The E3 ubiquitin ligase Cbl-b inhibits tumor growth in multidrug-resistant gastric and breast cancer cells

Most receptor tyrosine kinases (RTKs) contribute to tumor growth, and their ubiquitination and degradation is related to the inhibition of tumor growth. Our previous study showed that the ubiquitin ligase Cbl-b was expressed at low levels in multidrug-resistant (MDR) gastric cancer cells compared with their parental cells. However, whether enhancement of Cbl-b expression in MDR cancer cells could prevent tumor proliferation via ubiquitination and degradation of RTK remains unclear. In the present study, Cbl-b overexpression reduced cell proliferation in MDR gastric and breast cancer cells, and effectively inhibited tumor growth in vivo. Additionally, Cbl-b overexpression reduced the total protein level of insulin-like growth factor 1 (IGF-1R), an important member of the RTK family. Moreover, Cbl-b overexpression promoted interaction of Cbl-b with IGF-1R, and induced ubiquitination and degradation of IGF-1R and inactivation of the IGF-1R pathway. These results suggest that the ubiquitin ligase Cbl-b inhibited tumor growth via ubiquitination and degradation of IGF-1R in MDR gastric and breast cancer cells.

[Effect of death decoy receptor 3 on prognosis of breast cancer and function of breast cancer cells in vitro]

Objective: To study the effect of death decoy receptor 3 on the prognosis of breast cancer and the invasive function of breast cancer cells in vitro. Methods: Expression of DcR3 were assessed qualitatively by Q-PCR to analyze the correlation in 115 mammary tissue samples with a 10-year median follow-up. The expression of DcR3 was examined in MCF7 and MDA-MB-231 cell lines using immunocytochemical staining and RT-PCR. DcR3 knock-down cell sub-lines were constructed. The effects of reduced DcR3 expression were observed by establishing invasion and migration models. Results: Patients were divided into the good prognosis group (n=81) and the poor prognosis group (n=26). The expression of DcR3 in the poor prognosis group (133 350+49 646 copies/50 ng RNA)was significantly higher than that in the good prognosis group (5 393+1 428 copies/50 ng RNA, P=0.020). DcR3 transcripts were found to be increased significantly in grade 2 cancers compared to well differentiated grade 1(82 844±34 068 copies/50 ng RNA, n=39,) vs (5 371±3 500 copies/50 ng RNA, n=20, P=0.029).The DcR3 gene of MCF7 cell line and MDA-MB-231 cell line were successfully knocked out and verified that DcR3 knockout. And the invasion and migration of MCF7 cells were inhibited (P=0.009, P=0.001). However, no significant difference was found in these two aspects of the MDA-MB-231 cell line (P=0.475, P=0.102). Conclusion: DcR3 promotes the capacity of invasion of breast cancer cells and plays an important role in the metastasis of breast cancer. DcR3 detection is helpful to the judgment about prognosis of breast cancer.

MiR-99a-5p regulates proliferation, migration and invasion abilities of human oral carcinoma cells by targeting NOX4

Previous research has showed that miR-99a-5p was a tumor suppressor. The aim of our study was to explore the effect of miR-99a-5p on the vitality and proliferation, migration together with the invasion of oral tumor cells via inhibiting the expression of NOX4. QRT-PCR and Western blot were applied to examine the expression level of miR-99a-5p and NOX4 in human oral tumorous and adjacent tissues. Dual luciferase reporter gene assay was applied to confirm that miR-99a-5p negatively regulated directly on NOX4 in TSCC1 cells. Cell transfection and lentiviral vectors were used to up-regulate expression of miR-99a-5p and NOX4, respectively. Cell proliferation, cell cycle, apoptosis and invasion along with the migration in different groups were assessed using MTT assay, colony formation assay, the flow cytometry, transwell assay and the wound healing assay, respectively. MiR-99a-5p was under-expressed in human oral tumor, while NOX4 was over-expressed. There was a negative relationship between miR-99a-5p and NOX4. Up-regulating miR-99a-5p or down-regulating NOX4 suppressed the vitality, proliferation, migration together with invasion of TSCC1 cells. MiR-99a-5p affected the vitality and proliferation, migration together with the invasion of oral tumor cells through targeting NOX4.

