Genome-wide CRISPR Screens Reveal Host Factors Critical for SARS-CoV-2 Infection.

Identification of host genes essential for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection may reveal novel therapeutic targets and inform our understanding of coronavirus disease 2019 (COVID-19) pathogenesis. Here we performed genome-wide CRISPR screens in Vero-E6 cells with SARS-CoV-2, Middle East respiratory syndrome CoV (MERS-CoV), bat CoV HKU5 expressing the SARS-CoV-1 spike, and vesicular stomatitis virus (VSV) expressing the SARS-CoV-2 spike. We identified known SARS-CoV-2 host factors, including the receptor ACE2 and protease Cathepsin L. We additionally discovered pro-viral genes and pathways, including HMGB1 and the SWI/SNF chromatin remodeling complex, that are SARS lineage and pan-coronavirus specific, respectively. We show that HMGB1 regulates ACE2 expression and is critical for entry of SARS-CoV-2, SARS-CoV-1, and NL63. We also show that small-molecule antagonists of identified gene products inhibited SARS-CoV-2 infection in monkey and human cells, demonstrating the conserved role of these genetic hits across species. This identifies potential therapeutic targets for SARS-CoV-2 and reveals SARS lineage-specific and pan-CoV host factors that regulate susceptibility to highly pathogenic CoVs.

Genome-scale CRISPR-Cas9 knockout screening in gastrointestinal stromal tumor with Imatinib resistance.

Genome-scale CRISPR-Cas9 Knockout Screening was applied to investigate novel targets in imatinib-resistant gastrointestinal stromal tumor (GIST). 20 genes and 2 miRNAs have been selected by total reads of sgRNA and sgRNA diversity, which has been further validated in imatinib-resistant GIST cells by CCK8 and qPCR analysis. Our study has finally revealed 9 genes (DBP, NR3C1, TCF12, TP53, ZNF12, SOCS6, ZFP36, ACYP1, and DRD1) involved in imatinib-resistant GIST-T1 cells. TP53 and SOCS6 may be the most promising candidate genes for imatinib-resistance due to the possible signaling pathway, such as apoptosis pathway and Wnt signaling pathway, JAK-STAT signaling pathway. It is necessary to perform more studies to discover novel targets in imatinib-resistant GIST, including DBP, NR3C1, TCF12, ZNF12, ZFP36, ACYP1 and DRD1.

Gambogic Acid Efficiently Kills Stem-Like Colorectal Cancer Cells by Upregulating ZFP36 Expression.

BACKGROUND/AIMS: Gambogic acid (GA), the main active compound of Gamboge hanburyi, has been reported to be a potential novel antitumor drug. Whether GA inhibits putative cancer stem cells (CSCs), which are considered to be the major cause of cancer treatment failure, remains largely unknown. This study investigated whether GA inhibits the CSCs of colorectal cancer (CRC) and its possible mechanisms. METHODS: We performed CCK8 and tumor sphere formation assays, percentage analysis of both side population and CD133+CD44+ cells, and the detection of stem cells markers, in order to assess the role of GA in inhibiting the stem celllike features of CRC. An mRNA microarray was performed to identify the downstream gene affected by GA and rescue assays were performed to further clarify whether the downstream gene is involved in the GA induced decrease of the stem cell-like CRC population. CRC cells were engineered with a CSC detector vector encoding GFP and luciferase (Luc) under the control of the Nanog promoter, which were utilized to investigate the effect of GA on putative CSC in human tumor xenograft-bearing mice using in vivo bioluminescence imaging. RESULTS: Our results showed that GA significantly reduced tumor sphere formation and the percentages of side population and CD133+CD44+ cells, while also decreasing the expression of stemness and EMT-associated markers in CRC cells in vitro. GA killed stem-like CRC cells by upregulating the expression of ZFP36, which is dependent on the inactivation of the EGFR/ ERK signaling pathway. GFP+ cells harboring the PNanog-GFP-T2A-Luc transgene exhibited CSC characteristics. The in vivo results showed that GA significantly inhibited tumor growth in nude mice, accompanied by a remarkable reduction in the putative CSC number, based on whole-body bioluminescence imaging. CONCLUSION: These findings suggest that GA significantly inhibits putative CSCs of CRC both in vitro and in vivo by inhibiting the activation of the EGFR/ ERK/ZFP36 signaling pathway and may be an effective drug candidate for anticancer therapies.

