Tumor-Associated Antigen xCT and Mutant-p53 as Molecular Targets for New Combinatorial Antitumor Strategies

The cystine/glutamate antiporter xCT is a tumor-associated antigen that has been newly identified in many cancer types. By participating in glutathione biosynthesis, xCT protects cancer cells from oxidative stress conditions and ferroptosis, and contributes to metabolic reprogramming, thus promoting tumor progression and chemoresistance. Moreover, xCT is overexpressed in cancer stem cells. These features render xCT a promising target for cancer therapy, as has been widely reported in the literature and in our work on its immunotargeting. Interestingly, studies on the TP53 gene have revealed that both wild-type and mutant p53 induce the post-transcriptional down modulation of xCT, contributing to ferroptosis. Moreover, APR-246, a small molecule drug that can restore wild-type p53 function in cancer cells, has been described as an indirect modulator of xCT expression in tumors with mutant p53 accumulation, and is thus a promising drug to use in combination with xCT inhibition. This review summarizes the current knowledge of xCT and its regulation by p53, with a focus on the crosstalk of these two molecules in ferroptosis, and also considers some possible combinatorial strategies that can make use of APR-246 treatment in combination with anti-xCT immunotargeting.

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The Function of the Mutant p53-R175H in Cancer

Cancers ◽

10.3390/cancers13164088 ◽

2021 ◽

Vol 13 (16) ◽

pp. 4088

Author(s):

Yen-Ting Chiang ◽

Yi-Chung Chien ◽

Yu-Heng Lin ◽

Hui-Hsuan Wu ◽

Dung-Fang Lee ◽

...

Keyword(s):

Cancer Cells ◽

Gene Mutations ◽

Metabolic Reprogramming ◽

Cancer Development ◽

Mutant P53 ◽

Missense Mutations ◽

Wild Type ◽

Downstream Signaling ◽

Hotspot Mutations ◽

Wild Type P53

Wild-type p53 is known as “the guardian of the genome” because of its function of inducing DNA repair, cell-cycle arrest, and apoptosis, preventing the accumulation of gene mutations. TP53 is highly mutated in cancer cells and most TP53 hotspot mutations are missense mutations. Mutant p53 proteins, encoded by these hotspot mutations, lose canonical wild-type p53 functions and gain functions that promote cancer development, including promoting cancer cell proliferation, migration, invasion, initiation, metabolic reprogramming, angiogenesis, and conferring drug resistance to cancer cells. Among these hotspot mutations, p53-R175H has the highest occurrence. Although losing the transactivating function of the wild-type p53 and prone to aggregation, p53-R175H gains oncogenic functions by interacting with many proteins. In this review, we summarize the gain of functions of p53-R175H in different cancer types, the interacting proteins of p53-R175H, and the downstream signaling pathways affected by p53-R175H to depict a comprehensive role of p53-R175H in cancer development. We also summarize treatments that target p53-R175H, including reactivating p53-R175H with small molecules that can bind to p53-R175H and alter it into a wild-type-like structure, promoting the degradation of p53-R175H by targeting heat-shock proteins that maintain the stability of p53-R175H, and developing immunotherapies that target the p53-R175H–HLA complex presented by tumor cells.

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Mutant p53 as an Antigen in Cancer Immunotherapy

International Journal of Molecular Sciences ◽

10.3390/ijms21114087 ◽

2020 ◽

Vol 21 (11) ◽

pp. 4087 ◽

Cited By ~ 1

Author(s):

Navid Sobhani ◽

Alberto D’Angelo ◽

Xu Wang ◽

Ken H. Young ◽

Daniele Generali ◽

...

Keyword(s):

