Familial adenomatous polyposis (FAP) is caused by germline mutations in the tumor suppressor gene APC. To date, nearly 2000 APC mutations have been described in FAP, most of which are predicted to result in truncated protein products. Mutations leading to aberrant APC splicing have rarely been reported. Here, we characterized a novel germline heterozygous splice donor site mutation in APC exon 12 (NM_000038.5: c.1621_1626+7del) leading to exon 12 skipping in an Italian family with the attenuated FAP (AFAP) phenotype. Moreover, we performed a literature me-ta-analysis of APC splicing mutations. We found that 123 unique APC splice site mutations, in-cluding the one described here, have been reported in FAP patients, 69 of which have been char-acterized at the mRNA level. Among these, only a small proportion (9/69) results in an in-frame protein, with 4 mutations causing skipping of exon 12 and/or 13 with loss of armadillo repeat 2 (ARM2) and 3 (ARM3), and 5 mutations leading to skipping of exon 5, 7, 8, and (partially) 9 with loss of regions not encompassing known functional domains. The APC splicing mutations considered in this study cluster with the AFAP phenotype and delineate a novel molecular mechanism of pathogenesis in FAP disease.

Much of the debate on Plan S seems to concentrate on how to make toll access journals open access, taking for granted that existing open access journals are Plan S compliant. We suspected this was not so, and set out to explore this using DOAJ's journal metadata. We conclude that an overwhelmingly large majority of open access journals are not Plan S compliant, and that it is small HSS publishers not charging APCs that are least compliant and will face major challenges with becoming compliant. Plan S need to give special considerations to smaller publishers and/or non-APC-based journals.

APC mutation is the main driver mechanism of CRC development and leads to constitutively activated WNT signaling, overpopulation of ALDH+ stem cells (SCs), and incomplete differentiation. We previously reported that retinoic acid (RA) receptors are selectively expressed in ALDH+ SCs, which provides a way to target cancer SCs with retinoids to induce differentiation. Hypotheses: A functional link exists between WNT and RA pathways, and APC mutation generates a WNT:RA imbalance that decreases retinoid-induced differentiation and increases ALDH+ SCs. Accordingly, to restore parity in WNT:RA signaling, we induced wt-APC expression in APC-mutant CRC cells and assessed the ability of all-trans-retinoic acid (ATRA) to induce differentiation. Notably, ATRA substantially increased expression of the WNT-target gene, CYP26A1, and inducing wt-APC reduced this expression by 50%. Thus, RA and WNT pathways crosstalk to modulate CYP26A1 metabolism of retinoids. We found that inducing wt-APC augments ATRA-induced cell differentiation by: i) decreasing cell proliferation; ii) suppressing ALDH1A1 expression; iii) decreasing ALDH+ SCs; iv) increasing neuroendocrine cell differentiation. Furthermore, NanoString profiling/bioinformatics identified a novel CYP26A1-based network that links WNT and RA signaling. Moreover, CYP26A1 inhibitors sensitized CRC cells to the anti-proliferative effect of drugs that downregulate WNT signaling. Notably. in wt-APC-CRCs, decreased CYP26A1 improves patient survival. These findings have strong potential for clinical translation.

Activation of the NLRP3 inflammasome plays a crucial role in innate immune response. During cell division, the NLRP3 inflammasome activation must be strictly controlled. Here, we discovered the anaphase promoting complex subunit 10 (Anapc10, APC10), a substrate recognition protein of the anaphase promoting complex/cyclosome (APC/C), is a critical mediator of the NLRP3 inflammasome activation. APC10 protein interacts with NLRP3, and co-localizes with NLRP3 protein in the cytoplasm. During interphase, APC10 interacts with NLRP3 to promote the NLRP3 inflammasome activation. During mitosis, APC10 disassociates from the NLRP3 inflammasome to inhibit the inflammatory responses. This study reveals a distinct mechanism by which APC10 serves as a switch of the NLRP3 inflammasome activation during cell cycle.