Human WDR5 promotes breast cancer growth and metastasis via KMT2-independent translation regulation.

Metastatic breast cancer remains a major cause of cancer-related deaths in women, and there are few effective therapies against this advanced disease. Emerging evidence suggests that key steps of tumor progression and metastasis are controlled by reversible epigenetic mechanisms. Using an in vivo genetic screen, we identified WDR5 as an actionable epigenetic regulator that is required for metastatic progression in models of triple-negative breast cancer. We found that knockdown of WDR5 in breast cancer cells independently impaired their tumorigenic as well as metastatic capabilities. Mechanistically, WDR5 promotes cell growth by increasing ribosomal gene expression and translation efficiency in a KMT2-independent manner. Consistently, pharmacological inhibition or degradation of WDR5 impedes cellular translation rate and the clonogenic ability of breast cancer cells. Furthermore, a combination of WDR5 targeting with mTOR inhibitors leads to potent suppression of translation and proliferation of breast cancer cells. These results reveal novel therapeutic strategies to treat metastatic breast cancer.

Analysis of the pathogenic bacteria, drug resistance, and risk factors of postoperative infection in patients with non-small cell lung cancer.

BACKGROUND: To analyze the pathogenic bacteria, drug resistance, and risk factors of postoperative infection in patients with non-small cell lung cancer (NSCLC). METHODS: A total of 119 patients with NSCLC who were admitted to our hospital from January 2017 to March 2020 were selected. The patients' clinical data were collected to evaluate the postoperative infection. The pathogenic bacteria, drug resistance, and risk factors of postoperative infections in patients with NSCLC were analyzed. RESULTS: Among 119 patients, 33 cases (27.73%) had postoperative infection, and 86 cases (72.28%) had no infection. In total, 81 pathogens were isolated from the secretions via bacterial culture from the infected sites of the 33 patients. Of these, 43 (53.09%) were gram-negative bacteria, 34 (41.98%) were Gram-positive bacteria, and four (4.94%) were fungi. Postoperative gram-negative infection showed the highest resistance rate to ciprofloxacin (81.39%), and the drug resistance rate to imipenem and meropenem was low (9.30% and 4.65%, respectively). Postoperative gram-positive infection exhibited the highest resistance rate to erythromycin (82.35%), and the drug resistance rate to vancomycin was low (5.88%). According to the univariate analysis, there were differences between the two groups in age, length of hospitalization, combined diseases, operation time, invasive procedures, hemoglobin, and serum albumin (P<0.05). However, there were no differences in terms of gender, TNM staging, and pathological classification (P<0.05). Based on the unconditional multivariate logistic regression model analysis, age ≥60 years, hospitalization time >30 d, combined diseases, operation time ≥3 h, hospitalization time >30 d, invasive operation, hemoglobin ≤90 g/L, and serum albumin ≤30 g/L were independent risk factors leading to postoperative infection in patients with NSCLC (P<0.05). CONCLUSIONS: The postoperative infection rate of patients with NSCLC is high. gram-negative bacteria infection is the primary infection in patients. There are many factors that cause postoperative infections in patients, and it is necessary to strictly control these risk factors in clinical practice, which is an effective means to prevent postoperative infection.

Genome-wide CRISPR screen reveals host genes that regulate SARS-CoV-2 infection.

Identification of host genes essential for SARS-CoV-2 infection may reveal novel therapeutic targets and inform our understanding of COVID-19 pathogenesis. Here we performed a genome-wide CRISPR screen with SARS-CoV-2 and identified known SARS-CoV-2 host factors including the receptor ACE2 and protease Cathepsin L. We additionally discovered novel pro-viral genes and pathways including the SWI/SNF chromatin remodeling complex and key components of the TGF-ß signaling pathway. Small molecule inhibitors of these pathways prevented SARS-CoV-2-induced cell death. We also revealed that the alarmin HMGB1 is critical for SARS-CoV-2 replication. In contrast, loss of the histone H3.3 chaperone complex sensitized cells to virus-induced death. Together this study reveals potential therapeutic targets for SARS-CoV-2 and highlights host genes that may regulate COVID-19 pathogenesis.

