Sareh Parangi

Tissue soldering by use of indocyanine green dye-enhanced fibrinogen with the near infrared diode laser

Anastomoses welded by laser have been strengthened by applying a solder of fibrinogen combined with a laser energy absorbing dye (indocyanine green, maximum absorbance 805 nm) to the anastomotic site before continuous-wave diode laser exposure (808 +/- 1 nm, 4.8 W/cm2). Immediately after creation, the bursting pressures of welds created without fibrinogen (262 +/- 29 mm Hg, n = 11) were significantly less than repairs with fibrinogen (330 +/- 75 mm Hg, n = 11) (p less than 0.05). When repairs performed with fibrinogen were exposed to urokinase (25,000 IU) the bursting pressures were not significantly different from baseline (290 +/- 74 mm Hg, n = 5). Aortotomies closed by suture did not burst but leaked at pressures significantly below those of vessels closed by laser (165 +/- 9 mm Hg, n = 11) (p less than 0.01). Twenty-two repairs soldered with fibrinogen were incorporated into survival studies in rabbits and examined from 1 to 90 days after operation. No anastomotic ruptures, thromboses, or aneurysms were identified. Soldered sites rapidly regenerated a new intimal surface and healed by myofibroblast proliferation. No significant foreign body response was identified; the fibrinogen was resorbed. Laser soldering with exogenous fibrinogen is feasible without topical administration of additional clotting agents, significantly improves the bursting strength of primary laser welded anastomoses, and appears to result from urokinase-resistant fibrinogen cross-linking.

B-Raf(V600E) and thrombospondin-1 promote thyroid cancer progression.

Although B-RafV600E is the most common somatic mutation in papillary thyroid carcinoma (PTC), how it induces tumor aggressiveness is not fully understood. Using gene set enrichment analysis and in vitro and in vivo functional studies, we identified and validated a B-RafV600E gene set signature associated with tumor progression in PTCs. An independent cohort of B-RafV600E-positive PTCs showed significantly higher expression levels of many extracellular matrix genes compared with controls. We performed extensive in vitro and in vivo validations on thrombospondin-1 (TSP-1), because it has been previously shown to be important in the regulation of tumor angiogenesis and metastasis and is present in abundance in tumor stroma. Knockdown of B-RafV600E resulted in TSP-1 down-regulation and a reduction of adhesion and migration/invasion of human thyroid cancer cells. Knockdown of TSP-1 resulted in a similar phenotype. B-RafV600E cells in which either B-RafV600E or TSP-1 were knocked down were implanted orthotopically into the thyroids of immunocompromised mice, resulting in significant reduction in tumor size and fewer pulmonary metastases from the primary carcinoma as compared with the control cells. Treatment of orthotopic thyroid tumors, initiated 1 week after tumor cell implantation with PLX4720, an orally available selective inhibitor of B-RafV600E, caused a significant tumor growth delay and decreased distant metastases, without evidence of toxicity. In conclusion, B-RafV600E plays an important role in PTC progression through genes (i.e., TSP-1) important in tumor invasion and metastasis. Testing of a patients thyroid cancer for B-RafV600E will yield important information about potential tumor aggressiveness and also allow for future use of targeted therapies with selective B-RafV600E inhibitors, such as PLX4720.

Ultrasound-Guided Percutaneous Thyroid Nodule Core Biopsy: Clinical Utility in Patients with Prior Nondiagnostic Fine-Needle Aspirate

BACKGROUND Five percent to 20% of thyroid nodule fine-needle aspiration (FNA) samples are nondiagnostic. The objective of this study was to determine whether a combination of FNA and core biopsy (CFNACB) would yield a higher proportion of diagnostic readings compared with FNA alone in patients with a history of one or more prior nondiagnostic FNA readings. METHODS We conducted a retrospective study of 90 core biopsies (CBs) performed in 82 subjects (55 women and 27 men) between 2006 and 2008 in an outpatient clinic. RESULTS CFNACB yielded a diagnostic reading in 87%. The diagnostic reading yield of the CB component of CFNACB was significantly superior to the concurrent FNA component, with CB yielding a diagnosis in 77% of cases and FNA yielding a diagnosis in 47% (p<0.0001). The combination of CB and FNA had a higher diagnostic reading yield than either alone. In 69 nodules that had only one prior nondiagnostic FNA, CB was diagnostic in 74%, FNA was diagnostic in 52%, CFNACB was diagnostic in 87%, and CB performed significantly better than FNA (p=0.0135). In 21 nodules with two or more prior nondiagnostic FNAs, CFNACB and CB were diagnostic in 86%, FNA was diagnostic in 29%, and CB was significantly better than FNA (p=0.0005). Clinical, ultrasound, or histopathologic follow-up was available for 81% (73/90) of the CFNACB procedures. No subject with a benign CFNACB reading was diagnosed with thyroid malignancy in the follow-up period (range 4-37 months, mean 18 months), although one subject had minimal increase in nodule size and was awaiting repeat sonography at study conclusion. CONCLUSION Thyroid nodule CFNACB is safe and clinically useful in selected patients when a prior FNA reading is nondiagnostic. CFNACB is superior to either CB or FNA alone. CFNACB should be strongly considered as an alternative to surgery in individuals with two prior nondiagnostic FNAs.

