Gene Summary

Gene:POLI; DNA polymerase iota
Aliases: eta2, RAD30B, RAD3OB
Summary:The protein encoded by this gene is an error-prone DNA polymerase involved in DNA repair. The encoded protein promotes DNA synthesis across lesions in the template DNA, which other polymerases cannot do. The encoded polymerase inserts deoxynucleotides across lesions and then relies on DNA polymerase zeta to extend the nascent DNA strand to bypass the lesion. [provided by RefSeq, May 2017]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:DNA polymerase iota
Source:NCBIAccessed: 30 August, 2019


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1994-2019)
Graph generated 30 August 2019 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 30 August, 2019 using data from PubMed, MeSH and CancerIndex

Latest Publications: POLI (cancer-related)

D'Alise AM, Leoni G, Cotugno G, et al.
Adenoviral vaccine targeting multiple neoantigens as strategy to eradicate large tumors combined with checkpoint blockade.
Nat Commun. 2019; 10(1):2688 [PubMed] Free Access to Full Article Related Publications
Neoantigens (nAgs) are promising tumor antigens for cancer vaccination with the potential of inducing robust and selective T cell responses. Genetic vaccines based on Adenoviruses derived from non-human Great Apes (GAd) elicit strong and effective T cell-mediated immunity in humans. Here, we investigate for the first time the potency and efficacy of a novel GAd encoding multiple neoantigens. Prophylactic or early therapeutic vaccination with GAd efficiently control tumor growth in mice. In contrast, combination of the vaccine with checkpoint inhibitors is required to eradicate large tumors. Gene expression profile of tumors in regression shows abundance of activated tumor infiltrating T cells with a more diversified TCR repertoire in animals treated with GAd and anti-PD1 compared to anti-PD1. Data suggest that effectiveness of vaccination in the presence of high tumor burden correlates with the breadth of nAgs-specific T cells and requires concomitant reversal of tumor suppression by checkpoint blockade.

Zou S, Xu Y, Chen X, et al.
DNA polymerase iota (Pol ι) promotes the migration and invasion of breast cancer cell via EGFR-ERK-mediated epithelial to mesenchymal transition.
Cancer Biomark. 2019; 24(3):363-370 [PubMed] Related Publications
BACKGROUND AND OBJECTIVE: Dysregulation of DNA polymerase iota (Pol ι) in breast cancer might contribute to the accumulation of genomic mutations and promotes breast cancer progression. In this study we explored the clinical relevance and biological function of Pol ι in breast cancer.
METHODS: qRT-PCR was used to determine the expression levels of Pol ι in 31 breast cancer tissues. Then the stable overexpression of Pol ι and knockdown of Pol ι breast cancer cell lines were constructed. Wound-healing assay and transwell assay were performed to evaluate cell migratory and invasiveness, respectively. Signaling pathway was analyzed by western blot.
RESULTS: The expression levels of Pol ι is overexpressed in breast cancer tissues and significantly higher in breast cancer tissues with lymph node metastasis compared to those without lymph node metastasis. Elevated Pol ι expression promoted migratory and invasiveness of breast cancer cells. Signaling pathway analysis indicated EGFR-ERK cascade works as a mediator of Pol ι-induced EMT of breast cancer cells.
CONCLUSIONS: These data demonstrate the underlying mechanism by which Pol ι promotes breast cancer progression, suggesting that Pol ι may be a potential therapeutic target against breast cancer.

Gambi G, Di Simone E, Basso V, et al.
The Transcriptional Regulator Sin3A Contributes to the Oncogenic Potential of STAT3.
Cancer Res. 2019; 79(12):3076-3087 [PubMed] Related Publications
Epigenetic silencing of promoter and enhancer regions is a common phenomenon in malignant cells. The transcription factor STAT3 is aberrantly activated in several tumors, where its constitutive acetylation accounts for the transcriptional repression of a number of tumor suppressor genes (TSG) via molecular mechanisms that remain to be understood. Using nucleophosmin-anaplastic lymphoma kinase-positive (NPM-ALK

Avalle L, Poli V
Nucleus, Mitochondrion, or Reticulum? STAT3 à La Carte.
Int J Mol Sci. 2018; 19(9) [PubMed] Free Access to Full Article Related Publications
The transcription factor signal transducer and activator of transcription (STAT)3 mediates the functions of cytokines, growth factors, and oncogenes under both physiological and pathological conditions. Uncontrolled/constitutive STAT3 activity is often detected in tumors of different types, where its role is mostly that of an oncogene, contributing in multiple ways to tumor transformation, growth, and progression. For this reason, many laboratories and pharmaceutical companies are making efforts to develop specific inhibitors. However, STAT3 has also been shown to act as a tumor suppressor in a number of cases, suggesting that its activity is strongly context-specific. Here, we discuss the bases that can explain the multiple roles of this factor in both physiological and pathological contexts. In particular, we focus on the following four features: (i) the distinct properties of the STAT3α and β isoforms; (ii) the multiple post-translational modifications (phosphorylation on tyrosine or serine, acetylation and methylation on different residues, and oxidation and glutathionylation) that can affect its activities downstream of multiple different signals; (iii) the non-canonical functions in the mitochondria, contributing to the maintenance of energy homeostasis under stress conditions; and (iv) the recently discovered functions in the endoplasmic reticulum, where STAT3 contributes to the regulation of calcium homeostasis, energy production, and apoptosis.

