IL-17 induces radiation resistance of B lymphoma cells by suppressing p53 expression and thereby inhibiting irradiation-triggered apoptosis

Targeting IL-17A enhances imatinib efficacy in Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia

Dysregulated hematopoietic niches remodeled by leukemia cells lead to imbalances in immunological mediators that support leukemogenesis and drug resistance. Targeting immune niches may ameliorate disease progression and tyrosine kinase inhibitor (TKI) resistance in Philadelphia chromosome-positive B-ALL (Ph+ B-ALL). Here, we show that T helper type 17 (Th17) cells and IL-17A expression are distinctively elevated in Ph+ B-ALL patients. IL-17A promotes the progression of Ph+ B-ALL. Mechanistically, IL-17A activates BCR-ABL, IL6/JAK/STAT3, and NF-kB signalling pathways in Ph+ B-ALL cells, resulting in robust cell proliferation and survival. In addition, IL-17A-activated Ph+ B-ALL cells secrete the chemokine CXCL16, which in turn promotes Th17 differentiation, attracts Th17 cells and forms a positive feedback loop supporting leukemia progression. These data demonstrate an involvement of Th17 cells in Ph+ B-ALL progression and suggest potential therapeutic options for Ph+ B-ALL with Th17-enriched niches.

The IL-17 family in diseases: from bench to bedside

The interleukin-17 (IL-17) family comprises six members (IL-17A-17F), and recently, all of its related receptors have been discovered. IL-17 was first discovered approximately 30 years ago. Members of this family have various biological functions, including driving an inflammatory cascade during infections and autoimmune diseases, as well as boosting protective immunity against various pathogens. IL-17 is a highly versatile proinflammatory cytokine necessary for vital processes including host immune defenses, tissue repair, inflammatory disease pathogenesis, and cancer progression. However, how IL-17 performs these functions remains controversial. The multifunctional properties of IL-17 have attracted research interest, and emerging data have gradually improved our understanding of the IL-17 signaling pathway. However, a comprehensive review is required to understand its role in both host defense functions and pathogenesis in the body. This review can aid researchers in better understanding the mechanisms underlying IL-17's roles in vivo and provide a theoretical basis for future studies aiming to regulate IL-17 expression and function. This review discusses recent progress in understanding the IL-17 signaling pathway and its physiological roles. In addition, we present the mechanism underlying IL-17's role in various pathologies, particularly, in IL-17-induced systemic lupus erythematosus and IL-17-related tumor cell transformation and metastasis. In addition, we have briefly discussed promising developments in the diagnosis and treatment of autoimmune diseases and tumors.

A meta-learning approach to improving radiation response prediction in cancers

PURPOSE

Predicting the efficacy of radiotherapy in individual patients has drawn widespread attention, but the limited sample size remains a bottleneck for utilizing high-dimensional multi-omics data to guide personalized radiotherapy. We hypothesize the recently developed meta-learning framework could address this limitation.

METHODS AND MATERIALS

By combining gene expression, DNA methylation, and clinical data of 806 patients who had received radiotherapy from The Cancer Genome Atlas (TCGA), we applied the Model-Agnostic Meta-Learning (MAML) framework to tasks consisting of pan-cancer data, to obtain the best initial parameters of a neural network for a specific cancer with smaller number of samples. The performance of meta-learning framework was compared with four traditional machine learning methods based on two training schemes, and tested on Cancer Cell Line Encyclopedia (CCLE) and Chinese Glioma Genome Atlas (CGGA) datasets. Moreover, biological significance of the models was investigated by survival analysis and feature interpretation.

RESULTS

The mean AUC (Area under the ROC Curve) [95% confidence interval] of our models across nine cancer types was 0.702 [0.691-0.713], which improved by 0.166 on average over other the four machine learning methods on two training schemes. Our models performed significantly better (p < 0.05) in seven cancer types and performed comparable to the other predictors in the rest of two cancer types. The more pan-cancer samples were used to transfer meta-knowledge, the greater the performance improved (p < 0.05). The predicted response scores that our models generated were negatively correlated with cell radiosensitivity index in four cancer types (p < 0.05), while not statistically significant in the other three cancer types. Moreover, the predicted response scores were shown to be prognostic factors in seven cancer types and eight potential radiosensitivity-related genes were identified.

