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High-grade or grade 3 epithelial neuroendocrine neoplasms (G3 NEN) are now divided into grade 3 well-differentiated neuroendocrine tumor (G3 NET) and neuroendocrine carcinoma (NEC), both defined by Ki-67 > 20% and/or > 20 mitoses per 2 mm2. NET and NEC are thought to be distinct tumors with different genetic profiles: NEC classically harbors co-alteration of TP53 and RB1, whereas NET genetics are site-dependent with frequent alterations in MEN1, ATRX, DAXX, and TSC1/2 in pancreatic NETs. Progression from NET to NEC is considered rare and is not well described. While both TP53 and RB1 alterations were initially thought to be rare in NET, recent work has demonstrated the former in up to 35% of high-grade G3 NET and the latter in rare high-grade NEN that progressed from NET. Here, we describe the clinical, pathologic, and molecular features associated with tumor evolution in a series of five patients that had low-grade NET that progressed to high-grade NEN with co-alteration of RB1 and TP53, similar to NEC. Morphology of the high-grade neoplasms remained well-differentiated in some cases despite RB1/TP53 co-alteration and had some NEC-like features in other cases. All five patients died of disease, with a mean overall survival of 41 months from the first metastatic disease and 12 months from acquisition of RB1/TP53 co-alteration. Our data demonstrate that low-grade NET can progress via the acquisition of both TP53 and RB1 alteration, similar to NEC, but whether this represents a transformation from NET to NEC remains unclear.

Mutations in human nonsense-mediated mRNA decay (NMD) factors are enriched in neurodevelopmental disorders. We show that deletion of key NMD factor Upf2 in mouse embryonic neural progenitor cells causes perinatal microcephaly but deletion in immature neurons does not, indicating NMD's critical roles in progenitors. Upf2 knockout (KO) prolongs the cell cycle of radial glia progenitor cells, promotes their transition into intermediate progenitors, and leads to reduced upper-layer neurons. CRISPRi screening identified Trp53 knockdown rescuing Upf2KO progenitors without globally reversing NMD inhibition, implying marginal contributions of most NMD targets to the cell cycle defect. Integrated functional genomics shows that NMD degrades selective TRP53 downstream targets, including Cdkn1a, which, without NMD suppression, slow the cell cycle. Trp53KO restores the progenitor cell pool and rescues the microcephaly of Upf2KO mice. Therefore, one physiological role of NMD in the developing brain is to degrade selective TRP53 targets to control progenitor cell cycle and brain size.

The chromatin-associated protein WD Repeat Domain 5 (WDR5) is a promising target for cancer drug discovery, with most efforts blocking an arginine-binding cavity on the protein called the WIN site that tethers WDR5 to chromatin. WIN site inhibitors (WINi) are active against multiple cancer cell types in vitro, the most notable of which are those derived from MLL-rearranged (MLLr) leukemias. Peptidomimetic WINi were originally proposed to inhibit MLLr cells via dysregulation of genes connected to hematopoietic stem cell expansion. Our discovery and interrogation of small-molecule WINi, however, revealed that they act in MLLr cell lines to suppress ribosome protein gene (RPG) transcription, induce nucleolar stress, and activate p53. Because there is no precedent for an anticancer strategy that specifically targets RPG expression, we took an integrated multi-omics approach to further interrogate the mechanism of action of WINi in human MLLr cancer cells. We show that WINi induce depletion of the stock of ribosomes, accompanied by a broad yet modest translational choke and changes in alternative mRNA splicing that inactivate the p53 antagonist MDM4. We also show that WINi are synergistic with agents including venetoclax and BET-bromodomain inhibitors. Together, these studies reinforce the concept that WINi are a novel type of ribosome-directed anticancer therapy and provide a resource to support their clinical implementation in MLLr leukemias and other malignancies.

