Pan-Cancer Proteomics Analysis Reveals Wiskott-Aldrich Syndrome Protein as a Potential Regulator of Programmed Death-Ligand 1

The programmed death-ligand 1 (PD-L1) is a key mediator of immunosuppression in the tumor microenvironment. The expression of PD-L1 in cancer cells is useful for the clinical determination of an immune checkpoint blockade (ICB). However, the regulatory mechanism of the PD-L1 abundance remains incompletely understood. Here, we integrated the proteomics of 52 patients with solid tumors and examined immune cell infiltration to reveal PD-L1-related regulatory modules. Wiskott-Aldrich syndrome protein (WASP) was identified as a potential regulator of PD-L1 transcription. In two independent cohorts containing 164 cancer patients, WASP expression was significantly associated with PD-L1. High WASP expression contributed to immunosuppressive cell composition, including cells positive for immune checkpoints (PD1, CTLA4, TIGIT, and TIM3), FoxP3+ Treg cells, and CD163+ tumor-associated macrophages. Overexpression of WASP increased, whereas knockdown of WASP decreased the protein level of PD-L1 in cancer cells without alteration of PD-L1 protein stability. The WASP-mediated cell migration and invasion were markedly attenuated by the silence of PD-L1. Collectively, our data suggest that WASP is a potential regulator of PD-L1 and the WASP/PD-L1 axis is responsible for cell migration and an immunosuppressive microenvironment.

HnRNPR-mediated UPF3B mRNA splicing drives hepatocellular carcinoma metastasis

INTRODUCTION

Abnormal alternative splicing (AS) contributes to aggressive intrahepatic invasion and metastatic spread, leading to the high lethality of hepatocellular carcinoma (HCC).

OBJECTIVES

This study aims to investigate the functional implications of UPF3B-S (a truncated oncogenic splice variant) in HCC metastasis.

METHODS

Basescope assay was performed to analyze the expression of UPF3B-S mRNA in tissues and cells. RNA immunoprecipitation, and in vitro and in vivo models were used to explore the role of UPF3B-S and the underlying mechanisms.

RESULTS

We show that splicing factor HnRNPR binds to the pre-mRNA of UPF3B via its RRM2 domain to generate an exon 8 exclusion truncated splice variant UPF3B-S. High expression of UPF3B-S is correlated with tumor metastasis and unfavorable overall survival in patients with HCC. The knockdown of UPF3B-S markedly suppresses the invasive and migratory capacities of HCC cells in vitro and in vivo. Mechanistically, UPF3B-S protein targets the 3'-UTR of CDH1 mRNA to enhance the degradation of CDH1 mRNA, which results in the downregulation of E-cadherin and the activation of epithelial-mesenchymal transition. Overexpression of UPF3B-S enhances the dephosphorylation of LATS1 and the nuclear accumulation of YAP1 to trigger the Hippo signaling pathway.

CONCLUSION

Our findings suggest that HnRNPR-induced UPF3B-S promotes HCC invasion and metastasis by exhausting CDH1 mRNA and modulating YAP1-Hippo signaling. UPF3B-S could potentially serve as a promising biomarker for the clinical management of invasive HCC.

[Clinical efficacy of single/double 125I-seed strands combined with biliary stents in the treatment of malignant obstructive jaundice]

Objective: To compare the clinical efficacy of single/double 125I-seed strands combined with biliary stents in the treatment of malignant obstructive jaundice. Methods: Totally 67 cases of patients with malignant obstructive jaundice who received single/double125I-seed strands combined with biliary stents implantation from September 2018 to December 2021 were analyzed retrospectively. Among them, 36 patients received single 125I-seed strands combined with biliary stents (single strand group) and 31 patients received double 125I-seed strands combined with biliary stents(double strands group). The technical success rate, clinical success rate, complications, biochemical and tumor indexes at 8 weeks after operation [total bilirubin (TB), direct bilirubin (DB), alanine transaminase (ALT), aspartate transaminase (AST), carbohydrate antigen 19-9 (CA19-9)], stent patency time (SP), median progression-free survival time (mPFS) and median survival time (mOS) were analyzed. Results: There was no significant difference (P>0.05) in technical success rate (100% vs 100%), clinical success rate (97.2% vs 96.8%) and major complications (5.6% vs 6.5%) between single strand group and double strands group. There were significant differences in TB, DB, ALT, AST and CA19-9 indicators between the two groups before and 8 weeks after operation (all P<0.05), but there was no significant difference in the difference value of preoperative and postoperative 8-week indicators between the two groups (all P>0.05).The SP and mPFS of double-stranded stents were longer than those of single-stranded stents.[8.6 months (95%CI:6.9-10.4) vs 6.2 months (95%CI:5.8-6.6), 3.2 months (95%CI:3.0-3.4) vs 3.0 months (95%CI:2.9-3.1), all P<0.05]. The mOS of single and double strands groups was 11.2 months (95%CI:8.3-14.1) and 13.4 months (95%CI:9.9-16.9) respectively, with no statistical difference (P=0.137). Conclusion: Compared with single 125I-seed strands, double 125I-seed strands can prolong biliary SP and mPFS, but the long-term survival index still needs further observation.

LINC00493-encoded microprotein SMIM26 exerts anti-metastatic activity in renal cell carcinoma

Human microproteins encoded by long non-coding RNAs (lncRNA) have been increasingly discovered, however, complete functional characterization of these emerging proteins is scattered. Here, we show that LINC00493-encoded SMIM26, an understudied microprotein localized in mitochondria, is tendentiously downregulated in clear cell renal cell carcinoma (ccRCC) and correlated with poor overall survival. LINC00493 is recognized by RNA-binding protein PABPC4 and transferred to ribosomes for translation of a 95-amino-acid protein SMIM26. SMIM26, but not LINC00493, suppresses ccRCC growth and metastatic lung colonization by interacting with acylglycerol kinase (AGK) and glutathione transport regulator SLC25A11 via its N-terminus. This interaction increases the mitochondrial localization of AGK and subsequently inhibits AGK-mediated AKT phosphorylation. Moreover, the formation of the SMIM26-AGK-SCL25A11 complex maintains mitochondrial glutathione import and respiratory efficiency, which is abrogated by AGK overexpression or SLC25A11 knockdown. This study functionally characterizes the LINC00493-encoded microprotein SMIM26 and establishes its anti-metastatic role in ccRCC, and therefore illuminates the importance of hidden proteins in human cancers.

A five-protein prognostic signature with GBP2 functioning in immune cell infiltration of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is of poor clinical outcomes, and currently lacks reliable prognostic biomarkers. By analyzing the datasets of the Cancer Genome Atlas (TCGA) and the Clinical Proteomic Tumor Analysis Consortium (CPTAC), we established a five-protein prognostic signature containing GBP2, HLA-DRA, ISG15, ISG20 and ITGAX. Our data indicate that this signature was closely correlated with advanced stage, higher pathological grade, and unfavorable survivals in patients with ccRCC. We further functionally characterized GBP2. Overexpression of GBP2 enhanced the phosphorylation of STAT2 and STAT3 to trigger JAK-STAT signaling and promote cell migration and invasion in ccRCC. Treatment of Ruxolitinib, a specific inhibitor of JAK/STAT, attenuated the GBP2-mediated phenotypes. Patients with high GBP2 expression were accompanied with more infiltration of immune cells positively stained with CD3, CD8, CD68, and immune checkpoint markers PD-1 and CTLA4, which was validated by Opal multiplex immunohistochemistry in ccRCC tissues. More CD8 + T cells and CD68 + macrophages were observed in patients expressing high GBP2. Taken together, a five-protein prognostic signature was constructed in our study. GBP2 has an oncogenic role via modulating JAK-STAT signaling and tumor immune infiltration, and thus may serve as a potential therapeutic target in ccRCC.

EFHD1, a novel mitochondrial regulator of tumor metastasis in clear cell renal cell carcinoma

The biological function of many mitochondrial proteins in mechanistic detail has not been well investigated in clear cell renal cell carcinoma (ccRCC). A seven-mitochondrial-gene signature was generated by Lasso regression analysis to improve the prediction of prognosis of patients with ccRCC, using The Cancer Genome Atlas and Clinical Proteomic Tumor Analysis Consortium cohort. Among those seven genes, EFHD1 is less studied and its role in the progression of ccRCC remains unknown. The decreased expression of EFHD1 was validated in clinical samples and was correlated with unfavorable outcome. Overexpression of EFHD1 in ccRCC cells resulted in the reduction of mitochondrial Ca²⁺ , and the inhibition of cell migration and invasion in vitro and tumor metastasis in vivo. Mechanistically, EFHD1 physically bound to the core mitochondrial calcium transporter (mitochondrial calcium uniporter, MCU) through its N-terminal domain. The interaction between EFHD1 and MCU suppressed the uptake of Ca²⁺ into mitochondria, and deactivated the Hippo/YAP signaling pathway. Further data revealed that the ectopic expression of EFHD1 upregulated STARD13 to enhance the phosphorylation of YAP protein at Ser-127. The knockdown of STARD13 or the overexpression of MCU partly abrogated the EFHD1-mediated induction of phosphorylation of YAP at Ser-127 and suppression of cell migration. Taken together, the newly identified EFHD1-MCU-STARD13 axis participates in the modulation of the Hippo/YAP pathway and serves as a novel regulator in the progression of ccRCC.

[Effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits]

Objective: To study the effects of vibration on the expression of mitochondrial fusion and fission genes and ultrastructure of skeletal muscle in rabbits. Methods: Thirty-two 3.5-month-old New Zealand rabbits were randomly divided into low-intensity group, medium-intensity group, high-intensity group and control group, with 8 rabbits in each group. The rabbits in the experimental group were subjected to hind limb vibration load test for 45 days. The vibration intensity of the high intensity group was 12.26 m/s(2), the medium intensity group was 6.13 m/s(2), and the low intensity group was 3.02 m/s(2) according to the effective value of weighted acceleration[a(hw (4))] for 4 hours of equal energy frequency. The control group was exposed to noise only in the same experimental environment as the medium-intensity group. The noise levels of each group were measured during the vibration load experiment. After the test, the mRNA expression of mitochondrial fusion gene (Mfn1/Mfn2) and fission gene (Fis1, Drp1) by RT-PCR in the skeletal muscles were measured and the ultrastructure of the skeletal muscles were observed in high intensity group. Results: The mRNA expression of mitochondrial in the skeletal muscle tissues of control group, low intensity group, medium intensity group and high intensity group were Mfn1: 3.25±1.36, 3.85±1.90, 4.53±2.31 and 11.63±7.68; Mfn2: 0.68±0.25, 1.02±0.40, 0.94±0.33 and 1.40±0.45; Fis1: 1.05±0.62, 1.15±0.59, 1.53±1.06 and 2.46±1.51 and Drp1: 3.72±1.76, 2.91±1.63, 3.27±2.01 and 4.21±2.46, respectively. Compared with the control group, the expressions of Mfn1 mRNA, Mfn2 mRNA and Fis1 mRNA in the high-intensity group increased significantly (P<0.05) , and the expressions of Mfn2 mRNA in the medium-intensity group and the low-intensity group increased significantly (P<0.05) . Compared with the control group, the ultrastructure of skeletal muscle of high intensity group showed mitochondrial focal accumulation, cristae membrane damage, vacuole-like changes; Z-line irregularity of muscle fibers, and deficiency of sarcomere. Conclusion: Vibration must be lead to the abnormal mitochondrial morphology and structure and the disorder of energy metabolism due to the expression imbalance of mitochondrial fusion and fission genes in skeletal muscles of rabbits, which may be an important target of vibration-induced skeletal muscle injury.

Comparison of RNAscope and immunohistochemistry for evaluation of the UPK2 status in urothelial carcinoma tissues

BACKGROUND

UPK2 exhibits excellent specificity for urothelial carcinoma (UC). UPK2 evaluation can be useful in making the correct diagnosis of UC. However, UPK2 detection by immunohistochemistry (IHC) has relatively low sensitivity. This paper aimed to compare the diagnostic sensitivity of RNAscope and IHC for evaluation of the UPK2 status in UC.

METHODS

Tissue blocks from 127 conventional bladder UCs, 45 variant bladder UCs, 24 upper tract UCs and 23 metastatic UCs were selected for this study. IHC and RNAscope were used to detect the UPK2 status in UCs. Then, comparisons of the two methods were undertaken.

RESULTS

There was no significant difference between RNAscope and IHC for the evaluation of the UPK2 positivity rate in UC (68.0% vs. 62.6%, P = 0.141). Correlation analysis revealed a moderate positive correlation for detection of UPK2: RNAscope vs. IHC (P < 0.001, R = 0.441). Our results showed a trend toward a higher positive UPK2 rate detected by RNAscope (53.3%) than by IHC (35.6%) in variant bladder UCs. Disappointingly, the P value did not indicate a significant difference (P = 0.057).

CONCLUSIONS

RNAscope for UPK2 appeared to perform similarly to IHC, with a marginally higher positive rate, suggesting it could be used as an alternative or adjunct to UPK2 IHC.

Cell-free DNA from bile outperformed plasma as a potential alternative to tissue biopsy in biliary tract cancer

BACKGROUND

Biliary tract cancers (BTCs) are rare and highly heterogenous malignant neoplasms. Because obtaining BTC tissues is challenging, the purpose of this study was to explore the potential roles of bile as a liquid biopsy medium in patients with BTC.

PATIENTS AND METHODS

Sixty-nine consecutive patients with suspected BTC were prospectively enrolled in this study. Capture-based targeted sequencing was performed on tumor tissues, whole blood cells, plasma, and bile samples using a large panel consisting of 520 cancer-related genes.

RESULTS

Of the 28 patients enrolled in this cohort, tumor tissues were available in eight patients, and plasma and bile were available in 28 patients. Somatic mutations were detected in 100% (8/8), 71.4% (20/28), and 53.6% (15/28) of samples comprising tumor tissue DNA, bile cell-free DNA (cfDNA), and plasma cfDNA, respectively. Bile cfDNA showed a significantly higher maximum allele frequency than plasma cfDNA (P = 0.0032). There were 56.2% of somatic single-nucleotide variant (SNVs)/insertions and deletions (indels) shared between bile and plasma cfDNA. When considering the genetic profiles of tumor tissues as the gold standard, the by-variant sensitivity and positive predictive value for SNVs/indels in bile cfDNA positive for somatic mutations were both 95.5%. The overall concordance for SNVs/indels in bile was significantly higher than that in plasma (99.1% versus 78.3%, P < 0.0001). Moreover, the sensitivity of CA 19-9 combined with bile cfDNA achieved 96.4% in BTC diagnosis.

CONCLUSION

We demonstrated that bile cfDNA was superior to plasma cfDNA in the detection of tumor-related genomic alterations. Bile cfDNA as a minimally invasive liquid biopsy medium might be a supplemental approach to confirm BTC diagnosis.

An E2F1/DDX11/EZH2 Positive Feedback Loop Promotes Cell Proliferation in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for one of the leading causes of cancer-related death, and is attributed to the dysregulation of genes involved in genome stability. DDX11, a DNA helicase, has been implicated in rare genetic disease and human cancers. Yet, its clinical value, biological function, and the underlying mechanism in HCC progression are not fully understood. Here, we show that DDX11 is upregulated in HCC and exhibits oncogenic activity via EZH2/p21 signaling. High expression of DDX11 is significantly correlated with poor outcomes of HCC patients in two independent cohorts. DDX11 overexpression increases HCC cell viabilities and colony formation, whereas DDX11 knockdown arrests cells at G1 phase without alteration of p53 expression. Ectopic expression of DDX11 reduces, while depletion of DDX11 induces the expression of p21. Treatment of p21 siRNA markedly attenuates the cell growth suppression caused by DDX11 silence. Further studies reveal that DDX11 interacts with EZH2 in HCC cells to protect it from ubiquitination-mediated protein degradation, consequently resulting in the downregulation of p21. In addition, E2F1 is identified as one of the upstream regulators of DDX11, and forms a positive feedback loop with EZH2 to upregulate DDX11 and facilitate cell proliferation. Collectively, our data suggest DDX11 as a promising prognostic factor and an oncogene in HCC via a E2F1/DDX11/EZH2 positive feedback loop.

FMNL1 Exhibits Pro-Metastatic Activity via CXCR2 in Clear Cell Renal Cell Carcinoma

Formin-like (FMNL) proteins are responsible for cytoskeletal remodeling and have been implicated in the progression and spread of human cancers. Yet the clinical significance and biological function of FMNL1 in clear cell renal cell carcinoma (ccRCC) remain unclear. In this study, the expression of FMNL1 in ccRCC and its clinical value were determined by tissue microarray-based IHC and statistical analyses. The role of FMNL1 in ccRCC metastasis and the underlying mechanism were investigated via in vitro and in vivo models using gene regulation detection, ChIP, Luciferase reporter assays, and rescue experiments. We show that FMNL1 is upregulated in ccRCC and exhibits pro-metastatic activity via induction of CXCR2. High expression of FMNL1 is significantly correlated with advanced tumor stage, higher pathological tumor grade, tumor metastasis, and unfavorable prognosis in two independent cohorts containing over 800 patients with ccRCC. The upregulation of FMNL1 in ccRCC is mediated by the loss of GATA3. Ectopic expression of FMNL1 promotes, whereas FMNL1 depletion inhibits cell migration in vitro and tumor metastasis in vivo. The FMNL1-enhanced cell mobility is markedly attenuated by the knockdown of CXCR2. Further studies demonstrate that FMNL1 increases the expression of CXCR2 via HDAC1. In clinical samples, FMNL1 expression is positively associated with CXCR2, and is negatively connected to GATA3 expression. Collectively, our data suggest FMNL1 serve as a potential prognostic factor and function as an oncogene. The axis of GATA3/FMNL1/CXCR2 may present a promising therapeutic target for tumor metastasis in ccRCC.

CBX4 transcriptionally suppresses KLF6 via interaction with HDAC1 to exert oncogenic activities in clear cell renal cell carcinoma

Background

Dysregulation of polycomb chromobox (CBX) proteins that mediate epigenetic gene silencing contributes to the progression of human cancers. Yet their roles in clear cell renal cell carcinoma (ccRCC) remain to be explored.

Methods

The expression of CBX4 and its clinical significance were determined by qRT-PCR, western blot, immunohistochemistry and statistical analyses. The biological function of CBX4 in ccRCC tumor growth and metastasis and the underlying mechanism were investigated using in vitro and in vivo models.

