the abc subfamily a transporters multifaceted players with incipient potentialities in cancer

Abstract Overexpression of ATP-binding cassette (ABC) transporters is a cause of drug resistance in a plethora of tumors. More recent evidence indicates additional contribution of these transporters to other processes, such as tumor cell dissemination and metastasis, thereby extending their possible roles in tumor progression. While the role of some ABC transporters, such as ABCB1, ABCC1 and ABCG2, in multidrug resistance is well documented, the mechanisms by which ABC transporters affect the proliferation, differentiation, migration and invasion of cancer cells are still poorly defined and are frequently controversial. This review, summarizes recent advances that highlight the role of subfamily A members in cancer. Emerging evidence highlights the potential value of ABCA members as biomarkers of risk and response in different tumors, but information is disperse and very little is known about their possible mechanisms of action. The only clear evidence is that ABCA members are involved in lipid metabolism and homeostasis. In particular, the relationship between ABCA1 and cholesterol is becoming evident in different fields of biology, including cancer. In parallel, emerging findings indicate that cholesterol, the main component of cell membranes, can influence many physiological and pathological processes, including cell migration, cancer progression and metastasis. This review aims to link the dispersed knowledge regarding the relationship of ABCA members with lipid metabolism and cancer in an effort to stimulate and guide readers to areas that the writers consider to have significant impact and relevant potentialities

RESEARCH OF PREDICTIVE AND PROGNOSTIC TISSUE AND MOLECULAR MARKERS AND OF NEW THERAPEUTIC TARGETS IN MALIGNANT PLEURAL MESOTHELIOMA

BACKGROUND: Malignant pleural mesothelioma (MPM) is an aggressive tumor with increasing incidence in industrialized countries, because of previous widespread asbestos exposure and long latency time before symptoms appearance. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) belongs to the tumor necrosis factor (TNF) family of death ligands; it was identified as a promising anticancer agent thanks to its property of killing cancer cells while sparing normal cells. Conflicting evidences about MPM resistance rather than sensitivity to TRAIL-induced apoptosis were previously reported. While TRAIL-dependent apoptosis is thought to be p53-independent, p53 wild type cancer cells can be sensitized to TRAIL through p53 activation. In contrast to most solid tumors, MPM cells frequently express wild type p53, thus p53 reactivation might be considered as an effective strategy to sensitize MPM cells to TRAIL-dependent apoptosis. DNA-damaging agents such as chemotherapy or radiotherapy and other agents targeting negative regulators of p53, may be considered as useful strategies to reactivate p53. Murine Double Minute 2 (MDM2) is a transcriptional target of p53: once activated, MDM2 binds p53 to the amino-terminus, targeting it for ubiquitylation and subsequent proteasomal degradation. Recently, many researchers have investigated a possible role of MDM2 in promoting tumor neoangiogenesis (Vascular Endothelial Growth Factor, VEGF; hypoxia inducible factor, HIF1alpha). Thus MDM2 might be a promising target for anticancer treatment because of its antiapoptotic and proangiogenetic role. The poor prognosis of affected patients, the lack of effective treatment options, with particular reference to biologic drugs, the absence of predictive markers for targeted treatment and the lack of knowledge about the basis of different biological and clinical behaviour of the two main histologic subtypes, epithelioid versus non-epithelioid (sarcomatoid/biphasic), constitute the rationale for the present study. AIMS: The first purpose of the study was to investigate new treatment options through preclinical evaluation of extrinsic apoptosis triggers (recombinant human Apo2L/TRAIL) in combination with intrinsic apoptosis inducers acting through the reactivation of p53, such as DNA-damaging agents (carboplatin/pemetrexed) or p53-MDM2 inhibitors (nutlin3-RG7112), both in vitro and in vivo. Moreover, the study aims to investigate new targets (MDM2, HIF1alpha, VEGF) for treatment in MPM tumor samples, testing possible different expression levels of such targets in the different histologic subtypes. Some morphological features, such as inflammation, necrosis and proliferation were quantified in the different histotypes and correlated with MDM2 and HIF1alpha. Finally, correlations between molecular data and clinical features were performed. METHODS: Anticancer effects of rhApo2L/TRAIL (Amgen, Genentech) plus chemotherapy (Carboplatin/Pemetrexed) or nutlin3-RG7112 (Roche) was evaluated in different cell lines through annexin V and caspases assay, and in a Severe Combined ImmunoDeficiency (SCID) mouse model. p53 expression levels were evaluated through western blot. TRAIL receptors were evaluated through flow cytometry. Formalin-Fixed Paraffin Embedded (FFPE) chemonaive tumor samples from MPM patients were analyzed: MDM2, VEGF and HIF1alpha mRNA and protein expression levels were investigated through RT-qPCR and immunohistochemistry (IHC) with specific antibodies, respectively. Proliferation was quantified through staining with Ki67 antibodies. Necrosis and inflammation were also quantified on histological sections using a grading score. Normal pleura samples from patients undergoing diagnostic surgery for non cancer disease were used as negative controls. Clinical data of the patients under study were collected in a password-protected database: age, gender, ECOG PS (Performance Status), EORTC score, stage, systemic treatments, surgery, radiotherapy, first progression and last follow-up date, status (alive/dead). RESULTS: In vitro and in vivo results showed a significant increase of apoptosis in cell lines and reduction of tumor volume in animal models treated with rhApo2L/TRAIL plus chemotherapy or nutlin3-RG7112 compared with those receiving single treatments. This synergistic effect was dependent on the ability of chemotherapy or nutlin3-RG7112 to increase the expression of the TRAIL receptors DR4 and DR5 in a p53 manner. Higher MDM2 and HIF1alpha IHC expression was significantly associated with sarcomatoid/biphasic histologic subtype (p=0.010 and p=0.007, respectively) with positive correlation between MDM2 and HIF1alpha expression levels (correlation coefficient=0.533; p value= 0.00626). Proliferation index was significantly higher in sarcomatoid/biphasic compared with epithelioid samples (p=0.005) and also significantly higher in tumor samples with higher MDM2 expression (p=0.008). Clinical and pathological features or biomarker did not show any correlation with prognosis, except for proliferation index and Progression Free Survival (PFS), even though the results of this exploratory analysis should be considered with caution because of the limited number of patients, the heterogeneous treatment received and the insufficient follow-up time in some patients. CONCLUSION: Our preclinical in vitro and in vivo results confirm that reactivation of p53 by chemotherapy or p53-MDM2 inhibitors effectively sensitizes to TRAIL-dependent apoptosis in malignant pleural mesothelioma. Our translational study in tumor samples from MPM patients confirmed different biological and pathological features and molecular targets expression in the two main histologic subtypes. It is tempting to speculate that MDM2 and Ki67 might be considered as further useful diagnostic tools to identify poor prognosis patients. Moreover, MDM2 and HIF1alpha might be considered as promising targets for anticancer treatment of MPM

