Gain-of-function of mutant p53: mutant p53 enhances cancer progression by inhibiting KLF17 expression in invasive breast carcinoma cells

Functional Enrichment Analysis of Tumor Microenvironment-Driven Molecular Alterations That Facilitate Epithelial-to-Mesenchymal Transition and Distant Metastasis

Nowadays, hepatocellular carcinoma (HCC) is the second leading cause of cancer deaths, and identifying the effective factors in causing this disease can play an important role in its prevention and treatment. Tumors provide effective agents for invasion and metastasis to other organs by establishing appropriate communication between cancer cells and the microenvironment. Epithelial-to-mesenchymal transition (EMT) can be mentioned as one of the effective phenomena in tumor invasion and metastasis. Several factors are involved in inducing this phenomenon in the tumor microenvironment, which helps the tumor survive and migrate to other places. It can be effective to identify these factors in the use of appropriate treatment strategies and greater patient survival. This study investigated the molecular differences between tumor border cells and tumor core cells or internal tumor cells in HCC for specific EMT genes. Expression of NOTCH1, ID1, and LST1 genes showed a significant increase at the HCC tumor border. Targeting these genes can be considered as a useful therapeutic strategy to prevent distant metastasis in HCC patients.

First case of endometrial cancer after yolk sac tumor in a patient with Li-Fraumeni syndrome

BACKGROUND

Li-Fraumeni syndrome (LFS) is a rare autosomal dominant disease with high penetrance caused by a germline variant of TP53 gene. We report the first case of endometrial cancer after yolk sac tumor with LFS.

CASE PRESENTATION

The presented female patient underwent right adnexectomy at age 23 because of a yolk sac tumor of the ovary. At the age of 27, the patient was diagnosed with endometrial adenocarcinoma, received cytoreductive surgery and chemotherapy. Given that her personal cancer history along with a strong family history of cancer, her father passing away from lung cancer at age 48 and her grandmother dying of ovarian cancer at age 50, the patient was referred for genetic counseling and testing. Genetic screening revealed a heterozygous pathogenic TP53 c.844C > T, p.( R282 W) with NM_000546.5 variant, a class 5 (C5) variant. This is the first reported case of a yolk sac tumor accompanied by subsequent endometrial cancer that is associated with LFS.

CONCLUSIONS

We reported a first case of an endometrial cancer after yolk sac tumor patient with a tumor family history of harboring the germline TP53 pathogenic variation which expanded types of tumor that can be presented in patients with LFS. This case highlights the importance of genetic testing for patients with malignant tumors, as well as patients with a family history of malignant tumors. And our case highlights the necessity of screening for gynecologic tumor in LFS patients.

Different impacts of TP53 mutations on cell cycle-related gene expression among cancer types

Functional properties caused by TP53 mutations are involved in cancer development and progression. Although most of the mutations lose normal p53 functions, some of them, gain-of-function (GOF) mutations, exhibiting novel oncogenic functions. No reports have analyzed the impact of TP53 mutations on the gene expression profile of the p53 signaling pathway across cancer types. This study is a cross-cancer type analysis of the effects of TP53 mutations on gene expression. A hierarchical cluster analysis of the expression profile of the p53 signaling pathway classified 21 cancer types into two clusters (A1 and A2). Changes in the expression of cell cycle-related genes and MKI67 by TP53 mutations were greater in cluster A1 than in cluster A2. There was no distinct difference in the effects between GOF and non-GOF mutations on the gene expression profile of the p53 signaling pathway.

Methods for the Discovery and Identification of Small Molecules Targeting Oxidative Stress-Related Protein–Protein Interactions: An Update

The oxidative stress response pathway is one of the hotspots of current pharmaceutical research. Many proteins involved in these pathways work through protein–protein interactions (PPIs). Hence, targeting PPI to develop drugs for an oxidative stress response is a promising strategy. In recent years, small molecules targeting protein–protein interactions (PPIs), which provide efficient methods for drug discovery, are being investigated by an increasing number of studies. However, unlike the enzyme–ligand binding mode, PPIs usually exhibit large and dynamic binding interfaces, which raise additional challenges for the discovery and optimization of small molecules and for the biochemical techniques used to screen compounds and study structure–activity relationships (SARs). Currently, multiple types of PPIs have been clustered into different classes, which make it difficult to design stationary methods for small molecules. Deficient experimental methods are plaguing medicinal chemists and are becoming a major challenge in the discovery of PPI inhibitors. In this review, we present current methods that are specifically used in the discovery and identification of small molecules that target oxidative stress-related PPIs, including proximity-based, affinity-based, competition-based, structure-guided, and function-based methods. Our aim is to introduce feasible methods and their characteristics that are implemented in the discovery of small molecules for different types of PPIs. For each of these methods, we highlight successful examples of PPI inhibitors associated with oxidative stress to illustrate the strategies and provide insights for further design.

