Immunotherapy in melanoma: advances, pitfalls, and future perspectives.

Cutaneous melanoma is the deadliest and most aggressive form of skin cancer owing to its high capacity for metastasis. Over the past few decades, the management of this type of malignancy has undergone a significant revolution with the advent of both targeted therapies and immunotherapy, which have greatly improved patient quality of life and survival. Nevertheless, the response rates are still unsatisfactory for the presence of side effects and development of resistance mechanisms.

HAX1 is a novel binding partner of Che-1/AATF. Implications in oxidative stress cell response.

HAX1 is a multifunctional protein involved in the antagonism of apoptosis in cellular response to oxidative stress. In the present study we identified HAX1 as a novel binding partner for Che-1/AATF, a pro-survival factor which plays a crucial role in fundamental processes, including response to multiple stresses and apoptosis. HAX1 and Che-1 proteins show extensive colocalization in mitochondria and we demonstrated that their association is strengthened after oxidative stress stimuli.

AATF/Che-1 RNA polymerase II binding protein overexpression reduces the anti-tumor NK-cell cytotoxicity through activating receptors modulation.

Introduction: AATF/Che-1 over-expression in different tumors is well known and its effect on tumorigenicity is mainly due to its central role demonstrated in the oncogenic pathways of solid tumors, where it controls proliferation and viability. The effect exerted by tumors overexpressing Che-1 on the immune response has not yet been investigated.

Methods: Starting from ChIP-sequencing data we confirmed Che-1 enrichment on Nectin-1 promoter.

CK2-mediated phosphorylation of Che-1/AATF is required for its pro-proliferative activity.

Background: Che-1/AATF (Che-1) is an RNA polymerase II binding protein involved in several cellular processes, including proliferation, apoptosis and response to stress. We have recently demonstrated that Che-1 is able to promote cell proliferation by sustaining global histone acetylation in multiple myeloma (MM) cells where it interacts with histone proteins and competes with HDAC class I members for binding.

Methods: Site-directed Mutagenesis was performed to generate a Che-1 mutant (Che-1 3S) lacking three serine residues (Ser, Ser and Ser) in 308-325 aa region.

Che-1/AATF-induced transcriptionally active chromatin promotes cell proliferation in multiple myeloma.

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.

Che-1/AATF binds to RNA polymerase I machinery and sustains ribosomal RNA gene transcription.

Originally identified as an RNA polymerase II interactor, Che-1/AATF (Che-1) has now been recognized as a multifunctional protein involved in cell-cycle regulation and cancer progression, as well as apoptosis inhibition and response to stress. This protein displays a peculiar nucleolar localization and it has recently been implicated in pre-rRNA processing and ribosome biogenesis. Here, we report the identification of a novel function of Che-1 in the regulation of ribosomal RNA (rRNA) synthesis, in both cancer and normal cells.

Che-1 is targeted by c-Myc to sustain proliferation in pre-B-cell acute lymphoblastic leukemia.

Despite progress in treating B-cell precursor acute lymphoblastic leukemia (BCP-ALL), disease recurrence remains the main cause of treatment failure. New strategies to improve therapeutic outcomes are needed, particularly in high-risk relapsed patients. Che-1/AATF (Che-1) is an RNA polymerase II-binding protein involved in proliferation and tumor survival, but its role in hematological malignancies has not been clarified.

Che-1 sustains hypoxic response of colorectal cancer cells by affecting Hif-1α stabilization.

Background: Solid tumours are less oxygenated than normal tissues. Consequently, cancer cells acquire to be adapted to a hypoxic environment. The poor oxygenation of solid tumours is also a major indicator of an adverse cancer prognosis and leads to resistance to conventional anticancer treatments.

Deptor transcriptionally regulates endoplasmic reticulum homeostasis in multiple myeloma cells.

