Down-regulation of leucine-rich repeats and immunoglobulin-like domain proteins (LRIG1-3) in HP75 pituitary adenoma cell line

Prognostic significance of LRIG2 and LRIG3 proteins in urothelial bladder carcinoma

Bladder carcinoma is the second most frequent cancer in Egyptian males. Leucine-rich and immunoglobulin-like domains (LRIGs) are usually dysregulated in various human tumors. The aim of this study is to explore the immunohistochemical expression of LRIG2 and LRIG3 in urothelial bladder carcinoma (UBC) and their relationship to patients clinicopathological data including survival. The study cohort included 79 UBC cases (14 non muscle invasive (NMI) and 65 muscle invasive (MI)). We assessed the associations of LRIG2 and LRIG3 expression with clinicopathological data, as well as progression-free and overall survival. Most of studied cases (>50%) express LRIG2 and LRIG3. Statistically significant association was observed between positivity for LRIG3 and muscle invasion (P = 0.001), high grade (P = 0.03), and female gender (P = 0.02). Moreover, positive LRIG2 staining was associated with early stage (T2) (P = 0.03), lymphovascular invasion (P = 0.004), and tendency to non-muscle invasive stage (P = 0.07). Grouping of cases according to positivity/negativity of both markers showed that cases with dual positivity for both proteins are associated with muscle invasion (P = 0.001) and paradoxically with prolonged overall survival (P = 0.037). We conclude that although the association of LRIG3 with MI and high-grade tumors, its expression is related to better survival. LRIG3 has the dominant role even if it coexists with LRIG2. The role of LRIG2 remains to be further investigated.

Insights into pituitary tumorigenesis: from Sanger sequencing to next-generation sequencing and beyond

Introduction: This review explores insights provided by next-generation sequencing (NGS) of pituitary tumors and the clinical implications.Areas covered: Although syndromic forms account for just 5% of pituitary tumours, past Sanger sequencing studies pragmatically focused on them. These studies identified mutations in MEN1, CDKN1B, PRKAR1A, GNAS and SDHx causing Multiple Endocrine Neoplasia-1 (MEN1), MEN4, Carney Complex-1, McCune Albright Syndrome and 3P association syndromes, respectively. Furthermore, linkage analysis of single-nucleotide polymorphisms identified AIP mutations in 20% with familial isolated pituitary adenomas (FIPA). NGS has enabled further investigation of sporadic tumours. Thus, mutations of USP8 and CABLES1 were identified in corticotrophinomas, BRAF in papillary craniopharyngiomas and CTNNB1 in adamantinomatous craniopharyngiomas. NGS also revealed that pituitary tumours occur in the DICER1 syndrome, due to DICER1 mutations, and CDH23 mutations occur in FIPA. These discoveries revealed novel therapeutic targets and studies are underway of BRAF inhibitors for papillary craniopharyngiomas, and EGFR and USP8 inhibitors for corticotrophinomas.Expert opinion: It has become apparent that single-nucleotide variants and small insertion/deletion DNA mutations cannot explain all pituitary tumorigenesis. Integrated and improved analyses including whole-genome sequencing, copy number, and structural variation analyses, RNA sequencing and epigenomic analyses, with improved genomic technologies, are likely to further define the genomic landscape.

Over-expression of LRIG1 suppresses biological function of pituitary adenoma via attenuation of PI3K/AKT and Ras/Raf/ERK pathways in vivo and in vitro

