Novel Role of Glycogen Synthase Kinase-3β in Determining Cancer Cell Response to Genotoxic Stress through Regulation of 53BP1 Function

PURPOSE/OBJECTIVE(S)

Glycogen synthase kinase-3β (GSK3β) is a multifunctional serine/threonine kinase involved in various cellular processes and signaling pathways. Accumulating evidence suggests GSK3β plays a role in cancer treatment with effects on tumorigenesis and treatment response. We have previously shown that inhibition of GSK3β protects neurons from ionizing radiation-induced apoptosis through upregulation of non-homologous end joining (NHEJ) mediated repair of double strand breaks (DSBs). Here, we investigate the molecular mechanism underlying GSK3β regulation of NHEJ.

MATERIALS/METHODS

Using biochemical, molecular, and genetic approaches, we investigated the physical and functional interaction between GSK3β and 53BP1. Cultured human tumor cells were utilized as model system to further characterize how GSK3β controls 53BP1 function in DNA DSB recognition and repair. Finally, we employed a cell biology approach to genetically and pharmacologically manipulate GSK3β activity and test how the GSK3β-53BP1 axis impacts tumor cytotoxic response to PARP inhibitor (PARPi) and radiation therapy.

RESULTS

We illustrate that GSK3β directly interacts with 53BP1 and phosphorylates 53BP1 at threonine 334 amino acid (T334) within a region heavily phosphorylated by several stress kinases. Phosphorylation at T334 inhibits 53BP1's function in recruitment to DNA DSB sites as well as canonical NHEJ. Furthermore, our results identify GSK3β regulation of 53BP1 function in NHEJ is achieved through suppression of downstream mediators, RIF1 and PTIP, and their function. In contrast, GSK3β enhances single strand DNA resection and promotes homologous recombination (HR) repair. Most importantly, genetic and pharmacologic inhibition of GSK3β-53BP1 signaling axis dramatically enhances the cytotoxic response of BRCA1-deficit cancer cells to PARPi. The assessment of the effect of GSK3β-53BP1 axis on tumor cell response to radiation treatment is underway.

CONCLUSION

This study establishes the connection between GSK3β and DSB repair through its phosphorylation and regulation of 53BP1 pathways. Moreover, it demonstrates that GSK3β kinase activity uniquely results in inhibition of 53BP1 as opposed to other kinases that enhance 53BP1 function. Importantly, this novel signaling axis provides a strategy for targeting cancer cell resistance to PARPi.

Systemic White Blood Cell Count as a Biomarker for Malignant Cerebral Edema in Large Vessel Ischemic MCA Stroke

OBJECTIVES

Large middle cerebral artery (MCA) strokes remain a major cause for mortality and morbidity all over the world, and therefore early identification of patients with the highest risk for malignant cerebral edema is crucial for early intervention. Neutrophils to lymphocytes ratio (NLR) and peripheral total white blood cell (WBC) count are inflammatory markers done routinely for all patients, and this study evaluated the use of NLR and elevated white blood cell count within the first 24 h of MCA ischemic stroke onset, with the absence of significant hemorrhagic transformation, to predict malignant cerebral edema.

MATERIALS AND METHODS

A total of 156 patients with large MCA strokes were included. We collected demographic, clinical, radiological data, and NLR and WBCs within the first 24 h from admission.We excluded patients who had any underlying infections diagnosed 7 days before or within 72 h after admission. We used a body temp of 38 C or more, abnormal CXR or abnormal urine analysis within the first 72 h to exclude patients with possible infections.We excluded immune-compromised patients and patients on steroid therapy. We compared the NLR and WBC count in patients who developed malignant cerebral edema versus the patients who did not. NLR > 3.5 and < 3.5 was used for comparison. We then conducted multivariate logistic regression models to explore the relationship between cerebral edema, WBCs and NLR count simultaneously.

RESULTS

NLR, WBC, radiological involvement of more than 50% of MCA territory infarction on presentation, hyperdense MCA sign, and NIH stroke scale were all significantly higher in patients with malignant cerebral edema within the first 24 h. Using univariate logistic regression, NLR performs better than WBC when predicting the occurrence of malignant cerebral edema (AUC = 0.74 vs. 0.62). However, NIH stroke scale scores, and radiological involvement of more than 50% of MCA territory infarction on the first 24 h of presentation on CT scan both showed better discriminative performance for malignant cerebral edema than NLR (AUC = 0.84 and 0.76, respectively). When combined, NLR > 3.5 paired with the NIH stroke scale score had the best predictive performance (AUC = 0.87).

