Oncofetal protein IMP3: a new diagnostic biomarker for laryngeal carcinoma

IGF2BPs as novel m6A readers: Diverse roles in regulating cancer cell biological functions, hypoxia adaptation, metabolism, and immunosuppressive tumor microenvironment

m6A methylation is the most frequent modification of mRNA in eukaryotes and plays a crucial role in cancer progression by regulating biological functions. Insulin-like growth factor 2 mRNA-binding proteins (IGF2BP) are newly identified m6A 'readers'. They belong to a family of RNA-binding proteins, which bind to the m6A sites on different RNA sequences and stabilize them to promote cancer progression. In this review, we summarize the mechanisms by which different upstream factors regulate IGF2BP in cancer. The current literature analyzed here reveals that the IGF2BP family proteins promote cancer cell proliferation, survival, and chemoresistance, inhibit apoptosis, and are also associated with cancer glycolysis, angiogenesis, and the immune response in the tumor microenvironment. Therefore, with the discovery of their role as 'readers' of m6A and the characteristic re-expression of IGF2BPs in cancers, it is important to elucidate their mechanism of action in the immunosuppressive tumor microenvironment. We also describe in detail the regulatory and interaction network of the IGF2BP family in downstream target RNAs and discuss their potential clinical applications as diagnostic and prognostic markers, as well as recent advances in IGF2BP biology and associated therapeutic value.

Role of IGF2BPs in head and neck squamous cell carcinoma

IGF2BPs belongs to a family of conserved RNA-bound oncoembryonic proteins that play a crucial part in various aspects of cell function, such as cell migration, morphology, metabolism, proliferation and differentiation. Recent studies have shown that IGF2BPs play a role as a member of m6A reader. m6A is the most abundant modification in RNA epigenetics, which is closely related to a family of RNA-binding proteins. These proteins are fell into three categories—writers, readers and erasers. In the present study, IGF2BPs play an important role in tumor metabolism, especially in head and neck squamous cell carcinoma (HNSCC) metabolism. In this paper, the basic structure of IGF2BPs, its role in the development of HNSCC, molecular mechanism, research progress and research prospect of IGF2BPs in HNSCC are reviewed, which will providing new ideas for further study of IGF2BPs.

Immunohistochemical Study of IMP3 Expression in Laryngeal Squamous Cell Carcinoma

BACKGROUND: IMP3 is an RNA binding protein, which is strongly expressed in malignant tumors, promoting tumor cell proliferation. AIM: The aim of the study was to evaluate the expression of IMP3 in laryngeal squamous cell carcinoma (SCC) and to correlate the expression of IMP3 with available clinicopathological data. METHODS: Sixty one total laryngectomy and laryngoscopic biopsies; collected from the Pathology Department, Faculty of Medicine, Cairo University. Two slides were prepared from each paraffin embedded tumor block, one slide for Hematoxylin and Eosin staining, and the other for immunohistochemical staining by IMP3 polyclonal antibody. RESULTS: Thirty-seven cases (60.7%) showed positive IMP3 expression, and a statistically significant correlation was found between IMP3 expressions in normal, dysplastic epithelium/in situ component, and the invasive malignant tumor tissue. Correlations between IMP3 expression and other available clinicopathological data were all non-significant. CONCLUSION: This study suggests that IMP3 might play a role in laryngeal SCC carcinogenesis and progression process from normal to dysplastic to malignant epithelium, and thus IMP3 might be targeted by gene therapy.

IMP3 Protein Overexpression Is Linked to Unfavorable Outcome in Laryngeal Squamous Cell Carcinoma

Simple Summary

IMP3 expression was analyzed in patients with malignant (laryngeal squamous cell carcinoma), semi-malignant (dysplasia) and benign (nodules, polyps) laryngeal lesions and correlated with clinical characteristics. Higher IMP3 stains were particularly found in malignant laryngeal pathologies, which might be useful for differentiation between premalignant and malignant lesions. In laryngeal cancer patients, higher IMP3 expression was associated with positive neck nodes and worse disease-specific survival.

