H3K36 methyltransferase SMYD2 affects cell proliferation and migration in Hirschsprung's disease by regulating METTL3.

The pathogenesis of Hirschsprung's disease (HSCR) is complex. Recently, it has been found that histone modifications can alter genetic susceptibility and play important roles in the proliferation, differentiation and migration of neural crest cells. H3K36 methylation plays a significant role in gene transcriptional activation and expression, but its pathogenic mechanism in HSCR has not yet been studied. This study aimed to elucidate its role and molecular mechanism in HSCR. Western blot analysis, immunohistochemistry (IHC) and reverse transcription-quantitative PCR (RT‒qPCR) were used to investigate H3K36 methylation and methyltransferase levels in dilated and stenotic colon tissue sections from children with. We confirm that SMYD2 is the primary cause of differential H3K36 methylation and influences cell proliferation and migration in HSCR. Subsequently, quantitative detection of m6A RNA methylation revealed that SMYD2 can alter m6A methylation levels. Western blot analysis, RT-qPCR, co-immunoprecipitation (co-IP), and immunofluorescence colocalization were utilized to confirm that SMYD2 can regulate METTL3 expression and affect m6A methylation, affecting cell proliferation and migration. These results confirm that the H3K36 methyltransferase SMYD2 can affect cell proliferation and migration in Hirschsprung's disease by regulating METTL3. Our study suggested that H3K36 methylation plays an important role in HSCR, confirming that the methyltransferase SMYD2 can affect m6A methylation levels and intestinal nervous system development by regulating METTL3 expression.

Facial recognition models for identifying genetic syndromes associated with pulmonary stenosis in children.

BACKGROUND: Williams-Beuren syndrome, Noonan syndrome, and Alagille syndrome are common types of genetic syndromes (GSs) characterized by distinct facial features, pulmonary stenosis, and delayed growth. In clinical practice, differentiating these three GSs remains a challenge. Facial gestalts serve as a diagnostic tool for recognizing Williams-Beuren syndrome, Noonan syndrome, and Alagille syndrome. Pretrained foundation models (PFMs) can be considered the foundation for small-scale tasks. By pretraining with a foundation model, we propose facial recognition models for identifying these syndromes. METHODS: A total of 3297 (n = 1666) facial photos were obtained from children diagnosed with Williams-Beuren syndrome (n = 174), Noonan syndrome (n = 235), and Alagille syndrome (n = 51), and from children without GSs (n = 1206). The photos were randomly divided into five subsets, with each syndrome and non-GS equally and randomly distributed in each subset. The proportion of the training set and the test set was 4:1. The ResNet-100 architecture was employed as the backbone model. By pretraining with a foundation model, we constructed two face recognition models: one utilizing the ArcFace loss function, and the other employing the CosFace loss function. Additionally, we developed two models using the same architecture and loss function but without pretraining. The accuracy, precision, recall, and F1 score of each model were evaluated. Finally, we compared the performance of the facial recognition models to that of five pediatricians. RESULTS: Among the four models, ResNet-100 with a PFM and CosFace loss function achieved the best accuracy (84.8%). Of the same loss function, the performance of the PFMs significantly improved (from 78.5% to 84.5% for the ArcFace loss function, and from 79.8% to 84.8% for the CosFace loss function). With and without the PFM, the performance of the CosFace loss function models was similar to that of the ArcFace loss function models (79.8% vs 78.5% without PFM; 84.8% vs 84.5% with PFM). Among the five pediatricians, the highest accuracy (0.700) was achieved by the senior-most pediatrician with genetics training. The accuracy and F1 scores of the pediatricians were generally lower than those of the models. CONCLUSIONS: A facial recognition-based model has the potential to improve the identification of three common GSs with pulmonary stenosis. PFMs might be valuable for building screening models for facial recognition. Key messages What is already known on this topic:  Early identification of genetic syndromes (GSs) is crucial for the management and prognosis of children with pulmonary stenosis (PS). Facial phenotyping with convolutional neural networks (CNNs) often requires large-scale training data, limiting its usefulness for GSs. What this study adds:  We successfully built multi-classification models based on face recognition using a CNN to accurately identify three common PS-associated GSs. ResNet-100 with a pretrained foundation model (PFM) and CosFace loss function achieved the best accuracy (84.8%). Pretrained with the foundation model, the performance of the models significantly improved, although the impact of the type of loss function appeared to be minimal. How this study might affect research, practice, or policy:  A facial recognition-based model has the potential to improve the identification of GSs in children with PS. The PFM might be valuable for building identification models for facial detection.

