Over-expression of IQGAP1 indicates poor prognosis in head and neck squamous cell carcinoma

A Novel Disulfidptosis-Related Risk Signature for Prognostic Prediction in Patients With Ewing Sarcoma

Ewing sarcoma (ES) is a malignant bone tumor prevalent among children and adolescents. Disulfidptosis represents a novel form of cell death; however, the mechanism of disulfidptosis in ES remains unclear. Our aim is to explore the disulfidptosis-related prognostic signature in ES. Utilizing transcriptomic and clinical data of ES, disulfidptosis-related hub genes (DRHGs) were identified by differential gene expression analysis and Least Absolute Shrinkage and Selection Operator (LASSO) Cox regression analysis. A disulfidptosis-related risk score model (DRRS) was constructed based on these DRHGs. The performance of DRRS was assessed using survival analysis and receiver operating characteristic curve analysis. Immune cell infiltration in different risk subgroups and correlations between DRRS and antitumor reagents were also analyzed. In this study, we developed a disulfidptosis-related prognostic feature based on LRPPRC (leucine rich pentatricopeptide repeat containing), IQGAP1 (IQ motif containing GTPase activating protein 1), NDUFS1 (NADH:ubiquinone oxidoreductase core subunit S1), and TLN1 (talin 1), which may serve as a predictive and independent risk factor for ES. ES patients in the high-risk group exhibited a poorer prognosis, had a higher proportion of myeloid-derived suppressor cells (MDSCs) and M2 type of tumor-associated macrophages, and showed heightened sensitivity to some antitumor agents such as nilotinib and olaparib. This study is the first to construct a disulfidptosis-related prognostic signature that may predict the prognosis and immune response in ES patients, thereby providing a new reference for understanding the mechanisms of ES and guiding immunotherapy.

Pan-cancer and single-cell analysis of actin cytoskeleton genes related to disulfidptosis

Disulfidptosis was recently reported to be caused by abnormal disulfide accumulation in cells with high SLC7A11 levels subjected to glucose starvation, suggesting that targeting disulfidptosis was a potential strategy for cancer treatment. We analyzed the relationships between gene expression and mutations and prognoses of patients. In addition, the correlation between gene expression and immune cell infiltration was explored. The potential regulatory mechanisms of these genes were assessed by investigating their related signaling pathways involved in cancer, their expression patterns, and their cellular localization. Most cancer types showed a negative correlation between the gene-set variation analysis (GSVA) scores and infiltration of B cells and neutrophils, and a positive correlation between GSVA scores and infiltration of natural killer T and induced regulatory T cells. Single-cell analysis revealed that ACTB, DSTN, and MYL6 were highly expressed in different bladder urothelial carcinoma subtypes, but MYH10 showed a low expression. Immunofluorescence staining showed that actin cytoskeleton proteins were mainly localized in the actin filaments and plasma membrane. Notably, IQGAP1 was localized in the cell junctions. In conclusion, this study provided an overview of disulfidptosis-related actin cytoskeleton genes in pan-cancer. These genes were associated with the survival of patients and might be involved in cancer-related pathways.

LOXL2 serves as a prognostic biomarker for hepatocellular carcinoma by mediating immune infiltration and vasculogenic mimicry

BACKGROUND

The development of human hepatocellular carcinoma (HCC) is a multistep process that is accompanied by progressive changes in the liver microenvironment, including immune evasion and angiogenesis. Lysyl oxidase-like 2 (LOXL2) has been suggested to contribute to tumour progression and metastasis; however, the underlying mechanism remains unclear. The purpose of the present study was to explore the relationship between LOXL2 and immune infiltration and vasculogenic mimicry (VM) and to identify the role of LOXL2 in HCC diagnosis prognosis evaluation.

METHODS

The Cancer Genome Atlas (TCGA), UALCAN, GEPIA and Kaplan-Meier plotter databases were used to analyse LOXL2 expression and perform survival analysis. The Tumour Immune Estimation Resource (TIMER) was used to analyse immune cell infiltration, immune cell biomarkers and immune checkpoints. Immunohistochemistry (IHC) of 201 HCC samples was used to confirm the expression of LOXL2 and its relationship with VM. Coimmunoprecipitation (co-IP) and gain- and loss-of-function studies were performed to confirm the molecular mechanism of LOXL2 in VM.