Multiple myeloma (MM) is a malignant disorder of plasma cells characterized by active production and secretion of monoclonal immunoglobulins (IgG), thus rendering cells prone to endoplasmic reticulum (ER) stress. For this reason, MM cell survival requires to maintain ER homeostasis at basal levels. Deptor is an mTOR binding protein, belonging to the mTORC1 and mTORC2 complexes.

Che-1/AATF: A Critical Cofactor for Both Wild-Type- and Mutant-p53 Proteins.

The p53 protein is a key player in a wide range of protein networks that allow the state of "good health" of the cell. Not surprisingly, mutations of the TP53 gene are one of the most common alterations associated to cancer cells. Mutated forms of p53 (mtp53) not only lose the ability to protect the integrity of the genetic heritage of the cell but also acquire pro-oncogenic functions, behaving like dangerous accelerators of transformation and tumor progression.

Discovering Che-1/AATF: a new attractive target for cancer therapy.

The transcriptional cofactor Che-1/AATF is currently emerging as an important component of the DNA damage response (DDR) machinery, the complex signaling network that maintains genome integrity and prevents tumorigenesis. Moreover this protein is involved in a wide range of cellular pathways, regulating proliferation and survival in both physiological and pathological conditions. Notably, some evidence indicates that dysregulation of Che-1/AATF levels are associated with the transformation process and elevated levels of Che-1/AATF are required for tumor cell survival.

Che-1-induced inhibition of mTOR pathway enables stress-induced autophagy.

Mammalian target of rapamycin (mTOR) is a key protein kinase that regulates cell growth, metabolism, and autophagy to maintain cellular homeostasis. Its activity is inhibited by adverse conditions, including nutrient limitation, hypoxia, and DNA damage. In this study, we demonstrate that Che-1, a RNA polymerase II-binding protein activated by the DNA damage response, inhibits mTOR activity in response to stress conditions.

Centrosomal Che-1 protein is involved in the regulation of mitosis and DNA damage response by mediating pericentrin (PCNT)-dependent Chk1 protein localization.

To combat threats posed by DNA damage, cells have evolved mechanisms, collectively termed DNA damage response (DDR). These mechanisms detect DNA lesions, signal their presence, and promote their repair. Centrosomes integrate G2/M checkpoint control and repair signals in response to genotoxic stress, acting as an efficient control mechanism when G2/M checkpoint function fails and mitosis begins in the presence of damaged DNA.

Che-1 promotes tumor cell survival by sustaining mutant p53 transcription and inhibiting DNA damage response activation.

Che-1 is a RNA polymerase II binding protein involved in the regulation of gene transcription and, in response to DNA damage, promotes p53 transcription. In this study, we investigated whether Che-1 regulates mutant p53 expression. We found that Che-1 is required for sustaining mutant p53 expression in several cancer cell lines, and that Che-1 depletion by siRNA induces apoptosis both in vitro and in vivo.

NRAGE associates with the anti-apoptotic factor Che-1 and regulates its degradation to induce cell death.

Neurotrophin receptor-interacting MAGE homolog (NRAGE) has been recently identified as a cell-death inducer, involved in molecular events driving cells through apoptotic networks during neuronal development. Recently, we have focused on the functional role of Che-1, also known as apoptosis-antagonizing transcription factor (AATF), a protein involved in cell cycle control and gene transcription. Increasing evidence suggests that Che-1 is involved in apoptotic signalling in neural tissues.

The prolyl isomerase Pin1 affects Che-1 stability in response to apoptotic DNA damage.

We have previously demonstrated that DNA damage leads to stabilization and accumulation of Che-1, an RNA polymerase II-binding protein that plays an important role in transcriptional activation of p53 and in maintenance of the G(2)/M checkpoint. Here we show that Che-1 is down-regulated during the apoptotic process. We found that the E3 ligase HMD2 physically and functionally interacts with Che-1 and promotes its degradation via the ubiquitin-dependent proteasomal system.

Che-1 phosphorylation by ATM/ATR and Chk2 kinases activates p53 transcription and the G2/M checkpoint.

