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Background Protein phosphatase magnesium-dependent 1 delta (PPM1D), also referred to as wild-type p53-induced phosphatase 1 (Wip1) or protein phosphatase 2C delta (PP2Cδ), is an oncogenic nuclear serine/threonine phosphatase belonging to the PP2C family. However, the knowledge regarding PPM1D mRNA expression, tumor immunity, and the prognosis in hepatocellular carcinoma (HCC) is scanty. Methods We analyzed PPM1D, including its expression in both the normal and tumor tissue using the Sangerbox database and Tumor Immune Estimation Resource (TIMER). We evaluated its correlation with prognosis in different tumor types by the Kaplan-Meier plotter and Gene Expression Profiling Interactive Analysis (GEPIA). The correlations between PPM1D and the cancer immune infiltrates were determined using TIMER. The correlations between PPM1D expression and gene marker sets of the immune infiltrates were established by both the TIMER and GEPIA. Immunohistochemistry was performed to detect the expression of Wip1 protein encoded by PPM1D in HCC, and the relationship between Wip1 expression and the prognosis of HCC were analyzed. Results We found out that PPM1D mRNA expression was significantly higher in several human cancers, including HCC, than in the corresponding normal human tissues. The PPM1D mRNA high expression in HCC was significantly correlated with poor prognosis. The expression was associated with progression-free survival (PFS) in multiple HCC patients' cohorts (PFS HR = 1.5, P = 0.0066). This was especially in early stage (stage 1) and AJCC_T 1 of HCC. Besides, PPM1D mRNA expression indicated a positive correlation with tumor-infiltrating Monocytes, tumor-associated macrophages (TAMs), M1 Macrophage, M2 Macrophage, dendritic cells (DCs), T-helper (Th) and Treg. Wip1 was higher in HCC than paracancerous tissue. High expression of Wip1 was associated with poor prognosis of HCC. Conclusion Our findings suggested that PPM1D mRNA is critical in activating tumor immunity. Besides, they implied that PPM1D could be a potential prognostic biomarker for cancer progression. Moreover, it correlated with tumor immune cell infiltration in HCC.

A greater understanding of factors causing cancer initiation, progression and evolution is of paramount importance. Among them, the serine/threonine phosphatase PPM1D, also referred to as wild-type p53-induced phosphatase 1 (Wip1) or protein phosphatase 2C delta (PP2Cδ), is emerging as an important oncoprotein due to its negative regulation on a number of crucial cancer suppressor pathways. Initially identified as a p53-regulated gene, PPM1D has been afterwards found amplified and more recently mutated in many human cancers such as breast cancer. The latest progress in this field further reveals that selective inhibition of PPM1D to delay tumor onset or reduce tumor burden represents a promising anti-cancer strategy. Here, we review the advances in the studies of the PPM1D activity and its relevance to various cancers, and recent progress in development of PPM1D inhibitors and discuss their potential application in cancer therapy. Consecutive research on PPM1D and its relationship with cancer is essential, as it ultimately contributes to the etiology and treatment of cancer.

Background Jansen‐de Vries syndrome is a rare autosomal dominant neurodevelopmental disorder caused by pathogenic variants in the last and penultimate exons of the PPM1D gene. It is characterized by delayed psychomotor development, intellectual disability with speech delay, behavioral abnormalities, and dysmorphic features. Up to date, only 17 affected patients have been reported worldwide (no report in Chinese). Methods Here, we analyzed the clinical data and genetic test results of a Chinese patient with Jansen‐de Vries syndrome admitted in our hospital in May 2019. Results We report a 9‐month‐old boy carrying a pathogenic variant (c.1254_1255del, p.(V419Qfs*14)) in PPM1D exon 5, which can account for his phenotype. Most of his clinical features overlap with the reported phenotype, such as growth retardation, feeding difficulties, constipation, congenital abnormalities (such as atrial septal defect, ventricular septal defect, and patent ductus arteriosus), small hands and feet with broad forehead, low‐set posteriorly rotated ears, wide mouth with thin upper lip and pointed chin; however, he also presented with additional features like hepatomegaly and left inguinal hernia. Conclusion This is the first published case of Jansen‐de Vries syndrome in Chinese population, which will help us to enrich the clinical spectrum of this syndrome., Jansen‐de Vries syndrome is a rare autosomal dominant neurodevelopmental disorder caused by pathogenic variants in the last and penultimate exons of the PPM1D gene. Up to date only 17 affected patients have been reported worldwide (no report in Chinese). This is the first published case of Jansen‐de Vries syndrome in Chinese population, which will help us to enrich the clinical spectrum of this syndrome.