Findings

CBX4 exerts oncogenic activities in ccRCC via interaction with HDAC1 to transcriptionally suppress tumor suppressor KLF6. CBX4 expression is increased in ccRCC and correlated with poor prognosis in two independent cohorts containing 840 patients. High CBX4 expression is significantly associated with Fuhrman grade and tumor lymph node invasion. CBX4 overexpression promotes tumor growth and metastasis, whereas CBX4 knockdown results in the opposite phenotypes. Mechanistically, CBX4 downregulates KLF6 via repressing the transcriptional activity of its promoter. Further studies show that CBX4 physically binds to HDAC1 to maintain its localization on the KLF6 promoter. Ectopic expression of KLF6 or disruption of CBX4-HDAC1 interaction attenuates CBX4-mediated cell growth and migration. Furthermore, CBX4 depletion markedly enhances the histone deacetylase inhibitor (HDACi)-induced cell apoptosis and suppression of tumor growth.

Interpretation

Our data suggest CBX4 as an oncogene with prognostic potential in ccRCC. The newly identified CBX4/HDAC1/KLF6 axis may represent a potential therapeutic target for the clinical intervention of ccRCC.

Loss of RDM1 enhances hepatocellular carcinoma progression via p53 and Ras/Raf/ERK pathways

Hepatocellular carcinoma (HCC), with its ineffective therapeutic options and poor prognosis, represents a global threat. In the present study, we show that RAD52 motif 1 (RDM1), a key regulator of DNA double‐strand break repair and recombination, is downregulated in HCC tissues and suppresses tumor growth. In clinical HCC samples, low expression of RDM1 correlates with larger tumor size, poor tumor differentiation, and unfavorable survival. In vitro and in vivo data demonstrate that knockdown of RDM1 increases HCC cell proliferation, colony formation, and cell population at G2/M phase, whereas RDM1 overexpression results in the opposite phenotypes. Mechanistically, RDM1 binds to the tumor suppressor p53 and enhances its protein stability. In the presence of p53, RDM1 suppresses the phosphorylation of Raf and ERK. Overexpression of p53 or treatment with ERK inhibitor significantly abolishes cell proliferation induced by the depletion of RDM1. In addition, overexpression of methyltransferase‐like 3 markedly induces N6‐methyladenosine modification of RDM1 mRNA and represses its expression. Taken together, our study indicates that RDM1 functions as a tumor suppressor and may be a potential prognostic and therapeutic factor for HCC.

[Targeted therapy for malignant peripheral nerve sheath tumor: translational research and clinical application]

Malignant peripheral nerve sheath tumor (MPNST) is a rare invasive soft tissue sarcoma that originates from peripheral nerve branches and peripheral nerve sheaths. Early radical surgery is an effective treatment for MPNST. Since it is insensitive to radiotherapy and chemotherapy, the disease manifests a rapid progression, poor prognosis and high mortality. In recent years, the translational researches on the driving factors and therapeutic targets of MPNST have been rapidly developed, including the pathways of NF1-Ras, Raf-MEK-ERK, PI3K-AKT-mTOR, Wnt signaling, and abnormal expressions of apoptotic proteins, the general loss of polycomb repressive complex 2 (PRC2), upregulation of the HDAC family, abnormal expressions of receptor tyrosine kinases, expressions of programmed cell death ligand (PD-L1), aurora kinase and various microRNAs.This review summarizes the current translational researches on potential therapeutic targets of MPNST, and the clinical trials which provide helpful information for MPNST targeted therapy.

A Coiled-Coil Domain Containing 50 Splice Variant Is Modulated by Serine/Arginine-Rich Splicing Factor 3 and Promotes Hepatocellular Carcinoma in Mice by the Ras Signaling Pathway

Deregulation of alternative splicing contributes to the malignant progression of cancer. Little is known about the significant alternative splicing events in hepatocellular carcinoma (HCC). High-throughput sequencing revealed that coiled-coil domain containing 50 (CCDC50) pre-mRNA is aberrantly spliced in 50% of our HCC cases. A BaseScope assay was performed to examine the expression of CCDC50S (a truncated oncogenic splice variant) in HCC tissues. Compared with benign liver tumors and several other types of solid tumors, CCDC50S mRNA was up-regulated in HCC, with a diagnostic potential (sensitivity, 0.711; specificity, 0.793). High expression of CCDC50S mRNA in HCC was significantly correlated with poor tumor differentiation, advanced tumor node metastasis (TNM) stage, and unfavorable prognosis. Overexpression of CCDC50S exerted tumorigenic activities that promoted HCC growth and metastasis by activation of Ras/forkhead box protein O4 (Foxo4) signaling. Either suppression of mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) phosphorylation or overexpression of Foxo4 markedly attenuated CCDC50S-mediated phenotypes. Furthermore, serine- and arginine-rich splicing factor 3 (SRSF3) directly bound to CCDC50S mRNA to maintain its stability in the cytoplasm. The cytosolic retention of SRSF3 was mediated by the interaction of hepatitis B virus-encoded X protein (HBx) and 14-3-3β. Ectopic HBx expression induced expression of cytosolic SRSF3 and CCDC50S. Conclusion: Our study provided compelling evidence that up-regulation of CCDC50S was modulated by HBx/SRSF3/14-3-3β complex and enhanced oncogenic progression of HCC through the Ras/Foxo4 signaling pathway. These data suggest that CCDC50S may serve as a diagnostic and prognostic biomarker and probably a promising therapeutic target in HCC.

A GYS2/p53 Negative Feedback Loop Restricts Tumor Growth in HBV-Related Hepatocellular Carcinoma

Hepatocellular carcinogenesis is attributed to the reprogramming of cellular metabolism as a consequence of the alteration in metabolite-related gene regulation. Identifying the mechanism of aberrant metabolism is of great potential to provide novel targets for the treatment of hepatocellular carcinoma (HCC). Here, we demonstrated that glycogen synthase 2 (GYS2) restricted tumor growth in hepatitis B virus-related HCC via a negative feedback loop with p53. Expression of GYS2 was significantly downregulated in HCC and correlated with decreased glycogen content and unfavorable patient outcomes. GYS2 overexpression suppressed, whereas GYS2 knockdown facilitated cell proliferation in vitro and tumor growth in vivo via modulating p53 expression. GYS2 competitively bound to MDM2 to prevent p53 from MDM2-mediated ubiquitination and degradation. Furthermore, GYS2 enhanced the p300-induced acetylation of p53 at K373/382, which in turn inhibited the transcription of GYS2 in the support of HBx/HDAC1 complex. In summary, our findings suggest that GYS2 serves as a prognostic factor and functions as a tumor suppressor in HCC. The newly identified HBx/GYS2/p53 axis is responsible for the deregulation of glycogen metabolism and represents a promising therapeutic target for the clinical management of HCC. SIGNIFICANCE: We elucidated the clinical significance, biological function, and regulation of the HBx/GYS2/p53 axis, which supplement the understanding of tumor glycogen metabolism and provide potential prognostic and therapeutic targets for HCC treatment.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/79/3/534/F1.large.jpg.

[Effect of silica dust on protein oxidative injury in lung tissue of mice]

Objective: To investigate the effect of silica dust on protein oxidative injury in the lung tissue of mice. Methods: A total of 60 mice were randomly divided into control group (not exposed to dust) , 2-hour group (inhalation of dust for 2 hours per day) , 4-hour group (inhalation of dust for 4 hours per day) , and 8-hour group (inhalation of dust for 8 hours per day) , with 15 mice in each group. During dust exposure, the mice were placed in a dust exposure cabinet; the dust was blown with an air blower and the concentration was maintained at 125 mg/m(3). All mice were exposed to silica dust for 3 weeks. The changes of the lung were observed after dust exposure ended, and spectrophotometry was performed to measure the activity of superoxide dismutase (SOD) and the content of malondialdehyde (MDA) and protein carbonyl in the lung tissue. Results: The 2-, 4-, and 8-hour groups had marked edema, sporadic punctate hemorrhage, and nodular shadow in the lungs. Compared with the control group, the 2-, 4-, and 8-hour groups had a significant increase in lung coefficient (7.03±0.78 mg/g, 8.48±0.93 mg/g, and 8.99±0.85 mg/g vs 5.52±0.81 mg/g, P<0.05) . Compared with the control group, the 2-, 4-, and 8-hour groups had significant increases in the content of MDA (2.83±0.52, 3.94±0.65, and 4.56±0.77 nmol/mg prot vs 1.26±0.36 nmol/mg prot, P<0.05) and protein carbonyl (1.61±0.44, 1.96±0.47, and 2.20±0.58 nmol/mg prot vs 1.13±0.21 nmol/mg prot, P<0.05) in lung tissue. The 4- and 8-hour groups had a significantly lower activity of SOD than the control group (153.69±20.58 and 140.35±18.97 U/mg prot vs 186.00±25.46 U/mg prot, P<0.05) . Conclusions: Silica dust may lead to protein oxidative injury in the lung tissue of mice, which might play an important role in lung injury.

SPAG5 interacts with CEP55 and exerts oncogenic activities via PI3K/AKT pathway in hepatocellular carcinoma

Background

Deregulation of microtubules and centrosome integrity is response for the initiation and progression of human cancers. Sperm-associated antigen 5 (SPAG5) is essential for the spindle apparatus organization and chromosome segregation, but its role in hepatocellular carcinoma (HCC) remains undefined.

Methods

The expression of SPAG5 in HCC were examined in a large cohort of patients by RT-PCR, western blot and IHC. The clinical significance of SPAG5 was next determined by statistical analyses. The biological function of SPAG5 in HCC and the underlying mechanisms were investigated, using in vitro and in vivo models.

