Therapeutic targeting of the RB1 pathway in retinoblastoma with the oncolytic adenovirus VCN-01

Retinoblastoma is a pediatric solid tumor of the retina activated upon homozygous inactivation of the tumor suppressor RB1 VCN-01 is an oncolytic adenovirus designed to replicate selectively in tumor cells with high abundance of free E2F-1, a consequence of a dysfunctional RB1 pathway. Thus, we reasoned that VCN-01 could provide targeted therapeutic activity against even chemoresistant retinoblastoma. In vitro, VCN-01 effectively killed patient-derived retinoblastoma models. In mice, intravitreous administration of VCN-01 in retinoblastoma xenografts induced tumor necrosis, improved ocular survival compared with standard-of-care chemotherapy, and prevented micrometastatic dissemination into the brain. In juvenile immunocompetent rabbits, VCN-01 did not replicate in retinas, induced minor local side effects, and only leaked slightly and for a short time into the blood. Initial phase 1 data in patients showed the feasibility of the administration of intravitreous VCN-01 and resulted in antitumor activity in retinoblastoma vitreous seeds and evidence of viral replication markers in tumor cells. The treatment caused local vitreous inflammation but no systemic complications. Thus, oncolytic adenoviruses targeting RB1 might provide a tumor-selective and chemotherapy-independent treatment option for retinoblastoma.

Tissue Compatibility of SN-38-Loaded Anticancer Nanofiber Matrices

Delivery of chemotherapy in the surgical bed has shown preclinical activity to control cancer progression upon subtotal resection of pediatric solid tumors, but whether this new treatment is safe for tumor-adjacent healthy tissues remains unknown. Here, Wistar rats are used to study the anatomic and functional impact of electrospun nanofiber matrices eluting SN-38-a potent chemotherapeutic agent-on several body sites where pediatric tumors such as neuroblastoma, Ewing sarcoma, and rhabdomyosarcoma arise. Blank and SN-38-loaded matrices embracing the femoral neurovascular bundle or in direct contact with abdominal viscera (liver, kidney, urinary bladder, intestine, and uterus) are placed. Foreign body tissue reaction to the implants is observed though no histologic damage in any tissue/organ. Skin healing is normal. Tissue reaction is similar for SN-38-loaded and blank matrices, with the exception of the hepatic capsule that is thicker for the former although within the limits consistent with mild foreign body reaction. Tissue and organ function is completely conserved after local treatments, as assessed by the rotarod test (forelimb function), hematologic tests (liver and renal function), and control of clinical signs. Overall, these findings support the clinical translation of SN-38-loaded nanofiber matrices to improve local control strategies of surgically resected tumors.

The BACE1 product sAPPβ induces ER stress and inflammation and impairs insulin signaling

OBJECTIVE

β-secretase/β-site amyloid precursor protein (APP)-cleaving enzyme 1 (BACE1) is a key enzyme involved in Alzheimer's disease that has recently been implicated in insulin-independent glucose uptake in myotubes. However, it is presently unknown whether BACE1 and the product of its activity, soluble APPβ (sAPPβ), contribute to lipid-induced inflammation and insulin resistance in skeletal muscle cells.

MATERIALS/METHODS

Studies were conducted in mouse C2C12 myotubes, skeletal muscle from Bace1^-/-mice and mice treated with sAPPβ and adipose tissue and plasma from obese and type 2 diabetic patients.

RESULTS

We show that BACE1 inhibition or knockdown attenuates palmitate-induced endoplasmic reticulum (ER) stress, inflammation, and insulin resistance and prevents the reduction in Peroxisome Proliferator-Activated Receptor γ Co-activator 1α (PGC-1α) and fatty acid oxidation caused by palmitate in myotubes. The effects of palmitate on ER stress, inflammation, insulin resistance, PGC-1α down-regulation, and fatty acid oxidation were mimicked by soluble APPβ in vitro. BACE1 expression was increased in subcutaneous adipose tissue of obese and type 2 diabetic patients and this was accompanied by a decrease in PGC-1α mRNA levels and by an increase in sAPPβ plasma levels of obese type 2 diabetic patients compared to obese non-diabetic subjects. Acute sAPPβ administration to mice reduced PGC-1α levels and increased inflammation in skeletal muscle and decreased insulin sensitivity.

