictor correlates with cell proliferation, migration, and invasiveness

Otoraplin (OTOR), recognized as an important cochlear gene, has a predicted secretory signal peptide sequence and harbors a high degree of cross-species conservation. However, its role in tumor progression is relatively unclear, especially in breast carcinoma (BC). This study investigated the clinicopathological significance of OTOR in breast infiltrating ductal carcinoma (IDC) with high metastasis to uncover its biological function in BC. OTOR was highly overexpressed in BC tissues and cells compared with normal samples. OTOR overexpression was associated with certain clinicopathological characteristics and poorer prognosis (overall survival; OS) of patients with breast IDC. As determined using CCK-8, colony formation, wound-healing, and Transwell assays, silencing OTOR using siRNA impeded BC-cell proliferation, migration, and invasiveness, which may have resulted from inactivating the mitogen-activated protein kinase - extracellular-signal-regulated kinase pathway. These results indicate that OTOR plays a crucial role in the progression of and prognosis for BC, which could help to identify future therapeutic targets for treating BC patients.

The Multifarious Functions of Pyruvate Kinase M2 in Oral Cancer Cells

Head and neck cancers, including oral squamous cell carcinoma (OSCC), are the sixth most common malignancies worldwide. OSCC frequently leads to oral dysfunction, which worsens a patient’s quality of life. Moreover, its prognosis remains poor. Unlike normal cells, tumor cells preferentially metabolize glucose by aerobic glycolysis. Pyruvate kinase (PK) catalyzes the final step in glycolysis, and the transition from PKM1 to PKM2 is observed in many cancer cells. However, little is known about PKM expression and function in OSCC. In this study, we investigated the expression of PKM in OSCC specimens and performed a functional analysis of human OSCC cells. We found that the PKM2/PKM1 ratio was higher in OSCC cells than in adjacent normal mucosal cells and in samples obtained from dysplasia patients. Furthermore, PKM2 expression was strongly correlated with OSCC tumor progression on immunohistochemistry. PKM2 expression was higher during cell growth, invasion, and apoptosis in HSC3 cells, which show a high energy flow and whose metabolism depends on aerobic glycolysis and oxidative phosphorylation. PKM2 expression was also associated with the production of reactive oxygen species (ROS) and integration of glutamine into lactate. Our results suggested that PKM2 has a variety of tumor progressive functions in OSCC cells.

Antimetastatic effects of Eclipta prostrata extract on oral cancer cells

Eclipta prostrata, a traditional Chinese medication, has been used for the treatment of several diseases. However, the molecular mechanism underlying the effects of Eclipta prostrata extracts (EPE) on human oral cancer cell metastasis remains unclear. We thus examined the effects of EPE on metastasis promoting proteins in oral cancer. Our results revealed that the EPE attenuated SCC-9, HSC-3, and TW2.6 cell migration and invasiveness by reducing matrix metalloproteinase (MMP)-2 enzyme activities. In addition, Western blot analysis revealed that EPE significantly reduced the levels of phosphorylated extracellular signal-regulated kinase 1/2 (ERK 1/2) but not those of c-Jun N-terminal kinase (JNK) 1/2 and p38. In conclusion, we found that EPE could inhibit oral cancer metastasis through the inhibition of MMP-2 expression. Therefore, EPE may be used to prevent the metastasis of oral cancer, and has the potential to be applied to cancer treatment.

Hallmarks of Cancer-Related Newly Prognostic Factors of Oral Squamous Cell Carcinoma

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth leading malignancy worldwide. OSCC is an aggressive tumor and its prognosis has exhibited little improvement in the last three decades. Comprehensive elucidation of OSCC's molecular mechanism is imperative for early detection and treatment, improving patient survival. Based on broadly accepted notions, OSCC arises from multiple genetic alterations caused by chronic exposure to carcinogens. In 2011, research revealed 10 key alterations fundamental to cancer cell development: sustaining proliferative signaling, evading growth suppressors, avoiding immune destruction, activating invasion and metastasis, tumor-promoting inflammation, enabling replicative immortality, inducing angiogenesis, genome instability and mutation, resisting cell death, and deregulating energetics. This review describes molecular pathological findings on conventional and novel hallmarks of OSCC prognostic factors. In addition, the review summarizes the functions and roles of several molecules as novel OSCC prognosticators.