CONCLUSIONS

For the first time, we established the meta-learning approach to improving individual radiation response prediction by transferring common knowledge from pan-cancer data with MAML framework. The results demonstrated the superiority, generalizability, and biological significance of our approach.

Construction of tandem diabody (IL-6/CD20)-secreting human umbilical cord mesenchymal stem cells and its experimental treatment on diffuse large B cell lymphoma

BACKGROUND

More than 40% patients with diffuse large B cell lymphoma (DLBCL) experienced relapse or refractory (R/R) lymphoma after the standard first R-CHOP therapy. IL-6 was reportedly associated with chemotherapy resistance of rituximab. Further, mesenchymal stem cells (MSCs) are known as the potential cell vehicle for their tropism toward tumor. A MSCs-based tandem diabody for treating DLBCL is currently lacking.

METHODS

We constructed a tandem diabody (Tandab(IL-6/CD20)) with modified umbilical cord MSCs (UCMSCs) and designed a cell-based Tandab releasing system. Western blot, qPCR and immunofluorescence were used to confirm the construction and expression of lentivirus-infected UCMSCs. The vitality, apoptosis and homing abilities of UCMSCs were examined via CCK-8 assay, apoptosis, wound healing and migration analysis. Cell binding assay was used to demonstrate the targeting property of Tandab binding to CD20-positive DLBCL cells. Furthermore, we evaluated the viability of SU-DHL-2 and SU-DHL-4 by using CCK-8 and EDU assay after the treatment of UCMSCs-Tandab(IL-6/CD20).

RESULTS

Tandab protein peaked at 6273 ± 487 pg/ml in the medium on day 7 after cell culture. The proliferation and homing ability of UCMSCs did not attenuate after genetically modification. Immunofluorescence images indicated the Tandab protein bound to the lymphoma cells. UCMSCs-Tandab(IL-6/CD20) inhibited the growth of SU-DHL-2 or SU-DHL-4 cells in vitro.

CONCLUSIONS

UCMSCs-Tandab(IL-6/CD20), which bound with both tumor-associated surface antigens and pro-tumor cytokines in tumor microenvironment, might serve as a potential treatment for DLBCL, evidenced by inhibiting the growth of SU-DHL-2 or SU-DHL-4 cells.

Epithelial p53 Status Modifies Stromal-Epithelial Interactions During Basal-Like Breast Carcinogenesis

Basal-like breast cancers (BBC) exhibit subtype-specific phenotypic and transcriptional responses to stroma, but little research has addressed how stromal-epithelial interactions evolve during early BBC carcinogenesis. It is also unclear how common genetic defects, such as p53 mutations, modify these stromal-epithelial interactions. To address these knowledge gaps, we leveraged the MCF10 progression series of breast cell lines (MCF10A, MCF10AT1, and MCF10DCIS) to develop a longitudinal, tissue-contextualized model of p53-deficient, pre-malignant breast. Acinus asphericity, a morphogenetic correlate of cell invasive potential, was quantified with optical coherence tomography imaging, and gene expression microarrays were performed to identify transcriptional changes associated with p53 depletion and stromal context. Co-culture with stromal fibroblasts significantly increased the asphericity of acini derived from all three p53-deficient, but not p53-sufficient, cell lines, and was associated with the upregulation of 38 genes. When considered as a multigene score, these genes were upregulated in co-culture models of invasive BBC with increasing stromal content, as well as in basal-like relative to luminal breast cancers in two large human datasets. Taken together, stromal-epithelial interactions during early BBC carcinogenesis are dependent upon epithelial p53 status, and may play important roles in the acquisition of an invasive morphologic phenotype.

FDG PET/CT parameters and correlations with tumor-absorbed doses in a phase 1 trial of 177Lu-lilotomab satetraxetan for treatment of relapsed non-Hodgkin lymphoma

Purpose

¹⁷⁷Lu-lilotomab satetraxetan targets the CD37 antigen and has been investigated in a first-in-human phase 1/2a study for relapsed non-Hodgkin lymphoma (NHL). Tumor dosimetry and response evaluation can be challenging after radioimmunotherapy (RIT). Changes in FDG PET/CT parameters after RIT and correlations with tumor-absorbed doses has not been examined previously in patients with lymphoma. Treatment-induced changes were measured at FDG PET/CT and ceCT to evaluate response at the lesion level after treatment, and correlations with tumor-absorbed doses were investigated.

