Prioritizing Radiation and Targeted Systemic Therapy in Patients with Resected Brain Metastases from Lung Cancer Primaries with Targetable Mutations: A Report from a Multi-Site Single Institution

PURPOSE/OBJECTIVE(S)

Brain metastases (BrM) are a common complication of non-small cell lung cancer (NSCLC), present in up to 50% of patients. While treatment of BrM requires a multidisciplinary approach with surgery, radiotherapy (RT), and systemic therapy, advances in sequencing have improved outcomes with targetable alterations in PDL-1, EGFR, ALK, and KRAS mutations. With a push towards molecular characterization of cancers, we sought out to examine outcomes by treatment modalities at our institution with respect to prioritizing RT and targeted therapies.

MATERIALS/METHODS

After IRB approval, we identified patients treated with a surgical resection of BrM from NSCL primaries between 2011 to 2022 at 5 sites at our institution. Tumor molecular profiles were reviewed and patients with PDL-1, EGFR, ALK, and KRAS mutations were evaluated by a treatment modality: surgery alone or in combination with RT (SRS, WBRT) and/or systemic therapy (TKIs -1st-3rd generations, immunotherapy). The primary endpoints were in-brain freedom from progression (FFP) and overall survival (OS). SAS Studio version 4.4 was used to perform statistical analyses.

RESULTS

We identified 272 patients with 162/272 (60%) patients with adequate follow-up included in this analysis. The median follow-up was 27.8 months (range, 0.43 - 134.45 months). There were 59.2% females and 40.7% males, with median ages at diagnosis of 67 years for females and 66 for males, respectively. Of the entire cohort, 102/162 (63%) patients received adjuvant combination RT and systemic therapy, and 60/162 (37%) received adjuvant monotherapy (p <0.0001). The use of systemic therapy was associated with 9.89 months median time to progression vs 4.87 months without it (p = 0.077), respectively. Similarly, patients treated with a combination of RT and systemic therapy had a median FFP time of 9.77 months vs 5.28 months (p = 0.064). No significant difference in OS was found with or without systemic therapy.

CONCLUSION

After resection of BrM from NSCLC with PDL-1, EGFR, ALK, and KRAS mutations, we found that systemic therapy, including TKIs and immunotherapy, may have an increasing role in delaying time to progression. At our institution, as we continue to identify actionable mutations, a statistically significant number of patients continue to be treated with a combination of RT and systemic therapies with a trend toward superior FFP.

Palmitoylation of the Alternative Amino Terminus of the BTK-C Isoform Controls Subcellular Distribution and Signaling

BACKGROUND

The alternative transcriptional isoform of Bruton's tyrosine kinase, BTK-C, is expressed in a wide variety of epithelial tumor types where it impacts apoptosis resistance, therapeutic escape, and glucose uptake. The initial exon in BTK-C encodes a 34 amino acid extension of the amino terminus of the canonical BTK-A isoform. Its function is unknown.

MATERIALS AND METHODS

Site-directed mutagenesis, acylation assays and expression studies in cancer cell lines were used to determine the effects that the BTK-C first exon sequence has on kinase activity, subcellular localization and cell physiology. Analysis of BTK-C expression in tumors was conducted using genomic databases.

RESULTS

BTK-C is palmitoylated on two cysteine residues. BTK-C localization at the plasma membrane is dependent upon phosphatidylinositol 3,4,5-triphosphate (PIP₃) levels as well as palmitoylation. In epithelial cancer cells, both BTK-A and BTK-C isoforms are recruited to the plasma membrane; however, BTK-A also localizes to the nucleus whereas BTK-C has a primarily perinuclear distribution. Transcription of the BTK-C isoform is inversely correlated with expression of commonly activated breast cancer signaling receptors in breast tumors. In MDA-MB-231 cells, BTK-C expression confers modest increases in proliferation and glucose uptake rates compared to BTK-A.

CONCLUSION

Palmitoylation affects localization and regulation of BTK-C in epithelial tumor cells where it functions as an important survival factor. Expression of either palmitoylated or non-palmitoylated kinase isoforms that function in PI3K signaling may be a common regulatory feature as nine other soluble kinases in the human genome possess similarly encoded alternative N-termini (ANT).

Abstract 3: Developing a translational tool for GLP-1-based therapeutic agonists in humanized GLP1R mice

Glucagon-like peptide-1 (GLP1) is a pleiotropic hormone released from gut enteroendocrine cells following nutrient ingestion. In addition to promoting insulin secretion and inhibiting glucagon secretion, GLP1 acts via the glucagon-like peptide-1 receptor (GLP1R) to reduce gastric emptying and food intake. Therefore, development of GLP1R agonists appears to be a promising therapeutic option for type 2 diabetes. To evaluate the efficacy of GLP1 analogs in preclinical studies, Biocytogen has successfully generated a novel humanized GLP1R (B-hGLP1R) knock-in mouse line to support related drug development studies. In this mouse model, the full coding sequence of the human GLP1R gene was inserted into the mouse Glp1r gene locus. Human GLP1R mRNA expression was detected by RT-PCR in B-hGLP1R mice but not in wild-type mice. Protein expression of human GLP1R in B-hGLP1R mice was confirmed by western blot analysis and immunohistochemistry using pancreatic tissues. Furthermore, flow cytometry analysis of leukocyte subpopulations showed that B-hGLP1R mice do not exhibit a change in the overall development, differentiation, or distribution of immune cell types in the spleen, blood, and lymph nodes. Additionally, our in vivo efficacy study confirmed Dulaglutide, a GLP1 receptor agonist, reduced the non-fasting blood glucose, fasting blood glucose, glucagon, and food intake levels in B-hGLP1R obese mice and increased plasma insulin and GLP1 secretion. In B-hGLP1R mice, glucose tolerance (GTT) was also improved by Dulaglutide treatment, similar GTT results were observed after treatment with PF-06882961, a phase II agent specifically recognizing human GLP1R. Altogether, B-hGLP1R mice provide an efficacious preclinical animal model to evaluate novel GLP1 based therapeutic drugs. Keywords: Humanized mice, GLP1R, agonist