Effects of White Noise on Pain Scores and Salivary Cortisol Levels in Surgical Neonates: A Randomized Controlled Trial.

BACKGROUND: Neonates experience varying intensities of pain after surgery. While white noise has been used for postoperative pain relief in infants, its effects on neonates after surgery need further exploration. PURPOSE: This study aimed to evaluate the effects of white noise on pain scores and salivary cortisol levels in surgical neonates. METHODS: In this randomized controlled trial, 64 neonates scheduled for surgery were recruited and assigned by block randomization into 2 groups. The intervention group listened to white noise at 50 dB, while the control group listened to white noise at 0 dB, for 30 minutes 6 times for 48 hours postoperatively. Pain scores, measured by the COMFORTneo Scale, and salivary cortisol levels were compared. RESULTS: Although pain scores decreased after surgery in all subjects, no statistically significant difference was observed between the 2 groups (P = .937). There was a significant difference between pre- and postintervention pain scores in the intervention group only (P = .006). Salivary cortisol levels decreased after intervention in the intervention group, but there was no significant difference between pre- and postintervention levels in the 2 groups (P = .716). IMPLICATIONS FOR PRACTICE: Given the reduction in pain scores and salivary cortisol concentrations after white noise intervention, white noise shows potential as an adjunctive soothing measure for neonates after surgery. IMPLICATIONS FOR RESEARCH: Future studies are needed to confirm the efficacy and utility of white noise intervention in clinical settings.

Case report and literature review: Asymptomatic littoral cell angioma in a 3-year-old girl.

Background: Littoral cell angioma (LCA) is an extremely uncommon benign vascular tumor of the spleen. Cases of LCA in infants are rarely reported, and due to the rarity of the tumor and non-specific symptoms, the diagnosis of LCA is often overlooked in clinical practice. Case report: We present a 3-year-old girl with pulmonary inflammation who was admitted to the hospital due to the discovery of a space-occupying lesion in the spleen. Pathology after splenectomy confirmed LCA, and there was no recurrence observed at the 5-month follow-up examination. Conclusion: LCA should be considered when a child shows asymptomatic splenomegaly, with antigen expression indicating dual positivity of endothelial and histiocytic markers. Laparoscopic splenectomy remains the primary method of treating LCA.

Hirschsprung's disease: m6A methylase VIRMA suppresses cell migration and proliferation by regulating GSK3ß.

BACKGROUND: N6-methyladenosine (m6A) is the most abundant mRNA modification in mammals, participating in various biological processes. VIRMA is a key methyltransferase involved in m6A modification. However, the role of VIRMA in Hirschsprung's disease (HSCR) remains unclear. This study aims to investigate the function of VIRMA in HSCR and identify its corresponding regulatory mechanisms. METHODS: The expression of VIRMA and GSK3ß in colon tissues of HSCR was examined using RT-qPCR, Western blot, and Immunohistochemistry. Immunofluorescence detected localization of VIRMA and GSK3ß. Cell proliferation was measured by CCK8 and EdU assays, and cell migration was evaluated via cell migration and wound healing assays. The stability of GSK3ß mRNA was assessed using the actinomycin D assay and the overall level of m6A in cells was assessed by colorimetric assay. RESULTS: VIRMA was significantly downregulated in narrow-segment colon tissue. Silencing of VIRMA inhibited cell proliferation and migration. VIRMA can inhibit the degradation of GSK3ß mRNA and increase the expression of GSK3ß. GSK3ß was significantly upregulated in narrow-segment colon tissues. Accordingly, our findings showed that GSK3ß mediated the VIRMA-driven cell migration and proliferation. CONCLUSION: VIRMA can inhibit cell migration and proliferation by upregulating the expression of GSK3ß, contributing to the onset of HSCR. IMPACT: The expressions of VIRMA were significantly reduced in HSCR, while GSK3ß expression was increased in HSCR, and can be used as a molecular marker. VIRMA overexpression promoted the proliferation and migration of SH-SY5Y and HEK-293T cells. VIRMA can inhibit the degradation of GSK3ß mRNA and increase the expression of GSK3ß.

