Competing Engagement of β-arrestin Isoforms Balances IGF1R/p53 Signaling and Controls Melanoma Cell Chemotherapeutic Responsiveness

Constraints on the p53 tumor suppressor pathway have long been associated with the progression, therapeutic resistance, and poor prognosis of melanoma, the most aggressive form of skin cancer. Likewise, the insulin-like growth factor type 1 receptor (IGF1R) is recognized as an essential coordinator of transformation, proliferation, survival, and migration of melanoma cells. Given that β-arrestin (β-arr) system critically governs the anti/pro-tumorigenic p53/IGF1R signaling pathways through their common E3 ubiquitin-protein ligase MDM2, we explore whether unbalancing this system downstream of IGF1R can enhance the response of melanoma cells to chemotherapy. Altering β-arr expression demonstrated that both β-arr1-silencing and β-arr2-overexpression (-β-arr1/+β-arr2) facilitated nuclear-to-cytosolic MDM2 translocation accompanied by decreased IGF1R expression, while increasing p53 levels, resulting in reduced cell proliferation/survival. Imbalance towards β-arr2 (-β-arr1/+β-arr2) synergizes with the chemotherapeutic agent, dacarbazine, in promoting melanoma cell toxicity. In both 3D spheroid models and in vivo in zebrafish models, this combination strategy, through dual IGF1R downregulation/p53 activation, limits melanoma cell growth, survival and metastatic spread. In clinical settings, analysis of the TCGA-SKCM patient cohort confirms β-arr1-/β-arr2+ imbalance as a metastatic melanoma vulnerability that may enhance therapeutic benefit. Our findings suggest that under steady-state conditions, IGF1R/p53-tumor promotion/suppression status-quo is preserved by β-arr1/2 homeostasis. Biasing this balance towards β-arr2 can limit the protumorigenic IGF1R activities while enhancing p53 activity, thus reducing multiple cancer-sustaining mechanisms. Combined with other therapeutics, this strategy improves patient responses and outcomes to therapies relying on p53 or IGF1R pathways.

IMPLICATIONS

Altogether, β-arrestin system bias downstream IGF1R is an important metastatic melanoma vulnerability that may be conductive for therapeutic benefit.

EXPERIMENTAL INDUCTION OF TYPE 2 DIABETES MELLITUS AND THE EFFICIENCY OF BARIATRIC SURGERY IN ITS REVERSAL IN RATS

BACKGROUND

Following recent years, there is an increased body of literature on the connections that might exist between type 2 diabetes mellitus and the efficiency of bariatric surgery in its reversal compared to other medical approaches such as dieting.

AIM

To induce experimentally type 2 diabetes mellitus in rats in order to observe the effects of bariatric surgery in the recovery as well as the reestablishment of normal insulin levels in order to extend the findings in house animals.

MATERIALS AND METHODS

This study was conducted in three stages: the first consisted in inducing type 2 diabetes mellitus (T2DM) in 40 young Wistar male rats, by initially feeding them human food high in vegetal fats, oleaginous seeds, simple and complex carbohydrates, sugars, lipids, fats, proteins and fructose for a period of 8 weeks followed by a single low dose of streptozotocin (STZ), administered through intraperitoneal injection. The second stage of the study started when the rats became obese and therefore qualified for the bariatric procedure and the third stage consisted of post-operation supervision and care. The surgical procedure, performed on 10 obese rats, consisted in reducing the size of the stomach by partial gastrectomy of a 1.5 - 2.0 cm wide and 6.5 - 7.5 cm long area on the large curvature.

RESULTS

Showed rapid improvements in body weight and blood sugar control after 9 days.

CONCLUSION

After putting the rats on a diet high in carbohydrates, sugars, lipids and fats and administering them STZ, the induction of type 2 diabetes was successful and the partial gastrectomy led to a better blood sugar control. The bariatric procedure provides a faster therapeutic response than conventional diets.