CONCLUSIONS

Collectively, these findings indicate that the BACE1 product sAPPβ is a key determinant in ER stress, inflammation and insulin resistance in skeletal muscle and gluconeogenesis in liver.

VLDL and apolipoprotein CIII induce ER stress and inflammation and attenuate insulin signalling via Toll-like receptor 2 in mouse skeletal muscle cells

AIM/HYPOTHESIS

Here, our aim was to examine whether VLDL and apolipoprotein (apo) CIII induce endoplasmic reticulum (ER) stress, inflammation and insulin resistance in skeletal muscle.

METHODS

Studies were conducted in mouse C2C12 myotubes, isolated skeletal muscle and skeletal muscle from transgenic mice overexpressing apoCIII.

RESULTS

C2C12 myotubes exposed to VLDL showed increased levels of ER stress and inflammatory markers whereas peroxisome proliferator-activated receptor γ co-activator 1α (PGC-1α) and AMP-activated protein kinase (AMPK) levels were reduced and the insulin signalling pathway was attenuated. The effects of VLDL were also observed in isolated skeletal muscle incubated with VLDL. The changes caused by VLDL were dependent on extracellular signal-regulated kinase (ERK) 1/2 since they were prevented by the ERK1/2 inhibitor U0126 or by knockdown of this kinase by siRNA transfection. ApoCIII mimicked the effects of VLDL and its effects were also blocked by ERK1/2 inhibition, suggesting that this apolipoprotein was responsible for the effects of VLDL. Skeletal muscle from transgenic mice overexpressing apoCIII showed increased levels of some ER stress and inflammatory markers and increased phosphorylated ERK1/2 levels, whereas PGC-1α levels were reduced, confirming apoCIII effects in vivo. Finally, incubation of myotubes with a neutralising antibody against Toll-like receptor 2 abolished the effects of apoCIII on ER stress, inflammation and insulin resistance, indicating that the effects of apoCIII were mediated by this receptor.

CONCLUSIONS/INTERPRETATION

These results imply that elevated VLDL in diabetic states can contribute to the exacerbation of insulin resistance by activating ERK1/2 through Toll-like receptor 2.

PPARβ/δ and lipid metabolism in the heart

Cardiac lipid metabolism is the focus of attention due to its involvement in the development of cardiac disorders. Both a reduction and an increase in fatty acid utilization make the heart more prone to the development of lipotoxic cardiac dysfunction. The ligand-activated transcription factor peroxisome proliferator-activated receptor (PPAR)β/δ modulates different aspects of cardiac fatty acid metabolism, and targeting this nuclear receptor can improve heart diseases caused by altered fatty acid metabolism. In addition, PPARβ/δ regulates glucose metabolism, the cardiac levels of endogenous antioxidants, mitochondrial biogenesis, cardiomyocyte apoptosis, the insulin signaling pathway and lipid-induced myocardial inflammatory responses. As a result, PPARβ/δ ligands can improve cardiac function and ameliorate the pathological progression of cardiac hypertrophy, heart failure, cardiac oxidative damage, ischemia-reperfusion injury, lipotoxic cardiac dysfunction and lipid-induced cardiac inflammation. Most of these findings have been observed in preclinical studies and it remains to be established to what extent these intriguing observations can be translated into clinical practice. This article is part of a Special Issue entitled: Heart Lipid Metabolism edited by G.D. Lopaschuk.

