Fengqing Hu

Overactivated Neddylation Pathway as a Therapeutic Target in Lung Cancer

BACKGROUND A number of oncoproteins and tumor suppressors are known to be neddylated, but whether the neddylation pathway is entirely activated in human cancer remains unexplored. METHODS NEDD8-activating enzyme (NAE) (E1) and NEDD8-conjugating enzyme (E2) expression and global-protein neddylation were examined by immunohistochemistry, immunoblotting, and real-time polymerase chain reaction analysis. Cell proliferation, clonogenic survival, migration, and motility in vitro, as well as tumor formation and metastasis in vivo, were determined upon neddylation inhibition by MLN4924, an investigational NEDD8-activating enzyme inhibitor. Survival was analyzed with Kaplan-Meier methods and compared by the log-rank test. All statistical tests were two-sided. RESULTS The entire neddylation pathway, including NEDD8-activating enzyme E1, NEDD8-conjugating enzyme E2, and global-protein neddylation, is overactivated in both lung adenocarcinoma and squamous-cell carcinoma. Compared with lung adenocarcinoma patients with low expression, those with high expression had worse overall survival (NEDD8-activating enzyme E1 subunit 1 [NAE1]: hazard ratio [HR] = 2.07, 95% confidence interval [CI] = 0.95 to 4.52, P = .07; ubiquitin-conjugating enzyme E2M (UBC12): HR = 13.26, 95% CI = 1.77 to 99.35, P = .01; global protein neddylation: HR = 3.74, 95% CI = 1.65 to 8.47, P = .002). Moreover, inhibition of neddylation by the NAE inhibitor MLN4924 statistically significantly suppressed proliferation, survival, migration, and motility of lung cancer cells in vitro and tumor formation and metastasis in vivo. At the molecular level, MLN4924 inactivated Cullin-RING E3 ligases, led to accumulation of tumor-suppressive Cullin-RING E3 ligase substrates and induced phorbol-12-myristate-13-acetate-induced protein 1 (NOXA)-dependent apoptosis or cellular senescence. CONCLUSIONS Our study highlights the overactivated neddylation pathway in lung cancer development and as a promising therapeutic target.

miR-342-3p targets RAP2B to suppress proliferation and invasion of non-small cell lung cancer cells.

MicroRNAs (miRNAs) play critical roles in cancer development and progression. In this study, we examined the roles and molecular mechanisms of miR-342-3p in human non-small cell lung cancer (NSCLC). The results showed that miR-342-3p is downregulated in NSCLC cell lines and tissues, and its overexpression induces significant inhibition of NSCLC cell proliferation, invasion, and tumor growth in nude mice. In addition, miR-342-3p repressed RAP2B expression through interactions with its 3′-UTR region. Restoration of RAP2B expression reversed miR-342-3p-mediated inhibitory activity in NSCLC cells. Finally, analyses of miR-342-3p and RAP2B levels in NSCLCs revealed that miR-342-3p inversely correlated with RAP2B mRNA expression. Our collective findings provide preliminary evidence that miR-342-3p acts as a tumor suppressor in NSCLC through repression of RAP2B.

USP22 promotes NSCLC tumorigenesis via MDMX up-regulation and subsequent p53 inhibition.

Increasing evidence suggests that ubiquitin-specific protease 22 (USP22) has great clinicopathologic significance in oncology. In this study, we investigated the role of USP22 in human NSCLC tumorigenesis along with the underlying mechanisms of action. First, we determined the expression of USP22 in human NSCLC, as well as normal tissues and cell lines. We then studied the effects of USP22 silencing by shRNA on NSCLC cell growth in vitro and tumorigenesis in vivo, along with the effect on the p53 pathway. We found that USP22 is overexpressed in human NSCLC tissues and cell lines. USP22 silencing by shRNA inhibits proliferation, induces apoptosis and arrests cells at the G0/G1 phases in NSCLC cells and curbs human NSCLC tumor growth in a mouse xenograft model. Additionally, USP22 silencing downregulates MDMX protein expression and activates the p53 pathway. Our co-immunoprecipitation analysis shows that USP22 interacts with MDMX in NSCLC cells. Furthermore, MDMX silencing leads to growth arrest and apoptosis in NSCLC cells, and over-expression of MDMX reverses the USP22 silencing-induced effects. Taken together, our results suggest that USP22 promotes NSCLC tumorigenesis in vitro and in vivo through MDMX upregulation and subsequent p53 inhibition. USP22 may represent a novel target for NSCLC treatment.

USP22 acts as an oncogene by regulating the stability of cyclooxygenase-2 in non-small cell lung cancer.

