Clinical atlas of rectal cancer highlights the barriers and insufficient interventions underlying the unfavorable outcomes in older patients.

Background: Aging confers an increased risk of developing cancer, and the global burden of cancer is cumulating as human longevity increases. Providing adequate care for old patients with rectal cancer is challenging and complex. Method: A total of 428 and 44,788 patients diagnosed with non-metastatic rectal cancer from a referral tertiary care center (SYSU cohort) and the Surveillance Epidemiology and End Results database (SEER cohort) were included. Patients were categorized into old (over 65 years) and young (aged 50-65 years) groups. An age-specific clinical atlas of rectal cancer was generated, including the demographic and clinicopathological features, molecular profiles, treatment strategies, and clinical outcomes. Results: Old and young patients were similar in clinicopathological risk factors and molecular features, including TNM stage, tumor location, tumor differentiation, tumor morphology, lymphovascular invasion, and perineural invasion. However, old patients had significantly worse nutritional status and more comorbidities than young patients. In addition, old age was independently associated with less systemic cancer treatment (adjusted odds ratio 0.294 [95% CI 0.184-0.463, P < 0.001]). We found that old patients had significantly worse overall survival (OS) outcomes in both SYSU (P < 0.001) and SEER (P < 0.001) cohorts. Moreover, the death and recurrence risk of old patients in the subgroup not receiving chemo/radiotherapy (P < 0.001 for OS, and P = 0.046 for time to recurrence [TTR]) reverted into no significant risk in the subgroup receiving chemo/radiotherapy. Conclusions: Although old patients had similar tumor features to young patients, they had unfavorable survival outcomes associated with insufficient cancer care from old age. Specific trials with comprehensive geriatric assessment for old patients are needed to identify the optimal treatment regimens and improve unmet cancer care. Study registration: The study was registered on the research registry with the identifier of researchregistry 7635.

Deregulation of Cholesterol Homeostasis by a Nuclear Hormone Receptor Crosstalk in Advanced Prostate Cancer.

Metastatic castration-resistant prostate cancer (mCRPC) features high intratumoral cholesterol levels, due to aberrant regulation of cholesterol homeostasis. However, the underlying mechanisms are still poorly understood. The retinoid acid receptor-related orphan receptor gamma (RORγ), an attractive therapeutic target for cancer and autoimmune diseases, is strongly implicated in prostate cancer progression. We demonstrate in this study that in mCRPC cells and tumors, RORγ plays a crucial role in deregulation of cholesterol homeostasis. First, we found that RORγ activates the expression of key cholesterol biosynthesis proteins, including HMGCS1, HMGCR, and SQLE. Interestingly, we also found that RORγ inhibition induces cholesterol efflux gene program including ABCA1, ABCG1 and ApoA1. Our further studies revealed that liver X receptors (LXRα and LXRß), the master regulators of cholesterol efflux pathway, mediate the function of RORγ in repression of cholesterol efflux. Finally, we demonstrated that RORγ antagonist in combination with statins has synergistic effect in killing mCRPC cells through blocking statin-induced feedback induction of cholesterol biosynthesis program and that the combination treatment also elicits stronger anti-tumor effects than either alone. Altogether, our work revealed that in mCRPC, RORγ contributes to aberrant cholesterol homeostasis by induction of cholesterol biosynthesis program and suppression of cholesterol efflux genes. Our findings support a therapeutic strategy of targeting RORγ alone or in combination with statin for effective treatment of mCRPC.

Quasisynchronization for Neural Networks With Partial Constrained State Information via Intermittent Control Approach.

This work addresses quasisynchronization (QS) of the master-slave (MS) neural networks (NNs) with mismatched parameters. The logarithmic quantizer and the round-robin protocol (RRP) are used to deal with the limited communication channel (CC) capacity, then the intermittent control strategy is employed to improve the efficiency of CC and the controller. A transmission-dependent controller is designed, and the synchronization error system (SES) is established. The QS with a boundary is ensured for the MS NNs by a developed sufficient condition, and the controller design method is given. A numerical simulation is given to show the effectiveness of the obtained method.

