SCD5 restored expression favors differentiation and epithelial-mesenchymal reversion in advanced melanoma

Our previous data supported a role for the Stearoyl-CoA desaturase (SCD5) in protection against malignancy, whereby it appears to functionally modify tumor stroma impairing tumor spread. SCD5 is significantly expressed in primary melanoma, but becomes barely detectable at tumor advanced stages. Looking for the regulatory mechanisms underlying SCD5 reduced expression during melanoma progression, we demonstrated a significantly lower stability of SCD5 protein as well as the direct targeting of SCD5 mRNA by the oncogenic miR-221 & 222 in metastatic cell lines. Moreover, our results indicated the existence of a negative feedback loop between SCD5 and miR-221 & 222, in good agreement with their opposite functions. Also, we showed how SCD5 re-expression and the direct supplementation of its main product oleic acid (OA) can drive advanced melanoma cell lines toward differentiation and reversion of the epithelial-mesenchymal (EMT)-like process, eventually inducing a less malignant phenotype. Indeed, SCD5 re-established the sensitivity to all-trans retinoic acid in A375M metastatic melanoma, associated with increased levels of Tyrosinase, melanin production and reduced proliferation. As evidenced by the correct modulation of some key transcription factors, SCD5 managed by favoring a partial mesenchymal-to-epithelial (MET) transition in in vitro studies. Interestingly, a more complete MET, including E-cadherin re-expression correctly localized at cell membranes, was obtained in in vivo xenograft models, thus indicating the requirement of direct contacts between tumor cells and the surrounding microenvironment as well as the presence of some essential factors for SCD5 complete function

Exosome-mediated transfer of miR-222 is sufficient to increase tumor malignancy in melanoma

BACKGROUND: Growing evidence is showing that metastatic cell populations are able to transfer their characteristics to less malignant cells. Exosomes (EXOs) are membrane vesicles of endocytic origin able to convey their cargo of mRNAs, microRNAs (miRs), proteins and lipids from donors to proximal as well as distant acceptor cells. Our previous results indicated that miR-221&222 are key factors for melanoma development and dissemination. The aim of this study was to verify whether the tumorigenic properties associated with miR-222 overexpression can be also propagated by miR-222-containing EXOs. METHODS: EXOs were isolated by UltraCentrifugation or Exoquick-TC(®) methods. Preparations of melanoma-derived vesicles were characterized by using the Nanosight™ technology and the expression of exosome markers analyzed by western blot. The expression levels of endogenous and exosomal miRNAs were examined by real time PCR. Confocal microscopy was used to evaluate transfer and uptake of microvesicles from donor to recipient cells. The functional significance of exosomal miR-222 was estimated by analyzing the vessel-like process formation, as well as cell cycle rates, invasive and chemotactic capabilities. RESULTS: Besides microvesicle marker characterization, we evidenced that miR-222 exosomal expression mostly reflected its abundance in the cells of origin, correctly paralleled by repression of its target genes, such as p27Kip1, and induction of the PI3K/AKT pathway, thus confirming its functional implication in cancer. The possible differential significance of PI3K/AKT blockade was assessed by using the BKM120 inhibitor in miR-222-transduced cell lines. In addition, in vitro cultures showed that vesicles released by miR-222-overexpressing cells were able to transfer miR-222-dependent malignancy when taken-up by recipient primary melanomas. Results were confirmed by antagomiR-221&222 treatments and by functional observations after internalization of EXOs devoid of these miRs

HOXB1 restored expression promotes apoptosis and differentiation in the HL60 leukemic cell line

