Chemokines in progression, chemoresistance, diagnosis, and prognosis of colorectal cancer.

Plenty of factors affect the oncogenesis and progression of colorectal cancer in the tumor microenvironment, including various immune cells, stromal cells, cytokines, and other factors. Chemokine is a member of the cytokine superfamily. It is an indispensable component in the tumor microenvironment. Chemokines play an antitumor or pro-tumor role by recruitment or polarization of recruiting immune cells. Meanwhile, chemokines, as signal molecules, participate in the formation of a cross talk among signaling pathways and non-coding RNAs, which may be involved in promoting tumor progression. In addition, they also function in immune escape. Chemokines are related to drug resistance of tumor cells and may even provide reference for the diagnosis, therapy, and prognosis of patients with colorectal cancer.

Bioinformatics analysis of KLF2 as a potential prognostic factor in ccRCC and association with epithelial-mesenchymal transition.

Clear cell renal cell carcinoma (ccRCC) is a primary pathological subtype of RCC and has poor clinical outcome. Krüppel-like factors (KLFs), which are zinc-finger proteins, may be involved in ccRCC development and progression. KLFs belong to the zinc-finger family of DNA-binding transcription factors and regulate transcription of downstream target genes. KLFs are involved in cancer development. The present study aimed to investigate the role of KLFs in ccRCC prognosis. The Cancer Genome Atlas database and multifactorial analysis showed that KLFs were widely expressed in pan-cancers and KLF2 was an independent protective factor for ccRCC prognosis. Patients with low KLF2 expression had a low survival probability and expression of KLF2 was downregulated in patients with ccRCC with high pathological grade (II + III vs. I). In addition, western blot and reverse transcription-quantitative PCR revealed that KLF2 was expressed at low levels in ccRCC cell lines and overexpression of KLF2 inhibited cell migration. In addition, KLF2 expression was negatively correlated with methylation. KLF2 expression was elevated following treatment of ccRCC cells with DNA methyltransferase inhibitor. A prognostic risk index prediction model was constructed based on multiple Cox regression. The receiver operating characteristic curve was 0.780 (area under curve >0.5). Furthermore, Gene Ontology enrichment analysis showed that 'cell adhesion' and 'junction' were negatively correlated with KLF2 and that high-risk group exhibited significantly activated 'epithelial-mesenchymal transition'. Western blot analysis showed that overexpression of KLF2 increased expression of E-cadherin, while decreasing levels of N-cadherin and vimentin. The present study highlighted the role of KLFs in ccRCC prognosis prediction and provides a research base for the search of validated prognostic biological markers for ccRCC.

Exocyst controls exosome biogenesis via Rab11a.

Tumor cells actively release large quantities of exosomes, which pivotally participate in the regulation of cancer biology, including head and neck cancer (HNC). Exosome biogenesis and release are complex and elaborate processes that are considered to be similar to the process of exocyst-mediated vesicle delivery. By analyzing the expression of exocyst subunits and their role in patients with HNC, we aimed to identify exocyst and its functions in exosome biogenesis and investigate the molecular mechanisms underlying the regulation of exosome transport in HNC cells. We observed that exocysts were highly expressed in HNC cells and could promote exosome secretion in these cells. In addition, downregulation of exocyst expression inhibited HN4 cell proliferation by reducing exosome secretion. Interestingly, immunofluorescence and electron microscopy revealed the accumulation of multivesicular bodies (MVBs) after the knockdown of exocyst. Autophagy, the major pathway of exosome degradation, is not activated by this intracellular accumulation of MVBs, but these MVBs are consumed when autophagy is activated under the condition of cell starvation. Rab11a, a small GTPase that is involved in MVB fusion, also interacted with the exocyst. These findings suggest that the exocyst can regulate exosome biogenesis and participate in the malignant behavior of tumor cells.

Inhibition of hsa_circ_0003489 shifts balance from autophagy to apoptosis and sensitizes multiple myeloma cells to bortezomib via miR-874-3p/HDAC1 axis.