Below the Surface: IGF-1R Therapeutic Targeting and Its Endocytic Journey

Ligand-activated plasma membrane receptors follow pathways of endocytosis through the endosomal sorting apparatus. Receptors cluster in clathrin-coated pits that bud inwards and enter the cell as clathrin-coated vesicles. These vesicles travel through the acidic endosome whereby receptors and ligands are sorted to be either recycled or degraded. The traditional paradigm postulated that the endocytosis role lay in signal termination through the removal of the receptor from the cell surface. It is now becoming clear that the internalization process governs more than receptor signal cessation and instead reigns over the entire spatial and temporal wiring of receptor signaling. Governing the localization, the post-translational modifications, and the scaffolding of receptors and downstream signal components established the endosomal platform as the master regulator of receptor function. Confinement of components within or between distinct organelles means that the endosome instructs the cell on how to interpret and translate the signal emanating from any given receptor complex into biological effects. This review explores this emerging paradigm with respect to the cancer-relevant insulin-like growth factor type 1 receptor (IGF-1R) and discusses how this perspective could inform future targeting strategies.

Combined use of antifibrinolytics and activated prothrombin complex concentrate (aPCC) is not related to thromboembolic events in patients with acquired haemophilia A: data from FAIR Registry

Antifibrinolytics combined with aPCC are not routinely administered to patients with acquired hemophilia A due to increased thrombotic risk. This association normalizes clot stability, and improves the efficacy of therapy, but can increase the risk of severe side effects. Due to these premises it has always raised doubts and perplexities in the clinics. We now report the data of the "FEIBA® on acquired haemophilia A Italian Registry (FAIR Registry)", a retrospective-prospective study that included 56 patients. This is the first study that assessed the clinical response of the combination of aPCC and antifibrinolytic agents in patients with acquired haemophilia A. A total of 101 acute bleeds were treated with aPCC. Antifibrinolytic agents were used in the treatment of 39.6% of total bleeds, based on both, a clinical assessment and an evaluation of bleeding. Twenty-five of the 30 patients (57.1%) treated with antifibrinolytic drugs showed serious co-morbidity. Among them, 40% presented severe cardiovascular diseases. All bleeds treated with combined therapy had a shorter duration of treatment (mean reduction 16.3%). All the treated patients presented a good tolerability and no arterial or venous thromboembolic events were reported. In our retrospective registry the combination of antifibrinolytics and aPCC appears safe and effective in the treatment of patients with AHA, especially in the case of severe and life-threatening bleeding, but this hypothesis needs to be confirmed in adequate, larger clinical trials.

Clinical course of patients with symptomatic isolated superficial vein thrombosis: the ICARO follow-up study

Essentials Late sequelae of isolated superficial vein thrombosis (iSVT) have rarely been investigated. We studied 411 consecutive outpatients with acute iSVT with a median follow-up of three years. Male sex and cancer are risk factors for future deep vein thrombosis or pulmonary embolism. Patients without cancer appear to be at a negligible risk for death.

SUMMARY

Background Studies of long-term thromboembolic complications and death following acute isolated superficial vein thrombosis (iSVT) of the lower extremities are scarce. Objectives To investigate the course of iSVT in the setting of an observational multicenter study. Methods We collected longitudinal data of 411 consecutive outpatients with acute, symptomatic, objectively diagnosed iSVT who were previously included in the cross-sectional ICARO study. Four patients followed for < 30 days and 79 with concomitant deep vein thrombosis (DVT) or pulmonary embolism (PE) were excluded from the present analysis. The primary outcome was symptomatic DVT or PE. The safety outcomes were major bleeding and all-cause death. Results The median follow-up time was 1026 days (interquartile range 610-1796). Symptomatic DVT/PE occurred in 52 (12.9%) patients, giving annualized rates of 1.3% (95% confidence interval [CI] 0.3-3.9%) on anticoagulant treatment and 4.4% (95% CI 3.2-5.8%) off anticoagulant treatment. Male sex (adjusted hazard ratio [HR] 2.03 [95% CI 1.16-3.54]) and active solid cancer (adjusted HR 3.14 [95% CI 1.11-8.93]) were associated with future DVT/PE, whereas prior DVT/PE failed to show significance, most likely because of bias resulting from prolonged anticoagulant treatment. Three major bleeding events occurred on treatment, giving an annualized rate of 1.4% (95 CI 0.3-4.0%). Death was recorded in 16 patients (annualized rate: 1.1% [95% CI 0.6-1.7%]), and was attributable to cancer (n = 8), PE (n = 1), cardiovascular events (n = 3), or other causes (n = 4). Conclusions The long-term risk of DVT/PE after anticoagulant discontinuation for acute iSVT is clinically relevant, especially in males and in the presence of active cancer. The risk of death appears to be negligible in patients without cancer.

