Asparaginase-like protein 1 as a prognostic tissue biomarker in clinicopathologically and molecularly characterized endometrial cancer.

OBJECTIVE: Prognostic stratification of endometrial cancer involves the assessment of stage, uterine risk factors, and molecular classification. This process can be further refined through annotation of prognostic biomarkers, notably L1 cell adhesion molecule (L1CAM) and hormonal receptors. Loss of asparaginase-like protein 1 (ASRGL1) has been shown to correlate with poor outcome in endometrial cancer. Our objective was to assess prognostication of endometrial cancer by ASRGL1 in conjunction with other available methodologies. STUDY DESIGN: This was a retrospective study of patients who underwent primary treatment at a single tertiary center. Tumors were molecularly classified by the Proactive Molecular Risk Classifier for Endometrial Cancer. Expression of ASRGL1, L1CAM, estrogen receptor, and progesterone receptor was determined by immunohistochemistry. ASRGL1 expression intensity was scored into four classes. RESULTS: In a cohort of 775 patients, monitored for a median time of 81 months, ASRGL1 expression intensity was related to improved disease-specific survival in a dose-dependent manner (P < 0.001). Low expression levels were associated with stage II-IV disease and presence of uterine factors, i.e. high grade, lymphovascular space invasion, and deep myometrial invasion (P < 0.001 for all). Among the molecular subgroups, low expression was most prevalent in p53 abnormal carcinomas (P < 0.001). Low ASRGL1 was associated with positive L1CAM expression and negative estrogen and progesterone receptor expression (P < 0.001 for all). After adjustment for stage and uterine factors, strong ASRGL1 staining intensity was associated with a lower risk for cancer-related deaths (hazard ratio 0.56, 95 % confidence interval 0.32-0.97; P = 0.038). ASRGL1 was not associated with the outcome when adjusted for stage, molecular subgroups, L1CAM, and hormonal receptors. When analyzed separately within the different molecular subgroups, ASRGL1 showed an association with disease-specific survival specifically in "no specific molecular profile" subtype carcinomas (P < 0.001). However, this association became nonsignificant upon controlling for confounders. CONCLUSIONS: Low ASRGL1 expression intensity correlates with poor survival in endometrial cancer. ASRGL1 contributes to more accurate prognostication when controlled for stage and uterine factors. However, when adjusted for stage and other biomarkers, including molecular subgroups, ASRGL1 does not improve prognostic stratification.

Understanding the molecular crossroads in acute liver failure: A pathway to new therapies.

In this editorial we comment on the article published in a recent issue of the World Journal of Gastroenterology. Acute liver failure (ALF) is a critical condition characterized by rapid hepatocellular injury and organ dysfunction, and it often necessitates liver transplant to ensure patient survival. Recent research has elucidated the involvement of distinct cell death pathways, namely ferroptosis and pyroptosis, in the pathogenesis of ALF. Ferroptosis is driven by iron-dependent lipid peroxidation, whereas pyroptosis is an inflammatory form of cell death; both pathways contribute to hepatocyte death and exacerbate tissue damage. This comprehensive review explores the interplay between ferroptosis and pyroptosis in ALF, highlighting the role of key regulators such as silent information regulator sirtuin 1. Insights from clinical and preclinical studies provide valuable perspectives on the dysregulation of cell death pathways in ALF and the therapeutic potential of targeting these pathways. Collaboration across multiple disciplines is essential for translating the experimental insights into effective treatments for this life-threatening condition.

Suppression of P53 Pathway is an Important Factor Inducing Acute Graft-versus-Host Disease Through T Cell Activation Based on Bioinformatics Analysis.

