Isobaric Stable Isotope N-Phosphorylation Labeling (iSIPL) for Ultrasensitive Proteome Quantification

Stable isotope chemical labeling methods have been widely used for high-throughput mass spectrometry (MS)-based quantitative proteomics in biological and clinical applications. However, the existing methods are far from meeting the requirements for high sensitivity detection. In the present study, a novel isobaric stable isotope N-phosphorylation labeling (iSIPL) strategy was developed for quantitative proteome analysis. The tryptic peptides were selectively labeled with iSIPL tag to generate the novel reporter ions containing phosphoramidate P-N bond with high intensities under lower collision energies. iSIPL strategy are suitable for peptide sequencing and quantitative analysis with high sensitivity and accuracy even for samples of limited quantity. Furthermore, iSIPL coupled with affinity purification and mass spectrometry was applied to measure the dynamics of cyclin dependent kinase 9 (CDK9) interactomes during transactivation of the HIV-1 provirus. The interaction of CDK9 with PARP13 was found to significantly decrease during Tat-induced activation of HIV-1 gene transcription, suggesting the effectiveness of iSIPL strategy in dynamic analysis of protein-protein interaction in vivo. More than that, the proposed iSIPL strategy would facilitate large-scale accurate quantitative proteomics by increasing multiplexing capability.

Tear dynamics testing and quantitative proteomics analysis in patients with chronic renal failure

Ocular surface changes may develop in patients with chronic renal failure (CRF) undergoing hemodialysis. In recent years, an association of CRF with dry eye syndrome has been emphasized. However, tear proteomics of CRF patients has not been analyzed. Here, we performed systematic profiling of the tear film proteins in CRF patients through use of isobaric tags for relative and absolute quantitative (iTRAQ) MS/MS, aiming to identify associations between dry eye symptoms and expression of tear proteomic changes in patients with CRF undergoing hemodialysis. Twenty CRF patients and ten healthy subjects underwent a series of ophthalmic examinations. Tear samples from the participants were analyzed by iTRAQ approach. A total of 1139 tear proteins were screened, and 212 differentially expressed proteins were identified. The pattern changes included 77 whose expression levels were upregulated (fold increase >1.2) whereas 135 others that were downregulated (fold decrease <1/1.2). Bioinformatics analysis showed that these proteins were significantly enriched in lipid metabolism, inflammatory, and immune response pathways. Furthermore, APOA1, APOA4, APOB, APOE, S100A8, S100A9, S100A4, HSP90B and other molecules were significantly changed. Our study elucidated the characteristics of tear dynamics and protein markers in CRF patients undergoing hemodialysis. Significance: Despite the association of chronic renal failure (CRF) with dry eye disease, there are no reports describing potentially important differentially expressed tear proteins in CRF patients undergoing hemodialysis. It is still a challenge to obtain a comprehensive description of the pathogenesis of dry eye in CRF patients which hinders establishing a patient specific therapeutic scheme. Our study is the first iTRAQ proteomics analysis of the tears of patients with CRF, which reveals the changes in the protein expression profile in CRF patients afflicted with dry eye disease. The identity was verified of some relevant differentially expressed proteins, and they may be candidate diagnostic markers of dry eye disease in patients with CRF. These tear film protein constituents found in hemodialysis patients can be of important clinical significance in treating this condition. SIGNIFICANCE: Despite the association of chronic renal failure (CRF) with dry eye disease, there are no reports describing potentially important differentially expressed tear proteins in CRF patients undergoing hemodialysis. It is still a challenge to obtain a comprehensive description of the pathogenesis of dry eye in CRF patients which hinders establishing a patient specific therapeutic scheme. Our study is the first iTRAQ proteomics analysis of the tears of patients with CRF, which reveals the changes in the protein expression profile in CRF patients afflicted with dry eye disease. The identity was verified of some relevant differentially expressed proteins, and they may be candidate diagnostic markers of dry eye disease in patients with CRF. These tear film protein constituents found in hemodialysis patients can be of important clinical significance in treating this condition.