Li L, Tian H, Cheng C, et al.
siRNA of DNA polymerase iota inhibits the migration and invasion in the lung cancer cell A549.
Acta Biochim Biophys Sin (Shanghai). 2018; 50(9):929-933 [PubMed] Related Publications
DNA polymerase iota (polɩ) is a member of low-fidelity Y-family of DNA polymerases. Our previous studies have demonstrated that the overexpression of polι is associated with the poorer prognosis in lung cancer patients. Here, we designed the small interfering RNA (siRNA) targeting polɩ gene (POLI) to investigate the effect of polɩ on the proliferation, apoptosis, and invasion of the lung cancer cell line A549 in order to reveal the role of polι in lung cancer progression. Our results showed that siRNA of POLI had no significant effect on the proliferation and apoptosis of the lung cancer cell line A549. However, siRNA of POLI could inhibit the migration and invasion of the lung cancer cell line A549 by upregulating the E-cadherin expression and downregulating the expressions of N-cadherin, MMP2, and MMP9. Together, our findings indicate that polι plays a positive role in lung cancer progression via promoting the migration and invasion of lung cancer cells. Therefore, polι might be a potential target for the clinical treatment of lung cancer in the future.

Priego N, Zhu L, Monteiro C, et al.
STAT3 labels a subpopulation of reactive astrocytes required for brain metastasis.
Nat Med. 2018; 24(7):1024-1035 [PubMed] Related Publications
The brain microenvironment imposes a particularly intense selective pressure on metastasis-initiating cells, but successful metastases bypass this control through mechanisms that are poorly understood. Reactive astrocytes are key components of this microenvironment that confine brain metastasis without infiltrating the lesion. Here, we describe that brain metastatic cells induce and maintain the co-option of a pro-metastatic program driven by signal transducer and activator of transcription 3 (STAT3) in a subpopulation of reactive astrocytes surrounding metastatic lesions. These reactive astrocytes benefit metastatic cells by their modulatory effect on the innate and acquired immune system. In patients, active STAT3 in reactive astrocytes correlates with reduced survival from diagnosis of intracranial metastases. Blocking STAT3 signaling in reactive astrocytes reduces experimental brain metastasis from different primary tumor sources, even at advanced stages of colonization. We also show that a safe and orally bioavailable treatment that inhibits STAT3 exhibits significant antitumor effects in patients with advanced systemic disease that included brain metastasis. Responses to this therapy were notable in the central nervous system, where several complete responses were achieved. Given that brain metastasis causes substantial morbidity and mortality, our results identify a novel treatment for increasing survival in patients with secondary brain tumors.

Fagnocchi L, Poli V, Zippo A
Enhancer reprogramming in tumor progression: a new route towards cancer cell plasticity.
Cell Mol Life Sci. 2018; 75(14):2537-2555 [PubMed] Related Publications
Cancer heterogeneity arises during tumor progression as a consequence of genetic insults, environmental cues, and reversible changes in the epigenetic state, favoring tumor cell plasticity. The role of enhancer reprogramming is emerging as a relevant field in cancer biology as it supports adaptation of cancer cells to those environmental changes encountered during tumor progression and metastasis seeding. In this review, we describe the cancer-related alterations that drive oncogenic enhancer activity, leading to dysregulated transcriptional programs. We discuss the molecular mechanisms of both cis- and trans-factors in overriding the regulatory circuits that maintain cell-type specificity and imposing an alternative, de-regulated enhancer activity in cancer cells. We further comment on the increasing evidence which implicates stress response and aging-signaling pathways in the enhancer landscape reprogramming during tumorigenesis. Finally, we focus on the potential therapeutic implications of these enhancer-mediated subverted transcriptional programs, putting particular emphasis on the lack of information regarding tumor progression and the metastatic outgrowth, which still remain the major cause of mortality related to cancer.

Poli V, Fagnocchi L, Fasciani A, et al.
MYC-driven epigenetic reprogramming favors the onset of tumorigenesis by inducing a stem cell-like state.
Nat Commun. 2018; 9(1):1024 [PubMed] Free Access to Full Article Related Publications
Breast cancer consists of highly heterogeneous tumors, whose cell of origin and driver oncogenes are difficult to be uniquely defined. Here we report that MYC acts as tumor reprogramming factor in mammary epithelial cells by inducing an alternative epigenetic program, which triggers loss of cell identity and activation of oncogenic pathways. Overexpression of MYC induces transcriptional repression of lineage-specifying transcription factors, causing decommissioning of luminal-specific enhancers. MYC-driven dedifferentiation supports the onset of a stem cell-like state by inducing the activation of de novo enhancers, which drive the transcriptional activation of oncogenic pathways. Furthermore, we demonstrate that the MYC-driven epigenetic reprogramming favors the formation and maintenance of tumor-initiating cells endowed with metastatic capacity. This study supports the notion that MYC-driven tumor initiation relies on cell reprogramming, which is mediated by the activation of MYC-dependent oncogenic enhancers, thus establishing a therapeutic rational for treating basal-like breast cancers.

