Expression of Bcl2L12 in chronic lymphocytic leukemia patients: association with clinical and molecular prognostic markers

Dynamic changes in autophagy activity in different degrees of pulmonary fibrosis in mice

The aim of this study is to observe the changes in autophagy activities in lung tissues of mice with different degrees of pulmonary fibrosis (PF), and explore the association between PF and autophagy activity. The PF model was established by bleomycin (BLM, 25 and 35 mg/kg) atomization inhalation in C57BL/6 mice, samples were collected on the 7, 14, and 28 days after BLM administration. Hematoxylin-eosin staining was used to observe the pathological changes in lung tissues. Masson staining was utilized to assess areas of blue collagen fiber deposition in lung tissues. Quantitative real time polymerase chain reaction was used to detect the mRNA expressions of autophagy-related genes, including Atg5, Atg7, and Atg10 in lung tissues. Western blot was used to detect the protein expressions of autophagy-related genes, including p62 and LC3II/LC3I in lung tissues. Compared with control group, BLM dose-dependently decreased PaO2, mRNA expressions of Atg5, Atg7, Atg10, and LC3II/LC3I, while increased lung wet weight, lung coefficient, PF score, the blue area of collagen fibers, and p62 protein on the 7th, 14th, and 28th days. In conclusion, the more severe the PF induced by BLM, the lower the autophagy activity.

Nifuroxazide induces the apoptosis of human non‑small cell lung cancer cells through the endoplasmic reticulum stress PERK signaling pathway

The aim of the present study was to investigate the molecular mechanism of nifuroxazide (NFZ) in the induction of apoptosis of NCI-H1299 human non-small cell lung cancer (NSCLC) cells through the reactive oxygen species (ROS)/Ca²⁺/protein kinase R-like ER kinase (PERK)-activating transcription factor 4 (ATF4)-DNA damage inducible transcript 3 (CHOP) signaling pathway. Morphological changes of cells were observed by microscopy, and the apoptosis and intracellular ROS levels of cells were observed by inverted fluorescence microscopy. Cell viability after the addition of the PERK inhibitor, GSK2606414, were detected by Cell Counting Kit-8 assay. Annexin V-FITC was used to detect cell apoptosis, Brite 670 was used to detect intracellular ROS and Fura Red AM was used to detect Ca²⁺ content. Western blotting was used to detect PERK, phosphorylated (P)-PERK, ATF4, CHOP, P-Janus kinase 2 and P-signal transducer and activator of transcription 3 expression levels. Compared with the dimethyl sulfoxide control group, NFZ inhibited the survival activity in the H1299 NSCLC cell line, in a time- and dose-dependent manner. However, GSK2606414 inhibited the NFZ-induced apoptosis of H1299 cells. GSK2606414 also inhibited the increase in ROS and Ca²⁺ in H1299 cells induced by NFZ. Western blotting results demonstrated that NFZ significantly increased the expression levels of P-PERK, ATF4 and CHOP, whereas GSK2606414 significantly reduced the NFZ-induced increase in these protein expression levels. In conclusion, NFZ may induce the apoptosis of H1299 NSCLC cells through the ROS/Ca²⁺/PERK-ATF4-CHOP signaling pathway.

Targeting CXCR4 to suppress glioma-initiating cells and chemoresistance in glioma

Glioma initiating cells (GICs), also known as glioma stem cells, display the capacity to recapitulate the functional diversity within the tumor. Despite the great progress achieved over the last decades, defining the key molecular regulators of GICs has represented a major obstacle in this field. In our study, data from The Cancer Genome Atlas database illustrated a relationship between C-X-C motif chemokine receptor 4 (CXCR4) expression and the survival of glioma patients. Mechanistically, we further indicated that CXCR4 mediated the upregulation of Kruppel like factor 5 (KLF5), a zinc-finger-containing transcription factor, to facilitate the proliferation of GICs. What's more, CXCR4 also enhanced the chemoresistance through KLF5/Bcl2-like 12 (BCl2L12) in glioma. The elevated expression of KLF5 and BCL2L12 induced by CXCR4 was dependent on phosphoinositide 3-kinases (PI3K)/serine/threonine kinase (AKT) signaling. Importantly, combined application of temozolomide and a CXCR4 inhibitor efficiently reversed CXCR4 mediated drugs resistance and improved anticancer effects in vivo. Collectively, our findings confirmed that CXCR4 promoted GICs proliferation via the KLF5/BCL2L12 dependent pathway, which may enrich the understanding of GICs and help drive the design of efficacious therapeutic strategies.

