NOB1 in Non-small-cell Lung Cancer: Expression Profile and Clinical Significance

Pien Tze Huang Inhibits Proliferation of Colorectal Cancer Cells through Suppressing PNO1 Expression and Activating p53/p21 Signaling Pathway

OBJECTIVE

To explore the regulatory effect of Pien Tze Huang (PZH) on targeting partner of NOB1 (PNO1) and it's down-stream mediators in colorectal cancer (CRC) cells.

METHODS

Quantitative polymerase chain reaction was performed to determine mRNA levels of PNO1, TP53, and CDKN1A. Western blotting was performed to determine protein levels of PNO1, p53, and p21. HCT-8 cells were transduced with a lentivirus over-expressing PNO1. Colony formation assay was used to detect cell survival in PNO1 overexpression of HCT-8 cells after PZH treatment. Cell-cycle distribution, cell viability and cell apoptosis were performed to identify the effect of PNO1 overexpression on cell proliferation and apoptosis of HCT-8 cells after PZH treatment. Xenograft BALB/c nude mice bearing HCT116 cells transduced with sh-PNO1 or sh-Ctrl lentivirus were evaluated. Western blot assay was performed to detect PNO1, p53, p21 and PCNA expression in tumor sections. Terminal deoxynucleotidyl transferase dUTP nick end labling (TUNEL) assay was used to determine the apoptotic cells in tissues.

RESULTS

PZH treatment decreased cell viability, down-regulated PNO1 expression, and up-regulated p53 and p21 expressions in HCT-8 cells (P<0.05). PNO1 overexpression attenuated the effects of PZH treatment, including the expression of p53 and p21, cell growth, cell viability, cell cycle arrest and cell apoptosis in vitro (P<0.05). PNO1 knockdown eliminated the effects of PZH treatment on tumor growth, inhibiting cell proliferation inhibition and apoptosis induction in vivo (P<0.05). Similarly, PNO1 knockdown attenuated the effects of PZH treatment on the down-regulation of PNO1 and up-regulation of p53 and p21 in vivo (P<0.05).

CONCLUSION

The mechanism by which PZH induces its CRC anti-proliferative effect is at least in part by regulating the expression of PNO1 and its downstream targets p53 and p21.

NOB1: A Potential Biomarker or Target in Cancer

Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.

miR‑145 inhibits human non‑small-cell lung cancer growth by dual-targeting RIOK2 and NOB1

Non-small cell lung cancer (NSCLC) is a leading cause of cancer-associated mortality worldwide. Right open reading frame kinase 2 (RIOK2) and nin one binding protein (NOB1) are important accessory factors in ribosome assembly. In our previous study, RIOK2 and NOB1 were revealed to be highly expressed in NSCLC, and were associated with the clinicopathological characteristics of patients with NSCLC, i.e. TNM clinical stage, lymph node metastasis and differentiation. In addition, RIOK2 expression was correlated with NOB1. To further explore the mechanism and the RIOK2 and NOB1 signaling pathway, microRNA (miR) regulation was analyzed. The tumor suppressor miR‑145 has been reported to be lowly expressed in numerous types of human cancer; in the present study, the expression levels of miR‑145 were decreased in patients with NSCLC. Furthermore, RIOK2 and NOB1 were predicted to be the direct targets of miR‑145 using bioinformatics software; this was further validated using a dual luciferase reporter assay. In addition, the protein expression levels of RIOK2 and NOB1 were inhibited in response to miR‑145 overexpression, thus resulting in the suppression of cell viability, migration and invasion. These results suggested that RIOK2 and NOB1 may be potential targets in the treatment of NSCLC, and miR‑145 may be considered a therapeutic inhibitor of both genes.

Effects of NOB1 on the pathogenesis of osteosarcoma and its expression on the chemosensitivity to cisplatin