Regulatory T cells are an important prognostic factor in breast cancer: a systematic review and meta-analysis

The clinical relevance of regulatory T cell (Treg) infiltration in breast cancer (BC) remains controversial, and no recent meta-analysis has been published on this subject. Our aim was to identify the precise relationship between Tregs and the prognosis and clinic-pathological features of BC. Eligible articles were identified with a MEDLINE database search over a period up to March 2015. Our meta-analysis was performed using STATA software 11.0 and Review Manager 5.3. The correlations between Treg infiltration and clinico-pathological features and BC prognosis were analyzed. Subgroup and sensitivity analyses, as well as meta-regression, were conducted. Eighteen published studies (including 8,562 patients) were eligible. Overall survival (OS) and disease-, recurrence-, and progression-free survival (DFS/RFS/PFS) were correlated with Treg infiltration (OR=2.03 (95% CI, 1.40-2.95; P=0.000) and 1.48 (95% CI, 1.00-2.19; P=0.050), respectively), including 3-, 5-, and 10-year mortality rates. In addition, low Treg infiltration was present in estrogen receptor (ER)-positive tumors (P=0.000), progesterone receptor (PR)-positive tumors (P=0.003), Her2-negative tumors (P=0.000) and histological grade I/II tumors (P=0.001). No publication bias was observed with the exception of OS. Subgroup analysis suggested that the mortality rate of the high Treg infiltration subgroup was increased compared with the low Treg infiltration subgroup among ER-positive patients. Treg infiltration indicated a poorer prognosis for BC and is related to ER, PR, and Her2 status and histological grade. Thus, Treg infiltration could help predict outcomes and guide clinical therapy.

Expression of Kif5b protein is significantly associated with the progression, recurrence and prognosis of oral squamous cell carcinoma

OBJECTIVE

Kinesin family member 5b (Kif5b), a conventional kinesin, mainly participates in lysosome and mitochondria transportation. Some studies have indicated that Kif5b may be associated with the development of a variety of tumors. However, the role Kif5b plays in oral squamous cell carcinoma (OSCC) has yet to be determined. Our study aimed at investigating the expression level of Kif5b in primary OSCC and discussing its clinical significance in patients' outcomes.

PATIENTS AND METHODS

We measured Kif5b expression in 82 OSCC tissue samples with immunohistochemistry. The associations between the expression level of Kif5b and clinicopathological characteristics as well as patients' survival were statistically assessed.

RESULTS

Kif5b level was significantly associated with tumor size (p=0.034), histological differentiation (p=0.028), disease recurrence (p=0.018), surrounding tissue invasion (p=0.045), recurrence time (p=0.036) and survival status (p=0.030). Kaplan-Meier cumulative survival analyses indicated that high expression of Kif5b was linked to worse overall survival (p=0.0112) and disease-free survival (p=0.0085). The univariate and multivariate Cox proportional hazard analysis further identified the expression status of Kif5b as an independent variable that correlated with patients' survival and recurrence. Furthermore, in 54 early-stage, clinically node negative OSCC patients, Kif5b expression were correlated with histological differentiation (p=0.034), disease recurrence (p=0.038) and surrounding tissue invasion (p=0.029). Univariate and multivariable logistic regression results showed that only Kif5b expression level could influence the probability of recurrence.

CONCLUSIONS

Our results reveal that Kif5b expression is associated with poor clinical outcome in OSCC and even in early-stage, clinically node negative OSCC and may be a potential target for OSCC treatment.