Purpose: Acute graft-versus-host disease (aGVHD) poses a significant impediment to achieving a more favourable therapeutic outcome in allogeneic hematopoietic stem cell transplantation (allo-HSCT). The tumour suppressor p53 plays a pivotal role in preventing aGVHD development. However, whether P53 pathway which contains p53 family members and other related genes participates in aGVHD development remains an unsolved question. Patients and Methods: Transcriptomic data was obtained from Gene Expression Omnibus (GEO) database. Gene set enrichment analysis was applied to determine the enrichment degree of signaling pathways. CIBERSORT and ssGSVA were used to evaluate immune cell compositions. Univariate and multivariate logistic regression analysis were performed to examine the independent diagnostic variables. qRT-PCR was utilized to validate the genes expression levels in our cohort. Results: A total number of 102 patients (42 aGVHD patients vs 60 non-aGVHD patients) were obtained after integrating two datasets in GEO database (GSE73809 and GSE4624). P53 pathway was remarkably suppressed in T cells from aGVHD patients and negatively associated with activated T cells as well as T cells activation related signaling pathways, including T-cell receptor (TCR), mTORC1, MYC and E2F target pathways. A risk model for aGVHD built by four genes (DDIT3, FBXW7, TPRKB and TOB1) in P53 pathway, exhibiting high differentiate and predictive value. DDIT3 and FBXW7 mRNA expression levels significantly decreased in peripheral blood mononuclear cells (PBMCs) from aGVHD patients compared with non-aGVHD group in our patient cohort, consisting with bioinformatics analysis. Conclusion: P53 pathway plays a potential role in impeding T cell activation through suppressing its related signaling pathways, thereby preventing aGVHD development. P53 pathway may emerge as a promising therapeutic target in aGVHD treatment.

In vitro anticancer study of novel curcumin derivatives via targeting PI3K/Akt/p53 signaling pathway.

Four new series of curcumin derivatives bearing NO-donating moiety were synthesized via etherification, nucleophilic substitution, and Knoevenagel condensation etc. The cytotoxicity activity of curcumin derivatives against five human tumor cell lines (A549, Hela, HepG2, MCF-7 and HT-29) and two normal cell lines (LO-2 and HK-2) has been studied. The results showed that compound 6a could inhibit the proliferation of MCF-7 cells remarkably and exhibit low toxicity to normal cells. Also, the underlying mechanism in vitro of compound 6a on MCF-7 was investigated. It has been found that compound 6a induced G2/M arrest and apoptosis of MCF-7 in a dose-dependent manner. Compound 6a-induced the fluorescence changes of ROS in MCF-7 cells confirmed the occurrence of apoptosis. Western Blot suggested that compound 6a decreased the expression of PI3K, as well as increased the expression of p53, cleaved caspase-9 and cleaved caspase-3. Furthermore, molecular docking revealed that compound 6a could bind well at active site of PI3K (3zim) with total score 9.59. Together, compound 6a, a potential PI3K inhibitor, may inhibit the survival of MCF-7 cells via interfering with PI3K/Akt/p53 pathway.

YTHDC1 m6A-dependent and m6A-independent functions converge to preserve the DNA damage response.

Cells have evolved a robust and highly regulated DNA damage response to preserve their genomic integrity. Although increasing evidence highlights the relevance of RNA regulation, our understanding of its impact on a fully efficient DNA damage response remains limited. Here, through a targeted CRISPR-knockout screen, we identify RNA-binding proteins and modifiers that participate in the p53 response. Among the top hits, we find the m6A reader YTHDC1 as a master regulator of p53 expression. YTHDC1 binds to the transcription start sites of TP53 and other genes involved in the DNA damage response, promoting their transcriptional elongation. YTHDC1 deficiency also causes the retention of introns and therefore aberrant protein production of key DNA damage factors. While YTHDC1-mediated intron retention requires m6A, TP53 transcriptional pause-release is promoted by YTHDC1 independently of m6A. Depletion of YTHDC1 causes genomic instability and aberrant cancer cell proliferation mediated by genes regulated by YTHDC1. Our results uncover YTHDC1 as an orchestrator of the DNA damage response through distinct mechanisms of co-transcriptional mRNA regulation.

Interferons in Colorectal Cancer Pathogenesis and Therapy.

