The nutritional supplement taurine activates p53-dependent and independent tumor suppressor mechanisms in various cellular models of ovarian cancer

Loss of treatment-induced ovarian carcinoma (OC) growth suppression poses a major clinical challenge because it leads to disease recurrence. Therefore, there is a compelling need for well- -tolerated approaches that can support tumor growth-suppression after therapy is stopped. We have profiled ascites as OC tumor microenvironments to search for potential non-toxic soluble components that would activate tumor suppressor pathways in OC cells. Our investigations revealed that low levels of taurine, a non-proteogenic sulfonic amino acid, were present within OC ascites. Taurine supplementation, beyond levels found in ascites, induced growth suppression without causing cytotoxicity in various OC cells, including chemotherapy-resistant cell clones and patient-derived organoids representing primary or chemotherapy recovered disease. Inhibition of proliferation by taurine was linked to increased mutant or wild-type p53 proteins binding to DNA, induction of p21, and independently of p53, TIGAR expression. Taurine-induced activation of p21 and TIGAR was associated with suppression of cell-cycle progression, glycolysis, and mitochondrial respiration. Expression of p21 or TIGAR in OC cells mimicked taurine-induced growth suppression. Our studies support the potential therapeutic value of taurine supplementation in OC.

Extracellular Matrix Modulates Outgrowth Dynamics in Ovarian Cancer

Ovarian carcinoma (OC) forms outgrowths that extend from the outer surface of an afflicted organ into the peritoneum. OC outgrowth formation is poorly understood due to the limited availability of cell culture models examining the behavior of cells that form outgrowths. Prompted by immunochemical evaluation of extracellular matrix (ECM) components in human tissues, laminin and collagen-rich ECM-reconstituted cell culture models amenable to studies of cell clusters that can form outgrowths are developed. It is demonstrated that ECM promotes outgrowth formation in fallopian tube non-ciliated epithelial cells (FNE) expressing mutant p53 and various OC cell lines. Outgrowths are initiated by cells that underwent outward translocation and retained the ability to intercalate into mesothelial cell monolayers. Electron microscopy, optical coherence tomography, and small amplitude oscillatory shear experiments reveal that increased ECM levels led to increased fibrous network thickness and high shear elasticity of the microenvironment. These physical characteristics are associated with outgrowth suppression. The low ECM microenvironment mimicks the viscoelasticity of malignant peritoneal fluid (ascites) and supports cell proliferation, cell translocation, and outgrowth formation. These results highlight the importance of the ECM microenvironment in modulating OC growth and can provide additional insights into the mode of dissemination of primary and recurrent ovarian tumors.

Abstract B11: Collective extrusion initiates dissemination in organotypic model of high-grade serous carcinoma

Development of serous tubal intraepithelial carcinoma (STIC) from transformed fallopian tube secretory epithelial cells (FTSEC) is considered to be an initiating event for a significant proportion of high-grade serous carcinomas (HGSCs). Some regions of STIC lesions can form multicellular loosely cohesive outgrowths that apically extend out of the tubal epithelium. These outgrowths can detach and disseminate within the peritoneal cavity, causing organ obstruction. Immunohistochemical analysis of STICs suggests the possibility that molecular pathways associated with proliferation, DNA repair, cytoskeletal dynamics, and extracellular matrix adhesion contribute to outgrowth formation. Due to limited availability of transformed FTSEC in vitro culture models that faithfully capture outgrowth dynamics, the role of these pathways in STIC/HGSC outgrowth formation remains unknown. Here we present the development of an organotypic model of outgrowth formation. Long-term live-cell imaging of transformed human, and mouse FTSEC and STIC-like multicellular organotypic assemblies, have shown that outgrowths are initiated by collective apical extrusion of less-cohesive, loosely attached cell populations that can proliferate outside of the organotypic assembly. mRNA and immunofluorescence analysis of loosely attached cell populations revealed: (i) activation of Rho pathway, (ii) increased expression of several alpha integrin subunits that form heterodimers with beta 1 integrin, and (iii) nonpolarized apical and junctional localization of activated integrin beta 1. Pharmacologic or genetic inhibition of Rho-associated kinase (ROCK) blocked outgrowth formation without affecting cell proliferation. Conversely, activation of Rho significantly accelerated outgrowths, indicating that Rho-ROCK is a critical regulator of early steps of HGSC dissemination. Quantitative image-based evaluation of ROCK target phosphorylated myosin light chain expression in patient-derived xenograft cells revealed the presence of cell populations with high ROCK activation. Blocking integrin beta 1 activity resulted in the disintegration of already formed outgrowths. Our data indicate that cell populations with high Rho/ROCK activity remodel integrin beta 1-dependent adhesion to initiate apical extrusion and peritoneal dissemination.

Citation Format: Sarah Alshehri, Sadaf Farsinejad, Douglas Kung, Estefan Santi, Yali Zhai, Thomas Cattabiani, Hongjun Wang, Kathleen Cho, Marcin Iwanicki. Collective extrusion initiates dissemination in organotypic model of high-grade serous carcinoma [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B11.