An ex vivo model of the bovine mammary gland to study the pathogenesis of bacterial infections.

Mastitis represents the most important disease of dairy cattle. Stabilized or primary epithelial cell lines have been extensively used to study the molecular mechanisms of the immune response in the udder. Both models are considered reliable, but are constituted by a single cell population, i.e. epithelial cells, and changes in cell morphology and metabolism may occur, as a result of subculture, or even genetic instability. The aim of this study was to evaluate the immune response of an ex vivo model of the mammary gland, where the three-dimensional structure is maintained, assuming that the results were more comparable to the in vivo response. Ex vivo 2 mm3 -sections of a heifer udder were cultured under standardized conditions and treated for 3, 6, and 18 h with either E. coli lipopolysaccharide (LPS) or with S. aureus lipoteichoic acid (LTA). These molecules are constituent of the cell walls of Gram-negative or -positive bacteria, respectively and are applied as an inflammatory stimulus in the research of mastitis pathogenesis. Samples were analyzed for cell proliferation and apoptosis by immunofluorescence, in order to validate the model. Thereafter, we analyzed the mRNA expression of key molecules of the innate immune response (TNFα, IL-1β, IL-6, IL-8 and LAP) by quantitative real-time PCR. We used three reference genes validated by geNorm application, as the better internal standard for mammary gland tissue. The model did not show proliferation and apoptosis increased during the culture period. The preliminary results showed diverse patterns for the different cytokines and LAP: mRNA expression was overall increased, but peaked at different time points. These data suggest that such ex vivo model could be a valid approach to study the mammary immune response to bacteria

Real world data in the era of Immune Checkpoint Inhibitors (ICIs): Increasing evidence and future applications in lung cancer.

Immune checkpoint inhibitors (ICIs) targeting programmed death 1 (PD-1) and PD-ligand 1 (PD-L1) quickly subverted the standard of treatment in Non-Small Cell Lung Cancer (NSCLC), where they were first introduced in all comers previously treated advanced/metastatic NSCLC patients and subsequently in the first line of PD-L1 selected cases of metastatic and locally advanced disease. Treatment algorithm is an evolving landscape, where the introduction of front-line ICIs, with or without chemotherapy, unavoidably influences the following treatment lines. In this context, medical oncologists are currently facing many unclear issues, which have been not clarified so far by available data. Effectiveness and safety in special populations underrepresented in clinical trials - such as elderly, poor PS, hepatitis or human immunodeficiency virus-affected patients - are only a part of the unexplored side of ICIs in the real world. Indeed, pivotal randomized clinical trials (RCTs) often lack of external validity because eligibility criteria exclude some patient subgroups commonly treated in real-world clinical practice. Similarly, cost-effectiveness and sustainability of these innovative agents are important issues to be considered in the real-world. Though affected by several limitations, real-world evidence (RWE) studies allow to collect data regarding overall treated patients in clinical practice according to local authority regulations, overcoming the intrinsic limits of RCTs. The present review focuses on RWE about ICIs in lung cancer treatment, with particular reference to special patient populations, and discusses potential application of real-world data in a potential innovative drug development model

Impact of ABC transporters in osteosarcoma and ewing’s sarcoma: Which are involved in chemoresistance and which are not?