Pituitary adenomas (PAs) are well known as a common intracranial benign tumor, and a portion of PAs are refractory to current therapeutic methods. ErbB receptors family signaling pathway regulates the expression of PAs activation associated gene. Inhibition of epidermal growth factor receptor (EGFR) can inhibit proliferation of PAs. Leucine-rich repeats and immunoglobulin-like domains protein 1 ( LRIG1), a negative mediated gene of ErbB receptors family, plays a role in many tumors. However, there are seldom researches about the functional role of LRIG1 in PAs. The aim of this study is to explore the potential effect of LRIG1 and its regulating mechanism in PAs. First, we investigated the role of LRIG1 in cell migration, invasion of PAs with transfected LRIG1 or control. Then, we explored its impact on cell proliferation and apoptosis of PAs in vivo. To study the regulating mechanism of LRIG1, we examined the expression of molecular factor of PI3K/AKT and Ras/Raf/ERK pathway using Western blotting in vitro and RT-PCR in vitro and in vivo. It was found that LRIG1 over-expression inhibited cell migration, invasion and proliferation, and promoted apoptosis of PAs in vivo and in vitro. Furthermore, LRIG1 suppressed the expression of signaling of PI3K/AKT and Ras/Raf/ERK pathways in PAs. LRIG1, as a negative mediated gene of tumor, can inhibit biological function of PAs via inhibiting PI3K/AKT and Ras/Raf/ERK pathways, and it might be a new target for gene therapy of PAs.

Expression of EGFR and LRIG proteins in oesophageal carcinoma with emphasis on patient survival and cellular chemosensitivity

BACKGROUND

Leucine-rich and immunoglobulin-like domains 1-3 (LRIG1-3) proteins have been implicated in the regulation of EGFR signalling. In the present study, we investigated the clinical implications of the expression of EGFR and LRIG1-3 in oesophageal carcinoma, as well as the correlation between their expression levels and the chemosensitivity of oesophageal carcinoma cell lines.

PATIENTS AND METHODS

Tumours from 80 patients with oesophageal carcinoma were investigated for the expression of EGFR and LRIG proteins by immunohistochemistry. Oesophageal carcinoma cell lines were investigated for their expression of EGFR and LRIG1, 2, and 3 by quantitative real time RT-PCR and for their sensitivity to commonly used chemotherapeutics by a cytotoxicity assay.

RESULTS AND DISCUSSION

Based on a total score of intensity and expression rates, a trend towards survival difference was found for EGFR (p = 0.09) and LRIG2 (p = 0.18) whereas for LRIG1 and -3 there was no trend towards any association with survival. Correlation analysis revealed a correlation with the clinical expression of EGFR and LRIG3 (p = 0.0007). Significant correlations were found between LRIG1 expression levels and sensitivity to cisplatin (r = -0.74), docetaxel (r = -0.69), and vinorelbine (r = -0.82) in oesophageal carcinoma cell lines. EGFR and the LRIG proteins may be functionally involved in oesophageal carcinoma, but larger materials are needed to fully elucidate the clinical implication.

Effect of over-expressed LRIG3 on cell cycle and survival of glioma cells

This study examined the effects of over-expression of leucine-rich repeats and immunoglobulin-like domains 3 (LRIG3) on the cell cycle and survival of human glioma cell line U87 and U251 and explored the possible mechanisms. The LRIG3 gene was transduced into U87 and U251 cells respectively by using lentivirus and the transduced cells were selected by puromycin. The changes in LRIG3 mRNA and protein levels were measured by RT-PCR and Western blotting. The apoptosis rate was detected by Annexin V-FITC/PI double labeling and the cell cycle was flow cytometrically analyzed. Compared with control cells, LRIG3 mRNA expression in U251 and U87 cells transduced with pLVX-DsRed-LRIG3-Monomer-N1 were increased by 77.6% and 129.7%, and LRIG3 protein expression was raised by 141.3% and 322.7%, respectively. Cell cycle analysis showed that LRIG3 over-expression increased the percentage of cells at G(0)/G(1) phase (P<0.01). Over-expressed LRIG3 could significantly promote the apoptosis of U87 and U251 cells (P<0.05). These findings suggest that the over-expression of LRIG3 could arrest the cell cycle in G(0)/G(1) phase, and promote apoptosis of U87 and U251 cells.