Che-1 is a RNA polymerase II-binding protein involved in the transcription of E2F target genes and induction of cell proliferation. Here we show that Che-1 contributes to DNA damage response and that its depletion sensitizes cells to anticancer agents. The checkpoint kinases ATM/ATR and Chk2 interact with Che-1 and promote its phosphorylation and accumulation in response to DNA damage.

Deacetylase inhibitors increase muscle cell size by promoting myoblast recruitment and fusion through induction of follistatin.

Fusion of undifferentiated myoblasts into multinucleated myotubes is a prerequisite for developmental myogenesis and postnatal muscle growth. We report that deacetylase inhibitors favor the recruitment and fusion of myoblasts into preformed myotubes. Muscle-restricted expression of follistatin is induced by deacetylase inhibitors and mediates myoblast recruitment and fusion into myotubes through a pathway distinct from those utilized by either IGF-1 or IL-4.

Sir2 regulates skeletal muscle differentiation as a potential sensor of the redox state.

Sir2 is a NAD(+)-dependent histone deacetylase that controls gene silencing, cell cycle, DNA damage repair, and life span. Prompted by the observation that the [NAD(+)]/[NADH] ratio is subjected to dynamic fluctuations in skeletal muscle, we have tested whether Sir2 regulates muscle gene expression and differentiation. Sir2 forms a complex with the acetyltransferase PCAF and MyoD and, when overexpressed, retards muscle differentiation.

Functional interaction of the subunit 3 of RNA polymerase II (RPB3) with transcription factor-4 (ATF4).

RPB3 is a core subunit of RNA polymerase II (pol II) that, together with the RPB11 subunit, forms the heterodimer considered as a functional counterpart of the bacterial alpha subunit homodimer involved in promoter recognition. We previously employed the yeast two-hybrid system and identified an interaction between RPB3 and the myogenic transcription factor myogenin, demonstrating an involvement of this subunit in muscle differentiation. In this paper we report the interaction between RPB3 and another known transcription factor, ATF4.

Che-1 arrests human colon carcinoma cell proliferation by displacing HDAC1 from the p21WAF1/CIP1 promoter.

Che-1 is a recently identified human RNA polymerase II binding protein involved in the regulation of gene transcription and cell proliferation. We previously demonstrated that Che-1 inhibits the Rb growth-suppressing function by interfering with Rb-mediated HDAC1 recruitment on E2F target gene promoters. By hybridization of cancer profile arrays, we found that Che-1 expression is strongly down-regulated in several tumors, including colon and kidney carcinomas, compared with the relative normal tissues.

The alpha-like RNA polymerase II core subunit 3 (RPB3) is involved in tissue-specific transcription and muscle differentiation via interaction with the myogenic factor myogenin.

RNA polymerase II core subunit 3 (RPB3) is an a-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.

Stage-specific modulation of skeletal myogenesis by inhibitors of nuclear deacetylases.

Nuclear acetyltransferases promote and deacetylases inhibit skeletal muscle-gene expression, suggesting the potential effectiveness of deacetylase inhibitors (DIs) in modulating skeletal myogenesis. Surprisingly, previous studies have indicated that DIs suppress myogenesis. The recent observations that histone deacetylases associate with the muscle-regulatory proteins MyoD and MEF2C only in undifferentiated myoblasts prompted us to evaluate the effect of DIs at distinct stages of the myogenic program.

Slug is a novel downstream target of MyoD. Temporal profiling in muscle regeneration.

Temporal expression profiling was utilized to define transcriptional regulatory pathways in vivo in a mouse muscle regeneration model. Potential downstream targets of MyoD were identified by temporal expression, promoter data base mining, and gel shift assays; Slug and calpain 6 were identified as novel MyoD targets. Slug, a member of the snail/slug family of zinc finger transcriptional repressors critical for mesoderm/ectoderm development, was further shown to be a downstream target by using promoter/reporter constructs and demonstration of defective muscle regeneration in Slug null mice.