Maternally Contributed Folate Receptor 1 Is Expressed in Ovarian Follicles and Contributes to Preimplantation Development

Folates have been shown to play a crucial role for proper development of the embryo as folate deficiency has been associated with reduced developmental capacity such as increased risk of fetal neural tube defects and spontanous abortion. Transcripts encoding the reduced folate carrier RFC1 (SLC19A1 protein) and the high-affinity folate receptor FOLR1 are expressed in oocytes and preimplantation embryos, respectively. In this study, we observed maternally contributed FOLR1 protein during mouse and human ovarian follicle development, and 2-cell mouse embryos. In mice, FOLR1 was highly enriched in oocytes from primary, secondary and tertiary follicles, and in the surrounding granulosa cells. Interestingly, during human follicle development, we noted a high and specific presence of FOLR1 in oocytes from primary and intermediate follicles, but not in the granulosa cells. The distribution of FOLR1 in follicles was noted as membrane-enriched but also seen in the cytoplasm in oocytes and granulosa cells. In 2-cell embryos, FOLR1-eGFP fusion protein was detected as cytoplasmic and membrane-associated dense structures, resembling the distribution pattern observed in ovarian follicle development. Knock-down of Folr1 mRNA function was accomplished by microinjection of short interference (si)RNA targeting Folr1, into mouse pronuclear zygotes. This revealed a reduced capacity of Folr1 siRNA-treated embryos to develop to blastocyst compared to the siRNA-scrambled control group, indicating that maternally contributed protein and zygotic transcripts sustain embryonic development combined. In summary, maternally contributed FOLR1 protein appears to maintain ovarian functions, and contribute to preimplantation development combined with embryonically synthesized FOLR1

Effect of nephrectomy and captopril on autoregulation of cerebral blood flow in rats

The present study investigated the effect of circulating versus locally present renin on cerebral blood flow (CBF) and its autoregulation in rats. CBF was measured repetitively with the intracarotid 133Xe injection method, whereas blood pressure was lowered to determine the lower limit of autoregulation. To remove renin from the blood, rats were bilaterally nephrectomized and kept alive with peritoneal dialysis for 48 h. Five groups of animals were studied: 1) nephrectomized dialyzed rats, 2) nephrectomized dialyzed rats given a single intravenous dose of the angiotensin-converting enzyme inhibitor captopril (10 mg/kg), 3) sham nephrectomized and dialyzed rats, 4) rats receiving drugs as dialyzed rats but no surgery, and 5) rats given the same diet as the other groups but no drugs and no surgery. Baseline blood pressure was significantly lower in nephrectomized rats compared with controls. Nephrectomy, captopril, sham operation, or dialysis did not influence baseline CBF. The lower limit of CBF autoregulation was significantly lower in nephrectomized (53 +/- 4 mmHg) and sham-operated (58 +/- 4 mmHg) rats compared with diet control rats (78 +/- 3 mmHg). Captopril significantly decreased the lower limit in nephrectomized rats (35 +/- 2 mmHg). Thus removal of circulating renin caused no change in the lower limit of autoregulation. By contrast, captopril lowered the lower limit even in the absence of circulating renin and hence appeared to exert its effect on components of the renin-angiotensin system in the cerebral resistance vessel walls.</p

Mutational Analysis of Field Cancerization in Bladder Cancer

BACKGROUND: Morphologically normal tissue, adjacent to tumors, contains multiple molecular changes, the so-called field cancerization. The multifocal and recurrent nature of bladder cancer has been hypothesized to originate from this. However, further studies are required to explore the mutational composition of normal tissue adjacent to tumors. OBJECTIVE: To analyze field cancerization in bladder cancer patients using a non-tumor guided approach. METHODS: We investigated the mutational landscape of normal appearing urothelium and paired bladder tumors from four patients by applying deep-targeted sequencing. RESULTS: Sequencing of 509 cancer driver genes revealed the presence of 2– 13 mutations exclusively localized in normal tissue (average target read depth 634×). Furthermore, 6– 13 mutations were shared between tumor and normal samples and 8– 75 mutations were exclusively detected in tumor samples. More mutations were observed in normal samples from patients with multifocal disease compared to patients with unifocal disease. Mutations in normal samples had lower variant allele fractions (VAF) compared to tumor mutations (p &lt; 2.2*10–16). Furthermore, significant differences in the type of nucleotide changes between tumor, normal and shared mutations (p = 2.2*10–5) were observed, and mutations in APOBEC context were observed primarily among tumor mutations (p = 0.02). No differences in functional impact between normal, shared and tumor mutations were observed (p = 0.61). CONCLUSION: Overall, these findings support the presence of more than one field in the bladder, and document non-tumor specific driver mutations to be present in normal appearing bladder tissue.</jats:p