The importance of melanoma inhibitory activity gene family in the tumor progression of oral cancer

Oral squamous cell carcinoma has a high potential for locoregional invasion and nodal metastasis. Consequently, early detection of such malignancies is of immense importance. The melanoma inhibitory activity (MIA) gene family comprises MIA, MIA2, transport and Golgi organization protein 1 (TANGO), and otoraplin (OTOR). These members of the MIA gene family have a highly conserved Src homology 3 (SH3)-like structure. Although the molecules of this family share 34-45% amino acid homology and 47-59% cDNA sequence homology, those members, excluding OTOR, play different tumor-associated functions. MIA has a pivotal role in the progression and metastasis of melanoma; MIA2 and TANGO have been suggested to possess tumor-suppressive functions; and OTOR is uniquely expressed in cochlea of the inner ear. Therefore, the definite functions of the MIA gene family in cancer cells remain unclear. Since the members of the MIA gene family are secreted proteins, these molecules might be useful tumor markers that can be detected in the body fluids, including serum and saliva. In this review, we described the molecular biological functions of the MIA gene family in oral cancer.

NIPA-like domain containing 1 is a novel tumor-promoting factor in oral squamous cell carcinoma

PURPOSE

In our previous global gene expression analysis, we identified NIPA-like domain containing 1 (NIPAL1), which encodes a magnesium transporter, as one of the most overexpressed genes in recurrent oral squamous cell carcinoma (OSCC). Although has been NIPAL1 linked with gout pathogenesis, little is known about its expression and function in human malignancies.

METHODS

In this study, we examined NIPAL1 expression in 192 cases of OSCC by immunohistochemistry and performed a functional analysis of human OSCC cells.

RESULTS

NIPAL1 immunostaining was observed in 39 of 192 OSCC patients (20.3%). NIPAL1 expression correlated significantly with cancer cell intravsation (P = 0.0062), as well as with poorer disease-free survival in a Kaplan-Meier analysis (P < 0.0001). Moreover, a multivariate Cox proportional hazards model analysis revealed that NIPAL1 expression was an independent predictor of disease-free survival in OSCC (P < 0.0001). In a functional analysis, NIPAL1 regulated the growth and adhesion of OSCC tumor cells and endothelial cells.

CONCLUSIONS

Our findings suggest that NIPAL1 might be a novel factor promoting OSCC tumorigenesis, as well as a useful molecular marker of OSCC.

A comprehensive expression analysis of the MIA gene family in malignancies: MIA gene family members are novel, useful markers of esophageal, lung, and cervical squamous cell carcinoma

Melanoma inhibitory activity (MIA) gene family members include MIA, MIA2, and Transport and Golgi organization protein 1 (TANGO). Although MIA gene family members have several tumor-related functions, their detailed roles in malignancies remain poorly elucidated. In this study, 477 tumor specimens were subjected to immunohistochemical screening to evaluate MIA gene family expression. For a validation analysis, we also examined the association between MIA gene family expression and clinicopathological factors in 66 cases of esophageal cancer, 145 cases of lung cancer, and 126 cases of cervical cancer. The frequency of MIA gene family expression was higher among squamous cell carcinomas than among other tumor types subjected to screening. In the validation analysis, MIA gene family staining was observed frequently in esophageal and lung cancers associated with nodal and/or distant metastasis. In cervical cancers, MIA and TANGO immunostaining also correlated with tumor progression and metastasis. Furthermore, MIA2 expression levels in invasive cervical cancer were upregulated relative to those in cervical intraepithelial neoplasia 3. A disease-free survival analysis revealed that MIA-, MIA2, or TANGO-positive patients had a significantly shorter disease-free survival than did those patients who were negative. Our results suggest that MIA, MIA2, and TANGO may be useful diagnostic and therapeutic molecular targets in human malignancies.