Long noncoding RNA PVT1-214 promotes proliferation and invasion of colorectal cancer by stabilizing Lin28 and interacting with miR-128.

Long noncoding RNAs (lncRNAs) are implicated in human cancer, but their mechanisms of action are largely unknown. In this study, we investigated lncRNA alterations that contribute to colorectal cancer (CRC) through microarray expression profiling in CRC patient samples. Here, we report that the CRC-associated lncRNA PVT1-214 is a key regulator of CRC development and progression; patients with high PVT1-214 expression had a shorter survival and poorer prognosis. In vitro and in vivo investigation of the role of PVT1-214 revealed a complex integrated phenotype affecting cell growth, stem-like properties, migration, and invasion. Furthermore, using RNA pull-down and mass spectrometry, we found that Lin28 (also known as Lin28A), a highly conserved RNA-binding protein, is associated with PVT1-214. Strikingly, we found that PVT1-214 not only upregulated Lin28 protein expression in CRC cells by stabilizing Lin28, but also participated in crosstalk with Lin28 mRNA through competition for miR-128 binding, imposing an additional level of post-transcriptional regulation. In addition, we further show that PVT1-214 repressed expression of let-7 family miRNAs, which was abrogated by Lin28 knockdown. Taken together, our findings support a model in which the PVT1-214/Lin28/let-7 axis serves as a critical regulator of CRC pathogenesis, which may simulate a new direction for CRC therapeutic development.

PD-L1 promotes colorectal cancer stem cell expansion by activating HMGA1-dependent signaling pathways.

PD-L1 is critical for tumor cell escape from immune surveillance by inhibiting T cell function via the PD-1 receptor. Accumulating evidence demonstrates that anti-PD-L1 monoclonal antibodies might potently enhance antitumor effects in various tumors, but the effect of PD-L1 on colorectal cancer stem cells (CSCs) remains unclear. We observed high PD-L1 expression in CD133+CD44+ colorectal CSCs and CSC-enriched tumorspheres. Altering PD-L1 expression promoted colorectal CSC self-renewal by increasing the expression of stemness genes, the CD133+CD44+ cell population sizes and the ability to form tumorspheres. Additionally, PD-L1 expression was markedly increased in chemoresistant colorectal cancer (CRC) cells in vitro and in vivo. More importantly, PD-L1 enhanced CRC cell tumorigenicity in nude mice; the inoculation of 1 × 104 cells resulted in high tumor formation efficiency. Mechanistically, PD-L1 directly interacted with HMGA1, and HMGA1 upregulation by PD-L1 activated HMGA1-dependent pathways, including the PI3K/Akt and MEK/ERK pathways, and promoted CSC expansion. HMGA1 downregulation rescued the PD-L1-induced phenotypes, highlighting the role of HMGA1 in PD-L1-mediated colorectal CSC self-renewal. Moreover, PD-L1 expression was correlated with the expression of CSC markers and HMGA1 in clinical CRC specimens. Thus, PD-L1 could crucially contribute to the maintenance of CSC self-renewal by activating HMGA1-dependent signaling pathways.

Expression of EZH2 is associated with poor outcome in colorectal cancer.

Enhancer of zeste homolog 2 (EZH2), the critical component of polycomb group protein family, has been demonstrated to be overexpressed in various types of human cancer, including hepatocellular carcinoma, breast, bladder and lung cancer. The mechanism of how EZH2 promotes oncogenesis has also been well studied. However, little is known about the role of EZH2 in colorectal cancer (CRC). The main purpose of the present study was to analyze the association between EZH2 expression and the clinicopathological features of CRC. Therefore, the mRNA and protein expression levels were analyzed in tumor tissues and adjacent non-cancerous tissues by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analysis. The expression of EZH2 was demonstrated to be significantly increased in tumor tissues compared with adjacent noncancerous tissues, according to the results of western blot analysis and RT-qPCR in the majority of cases. Patients with low EZH2 expression had a longer overall survival rate compared with those with high EZH2 expression. An analysis of the association between clinicopathological features and EZH2 expression indicated that high EZH2 expression was significantly associated with tumor stage, tumor size, histological differentiation and lymph node metastasis. Multivariate analysis demonstrated that high EZH2 expression was an independent predictor of overall survival. In conclusion, to the best of our knowledge, the data presented in the present study is the first to indicate that EZH2 is upregulated in CRC and may serve as a predictor of poor outcome for patients with CRC.