Results

Here, we demonstrated that SPAG5 exhibited pro-HCC activities via the activation of PI3K/AKT signaling pathway. SPAG5 expression was increased in HCC and correlated with poor outcomes in two independent cohorts containing 670 patients. High SPAG5 expression was associated with poor tumor differentiation, larger tumor size, advanced TNM stage, tumor vascular invasion and lymph node metastasis. In vitro and in vivo data showed that SPAG5 overexpression promoted tumor growth and metastasis, whereas SPAG5 knockdown led to the opposite phenotypes. SPAG5 interacted with centrosomal protein CEP55 to trigger the phosphorylation of AKT at Ser473. Inhibition of PI3K/AKT signaling markedly attenuated SPAG5-mediated cell growth. Furthermore, SPAG5 expression was suppressed by miR-363-3p which inhibited the activity of SPAG5 mRNA 3’UTR. Ectopic expression of SPAG5 partly abolished the miR-363-3p-caused cell cycle arrest and suppression of cell proliferation and migration.

Conclusions

Collectively, these findings indicate that SPAG5 serves a promising prognostic factor in HCC and functions as an oncogene via CEP55-mediated PI3K/AKT pathway. The newly identified miR-363-3p/SPAG5/CEP55 axis may represent a potential therapeutic target for the clinical intervention of HCC.

Electronic supplementary material

The online version of this article (10.1186/s12943-018-0872-3) contains supplementary material, which is available to authorized users.

PRAF2 expression indicates unfavorable clinical outcome in hepatocellular carcinoma

Introduction

Prenylated Rab acceptor 1 domain family member 2 (PRAF2), a novel oncogene, has been shown to be essential for the development of several human cancers; however, its role in hepatocellular carcinoma (HCC) remains unclear.

Materials and methods

PRAF2 mRNA and protein expressions were examined in fresh tissues by quantitative reverse transcription-polymerase chain reaction and Western blot, respectively, and in 518 paraffin-embedded HCC samples by immunohistochemistry. The correlation of PRAF2 expression and clinical outcomes was determined by the Student's t-test, Kaplan-Meier test, and multivariate Cox regression analysis. The role of PRAF2 in HCC was investigated by cell viability, colony formation, and migration assays in vitro and with a nude mouse model in vivo.

Results

In our study, the PRAF2 expression was noticeably increased in HCC tissues at both the mRNA and protein levels compared with that of the nontumorous tissues. Kaplan-Meier analysis indicated that high PRAF2 expression was correlated with worse overall survival in a cohort of 518 patients with HCC. The prognostic implication of PRAF2 was verified by stratified survival analysis. The multivariate Cox regression model revealed PRAF2 as an independent poor prognostic factor for overall survival (hazard ratio = 1.244, 95% CI: 1.039-1.498, P<0.017) in HCC. The in vitro data demonstrated that PRAF2 overexpression markedly enhanced cell viability, colony formation, and cell migration. Moreover, ectopic expression of PRAF2 promoted tumor growth and metastasis in vivo.

Conclusion

Collectively, we conclude that PRAF2 is increased in HCC and is a novel unfavorable biomarker for prognostic prediction for patients with HCC.

CBX8 Exhibits Oncogenic Activity via AKT/β-Catenin Activation in Hepatocellular Carcinoma

Deregulation of polycomb proteins influences the development and progression of hepatocellular carcinoma. Here we show that chromobox 8 (CBX8) expression is increased in hepatocellular carcinoma and correlates with poor outcome in two independent cohorts containing a total of 879 cases. Ectopic expression of CBX8 facilitated tumor growth and metastasis, whereas CBX8 silencing suppressed these effects. CBX8 efficiently activated AKT/β-catenin signaling via upregulation of the transcription factor EGR1 and miR-365-3p in a noncanonical manner: CBX8 directly bound the EGR1 promoter to enhance its activity. In the nucleus, CBX8 also interacted with EGR1 to prevent its degradation. Furthermore, CBX8 increased the transcription of miR-365a-3p, which promoted the nuclear localization of β-catenin by targeting the 3'-UTR ZNRF1. Inhibiting either EGR1 or miR-365a-3p partially rescued CBX8-mediated malignant phenotypes. In clinical samples, CBX8 expression closely correlated with EGR1, miR-365a-3p, and nuclear β-catenin. Collectively, our results show that CBX8 functions as an oncogene to upregulate EGR1 and miR-365-3p to stimulate the AKT/β-catenin pathway. This newly identified signaling axis may suggest new therapeutic strategies against hepatocellular carcinoma.Significance: Elucidation of a key new element of the β-catenin signaling pathway in liver cancer may suggest new therapeutic targets. Cancer Res; 78(1); 51-63. ©2017 AACR.

Increased expression of hepatocyte nuclear factor 4 alpha transcribed by promoter 2 indicates a poor prognosis in hepatocellular carcinoma

BACKGROUND

Hepatocyte nuclear factor 4 alpha (HNF4α) plays an important role in tumourigenesis. There is growing evidence indicating that HNF4α transcribed by promoter 1 (P1-HNF4α) is expressed at relatively low levels in HCC and its presence predicts a favourable outcome for hepatocellular carcinoma (HCC) patients. However, the role of HNF4α transcribed by promoter 2 (P2-HNF4α) in HCC remains unclear.

METHODS

A total of 615 HCC specimens were obtained to construct tissue microarrays and perform immunohistochemistry. The relationship between P2-HNF4α and clinical features of HCC patients were analysed. Kaplan-Meier analysis was conducted to assess the prognostic value of P2-HNF4α.

RESULTS

The results showed that the expression of P2-HNF4α in HCC was noticeably increased in HCC tissues compared with the nontumourous tissues. In addition, P1-HNF4α expression was negatively correlated with P2-HNF4α expression (p = 0.023). High P2-HNF4α expression was significantly associated with poor differentiation of HCC (p = 0.002) and vascular invasion (p = 0.017). Kaplan-Meier analysis showed that P2-HNF4α expression was closely correlated with overall survival in the training group (p = 0.01), validation group (p = 0.034), and overall group of patients with HCC (p < 0.001).

CONCLUSIONS

Our data show that the role of HNF4α in cancer development needs to be further refined. P2-HNF4α, different from P1-HNF4α, is markedly upregulated and serves as an oncogene-associated protein in HCC. Our study therefore provides a promising biomarker for prognostic prediction and a potential therapeutic target for HCC.

TRIM65 triggers β-catenin signaling via ubiquitylation of Axin1 to promote hepatocellular carcinoma

Deregulation of ubiquitin ligases contributes to the malignant progression of human cancers. Tripartite motif-containing protein 65 (TRIM65) is an E3 ubiquitin ligase and has been implicated in human diseases, but its role and clinical significance in hepatocellular carcinoma (HCC) remain unknown. Here, we showed that TRIM65 expression was increased in HCC tissues and associated with poor outcome in two independent cohorts containing 888 patients. In vitro and in vivo data demonstrated that overexpression of TRIM65 promoted cell growth and tumor metastasis, whereas knockdown of TRIM65 resulted in opposite phenotypes. Further studies revealed that TRIM65 exerted oncogenic activities via ubiquitylation of Axin1 to activate the β-catenin signaling pathway. TRIM65 directly bound to Axin1 and accelerated its degradation through ubiquitylation. Furthermore, HMGA1 was identified as an upstream regulator of TRIM65 in HCC cells. In clinical samples, TRIM65 expression was positively correlated with the expression of HMGA1 and nuclear β-catenin. Collectively, our data indicate that TRIM65 functions as an oncogene in HCC. The newly identified HMGA1/TRIM65/β-catenin axis serves as a promising prognostic factor and therapeutic target.

HBx-mediated decrease of AIM2 contributes to hepatocellular carcinoma metastasis

Tumor metastasis is responsible for the high mortality rates in patients with hepatocellular carcinoma (HCC). Absent in melanoma 2 (AIM2) has been implicated in inflammation and carcinogenesis, although its role in HCC metastasis remains unknown. In the present study, we show that AIM2 protein expression was noticeably reduced in HCC cell lines and clinical samples. A reduction in AIM2 was closely associated with higher serum AFP levels, vascular invasion, poor tumor differentiation, an incomplete tumor capsule and unfavorable postsurgical survival odds. In vitro studies demonstrated that AIM2 expression was modulated by hepatitis B virus X protein (HBx) at transcriptional and post-translational levels. HBx overexpression markedly blocked the expression of AIM2 at mRNA and protein levels by enhancing the stability of Enhancer of zeste homolog 2 (EZH2). Furthermore, HBx interacted with AIM2, resulting in an increase of AIM2 degradation via ubiquitination induction. Functionally, knockdown of AIM2 enhanced cell migration, formation of cell pseudopodium, wound healing and tumor metastasis, whereas reintroduction of AIM2 attenuated these functions. The loss of AIM2 induced the activation of epithelial-mesenchymal transition (EMT). Fibronectin 1 (FN1) was found to be a downstream effector of AIM2, with its expression reversely modulated by AIM2. Silencing of FN1 significantly halted cell migration induced by AIM2 depletion. These data demonstrate that HBx-induced loss of AIM2 is associated with poor outcomes and facilitates HCC metastasis by triggering the EMT process. The results of the present study therefore suggest that AIM2 is a potential prognostic biomarker in hepatitis B virus-related HCC, as well as a possible therapeutic target for tumor metastasis.