Rankl expression predicts poor prognosis in gastric cancer patients: results from a retrospective and single-center analysis

The receptor activator of nuclear factor κB ligand (RANKL)/RANK pathway plays an important role in the prognosis of several solid tumor types, but its role in gastric cancer prognosis has been poorly characterized. A total of 116 gastric cancer patients who underwent surgical resection were enrolled in this study. Expressions of RANKL and RANK in gastric cancer tissues were detected using immunohistochemical staining. Thirty-eight patients (33%) showed a high level of RANKL expression and 61 patients (53%) showed a high level of RANK expression. There was a positive correlation between expressions of RANKL and RANK (P=0.014, r=0.221). A high level of RANKL expression indicated shorter overall survival (OS) (P=0.008), and was associated with a higher pathological tumor/lymph node/metastasis (pTNM) stage (P=0.035), while no significant correlation was detected between RANK expression and clinicopathological parameters. RANKL also predicted poor prognosis in patients with high RANK expression (P=0.008) and Bormann's type III/IV (P=0.002). Furthermore, RANKL expression correlated with pTNM stage according to high RANK expression (P=0.009), while no significance was found in patients with low RANK expression (P=1.000). Together, our results revealed that high expression of RANKL could predict worse outcomes in gastric cancer especially combined with RANK detection, and thereby this pathway could be a useful prognostic indicator of gastric cancer.

Fragmentation pattern of amides by EI and HRESI: study of protonation sites using DFT-3LYP data

Amides are important natural products which occur in a few plant families. Piplartine and piperine, major amides in Piper tuberculatum and P. nigrum, respectively, have shown a typical N–CO cleavage when analyzed by EI-MS or HRESI-MS. In this study several synthetic analogs of piplartine and piperine were subjected to both types of mass spectrometric analysis in order to identify structural features influencing fragmentation. Most of the amides showed an intense signal of the protonated molecule [M + H]⁺ when subjected to both HRESI-MS and EI-MS conditions, with a common outcome being the cleavage of the amide bond (N–CO). This results in the loss of the neutral amine or lactam and the formation of aryl acylium cations. The mechanism of N–CO bond cleavage persists in α,β-unsaturated amides because of the stability caused by extended conjugation. Computational methods determined that the protonation of the piperamides and their derivatives takes place preferentially at the amide nitrogen supporting the dominant the N–CO bond cleavage.

The N–CO cleavage of α,β-unsaturated piperamides under EI and ESI is supported by computational studies.

Exosomes promote cetuximab resistance via the PTEN/Akt pathway in colon cancer cells

Cetuximab is widely used in patients with metastatic colon cancer expressing wildtype KRAS. However, acquired drug resistance limits its clinical efficacy. Exosomes are nanosized vesicles secreted by various cell types. Tumor cell-derived exosomes participate in many biological processes, including tumor invasion, metastasis, and drug resistance. In this study, exosomes derived from cetuximab-resistant RKO colon cancer cells induced cetuximab resistance in cetuximab-sensitive Caco-2 cells. Meanwhile, exosomes from RKO and Caco-2 cells showed different levels of phosphatase and tensin homolog (PTEN) and phosphor-Akt. Furthermore, reduced PTEN and increased phosphorylated Akt levels were found in Caco-2 cells after exposure to RKO cell-derived exosomes. Moreover, an Akt inhibitor prevented RKO cell-derived exosome-induced drug resistance in Caco-2 cells. These findings provide novel evidence that exosomes derived from cetuximab-resistant cells could induce cetuximab resistance in cetuximab-sensitive cells, by downregulating PTEN and increasing phosphorylated Akt levels.

NDRG4, an early detection marker for colorectal cancer, is specifically expressed in enteric neurons

BACKGROUND

Promoter methylation of N-myc Downstream-Regulated Gene 4 (NDRG4) in fecal DNA is an established early detection marker for colorectal cancer (CRC). Despite its connection to CRC, NDRG4 is predominantly studied in brain and heart, with little to no knowledge about its expression or role in other organs. In this study, we aimed to determine the whole-body expression of NDRG4, with a focus on the intestinal tract.

METHODS

We investigated NDRG4 expression throughout the body by immunohistochemistry, Western Blotting and in situ mRNA hybridization using tissues from NDRG4 wild-type, heterozygous and knockout mice and humans. In addition, we explored cell-specific expression of NDRG4 in murine whole-mount gut preparations using immunofluorescence and confocal microscopy.