Surgical prediction of neonatal necrotizing enterocolitis based on radiomics and clinical information.

PURPOSE: To assess the predictive value of radiomics for surgical decision-making in neonatal necrotizing enterocolitis (NEC) when abdominal radiographs (ARs) do not suggest an absolute surgical indication for free pneumoperitoneum. METHODS: In this retrospective study, we finally included 171 newborns with NEC and obtained their ARs and clinical data. The dataset was randomly divided into a training set (70%) and a test set (30%). We developed machine learning models for predicting surgical treatment using clinical features and radiomic features, respectively, and combined these features to build joint models. We assessed predictive performance of the different models by receiver operating characteristic curve (ROC) analysis and compared area under curve (AUC) using the Delong test. Decision curve analysis (DCA) was used to assess the potential clinical benefit of the models to patients. RESULTS: There was no significant difference in AUC between the clinical model and the four radiomic models (P > 0.05). The XGBoost joint model had better predictive efficacy and stability (AUC, training set: 0.988, test set: 0.959). Its AUC in the test set was significantly higher than that of the clinical model (P < 0.05). DCA showed that the XGBoost joint model achieved higher net clinical benefit compared to the clinical model in the threshold probability range (0.2-0.6). CONCLUSION: Radiomic features based on AR are objective and reproducible. The joint model combining radiomic features and clinical signs has good surgical predictive efficacy and may be an important method to help primary neonatal surgeons assess the surgical risk of NEC neonates.

Pneumonia, lymphocytes and C-reactive protein are valuable tests for predicting surgical intervention in necrotizing enterocolitis.

Background: Necrotizing enterocolitis (NEC) is one of the important causes of neonatal death, and proper timing of operation is of critical significance. This study aimed to explore the high-risk factors for NEC requiring surgical intervention and to provide a reference for its clinical diagnosis and treatment. Methods: Clinical and radiological evidence of NEC neonates admitted to Zhujiang Hospital of Southern Medical University and Zhongshan Boai Hospital from January 2010 to October 2022 were retrospectively analyzed. Patients were divided into surgical group and conservative group according to whether they underwent surgery or not. Univariate analysis of the clinical data of the two groups was conducted, and multivariate logistic regression analysis was then performed for statistically significant results in the univariate analysis. Results: 267 infants were included in this study, of which 90 patients underwent surgical intervention for NEC and 177 conservation treatment. The univariate analysis showed that the gestational age, pneumonia, leukocytes, lymphocytes, erythrocytes, platelets, C-reactive protein, and blood glucose were statistically significant in the surgical group compared to the conservative group (All P < 0.05). Furthermore, the results of multivariate logistic regression analysis showed that compared to the conservative group, patients in the surgical group had a higher proportion of pneumonia (OR = 2.098; 95% CI: 1.030-4.272; P = 0.041), lower lymphocyte values (OR = 0.749; 95% CI: 0.588-0.954; P = 0.019), and higher C-reactive protein values (OR = 1.009; 95% CI: 1.003-1.016; P = 0.004). Conclusions: Pneumonia, decreased lymphocytes, and elevated C-reactive protein are potential high-risk factors for neonates with NEC requiring surgical intervention and may have potential clinical implications for predicting surgical risk.

Case report: A case of epidermolysis bullosa complicated with pyloric atresia and a literature review.