CONCLUSION

NLR > 3.5 can be used for early prognostication in patients with large vessel MCA ischemic strokes with no significant hemorrhagic transformation within the first 24 h regardless if they had reperfusion therapy or not. Combining NLR of > 3.5 in addition to high NIHSS provided the best predictive model in our study. Further studies are needed to further develop the best predictive model in diverse populations.

Trans-arterial therapy for Fibrolamellar carcinoma: A case report and literature review

Introduction

Fibrolamellar carcinoma (FLC) is a rare pathologically distinct primary liver cancer. Surgical resection is the only treatment associated with prolonged survival. Trans-arterial embolization (TAE), which is a recognised treatment for hepatocellular carcinoma has been used to treat FLC. We present a case and performed a literature review of patients with FLC treated with TAE.

Case presentation

We present a 19-year old female with a large potentially resectable FLC which was initially treated with trans-arterial chemo-embolization (TACE) with drug eluting beads. The TACE was followed by surgical resection. Histology confirmed tumour necrosis related to the previous TACE.

Discussion & literature review

We identified seven case reports and one case series of TAE for FLC. TAE was either used as a neo-adjuvant therapy to facilitate subsequent tumour resection or as a palliative treatment modality. We propose an algorithm for the treatment of FLC that includes TAE.

Conclusion

The rarity of FLC and the paucity of data precludes establishing clear evidence-based standards of care. We propose an algorithm for the treatment of FLC. The establishment of an international registry may facilitate the collection of better quality evidence.

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Fibrolamellar carcinoma (FLC) is a rare primary liver tumour that predominantly occurs in young patients.

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Surgical resection of the tumour and liver transplantation are the only potentially curative treatment modalities.

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Trans-arterial embolization has been used as neo-adjuvant and palliative treatment modalities.

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We propose a management algorithm which includes trans-arterial embolization for selected patients with FLC.

COVID-19 and stroke, a case series and review of literature

BACKGROUND

Corona Virus Disease 2019 (COVID-19) cases continue to increase around the World. Typical symptoms include fever and respiratory illness but a constellation of multisystem involvement including central nervous system (CNS) and peripheral nervous system (PNS) have been reported with COVID-19. Acute ischemic strokes (AIS) have also been reported as a complication.

METHODOLOGY

We analyzed patient characteristics, clinical outcomes, laboratory results and imaging results of four patients with COVID-19 who had AIS.

RESULTS

All four patients were =< 60 years, had hypoxemic respiratory failure secondary to pneumonia, elevated D-dimer and inflammatory markers.

CONCLUSION

Ischemic strokes are known complications in patients with severe COVID-19.

Traumatic carotid-rosenthal fistula treated with Jostent Graftmaster

Traumatic injuries of the carotid artery may result in severe morbidity and mortality. The most common location of carotid artery injury is the cavernous segment, which may result in fistulous connection to the cavernous sinus and ophthalmic veins, which in turn lead to pressure symptoms in the ipsilateral orbit. Unlike the commonly reported direct traumatic carotid-cavernous fistula, we describe an unusual case of a 38-year-old man presented with a traumatic brain injury led to a fistula connection between the cavernous carotid artery and the ipsilateral basal vein of Rosenthal, with eventual drainage to the straight and transverse sinuses. The basal vein of Rosenthal is usually formed from confluence of anterior and middle cerebral veins deep in the Sylvian fissure and drain the insular cortex and the cerebral peduncles to the vein of Galen. Immediate endovascular deployment of a covered stent in the cavernous carotid artery allowed sealing the laceration site. Three months follow up showed a non-focal neurological examination and healed carotid laceration over the covered stent.

Treatment of cerebral aneurysms in children: analysis of the Kids' Inpatient Database

OBJECT.: Endovascular coiling and surgical clipping are viable treatment options of cerebral aneurysms. Outcome data of these treatments in children are limited. The objective of this study was to determine hospital mortality and complication rates associated with surgical clipping and coil embolization of cerebral aneurysms in children, and to evaluate the trend of hospitals' use of these treatments.

METHODS

The authors identified a cohort of children admitted with the diagnoses of cerebral aneurysms and aneurysmal subarachnoid hemorrhage from the Kids' Inpatient Database for the years 1998 through 2009. Hospital-associated complications and in-hospital mortality were compared between the treatment groups and stratified by aneurysmal rupture status. A multivariate regression analysis was used to identify independent variables associated with in-hospital mortality. The Cochrane-Armitage test was used to assess the trend of hospital use of these operations.