The ATP-binding cassette (ABC) transporter superfamily consists of several proteins with a wide repertoire of functions. Under physiological conditions, ABC transporters are involved in cellular trafficking of hormones, lipids, ions, xenobiotics, and several other molecules, including a broad spectrum of chemical substrates and chemotherapeutic drugs. In cancers, ABC transporters have been intensely studied over the past decades, mostly for their involvement in the multidrug resistance (MDR) phenotype. This review provides an overview of ABC transporters, both related and unrelated to MDR, which have been studied in osteosarcoma and Ewing’s sarcoma. Since different backbone drugs used in first-line or rescue chemotherapy for these two rare bone sarcomas are substrates of ABC transporters, this review particularly focused on studies that have provided findings that have been either translated to clinical practice or have indicated new candidate therapeutic targets; however, findings obtained from ABC transporters that were not directly involved in drug resistance were also discussed, in order to provide a more complete overview of the biological impacts of these molecules in osteosarcoma and Ewing’s sarcoma. Finally, therapeutic strategies and agents aimed to circumvent ABC-mediated chemoresistance were discussed to provide future perspectives about possible treatment improvements of these neoplasms

Polymorphic variants of IGF2BP3 and SENCR have an impact on predisposition and/or progression of Ewing sarcoma

Ewing sarcoma (EWS), the second most common malignant bone tumor in children and adolescents, occurs abruptly without clear evidence of tumor history or progression. Previous association studies have identified some inherited variants associated with the risk of developing EWS but a common picture of the germline susceptibility to this tumor remains largely unclear. Here, we examine the association between thirty single nucleotide polymorphisms (SNPs) of the IGF2BP3, a gene that codes for an oncofetal RNA-binding protein demonstrated to be important for EWS patient's risk stratification, and five SNPs of SENCR, a long non-coding RNA shown to regulate IGF2BP3. An association between polymorphisms and EWS susceptibility was observed for three IGF2BP3 SNPs - rs112316332, rs13242065, rs12700421 - and for four SENCR SNPs - rs10893909, rs11221437, rs12420823, rs4526784 -. In addition, IGF2BP3 rs34033684 and SENCR rs10893909 variants increased the risk for female respect to male subgroup when carried together, while IGF2BP3 rs13242065 or rs76983703 variants reduced the probability of a disease later onset (> 14 years). Moreover, the absence of IGF2BP3 rs10488282 variant and the presence of rs199653 or rs35875486 variant were significantly associated with a worse survival in EWS patients with localized disease at diagnosis. Overall, our data provide the first evidence linking genetic variants of IGF2BP3 and its modulator SENCR to the risk of EWS development and to disease progression, thus supporting the concept that heritable factors can influence susceptibility to EWS and may help to predict patient prognosis

Immune-related adverse events (irAEs) in advanced non-small cell lung cancer (aNSCLC): Platelet-to-lymphocyte ratio (PLR) predicts the risk of development and relapse

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Targeting GSTP1-1 induces JNK activation and leads to apoptosis in cisplatin-sensitive and -resistant human osteosarcoma cell lines

The effect of the glutathione transferase P1-1 (GSTP1-1) targeting has been investigated in both sensitive (U-2OS) and cisplatin-resistant (U-2OS/CDDP4μg) human osteosarcoma cell lines. Despite the different enzyme’s content, inhibition of GSTP1-1 by 6-(7-nitro-2,1,3-benzoxadiazol-4-ylthio)hexanol (NBDHEX) causes the activation of c-Jun N-terminal kinase (JNK) and apoptosis in both cell lines. However, different time courses of JNK activation and cell responses are observed. Whereas in the U-2OS/CDDP4μg cell line drug treatment results in an early increase of caspase activity and secondary necrosis, in the U-2OS cells it mainly causes cell cycle arrest followed by apoptosis. Thereafter, we detailed the action mechanism of NBDHEX in the U-2OS cell line. We report evidence of the interaction between GSTP1-1 and the TNF receptor associated factor 2 (TRAF2) and we demonstrate that NBDHEX is able to dissociate the GSTP1-1:TRAF2 complex. This restores the TRAF2:ASK1 signaling, thereby leading to the simultaneous and prolonged activation of JNK and p38. These mitogen-activated protein kinases (MAPKs) mediate different effects: JNK is crucial for apoptosis, whereas p38 causes an increase in the p21 level and a concomitant cell cycle arrest. Our study shows that GSTP1-1 plays an important regulatory role in TRAF signaling of osteosarcoma and discloses new features of the action mechanism of NBDHEX that suggest potentially practical consequences of these finding