Applications of Recombinant Adenovirus-p53 Gene Therapy for Cancers in the Clinic in China

Suppression of TP53 function is nearly ubiquitous in human cancers, and a significant fraction of cancers have mutations in the TP53 gene itself. Therefore, the wild-type TP53 gene has become an important target gene for transformation research of cancer gene therapy. In 2003, the first anti-tumor gene therapy drug rAd-p53 (recombinant human p53 adenovirus), trade name Gendicine™, was approved by the China Food and Drug Administration (CFDA) for treatment of head and neck squamous cell carcinoma (HNSCC) in combination with radiotherapy. The recombinant human TP53 gene is delivered into cancer cells by an adenovirus vector constructed to express the functional p53 protein. Although the only currently approved used of Gendicine is in combination with radiotherapy for treatment of HNSCC, clinical studies have been carried out for more than 20 other applications of Gendicine in treating cancer, including treatment of advanced lung cancer, advanced liver cancer, malignant gynecological tumors, and soft tissue sarcomas. Currently more than 30,000 patients have been treated with Gendicine. This review provides an overview of the clinical applications of Gendicine in China. We summarize a total of 48 studies with 2,561 patients with solid tumors, including 34 controlled clinical studies and 14 open clinical studies, i.e., clinical studies without a control group. There are 11 studies for head and neck cancer, 10 for liver cancer, 6 for malignant gynecological tumors, 4 for non-small cell lung cancer, 4 for soft tissue sarcoma, 4 for malignant effusion, 2 for gastrointestinal tumors, and 7 for other types of cancer. In all the reported clinical studies, the most common side effect was self-limited fever. Intratumoral injection and intra-arterial infusion were the most common routes of administration. Overall, Gendicine combined with chemotherapy, radiotherapy, or other conventional treatment regimens demonstrated significantly higher response rates compared to standard therapies alone. Some of the published studies also showed that Gendicine combination regimens demonstrated longer progression-free survival times than conventional treatments alone. To date, Gendicine has been clinically used in China for treatment of cancers other than HNSCC for more than ten years, mainly for patients with advanced or unresectable malignant tumors. However, the establishment of standard treatment regimens using TP53 gene therapy is still needed in order to advance its use in clinical practice.

The Genomic Response to TGF-β1 Dictates Failed Repair and Progression of Fibrotic Disease in the Obstructed Kidney

Tubulointerstitial fibrosis is a common and diagnostic hallmark of a spectrum of chronic renal disorders. While the etiology varies as to the causative nature of the underlying pathology, persistent TGF-β1 signaling drives the relentless progression of renal fibrotic disease. TGF-β1 orchestrates the multifaceted program of kidney fibrogenesis involving proximal tubular dysfunction, failed epithelial recovery or re-differentiation, capillary collapse and subsequent interstitial fibrosis eventually leading to chronic and ultimately end-stage disease. An increasing complement of non-canonical elements function as co-factors in TGF-β1 signaling. p53 is a particularly prominent transcriptional co-regulator of several TGF-β1 fibrotic-response genes by complexing with TGF-β1 receptor-activated SMADs. This cooperative p53/TGF-β1 genomic cluster includes genes involved in cellular proliferative control, survival, apoptosis, senescence, and ECM remodeling. While the molecular basis for this co-dependency remains to be determined, a subset of TGF-β1-regulated genes possess both p53- and SMAD-binding motifs. Increases in p53 expression and phosphorylation, moreover, are evident in various forms of renal injury as well as kidney allograft rejection. Targeted reduction of p53 levels by pharmacologic and genetic approaches attenuates expression of the involved genes and mitigates the fibrotic response confirming a key role for p53 in renal disorders. This review focuses on mechanisms underlying TGF-β1-induced renal fibrosis largely in the context of ureteral obstruction, which mimics the pathophysiology of pediatric unilateral ureteropelvic junction obstruction, and the role of p53 as a transcriptional regulator within the TGF-β1 repertoire of fibrosis-promoting genes.

CYR61 as a potential biomarker for the preoperative identification of muscle-invasive bladder cancers

Background

The biological behaviors, clinical treatment, prognosis of non-muscle-invasive bladder cancers (NMIBCs) and muscle-invasive bladder cancers (MIBCs) are distinct. Accurate staging is pivotal in optimal therapy planning for bladder cancers (BCs). However, it is insufficient for urologists in preoperative determining whether the tumor has invaded within the muscularis propria through cystoscope and imaging methods (CT or MRI). Therefore, searching for ideal biomarkers from the tumor tissues and urine is important for identifying the MIBCs preoperatively.

Methods

Differentially expressed genes between NMIBCs and MIBCs were identified by microarray analysis and validated by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and immunohistochemical analysis. The correlation between cysteine-rich angiogenic inducer 61 (CYR61) expression and Kaplan-Meier test evaluated patients’ overall survival (OS). CYR61 protein levels were measured using enzyme-linked immunosorbent assay (ELISA) in preoperatively collected urine samples from BC patients. The receiver-operating characteristic (ROC) curve analyzed the diagnostic accuracy of uric CYR61. The siRNA mediated silencing of CYR61 in bladder carcinoma cells was performed using Lipofectamine 2000. Cell migration and invasion were assessed using wound healing and transwell assay, respectively.

Results

Differential gene expression analysis using microarray between 14 MIBCs and 16 NMIBCs human tumor samples revealed a significant increase (P<0.001) in the expression of CYR61 in MIBCs compared with NMIBCs. Higher expression of CYR61 in MIBCs was found in additional 54 tumor samples using qRT-PCR. Therefore, the overexpression of CYR61 in MIBCs could be used as a potential biomarker to distinguish between MIBCs and NMIBCs. ELISA detected elevated levels of CYR61 in the urine samples of MIBC patients (average 2.5-fold) compared with NMIBCs, with 72.7% sensitivity and 86.0% specificity to distinguish MIBCs from NMIBCs. Wound healing and transwell assays using CYR61-silenced carcinoma cells indicated the role of CYR61 in cell migration and invasion.