Citation Format: Yuelei Shen, Jiawei Yao, Mostafa Kokabee, Yanan Guo, Yang BaI, Chengzhang Shang. Developing a translational tool for GLP-1-based therapeutic agonists in humanized GLP1R mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3.

Bruton's Tyrosine Kinase and Its Isoforms in Cancer

Bruton’s tyrosine kinase (BTK) is a soluble tyrosine kinase with central roles in the development, maturation, and signaling of B cells. BTK has been found to regulate cell proliferation, survival, and migration in various B-cell malignancies. Targeting BTK with recently developed BTK inhibitors has been approved by the Food and Drug Administration (FDA) for the treatment of several hematological malignancies and has transformed the treatment of several B-cell malignancies. The roles that BTK plays in B cells have been appreciated for some time. Recent studies have established that BTK is expressed and plays pro-tumorigenic roles in several epithelial cancers. In this review, we focus on novel isoforms of the BTK protein expressed in epithelial cancers. We review recent work on the expression, function, and signaling of these isoforms and their value as potential therapeutic targets in epithelial tumors.

The first cohort of Iranian patients with hyper immunoglobulin E syndrome: A long-term follow-up and genetic analysis

BACKGROUND

Hyper-IgE syndromes (HIES) are distinct diseases characterized by recurrent cutaneous and lung infections, eczema, and elevated serum IgE level.

METHODS

In this study, clinical manifestations, immunologic findings, and genetic studies of all patients with HIES in the Iranian national registry database were evaluated.

RESULTS

A total of 129 HIES patients with a median age of 14.0 (9.0-24.0) years were followed up for a total of 307.8 patient-years. Genetic studies showed heterozygous STAT3 mutations in 19 patients and homozygous DOCK8 mutation in 16 patients. The mean of National Institutes of Health score in STAT3-deficient patients was higher than in patients with DOCK8 mutation (P = 0.001). It was shown that the presence of pneumatocele and hematologic complication were significantly frequent in STAT3-deficient cases compared to patients with DOCK8 deficiency (P = 0.001 and P = 0.002, respectively). Moreover, the median IgE serum levels were higher in patients with STAT3 gene mutation than in patients with DOCK8 gene mutation (P = 0.02). The eosinophils' count was enhanced in patients with DOCK8 deficiency than in patients with STAT3 gene defects (P = 0.02).

CONCLUSION

Specific molecular study of STAT3 and DOCK8 mutations in patients with HIES clinical phenotype could help the physician to definitively characterize the disease. Since HIES showed the highest rate of unsolved combined immunodeficiency, investigation of other genetic and environmental factors could also help in understanding the mechanism of remaining patients as well as providing strategy into therapeutic modalities.

Global metabolite profiling analysis of lipotoxicity in HER2/neu-positive breast cancer cells

Recent work has shown that HER2/neu-positive breast cancer cells rely on a unique Warburg-like metabolism for survival and aggressive behavior. These cells are dependent on fatty acid (FA) synthesis, show markedly increased levels of stored fats and disruption of the synthetic process results in apoptosis. In this study, we used global metabolite profiling and a multi-omics network analysis approach to model the metabolic changes in this physiology under palmitate-supplemented growth conditions to gain insights into the molecular mechanism and its relevance to disease prevention and treatment. Computational analyses were used to define pathway enrichment based on the dataset of significantly altered metabolites and to integrate metabolomics and transcriptomics data in a multi-omics network analysis. Network-predicted changes and functional relationships were tested with cell assays in vitro. Palmitate-supplemented growth conditions induce distinct metabolic alterations. Growth of HER2-normal MCF7 cells is unaffected under these conditions whereas HER2/neu-positive cells display unchanged neutral lipid content, AMPK activation, inhibition of fatty acid synthesis and significantly altered glutamine, glucose and serine/glycine metabolism. The predominant upregulated lipid species is the novel bioactive lipid N-palmitoylglycine, which is non-toxic to these cells. Limiting the availability of glutamine significantly ameliorates the lipotoxic effects of palmitate, reduces CHOP and XBP1(s) induction and restores the expression levels of HER2 and HER3. The study shows that HER2/neu-positive breast cancer cells change their metabolic phenotype in the presence of palmitate. Palmitate induces AMPK activation and inhibition of fatty acid synthesis that feeds back into glycolysis as well as anaplerotic glutamine metabolism.