AMBRA1 regulates cyclin D to guard S-phase entry and genomic integrity.

Mammalian development, adult tissue homeostasis and the avoidance of severe diseases including cancer require a properly orchestrated cell cycle, as well as error-free genome maintenance. The key cell-fate decision to replicate the genome is controlled by two major signalling pathways that act in parallel-the MYC pathway and the cyclin D-cyclin-dependent kinase (CDK)-retinoblastoma protein (RB) pathway1,2. Both MYC and the cyclin D-CDK-RB axis are commonly deregulated in cancer, and this is associated with increased genomic instability. The autophagic tumour-suppressor protein AMBRA1 has been linked to the control of cell proliferation, but the underlying molecular mechanisms remain poorly understood. Here we show that AMBRA1 is an upstream master regulator of the transition from G1 to S phase and thereby prevents replication stress. Using a combination of cell and molecular approaches and in vivo models, we reveal that AMBRA1 regulates the abundance of D-type cyclins by mediating their degradation. Furthermore, by controlling the transition from G1 to S phase, AMBRA1 helps to maintain genomic integrity during DNA replication, which counteracts developmental abnormalities and tumour growth. Finally, we identify the CHK1 kinase as a potential therapeutic target in AMBRA1-deficient tumours. These results advance our understanding of the control of replication-phase entry and genomic integrity, and identify the AMBRA1-cyclin D pathway as a crucial cell-cycle-regulatory mechanism that is deeply interconnected with genomic stability in embryonic development and tumorigenesis.

HIPK2 controls cytokinesis and prevents tetraploidization by phosphorylating histone H2B at the midbody.

Failure in cytokinesis, the final step in cell division, by generating tetra- and polyploidization promotes chromosomal instability, a hallmark of cancer. Here we show that HIPK2, a kinase involved in cell fate decisions in development and response to stress, controls cytokinesis and prevents tetraploidization through its effects on histone H2B. HIPK2 binds and phosphorylates histone H2B at S14 (H2B-S14(P)), and the two proteins colocalize at the midbody. HIPK2 depletion by targeted gene disruption or RNA interference results in loss of H2B-S14(P) at the midbody, prevention of cell cleavage, and tetra- and polyploidization. In HIPK2 null cells, restoration of wild-type HIPK2 activity or expression of a phosphomimetic H2B-S14D derivative abolishes cytokinesis defects and rescues cell proliferation, showing that H2B-S14(P) is required for a faithful cytokinesis. Overall, our data uncover mechanisms of a critical HIPK2 function in cytokinesis and in the prevention of tetraploidization.

A "seasonal bromoderma" in a farmer.

Bromoderma is a rare skin disease caused by the ingestion, inhalation, or contact with products containing bromides. We report a case of bromoderma in a 36-year-old farmer, characterized by remission during the spring and exacerbation during the winter. The recognition of the use of products containing bromides during the winter helped us to understand the cause of the clinical condition.

Predictive Biomarkers for Checkpoint Inhibitor-Based Immunotherapy: The Galectin-3 Signature in NSCLCs.

Checkpoint inhibitor-based immunotherapy is opening a promising scenario in oncology, with objective responses registered in multiple cancer types. However, reliable predictive markers of tumor responsiveness are still lacking. These markers need to be urgently identified for a better selection of patients that can be candidates for immunotherapy. In this pilot study, a cohort of 34 consecutive patients bearing programmed death-ligand 1 (PD-L1)-positive non-small cell lung carcinoma (NSCLC), treated with pembrolizumab, was considered. The retrospective immuno-phenotypic analysis performed on the original tumor biopsies allowed for the identification of a specific "galectin signature", which strongly correlated with tumor responsiveness to anti PD-1 immunotherapy. We observed that the large majority of patients (about 90%) with high galectin-3 tumor expression (score 3+) showed an early and dramatic progression of the disease after three cycles of treatments. In contrast, all patients with negative or low/intermediate expression of galectin-3 in tumor cells showed an early and durable objective response to pembrolizumab, indicating galectin-3 as an interesting predictive marker of tumor responsiveness. The galectin-3 signature, at least in NSCLCs, promises a better selection of patient candidates for immunotherapy, reducing unnecessary treatment exposures and social costs. A large multicenter study is ongoing to validate this finding.

Loss of miR-204 expression is a key event in melanoma.

