P10.10.A Tumor Treating Fields (TTFields), temozolomide and lomustine co-application is efficacious in glioblastoma cancer cell lines

Background

Temozolomide (TMZ) is the standard of care chemotherapy for newly diagnosed glioblastoma (ndGBM), the most common primary malignant brain tumor in adults. However, 50% of patients do not respond to TMZ due to expression of O6-methylguanine-DNA methyltransferase (MGMT), the enzyme involved in repair of TMZ-induced damage. Tumor Treating Fields (TTFields) are alternating electric fields that display anti-mitotic effects on cancerous cells, and have been shown to induce a state of BRCAness in various cancer types. Concurrent treatment with TMZ and TTFields demonstrated a major advance in treatment of patients with ndGBM, and was approved by the FDA in 2014. Recently, the addition of lomustine (CCNU) to TMZ demonstrated clinical benefit in ndGBM patients, with improved overall and progression free survival. The aim of the current study was to examine in GBM cells the effect of TTFields in conjunction with TMZ and CCNU.

Materials and Methods

U-87 MG, LN229, U118 and LN18 human GBM cell lines were tested for their MGMT expression levels, and treated with TTFields (200 kHz, of 0.83 V/cm RMS) for 72 h using the inovitro system. Efficacy of concomitant application of TTFields with TMZ and/or CCNU was tested by measuring cell count, colony formation, and apoptosis levels.

Results

U-87 MG and LN229 displayed no expression of MGMT, while U118 and LN18 expressed low and high levels of MGMT, respectively. Application of TMZ and TTFields resulted in increased cytotoxicity compared with each treatment alone, with an additive interaction seen in all examined cell lines. The cytotoxic effect resulting from co-application of CCNU with TTFields suggested a synergistic interaction between the two modalities for U-87 MG, LN229, and U118, an additivity for LN18. Concurrent TTFields/TMZ/CCNU was more efficacious than TTFields or TMZ/CCNU separately in all cell lines.

Conclusions

Application of TTFields with TMZ was additive, irrespective of MGMT expression levels, while TTFields with CCNU was additive when MGMT was plentiful, but displayed tendency to synergism when MGMT was absent or limited. These outcomes are in line with the BRCAness state induced by TTFields, as in the absence of MGMT, DNA damage induced by CCNU requires the BRCA pathway for repair. Application of TTFields together with TMZ and CCNU demonstrated increased efficacy, suggesting potential benefit of such therapy for ndGBM treatment.

Investigating the role of allergic contact dermatitis in residual ocular surface disease on dupilumab (ROSDD),

Background

The mechanisms underlying eye-related complications with dupilumab are poorly understood.

Objective

This study aimed to determine the incidence and characteristics of ocular complications with dupilumab and the prevalence of comorbid allergic contact dermatitis in the same subpopulation.

Methods

This is a retrospective chart review of 48 patients with atopic dermatitis who received dupilumab. For patients with eye involvement at first follow-up, we discuss the presence of eyelid dermatitis, blepharitis, or conjunctivitis and analyze available patch test findings in patients with ocular complications while treated with dupilumab.

Results

A total of 14 patients (29.2%) showed eye involvement while on dupilumab, all of whom experienced eye involvement prior to dupilumab. The results of the patch test were most commonly positive for emulsifier/surfactants (42.5%) and fragrances (30.4%). Nine patients experienced improvement with allergen avoidance subsequent to patch testing, and four of nine patients’ conditions cleared almost entirely. This is a non-randomized study in a small cohort of patients. Only 18 patients had their disease confirmed by an ophthalmologist.

Conclusion

All patients with eye involvement while on dupilumab had a history of eye involvement prior to dupilumab, suggest that dupilumab may encourage rather than cause ocular surface inflammation. Significant improvement after patch testing in nearly half of patients suggests that allergic contact dermatitis contributes to some cases of dupilumab-associated eye complications.

Migration of retinal cells through a perforated membrane: implications for a high-resolution prosthesis

PURPOSE

One of the critical difficulties in design of a high-resolution retinal implant is the proximity of stimulating electrodes to the target cells. This is a report of a phenomenon of retinal cellular migration into a perforated membrane that may help to address this problem.

METHODS

Mylar membranes with an array of perforations (3-40 microm in diameter) were used as a substrate for in vitro retinal culture (chicken, rats) and were also transplanted into the subretinal space of adult RCS rats. A membrane was also constructed with a seal on one side to restrict the migration.

RESULTS

Retinal tissue in vitro grew within 3 days through perforations of greater than 5 microm in diameter when the membranes were positioned on the photoreceptor side, but no migration occurred if the implant was placed on the inner retinal surface. Histology with light microscopy and transmission electron microscopy (TEM) demonstrated that migrating cells retain neuronal structures for signal transduction. Similar growth of RCS rat retinal cells occurred in vivo within 5 days of implantation. A basal seal kept the migrating tissue within a small membrane compartment.

CONCLUSIONS

Retinal neurons migrate within a few days into perforations (> 5 microm in diameter) of a membrane placed into the subretinal space. This may provide a means of gaining close proximity between electrodes in a retinal prosthetic chip and target cells, and thus allow a greater density of stimulating elements to subserve higher resolution. Further studies are needed to explore the long-term stability of the retinal migration.

A comparison of consumer and provider preferences for research on homeless veterans

Despite the dramatic growth of homelessness research, there have been no systematic assessments of consumer and provider preferences regarding the content of this research. Therefore, 87 clients and 28 staff of a homeless veterans program were administered a 15-item questionnaire requesting identification of the 5 "most" and 5 "least" important research topics. Staff and clients differed significantly on 6 items considered most important and 4 items considered least important. Clients wanted more research that focused on material needs, whereas staff preferences were more broadly distributed. The fact that appreciable data exist for many of the research topics that respondents identified as important raises concerns about the accessibility of homelessness research.

Primary Pseudomonas pneumonia in a previously healthy man

A 29-year-old previously healthy man had a Pseudomonas aeruginosa pneumonia and bacteremia. Early recognition of the organism and institution of appropriate antibiotic therapy led to rapid clinical response and recovery. Although Pseudomonas is rarely the cause of pneumonia in a healthy host, it should be considered in the differential diagnosis.