Methods

Forty-five tumors in 16 patients, with different pre-treatment and pre-dosing regimens, were included. Dosimetry was performed based on multiple SPECT/CT images. FDG PET/CT was performed at baseline and at 3 and 6 months. SUV_max, MTV, TLG, and changes in these parameters were calculated for each tumor. Lesion response was evaluated at 3 and 6 months (PET_3months and PET_6months) based on Deauville criteria. Anatomical changes based on ceCT at baseline and at 6 and 12 months were investigated by the sum of perpendiculars (SPD).

Results

Tumor-absorbed doses ranged from 35 to 859 cGy. Intra- and interpatient variations were observed. Mean decreases in PET parameters from baseline to 3 months were ΔSUV_max-3months 61%, ΔMTV_3months 80%, and ΔTLG_3months 77%. There was no overall correlation between tumor-absorbed dose and change in FDG PET or ceCT parameters at the lesion level or significant difference in tumor-absorbed doses between metabolic responders and non-responders after treatment.

Conclusion

Our analysis does not show any correlation between tumor-absorbed doses and changes in FDG PET or ceCT parameters for the included lesions. The combination regimen, including cold antibodies, may be one of the factors precluding such a correlation. Increased intra-patient response with increased tumor-absorbed doses was observed for most patients, implying individual variations in radiation sensitivity or biology.

Trial registration

ClinicalTrials.gov Identifier (NCT01796171). Registered December 2012

Supplementary Information

The online version contains supplementary material available at 10.1007/s00259-020-05098-x.

Comparison of time and dose dependent gene expression and affected pathways in primary human fibroblasts after exposure to ionizing radiation

Background

Exposure to ionizing radiation induces complex stress responses in cells, which can lead to adverse health effects such as cancer. Although a variety of studies investigated gene expression and affected pathways in human fibroblasts after exposure to ionizing radiation, the understanding of underlying mechanisms and biological effects is still incomplete due to different experimental settings and small sample sizes. Therefore, this study aims to identify the time point with the highest number of differentially expressed genes and corresponding pathways in primary human fibroblasts after irradiation at two preselected time points.

Methods

Fibroblasts from skin biopsies of 15 cell donors were exposed to a high (2Gy) and a low (0.05Gy) dose of X-rays. RNA was extracted and sequenced 2 h and 4 h after exposure. Differentially expressed genes with an adjusted p-value < 0.05 were flagged and used for pathway analyses including prediction of upstream and downstream effects. Principal component analyses were used to examine the effect of two different sequencing runs on quality metrics and variation in expression and alignment and for explorative analysis of the radiation dose and time point of analysis.

Results

More genes were differentially expressed 4 h after exposure to low and high doses of radiation than after 2 h. In experiments with high dose irradiation and RNA sequencing after 4 h, inactivation of the FAT10 cancer signaling pathway and activation of gluconeogenesis I, glycolysis I, and prostanoid biosynthesis was observed taking p-value (< 0.05) and (in) activating z-score (≥2.00 or ≤ − 2.00) into account. Two hours after high dose irradiation, inactivation of small cell lung cancer signaling was observed. For low dose irradiation experiments, we did not detect any significant (p < 0.05 and z-score ≥ 2.00 or ≤ − 2.00) activated or inactivated pathways for both time points.

Conclusions

Compared to 2 h after irradiation, a higher number of differentially expressed genes were found 4 h after exposure to low and high dose ionizing radiation. Differences in gene expression were related to signal transduction pathways of the DNA damage response after 2 h and to metabolic pathways, that might implicate cellular senescence, after 4 h. The time point 4 h will be used to conduct further irradiation experiments in a larger sample.

Role of heterogeneous regulatory T cells in the tumor microenvironment

Regulatory T cells (Tregs) modulate ongoing immune responses to prevent autoimmunity in healthy bodies and inhibit effective anti-tumor immunity responses in tumor patients, leading to tumor progression. The function of Tregs in tumor immunity suggests that elimination of Tregs in the host may enhance the anti-tumor immune response. Despite the success of strategies for depleting Tregs in tumor-bearing patients, the overall clinical efficacy is limited and accompanied by undesirable side effects. The present review describes the diverse anti-tumor roles and differentiation mechanisms of heterogeneous Tregs and proposes methods for modulating them in the tumor microenvironment. This information is critical for improving clinical outcomes and preventing adverse effects in cancer patients receiving immunotherapy targeting Tregs.

