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Cancer stem cells (CSCs) are a subpopulation of cancer cells endowed with high tumorigenic, chemoresistant and metastatic potential. Nongenetic mechanisms of acquired resistance are increasingly being discovered, but molecular insights into the evolutionary process of CSCs are limited. Here, we show that type I interferons (IFNs-I) function as molecular hubs of resistance during immunogenic chemotherapy, triggering the epigenetic regulator demethylase 1B (KDM1B) to promote an adaptive, yet reversible, transcriptional rewiring of cancer cells towards stemness and immune escape. Accordingly, KDM1B inhibition prevents the appearance of IFN-I-induced CSCs, both in vitro and in vivo. Notably, IFN-I-induced CSCs are heterogeneous in terms of multidrug resistance, plasticity, invasiveness and immunogenicity. Moreover, in breast cancer (BC) patients receiving anthracycline-based chemotherapy, KDM1B positively correlated with CSC signatures. Our study identifies an IFN-I → KDM1B axis as a potent engine of cancer cell reprogramming, supporting KDM1B targeting as an attractive adjunctive to immunogenic drugs to prevent CSC expansion and increase the long-term benefit of therapy.

BRAF-mutated melanoma relapsing after targeted therapies is an aggressive disease with unmet clinical need. Hence the need to identify novel combination therapies able to overcome drug resistance. miRNAs have emerged as orchestrators of non-genetic mechanisms adopted by melanoma cells to challenge therapies. In this context we previously identified a subset of oncosuppressor miRNAs downregulated in drug-resistant melanomas. Here we demonstrate that lipid nanoparticles co-encapsulating two of them, miR-199-5p and miR-204-5p, inhibit tumor growth both in vitro and in vivo in combination with target therapy and block the development of drug resistance. Mechanistically they act by directly reducing melanoma cell growth and also indirectly by hampering the recruitment and reprogramming of pro-tumoral macrophages. Molecularly, we demonstrate that the effects on macrophages are mediated by the dysregulation of a newly identified miR-204-5p-miR-199b-5p/CCL5 axis. Finally, we unveiled that M2 macrophages programs are molecular signatures of resistance and predict response to therapy in patients. Overall, these findings have strong translational implications to propose new combination therapies making use of RNA therapeutics for metastatic melanoma patients.

Caspase-8 is a cysteine protease that plays an essential role in apoptosis. Consistently with its canonical proapoptotic function, cancer cells may genetically or epigenetically downregulate its expression. Unexpectedly, Caspase-8 is often retained in cancer, suggesting the presence of alternative mechanisms that may be exploited by cancer cells to their own benefit. In this regard, we reported that Src tyrosine kinase, which is aberrantly activated in many tumors, promotes Caspase-8 phosphorylation on Tyrosine 380 (Y380) preventing its full activation. Here, we investigated the significance of Caspase-8 expression and of its phosphorylation on Y380 in glioblastoma, a brain tumor where both Caspase-8 expression and Src activity are often aberrantly upregulated. Transcriptomic analyses identified inflammatory response as a major target of Caspase-8, and in particular, NFκB signaling as one of the most affected pathways. More importantly, we could show that Src-dependent phosphorylation of Caspase-8 on Y380 drives the assembly of a multiprotein complex that triggers NFκB activation, thereby inducing the expression of inflammatory and pro-angiogenic factors. Remarkably, phosphorylation on Y380 sustains neoangiogenesis and resistance to radiotherapy. In summary, our work identifies a novel interplay between Src kinase and Caspase-8 that allows cancer cells to hijack Caspase-8 to sustain tumor growth.

Cancer stem cells (CSCs) are tumor subpopulations driving disease development, progression, relapse and therapy resistance, and their targeting ensures tumor eradication. CSCs display heterogeneous replication stress (RS), but the functionality/relevance of the RS response (RSR) centered on the ATR-CHK1 axis is debated. Here, we show that the RSR is efficient in primary CSCs from colorectal cancer (CRC-SCs), and describe unique roles for PARP1 and MRE11/RAD51. First, we demonstrated that PARP1 is upregulated in CRC-SCs resistant to several replication poisons and RSR inhibitors (RSRi). In these cells, PARP1 modulates replication fork speed resulting in low constitutive RS. Second, we showed that MRE11 and RAD51 cooperate in the genoprotection and mitosis execution of PARP1-upregulated CRC-SCs. These roles represent therapeutic vulnerabilities for CSCs. Indeed, PARP1i sensitized CRC-SCs to ATRi/CHK1i, inducing replication catastrophe, and prevented the development of resistance to CHK1i. Also, MRE11i + RAD51i selectively killed PARP1-upregulated CRC-SCs via mitotic catastrophe. These results provide the rationale for biomarker-driven clinical trials in CRC using distinct RSRi combinations.