Abstract

Background: The aim of this study was to (i) determine IMP3 protein expression in benign and malignant laryngeal lesions, (ii) compare its expression to Ki-67, p53, cyclin D1, and (iii) finally, to examine the prognostic power of IMP3 in squamous cell carcinomas of the larynx (LSSC). Methods: IMP3 protein expression was evaluated in 145 patients, including 62 LSCC, 45 dysplasia (25 with low and 20 with high-grade dysplasia), and 38 benign lesions (vocal cord polyps and nodules). Results: IMP3 was significantly higher expressed in LSCC compared to dysplasia and benign lesions (p < 0.001; p < 0.001, respectively). Similarly, higher expression patterns were observed for Ki-67 and p53, whereas cyclin D1 was equally distributed in all three lesions. IMP3 (p = 0.04) and Ki-67 (p = 0.02) expressions were significantly linked to neck node positivity, and IMP3 overexpression to worse disease-specific survival (p = 0.027). Conclusion: Since IMP3 showed significantly higher expression in laryngeal carcinomas, but not in high- or low-grade dysplasia, it serves as a useful marker to differentiate between invasive and noninvasive lesions. Higher IMP3 expression represented a significantly worse prognosticator for clinical outcomes of patients with squamous cell carcinoma of the larynx.

IMP3 Immunohistochemical Expression in Inverted Papilloma and Inverted Papilloma-Associated Sinonasal Squamous Cell Carcinoma

Sinonasal inverted papilloma (IP) has a propensity for malignant transformation. Although the IP-associated squamous cell carcinoma (SCC) is rare, it has a poor prognosis. To the best of our knowledge, this is the first study to assess IMP3 immunohistochemical (IHC) expression in sinonasal tumors and to compare it to the Ki-67 IHC expression and to other established clinicopathological parameters. A retrospective study was conducted on three groups which consisted of 72 cases of sinonasal IP, 20 age-matched samples of normal respiratory epithelium, and 15 cases of sinonasal SCC associated with IP, which were obtained from the archives of the Pathology Lab of Ain Shams University Specialized and Ain Shams University Hospitals during the period from January 2012 to December 2019. An IHC study was performed to evaluate IMP3 and Ki-67 expression in the three groups, with correlation of IMP3 expression to established clinicopathological parameters of sinonasal SCC on top of IP. Both IMP3 and Ki-67 showed a sharp rise in expression in the sinonasal SCC group. In addition, there were statistically significant differences in expression values between the 3 groups (P = 0.001). Receiver Operating Characteristic (ROC) analysis revealed that IMP3 and Ki-67 could be used to discriminate sinonasal SCC from control and IP lesions, with sensitivity and specificity of 100% and 81.5% for IMP3, respectively, and 100% and 62.5% for Ki-67, respectively. Spearman's rho revealed that both IMP3 and Ki-67 were significantly related to the lymph node and tumor stages but not to the tumor grade. ROC analysis was performed to select cut-off scores for progression and survival for IMP3, and accordingly, Kaplan-Meier analysis showed correlation between IMP3 and overall survival, local recurrence-free survival, and metastasis-free survival in sinonasal SCC cases at the selected cut-off values. Based on our results, IMP3 could serve as a promising diagnostic, prognostic, and therapeutic marker for IP-associated sinonasal SCC.

The expression of ribonuclear protein IMP3 in laryngeal carcinogenesis

OBJECTIVE

The aim of the study was to investigate the expression of ribonuclear protein IMP3 in laryngeal carcinogenesis, together with other biomarkers of carcinogenesis (Ki-67, p53 and cyclin D1), and to evaluate their predictive values.

METHODS

The study included 153 patients divided into three groups: 68 operated for primary invasive laryngeal squamous cell carcinoma (LSCC); 41 with precancerous lesions of atypical and abnormal hyperplasia; 44 with hyperplastic laryngeal nodule without atypia. Tissue microarray technique was used for immunohistochemical analysis.