Poli G, Granchi C, Aissaoui M, et al.
Three-Dimensional Analysis of the Interactions between hLDH5 and Its Inhibitors.
Molecules. 2017; 22(12) [PubMed] Free Access to Full Article Related Publications
Inhibitors of human lactate dehydrogenase (

Bavelloni A, Ramazzotti G, Poli A, et al.
MiRNA-210: A Current Overview.
Anticancer Res. 2017; 37(12):6511-6521 [PubMed] Related Publications
microRNAs (miRNAs) are a group of highly conserved small non-coding RNAs that were found to enhance mRNA degradation or inhibit post-transcriptional translation. Accumulating evidence indicates that miRNAs contribute to tumorigenesis and cancer metastasis. microRNA-210 has been largely studied in the past several years and has been identified as a major miRNA induced under hypoxia. A variety of miR-210 targets have been identified pointing to its role, not only in mitochondrial metabolism, but also in angiogenesis, the DNA damage response, cell proliferation, and apoptosis. Based on earlier research findings, this review aims to provide a current overview on the involvement of miRNA-210 in biological processes and diseases.

He C, Wu S, Gao A, et al.
Phosphorylation of ETS-1 is a critical event in DNA polymerase iota-induced invasion and metastasis of esophageal squamous cell carcinoma.
Cancer Sci. 2017; 108(12):2503-2510 [PubMed] Free Access to Full Article Related Publications
An aberrantly elevated expression of DNA polymerase ι (Pol ι) is significantly associated with poor prognosis of patients with esophageal squamous cell carcinoma (ESCC), yet the mechanisms behind this phenomenon remain obscure. Based on the RNA-Seq transcriptome and real-time PCR analysis, we identified ETS-1 as a candidate gene involved in Pol ι-mediated progression of ESCC. Wound-healing and transwell assay indicated that downregulation of ETS-1 attenuates Pol ι-mediated invasiveness of ESCC. Signaling pathway analysis showed that Pol ι enhances ETS-1 phosphorylation at threonine-38 through the Erk signaling pathway in ESCC cells. Kaplan-Meier analysis, based on 93 clinical tissue samples, revealed that ETS-1 phosphorylation at threonine-38 is associated with poor prognosis of ESCC patients. The present study thus demonstrates that phosphorylation of ETS-1 is a critical event in the Pol ι-induced invasion and metastasis of ESCC.

Poli G, Cochetti G, Boni A, et al.
Characterization of inflammasome-related genes in urine sediments of patients receiving intravesical BCG therapy.
Urol Oncol. 2017; 35(12):674.e19-674.e24 [PubMed] Related Publications
BACKGROUND: Nowadays, the intravesical Bacillus Calmette-Guérin (BCG) instillation is the method of choice for the postsurgical treatment of high-grade nonmuscle-invasive bladder cancer , to reduce both recurrence rate and risk of progression. BCG is hypothesized to correct the immune system disequilibrium occurring during carcinogenesis, through an immunostimulation with detrimental effects for tumoral cells. Inflammation plays a crucial role in tumor progression. The deregulation of inflammasomes upon carcinogenesis underlines its importance both in physiologic and pathologic human conditions. Nucleotide oligomerization domain-like receptors (NLRs) are key components of this molecular platform and the increase in expression of some members of nucleotide oligomerization domain-like receptors family (NLRP3, NLRP4, NLRP9, and NLR family apoptosis inhibitory protein [NAIP]) in urothelial carcinoma was already demonstrated in our previous work. The first aim of the present work was to estimate whether these inflammasome-related genes show alterations during BCG instillations. The expression levels of NLRP3, NLRP4, NLRP9, and NAIP were assessed in the urine sediments from patients, which underwent surgery for superficial high-grade bladder cancer and further subjected to serial BCG instillations. The eventual association between NLR expression and recurrence was also evaluated. The expression of CK20 mRNA as confirmed marker of bladder cancer was also assayed.
METHODS: Urine were sampled from patients harboring high-grade superficial bladder cancer and treated postsurgically with weekly BCG instillations for 6 weeks (induction cycle, I). Urine sediments were processed and resulting RNA was reverse transcribed and used for amplification by real-time PCR.
RESULTS: After surgery, CK20 levels decreased significantly whereas NLRP4 and NLRP9 genes showed an increase. NLRP3 and NAIP remained substantially unmodified. CK20 mRNA decreased at the end of the induction cycle. NLRP3 did not show relevant modifications. The expression levels of NLRP4 and NLRP9 decreased significantly after 2 BCG administrations and remained substantially downregulated during the whole induction cycle. CK20 was higher in recurrence cases before BCG administration compared to the recurrence-free group, while no significant difference after BCG therapy was recorded. NLRP4 and NLRP9 were higher in patients with recurrence before BCG administration.
CONCLUSIONS: The study underlines the importance of NLRP4 and NLRP9 in urothelial carcinoma and if these preliminary data will be confirmed in larger cohort studies, the assessment of NLRP4 and NLRP9 expression levels could help to predict the BCG failure, playing a relevant role in decision making for early radical surgery.

Sangalli A, Orlandi E, Poli A, et al.
Sex-specific effect of RNASEL rs486907 and miR-146a rs2910164 polymorphisms' interaction as a susceptibility factor for melanoma skin cancer.
Melanoma Res. 2017; 27(4):309-314 [PubMed] Related Publications
The genetics of melanoma is complex and, in addition to environmental influences, numerous genes are involved or contribute toward melanoma predisposition. In this study, we evaluated the possible interaction between miR-146a and one of its putative targets ribonuclease L (RNASEL) in the risk of sporadic melanoma. Polymorphisms rs2910164 in miR-146a and rs486907 in the RNASEL gene have both independently been associated with the risk of different cancers, and an interaction between them has been observed in nonmelanoma skin cancer. Polymorphisms rs2910164 G/C and rs486907 A/G were genotyped by restriction fragment length polymorphism analysis in 304 sporadic melanoma patients and 314 control individuals. Genotype distribution between cases and controls for each of the two polymorphisms was compared using Fisher's exact test. Epistasis between the two polymorphisms was tested by a logistic regression model. In the present study, we observed a sex-specific effect of the miR-146a rs2910164 C allele restricted to individuals carrying the RNASEL rs486907 A allele as well. Men carrying this allelic combination have the highest risk of melanoma, whereas it seems to have no effect or even an opposite relationship to melanoma risk in the female population. The results reported in the present study suggest a sex-specific interaction between miR-146a and RNASEL genes in melanoma skin cancer susceptibility, and could account for possible discordant results in association studies when stratification according to sex is not performed.