Multiple myeloma (MM) is a hematologic malignancy produced by a clonal expansion of plasma cells and characterized by abnormal production and secretion of monoclonal antibodies. This pathology exhibits an enormous heterogeneity resulting not only from genetic alterations but also from several epigenetic dysregulations. Here we provide evidence that Che-1/AATF (Che-1), an interactor of RNA polymerase II, promotes MM proliferation by affecting chromatin structure and sustaining global gene expression. We found that Che-1 depletion leads to a reduction of “active chromatin” by inducing a global decrease of histone acetylation. In this context, Che-1 directly interacts with histones and displaces histone deacetylase class I members from them. Strikingly, transgenic mice expressing human Che-1 in plasma cells develop MM with clinical features resembling those observed in the human disease. Finally, Che-1 downregulation decreases BRD4 chromatin accumulation to further sensitize MM cells to bromodomain and external domain inhibitors. These findings identify Che-1 as a promising target for MM therapy, alone or in combination with bromodomain and external domain inhibitors.

Multiple myeloma (MM) is a hematologic malignancy produced by a clonal expansion of plasma cells and characterized by abnormal production and secretion of monoclonal antibodies. This pathology exhibits an enormous heterogeneity resulting not only from genetic alterations but also from several epigenetic dysregulations. Here we provide evidence that Che-1/AATF (Che-1), an interactor of RNA polymerase II, promotes MM proliferation by affecting chromatin structure and sustaining global gene expression. We found that Che-1 depletion leads to a reduction of “active chromatin” by inducing a global decrease of histone acetylation. In this context, Che-1 directly interacts with histones and displaces histone deacetylase class I members from them. Strikingly, transgenic mice expressing human Che-1 in plasma cells develop MM with clinical features resembling those observed in the human disease. Finally, Che-1 downregulation decreases BRD4 chromatin accumulation to further sensitize MM cells to bromodomain and external domain inhibitors. These findings identify Che-1 as a promising target for MM therapy, alone or in combination with bromodomain and external domain inhibitors.

Molecular characterization studies revealed recurrent kelch like ECH associated protein 1 gene (KEAP1)/nuclear factor, erythroid 2 like 2 gene (NFE2L2) alterations in NSCLC. These genes encode two interacting proteins (a stress response pathway [SRP]) that mediate a cytoprotective response to oxidative stress and xenobiotics. Nevertheless, whether KEAP1/NFE2L2mutations have an impact on clinical outcomes is unclear.

ABSTRACTB-cell precursor acute lymphoblastic leukemia (BCP-ALL) is the most common malignancy in childhood. Despite the high cure-rate, identifying new druggable molecular targets is still of great interest. In a cohort of BCP-ALL pediatric patients, irrespectively of the molecule/karyotype lesions found, we recently observed high expression of c-Myc and Che-1/AATF, which disappears at time of remission. Study of the molecular mechanisms involved in this co-expression revealed that Che-1 expression was crucial for induction of blast-cell proliferation driven by c-Myc. Furthermore, Che-1/AATF silencing in primary BCP-ALL cell lines improves responsiveness to chemotherapy. These data individuate Che-1 as a possible novel target in the treatment of BCP-ALL able to affect c-Myc-driven tumorigenicity.

A fundamental principle in malignant tranformation is the ability of cancer cells to escape the naturally occurring cell-intrinsic responses to DNA damage. Tumors progress despite the accumulation of DNA lesions. However, the underlying mechanisms of this tolerance to genotoxic stress are still poorly characterized. Here, we show that replication stress occurs in Kras-driven murine lung adenocarcinomas, as well as in proliferating murine embryonic and adult tissues. We identify the transcriptional regulator AATF/CHE-1 as a key molecule to sustain proliferative tissues and tumor progression in parts by inhibiting p53-driven apoptosis in vivo. In an autochthonous Kras-driven lung adenocarcinoma model, deletion of Aatfdelayed lung cancer formation predominantly in a p53-dependent manner. Moreover, targeting Aatfin existing tumors through a dual recombinase strategy caused a halt in tumor progression. Taken together, these data suggest that AATF may serve as a drug target to treat KRAS-driven malignancies.