RESULTS

All markers showed statistically significant differences between the three groups. The percentage of IMP3 positive cells is statistically significantly higher in LSCC group in comparison to precancerosis and control group. The percentage of Ki-67 positive cells is statistically significantly higher in LSCC group in comparison to precancerosis and control group. The percentage of p53 positive cells in LSCC group is statistically significantly higher than the control group and higher, but not statistically significant, than the precancerosis group. The percentage of cyclin D1 positive cells is statistically significantly higher in LSCC group than in precancerosis group and higher, but not statistically significant, than in the control group. All analyzed markers have good predictive values (AUC > 0.6), but the percentage of IMP3 positive cells is the only statistically significant marker in predicting whether the patient has LSCC or not.

CONCLUSION

Expression of Ki-67 and pronouncedly IMP3 generally follow the same pattern where control and precancerosis are similar and LSCC significantly differs, as opposed to p53 and cyclin D1. IMP3 expression increase possibly has an important diagnostic, therapeutic (in terms of the need for additional therapy after surgery) and prognostic value. Further studies on the exact molecular mechanisms behind it are, of course, needed.

Uterine leiomyosarcoma: A review of the literature and update on management options

Uterine leiomyosarcoma is the most common type of uterine sarcoma. It is an extremely aggressive malignancy associated with a poor overall prognosis. Women affected may vary in age, but are most often diagnosed in their perimenopausal years. Presenting symptoms may be vague and mimic other benign uterine conditions. Preoperative diagnosis of leiomyosarcoma is difficult and often only made at time of surgical resection. These rare mesenchymal tumors are characterized by cytologic atypia, a high mitotic index, and tumor necrosis on histologic inspection. Management of early stage disease entails hysterectomy and complete surgical resection of gross tumor, though routine oophorectomy or lymph node dissection do not appear to confer much clinical benefit. Adjuvant therapy for early stage disease remains controversial as multiple clinical trials have failed to demonstrate benefit on overall survival. Recently, progress has been made in regards to therapy for advanced and recurrent disease. Novel chemotherapeutics, targeted therapies such as olaratumab and pazopanib, and new immunotherapies such as nivolumab and pembrolizumab have demonstrated promise in these previously difficult drug-resistant patients. In this article, we provide a detailed review of uterine leiomyosarcoma including epidemiology, clinical presentation, diagnosis, and pathologic characteristics. We then go on detail management strategies, including options for adjuvant therapy, and highlight new and developing regimens in the field.

IMP3 and p16 expression in squamous cell carcinoma of the head and neck: A comparative immunohistochemical analysis

Expression of p16 has been established as a good surrogate marker for high-risk human papillomavirus (HPV) infection in oropharyngeal squamous cell carcinoma (OPSCC) patients, and it has been associated with an improved prognosis, irrespective of the actual HPV status. Conversely, the human insulin-like growth factor II mRNA binding protein 3 (IMP3) has been related to aggressiveness in several types of tumors. The aim of the present study was to investigate and compare p16 and IMP3 as markers of favorable and unfavorable behavior, respectively, in head and neck SCC (HNSCC), with particular reference to the HPV status. Both markers were analyzed by immunohistochemical analysis of 156 HNSCC samples originating from the oropharynx (n=81), oral cavity (n=44), larynx (n=15), hypopharynx (n=10) and nasopharynx (n=6). The HPV status was examined in a randomly selected representative subcohort (n=38) using polymerase chain reaction. Of the 156 HNSCC samples, 81 (51.9%) and 54 (34.6%) were positive for IMP3 and p16, respectively. IMP3 expression (P=0.022), p16 expression (P<0.001) and the combination of these markers (P<0.001) were significantly associated with tumor site. In particular, 69/81 (85%) OPSCC samples were positive for either one or both markers compared with 36/75 (48%) SCC samples from other sites. p16 expression was significantly associated with HPV infection (P=0.017) and a trend towards a negative association between IMP3 expression and HPV infection was observed (P=0.053). The results of the present study suggested that IMP3 and p16 are more frequently expressed in OPSCC compared with other HNSCCs. The prognostic impact of IMP3 on OPSCC remains to be investigated in a larger series with an extended follow-up period.