Association of expression of Leucine-rich repeats and immunoglobulin-like domains 2 gene with invasiveness of pituitary adenoma

The Leucine-rich repeats and immunoglobulin-like domains-2 (LRIG2) gene expression in pituitary adenoma and its correlation with tumor invasiveness were studied. The expression of LRIG2 mRNA and protein in human pituitary adenoma obtained surgically was detected by RT-PCR (39 cases) and immunohistochemical staining (30 cases). It was found that LRIG2 was mostly localized at the nucleus of the pituitary adenoma cells. Its expression was significantly higher in the invasive cases than in the non-invasive cases. LRIG2 protein was positive in 14 cases out of 21 cases of invasive adenoma, but only 2 cases were positive in 9 cases of non-invasive adenoma. The positive expression rate of LRIG2 mRNA was 91.3% in invasive cases (total 23 cases) and 62.5% in non-invasive cases (total 16 cases), respectively. LRIG2 gene is overexpressed in invasive pituitary adenoma. It may play an important role in pituitary adenoma invasiveness and further studies are necessary to elucidate the mechanism under this phenomenon.

Effect of silencing LRIG3 gene on the proliferation and apoptosis of bladder cancer T24 cells

This study examined the effect of silencing LRIG3 expression on the proliferation and apoptosis of bladder cancer T24 cells and explored the role of LRIG3 in the tumorigenesis of bladder cancer. Bladder cancer T24 cells were routinely cultured and pSilencer plasmids were employed to construct LRIG3 eukaryotic expression vector of LRIG3-siRNA, i.e., pSilencer-LRIG3-siRNA. After confirmation, the vector was transfected into HEK293 cells to make a replication-deficient adenovirus, pAd-LRIG3-siRNA, which was then introduced into bladder cancer T24 cells. RT-PCR, Western-blotting were performed to detect the levels of LRIG3 mRNA and proteins. Cells number was determined by using MTT test. Hoechst33258 staining, transmission microscopy, flow cytometery were conducted to examine the cell apoptosis. Three groups included a blank control group, a negative control group (containing non-interfering plasmids) and a pAd-LRIG3-siRNA group. Our results showed that the recombinant pAd-LRIG3-siRNA was successfully transfected into the bladder cancer T24 cells. The siRNA formed by the transcription of the recombinant plasmids resulted in significantly reduced expressions of LRIG3 gene and protein and significantly decreased cell proliferation and growth in the pAd-LRIG3-siRNA group as compared with the control group (P<0.01). The siRNA also caused apoptotic changes of some cells, with the apoptosis rate being (17.69±0.75)%, which was significantly different from that of the control group (P<0.01). It was concluded that recombinant pAd-LRIG3-siRNA plasmids could effectively decrease the expression of LRIG3 mRNA and proteins and, to some extent, inhibit the proliferation and promote the apoptosis of bladder cancer T24 cells. Silencing LRIG3 gene might be a novel alternative for the treatment of bladder cancer.

Effects of RNAi-mediated gene silencing of LRIG3 expression on cell cycle and survival of glioma cells

The effects of RNAi-mediated gene silencing of LRIG3 expression on cell cycle and survival of human glioma cell line GL15 and the possible mechanisms were explored. The plasmids pGenesil2-LRIG3-shRNA1 and pGenesil2-LRIG3-shRNA2 were transfected into GL15 glioma cells respectively by using Metafectine, and the transfected cells that stably suppressed LRIG3 expression were selected by G418. The control cells were transfected with negative control shRNA. The changes in LRIG3 mRNA and protein levels were measured by RT-PCR and Western blot. The apoptosis rate and cell cycle were analyzed by flow cytometry. As compared with the negative shRNA-transfected GL15 cells, LRIG3 mRNA expression in GL15 cells transfected with pGenesil2-LRIG3-shRNA1 and pGenesil2-LRIG3-shRNA2 was silenced by 52.4%, 63.8%, and LRIG3 protein expression was reduced by 50.9% and 67.4% respectively. The LRIG3-specific siRNA transfected cells had higher proliferation rate than control cells. Cell cycle analysis showed that silencing LRIG3 increased the percentage of G(2)/M phase cells and the proliferation index significantly (P<0.01). Silencing LRIG3 could inhibit the apoptosis of GL15 cells (P<0.05). These findings suggest that the siRNA targeting LRIG3 gene shows a dramatic inhibitory effect on RNA transcription and protein expression, then promoting the proliferation of GL15 cells, arresting GL15 cells in G(2)/M phase, and suppressing apoptosis of GL15 cells.