ObjectiveCancer stem cells (CSCs) are responsible for tumour formation and spreading, and their targeting is required for tumour eradication. There are limited therapeutic options for advanced colorectal cancer (CRC), particularly for tumours carrying RAS-activating mutations. The aim of this study was to identify novel CSC-targeting strategies.DesignTo discover potential therapeutics to be clinically investigated as single agent, we performed a screening with a panel of FDA-approved or investigational drugs on primary CRC cells enriched for CSCs (CRC-SCs) isolated from 27 patients. Candidate predictive biomarkers of efficacy were identified by integrating genomic, reverse-phase protein microarray (RPPA) and cytogenetic analyses, and validated by immunostainings. DNA replication stress (RS) was increased by employing DNA replication-perturbing or polyploidising agents.ResultsThe drug-library screening led to the identification of LY2606368 as a potent anti-CSC agent acting in vitro and in vivo in tumour cells from a considerable number of patients (∼36%). By inhibiting checkpoint kinase (CHK)1, LY2606368 affected DNA replication in most CRC-SCs, including RAS-mutated ones, forcing them into premature, lethal mitoses. Parallel genomic, RPPA and cytogenetic analyses indicated that CRC-SCs sensitive to LY2606368 displayed signs of ongoing RS response, including the phosphorylation of RPA32 and ataxia telangiectasia mutated serine/threonine kinase (ATM). This was associated with mutation(s) in TP53and hyperdiploidy, and made these CRC-SCs exquisitely dependent on CHK1 function. Accordingly, experimental increase of RS sensitised resistant CRC-SCs to LY2606368.ConclusionsLY2606368 selectively eliminates replication-stressed, p53-deficient and hyperdiploid CRC-SCs independently of RASmutational status. These results provide a strong rationale for biomarker-driven clinical trials with LY2606368 in patients with CRC.

Che-1 is a nuclear protein involved in the regulation of gene transcription and cell proliferation. It has also been shown to localize to the cytoplasm of postmitotic neuronal cells, where it is able to interact with the microtubule-associated protein tau. Cyclin-dependent kinase 5 (Cdk5) is a postmitotic proline-directed serinethreonine kinase that hyperphosphorylates tau under pathological conditions. We observed that Che-1 overexpression induces Cdk5 expression both at the mRNA and protein levels. Furthermore, we show that Che-1 directly interacts with Cdk5 protein in vivo. Cdk5Che-1 complex formation does not compete with Cdk5p35 interaction, thus Che-1 is able to bind the active kinase complex. Finally, we demonstrated that Che-1 is itself a Cdk5 substrate.

hRPB11 is a core subunit of RNA polymerase II (pol II) specifically down‐regulated on doxorubicin (dox) treatment. Levels of this protein profoundly affect cell differentiation, cell proliferation, and tumorigenicity in vivo.Here we describe Che‐1, a novel human protein that interacts with hRPB11. Che‐1 possesses a domain of high homol‐ogy with Escherichia coliRNA polymerase σ‐factor 70 and SV40 large T antigen. In addition, we report that Che‐1 interacts with the retinoblastoma susceptibility gene (Rb) by two distinct domains. Functionally, we demonstrate that Che‐1 represses the growth suppression function of Rb, counteracting the inhibitory action of Rb on the irans‐activation function of E2F1. These results identify a novel protein that binds Rb and the core of pol II, and suggest that Che‐1 may be part of transcription regulatory complex.—Fanciulli, M., Bruno, T, Di Padova, M., De Angelis, R., Iezzi, S., Iacobini, C, Floridi, A., Passananti, C. Identification of a novel partner of RNA polymerase II subunit 11, Che‐1, which interacts with and affects the growth suppression function of Rb. FASEB J.14, 904–912 (2000)

We have previously cloned the human RNA polymerase II subunit 11, as a doxorubicin sensitive gene product. We suggested multiple tasks for this subunit, including structural and regulatory roles. With the aim to clarify the human RNA polymerase II subunit 11 function, we have identified its interacting protein partners using the yeast two‐hybrid system. Here, we show that human RNA polymerase II subunit 11 specifically binds keratin 19, a component of the intermediate filament protein family, which is expressed in a tissue and differentiation‐specific manner. In particular, keratin 19 is a part of the nuclear matrix intermediate filaments. We provide evidence that human RNA polymerase II subunit 11 interacts with keratin 19 via its N‐terminal α motif, the same motif necessary for its interaction with the human RNA polymerase II core subunit 3. We found that keratin 19 contains two putative leucine zipper domains sharing peculiar homology with the α motif of human RNA polymerase II subunit 3. Finally, we demonstrate that keratin 19 can compete for binding human RNA polymerase II subunit 11/human RNA polymerase II subunit 3 in vitro, suggesting a possible regulatory role for this molecule in RNA polymerase II assembly/activity.