Tombolan L, Poli E, Martini P, et al.
NELL1, whose high expression correlates with negative outcomes, has different methylation patterns in alveolar and embryonal rhabdomyosarcoma.
Oncotarget. 2017; 8(20):33086-33099 [PubMed] Free Access to Full Article Related Publications
Rhabdomyosarcoma (RMS), which represents the most frequent soft tissue sarcoma in pediatric populations, is classified into two major subtypes: embryonal RMS (ERMS) and alveolar RMS (ARMS). ARMS subtype, which shows greater aggressiveness and proneness to metastasis with respect to ERMS, are characterized, in about 75% of cases, by specific chromosomal translocations that involve PAX and FOXO1 genes. Many findings have demonstrated that PAX/FOXO1-positive ARMS have a worse prognosis than PAX/FOXO1-negative ones and that distinct molecular features characterize RMS with different gene fusion statuses. DNA methylation, which presently represents a challenging research area, is involved in the modulation of gene expression.We performed a genome-wide DNA methylation analysis using reduced-representation bisulfite sequencing (RRBS) in RMS samples and we found that fusion-positive alveolar and embryonal subgroups have different DNA methylation signatures and that ARMS fusion-positive subtypes are characterized by overall hypomethylation levels. While NELL1 was found to be hypomethylated and transcriptionally enhanced in RMS alveolar subtypes, high NELL1 expression levels, which proved to be correlated with negative RMS prognostic factors such as fusion status and histology (P < 0.0001), were found to discriminate between RMS patients with different outcomes (P < 0.05).In conclusion, our results demonstrated that different DNA methylation patterns distinguish between different RMS subgroups and they suggest that epigenetic signatures could be useful for risk stratification of patients.

Rossin D, Calfapietra S, Sottero B, et al.
HNE and cholesterol oxidation products in colorectal inflammation and carcinogenesis.
Free Radic Biol Med. 2017; 111:186-195 [PubMed] Related Publications
Consistent experimental data suggest the importance of inflammation-associated oxidative stress in colorectal cancer (CRC) pathogenesis. Inflammatory bowel disease with chronic intestinal inflammation is now considered a precancerous condition. Oxidative stress is an essential feature of inflammation. Activation of redox-sensitive pro-inflammatory cell signals and inflammatory mediators concur to establish a pro-tumoral environment. In this frame, lipid oxidation products, namely 4-hydroxynonenal and oxysterols, can be produced in big quantity so as to be able to exert their function as inducers of cell signaling pathways of proliferation and survival. Notably, an important source of these two compounds is represented by a high fat diet, which is undoubtedly a risk factor for inflammation and CRC development. Current evidence for the emerging implication of these two oxidized lipids in inflammation and CRC development is discussed in this review.

Oshima G, Stack ME, Wightman SC, et al.
Advanced Animal Model of Colorectal Metastasis in Liver: Imaging Techniques and Properties of Metastatic Clones.
J Vis Exp. 2016; (117) [PubMed] Free Access to Full Article Related Publications
Patients with a limited number of hepatic metastases and slow rates of progression can be successfully treated with local treatment approaches

Tombolan L, Poli E, Martini P, et al.
Global DNA methylation profiling uncovers distinct methylation patterns of protocadherin alpha4 in metastatic and non-metastatic rhabdomyosarcoma.
BMC Cancer. 2016; 16(1):886 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Rhabdomyosarcoma (RMS), which can be classified as embryonal RMS (ERMS) and alveolar RMS (ARMS), represents the most frequent soft tissue sarcoma in the pediatric population; the latter shows greater aggressiveness and metastatic potential with respect to the former. Epigenetic alterations in cancer include DNA methylation changes and histone modifications that influence overall gene expression patterns. Different tumor subtypes are characterized by distinct methylation signatures that could facilitate early disease detection and greater prognostic accuracy.
METHODS: A genome-wide approach was used to examine methylation patterns associated with different prognoses, and DNA methylome analysis was carried out using the Agilent Human DNA Methylation platform. The results were validated using bisulfite sequencing and 5-aza-2'deoxycytidine treatment in RMS cell lines. Some in vitro functional studies were also performed to explore the involvement of a target gene in RMS tumor cells.
RESULTS: In accordance with the Intergroup Rhabdomyosarcoma Study (IRS) grouping, study results showed that distinct methylation patterns distinguish RMS subgroups and that a cluster of protocadherin genes are hypermethylated in metastatic RMS. Among these, PCDHA4, whose expression was decreased by DNA methylation, emerged as a down-regulated gene in the metastatic samples. As PCDHA4-silenced cells have a significantly higher cell proliferation rate paralleled by higher cell invasiveness, PCDHA4 seems to behave as a tumor suppressor in metastatic RMS.
CONCLUSION: Study results demonstrated that DNA methylation patterns distinguish between metastatic and non-metastatic RMS and suggest that epigenetic regulation of specific genes could represent a novel therapeutic target that could enhance the efficiency of RMS treatments.