Storkhead box 2 and melanoma inhibitory activity promote oral squamous cell carcinoma progression

Background

Storkhead box protein 2 (STOX2) is a transcriptional factor associated with pre-eclampsia with fetal growth restriction. We recently reported that melanoma inhibitory activity (MIA) promotes oral squamous cell carcinoma (OSCC) progression. However, the relationship between STOX2 and MIA remains unknown in malignancies.

Methods

We used immunohistochemistry and PCR to investigate MIA and STOX2 expression in OSCC. We also performed functional analysis in human OSCC cells.

Results

MIA and STOX2 mRNA levels were higher in OSCCs than in normal oral epithelial cells, and upregulation of STOX2 was significantly correlated with overexpression of MIA. Immunostaining for STOX2 was associated with nodal metastasis (P = 0.0002) and MIA expression (P < 0.0001). Furthermore, MIA expression (P = 0.0035) and STOX2 expression (P = 0.0061) were associated with poor outcome in OSCCs. In vitro analysis using OSCC cells revealed that MIA increased expression of STOX2 by paracrine manner. Moreover, STOX2 accelerated OSCC cell growth, invasion, suppressed apoptosis, and enhanced resistance to paclitaxel, cisplatin, and 5-FU.

Conclusions

Our results suggest that MIA-STOX2 signaling may be a useful diagnostic and therapeutic target in OSCCs.

Molecular and functional analysis of anchorage independent, treatment-evasive neuroblastoma tumorspheres with enhanced malignant properties: A possible explanation for radio-therapy resistance

Despite significant advances in cancer treatment and management, more than 60% of patients with neuroblastoma present with very poor prognosis in the form of metastatic and aggressive disease. Solid tumors including neuroblastoma are thought to be heterogeneous with a sub-population of stem-like cells that are treatment-evasive with highly malignant characteristics. We previously identified a phenomenon of reversible adaptive plasticity (RAP) between anchorage dependent (AD) cells and anchorage independent (AI) tumorspheres in neuroblastoma cell cultures. To expand our molecular characterization of the AI tumorspheres, we sought to define the comprehensive proteomic profile of murine AD and AI neuroblastoma cells. The proteomic profiles of the two phenotypic cell populations were compared to each other to determine the differential protein expression and molecular pathways of interest. We report exclusive or significant up-regulation of tumorigenic pathways expressed by the AI tumorspheres compared to the AD cancer cells. These pathways govern metastatic potential, enhanced malignancy and epithelial to mesenchymal transition. Furthermore, radio-therapy induced significant up-regulation of specific tumorigenic and proliferative proteins, namely survivin, CDC2 and the enzyme Poly [ADP-ribose] polymerase 1. Bio-functional characteristics of the AI tumorspheres were resistant to sutent inhibition of receptor tyrosine kinases (RTKs) as well as to 2.5 Gy radio-therapy as assessed by cell survival, proliferation, apoptosis and migration. Interestingly, PDGF-BB stimulation of the PDGFRβ led to transactivation of EGFR and VEGFR in AI tumorspheres more potently than in AD cells. Sutent inhibition of PDGFRβ abrogated this transactivation in both cell types. In addition, 48 h sutent treatment significantly down-regulated the protein expression of PDGFRβ, MYCN, SOX2 and Survivin in the AI tumorspheres and inhibited tumorsphere self-renewal. Radio-sensitivity in AI tumorspheres was enhanced when sutent treatment was combined with survivin knock-down. We conclude that AI tumorspheres have a differential protein expression compared to AD cancer cells that contribute to their malignant phenotype and radio-resistance. Specific targeting of both cellular phenotypes is needed to improve outcomes in neuroblastoma patients.