As key modulators of the immune response, interferons play critical roles following infection and during the pathogenesis of cancer. The idea that these cytokines might be developed as new therapies emerged soon after their discovery. While enthusiasm for this approach to cancer therapy has waxed and waned over the ensuing decades, recent advances in cancer immunotherapy and our improved understanding of the tumor immune environment have led to a resurgence of interest in this unique class of biologic drug. Here, we review how interferons influence the growth of colorectal cancers (CRCs) and highlight new insights into how interferons and drugs that modulate interferon expression might be most effectively deployed in the clinic.

HPV status and immunohistochemical analysis of p16, p53 and PD­L1 expression as prognostic biomarkers in patients with squamous cell anal cancer receiving definitive radiotherapy/chemoradiotherapy.

Anal squamous cell carcinoma (SCC) treated with definitive radiotherapy (RT)/chemoradiotherapy (CRT) has shown high success rates, yet challenges such as treatment resistance and recurrence persist. The present study aimed to investigate the associations between immunohistochemical (IHC) evaluation, treatment response and prognosis in anal SCC. A retrospective cohort analysis included 42 patients with anal SCC treated at a single institution between 2006 and 2022. Human papillomavirus (HPV) status was determined, and the IHC analysis of p16, p53 and PD-L1 expression was conducted using formalin-fixed, paraffin-embedded biopsies. A complete response to RT/CRT was observed in 71.4% of patients. Recurrence occurred in 38.1% of cases, of which 7.1% had local-regional recurrence (LRR), 14.3% had distant recurrence (DR), and 16.7% had both LRR and DR. HPV positivity (71.4%) was significantly associated with p16 positivity. Lack of complete response was associated with HPV-negative status, p16-negative status, increased recurrence and DR. In addition, recurrence was significantly associated with p53-positive status, and p53 positivity was significantly associated with increased LRR. PD-L1 positivity, defined as a combined positive score (CPS) ≥1% was found in 73.8% of the patients, and exhibited significant associations with HPV positivity and p16 positivity. PD-L1 CPS ≥ 1% was also associated with an increased LRR. Univariate analysis revealed that age <65 years, a complete response and HPV positivity were associated with increased 5-year overall survival (OS), while a complete response, HPV positivity and p53-negative status were associated with increased 5-year disease-free survival (DFS). Multivariate analysis identified that age <65 years and HPV positivity are independent prognostic factors for 5-year OS, and a complete response and p53-negative status are independent prognostic factors for 5-year DFS. In conclusion, these findings suggust that the identification of HPV status and poor prognostic biomarkers at diagnosis may be used to guide personalized treatment strategies, with the combination of immunotherapy with standard CRT potentially providing improved outcomes.

Hypoxia triggers cardiomyocyte apoptosis via regulating the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis.

Long-time hypoxia induced cardiomyocyte apoptosis is an important mechanism of myocardial ischemia (MI) injury. Interestingly, long noncoding RNA myocardial infarction-associated transcript (LncMIAT) has been involved in the regulation of MI injury; however, the underlying mechanism by which LncMIAT affects the progression of hypoxia-induced cardiomyocyte apoptosis remains unclear. In the present study, hypoxia was found to promote cardiomyocyte apoptosis through an increased expression of LncMIAT in vitro. Biological investigations and dual-luciferase gene reporter assay further revealed that LncMIAT was able to bind with miR-708-5p to upregulate the p53-mediated cell death of the cardiomyocytes. Silencing of LncMIAT or overexpression of miR-708-5p led to a significant reduction in p53-mediated cardiomyocyte apoptosis. The methylated RNA immunoprecipitation (MeRIP)-qPCR results showed that hypoxia exerted its effects on LncMIAT through AKLBH5-N6-methyladenosine (m6A) methylation and therefore hypoxia was shown to trigger HL-1 cardiomyocyte apoptosis via the m6A methylation-mediated LncMIAT/miR-708-5p/p53 axis. Silencing of AKLBH5 significantly alleviated the m6A methylation-mediated LncMIAT upregulation and p53-mediated cardiomyocyte apoptosis, while promoted miR-708-5p expression. Taken together, the present study highlighted that LncMIAT could act as a key biological target during hypoxia-induced cardiomyocyte apoptosis. In addition, it was shown that hypoxia could promote cardiomyocyte apoptosis through regulation of the m6A methylation-mediated LncMIAT/miR-708-5p/p53 signaling axis.