Zic2 promotes tumor growth and metastasis via PAK4 in hepatocellular carcinoma

The dysregulation of transcription factors contributes to the unlimited growth of cancer cells. Zic2 has been shown to be crucial to the progression of human cancers. However, its role in hepatocellular carcinoma (HCC) remains unclear. Our data showed that Zic2 expression gradually increased from normal to cancer to metastatic tissues. Zic2 overexpression promoted, whereas Zic2 knockdown inhibited, cell proliferation and migration in vitro as well as tumor growth and metastasis in vivo. Gene microarray results indicated that PAK4 was a potential target of Zic2. The knockdown of Zic2 decreased, whereas Zic2 re-expression increased, the expression of PAK4. ChIP and luciferase assays indicated that Zic2 directly bound to the PAK4 promoter and modulated its activity. PAK4 interference attenuated Zic2-mediated cell growth via modulating the Raf/MEK/ERK pathway. In a cohort of 615 patients, Zic2 was positively correlated with PAK4 and associated with worse overall and disease-free survival. Multivariate analyses revealed that Zic2 and PAK4 were independent indicators of a poor outcome in HCC. In addition, Zic2 expression was inversely correlated with miR-1271 expression. Re-introduction of miR-1271 attenuated Zic2-promoted cell proliferation and migration. Taken together, our findings suggest that the newly identified miR-1271/Zic2/PAK4 axis plays an important role in HCC progression and may serve as a potential therapeutic target for HCC.

[Influence of sodium nitrite exposure on sulfhemoglobin and hydroxyl radicals in mice]

Objective: To investigate the influence of sodium nitrite exposure on sulfhemoglobin and hydroxyl radicals in mice. Methods: A total of 60 mice were randomly divided into low-, middle-, and high-dose groups (the concentrations of sodium nitrite were 0.055 mg/ml, 0.110 mg/ml, and 0.220 mg/ml, respectively) and control group (treated with distilled water) , with 15 mice in each group (male/female ratio=1: 1) . A free-drink model was applied and the duration of exposure was 2 weeks. The body weight of all mice was recorded before exposure and at weeks 1 and 2 of exposure. At the end of exposure, the mice were treated with intraperitoneally injected sodium salicylate to capture the hydroxyl radicals and produce 2, 5-dihydroxybenzoic acid and 2, 3-dihydroxybenzoic acid, and high-performance liquid chromatography was used to measure their content. Spectrophotometry was used to measure the relative content of sulfhemoglobin. Results: At week 2 of exposure, the low-, middle-, and high-dose groups had significantly lower body weight than the control group (22.8±2.8 g/21.6±2.8 g/21.2±3.0 g vs 25.6±2.2 g, P<0.05) . The low-, middle-, and high-dose groups had a significantly higher total content of hydroxyl radicals than the control group[ (0.015 3±0.006 5) μg/ml, (0.016 4±0.017 2) μg/ml, and (0.062 7±0.091 0) μg/ml vs (0.009 ±0.007 3) μg/ml, P<0.05]. The relative content of sulfhemoglobin was 1.54%±0.73%, 2.22%±0.44%, and 2.80%±0.69%, respectively, in the low-, middle-, and high-dose groups, and the middle- and high-dose groups had a significant increase in the relative content of sulfhemoglobin compared with the control group (2.22%±0.44%/2.80%±0.69% vs 1.76%±0.60%, P<0.05) . The content of hydroxyl radicals was positively correlated with the relative content of sulfhemoglobin (r=0.837, P<0.05) . Conclusion: Sodium nitrite exposure can increase the content of sulfhemoglobin and hydroxyl radicals in blood, and there is a positive correlation between them.

Connexin 43 enhances oxaliplatin cytotoxicity in colorectal cancer cell lines

Oxaliplatin, a platinum-based chemotherapeutic agent, is an important first-line drug in the treatment of colorectal cancers, but drug resistance causes treatment failure. It has been reported that gap junctional communication can enhance the cytotoxicity of platinum drugs.  The gap junction formed of connexin proteins provides a direct pathway for electrical and metabolic cell-cell interaction. The voltage-dependent gating of gap junction allows small hydrophilic molecules and ions to permeate to adjacent cells. Connexin 43 is a diagnostic marker for cancer therapy and the predominant connexin isoform in many cell types. The purpose of this study was to investigate the role of connexin 43 in oxaliplatin activity by using colorectal cancer cell lines. LoVo and HCT116 cell lines were used for analysis. Connexin 43 expression was confirmed by western blot and immunocytochemistry. MTT, western blot, "Parachute" dye-coupling assays and reactive oxygen species measurement were used to detect cytotoxicity and the inhibition of connexin 43 expression induced by oxaliplatin. Results showed that connexin 43 enhanced oxaliplatin cytotoxicity through gap junctional communication function and high concentration of oxaliplatin inhibited connexin 43 expression to counteract its cytotoxicity. This study suggested that connexin 43 could be considered a molecular target of oxaliplatin activity in colorectal cancer.

[Influence of n-hexane on vascular endothelial active substances in brain tissue in mice]

Objective: To investigate the influence of n-hexane on vascular endothelial active substances in brain tissue in mice and its significance. Methods: A total of 48 healthy Kunming mice were randomly divided into high-dose exposure group, middle-dose exposure group, low-dose exposure group, and control group, with 12 mice in each group. All groups except the control group were exposed to n-hexane via static inhalation (0.035 g/L, 0.018 g/L, and 0.009 g/L for the high-, middle-, and low-dose exposure groups, respectively) 4 hours a day for 21 days. the mice in the control groups were not exposed to n-hexane. After the exposure, the lev-els of endothelin-1 (ET-1) , nitric oxide (NO) , and angiotensin II (Ang II) in brain tissue were measured in all groups. Results: There were significant differences in the levels of ET-1, NO, and Ang II between the three ex-posure groups and the control group (P<0.05). Compared with the control group, the high-and middle-dose expo-sure group had significant increases in the levels of ET-1 and Ang II and the high-dose exposure group had a sig-nificant reduction in the level of NO (P<0.05 or P<0.01). Conclusion: n-Hexane can affect the vascular endothe-lial active substances in brain tissue in mice, and the changes and imbalance in vascular endothelial active sub-stances may be one of the reasons for central nervous system impairment caused by n-hexane.

LRG1 expression indicates unfavorable clinical outcome in hepatocellular carcinoma

Leucine-rich-alpha-2-glycoprotein1 (LRG1) is a novel oncogene-associated protein which has been clarified vital to the progression of human cancers, but its role in hepatocellular carcinoma (HCC) remains unclear. Here, we showed that the expression of LRG1 was noticeably increased in HCC tissues, compared to the nontumorous tissues. High LRG1 expression was significantly associated with tumor size (P = 0.004), tumor differentiation (P = 0.010), TNM stage (P < 0.001) and vascular invasion (P = 0.019). Kaplan-Meier analysis showed that LRG1 expression was closely correlated to overall survival and disease-free survival in a training cohort of 474 patients with HCC. The correlation was further validated in an independent cohort of 303 HCC patients. The prognostic implication of LRG1 was confirmed by stratified survival analyses. Multivariate Cox regression model indicated LRG1 as an independent poor prognostic indicator for overall survival (Hazard ratio = 1.582, 95% confident interval: 1.345–1.862, P < 0.001) and disease-free survival (Hazard ratio = 1.280, 95% confident interval: 1.037–1.581, P = 0.022) in HCC. In vitro data showed that LRG1 markedly promoted cell migration but has no effect on cell proliferation. Collectively, our data show that LRG1 is markedly up-regulated and serves as an independent factor of poor outcomes in HCC. Our study therefore provides a promising biomarker for prognostic prediction in clinical management of HCC.

miR-634 exhibits anti-tumor activities toward hepatocellular carcinoma via Rab1A and DHX33

Deregulation of microRNAs contributes to the aberrant growth of hepatocellular carcinoma (HCC). Here, we showed that miR-634 expression was frequently decreased in HCC. Low miR-634 expression was significantly associated with larger tumor size, poorer tumor differentiation, advanced TNM stage, vascular invasion, absence of tumor capsule and unfavorable overall survival. Overexpression of miR-634 markedly attenuated cell viability, colony formation, tumor growth and metastasis, whereas miR-634 inhibition resulted in the opposite phenotypes. Furthermore, re-introduction of miR-634 induced cell apoptosis in vitro and in vivo. Mechanistically, miR-634 inhibited the expression of Rab1A and DHX33 via directly binding to the 3'-UTR of both genes. In clinical samples, the expression of Rab1A or DHX33 was reversely correlated with miR-634. Re-expression of Rab1A or DHX33 abrogated the miR-634-mediated inhibition of cell proliferation and migration. Collectively, our data suggest a tumor suppressor role of miR-634 in HCC. The newly identified miR-634/Rab1A or miR-634/DHX33 axis serves as a potential therapeutic target for the clinical management.

[Effects of expression of calpain mRNA in rabbits exposed to vibration by hind legs]

OBJECTIVE

To study the effects of expression of calpain mRNA in rabbits exposed to vibration by hind legs.

METHODS

32 New Zealand rabbits were randomly divided into a control group and 3 experimental groups according to 4-hour energy-equivalent frequency-weighted acceleration[ahw (4)]: low (4.33 m/s(2)) , moderate (8.67 m/s(2)) and high (17.34 m/s(2)) intensity group to accepted the vibration by hind legs. 45 ds later, brain and skeletal muscle tissue of rabbits were taken to detect the expression of calpain-1 and calpain-2 mRNA by RT-qPCR technique.