RESULTS

The expression of LOXL2 in HCC was higher than that in normal tissues at both the mRNA and protein levels. High expression of LOXL2 was associated with a poorer prognosis of HCC. The genetic alteration rate of LOXL2 was 5%. LOXL2 was positively related to immune cell infiltration and immune checkpoints (PD-1 and CTLA-4) in HCC. Co-IP showed that LOXL2 can interact directly with IQGAP1. Both gain- and loss-of-function studies showed that LOXL2 significantly induced cell migration, invasion and VM formation when IQGAP1 was upregulated.

CONCLUSIONS

LOXL2 is involved in immune cell infiltration and promotes VM by upregulating IQGAP1. LOXL2 can be used as a novel biomarker for HCC diagnosis and prognosis prediction.

The Antithetic Roles of IQGAP2 and IQGAP3 in Cancers

The scaffold protein family of IQ motif-containing GTPase-activating proteins (IQGAP1, 2, and 3) share a high degree of homology and comprise six functional domains. IQGAPs bind and regulate the cytoskeleton, interact with MAP kinases and calmodulin, and have GTPase-related activity, as well as a RasGAP domain. Thus, IQGAPs regulate multiple cellular processes and pathways, affecting cell division, growth, cell-cell interactions, migration, and invasion. In the past decade, significant evidence on the function of IQGAPs in signal transduction during carcinogenesis has emerged. Compared with IQGAP1, IQGAP2 and IQGAP3 were less analyzed. In this review, we summarize the different signaling pathways affected by IQGAP2 and IQGAP3, and the antithetic roles of IQGAP2 and IQGAP3 in different types of cancer. IQGAP2 expression is reduced and plays a tumor suppressor role in most solid cancer types, while IQGAP3 is overexpressed and acts as an oncogene. In lymphoma, for example, IQGAPs have partially opposite functions. There is considerable evidence that IQGAPs regulate a multitude of pathways to modulate cancer processes and chemoresistance, but some questions, such as how they trigger this signaling, through which domains, and why they play opposite roles on the same pathways, are still unanswered.

IQGAP1 and RNA Splicing in the Context of Head and Neck via Phosphoproteomics

IQGAP1 (IQ motif-containing GTPase-activating protein 1) scaffolds several signaling pathways in mammalian cells that are implicated in carcinogenesis, including the RAS and PI3K pathways that involve multiple protein kinases. IQGAP1 has been shown to promote head and neck squamous cell carcinoma (HNSCC); however, the underlying mechanism(s) remains unclear. Here, we report a mass spectrometry-based analysis identifying differences in phosphorylation of cellular proteins in vivo and in vitro in the presence or absence of IQGAP1. By comparing the esophageal phosphoproteome profiles between Iqgap1+/+ and Iqgap1-/- mice, we identified RNA splicing as one of the most altered cellular processes. Serine/arginine-rich splicing factor 6 (SRSF6) was the protein with the most downregulated levels of phosphorylation in Iqgap1-/- tissue. We confirmed that the absence of IQGAP1 reduced SRSF6 phosphorylation both in vivo and in vitro. We then expanded our analysis to human normal oral keratinocytes. Again, we found factors involved in RNA splicing to be highly altered in the phosphoproteome profile upon genetic disruption of IQGAP1. Both the Clinical Proteomic Tumor Analysis Consortium (CPTAC) and the Cancer Genome Atlas (TCGA) data sets indicate that phosphorylation of splicing-related proteins is important in HNSCC prognosis. The Biological General Repository for Interaction Datasets (BioGRID) repository also suggested multiple interactions between IQGAP1 and splicing-related proteins. Based on these collective observations, we propose that IQGAP1 regulates the phosphorylation of splicing proteins, which potentially affects their splicing activities and, therefore, contributes to HNSCC. Raw data are available from the MassIVE database with identifier MSV000087770.