Hernandonine-mediated autophagic cell death in hepatocellular carcinoma: Interplay of p53 and YAP signaling pathways.

Hepatocellular carcinoma (HCC), the primary form of liver cancer, is the third leading cause of cancer-related death globally. Hernandonine is a natural alkaloid derived from Hernandia nymphaeifolia that has been shown to exert various biological functions. In a previous study, hernandonine was shown to suppress the proliferation of several solid tumor cell lines without affecting normal human cell lines. However, little is known about the effect of hernandonine on HCC. Therefore, this study aimed to investigate the effect and mechanism of hernandonine on HCC in relation to autophagy. We found that hernandonine inhibited HCC cell growth in vitro and in vivo. In addition, hernandonine elicited autophagic cell death and DNA damage in HCC cells. RNA-seq analysis revealed that hernandonine upregulated p53 and Hippo signaling pathway-related genes in HCC cells. Small RNA interference of p53 resulted in hernandonine-induced autophagic cell death attenuation. However, inhibition of YAP sensitized HCC cells to hernandonine by increasing the autophagy induction. This is the first study to illustrate the complex involvement of p53 and YAP in the hernandonine-induced autophagic cell death in human HCC cells. Our findings provide novel evidence for the potential of hernandonine as a therapeutic agent for HCC treatment.

ESF1 positively regulates MDM2 and promotes tumorigenesis.

Eighteen S rRNA factor 1 (ESF1) is a predominantly nucleolar protein essential for embryogenesis. Our previous studies have suggested that Esf1 is a negative regulator of the tumor suppressor protein p53. However, it remains unclear whether ESF1 contributes to tumorigenesis. In this current research, we find that increased ESF1 expression correlates with poor survival in multiple tumors including pancreatic cancer. ESF1 is able to regulate cell proliferation, migration, DNA damage-induced apoptosis, and tumorigenesis. Mechanistically, ESF1 physically interacts with MDM2 and is essential for maintaining the stability of MDM2 protein by inhibiting its ubiquitination. Additionally, ESF1 also prevented stress-induced stabilization of p53 in multiple cancer cells. Hence, our findings suggest that ESF1 is a potent regulator of the MDM2-p53 pathway and promotes tumor progression.

Exploring Ubiquitin-specific proteases as therapeutic targets in Glioblastoma.

Glioblastoma (GB) remains a formidable challenge and requires new treatment strategies. The vital part of the Ubiquitin-proteasome system (UPS) in cellular regulation has positioned it as a potentially crucial target in GB treatment, given its dysregulation oncolines. The Ubiquitin-specific proteases (USPs) in the UPS system were considered due to the garden role in the cellular processes associated with oncolines and their vital function in the apoptotic process, cell cycle regulation, and autophagy. The article provides a comprehensive summary of the evidence base for targeting USPs as potential factors for neoplasm treatment. The review considers the participation of the UPS system in the development, resulting in the importance of p53, Rb, and NF-κB, and evaluates specific goals for therapeutic administration using midnight proteasomal inhibitors and small molecule antagonists of E1 and E2 enzymes. Despite the slowed rate of drug creation, recent therapeutic discoveries based on USP system dynamics hold promise for specialized therapies. The review concludes with an analysis of future wanderers and the feasible effects of targeting USPs on personalized GB therapies, which can improve patient hydration in this current and unattractive therapeutic landscape. The manuscript emphasizes the possibility of USP oncogene therapy as a promising alternative treatment line for GB. It stresses the direct creation of research on the medical effectiveness of the approach.

A non-canonical role for a small nucleolar RNA in ribosome biogenesis and senescence.