Cancer therapies have attempted to target the transcription factor p53, a gene also described as the "guardian of the genome," for decades. However, the approach has faced numerous barriers to clinical efficacy due to several factors: mutations in p53 occur in almost half of all human cancers, mutations are cancer-specific, and the associated genomic changes grant mutant p53 with oncogenic potential unique from that of wild-type p53. A host of new therapeutic agents have emerged that work to target mutant p53. These agents can broadly be classified into six categories: the viral approach, direct modifiers of the p53 pathway, epigenetic modifiers of the p53 pathway, synthetic lethal agents, structural reactivators, and immune activating vaccines. Even these strategies have been met with limited success. Bypassing p53 entirely may be the next avenue in cancer therapeutics to kill tumor cells regardless of p53's mutation pattern. [ABSTRACT FROM AUTHOR]

Background: Prostate Tumor Overexpressed 1 (PTOV1) is overexpressed and associated with malignant phenotypes in various types of tumors. However, the detailed roles of PTOV1 and its underlying mechanism in CRC remain unclear. Methods: The clinical significance of PTOV1 was assessed in clinical databases and CRC samples. The effects of PTOV1 on the tumor-associated phenotypes of CRC were detected by several in vitro assays and in vivo mouse models. Immunoprecipitation (IP) combined with protein mass spectrometry and Co-Immunoprecipitation (Co-IP) was used to identify p53 interacting with PTOV1. Immunofluorescence assay, western blot and transmission electron microscopy (TEM) analysis were used to evaluated the effects of PTOV1 on autophagy. Results: Here, we revealed that PTOV1 was highly expressed in human CRC tissues, especially at advanced stages, and associated with reduced survival time among CRC patients. The upregulated PTOV1 promoted cell proliferation, migration, invasion, tumor growth and metastasis of CRC cells in vitro and in vivo. At the molecular level, PTOV1 destabilized p53 by activating autophagy and recruiting p53 for the cargo receptor SQSTM1 directed autophagic degradation. There was a negative expression correlation between PTOV1 and p53 in CRC tissues. Moreover, p53 overexpression or SQSTM1 knockdown reversed the pro-tumor phenotypes of PTOV1 in CRC. Conclusion: Our study unveils the oncogenic role of PTOV1 in CRC progression, which was achieved by promoting SQSTM1 directed autophagic degradation of p53. These findings highlight the potential of targeting the PTOV1-SQSTM1-p53 axis as a therapeutic approach for CRC. [ABSTRACT FROM AUTHOR]

Simple Summary: Multiple myeloma (MM) is characterized by monoclonal plasma cell proliferation in the bone marrow. p53 plays a critical role in MM and the 17p deletion is associated with poor clinical outcomes. Rho-GTPase signaling, which includes Ras-related C3 botulinum toxin substrate 1 (Rac1) as a major regulator, is involved in cancer progression and chemoresistance; however, the role of Rac1 in MM remains elusive. This study was conducted to evaluate the role of Rac1 in MM. The results revealed that Rac1 affected the survival of human MM cell lines (HMCLs) independent of p53 status. High RAC1 mRNA expression in the intramedullary plasma cells of patients with NDMM was associated with poor overall survival. The Rac1 inhibitor intensified the effect of cereblon modulators on HMCLs. This study presents new insights into developing novel therapies targeting the Rac1 pathway, potentially improving the prognosis of patients with MM, including those with Wild Type p53 deficiency. Background/Objectives: Rho-GTPase signaling is involved in cancer progression and chemoresistance, with Ras-related C3 botulinum toxin substrate 1 (Rac1) being a major regulator. However, the role of Rac1 in multiple myeloma (MM) progression and its relationship with p53 and chemoresistance remains elusive. This study was conducted to evaluate the role of Rac1 in MM. Methods: Human MM cell lines (HMCLs), specifically KMS11, KMS26, and MM.1S, were treated with the Rac1 inhibitor 1A-116. The RAC1 mRNA levels in the purified bone marrow (BM) plasma cells of patients with newly diagnosed MM (NDMM) were measured using real-time quantitative PCR. Results: HMCLs exhibited reduced viability after treatment with 1A-116, independent of the p53 status. 1A-116 suppressed the cell cycle and induced apoptosis. Furthermore, 1A-116 intensified the effect of cereblon modulators on HMCLs but did not exhibit a synergistic effect with bortezomib. A total of 114 patients with NDMM, 70 with monoclonal gammopathy of undetermined significance and 15 controls, were enrolled in this study. The RAC1 mRNA levels in purified BM plasma cells were higher in patients with NDMM than in the controls. Patients with high RAC1 mRNA expression had a significantly shorter median time of overall survival (OS). In multivariate analysis of autologous stem cell transplantation (ASCT), revised international staging system, and RAC1 gene expression, high RAC1 mRNA levels and ASCT were identified as independent prognostic factors of OS. Conclusions: This study provided new insights into developing novel therapies targeting the Rac1 pathway and improving the prognosis of patients with MM, including those with p53 deficiency and mutation. [ABSTRACT FROM AUTHOR]