Overexpression of flavin-containing monooxygenase 5 predicts poor prognosis in patients with colorectal cancer.

The present study investigated the expression and clinical significance of flavin-containing monooxygenase 5 (FMO5) in colorectal cancer (CRC). The expression of FMO5 was detected by immunohistochemistry in 208 colon cancer tissues and 8 normal colon tissues. Then, the correlations of FMO5 expression with several clinicopathological features were evaluated. FMO5 mRNA expression from The Cancer Genome Atlas dataset was assessed for further validation. In addition, the association of the expression of FMO5 with prognosis was further evaluated by Kaplan-Meier survival curves and Cox proportional hazards model. The FMO5 protein level in colon cancer tissues was significantly higher than that in normal colon tissues (P<0.001). Overexpression of FMO5 was associated with an advanced clinical stage of cancer (P=0.018) and lymph node metastasis (P=0.03). The TCGA dataset also demonstrated that FMO5 was upregulated in CRC with advanced clinical stage (P=0.047), lymph node metastasis (P=0.045) and distant metastasis (P=0.030). The Kaplan-Meier survival curves showed that higher FMO5 mRNA indicated a shorter overall survival in patients with CRC compared with a low expression of FMO5 (P=0.029). Cox proportional hazards regression revealed that a high FMO5 mRNA level served as an independent prognostic factor for patients with CRC (hazard ratio, 2.865; 95% confidence interval, 1.116-7.355; P=0.029). A high expression of FMO5 may serve roles in colorectal carcinogenesis and distant metastasis. FMO5 may be an independent predictive factor for the prognosis of CRC.

Long non­coding RNA 00152 functions as a competing endogenous RNA to regulate NRP1 expression by sponging with miRNA­206 in colorectal cancer.

Colorectal cancer (CRC) is the third most common type of cancer; however, the molecular mechanisms underlying colorectal tumor metastasis and growth remain elusive. Recently, accumulating evidence has indicated that long non­coding RNAs (lncRNAs) play a critical role in CRC progression and metastasis; however, the biological role and clinical significance of lncRNA 00152 (lnc00152) in CRC remains largely unknown. Thus, in this study, lnc00152 expression was measured in 80 human CRC tissue samples, 40 non­cancerous tissue samples, and 3 CRC cell lines (SW480, SW620 and LoVo) using RT­qPCR. We examined the effects of lnc00152 on CRC cells following transfection with lnc00152 overexpression plasmid or respective siRNA in vitro and in vivo. Luciferase assays revealed the mechanism driving competitive endogenous RNA (ceRNA). We identified that lnc00152 was aberrantly overexpressed in colorectal tumors and cancer cells and that lnc00152 was modulated by miRNA­206. lnc00152 overexpression enhanced the proliferative and invasive ability of CRC cells in vitro, promoted tumor growth in vivo, and was associated with the shorter overall survival of patients with CRC. In addition, lnc00152 overexpression promoted epithelial-mesenchymal transition (EMT) and increased neuropilin­1 (NRP1) expression in the CRC cells. By contrast, lnc00152 silencing exerted a counteractive effect. Collectively, these findings demonstrate the critical role of lnc00152 in tumor growth and progression in CRC, and identify a novel therapeutic target associated with CRC development and progression.

Gambogic acid potentiates the chemosensitivity of colorectal cancer cells to 5-fluorouracil by inhibiting proliferation and inducing apoptosis.