Effect of rapamycin alone and in combination with antiangiogenesis therapy in an orthotopic model of human pancreatic cancer

Purpose: The overall 5-year survival of patients with pancreatic cancer remains <5%. Novel therapeutic strategies are needed. We examined the effect of rapamycin, alone and in combination with antiangiogenesis therapy, on pancreatic cancer in vivo. Experimental Design: Human pancreatic cancer AsPC-1 cells were orthotopically injected into severe combined immunodeficient/beige mice to evaluate primary tumor growth and liver metastasis after treatment with rapamycin alone or in combination with anti-vascular endothelial growth factor antibody 2C3. Tumor cell proliferation was determined by bromodeoxyuridine incorporation. To detect tumor cell apoptosis, the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay was used. Tumor angiogenesis was investigated by using a monoclonal anti-CD31 antibody. All statistical tests were two-sided. Results: Rapamycin, alone and in combination with 2C3, strongly inhibited primary and metastatic tumor growth in an orthotopic pancreatic cancer animal model. Furthermore, the combination therapy significantly improved the effect on liver metastasis compared with single treatment with either rapamycin (P = 0.0128) or 2C3 (P = 0.0099). Rapamycin alone inhibited pancreatic tumor cell proliferation, induced apoptosis, and decreased tumor angiogenesis. Nevertheless, the combination therapy showed a significant, stronger inhibition of tumor cell proliferation (P = 0.0002 versus rapamycin alone and P < 0.0001 versus 2C3 alone). The induction of apoptosis was significantly higher than in the rapamycin-treated group (P = 0.0039). Additionally, the combination therapy further improved suppression of tumor cell angiogenesis compared with rapamycin treatment (P = 0.029) Conclusions: Our studies propose new therapeutic strategies to inhibit both primary and metastatic tumor growth in pancreatic cancer. Considering the fact that liver metastasis is a crucial problem in advanced stages of pancreatic cancer, the combination therapy of rapamycin plus anti-vascular endothelial growth factor antibody 2C3 is a significant advantage compared with single treatment with rapamycin.

Thrombospondin-1 modulates vascular endothelial growth factor activity at the receptor level

Vascular endothelial growth factor (VEGF) is a well‐established stimulator of vascular permeability and angiogenesis, whereas thrombospondin‐1 (TSP‐1) is a potent angiogenic inhibitor. In this study, we have found that the TSP‐1 receptors CD36 and ßl integrin associate with the VEGF receptor 2 (VEGFR2). The coclustering of receptors that regulate angiogenesis may provide the endothelial cell with a platform for integration of positive and negative signals in the plane of the membrane. Thus, this complex may represent a molecular switch that regulates angiogenesis and determines endothelial cell behavior. In this context, physiological levels of TSP‐1 appear to support VEGFR2 function on both the cellular and tissue level, because phosphorylation of VEGFR2 and vascular permeability in response to VEGF are decreased in TSP‐1‐null mice and isolated endothelial cells. A therapeutic agent based on the antiangiogenic domain of TSP‐1, designated 3TSR (for three TSP‐1 type 1 repeats), has significant antiangiogenic and antitumor efficacy. Systemic treatment of wild‐type mice with 3TSR significantly decreased VEGF‐induced permeability. Consistent with this result, VEGF‐stimulated phosphorylation of VEGFR2 was also significantly decreased in lung extracts from 3TSR‐treated mice. Moreover, 3TSR significantly decreased VEGF‐stimulated VEGFR2 phosphorylation in human dermal microvascular endothelial cells in culture. Taken together, the results indicate that TSP‐1 and 3TSR modulate the function of VEGFR2.—Zhang, X., Kazerounian, S., Duquette, M., Perruzzi, C., Nagy, J. A., Dvorak, H. J., Parangi, S., and Lawler, J. Thrombospondin‐1 modulates vascular endothelial growth factor activity at the receptor level. FASEB J. 23, 3368–3376 (2009). www.fasebj.org

Targeting BRAFV600E with PLX4720 Displays Potent Antimigratory and Anti-invasive Activity in Preclinical Models of Human Thyroid Cancer

The role of the B-RafV600E mutation in aggressive thyroid cancers is examined.