// Kensuke Kojima 1 , Aya Maeda 1 , Mariko Yoshimura 1 , Yuki Nishida 1 , Shinya Kimura 1 1 Department of Hematology, Respiratory Medicine and Oncology, Division of Medicine, Saga University, Saga, Japan Correspondence to: Kensuke Kojima, email: kkojima@cc.saga-u.ac.jp Keywords: PPM1D, p53, MDM2, p38 MAPK, mantle cell lymphoma Received: March 22, 2016 Accepted: September 02, 2016 Published: September 08, 2016 ABSTRACT PPM1D is a serine/threonine phosphatase that negatively regulates key DNA damage response proteins, such as p53, p38 MAPK, histone H2A.X, and ATM. We investigated the pathophysiological significance of PPM1D and its therapeutic targeting by the novel PPM1D inhibitor GSK2830371 in mantle cell lymphoma (MCL). Oncomine-based analyses indicated increased PPM1D mRNA levels in MCL cells compared with their normal counterpart cells. Higher PPM1D expression was associated with higher expression of the proliferation gene signature and poorer prognosis in patients. Eight MCL (three p53 wild-type and five mutant) cell lines were exposed to GSK2830371. GSK2830371 inhibited the cell growth, being prominent in p53 wild-type cells. GSK2830371 induced apoptosis in sensitive cells, as evidenced by induction of phosphatidylserine externalization and loss of mitochondrial membrane potential. p53 knockdown de-sensitized cell sensitivity. GSK2830371 increased the levels of total and Ser15-phosphorylated p53, and p53 targets p21 and PUMA. GSK2830371 and the MDM2 inhibitor Nutlin-3a acted synergistically in p53 wild-type cells. Interestingly, GSK2830371 sensitized MCL cells to bortezomib and doxorubicin in p53 wild-type and mutant cells; p38 signaling appeared to be involved in the GSK2830371/bortezomib lethality. PPM1D inhibition may represent a novel therapeutic strategy for MCL, which can be exploited in combination therapeutic strategies for MCL.

We combined de novo mutation (DNM) data from 10,927 individuals with developmental delay and autism to identify 253 candidate neurodevelopmental disease genes with an excess of missense and/or likely gene-disruptive (LGD) mutations. Of these genes, 124 reach exome-wide significance (P

Background: PPM1D (WIP1) negatively regulates by dephosphorylation many proteins including p53 tumour suppressor. The truncating mutations (nonsense and frameshift) in exon 6 of PPM1D were found recently in blood cells of patients with breast, ovarian or colorectal cancer. These mutants code for gain-of-function PPM1D with retained phosphatase activity. Their significance in carcinogenesis is unknown. Methods: The exon 6 of PPM1D was sequenced in blood DNA of 543 non-small-cell lung cancer patients (NSCLC). The functional significance of selected PPM1D alterations (Arg458X, Lys469Glu) was compared with the wild-type gene and examined by recombinant DNA techniques, immunoblotting and luciferase reporter assays. Results: The frameshift mutations were found in five NSCLC patients (5/543; 0.92%), all of them had squamous cell carcinomas (5/328; 1.5%). All patients with the mutations were exposed, before the blood collection, to the DNA damaging agents as a part of chemotherapeutic regimen. Functional tests demonstrated that truncating mutation Arg458X causes enhancement of dephosphorylation activity of PPM1D toward serine 15 of p53, whereas Lys469Glu version is equivalent to the wild-type. Neither version of PPM1D (wild-type, Arg458X, Lys469Glu) significantly modulated the ability of p53 to transactivate promoters of the examined p53-target genes (BAX and MDM2). Conclusions: The truncating mutations of PPM1D are present in blood DNA of NSCLC patients at frequency similar to percentage determined for ovarian cancer patients. Our findings raise a question if the detected lesions are a result of chemotherapy.

