Michael L. Megison

Laparoscopic surgery in children with congenital heart disease

PURPOSE The study aim was to determine outcomes of children with congenital heart disease who underwent laparoscopic procedures. METHODS A single-institution, institutional review board-approved, retrospective review was conducted including children younger than 5 years with congenital heart disease who underwent laparoscopic or open abdominal procedures. Patient demographics, operative details, complications, and 30-day mortality were examined. RESULTS Over 10 years, 111 children with congenital heart disease underwent 121 laparoscopic procedures. Median age was 2.5 months, with 87% being infants. Laparoscopic gastrostomy was the most common procedure (101). There was no intraoperative hemodynamic instability, median operative time was 70 minutes, postoperative complications were low (5%), and all children were alive at 30 days. Only 8 patients required conversion from laparoscopic to open, all secondary to technical issues, not hemodynamic instability. There were 42 children with cardiac disease who underwent 45 open procedures during the study period. There were no significant differences between patient demographics, type of procedure, operative time, complications, or 30-day mortality comparing the open and laparoscopic groups. CONCLUSION In this review, there were no major contraindications to performing laparoscopic procedures in children with congenital heart disease, and we conclude that it is reasonably safe to perform laparoscopic surgery on these children.

Feasibility of Single-Incision Pediatric Endosurgery for Treatment of Appendicitis in 415 Children

INTRODUCTION Single-incision pediatric endosurgery (SIPES) has gained popularity for ablative procedures such as appendectomy in many pediatric surgical centers. This study evaluates the outcome of SIPES for treatment of appendicitis in our institution. PATIENTS AND METHODS After Institutional Review Board approval was obtained, data were prospectively collected on all patients undergoing SIPES appendectomy in our hospital from March 2009 through October 2011. The surgical techniques, operative times, complications, conversion rates, and outcomes were recorded. RESULTS SIPES appendectomy was attempted in 415 children (mean age, 10.9 years; age range, 1.4-17.9 years; 266 males, 149 females; median weight, 43 kg; weight range, 9.8-146 kg). Intraoperatively, acute appendicitis was found in 298 cases and perforated appendicitis in 79 cases. Thirty-eight patients underwent interval appendectomy. Appendectomy was carried out solely as SIPES in 397 cases (96%). Median operative time was 40±16 minutes (37±16 minutes for fellows [n=284] and 46±15 minutes for residents [n=131]). There were three intraoperative complications, which could be handled during the procedure. Pathologic reports revealed inflammatory changes of the appendix (n=386), other pathology (n=11), and no pathologic change (n=18). Overall, 24 patients (5.8%) were readmitted for intra-abdominal abscess (n=14), umbilical wound infection (n=3), and other reasons (n=7). Twelve patients (2.9%) underwent reoperation: drainage of intra-abdominal abscess (n=8) (3 by the surgeon, 5 by the interventional radiologist), wound drainage (n=3), and right hemicolectomy for carcinoid (n=1). In perforated appendicitis the postoperative intra-abdominal abscess rate was 10 of 79 cases (12.7%), which is similar to the previous report with conventional laparoscopic appendectomy from our institution (13.6%). The wound infection rate (5 of 79 cases [6.3%]) was also similar to the previously report (6.8%) with conventional laparoscopic appendectomy for perforated appendicitis. CONCLUSIONS Appendectomy can be accomplished successfully and safely using single-incision endosurgery in children with acceptable operative times without leaving any appreciable scar. Additional trocars are infrequently necessary. So far, the intraoperative and postoperative complication rates are comparable to those of triangulated laparoscopic appendectomy.

Cell survival signaling in neuroblastoma.

Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Neuroblastoma tumorigenesis and malignant transformation is driven by overexpression and dominance of cell survival pathways and a lack of normal cellular senescence or apoptosis. Therefore, manipulation of cell survival pathways may decrease the malignant potential of these tumors and provide avenues for the development of novel therapeutics. This review focuses on several facets of cell survival pathways including protein kinases (PI3K, AKT, ALK, and FAK), transcription factors (NF-κB, MYCN and p53), and growth factors (IGF, EGF, PDGF, and VEGF). Modulation of each of these factors decreases the growth or otherwise hinders the malignant potential of neuroblastoma, and many therapeutics targeting these pathways are already in the clinical trial phase of development. Continued research and discovery of effective modulators of these pathways will revolutionize the treatment of neuroblastoma.