BACKGROUND: Circular RNAs (circRNAs) crucially regulate tumor progression. In this study, we examined the functional roles and mechanisms of hsa_circ_0003489 in multiple myeloma (MM). METHODS: Upon altering the expressions of hsa_circ_0003489, miR-874-3p, and/or histone deacetylase 1 (HDAC1) in MM1.R cells and treating them with bortezomib (BTZ), cell viability was examined by CCK-8 assay; cell proliferation by Ki-67 immunofluorescence; apoptosis by TUNEL staining, flow cytometry, and western blot; and autophagy by electron microscopy and western blot. The interaction between hsa_circ_0003489 and miR-874-3p as well as that between miR-874-3p and HDAC1 was examined by expressional analysis, dual luciferase reporter assay, and RNA immunoprecipitation. The in vivo impacts of hsa_circ_0003489 on MM growth and sensitivity to BTZ were examined using an MM xenograft mouse model. RESULTS: Knocking down hsa_circ_0003489 significantly inhibited the viability, cell proliferation, and autophagy, while promoting the apoptosis of MM cells in vitro and MM xenograft in vivo. Suppressing hsa_circ_0003489 also further boosted the cytotoxic effects of BTZ in MM cells and reversed its promoting effect on autophagy. Mechanically, hsa_circ_0003489 acted as a sponge of miR-874-3p and positively regulated the expression of miR-874-3p target, HDAC1. MiR-874-3p and HDAC1 essentially mediated the effects of hsa_circ_0003489 on cell viability, proliferation, apoptosis, and autophagy. CONCLUSION: The hsa_circ_0003489/miR-874-3p/HDAC1 axis critically regulates the balance between apoptosis and autophagy. Silencing hsa_circ_0003489 sensitizes MM cells to BTZ by inhibiting autophagy and thus may boost the therapeutic effects of BTZ.

Microbial antigens-loaded myeloma cells enhance Th2 cell proliferation and myeloma clonogenicity via Th2-myeloma cell interaction.

BACKGROUND: Myeloma cells retain B cell functions, considered to be potential antigen presenting cells, yet there is little information regarding promoting Th2 cell proliferation or the direct effects to myeloma on the Th2 cells stimulated by microbial antigens-loaded myeloma cells. METHODS: Mixed lymphocyte reaction was used colorimetric assays via CCK8-kit. Surface molecular expression was performed by flow cytometry, cells sorting using microbeads. The concentrations of cytokines in serum were assessed using an ELISA kit. Clonogenic assay were performed in a methylcellulose culture system. Statistical analysis was assessed using the Student's t-test or one-way analysis of variance for multiple comparisons test. RESULTS: The expression of HLA-DR, CD80 and CD40 on RPMI8266 cell membrane surface was upregulated by interaction with interferon-γ and/or Bacillus Calmette-Guerin Vaccine (BCGV). RPMI8266 cells were able to induce the mixed lymphocyte reaction in a dose-dependent fashion. The Th2 ratio induced by RPMI8266 treated by BCGV and interferon-γ (treated-RPMI8266) cells was only slightly greater than by untreated-tumor cells, but the serum IL-4 level secreted by Th2 cells was markedly higher in treated-RPMI8266 cells group. Th2 cells stimulated by treated-myeloma cells could directly promote treated-myeloma cell clonogenicity in a dose-dependent manner. Anti-HLADR IgG2b completely blocked increased of IL-4 secretion by Th2 cells stimulated by treated-myeloma cells, while also blocked enhancing the clonogenicity of treated tumor cells stimulated by MM-Th2 cells. CONCLUSIONS: These results indicate that a novel mechanism of myeloma pathogenesis in myeloma cells could act as an APC to present microbial Ags to Th2 cells, promoting Th2 cell proliferation, consequently facilitating tumor development by close interaction between Th2 myeloma cells. Taken together, the microbial Ag presenting course of MM-Th2-MM interactions-restricted by MHC class-II-may result in tumor development such that all factors involved in the system could have a potential for myeloma therapeutic intervention.

[Corrigendum] MicroRNA­497 inhibits multiple myeloma growth and increases susceptibility to bortezomib by targeting Bcl­2.

Subsequently to the publication of the article, the authors have realized that the second and third author affiliations were presented the wrong way around, and should have been reversed. Therefore, the author affiliations in this paper should have appeared as follows: Faqing Tian1, Yong Zhan2, Wei Zhu3, Juheng Li1, Meiqin Tang1, Xiaohui Chen1 and Jian Jiang1. Departments of 1Hematology and 2Radiology, Longgang District People's Hospital of Shenzhen, Shenzhen, Guangdong 518172; 3Department of Pathology, School of Basic Medicine, Guangdong Medical University, Dongguan, Guangdong 523808, P.R. China. The authors regret that these errors and omissions were not corrected prior to the publication of the paper, and apologize to the readership for the inconvenience caused. [the original article was published in International Journal of Molecular Medicine 43: 1058­1066, 2019; DOI: 10.3892/ijmm.2018.4019].

MicroRNA-497 inhibits multiple myeloma growth and increases susceptibility to bortezomib by targeting Bcl-2.