KEY RESULTS

NDRG4 is specifically expressed within nervous system structures throughout the body. In the intestinal tract of both mouse and man, NDRG4 immunoreactivity was restricted to the enteric nervous system (ENS), where it labeled cell bodies of the myenteric and submucosal plexuses and interconnecting nerve fibers. More precisely, NDRG4 expression was limited to neurons, as NDRG4 always co-localized with HuC/D (pan-neuronal marker) but never with GFAP (an enteric glial cell marker). Furthermore, NDRG4 was expressed in various neuropeptide Y positive neurons, but was only found in a minority (~10%) of neurons expressing neuronal nitric oxide synthase.

CONCLUSIONS AND INFERENCES

NDRG4 is exclusively expressed by central, peripheral and enteric neurons/nerves, suggesting a neuronal-specific role of this protein. Our findings raise the question whether NDRG4, via the ENS, an understudied component of the tumor microenvironment, supports CRC development and/or progression.

The influence of connective tissue growth factor on rabbit ligament injury repair

Objectives

The injured anterior cruciate ligament (ACL) is thought to exhibit an impaired healing response, and attempts at surgical repair have not been successful. Connective tissue growth factor (CTGF) is reported to be associated with wound healing, probably through transforming growth factor beta 1 (TGF-β1).

Methods

A rabbit ACL injury model was used to study the effect of CTGF on ligament recovery. Quantitative real-time PCR (qRT-PCR) was performed for detection of changes in RNA levels of TGF-β1, type 1 collagen (COL1), type 2 collagen (COL2), SRY-related high mobility group-box gene9 (SOX9), tissue inhibitor of metalloproteinase-1 (TIMP-1) and matrix metallopeptidase 13 (MMP-13). Expression of related proteins was detected by Western blotting.

Results

The current study showed that CTGF could promote the recovery of an injured anterior cruciate ligament. It can upregulate mRNA and expression of TGF-β1, COL1, COL2, SOX9, and tissue inhibitor of TIMP-1, and downregulate mRNA and expression of MMP-13, suggesting that the curative effect of CTGF on injured rabbit ligaments is through regulation of these cellular factors.

Conclusions

This finding revealed the healing role of CTGF in injured tissues and provides new possibilities of treating injured tissues and wound healing by using CTGF.

Cite this article: X. Sun, W. Liu, G. Cheng, X. Qu, H. Bi, Z. Cao, Q. Yu. The influence of connective tissue growth factor on rabbit ligament injury repair. Bone Joint Res 2017;6:399–404. DOI: 10.1302/2046-3758.67.BJR.2016-0255.R1.

Mucosa-associated microbiota signature in colorectal cancer

The aim of this study was to explore the gut microbiota profiles of colorectal cancer (CRC) patients and to examine the relationship between gut microbiota and other key molecular factors involved in CRC tumorigenesis. In this study, a 16S rDNA sequencing platform was used to identify possible differences in the microbiota signature between CRC and adjacent normal mucosal tissue. Differences in the microbiota composition in different anatomical colorectal tumor sites and their potential association with KRAS mutation were also explored. In this study, the number of Firmicutes and Actinobacteria decreased, while the number of Fusobacteria increased in the gut of CRC patients. In addition, at the genus level, Fusobacterium was identified as the key contributor to CRC tumorigenesis. In addition, a different distribution of gut microbiota in ascending and descending colon cancer samples was observed. Lipopolysaccharide biosynthesis-associated microbial genes were enriched in tumor tissues. Our study suggests that specific mucosa-associated microbiota signature and function are significantly changed in the gut of CRC patients, which may provide insight into the progression of CRC. These findings could also be of value in the creation of new prevention and treatment strategies for this type of cancer.