Chemotherapy using 5-fluorouracil (5-FU) for colorectal cancer (CRC) has low specificity and response rates, leading to severe side effects. Gambogic acid (GA), a traditional Chinese medicine, has multi-targeted anticancer effects, including growth inhibition and apoptosis induction. However, it is unclear whether a combination of 5-FU and GA has synergistic anticancer effects in CRC cells. In this study, SW480 and HCT116 human CRC cells and human intestinal epithelial cells (IECs) were treated with different concentrations of 5-FU, GA or 5-FU+GA. A Cell Counting kit-8 assay was conducted to quantify cell proliferation. The combination index (CI) was calculated and the median-effect principle was applied to analyze the interaction between 5-FU and GA. Flow cytometry was used to determine the percentage of cells undergoing apoptosis. Reverse transcription-quantitative polymerase chain reaction and western blotting were applied to measure P53, survivin and thymidylate synthase (TS) mRNA and protein levels. It was found that 5-FU+GA more pronouncedly inhibited cell growth and induced apoptosis, compared with either monotherapy. CI values <1 indicated the synergistic effects of the drugs. 5-FU+GA further decreased P53, survivin and TS mRNA and protein levels in the two CRC cell lines compared with single drugs, whereas increased P53 protein levels were observed in HCT116 cells. Moreover, 5-FU+GA did not increase cytotoxicity to IECs. These results demonstrate that GA enhances the anticancer effects of 5-FU on CRC cells. Combined treatment with 5-FU and GA is effective and safe for CRC cells, and may become a promising chemotherapy treatment.

Overexpression of transcription factor activating enhancer binding protein 4 (TFAP4) predicts poor prognosis for colorectal cancer patients.

Transcription factor activating enhancer binding protein 4 (TFAP4) is an important regulator in the genesis and progression of human cancers. Overexpression of TFAP4 has been found to be correlated with several malignancies. The present study assessed the clinical importance of TFAP4 in colorectal cancer (CRC). First, immunohistochemistry was used to analyze TFAP4 expression and the association of TFAP4 expression with clinicopathological features on a tissue microarray containing 208 CRC patients. The results revealed that TFAP4 protein expression was significantly upregulated in CRC tissues compared with that in normal colon tissues (P<0.001). Of note, statistical analysis revealed that TFAP4 expression was significantly correlated with a high pathological grade (P=0.034), advanced clinical stage (P=0.024), enhanced tumor invasion (P=0.002) and lymph node metastasis (P=0.041). In addition, the Cancer Genome Atlas dataset further validated that TFAP4 mRNA levels were increased in CRC with advanced clinical stage (P=0.026), lymph node metastasis (P=0.018) and vascular invasion (P=0.046). Kaplan-Meier survival analysis demonstrated that CRC patients with high TFAP4 expression had shorter overall survival compared with those with low TFAP4 expression (P=0.011). Importantly, overexpression of TFAP4 was a valuable independent prognostic factor for CRC patients (hazard ratio, 8.200; 95% confidence interval, 1.838-36.591; P=0.006). In summary, TFAP4 may have an important role in CRC progression and upregulation of TFAP4 may be a predictor of poor prognosis for CRC patients.

[Effect of interleukin 17 on invasion of human colon cancer cells].