Role of IQGAP1 in Carcinogenesis

Scaffolding proteins can play important roles in cell signaling transduction. IQ motif-containing GTPase-activating protein 1 (IQGAP1) influences many cellular activities by scaffolding multiple key signaling pathways, including ones involved in carcinogenesis. Two decades of studies provide evidence that IQGAP1 plays an essential role in promoting cancer development. IQGAP1 is overexpressed in many types of cancer, and its overexpression in cancer is associated with lower survival of the cancer patient. Here, we provide a comprehensive review of the literature regarding the oncogenic roles of IQGAP1. We start by describing the major cancer-related signaling pathways scaffolded by IQGAP1 and their associated cellular activities. We then describe clinical and molecular evidence for the contribution of IQGAP1 in different types of cancers. In the end, we review recent evidence implicating IQGAP1 in tumor-related immune responses. Given the critical role of IQGAP1 in carcinoma development, anti-tumor therapies targeting IQGAP1 or its associated signaling pathways could be beneficial for patients with many types of cancer.

Role of IQGAP1 in Papillomavirus-Associated Head and Neck Tumorigenesis

Approximately 25% of head and neck squamous cell carcinomas (HNSCC) are associated with human papillomavirus (HPV) infection. In these cancers as well as in HPV-associated anogenital cancers, PI3K signaling is highly activated. We previously showed that IQ motif-containing GTPase activating protein 1 (IQGAP1), a PI3K pathway scaffolding protein, is overexpressed in and contributes to HNSCC and that blocking IQGAP1-mediated PI3K signaling reduces HPV-positive HNSCC cell survival and migration. In this study, we tested whether IQGAP1 promotes papillomavirus (PV)-associated HNSCCs. IQGAP1 was necessary for optimal PI3K signaling induced by HPV16 oncoproteins in transgenic mice and MmuPV1 infection, a mouse papillomavirus that causes HNSCC in mice. Furthermore, we found that, at 6 months post-infection, MmuPV1-infected Iqgap1-/- mice developed significantly less severe tumor phenotypes than MmuPV1-infected Iqgap1+/+ mice, indicating a role of IQGAP1 in MmuPV1-associated HNSCC. The tumors resulting from MmuPV1 infection showed features consistent with HPV infection and HPV-associated cancer. However, such IQGAP1-dependent effects on disease severity were not observed in an HPV16 transgenic mouse model for HNC. This may reflect that IQGAP1 plays a role in earlier stages of viral pathogenesis, or other activities of HPV16 oncogenes are more dominant in driving carcinogenesis than their influence on PI3K signaling.

Inhibition of SOCS6 confers radioresistance in esophageal squamous cell carcinoma

Esophageal cancer is one of the most common cancer of the digestive system and radiotherapy is widely applied in advanced esophageal cancer treatment, however radioresistance (RR) is one of the major reasons for radiotherapy failure. There is limited knowledge on the mechanisms that cause RR, here we identify suppressors of cytokine signaling 6 (SOCS6) is a negative regulator of radioresistance in ESCC cells. SOCS6 deficiency in ESCC cells conferred radioresistance in vitro and in vivo by increasing radiation-induced G2/M arrest, DNA damage repair and inhibiting radiation-induced apoptosis. Moreover, the transcriptome sequencing analysis demonstrates that the transcription of SOCS6 was partially p53-dependent. Importantly we found that highly correlated SOCS6 and P53 express lower in RR esophageal cancer tissues compare with radiosensitive ones. Collectedly our study uncovers that SOCS6, as a downstream effector of p53, is a key regulator involved in the radioresistance of ESCC.