Cellular senescence is an irreversible state of cell-cycle arrest induced by various stresses, including aberrant oncogene activation, telomere shortening, and DNA damage. Through a genome-wide screen, we discovered a conserved small nucleolar RNA (snoRNA), SNORA13, that is required for multiple forms of senescence in human cells and mice. Although SNORA13 guides the pseudouridylation of a conserved nucleotide in the ribosomal decoding center, loss of this snoRNA minimally impacts translation. Instead, we found that SNORA13 negatively regulates ribosome biogenesis. Senescence-inducing stress perturbs ribosome biogenesis, resulting in the accumulation of free ribosomal proteins (RPs) that trigger p53 activation. SNORA13 interacts directly with RPL23, decreasing its incorporation into maturing 60S subunits and, consequently, increasing the pool of free RPs, thereby promoting p53-mediated senescence. Thus, SNORA13 regulates ribosome biogenesis and the p53 pathway through a non-canonical mechanism distinct from its role in guiding RNA modification. These findings expand our understanding of snoRNA functions and their roles in cellular signaling.

PTEN Loss Is Associated with Adverse Outcomes in the Setting of Salvage Radiation Therapy.

BACKGROUND: Salvage radiation therapy (SRT) is a mainstay of treatment for biochemical relapse following radical prostatectomy; however, few studies have examined genomic biomarkers in this context. OBJECTIVE: We characterized the prognostic impact of previously identified deleterious molecular phenotypes-loss of PTEN, ERG expression, and TP53 mutation-for patients undergoing SRT. DESIGN, SETTING, AND PARTICIPANTS: We leveraged an institutional database of 320 SRT patients with available tissue and follow-up. Tissue microarrays were used for genetically validated immunohistochemistry assays. INTERVENTION: All men underwent SRT with or without androgen deprivation therapy OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Univariable and multivariable Cox-proportional hazard models assessed the association of molecular phenotypes with biochemical recurrence-free (bRFS) and metastasis-free (MFS) survival after SRT. RESULTS AND LIMITATIONS: Loss of PTEN (n = 123, 43%) and ERG expression (n = 118, 39%) were common in this cohort, while p53 overexpression (signifying TP53 missense mutation) was infrequent (n = 21, 7%). In univariable analyses, any loss of PTEN portended worse bRFS (hazard ratio [HR] 1.86; 95% confidence interval 1.36-2.57) and MFS (HR 1.89; 1.21-2.94), with homogeneous PTEN loss being associated with the highest risk of MFS (HR 2.47; 1.54-3.95). Similarly, p53 overexpression predicted worse bRFS (HR 1.95; 1.14-3.32) and MFS (HR 2.79; 1.50-5.19). ERG expression was associated with worse MFS only (HR 1.6; 1.03-2.48). On the multivariable analysis adjusting for known prognostic features, homogeneous PTEN loss remained predictive of adverse bRFS (HR 1.82; 1.12-2.96) and MFS (HR 2.08; 1.06-4.86). The study is limited by its retrospective and single-institution design. CONCLUSIONS: PTEN loss by immunohistochemistry is an independent adverse prognostic factor for bRFS and MFS in prostate cancer patients treated with SRT. Future trials will determine the optimal approach to treating SRT patients with adverse molecular prognostic features. PATIENT SUMMARY: Loss of the PTEN tumor suppressor protein is associated with worse outcomes after salvage radiotherapy, independent of other clinical or pathologic patient characteristics.

MARCH5 promotes hepatocellular carcinoma progression by inducing p53 ubiquitination degradation.

BACKGROUND: Human MARCH5 is a mitochondria-localized E3 ubiquitin-protein ligase that is essential for the regulation of mitochondrial dynamics. A large body of evidence suggests that imbalances in mitochondrial dynamics are strongly associated with cancer. However, the expression, biological function and prognostic significance of MARCH5 in hepatocellular carcinoma (HCC) have not been determined. MATERIALS AND METHODS: The mRNA and protein expression of MARCH5 in HCC cell lines and tumor tissues was assessed by real-time quantitative PCR, Western blot analysis and immunohistochemistry. The clinical prognostic significance of MARCH5 was evaluated in 135 HCC patients. Knockdown or overexpression of MARCH5 in HCC cells was determined by in vitro cell proliferation, migration and invasion assays, and in vivo tumor growth and metastasis assays. In addition, the intrinsic mechanisms by which MARCH5 regulates HCC cell growth and metastasis were explored. RESULTS: MARCH5 was significantly overexpressed in HCC cells and was closely associated with patients' poor postoperative prognosis. In vivo and in vitro experiments revealed that MARCH5 significantly promoted the increase and invasive and migratory ability of hepatocellular carcinoma cells, which was mainly due to the promotion of autophagy by MARCH5. Mechanistic studies revealed that MARCH5 promoted autophagy through ubiquitination degradation of p53 leading to malignant progression of hepatocellular carcinoma. CONCLUSION: Our findings suggest that MARCH5 plays a critical oncogenic role in HCC cells, which provides experimental evidence for the use of MARCH5 as a potential target for HCC therapy.

