p53 Signaling on Microenvironment and Its Contribution to Tissue Chemoresistance

Trp53 Deletion Promotes Exacerbated Colitis, Facilitates Lgr5+ Cancer Stem Cell Expansion, and Fuels Tumorigenesis in AOM/DSS-Induced Colorectal Cancer

Colorectal cancer CRC remains one of the leading causes of cancer-related deaths worldwide, with chronic intestinal inflammation identified as a major risk factor. Notably, the tumor suppressor TP53 undergoes mutation at higher rates and earlier stages during human inflammation-driven colon tumorigenesis than in sporadic cases. We investigated whether deleting Trp53 affects inflammation-induced tumor growth and the expression of Lgr5+ cancer stem cells in mice. We examined azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced colon tumorigenesis in wild-type Trp53 (+/+), heterozygous (+/-), and knockout (-/-) mice. Trp53-/- mice showed increased sensitivity to DSS colitis and earlier accelerated tumorigenesis with 100% incidence. All groups could develop invasive tumors, but knockouts displayed the most aggressive features. Unlike wild-type CRC, knockouts selectively showed increased populations of Lgr5+ colon cancer stem-like cells. Trp53 loss also boosted laminin, possibly facilitating the disruption of the tumor border. This study highlights how Trp53 deletion promotes the perfect storm of inflammation and stemness, driving colon cancer progression. Trp53 deletion dramatically shortened AOM/DSS latency and improved tumor induction efficiency, offering an excellent inflammation-driven CRC model.

P53/NANOG balance; the leading switch between poorly to well differentiated status in liver cancer cells

Enforcing a well-differentiated state on cells requires tumor suppressor p53 activation as a key player in apoptosis induction and well differentiation. In addition, recent investigations showed a significant correlation between poorly differentiated status and higher expression of NANOG. Inducing the expression of NANOG and decreasing p53 level switch the status of liver cancer cells from well differentiated to poorly status. In this review, we highlighted p53 and NANOG cross-talk in hepatocellular carcinoma (HCC) which is regulated through mitophagy and makes it a novel molecular target to attenuate cancerous phenotype in the management of this tumor.

Genetic mechanisms underlying tumor microenvironment composition and function in diffuse large B-cell lymphoma

ABSTRACT

Cells in the tumor microenvironment (TME) of diffuse large B-cell lymphoma (DLBCL) show enormous diversity and plasticity, with functions that can range from tumor inhibitory to tumor supportive. The patient's age, immune status, and DLBCL treatments are factors that contribute to the shaping of this TME, but evidence suggests that genetic factors, arising principally in lymphoma cells themselves, are among the most important. Here, we review the current understanding of the role of these genetic drivers of DLBCL in establishing and modulating the lymphoma microenvironment. A better comprehension of the relationship between lymphoma genetic factors and TME biology should lead to better therapeutic interventions, especially immunotherapies.

DCAF13 inhibits the p53 signaling pathway by promoting p53 ubiquitination modification in lung adenocarcinoma

BACKGROUND

Lung cancer is a malignant tumor with the highest mortality worldwide. Abnormalities in the ubiquitin proteasome system are considered to be contributed to lung cancer progression with deleterious effects. DDB1 and CUL4 associated factor 13 (DCAF13) is a substrate receptor of the E3 ubiquitin ligase CRL4, but its role in lung cancer remains unknown. In this study, we aimed to investigate the regulatory mechanisms of DCAF13 in lung adenocarcinoma (LUAD).

METHODS

So as to investigate the effect of DCAF13 on lung adenocarcinoma cell function using in vivo and in vitro. Mechanistically, we have identified the downstream targets of DCAF13 by using RNA-sequencing, as well as ubiquitination assays, co-immunoprecipitation, immunofluorescence, immunohistochemistry and chromatin immunoprecipitation - qPCR experiments.

RESULTS

Our findings reveal that DCAF13 is a carcinogenic factor in LUAD, as it is highly expressed and negatively correlated with clinical outcomes in LUAD patients. Through RNA-sequencing, it has been shown that DCAF13 negatively regulates the p53 signaling pathway and inhibits p53 downstream targets including p21, BAX, FAS, and PIDD1. We also demonstrate that DCAF13 can bind to p53 protein, leading to K48-linked ubiquitination and degradation of p53. Functionally, we have shown that DCAF13 knockdown inhibits cell proliferation and migration. Our results highlight the significant role of DCAF13 in promoting LUAD progression by inhibiting p53 protein stabilization and the p53 signaling pathway. Furthermore, our findings suggest that high DCAF13 expression is a poor prognostic indicator in LUAD, and DCAF13 may be a potential therapeutic target for treating with this aggressive cancer.

CONCLUSIONS

The DCAF13 as a novel negative regulator of p53 to promote LUAD progression via facilitating p53 ubiquitination and degradation, suggesting that DCAF13 might be a novel biomarker and therapeutical target for LUAD.

Trabectedin induces ferroptosis via regulation of HIF-1α/IRP1/TFR1 and Keap1/Nrf2/GPX4 axis in non-small cell lung cancer cells

BACKGROUND AND OBJECTIVES

Non-small cell lung cancer (NSCLC) is a global health concern. NSCLC treatment outcomes are generally poor due to treatment resistance or toxicity. Ferroptosis is a novel cell death triggered by iron accumulation, reactive oxygen species (ROS), and lipid peroxidation. Ferroptosis may kill cancer cells, particularly those resistant to apoptosis.

MATERIALS AND METHODS

The Cell Counting Kit-8 assay assessed NSCLC cell viability after trabectedin treatment. Flow cytometry with Annexin V-FITC staining evaluated cell death. ROS, iron, lipid peroxidation, and GSH levels were measured using commercial kits. qRT-PCR and western blots evaluated messenger RNA and protein levels. Proteins were inhibited using short interfering RNA transfection and specific inhibitors.