[Clinical application of enlarging greater ischiatic notch by ilium osteotomy to expose the sacral plexus via the gluteal approach]

Objectives: To observe the possibility of enlarging the greater sciatic notch by illium osteotomy through the posterior gluteal approach for reaching the intrapelvic upper sacral plexus as well as the covergence level of sacral plexus,and performing the nerve graft for surgical repairing the sacral plexus ruptured injuries or sacral plexus nerve tumor resection. Methods: The clinical data of 10 patients with sacral plexus injury or sacral plexus nerve tumor underwent the surgical operation via the expanded greater sciatic notch at Department of Hand Surgery,Beijing Jishuitan Hospital from July 2016 to November 2020 were retrospectively analyzed.There were 4 male and 6 female patients,with an age of (38.0±9.3)years (range:26 to 56 years).There were 8 cases with sacral plexus injury at the intrapelvic or covergence level (deep to the piriformis). Out of this 8 cases,4 cases with intrapelvic pan-sacral plexus injury,1 case with upper sacral plexus injury and 3 cases with convergence level pan sacral plexus injury.Another 2 cases were sacral plexus neoplasm.The average time from injury or onset to operation was 10.4 months (range:1.5 to 60.0 months). All cases were performed surgery for reaching the intrapelvic upper sacral plexus as well as the covergence level of sacral plexus with enlarging the greater sciatic notch by illium osteotomy through the posterior gluteal approach.Intraoperation the sacral plexus ruptured injurie was repaired and the sacral plexus nerve tumor was resected.Intraoperative findings,postoperative complications and healing of patients were recorded. Results: All the 10 patients underwent the sacral plexus surgical exploration and cutaneous nerve graft for sacral plexus nerve repairing or neurolysis or neoplasm resection through the posterior gluteal approach successfully.The length and width of illium osteotomy mass were (2.9±0.4)cm (range:2.5 to 3.8 cm) and (2.5±0.5)cm (range:1.5 to 3.4 cm) respectively.The median intraoperative bleeding volume was (M(QR))800(800)ml (range:400 to 2 000 ml).There were no complication with major vascular injury and hematoma formation,and all incisions healed.The postoperative follow-up was 29.8 months (range:1.5 to 54.0 months).Nine cases of iliac osteotomy were healed,and 1 case was not healed because the follow-up was only 1.5 months. Conclusions: The intrapelvic upper sacral plexus and the convergence level of sacral plexus deep to the piriformis can be exposed clearly through this posterior gluteal approach via illium osteotomy for enlarging the greater sciatic notch,and there was enough operative space that surgical exploration and nerve graft or nerve transfer or neoplasm resection can be performed.

Fibrin glue-assisted for the treatment of corneal perforations using glycerin-cryopreserved corneal tissue

AIM

To evaluate the outcomes and safety of lamellar keratoplasty (LK) assisted by fibrin glue in corneal perforations.

METHODS

Six eyes of 6 patients affected by different corneal pathologies (2 posttraumatic corneal scar and 3 bacterial keratitis) underwent LK procedures by using fibrin glue. The mean corneal perforation diameter was 1.35±0.64mm (range, 0.7-2.5mm), and the greatest diameter of the ulcerative stromal defect was 2.47±0.77mm in average (range, 1.5-3.5mm). The donor corneal lamella diameters were 0.20-mm larger and thicker than the recipient to restore a physiologic corneal thickness and shape: mean donor diameter was 8.34±0.28mm (range, 8.2-8.7mm) and mean thickness was 352±40.27mm (range, 220-400mm). Mean follow-up was 7.33±1.97 months (range, 6-11 months). Postoperatively, the graft status, graft clarity, anterior chamber response, the visual prognosis, intraocular pressures, and postoperative complications were recorded.

