Lindsay J. Talbot

Osteopontin promotes CCL5-mesenchymal stromal cell-mediated breast cancer metastasis

The interaction between cancer and its local microenvironment can determine properties of growth and metastasis. A critical component of the tumor microenvironment in this context is the cancer-associated fibroblast (CAF), which can promote tumor growth, angiogenesis and metastasis. It has been hypothesized that CAF may be derived from mesenchymal stromal cells (MSC), derived from local or distant sources. However, the signaling mechanisms by which tumors and MSCs interact to promote CAF-dependent cancer growth are largely unknown. In this study with in vitro and in vivo models using MDA-MB231 human breast cancer cells, we demonstrate that tumor-derived osteopontin (OPN) induces MSC production of CCL5; the mechanism involves OPN binding to integrin cell surface receptors and activator protein-1 c-jun homodimer transactivation. In a murine xenograft model, concomitant inoculation of MSC with MDA-MB231 cells induces: (i) significantly increased growth and metastasis of MB231 cells and (ii) increased MSC migration to metastatic sites in lung and liver; this mechanism is both OPN and CCL5 dependent. MSCs retrieved from sites of metastases exhibit OPN-dependent expression of the CAF markers, α-smooth muscle actin, tenascin-c, CXCL12 (or stromal cell-derived factor 1) and fibroblast-specific protein-1 and the matrix metalloproteinases (MMP)-2 and MMP-9. Based upon these results, we propose that tumor-derived OPN promotes tumor progression via the transformation of MSC into CAF.

Human mesenchymal stem cell and epithelial hepatic carcinoma cell lines in admixture: Concurrent stimulation of cancer-associated fibroblasts and epithelial-to-mesenchymal transition markers

BACKGROUND The microenvironments of neoplasms influence both mesenchymal stem cell differentiation into cancer-associated fibroblasts (CAF) and tumor cell line differentiation to mesenchymal phenotypes via epithelial-to-mesenchymal transition (EMT). Using direct cell-cell contact approximating the microenvironment of a neoplasm, we investigated the role of this interaction in human mesenchymal stem cells (hMSCs) and epithelial hepatic carcinoma SK-Hep1 cells by evaluating CAF differentiation and EMT. METHODS hMSCs and SK-Hep1 cells were homogenously cultured for 12 hours with media only, OPN-R3 aptamer blockade of OPN, or RGD peptide blockade of integrin receptor, negative control mutant OPN-R3 aptamer, and RGE peptide blockade. mRNA was isolated from each subpopulation, and real-time-polymerase chain reaction was performed for CAF markers and EMT transcription factors and structural proteins. RESULTS SK-Hep1 cells in admixture with hMSCs showed increased EMT marker vimentin expression that was ablated with OPN-R3 aptamer or RGD blockade. SK-Hep1 cells when cultured with hMSC admixture increased Snail and Slug expression that was hindered with OPN-R3 aptamer. hMSCs acquired CAF markers tenascin-c and SDF-1 in admixture that was ablated with either OPN-R3 aptamer or RGD blockade. All SK-Hep1 and hMSC negative control subpopulations were statistically equivalent to media-only groups. Fluorescence photography exhibited the critical cell-cell interfaces and acquired EMT traits of SK-Hep1. CONCLUSION We conclude that direct interaction of cell lines closely replicates the native neoplasm microenvironment. Our experiments reveal soluble OPN or integrin receptor blockade independently prevents progression to metastatic phenotype by acquisition of CAF and EMT markers.