Cutaneous melanoma (CM) is a malignancy with increasing occurrence. Its microRNA repertoire has been defined in a number studies, leading to candidates for biological and clinical relevance: miR-200a/b/c, miR-203, miR-205, miR-204, miR-211, miR-23b and miR-26a/b. Our work was aimed to validate the role of these candidate miRNAs in melanoma, using additional patients cohorts and in vitro cultures. miR-26a, miR-204 and miR-211 were more expressed in normal melanocytes, while miR-23b, miR-200b/c, miR-203 and miR-205 in epidermis and keratinocytes. None of the keratinocyte-related miRNAs was associated with any known mutation or with clinical covariates in melanoma. On the other hand, the loss of miR-204 was enriched in melanomas with NRAS sole mutation (Fisher exact test, P = 0.001, Log Odds = 1.67), and less frequent than expected in those harbouring CDKN2A mutations (Fisher exact test, P = 0.001, Log Odds - 1.09). Additionally, miR-204 was associated with better prognosis in two independent melanoma cohorts and its exogenous expression led to growth impairment in melanoma cell lines. Thus, miR-204 represents a relevant mechanism in melanoma, with potential prognostic value and its loss seems to act in the CDKN2A pathway, in cooperation with NRAS.

The management of pseudomyogenic hemangioendothelioma of the foot: A case report and review of the literature.

Pseudomyogenic hemangioendothelioma (PMH) is a rare, mostly indolent, endothelial neoplasm of low-grade malignancy, often mimicking myoid and epithelioid tumors histologically. It is more frequent in young adult males and it usually presents with multiple cutaneous nodules, mostly localized at the extremities. It traverses several tissue planes simultaneously and can involve dermis, subcutis, skeletal muscle, and bone. Histologically, it is characterized by plump spindle cells with eosinophilic cytoplasm, often arranged in fascicles and epithelioid cells with "pseudomyogenic" morphology. Immunohistochemically, PMH is positive for Factor VIII, FLI-1, INI-1, vimentin, MDM2, CDK4, CD31, AE1/AE3, EMA, and P63. The efficacy of treatments is only partially known. Because of the frequent multifocal aspect of PMH, which contraindicates surgery, systemic treatments, such as gemcitabine, sirolimus, and everolimus are used. Based on our observation of multifocal PMH of the foot in a 17-year-old male patient, treated with gemcitabine with complete cutaneous response in a 2-year follow-up, we decided to discuss this rare tumor and underline its progression and therapeutic approaches. Thanks to a correct diagnosis, it is possible to avoid aggressive therapeutic approaches, which would be necessary for nonindolent diseases, such as sarcoma, which often needs amputation.

Galectin-3: The Impact on the Clinical Management of Patients with Thyroid Nodules and Future Perspectives.

Galectins (S-type lectins) are an evolutionarily-conserved family of lectin molecules, which can be expressed intracellularly and in the extracellular matrix, as well. Galectins bind ß-galactose-containing glycoconjugates and are functionally active in converting glycan-related information into cell biological programs. Altered glycosylation notably occurring in cancer cells and expression of specific galectins provide, indeed, a fashionable mechanism of molecular interactions able to regulate several tumor relevant functions, among which are cell adhesion and migration, cell differentiation, gene transcription and RNA splicing, cell cycle and apoptosis. Furthermore, several galectin molecules also play a role in regulating the immune response. These functions are strongly dependent on the cell context, in which specific galectins and related glyco-ligands are expressed. Thyroid cancer likely represents the paradigmatic tumor model in which experimental studies on galectins' glycobiology, in particular on galectin-3 expression and function, contributed greatly to the improvement of cancer diagnosis. The discovery of a restricted expression of galectin-3 in well-differentiated thyroid carcinomas (WDTC), compared to normal and benign thyroid conditions, contributed also to promoting preclinical studies aimed at exploring new strategies for imaging thyroid cancer in vivo based on galectin-3 immuno-targeting. Results derived from these recent experimental studies promise a further improvement of both thyroid cancer diagnosis and therapy in the near future. In this review, the biological role of galectin-3 expression in thyroid cancer, the validation and translation to a clinical setting of a galectin-3 test method for the preoperative characterization of thyroid nodules and a galectin-3-based immuno-positron emission tomography (immuno-PET) imaging of thyroid cancer in vivo are presented and discussed.

Discovery of chemotherapy-associated ovarian cancer antigens by interrogating memory T cells.