Zou S, Shang ZF, Liu B, et al.
DNA polymerase iota (Pol ι) promotes invasion and metastasis of esophageal squamous cell carcinoma.
Oncotarget. 2016; 7(22):32274-85 [PubMed] Free Access to Full Article Related Publications
DNA polymerase iota (Pol ι) is an error-prone DNA polymerase involved in translesion DNA synthesis (TLS) that contributes to the accumulation of DNA mutations. We recently showed that Pol ι is overexpressed in human esophageal squamous cell cancer (ESCC) tissues which promotes ESCC' progression. The present study was aimed at investigating the molecular mechanisms by which Pol ι enhances the invasiveness and metastasis of ESCC cells. We found that the expression of Pol ι is significantly higher in ESCCs with lymph node metastasis compared to those without lymph node metastasis. Kaplan-Meier analysis revealed an inverse correlation between Pol ι expression and patient prognosis. The expression levels of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9), two essential regulators of cells' invasiveness, were positively associated with Pol ι expression in ESCC tissues. Ectopic expression of Pol ι enhanced the motility and invasiveness of ESCC cells as evaluated by wound-healing and transwell assays, respectively. A xenograft nude mouse model showed that Pol ι promotes the colonization of ESCC cells in the liver, lung and kidney. Signaling pathway analysis identified the JNK-AP-1 cascade as a mediator of the Pol ι-induced increase in the expression of MMP-2/9 and enhancement of ESCC progression. These data demonstrate the underlying mechanism by which Pol ι promotes ESCC progression, suggesting that Pol ι is a potential novel prognostic biomarker and therapeutic target for ESCC.

Poli A, Billi AM, Mongiorgi S, et al.
Nuclear Phosphatidylinositol Signaling: Focus on Phosphatidylinositol Phosphate Kinases and Phospholipases C.
J Cell Physiol. 2016; 231(8):1645-55 [PubMed] Related Publications
Phosphatidylinositol (PI) metabolism represents the core of a network of signaling pathways which modulate many cellular functions including cell proliferation, cell differentiation, apoptosis, and membrane trafficking. An array of kinases, phosphatases, and lipases acts on PI creating an important number of second messengers involved in different cellular processes. Although, commonly, PI signaling was described to take place at the plasma membrane, many evidences indicated the existence of a PI cycle residing in the nuclear compartment of eukaryotic cells. The discovery of this mechanism shed new light on many nuclear functions, such as gene transcription, DNA modifications, and RNA expression. As these two PI cycles take place independently of one another, understanding how nuclear lipid signaling functions and modulates nuclear output is fundamental in the study of many cellular processes. J. Cell. Physiol. 231: 1645-1655, 2016. © 2015 Wiley Periodicals, Inc.

Poli E, Zhang J, Nwachukwu C, et al.
Molecular Subtype-Specific Expression of MicroRNA-29c in Breast Cancer Is Associated with CpG Dinucleotide Methylation of the Promoter.
PLoS One. 2015; 10(11):e0142224 [PubMed] Free Access to Full Article Related Publications
Basal-like breast cancer is a molecularly distinct subtype of breast cancer that is highly aggressive and has a poor prognosis. MicroRNA-29c (miR-29c) has been shown to be significantly down-regulated in basal-like breast tumors and to be involved in cell invasion and sensitivity to chemotherapy. However, little is known about the genetic and regulatory factors contributing to the altered expression of miR-29c in basal-like breast cancer. We here report that epigenetic modifications at the miR-29c promoter, rather than copy number variation of the gene, may drive the lower expression of miR-29c in basal-like breast cancer. Bisulfite sequencing of CpG sites in the miR-29c promoter region showed higher methylation in basal-like breast cancer cell lines compared to luminal subtype cells with a significant inverse correlation between expression and methylation of miR-29c. Analysis of primary breast tumors using The Cancer Genome Atlas (TCGA) dataset confirmed significantly higher levels of methylation of the promoter in basal-like breast tumors compared to all other subtypes. Furthermore, inhibition of CpG methylation with 5-aza-CdR increases miR-29c expression in basal-like breast cancer cells. Flourescent In Situ Hybridization (FISH) revealed chromosomal abnormalities at miR-29c loci in breast cancer cell lines, but with no correlation between copy number variation and expression of miR-29c. Our data demonstrated that dysregulation of miR-29c in basal-like breast cancer cells may be in part driven by methylation at CpG sites. Epigenetic control of the miR-29c promoter by epigenetic modifiers may provide a potential therapeutic target to overcome the aggressive behavior of these cancers.