Lonidamine (LND), a selective inhibitor of the energy metabolism of tumor cells, induces apoptosis, independently of the p53 gene, in the adriamycin(ADR)-resistant MCF7 breast-cancer cell line (MCF7 ADR). On the contrary, LND fails to activate the apoptotic program in the parental MCF7-sensitive cell line (MCF7 WT). The extent of bcl-2 expression might account for the different effect of LND on these cell lines. In fact, the MCF7 ADR line shows a low level of bcl-2 protein, whereas MCF7 WT expresses a high level of bcl-2. We therefore investigated the relationship between the amount of bcl-2 and the ability of LND to induce apoptosis, using 4 clones over-expressing bcl-2. The effect of bcl-2 on the energy metabolism was also evaluated. We demonstrated that over-expression of bcl-2 inhibited LND-induced apoptosis, while reducing ¹⁴CO2 production, oxygen uptake and ATP content, whereas aerobic lactate production was essentially unaffected. In addition, LND decreased the oxidative metabolism of the MCF7 ADR cells to a greater extent than it did in the bcl-2 transfectants. Int. J. Cancer 82:125–130, 1999. © 1999 Wiley-Liss, Inc.

On the basis of the recognition “code” that suggests specific rules between zinc finger's primary structure and the finger's potential DNA binding sites, we have constructed a new three-zinc finger coding gene to target the nine base pair DNA sequence: 5′-TGG-ATG-GAC-3′. This artificial gene named “Sint1” belongs to the Cys2-His2zinc finger type. The amino acid positions, crucial for DNA binding, have been specifically chosen on the basis of the amino acid/base contacts more frequently represented in the available list of the proposed recognition “code”. Here we demonstrate that Sint1 protein binds specifically the double strand “code” DNA target, with a dissociation constant (Kd) comparable to the Kd of the well known Zif268 protein. Sint1 “code” deduced and the “experimental” selected DNA binding sites share five nucleotide positions. Interestingly, Sint1 shows both high affinity and specificity toward the single strand “code” DNA binding site, with a Kd comparable to the corresponding double strand DNA target. Moreover, we prove that Sint1 is able to bind RNA similarly to several natural zinc finger proteins.

We previously isolated the human RPB11 cDNA, encoding the 13.3 kDa subunit of RNA polymerase II, and demonstrated that expression of this subunit is modulated by doxorubicin. Using hRPB11 as bait in a yeast two‐hybrid system, two cDNA variants encoding a second RNA polymerase II subunit, hRPB3, have now been isolated and characterized. These two hRPB3 mRNA species differed in 3′ UTR region length, the longer transcript containing the AU‐rich sequence motif that mediates mRNA degradation. Both hRPB11 and hRPB3 transcripts share a similar pattern of distribution in human adult tissues, with particularly high levels in both heart and skeletal muscle, and the expression of both is down‐regulated by doxorubicin as found previously for the hRPB11 subunit. Taken together, these findings suggest that the interaction between hRPB3 and hRPB11 is fundamental for their function and that this heterodimer is involved in doxorubicin toxicity.

We have previously shown that the human RNA polymerase II subunit 11 (hRPB11) is among the proteins specifically downregulated upon Doxorubicin (Dox) treatment of human cancer cell lines, and that Dox resistant clones derived upon drug selection express about 20% of the protein present in the original parental cell line. Given the prominent role that this subunit appears to have in eukaryotic cells, and the fact that its deletion causes lethality in yeast, we wanted to test the effect of the reintroduction of parental cell line levels of this subunit in Dox resistant colon cancer cells (LoVoDX). Stable transfectants of LoVoDX expressing parental (LoVoH) levels of hRPB11 showed a reduced sensitivity to the drug without changing the response of these cells to other chemotherapeutic agents, confirming a specific inverse correlation between cellular Dox sensitivity anti‐hRPB11 levels of expression. In addition we show here that the levels of expression of this same RNA polymerase II subunit directly affect cellular differentiation, reducing the rate of cell proliferation, clonogenicity and increasing the expression of E‐cadherin, a marker of epithelial cell differentiation. As expected from cells with these characteristics, upon in vivo administration of these clones in nude mice, we detected a significant reduction in the size and time of appearance of the primary tumors and overall metastatic capability. Finally, the role played by hRPB11 in regulating the transcription of specific genes is underlined by transient transfection experiments that show transactivation of the E‐cadherin promoter by this protein.