Background Protein phosphatase magnesium-dependent 1δ (PPM1D) is a p53-induced serine/threonine phosphatase, which is overexpressed in various human cancers. A recent study reported that a mutation in the PPM1D gene is associated with poor prognosis in brainstem gliomas. In this study, we evaluated the utility of PPM1D as a prognostic biomarker of adult supratentorial diffuse astrocytic and oligodendroglial tumors. Methods To investigate PPM1D protein expression, mRNA expression, and copy number changes, immunohistochemistry, RNAscope in situ hybridization, and fluorescence in situ hybridization were performed in 84 adult supratentorial diffuse gliomas. We further analyzed clinical characteristics and overall survival (OS) according to PPM1D protein expression, and examined its correlation with other glioma biomarkers such as isocitrate dehydrogenase (IDH) mutation, and p53 expression. Results Forty-six cases (54.8%) were PPM1D-positive. PPM1D expression levels were significantly correlated with PPM1D transcript levels (p= .035), but marginally with PPM1D gene amplification (p=.079). Patients with high-grade gliomas showed a higher frequency of PPM1D expression than those with low-grade gliomas (p

Protein phosphatase, Mg2+/Mn2+ dependent, 1D (PPM1D) has been associated with carcinogenesis. The present study investigated PPM1D expression as a potential biomarker in colorectal cancer (CRC). PPM1D expression was assessed using immunohistochemistry in 368 patients with CRC. The correlation between PPM1D expression, clinicopathological features and prognosis was analyzed. PPM1D small interfering (si)RNA-induced PPM1D silencing was performed in CRC cell lines to assess the effect of PPM1D on tumor cell proliferation and invasion in vitro. A total of 68.48% (252/368) of the CRC samples displayed high PPM1D expression. By contrast, only 9.24% (34/368) of the matched non-cancerous tissue samples exhibited high PPM1D expression. High PPM1D expression was correlated with node metastasis (P=0.0024), distant metastasis (P

Recent studies suggest that medulloblastoma, the most common malignant brain tumor of childhood, is comprised of four disease variants. The WIP1 oncogene is overexpressed in Group 3 and 4 tumors, which contain medulloblastomas with the most aggressive clinical behavior. Our data demonstrate increased WIP1 expression in metastatic medulloblastomas, and inferior progression-free and overall survival of patients with WIP1 high-expressing medulloblastoma. Microarray analysis identified up-regulation of genes involved in tumor metastasis, including the G protein-coupled receptor CXCR4, in medulloblastoma cells with high WIP1 expression. Stimulation with the CXCR4 ligand SDF1ααactivated PI-3 kinase signaling, and promoted growth and invasion of WIP1 high-expressing medulloblastoma cells in a p53-dependent manner. When xenografted into the cerebellum of immunodeficient mice, medulloblastoma cells with stable or endogenous high WIP1 expression exhibited strong expression of CXCR4 and activated AKT in primary and invasive tumor cells. WIP1 or CXCR4 knock-down inhibited medulloblastoma growth and invasion. WIP1 knock-down also improved the survival of mice xenografted with WIP1 high-expressing medulloblastoma cells. WIP1 knock-down inhibited cell surface localization of CXCR4 by suppressing expression of the G protein receptor kinase 5, GRK5. Restoration of wild-type GRK5 promoted Ser339 phosphorylation of CXCR4 and inhibited the growth of WIP1-stable medulloblastoma cells. Conversely, GRK5 knock-down inhibited Ser339 phosphorylation of CXCR4, increased cell surface localization of CXCR4, and promoted the growth of medulloblastoma cells with low WIP1 expression. These results demonstrate cross-talk among WIP1, CXCR4, and GRK5, which may be important for the aggressive phenotype of a subclass of medulloblastomas in children.

Children with severe, undiagnosed developmental disorders (DDs) are enriched for damaging de novo mutations (DNMs) in developmentally important genes. We exome sequenced 4,294 families with children with DDs, and meta-analysed these data with published data on 3,287 children with similar disorders. We show that the most significant factors influencing the diagnostic yield of de novo mutations are the sex of the child, the relatedness of their parents and the age of both father and mother. We identified 95 genes enriched for damaging de novo mutation at genome-wide significance (P < 5 x 10-7), including fourteen genes for which compelling data for causation was previously lacking. The large number of genome-wide significant findings allow us to demonstrate that, at current cost differentials, exome sequencing has much greater power than genome sequencing for novel gene discovery in genetically heterogeneous disorders. We estimate that 42.5% of our cohort likely carry pathogenic de novo single nucleotide variants (SNVs) and indels in coding sequences, with approximately half operating by a loss-of-function mechanism, and the remainder being gain-of-function. We established that most haploinsufficient developmental disorders have already been identified, but that many gain-of-function disorders remain to be discovered. Extrapolating from the DDD cohort to the general population, we estimate that de novo dominant developmental disorders have an average birth prevalence of 1 in 168 to 1 in 377, depending on parental age.