The p53 protein is a tumor-suppressing transcription factor that is critical in tumorigenesis. While TP53 mutations are rare in differentiated thyroid cancer (DTC), they are significantly more common in anaplastic thyroid cancer (ATC). This study presents original results and a meta-analysis reevaluating the prognostic value of TP53 mutations in thyroid cancer, including surrogate markers such as immunohistochemical p53 expression and serum p53-Abs levels. TP53 mutations were analyzed using SSSP and direct sequencing in a DTC group (15 patients), an ATC group (3 patients), and a control group (25 patients). The immunohistochemical p53 expression was assessed in tissue samples. A meta-analysis of 14 eligible studies identified through the PubMed, Scopus, Google Scholar, and Cochrane databases was conducted. Our results showed TP53 mutations in all ATC cases, 6.67% of DTC cases (1 out of 15), and none in the control group. Immunohistochemical p53 overexpression was observed in 4 out of 15 DTC (26.67%) and all ATC cases but absent in controls. A meta-analysis confirmed that TP53 mutations are significantly more frequent in ATC than controls (OR 8.95; 95% CI: 1.36–58.70; p = 0.02) but not in DTC vs. controls (OR 1.87; 95% CI: 0.53–6.58; p = 0.33). p53 overexpression was significantly higher in both DTC and ATC vs. controls (OR 7.99; 95% CI: 5.11–12.51; p < 0.01 and OR 64.37; 95% CI: 27.28–151.89; p < 0.01, respectively). The serum p53-Abs positivity was also elevated in patients with PTC vs. controls (OR 2.07; 95% CI: 1.24–3.47; p < 0.01). TP53 mutations are frequent events in the pathogenesis of ATC. In DTC, further prospective studies are needed to determine the prognostic value of TP53 mutations and related surrogate markers (immunohistochemical p53 expression, p53-Abs positivity). [ABSTRACT FROM AUTHOR]

Background: Circular RNAs play an important role in regulating lung adenocarcinoma (LUAD). Bioinformatics analysis identified circ_0015278 as differentially expressed in LUAD. However, the biological mechanism of circ_0015278 in LUAD has not been fully clarified, especially in ferroptosis. Materials and Methods: Bioinformatics analysis was employed to explore the downstream mechanisms of Circ_0015278, subsequently confirmed by luciferase reporter assays. The impact of Circ_0015278 on cell proliferation, migration, invasion, and ferroptosis was investigated through a loss-of-function experiment. A xenotransplantation mouse model elucidated the effect of Circ_0015278 on tumour growth. Results: Circ_0015278 exhibited downregulation in LUAD. It inhibited cell proliferation, migration, and invasion while promoting ferroptosis by interacting with miR-1228 to regulate P53 expression through a competitive endogenous RNA mechanism. Moreover, circ_0015278 suppressed tumour growth in mice. Conclusions: Circ_0015278 was identified as a novel factor promoting ferroptosis in LUAD. Furthermore, it suppressed the malignant progression of LUAD through the miR-1228/P53 axis. [ABSTRACT FROM AUTHOR]