RESULTS

The relative content of calpain-1 mRNA in the brain tissues in rabbits of low, medium and high intensity group were 8.35±3.75,9.64±4.54,5.10±5.26. While the relative content of calpain-2 mRNA in the brain tissues in rabbits of low, medium and high intensity group were 7.34±4.97,8.50±5.66, 8.16±5.59. Compared with the control group (1.10±0.29, 0.56±0.43) , the expression of calpain-1 and calpain-2 mRNA of the intensity groups showed an significantly increasing trend (P<0.01). In skeletal muscle tissue, the relative content of calpain-1 mRNA were 4.36±2.05, 7.37±4.06, 12.46±6.21.Compared with the control group (0.98±0.59) , the expression of calpain-1 mRNA of experiment groups were significantly higher (P<0.05) .The expression of calpain-2 mRNA of the intensity groups had no significantly difference with the control group (P>0.05).

CONCLUSION

The expression of calpain-1 and calpain-2 mRNA can be promoted by the vibration by the hind legs.

Co-suppression of vitamin C composite nano-drug carrier and its drug delivery to nidus in tumor cells

This study aimed to discuss the co-suppression of vitamin C-contained composite nano-drug carrier and its drug delivery to nidus in tumor cells. Amphiphilic polymers PLA-block-PAAA and block polymer PLA-PEG4000-Maleimide, PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelles were prepared, and, PLA-block-PAAA polymer-coated Nile red nano-micelle, PLA-block-PAA and PLA-PEG4000-Maleimide composite nano-micelles as well as paclitaxel-carrying composite nano-micelle in different molar ratios were given stability tests. Lastly, PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelle cancer cells and paclitaxel-carrying composite nano-micelle cancer cells were given toxicity tests. Stability tests showed that self stability of PLA-block-PAAA (63/8) nano-micelle was not sufficient; the stability was good when the molar ratio of PLA-block-PAAA and PLA-PEG4000-Maleimide composite nano-micelle was 3:1; paclitaxel-carrying composite nano-micelle had good stability within 48 hours; PAAA segment had an inhibiting effect on C6 cancer cells and paclitaxel-carrying composite nano-micelle had a strong inhibiting effect also on tumors. After 24 hours, with the continuous release of paclitaxel, the tumor inhibiting effect of paclitaxel-carrying composite nano-micelle enhanced gradually, and the controlled-release of drugs had continuous inhibiting effect on tumor cells. Therefore, PAAA segment and paclitaxel had time-postponed synergistic effect. In conclusion, vitamin C-contained composite nanometer drug carrier materials can deliver anti-cancer drugs to nidus and thus inhibit tumor cells.

FoxD3-regulated microRNA-137 suppresses tumour growth and metastasis in human hepatocellular carcinoma by targeting AKT2

microRNAs, frequently deregulated in human cancer, have been implicated in the progression of hepatocarcinogenesis. Here, we show that microRNA (miR)-137 is significantly down-regulated in hepatocellular carcinoma (HCC). Its decreased expression is associated with vein invasion, incomplete Involucrum, and distant metastasis. Multivariate analysis suggests that miR-137 is an independent indicator for poor survival. We next show that over-expression of miR-137 suppresses cell proliferation, migration and invasion in vitro. Conversely, miR-137 inhibition promotes HCC cell growth. We also identify AKT2 as a key target of miR-137 in this context. Statistical data reveal a reverse correlation of AKT2 and miR-137 expression in HCC patients. Silencing of AKT2 phenotypically copied miR-137-induced phenotypes, whereas re-expression of AKT2 reversed the suppressive effects of miR-137. Further investigations showed that miR-137 exerted its anti-tumour activity via inhibiting the AKT2/mTOR pathway. Moreover, we demonstrate that FoxD3 directly binds to the promoter of miR-137 and activates its transcription. In vivo studies confirm that FoxD3-regulated miR-137 inhibited HCC growth and metastasis via targeting AKT2. Together, our findings indicate that miR-137 is a valuable biomarker for HCC prognosis and the FoxD3/miR-137/AKT2 regulatory network plays an important role in HCC progression.

Decrease of Bcl-xL/Bcl-2-associated death promoter in hepatocellular carcinoma indicates poor prognosis

Bcl-xL/Bcl-2-associated death promoter (Bad) is a proapoptotic member of Bcl-2 family and plays a key role in tumor development. To explore the expression of Bad and its clinical significance in hepatocellular carcinoma (HCC), we analyzed a large cohort of 437 HCC samples by tissue microarray (TMA)-based immunohistochemistry. Our data showed that Bad expression was markedly decreased in 50.6% (221/437) of HCC tissues, compared with the adjacent nontumorous tissues. Bad expression was closely associated with adverse clinical characters such as clinical stage (P=0.007), tumor size (P=0.008), vascular invasion (P=0.024), tumor differentiation (P=0.018) and AFP level (P=0.039). Furthermore, Kaplan-Meier analysis indicated that low Bad expression was significantly correlated to overall survival (P<0.0001) but not disease-free survival (P=0.587) and recurrence-free survival (P=0.707) of patients with HCC. Stratified survival analysis further confirmed the prognostic value of Bad. Moreover, multivariate analyses revealed that Bad was an independent indicator of overall survival in HCC (hazard ration=0.589, 95% confidence interval: 0.483-0.717, P<0.0001). Collectively, our data suggest that Bad is down-regulated in HCC and serves as a promising biomarker for poor prognosis of patients with this fatal disease.

Pyruvate kinase M2 prevents apoptosis via modulating Bim stability and associates with poor outcome in hepatocellular carcinoma

Pyruvate kinase M2 (PKM2) contributes to the Warburg effect, a hallmark of cancer. We showed that PKM2 levels were correlated with overall survival (hazard ration = 1.675, 95% confidence interval: 1.389-2.019, P < 0.001) and disease-free survival (hazard ration = 1.573, 95% confidence interval: 1.214-2.038, P < 0.001) in a cohort of 490 patients with HCC. The correlations were further validated in an independent cohort of 148 HCC patients. Multivariate analyses revealed that PKM2 was an independent indicator of poor outcome in HCC. The knockdown of PKM2 in HCC cells inhibited cell proliferation and induced apoptosis in vitro and in vivo. Bim siRNA markedly abolished the PKM2-depletion-induced apoptosis. PKM2 depletion decreased the degradation of Bim. In clinical samples, PKM2 expression was reversely correlated with Bim expression. Combination of PKM2 and Bim levels had the best prognostic significance. We suggest that PKM2 serves as a promising biomarker for poor prognosis of patients with HCC and its knockdown induces HCC apoptosis by stabilizing Bim.

Abstract 3547: FoxD3-regulated microRNA-137 suppresses tumour growth and metastasis in human hepatocellular carcinoma by targeting AKT2

Background and Aims: microRNAs, which are frequently deregulated in human cancer, have been implicated in the progression of hepatocarcinogenesis. Our study aims to investigate the role of miR-137 in cell proliferation and metastasis of hepatocellular carcinoma and the underlying molecular mechanisms.

Methods: Real-time PCR and western blot were used to examine the expressions of miR-137, Akt2 and FoxD3 in HCC tissues and cells. The in vitro and in vivo effects of miR-137 were determined. Luciferase reporter assay was conducted to confirm the association of miR-137 and AKT2. CHIP assay was performed to test the regulation of miR-137 by FoxD3.

Results: We show that microRNA (miR)-137 is significantly down-regulated in hepatocellular carcinoma (HCC), and its decreased expression is associated with vein invasion, incomplete Involucrum, and tumour metastasis. Multivariate analysis suggests that miR-137 is an independent indicator for poor survival. To determine its role in HCC development, we showed that overexpression of miR-137 suppresses cell proliferation, invasion and metastasis in vitro. Conversely, miR-137 inhibition promoted HCC cell growth. We also identified AKT2 as a key target of miR-137 in this context. Statistical data revealed a reverse correlation of AKT2 and miR-137 expression in HCC patients. Silencing of AKT2 phenotypically copied miR-137-induced phenotypes, whereas re-expression of AKT2 reversed the suppressive effects of miR-137. Further investigation showed that miR-137 exerted its anti-tumour activity via inhibiting the AKT2/mTOR pathway. Moreover, we demonstrated that FoxD3 binds to the promoter of miR-137 and activates its transcription. In vivo studies confirmed that FoxD3-regulated miR-137 inhibition of HCC growth and metastasis via directly targeting AKT2.

Conclusions: Our findings indicated that miR-137 is a valuable biomarker for HCC prognosis and demonstrated that the FoxD3/miR-137/AKT2 regulatory network plays an important role in HCC progression.

Citation Format: Li-Li Liu, Shi-Xun Lu, Min Li, Jia Fu, Chris Zhiyi Zhang, Jing-Ping Yun. FoxD3-regulated microRNA-137 suppresses tumour growth and metastasis in human hepatocellular carcinoma by targeting AKT2. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3547. doi:10.1158/1538-7445.AM2014-3547

Momordica charantia lectin exhibits antitumor activity towards hepatocellular carcinoma

BACKGROUND

The incidence and mortality of hepatocellular carcinoma (HCC) remain high worldwide. Drug screening from natural plants is one of the potential therapeutic approaches on HCC.