The effects of NIN1/RPN12 binding protein 1 homolog (NOB1) on the pathogenesis of osteosarcoma and its expression on the chemosensitivity to cisplatin were investigated. Seventy-four patients with osteosarcoma who received surgical resection in The Affiliated Hospital of Southwest Medical University (Sichuan, China) from September 2013 to September 2016 were enrolled in this study. The expression of NOB1 in cancer and cancer-adjacent tissues of patients was detected by reverse transcription-polymerase chain reaction, and the relationship between NOB1 expression and the pathogenesis of osteosarcoma was analyzed. The expression of NOB1 in osteosarcoma MG-63 cells was interfered with using small interfering ribonucleic acid (siRNA). Western blotting was used to detect the transfection efficiency and changes in apoptosis indicators. Cell Counting Kit-8 (CCK-8) assay was used to examine changes in the sensitivity of cells to cisplatin. The effect of NOB1 knockout on cell apoptosis was examined by flow cytometry. In patients with osteosarcoma, the level of NOB1 mRNA in cancer tissues was significantly higher than that in cancer-adjacent tissues (p<0.05), and the expression of NOB1 was correlated with Ennecking staging and tumor size (p<0.05). The expression level of the apoptotic indicator caspase-3 was activated after siRNA interfered with NOB1 expression, thus reducing the expression level of anti-apoptotic indicator B-cell lymphoma 2. CCK-8 results showed that the downregulation of NOB1 increased the sensitivity of MG-63 cells to cisplatin (p<0.05). In addition, flow cytometry showed that the downregulation of NOB1 significantly promoted the apoptosis of MG-63 cells. NOB1 is significantly upregulated in patients with osteosarcoma, thus reducing the curative effect of cisplatin chemotherapy, which indicates that the prognosis is poor.

Inhibition of NOB1 by microRNA-330-5p overexpression represses cell growth of non-small cell lung cancer

MicroRNAs (miRNAs) play critical roles in the development and progression of various cancers, including non-small-cell lung cancer (NSCLC). Studies have suggested that miR-330-5p is involved in the progression of several cancers. However, the role of miR-330-5p in NSCLC remains unclear. We investigated the effect on and mechanism of miR-330-5p in the progression of NSCLC. We found that miR-330-5p was significantly downregulated in NSCLC tissues and cell lines as detected by real-time quantitative polymerase chain reaction (RT-qPCR). The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), bromodeoxyuridine (BrdU), colony formation and cell cycle assays showed that overexpression of miR-330-5p markedly inhibited cell growth. Annexin V-FITC/PI and caspase-3 activity assays showed that overexpression of miR-330-5p significantly promoted cell apoptosis of NSCLC cells. Bioinformatics analysis and dual-luciferase reporter assays confirmed NIN/RPN12 binding protein 1 (NOB1) as a target gene of miR-330-5p. RT-qPCR and Western blot analysis showed that overexpression of miR-330-5p inhibited the expression of NOB1 as well as cyclin D1 and cyclin-dependent kinase 4 in NSCLC cells. Moreover, overexpression of NOB1 markedly reversed the miR‑330-5p-mediated inhibitory effect on NSCLC cell growth. Correlation analysis showed that miR‑330-5p expression was inversely correlated with NOB1 mRNA expression in NSCLC tissues. Taken together, our results indicate that miR-330-5p inhibits NSCLC cell growth through downregulation of NOB1 expression. Our study suggests that miR-330-5p may serve as a potential therapeutic target for the treatment of NSCLC.

High Expression of RIOK2 and NOB1 Predict Human Non-small Cell Lung Cancer Outcomes

Non-small cell lung cancer (NSCLC) is the leading cause of cancer-related mortality worldwide. However, there is a shortage of suitable diagnostic markers for early stages of NSCLC, and therapeutic targets are limited. Right open reading frame (Rio) kinase 2 (RIOK2) and Nin one binding (NOB1) protein are important accessory factors in ribosome assembly and are highly expressed in malignant tumours; moreover, they interact with each other. However, the RIOK2 expression profile and its clinical significance as well as NOB1's mechanism in NSCLC remain unknown. In this study, NSCLC cell lines and 15 NSCLC tumour tissues (paired with adjacent normal lung tissues) were collected for a real-time quantitative PCR (RT-qPCR) analysis. In addition, 153 NSCLC cases and 27 normal lung tissues were used in an immunohistochemical analysis to evaluate the RIOK2 and NOB1 expression profiles, their clinicopathological factors in NSCLC and their correlations with prognoses. RIOK2 and NOB1 were highly expressed in NSCLC cells and tissues, and their expression profiles were significantly associated with the Tumour Node Metastasis (TNM) clinical stage, lymph node metastasis, and differentiation. RIOK2 expression was correlated with NOB1. The results suggested that simultaneously determining the expression of RIOK2 and NOB1 will improve the diagnostic rate in early stages of NSCLC. Moreover, RIOK2 and NOB1 might be potential targets for NSCLC therapy.

NOB1 expression predicts early response to cisplatin-based chemotherapy in patients with advanced non-small cell lung cancer

BACKGROUND

The aim of this study was to investigate the predictive value of Nin one binding (NOB1) expression for response to cisplatin-based chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC).