Sowjanya AP, Rao M, Vedantham H, et al.
Correlation of plasma nitrite/nitrate levels and inducible nitric oxide gene expression among women with cervical abnormalities and cancer.
Nitric Oxide. 2016; 52:21-8 [PubMed] Related Publications
Cervical cancer is caused by infection with high risk human papillomavirus (HR-HPV). Inducible nitric oxide synthase (iNOS), a soluble factor involved in chronic inflammation, may modulate cervical cancer risk among HPV infected women. The aim of the study was to measure and correlate plasma nitrite/nitrate levels with tissue specific expression of iNOS mRNA among women with different grades of cervical lesions and cervical cancer. Tissue biopsy and plasma specimens were collected from 120 women with cervical neoplasia or cancer (ASCUS, LSIL, HSIL and invasive cancer) and 35 women without cervical abnormalities. Inducible nitric oxide synthase (iNOS) mRNA from biopsy and plasma nitrite/nitrate levels of the same study subjects were measured. Single nucleotide polymorphism (SNP) analysis was performed on the promoter region and Ser608Leu (rs2297518) in exon 16 of the iNOS gene. Differences in iNOS gene expression and plasma nitrite/nitrate levels were compared across disease stage using linear and logistic regression analysis. Compared to normal controls, women diagnosed with HSIL or invasive cancer had a significantly higher concentration of plasma nitrite/nitrate and a higher median fold-change in iNOS mRNA gene expression. Genotyping of the promoter region showed three different variations: A pentanucleotide repeat (CCTTT) n, -1026T > G (rs2779249) and a novel variant -1153T > A. These variants were associated with increased levels of plasma nitrite/nitrate across all disease stages. The higher expression of iNOS mRNA and plasma nitrite/nitrate among women with pre-cancerous lesions suggests a role for nitric oxide in the natural history of cervical cancer.

Poli G, Brancorsini S, Cochetti G, et al.
Expression of inflammasome-related genes in bladder cancer and their association with cytokeratin 20 messenger RNA.
Urol Oncol. 2015; 33(12):505.e1-7 [PubMed] Related Publications
BACKGROUND: Inflammation plays a crucial role in different stages of cancer development and has long been associated with various types of cancer. Strong associations between dysregulated inflammasome activity and human heritable and acquired inflammatory diseases highlight the importance of this pathway in the immune response. The inflammasome is a large complex of NOD-like receptors called NLRs and drives growth and progression of different tumors. The aim of the present study was the characterization of some NLR genes, NLRP3, NLRP4, NLRP9, and NAIP, in urine sediment of patients with bladder cancer. Cytokeratin 20 and survivin were used as confirmed markers of bladder cancer.
BASIC PROCEDURES: For this study, 3 groups of subjects were considered: patients harboring bladder cancer, subjects affected by bladder inflammation (CTR1), and healthy subjects (CTR0). Total RNA was extracted from urine sediments and resulting complementary DNA was used for amplification by real-time polymerase chain reaction. Results were stratified according to tumor stage, grade, and risk of progression and recurrence.
MAIN FINDINGS: The expression of cytokeratin 20 was always significantly higher in patients with bladder cancer when compared with that in both the tumor-free groups. NLRP3, NLRP4, NLRP9, and NAIP were overexpressed in patients with BCa when compared with that in CTR0. Stratification according to tumor stage, grade, and risk of recurrence and progression showed NLRP up-regulations in patients with early-stage cancer. NAIP was overexpressed in high-risk patients in comparison to CTR0 and in high-grade patients compared with CTR0 and CTR1.
PRINCIPAL CONCLUSIONS: These data are relevant to demonstrate the role of inflammasome in urothelial carcinoma, making NLR genes in urine sediment potential candidates for bladder cancer diagnosis.

Pencik J, Schlederer M, Gruber W, et al.
STAT3 regulated ARF expression suppresses prostate cancer metastasis.
Nat Commun. 2015; 6:7736 [PubMed] Free Access to Full Article Related Publications
Prostate cancer (PCa) is the most prevalent cancer in men. Hyperactive STAT3 is thought to be oncogenic in PCa. However, targeting of the IL-6/STAT3 axis in PCa patients has failed to provide therapeutic benefit. Here we show that genetic inactivation of Stat3 or IL-6 signalling in a Pten-deficient PCa mouse model accelerates cancer progression leading to metastasis. Mechanistically, we identify p19(ARF) as a direct Stat3 target. Loss of Stat3 signalling disrupts the ARF-Mdm2-p53 tumour suppressor axis bypassing senescence. Strikingly, we also identify STAT3 and CDKN2A mutations in primary human PCa. STAT3 and CDKN2A deletions co-occurred with high frequency in PCa metastases. In accordance, loss of STAT3 and p14(ARF) expression in patient tumours correlates with increased risk of disease recurrence and metastatic PCa. Thus, STAT3 and ARF may be prognostic markers to stratify high from low risk PCa patients. Our findings challenge the current discussion on therapeutic benefit or risk of IL-6/STAT3 inhibition.

Peron M, Lovisa F, Poli E, et al.
Understanding the Interplay between Expression, Mutation and Activity of ALK Receptor in Rhabdomyosarcoma Cells for Clinical Application of Small-Molecule Inhibitors.
PLoS One. 2015; 10(7):e0132330 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Receptor tyrosine kinases (RTKs) have a central role in cancer initiation and progression, since changes in their expression and activity potentially results in cell transformation. This concept is essential from a therapeutic standpoint, as clinical evidence indicates that tumours carrying deregulated RTKs are particularly susceptible to their activity but also to their inhibition. Rhabdomyosarcoma (RMS) is an aggressive childhood cancer where emerging therapies rely on the use kinase inhibitors, and among druggable kinases ALK represents a potential therapeutic target to commit efforts against. However, the functional relevance of ALK in RMS is not known, likewise the multi-component deregulated RTK profile to which ALK belongs.
METHODS: In this study we used RMS cell lines representative of the alveolar and embrional histotype and looked at ALK intracellular localization, activity and cell signalling.
RESULTS: We found that ALK was properly located at the plasma membrane of RMS cells, though in an unphosphorylated and inactive state due to intracellular tyrosine phosphatases (PTPases) activity. Indeed, increase of ALK phosphorylation was observed upon PTPase inhibition, as well as after ligand binding or protein overexpression. In these conditions, ALK signalling proceeded through the MAPK/ERK and PI3K/AKT pathways, and it was susceptible to ATP-competitive inhibitors exposure. However, drug-induced growth inhibition, cell cycle arrest and apoptosis did not correlate with ALK expression only, but relied also on the expression of other RTKs with akin drug binding affinity. Indeed, analysis of baseline and inducible RTK phosphorylation confirmed that RMS cells were susceptible to ALK kinase inhibitors even in the absence of the primary intended target, due to the presence of compensatory RTKs signalling pathways.
CONCLUSIONS: These data, hence, provided evidences of a potentially active role of ALK in RMS cells, but also suggest caution in considering ALK a major therapeutic target in this malignancy, particularly if expression and activity cannot be accurately determined.