The interplay between IQGAP1 and small GTPases in cancer metastasis

The metastatic spread of tumor cells to distant anatomical locations is a critical cause for disease progression and leads to more than 90 % of cancer-related deaths. IQ motif-containing GTPase-activating protein 1 (IQGAP1), a prominent regulator in the cancer metastasis process, is a scaffold protein that interacts with components of the cytoskeleton. As a critical node within the small GTPase network, IQGAP1 acts as a binding partner of several small GTPases, which in turn function as molecular switches to control most cellular processes, including cell migration and invasion. Given the significant interaction between IQGAP1 and small GTPases in cancer metastasis, we briefly elucidate the role of IQGAP1 in regulating cancer metastasis and the varied interactions existing between IQGAP1 and small GTPases. In addition, the potential regulators for IQGAP1 activity and its interaction with small GTPases are also incorporated in this review. Overall, we comprehensively summarize the role of IQGAP1 in cancer tumorigenicity and metastasis, which may be a potential anti-tumor target to restrain cancer progression.

Inhibition of cell proliferation and radioresistance by miR-383-5p through targeting RNA binding protein motif (RBM3) in nasopharyngeal carcinoma

Background

RNA binding protein motif (RBM3) is associated with radioresistance in nasopharyngeal carcinoma (NPC), and miR-383-5p was predicted to target the 3'-untranslated region (3'UTR) of RBM3 messenger RNA (mRNA). Our study aimed to investigate the role and the mechanisms of miR-383-5p targeting RBM3 in NPC cell proliferation and radioresistance (RR).

Methods

The expression of miR-383-5p was detected by Real-time quantitative PCR (qRT-PCR) between RS (Radiosensitivity) and RR (Radioresistance) NPC patient- tissue specimens and cell lines. Cell Counting Kit-8 (CCK-8) and Clonogenic survival assay were applied to analyze the effect of miR-383-5p on NPC cell proliferation and radioresistance. Possible downstream target of miR-383-5p in NPC cells, RBM3was evaluated by luciferase assay and qRT-PCR. miR-383-5p inhibited NPC cell proliferation and radioresistance through RBM3 by rescue experiments. The effect of miR-383-5p on radiation-induced apoptosis was explored through Flow cytometric analysis and Western blotting. Western blotting was analyzed the molecular of RBM3-mediated Jun N-terminal kinase (JNK) and extracellular signal-related kinase (ERK) signaling pathways

Results

The expression of miR-383-5p was decreased in radioresistant NPC tissues and cells. miR-383-5p inhibited cell proliferation and radioresistance in CNE1/IR cells. We also observed that therapeutic administration of a miR-383-5p agomir dramatically sensitized NPC xenografts to radiation in a mouse model. Conversely, in the same xenograft model, administration of a miR-383-5p antagomir dramatically increased NPC resistance to radiation. miR-383-5p targeted the 3'UTR of RBM3. miR-383-5p inhibited NPC cell proliferation and radioresistance through RBM3. Finally, we found that miR-383-5p increased radiation-induced apoptosis, activated JNK signaling, and inhibited ERK signaling.

Conclusions

Our study revealed that miR-383-5p targeted the 3'UTR of RBM3 and contributed to the efficacy of NPC radiation therapy by altering the RBM3-mediated JNK and ERK signaling pathways.

Increased Expression of SHMT2 Is Associated With Poor Prognosis and Advanced Pathological Grade in Oral Squamous Cell Carcinoma

This study focused on the expression of mitochondrial serine hydroxymethyltransferase (SHMT2) in oral squamous cell carcinoma (OSCC) and its correlation with clinical traits and the prognosis of OSCC patients. Immunochemical staining and Western blotting were used to quantify the expression of SHMT2 and related immune markers in OSCC. Using OSCC microarrays and The Cancer Genome Atlas (TCGA) database, we evaluated the association between SHMT2 and various clinical traits. We found that increased expression of SHMT2 was detected in OSCC and correlated with advanced pathological grade and recurrence of OSCC. By a multivariate Cox proportional hazard model, high expression of SHMT2 was shown to indicate a negative prognosis. In addition, in the OSCC microenvironment, increasing the expression of SHMT2 was associated with high expression levels of programmed cell death-ligand 1 (PD-L1), CKLF-like MARVEL transmembrane domain containing 6 (CMTM6), V-type immunoglobulin domain-containing suppressor (VISTA), B7-H4, Slug, and CD317. In the future, more effort will be required to investigate the role of SHMT2 in the OSCC microenvironment.