Abstract 1282: Elevated T cell exhaustion and immune cell infiltration is associated with BCG failure in patients with non-muscle invasive bladder cancer

Abstract Introduction: Gold standard treatment in patients with high-risk non-muscle invasive bladder cancer (NMIBC) includes Bacillus Calmette-Guérin (BCG), which activates the immune cells to kill remaining cancerous cells after surgical removal of the tumors. However, 40% of patients do not have a clinical benefit of BCG. The presence of immune cells, their functional state, as well as genomic alterations in the tumor and the normal appearing urothelial tissue, defined as field effect, may have significant impact on therapeutic outcome. Materials and methods: To investigate this, we analyzed samples from 156 patients diagnosed with NMIBC, including 237 tumors, 569 urine samples, and 305 biopsies of adjacent normal appearing urothelium. Patients had a median follow-up time of 8 years. 70 patients (45%) progressed to muscle-invasive bladder cancer or experienced early high grade recurrence within two years after ended BCG treatment, defined as BCG failure. Urinary levels of 92 immune-oncology related proteins were measured in pre- and post-treatment samples using the Olink proteomics platform. Total RNA- and whole exome sequencing (WES) data was generated from tumors before and after BCG. Clonal patient-specific mutations were selected for deep-targeted sequencing of the adjacent normal appearing biopsies. The level of field effect was defined as the mean of the variant allele frequency for mutations observed in normal biopsies. Results: We found that treatment with BCG activated the immune system regardless of clinical outcome. However, patients differed in urinary protein profile after BCG depending on their clinical response. Transcriptomic analysis of tumors showed that UROMOL2021 subtypes were significantly associated with outcome and clinical response (p=0.018). Paired tumors showed a shift in subtype to an immune infiltrated subtype (class 2b) after treatment in 36% of cases. Patients with BCG failure showed signs of immune exhaustion after treatment indicated by higher expression of the T cell exhaustion marker genes CTLA4 (p=0.0067), LAG3 (p=0.00012), TIM-3 (p=0.022), KLRG1 (p=0.028), and PD-1 (p=0.047), and higher immune cell infiltration (p=0.011). Genomic features such as mutational signatures and mutational load were not predictive of clinical response. Interestingly, BCG-responsive patients had a high level of field effect before BCG (p=0.0026), suggesting that field effect could lead to increased BCG efficacy. Conclusion: BCG treatment was associated with immune system activation reflected in both urine and tissue samples. In patients with BCG failure, we observed an immune exhausted phenotype after treatment, and we observed a high level of field effect before treatment in responsive patients. Collectively, this could indicate that increased immunogenicity and prolonged immune activation are key factors in BCG treatment responsiveness. Citation Format: Trine Strandgaard, Iver Nordentoft, Emil Christensen, Sia Lindskrog, Philippe Lamy, Karin Birkenkamp-Demtröder, Torben Steiniche, Jørgen Bjerggaard Jensen, Lars Dyrskjøt. Elevated T cell exhaustion and immune cell infiltration is associated with BCG failure in patients with non-muscle invasive bladder cancer [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 1282.</jats:p

Single-nucleus and Spatially Resolved Intratumor Subtype Heterogeneity in Bladder Cancer

Background: Current bulk transcriptomic classification systems for bladder cancer do not consider the level of intratumor subtype heterogeneity. Objective: To investigate the extent and possible clinical impact of intratumor subtype heterogeneity across early and more advanced stages of bladder cancer. Design, setting, and participants: We performed single-nucleus RNA sequencing (RNA-seq) of 48 bladder tumors and additional spatial transcriptomics for four of these tumors. Total bulk RNA-seq and spatial proteomics data were available from the same tumors for comparison, along with detailed clinical follow-up of the patients. Outcome measurements and statistical analysis: The primary outcome was progression-free survival for non–muscle-invasive bladder cancer. Cox regression analysis, log-rank tests, Wilcoxon rank-sum tests, Spearman correlation, and Pearson correlation were used for statistical analysis. Results and limitations: We found that the tumors exhibited varying levels of intratumor subtype heterogeneity and that the level of subtype heterogeneity can be estimated from both single-nucleus and bulk RNA-seq data, with high concordance between the two. We found that a higher class 2a weight estimated from bulk RNA-seq data is associated with worse outcome for patients with molecular high-risk class 2a tumors. The sparsity of the data generated using the DroNc-seq sequencing protocol is a limitation. Conclusions: Our results indicate that discrete subtype assignments from bulk RNA-seq data may lack biological granularity and that continuous class scores may improve clinical risk stratification of patients with bladder cancer. Patient summary: We found that several molecular subtypes can exist within a single bladder tumor and that continuous subtype scores can be used to identify a subgroup of patients with poor outcomes. Use of these subtype scores may improve risk stratification for patients with bladder cancer, which can help in making decisions on treatment