Aoufouchi S, De Smet A, Delbos F, et al.
129-Derived Mouse Strains Express an Unstable but Catalytically Active DNA Polymerase Iota Variant.
Mol Cell Biol. 2015; 35(17):3059-70 [PubMed] Free Access to Full Article Related Publications
Mice derived from the 129 strain have a nonsense codon mutation in exon 2 of the polymerase iota (Polι) gene and are therefore considered Polι deficient. When we amplified Polι mRNA from 129/SvJ or 129/Ola testes, only a small fraction of the full-length cDNA contained the nonsense mutation; the major fraction corresponded to a variant Polι isoform lacking exon 2. Polι mRNA lacking exon 2 contains an open reading frame, and the corresponding protein was detected using a polyclonal antibody raised against the C terminus of the murine Polι protein. The identity of the corresponding protein was further confirmed by mass spectrometry. Although the variant protein was expressed at only 5 to 10% of the level of wild-type Polι, it retained de novo DNA synthesis activity, the capacity to form replication foci following UV irradiation, and the ability to rescue UV light sensitivity in Polι(-/-) embryonic fibroblasts derived from a new, fully deficient Polι knockout (KO) mouse line. Furthermore, in vivo treatment of 129-derived male mice with Velcade, a drug that inhibits proteasome function, stabilized and restored a substantial amount of the variant Polι in these animals, indicating that its turnover is controlled by the proteasome. An analysis of two xeroderma pigmentosum-variant (XPV) cases corresponding to missense mutants of Polη, a related translesion synthesis (TLS) polymerase in the same family, similarly showed a destabilization of the catalytically active mutant protein by the proteasome. Collectively, these data challenge the prevailing hypothesis that 129-derived strains of mice are completely deficient in Polι activity. The data also document, both for 129-derived mouse strains and for some XPV patients, new cases of genetic defects corresponding to the destabilization of an otherwise functional protein, the phenotype of which is reversible by proteasome inhibition.

Egidi MG, Cochetti G, Guelfi G, et al.
Stability Assessment of Candidate Reference Genes in Urine Sediment of Prostate Cancer Patients for miRNA Applications.
Dis Markers. 2015; 2015:973597 [PubMed] Free Access to Full Article Related Publications
We aimed at assessing the stability of candidate reference genes in urine sediments of men subjected to digital rectal examination for suspected prostate cancer (PCa). Two microRNAs (miR-191 and miR-25) and 1 small nucleolar RNA (SNORD48) were assayed in 35 post-DRE urine sediments of men with PCa and in 26 subjects with histologically confirmed benign prostatic hyperplasia (BPH). The stability of candidate reference genes was assessed through BestKeeper algorithm and equivalence test. miR-200b and miR-452 were used to test for the effect of normalization on target genes. Our results proved miR-191 to be the most stable gene, showing the lowest degree of variation and the highest stability value. miR-25 and SNORD48 values fell beyond the cutoff of acceptability. In conclusion, we recommend the use of miR-191 for normalization purposes in post-DRE urine sediments.

Farnedi A, Rossi S, Bertani N, et al.
Proteoglycan-based diversification of disease outcome in head and neck cancer patients identifies NG2/CSPG4 and syndecan-2 as unique relapse and overall survival predicting factors.
BMC Cancer. 2015; 15:352 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Tumour relapse is recognized to be the prime fatal burden in patients affected by head and neck squamous cell carcinoma (HNSCC), but no discrete molecular trait has yet been identified to make reliable early predictions of tumour recurrence. Expression of cell surface proteoglycans (PGs) is frequently altered in carcinomas and several of them are gradually emerging as key prognostic factors.
METHODS: A PG expression analysis at both mRNA and protein level, was pursued on primary lesions derived from 173 HNSCC patients from whom full clinical history and 2 years post-surgical follow-up was accessible. Gene and protein expression data were correlated with clinical traits and previously proposed tumour relapse markers to stratify high-risk patient subgroups.
RESULTS: HNSCC lesions were indeed found to exhibit a widely aberrant PG expression pattern characterized by a variable expression of all PGs and a characteristic de novo transcription/translation of GPC2, GPC5 and NG2/CSPG4 respectively in 36%, 72% and 71% on 119 cases. Importantly, expression of NG2/CSPG4, on neoplastic cells and in the intralesional stroma (Hazard Ratio [HR], 6.76, p = 0.017) was strongly associated with loco-regional relapse, whereas stromal enrichment of SDC2 (HR, 7.652, p = 0.007) was independently tied to lymphnodal infiltration and disease-related death. Conversely, down-regulated SDC1 transcript (HR, 0.232, p = 0.013) uniquely correlated with formation of distant metastases. Altered expression of PGs significantly correlated with the above disease outcomes when either considered alone or in association with well-established predictors of poor prognosis (i.e. T classification, previous occurrence of precancerous lesions and lymphnodal metastasis). Combined alteration of all three PGs was found to be a reliable predictor of shorter survival.
CONCLUSIONS: An unprecedented PG-based prognostic portrait is unveiled that incisively diversifies disease course in HNSCC patients beyond the currently known clinical and molecular biomarkers.