Consensus-based distributed receding horizon estimation.

This paper studies the distributed state estimation over sensor networks based on receding horizon estimation (RHE). Firstly, a new scheme of centralized RHE is introduced, which gathers the decomposition terms instead of collecting the measurements of each node. Then, we present a distributed estimate algorithm based on the centralized RHE. To avoid the quadratic programming (QP) problem, the proposed algorithm takes advantage of the analytical solution of the centralized RHE and performs consensus steps to generalize the distributed estimation for each node, which greatly reduces each node's computation. Under the assumption of collective observability over networks, the proposed algorithm can guarantee the stability of estimation error in the case of enough consensus steps. Finally, the simulation results verify the effectiveness of the proposed method.

The Addition of Preoperative Radiation Is Insufficient for Lateral Pelvic Control in a Subgroup of Patients With Low Locally Advanced Rectal Cancer: A Post Hoc Study of a Randomized Controlled Trial.

BACKGROUND: The local recurrence of rectal cancer has been improved by total mesorectal excision following neoadjuvant chemoradiotherapy. However, in patients with low locally advanced rectal cancer, lateral pelvic recurrence remains to be addressed. OBJECTIVE: This study aimed to determine the efficiency of neoadjuvant radiotherapy in addressing lateral pelvic recurrence and which subgroup of patients might be optimal to receive lateral lymph node dissection. DESIGN: The MRI/CT images were reassessed for lateral lymph node status. The lateral lymph nodes with short axis ≥5 mm and ≥4 mm were considered positive in pretreatment and restaging MRI/CT. SETTING: This was a post hoc analysis of a prospective randomized controlled trial (FOWARC, NCT01211210). PATIENTS: A total of 495 patients with stage II or III rectal adenocarcinoma were included in the original trial. According to the excluding criteria, the finally included population consists of 253 patients; of these, 195 patients received neoadjuvant chemoradiotherapy and 94 received chemotherapy alone. MAIN OUTCOMES AND MEASURES: The primary outcome was the 5-year lateral pelvic recurrence rate. RESULTS: Compared with patients receiving chemotherapy alone, patients receiving additional radiotherapy had a marginal significance of lower lateral pelvic recurrence rate (6.6% vs 13.0%; p = 0.051). In the subset with pretreatment positive lateral lymph nodes, patients had a lateral pelvic recurrence rate of 22.6% and 45.1% after neoadjuvant chemoradiotherapy and chemotherapy alone. Of note, 34.9% of the pretreatment positive lateral lymph nodes were persistent after neoadjuvant chemoradiotherapy, culminating in a lateral pelvic recurrence rate of 63.3%. LIMITATIONS: This is a post hoc analysis, and only the patients from the leading center were included, which limited the sample size. In addition, the lateral lymph node dissection was not performed in this cohort. CONCLUSIONS: The addition of radiotherapy in neoadjuvant regimens could not address lateral pelvic recurrence adequately. Some subgroups of patients might need additional dissection. See Video Abstract at http://links.lww.com/DCR/B613. LA INCLUSION DE LA RADIOTERAPIA PREOPERATORIA ES INSUFICIIENTE EN EL CONTROL PLVICO LATERAL EN UN SUBGRUPO DE PACIENTES CON CNCER DE RECTO INFERIOR LOCALMENTE AVANZADO UN ESTUDIO POSTHOC CONTROLADO Y RANDOMIZADO: ANTECEDENTES:La recurrencia local del cancer de recto ha disminuido al efectuar una excision mesorrectal total seguida de quimioradioterapia neoadyuvante. No obstante, en pacientes con cancer de tercio inferior de recto avanzado localmente, aún está por controlarse la recurrencia pélvicaOBJETIVOS:Determinar la eficacia de la radioterapia neoadyuvante en el control de la recurrencia pélvica lateral y en que subgrupo de pacientes sería conveniente efecutar una excisión lateral de las cadenas ganglionares.DISEÑO:Se reevaluaron las imágenes tomográficas y de resonancia magnética del status de las cadenas ganglionares linfáticas laterales. Los ganglios linfáticos laterales con un eje-corto > 5 mm y ≥ 4 mm se consideraron como positivos previo al tratamiento y reestadificados con RM y TAC respectivamente.ESCENARIO:Es un análisis post hoc de un studio prospectivo randomizado controlado (FOWARC, NCT01211210).PACIENTESSe incluyeron un total de 495 pacientes en estdio II o III con adenomcarcinoma rectal en el estudio original. De acuerdo a los criterios de exclusión, la población final incluida consistió en 253 pacientes; de estos, 195 recibieron quimioradioterapia neoadyuvante y 94 quimioterapia sola.EVALUACION DE LOS RESULTADOS PRINCIPALES:El parámetro mas importante fue la tasa de recurrencia pélvica lateral a cinco años.RESULTADOS:En comparación con los pacientes que recibieron quimioterapia sola, aquellos que además fueron sometidos a radioterapia adicional presentaron un margen significativo de menor tasa de recurrencia pélvica lateral (6.6% vs. 13.0%; p=0.051). En el grupo de pacientes con ganglios linfáticos laterales positivos, los enfermos presentaron una tasa de recurrencia pélvica lateral de 22.6% y 45.1% después de quimioradiaterapia neoadyuvante en comparación con quimioterapia sola respectivamente. Cabe mencionar que el 34.9% de los pacientes con ganglios linfáticos laterales positivos antes del tratamiento persistieron después de la quimioradioterapia neoadyuvante, reportándose finalmente una recurrencia pélvica lateral de un 63.3%.LIMITACIONES:Se trata de un análisis posthoc y solo los pacientes del hospital fueron incluidos, lo que limita el tamaño de la muestra. Además, no se efectuó la disección de los ganglios linfáticos laterales en este grupo.CONCLUSIONES:La radioterapia en los esquemas de neoadyuvancia no logran controlar la recurrencia pélvica lateral en forma adecuada. Algunos subgrupos de pacientes podría requerir de disección adicional. Consulte Video Resumen en http://links.lww.com/DCR/B613.