Recurrent venous thromboembolism in anticoagulated patients with cancer: management and short-term prognosis

BACKGROUND

Recommendations for management of cancer-related venous thromboembolism (VTE) in patients already receiving anticoagulant therapy are based on low-quality evidence. This international registry sought to provide more information on outcomes after a breakthrough VTE in relation to anticoagulation strategies.

METHODS

Patients with cancer and VTE despite anticoagulant therapy were reported to the registry. Data on treatments, VTE events, major bleeding, residual thrombosis symptoms and death were collected for the following 3 months. Breakthrough VTE and subsequent recurrences were objectively verified. Outcomes with different treatment strategies were compared with Cox proportional hazards regression.

RESULTS

We registered 212 patients with breakthrough VTE. Of those, 59% had adenocarcinoma and 73% had known metastases. At the time of the breakthrough event, 70% were on low-molecular-weight heparin (LMWH) and 27% on a vitamin K antagonist (VKA); 70% had a therapeutic or supratherapeutic dose. After breakthrough the regimen was: unchanged therapeutic dose in 33%, dose increased in 31%, switched to another drug in 24%; and other management in 11%. During the following 3 months 11% had another VTE, 8% had major bleeding and 27% died. Of the survivors, 74% had residual thrombosis symptoms. Additional VTE recurrence was less common with LMWH than with a VKA (hazard ratio [HR], 0.28; 95% confidence interval [CI], 0.11-0.70) but similar with unchanged or increased anticoagulant intensity (HR, 1.09; 95% CI, 0.45-2.63). The bleeding rate did not increase significantly with dose escalation.

CONCLUSION

Morbidity and mortality are high after recurrence of cancer-related VTE despite anticoagulation. Further treatment appears to be more effective with LMWH than with a VKA.

A prognostic score to identify low-risk outpatients with acute deep vein thrombosis in the lower limbs

BACKGROUND

No prior studies have identified which patients with deep vein thrombosis in the lower limbs are at a low risk for adverse events within the first week of therapy.

METHODS

We used data from the Registro Informatizado de la Enfermedad TromboEmbólica (RIETE) to identify patients at low risk for the composite outcome of pulmonary embolism, major bleeding, or death within the first week. We built a prognostic score and compared it with the decision to treat patients at home.

RESULTS

As of December 2013, 15,280 outpatients with deep vein thrombosis had been enrolled. Overall, 5164 patients (34%) were treated at home. Of these, 12 (0.23%) had pulmonary embolism, 8 (0.15%) bled, and 4 (0.08%) died. On multivariable analysis, chronic heart failure, recent immobility, recent bleeding, cancer, renal insufficiency, and abnormal platelet count independently predicted the risk for the composite outcome. Among 11,430 patients (75%) considered to be at low risk, 15 (0.13%) suffered pulmonary embolism, 22 (0.19%) bled, and 8 (0.07%) died. The C-statistic was 0.61 (95% confidence interval [CI], 0.57-0.65) for the decision to treat patients at home and 0.76 (95% CI, 0.72-0.79) for the score (P = .003). Net reclassification improvement was 41% (P < .001). Integrated discrimination improvement was 0.034 for the score and 0.015 for the clinical decision (P < .001).

CONCLUSIONS

Using 6 easily available variables, we identified outpatients with deep vein thrombosis at low risk for adverse events within the first week. These data may help to safely treat more patients at home. This score, however, should be validated.

Safety of fondaparinux in the prevention of venous thromboembolism in elderly medical patients: results of a single-center, retrospective study

AIM

Venous thromboembolism (VTE) is one of the leading causes of morbidity and mortality in acutely ill medical patients. Fondaparinux is recommended for the prevention of VTE in this setting, but little information is available on its safety and effectiveness in unselected, "real world" patients. The aim of this paper was to assess the safety and efficacy of fondaparinux in elderly acutely ill medical patients.

METHODS

Single center, retrospective study. All patients >60 years, admitted for acute medical disease, bedridden for at least four days and treated with fondaparinux were evaluated. Occurrence of objectively documented, symptomatic VTE, and of bleeding events during the treatment period and follow-up were reported.

RESULTS

Two hundred and ten patients (median age 81 years) were treated with fondaparinux. Seventy patients received fondaparinux 1.5 mg daily, 140 received the 2.5 mg daily dose. However, 29 patients in the first group (with a CrCl≥50 mL/min) and 84 patients in the last group (with a CrCl<50 mL/min) did not receive the correct dose of fondaparinux. During treatment, one episode (0.48%, 95% CI 0.1% to 2.6%) of major bleeding and 6 episodes (2.86%, 95% CI 1.3% to 6.1%) of clinically relevant non major bleeding were recorded. Only one thromboembolic event (0.48%, 95% CI 0.1% to 2.6%) was documented. Thirty-nine patients died; no death was related to VTE, unlike one death was due to major bleeding. Cancer was the only significant predictor of bleeding at statistical analysis.