Grabner B, Schramek D, Mueller KM, et al.
Disruption of STAT3 signalling promotes KRAS-induced lung tumorigenesis.
Nat Commun. 2015; 6:6285 [PubMed] Free Access to Full Article Related Publications
STAT3 is considered to play an oncogenic role in several malignancies including lung cancer; consequently, targeting STAT3 is currently proposed as therapeutic intervention. Here we demonstrate that STAT3 plays an unexpected tumour-suppressive role in KRAS mutant lung adenocarcinoma (AC). Indeed, lung tissue-specific inactivation of Stat3 in mice results in increased Kras(G12D)-driven AC initiation and malignant progression leading to markedly reduced survival. Knockdown of STAT3 in xenografted human AC cells increases tumour growth. Clinically, low STAT3 expression levels correlate with poor survival and advanced malignancy in human lung AC patients with smoking history, which are prone to KRAS mutations. Consistently, KRAS mutant lung tumours exhibit reduced STAT3 levels. Mechanistically, we demonstrate that STAT3 controls NF-κB-induced IL-8 expression by sequestering NF-κB within the cytoplasm, thereby inhibiting IL-8-mediated myeloid tumour infiltration and tumour vascularization and hence tumour progression. These results elucidate a novel STAT3-NF-κB-IL-8 axis in KRAS mutant AC with therapeutic and prognostic relevance.

Poli G, Ceni E, Armignacco R, et al.
2D-DIGE proteomic analysis identifies new potential therapeutic targets for adrenocortical carcinoma.
Oncotarget. 2015; 6(8):5695-706 [PubMed] Free Access to Full Article Related Publications
Adrenocortical carcinoma (ACC) is a rare aggressive tumor with poor prognosis when metastatic at diagnosis. The tumor biology is still mostly unclear, justifying the limited specificity and efficacy of the anti-cancer drugs currently available. This study reports the first proteomic analysis of ACC by using two-dimensional-differential-in-gel-electrophoresis (2D-DIGE) to evaluate a differential protein expression profile between adrenocortical carcinoma and normal adrenal. Mass spectrometry, associated with 2D-DIGE analysis of carcinomas and normal adrenals, identified 22 proteins in 27 differentially expressed 2D spots, mostly overexpressed in ACC. Gene ontology analysis revealed that most of the proteins concurs towards a metabolic shift, called the Warburg effect, in adrenocortical cancer. The differential expression was validated by Western blot for Aldehyde-dehydrogenase-6-A1,Transferrin, Fascin-1,Lamin A/C,Adenylate-cyclase-associated-protein-1 and Ferredoxin-reductase. Moreover, immunohistochemistry performed on paraffin-embedded ACC and normal adrenal specimens confirmed marked positive staining for all 6 proteins diffusely expressed by neoplastic cells, compared with normal adrenal cortex.In conclusion, our preliminary findings reveal a different proteomic profile in adrenocortical carcinoma compared with normal adrenal cortex characterized by overexpression of mainly metabolic enzymes, thus suggesting the Warburg effect also occurs in ACC. These proteins may represent promising novel ACC biomarkers and potential therapeutic targets if validated in larger cohorts of patients.

Rizzo D, Chauzeix J, Trimoreau F, et al.
IgM peak independently predicts treatment-free survival in chronic lymphocytic leukemia and correlates with accumulation of adverse oncogenetic events.
Leukemia. 2015; 29(2):337-45 [PubMed] Related Publications
We examined the significance of IgM peaks in chronic lymphocytic leukemia (CLL), including its association with newly reported MYD88, BIRC3, NOTCH1 and SF3B1 mutations. A total of 27, 25, 41 and 57 patients with monoclonal IgM or IgG peaks (IgM and IgG groups), hypogammaglobulinemia (Hypo-γ group) and normal immunoglobulin serum levels (normal-γ group) were, respectively, included. IgM peaks were mainly associated with Binet stage C and the del(17p). Biased usage of IGHV3-48 was shared by both IgM and IgG groups. IGHV3-74 and IGHV4-39 gene rearrangements were specific for IgM and IgG peaks, respectively. SF3B1, NOTCH1, MYD88 and BIRC3 mutation frequencies were 12%, 4%, 2% and 2%, respectively, being over-represented in IgM, IgG and Hypo-γ groups for SF3B1, and being equal between normal-γ and IgM groups for MYD88. Overall, 76%, 87%, 49% and 42% of cases from IgM, IgG, Hypo-γ and normal-γ groups had at least one intermediate or poor prognosis genetic marker, respectively. By multivariate analysis, IgM peaks were associated with shorter treatment-free survival independently from any other univariate poor prognosis biological parameters, including IgG peaks, Hypo-γ, IGHV status, SF3B1 mutations, cytogenetics and lymphocytosis. Therefore, as with IgG peaks, IgM peaks aggravated the natural course of CLL, with increased accumulation of adverse genetic events.

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