Osteopontin regulates epithelial mesenchymal transition-associated growth of hepatocellular cancer in a mouse xenograft model

Objective: To determine the efficacy of osteopontin (OPN) targeting in hepatocellular cancer (HCC). Summary/Background: OPN is associated with HCC growth and metastasis and represents a unique therapeutic target. Methods: OPN and epithelial-mesenchymal transition (EMT) markers, &agr;-smooth muscle actin (SMA), vimentin, and tenascin-c, were measured in archived human HCC tissues from metastatic (n = 4) and nonmetastatic (n = 4) settings. Additional studies utilized human Sk-Hep-1 (high OPN expression) and Hep3b (low OPN expression) HCC cells. An RNA aptamer (APT) that avidly binds (K d = 18 nM; t 1/2 = 7 hours) and ablates OPN binding was developed. Adhesion, migration/invasion, and EMT markers were determined with APT or a mutant control aptamer (Mu-APT). RFP-Luc-Sk-Hep-1 were implanted into NOD-scid mice livers and followed by using bioluminescence imaging. After verification of tumor growth, at week 3, APT (0.5 mg/kg; n = 4) or Mu-APT (0.5 mg/kg; n = 4) was injected q48h. When mice were killed at week 8, tumor cells were reisolated and assayed for EMT markers. Results: OPN and EMT markers were significantly increased in the metastatic cohort. APT inhibited Sk-Hep-1 adhesion and migration/invasion by 5- and 4-fold, respectively. APT significantly decreased EMT protein markers, SMA, vimentin, and tenascin-c. In contrast, APT did not alter Hep3B adhesion, or migration/invasion. EMT markers were slightly decreased. In the in vivo model, at weeks 6 to 8, APT inhibited HCC growth by more than 10-fold. SMA, vimentin, and tenascin-c mRNAs were decreased by 60%, 40%, and 49%, respectively, in RFP-positive Sk-Hep-1 recovered by fluorescence-activated cell sorting (P < 0.04 vs Mu-APT for all). Conclusions: APT targeting of OPN significantly decreases EMT and tumor growth of HCC.

Factors associated with survival in pediatric adrenocortical carcinoma: An analysis of the National Cancer Data Base (NCDB)

PURPOSE Adrenocortical carcinoma (ACC) is a rare tumor in children with important distinctions from the adult disease. We reviewed the National Cancer Data Base (NCDB) to determine factors associated with long-term survival. METHODS The NCDB was queried for patients less than 18 years of age who were diagnosed with ACC between 1998 and 2011. Kaplan-Meier analysis was utilized to determine factors significantly associated with overall survival. RESULTS A total of 111 patients were included (median age: 4 years, 69% female). ACC was more common in the youngest cohort, with 48% of cases occurring in children younger than the age of 3. Median tumor size was 9.5 cm (IQR: 6.5-13.0), and 87% of patients underwent some form of surgical resection. Among children with available data, 19 of 62 presented with metastases. Overall 1- and 3-year survival was 70% and 64%, respectively. Age, tumor size, extension of tumor into surrounding tissue, and metastatic disease were all found to be significantly associated with survival. Among patients who underwent a surgical procedure, margin status was also found to be significantly associated with survival. CONCLUSION Age, tumor size, extension of tumor, metastatic disease, and margin status are significantly associated with long-term survival in children with adrenocortical carcinoma.

Influence of weight at enterostomy reversal on surgical outcomes in infants after emergent neonatal stoma creation

PURPOSE Neonates after emergent enterostomy creation frequently require reversal at low weight because of complications including cholestasis, dehydration, dumping, failure to thrive, and failure to achieve enteral independence. We investigated whether stoma reversal at low weight (< 2.5kg) is associated with poor surgical outcomes. METHODS Patients who underwent enterostomy reversal from 2005 to 2013 at less than 6months old were identified in our institutional database. Only patients who underwent emergent enterostomy creation (i.e. for necrotizing enterocolitis or spontaneous perforation) were included. Demographics, disease process, comorbidities, stoma type, reversal indication, operative details, and complications were examined. Patients were categorized by weight at reversal of less than 2kg, 2.01-2.5kg, 2.51-3.5kg, and greater than 3.5kg. Data were analyzed using univariable and multivariable regression with significance level of p<0.05. The primary outcome examined was major morbidity, defined as the presence of anastomotic leak, obstruction, hernia, EC fistula, perforation, wound infection, sepsis, or death. RESULTS Eighty-nine patients met inclusion criteria. Demographics (sex, ethnicity, surgical disease process, reversal indication, and ASA score) were similar. The lowest weight group had lower gestational age (p<0.001) and birth weight (p=0.005), and contained a higher proportion of jejunostomies to ileostomies (p=0.013). On univariable analysis, only incisional hernia was significantly different as a complication between weight groups. On multivariable analysis controlling for gestational age and ASA, there was no significant difference in odds of major operative morbidity between groups. CONCLUSIONS Enterostomy reversal at lower weight may not be associated with increased risk of perioperative complications. Early stoma reversal may be acceptable when required for progression of neonatal care. LEVEL OF EVIDENCE Level III, Treatment Study (Retrospective comparative study).