Conclusions

CYR61 expression is higher in MIBCs compared with NMIBCs and can serve as a promising biomarker for the preoperative diagnosis of MIBCs with prognostic value; however, multicentric prospective validation is essential for the further evaluation of CYR61.

Ring finger 20/ring finger 40/WW domain-containing adaptor with coiled-coil complex interacts with p53 to regulate gene transcription in DNA damage response

p53 is one of the most important tumor suppressor genes, and its primary function is to act as a transcriptional activator to control cell cycle arrest, DNA repair and cellular metabolism by recognizing and binding to specific DNA sequences. Defects in the ring finger (RNF)20/RNF40/WW domain-containing adaptor with coiled-coil (WAC) complex, one of the histone H2B ubiquitination E3 ligases, have been reported to be a key factor in oncogenesis, cancer cell migration and invasion. Histone H2B mono-ubiquitination has been demonstrated to be essential for maintaining the functionality of the p53 tumor suppressor protein. The aim of the present study was to identify any sites in the p53 DNA-binding domain (DBD) specific to the RNF20/RNF40/WAC complex that may be involved in the gene regulation in DNA damage response. The results demonstrated that p53 and the RNF20/RNF40/WAC complex interacted with each other, and the coiled-coil regions in RNF20, RNF40 and WAC were identified to directly interact with p53. The R282 site in the p53 DBD, one of the frequent missense mutations associated with p53 mutation-dependent cancer, was demonstrated to be the key binding site for the RNF20/RNF40/WAC complex. Furthermore, knockout of RNF20/RNF40 suppressed the expression levels of p53 and its target genes in HCT116 cells compared with those in wild-type HCT116 cells. Consistent with these results, the R282W mutation in p53 inhibited the expression levels of p53 and its downstream genes by inactivating the interaction between p53 and RNF20/RNF40 compared with those in wild-type HCT116 cells. In conclusion, the results of the present study revealed the molecular mechanism of the interaction between the RNF20/RNF40/WAC complex and p53, and demonstrated that these proteins regulated gene transcription in the DNA damage response.

Precision hyperthermia-induced miRNA-409-3p upregulation inhibits migration, invasion, and EMT of gastric cancer cells by targeting KLF17

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) is widely used for clinical treatment of advanced cancers. However, the regulatory mechanism underlying precise hyperthermia treatment in advanced gastric cancer (AGC) remains unclear. MiR-409-3p is reportedly downregulated in a variety of cancers, although its role in regulating treatment of AGC by precise hyperthermia remains unclear. The underlying mechanisms of miRNA-medicated regulation have been investigated using predicted and validated miRNA-gene targets, confirming the role of miRNA in HIPEC; METHODS: We used quantitative real time PCR (qRT-PCR) to detect miR-409-3p expression in gastric cancer (GC), as well as adjacent normal tissues, following exposure to varying temperatures. We detected miR-409-3p targets using dual-luciferase assay, then performed cell apoptosis, western blotting, invasion, and migration assays to detect GC functions; RESULTS: MiR-409-3p was upregulated and downregulated in precise hyperthermia and AGC, respectively. Moreover, miR-409-3p upregulated the Krüppel-like-factor 17 (KLF17), which subsequently inhibited migration, invasiveness, and epithelial-mesenchymal transition (EMT) but promoted apoptosis in GC cells; CONCLUSIONS: Precise hyperthermia upregulated miR-409-3p and KLF17 indirectly, thereby inhibiting invasion, migration, and EMT, and promoting apoptosis of gastric cancer cells.

Cancer Stemness: p53 at the Wheel

The tumor suppressor p53 maintains an equilibrium between self-renewal and differentiation to sustain a limited repertoire of stem cells for proper development and maintenance of tissue homeostasis. Inactivation of p53 disrupts this balance and promotes pluripotency and somatic cell reprogramming. A few reports in recent years have indicated that prevalent TP53 oncogenic gain-of-function (GOF) mutations further boosts the stemness properties of cancer cells. In this review, we discuss the role of wild type p53 in regulating pluripotency of normal stem cells and various mechanisms that control the balance between self-renewal and differentiation in embryonic and adult stem cells. We also highlight how inactivating and GOF mutations in p53 stimulate stemness in cancer cells. Further, we have explored the various mechanisms of mutant p53-driven cancer stemness, particularly emphasizing on the non-coding RNA mediated epigenetic regulation. We have also analyzed the association of cancer stemness with other crucial gain-of-function properties of mutant p53 such as epithelial to mesenchymal transition phenotypes and chemoresistance to understand how activation of one affects the other. Given the critical role of cancer stem-like cells in tumor maintenance, cancer progression, and therapy resistance of mutant p53 tumors, targeting them might improve therapeutic efficacy in human cancers with TP53 mutations.

TP53 mutational landscape of metastatic head and neck cancer reveals patterns of mutation selection

Background

Head and neck squamous cell carcinoma is a heterogeneous disease with respect to the anatomic site of the primary tumor. On the other hand, it is highly recurrent, and once metastatic, it is associated with poor prognosis. TP53 is the most commonly mutated gene in primary disease. TP53 mutations occur in different structural elements of the protein while the biological outcome can be diverse.

Methods

Here we aimed to find differences in the mutation profile of TP53 in primary and metastatic disease and the impact of TP53 mutations in metastasis, specific copy number alterations, tumor mutation burden and response to immune checkpoint inhibitors. Somatic mutation and clinical data for 512 primary and 134 metastatic biopsies were studied.