According to the immunogenic cell death hypothesis, clinical chemotherapy treatments may result in CD8(+) and CD4(+) T-cell responses against tumor cells. To discover chemotherapy-associated antigens (CAAs), T cells derived from ovarian cancer (OC) patients (who had been treated with appropriate chemotherapy protocols) were interrogated with proteins isolated from primary OC cells. We screened for immunogenicity using two-dimensional electrophoresis gel-eluted OC proteins. Only the selected immunogenic antigens were molecularly characterized by mass-spectrometry-based analysis. Memory T cells that recognized antigens associated with apoptotic (but not live) OC cells were correlated with prolonged survival in response to chemotherapy, supporting the model of chemotherapy-induced apoptosis as an adjuvant of anti-tumor immunity. The strength of both memory CD4(+) and CD8(+) T cells producing either IFN-γ or IL-17 in response to apoptotic OC antigens was also significantly greater in Responders to chemotherapy than in nonresponders. Immunogenicity of some of these antigens was confirmed using recombinant proteins in an independent set of patients. The T-cell interrogation system represents a strategy of reverse tumor immunology that proposes to identify CAAs, which may then be validated as possible prognostic tumor biomarkers or cancer vaccines.

Galectin-3 and cancer immunotherapy: a glycobiological rationale to overcome tumor immune escape.

Immunotherapy with checkpoint inhibitors (ICIs) has radically changed the landscape of therapeutic opportunities in oncology, but much still needs to be understood from a mechanistic point of view. There is space for further improving tumors' response to ICIs, as supported by a strong biological rationale. For this achievement a detailed analysis of tumor cell phenotype with functional dissection of the molecular interactions occurring in the TME is required. Galectin-3 is a pleiotropic tumor relevant molecule, which deserves particular attention in immuno-oncology. Due to its ability to finely modulate immune response in vivo, Galectin-3 is a potential target molecule to be considered for overcoming tumor immune escape.

Inactivation of HIPK2 attenuates KRASG12D activity and prevents pancreatic tumorigenesis.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) features KRAS mutations in approximately 90% of human cases and excessive stromal response, termed desmoplastic reaction. Oncogenic KRAS drives pancreatic carcinogenesis by acting on both epithelial cells and tumor microenvironment (TME). We have previously shown that Homeodomain-Interacting Protein Kinase 2 (HIPK2) cooperates with KRAS in sustaining ERK1/2 phosphorylation in human colorectal cancers. Here, we investigated whether HIPK2 contributes to oncogenic KRAS-driven tumorigenesis in vivo, in the onset of pancreatic cancer. METHODS: We employed an extensively characterized model of KRASG12D-dependent preinvasive PDAC, the Pdx1-Cre;LSL-KRasG12D/+ (KC) mice. In these mice, HIPK2 was inhibited by genetic knockout in the pancreatic epithelial cells (KCH-/-) or by pharmacologic inactivation with the small molecule 5-IodoTubercidin (5-ITu). The development of preneoplastic acinar-to-ductal metaplasia (ADM), intraepithelial neoplasia (PanIN), and their associated desmoplastic reaction were analyzed. RESULTS: In Hipk2-KO mice (KCH-/-), ERK phosphorylation was lowered, the appearance of ADM was slowed down, and both the number and pathologic grade of PanIN were reduced compared to Hipk2-WT KC mice. The pancreatic lesion phenotype in KCH-/- mice was characterized by abundant collagen fibers and reduced number of αSMA+ and pSTAT3+ desmoplastic cells. These features were reminiscent of the recently described human "deserted" sub-TME, poor in cells, rich in matrix, and associated with tumor differentiation. In contrast, the desmoplastic reaction of KC mice resembled the "reactive" sub-TME, rich in stromal cells and associated with tumor progression. These observations were confirmed by the pharmacologic inhibition of HIPK2 in KC mice. CONCLUSION: This study demonstrates that HIPK2 inhibition weakens oncogenic KRAS activity and pancreatic tumorigenesis providing a rationale for testing HIPK2 inhibitors to mitigate the incidence of PDAC development in high-risk individuals.

Repurposed AT9283 triggers anti-tumoral effects by targeting MKK3 oncogenic functions in Colorectal Cancer.

