scholarly journals CRISPR screens identify cholesterol biosynthesis as a therapeutic target on stemness and drug resistance of colon cancer

Oncogene ◽  
2021 ◽  
Author(s):  
Shanshan Gao ◽  
Fraser Soares ◽  
Shiyan Wang ◽  
Chi Chun Wong ◽  
Huarong Chen ◽  
...  

AbstractCancer stem cells (CSCs) are responsible for tumor progression, recurrence, and drug resistance. To identify genetic vulnerabilities of colon cancer, we performed targeted CRISPR dropout screens comprising 657 Drugbank targets and 317 epigenetic regulators on two patient-derived colon CSC-enriched spheroids. Next-generation sequencing of pooled genomic DNAs isolated from surviving cells yielded therapeutic candidates. We unraveled 44 essential genes for colon CSC-enriched spheroids propagation, including key cholesterol biosynthetic genes (HMGCR, FDPS, and GGPS1). Cholesterol biosynthesis was induced in colon cancer tissues, especially CSC-enriched spheroids. The genetic and pharmacological inhibition of HMGCR/FDPS impaired self-renewal capacity and tumorigenic potential of the spheroid models in vitro and in vivo. Mechanistically, HMGCR or FDPS depletion impaired cancer stemness characteristics by activating TGF-β signaling, which in turn downregulated expression of inhibitors of differentiation (ID) proteins, key regulators of cancer stemness. Cholesterol and geranylgeranyl diphosphate (GGPP) rescued the growth inhibitory and signaling effect of HMGCR/FDPS blockade, implying a direct role of these metabolites in modulating stemness. Finally, cholesterol biosynthesis inhibitors and 5-FU demonstrated antitumor synergy in colon CSC-enriched spheroids, tumor organoids, and xenografts. Taken together, our study unravels novel genetic vulnerabilities of colon CSC-enriched spheroids and suggests cholesterol biosynthesis as a potential target in conjunction with traditional chemotherapy for colon cancer treatment.

2021 ◽  
Author(s):  
xingang wang ◽  
YAN ZHENG ◽  
YU WANG

Abstract Background and AimsPseudopodium-enriched atypical kinase 1 (PEAK1) has reported to be upregulated in human malignancies and related with poor prognosis. Enhanced PEAK1 expression facilitates tumor cell survival, invasion, metastasis and chemoresistance. However, the role of PEAK1 in breast cancer is not clear. Here, we investigated the PEAK1 expression in breast cancer and analyzed its relation with clinicopathological status and chemotherapy resistance to the neoadjuvant chemotherapy (NAC). We also investigated the role of PEAK1 on breast cancer cells in vitro and in vivo. MethodsImmunohistochemistry (IHC) was performed in 112 surgical resected breast cancer tissues. The associations between clinicopathological status, multi-drug resistance and PEAK1 expression were determined. Effect of PEAK1 overexpression or down-expression on proliferation, colony formation, invasion, migration, metastasis and Doxorubicin sensitivity in the MCF-7 cells in vitro and in vivo was detected. ResultsPEAK1 was overexpressed in breast cancer tissues and NAC -resistant breast cancer tissues. High PEAK1 expression was related with tumor size, high tumor grade, T stage, LN metastasis, recurrence, Ki-67 expression, Her-2 expression and multi-drug resistance. Targeting PEAK1 inhibited cell growth, invasion, metastasis and reversed chemoresistance to Doxorubicin in breast cancer cells in vitro and in vivo. ConclusionHigh PEAK1 expression was associated with invasion, metastasis and chemoresistance of breast cancers. Furthermore, targeting PEAK1 could inhibit cell growth and metastasis, and reverse chemoresistance in breast cancer cells, which provides an effective treatment strategies for breast cancer.


2021 ◽  
Vol 11 ◽  
Author(s):  
Yibin Zhao ◽  
Hongyi Zhou ◽  
Jie Shen ◽  
Shaohui Yang ◽  
Ke Deng ◽  
...  