BACKGROUND: Homeobox (HOX) genes deregulation has been largely implicated in the development of human leukemia. Among the HOXB cluster, HOXB1 was silent in a number of analyzed acute myeloid leukemia (AML) primary cells and cell lines, whereas it was expressed in normal terminally differentiated peripheral blood cells. METHODS: We evaluated the biological effects and the transcriptome changes determined by the retroviral transduction of HOXB1 in the human promyelocytic cell line HL60. RESULTS: Our results suggest that the enforced expression of HOXB1 reduces cell growth proliferation, inducing apoptosis and cell differentiation along the monocytic and granulocytic lineages. Accordingly, gene expression analysis showed the HOXB1-dependent down-regulation of some tumor promoting genes, paralleled by the up-regulation of apoptosis- and differentiation-related genes, thus supporting a tumor suppressor role for HOXB1 in AML. Finally, we indicated HOXB1 promoter hypermethylation as a mechanism responsible for HOXB1 silencing. CONCLUSIONS: We propose HOXB1 as an additional member of the HOX family with tumour suppressor properties suggesting a HOXB1/ATRA combination as a possible future therapeutic strategy in AML

Effect of miR-204&211 and RUNX2 control on the fate of human mesenchymal stromal cells

MiR-204 and 211 enforced expression in murine mesenchymal stromal cells (MSCs) has been shown to induce adipogenesis and impair osteogenesis, through RUNX2 down-modulation. This mechanism has been suggested to play a role in osteoporosis associated with obesity. However, two further fundamental MSC functions, chondrogenesis and hematopoietic supporting activity, have not yet been explored. To this end, we transduced, by a lenti-viral vector, miR-204 and 211 in a model primary human MSC line, opportunely chosen among our MSC collection for displaying all properties of canonical bone marrow MSCs, except adipogenesis. Enforced expression of miR-204&211 in these cells, rescued adipogenesis, and inhibited osteogenesis, as previously reported in murine MSCs, but, surprisingly, also damaged cartilage formation and hematopoietic supporting activity, which were never explored before. RUNX2 has been previously indicated as the target of miR-204&211, whose down modulation is responsible for the switch from osteogenesis to adipogenesis. However, the additional disruption of chondrogenesis and hematopoietic supporting activity, which we report here, might depend on diverse miR-204&211 targets. To investigate this hypothesis, permanent RUNX2 knock-down was performed. Sh-RUNX2 fully reproduced the phenotypes induced by miR-204&211, confirming that RUNX2 down modulation is the major event leading to the reported functional modification on our MSCs. It seems thus apparent that RUNX2, a recognized master gene for osteogenesis, might rule all four MSC commitment and differentiation processes. Hence, the formerly reported role of miR204&211 and RUNX2 in osteoporosis and obesity, coupled with our novel observation showing inhibition of cartilage differentiation and hematopoietic support, strikingly resemble the clinical traits of metabolic syndrome, where osteoarthritis, osteoporosis, anaemia and obesity occur together. Our observations, corroborating and extending previous observations, suggest that miR-204&211-RUNX2 axis in human MSCs is possibly involved in the pathogenesis of this rapidly growing disease in industrialized countries, for possible therapeutic intervention to regenerate former homeostasis

Acidic microenvironment plays a key role in human melanoma progression through a sustained exosome mediated transfer of clinically relevant metastatic molecules

Background: Microenvironment cues involved in melanoma progression are largely unknown. Melanoma is highly influenced in its aggressive phenotype by the changes it determinates in its microenvironment, such as pH decrease, in turn influencing cancer cell invasiveness, progression and tissue remodelling through an abundant secretion of exosomes, dictating cancer strategy to the whole host. A role of exosomes in driving melanoma progression under microenvironmental acidity was never described. Methods: We studied four differently staged human melanoma lines, reflecting melanoma progression, under microenvironmental acidic pHs pressure ranging between pH 6.0-6.7. To estimate exosome secretion as a function of tumor stage and environmental pH, we applied a technique to generate native fluorescent exosomes characterized by vesicles integrity, size, density, markers expression, and quantifiable by direct FACS analysis. Functional roles of exosomes were tested in migration and invasion tests. Then we performed a comparative proteomic analysis of acid versus control exosomes to elucidate a specific signature involved in melanoma progression. Results: We found that metastatic melanoma secretes a higher exosome amount than primary melanoma, and that acidic pH increases exosome secretion when melanoma is in an intermediate stage, i.e. metastatic non-invasive. We were thus able to show that acidic pH influences the intercellular cross-talk mediated by exosomes. In fact when exposed to exosomes produced in an acidic medium, pH naïve melanoma cells acquire migratory and invasive capacities likely due to transfer of metastatic exosomal proteins, favoring cell motility and angiogenesis. A Prognoscan-based meta-analysis study of proteins enriched in acidic exosomes, identified 11 genes (HRAS, GANAB, CFL2, HSP90B1, HSP90AB1, GSN, HSPA1L, NRAS, HSPA5, TIMP3, HYOU1), significantly correlating with poor prognosis, whose high expression was in part confirmed in bioptic samples of lymph node metastases. Conclusions: A crucial step of melanoma progression does occur at melanoma intermediate -stage, when extracellular acidic pH induces an abundant release and intra-tumoral uptake of exosomes. Such exosomes are endowed with pro-invasive molecules of clinical relevance, which may provide a signature of melanoma advancement