Cancer Cells ◽

Cancer Patients ◽

Current Knowledge ◽

Adaptive Immune Response ◽

Mutant P53 ◽

Wild Type ◽

P53 Antibodies ◽

Wild Type P53

The p53 tumor suppressor plays a pivotal role in cancer and infectious disease. Many oncology treatments are now calling on immunotherapy approaches, and scores of studies have investigated the role of p53 antibodies in cancer diagnosis and therapy. This review summarizes the current knowledge from the preliminary evidence that suggests a potential role of p53 as an antigen in the adaptive immune response and as a key monitor of the innate immune system, thereby speculating on the idea that mutant p53 antigens serve as a druggable targets in immunotherapy. Except in a few cases, the vast majority of published work on p53 antibodies in cancer patients use wild-type p53 as the antigen to detect these antibodies and it is unclear whether they can recognize p53 mutants carried by cancer patients at all. We envision that an antibody targeting a specific mutant p53 will be effective therapeutically against a cancer carrying the exact same mutant p53. To corroborate such a possibility, a recent study showed that a T cell receptor-like (TCLR) antibody, initially made for a wild-type antigen, was capable of discriminating between mutant p53 and wild-type p53, specifically killing more cancer cells expressing mutant p53 than wild-type p53 in vitro and inhibiting the tumour growth of mice injected with mutant p53 cancer cells than mice with wild-type p53 cancer cells. Thus, novel antibodies targeting mutant p53, but not the wild-type isoform, should be pursued in preclinical and clinical studies.

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Antitumor Effects of PRIMA-1 and PRIMA-1Met (APR246) in Hematological Malignancies: Still a Mutant P53-Dependent Affair?

Cells ◽

10.3390/cells10010098 ◽

2021 ◽

Vol 10 (1) ◽

pp. 98

Author(s):

Paola Menichini ◽

Paola Monti ◽

Andrea Speciale ◽

Giovanna Cutrona ◽

Serena Matis ◽

...

Keyword(s):

Hematological Malignancies ◽

Cell Metabolism ◽

Therapy Response ◽

Tp53 Gene ◽

Suppressor Gene ◽

Lower Percentage ◽

Mutant P53 ◽

Wild Type ◽

Antitumor Effects ◽

Tp53 Tumor Suppressor Gene

Because of its role in the regulation of the cell cycle, DNA damage response, apoptosis, DNA repair, cell migration, autophagy, and cell metabolism, the TP53 tumor suppressor gene is a key player for cellular homeostasis. TP53 gene is mutated in more than 50% of human cancers, although its overall dysfunction may be even more frequent. TP53 mutations are detected in a lower percentage of hematological malignancies compared to solid tumors, but their frequency generally increases with disease progression, generating adverse effects such as resistance to chemotherapy. Due to the crucial role of P53 in therapy response, several molecules have been developed to re-establish the wild-type P53 function to mutant P53. PRIMA-1 and its methylated form PRIMA-1Met (also named APR246) are capable of restoring the wild-type conformation to mutant P53 and inducing apoptosis in cancer cells; however, they also possess mutant P53-independent properties. This review presents the activities of PRIMA-1 and PRIMA-1Met/APR246 and describes their potential use in hematological malignancies.

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Suberoylanilide hydroxamic acid enhances the radiosensitivity of lung cancer cells through acetylated wild-type and mutant p53-dependent modulation of mitochondrial apoptosis

Journal of International Medical Research ◽

10.1177/0300060520981545 ◽

2021 ◽

Vol 49 (2) ◽

pp. 030006052098154

Author(s):

Kan Wu ◽

Xueqin Chen ◽

Xufeng Chen ◽

Shirong Zhang ◽

Yasi Xu ◽

...

Keyword(s):

Lung Cancer ◽

Cancer Cells ◽

Hydroxamic Acid ◽

Site Directed Mutagenesis ◽

Lung Cancer Cells ◽

Mutant P53 ◽

Suberoylanilide Hydroxamic Acid ◽

Mitochondrial Apoptosis ◽

Wild Type ◽

Clonogenic Cell

Objective Suberoylanilide hydroxamic acid (SAHA), a histone deacetylase inhibitor, has shown potential as a candidate radiosensitizer for many types of cancers. This study aimed to explore the radiosensitization mechanism of SAHA in lung cancer cells. Methods Mutations in p53 were generated by site-directed mutagenesis using polymerase chain reaction. Transfection was performed to generate H1299 cells carrying wild-type or mutant p53. The radiosensitizing enhancement ratio was determined by clonogenic assays. Mitochondrial apoptosis was detected using JC-1 staining and flow cytometry analysis. Results Our results showed that SAHA induced radiosensitization in H1299 cells expressing wild-type p53, p53R175H or p53P223L, but this enhanced clonogenic cell death was not observed in parental H1299 (p53-null) cells or H1299 cells expressing p53 with K120R, A161T and V274R mutations. In SAHA-sensitized cells, mitochondrial apoptosis was induced following exposure to irradiation. Additionally, we observed that a secondary mutation at K120 (K120R) could eliminate p53-mediated radiosensitization and mitochondrial apoptosis. Conclusions The results of this study suggest that wild-type and specific mutant forms of p53 mediate SAHA-induced radiosensitization by regulating mitochondrial apoptosis, and the stabilization of K120 acetylation by SAHA is the molecular basis contributing to radiosensitization in lung cancer cells.