Targeting Feedforward Loops Formed by Nuclear Receptor RORγ and Kinase PBK in mCRPC with Hyperactive AR Signaling.

Metastatic castration-resistant prostate cancer (mCRPC) is a highly aggressive disease with few therapeutic options. Hyperactive androgen receptor (AR) signaling plays a key role in CRPC progression. Previously, we identified RAR-related orphan receptor gamma (RORγ) as a novel key driver of AR gene overexpression and increased AR signaling. We report here that several RORγ antagonists/inverse agonists including XY018 and compound 31 were orally effective in potent inhibition of the growth of tumor models including patient-derived xenograft (PDX) tumors. RORγ controls the expression of multiple aggressive-tumor gene programs including those of epithelial-mesenchymal transition (EMT) and invasion. We found that PDZ binding kinase (PBK), a serine/threonine kinase, is a downstream target of RORγ that exerts the cellular effects. Alterations of RORγ expression or function significantly downregulated the mRNA and protein level of PBK. Our further analyses demonstrated that elevated PBK associates with and stabilizes RORγ and AR proteins, thus constituting novel, interlocked feed-forward loops in hyperactive AR and RORγ signaling. Indeed, dual inhibition of RORγ and PBK synergistically inhibited the expression and function of RORγ, AR, and AR-V7, and the growth and survival of CRPC cells. Therefore, our study provided a promising, new strategy for treatment of advanced forms of prostate cancer.

Genome-wide analysis identifies critical DNA methylations within NTRKs genes in colorectal cancer.