Obesity and trends in malpractice claims for physicians and surgeons

BACKGROUND The increasing prevalence of obesity has altered the practice of medicine and surgery, with the emergence of new operations and medications. We hypothesized that the landscape of medical malpractice claims has also changed. METHODS We queried the Physician Insurers Association of American database for 1990 through 1999 and 2000 through 2009 for cases corresponding to International Classification of Diseases, 9th edition, codes for obesity. We extracted adjudicatory outcome, closed and paid claims data, indemnity payments, primary alleged error codes, National Association of Insurance Commissioners severity of injury class, procedural codes, and medical specialty data. RESULTS A total of 411 obesity claims were filed from 1990 to 1999 and 1,591 obesity claims were filed from 2000 to 2009. General surgery was the specialty with the greatest number of obesity claims from 1990 to 1999 and was second to family practice for 2000 to 2009. Although the percentage of paid general surgery obesity claims has decreased significantly from 69% in 1990-1999 to 36% in 2000-2009, the mean indemnity payments have increased substantially (

Inequalities in the use of helmets by race and payer status among pediatric cyclists

94,000 to

Comparing oncologic outcomes after minimally invasive and open surgery for pediatric neuroblastoma and Wilms tumor

368,000). CONCLUSION Recently, the percentage of paid general surgery obesity claims has significantly decreased; however, individual and total indemnity payments have increased. Obesity continues to impact general surgery malpractice substantially. Efforts to manage this component of physician and hospital practices must continue.

Splenectomy and partial splenectomy improve hematopoietic stem cell engraftment in hypersplenic mice

BACKGROUND Despite nationwide campaigns to increase the use of helmets among pediatric cyclists, many children continue to be injured while riding without a helmet. To determine where programs and policies intended to promote helmet use should be directed, we surveyed a large national dataset to identify variables associated with helmet use. METHODS The National Trauma Data Bank was queried during the years 2007, 2010, and 2011 for children younger than the age of 16 years who were involved in a bicycle accident. Children were grouped based on whether they had a helmet on during the accident. A multivariable logistic mixed-effects model was utilized to determine factors associated with helmet use. RESULTS Of the 7,678 children included in the analysis, 1,695 (22.1%) were wearing a helmet during their accident. On unadjusted analysis, nonhelmeted riders were more likely to be older (median age 11 years vs 10 years, P < .001), black (10.1% vs 3.7%, P < .001) or insured by Medicaid (32.8% vs 14.3%, P < .001). After adjustment, black children were still less likely to have had worn a helmet compared with white children (adjusted odds ratio 0.38, 95% confidence interval 0.28-0.50). Children on Medicaid were also less likely to have been wearing a helmet compared to children with private insurance (adjusted odds ratio 0.33, 95% confidence interval 0.28-0.39). CONCLUSION Children who are black or who are on Medicaid are less likely to be wearing a helmet when involved in a bicycle accident than white children or children with private insurance, respectively. Future efforts to promote helmet use should be directed towards these groups.

Accuracy of Prehospital Care Providers in Determining Total Body Surface Area Burned in Severe Pediatric Thermal Injury

Minimally invasive surgery (MIS) has been widely adopted for common operations in pediatric surgery; however, its role in childhood tumors is limited by concerns about oncologic outcomes. We compared open and MIS approaches for pediatric neuroblastoma and Wilms tumor (WT) using a national database.