Characterization of retroviral infectivity and superinfection resistance during retrovirus-mediated transduction of mammalian cells

Retroviral vectors including lentiviral vectors are commonly used tools to stably express transgenes or RNA molecules in mammalian cells. Their utilities are roughly divided into two categories, stable overexpression of transgenes and RNA molecules, which requires maximal transduction efficiency, or functional selection with retrovirus (RV)-based libraries, which takes advantage of retroviral superinfection resistance. However, the dynamic features of RV-mediated transduction are not well characterized. Here, we engineered two murine stem cell virus-based retroviral vectors expressing dual fluorescence proteins and antibiotic markers, and analyzed virion production efficiency and virion stability, dynamic infectivity and superinfection resistance in different cell types, and strategies to improve transduction efficiency. We found that the highest virion production occurred between 60 and 72 h after transfection. The stability of the collected virion supernatant decreased by >60% after 3 days in storage. We found that RV infectivity varied drastically in the tested human cancer lines, while low transduction efficiency was partially overcome with increased virus titer, prolonged infection duration and/or repeated infections. Furthermore, we demonstrated that RV receptors PIT1 and PIT2 were lowly expressed in the analyzed cells, and that PIT1 and/or PIT2 overexpression significantly improved transduction efficiency in certain cell lines. Thus, our findings provide resourceful information for the optimal conditions of retroviral-mediated gene delivery.

Human β-defensin-3 induces IL-8 release and apoptosis in airway smooth muscle cells

BACKGROUND

Human airway smooth muscle cells (ASMCs) may have a pro-inflammatory role through the release of inflammatory mediators. Increasing evidence indicates that human β-defensins (HBDs) are related to pathogenesis of asthma.

OBJECTIVES

To examine the plasma level of HBD-1, HBD-2 and HBD-3 in asthmatic patients and the expression of their mouse orthologues in the lung tissue of a mouse model of chronic severe asthma. Further to investigate the effect of HBD-3 on the release of the pro-inflammatory cytokine IL-8 and to explore the mechanisms.

METHODS

The plasma levels of HBD-1, HBD-2 and HBD-3 from 34 healthy controls and 25 asthmatic patients were determined by ELISA. The expression of mouse β-defensins MBD-1, MBD-3 and MBD-14 in the lung tissue of asthmatic mice was detected by Western blot. The ASMCs were cultured with HBD-3 for 24 hour, and then the supernatant level of IL-8 was evaluated by ELISA and the cell viability was examined by WST-1 assay. The signalling pathway was investigated with blocking antibodies or pharmacological inhibitors.

RESULTS

The plasma levels of HBD-1 and HBD-3 were elevated in asthmatic patients, and the expression of MBD-14, the mouse orthologue for HBD-3, was increased in asthmatic mice. HBD-3-induced IL-8 production in a CCR6 receptor-specific manner and was dependent on multiple signalling pathways. Moreover, HBD-3-induced cell apoptosis concurrently, which was dependent on the ERK1/2 MAPK pathway. Mitochondrial ROS regulated both HBD-3-induced IL-8 production and cell apoptosis.

CONCLUSIONS AND CLINICAL RELEVANCE

These observations provide clear evidence of an important new mechanism for the promotion of airway inflammation and tissue remodelling with potential relevance for the treatment of asthma.

The influence of delipidation on triglyceride and LIPIN1 of porcine embryos derived from parthenogenetic activation

Proteins in the LIPIN family play key roles in lipid synthesis mainly on triacylglycerol (TAG) biosynthesis, and they also act as transcriptional coactivators to regulate the expression of genes involved in lipid metabolism with other nuclear factors. Hence, this study was designed to investigate LIPIN1 in pig oocytes and embryos by the delipidation. After delipidation, the content of lipids (LDs) and TAG in MII oocyte was significantly reduced; however, a similar increasing tendency of TAG was shown during embryos development. Subsequently, the expression of genes related to TAG biosynthesis including GPAT1, AGPAT1, AGPAT2, LIPIN1, DGAT and the nuclear factors interacted with LIPIN1 including PPARα and PPARγ was investigated. It is obvious that DGAT and GPAT1, and LIPIN1 increased significantly after delipidation at 1-cell and 4-cell stage, and the expression of PPARα and PPARγ also increased at 4-cell stage. By immunofluorescence staining and Western blots, LIPIN1 was found to exhibit a dynamic localization pattern and gradually increase with the development of delipated embryo. In the early developmental stages (1-, 2- and 4-cell stages), it was distributed over the cortical layer. But at the blastocyst stage, a homogeneous distribution of LIPIN1 was observed in cytoplasm. At 2-cell stage, the expression of PPARα decreased when LIPIN1 was interfered by small interfering RNA, but PPARγ has no significant difference. Therefore, in this study, we find after delipidation, the content of TAG and LIPIN1 will gradually increase during embryo development and nuclear factor PPARα and PPARγ can also be affected by delipidation. The interaction of LIPIN1 and PPARα exists in porcine embryo.

