Jamie Harris

Implantable chemotherapy-loaded silk protein materials for neuroblastoma treatment.

Neuroblastoma is the most common extracranial childhood solid tumor. Treatment of high risk tumors require intense multicycle chemotherapies, resulting in short‐ and long‐term toxicities. Here, we present treatment of an orthotopic neuroblastoma mouse model, with silk fibroin materials loaded with vincristine, doxorubicin or the combination as a intratumoral, sustained release system. The materials, loaded with vincristine with or without doxorubicin, significantly decreased neuroblastoma tumor growth compared to materials loaded without drug or doxorubicin only as well as intravenous (IV) drug treatment. The intratumoral drug concentration was significantly higher with intratumoral delivery versus IV. Furthermore, intratumor delivery decreased the maximum plasma concentration compared to IV delivery, reducing systemic exposure and possibly reduing long‐term side effects of chemotherapy exposure. Histopathologically, tumors with remission periods >25 days before recurrence transformed from a “small‐round‐blue cell” (SBRC) to predominantly “large cell” neuroblastoma (LCN) histopathology, a more aggressive tumor subtype with unfavorable clinical outcomes. These results show that intratumoral chemotherapy delivery may be a treatment strategy for pediatric neuroblastoma, potentially translatable to other focal tumors types. Furthermore, this treatment modality allows for a clinically relevant mouse model of tumor transformation that may be used for studying the phenotypical tumor recurrence and developing more effective treatment strategies for recurrent tumors.

Clinical Considerations of Focal Drug Delivery in Cancer Treatment

BACKGROUND According to the US Center for Disease Control, cancer deaths are the second most common cause of mortality in both adults and children. Definitive treatment of solid tumors involves surgical resection with or without systemic chemotherapy and radiation. The advent of local drug delivery presents a unique treatment modality that can offer substantial benefits in cancer management. Three main phases in solid tumor management exist for the treating physician: initial diagnosis with tissue biopsy, surgical resection with or without chemotherapy, and management of metastatic disease. METHODS A literature review of both basic science as well as clinical trials using local drug delivery strategies in the management of solid tumors was done on PubMed. These were then further divided into the categories of initial tissue biopsy intervention, surgical resection, and management of metastatic disease. RESULTS A total of 27 articles were review that included both pre-clinical as well as clinical investigation of local drug delivery therapies in the treatment of solid tumors. Treatments such as MRI guided therapies, FDA approved local therapies for intracranial gliomas as well as local therapy for single site metastatic disease were identified. CONCLUSION This review focuses the current state of local drug delivery in the treatment of solid tumors in both the pre-clinical as well as clinical investigation settings. Local drug delivery therapy offers an exciting new treatment modality for solid malignancies.

Overweight and Obese Pediatric Patients Have an Increased Risk of Developing a Surgical Site Infection.

BACKGROUND Obesity is a known risk factor in adult surgical site infections (SSIs), but its significance in pediatrics is unclear. We hypothesized that overweight and obese children have increased risk for SSI. PATIENTS AND METHODS A National Surgical Quality Improvement Program-Pediatric (NSQIP-P) file and single-center reviews identified surgical patients (2-18 years) who developed SSIs. Patients were classified as underweight, normal, overweight, or obese based on body mass index (BMI). Comorbidities associated with SSI were analyzed. Sub-specialties and operations were recorded. RESULTS National Surgical Quality Improvement Program-Pediatric review identified 66,671 patients and 1,380 SSIs. Seven hundred sixty-seven (767) were male and 613 female. Multivariable analysis revealed overweight and obese BMI to be risk factors for SSIs (odds ratio [OR] 1.23, 95% confidence interval [CI] 1.06-1.43; OR 1.43, 95% CI 1.25-1.63). Most commonly, overweight and obese cohorts had superficial incisional SSIs. Pediatric general surgery (3.6%) and cardiothoracic surgery (2.5%) had the highest rates of SSIs. Single-center review identified 115 SSIs. Of these, 29.6% were overweight or obese with few other identifiable SSI risk factors. Sub-specialties with the most SSIs were pediatric surgery and pediatric orthopedics. Appendectomy was the most common procedure associated with SSIs. CONCLUSION Herein we show elevated BMI to be a significant risk factor for SSIs. This information should be used in assessing and counseling pre-operative pediatric patients and families.