Integrative Analysis of the IQ Motif-Containing GTPase-Activating Protein Family Indicates That the IQGAP3-PIK3C2B Axis Promotes Invasion in Colon Cancer

Background

Colon cancer (CRC) is a common type of tumour, and IQGAP family proteins play an important role in many tumours. However, their roles in CRC remain unclear.

Methods

First, we searched many public databases to comprehensively analyze expression of IQGAPs in CRC. Next, real-time PCR, immunohistochemical (IHC), transwell, siRNA transfection and Western blot assays were used to evaluate relationships among IQGAP3 expression, clinical pathological parameters and CRC prognosis, and the underlying molecular mechanism was investigated.

Results

IQGAP3 was elevated in CRC tissues, whereas there was no significant change in expression of IQGAP1 or IQGAP2. Additionally, IQGAP3 expression in CRC tissues was associated with tumour progression, invasion and poor prognosis. In mechanistic studies, we found that IQGAP3 was positively coexpressed with PIK3C2B. In an in vitro assay, the PIK3C2B expression level was increased after exogenous overexpression of IQGAP3, resulting in the promotion of cell invasion, which was blocked by pretransfecting cells with PIK3C2B siRNA. Furthermore, we found that high expression of IQGAP3 and PIK3C2B correlated with tumour stage and vessel invasion in human CRC, whereby patients with high expression of both in tumours had a worse prognosis compared with patients with single-positive or double-negative tumours.

Conclusion

The results of our current study and corresponding previous studies provide evidence that IQGAP3 is elevated in CRC and promotes colon cancer growth and metastasis by regulating PIK3C2B activation.

Overexpression of PREX1 in oral squamous cell carcinoma indicates poor prognosis

Phosphatidylinositol 3,4,5-trisphosphate-dependent Rac exchanger (P-Rex) proteins control many fundamental cellular functions including cell migration, actin cytoskeletal rearrangement and adhesion in many cancers. However, P-Rex1 expression and its prognostic effect and possible clinical value are not clearly elucidated in human oral squamous cell carcinoma (OSCC). Here, OSCC tissue microarrays were used to verify the expression levels of P-Rex1, coinhibitory immune checkpoints and tumor associated macrophage (TAM) markers, and to analyze the relationship between PREX1 expression levels and clinicopathological characteristics in OSCC. The study found that P-Rex1 expression was elevated in OSCC compared to dysplasia and normal mucosa (P < 0.0001). In addition, patients who expressed high PREX1 had a poorer prognosis than those who expressed low PREX1 (P = 0.0070). Furthermore, positive correlations were found between P-Rex1 expression and the immune checkpoints PD-L1, Galectin-9 and B7-H4, and the TAM markers CD68, CD206 and CD163. In short, these findings implicated that overexpression of P-Rex1 may predict a poor prognosis in human OSCC.

A highway to carcinogenesis: the role of IQGAP1, a signaling scaffolding protein, in head and neck cancer development

Head and neck squamous cell carcinoma (HNSCC) is the sixth most frequent cancer worldwide. One of the most critical signaling pathways in HNSCC is the Epidermal Growth Factor Receptor/ Phosphatidylinositol 3-Kinase (EGFR/PI3K) pathway. IQ motif-containing GTPase- activating protein 1 (IQGAP1), a protein upregulated in multiple types of cancer, acts as a scaffold for this pathway and others implicated in cancer. IQGAP1 is overexpressed in HNSCCs, and its overexpression correlates with poorer prognosis in HNSCC patients, indicating that IQGAP1 might be important in HNSCC development. Here, we summarized our recent demonstrating a role of IQGAP1 in promoting HNSCC, at least in part, by scaffolding the EGFR/PI3K signaling pathway.