RESULTS

All the corneal perforations were successfully healed after the procedure. The best-corrected visual acuity (BCVA) ranged from 20/1 000 to 20/50 in their initial presentation, and from 20/100 to 20/20 in their last visit, showed increase in all the patients. No major complications such as graft dislocation and graft failure were noted. Neovascularization developed in the superficial stroma of donor graft in 1 case. High intraocular pressure developed on day 2 after surgery, while was remained in normal range after application of anti-glaucomatous eyedrops for 1 week in 1 case.

CONCLUSION

Fibrin glue-assisted sutureless LK is valuable for maintaining the ocular integrity in the treatment of corneal perforations.

Thrombin is a therapeutic target for metastatic osteopontin-positive hepatocellular carcinoma

We previously identified osteopontin (OPN) as a promoter and thus a potential therapeutic target for hepatocellular carcinoma (HCC) metastasis. The serine protease thrombin interacts with OPN and can modify its biological activity. To explore the role of thrombin alone or in conjunction with OPN in HCC, we studied the correlation of thrombin levels to HCC prognosis in patients with various OPN levels, and evaluated the effects of OPN fragments generated by thrombin cleavage on proliferation and adhesion of HCC cells. We found that the thrombin level was strongly associated with the metastatic potential of HCC cell lines, and that thrombin was remarkably overexpressed in HCC tissue compared with adjacent nontumor tissue. In addition, HCC tissue from patients with recurrent disease displayed much higher thrombin levels, particularly in those with elevated OPN levels. Only HCCs with elevated OPN levels had a significant correlation between high thrombin levels and overall survival (OS; P < 0.01), or time to recurrence (TTR; P < 0.0001) of HCC. Multivariate analysis revealed that thrombin was an independent prognostic indicator. In vitro assays demonstrated that thrombin promotes the proliferation and adhesion of OPN+ HCC cells. Furthermore, thrombin activated the focal adhesion kinase (FAK) pathway of OPN+ HCC cells, which was blocked by the inhibition of integrin β1.

CONCLUSION

Thrombin plays an important role in OPN-mediated aggressive phenotype of HCC through activation of integrin β1-FAK signaling, and is an independent poor prognostic factor for HCC. Thus, thrombin may be a potential therapeutic target to inhibit HCC metastasis in OPN+ patients.

Human mesenchymal stem cells inhibit metastasis of a hepatocellular carcinoma model using the MHCC97-H cell line

The effects of mesenchymal stem cells (MSC) on the growth and metastasis of human malignancies including hepatocellular carcinoma (HCC) are controversial, and the underlying mechanisms are not yet understood. The aim of this study was to explore the role of MSC in the progression of HCC. We investigated the effect of MSC on in vitro proliferation and invasion and in vivo tumor growth and pulmonary metastasis of MHCC97-H HCC cells with a high metastatic potential. The mRNA and protein levels of transforming growth factor-beta 1 (TGFβ1) and MMP, and their association with the effects of MSC on HCC cells were also evaluated. Co-culture of MHCC97-H cells with MSC conditioned medium significantly enhanced in vitro proliferation but inhibited invasiveness. Following MSC treatment of a nude mouse model bearing human HCC, the MSC were predominantly located in the HCC tissues. Compared with controls, MSC-treated mice exhibited significantly larger tumors (3080.51 ± 1234.78 mm(3) vs 2223.75 ± 1000.60 mm(3), P = 0.045), but decreased cellular numbers of lung metastases (49.75 ± 18.86 vs 227.22 ± 74.67, P = 0.046). Expression of TGFβ1 and MMP-2 was significantly downregulated in the MSC-treated HCC cells. TGFβ siRNA concurrently downregulated expression of TGFβ and MMP-2 in HCC cells and blocked the MSC-induced proliferation and invasiveness of MHCC97-H cells. The MSC enhanced tumor growth but significantly inhibited the invasiveness and metastasis of HCC, possibly through downregulation of TGFβ1. These findings suggest that MSC could be useful in controlling metastatic recurrence of HCC.