METHODS

A total of 105 consecutive patients with advanced NSCLC were retrospectively investigated between January 2012 and June 2014. We used transbronchial biopsy to collect cancer tissue samples. Immunohistochemistry were used in the detection of NOB1 protein expression. We assessed the chemotherapy early response by response evaluation criteria in solid tumours (RECIST) Version 1.1 at the end of the second cycle of chemotherapy.

RESULTS

In the 105 transbronchial biopsy NSCLC specimens, 22 (21.0%) stained NOB1 - , 35 (33.3%) stained +, 31 (29.5%) stained ++ and 17 (16.2%) stained +++. The early response rate to chemotherapy was 59.0% in overall NSCLC. Early response to chemotherapy has no relationship with patients' age, gender, smoke status, performance status and chemotherapy regimens (P>0.05), but related with TMN stage, histopathological grade, as well as NOB1 expression (P < 0.05). In squamous cell carcinoma and non-squamous cell carcinoma, same results were found. Logistic regression analysis showed TMN stage, histopathological grade and NOB1 expression were independent prognosis factors for early response to cisplatin-based chemotherapy in patients with advanced NSCLC. After adjusted by TMN stage and histopathological grade, the OR for NOB1 expression was 1.429 (95% CI 1.115-1.743, P = 0.008) for early response to chemotherapy.

CONCLUSION

Our results suggest that enhanced expression of NOB1 related with poor early response to cisplatin-based chemotherapy in patients with advanced non-small cell lung cancer.

Establishment of a Novel Monoclonal Antibody L6 Specific to NOB1

NOB1, a transcription-associated protein, may play important roles in the development of many cancers. In this study, we have efficiently generated one monoclonal antibody (MAb) against NOB1. Enzyme-linked immunosorbent assay (ELISA) and western blot were used to screen the hybridomas. As a result, one MAb named L6 (IgG1) effective in detecting the recombinant and the cellular NOB1 protein was characterized. Using L6, NOB1 was found to be upregulated in gastric cancer cells and tissues compared with normal gastric epithelial cells and nonneoplastic tissues. The expression of NOB1 was also found to be higher in multidrug-resistant gastric cancer cells than that of sensitive cells. This novel MAb will be valuable for investigating the role of NOB1 in carcinogenesis and multidrug resistance of gastric cancer.

NOB1 silencing inhibits the growth and metastasis of laryngeal cancer cells through the regulation of JNK signaling pathway

Nin one binding protein (NOB1) plays important roles in the synthesis and degradation of proteins, thus having effects on the cellular process. In the present study, the expression level of NOB1 in laryngeal cancer patients was detected by quantitative PCR and western blotting, and the effect of NOB1 on growth and metastasis of laryngeal cancer cells was explored. Silence of NOB1 was found to inhibit the proliferation of laryngeal cancer cells, arrest cell cycle and induce cell apoptosis. NOB1 silence was also found to inhibit the migration and invasion of laryngeal cancer cells and to downregulate the protein levels of matrix metalloproteinases (MMPs)-2 and MMP-9. Further mechanism study revealed that the JNK signaling pathway was involved in the function of NOB1. Our present results suggest that NOB1 plays an oncogenic role in laryngeal cancer cells through the regulation of JNK signaling pathway, and lays a theoretical foundation for further exploration of NOB1.

MiR-192 suppresses the tumorigenicity of prostate cancer cells by targeting and inhibiting nin one binding protein

Nin one binding (NOB1) protein has been identified as an oncogene in various human cancers, including prostate cancer. MicroRNAs (miRs) have also been recognized as novel regulatory molecules of gene expression. The present study aimed to discover potential miRs that target NOB1 and regulate NOB1 expression in prostate cancer. miR-192, which is an important regulator of numerous cancers, was found to be significantly downregulated in prostate cancer cells. Moreover, we noted that miR-192 overexpression markedly inhibited the proliferation, colony‑forming ability, and migratory capacity of the prostate cancer cells. miR-192 overexpression also induced cell cycle arrest in the G1 phase, as shown by flow cytometry. Bioinformatics analysis results revealed that NOB1 was a possible candidate target gene of miR-192. This discovery was further verified through dual‑luciferase reporter assay, RT-qPCR, and western blot analysis. We suggest that miR-192 directly regulates the mRNA and protein expression of NOB1. Furthermore, miR-192 inhibited the expression of p38 mitogen-activated protein kinase. The results of our study indicated that miR-192 negatively regulated NOB1 expression and impaired the tumorigenicity of prostate cancer cells. Therefore, we suggest that targeting miR-192 and NOB1 is a novel strategy which will assist in the development of new therapeutics that will be used in the future to prevent and treat prostate cancer.