Lonidamine (LND) has been shown to inhibit tumor aerobic glycolysis. Its effect was evaluated on several human astrocytomas at different degrees of malignancy; a correlation was found between LDN effect on lactate production and tumor malignancy: in grade I and II astrocytomas LND stimulates lactate production, while in grade III, IV and glioblastoma multiforme lactate production is inhibited.

Using the differential display PCR method, we have isolated an mRNA downregulated in doxorubicin resistant human cell lines. The full length cDNA clone was identified as the human homologue of yeast RPB11 subunit of RNA polymerase II. Northern blot analysis of normal tissues detected a particularly high expression of RPB11 mRNA in heart and skeletal muscle. Reduction of this mRNA expression was observed in all the cell lines tested after drug treatment and was paralleled by a similar decrease of the protein levels. These findings suggest that doxorubicin may exert in vivo specific inhibitory effects on a major component of the transcription machinery.

The connection between driver mutations and efficacy of immune-checkpoint inhibitors (ICIs) is the focus of intense investigations. In lung adenocarcinoma (LUAD), KEAP1/STK11alterations have been tied to immunoresistance. Nevertheless, the heterogeneity characterizing immunotherapy efficacy suggests the contribution of still unappreciated events.

In 2009 the Istituto Regina Elena (IRE) and Istituto Dermopatico dell' Immacolata (IDI), joined their efforts to organize the “First IRE Annual Workshop on Chromatin Remodeling and Human Disease, which had place in Rome on the 3-4 of December 2009. The Workshop program listed a number of presentations on various epigenetic phenomena believed to have an impact on human diseases. Internationally recognized leaders in this field from Europe and USA have brilliantly accomplished this highly compelling task. Special emphasis has been placed on emerging understanding of epigenetic mechanisms as they relate to the physiopathology of numerous human diseases. How this field scientifically and technologically recently progressed in this direction, was clearly evident from the presentations and discussions having place during the workshop.

Che-1 is a RNA polymerase II binding protein involved in the transcriptional regulation of E2F target-genes and in cell proliferation. Recently, it has been shown that Che-1 accumulates in cells responding to genotoxic agents, such as Doxorubicin and ionizing radiations. The DNA damage-activated checkpoint kinases ATM and Chk2 interact with and phosphorylate Che-1, enhancing its accumulation and stability, and promoting Che-1-mediated transcription of p53-responsive genes and of p53 itself, as evidenced by microarray analysis. This transcriptional response is suppressed by expression of a Che-1 mutant lacking ATM and Chk2 phosphorylation amino acid residues, or by depletion of Che-1 by RNA silencing. In addition, chromatin immunoprecipitation analysis has shown that Che-1 is released from the E2F-target genes and recruited to the p21 and p53 promoters after DNA damage. Lastly, Che-1 contributes to the maintenance of the G2/M checkpoint in response to genotoxic stresses. These findings identify a new mechanism by which the checkpoint kinases regulate, via the novel effector Che-1, the p53 pathway.

RNA polymerase II core subunit 3 (RPB3) is an α‐like core subunit of RNA polymerase II (pol II). It is selectively down‐regulated upon treatment with doxorubicin (dox). Due to the failure of skeletal muscle cells to differentiate when exposed to dox, we hypothesized that RPB3 is involved in muscle differentiation. To this end, we have isolated human muscle RPB3interacting proteins by using yeast two‐hybrid screening. It is of interest that an interaction between RPB3 and the myogenic transcription factor myogenin was identified. This interaction involves a specific region of RPB3 protein that is not homologous to the prokaryotic α subunit. Although RPB3 contacts the basic helix‐loop‐helix (HLH) region of myogenin, it does not bind other HLH myogenic factors such as MyoD, Myf5, and MRF4. Coimmunoprecipitation experiments indicate that myogenin contacts the pol II complex and that the RPB3 subunit is responsible for this interaction. We show that RPB3 expression is regulated during muscle differentiation. Exogenous expression of RPB3 slightly promotes myogenin transactivation activity and muscle differentiation, whereas the region of RPB3 that contacts myogenin, when used as a dominant negative molecule (Sud), counteracts these effects. These results indicate for the first time that the RPB3 pol II subunit is involved in the regulation of tissue‐specific transcription.