Objective: This article aims to explore the diagnosis, molecular characteristics, treatment, and prognosis of epidermolysis bullosa with pyloric atresia (EB-PA). Methods: The clinical manifestations, diagnosis and treatment, and genetic characteristics of a patient with EB-PA admitted to our hospital were analysed. The disease subtypes, concomitant abnormalities, molecular characteristics, and prognosis of patients with EB-PA were summarized by searching the EB-PA-related literature since 2011. Results: We present a very low birth weight female infant with skin blisters and pyloric obstruction. Exome sequencing revealed heterozygous mutations in the ITGB4 gene: c.794dupC (p. S265fs*5) and c.2962G > A (p.A988T). This infant was diagnosed with EB-PA. Coverage of the wounds and Penicillin were used to prevent infection, but the patient eventually developed severe sepsis. A literature review was carried out including 49 cases of EB-PA; among these cases, 34 were preterm infants, weighing between 930 and 3,640 g. Of these EB-PA patients, 28 had accompanying malformations, including urinary system malformations and aplasia cutis congenita (ACC). Thirty-two patients identified the subtype of EB-PA, of whom 25 were diagnosed with junctional epidermolysis bullosa (JEB), 6 with epidermolysis bullosa simplex (EBS), and 1 with dystrophic epidermolysis bullosa (DEB). Genetic testing was conducted on 23 patients, of whom 15 carried Integrin Beta-4 (ITGB4) gene mutations and one JEB patient carried an Integrin Alpha-6 (ITGA6) gene mutation; 4 of the 5 EBS patients had Plectin (PLEC) gene mutations, and the other had an ITGB4 mutation. ITGB4 mutation cases involved 29 mutation sites, primarily concentrated in the region encoding the integrin beta subunit; PLEC mutation cases involved 7 mutation sites. Among all cases, 43 underwent pyloric atresia surgery, of whom 24 died postoperatively, and 6 without surgery therapy died within a short period. Conclusion: EB-PA is a rare genetic disorder characterized by increased skin fragility and PA involving mutations in the ITGB4, PLEC, or ITGA6 genes. EB-PA has a high incidence of complications and mortality, surgery and supportive therapy are currently the most common treatment options.

Caudal duplication syndrome: 10-year experiences with a comprehensive literature review.

PURPOSE: Caudal duplication syndrome (CDS) has rarely been reported. The purpose was to describe the characteristics and discuss possible pathogenesis of CDS by reviewing our experience along with a comprehensive literature review. METHODS: A total of 51 patients including 3 from our team and 48 from literature were selected in this study. General condition, clinical manifestations, type of anomalies, treatment and prognosis was analyzed and summarized. RESULTS: Among the 51 patients were 30 females and 21 males, and age at first clinical visit was from birth to 39 years old. Except 12 patients, most of the patients had no troubling clinical manifestation. Physical examination showed that 30 patients had 1 perineum, 21 patients had 2 completely independent perineums. Degree of duplication varied; colon-rectum tubular, bladders and urethras, vaginas in females and penis shafts and glans in males were found to be the most common type of alimentary system and urogenital system duplication in this study with 24/51, 41/51, 10/30 and 16/21 patients, respectively. Anorectal malformation was calculated: 18 had 2 ARMs, 14 had 1 normal anus and 1 ARM on the other side, 12 had a normal anus, 5 had 2 normal anus, the remaining 2 patients had only 1 ARM. Spinal cord anomalies were showed as meningomyeloceles and lipomas in 13 and 3 patients. Vertebral anomalies of bifid, dysplasias, scoliosis, and hemivertebra were noticed in 28 patients and accessory dysplasia lower limbs were found in 10 patients. Prognosis showed 39 of the 51 patients had normal function in urination and defecation. CONCLUSIONS: CDS is an extremely rare disease with uncertain pathogenesis. Colon-rectum tubular duplication with two ARMs, duplicated bladders and urethras, double vaginas in females and penis shafts and glans in males are the most common type. Long-term prognosis is good with multidisciplinary, individualized and staged surgical procedures.

Early enteral feeding versus traditional feeding in neonatal congenital gastrointestinal malformation undergoing intestinal anastomosis: A randomized multicenter controlled trial of an enhanced recovery after surgery (ERAS) component.