Zinc finger AN1-type containing 4 is a novel marker for predicting metastasis and poor prognosis in oral squamous cell carcinoma

AIMS

Head and neck cancer, including oral squamous cell carcinoma (OSCC), is the sixth most common cancer worldwide and has a high potential for locoregional invasion and nodal metastasis. Therefore, discovery of a useful molecular biomarker capable of predicting tumour progression and metastasis of OSCC is crucial. We have previously reported zinc finger AN1-type containing 4 (ZFAND4) as one of the most upregulated genes in recurrent OSCC using a cDNA microarray analysis. Although ZFAND4 has been shown to promote cell proliferation of gastric cancer, its expression and clinicopathological roles in OSCC remain unclear.

METHODS

In this study, we examined ZFAND4 expression by immunohistochemistry in 214 cases of OSCC.

RESULTS

High cytoplasmic expression of ZFAND4 was observed in 45 out of 214 (21%) patients with OSCC. Expression levels of ZFAND4 were strongly associated with metastasis to the lymph nodes (p=0.0429) and distant organs (p=0.0068). Cases with high expression of ZFAND4 had a significantly unfavourable prognosis compared with patients with low expression of ZFAND4 (p<0.0001). Furthermore, ZFAND4 overexpression was an independent poor prognostic factor for OSCC as determined by multivariate analysis using the Cox proportional hazards model (p<0.0001).

CONCLUSIONS

These results suggest that ZFAND4 is a useful marker for predicting metastasis and poor prognosis in patients with OSCC.

Network-directed cis-mediator analysis of normal prostate tissue expression profiles reveals downstream regulatory associations of prostate cancer susceptibility loci

Large-scale genome-wide association studies have identified multiple single-nucleotide polymorphisms associated with risk of prostate cancer. Many of these genetic variants are presumed to be regulatory in nature; however, follow-up expression quantitative trait loci (eQTL) association studies have to-date been restricted largely to cis-acting associations due to study limitations. While trans-eQTL scans suffer from high testing dimensionality, recent evidence indicates most trans-eQTL associations are mediated by cis-regulated genes, such as transcription factors. Leveraging a data-driven gene co-expression network, we conducted a comprehensive cis-mediator analysis using RNA-Seq data from 471 normal prostate tissue samples to identify downstream regulatory associations of previously identified prostate cancer risk variants. We discovered multiple trans-eQTL associations that were significantly mediated by cis-regulated transcripts, four of which involved risk locus 17q12, proximal transcription factor HNF1B, and target trans-genes with known HNF response elements (MIA2, SRC, SEMA6A, KIF12). We additionally identified evidence of cis-acting down-regulation of MSMB via rs10993994 corresponding to reduced co-expression of NDRG1. The majority of these cis-mediator relationships demonstrated trans-eQTL replicability in 87 prostate tissue samples from the Gene-Tissue Expression Project. These findings provide further biological context to known risk loci and outline new hypotheses for investigation into the etiology of prostate cancer.

Role of JNK signaling in oral cancer: A mini review

JNKs (c-Jun N-terminal kinases) belong to mitogen-activated protein kinases' family and become activated by several growth factors, stress, radiation, and other extracellular signals. In turn, JNK activation results in phosphorylation of downstream molecules involved in many normal cellular processes. Nevertheless, recent data have linked JNK signaling with several pathological conditions, including neurodegenerative diseases, inflammation, and cancer. The role of JNK in cancer remains controversial. Initially, JNK was thought to play a rather oncosuppressive role by mediating apoptosis in response to stress stimuli, inflammatory, or oncogenic signals. However, a number of studies have implicated JNK in malignant transformation and tumor growth. The contradictory functions of JNK in cancer may be due to the diversity of JNK upstream and downstream signaling and are under intensive investigation. This review summarizes current literature focusing on the significance of JNK pathway in cancer development and progression, particularly addressing its role in oral cancer. Understanding the complexity of JNK signaling has the potential to elucidate important molecular aspects of oral cancer, possibly leading to development of novel and individualized therapeutic strategies.