Insulin-like Growth Factor II Messenger RNA-binding Protein 3 in Salivary Gland Tumors

Insulin-like growth factor II mRNA-binding protein 3 (IMP3) is strongly expressed in malignant tumors and has been associated with their aggressive behavior. The aim of this study was to evaluate the presence of IMP3 in a series of salivary gland tumors. The sample consisted of 9 pleomorphic adenomas (PA), 14 adenoid cystic carcinomas (ACC), and 13 mucoepidermoid carcinomas (MEC) that were investigated by immunohistochemical technique. All cases of PA and MEC were positive for IMP3 particularly in the cytoplasm. PA showed 4 cases as high expression and 6 as low expression. MEC showed 10 cases as low expression and 3 as high expression. For ACC, 4 cases were high expression, whereas 6 cases were low expression. No significant difference was observed between tumors (P>0.05, Fisher's test) when both scores of IMP3 were compared. This study showed that MEC seems to be more sensitive to IMP3 than ACC and provided an insight into this protein in salivary gland tumors. Furthermore, although IMP3 is not a specific diagnostic marker to distinguish the tumors studied, it seems to mediate cell adhesion and migration in these tumors. Further studies should be performed to better understand the IMP3 biology in salivary gland tumors.

The RNA binding protein IMP3 facilitates tumor immune escape by downregulating the stress-induced ligands ULPB2 and MICB

Expression of the stress-induced ligands MICA, MICB and ULBP 1–6 are up-regulated as a cellular response to DNA damage, excessive proliferation or viral infection; thereby, they enable recognition and annihilation by immune cells that express the powerful activating receptor NKG2D. This receptor is present not exclusively, but primarily on NK cells. Knowledge about the regulatory mechanisms controlling ULBP expression is still vague. In this study, we report a direct interaction of the oncogenic RNA binding protein (RBP) IMP3 with ULBP2 mRNA, leading to ULBP2 transcript destabilization and reduced ULBP2 surface expression in several human cell lines. We also discovered that IMP3 indirectly targets MICB with a mechanism functionally distinct from that of ULBP2. Importantly, IMP3-mediated regulation of stress-ligands leads to impaired NK cell recognition of transformed cells. Our findings shed new light on the regulation of NKG2D ligands and on the mechanism of action of a powerful oncogenic RBP, IMP3.

DOI:http://dx.doi.org/10.7554/eLife.13426.001

Tumor cells differ from healthy cells in many aspects. Importantly, tumor cells have the ability to divide and grow much faster than normal cells. To protect ourselves from full-grown cancers, our bodies have developed a surveillance system: when a tumor cell starts to divide without restraint, “stress-induced” proteins start to appear on its surface. These proteins help the immune system recognize abnormal or damaged cells, allowing the immune cells to eliminate the defective cells.

Despite this system of protection, a tumor cell sometimes manages to avoid having stress-induced proteins placed on its surface, allowing it to remain undetected by the immune system. By studying several different types of human cancer cells, Schmiedel et al. found that a protein called IMP3 is present in cancer cells but not in healthy cells. Further investigation revealed that IMP3 prevents the production of some stress-induced proteins and stops them moving to the cell surface.

Schmiedel et al. also show that the presence of the IMP3 protein in cancer cells causes nearby immune cells to become much less active. This suggests that developing drugs that block the activity of IMP3 could help the immune system to fight back and destroy cancer cells.

DOI:http://dx.doi.org/10.7554/eLife.13426.002

Identification of biomarkers with a tumor stage-dependent expression and exploration of the mechanism involved in laryngeal squamous cell carcinoma

The aim of this study was to identify biomarkers with a tumor stage-dependent expression manner and explore the regulatory mechanisms of laryngeal squamous cell carcinoma (LSCC) progression. Microarray data GSE59102 was used for differential analysis using a limma package. Enrichment analyses were performed for the differentially expressed genes (DEGs) between tumor tissues and normal tissues at different stages. A co-expressed network involving the overlapped DEGs in two stages was established based on Pearson's correlation coefficients. Furthermore, for the tumor stage‑dependent expressed DEGs, a protein‑protein interaction (PPI) network was constructed by mapping the genes using the STRING database. Transcription factors (TFs), oncogenes and tumor‑associated genes (TSGs) among the DEGs were predicted, following a search of the TRANSFAC, tumor-associated gene (TAG) and TSG databases. The CDT database was used to identify LSCC‑associated genes. In total, 696 DEGs from early stage and control samples and 622 DEGs from advanced sttage and control samples were selected, which were mainly enriched in the cell cycle pathway. In the co-expressed network, BUB1, TTK, E2F1 and CEP55 were prominent, with E2F1 being predicted as a TSG and CEP55 as an oncogene. The HOX family members were predicted as TFs. MMP1, MMP9, MMP3 and PLAU were the most evident nodes in the PPI network, where MMP3 was connected with MMP1. The ADH family was correlated with LSCC. Several biomarkers with tumor stage-dependent expression were identified including MMP1, MMP3, MMP9, PLAU and ADHs. Additionally, the dysregulated cell cycle pathway involving BUB1, TTK, E2F1 and CEP55, and the mediation of MMP1 by MMP3 as well as the predicted TF HOX, may all play significant roles in LSCC progression.