BackgroundDysregulated microRNAs (miRNAs) are common in human cancer and are involved in the proliferation, promotion, and metastasis of tumor cells. Therefore, this study aimed to evaluate the expression and biological function of miR-1236-3p in colon cancer.MethodsThis study screened the miRNA in normal and colon cancer tissues through array analysis. In addition, quantitative Reverse Transcription–Polymerase Chain Reaction (qRT-PCR) analysis was performed to validate the expression of miR-1236-3p in normal and tumor tissues from colon cancer patients and cancer cell lines. Online predicting algorithms and luciferase reporter assays were also employed to confirm Doublecortin Like Kinase 3 (DCLK3) was the target for miR-1236-3p. Moreover, the impact of miR-1236-3p on the progression of colon cancer was evaluated in vitro and in vivo. Western blotting and qRT-PCR were also performed to investigate the interactions between miR-1236-3p and DCLK3.ResultsMiR-1236-3p was significantly downregulated in colon cancer tissues and its expression was associated with the TNM stage and metastasis of colon. In addition, the in vitro and in vivo experiments showed that miR-1236-3p significantly promoted cancer cell apoptosis and inhibited the proliferation, invasion, and migration of cancer cells. The results also showed that miR-1236-3p hindered Epithelial–mesenchymal Transition (EMT) by targeting DCLK3. Moreover, the expression of DCLK3 mediated the effects of miR-1236-3p on the progression of cancer.ConclusionsMiR-1236-3p functions as a tumor suppressor in colon cancer by targeting DCLK3 and is therefore a promising therapeutic target for colon cancer.


2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Yifan Li ◽  
Jing Xun ◽  
Botao Wang ◽  
Yuan Ma ◽  
Lanqiu Zhang ◽  
...  

Abstract Background Colorectal cancer is one of the most common malignancy in the world. It has been reported that cancer stem cells (CSCs) serve as the primary drivers of tumorigenesis and tumor progression. There is an urgent need to explore novel molecules that regulate CSCs or their signatures. Increasing evidence has shown that miRNAs are involved in tumorigenesis and progression. Here, we aim to explore the regulatory effect and mechanism of miR-3065-3p on the stemness of colorectal cancer. Methods The expression of miR-3065-3p in colorectal cancer and the association of miR-3065-3p expression with prognosis of patients with colorectal cancer were analyzed using TCGA dataset or clinical cases. Gain or loss of function in different models, including colorectal cancer cell lines and orthotopic xenograft or liver metastatic mouse model, were used to investigate the effects of miR-3065-3p on colorectal cancer stemness and metastasis in vitro and in vivo. Cancer stemness was analyzed by detecting the ability of migration and invasion, NANOG, OCT4, and SOX2 expression, ALDH activity and sphere formation. In addition, the interaction of miR-3065-3p and cytokine receptor-like factor 1 (CRLF1) was analyzed theoretically and identified by the luciferase reporter assay. Moreover, the correlation between CRLF1 expression and miR-3065-3p was analyzed in colorectal cancer tissues. Finally, the effect of CRLF1 on the stemness and metastasis of colorectal cancer in vitro and in vivo was assessed. Results In this report, we found that miR-3065-3p was overexpressed in colorectal cancer and that its high expression was associated with poor prognosis of patients with colorectal cancer. miR-3065-3p promotes the stemness and metastasis of colorectal cancer. Furthermore, CRLF1 was the downstream target of miR-3065-3p and inhibited the stemness of colorectal cancer. In addition, CRLF1 expression was negatively correlated with miR-3065-3p in colorectal cancer tissues. And, CRLF1 mediated the effects of miR-3065-3p on promoting stemness of colorectal cancer cells. Conclusion Our data suggest that miR-3065-3p promoted the stemness and metastasis of colorectal cancer by targeting CRLF1. miR-3065-3p might serve as a promising prognostic marker as well as a therapeutic target for colorectal cancer.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bi-Qing Cai ◽  
Wan-Meng Chen ◽  
Jia Zhao ◽  
Wei Hou ◽  
Jian-Cai Tang