Genetic Profile and Functional Proteomics of Anal Squamous Cell Carcinoma: Proposal for a Molecular Classification

Anal squamous cell carcinoma is a rare tumor. Chemo-radiotherapy yields a 50% 3-year relapse-free survival rate in advanced anal cancer, so improved predictive markers and therapeutic options are needed. High-throughput proteomics and whole-exome sequencing were performed in 46 paraffin samples from anal squamous cell carcinoma patients. Hierarchical clustering was used to establish groups de novo Then, probabilistic graphical models were used to study the differences between groups of patients at the biological process level. A molecular classification into two groups of patients was established, one group with increased expression of proteins related to adhesion, T lymphocytes and glycolysis; and the other group with increased expression of proteins related to translation and ribosomes. The functional analysis by the probabilistic graphical model showed that these two groups presented differences in metabolism, mitochondria, translation, splicing and adhesion processes. Additionally, these groups showed different frequencies of genetic variants in some genes, such as ATM, SLFN11 and DST Finally, genetic and proteomic characteristics of these groups suggested the use of some possible targeted therapies, such as PARP inhibitors or immunotherapy.

Expression and clinicopathologic significance of coxsackie-adenovirus receptor in oral squamous cell carcinoma

OBJECTIVE

This study aimed to explore the relationship between the expression of the coxsackie-adenovirus receptor (CAR) in oral squamous cell carcinoma (OSCC) and the clinicopathologic parameters associated with the disease. The diagnostic and prognostic potential of CAR in OSCC was also investigated.

STUDY DESIGN

Immunohistochemistry was performed on human tissue microarrays, containing 42 oral mucosa, 69 dysplasia, and 176 OSCC tissue sections, to reveal the expression pattern of CAR. Statistical analysis was used to determine the correlation between CAR expression and the patient survival rate as a measure of the prognostic value of CAR.

RESULTS

CAR was overexpressed in human OSCC tissues (P = .002), and higher expression of CAR was associated with a lower survival rate, which was not statistically significant (P = .123). In addition, patients with OSCC in the human papillomavirus (HPV)-positive group showed significantly higher CAR expression compared with the HPV- negative group (P = .0491).

CONCLUSIONS

This study indicated that CAR expression was upregulated in human OSCC and that patients with OSCC with higher expression of CAR had a lower survival rate. Moreover, CAR expression may be associated with HPV infection.

A PI3K/AKT Scaffolding Protein, IQ Motif-Containing GTPase Associating Protein 1 (IQGAP1), Promotes Head and Neck Carcinogenesis

PURPOSE

Head and neck cancer (HNC) is the sixth most common cancer worldwide with a 5-year survival rate of less than 50%. The PI3K/AKT/mTOR signaling pathway is frequently implicated in HNC. Recently, IQ motif-containing GTPase-activating protein 1 (IQGAP1) was discovered to scaffold the PI3K/AKT signaling pathway. IQGAP1 gene expression is increased in HNC, raising the hypothesis that IQGAP1 contributes to HNC.

EXPERIMENTAL DESIGN

We performed a combination of in vitro studies using human cancer cell lines treated with a cell-permeable peptide that interferes with IQGAP1's ability to bind to PI3K, and in vivo studies utilizing mice genetically knocked out for the Iqgap1 (Iqgap1 ^-/-). In vivo EGF stimulation assays were used to evaluate PI3K signaling. To study the role of IQGAP1 in HNC, we used a well-validated mouse model that drives HNC via a synthetic oral carcinogen, 4-nitroquinoline 1-oxide (4NQO).

RESULTS

IQGAP1 is necessary for efficient PI3K signaling in vitro and in vivo. Disruption of IQGAP1-scaffolded PI3K/AKT signaling reduced HNC cell survival. Iqgap1 ^-/- mice had significantly lower cancer incidences, lesser disease severity, and fewer cancer foci. IQGAP1 protein levels were increased in HNC arising in Iqgap1^+/+ mice. The level of PI3K signaling in 4NQO-induced HNC arising in Iqgap1 ^-/- mice was significantly reduced, consistent with the hypothesis that IQGAP1 contributes to HNC at least partly through PI3K signaling. High IQGAP1 expression correlated with reduced survival, and high pS6 levels correlated with high IQGAP1 levels in patients with HNC.

CONCLUSIONS

These data demonstrate that IQGAP1 contributes to head and neck carcinogenesis.