Significance of serum insulin-like growth factor Ⅱ mRNA binding protein 3 level in patients with hepatocellular carcinoma

AIM: To determine serum insulin-like growth factor Ⅱ mRNA binding protein 3 (IMP3) level in patients with hepatocellular carcinoma, and to assess its value in early diagnosis and evaluation of progression of hepatocellular carcinoma.

METHODS: One hundred and twenty patients who were diagnosed with hepatocellular carcinoma from December 2011 to November 2013 were selected and served as an observation group, and 30 healthy volunteers were used as a control group. According to the severity of the disease, the observation group was further divided into three subgroups: Ⅰ, Ⅱ and Ⅲ. RT-PCR was performed to detect IMP3 mRNA levels, and ELISA assays were used to measure serum IMP3 concentrations.

RESULTS: IMP3 mRNA level was significantly higher in subgroup Ⅰ than in the control group (t = 19.72, P = 0.000), in subgroup Ⅱ than in subgroup Ⅰ (t = 9.67, P = 0.000), and in subgroup Ⅲ than in subgroup Ⅱ (t = 23.34, P = 0.000). Mean serum IMP3 concentration was significantly higher in the observation group than in the control group (134.25 ng/mL ± 19.33 ng/mL vs 9.37 ng/mL ± 1.23 ng/mL, t = 70.22, P = 0.000), in subgroup Ⅰ (48.35 ng/mL± 12.03 ng/mL) than in the control group ( t = 19.84, P = 0.000), in subgroup Ⅱ (95.36 ng/mL ± 9.25 ng/mL) than in subgroup Ⅰ (t = 19.67, P = 0.000), and in subgroup Ⅲ (214.23 ng/mL ± 23.64 ng/mL) than in subgroup Ⅱ (t = 28.83, P = 0.000).

CONCLUSION: With the progression of hepatocellular carcinoma, serum IMP3 concentration increases significantly. Serum IMP3 detection has potential value in early diagnosis and evaluation of progression of hepatocellular carcinoma.

The role of the oncofetal IGF2 mRNA-binding protein 3 (IGF2BP3) in cancer

The post-transcriptional control of gene expression mediated by RNA-binding proteins (RBPs), long non-coding RNAs (lncRNAs) as well as miRNAs is essential to determine tumor cell fate and thus is a major determinant in cancerogenesis. The IGF2 mRNA binding protein family (IGF2BPs) comprises three RBPs. Two members of the family, IGF2BP1 and IGF2BP3, are bona fide oncofetal proteins, which are de novo synthesized in various human cancers. In vitro studies revealed that IGF2BPs serve as post-transcriptional fine-tuners modulating the expression of genes implicated in the control of tumor cell proliferation, survival, chemo-resistance and metastasis. Consistently, the expression of both IGF2BP family members was reported to correlate with an overall poor prognosis and metastasis in various human cancers. Due to the fact that most reports used a pan-IGF2BP antibody for studying IGF2BP expression in cancer, paralogue-specific functions can barely be evaluated at present. Nonetheless, the accordance of IGF2BPs' role in promoting an aggressive phenotype of tumor-derived cells in vitro and their upregulated expression in aggressive malignancies provides strong evidence that IGF2BPs are powerful post-transcriptional oncogenes enhancing tumor growth, drug-resistance and metastasis. This suggests IGF2BPs as powerful biomarkers and candidate targets for cancer therapy.