FAK Inhibition Abrogates the Malignant Phenotype in Aggressive Pediatric Renal Tumors

Despite the tremendous advances in the treatment of childhood kidney tumors, there remain subsets of pediatric renal tumors that continue to pose a therapeutic challenge, mainly malignant rhabdoid kidney tumors and nonosseous renal Ewing sarcoma. Children with advanced, metastatic, or relapsed disease have a poor disease-free survival rate. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumor development and progression. FAK has been found in other pediatric solid tumors and in adult renal cellular carcinoma, leading to the hypothesis that FAK contributes to pediatric kidney tumors and would affect cellular survival. In the current study, FAK was present and phosphorylated in pediatric kidney tumor specimens. Moreover, the effects of FAK inhibition upon G401 and SK-NEP-1 cell lines were examined using a number of parallel approaches to block FAK, including RNA interference and small-molecule FAK inhibitors. FAK inhibition resulted in decreased cellular survival, invasion and migration, and increased apoptosis. Furthermore, small-molecule inhibition of FAK led to decreased SK-NEP-1 xenograft growth in vivo. These data deepen the knowledge of the tumorigenic process in pediatric renal tumors, and provide desperately needed therapeutic strategies and targets for these rare, but difficult to treat, malignancies. Implications: This study provides a fundamental understanding of tumorigenesis in difficult to treat renal tumors and provides an impetus for new avenues of research and potential for novel, targeted therapies. Mol Cancer Res; 12(4); 514–26. ©2014 AACR.

Preclinical evaluation of engineered oncolytic herpes simplex virus for the treatment of neuroblastoma.

Despite intensive research efforts and therapeutic advances over the last few decades, the pediatric neural crest tumor, neuroblastoma, continues to be responsible for over 15% of pediatric cancer deaths. Novel therapeutic options are needed for this tumor. Recently, investigators have shown that mice with syngeneic murine gliomas treated with an engineered, neuroattenuated oncolytic herpes simplex virus-1 (oHSV), M002, had a significant increase in survival. M002 has deletions in both copies of the γ134.5 gene, enabling replication in tumor cells but precluding infection of normal neural cells. We hypothesized that M002 would also be effective in the neural crest tumor, neuroblastoma. We showed that M002 infected, replicated, and decreased survival in neuroblastoma cell lines. In addition, we showed that in murine xenografts, treatment with M002 significantly decreased tumor growth, and that this effect was augmented with the addition of ionizing radiation. Importantly, survival could be increased by subsequent doses of radiation without re-dosing of the virus. Finally, these studies showed that the primary entry protein for oHSV, CD111 was expressed by numerous neuroblastoma cell lines and was also present in human neuroblastoma specimens. We concluded that M002 effectively targeted neuroblastoma and that this oHSV may have potential for use in children with unresponsive or relapsed neuroblastoma.

Inhibition of FAK and VEGFR-3 binding decreases tumorigenicity in neuroblastoma

Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of tumor development and progression. Vascular endothelial growth factor receptor‐3 (VEGFR‐3), another tyrosine kinase, has also been found to be important in the development of many human tumors including neuroblastoma. Recent reports have found that FAK and VEGFR‐3 interact, and we have previously shown that both of these kinases interact in neuroblastoma. We have hypothesized that interruption of the FAK–VEGFR‐3 interaction would lead to decreased neuroblastoma cell survival. In the current study, we examined the effects of a small molecule, chloropyramine hydrochloride (C4), designed to disrupt the FAK–VEGFR‐3 interaction, upon cellular attachment, migration, and survival in two human neuroblastoma cell lines. We also utilized a murine xenograft model to study the impact of C4 upon tumor growth. In these studies, we showed that disruption of the FAK–VEGFR‐3 interaction led to decreased cellular attachment, migration, and survival in vitro. In addition, treatment of murine xenografts with chloropyramine hydrochloride decreased neuroblastoma xenograft growth. Further, this molecule acted synergistically with standard chemotherapy to further decrease neuroblastoma xenograft growth. The findings from this current study help to further our understanding of the regulation of neuroblastoma tumorigenesis, and may provide novel therapeutic strategies and targets for neuroblastoma and other solid tumors of childhood.