Correlation between IL-17A expression in nasopharyngeal carcinoma tissues and cells and pathogenesis of NPC in endemic areas

OBJECTIVE

We investigated the correlation between the expression of IL-17A in nasopharyngeal carcinoma tissues and cells and the occurrence and development of NPC was also investigated.

METHODS

Forty-five NPC biopsy specimens from January 2014 to January 2016 were selected. Forty-five NPC tissue specimens and 45 chronic nasopharyngitis tissue samples were detected by immunohistochemistry. Statistical methods were used to analyze the correlation between IL-17A expression and the clinicopathological variables of NPC. The NPC patients were followed up. The levels of IL-17A mRNA in 40 NPC tissue specimens and 45 chronic nasopharyngitis tissue samples were detected by real-time PCR. IL-17A expression in 15 NPC tissue specimens and chronic nasopharyngitis tissue samples was further detected by Western blotting assays.

RESULTS

IL-17A expression in NPC tissues was significantly higher than that of chronic nasopharyngitis tissues (P < 0.05). IL-17A was expressed in the nucleus and cytoplasm of both NPC tissues and chronic nasopharyngitis tissues. Stage III + IV NPC, tumor volume ≥ 50 mm, and hepatic envelope invasion and cervical lymph node metastasis were associated with significantly higher IL-17A levels versus stage I + II NPC, tumor size < 50 mm, no membrane invasion and lack of cervical lymph node metastasis (P < 0.05). IL-17A was statistically associated with tissue differentiation, serum EBV-lgA levels, and EBV infection. IL-17A-positive patients had significantly longer median survival versus IL-17A-negative patients (21.0 vs. 13.0 months, log-rank test: P < 0.05). Furthermore, 65% (26/40) of NPC tissue samples had significantly higher IL-17A mRNA levels than chronic nasopharyngitis (P < 0.05). IL-17A expression was significantly higher in NPC ≥ 50 mm, stage III + IV NPC and NPC with cervical lymph node invasion than its corresponding chronic nasopharyngitis tissue.

CONCLUSION

IL-17A may be involved in the regulation of various malignant biological behaviors of NPC, which is closely related to the occurrence and development of NPC.

Human bone marrow-derived mesenchymal stem cells promote the growth and drug-resistance of diffuse large B-cell lymphoma by secreting IL-6 and elevating IL-17A levels

Background

The drug-resistance and relapse of diffuse large B-cell lymphoma (DLBCL), which are related to mesenchymal stem cells (MSCs), have become increasingly common. However, the underlying mechanisms remain elusive.

Methods

CCK 8 assay, colony formation assay, and xenograft mouse model were used to investigate the effects of hBMSCs on DLBCL growth. Immunohistochemistry, qRT-PCR, and ELISA were used to study the expressions of IL-6 and IL-17A. Flow cytometry was used to analyze Th17 cells and Treg cells expressions. Western blot analysis, microarray analysis, and bioinformatics analysis were used to analyze the pathways of IL-6 or IL-17A mediated DLBCL growth.

Results

HBMSCs promoted DLBCL growth by secreting IL-6 in vitro and in vivo and simultaneously upregulating IL-17A in vitro. IL-6 and IL-17A synergistically promoted the growth and drug-resistance of DLBCL cells by protecting them from spontaneous or drug-induced apoptosis in vitro. IL-6 or IL-17A activated the JAK2/STAT3 pathway or upregulated cyclin D2 via activation of PI3K/Akt signaling in vitro, respectively.

Conclusions

The present results indicated that hBMSCs might have a “dual effect” on promoting DLBCL progression and drug-resistance by secreting IL-6 and upregulating IL-17A. IL-6, IL-17A, p-STAT3, p-Akt or cyclin D2 may be potential molecular targets for overcoming drug-resistance in patients with relapsed or refractory DLBCL.