Abstract A16: Thrombin promotes hepatocellular carcinoma metastasis via mediating osteopontin-dependent tumor growth and adhesion activity

In our previous study, osteopontin (OPN) was identified as one of the leading genes that promote the metastasis of hepatocellular carcinoma (HCC), and a potential therapeutic target for HCC metastasis. The serine protease thrombin can interact with OPN and modify its biologic activity. To explore the role of thrombin alone or collaborating with OPN in HCC, we investigated the thrombin level and its correlation to the prognosis of 72 HCCs with different OPN backgrounds using real-time PCR and Western blot, and evaluated the effects of OPN fragments formed by thrombin cleavage on in vitro proliferation and adhesion of HCC cells. We found that the expression level of thrombin was positively related to the metastatic potentials of HCC cell lines, and was remarkably overexpressed in HCCs compared with the adjacent nontumor tissues. In addition, HCC tissues from patients with recurrent disease displayed much higher thrombin levels, particularly in those with OPN overexpressed. In the immunohistochemical study of 230 HCCs, only in those with a higher OPN level, a significant association was found between the higher thrombin level and the overall survival (OS; P &lt; 0.01) and time to recurrence (TTR; P &lt; 0.0001) of patients. Assays in vitro demonstrated that thrombin could promote the proliferation and adhesion of OPN+ HCC cells. And N-terminal of OPN showed better effects on the proliferation and adhesion abilities of HCC cells than the intact protein. Thrombin treatment could activate FAK pathway of OPN+ HCC cells, and this activation was blocked by the inhibition of integrin β1. Conclusions: Thrombin plays an important role in OPN-mediated aggressive phenotype and poor prognosis of HCC, which may be through the activation of the integrin β1 -FAK signaling. So, thrombin might be a potential therapeutic target to combat HCC progression in thrombin+/OPN+ patients.

Citation Information: Clin Cancer Res 2010;16(14 Suppl):A16.

Expression and prognostic significance of osteopontin and caspase-3 in hepatocellular carcinoma patients after curative resection

Osteopontin (OPN) plays an important role in the development, invasion, and metastasis of malignancies. Recently, several studies have reported that OPN enhances chemoresistance in small-cell lung cancer and breast cancer by blocking caspase-9 and caspase-3-dependent cell apoptosis. The aim of this study was to assess the value of OPN and caspase-3 for predicting tumor recurrence after curative resection in hepatocellular carcinoma (HCC) patients. We found that OPN expression increased concordantly with increasing metastatic potential in human HCC cell lines, whereas caspase-3 expression declined. In a tumor tissue microarray immunohistochemical analysis, we found that patients with higher levels of OPN and lower levels of caspase-3 had a significantly poorer prognosis than patients with lower OPN and higher caspase-3 levels. The combination of OPN and caspase-3 expression thus served as an effective prognosticator. These findings suggest that OPN alone or in combination with caspase-3 may act as an independent indicator for HCC patients after curative resection.

The diagnostic significance of carbohydrate antigen CA 19-9 in serum and pancreatic juice in pancreatic carcinoma

CA 19-9 is a carbohydrate antigen isolated from human colon carcinoma cell line, and is reportedly a tumor marker for pancreatic carcinoma. In this study we determined serum CA 19-9 in 71 normal subjects, 103 patients with benign digestive diseases, 85 patients with periampullary cancers, and 160 patients with other digestive cancers. Serum CA 19-9 was elevated only in 2.3% of normals and benign digestive disease patients, whereas it was increased in 72.7%, 86.4%, and 89.5% of pancreatic, ampullary, and choledochal carcinoma patients, respectively. Of other digestive cancer patients, it was elevated in 23.8%. In addition, very high serum CA 19-9 (greater than 120 u/m) was more often observed in patients with pancreatic, ampullary, and biliary cancer patients than in GL cancer patients (54.1% vs 9.4%, p less than 0.001). In 18 normal subjects and 68 patients with benign and malignant diseases, it was found that CA 19-9 content in the pancreatic juice was significantly increased in pancreatic, ampullary, and choledochal cancer patients, whereas in chronic pancreatitis patients it was normal, indicating that it is a specific and valuable tumor marker in differential diagnosis of pancreatic cancer.