RESULTS

A total of 1120 children were included in this analysis; 200 (18%) underwent aneurysmal clipping and 920 (82%) underwent endovascular coiling. Overall in-hospital mortality was higher in the surgical clipping group compared with the coil embolization group (6.09% vs 1.65%, respectively; adjusted odds ratio [OR] 2.52, 95% CI 0.97-6.53, p = 0.05). The risk of postoperative stroke or hemorrhage was similar between the two treatment groups (p = 0.86). Pulmonary complications and systemic infection were higher in the surgical clipping population (p < 0.05). The rate of US hospitals' use of endovascular coiling has significantly increased over the years included in this study (p < 0.0001). Teaching hospitals were associated with a lower risk of death (OR 0.13, 95% CI 0.03-0.46; p = 0.001).

CONCLUSIONS

Although both treatments are valid, endovascular coiling was associated with fewer deaths and shorter hospital stays than clip placement. The trend of hospitals' use of coiling operations has increased in recent years.

How Safe is Eptifibatide during Urgent Carotid Artery Stenting?

Background: Glycoprotein IIB/IIIA inhibitors are occasionally utilized during carotid artery stenting (CAS) in the presence or absence of a visualized intra-operative thrombus.

Objective: We assess the hemorrhagic and clinical outcomes associated with the use of eptifibatide during CAS.

Methods: A retrospective analysis of prospectively collected data on patients with the diagnosis of carotid artery stenosis underwent CAS in a single center. We identified those who received intravenous eptifibatide intra-operatively and compared to the rest of the cohort. Hemorrhagic outcomes included intracerebral hemorrhage (ICH) or groin hematoma that occurred during the hospital stay.

Results: In this analysis, 81 patients had CAS during a 3-year span; 16 of those had received 15 mg of intravenous eptifibatide intra-operatively. The mean age of the treated and untreated patients was similar (65.6 ± 13.4 versus 65.4 ± 10.2; P = 0.13). One patient (1.2%) in this series had ICH in the perioperative period that occurred in the non-eptifibatide group. Five patients (6.2%) in this series had groin hematoma; only one in the non-eptifibatide group required surgical repair. No mortality was reported and clinical outcomes including discharge modified Rankin scale, NIH stroke scale, as well as discharge destination were similar in both groups. A stratified analysis among those who underwent an urgent CAS showed no significant differences in the risks of hemorrhages or any clinical outcome (P > 0.05).

Conclusion: The use of eptifibatide during CAS is safe. The risk of any hemorrhagic complication is rare in this series; however, a prospective study to validate this observation will be helpful.

Abstract WP239: Stroke Mimics Treated with Thrombolysis: A Single Center Experience

Background: Recent reports suggested better outcomes associated with the drip-and-ship paradigm for acute ischemic stroke (AIS) treated with thrombolysis. Alternative hypothesis is a higher rate of stroke mimics (SM) among AIS treated in a non-specialized stroke centers and then transferred to comprehensive centers.

Methods: Consecutive patients treated with thrombolysis according to the admission criteria were reviewed in a single comprehensive stroke center over one academic year. Information on the basic demographic, hospital complications, psychiatric diagnoses, and discharge information were collected. We also identified those who were treated in outside facility and then transferred to the tertiary center (i.e. drip-and-ship paradigm). Comparative and adjusted analysis to identify predictors for stroke mimics was performed.

Results: 120 patients were treated with thrombolysis for AIS included in this analysis; 20 (16.7%) were discharged with the final diagnosis of SM; 14 of those had conversion syndrome and 6 patients had other syndromes (seizures, migraine, and hypoglycemia). Patients with SM were younger (55.6 ± 15.0 versus 69.4 ± 14.9, P = 0.0003), had a slight female preponderance (55% versus 46%; P = 0.46); and more likely to harbor a psychiatric diagnosis (45% versus 9%; P = <0.0001). Eighteen of 20 SM patients (90%) had the drip-and-ship treatment paradigm compared to 65% of those with AIS (P= 0.02). None of SM had any hemorrhagic complications and all were discharged to home. Predictors of SM on adjusted analysis included the drip-and-ship paradigm (OR 12.8, 95% CI 1.78, 92.1) and history of any psychiatric illness (OR 12.08; 95% CI 3.14, 46.4).

Conclusion: Drip-and-ship paradigm and the presence of any psychiatric history predict the diagnosis of SM. None of the SM had any thrombolysis related complication and all were discharged to home. These findings may explain the superior outcomes associated with the drip-and-ship paradigm in the treatment of AIS

A Population Based Study on Mishaps During Laparoscopic Cholecystectomy in Qatar: 10 Years Experience

In order to determine the national incidence of adverse events following laparoscopic cholecystectomy (LC) the records were reviewed retrospectively of4861 patients who underwent LC over a period often years (1993-2003).