Findings

Overall TP53 mutation frequency is significantly lower in metastases compared to primary tumors. One the other hand, missense mutations in the DNA binding region are significantly enriched in metastases and are associated with a common fragile site in chromosome 11, leading to amplification and overexpression of genes with established role in metastasis. Finally, TP53 mutations are associated with higher TMB score in metastatic but not primary tumors, and poorer response to immune checkpoint inhibitors for the latter.

Interpretation

TP53 mutations affect clinical and molecular aspects of head and neck tumorigenesis including metastasis, genetic alterations and therapeutic response.

Funding

This work was supported by a Horizon 2020 grant (801347) to AK, and a Greek General Secretariat for Research and Technology and the Hellenic Foundation for Research and Innovation grant (472‐EpiNotch) to TR.

Physiological and pathological regulation of autophagy in pregnancy

Autophagy exists widely in eukaryotic cells and is regulated by a variety of molecular mechanisms. Its physiological functions include providing energy, maintaining cell homeostasis, and promoting apoptosis of abnormal cells. At present, the regulation of autophagy in tumor, degenerative disease, and cardiovascular disease has attracted much attention. Gradually, the role of autophagy in pregnancy tends to be valued. The previous literature has shown that autophagy can influence the occurrence and maintenance of pregnancy from three aspects: embryo (affecting the process of fertilization and embryonic development and the function of trophoblast cells), maternal (decidualization), and maternal-to-fetal immune crosstalk. Undoubtedly, abnormalities in autophagy levels are associated with a variety of pregnancy complications, such as preeclampsia, fetal growth restriction, and preterm delivery which have been proven by human, animal, and in vitro experiments. The regulation of autophagy is expected to be a target for the treatment of these pregnancy complications. This article reviews the research on autophagy, especially about its physiological and pathological regulation during pregnancy.

Gain-of-Function Mutations in p53 in Cancer Invasiveness and Metastasis

Forty years of research has proven beyond any doubt that p53 is a key regulator of many aspects of cellular physiology. It is best known for its tumor suppressor function, but it is also a regulator of processes important for maintenance of homeostasis and stress response. Its activity is generally antiproliferative and when the cell is damaged beyond repair or intensely stressed the p53 protein contributes to apoptosis. Given its key role in preventing cancer it is no wonder that it is the most frequently mutated gene in human cancer. Surprisingly, a subset of missense mutations occurring in p53 (gain-of-function) cause it to lose its suppressor activity and acquire new functionalities that turn the tumor suppressor protein into an oncoprotein. A solid body of evidence exists demonstrating increased malignancy of cancers with mutated p53 in all aspects considered “hallmarks of cancer”. In this review, we summarize current findings concerning the cellular processes altered by gain-of-function mutations in p53 and their influence on cancer invasiveness and metastasis. We also present the variety of molecular mechanisms regulating these processes, including microRNA, direct transcriptional regulation, protein–protein interactions, and more.

Krüppel-like factors in breast cancer: Function, regulation and clinical relevance

Breast cancer has accounted for the leading cause of cancer-related mortality among women worldwide. Although the progress in its diagnosis and treatment has come at a remarkable pace during the past several decades, there are still a wide array of problems regarding its progression, metastasis and treatment resistance that have not yet been fully clarified. Recently, an increasing number of studies have revealed that some members of Krüppel-like factors(KLFs) are significantly associated with cell proliferation, apoptosis, metastasis, cancer stem cell regulation and prognostic and predictive value for patients in breast cancer, indicating their promising prognostic and predictive potential for breast cancer survival and outcome. In this review, we will summarize our current knowledge of the functions, regulations and clinical relevance of KLFs in breast cancer.

Gain-of-Function Mutant p53: All the Roads Lead to Tumorigenesis

The p53 protein is mutated in about 50% of human cancers. Aside from losing the tumor-suppressive functions of the wild-type form, mutant p53 proteins often acquire inherent, novel oncogenic functions, a phenomenon termed mutant p53 gain-of-function (GOF). A growing body of evidence suggests that these pro-oncogenic functions of mutant p53 proteins are mediated by affecting the transcription of various genes, as well as by protein-protein interactions with transcription factors and other effectors. In the current review, we discuss the various GOF effects of mutant p53, and how it may serve as a central node in a network of genes and proteins, which, altogether, promote the tumorigenic process. Finally, we discuss mechanisms by which "Mother Nature" tries to abrogate the pro-oncogenic functions of mutant p53. Thus, we suggest that targeting mutant p53, via its reactivation to the wild-type form, may serve as a promising therapeutic strategy for many cancers that harbor mutant p53. Not only will this strategy abrogate mutant p53 GOF, but it will also restore WT p53 tumor-suppressive functions.

Targeting the Oncogenic p53 Mutants in Colorectal Cancer and Other Solid Tumors

Colorectal cancer (CRC) is a kind of solid tumor and the third most common cancer type in the world. It is a heterogeneous disease characterized by genetic and epigenetic aberrations. The TP53 mutation is the key step driving the transition from adenoma to adenocarcinoma. The functional roles of TP53 mutation in tumor development have been comprehensively investigated. In CRC, TP53 mutation was associated with poor prognosis and chemoresistance. A gain of function (GOF) of p53 mutants promotes cell proliferation, migration and invasion through multiple mechanisms. Restoring wild type p53 function, depleting p53 mutants, or intervention by targeting the oncogenic downstreams provides potential therapeutic strategies. In this review, we comprehensively summarize the GOF of p53 mutants in CRC progression as well as in some other solid tumors, and discuss the current strategies targeting p53 mutants in malignancies.