Multiple myeloma (MM) is a common severe hematopoietic malignancy occuring in aged population. MicroRNA (miR)­497 was previously reported to contribute to the apoptosis of other cell types, presumably through targeting B­cell lymphoma 2 (Bcl­2). In the present study, miRNA and protein expression levels were detected by reverse transcription­quantitative polymerase chain reaction and western blot analyses, respectively. The cell proliferation and viability was measured using 3­(4,5­dimethylthiazol­2­yl)­2, 5­diphenyltetrazolium bromide and plate clonality assays, and the cell growth cycle was measured with a flow cytometer. Terminal deoxynucleotidyl transferase (TdT)­mediated dUTP nick­end­labeling, Annexin V and caspase­3 activity assays were performed to examine the cell apoptotic rates. The results showed that miR­497 was markedly decreased, whereas Bcl­2 was enhanced in MM tissues and cell lines. miR­497 targeted Bcl­2 and affected its downstream apoptosis­related genes. The overexpression of miR­497 promoted MM cell apoptosis through cell cycle arrest, and decreased colony genesis ability and viability. In addition, miR­497 increased the sensitivity of MM cells to bortezomib. Taken together, miR­497 suppressed MM cell proliferation and promoted apoptosis by directly targeting Bcl­2 and altering the expression of downstream apoptosis­related proteins. The combination of miR­497 and bortezomib may enhance drug sensitivity, serving as a potentially available therapeutic method for MM.

The antibiotic chloramphenicol may be an effective new agent for inhibiting the growth of multiple myeloma.

Chloramphenicol is an old antibiotic that also inhibits mammalian mitochondrial protein synthesis. Our studies demonstrated that chloramphenicol is highly cytotoxic to myeloma cells, acting in a dose- and time-dependent manner. Chloramphenicol sharply suppressed ATP levels in myeloma cells at concentrations ≥ 25 µg/mL. Colorimetric and clonogenic assays indicate that chloramphenicol inhibits growth of myeloma cell lines at concentrations ≥ 50 µg/mL, and inhibits primary myeloma cell growth at concentrations ≥ 25 µg/mL. Flow cytometry and Western blotting showed that chloramphenicol induces myeloma cell apoptosis at concentrations ≥ 50 µg/mL. Chloramphenicol increased levels of cytochrome c, cleaved caspase-9 and cleaved caspase-3, suggesting that myeloma cell apoptosis occurs through the mitochondria-mediated apoptosis pathway. It thus appears chloramphenicol is not only an old antibiotic, it is also a potential cytotoxic agent effective against myeloma cells. This suggests chloramphenicol may be an effective "new" drug for the treatment of myeloma.

[Induction of dendritic cells derived from acute promyelocytic leukemia cells by all trans retinoic acid].

This study was purposed to investigate the possibility of differentiating the acute promyelocytic leukemia (APL) cells into dendritic cells (DCs) induced by all-trans retinoic acid (ATRA) combined with classic cytokines so as to provide a new approach for development of APL-DC vaccine. The bone marrow mononuclear cells from a new diagnosed patient with APL and HL-60 cells were separately cultured in complete culture medium. The cells were treated by ATRA, GM-CSF, IL-4 and TNFalpha in experimental groups and no ATRA was added in control and blank control groups. The cell morphology was observed by light microscopy, the phenotypes of DCs were detected by flow cytometry, the level of IL-12 was measured by using ELISA, the mixed lymphocyte reaction (MLR) and effect of cytotoxic T-lymphocyte (CTL) were assayed by MTT method. The results indicated that in experiment groups, the cells had dendritic appearance and cytogenetic characteristics of APL; expression of CD1a, CD83, CD80, CD86, HLA-DR and CD1d as well as level of IL-12 obviously increased; the MLR and CTL effects were significant, but increase of CD1a expression in HL60-DCs did not show statistical difference from control and blank control groups. It is concluded that ATRA can successfully induce APL cells to differentiate into functionally mature DSs which obviously mediate MLR and CTL effects. The APL-DCs derived by ATRA can notably express CD1d that may activate CD1d-restricted NKT cells and promote proliferation of NRT cells. The exact mechanism of which should be further studied.

[Effect of PD-L1 blockade on function of dendritic cells derived from chronic myelocytic leukemia].

Programmed death-1 ligand-1(PD-L1) is a recently identified member of the B7 family molecules and is shown to mediate the inhibition of immune responses. This study was purposed to enhance the weak immunological function of dendritic cells (DCs) derived from the patients with chronic myelocytic leukemia (CML) by blockade of the expression of PD-L1. Bone marrow mononuclear cells (BMMNCs) of CML patients were induced into DCs in the presence of cytokine cocktail of rhGM-CSF, rhIL-4 and TNF-alpha. The phenotypes of DCs were detected by flow cytometry, mixed lymphocyte reaction was analyzed by MTT assay and IFN-gamma, IL-2 and IL-10 in the cell culture supernatant were detected by ELISA. The results showed that the expression of PD-L1 on CML-DCs was upregulated with the maturation of CML-DCs. PD-L1-blockaded DCs could enhance T lymphocyte proliferation, increase the secretion of IL-2 and IFN-gamma, and inhibit the production of IL-10. Taken together, PD-L1-blockaded DCs originated from CML cells had more potent immunostimulatory capability. It is concluded that PD-L1 blockaded can enhance the function of CML-DCs. This approach presents new possibilities for achieving anti-tumor immunity by DC-based vaccination.