The most serious non-biliary complication was trocar injury of major vessels in three cases. Other non-biliary complications included duodenal perforation during dis-section of the Calot's triangle, small bowel injury while inserting the umbilical port and trocar site hernia. Adverse biliary events included common bile duct injury, common hepatic duct injury, bile leakage from the cystic duct and one instance of the migration of an endoloop into the com-mon bile duct. Conversion to open cholecystectomy was required in 109 cases.

Although LC may be associated with various adverse sequelae, these are rare and should not deter surgeons and patients.

Oral anticoagulation therapy during pregnancy in patients with mechanical mitral valves: a prospective study

Reports on phenindione toxicity have limited its use as an oral anticoagulant. Our aim was to evaluate its risks in pregnant women. Thirty-one pregnancies in 29 women with mitral (+/-aortic) St. Jude mechanical valves were followed-up prospectively. Eighteen patients received phenindione. Eleven patients (37.9%) received in addition to phenindione 225 mg dipyridamole, which was given in three doses. The target INR was 2.5-3.5 in the former and 2-2.5 in the latter treatment. A fortnight before delivery, intravenous heparinotherapy was substituted. There were no maternal complications, apart from a single postpartum hemorrhage (3.2%). After the deliveries the results were: 26 mature babies (83.9%), 3 premature babies (9.7%) and 2 cases of stillbirth (6.4%). Outcome was dose related; being 57.2+/-20.9 mg/day for mature babies and 82.5+/-11.2 mg/day for prematures and stillbirths (P=0.016). Phenindione provided safe and effective anticoagulation during pregnancy. A larger study is necessary to confirm the relationship between the dosage and outcome.

Standard versus low-level anticoagulation combined to low-dose dipyridamole after mitral valve replacement

BACKGROUND

Although the addition of 300 mg dipyridamole to oral anticoagulants has been shown to decrease thromboembolic events after cardiac valve replacement, reports of combined therapy were few and some showed significant dipyridamole-related side effects and intolerance. The aim of this study was to compare the clinical effect of a standard monotherapy (targeting an international normalized ratio - INR - between 2.5 and 3.5) to a less intensive regimen (targeting an INR between 2 and 2.5) combined to a small dose of dipyridamole (225 mg/day).

METHODS

Between January 1990 and December 1998, 486 young rheumatic patients with a St Jude mitral valve prosthesis were assigned to follow either standard monotherapy (294 patients) or low-level combined therapy (192 patients). Phenindione has been the anticoagulant of choice. Up to a maximum daily dose of 100mg, patients failing to achieve their target INR range were shifted to warfarin therapy. Prothrombin time was checked monthly and asymptomatic patients with a too low or a too high INR (<1.3 or >5) were briefly hospitalized for INR control. Complete blood picture, renal and hepatic profiles and full echocardiographic study were done biannually.

RESULTS

With the exception of a significantly larger left atrium in patients on low-level combined therapy (P=0.001), both groups were comparable as regards to age and sex distribution, number of patients with atrial fibrillation, left atrial thrombus and history of stroke. Patients were monitored for 1712.6 pt yr and follow-up was 96.7% complete. No phenindione-related complications were observed (mean dose 62.3+/-21.4 mg), 20 patients (4.1%) had failed to achieve their target INR range and were switched to warfarin and only three patients (1.6%) had tolerable dipyridamole-related side effects. Compared to standard monotherapy, patients on low-level combined therapy showed significantly lower annualized rates: thromboembolism (1.6 vs 0.43%: risk reduction 71%; P=0.05), thromboembolism and hemorrhage (2.7 vs 0.7%: risk reduction 72%; P=0.005), death due to valve thrombosis or stroke (1.17 vs 0. 14%: risk reduction 81%; P=0.04) as well as both non-fatal (3.3 vs 1. 57%: risk reduction 51%; P=0.04) and total late postoperative complications (5.35 vs 3.14%: risk reduction 40%; P=0.04); respectively. However, total late mortality (32 patients; 1.8% per pt yr) was comparable among both groups.

CONCLUSION

Low-level anticoagulation with phenindione combined to low dosage of dipyridamole was clinically more effective than the higher standard monotherapy. With respect to the prescribed doses, both drugs were well tolerated by almost all patients. Use of dipyridamole did not influence overall patients' survival.

Laser stapedotomy

Thirty-four ears with conductive hearing loss due to otosclerosis were operated upon using the laser stapedotomy technique. Audiological results were compared with the results of 316 non-laser stapedotomies. The post-operative air-bone gap, calculated as the difference between the post-operative air and bone conduction levels, was smaller with the laser stapedotomy group. Also, the bone conduction showed significant improvement with the use of laser. Significant sensorineural hearing loss was not found in any of the laser-treated patients. According to our results, we concluded that laser is of benefit in stapes surgery for improving the hearing results and minimizing the inner ear trauma.