Influence of the interaction between p53 and ZNF568 on mitochondrial oxidative phosphorylation.

The tumor suppressor p53 plays important roles in suppressing the development and progression of cancer by responding to various stress signals. In addition, p53 can regulate the metabolic pathways of cancer cells by regulating energy metabolism and oxidative phosphorylation. Here, we present a mechanism for the interaction between p53 and ZNF568. Initially, we used X-ray crystallography to determine the irregular loop structure of the ZNF568 KRAB domain; this loop plays an important role in the interaction between p53 and ZNF568. In addition, Cryo-EM was used to examine how the p53 DBD and ZNF568 KRAB domains bind together. The function of ZNF568 on p53-mediated mitochondrial respiration was confirmed by measuring glucose consumption and lactate production. These findings show that ZNF568 can reduce p53-mediated mitochondrial respiratory activity by binding to p53 and inhibiting the transcription of SCO2. SIGNIFICANCE: ZNF568 can directly bind to the p53 DBD and transcriptionally regulate the SCO2 gene. SCO2 transcriptional regulation by interaction between ZNF568 and p53 may regulate the balance between mitochondrial respiration and glycolysis.

Metformin prevents mandibular bone loss in a mouse model of accelerated aging by correcting dysregulated AMPK-mTOR signaling and osteoclast differentiation.

Background: Age-related mandibular osteoporosis frequently causes loose teeth, difficulty eating, and disfiguration in elders. Bmi1-/- mice displaying accelerated skeletal aging represent a useful model for testing interventions against premature jaw bone loss. As an anti-aging agent, metformin may ameliorate molecular dysfunction driving osteoporosis pathogenesis. We explored the mechanisms of mandibular osteopenia in Bmi1-/- mice and prevention by metformin treatment. Methods: Three mouse groups were utilized: wild-type controls, untreated Bmi1-/-, and Bmi1-/- receiving 1 g/kg metformin diet. Mandibular bone phenotype was assessed by X-ray, micro-CT, histology, and immunohistochemistry. AMPK-mTOR pathway analysis, senescence markers, osteoblast and osteoclast gene expression were evaluated in jaw tissue. Osteoclast differentiation capacity and associated signaling molecules were examined in cultured Bmi1-/- bone marrow mononuclear cells ± metformin. Results: Bmi1 loss reduced mandible bone density concomitant with decreased AMPK activity, increased mTOR signaling and cellular senescence in jaw tissue versus wild-type controls. This was accompanied by impaired osteoblast function and upregulated osteoclastogenesis markers. Metformin administration normalized AMPK-mTOR balance, oxidative stress and senescence signaling to significantly improve mandibular bone architecture in Bmi1-/- mice. In culture, metformin attenuated excessive osteoclast differentiation from Bmi1-/- marrow precursors by correcting dysregulated AMPK-mTOR-p53 pathway activity and suppressing novel pro-osteoclastogenic factor Stfa1. Conclusions: Our study newly demonstrates metformin prevents accelerated jaw bone loss in a premature aging murine model by rectifying molecular dysfunction in cellular energy sensors, redox state, senescence and osteoclastogenesis pathways. Targeting such age-associated mechanisms contributing to osteoporosis pathogenesis may help maintain oral health and aesthetics in the growing elderly population. Translational potential: The pronounced mandibular osteopenia exhibited in Bmi1-/- mice represents an accelerated model of jaw bone deterioration observed during human aging. Our finding that metformin preserves mandibular bone integrity in this progeroid model has important clinical implications. As an inexpensive oral medication already widely used to manage diabetes, metformin holds translational promise for mitigating age-related osteoporosis. The mandible is essential for chewing, swallowing, speech and facial structure, but progressively loses bone mass and strength with advancing age, significantly impacting seniors' nutrition, physical function and self-image. Our results suggest metformin's ability to rectify cellular energy imbalance, oxidative stress and osteoclast overactivity may help maintain jaw bone health into old age. Further research is still needed given metformin's multifaceted biology and bone regulation by diverse pathways. However, this preclinical study provides a strong rationale for clinical trials specifically examining mandibular outcomes in elderly subjects receiving standard metformin treatment for diabetes or prediabetes. Determining if metformin supplementation can prevent or delay oral disability and disfigurement from senescent jaw bone loss in the growing aged population represents an important public health priority. In summary, our mechanistic findings in a genetic mouse model indicate metformin merits investigation in rigorous human studies for alleviating morbidity associated with age-related mandibular osteoporosis.