Increasing evidence indicates that nuclear factor, erythroid 2-like 3 (Nrf3) is connected with tumorigenesis. However, the relationship between Nrf3 and tumor drug resistance remains elusive. In this study, we investigated the effect and mechanism of action by which Nrf3 regulated the sensitivity of colon cancer cells to 5-fluorouracil (5-FU). We found Nrf3 was significantly increased in colon cancer tissues. Furthermore, we observed that Nrf3 knockdown and overexpression can significantly affect the sensitivity of colon cancer cells to 5-FU in vitro and in vivo. Moreover, Nrf3 promoted the expression of RELA, P-RELA, and BCL-2. Inhibition of NF-κB partly reversed the effects of Nrf3 overexpression, resulting in the resistance of colon cancer cells to 5-FU. Overall, the study revealed that Nrf3 was connected to the sensitivity of colon cancer cells to 5-FU, and its possible mechanism was related to the NF-κB signaling pathway, which provided a new target for overcoming the resistance of colon cancer cells to 5-FU.


2021 ◽  
Vol 10 ◽  
Author(s):  
Zhuo-Xun Wu ◽  
Yuqi Yang ◽  
Leli Zeng ◽  
Harsh Patel ◽  
Letao Bo ◽  
...  

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Irinotecan is widely used as a chemotherapeutic drug to treat CRC. However, the mechanisms of acquired resistance to irinotecan in CRC remain inconclusive. In the present study, we established a novel irinotecan-resistant human colon cell line to investigate the underlying mechanism(s) of irinotecan resistance, particularly the overexpression of ABC transporters. The irinotecan-resistant S1-IR20 cell line was established by exposing irinotecan to human S1 colon cancer cells. MTT cytotoxicity assay was carried out to determine the drug resistance profile of S1-IR20 cells. The drug-resistant cells showed about 47-fold resistance to irinotecan and cross-resistance to ABCG2 substrates in comparison with S1 cells. By Western blot analysis, S1-IR20 cells showed significant increase of ABCG2, but not ABCB1 or ABCC1 in protein expression level as compared to that of parental S1 cells. The immunofluorescence assay showed that the overexpressed ABCG2 transporter is localized on the cell membrane of S1-IR20 cells, suggesting an active efflux function of the ABCG2 transporter. This finding was further confirmed by reversal studies that inhibiting efflux function of ABCG2 was able to completely abolish drug resistance to irinotecan as well as other ABCG2 substrates in S1-IR20 cells. In conclusion, our work established an in vitro model of irinotecan resistance in CRC and suggested ABCG2 overexpression as one of the underlying mechanisms of acquired resistance to irinotecan. This novel resistant cell line may enable future studies to overcome drug resistance in vitro and improve CRC treatment in vivo.


2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Wenying Tian ◽  
Wenjia Zhang ◽  
Yan Zhang ◽  
Tianyue Zhu ◽  
Yuting Hua ◽  
...  

Abstract Background The prognosis of colon cancer is poor for metastasis, while the mechanism, especially adipocytes related, is not yet clear. The purpose of this study is to determine the effects of fatty acid binding protein 4 (FABP4), a transporter for lipids, on colon cancer progression. Methods The distribution of lipids and FABP4 was tested in the colon cancer tissues and adjacent normal tissues, and their relationship was also verified in vitro. Experiments about cellular invasion, migration and proliferation were performed to detect the impacts of FABP4 on the biological behaviors of colon cancer, and the positive results were checked in vivo. Meanwhile, the regulatory role of FABP4 in the energy and lipid metabolism was evaluated by the levels of triglyceride, ATP, LDH, glycerol and NEFA. At last, GO and KEGG analysis based on FABP4 overexpressed cells was performed, and the AKT pathway and epithelial–mesenchymal transition (EMT)-related proteins were determined by Western blot. Results Higher accumulation of lipids and stronger FABP4 transcription were observed in colon cancer tissues. Having been incubated with adipose tissue extract and overexpressed FABP4, colon cancer cells demonstrated enhanced lipid accumulation. In functional experiments, co-culture with adipose tissue extract significantly enhanced the invasion and migration of colon cancer cells, as well as the energy and lipid metabolism, and all these processes were reversed by FABP4 inhibitor. In addition, the metastasis of FABP4-overexpressed colon cancer cells was also significantly enhanced in vitro and in vivo. In terms of mechanism, the bioinformatics analysis showed that FABP4 was enriched in 11 pathways related to metabolic processes in FABP4 overexpressed cells. Finally, FABP4 overexpression improved EMT progression of colon cancer, as evidenced by the upregulation of Snail, MMP-2 and MMP-9, the downregulation of E-cadherin. The expression of p-Akt was also elevated. Conclusion FABP4 overexpression could increase FAs transport to enhance energy and lipid metabolism, and activate AKT pathway and EMT to promote the migration and invasion of colon cancer cells.