METHODS

The antitumor effect of momordica charantia lectin (MCL) was examined, using MTT, colony formation, AnnexinV/PI staining, western blot and animal model.

RESULTS

MCL treatment induced G2/M phase arrest, autophagy, DNA fragmentation, mitochondrial injury, and subsequently cell apoptosis in HCC cells. Activation of caspase and MAPK pathway was involved in MCL-induced apoptosis. In vitro and in vivo studies showed that up-regulation of truncated Bid (tBid) upon MCL treatment. Correlation analysis revealed that Bid expression was reversely associated with the IC50 of MCL. Bid suppression using Bid siRNA, BI-6C9 (Bid inhibitor) and Z-IETD-FMK (caspase 8 inhibitor) dramatically attenuated MCL-induced cell proliferation inhibition, caspase 3 activation, ΔΨm depolarization and apoptosis. In addition, combination of MCL and sorafenib exerted stronger lethal activity towards HCC in vitro and in vivo.

CONCLUSION

Our data show that the natural compound MCL manifests antitumor activities towards HCC and therefore suggest MCL as a promising chemotherapeutic agent.

miR-625 suppresses tumour migration and invasion by targeting IGF2BP1 in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most prevalent malignancies and the third leading cause of cancer-related deaths worldwide. Tumour metastasis is one of the major causes of high mortality. microRNAshave been implicated in HCC metastasis. In this study, we found that miR-625 was frequently downregulated in HCC samples. A decrease in miR-625 was significantly correlated with lymph node anddistance metastasis (P=0.013), the presence of portal venous invasion (P=0.036), tumor-node-metastasis (TNM) stage (P=0.027) and unfavourable overall survival (P=0.003). Compared with primary tumours, miR-625 expression was markedly reduced in portal venous metastatic tumours. Re-expression of miR-625 in HCC cells was remarkably effective in suppressing cell migration andinvasiveness in vitro and in vivo. Mechanistically, miR-625 was confirmed to downregulate IGF2 mRNA-binding protein 1(IGF2BP1) directly, the expression of which was inversely correlated with the level of miR-625 in HCC cell lines and tissues. High expression of IGF2BP1 was frequently found in HCC samples, and associated with poor prognosis. Knockdown of endogenous IGF2BP1 by siRNA exhibited similar effects as the overexpression of miR-625, whereas overexpression of IGF2BP1 (without the 3'-UTR) abrogated miR-625-mediated metastasis inhibition. Interference of the PTEN/HSP27 pathway contributed to miR-625-mediated metastasis inhibition. Taken together, our data suggest that miR-625 might function as an antimetastatic miRNA to have an important role in HCC progression by modulating the IGF2BP1/PTEN pathway. The newly identified miR-625/IGF2BP1 axis represents a new potential therapeutic target for HCC treatment.

Genetic polymorphisms of CCND1 and PTEN in progression of esophageal squamous carcinoma

Cyclin D1 (CCND1) plays a significant role in G1-S transition of cell cycle, and phosphatase and a tensin homologue (PTEN) negatively regulate cell cycle through phosphatidylinositol 3-kinase (PI3K)/AKT signaling. CCND1 and PTEN genetic polymorphisms might induce susceptibility to the occurrence of esophageal squamous cell carcinoma (ESCC). Three hundred and four ESCC patients and 413 healthy controls from Anyang, China, were enrolled in this study. All genotyping at CCND1 (807 G/A) and PTEN (rs701848 T/C and rs2735343 C/G) were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay. Unconditional logistic regression model was used to analyze the correlation between the polymorphisms and the susceptibility to develop ESCC. Statistically significant differences were observed between cases and controls in distribution of genotypes or alleles at PTEN rs701848 T/C and rs2735343 C/G, with either haplotype TG or CG possessing notably higher proportion in cases than in the controls. However, such difference could not be found in the distribution of the polymorphisms at CCND1 807 G/A. In summary, the polymorphisms of PTEN rs701848 T/C and rs2735343 C/G might represent crucial modifying factors for development of ESCC.

Decrease of fibulin-3 in hepatocellular carcinoma indicates poor prognosis

Fibulin-3, originally identified in senescent and Werner syndrome fibroblasts, has been implicated in cell morphology, growth, adhesion and motility. Fibulin-3 exhibits both antitumor and oncogenic activities towards human cancers; however, the role of Fibulin-3 in hepatocellular carcinoma (HCC) remains elusive. In this study, we showed that both the mRNA and protein levels of Fibulin-3 were remarkably downregulated in HCC cell lines and fresh tissues. Immunohistochemical data revealed that Fibulin-3 was decreased in tumorous tissues in 67.1% (171/255) of cases compared to the corresponding adjacent nontumorous tissues. The results of statistical analysis indicated that low Fibulin-3 expression, defined by the receiver operating characteristic curve (ROC), was significantly associated with tumor differentiation (P=0.008), clinical stage (P=0.014) and serum AFP levels (P<0.01). Furthermore, Kaplan-Meier and multivariate analysis suggested that Fibulin-3 is an independent negative prognostic indicator for both overall (P<0.001) and recurrence-free (P=0.036) survival. In addition, an in vitro study demonstrated that knockdown of Fibulin-3 by siRNA markedly increased cell viability and promoted cell invasion in HCC cells. Collectively, our data suggest that Fibulin-3 exhibits antitumor effects towards HCC and serves as a biomarker of unfavorable prognosis for this deadly disease.

Low cyclin F expression in hepatocellular carcinoma associates with poor differentiation and unfavorable prognosis

Cyclin F, capable of forming Skp1-Cul1-F-box protein ubiquitin ligase complex, is implicated in controlling centrosome duplication and preventing genome instability. Cyclin F oscillates during cell cycle with a similar pattern to cyclin A. However, its expression and significance in cancer remain obscure. In this study, we showed that cyclin F was noticeably decreased in 16 pairs of tissue samples of hepatocellular carcinoma (HCC) compared to paracarcinoma tissues, at both mRNA and protein levels. Immunohistochemical staining data revealed that in 71.8% (176/245) of HCC cases, cyclin F expression in tumor tissue was much lower than that in nontumorous tissue. Low cyclin F expression, defined by receiver operating characteristic curve analysis, was present in 69.0% of HCC patients. Low expression of cyclin F was significantly correlated with tumor size, clinical stage, serum alpha-fetoprotein level and tumor multiplicity. Further study showed that cyclin F expression was reversely associated with tumor differentiation in HCC. Kaplan-Meier analysis indicated that low cyclin F expression was related to poor overall survival and recurrence-free survival. The prognostic impact of cyclin F was further confirmed by stratified survival analysis. Importantly, multivariate analysis revealed that low cyclin F expression was an independent poor prognostic marker for overall survival. We conclude that cyclin F is downregulated in HCC and is a promising prognostic marker for patients suffering from this deadly disease.

Potential implication of activating killer cell immunoglobulin-like receptor and HLA in onset of pulmonary tuberculosis

Killer cell immunoglobulin-like receptor (KIR) and human leucocyte antigen (HLA) play crucial role in maintaining immune homoeostasis and controlling immune responses. To investigate the influence of KIR and HLA-C ligands on the risk of pulmonary tuberculosis (PTB), we studied 200 patients who were confirmed to have PTB and 200 healthy controls on the different frequencies of KIR and HLA-C ligands. Genotyping of these genes was conducted by sequence-specific primer polymerase chain reaction (SSP-PCR) method. Gene frequencies were compared between PTB group and the control group by χ(2) test, and P < 0.05 was regarded as statistically significant. As a result, the frequency of KIR genotype A/B was increased in PTB than controls but A/A was decreased. Moreover, striking differences were observed in the frequencies of HLA-Cw*08 between the two groups. Besides, the frequencies of '2DL2/3 with C1' in PTB were increased compared with control group. In addition, individuals with no KIR2DS3 and no Cw*08 were higher in controls than in PTB. KIR2DS1 was increased in PTB when HLA-C group 2 alleles were missing. In conclusion, KIR and HLA-C gene polymorphisms were related to susceptibility to PTB.

Low SIRT3 expression correlates with poor differentiation and unfavorable prognosis in primary hepatocellular carcinoma

SIRT3, a mitochondrial sirtuin belonging to nicotinamide adenine nucleotide (NAD) dependent deacetylases, is implicated in metabolism, longevity and carcinogenesis. SIRT3 expression and its significance in hepatocellular carcinoma (HCC) remain largely unclear. In this study, we demonstrated that SIRT3 expression in HCC tissue was much lower than that in paracarcinoma tissue, at both mRNA and protein levels. The cutoff value for low SIRT3 expression in HCC was defined according to receiver operating characteristic curve (ROC) analysis. As disclosed by immunohistochemistry (IHC) results, low SIRT3 expression was present in 67.3% (167/248) of HCC cases. Furthermore, low expression of SIRT3 was significantly correlated to differentiation (P = 0.013), clinical stage (P = 0.005), serum AFP level (P<0.01), tumor multiplicity (P = 0.026) and relapse (P = 0.028). Moreover, Kaplan-Meier analysis indicated that low SIRT3 expression associated with unfavorable overall survival (P<0.01) and recurrence-free survival (P = 0.004). The prognostic impact of SIRT3 was further confirmed by stratified survival analysis. Importantly, multivariate analysis revealed that low SIRT3 expression was an independent poor prognostic marker for overall survival (Hazard Ratio (HR) 0.555, 95% confidence interval (95% CI) 0.344–0.897, P = 0.016). Collectively, we conclude that SIRT3 is decreased in HCC and is a novel unfavorable marker for prognosis of patients with this fatal disease.