ABSTRACTWhether PD-L1 expression is associated with survival outcomes in gastric cancer (GC) is controversial. The inhibition of the PD-1/PD-L1 pathway is effective against genomically unstable tumors. Hypothesizing that also the clinical significance of PD-L1 might be dependent on the activation of molecular circuits ensuring genomic stability, we evaluated PD-L1 expression in tissue samples from 72 advanced GC patients treated with first-line chemotherapy. Samples were already characterized for DNA damage repair (DDR) component expression (pATM, pChk1, pWee1, γ-H2AX and pRPA2) along with mutations in DDR-linked genes (TP53and ARID1A). Overall, PD-L1 expression was not associated with progression-free survival (PFS) and overall survival (OS), independently on whether we considered its expression in tumor cells (PD-L1-TCs) or in the immune infiltrate (PD-L1-TILs). In subgroup analysis, positive PD-L1-TC immunostaining was associated with better PFS in patients whose tumors did not carry DDR activation (multivariate Cox: HR 0.34, 95%CI: 0.15–0.76, p = 0.008). This subset (DDRoff) was characterized by negative pATM expression or the presence of ARID1Amutations. Conversely, the relationship between PD-L1-TC expression and PFS was lost in a molecular scenario denoting DDR activation (DDRon), as defined by concomitant pATM expression and ARID1Awild-type form. Surprisingly, while PD-L1-TC expression was associated with better OS in the DDRoffsubset (multivariate Cox: HR 0.41, 95% CI: 0.17–0.96, p = 0.039), in the DDRonsubgroup we observed an opposite impact on OS (multivariate Cox: HR 2.56, 95%CI: 1.06–6.16, p = 0.036). Thus, PD-L1-TC expression may impact survival outcomes in GC on the basis of the activation/inactivation of genome-safeguarding pathways.

No relevant conflicts of interest to declare.

Despite the overall progress in treatment of B-ALL, relapse occurs across the whole spectrum of all subtypes and has a dismal prognosis with an overall survival of 30%. This disease is typically characterized by genetic lesions resulting in oncogene activation, loss of tumor suppressor gene function and concurrent activation of pro-survival signaling pathways. The oncogene c-Myc is a master transcription factor governing many critical cell functions such as metabolism, proliferation and survival and it is involved in up to 70% of cancers. In Burkitt’s Lymphoma, c-Myc gene duplications or translocations have been described as leading to its constitutive transcriptional deregulation. Che-1/AATF is an important RNA polymerase II binding protein involved in the regulation of gene transcription. Che-1 is required for proliferation in early embryogenesis, and exhibits an anti-apoptotic activity in different tumour contests. Previous findings showed that Che-1 is over-expressed in different leukemic cell lines correlated with c-myc gene over-amplification, but, although it has been shown that Che-1 controls different mechanisms of tumorigenesis in several tumour contests, its role in haematological malignancies has not been deeply explored. With this aim we found a complete correlation of Che-1 and c-Myc expression in 80 B-ALL patients compared with 15 bone marrows from healthy donors lacking the expression of both molecules. These results are in agreement with public data derived from an RNAseq experiment on non-transgenic (control) and Eµ-myc transgenic littermates (pre-tumour), and in lymphomas arising in adult Eµ-myc animals (tumour), in which our analysis demonstrated that Che-1 mRNA levels increase during lymphomagenesis. In addition we observed a total ablation of Che-1 and c-Myc in the remission status, whereas samples from resistant or relapsed patients maintained high levels of both proteins. At the same time we observed that the down-regulation of c-Myc strongly reduces Che-1 mRNA and protein levels. Chip analysis revealed the ability of c-Myc to bind Che-1 promoter. Moreover, the two proteins also physically interact as demonstrated by co-immunoprecipitation experiments. We observed that Che-1 down-regulation induced growth arrest of B-ALL cell lines and affected the amount of ribosomal RNA by inhibiting the cooperation with UBF and RNA pol I. Based on these findings, by RNAseq analysis we compared the effect of Che-1 versus c-Myc downregulation finding a strong sharing of the controlled pathways. We demonstrated that Che-1 may be considered as a useful prognostic factor, able to early evaluate the aggressiveness of B-ALL. Furthermore the modulation of Che-1 expression may represent a strategy to improve treatment outcomes particularly in high-risk patient subgroups, wherein failure of conventional chemotherapy and relapse are common.