Evaluating the mechanism underlying antitumor effect of interleukin 27 on B cells of chronic lymphocytic leukemia patients

Chronic lymphocyte leukemia (CLL) is a B-cell malignancy resisted to apoptosis. Recently, some studies indicated that cytokines such as interleukin 27 (IL-27) can reduce B-cell proliferation. The aim of this study is to evaluate the mechanism underlying the proapoptotic effect of IL-27 on B cells of patients with CLL in comparison with B cells of normal subjects. The effect of IL-27 on the antitumor activity of natural killer (NK) and T cells was also evaluated. Peripheral blood mononuclear cells (PBMCs) were isolated from 35 patients with CLL and 15 normal subjects. B cells and PBMCs were cocultured with IL-27 and B cells apoptosis to evaluate proliferation. Both messenger RNA and protein expression of IL-27 and IL-27 receptor were determined using flow cytometry and real-time polymerase chain reaction analysis. To evaluate the apoptotic effect of IL-27 on B cells of patients with CLL, Annexin V-FITC and 7-AAD (BioLegend) fluorescent dyes were used. In addition, the IL-27 effect on activation of T cell and NK cell was determined by determining CD96 molecule expression. IL-27 and IL-27 receptor expression in patients with CLL was significantly lower than that of normal subjects (p < .05). IL-27 enhanced apoptosis of B cells in patients with CLL (p < .05) but this effect was not significantly observed in B cells of normal subjects (p > .05). Consequently, IL-27 reduced the proliferation of B cells and enhanced NK cell activity (p < .05). IL-27, through inducing apoptosis, can exert an inhibitory effect on cancer B cells of CLL patients with minimal effect on normal B cells.

Functional Change of Effector Tumor-Infiltrating CCR5+CD38+HLA-DR+CD8+ T Cells in Glioma Microenvironment

Human glioma facilitates an impaired anti-tumor immunity response, including defects in circulation of T lymphocytes. The level of CD8⁺ T-cell activation acts as an immune regulator associated with disease progression. However, little is known about the characteristics of peripheral and tumor-infiltrating CD8⁺ T cells in patients with glioma. In this study, we examined the level of CD8⁺ T-cell activation in a group of 143 patients with glioma and determined that peripheral CD3⁺ T cells decreased in accordance with disease severity. The patients' peripheral CD8⁺ T-cell populations were similar to that of healthy donors, and a small amount of CD8⁺ tumor-infiltrating lymphocytes was identified in glioma tissues. An increase in activated CD8⁺ T cells, characterized as CD38⁺HLA-DR⁺, and their association with disease progression were identified in the patients' peripheral blood and glioma, and shown to display enriched CCR5⁺ and TNFR2⁺ expression levels. Ex vivo examination of CD38⁺HLA-DR⁺CD8⁺ T cells indicated that this subset of cells displayed stronger secretion of IFN-γ and IL-2 before and after a 6-h stimulation with phorbol 12-myristate 13-acetate (PMA) and ionomycin (ION) relative to healthy CD38⁺HLA-DR⁺CD8⁺ T cells, indicating the functional feasibility of CD38⁺HLA-DR⁺CD8⁺ T cells. Higher CCL5 protein and mRNA levels were identified in glioma tissues, which was consistent with the immunohistochemistry results revealing both CCL5 and CD38⁺HLA-DR⁺CD8⁺ T cell expression. Patients' CCR5⁺CD38⁺HLA-DR⁺CD8⁺ T cells were further validated and shown to display increases in CD45RA⁺CCR7^- and T-bet⁺ accompanied by substantial CD107-a, IFN-γ, and Granzyme B levels in response to glioma cells.

