Chloroquine Triggers Cell Death and Inhibits PARPs in Cell Models of Aggressive Hepatoblastoma

Background:Hepatoblastoma (HB) is the most common pediatric liver malignancy. Despite advances in chemotherapeutic regimens and surgical techniques, the survival of patients with advanced HB remains poor, underscoring the need for new therapeutic approaches. Chloroquine (CQ), a drug used to treat malaria and rheumatologic diseases, has been shown to inhibit the growth and survival of various cancer types. We examined the antineoplastic activity of CQ in cell models of aggressive HB. Methods:Seven human HB cell models, all derived from chemoresistant tumors, were cultured as spheroids in the presence of relevant concentrations of CQ. Morphology, viability, and induction of apoptosis were assessed after 48 and 96 h of CQ treatment. Metabolomic analysis and RT-qPCR based Death Pathway Finder array were used to elucidate the molecular mechanisms underlying the CQ effect in a 2-dimensional cell culture format. Quantitative western blotting was performed to validate findings at the protein level. Results:CQ had a significant dose and time dependent effect on HB cell viability both in spheroids and in 2-dimensional cell cultures. Following CQ treatment HB spheroids exhibited increased caspase 3/7 activity indicating the induction of apoptotic cell death. Metabolomic profiling demonstrated significant decreases in the concentrations of NAD(+)and aspartate in CQ treated cells. In further investigations, oxidation of NAD(+)decreased as consequence of CQ treatment and NAD(+)/NADH balance shifted toward NADH. Aspartate supplementation rescued cells from CQ induced cell death. Additionally, downregulated expression of PARP1 and PARP2 was observed. Conclusions:CQ treatment inhibits cell survival in cell models of aggressive HB, presumably by perturbing NAD(+)levels, impairing aspartate bioavailability, and inhibiting PARP expression. CQ thus holds potential as a new agent in the management of HB.Peer reviewe

Evolution de l'activite cytotoxique antitumorale spontanee des lymphocytes NK chez des Rats soumis a la cancerogenese par le nickel : role de l'interferon

SIGLECNRS T 56738 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Molecular characterization of Kaposi’s sarcoma-associated herpesvirus/human herpesvirus-8 strains from Russia

International audienceWe report the molecular characterization, with subtyping of both K1 and K14.1/K15 genomic regions, of seven new human herpesvirus-8 (HHV-8) strains from Russian patients with classical Kaposi's sarcoma. Phylogenetic studies, based on the complete K1 gene/protein analysis, indicate that six of these strains belong to the A subtype, with one belonging to the A4 group and exhibiting a unique deletion of 19 amino acids in the VR2 region at position 186-204. PCR-based studies of the K14.1/K15 genomic region indicate that four of the new strains were of the M subtype while three belonged to the P subtype. Our study indicates an important genetic diversity of the HHV-8 strains currently present in Russia, including a new peculiar strain possessing a unique deletion in the VR2 segment, and confirms the absence of correlation between the K1 and K14.1/K15 molecular subtypes, as M and P genotypes can be observed in the A K1 subtype

Vav1 Selectively Down-Regulates Akt2 through miR-29b in Certain Breast Tumors with Triple Negative Phenotype

Triple negative breast cancer (TNBC) represents the most aggressive breast tumor, showing a high intrinsic variability in terms of both histopathological features and response to therapies. Blocking the Akt signaling pathway is a well-studied approach in the treatment of aggressive breast tumors. The high homology among the Akt isoforms and their distinct, and possibly opposite, oncogenic functions made it difficult to develop effective drugs. Here we investigated the role of Vav1 as a potential down-regulator of individual Akt isozymes. We revealed that the over-expression of Vav1 in triple negative MDA-MB-231 cells reduced only the Akt2 isoform, acting at the post-transcriptional level through the up-modulation of miR-29b. The Vav1/miR-29b dependent decrease in Akt2 was correlated with a reduced lung colonization of circulating MDA-MB-231 cells. In cell lines established from PDX, the Vav1 induced down-modulation of Akt2 is strongly dependent on miR-29b and occurs only in some TNBC tumors. These findings may contribute to better classify breast tumors having the triple negative phenotype, and suggest that the activation of the Vav1/miR-29b axis, precisely regulating the amount of an Akt isozyme crucial for tumor dissemination, could have great potential for driving more accurate therapies to TNBCs, often not eligible or resistant to treatments