TGF-β1-p53 cooperativity regulates a profibrotic genomic program in the kidney: molecular mechanisms and clinical implications

Chronic kidney disease affects >15% of the U.S. population and >850 million individuals worldwide. Fibrosis is the common outcome of many chronic renal disorders and, although the etiology varies (i.e., diabetes, hypertension, ischemia, acute injury, and urologic obstructive disorders), persistently elevated renal TGF-β1 levels result in the relentless progression of fibrotic disease. TGF-β1 orchestrates the multifaceted program of renal fibrogenesis involving proximal tubular dysfunction, failed epithelial recovery and redifferentiation, and subsequent tubulointerstitial fibrosis, eventually leading to chronic renal disease. Recent findings implicate p53 as a cofactor in the TGF-β1-induced signaling pathway and a transcriptional coregulator of several TGF-β1 profibrotic response genes by complexing with receptor-activated SMADs, which are homologous to the small worms (SMA) and Drosophilia mothers against decapentaplegic (MAD) gene families. The cooperative p53-TGF-β1 genomic cluster includes genes involved in cell growth control and extracellular matrix remodeling [e.g., plasminogen activator inhibitor-1 (PAI-1; serine protease inhibitor, clade E, member 1), connective tissue growth factor, and collagen I]. Although the molecular basis for this codependency is unclear, many TGF-β1-responsive genes possess p53 binding motifs. p53 up-regulation and increased p53 phosphorylation; moreover, they are evident in nephrotoxin- and ischemia/reperfusion-induced injury, diabetic nephropathy, ureteral obstructive disease, and kidney allograft rejection. Pharmacologic and genetic approaches that target p53 attenuate expression of the involved genes and mitigate the fibrotic response, confirming a key role for p53 in renal disorders. This review focuses on mechanisms whereby p53 functions as a transcriptional regulator within the TGF-β1 cluster with an emphasis on the potent fibrosis-promoting PAI-1 gene.-Higgins, C. E., Tang, J., Mian, B. M., Higgins, S. P., Gifford, C. C., Conti, D. J., Meldrum, K. K., Samarakoon, R., Higgins, P. J. TGF-β1-p53 cooperativity regulates a profibrotic genomic program in the kidney: molecular mechanisms and clinical implications.

Mutant p53 increases exosome-mediated transfer of miR-21-3p and miR-769-3p to promote pulmonary metastasis

Objective

Tumor metastasis is a complex, multistep process that depends on tumor cells and their communication with the tumor microenvironment. A p53 gain-of-function mutant has been shown to enhance the tumorigenesis, invasion, and metastasis abilities of tumor cells. This study aimed to investigate the roles of p53 R273H mutation in the tumor microenvironment.

Methods

The in vitro and in vivo effects of the p53 R273H mutant on the invasion and metastasis of HCT116 cells were investigated. Exosomes from wild-type and HCT116-TP53(R273H) cells were cocultured with mouse embryonic fibroblasts (MEFs). The roles of differentially expressed exosomal microRNAs identified by microarray analysis were investigated. The functions of the p53 R273H mutant in tumor cells were also investigated via gene expression microarray and quantitative polymerase chain reaction (qPCR) analyses.

Results

Introducing p53 R273H mutant into HCT116 cells significantly potentiated pulmonary metastasis in vivo. In the presence of exosomes derived from HCT116-TP53(R273H) cells, the exosomes were taken up by MEFs and became activated. Microarray analysis showed that the p53 R273H mutation increased the exosomal levels of miR-21-3p and miR-769-3p. Intriguingly, in clinical samples, miR-21-3p and miR-769-3p levels were significantly higher in patients with a p53 mutation than in those without this mutation. Furthermore, both miR-21-3p and miR-769-3p activated fibroblasts and exerted a synergistic effect via their target genes on the transforming growth factor-β (TGF-β)/Smad signaling pathway. The activated fibroblasts excreted cytokine TGF-β and may have reciprocally induced cancer cells to undergo epithelial-mesenchymal transition (EMT). Indeed, HCT116-TP53(R273H) cells showed increased expression of ZEB1 and SNAI2 and decreased transcription of several cell adhesion molecules.

Conclusions

The mutant p53-exosomal miR-21-3p/miR-769-3p-fibroblast-cytokine circuit appears to be responsible for communication between tumor and stromal cells, with exosomal miRNAs acting as a bridge. miR-21-3p and miR-769-3p are potential predictive markers of pulmonary metastasis and candidate targets for therapeutic interventions.

Krüppel-like factor 17 inhibits urokinase plasminogen activator gene expression to suppress cell invasion through the Src/p38/ MAPK signaling pathway in human lung adenocarcionma