CONCLUSION

In elderly acutely ill hospitalized medical patients, thromboprophylaxis with fondaparinux 2.5 or 1.5mg daily is safe and effective in preventing VTE without increasing bleeding risk.

Vanishing bile duct syndrome in non-Hodgkin lymphoma: a case report

Non-Hodgkin lymphoma (NHL) related vanishing bile duct syndrome (VBDS) is a rare condition that often leads to liver failure and death. A 64-year-old man with history of rheumatic heart disease complicated by steno-aortic insufficiency, mild mitral stenosis, atrial fibrillation, left kidney damage, bilateral glaucoma, left internal jugular vein thrombosis, bronchopneumonia, NHL type B (stage IV) treated with chemo and radiotherapy was admitted to our department for jaundice with predominantly cholestatic component. Liver biopsy allowed a diagnosis of VBDS and patient was treated with ursodesossicolic acid (UDCA) 20 mg/kg/day associated with prednisone 1 mg/kg/day with a transient decrease of bilirubin and cholestasis, but a rapid worsening of general clinical conditions followed by severe acute liver failure (ALF), unresponsive to pharmacological therapy, leads to death our patient. In our case we supposed that this syndrome represents the paraneoplastic epiphenomenon of NHL with severe duct damage, related to lymphomatous release of toxic cytokines. In our clinical practice we must not forget that VBDS can be related to hepatic damage also induced during NHL. A special attention to abnormal liver function is necessary to diagnose this syndrome, because often the tests are interpreted as disseminated (stage IV) disease and not as a possible expression of VBDS which could, in some cases, be attenuated by UDCA and by steroids therapy.

Practical use of intermittent pneumatic compression as thromboprophylaxis in neurosurgery

Most patients undergoing neurosurgery are considered at increased risk for venous thromboembolism (VTE). Several studies have demonstrate that intracranial surgery, malignancy, leg weakness, prolonged procedures and advanced age can to increase VTE. Use of thromboprophylaxis is recommended to avoid this risk. Low molecular weight heparin (LMWH), low dose unfractionated heparin (LDUH), intermittent pneumatic compression (IPC) and graduated compression stocking (GCS) are commonly used as VTE prophylaxis. This article wants to show the practical use of IPC in neurosurgery, following the guidelines developed by American College of Chest Physicians (ACCP) and used by the most important medical societies such as American Association of Neurological Surgeons (AANS) and European Association of Neurosurgical Societies (EANS). Several studies have demonstrated that IPC use is effective as LMWH, safe and economic.

PBMCs protein expression profile in relapsing IFN-treated multiple sclerosis: A pilot study on relation to clinical findings and brain atrophy

This cross-sectional study investigated with two-dimensional gel electrophoresis coupled to MALDI-TOF and MRI the relationship between PBMCs protein expression profile and whole-brain atrophy in 16 unselected RR-MS IFN-treated patients compared with 6 RR IFN-untreated and 12 matched healthy control subjects. Grey/white matter fraction, T1/T2 lesion load and clinical variables were considered too. Twenty six proteins showed significant differential expression among RR IFN-treated patients and control samples. Four of these (IN35, GANAB, PP1B, SEPT2) resulted correlated with clinical and MRI findings in RR IFN-treated MS patients. Future clinical applications remain to be validated by other techniques and confirmed by a larger study.

Neuroelectric procedure does not discriminate between painful and paresthetic diabetic neuropathy

To investigate whether pain and paresthesias could identify two different subclasses of small-fibre diabetic neuropathy, and to evaluate their relation to the metabolic control, we tested nerve conduction velocity (NCV) of median nerve (sensitive-SM, and motor-MM) and deep peroneal nerve (DP) in 48 diabetics (24 IDDM, 24 NIDDM) reporting pain (group A) or paresthesias (group B) that might be due to diabetic polyneuropathy. Glycated haemoglobin (HbA1c) was also assessed. No difference between group A and group B was found either in NCV, in all nerves tested, or in HbA1c. No relation was observed between NCV of nerves tested and HbA1c, duration of diabetes, age and type of diabetes in both groups.