BACKGROUND: Neurotrophic tropomyosin receptor kinases (NTRKs) are a gene family function as oncogene or tumor suppressor gene in distinct cancers. We aimed to investigate the methylation and expression profiles and prognostic value of NTRKs gene in colorectal cancer (CRC). METHODS: An analysis of DNA methylation and expression profiles in CRC patients was performed to explore the critical methylations within NTRKs genes. The methylation marker was validated in a retrospectively collected cohort of 229 CRC patients and tested in other tumor types from TCGA. DNA methylation status was determined by quantitative methylation-specific PCR (QMSP). RESULTS: The profiles in six CRC cohorts showed that NTRKs gene promoter was more frequently methylated in CRC compared to normal mucosa, which was associated with suppressed gene expression. We identified a specific methylated region within NTRK3 promoter targeted by cg27034819 and cg11525479 that best predicted survival outcome in CRC. NTRK3 promoter methylation showed independently predictive value for survival outcome in the validation cohort (P = 0.004, HR 2.688, 95% CI [1.355, 5.333]). Based on this, a nomogram predicting survival outcome was developed with a C-index of 0.705. Furthermore, the addition of NTRK3 promoter methylation improved the performance of currently-used prognostic model (AIC: 516.49 vs 513.91; LR: 39.06 vs 43.64, P = 0.032). Finally, NTRK3 promoter methylation also predicted survival in other tumors, including pancreatic cancer, glioblastoma and stomach adenocarcinoma. CONCLUSIONS: This study highlights the essential value of NTRK3 methylation in prognostic evaluation and the potential to improve current prognostic models in CRC and other tumors.

Nomograms for Prediction of Molecular Phenotypes in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) patients with different molecular phenotypes, including microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and somatic mutations in BRAF and KRAS gene, vary in treatment response and prognosis. However, molecular phenotyping under adequate quality control in a community-based setting may be difficult. We aimed to build the nomograms based on easily accessible clinicopathological characteristics to predict molecular phenotypes. METHODS: Three hundred and six patients with pathologically confirmed stage I-IV CRC were included in the cohort. The assays for MSI, CIMP, and mutations in BRAF and KRAS gene were performed using resected tumor samples. The candidate predictors were identified from clinicopathological variables using multivariate Logistic regression analyses to construct the nomograms that could predict each molecular phenotype. RESULTS: The incidences of MSI, CIMP, BRAF mutation and KRAS mutation were 25.3% (72/285), 2.5% (7/270), 3.4% (10/293), and 34.8% (96/276) respectively. In the multivariate Logistic analysis, poor differentiation and high neutrophil/lymphocyte ratio (NLR) were independently associated with MSI; poor differentiation, high NLR and high carcinoembryonic antigen/tumor size ratio (CSR) were independently associated with CIMP; poor differentiation, lymphovascular invasion and high CSR were independently associated with BRAF mutation; poor differentiation, proximal tumor, mucinous tumor and high NLR were independently associated with KRAS mutation. Four nomograms for MSI, CIMP, BRAF mutation and KRAS mutation were developed based on these independent predictors, the C-indexes of which were 61.22% (95% CI: 60.28-62.16%), 95.57% (95% CI: 95.20-95.94%), 83.56% (95% CI: 81.54-85.58%), and 69.12% (95% CI: 68.30-69.94%) respectively. CONCLUSION: We established four nomograms using easily accessible variables that could well predict the presence of MSI, CIMP, BRAF mutation and KRAS mutation in CRC patients.

High platelet-to-lymphocyte ratio predicts improved survival outcome for perioperative NSAID use in patients with rectal cancer.

PURPOSE: Nonsteroidal anti-inflammatory drugs (NSAIDs) have been shown to block tumor-associated inflammation in rectal cancer. However, the perioperative use of NSAIDs remains controversial. This study was designed to investigate whether the perioperative use of NSAIDs influences outcomes and to provide a predictive marker to identify patients who would benefit from NSAIDs. METHODS: We enrolled 515 patients with stage I to III rectal cancer in this retrospective study. Patients were classified into the NSAID and non-NSAID groups according to their perioperative use of NSAIDs. The whole cohort was stratified by platelet-to-lymphocyte ratio (PLR). The primary endpoints were disease-free survival (DFS) and overall survival (OS). RESULTS: The NSAID group had a 12.6% lower risk of recurrence than the non-NSAID group (P = 0.015), while the association with survival was nonsignificant. In the high-PLR subset, the NSAID group had a 17.3% lower risk of recurrence (P = 0.003) and a better DFS (P = 0.033) outcome than the non-NSAID group. Multivariate analysis confirmed this independent significant association with DFS (P = 0.023). In the low-PLR subset, the association of NSAID use with survival was nonsignificant. CONCLUSION: Perioperative use of NSAIDs was associated with improved survival outcomes in rectal cancer patients with high PLR.