Background: Regeneration is the preferred approach to restore the structure and function after tissue damage. Rapid proliferation of cells over the site of damage is integral to the process of regeneration. However, even subtle mutations in proliferating cells may cause detrimental effects by eliciting abnormal differentiation. Interestingly deer antlers, arguably the fastest regenerating mammalian tissue, have not been reported, thus far, to grow malignant tumors. They provide a mammalian model to understand the possible mechanism by which rapid regeneration is achieved while avoiding the development of malignancies. Antler regeneration is based on the proliferation and differentiation of antler stem cells (AnSCs). Results: We identified 39 hub genes which may function in regulating the balance between rapid proliferation and genomic stability in the AnSCs during antler regeneration. Among these 39 genes, the tumor suppressor gene, BRCA1, was found to be more sensitive to DNA damage in the AnSCs compared to that in the deer somatic cells, and BRCA1 deletion in the AnSCs via CRISPR/Cas9 resulted in significantly higher levels of DNA damage. Lack of BRCA1 promoted cell apoptosis and cell senescence and inhibited cell proliferation and cell self-renewal. RNA-seq results showed that in the absence of BRCA1, the p53 signaling pathway was significantly up-regulated. Associated with this change, the cell apoptosis and cell senescence-relevant-genes, CDKN1A, CDKN2A and Fas were over expressed, but the expression of cell-cycle-progression-related genes was inhibited. In addition, BRCA1 expression levels were found to be more sensitive to endoplasmic reticulum stress (ERS) in the AnSCs compared to the somatic cells. Deletion of BRCA1 gene aggravated ERS and ERS-induced cell apoptosis. Conclusions: Our results revealed that BRCA1 is involved in sustaining rapid antler growth possibly via promotion of DNA damage repair that acts to maintain genome stability while protecting cells from p53/ERS-induced cell death. Understanding the mechanisms underlying the role played by BRCA1 in the process of antler regeneration is of great significance not only for regenerative medicine, but also for the understanding of cancer development. [ABSTRACT FROM AUTHOR]

Breast cancer represents the primary cause of death of women under 65 in developed countries, due to the acquisition of multiple drug resistance mechanisms. The PI3K/AKT pathway is one of the major regulating mechanisms altered during the development of endocrine resistance and inhibition of steps in this signalling pathway are adopted as a key strategy to overcome this issue. ADP-ribosylation is a post-translational modification catalysed by PARP enzymes that regulates essential cellular processes, often altered in diseases. PARP12, a member of this family, has been associated with the onset of drug resistance in oestrogen receptor-positive breast cancers, making this enzyme a promising drug target. The molecular basis underlying its involvement in the acquisition of resistance are unknown to date. Here, we demonstrate that PARP12-mediated mono-ADP-ribosylation of AKT is required for AKT activation whilst the absence of PARP12 leads to apoptosis induction in a subset of oestrogen receptor-positive breast cancer cells. Our data show that transcriptional inhibition of PARP12 correlates with an increased DNA-damage induction, mirrored by augmented p53 nuclear localisation and enhanced p53-AKT interaction. Under these conditions, AKT is functionally incompetent towards its downstream targets FOXO, hence favouring cell death. This is achieved by increasing protein levels of the FOXO1 transcription factor, that in turn activates the apoptotic cascade. Overall, we show a novel regulation step of AKT activation and apoptosis relying on PARP12-mediated mono-ADP-ribosylation and propose PARP12 as a potential pharmacological target to be exploited as an innovative therapeutical strategy to overcome endocrine resistance. [ABSTRACT FROM AUTHOR]

Background: Understanding the risk factors for early recurrence is crucial for improving endometrial cancer (EC) patient outcomes. Methods: We conducted a retrospective analysis of clinicopathological data from 473 patients diagnosed with EC at the First Affiliated Hospital of Chongqing Medical University between October 2013 and May 2019. We evaluated factors influencing early recurrence(defined as occurring within 12 months after treatment) based on 2023 International Federation of Gynecology and Obstetrics (FIGO) staging system. Results: Among the 473 patients, 284 (60.1%) were diagnosed with stage I, 117 (24.7%) with stage II, and 72 (15.2%) with stage III. A total of 343 patients (72.5%) had non-aggressive EC, while 130 patients (27.5%) had aggressive EC. Our findings identified higher FIGO stage, lymphovascular space invasion, estrogen receptor negativity, and abnormal P53 expression as significant independent risk factors for early recurrence. Of the 473 patients, 83 (17.6%) experienced recurrence, with 44 patients (53.0%) relapsing within 12 months post-treatment. Patients with early recurrence had significantly worse prognoses compared to those with late recurrence or no recurrence(P < 0.001). Conclusion: The identification of these risk factors is essential for developing individualized treatment plans and postoperative management strategies. Our study highlights the need for targeted therapies and intensified follow-up for high-risk patients to improve outcomes in endometrial cancer. [ABSTRACT FROM AUTHOR]