Pancreatic adenocarcinoma up-regulated factor has oncogenic functions in oral squamous cell carcinoma

AIMS

Pancreatic adenocarcinoma up-regulated factor (PAUF) is a novel secretory protein which promotes tumour progression, metastasis and poor prognosis in pancreatic, cervical and colorectal carcinoma. It is also associated with gemcitabine resistance in pancreatic cancer cells. However, the expression and function of PAUF in oral squamous cell carcinoma (OSCC) remain unknown.

METHODS AND RESULTS

We performed an immunohistochemical analysis of PAUF in 222 clinicopathologically characterized cases of OSCC. We also investigated the growth, invasion, apoptosis induction and cisplatin resistance of OSCC cells under PAUF knockdown treatment. PAUF was localized in normal salivary glands. In OSCC, immunostaining for PAUF was found in 52 of 222 patients (23.4%), and correlated with nodal metastasis (P < 0.0001) and poor prognosis (P < 0.0001). Multivariate analysis using the Cox proportional hazards model identified that PAUF expression was an independent predictor of disease-free survival in OSCC (P < 0.0001). The down-regulation of PAUF in OSCC cells suppressed cell growth and invasion and induced apoptosis and cisplatin sensitivity.

CONCLUSIONS

Our results suggest that PAUF has tumour-promoting functions in OSCC. It may thus be a useful diagnostic and therapeutic marker for OSCC.

LEM domain containing 1 promotes oral squamous cell carcinoma invasion and endothelial transmigration

Background:

Oral squamous cell carcinomas have high potential for locoregional invasion and nodal metastasis. Thus, early detection and elucidation of detailed molecular mechanisms of OSCCs are important. Roles of LEM domain containing 1 (LEMD1), a novel cancer–testis antigen, in OSCCs are unclear.

Methods:

We performed immunohistochemical analysis of LEMD1 in 289 OSCC patients and examined functions of LEMD1 in these carcinomas.

Results:

Immunohistochemical analysis showed that 101 patients were positive for LEMD1. LEM domain containing 1 expression levels in OSCCs significantly correlated with tumour progression (T factor and clinical stage), nodal metastasis, and poor prognosis. LEM domain containing 1 expression was an independent predictor of disease-free survival in OSCC patients. In OSCCs, LEMD1 knockdown suppressed cancer cell invasion. Moreover, downregulation of LEMD1 expression inhibited adhesion and transmigration of OSCCs and vascular or lymphatic vascular endothelial cells.

Conclusions:

Our findings suggest that LEMD1 is a novel tumour progressive factor and may be a useful diagnostic and therapeutic target in OSCCs.

Mechanisms for exporting large-sized cargoes from the endoplasmic reticulum

Cargo proteins exported from the endoplasmic reticulum to the Golgi apparatus are typically transported in coat protein complex II (COPII)-coated vesicles of 60–90 nm diameter. Several cargo molecules including collagens and chylomicrons form structures that are too large to be accommodated by these vesicles, but their secretion still requires COPII proteins. Here, we first review recent progress on large cargo secretions derived especially from animal models and human diseases, which indicate the importance of COPII proteins. We then discuss the recent isolation of specialized factors that modulate the process of COPII-dependent cargo formation to facilitate the exit of large-sized cargoes from the endoplasmic reticulum. Based on these findings, we propose a model that describes the importance of the GTPase cycle for secretion of oversized cargoes. Next, we summarize reports that describe the structures of COPII proteins and how these results provide insight into the mechanism of assembly of the large cargo carriers. Finally, we discuss what issues remain to be solved in the future.