Downregulation of polo-like kinase 4 in hepatocellular carcinoma associates with poor prognosis

Polo-like kinase 4 (PLK4), belonging to serine/threonine kinase family, is critical for centriole replication and cell cycle progression. PLK4 has been proposed as a tumor suppressor in hepatocellular carcinoma (HCC). However, its expression and significance in HCC have not been well studied. In the present study, we found that PLK4 was markedly downregulated in both HCC cell lines and fresh cancer tissues, using quantitative real-time-PCR and western blot. Immunohistochemistry data also revealed that decreased expression of PLK4 was present in 72.4% (178/246) of HCC tissues, compared with the corresponding adjacent nontumorous tissues. Furthermore, PLK4 expression significantly correlated with clinicopathological parameters, including clinical stage (P=0.034), serum α-fetoprotein (AFP) (P=0.019) and tumor size (P=0.032). Moreover, HCC patients with low PLK4 expression survived shorter than those with high PLK4 expression, as indicated by overall survival (P=0.002) and disease-free survival (P=0.012) assessed by the Kaplan-Meier method. In addition, multivariate analysis suggested PLK4 as an independent predictor of overall survival (HR, 0.556; 95%CI, 0.376-0.822; P=0.003) and disease-free survival (HR, 0.547; 95%CI, 0.382-0.783; P=0.001). Collectively, our study demonstrated that PLK4 was remarkably downregulated in HCC and could be served as a potential prognostic marker for patients with this deadly disease.

Molecular characterization of amelogenesis imperfecta in Chinese patients

BACKGROUND

Mutations in 6 genes have been identified as being part of the etiology of amelogenesis imperfecta (AI) with various phenotypes in an isolated condition. Among them the FAM83H gene is the major contributor to the etiology of AI with unknown function.

OBJECTIVE

This study aims to determine the phenotypic and molecular characterization of Chinese AI patients and to analyze the structure and function of the FAM83H protein.

METHODS

We enrolled 6 hypocalcified AI and 3 hypoplastic AI families from the Chinese population. Mutation analysis was performed by amplifying and sequencing all exons including intron-exon borders for FAM83H and ENAM genes. Structural modeling and function analysis on the FAM83H protein were carried out by bioinformatic processing.

RESULTS

No obvious anterior open bite was observed in all the investigated individuals. Five mutations (c.906T>G, c.924dupT, c.973C>T, c.1354C>T and c.2029C>T) in the C-terminal of the FAM83H gene were revealed, respectively, in 5 out of 6 hypocalcified AI families, and a splicing mutation c.534 + 1G>A in the ENAM gene was identified in 1 out of 3 hypoplastic AI families. Structural models of the N- and C-terminal regions of FAM83H were generated by homology modeling. The predicted structure of the FAM83H N-terminal shows resemblance to that of glycosyltransferases with GT-A folds, and the predicted structure of the FAM83H C-terminal possesses similarity to type I collagen protein.

CONCLUSIONS

To our knowledge, this is the first report of AI with specific molecular variations in families of Chinese descent. Our study provides new insights into the structure and function of the FAM83H protein.

Dihydroartemisinin exhibits antitumor activity toward hepatocellular carcinoma in vitro and in vivo

Dihydroartemisinin (DHA), a semi-synthetic derivative of artemisinin isolated from the traditional Chinese herb Artemisia annua L., has been shown to exhibit inhibitory effects on human cancer cells. However, its antitumor ability toward hepatocellular carcinoma (HCC) has not been studied. In this study, we demonstrated that DHA significantly inhibited HCC cell growth in vitro and in vivo via inducing G2/M cell cycle arrest and apoptosis. The induction of p21 and the inhibition of cyclin B and CDC25C contributed to DHA-induced G2/M arrest. DHA-induced apoptosis was associated with mitochondrial membrane depolarization, release of cytochrome c, activation of caspases, and DNA fragmentation. Activation of caspase 9 and caspase 3, but not caspase 8, was detected in DHA-treated cells. Attenuation of apoptosis in cells pretreated with Z-VAD-FMK suggested the involvement of caspase cascade. Furthermore, p53 facilitated apoptosis caused by DHA. Bcl-2 family proteins were also responsible for DHA-induced apoptosis. DHA exposure decreased Mcl-1 expression but increased the levels of Noxa and active Bak. Bak was released from the Mcl-1/Bak complex due to the decline of Mcl-1. Further study revealed that Mcl-1 was rapidly degraded in DHA-treated cells and that DHA-induced apoptosis was largely inhibited by overexpression of Mcl-1 or RNAi-mediated decrease of Bak and Noxa. In a HCC-xenograft mouse model, the intraperitoneal injection of DHA resulted in significant inhibition of HCC xenograft tumors. Taken together, our data, for the first time, demonstrate the potential antitumor activity of DHA in HCC.

Cobrotoxin-containing analgesic compound to treat chronic moderate to severe cancer pain: results from a randomized, double-blind, cross-over study and from an open-label study

Cobrotoxin produces intense analgesia but it has an onset of response of 1-3 h which hampers its clinical use in cancer pain. Recently, a compound analgesic formulation combining cobrotoxin, tramadol hydrochloride and ibuprofen (Compound Keluoqu, CKLQ) has become available in China. The aim of this study was to evaluate the clinical efficacy of CKLQ for moderate to severe cancer pain. A consecutive series of patients with chronic moderate to severe cancer pain was enrolled into two multicenter trials. Of the 230 eligible patients, 119 were assigned to a randomized, double-blind, cross-over study, while 111 entered an open-label study. They were all of Han-China nationality and had a mean age of 52.0 and 55.4 years and a mean body weight of 55.6 and 52.9 kg, respectively. A total of 11 patients discontinued the study, 6 (54.5%) because of insufficient pain relief and 5 due to the occurrence of adverse events. In the cross-over study, 59 patients were randomized to receive a CKLQ package with 2 CKLQ tablets (each containing 0.16 mg cobrotoxin, 25 mg tramadol hydrochloride and 50 mg ibuprofen) and 2 placebo capsules, a placebo package with 2 placebo tablets and 2 placebo capsules, and an active control package with 2 tramadol hydrochloride capsules (each containing 50 mg tramadol hydrochloride) and 2 placebo tablets (arm A), and 60 to receive a tramadol hydrochloride package, a placebo package and a CKLQ package (arm B), sequentially and only once. Patients in the open-label study only received CKLQ and were given the option to continue for up to 7 days as long as they had satisfactory pain relief. Pain response was classified as CR, PR and NC. CR was defined as 100% pain relief, with a pain score of 0 on a 0-10 VAS. PR was defined as decreased to mild pain, with a pain score of no more than 4 on a 0-10 VAS. NC was defined as pain that either remained unchanged or that was reduced from severe to moderate at baseline, with a VAS pain score of more than 4 after treatment. One hundred and eight patients completed the cross-over study with all the three drug units. The overall rate of pain relief was 93/111 (83.7%) for CKLQ, 75/110 (68.2%) for tramadol hydrochloride (P=0.011) and 39/111 (35.1%) for placebo (P<0.001). The mean duration of pain relief with CKLQ was significantly longer than that of the other two agents (P<0.001). Of the 35 patients who did not respond to tramadol hydrochloride, 27 (77.1%) responded to CKLQ, while of the 18 who did not respond to CKLQ, 8 (55.6%) achieved satisfactory pain control with tramadol hydrochloride. In the open-label study, the overall relief rate of a single-dose of CKLQ was 99/111 (89.2%). A reduction in the percentage of complete relief, an increase in that of PR and a significant decrease in duration of relief were observed after continuous treatment with at least 10 doses of CKLQ. The frequency of adverse events for CKLQ was similar to that of tramadol hydrochloride. The results of the randomized, double-blind, cross-over study and the open-label study of CKLQ in cancer patients with chronic moderate to severe cancer pain suggest that the CKLQ may be valuable for the treatment of chronic moderate to severe cancer pain. However, the tolerance of CKLQ remains to be further defined.

Distribution and expression of recombinant plasmid encoding chicken interleukin-2

A plasmid DNA that encodes chicken interleukin-2 (pCI-ChIL-2-EGFP) was investigated for its distribution and expression after intramuscular (i.m.) injection in chickens. After the i.m. injection, serum distribution was detectable from 2 h post inoculation (p.i.), peaked at 8 h p.i., and disappeared at 7 days p.i. The plasmid DNA was also observed in several organs including heart, liver, lung, spleen, bursa and inoculated muscle at different time points, but at 19 days p.i. the plasmid DNA was not found in any organ except inoculated muscle. Fluorescence of enhanced green fluorescent protein (EGFP) was found in cytoplasm and nucleus of cultured Vero cells, chicken embryo fibroblasts and peripheral blood lymphocytes, which were transfected in vitro with the plasmid DNA or in vivo with Lipofectamine. The expression profile of the fusion gene (ChIL-2-EGFP) in vivo was measured by RT-PCR, ELISA and fluorescence microscopy. The EGFP expression was detected from 8 h p.i. to 14 days p.i. and peaked at 5 days p.i., when the number of EGFP-expression myocytes was about 5% in the injected site. These results demonstrate that intramuscular administration of plasmid DNA leads to widespread distribution and long-term expression in vivo.