Therapeutic Targeting of MDR1 Expression by RORγ Antagonists Resensitizes Cross-Resistant CRPC to Taxane via Coordinated Induction of Cell Death Programs.

Overexpression of ATP-binding cassette subfamily B member 1 (ABCB1)-encoded multidrug resistance protein 1 (MDR1) constitutes a major mechanism of cancer drug resistance including docetaxel (DTX) and cabazitaxel (CTX) resistance in castration-resistant prostate cancer (CRPC). However, no therapeutics that targets MDR1 is available at clinic for taxane sensitization. We report here that retinoic acid receptor-related orphan receptor γ (RORγ), a nuclear receptor family member, unexpectedly mediates MDR1/ABCB1 overexpression. RORγ plays an important role in controlling the functions of subsets of immune cells and has been an attractive target for autoimmune diseases. We found that its small-molecule antagonists are efficacious in resensitizing DTX and CTX cross-resistant CRPC cells and tumors to taxanes in both androgen receptor-positive and -negative models. Our mechanistic analyses revealed that combined treatment with RORγ antagonists and taxane elicited a robust synergy in killing the resistant cells, which involves a coordinated alteration of p53, Myc, and E2F-controlled programs critical for both intrinsic and extrinsic apoptosis, survival, and cell growth. Our results suggest that targeting RORγ with small-molecule inhibitors is a novel strategy for chemotherapy resensitization in tumors with MDR1 overexpression.

RORγ is a targetable master regulator of cholesterol biosynthesis in a cancer subtype.

Tumor subtype-specific metabolic reprogrammers could serve as targets of therapeutic intervention. Here we show that triple-negative breast cancer (TNBC) exhibits a hyper-activated cholesterol-biosynthesis program that is strongly linked to nuclear receptor RORγ, compared to estrogen receptor-positive breast cancer. Genetic and pharmacological inhibition of RORγ reduces tumor cholesterol content and synthesis rate while preserving host cholesterol homeostasis. We demonstrate that RORγ functions as an essential activator of the entire cholesterol-biosynthesis program, dominating SREBP2 via its binding to cholesterol-biosynthesis genes and its facilitation of the recruitment of SREBP2. RORγ inhibition disrupts its association with SREBP2 and reduces chromatin acetylation at cholesterol-biosynthesis gene loci. RORγ antagonists cause tumor regression in patient-derived xenografts and immune-intact models. Their combination with cholesterol-lowering statins elicits superior anti-tumor synergy selectively in TNBC. Together, our study uncovers a master regulator of the cholesterol-biosynthesis program and an attractive target for TNBC.

Prognostic value of preoperative carcinoembryonic antigen/tumor size in rectal cancer.