PURPOSE: the aim of this clinical trial was to evaluate the safety and efficacy of early enteral feeding (EEN) following intestinal anastomosis in neonates with congenital gastrointestinal malformation. METHODS: a multicenter, prospective, randomized controlled trial (registered under chictr.org.cn Identifier no.ChiCTR-INR-17014179) was conducted between 2018 and 2019. Four centers in China analyzed 156 newborns of congenital gastrointestinal malformation undergoing intestinal anastomosis to EEN group (n = 78) or control (C) group (n = 78). The primary outcomes of this study were length of postoperative stay (LOPS) and time to full feeds. Secondary outcomes included morbidity of complications, parenteral nutrition (PN) duration, feeding intolerance, 30 day mortality rate and 30 day readmission rate. RESULTS: the mean time to full feeds and LOPS in the EEN group were 15.0 (9.8-22.8) days and 17.6 (12.0-29.8) days, while that were 18.0 (12.0-24.0) days and 20.0 (15.0-30.3) days in C groups respectively. There was no significant difference between two groups(P >0.05). No significant intergroup difference was found with respect to postoperative morbidity, PN duration or feeding intolerance(P >0.05). CONCLUSIONS: early enteral feeding following intestinal anastomosis in neonates with congenital gastrointestinal malformation is safe. Post-operative outcomes demonstrated a trend toward improvement. LEVEL OF EVIDENCE: Level Ⅰ.

miR-483-3p promotes proliferation and migration of neuroblastoma cells by targeting PUMA.

Neuroblastoma is the most common extra-cranial solid tumor in infants and children and accounts for about 15% of deaths from childhood cancers. MicroRNAs (miRNAs) have been shown to play an important role in several cellular processes, such as cell proliferation, apoptosis, invasion, metastasis and angiogenesis, and therefore have been implicated in cancer progression. miR-483-3p is associated with neuroblastoma and is found to function as an 'onco-miR' in some malignancies. However, its role in neuroblastoma remains poorly understood. In this study, we confirmed that miR-483-3p is overexpressed in neuroblastoma tissue when compared with normal tissue and miR-483-3p expression is also associated with tumor stage. Overexpression of miR-483-3p substantially enhanced cell proliferation, migration, and invasion of neuroblastoma cells. miR-483-3p also promoted tumor growth of neuroblastoma in vivo. Both in vivo and in vitro experiments showed that the tumor suppressor PUMA was a target of miR-483-3p. Furthermore, down-regulation of PUMA by small interfering RNA (siRNA) exhibited similar effects to those observed as a result of overexpression of miR-483-3p. Our results indicate that miR-483-3p could function as an 'onco-miR' in human neuroblastoma and reveal a new and potentially important target for neuroblastoma anticancer therapy.

A double suicide gene system driven by vascular endothelial growth factor promoter selectively kills human hepatocellular carcinoma cells.

The aim of the present study was to investigate the selective killing effect on hepatocellular carcinoma (HCC) cells of an adenovirus (Ad)-mediated cytosine deaminase (CD) in combination with thymidine kinase (TK) suicide gene system, driven by the vascular endothelial growth factor promoter (VEGFp), in vitro and in vivo. A double suicide gene system with VEGFp, named Ad-VEGFp-CDglyTK, was constructed and transfected into human HCC cells (BEL-7402 or HepG2; the latter cell type is deficient in VEGF) and human umbilical vein vascular endothelial cells (HUVEC). Green fluorescent protein expression was detected by fluoroscopy to verify transfection efficiency, and CDglyTK gene expression was detected by reverse transcription-polymerase chain reaction (PCR). The selective killing effect of Ad-VEGFp-CDglyTK was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and flow cytometry (FCM) in vitro and by xenograft studies in vivo. PCR revealed that the transgenic CDglyTK gene was expressed in BEL-7402 cells and HUVEC, but not in HepG2 cells. The cell survival rate significantly decreased in line with increasing concentrations of the prodrugs, ganciclovir (GCV) alone, 5-fluorocytosine (5-FC) alone or a combination of the two, in HUVEC and BEL-7402 cells with the transfected CDglyTK gene, but not in untransfected HUVEC or BEL-7402 cells, or in transfected or untransfected HepG2 cells. This result was additionally confirmed by FCM. GCV and 5-FC inhibited the HUVEC and BEL-7402 cells containing the transfected CDglyTK gene and also inhibited adjacent unmodified cells via the 'bystander effect'. No similar results were observed in HepG2 cells. Compared with the control group, tumors with the transfected CDglyTK gene were smaller and the microvessel density of the tumor tissue was significantly decreased. It was concluded that a combination TK/GCV and CD/5-FC suicide gene system driven by VEGFp may provide a promising treatment strategy for HCC.