The Patterns of Practice and Outcomes of Penile Cancer in Ontario

AIMS

Penile cancer is a rare malignancy in Western countries. The management guidelines are mainly derived from retrospective studies as there are no randomised trials. The primary objective of this study was to assess patterns of practice and outcomes of penile squamous cell carcinoma in Ontario. Secondary objectives included examining trends in incidence, pathological characteristics and prognostic factors.

MATERIALS AND METHODS

All patients diagnosed with penile cancer between 2000 and 2010 were identified from the Ontario Cancer Registry and all available pathology reports related to penile cancer during this period were reviewed.

RESULTS

Pathology reports of 419 new cases of penile squamous cell carcinoma were reviewed. There was a significant improvement in completeness of the pathology reports in recent years. The age-adjusted incidence was 0.9 per 100 000 person-years. Most patients presented with a pT1 lesion (63%). A partial penectomy (40%) was the most common surgical procedure. Over 38% of patients identified to be eligible for organ-sparing surgery had a total or partial penectomy. Only 23% of the eligible patients identified to require lymph node dissection underwent the procedure. The 5 year disease-specific survival for stage 0, I, II, III were 94%, 93%, 74% and 52%, respectively.

CONCLUSIONS

There is a significant variation in the patterns of practice in Ontario. A large proportion of patients in this cohort were probably overtreated for the primary malignancy and undertreated for the regional nodes.

ARHGAP10, downregulated in ovarian cancer, suppresses tumorigenicity of ovarian cancer cells

Rho GTPase-activating proteins (RhoGAPs) are implicated in the development and progression of ovarian cancer. ARHGAP10 is a member of RhoGAP proteins and inactivates Cdc42 by converting GTP-bound form to GDP-bound form. Here, we aimed to evaluate ARHGAP10 expression profile and functions in ovarian cancer. The decreased expression of ARHGAP10 was found in 77.3% (58/75) of ovarian cancer tissues, compared with their non-tumorous counterparts. Furthermore, overall survival in ovarian cancer patients with higher expression of ARHGAP10 was longer than those with lower expression. Ectopic expression of ARHGAP10 in two ovarian cancer cell lines with lower expression of ARHGAP10 (A2780 and HO-8910) dramatically suppressed cell proliferation in vitro. In nude mice, its stable overexpression significantly inhibited the tumorigenicity of A2780 cells. We further demonstrated that overexpression of ARHGAP10 significantly inhibited cell adhesion, migration and invasion, resulted in cell arrest in G1 phase of cell cycle and a significant increase of apoptosis. Moreover, ARHGAP10 interacted with Cdc42 and overexpression of ARHGAP10 inhibited the activity of Cdc42 in A2780 cells. Gene set enrichment analysis on The Cancer Genome Atlas dataset showed that KEGG cell cycle, replication and base excision repair (BER) pathways were correlatively with the ARHGAP10 expression, which was further confirmed in ovarian cancer cells by western blotting. Hence, ARHGAP10 may serve as a tumor suppressor through inactivating Cdc42, as well as inhibiting cell cycle, replication and BER pathways. Our data suggest an important role of ARHGAP10 in the molecular etiology of cancer and implicate the potential application of ARHGAP10 in cancer therapy.