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Limonene and BEZ 235 inhibits growth of COLO-320 and HCT-116 colon cancer cells

International Journal of Drug Delivery ◽

10.5138/09750215.1919 ◽

2016 ◽

Vol 8 (3) ◽

pp. 89 ◽

Cited By ~ 2

Author(s):

Raja Ratna Reddy Yakkanti ◽

P Chandra Sekhar ◽

K Bharath Nandhan Reddy ◽

S Ramamoorthy ◽

S Ranga Suresh ◽

...

Keyword(s):

Colon Cancer ◽

Cancer Cells ◽

Colon Cancer Cells ◽

Wild Type ◽

Anticancer Effects ◽

Clonogenic Potential ◽

Hct 116 ◽

Cancer Types ◽

Hct 116 Cells ◽

Preclinical And Clinical Studies

<p>D-Limonene is a dietary monoterpene with significant anticancer activity against many cancer types in preclinical and clinical studies. The study is designed to investigate synergistic anticancer effects of limonene and BEZ235 combination in COLO-320 and HCT-116 colon cancer cells. Cells were treated with both the drugs alone and in combination and the effects on cell viability; cell migration and clonogenic potential were examined. Results show that both drugs exhibited dose and time dependant cytotoxicity on the cell lines tested. CompuSyn analysis of the drug combination effects revealed the strong synergistic interaction of the combination. Our results also indicate that COLO-320 cells were more sensitive for anticancer effects of the drugs than HCT-116 cells. The presence of Ras and PI3K mutations in HCT-116 cells could possibly be one of the main reasons for the observed outcome as compared to the wild type expressions of them in COLO-320 cells.</p>

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The Janus Face of p53-Targeting Ubiquitin Ligases

Cells ◽

10.3390/cells9071656 ◽

2020 ◽

Vol 9 (7) ◽

pp. 1656 ◽

Cited By ~ 3

Author(s):

Qian Hao ◽

Yajie Chen ◽

Xiang Zhou

Keyword(s):

Cancer Progression ◽

Ubiquitin Ligases ◽

Tp53 Gene ◽

Mutant P53 ◽

E3 Ubiquitin Ligases ◽

Tumor Suppressor P53 ◽

Wild Type ◽

Cell Growth Arrest ◽

Cancer Cell Survival ◽

P53 Status

The tumor suppressor p53 prevents tumorigenesis and cancer progression by maintaining genomic stability and inducing cell growth arrest and apoptosis. Because of the extremely detrimental nature of wild-type p53, cancer cells usually mutate the TP53 gene in favor of their survival and propagation. Some of the mutant p53 proteins not only lose the wild-type activity, but also acquire oncogenic function, namely “gain-of-function”, to promote cancer development. Growing evidence has revealed that various E3 ubiquitin ligases are able to target both wild-type and mutant p53 for degradation or inactivation, and thus play divergent roles leading to cancer cell survival or death in the context of different p53 status. In this essay, we reviewed the recent progress in our understanding of the p53-targeting E3 ubiquitin ligases, and discussed the potential clinical implications of these E3 ubiquitin ligases in cancer therapy.

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The Warburg effect: 80 years on

Biochemical Society Transactions ◽

10.1042/bst20160094 ◽

2016 ◽

Vol 44 (5) ◽

pp. 1499-1505 ◽

Cited By ~ 155

Author(s):

Michelle Potter ◽

Emma Newport ◽

Karl J. Morten

Keyword(s):