Preclinical Evaluation of Engineered Oncolytic Herpes Simplex Virus for the Treatment of Pediatric Solid Tumors

Recently, investigators showed that mice with syngeneic murine gliomas that were treated with a neuroattenuated oncolytic herpes simplex virus-1 (oHSV), M002, had a significant increase in survival. M002 has deletions in both copies of the γ134.5 gene, enabling replication in tumor cells but precluding infection of normal cells. Previous studies have shown antitumor effects of other oHSV against a number of adult tumors including hepatocellular carcinoma and renal cell carcinoma. The purpose of the current study was to investigate the oncolytic potential of M002 against difficult to treat pediatric liver and kidney tumors. We showed that the oHSV, M002, infected, replicated, and decreased cell survival in hepatoblastoma, malignant rhabdoid kidney tumor, and renal sarcoma cell lines. In addition, we showed that in murine xenografts, treatment with M002 significantly increased survival and decreased tumor growth. Finally, these studies showed that the primary entry protein for oHSV, CD111 (nectin-1) was present in human hepatoblastoma and malignant rhabdoid kidney tumor specimens. We concluded that M002 effectively targeted these rare aggressive tumor types and that M002 may have potential for use in children with unresponsive or relapsed pediatric solid tumors.

Focal adhesion kinase and p53 synergistically decrease neuroblastoma cell survival.

Neuroblastoma is the most common extracranial solid tumor of childhood and is responsible for over 15% of pediatric cancer deaths. Focal adhesion kinase (FAK) is a nonreceptor tyrosine kinase that is important in many facets of neuroblastoma tumor development and progression. The p53 oncogene, although wild type in most neuroblastomas, lacks significant function as a tumor suppressor in these tumors. Recent reports have found that FAK and p53 interact in some tumor types. We have hypothesized FAK and p53 coordinately control each others expression and also interact in neuroblastoma. In the present study, we showed that not only do FAK and p53 interact but each one controls the expression of the other. In addition, we also examined the effects of FAK inhibition combined with p53 activation in neuroblastoma and showed that these two, in combination, had a synergistic effect on neuroblastoma cell survival. The findings from this present study help to further our understanding of the regulation of neuroblastoma tumorigenesis and may provide novel therapeutic strategies and targets for neuroblastoma and other pediatric solid tumors.

Inhibition of the Focal Adhesion Kinase and Vascular Endothelial Growth Factor Receptor-3 Interaction Leads to Decreased Survival in Human Neuroblastoma Cell Lines

Neuroblastoma continues to be a devastating childhood solid tumor and is responsible for over 15% of all childhood cancer‐related deaths. Focal adhesion kinase (FAK) and vascular endothelial growth factor receptor‐3 (VEGFR‐3) are protein tyrosine kinases that are overexpressed in a number of human cancers, including neuroblastoma. These two kinases can directly interact and provide survival signals to cancer cells. In this study, we utilized siRNA to VEGFR‐3 to demonstrate the biologic importance of this kinase in neuroblastoma cell survival. We also used confocal microscopy and immunoprecipitation to show that FAK and VEGFR‐3 bind in neuroblastoma. Finally, employing a 12‐amino‐acid peptide (AV3) specific to VEGFR‐3, we showed that the colocalization between FAK and VEGFR‐3 could be disrupted, and that disruption resulted in decreased neuroblastoma cell survival. These studies provide insight to the FAK–VEGFR‐3 interaction in neuroblastoma and demonstrate its importance in this tumor type. Focusing upon the FAK–VEGFR‐3 interaction may provide a novel therapeutic target for the development of new strategies for treatment of neuroblastoma.