BCL2L12 improves risk stratification and prediction of BFM-chemotherapy response in childhood acute lymphoblastic leukemia

Background Risk-adjusted treatment has led to outstanding improvements of the remission and survival rates of childhood acute lymphoblastic leukemia (ALL). Nevertheless, overtreatment-related toxicity and resistance to therapy have not been fully prevented. In the present study, we evaluated for the first time the clinical impact of the apoptosis-related BCL2L12 gene in prognosis and risk stratification of BFM-treated childhood ALL. Methods Bone marrow specimens were obtained from childhood ALL patients upon disease diagnosis and the end-of-induction (EoI; day 33) of the BFM protocol, as well as from control children. Following total RNA extraction and reverse transcription, BCL2L12 expression levels were determined by qPCR. Patients' cytogenetics, immunophenotyping and minimal residual disease (MRD) evaluation were performed according to the international guidelines. Results BCL2L12 expression was significantly increased in childhood ALL and correlated with higher BCL2/BAX expression ratio and favorable disease markers. More importantly, BCL2L12 expression was associated with disease remission, while the reduced BCL2L12 expression was able to predict patients' poor response to BFM therapy, in terms of M2-M3 response and MRD≥0.1% on day 15. The survival analysis confirmed the significantly higher risk of the BFM-treated patients underexpressing BCL2L12 at disease diagnosis for early relapse and worse survival. Lastly, evaluation of BCL2L12 expression clearly strengthened the prognostic value of the established disease prognostic markers, leading to superior prediction of patients' outcome and improved specificity of BFM risk stratification. Conclusions The expression levels of the apoptosis-related BCL2L12 predict response to treatment and survival outcome of childhood ALL patients receiving BFM chemotherapy.

Multiple myeloma-derived Jagged ligands increases autocrine and paracrine interleukin-6 expression in bone marrow niche

Multiple myeloma cell growth relies on intrinsic aggressiveness, due to a high karyotypic instability, or on the support from bone marrow (BM) niche.

We and other groups have provided evidences that Notch signaling is related to tumor cell growth, pharmacological resistance, localization/recirculation in the BM and bone disease.

This study indicates that high gene expression levels of Notch signaling members (JAG1, NOTCH2, HES5 and HES6) correlate with malignant progression or high-risk disease, and Notch signaling may participate in myeloma progression by increasing the BM levels of interleukin-6 (IL-6), a major player in myeloma cell growth and survival. Indeed, in vitro results, confirmed by correlation analysis on gene expression profiles of myeloma patients and immunohistochemical studies, demonstrated that Notch signaling controls IL-6 gene expression in those myeloma cells capable of IL-6 autonomous production as well as in surrounding BM stromal cells. In both cases Notch signaling activation may be triggered by myeloma cell-derived Jagged ligands. The evidence that Notch signaling positively controls IL-6 in the myeloma-associated BM makes this pathway a key mediator of tumor-directed reprogramming of the bone niche.

This work strengthens the rationale for a novel Notch-directed therapy in multiple myeloma based on the inhibition of Jagged ligands.

Association of Bax Expression and Bcl2/Bax Ratio with Clinical and Molecular Prognostic Markers in Chronic Lymphocytic Leukemia

Background

In chronic lymphocytic leukemia (CLL), in vivo apoptotic resistance of malignant B lymphocytes results, in part, from the intrinsic defects of their apoptotic machinery. These include genetic alterations and aberrant expression of many apoptosis regulators, among which the Bcl2 family members play a central role.

Aim

The aim of this study was to investigate the association of pro-apoptotic Bax gene expression and Bcl2/Bax ratio with the clinical features of CLL patients as well as with molecular prognostic markers, namely the mutational status of rearranged immunoglobulin heavy variable (IGHV) genes and lipoprotein lipase (LPL) gene expression.

Methods

We analyzed the expression of Bax mRNA and Bcl2/Bax mRNA ratio in the peripheral blood mononuclear cells of 58 unselected CLL patients and 10 healthy controls by the quantitative reverse-transcriptase polymerase chain reaction.

Results

We detected significant Bax gene overexpression in CLL samples compared to non-leukemic samples (p=0.003), as well as an elevated Bcl2/Bax ratio (p=<0.001). Regarding the association with prognostic markers, the Bcl2/Bax ratio showed a negative correlation to lymphocyte doubling time (r=-0.307; p=0.0451), while high-level Bax expression was associated with LPL-positive status (p=0.035). Both the expression of Bax and Bcl2/Bax ratio were higher in patients with unmutated vs. mutated IGHV rearrangements, but this difference did not reach statistical significance.