ZBTB7A interferes with the RPL5-P53 feedback loop and reduces endoplasmic reticulum stress-induced apoptosis of pancreatic cancer cells.

Endoplasmic reticulum (ER) stress is a primary mechanism leading to cell apoptosis, making it of great research interests in cancer management. This study delves into the function of ribosomal protein L5 (RPL5) in ER stress within pancreatic cancer (PCa) cells and investigates its regulatory mechanisms. Bioinformatics predictions pinpointed RPL5 as an ER stress-related gene exhibiting diminished expression in PCa. Indeed, RPL5 was found to be poorly expressed in PCa tissues and cells, with this reduced expression correlating with an unfavorable prognosis. Moreover, RPL5 overexpression led to heightened levels of p-PERK, p-eIF2α, and CHOP, bolstering the proapoptotic effect of Tunicamycin, an ER stress activator, on PCa cells. Additionally, the RPL5 overexpression curbed cell proliferation, migration, and invasion. Tunicamycin enhanced the binding between RPL5 and murine double minute 2 (MDM2), thus suppressing MDM2-mediated ubiquitination and degradation of P53. Consequently, P53 augmentation intensified ER stress, which further enhanced the binding between RPL5 and MDM2 through PERK-dependent eIF2α phosphorylation, thereby establishing a positive feedback loop. Zinc finger and BTB domain containing 7A (ZBTB7A), conspicuously overexpressed in PCa samples, repressed RPL5 transcription, thereby reducing P53 expression. Silencing of ZBTB7A heightened ER stress and subdued the malignant attributes of PCa cells, effects counteracted upon RPL5 silencing. Analogous outcomes were recapitulated in vivo employing a xenograft tumor mouse model, where ZBTB7A silencing dampened the tumorigenic potential of PCa cells, an effect reversed by additional RPL5 silencing. In conclusion, this study suggests that ZBTB7A represses RPL5 transcription, thus impeding the RPL5-P53 feedback loop and mitigating ER-induced apoptosis in PCa cells.

Cytoplasmic PPARγ Significantly Correlates With P53 Immunohistochemical Expression and Tumor Size in Localized Tenosynovial Giant Cell Tumor.