The histone ubiquitin hydrolase ubiquitin-specific protease 22 (USP22) is an epigenetic modifier and an oncogene that is upregulated in many types of cancer. In non-small cell lung cancer (NSCLC), aberrant expression of USP22 is a predictor of poor survival, as is high expression of cyclooxygenase-2 (COX-2). Despite its oncogenic role, few substrates of USP22 have been identified and its mechanism of action in cancer remains unclear. Here, we identified COX-2 as a direct substrate of USP22 and showed that its levels are modulated by USP22 mediated deubiquitination. Silencing of USP22 downregulated COX-2, decreased its half-life, and inhibited lung carcinoma cell proliferation by directly interacting with and modulating the stability and activity of COX-2 through the regulation of its ubiquitination status. The findings of the present study suggest a potential mechanism underlying the oncogenic role of USP22 mediated by the modulation of the stability and activity of COX-2.

Activated cdc42-associated kinase is up-regulated in non-small-cell lung cancer and necessary for FGFR-mediated AKT activation.

Activated cdc42‐associated tyrosine kinase 1 (ACK1) has been reported to be implicated in non‐small‐cell lung cancer (NSCLC). However, the expression pattern and biological functions of ACK1 in the progression of NSCLC are not fully understood. In this study, it was found that the expression of ACK1 was significantly up‐regulated in NSCLC samples compared to their adjacent normal tissues. Meanwhile, the expression of ACK1 was inversely correlated with the survival of NSCLC patients. Moreover, in the biological function studies, ACK1 was further validated to promote the growth, migration, and metastasis of NSCLC cells in vitro and in vivo. Mechanistically, ACK1 bind with FGFR1 and was essential for the phosphorylation of AKT induced by FGF. Our study demonstrated that ACK1 played an oncogenic role in the progression of NSCLC and ACK1 might be a promising target for the treatment of NSCLC.

TMEM45B, up-regulated in human lung cancer, enhances tumorigenicity of lung cancer cells.

Transmembrane protein 45B (TMEM45B) is a member of TMEMs. Altered expression of TMEMs is frequently observed in a variety of human cancers, but the expression and functional roles of TMEM45B in lung cancer is not reported. In the present study, levels of mRNA expression of TMEM45B in lung cancer tissues were assessed using re-analyzing expression data of The Cancer Genome Atlas (TCGA) lung cancer cohort and real-time PCR analysis on our own cohort. Lung cancer cells, A549 and NCI-H1975, infected with TMEM45B short hairpin RNA were examined in cell proliferation, cell cycle, cell apoptosis, wound-healing, and cell invasion assays as well as mouse xenograft models. Here, we demonstrated that TMEM45B was overexpressed in lung cancer and its expression correlated with overall survival of patients. In addition, silencing of TMEM45B expression reduced cell proliferation in vitro and in vivo, induced cell cycle arrest and cell apoptosis, and blocked cell migration and invasion. Moreover, knockdown of TMEM45B significantly suppressed G1/S transition, induced cell apoptosis, and inhibited cell invasion via regulating the expression of cell cycle-related proteins (CDK2, CDC25A, and PCNA), cell apoptosis-related proteins (Bcl2, Bax, and Cleaved Caspase 3), and metastasis-related proteins (MMP-9, Twist, and Snail), respectively. Thus, TMEM45B is a potential prognostic marker and cancer-selective therapeutic target in lung cancer.

A Novel Modified Nuss Procedure for Pectus Excavatum: A New Steel Bar

PURPOSE The purpose of this article is to introduce a new modified Nuss procedure for pectus excavatum and to describe the configuration of the new steel bar. DESCRIPTION We applied a novel method with a new steel bar for minimally invasive surgical correction of pectus excavatum. The procedure was performed with a new steel bar through bilateral thoracic minimally invasive incisions using a thoracoscope for guidance. The bar was installed or removed by pushing and pulling without turning it over. EVALUATION One hundred forty-seven patients with pectus excavatum underwent this novel modified Nuss procedure. All patients had a satisfactory orthopedic result at discharge. There was no perioperative death or cardiac perforation. During the follow-up period, 134 patients underwent bar removal. Of the 134 cases, the initial orthopedic and functional results were excellent in 121 patients (90.3%) and good in 13 patients (9.7%). No patient had recurrence. CONCLUSIONS This novel modified Nuss procedure is a safe, effective, and convenient treatment for pectus excavatum.

Pyruvate kinase M2 interacts with DNA damage-binding protein 2 and reduces cell survival upon UV irradiation

Pyruvate Kinase M2 (PKM2) is highly expressed in many solid tumors and associated with metabolism reprogramming and proliferation of tumors. Here, we report that PKM2 can bind to DNA Damage-Binding Protein 2 (DDB2), which is necessary for global nucleotide excision repair of UV induced DNA damage. The binding is promoted by UV irradiation and K433 acetylation of PKM2. Over expression of PKM2 facilitates phosphorylation of DDB2 and impairs DDB2-DDB1 binding. Furthermore, knocking down of PKM2 increases cell survival upon UV irradiation, while over expression of PKM2 reduces cell survival and over expression of DDB2-DDB1 reverts this effect. These results reveal a previously unknown regulation of PKM2 on DDB2 and provide a possible mechanism for UV induced tumorigenesis.