Krüppel-like factor 17 (KLF17) has been reported to be involved in invasion and metastasis suppression in lung cancer, but the molecular mechanisms underlying the anti-invasion and anti-metastasis roles of KLF17 in lung cancer are not fully illustrated. Here, we showed that KLF17 inhibited the invasion of A549 and H322 cells; the anti-invasion effect of KLF17 was associated with the suppression of urokinase plasminogen activator (uPA/PLAU) expression. KLF17 can bind with the promoter of uPA and inhibit its expression. Enforced expression of uPA abrogated the anti-invasion effect of KLF17 in A549 and H322 cells. In addition, immunohistochemistry staining showed that the protein expression of KLF17 was negatively correlated with that of uPA in archived samples from patients with lymph node metastasis of lung adenocarcinoma (rho = −0.62, P = 0.01). The mutually exclusive expression of KLF17 with uPA could predict lymph node metastasis for lung adenocarcinoma (AUC = 0.758, P = 0.005). Enforced expression of KLF17 inhibited the expression of phosphorylated Src and phosphorylated p38/MAPK in A549 and H322 cells. The invasiveness of the cells were suppressed by treating with sb203580 (p38/MAPK inhibitor) or HY-13805 (PP2, Src inhibitor). furthermore, p38/MAPK inhibition could block the KLF17-induced reduction of p-p38/MAPK and uPA, and Src inhibition enhanced the KLF17-induced suppression of p-Src and uPA in A549 and H322 cells. In conclusion, our study indicated that KLF17 suppressed the uPA-mediated invasion of lung adenocarcinoma. The Src and p38/MAPK signaling pathways were suggested as mediators of KLF17-induced uPA inhibition, thus providing evidence that KLF17 might be a potential anti-invasion candidate for lung adenocarcinoma.

Li-Fraumeni Syndrome Disease Model: A Platform to Develop Precision Cancer Therapy Targeting Oncogenic p53

Li-Fraumeni syndrome (LFS) is a rare hereditary autosomal dominant cancer disorder. Germline mutations in TP53, the gene encoding p53, are responsible for most cases of LFS. TP53 is also the most commonly mutated gene in human cancers. Because inhibition of mutant p53 is considered to be a promising therapeutic strategy to treat these diseases, LFS provides a perfect genetic model to study p53 mutation-associated malignancies as well as to screen potential compounds targeting oncogenic p53. In this review we briefly summarize the biology of LFS and current understanding of the oncogenic functions of mutant p53 in cancer development. We discuss the strengths and limitations of current LFS disease models, and touch on existing compounds targeting oncogenic p53 and in vitro clinical trials to develop new ones. Finally, we discuss how recently developed methodologies can be integrated into the LFS induced pluripotent stem cell (iPSC) platform to develop precision cancer therapy.

Early-Stage Metastasis Requires Mdm2 and Not p53 Gain of Function

Metastasis of cancer cells to distant organ systems is a complex process that is initiated with the programming of cells in the primary tumor. The formation of distant metastatic foci is correlated with poor prognosis and limited effective treatment options. We and others have correlated Mouse double minute 2 (Mdm2) with metastasis; however, the mechanisms involved have not been elucidated. Here, it is reported that shRNA-mediated silencing of Mdm2 inhibits epithelial-mesenchymal transition (EMT) and cell migration. In vivo analysis demonstrates that silencing Mdm2 in both post-EMT and basal/triple-negative breast cancers resulted in decreased primary tumor vasculature, circulating tumor cells, and metastatic lung foci. Combined, these results demonstrate the importance of Mdm2 in orchestrating the initial stages of migration and metastasis.Implication: Mdm2 is the major factor in the initiation of metastasis. Mol Cancer Res; 15(11); 1598-607. ©2017 AACR.

Anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells through the upregulation of p53 expression

Liriodenine has wide pharmacological functions in phytochemistry, pharmacology and antitumor activities. The anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells, and the underlying mechanisms, are yet to be elucidated. Therefore, the present study investigated the anticancer effects of liriodenine on the cell growth and apoptosis of human breast cancer MCF-7 cells. We used MTT assay to measure cell growth, and flow cytometer and DAPI staining was used to analyze cell apoptosis. Then, Western blot analysis was executed to measure B-cell lymphoma-2 protein (Bcl-2), cyclin D1, vascular endothelial growth factor (VEGF), and p53 protein expression. The effect of liriodenine induced significant apoptosis and suppression of cell growth of the MCF-7 cells. Furthermore, the potential mechanism underlying its antitumor effect on MCF-7 cells may result from activation of caspase-3 activity, Bcl-2, cyclin D1 and VEGF, and promotion of p53 protein expression in MCF-7 cells. Therefore, the present results indicated that the anticancer effects of liriodenine suppress cell growth and induce the apoptosis of human breast cancer MCF-7 cells through inhibition of Bcl-2, cyclin D1 and VEGF expression, and upregulation of p53 expression. Therefore, liriodenine may be a potential therapy for the treatment of human breast cancer.

Mutant p53 Protein and the Hippo Transducers YAP and TAZ: A Critical Oncogenic Node in Human Cancers

p53 protein is a well-known tumor suppressor factor that regulates cellular homeostasis. As it has several and key functions exerted, p53 is known as “the guardian of the genome” and either loss of function or gain of function mutations in the TP53 coding protein sequence are involved in cancer onset and progression. The Hippo pathway is a key regulator of developmental and regenerative physiological processes but if deregulated can induce cell transformation and cancer progression. The p53 and Hippo pathways exert a plethora of fine-tuned functions that can apparently be in contrast with each other. In this review, we propose that the p53 status can affect the Hippo pathway function by switching its outputs from tumor suppressor to oncogenic activities. In detail, we discuss: (a) the oncogenic role of the protein complex mutant p53/YAP; (b) TAZ oncogenic activation mediated by mutant p53; (c) the therapeutic potential of targeting mutant p53 to impair YAP and TAZ oncogenic functions in human cancers.

p53 and its mutants on the slippery road from stemness to carcinogenesis

Normal development, tissue homeostasis and regeneration following injury rely on the proper functions of wide repertoire of stem cells (SCs) persisting during embryonic period and throughout the adult life. Therefore, SCs employ robust mechanisms to preserve their genomic integrity and avoid heritage of mutations to their daughter cells. Importantly, propagation of SCs with faulty DNA as well as dedifferentiation of genomically altered somatic cells may result in derivation of cancer SCs, which are considered to be the driving force of the tumorigenic process. Multiple experimental evidence suggest that p53, the central tumor suppressor gene, plays a critical regulatory role in determination of SCs destiny, thereby eliminating damaged SCs from the general SC population. Notably, mutant p53 proteins do not only lose the tumor suppressive function, but rather gain new oncogenic function that markedly promotes various aspects of carcinogenesis. In this review, we elaborate on the role of wild type and mutant p53 proteins in the various SCs types that appear under homeostatic conditions as well as in cancer. It is plausible that the growing understanding of the mechanisms underlying cancer SC phenotype and p53 malfunction will allow future optimization of cancer therapeutics in the context of precision medicine.