All-trans retinoic acid enhances bystander effect of suicide gene therapy in the treatment of breast cancer.

All-trans retinoic acid (ATRA) has been shown to enhance the expression of connexin 43 (Cx43) and the bystander effect (BSE) in suicide gene therapy. These in turn improve effects of suicide gene therapies for several tumor types. However, whether ATRA can improve BSE remains unclear in suicide gene therapy for breast cancer. In the present study, MCF-7, human breast cancer cells were treated with ATRA in combination with a VEGFP-TK/CD gene suicide system developed by our group. We found that this combination enhances the efficiency of cell killing and apoptosis of breast cancer by strengthening the BSE in vitro. ATRA also promotes gap junction intercellular communication (GJIC) in MCF-7 cells by upregulation of the connexin 43 mRNA and protein in MCF-7 cells. These results indicate that enhancement of GJIC by ATRA in suicide gene system might serve as an attractive and cost-effective strategy of therapy for breast cancer cells.

miR-362-5p inhibits proliferation and migration of neuroblastoma cells by targeting phosphatidylinositol 3-kinase-C2ß.

miR-362-5p is down-regulated in high-risk neuroblastoma and can function as a tumor suppressor. However, its role remains poorly understood. We show that miR-362-5p is down-regulated in metastatic neuroblastoma compared with primary neuroblastoma. Overexpression of miR-362-5p inhibits cell proliferation, migration and invasion of neuroblastoma cells in vitro and suppresses tumor growth of neuroblastoma in vivo. Phosphatidylinositol 3-kinase (PI3K)-C2ß is a target of miR-362-5p. Knockdown of PI3K-C2ß by siRNA had a similar effect to overexpression of miR-362-5p on SH-SY5Y cells. Overexpression of PI3K-C2ß partially reversed tumor-suppressive effects of miR-362-5p. We suggest that miR-362-5p suppresses neuroblastoma cell growth and motility, partially by targeting PI3K-C2ß.

Single-site laparoscopic appendectomy in children using conventional instruments: a prospective, randomized, control trial.

PURPOSE: Single-site laparoscopic surgery (SSLS) is still only used in limited situations to treat children with appendicitis. Using conventional laparoscopic (CL) equipment to perform SSLS appendectomy is considered a valuable application in China. This prospective randomized trial aims to evaluate the surgical outcome of SSLS and CL appendectomy using CL equipment. METHODS: Sixty patients were recruited and randomly assigned to receive SSLS or 3-port CL appendectomy between February 2011 and June 2013. Each case of SSLS appendectomy was performed using CL instruments. Surgery outcomes, including operative time, conversion rates, postoperative complications, hospital stays, and hospital costs were evaluated. RESULTS: Patient characteristics were similar between groups. The SSLS using CL instruments was successful in all the 30 patients and no conversions occurred. Mean operative time was longer in the SSLS group than the CL group (64.3 ± 3.1 vs 53.0 ± 2.9 min, respectively; p = 0.000). Complication rates, lengths of hospital stay, and hospital costs were similar between the two groups. CONCLUSIONS: The findings of this study demonstrate that using conventional instruments to perform SSLS is technically feasible and safe in children. Although SSLS appendectomy does increase the operative time, it does not increase the complication rate and hospital cost.

Effects of an adenoviral vector containing a suicide gene fusion on growth characteristics of breast cancer cells.