BACKGROUND: Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer-related deaths worldwide, with a survival rate near to 10% when diagnosed at an advanced stage. Hence, the identification of new molecular targets to design more selective and efficient therapies is urgently required. The Mitogen activated protein kinase kinase 3 (MKK3) is a dual-specificity threonine/tyrosine protein kinase that, activated in response to cellular stress and inflammatory stimuli, regulates a plethora of biological processes. Previous studies revealed novel MKK3 roles in supporting tumor malignancy, as its depletion induces autophagy and cell death in cancer lines of different tumor types, including CRC. Therefore, MKK3 may represent an interesting new therapeutic target in advanced CRC, however selective MKK3 inhibitors are currently not available. METHODS: The study involved transcriptomic based drug repurposing approach and confirmatory assays with CRC lines, primary colonocytes and a subset of CRC patient-derived organoids (PDO). Investigations in vitro and in vivo were addressed. RESULTS: The repurposing approach identified the multitargeted kinase inhibitor AT9283 as a putative compound with MKK3 depletion-mimicking activities. Indeed, AT9283 drops phospho- and total-MKK3 protein levels in tested CRC models. Likely the MKK3 silencing, AT9283 treatment: i) inhibited cell proliferation promoting autophagy and cell death in tested CRC lines and PDOs; ii) resulted well-tolerated by CCD-18Co colonocytes; iii) reduced cancer cell motility inhibiting CRC cell migration and invasion; iv) inhibited COLO205 xenograft tumor growth. Mechanistically, AT9283 abrogated MKK3 protein levels mainly through the inhibition of aurora kinase A (AURKA), impacting on MKK3/AURKA protein-protein interaction and protein stability therefore uncovering the relevance of MKK3/AURKA crosstalk in sustaining CRC malignancy in vitro and in vivo. CONCLUSION: Overall, we demonstrated that the anti-tumoral effects triggered by AT9283 treatment recapitulated the MKK3 depletion effects in all tested CRC models in vitro and in vivo, suggesting that AT9283 is a repurposed drug. According to its good tolerance when tested with primary colonocytes (CCD-18CO), AT9283 is a promising drug for the development of novel therapeutic strategies to target MKK3 oncogenic functions in late-stage and metastatic CRC patients.

Homeodomain-interacting protein kinase2 in human idiopathic pulmonary fibrosis.

Homeodomain-interacting protein kinase 2 (Hipk2) is an emerging player in cell response to genotoxic agents that contributes to the cell's decision between cell cycle arrest or apoptosis. HIPK2 acts as co-regulator of an increasing number of transcription factors and modulates many different basic cellular processes such as apoptosis, proliferation, DNA damage response, differentiation. Idiopathic pulmonary fibrosis (IPF) is characterized by an anatomical disarrangement of the lung due to fibroblast proliferation, extracellular matrix deposition and lung function impairment. Although the role of inflammation is still debated, attention has been focused on lung cell functions as fibroblast phenotype and activity. Aim of the present study was to analyze the loss of heterozygosity (LOH) at HIPK2 locus 7q32.34 in human lung fibroblasts and the HIPK2 expression in 15 IPF samples and in four primary fibroblast cell cultures isolated from IPF biopsies using semi-quantitative RT-PCR, Western blots and immunohistochemistry. We demonstrated a frequency of LOH in IPF fibroblasts of 46% for the internal D7S6440 microsatellite and 26.6% for the external D7S2468 microsatellite. Furthermore, we demonstrated low HIPK2 protein expression in those fibroblasts from IPF patients that present the HIPK2 LOH. The restoration of HIPK2 expression in IPF derived cells induced a significant reduction of chemoresistance after treatment with cisplatin. The results obtained allow us to hypothesize that HIPK2 dysfunction may play a role in fibroblasts behavior and in IPF pathogenesis. HIPK2 may be considered as a novel potential target for anti-fibrosis therapy.

Activated MKK3/MYC crosstalk impairs dabrafenib response in BRAFV600E colorectal cancer leading to resistance.

Colorectal cancer (CRC) patients with BRAF mutations develop resistance to BRAF inhibitors at a very early stage. Understanding the molecular mechanisms involved in BRAF inhibitor resistance is critical for the development of novel therapeutic opportunities for this subtype of CRC patients. CRC cells bearing BRAF mutations are mostly sensitive to the abrogation of Mitogen-Activated Protein Kinase Kinase 3 (MKK3), a specific activator of p38MAPKs signaling, suggesting that BRAF alterations might addict CRC cells to the MKK3/p38MAPK signaling. Interestingly, publicly available gene expression profiling data show significantly higher MKK3 transcript levels in CRC lines with acquired resistance to BRAF inhibitors. Herein, we investigated the roles of MKK3 in the response to BRAF targeting (dabrafenib) with COLO205 and HT29 BRAFV600E CRC lines and derived dabrafenib-resistant (DABR) sublines. Dabrafenib treatments reduce MKK3 activation by inducing autophagy in parental but not DABR cells. The MKK3 knockdown induces cell death in DABR cells, whereas ectopic MKK3 expression reduces dabrafenib sensitivity in parental cells. Mechanistically, activated MKK3 interacts and co-localizes with c-Myc oncoprotein (MYC), sustaining MYC protein stability and thus preventing the dabrafenib induced effects in CRC DABR cells both in vitro and in vivo. Overall, we identify a novel molecular mechanism beyond the dabrafenib resistance, shedding light on an uncovered vulnerability for the development of novel therapeutic opportunities in BRAFV600E CRC.

