Therapeutic challenge for immunotherapy targeting cold colorectal cancer: A narrative review.

Cold colorectal tumors are not likely to trigger a robust immune response and tend to suppress the immune response. There may be three reasons. First, the complex tumor microenvironment of cold colorectal cancer (CRC) leads to tolerance and clearance of immunotherapy. Second, the modification and concealment of tumor-specific targets in cold CRC cause immune escape and immune response interruption. Finally, the difference in number and function of immune cell subsets in patients with cold CRC makes them respond poorly to immunotherapy. Therefore, we can only overcome the challenges in immunotherapy of cold CRC through in-depth research and understanding the changes and mechanisms in the above three aspects of cold CRC.

[Comparative Study of the Two High-Efficient Strategies for in vitro Generation of Human Umbilical Cord Blood-derived Natural Killer Cells].

OBJECTIVE: To explore the similarities and variations of biological phenotype and cytotoxicity of human umbilical cord blood natural killer cells (hUC- NK) after human umbilical cord blood-derived mononuclear cells (hUC-MNC) activated and expanded by two in vitro high-efficient strategies. METHODS: Umbilical cord blood mononuclear cells (MNC) from healthy donor were enriched by Ficoll-based density gradient centrifugation. Then, the phenotype, subpopulations, cell viability and cytotoxicity of NK cells derived from Miltenyi medium (denoted as M-NK) and X-VIVO 15 (denoted as X-NK) were compared using a "3IL" strategy. RESULTS: After a 14-day's culture, the contents of CD3-CD56+ NK cells were elevated from 4.25%±0.04% (d 0) to 71%±0.18% (M-NK) and 75.2%±1.1% (X-NK) respectively. Compared with X-NK group, the proportion of CD3+CD4+ T cells and CD3+CD56+ NKT cells in M-NK group decreased significantly. The percentages of CD16+, NKG2D+, NKp44+, CD25+ NK cells in X-NK group was higher than those in the M-NK group, while the total number of expanded NK cells in X-NK group was half of that in M-NK group. There were no significant differences between X-NK and M-NK groups in cell proliferation and cell cycle, except for the lower percentage of Annexin V+ apoptotic cells in M-NK group. Compared with X-NK group, the proportion of CD107a+ NK cells in M-NK group were higher under the same effector-target ratio (E∶T) (P<0.05). CONCLUSION: The two strategies were adequate for high-efficient generation of NK cells with high level of activation in vitro, however, there are differences in biological phenotypes and tumor cytotoxicity.

Therapeutic prospects of mesenchymal stem/stromal cells in COVID-19 associated pulmonary diseases: From bench to bedside.

The ongoing outbreak of coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 has become a sudden public emergency of international concern and seriously threatens millions of people's life health. Two current studies have indicated a favorable role for mesenchymal stem/stromal cells (MSCs) in clinical remission of COVID-19 associated pulmonary diseases, yet the systematical elaboration of the therapeutics and underlying mechanism is far from satisfaction. In the present review, we summarize the therapeutic potential of MSCs in COVID-19 associated pulmonary diseases such as pneumonia induced acute lung injury, acute respiratory distress syndrome, and pulmonary fibrosis. Furthermore, we review the underlying mechanism of MSCs including direct- and trans-differentiation, autocrine and paracrine anti-inflammatory effects, homing, and neovascularization, as well as constitutive microenvironment. Finally, we discuss the prospects and supervision of MSC-based cytotherapy for COVID-19 management before large-scale application in clinical practice. Collectively, this review supplies overwhelming new references for understanding the landscapes of MSCs in the remission of COVID-19 associated pulmonary diseases.

[MiR-335-5p-Mediated Dysfunction of T Lymphocytes in Patients with Acquired Aplastic Anemia].

OBJECTIVE: To explore the effect of miR-335-5p/ADCY3 interaction on the lymphocyte function in the patients with aplastic anemia (AA). METHODS: Blood samples were collected from 22 healthy volunteers (HC) and 50 AA patients including 38 severe AA (SAA) and 12 non-severe AA (NSAA). Peripheral blood mononuclear cells (PBMNC) were isolated. The expression of miR-335-5p and ADCY3 mRNA was detected by using RT-PCR. Negative control miR-335-5p (NC group) and miR-335-5p mimic (mimic group) were transfected to AA-PBMNC by using RNAimax reagent, respectively. The proliferative ability, activation and cytokines of CD4+ T and CD8+ T cells were measured by flow cytometry. Dual-luciferase reporter assay was used to verify the targeted relationship between miR-335-5p and target gene. RESULTS: The expression of miR-335-5p was significantly downregulated in SAA-PBMNC and NSAA-PBMNC compared with HC-PBMNC (0.08±0.01 vs 0.74±0.10, P＜0.01; 0.17±0.02 vs 0.74±0.10, P＜0.01). Meanwhile, the expression of miR-335-5p in SAA-PBMNC was very statistically significantly lower than that in NSAA-PBMNC (P＜0.01). Compared with NC group, upregulation of miR-335-5p in vitro could significantly inhibited the proliferation of CD4+ T and CD8+ T cells in AA-PBMNC (P＜0.05 and P＜0.05, respectively). And, upregulating miR-335-5p in AA-PBMNC could significantly inhibited the activation of CD4+ and CD8+ T cells (P＜0.01 and P＜0.01, respectively). The ratio of CD4+TNFα+ T, CD8+IFNγ++T and CD8+TNFα+ T cell by up-regulating the expression of miR-335-5p from AA-PBMNC in vitro was also significantly lower (P＜0.01, P＜0.05 and P＜0.05, respectively). In addition, the expression of ADCY3 was higher in AA-PBMNC than that in HC-PBMNC (1.70±0.15 vs 0.76±0.12, P＜0.01). Furthermore, by means of dual-luciferase reporter assay, the luciferase activity of ADCY3'UTR wildtype could be inhibited by miR-335-5p. CONCLUSIONS: The expression of miR-335-5p was significantly downregulated in AA, and that correlates with disease severity. Up-regulating miR-335-5p can correct the hyperimmune status in AA patients by targeting ADCY3. These changes may relates with the strengthen of inhibition for targeted gene ADCY3.

[DMSO Promotes Hematopoietic Differentiation of Human Embryonic Stem Cells in vitro].

OBJECTIVE: To explore the role of dimethyl sulfoxide (DMSO) in the hematopoietic differentiation of human embryonic stem cells (hESCs). METHODS: The role of DMSO in hematopoietic differentiation of hESC was investigated by using a established stepwise hematopoietic differentiation system from hESC, immunofluorescouse assay and flow cytometry. Furthermore, the window phase of DMSO action was explored by adding it to the different stage of hematopoietic differentiation. RESULTS: Immunofluorescence and flow cytometry analysis showed that DMSO significantly promoted the generation of CD43+ hematopoietic progenitor cells (HPC). The flow cytometry demonstrated that DMSO profoundly promoted the generation of APLNR+ lateral plate mesoderm cells and CD31+CD34+ hemogenic endothelium progenitors (HEP). The addition of DMSO in the window phase of lateral plate mesoderm cell generation could markedly improve the generation of hematopoietic progenitor cells. CONCLUSION: DMSO promotes hematopoietic differentiation of hESC through enhancing the generation of APLNR positive lateral plate mesoderm cells. The addition of DMSO in the window phase of lateral plate mesoderm cell generation can significantly improve the generation of hematopoietic progenitor cells.