Hemoglobin and Neutrophil Count as Prognostic Factors in Cholangiocarcinoma Patients in 2nd Line Treatment Setting: Results from a Small Monocentric Retrospective Study

Background: Unresectable cholangiocarcinoma prognosis can be extremely variable due to different symptoms and sites of disease involvement at diagnosis and unpredictable chemotherapy response rates. Most patients will usually receive 1st line palliative chemotherapy with platinum compounds and Gemcitabine or Gemcitabine alone. Only a few patients maintain adequate performance status after first-line treatment failure: second-line treatment with FOLFOX or FOLFIRI chemotherapy has been used in this setting with modest overall survival improvement. There is a lack of data concerning whether laboratory findings might help clinicians in identifying those patients with the highest likelihood of benefiting from 2nd line treatment. The aim of this analysis is to assess the prognostic role of a series of easily available laboratory tests in patients with bile duct cancer who received 2nd line chemotherapy. Patients and Methods: Patients with unresectable bile duct cancer treated in 2nd-line setting with platinum-based chemotherapy doublet or FOLFIRI were enrolled. The primary objective of the analysis was to assess overall survival (OS) differences among patients based on the results of lab tests. Serum hemoglobin, neutrophil, lymphocyte, monocyte, platelet absolute count, creatinine, total bilirubin, albumin, LDH, circulating CEA and CA19.9 values were collected at the start of 2nd line treatment. Cut-off values for all lab tests were set by ROC curve analysis. Survival was calculated by the Kaplan–Meier method and differences in survival among stratification factors were assessed by Log-rank test. Cox-proportional-hazard regression was used for multivariate analysis. Level of statistical significance p was set at 0.05 for all tests. Correction for false discovery error rate was performed by Holm’s stepdown procedure. Results: A total of 46 patients were eligible. Median overall survival of the entire cohort was 8.98 months (95%CI: 6.68–13.93) while mean OS was 17.10 months (standard error: 3.16). Using 6.2 months OS landmark as classification variable for ROC curve analysis, only serum hemoglobin (cut-off: >10 g/dL), albumin (cut-off: >3.5 mg/dL), CA19.9 (cut-off: ≤668 UI/mL), monocyte (cut-off: ≤510/mmc) and neutrophil count (cut-off: ≤5140/mmc) were significantly associated with the chosen end-point. Multivariate analysis confirmed an independent statistically significant impact on overall survival only for hemoglobin (Exp(b): 0.12, p = 0.0023) and neutrophil count (Exp(b): 0.30, p = 0.0039). Based on these results, using both hemoglobin and neutrophil count, three prognostic groups were defined: patients with both favorable factors had 12.63 months median OS vs. 6.75 months of patients with only one favorable factor vs. 1.31 months of those with neither. The difference between these three groups of patients was statistically significant (p < 0.0001). Discussion: Second-line palliative chemotherapy can be a potentially useful option for a few patients with unresectable/metastatic bile duct cancer. Even though assessment of patients’ prognosis might be difficult due to the complex behavior of this disease, a series of easily available laboratory tests might be used for these means: serum hemoglobin and neutrophil count we0re able to define subsets of patients with entirely different prognoses. It is hoped that this score will be prospectively validated in a larger group of patients in order to improve treatment decisions in patients with unresectable bile duct cancer candidate to receive palliative 2nd line chemotherapy