LSD1 inhibition suppresses ASCL1 and de-represses YAP1 to drive potent activity against neuroendocrine prostate cancer.

Lysine-specific demethylase 1 (LSD1 or KDM1A ) has emerged as a critical mediator of tumor progression in metastatic castration-resistant prostate cancer (mCRPC). Among mCRPC subtypes, neuroendocrine prostate cancer (NEPC) is an exceptionally aggressive variant driven by lineage plasticity, an adaptive resistance mechanism to androgen receptor axis-targeted therapies. Our study shows that LSD1 expression is elevated in NEPC and associated with unfavorable clinical outcomes. Using genetic approaches, we validated the on-target effects of LSD1 inhibition across various models. We investigated the therapeutic potential of bomedemstat, an orally bioavailable, irreversible LSD1 inhibitor with low nanomolar potency. Our findings demonstrate potent antitumor activity against CRPC models, including tumor regressions in NEPC patient-derived xenografts. Mechanistically, our study uncovers that LSD1 inhibition suppresses the neuronal transcriptional program by downregulating ASCL1 through disrupting LSD1:INSM1 interactions and de-repressing YAP1 silencing. Our data support the clinical development of LSD1 inhibitors for treating CRPC - especially the aggressive NE phenotype. Statement of Significance: Neuroendocrine prostate cancer presents a clinical challenge due to the lack of effective treatments. Our research demonstrates that bomedemstat, a potent and selective LSD1 inhibitor, effectively combats neuroendocrine prostate cancer by downregulating the ASCL1- dependent NE transcriptional program and re-expressing YAP1.

T cell-derived interferon-γ programs stem cell death in immune-mediated intestinal damage.

Despite the importance of intestinal stem cells (ISCs) for epithelial maintenance, there is limited understanding of how immune-mediated damage affects ISCs and their niche. We found that stem cell compartment injury is a shared feature of both alloreactive and autoreactive intestinal immunopathology, reducing ISCs and impairing their recovery in T cell-mediated injury models. Although imaging revealed few T cells near the stem cell compartment in healthy mice, donor T cells infiltrating the intestinal mucosa after allogeneic bone marrow transplantation (BMT) primarily localized to the crypt region lamina propria. Further modeling with ex vivo epithelial cultures indicated ISC depletion and impaired human as well as murine organoid survival upon coculture with activated T cells, and screening of effector pathways identified interferon-γ (IFNγ) as a principal mediator of ISC compartment damage. IFNγ induced JAK1- and STAT1-dependent toxicity, initiating a proapoptotic gene expression program and stem cell death. BMT with IFNγ-deficient donor T cells, with recipients lacking the IFNγ receptor (IFNγR) specifically in the intestinal epithelium, and with pharmacologic inhibition of JAK signaling all resulted in protection of the stem cell compartment. In addition, epithelial cultures with Paneth cell-deficient organoids, IFNγR-deficient Paneth cells, IFNγR-deficient ISCs, and purified stem cell colonies all indicated direct targeting of the ISCs that was not dependent on injury to the Paneth cell niche. Dysregulated T cell activation and IFNγ production are thus potent mediators of ISC injury, and blockade of JAK/STAT signaling within target tissue stem cells can prevent this T cell-mediated pathology.

Mucinous borderline tumours of the ovary and the appendix: a retrospective study and overview of the literature.

OBJECTIVES: Appendectomy is often recommended in patients with mucinous borderline ovarian tumours (mBOTs) based on studies suggesting that metastatic disease from a primary appendiceal tumour can mimic mBOT. The present study assessed the incidence of mucinous neoplasms in the appendix associated with the presence of mBOT. METHODS: A retrospective cohort study was performed in two university hospitals in the Netherlands between 1990 and 2011. All patients with mBOT and/or a mucinous appendiceal tumour were included. RESULTS: Of 127 patients included, 98 had a primary mBOT and 29 had a primary mucinous appendiceal tumour. In patients with a mBOT, the appendix was either removed at prior surgery (4%), resected as part of the staging procedure showing no pathological abnormalities (13%), described as normal and not resected (58%), or not described and not resected (25%). During a median follow-up period of 5 years (range 2-23), two patients developed a recurrence in which the appendix was not involved. In all patients with a primary mucinous tumour of the appendix, the appendix appeared abnormal at the time of surgery. Eight of these patients (28%) were diagnosed with invasive ovarian metastases. A review of the literature including the cases from this study identified 510 mucinous ovarian tumours with borderline features and 214 associated appendectomies, of which 4 (1.9%) contained a primary appendiceal malignancy. CONCLUSIONS: A thorough inspection of the appendix should be performed in patients with a mucinous ovarian tumour with borderline features. An appendectomy should only be performed when the appendix is macroscopically abnormal.