The herpes simplex virus thymidine kinase/ganciclovir (HSV­TK/GCV) and the cytosine deaminase/5­fluorocytosine (CD/5­FC) systems have been widely applied in suicide gene therapy for cancer. Although suicide gene therapy has been successfully used in vitro and in vivo studies, the number of studies on the effects of recombinant adenoviruses (Ads) containing suicide genes on target cancer cells is limited. The aim of this study was to examine whether recombinant Ads containing the CD/TK fusion gene affect cell proliferation of breast cancer cells in vitro. In the present study, we explored the use of a recombinant adenoviral vector to deliver the CD/TK fusion gene to the breast cancer cell line MCF­7. We found that the recombinant adenoviral vector efficiently infected MCF­7 cells. Western blot analysis revealed that CD and TK proteins are expressed in the infected cells. The infected breast cancer cells did not show any significant changes in morphology, ultrastructure, cell growth, and cell­cycle distribution compared to the uninfected cells. This study revealed that the Ad­vascular endothelial growth factor promoter (VEGFp)­CD/TK vector is non­toxic to MCF­7 cells at the appropriate titer. Our results indicate that it is feasible to use a recombinant adenoviral vector containing the CD/TK fusion gene in suicide gene therapy to target breast cancer cells.

[A double suicide gene system driven by KDR promoter selectively kills human hepatic carcinoma cells and human umbilical vein endothelial cells].

OBJECTIVE: To study the selective killing effects of adenovirus (Ad)-mediated double suicide gene system driven by KDR promoter (KDR-CdglyTK) on the human hepatic carcinoma cells and human umbilical vein endothelial cells (HUVECs). METHODS: KDR-expressing BEL-7402 and HUVECs and HepG2 cells that did not express KDR were infected by KDR-CdglyTK, and the infection efficiency and the expression of CdglyTK in the cells was detected by RT-PCR. The infected cells were treated with the the prodrugs 5-FC and GCV at different concentrations, and the cell-killing effects and bystander effects were evaluated by MTT method. RESULTS: At the multiplicity of infection (MOI) of 100, the recombinant AdKDR-CDglyTK showed similar infection efficiency in the 3 cell lines. RT-PCR demonstrated CDglyTK expression in the recombinant adenovirus and the 3 infected cell lines. BEL-7402 and HUVECs infected by the KDR-CdglyTK, but not the HepG2 cells, were highly sensitive to the prodrugs (P<0.001). Bystander effects of the double suicide gene system were observed in the coculture of the infected and non-infected BEL-7402 and HUVECs. CONCLUSION: The double suicide gene system driven by KDR promoter has specific killing effect on KDR-expressing hepatocellular carcinoma cells and HUVECs.

[Adenovirus-mediated double suicide gene selectively kills breast cancer MCF-7 cells in vitro].

OBJECTIVE: To evaluate the effect of adenovirus-mediated double suicide gene (CD/TK) for selective killing of breast cancer cells. METHODS: Vascular endothelial growth factor (VEGF)-expressing MCF-7 cells and normal human mammary epithelial cells that did not express VEGF were infected with the adenovirus containing VEGFP-CD/TK-GFP genes. CD/TK gene expression in the infected cells was detected by RT-PCR. After treatment of the infected cells with GCV and/or 5-FC, the cell growth status was evaluated using MTT assay, and the cell cycle changes were detected with flow cytometry. In nude mice bearing human breast cancer, the recombinant adenovirus vector was injected directly into the tumor followed by intraperitoneal injection of the prodrugs GCV and/or 5-FC, and the subsequent tumor growth was observed. RESULTS: The recombinant adenovirus achieved similar infection rates in MCF-7 and human mammary epithelial cells, and the rates increased gradually with the multiplicity of infection (MOI) of the virus. RT-PCR demonstrated the presence of CD/TK gene product in infected MCF-7 cells, but not in the infected mammary epithelial cells. The infected MCF-7 cells, but not the mammary epithelial cells, were highly sensitive to the pro-drugs. The CD/TK fusion gene system showed significantly greater efficiency than either of the single suicide gene in killing the target cells (P<0.01). At the MOI of 100, treatment of the infected cells with the pro-drugs resulted in increased cell percentage in G(0)-G(1) phase and decreased percentage in S phase. In nude mice bearing MCF-7 cell-derived subcutaneous tumor, treatment with the double suicide gene system significantly inhibited the tumor growth, showing much stronger effect than either of the single suicide gene (P<0.01). CONCLUSION: The adenovirus-mediated CD/TK double suicide gene driven by VEGF promoter combined with GCV and 5-FC treatment can be an effective therapy against experimental breast cancer, and produces much greater efficacy than the single suicide gene CD/TK combined with GCV or 5-FC.