BACKGROUND: Tenosynovial giant cell tumor (TGCT) is a monoarticular fibrohistiocytic benign or locally aggressive soft tissue tumor that originates from the synovium of joints, bursae, and tendon sheaths. It has an inflammatory neoplastic nature, with a clinical presentation ranging from pain, swelling, stiffness, and limited range of movement to joint instability and blockage. Its uncommon incidence leads to a poorly understood pathogenesis. Localized forms of TGCT (LTGCT) can cause significant morbidity, interfere with daily patient activities, and decrease the patient's quality of life in challenging cases. This study aimed to investigate the immunohistochemical expression of PPARγ (peroxisome proliferator-activated receptor gamma) and P53 in LTGCT to understand the disease better and offer potential therapeutic targets. METHODS: The study is cross-sectional, in which 27 LTGCT cases were collected from the Pathology Department, Faculty of Medicine, Cairo University, Cairo, Egypt. Solitary and multiple LTGCT cases retrieved between January 2018 and December 2022 were included, and immunohistochemically stained with anti-PPARγ and P53 antibodies. The TGCT samples were excluded if they were insufficient for sectioning, processing, and interpretation, over-fixed, had process artifacts, or were of the diffuse TGCT type. Scoring of stain expression was performed by ImageJ (National Institutes of Health, Bethesda, MD) analysis using the threshold method and was expressed in percent area/high power field. Clinicopathological correlations were analyzed. RESULTS: All the 27 collected LTGCT cases were located in the small joints of patients' hands. Cases with solitary LGTCTs constituted 55.6% (n = 15), while 44.4% (n = 12) had multiple LTGCTs related to one affected site/case (e.g., multiple tumors in one finger). PPARγ was expressed in the cytoplasm of mononuclear and multinucleated tumor cells and foamy histiocytes, while P53 expression was mainly in mononuclear cells' nuclei. PPARγ significantly correlated with P53 expression (r = 0.9 and P = 0.000). PPARγ (r = 0.4 and P = 0.02) and P53 (r = 0.5 and P = 0.01) were positively correlated with tumor size. Only P53 expression was positively correlated with tumor multiplicity (r = 0.4 and P = 0.03). Using the receiver operating characteristic curve test, the P53 cutoff score detecting the multiplicity of TGCTs was ≥20.5%, with a 75% sensitivity and 80% specificity. CONCLUSION: PPARγ and P53 have a significant role in LTGCT growth, while P53 plays a role in tumor multiplicity. They can be possible targets in LTGCTs unfit for excision.

Reprogramming Glioblastoma Cells into Non-Cancerous Neuronal Cells as a Novel Anti-Cancer Strategy.

Glioblastoma Multiforme (GBM) is an aggressive brain tumor with a high mortality rate. Direct reprogramming of glial cells to different cell lineages, such as induced neural stem cells (iNSCs) and induced neurons (iNeurons), provides genetic tools to manipulate a cell's fate as a potential therapy for neurological diseases. NeuroD1 (ND1) is a master transcriptional factor for neurogenesis and it promotes neuronal differentiation. In the present study, we tested the hypothesis that the expression of ND1 in GBM cells can force them to differentiate toward post-mitotic neurons and halt GBM tumor progression. In cultured human GBM cell lines, including LN229, U87, and U373 as temozolomide (TMZ)-sensitive and T98G as TMZ-resistant cells, the neuronal lineage conversion was induced by an adeno-associated virus (AAV) package carrying ND1. Twenty-one days after AAV-ND1 transduction, ND1-expressing cells displayed neuronal markers MAP2, TUJ1, and NeuN. The ND1-induced transdifferentiation was regulated by Wnt signaling and markedly enhanced under a hypoxic condition (2% O2 vs. 21% O2). ND1-expressing GBM cultures had fewer BrdU-positive proliferating cells compared to vector control cultures. Increased cell death was visualized by TUNEL staining, and reduced migrative activity was demonstrated in the wound-healing test after ND1 reprogramming in both TMZ-sensitive and -resistant GBM cells. In a striking contrast to cancer cells, converted cells expressed the anti-tumor gene p53. In an orthotopical GBM mouse model, AAV-ND1-reprogrammed U373 cells were transplanted into the fornix of the cyclosporine-immunocompromised C57BL/6 mouse brain. Compared to control GBM cell-formed tumors, cells from ND1-reprogrammed cultures formed smaller tumors and expressed neuronal markers such as TUJ1 in the brain. Thus, reprogramming using a single-factor ND1 overcame drug resistance, converting malignant cells of heterogeneous GBM cells to normal neuron-like cells in vitro and in vivo. These novel observations warrant further research using patient-derived GBM cells and patient-derived xenograft (PDX) models as a potentially effective treatment for a deadly brain cancer and likely other astrocytoma tumors.