Lymph-node metastasis in stage I and II sex cord stromal and malignant germ cell tumours of the ovary: a systematic review.

OBJECTIVES: The aim of this systematic review is to determine the incidence of lymph-node metastasis in clinical stage I and II sex cord stromal tumours and germ cell tumours of the ovary. METHODS: Relevant articles were identified from MEDLINE and EMBASE and supplemented with citations from the reference lists of the primary studies. Eligibility was determined by two authors. Included studies were prospective or retrospective cohort and cross-sectional studies analysing at least ten patients with clinical early-stage non-epithelial ovarian cancer who underwent lymphadenectomy or lymph-node sampling as part of a staging laparotomy. RESULTS: For sex cord stromal tumours, five articles including 578 patients were analysed and lymph-node metastasis was not detected in the 86 patients who underwent lymph-node removal. The median number of removed lymph nodes was 13 (range 9-29). For malignant germ cell tumours, three articles were eligible including 2436 patients of whom 946 patients underwent lymph-node resection. The mean number of removed nodes was 10 (range 2-14) with a mean incidence of lymph-node metastasis of 10.9% (range 10.5-11.8%). CONCLUSIONS: The incidence of lymph-node metastasis in patients with clinical stage I and II sex cord stromal tumours is low, whereas the incidence in patients with clinical stage I-II germ cell tumours is considerable, although limited data are available.

Toll-like receptor alterations in myelodysplastic syndrome.

Recent studies have implicated the innate immunity system in the pathogenesis of myelodysplastic syndromes (MDS). Toll-like receptor (TLR) genes encode key innate immunity signal initiators. We recently identified multiple genes, known to be regulated by TLRs, to be overexpressed in MDS bone marrow (BM) CD34+ cells, and hypothesized that TLR signaling is abnormally activated in MDS. We analyzed a large cohort of MDS cases and identified TLR1, TLR2 and TLR6 to be significantly overexpressed in MDS BM CD34+ cells. Deep sequencing followed by Sanger resequencing of TLR1, TLR2, TLR4 and TLR6 genes uncovered a recurrent genetic variant, TLR2-F217S, in 11% of 149 patients. Functionally, TLR2-F217S results in enhanced activation of downstream signaling including NF-κB activity after TLR2 agonist treatment. In cultured primary BM CD34+ cells of normal donors, TLR2 agonists induced histone demethylase JMJD3 and interleukin-8 gene expression. Inhibition of TLR2 in BM CD34+ cells from patients with lower-risk MDS using short hairpin RNA resulted in increased erythroid colony formation. Finally, RNA expression levels of TLR2 and TLR6, as well as presence of TLR2-F217S, are associated with distinct prognosis and clinical characteristics. These findings indicate that TLR2-centered signaling is deregulated in MDS, and that its targeting may have potential therapeutic benefit in MDS.

Lymph node metastasis in stages I and II ovarian cancer: a review.

OBJECTIVES: The purpose of this review is to determine the incidence of lymph node metastases in clinical stages I and II ovarian cancer. METHODS: Relevant articles were identified from MEDLINE and EMBASE, supplemented with citations from reference lists from the primary studies. Eligibility was evaluated by two authors. Included studies were prospective or retrospective cohort studies, which analyzed patients with clinical early stage EOC who underwent a complete pelvic and para-aortic lymphadenectomy as a part of a staging laparotomy. RESULTS: Fourteen studies were included in the analysis. The mean incidence of lymph node metastases in clinical stages I-II EOC was 14.2% (range 6.1-29.6%), of which 7.1% only in the para-aortic region, 2.9% only in the pelvic region, and 4.3% both in the para-aortic and pelvic region. Grade 1 tumors had a mean incidence of lymph node metastases of 4.0%, grade 2 tumors 16.5.8% and grade 3 tumors 20.0%. According to histological subtype, the highest incidence of lymph node metastases was found in the serous subtype (23.3%), the lowest in the mucinous subtype (2.6%). In unilateral tumors, pelvic lymph node metastases were found in 9.7% on both sides, 8.3% only at the ipsilateral side, and in 3.5% only at the contralateral side. CONCLUSIONS: The incidence of lymph node metastases in clinical early stage EOC is considerable. Based on the scarce literature data, omitting a systematic lymphadenectomy can only be considered in grade I mucinous tumors.