BACKGROUND: Carcinoembryonic antigen (CEA) is a commonly used biomarker in colorectal cancer. However, controversy exists regarding the insufficient prognostic value of preoperative serum CEA alone in rectal cancer. Here, we combined preoperative serum CEA and the maximum tumor diameter to correct the CEA level, which may better reflect the malignancy of rectal cancer. AIM: To assess the prognostic impact of preoperative CEA/tumor size in rectal cancer. METHODS: We retrospectively reviewed 696 stage I to III rectal cancer patients who underwent curative tumor resection from 2007 to 2012. These patients were randomly divided into two cohorts for cross-validation: training cohort and validation cohort. The training cohort was used to generate an optimal cutoff point and the validation cohort was used to further validate the model. Maximally selected rank statistics were used to identify the optimum cutoff for CEA/tumor size. The Kaplan-Meier method and log-rank test were used to plot the survival curve and to compare the survival data. Univariate and multivariate Cox regression analyses were used to determine the prognostic value of CEA/tumor size. The primary and secondary outcomes were overall survival (OS) and disease-free survival (DFS), respectively. RESULTS: In all, 556 patients who satisfied both the inclusion and exclusion criteria were included and randomly divided into the training cohort (2/3 of 556, n = 371) and the validation cohort (1/3 of 556, n = 185). The cutoff was 2.429 ng/mL per cm. Comparison of the baseline data showed that high CEA/tumor size was correlated with older age, high TNM stage, the presence of perineural invasion, high CEA, and high carbohydrate antigen 19-9 (CA 19-9). Kaplan-Meier curves showed a manifest reduction in 5-year OS (training cohort: 56.7% vs 81.1%, P < 0.001; validation cohort: 58.8% vs 85.6%, P < 0.001) and DFS (training cohort: 52.5% vs 71.9%, P = 0.02; validation cohort: 50.3% vs 79.3%, P = 0.002) in the high CEA/tumor size group compared with the low CEA/tumor size group. Univariate and multivariate analyses identified CEA/tumor size as an independent prognostic factor for OS (training cohort: hazard ratio (HR) = 2.18, 95% confidence interval (CI): 1.28-3.73, P = 0.004; validation cohort: HR = 4.83, 95%CI: 2.21-10.52, P < 0.001) as well as DFS (training cohort: HR = 1.47, 95%CI: 0.93-2.33, P = 0.096; validation cohort: HR = 2.61, 95%CI: 1.38-4.95, P = 0.003). CONCLUSION: Preoperative CEA/tumor size is an independent prognostic factor for patients with stage I-III rectal cancer. Higher CEA/tumor size is associated with worse OS and DFS.

Discovery and Characterization of XY101, a Potent, Selective, and Orally Bioavailable RORγ Inverse Agonist for Treatment of Castration-Resistant Prostate Cancer.

We report the design, optimization, and biological evaluation of nuclear receptor RORγ inverse agonists as therapeutic agents for prostate cancer treatment. The most potent compound 27 (designated as XY101) exhibited cellular activity with an IC50 value of 30 nM in a cell-based reporter gene assay with good selectivity against other nuclear receptor subtypes. The cocrystal structure of 27 in complex with the RORγ ligand binding domain provided a solid structural basis for its antagonistic mechanism. 27 potently inhibited cell growth, colony formation, and the expression of AR, AR-V7, and PSA. 27 also exhibited good metabolic stability and a pharmacokinetic profile with oral bioavailability of 59% and a half-life of 7.3 h. Notably, 27 demonstrated promising therapeutic effects with significant tumor growth inhibition in a prostate cancer xenograft model in mice. The potent, selective, metabolically stable, and orally available RORγ inverse agonists represent a new class of compounds as potential therapeutics against prostate cancer.

The Effects of Sleeve Gastrectomy on Glucose Metabolism and Glucagon-Like Peptide 1 in Goto-Kakizaki Rats.

PURPOSE: To investigate the effects of sleeve gastrectomy (SG) on glucose metabolism and changes in glucagon-like peptide 1 (GLP-1) in Goto-Kakizaki (GK) rats. METHODS: GK rats were randomly assigned to one of three groups: SG, SG pair-fed plus sham surgery (PF-sham), and ad libitum-fed no surgery (control). Food intake, body weight, blood glucose, GLP-1 and insulin levels, and GLP-1 expression in the jejunum and ileum were compared. RESULTS: The SG rats exhibited lower postoperative food intake, body weight, and fasting glucose than did the control rats (P < 0.05). SG significantly improved glucose and insulin tolerance (P < 0.05). Plasma GLP-1 levels were higher in SG rats than in control or PF-sham rats in the oral glucose tolerance test (OGTT) (P < 0.05). Blood glucose levels expressed as a percentage of baseline were higher in SG rats than in control rats after exendin (9-39) administration (P < 0.05). The levels of GLP-1 expression in the jejunum and ileum were higher in SG rats than in PF-sham and control rats (P < 0.05). CONCLUSIONS: Improvement of glucose metabolism by SG was associated with increased GLP-1 secretion. SG contributes to an increase in plasma GLP-1 levels via increased GLP-1 expression in the mucosa of the jejunum and/or ileum.