Ovarian cancer is the most lethal gynecological malignancy. Cisplatin and its derivatives are first-line chemotherapeutics, and their resistance is a major hurdle in successful ovarian cancer treatment. Understanding the molecular dysregulation underlying chemoresistance is important for enhancing therapeutic outcome. Here, we review two established pathways in cancer chemoresistance. p53 is a major tumor suppressor regulating proliferation and apoptosis, and its mutation is a frequent event in human malignancies. The PI3K/Akt axis is a key oncogenic pathway regulating survival and tumorigenesis by controlling several tumor suppressors, including p53. The interplay between these pathways is well established, although the oncogenic phosphatase PPM1D adds a new layer to this intricate relationship and provides new insights into the processes determining cell fate. Inhibition of the PI3K/Akt pathway by functional food compounds as an adjunct to chemotherapeutics may tip the balance in favor of apoptosis rather than survival, enhancing therapeutic efficacy, and reducing side effects.

Wild-type p53-induced phosphatase 1 (WIP1) is a serine/threonine phosphatase that dephosphorylates proteins in the ataxia telangiectasia mutated (ATM)-initiated DNA damage response pathway. WIP1 may have a homeostatic role in ATM signaling by returning the cell to a normal pre-stress state following completion of DNA repair. To better understand the effects of WIP1 on ATM signaling, we crossed Atm-deficient mice to Wip1-deficient mice and characterized phenotypes of the double knockout progeny. We hypothesized that the absence of Wip1 might rescue Atm deficiency phenotypes. Atm null mice, like ATM-deficient humans with the inherited syndrome ataxia telangiectasia, exhibit radiation sensitivity, fertility defects, and are T-cell lymphoma prone. Most double knockout mice were largely protected from lymphoma development and had a greatly extended lifespan compared with Atm null mice. Double knockout mice had increased p53 and H2AX phosphorylation and p21 expression compared with their Atm null counterparts, indicating enhanced p53 and DNA damage responses. Additionally, double knockout splenocytes displayed reduced chromosomal instability compared with Atm null mice. Finally, doubly null mice were partially rescued from gametogenesis defects observed in Atm null mice. These results indicate that inhibition of WIP1 may represent a useful strategy for cancer treatment in general and A-T patients in particular.

The Wild-type p53-induced phosphatase 1, Wip1 (or PPM1D), is unusual in that it is a serine/threonine phosphatase with oncogenic activity. A member of the type 2C phosphatases (PP2Cdelta), Wip1 has been shown to be amplified and overexpressed in multiple human cancer types, including breast and ovarian carcinomas. In rodent primary fibroblast transformation assays, Wip1 cooperates with known oncogenes to induce transformed foci. The recent identification of target proteins that are dephosphorylated by Wip1 has provided mechanistic insights into its oncogenic functions. Wip1 acts as a homeostatic regulator of the DNA damage response by dephosphorylating proteins that are substrates of both ATM and ATR, important DNA damage sensor kinases. Wip1 also suppresses the activity of multiple tumor suppressors, including p53, ATM, p16(INK4a) and ARF. We present evidence that the suppression of p53, p38 MAP kinase, and ATM/ATR signaling pathways by Wip1 are important components of its oncogenicity when it is amplified and overexpressed in human cancers.

Summary Clonal hematopoiesis (CH), in which stem cell clones dominate blood production, becomes increasingly common with age and can presage malignancy development. The conditions that promote ascendancy of particular clones are unclear. We found that mutations in PPM1D (protein phosphatase Mn2+/Mg2+-dependent 1D), a DNA damage response regulator that is frequently mutated in CH, were present in one-fifth of patients with therapy-related acute myeloid leukemia or myelodysplastic syndrome and strongly correlated with cisplatin exposure. Cell lines with hyperactive PPM1D mutations expand to outcompete normal cells after exposure to cytotoxic DNA damaging agents including cisplatin, and this effect was predominantly mediated by increased resistance to apoptosis. Moreover, heterozygous mutant Ppm1d hematopoietic cells outcompeted their wild-type counterparts in vivo after exposure to cisplatin and doxorubicin, but not during recovery from bone marrow transplantation. These findings establish the clinical relevance of PPM1D mutations in CH and the importance of studying mutation-treatment interactions. Video Abstract, Graphical Abstract, Highlights • PPM1D is mutated in ∼20% of patients with therapy-related AML or MDS • PPM1D mutations are associated with prior exposure to specific DNA-damaging agents • Mutant PPM1D confers a survival advantage after cisplatin-induced stress • PPM1D mutants lack an advantage under bone marrow transplantation stress, Cytotoxic chemotherapies put patients at risk for future hematopoietic malignancies. Goodell and colleagues show that PPM1D mutations confer a survival advantage onto hematopoietic clones by rendering them resistant to DNA-damaging agents such as cisplatin. Selective pressures will be specific to different mutations and should be considered in choice of chemotherapy.