RESULTS

Trabectedin was cytotoxic to NSCLC cells regardless of p53 status. Trabectedin upregulated iron, ROS, and lipid peroxidation in NSCLC cells, causing ferroptosis. Trabectedin increases iron and ROS levels by upregulating transferrin receptor 1 and the HIF-1/IRP1 axis. In NSCLC cells, trabectedin suppresses glutathione peroxidase 4, followed by the Keap1/Nrf2 axis.

CONCLUSIONS

Our findings imply that trabectedin may treat NSCLC effectively.

p53 Modulates Radiosensitivity in Head and Neck Cancers-From Classic to Future Horizons

p53, initially considered a tumor suppressor, has been the subject of research related to cancer treatment resistance in the last 30 years. The unfavorable response to multimodal therapy and the higher recurrence rate, despite an aggressive approach, make HNSCC a research topic of interest for improving therapeutic outcomes, even if it is only the sixth most common malignancy worldwide. New advances in molecular biology and genetics include the involvement of miRNA in the control of the p53 pathway, the understanding of mechanisms such as gain/loss of function, and the development of different methods to restore p53 function, especially for HPV-negative cases. The different ratio between mutant p53 status in the primary tumor and distant metastasis originating HNSCC may serve to select the best therapeutic target for activating an abscopal effect by radiotherapy as a "booster" of the immune system. P53 may also be a key player in choosing radiotherapy fractionation regimens. Targeting any pathway involving p53, including tumor metabolism, in particular the Warburg effect, could modulate the radiosensitivity and chemo-sensitivity of head and neck cancers.

The Underestimated Role of the p53 Pathway in Renal Cancer

The TP53 tumor suppressor gene is known as the guardian of the genome, playing a pivotal role in controlling genome integrity, and its functions are lost in more than 50% of human tumors due to somatic mutations. This percentage rises to 90% if mutations and alterations in the genes that code for regulators of p53 stability and activity are taken into account. Renal cell carcinoma (RCC) is a clear example of cancer that despite having a wild-type p53 shows poor prognosis because of the high rate of resistance to radiotherapy or chemotherapy, which leads to recurrence, metastasis and death. Remarkably, the fact that p53 is poorly mutated does not mean that it is functionally active, and increasing experimental evidences have demonstrated this. Therefore, RCC represents an extraordinary example of the importance of p53 pathway alterations in therapy resistance. The search for novel molecular biomarkers involved in the pathways that regulate altered p53 in RCC is mandatory for improving early diagnosis, evaluating the prognosis and developing novel potential therapeutic targets for better RCC treatment.

Li–Fraumeni Syndrome: Mutation of TP53 Is a Biomarker of Hereditary Predisposition to Tumor: New Insights and Advances in the Treatment

Simple Summary

Li–Fraumeni Syndrome (LFS) is a rare tumor predisposition syndrome in which the tumor suppressor TP53 gene is mutated in the germ cell population. LFS patients develop a broad spectrum of cancers in their lifetime. The risk to develop these tumors is not decreased by any type of treatment and if the analysis of the TP53 mutational status in the family members was not possible, tumors are often diagnosed in already advanced stages. This review aims to report the evidence for novel mechanisms of tumor onset related to germline TP53 mutations and possible treatments.

Abstract

Li–Fraumeni syndrome (LFS) is a rare familial tumor predisposition syndrome with autosomal dominant inheritance, involving germline mutations of the TP53 tumor suppressor gene. The most frequent tumors that arise in patients under the age of 45 are osteosarcomas, soft-tissue sarcomas, breast tumors in young women, leukemias/lymphomas, brain tumors, and tumors of the adrenal cortex. To date, no other gene mutations have been associated with LFS. The diagnosis is usually confirmed by genetic testing for the identification of TP53 mutations; therefore, these mutations are considered the biomarkers associated with the tumor spectrum of LFS. Here, we aim to review novel molecular mechanisms involved in the oncogenic functions of mutant p53 in LFS and to discuss recent new diagnostic and therapeutic approaches exploiting TP53 mutations as biomarkers and druggable targets.

Bioactivity and Development of Small Non-Platinum Metal-Based Chemotherapeutics

Countless expectations converge in the multidisciplinary endeavour for the search and development of effective and safe drugs in fighting cancer. Although they still embody a minority of the pharmacological agents currently in clinical use, metal-based complexes have great yet unexplored potential, which probably hides forthcoming anticancer drugs. Following the historical success of cisplatin and congeners, but also taking advantage of conventional chemotherapy limitations that emerged with applications in the clinic, the design and development of non-platinum metal-based chemotherapeutics, either as drugs or prodrugs, represents a rapidly evolving field wherein candidate compounds can be fine-tuned to access interactions with druggable biological targets. Moving in this direction, over the last few decades platinum family metals, e.g., ruthenium and palladium, have been largely proposed. Indeed, transition metals and molecular platforms where they originate are endowed with unique chemical and biological features based on, but not limited to, redox activity and coordination geometries, as well as ligand selection (including their inherent reactivity and bioactivity). Herein, current applications and progress in metal-based chemoth are reviewed. Converging on the recent literature, new attractive chemotherapeutics based on transition metals other than platinum—and their bioactivity and mechanisms of action—are examined and discussed. A special focus is committed to anticancer agents based on ruthenium, palladium, rhodium, and iridium, but also to gold derivatives, for which more experimental data are nowadays available. Next to platinum-based agents, ruthenium-based candidate drugs were the first to reach the stage of clinical evaluation in humans, opening new scenarios for the development of alternative chemotherapeutic options to treat cancer.