Erythropoietin inhibits chemotherapy-induced cell death and promotes a senescence-like state in leukemia cells

There are conflicting reports on the adverse effects of erythropoietin (EPO) for the management of cancer-associated anemia. The recognition that erythropoietin receptors (EPORs) are expressed outside the erythroid lineage and concerns that erythropoiesis-stimulating agents (ESAs) may cause tumors to grow and increase the risk of venous thromboembolism have resulted in substantially fewer cancer patients receiving ESA therapy to manage myelosuppressive chemotherapy. In this study, we found that EPO suppresses p53-dependent apoptosis induced by genotoxic (daunorubicin, doxorubicin, and γ-radiation) and non-genotoxic (nutlin-3a) agents and induces a senescence-like state in myeloid leukemia cells. EPO interferes with stress-dependent Mdm2 downregulation and leads to the destabilization of p53 protein. EPO selectively modulates the expression of p53 target genes in response to DNA damage preventing the induction of a number of noncoding RNAs (ncRNAs) previously associated with p53-dependent apoptosis. EPO also enhances the expression of the cyclin-dependent kinase inhibitor p21^WAF1 and promotes recruitment of p53 to the p21 promoter. In addition, EPO antagonizes Mcl-1 protein degradation in daunorubicin-treated cells. Hence, EPO signaling targets Mcl-1 expression and the p53-Mdm2 network to promote tumor cell survival.

Granulocyte-colony-stimulating factor-producing metaplastic carcinoma of the breast with significant elevation of serum interleukin-17 and vascular endothelial growth factor levels

Granulocyte-colony-stimulating factor (G-CSF) production in carcinomas is associated with a very aggressive phenotype. Interleukin (IL)-17 secreted from tumor-infiltrating lymphocytes induces the production of G-CSF and vascular endothelial growth factor (VEGF) in cancer tissue. We present a case of a G-CSF-producing metaplastic breast carcinoma (MpBC) accompanied by systemic elevation of IL-17 and VEGF levels. A 56-year-old woman presented with a rapidly growing tumor measuring > 10 cm in her left breast. Core needle biopsy confirmed the diagnosis as MpBC with triple-negative features. Diffuse fluorodeoxyglucose uptake in the long bones and marked leukocytosis suggested that the G-CSF was produced by the primary tumor, which showed upregulated G-CSF mRNA and protein levels. Multiplex cytokine assessment identified increased serum IL-17, VEGF, and G-CSF levels. After radical mastectomy and skin grafting, the leukocyte count and serum G-CSF, IL-17, and VEGF levels were normalized. She underwent postmastectomy radiotherapy (50 Gy/25 Fr) and adjuvant chemotherapy (90 mg/m² of epirubicin and 600 mg/m² of cyclophosphamide followed by 80 mg/m² of paclitaxel) and is alive without recurrence. This is the first in vivo observation that describes the systemic elevation of IL-17 and VEGF levels with concomitant G-CSF production. Further research is warranted to study the IL-17/G-CSF/VEGF axis as a potential therapeutic target for this aggressive type of breast cancer.

Increased expression of IRF8 in tumor cells inhibits the generation of Th17 cells and predicts unfavorable survival of diffuse large B cell lymphoma patients

The immunological pathogenesis of diffuse large B cell lymphoma (DLBCL) remains elusive. Searching for new prognostic markers of DLBCL is a crucial focal point for clinical scientists. The aim of the present study was to examine the prognostic value of interferon regulatory factor 8 (IRF8) expression and its effect on the development of Th17 cells in the tumor microenvironment of DLBCL patients. Flow cytometry, immunohistochemistry, and quantitative real-time PCR were used to detect the distribution of Th17 cells and related cytokines and IRF8 in tumor tissues from DLBCL patients. Two DLBCL cell lines (OCI-LY10 and OCI-LY1) with IRF8 knockdown or overexpression and two human B lymphoblast cell lines were co-cultured with peripheral blood mononuclear cells (PBMCs) in vitro to determine the effect of IRF8 on the generation of Th17 cells. Quantitative real-time PCR and Western blotting were used to investigate the involvement of retinoic acid receptor-related orphan receptor gamma t (RORγt) in the effect of IRF8 on Th17 cell generation. The survival of 67 DLBCL patients was estimated using the Kaplan-Meier method and log-rank analysis. The percentage of Th17 cells was lower in DLBCL tumor tissues than in PBMCs and corresponding adjacent benign tissues. Relative expression of interleukin (IL)-17A was lower, whereas that of interferon (IFN)-γ was higher in tumor tissues than in benign tissues. Co-culture with DLBCL cell lines inhibited the generation of Th17 cells in vitro. IRF8 upregulation was detected in DLBCL tumor tissues, and it was associated with decreased DLBCL patient survival. Investigation of the underlying mechanism suggested that IRF8 upregulation in DLBCL, through an unknown mechanism, inhibited Th17 cell generation by suppressing RORγt in neighboring CD4+ T cells. Tumor cells may express soluble or membrane-bound factors that inhibit the expression of RORγt in T cells within the tumor microenvironment. Our findings suggest that IRF8 expression could be a prognostic factor for DLBCL.