OBJECTIVE: To investigate the effect and its possible mechanism of interleukin-17 (IL-17) on invasion and metastasis of human colon cancer cells. METHODS: IL-17 was added into the culture media of human colon cancer cells SW480 and LOVO. Cells were divided into 4 groups: SW480 control group (SW480 cells), LOVO control group (LOVO cells), SW480 experiment group (50 µg/L IL-17+SW480 cells), and LOVO experiment group (50 µg/L IL-17+LOVO cells). Cell growth was measured by CCK-8 assay. The proliferation rate(%)=[(Aexperiment group-Ablank)/(Acontrol group-Ablank)]×100%). The ability of cell invasion and migration was measured by transwell assay. Real time-PCR was used to detect mRNA expression of VEGF and MMP-9. Western blot was performed to detect protein expression of STAT3, p-STAT3, VEGF and MMP-9. Enzyme-linked immunosorbent assay (ELISA) was applied to measure the protein content of VEGF and MMP-9 in the supernatant. RESULTS: After cultivation for 24, 48 and 72 hours, CCK-8 assay revealed that the proliferation rate of SW480 was 1.18%±0.07%, 1.42%±0.09%, and 1.62%±0.08%; the proliferation rate of LOVO was 1.13%±0.02%, 1.32%±0.05% and 1.73%±0.02% in experiment group. Transwell experiments showed that after cultivation with IL-17 for 24 hours, number of invasion cell in experimental groups (SW480: 34.00±0.45, LOVO: 41.60±0.51) was higher as compared to corresponding control groups (SW480: 4.53±0.14; LOVO: 3.67±0.33) with significant differences (SW480: t=-76.026, P=0.001; LOVO: t=-81.580, P=0.005). The number of migration cell in experimental groups (SW480: 36.40±0.51, LOVO: 46.40±0.68) was higher as compared to corresponding control groups (SW480: 7.83±0.69; LOVO: 6.67±0.48) with significant differences (SW480: t=-51.542, P=0.003; LOVO: t=-49.265, P=0.005). Real-time PCR results revealed that after cultivation with IL-17 for 24 hours, VEGF and MMP-9 mRNA relative expression levels in experimental groups (SW480: VEGF:1.53±0.12, MMP-9: 2.44±0.23; LOVO: VEGF: 2.96±0.35, MMP-9: 3.38±0.55) were higher than those in control groups (both 1) with significant differences (VEGF: t=3.799, P=0.043; MMP-9: t=5.254, P=0.039). Western blot illustrated that after cultivation with IL-17 for 24 hours, STAT3, p-STAT3, VEGF and MMP-9 proteins relative expression levels in experimental groups were significantly higher that those in control groups (SW480:STAT3: t=3.233, P=0.023; p-STAT3: t=3.954, P=0.032; VEGF: t=3.201, P=0.025; MMP-9: t=3.154, P=0.029; LOVO: STAT3: t=3.788, P=0.012; p-STAT3: t=2.662, P=0.040; VEGF: t=4.118, P=0.035; MMP-9: t=4.268, P=0.030). ELISA indicated that content of VEGF and MMP-9 in the supernatant of experimental groups (SW480: VEGF 5 491.41±63.22, MMP-9: 21.43±1.35. LOVO: VEGF: 8 631.46±129.59, MMP-9: 178.32±3.20) were higher than those in control groups (SW480: VEGF:4 456.32±87.56, MMP-9:18.57±2.44. LOVO: VEGF: 8 122.38±108.66, MMP-9: 163.22±6.89) with significant differences (SW480: VEGF: t=6.993, P=0.037; MMP-9: t=5.587, P=0.040. LOVO: VEGF: t=7.013, P=0.044; MMP-9: t=6.762, P=0.043). CONCLUSION: IL-17 may be able to activate STAT3 signal transduction pathway in vitro through up-regulation of VEGF and MMP-9 expression, thereby enhancing the invasion and migration of colon cancer SW480 and LOVO cells.

Gankyrin sustains PI3K/GSK-3ß/ß-catenin signal activation and promotes colorectal cancer aggressiveness and progression.

High levels of angiogenesis, metastasis and chemoresistance are major clinical features of colorectal cancer (CRC), a lethal disease with a high incidence worldwide. Aberrant activation of Wnt/ß-catenin pathway contributes to CRC progression. However, little is known about regulatory mechanisms of the ß-catenin activity in cancer progression. Here we report that Gankyrin was markedly upregulated in primary tumor tissues from CRC patients and was associated with poor survival. Moreover, we demonstrated that overexpressing Gankyrin promoted, while knockdown of Gankyrin impaired, the aggressive phenotype of proliferation, angiogenesis, chemoresistance and metastasis of CRC cells both in vitro and in vivo. Importantly, we found a unique molecular mechanism of Gankyrin in CRC cells signaling transduction, that regulated the cross-talk between PI3K/Akt and Wnt/ß-catenin signaling pathways, sustaining PI3K/GSK-3ß/ß-catenin signal activation in CRC. Therefore, these findings not only reveal a mechanism that promotes aggressiveness and progression in CRC, but also provide insight into novel molecular targets for antitumor therapy in CRCs.