Sustained delivery of vincristine inside an orthotopic mouse sarcoma model decreases tumor growth

BACKGROUND Sarcoma accounts for 20% of solid tumors in children. Surgery has significant morbidity. We hypothesized that delivering chemotherapy directly into tumors through sustained release silk systems could slow tumor growth. METHODS Human Ewing sarcoma cells A673 were cultured with vincristine and doxorubicin to determine half maximal inhibitory concentration (IC50). Cells were injected into mouse hind leg to create orthotopic tumors. Tumor volumes were measured using ultrasound. When volume reached >250mm3, interventions included: implantation of drug-free silk foam (Control-F), doxorubicin 400μg foam (Dox400-F), vincristine 50μg foam (Vin50-F), drug-free silk gel (Control-G), vincristine 50μg gel (Vin50-G), or single dose intravenous vincristine 50μg (Vin50-IV). End-point was volume>1000mm3. Kaplan Meier and ANOVA were used. RESULTS IC50 for vincristine and doxorubicin was 0.5ng/mL and 200ng/mL, respectively. There was no difference between Dox400-F [6±1days to end point (DTEP)] and Control-F (5±1.3 DTEP). Vin50-F (12.4±3.5 DTEP) had slower growth compared to Control-F (p<0.001), and there was no difference between Vin50-F and Vin50-IV (14±0 DTEP). Growth was slowest with Vin50-G, 28±10.3 DTEP compared to all other treatment groups (p<0.05). CONCLUSION Sustained delivery of vincristine inside the sarcoma tumor with silk gel decreased tumor growth. Applying this intratumoral treatment strategy may potentially decrease the extent of surgical excision.

Manipulation of variables in local controlled release vincristine treatment in neuroblastoma

INTRODUCTION Local drug delivery minimizes systemic toxicity while delivering high-dose chemotherapy for neuroblastoma patients. We hypothesized that varying burst and maintenance dosing of implanted silk platforms would improve survival. METHODS Platforms were loaded with vincristine 25μg, 50μg, 100μg, and 200μg varying burst (released 1-4days postimplantation) and maintenance (over the next 20days) dosing. Orthotopic tumors were created in mice using human neuroblastoma KELLY cells. Silk platforms were implanted into tumors when volumewas >300mm3. Tumor volume was monitored weekly with ultrasound. Experimental endpoints were tumor volumewas >1000mm3 or weight losswas >25%. RESULTS Drug release ranged from burst dosing of 18.2 to 80.9μg, maintenance of 5.0 to 111.6μg, and cumulative of 23.3 to 177.4μg. Animals treated with 200μg platform died 9-13days postimplantation, corresponding to 128.1-141.2μg released (toxic dose). Animals received 30.2±3.4μgday-one survived longer than those that received 10.1±1.1μg (p=0.03), suggesting <10.1μgday-one was insufficient. Tumors treated with 100μg or 50μg silk platform took longer to reach 1000 mm3 compared to those treated with control, 44.8±9.5days (p<0.001) and 26.7±6.7days (p<0.05), respectively, versus 7.0±1.7days. Overall survival correlated with higher burst (r=0.446, p=0.004) and maintenance dosing (r=0.353, p=0.02), Animal survival days=30.314+0.626 × (dose on day-one) - 0.020×(tumor volume at day-ten) (p<0.05). CONCLUSION Platform formulations can be manipulated to vary burst and maintenance dosing, summarized by an equation consisting of these variables.