Downregulation of NOB1 inhibits proliferation and promotes apoptosis in human oral squamous cell carcinoma

NIN1/RPN12 binding protein 1 homolog (NOB1) facilitates the maturation of the 20S proteasome and is then degraded by 26S proteasome to complete 26S proteasome biogenesis. It also accompanies the pre-40S ribosomes during nuclear export and is cleaved at D-site of 20S pre-rRNA to form mature 18S rRNA in growing cells. NOB1 was reported to be involved in the development of several types of cancer. However, the role of NOB1 in oral squamous cell carcinoma (OSCC) has not been addressed. In the present study, the expression of NOB1 in 50 OSCC patients with different genders, ages, TNM and pathological grades was detected using immunohistochemistry and western blotting. A loss-of‑function study was carried out by the lentivirus‑mediated siRNA knockdown of NOB1 in the CAL27 and TCA-8113 OSCC cell lines. The results showed that, NOB1 expression increased with pathological grades. In the CAL27 and TCA-8113 cell lines, knockdown of NOB1 in OSCC cells decreased cell proliferation, colony formation, increased cell apoptosis and also induced cell cycle arrest in the S phase. The results suggested that NOB1 is important in OSCC development and serves as a candidate indicator of aggressiveness and a therapeutic target of OSCC.

Relationship between NOB1 expression and prognosis of resected non-small cell lung cancer

BACKGROUND

The aim of this study was to investigate the relationship between Nin one binding (NOB1) protein expression and prognosis for resected non-small cell lung cancer (NSCLC).

METHODS

A prospective cohort of 70 consecutive patients with resected NSCLC was studied in 2009. Immunohistochemistry was used in the detection of NOB1 protein expression. Prognosis outcomes included overall survival (OS) and progression-free survival (PFS). The log-rank test and Cox hazard model were used to estimate the relationship between NOB1 expression and prognosis.

RESULTS

In the 70 NSCLC tissue specimens, 14 (20%) stained -, 24 (34%) stained +, 21 (30%) stained ++ and 11 (16%) stained +++. The NOB1 high expression rate was 16%. NOB1 expression was significantly different between TMN stage (p=0.024) and lymph node metastasis (p=0.001), as well as histopathological grades (p=0.037). Median OS was 43 months (95% confidence interval [95% CI], 35-51 months), and median PFS was 37 months (95% CI, 25-49 months). OS and PFS were related to TMN stage and lymph node metastasis, as well as NOB1 expression (p&lt;0.05). After adjustment for TMN stage and lymph node metastasis, the hazard ratio (HR) for high NOB1 expression was 1.7 (95% CI, 1.1-3.0, p=0.027) for OS, and 1.8 (95% CI, 1.3-3.7, p=0.031) for PFS.

CONCLUSIONS

Our results suggest that enhanced expression of NOB1 is related to poor overall survival and progression-free survival in patients with resected NSCLC.

Evaluation of NIN/RPN12 binding protein inhibits proliferation and growth in human renal cancer cells

The targeted delivery of small interfering RNA (siRNA) to specific tumor tissues and tumor cells remains as one of the key challenges in the development of RNA interference as a therapeutic application. The ribosome assembly factor NIN/RPN12 binding protein (NOB1) has been suggested to be essential for processing of the 20S pre-rRNA to the mature 18S rRNA, and is also reported to participate in proteasome biogenesis. However, it is unclear whether NOB1 is involved in tumor cells growth. The aim of this study was to determine whether the suppression of lentivirus mediated NOB1 siRNA inhibits the growth of human clean cell carcinoma (ccRCC) cells, further focused on NOB1 as a possible therapeutic target for renal cell carcinoma treatment. NOB1 deletion that caused significant decline in cell proliferation was observed in both 786-O and ACHN cell lines as investigated by MTT assay. Further, the number and size of the colonies formed were also significantly reduced in the absence of NOB1. Moreover, NOB1 gene knockdown arrested the cell cycle and inhibited cell cycle-related protein expression. The Kaplan-Meier survival curves revealed that low NOB1 expression was associated with poor prognosis in ccRCC patients. Collectively, these results indicate that NOB1 plays an essential role in renal cell cancer cell proliferation, and its gene expression could be a therapeutic target.