Endovascular treatment for acute basilar thrombosis via a transradial approach: Initial experience and future considerations

Acute basilar artery occlusion (BAO) secondary to emergent large vessel occlusion (ELVO) has an extremely poor natural history, with a reported mortality rate up to 95%. Mechanical thrombectomy in the setting of ELVO is generally performed via a transfemoral approach. However, radial access is increasingly being utilized as an alternative. We report our initial multi-institutional experience using primary radial access in the treatment of acute BAO in nine consecutive cases. Technical success defined as a TICI score of 2B or 3 was achieved in 89% of cases. Average puncture to revascularization time was 35.8 minutes. There were no complications related to radial artery catheterization. We contend radial access should potentially be considered as the first-line approach given inherent advantages over femoral access for mechanical thrombectomy for BAO.

A single pipeline embolization device is sufficient for treatment of intracranial aneurysms

BACKGROUND AND PURPOSE

The Pipeline Embolization Device has emerged as an important treatment option for intracranial aneurysms. The number of devices needed to treat an aneurysm is uncertain and is the subject of vigorous debate. The purpose of this study was to compare rates of complications, aneurysm occlusion, and outcome in patients treated with a single-versus-multiple Pipeline Embolization Devices.

MATERIAL AND METHODS

One hundred seventy-eight patients were treated with the Pipeline Embolization Device at our institution. Patients were divided into 2 groups: a single-device group (n = 126) and a multiple-device group (n = 52).

RESULTS

There was no statistically significant difference between the 2 groups with respect to baseline characteristics except for age and aneurysm size (higher with multiple Pipeline Embolization Devices). Complications occurred more frequently with multiple (15%) versus a single device (5%, P = .03). In multivariate analysis, the use of multiple devices independently predicted complications. A similar proportion of patients achieved adequate aneurysm obliteration at follow-up in the single-device (84%) and the multiple-device groups (87%, P = .8). In multivariate analysis, age and follow-up time predicted obliteration. At follow-up, a significantly higher proportion of patients treated with a single device (97%) achieved a favorable outcome compared with those treated with multiple devices (89%, P = .03). In multivariate analysis, there was a strong trend for the use of a single device to predict favorable outcomes (P = .06).

CONCLUSIONS

Treatment with a single Pipeline Embolization Device provides similar occlusion rates with less complications and better overall outcomes. These findings suggest that a single Pipeline Embolization Device is sufficient for treatment of most intracranial aneurysms.

Fos expression in rat celiac ganglion: an index of the activation of postganglionic sympathetic nerves

To develop an index of the activation of abdominal sympathetic nerves, we used Fos immunostaining of the celiac ganglion (CG) taken from rats receiving nicotine, preganglionic nerve stimulation, or glucopenic agents. Subcutaneous nicotine injection moderately increased Fos expression in the principal ganglionic cells of the CG (17 +/- 4 Fos+ per mm(2), approximately 12% of all principal CG cells), whereas subcutaneous saline had no effect (0 +/- 0 Fos+ per mm(2); n = 7; P < 0.01). Greater Fos expression was obtained by applying nicotine topically to the CG (71 +/- 8 Fos+ per mm(2); 52% of all principal CG cells, n = 5; P < 0.01 vs. topical saline, n = 4) and by preganglionic nerve stimulation (126 +/- 9 Fos+ per mm(2); 94% of all principal CG cells, n = 11; P < 0.01 vs. nerve isolation, n = 7). Moderate Fos expression was also observed in the CG after intraperitoneal 2-deoxy-D-glucose (2DG) injection (21 +/- 2 Fos+ per mm(2); 16% of all principal CG cells, n = 5; P < 0.01 vs. saline ip) or insulin injection (16 +/- 2 Fos+ per mm(2); 12% of all principal CG cells, n = 6; P < 0.01 vs. saline ip). Furthermore, Fos expression induced by 2DG was dose and time dependent. These data demonstrate significant Fos expression in the CG in response to chemical, electrical, and reflexive stimulation. Thus Fos expression in the CG may be a useful index to describe various levels of activation of its postganglionic sympathetic neurons.

Direct administration of methotrexate into the central nervous system of primates. Part 1: Distribution and degradation of methotrexate in nervous and systemic tissue after intraventricular injection

Levels of methotrexate (MTX) measured by both 3H radioactivity and dihydrofolate reductase assays were determined in cerebrospinal fluid (CSF), plasma, urine, and both neural and non-neural tissues at varying times after a single intraventricular injection into Cynomolgus monkeys (Macaca fascicularis). Clearance of the MTX from CSF was rapid after injection. A relatively constant level of 3HMTX was reached in plasma 2 1/2 hours after injection, and about 30% of the 3HMTX dose was excreted in the urine within 4 hours after injection. Maximum levels in CNS tissues were obtained by 4 hours after injection, and average concentrations of 10(-6) M MTX (moles/kg wet weight) were maintained in CSF for up to 12 hours and in brain for up to 24 hours after injection. Conversion of MTX to non-MTX products was detected in CSF between 4 and 12 hours, and in brain tissue between 12 and 24 hours after injection, and the amount of these products increased with time. Regional distribution studies in the cerebrum showed a U-shaped distribution curve for 3HMTX up to 12 hours after injection, which closely followed the 14C inulin distribution. Thus, the levels in deep cerebral tissue were less than the average level for brain, and this suggests that treatment of CNS tumors by intraventricular injection may have variable results, partly due to complex tissue distribution patterns.