Cancer Cells ◽

High Glucose ◽

Warburg Effect ◽

Energy Requirement ◽

Glucose Consumption ◽

High Energy ◽

Metabolic Reprogramming ◽

Normal Cells ◽

Cancer Types ◽

The Warburg Effect

Influential research by Warburg and Cori in the 1920s ignited interest in how cancer cells' energy generation is different from that of normal cells. They observed high glucose consumption and large amounts of lactate excretion from cancer cells compared with normal cells, which oxidised glucose using mitochondria. It was therefore assumed that cancer cells were generating energy using glycolysis rather than mitochondrial oxidative phosphorylation, and that the mitochondria were dysfunctional. Advances in research techniques since then have shown the mitochondria in cancer cells to be functional across a range of tumour types. However, different tumour populations have different bioenergetic alterations in order to meet their high energy requirement; the Warburg effect is not consistent across all cancer types. This review will discuss the metabolic reprogramming of cancer, possible explanations for the high glucose consumption in cancer cells observed by Warburg, and suggest key experimental practices we should consider when studying the metabolism of cancer.

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Induction of wild-type p53 activity in human cancer cells by ribozymes that repair mutant p53 transcripts

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.150104097 ◽

2000 ◽

Vol 97 (15) ◽

pp. 8490-8494 ◽

Cited By ~ 87

Author(s):

T. Watanabe ◽

B. A. Sullenger

Keyword(s):

Cancer Cells ◽

Human Cancer ◽

Mutant P53 ◽

Wild Type ◽

Human Cancer Cells ◽

Wild Type P53

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Deficient or R273H and R248W Mutations of p53 Promote Chemoresistance to 5-FU via TCF21/CD44 Axis-Mediated Enhanced Stemness in Colorectal Carcinoma

Frontiers in Cell and Developmental Biology ◽

10.3389/fcell.2021.788331 ◽

2022 ◽

Vol 9 ◽

Author(s):

Xiaolei Gao ◽

Xuan Zheng ◽

Yixin Zhang ◽

Liying Dong ◽

Liangjie Sun ◽

...

Keyword(s):

Colorectal Carcinoma ◽

Cancer Cells ◽

Signaling Pathway ◽

Cell Lines ◽

Hct116 Cell ◽

Luciferase Reporter Assay ◽

Luciferase Reporter ◽

Mutant P53 ◽

Reporter Assay ◽

Wild Type

Background: p53 mutations are highly frequent in various human cancers and are reported to contribute to tumor malignance and chemoresistance. In this study, we explored the mechanism by which mutant p53 promotes carcinogenesis and chemoresistance and provided novel insights into cancer therapy.Materials and methods: A total of 409 patients with colorectal carcinoma from TCGA database were subdivided into two groups according to the p53 status, namely, mutant p53 and wild-type p53, following with GSEA analysis. The differences of the clinicopathologic index were also analyzed. Two HCT116 cell lines containing hot spots at codons R273H and R248W of p53 were constructed based on HCT116 with knockout p53, respectively. Cell viability, mobility, clonogenesis, and stemness were detected by CCK8, transwell migration and invasion, colonogenic, and sphere formation assays. Resistance to 5-FU was examined by live-dead staining and flow cytometry. qPCR, Western blot, and luciferase reporter assay were performed to identify that deficient or mutant p53 promoted chemoresistance of the colorectal carcinoma cell line HCT116 through the TCF21/CD44 signaling pathway, with the following rescue assays by overexpression of TCF21 and knockdown of CD44.Results: Patients with recurrence harbor a higher frequency of mutant p53 than those without recurrence (p < 0.05). The mutant p53 group developed a larger tumor than the wild-type one. GSEA analysis showed that oncogenic signatures were enriched in the mutant p53 group. Extracellular assays showed that cancer cells with deficient or mutant p53 (R273H and R248W, respectively) promoted colon cancer cell growth, migration, invasion, and stemness. The mutant cancer cells were also observed to be significantly resistant to 5-FU. Xenografts also confirmed that HCT116 cells harboring deficient or mutant p53 promoted cancer growth and 5-FU tolerance. Luciferase reporter assay showed that deficient or mutant p53 R237H and R248W endowed cancer cells with chemoresistance by activating CD44 via repressing the nuclear transcription factor TCF21 expression. Overexpression of TCF21 or knockdown of CD44 could rescue the sensitivity to 5-FU in deficient and mutant p53 HCT116 cell lines.Conclusion: Our results, for the first time, reveal a novel deficient or mutant p53/TCF21/CD44 signaling pathway which promotes chemoresistance in colorectal carcinoma. The axis could be an effective therapeutic strategy against deficient- or mutant p53-driven chemoresistance.

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