Increased interleukin-17A levels promote rituximab resistance by suppressing p53 expression and predict an unfavorable prognosis in patients with diffuse large B cell lymphoma

Rituximab resistance has become increasingly common in patients with diffuse large B cell lymphoma (DLBCL). However, the mechanisms involved remain unclear. In this study, we aimed to examine the effect of rituximab on interleukin (IL)-17A and to investigate the role of IL-17A in rituximab resistance and its prognostic value in patients with DLBCL. Our retrospective analysis revealed that rituximab increased IL-6 expression levels in patients with DLBCL, and the increased IL-6 levels in turn induced the differentiation of Th17 and IL-17⁺Foxp3⁺ Treg cells, which secreted IL-17A both in vivo and in vitro. We then examined the effects of IL-17A on the apoptosis and proliferation of, and p53 expression in DLBCL cells, and found that IL-17A prevented rituximab-induced apoptosis and promoted the proliferation of DLBCL cells by suppressing p53 expression in vitro. The survival data of 73 patients with DLBCL suggested that high peripheral blood levels of IL-17A predicted an unfavorable survival. On the whole, our data indicate that rituximab promotes Th17 and IL-17⁺Foxp3⁺ Treg cells to secrete IL-17A, which in turn promotes rituximab resistance, partially by suppressing p53 expression and inhibiting rituximab-induced DLBCL cell apoptosis. IL-17A may thus prove to be a useful prognostic marker in patients with DLBCL.

MicroRNA-150 enhances radiosensitivity by inhibiting the AKT pathway in NK/T cell lymphoma

Background

Radioresistance is a major challenge during the treatment of NK/T cell lymphoma. This study aimed to investigate the potential role of MicroRNA-150 (miR-150) in increase the sensitivities of NK/T cell lymphoma to ionizing radiation.

Results

In this study, we found that miR-150 was significantly decreased in NK/T cell lymphoma tissues and cell lines. Low expression of miR-150 was positively associated with therapeutic resistance in 36 NK/T cell lymphoma cases. Our further in vitro and in vivo studies illustrated that overexpression of miR-150 substantially enhanced the sensitivity of NK/T cell lymphoma cells to ionizing radiation treatment. Furthermore, luciferase reporter assays in NK/T cell lymphoma cells transfected with the AKT2 or AKT3 three prime untranslated region reporter constructs established AKT2 and AKT3 as direct targets of miR-150. The phosphatidylinositol 3-kinase inhibitor LY294002 was used to inhibit Akt to verify miR-150 increase NK/T cell lymphoma cell radiorsensitivity through suppress the PI3K/AKT/mTOR pathway.

Conclusions

Taken together, this study demonstrates that miR-150 might serve as a potential therapeutic sensitizer through inhibition of the AKT pathway in NK/T cell lymphoma treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0639-5) contains supplementary material, which is available to authorized users.

The long noncoding RNA-ROR promotes the resistance of radiotherapy for human colorectal cancer cells by targeting the p53/miR-145 pathway

BACKGROUND AND AIM

Long intergenic noncoding RNAs (lincRNAs) have critical roles in elevating efficacy of anticancer therapy and tumor progression. Recent studies show that Regulator of Reprogramming (ROR) is aberrantly expressed in several types of cancer, including colorectal cancer (CRC). Radiotherapy is considered as a standard preoperative treatment. However, a considerable number of CRCs are resistant to radiotherapy. In this study, we evaluated the role of lincRNA-ROR in radiotherapy for CRC and detected the underlying molecular mechanism.

METHODS

Real-time polymerase chain reaction was employed to quantify the expression level of lincRNA-ROR in different CRC cell lines and tissue samples. Cell viability and apoptosis assays were used to confirm the radiotherapy-mediated effects by lincRNA-ROR altered expression. The direct impact of lincRNA-ROR on the expression of p53/miR-145 by loss-of-function and gain-of-function strategy was also analyzed. A xenograft mouse model was used to evaluate the role of linc-ROR in CRC treatment.