Renal cell carcinoma diagnosed by cutaneous metastasis: a case report.

Renal cell carcinoma (RCC) is one of the most frequent malignancies of the genitourinary tract and has the poorest prognosis of all urologic tumors. It often causes metastatic lesions, and although rare, the skin also can be involved. Cutaneous lesions rarely are the primary signs of RCC. We report a case of RCC with solitary nodular cutaneous metastasis on the right forearm that was seen before the primary tumor was diagnosed; there was no other organ involvement.

In Vivo Imaging of Thyroid Cancer with 99mTc-TR1401 and 99mTc-TR1402: A Comparison Study in Dogs.

Differentiated thyroid cancer (DTC) cells may lose NIS expression and iodine uptake, but usually express TSH receptors (TSHR). Therefore, the aim of our study was to compare two radiolabeled superagonist TSH analogues for DTC imaging. These analogues (namely TR1401 and TR1402) have a higher TSHR binding affinity than recombinant human TSH (Thyrogen®). Radiolabeling was performed with technetium-99m using an indirect method via HYNIC conjugation and was followed by in vitro quality controls and binding assay on TSHR-positive cell lines (ML-1). An in vitro binding assay was also performed and compared with radiolabeled human recombinant TSH. In vivo imaging was performed in four dogs with spontaneous follicular thyroid carcinoma with solid poorly differentiated areas with 99mTc-TR1401 SPECT/CT, 99mTc-TR1402 SPECT/CT, and [18F]FDG PET/CT on different days within 2 weeks. TR1401 and TR1402 were labeled with high specific activity (8.3 ± 1.2 MBq/µg) and retention of their biological activity and structural integrity. Both agonists were able to efficiently bind TSHR receptors expressed by cell lines with dissociation constants (Kd) of 2.7 nM for 99mTc-TR1401 and 0.5 nM for 99mTc-TR1402 compared with 99mTc-Thyrogen (Kd = 8.4 nM). In tumor-targeting experiments, a focal uptake was observed in dogs with spontaneous intraglandular thyroid carcinoma, in which TSHR expression was confirmed by immunohistochemistry. 99mTc-TR1402 provided higher T/B than 99mTc-TR1401 and [18F]FDG (12.9 ± 1.3, 10.2 ± 0.7, and 3.8 ± 0.6, respectively; all p < 0.001). Given these results, 99mTc-TR1402 appears to be a useful tool for in vivo imaging of thyroid cancer.

Effective rational humanization of a PASylated anti-galectin-3 Fab for the sensitive PET imaging of thyroid cancer in vivo.

The lack of a non-invasive test for malignant thyroid nodules makes the diagnosis of thyroid cancer (TC) challenging. Human galectin-3 (hGal3) has emerged as a promising target for medical TC imaging and diagnosis because of its exclusive overexpression in malignant thyroid tissues. We previously developed a human-chimeric αhGal3 Fab fragment derived from the rat monoclonal antibody (mAb) M3/38 with optimized clearance characteristics using PASylation technology. Here, we describe the elucidation of the hGal3 epitope recognized by mAb M3/38, X-ray crystallographic analysis of its complex with the chimeric Fab and, based on the three-dimensional structure, the rational humanization of the Fab by CDR grafting. Four CDR-grafted versions were designed using structurally most closely related fully human immunoglobulin VH/VL regions of which one-employing the acceptor framework regions of the HIV-1 neutralizing human antibody m66-showed the highest antigen affinity. By introducing two additional back-mutations to the rodent donor sequence, an affinity toward hGal3 indistinguishable from the chimeric Fab was achieved (KD = 0.34 ± 0.02 nM in SPR). The PASylated humanized Fab was site-specifically labelled with the fluorescent dye Cy7 and applied for the immuno-histochemical staining of human tissue sections representative for different TCs. The same protein was conjugated with the metal chelator Dfo, followed by radiolabelling with 89Zr(IV). The resulting protein tracer allowed the highly sensitive and specific PET/CT imaging of orthotopic tumors in mice, which was confirmed by quantitative analysis of radiotracer accumulation. Thus, the PASylated humanized αhGal3 Fab offers clinical potential for the diagnostic imaging of TC.