miR-146a targets Fos expression in human cardiac cells

miR-146a is a microRNA whose transcript levels are induced in the heart upon activation of NF-κB, a transcription factor induced by pro-inflammatory molecules (such as TNF-α) that is strongly related to the pathogenesis of cardiac disorders. The main goal of this study consisted of studying new roles of miR-146a in cardiac pathological processes caused by the pro-inflammatory cytokine TNF-α. Our results demonstrate that miR-146a transcript levels were sharply increased in cardiac ventricular tissue of transgenic mice with specific overexpression of TNF-α in the heart, and also in a cardiomyocyte cell line of human origin (AC16) exposed to TNF-α. Among all the in silico predicted miR-146a target genes, Fos mRNA and protein levels notably decreased after TNF-α treatment or miR-146a overexpression. These changes correlated with a diminution in the DNA-binding activity of AP-1, the Fos-containing transcription factor complex. Interestingly, AP-1 inhibition was accompanied by a reduction in matrix metalloproteinase (MMP)-9 mRNA levels in human cardiac cells. The specific regulation of this MMP by miR-146a was further confirmed at the secretion and enzymatic activity levels, as well as after anti-miR-mediated miR-146a inhibition. The results reported here demonstrate that Fos is a direct target of miR-146a activity and that downregulation of the Fos–AP-1 pathway by miR-146a has the capacity to inhibit MMP-9 activity. Given that MMP-9 is an AP-1 target gene involved in cardiac remodeling, myocardial dysfunction and progression of heart failure, these findings suggest that miR-146a might be a new and promising therapeutic tool for treating cardiac disorders associated with enhanced inflammation in the heart.

Summary: These findings demonstrate that Fos is a direct target of miR-146a activity and that downregulation of the Fos–AP-1 pathway by miR-146a can inhibit MMP-9 activity.

EMLA and Lidocaine Spray: A Comparison for Surgical Debridement in Venous Leg Ulcers

Objective: In this study the author proposes to compare eutectic mixture of local anesthetics (EMLA) and an odontoiatric spray solution of 10% Lidocaine (Ecocain) for surgical debridement in venous leg ulcers. Approach: Fifty patients were recruited and randomly assigned into two groups (A, B). All of them have venous leg ulcer in the medial and/or lateral malleolar region. Group A: topical anesthetic EMLA with film occlusion. Group B: topical anesthesia with Ecocain. The author proceeded to surgical debridement after local anesthesia. A questionnaire and a visual analog scale (VAS) were administered to assess the amount of pain felt during the debridement and during the following 6 h. Results: The analysis of the VAS revealed no major significant differences statistically. The analysis of the questionnaires showed patients treated with Ecocain took more analgesic drugs. Analysis of the timing and quality of procedure showed that Ecocain reduced the timing of debridement and dressing change, improving the outpatient management and patient compliance. Innovations: For rapid debridement, the most appropriate is to use Ecocain. Conclusion: Methods of local anesthesia are multiple and must be identified according to the needs of the patient and the surgeon trying to get the best anesthesia with minimal use of time and resources.

Octyl-2-cyanoacrylate adhesive for skin closure: eight years experience

Cyanoacrylate skin adhesive is increasingly used to ensure and stabilize wound closures. One of the documented favorable effects of these glues is to limit the risk of a surgical site infection by physically isolating the wound.

PATIENTS AND METHODS

From January 2005 to January 2013, 900 patients requiring surgical treatment in the Structure of Plastic Surgery of the University of Sienna were enrolled for the study and divided in two groups; 450 patients treated with glue versus 450 controls.

RESULTS

The cohort of patients treated with glue had lower incidence of wound infection and wound dehiscence. Approximately 375 work-hours were economized.

CONCLUSION

Octyl-2-cyanoacrylate is a valuable aid for ensuring the success of surgery by reducing surgical site infections. The use of octyl-2-cyanoacrylate is easy, guarantying a major superficial protection without relevant contraindications and with evident saving of time and resources.

Postsurgical pain related to breast implant: reduction with lipofilling procedure

BACKGROUND

After a review of clinical cases of the Unit of Plastic Surgery of the University of Siena, Italy, we found that 22 patients undergoing lipofilling for breast recontruction needed less pain drugs compared to 18 patients which did not undergo lipofilling. In this work, the postoperative pain was analyzed in two groups of patients: a cohort treated with prosthesis and a cohort treated with prosthesis implant together with a lipofilling procedure.

PATIENTS AND METHODS

During the immediate postoperative period, a visual analog scale for pain was submitted to every patient every eight hours until they were discharged, then every day for a week, every two days during the second week and once a week in the first three months. The administration of analgesics was also registered.

RESULTS

Pain intensity was lower in the group treated with prosthesis and lipofilling.

CONCLUSION

Fat transplant is a procedure well-tolerated by patients, resulting in a lower rate of pain.