Influence of KLF17 overexpression on epithelial-mesenchymal transition and invasion of SW480 colorectal cancer cells

AIM

To assess the impact of KLF17 overexpression on the epithelial-mesenchymal transition (EMT) and invasive ability of SW480 colorectal cancer cells.

METHODS

The recombinant KLF17 expression plasmid with EGFP was transfected into SW480 cells, and non-transfected SW480 cells and SW480 cells transfected with the empty vector were used as controls. The changes in KLF17 mRNA and protein expression were detected by real-time PCR and Western blot at 48 h after transfection with the recombinant KLF17 expression plasmid. The changes in the expression of epithelial and mesenchymal makers in SW480 cells were detected by real-time PCR and Western blot. Transwell chamber invasion assay was used to investigate the effect of KLF17 gene transfection on the invasive potential of SW480 cells.

RESULTS

The expression levels of KLF17 mRNA and protein in SW480 cells transfected with the recombinant plasmid (2.5087 ± 0.0288; 0.6100 ± 0.0579) were significantly increased compared with those in non-transfected SW480 cells (1.0000 ± 0.0198; 0.3543 ± 0.0340) (P < 0.01 for both). The expression levels of E-cadherin mRNA and protein in SW480 cells transfected with the recombinant plasmid (2.0704 ± 0.0620; 0.5446 ± 0.0245) were significantly higher than those in non-transfected SW480 cells (1.0000 ± 0.0106; 0.3952 ± 0.0430) (P < 0.01 for both), while the expression levels of vimentin mRNA and protein in SW480 cells transfected with the recombinant plasmid (0.4622 ± 0.0279; 0.3290 ± 0.0367) were significantly lower than those in non-transfected SW480 cells (1.0000 ± 0.0780; 0.5229 ± 0.0496) (P < 0.01 for both). After transfection with the recombination KLF17 expression plasmid, the invasive ability of SW480 cells (86.67 ± 10.97) was significantly lower than that of non-transfected SW480 cells (145.30 ± 11.37) and SW480 cells transfected with the empty vector (135.33 ± 12.66) (P < 0.01 for both).

CONCLUSION

KLF17 may inhibit SW480 cancer cell invasion by inhibiting EMT.

Novel targets and interaction partners of mutant p53 Gain-Of-Function

In many human cancers p53 expression is lost or a mutant p53 protein is expressed. Over the past 15 years it has become apparent that a large number of these mutant p53 proteins have lost wild type function, but more importantly have gained functions that promote tumorigenesis and drive chemo-resistance, invasion and metastasis. Many researchers have investigated the underlying mechanisms of these Gain-Of-Functions (GOFs) and it has become apparent that many of these functions are the result of mutant p53 hijacking other transcription factors. In this review, we summarize the latest research on p53 GOF and categorize these in light of the hallmarks of cancer as presented by Hannahan and Weinberg.

Lectin microarray technology identifies specific lectins related to lymph node metastasis of advanced gastric cancer

BACKGROUND

Although various molecular profiling technologies have the potential to predict specific tumor phenotypes, the comprehensive profiling of lectin-bound glycans in human cancer tissues has not yet been achieved.

METHODS

We examined 242 advanced gastric cancer (AGC) patients without or with lymph node metastasis-N0 (n = 62) or N+ (n = 180)-by lectin microarray, and identified the specific lectins highly associated with AGC phenotypes.

RESULTS

In seven gastric cancer cell lines, in contrast to expressed-in-cancer lectins, not-expressed-in-cancer (NEC) lectins were tentatively designated by lectin microarray. Binding signals of the specific lectins were robustly reduced in AGC patients with N+ status as compared with those with N0 status. The receiver operating characteristic curve determined the optimal cutoff value to differentiate N0 status from N+ status, and subsequent profiling of NEC lectins identified Vicia villosa agglutinin (VVA) association with the significant other lectins involved in lymph node metastasis. VVA reaction was clearly found on cancer cells, suggesting that it may result from carcinoma-stroma interaction in primary AGC, because VVA is an NEC lectin. Most intriguingly, VVA reaction was remarkably attenuated in the tumor cells of the metastatic lymph nodes, even if it was recognized in primary AGC. In AGC, histological type was strongly associated with soybean agglutinin and Bauhinia purpurea lectin, whereas p53 mutation was the best correlated with Griffonia simplicifolia lectin II.

CONCLUSIONS

Lectin microarrays can be used to very accurately quantify the reaction of glycans with tumor tissues, and such profiles may represent the specific phenotypes, including N+ status, histological type, or p53 mutation of AGC.

Gain of function of mutant p53: R282W on the peak?