Irreversible electroporation as an effective technique for ablating human metastatic osteosarcoma

Irreversible electroporation (IRE) induces apoptosis in tumor cells with electric energy, allowing treatment of unresectable tumors. One potential application is metastatic osteosarcoma (OS) in the pediatric population. A 12-year-old underwent thoracotomy with resection of metastatic OS. IRE was applied to 1 resected tumor section. Using 2 probes, 100 pulses with width of 90 ms were delivered. Efficacy was measured by increase in current draw during treatment. The treated sample was analyzed with hematoxylin and eosin and transmission electron microscopy. Default voltage of 1800 kV was ineffective. Voltage of 2700 kV caused excessive current draw and was aborted to prevent thermal injury. At 2200 kV, current draw rise was 9 amps, signifying successful treatment. Untreated specimen showed viable OS, normal surrounding lung tissue. Treated tumor had edema within the tumor and in surrounding lung tissue, with intra-alveolar hemorrhage and cellular architecture destruction. There was also evidence for cellular destruction such as disruption of lipid bilayer and release of intracellular fluid. Optimal voltage for treatment was 2200 kV, likely higher due to electrical conduction variation in the aerated lung. IRE may be an option for pediatric patients with unresectable metastatic OS.

A Rare Case of Thoracoschisis

A term male baby, after delivery, was found to have a 3-centimeter beefy-red mass protruding from the left chest wall, adjacent to the left nipple. Radiological imaging suggested it’s origin from the left lateral liver segment. A diagnostic laparoscopy confirmed the isolated connection to the liver, elevated left hemidiaphragm, and protrusion between the ribs. The mass was excised using electrocautery, and pathologic examination showed normal liver tissue.

Silencing Intersectin 1 Slows Orthotopic Neuroblastoma Growth in Mice

Neuroblastoma accounts for 15% of all pediatric cancer deaths. Intersectin 1 (ITSN1), a scaffold protein involved in phosphoinositide 3-kinase (PI3K) signaling, regulates neuroblastoma cells independent of MYCN status. We hypothesize that by silencing ITSN1 in neuroblastoma cells, tumor growth will be decreased in an orthotopic mouse tumor model. SK-N-AS neuroblastoma cells transfected with empty vector (pSR), vectors expressing scrambled shRNA (pSCR), or shRNAs targeting ITSN1 (sh#1 and sh#2) were used to create orthotopic neuroblastoma tumors in mice. Volume was monitored weekly with ultrasound. End-point was tumor volume >1000 mm3. Tumor cell lysates were analyzed with anti-ITSN1 antibody by Western blot. Orthotopic tumors were created in all cell lines. Twenty-five days post injection, pSR tumor size was 917.6±247.7 mm3, pSCR was 1180±159.9 mm3, sh#1 was 526.3±212.8 mm3, and sh#2 was 589.2±74.91 mm3. sh#1-tumors and sh#2-tumors were smaller than pSCR (P=0.02), no difference between sh#1 and sh#2. Survival was superior in sh#2-tumors (P=0.02), trended towards improved survival in sh#1-tumors (P=0.09), compared with pSCR-tumors, no difference in pSR tumors. Western blot showed decreased ITSN1 expression in sh#1 and sh#2 compared with pSR and pSCR. Silencing ITSN1 in neuroblastoma cells led to decreased tumor growth in an orthotopic mouse model. Orthotopic animal models can provide insight into the role of ITSN1 pathways in neuroblastoma tumorigenesis.

Duodenal atresia and neonatal cholestasis in R117H cystic fibrosis

Cystic fibrosis (CF) has 20% associated rate of neonatal cholestasis. This presents in classic type CF, which initially can be confused with biliary atresia. Additionally, CF has been described with intestinal atresias but not duodenal atresia (DA). This is a case presentation highlighting a previously unreported presentation of R117H 5T CF mutation: A mutation that has recently been described and is not well-characterized. A retrospective review of single case was done. The newborn screen was sent per protocol. A 32 and 6/7 week gestation male was born with DA. Perinatal testing showed R117H mutation and 5T variant on separate chromosomes. His DA was repaired at 4 weeks of life. He had persistent jaundice, hepatobiliary iminodiacetic acid scan failed to identify the gallbladder, and raising concern for biliary atresia. At laparotomy, biliary tree was found to be normal on cholangiogram. Liver biopsy showed depleted interlobular bile ducts, with cholangiolar proliferation, consistent with CF induced cholestasis. This is an abnormal presentation for CF induced neonatal cholestasis and DA in the R117H 5T mutation that traditionally has been described as mild/atypical presentation of CF. Therefore, patients with this mutation who present with persistently elevated bilirubin should be evaluated for liver disease associated with CF.