SSEA4 AND ST3GAL2 AS CHEMOTHERAPEUTIC DRUG RESPONSE BIOMARKERS

In the field of oncology, biomarkers are used to calculate the prognosis of a malignancy, predict suitable treatments, monitor disease progression, and evaluate treatment impact. The range of used biomarkers is extremely wide. Morphological or histological characteristics but also molecular markers on the protein and RNA and DNA level are frequently used. Whereas good markers for the majority of targeted therapies exist, for most tumor entities there is a lack of markers that can be used to predict the response for systemic therapies like chemotherapy. In breast cancer, chemotherapy is predominately used for stage 2–4 disease, being particularly beneficial in estrogen receptor-negative (ER-) disease. Usually, several drugs are given in combinations, and one of the most common treatments is cyclophosphamide plus doxorubicin (Adriamycin®), known as A/C. In general, chemotherapy works by unspecifically destroying fast-growing/fast-replicating cells. In the case of A/C cell death is induced by causing DNA damage during replication. Due to the general mechanism of action for the majority of chemotherapy agents, these drugs next to targeting tumor cells also damage fast-growing normal cells where they cause serious side effects like hair loss or liver and gastrointestinal complications. Although less than 25% of breast cancer patients benefit from chemotherapeutic treatment, this systemic approach is still used as standard care. Because of the severe side effects, it would be highly beneficial to identify markers which can be used to predict the response to chemotherapy preventing treatment of de-novo resistant tumors. In the present invention, we identify SSEA4 (stage-specific embryonic antigen-4), a sialyl-glycolipid, and ST3GAL2, the synthesizing enzyme of SSEA4, as diagnostic and drug response biomarkers in cancer. Expression of SSEA4 and/or ST3GAL2 on/in cancerous cells predicts the outcome for chemotherapeutic treatment of these cells. SSEA4 and/or ST3GAL2 can be used as biomarkers in a method to predict resistance to chemotherapy in an individual with cancer

Targeting the Vav1/miR‐29b axis as a potential approach for treating selected molecular subtypes of triple‐negative breast cancer

MicroRNA (miR)‑29b has been reported to play a controversial role in breast cancer, particularly triple‑negative breast cancer (TNBC). Based on our previous data revealing that the PU.1‑mediated expression of miR‑29b in cells from acute myeloid leukemia is sustained by Vav1, the potential role of this multidomain protein in modulating miR‑29b levels in breast tumor cells, in which Vav1 is ecstopically expressed and shows a nuclear accumulation, was investigated. Breast cancer cell lines with various phenotypes and patient‑derived xenograft‑derived TNBC cells were subjected to Vav1 modulation and reverse transcription quantitative PCR of miR‑29b levels. The recruitment of CCAAT enhancer binding protein α (CEBPα) to miR‑29b promoters was investigated by quantitative chromatin immunoprecipitation assays. It was found that Vav1 was essential for the recovery of mature miR‑29b in breast cancer cell lines, and that it promoted the expression of the miRNA in TNBC cells of the mesenchymal molecular subtype by sustaining the transcription of the miR‑29b1/a cluster mediated by CEBPα. The present results suggest that Vav1 is a crucial modulator of miR‑29b expression in breast tumor cells, and this finding may help identify strategies that may be useful in the management of TNBC by targeting the Vav1/miR‑29b axis, as there is a lack of molecular‑based treatments for TNBC.MicroRNA (miR)-29b has been reported to play a controversial role in breast cancer, particularly triple-negative breast cancer (TNBC). Based on our previous data revealing that the PU.1-mediated expression of miR-29b in cells from acute myeloid leukemia is sustained by Vav1, the potential role of this multidomain protein in modulating miR-29b levels in breast tumor cells, in which Vav1 is ecstopically expressed and shows a nuclear accumulation, was investigated. Breast cancer cell lines with various phenotypes and patient-derived xenograft-derived TNBC cells were subjected to Vav1 modu- lation and reverse transcription quantitative PCR of miR-29b levels. The recruitment of CCAAT enhancer binding protein α (CEBPα) to miR-29b promoters was investigated by quantita- tive chromatin immunoprecipitation assays. It was found that Vav1 was essential for the recovery of mature miR-29b in breast cancer cell lines, and that it promoted the expression of the miRNA in TNBC cells of the mesenchymal molecular subtype by sustaining the transcription of the miR-29b1/a cluster mediated by CEBPα. The present results suggest that Vav1 is a crucial modulator of miR-29b expression in breast tumor cells, and this finding may help identify strategies that may be useful in the management of TNBC by targeting the Vav1/miR-29b axis, as there is a lack of molecular-based treat- ments for TNBC

Virological and Molecular Characterisation of a New B Lymphoid Cell Line, Established from an AIDS Patient with Primary Effusion Lymphoma, Harbouring Both KSHV/HHV8 and EBV Viruses

International audienceWe report here a new case of primary effusion lymphoma (PEL), occurring in a French homosexual HIV-1 infected male with a pericardial, pleural and mesenteric tumour dissemination, and the establishment from his pleural effusion of a new cell line, Cra-BCBL, dually infected by EBV and KSHV/HHV8. Cra-BCBL cells are of B-cell origin as judged by their clonal immunoglobulin heavy chain (IgH) gene rearrangement, identical to that of the parental tumour. Both the cell line and the lymphoma cells expressed CD38 and CD45 antigens but no classical B-cell or T-cell lineage-restricted antigens. Cra-BCBL harbours a type I EBV virus, expressing a latency type II. Expression of KSHV/HHV8 ORF72 and ORF75 was detected by RT/PCR. In addition, KSHV lytic replication could be induced by treatment by n-butyrate. An equivalent and high copy number of KSHV genomes (20 to 200 copies by cell) was detected both in the primary tumour cells and in the cell line. Southern blot (SB) analysis of EBV terminal repeats (TR) displayed the same unique band in the cell line DNA and in the original tumour cells, consistent with a monoclonal infection of EBV. Furthermore, SB analysis of KSHV/HHV8 TR revealed the same hybridisation pattern between Cra-BCBL and the effusion cells, with a common band at around 30-40 kb corresponding to the fused termini of the viral episomes and a 5 Kb rearranged fragment. The new cell line characterised here could be a useful model to study interactions between two human herpes viruses and their contribution to lymphomagenesis