Mutant p53 proteins commonly lose their tumor suppression function and gain novel oncogenic functions (gain of function (GOF)). Different p53 mutations are often considered in one class in biological and clinical studies. However, recent studies have revealed that p53 mutations are biologically and clinically distinct. The R282W mutant associates with earlier onset of familial cancers and poorer outcome of cancer patients, suggesting a more prominent GOF effect of this specific mutant. Here we discuss our current understanding on the multifaceted effects of R282W mutation, including its structural features, signaling pathways and clinical implications. The destabilizing nature, aggregation proneness, altered transcriptome and interactome may collaboratively contribute to the unique phenotype of R282W mutation. The quest for mechanistic insights into the unique GOF effects of R282W mutation would further our understanding of the biology of mutant proteins in cancers, and enforce the development of more effective targeted therapies.

Krüppel-like factor 17, a novel tumor suppressor: its low expression is involved in cancer metastasis

Krüppel-like factor (KLF) family is highly conserved zinc finger transcription factors that regulate cell proliferation, differentiation, apoptosis, and migration. KLF17 is a member of the KLF family. Recent studies have demonstrated that KLF17 low expression and inactivation are caused by microRNA, gene mutation, and loss of heterozygosity in human tumors, which participates in tumor progression. KLF17 low expression increases cancer metastatic viability; its mechanism is that low KLF17 mediates epithelial-mesenchymal transition (EMT) through regulating EMT-related genes expression; the reduced-KLF17 also increases cancer metastasis though upregulating inhibitor of DNA binding 1 (ID1). Additionally, mutant p53 proteins are capable of developing a complex with KLF17, which mediate the depletion of KLF17 inhibiting EMT gene transcription and increases cancer metastasis. KLF17 downregulation also mediates the activation of TGF-β pathway.

Tumor-suppressive p53 Signaling Empowers Metastatic Inhibitor KLF17-dependent Transcription to Overcome Tumorigenesis in Non-small Cell Lung Cancer

Metastasis, which is controlled by concerted action of multiple genes, is a complex process and is an important cause of cancer death. Krüppel-like factor 17 (KLF17) is a negative regulator of metastasis and epithelial-mesenchymal transition (EMT) during cancer progression. However, the underlying molecular mechanism and biological relevance of KLF17 in cancer cells are poorly understood. Here, we show that tumor suppressor protein p53 plays an integral role to induce KLF17 expression in non-small cell lung cancer (NSCLC). p53 is recruited to the KLF17 promoter and results in the formation of p53-DNA complex. p53 enhances binding of p300 and favors histone acetylation on the KLF17 promoter. Mechanistically, p53 physically interacts with KLF17 and thereby enhances the anti-metastatic function of KLF17. p53 empowers KLF17-mediated EMT genes transcription via enhancing physical association of KLF17 with target gene promoters. Nutlin-3 recruits KLF17 to EMT target gene promoters and results in the formation of KLF17-DNA complex via a p53-dependent pathway. p53 depletion abrogates DNA binding affinity of KLF17 to EMT target gene promoters. KLF17 is critical for p53 cellular activities in NSCLC. Importantly, KLF17 enhances p53 transcription to generate a novel positive feedback loop. KLF17 depletion accelerates lung cancer cell growth in response to chemotherapy. Mechanistically, we found that KLF17 increases the expression of tumor suppressor genes p53, p21, and pRB. Functionally, KLF17 required p53 to suppress cancer cell invasion and migration in NSCLC. In conclusion, our study highlights a novel insight into the anti-EMT effect of KLF17 via a p53-dependent pathway in NSCLC, and KLF17 may be a new therapeutic target in NSCLC with p53 status.

Metabolic tumor burden is associated with major oncogenomic alterations and serum tumor markers in patients with resected pancreatic cancer

Pancreatic cancer is an aggressive and lethal disease with an overall 5-year survival rate of only 5%. Studies have demonstrated the ability of (18)F-fludrodeoxyglucose ((18)F-FDG) positron emission tomography/computed tomography (PET/CT) to measure the metabolic tumor burden in patients with various tumors, including pancreatic cancer. In a previous study, we investigated the predictive significance of the metabolic tumor burden in terms of the metabolic tumor volume (MTV) and total lesion glycolysis (TLG). In this study, we analyzed the correlation between metabolic tumor burden and the status of the KRAS, TP53, CDKN2A/p16, and SMAD4/DPC4 genes. Our results showed that the metabolic tumor burden was associated with oncogenomic alterations that reflected the abnormal expression of carbohydrate metabolic enzymes (GLUT1, ALDOA and FBP1). We also identified a linear correlation between serum tumor markers and the metabolic tumor burden. To estimate the metabolic tumor burden when (18)F-FDG PET/CT is not available, we used the linear regression models to establish equations for MTV and TLG using CA19-9 and CA125 as independent variables. Our results suggest that the metabolic tumor burden, as evaluated by (18)F-FDG PET/CT or estimated by serum tumor markers, may be suitable for monitoring treatment response and disease progression of pancreatic cancer. Further research is needed to better understand why pancreatic cancer patients with abnormal expressions of TP53, CDKN2A/p16, and SMAD4/DPC4 get high metabolic tumor burden.

Efficient one-pot synthesis of trans-Pt(ii)(salicylaldimine)(4-picoline)Cl complexes: effective agents for enhanced expression of p53 tumor suppressor genes

One-pot synthesizedtrans-Pt(ii)(salicylaldimine)(4-picoline)Cl complexes showed promisingin vitrocytotoxicity in MCF-7 and A549 cancer cell lines.