Background Human T-cell Leukemia Virus type 1 (HTLV-1) infects 20 million individuals world-wide and causes Adult T-cell Leukemia/Lymphoma (ATLL), a highly aggressive T-cell cancer. ATLL is refractory to treatment with conventional chemotherapy and fewer than 10% of afflicted individuals survive more than 5 years after diagnosis. HTLV-1 encodes a viral oncoprotein, Tax, that functions in transforming virus-infected T-cells into leukemic cells. All ATLL cases are believed to have reduced p53 activity although only a minority of ATLLs have genetic mutations in their p53 gene. It has been suggested that p53 function is inactivated by the Tax protein. Results Using genetically altered mice, we report here that Tax expression does not achieve a functional equivalence of p53 inactivation as that seen with genetic mutation of p53 (i.e. a p53−/− genotype). Thus, we find statistically significant differences in tumorigenesis between Tax+p53+/+versus Tax+p53−/− mice. We also find a role contributed by the cellular Wip1 phosphatase protein in tumor formation in Tax transgenic mice. Notably, Tax+Wip1−/− mice show statistically significant reduced prevalence of tumorigenesis compared to Tax+Wip1+/+ counterparts. Conclusions Our findings provide new insights into contributions by p53 and Wip1 in the in vivo oncogenesis of Tax-induced tumors in mice.

Background Human T-cell Leukemia Virus type 1 (HTLV-1) infects 20 million individuals world-wide and causes Adult T-cell Leukemia/Lymphoma (ATLL), a highly aggressive T-cell cancer. ATLL is refractory to treatment with conventional chemotherapy and fewer than 10% of afflicted individuals survive more than 5 years after diagnosis. HTLV-1 encodes a viral oncoprotein, Tax, that functions in transforming virus-infected T-cells into leukemic cells. All ATLL cases are believed to have reduced p53 activity although only a minority of ATLLs have genetic mutations in their p53 gene. It has been suggested that p53 function is inactivated by the Tax protein. Results Using genetically altered mice, we report here that Tax expression does not achieve a functional equivalence of p53 inactivation as that seen with genetic mutation of p53 (i.e. a p53 −/− genotype). Thus, we find statistically significant differences in tumorigenesis between Tax + p53 +/+ versus Tax + p53 −/− mice. We also find a role contributed by the cellular Wip1 phosphatase protein in tumor formation in Tax transgenic mice. Notably, Tax + Wip1 −/− mice show statistically significant reduced prevalence of tumorigenesis compared to Tax + Wip1 +/+ counterparts. Conclusions Our findings provide new insights into contributions by p53 and Wip1 in the in vivo oncogenesis of Tax-induced tumors in mice.

Purpose: To characterize the molecular genetic profiles of grade 3 invasive ductal carcinomas of no special type using high-resolution microarray-based comparative genomic hybridization (aCGH) and to identify recurrent amplicons harboring putative therapeutic targets associated with luminal, HER-2, and basal-like tumor phenotypes. Experimental Design: Ninety-five grade 3 invasive ductal carcinomas of no special type were classified into luminal, HER-2, and basal-like subgroups using a previously validated immunohistochemical panel. Tumor samples were microdissected and subjected to aCGH using a tiling path 32K BAC array platform. Selected regions of recurrent amplification were validated by means of in situ hybridization. Expression of genes pertaining to selected amplicons was investigated using quantitative real-time PCR and gene silencing was done using previously validated short hairpin RNA constructs. Results: We show that basal-like and HER-2 tumors are characterized by “sawtooth” and “firestorm” genetic patterns, respectively, whereas luminal cancers were more heterogeneous. Apart from confirming known amplifications associated with basal-like (1q21, 10p, and 12p), luminal (8p12, 11q13, and 11q14), and HER-2 (17q12) cancers, we identified previously unreported recurrent amplifications associated with each molecular subgroup: 19q12 in basal-like, 1q32.1 in luminal, and 14q12 in HER-2 cancers. PPM1D gene amplification (17q23.2) was found in 20% and 8% of HER-2 and luminal cancers, respectively. Silencing of PPM1D by short hairpin RNA resulted in selective loss of viability in tumor cell lines harboring the 17q23.2 amplification. Conclusions: Our results show the power of aCGH analysis in unraveling the genetic profiles of specific subgroups of cancer and for the identification of novel therapeutic targets.