Epigenetic silencing of TPM2 contributes to colorectal cancer progression upon RhoA activation.

Beta-tropomyosin (ß-tropomyosin, TPM2) has been found to be downregulated in colorectal cancer (CRC) in previous studies. In this study, we aimed to investigate the mechanisms and potential biological consequences of the downregulation of TPM2 in colorectal cancer. TPM2 expression in colorectal cancer was assessed by qRT-PCR and immunostaining. The biological functions of TPM2 were assessed in cell lines either overexpressing or underexpressingTPM2. Aberrant DNA methylation in the promoter region is associated with suppression of TPM2 expression in primary colorectal cancer tissue samples. Treatment with the demethylation agent 5-AZA can induceTPM2 expression in colorectal cancer cell lines. Reconstitution of TPM2 suppresses cell proliferation and migration in colorectal cancer cell lines, whereas the loss of TPM2 expression is associated with increased tumor proliferation and migration in vitro, which was accompanied by RhoA activation. In summary, our findings indicate that TPM2 appears to be commonly silenced by aberrant DNA methylation in colon cancer. TPM2 loss is associated with RhoA activation and tumor proliferation.

[Construction and identification of the human liver-specific miR-122 expression vector].

miR-122 is the most abundant miRNA in adult human liver. To study the functions of miR-122 in liver disease, we amplified the precursor of human miR-122 gene by polymerase chain reaction (PCR) from the HepG2 genomic DNA, and then constructed miR-122 expression vector pLMP-miR-122. pLMP-miR-122 could overexpress mature miR-122 when human normal liver cells L-O2 and the hepatoma cells HepG2 were transfected with it. When HepG2 cells were co-transfected with HBV1.3 and pLMP-miR-122, we found that miR-122 could down-regulate the expression of HBs and HBe antigen. These results showed that the human liver specific miR-122 expression vector was constructed successfully, and it could regulate the replication and the expression of HBV genes. The plasmid pLMP-miR-122 will facilitate further studies of the functions of miR-122 in the development of liver virus infection diseases and HCC.

A retrovirus-based system to stably silence GDF-8 expression and enhance myogenic differentiation in human rhabdomyosarcoma cells.

BACKGROUND: Myostatin, also called GDF-8, a secreted growth and differentiating factor that belongs to the transforming growth factor-beta superfamily, is a known negative regulator of myogenesis in vivo. Overexpression of GDF-8 contributes to the lack of differentiation in human rhabdomyosarcoma (RMS) cells. We investigated whether a retrovirus-based RNA interference (RNAi) system against GDF-8 expression in human RMS cells would enhance myogenic differentiation. METHODS: A retrovirus-based RNAi system was developed that utilized the U6-RNA polymerase III promoter to drive efficient expression and deliver the GDF8-specific short hairpin RNAs (shRNAs) in human RMS cell A204. In this system, the retrovirus vector was integrated into the host cell genome and allowed stable expression of shRNAs. GDF-8 expression was determined by real-time polymerase chain reaction and western blotting analysis. An 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed to determine the cell proliferation. Myogenic differentiation markers were monitored by western blotting analysis. Cell cycle and apoptosis was determined by propidium iodide staining and analysed in a flow cytometer. RESULTS: In the siGDF8 A204 cell pools, the levels of both GDF-8 mRNA and protein were dramatically reduced by this RNAi system. In differentiation conditions, inhibition of myostatin synthesis led to enhanced cell cycle withdrawal, consequently stimulated myogenic differentiation and increased the rate of tumor cell apoptosis. CONCLUSIONS: The results demonstrate that deactivation of myostatin by using retrovirus-based RNAi thus may be useful for therapy in rhabdomyosarcomas.