Is preoperative iodine 123 meta-iodobenzylguanidine scintigraphy routinely necessary before initial adrenalectomy for pheochromocytoma? ☆

BACKGROUND Iodine 123 meta-iodobenzylguanidine (MIBG) scintigraphy has been used in patients with clinical suspicion of pheochromocytoma to confirm the nature of an adrenal or extraadrenal mass or to identify occult disease. Additionally, it may be used to identify unsuspected bilaterality or metastases in the setting of a known unilateral adrenal mass before operation. We sought to determine the role of (123)I MIBG scintigraphy in this apparently routine preoperative setting. Our hypothesis was that (123)I MIBG would provide additional preoperative information that could modify operative intervention. METHODS All patients undergoing (123)I MIBG scintigraphy at our institution between 1992 and 2002 were identified. MIBG results, operative procedures and findings, and pathologic findings were retrospectively reviewed and compared. RESULTS The (123)I MIBG scintigraphy was performed in a total of 315 patients. Of these, 48 were patients with an initial biochemical diagnosis of pheochromocytoma and a unilateral adrenal mass. 47 of the 48 (98%) primary scans were positive for a single focus of activity concordant with anatomic imaging data from computed tomography or magnetic resonance imaging and operative findings. The (123)I MIBG did not reveal unsuspected metastatic or bilateral disease in any patient. CONCLUSION In this large series of patients undergoing (123)I MIBG scintigraphy, the test served only to confirm diagnostic impressions and corroborate anatomic imaging. The (123)I MIBG did not alter the operative management of any patient with a solitary adrenal lesion in the clinical context of biochemically-proven catecholamine excess.

Requirement of different signaling pathways mediated by insulin-like growth factor-I receptor for proliferation, invasion, and VPF/VEGF expression in a pancreatic carcinoma cell line.

Several oncogenes and growth factors are found to be mutated and overexpressed in adenocarcinoma of the pancreas, and may correlate with its highly aggressive nature. Insulin-like growth factor (IGF-I) and its receptor (IGF-IR) are highly expressed in this tumor type. We examined the IGF-IR-mediated signaling pathways in relation to cell proliferation, invasiveness, and expression pattern of vascular permeability factor/vascular endothelial growth factor (VPF/VEGF) in the pancreatic cancer line ASPC-1. Our findings show that IGF-IR is an important growth factor receptor for cell proliferation and invasion, and VPF/VEGF expression in ASPC-1. Further experiments indicate that IGF-IR mediates different signaling pathways to execute its functions. Activation of Ras by IGF-IR was found to be required for the cell invasion. On the other hand Src activation through IGF-IR is required for the cell proliferation, invasion, and also VPF/VEGF expression. Taken together, our data indicate the importance of IGF-IR in growth and invasiveness of the pancreatic cancer cell lines and also point out the multiple signaling pathways channeled through this receptor.

Accuracy of 4-dimensional computed tomography in poorly localized patients with primary hyperparathyroidism

BACKGROUND Four-dimensional computed tomography (4D-CT) utilizes multiplanar images and perfusion characteristics to identify abnormal parathyroid glands. We assessed the role of 4D-CT in patients with inconclusive preoperative ultrasound and sestamibi localization studies. METHODS Adult patients with primary hyperparathyroidism with negative or discordant standard imaging who underwent both localization with 4D-CT and operative intervention for curative intent were included. Patient characteristics, 4D-CT scan results compared with operative findings, and curative proportion were assessed. RESULTS Of the 60 patients, 4D-CT accurately lateralized 73% and localized 60% of abnormal glands found at operation. Single candidate lesions (46/60) were confirmed at operation in 70%. When multiple lesions were identified on 4D-CT (14/60), accuracy dropped to 29% (P = .03). The accuracy of 4D-CT was not different between primary and reoperative cases (P = .79). Of the 8 patients with multigland disease diagnosed perioperatively, 5 had multiple candidate lesions noted on 4D-CT. In 94% (48/51) of patients, a >50% drop in intraoperative parathormone (IOPTH) level was achieved after resection and 87% (48/55) had long-term cure with a median follow-up of 221 days. CONCLUSION 4D-CT identifies the more than half of abnormal parathyroids missed by traditional imaging and should be considered in cases with negative or discordant sestamibi and ultrasound. Bilateral exploration is warranted when multiple candidate lesions are reported on 4D-CT. Multigland disease remains a challenging entity.

BRAF(V600E) and microenvironment in thyroid cancer: a functional link to drive cancer progression.

Papillary thyroid cancer (PTC) rates continue to increase in the United States and Europe, and, although most patients do well, some recur and die of their disease. Patients with PTC harboring the BRAF(V600E) mutation seem to display a more aggressive clinical behavior, but little is known about the role of this mutation in crucial processes in the tumor microenvironment, such as tumor adhesion, migration, invasion, and metastasis. The extracellular matrix (ECM) microenvironment is not merely a structural scaffold for the cellular elements of the epithelial and stromal microenvironment, but it also elicits a profound influence on cell behavior affecting viability, proliferation, adhesion, and motility. The effects of BRAF(V600E) on cell surface receptors (i.e., integrins) and ECM noncellular components [i.e., thrombospondin-1 (TSP-1) and fibronectin (FN)] seem to trigger different pathologic biological processes in a cell context-dependent manner. This review focuses on the recent progress in understanding the role of BRAF(V600E) in the regulation of some ECM noncellular components and trans-membrane receptors of the microenvironment in PTC in order to design novel targeted therapies directed at the BRAF(V600E) multifaceted signaling cascades. Some of these targeted therapeutics, such as ATP-competitive BRAF(V600E) inhibitors (i.e., orally bioavailable PLX4720 and PLX4032 compounds), are already under investigation.