RESULTS

We discovered that lincRNA-ROR was upregulated in CRC cell lines and tissue samples. We further showed that knockdown of lincRNA-ROR enhanced the sensitivity to radiotherapy for CRC by inhibiting cell viability and promoting apoptosis. Activity of the p53/miR-145 pathway may help explain the role of lincRNA-ROR for stress-induced regulation in CRC therapy. Combined specific knockdown of lincRNA-ROR and radiotherapy treatment in xenograft model resulted in a significant reduction in the tumor growth.

CONCLUSION

LincRNA-ROR decreases sensitivity to radiotherapy via the negative regulation of p53/miR-145 and may represent a potential target for the treatment of CRC.

Cholecystokinin attenuates radiation-induced lung cancer cell apoptosis by modulating p53 gene transcription

The deregulation of p53 in cancer cells is one of the important factors by which cancer cells escape from the immune surveillance. Cholecystokinin (CCK) has strong bioactivity in the regulation of a number of cell activities. This study tests a hypothesis that CCK interferes with p53 expression to affect the apoptotic process in lung cancer (tumor) cells. In this study, tumor-bearing mice and A549 cells (a tumor cell line) were irradiated. The expression of CCK and p53 in tumor cells was assessed with RT-qPCR and Western blotting. The binding of p300 to the promoter of p53 was evaluated by chromatin immunoprecipitation. We observed that, with a given amount and within a given period, small doses/more sessions of irradiation markedly increased the levels of CCK in the sera and tumor cells, which were positively correlated with the tumor growth in mice and negatively correlated with tumor cell apoptosis. CCK increased the levels of histone acetyltransferase p300 and repressed the levels of nuclear factor-kB at the p53 promoter locus in tumor cells, which suppressed the expression of p53. In conclusion, CCK plays an important role in attenuating the radiation-induced lung cancer cell apoptosis. CCK may be a novel therapeutic target in the treatment of lung cancers.

Effects of radiation on T regulatory cells in normal states and cancer: mechanisms and clinical implications

Radiation remains an important component of cancer treatment. In addition to inducing tumor cell death through direct cytotoxic effects, radiation can also promote the regression of tumor via augment of immune response. Regulatory T cells (Tregs) are a unique subpopulation of CD4 positive cells, which are characterized by expression of the forkhead box P3 (Foxp3) transcription factor and high levels of CD25. Mounting evidence has shown that Tregs are implicated in the development and progression of various types of cancer, which makes Tregs an important target in cancer therapeutics. Generally, lymphocytes are regarded as radiosensitive. However, Tregs have been demonstrated to be relatively resistant to radiotherapy, which is partly mediated by downregulation of pro-apoptotic proteins and upregulation of anti-apoptotic proteins. Moreover, radiotherapy can increase the production of Tregs and the recruitment of Tregs to local tumor microenvironment. Tregs can attenuate radiation-induced tumor death, which cause the resistance of tumor to radiotherapy. Recent experimental studies and clinical trails have demonstrated that the combination of radiation with medications that target Tregs is promising in the treatment of several types of neoplasms. In this review, we discussed the effect of radiation on Tregs in physiological states and cancer. Further, we presented an overview of therapies that target Tregs to enhance the efficacy of radiation in cancer therapeutics.

IL-17A Promotes Intracellular Growth of Mycobacterium by Inhibiting Apoptosis of Infected Macrophages

The fate of infected macrophages is a critical aspect of immunity to mycobacteria. By depriving the pathogen of its intracellular niche, apoptotic death of the infected macrophage has been shown to be an important mechanism to control bacterial growth. Here, we show that IL-17 inhibits apoptosis of Mycobacterium bovis BCG- or Mycobacterium tuberculosis-infected macrophages thus hampering their ability to control bacterial growth. Mechanistically, we show that IL-17 inhibits p53, and impacts on the intrinsic apoptotic pathway, by increasing the Bcl2 and decreasing Bax expression, decreasing cytochrome c release from the mitochondria, and inhibiting caspase-3 activation. The same effect of IL-17 was observed in infected macrophages upon blockade of p53 nuclear translocation. These results reveal a previously unappreciated role for the IL-17/p53 axis in the regulation of mycobacteria-induced apoptosis and can have important implications in a broad spectrum of diseases where apoptosis of the infected cell is an important host defense mechanism.