Conclusions

Our results suggest that dysregulated expression of Bcl2 and Bax, which leads to a high Bcl2/Bax ratio in leukemic cells, contributes to the pathogenesis and clinical course of CLL.

Identification of novel alternative splice variants of the BCL2L12 gene in human cancer cells using next-generation sequencing methodology

The next-generation sequencing (NGS) technology has enabled genome-wide studies, providing massively parallel DNA sequencing. NGS applications constitute a revolution in molecular biology and genetics and have already paved new ways in cancer research. BCL2L12 is an apoptosis-related gene, previously cloned from members of our research group. Like most members of the BCL2 gene family, it is highly implicated in various types of cancer and hematological malignancies. In the present study, we used NGS to discover novel alternatively spliced variants of the apoptosis-related BCL2L12 gene in many human cancer cell lines, after 3'-RACE nested PCR. Extensive computational analysis uncovered new alternative splicing events and patterns, resulting in novel alternative transcripts of the BCL2L12 gene. PCR was then performed to validate NGS data and identify the derived novel transcripts of the BCL2L12 gene. Therefore, 50 novel BCL2L12 splice variants were discovered. Since BCL2L12 is involved in the apoptotic machinery, the quantification of distinct BCL2L12 transcripts in human samples may have clinical applications in different types of cancer.

The novel function of CD82 and its impact on BCL2L12 via AKT/STAT5 signal pathway in acute myelogenous leukemia cells

The aim of this study was to explore the biological functions of a tetraspanin family protein CD82 expressed aberrantly in chemotherapy-resistant CD34(+)/CD38(-) acute myelogenous leukemia (AML) cells. Microarray analysis of patient-isolated CD34(+)/CD38(-) AML cells revealed that the levels of anti-apoptotic protein BCL2L12 were downregulated after CD82 depletion by specific short hairpin RNA (shRNA). Western blot analysis indicated that BCL2L12 was aberrantly expressed in patient-isolated AML cells and AML cell lines. Furthermore, CD82 blockade by a specific antibody downregulated BCL2L12 in parallel with dephosphorylation of signal transducer and activator of transcription 5 (STAT5) and AKT, whereas pharmacological inhibition of STAT5 and AKT activation decreased BCL2L12 expression in leukemia cells. In addition, shRNA-mediated downregulation of BCL2L12 increased the levels of cleaved caspase-3 and suppressed proliferation of leukemia cells, impairing their engraftment in immunodeficient mice. Taken together, our results indicate that CD82 regulated BCL2L12 expression via STAT5A and AKT signaling and stimulated proliferation and engrafting of leukemia cells, suggesting that CD82 and BCL2L12 may be promising therapeutic targets in AML.

High p27 protein levels in chronic lymphocytic leukemia are associated to low Myc and Skp2 expression, confer resistance to apoptosis and antagonize Myc effects on cell cycle

Myc (c-Myc) counteracts p27 effects, and low p27 usually correlates with high Myc expression in human cancer. However there is no information on the co-expression of both genes in chronic lymphocytic leukemia (CLL). We found a lack of correlation between RNA and protein levels of p27 and Myc in CLL cells, so we determined the protein levels by immunoblot in 107 cases of CLL. We observed a high p27 protein expression in CLL compared to normal B cells. Ectopic p27 expression in a CLL-derived cell line resulted in cell death resistance. Surprisingly, Myc expression was very low or undetectable in most CLL cases analyzed, with a clear correlation between high p27 and low Myc protein levels. This was associated with low Skp2 expression, which is consistent with the Skp2 role in p27 degradation and with SKP2 being a Myc target gene. High Myc expression did not correlate with leukemia progression, despite that cell cycle-related Myc target genes were upregulated. However, biochemical analysis showed that the high p27 levels inhibited cyclin-Cdk complexes even in Myc expressing CLL cells. Our data suggest that the combination of high p27 and low Myc is a marker of CLL cells which is mediated by Skp2.