Cancers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 755 ◽  
Author(s):  
Abril Saint-Martin ◽  
Jacobo Martínez-Ríos ◽  
M. Cristina Castañeda-Patlán ◽  
Miguel Angel Sarabia-Sánchez ◽  
Nydia Tejeda-Muñoz ◽  
...  

Hypoxia and the accumulation of hypoxia-inducible factors (HIFs) in tumors have been associated with therapeutic resistance and with autophagy establishment. We examined the effects of stable knockdown of HIF-1α or HIF-2α expression on autophagy and drug resistance in colon cancer cells. We found that under normoxic conditions, malignant cells exhibit increased basal levels of autophagy, compared with non-malignant cells, in addition to the previously reported coexpression of HIF-1α and HIF-2α. Knockdown of HIF-1α or HIF-2α expression resulted in increased autophagic and apoptotic cell death, indicating that the survival of cells is HIF-dependent. Cytotoxic-induced cell death was significantly increased by knockdown of HIFs but not by autophagy inhibition. Strikingly, although malignancy-resistant cells were sensitized to death by nutrient stress, the combination with HIF-2α depletion, but not with HIF-1α depletion, induced severe cell death. Oxidative stress levels were significantly increased as a result of HIF-2α specific inhibition or silencing suggesting that this may contribute to sensitize cells to death. The in vitro results were confirmed in vivo using a xenograft mouse model. We found that coordinated autophagy and mTOR inhibition enhanced cell death and induced tumor remission only in HIF-2α-silenced cells. Finally, using a specific HIF-2α inhibitor alone or in combination with drugs in patient-derived primary colon cancer cells, overcame their resistance to 5-FU or CCI-779, thus emphasizing the crucial role played by HIF-2α in promoting resistance and cell survival.


2021 ◽  
Vol 12 (5) ◽  
Author(s):  
Mushtaq A. Nengroo ◽  
Shrankhla Maheshwari ◽  
Akhilesh Singh ◽  
Ayushi Verma ◽  
Rakesh K. Arya ◽  
...  

AbstractChemokine receptor CXCR4 overexpression in solid tumors has been strongly associated with poor prognosis and adverse clinical outcome. However, blockade of CXCL12-CXCR4 signaling axis by inhibitors like Nox-A12, FDA approved CXCR4 inhibitor drug AMD3100 have shown limited clinical success in cancer treatment. Therefore, exclusive contribution of CXCR4-CXCL12 signaling in pro-tumorigenic function is questionable. In our pursuit to understand the impact of chemokine signaling in carcinogenesis, we reveal that instead of CXCR4-CXCL12 signaling, presence of CXCR4 intracellular protein augments paclitaxel resistance and pro-tumorigenic functions. In search of pro-apoptotic mechanisms for CXCR4 mediated drug resistance; we discover that DR5 is a new selective target of CXCR4 in breast and colon cancer. Further, we detect that CXCR4 directs the differential recruitment of transcription factors p53 and YY1 to the promoter of DR5 in course of its transcriptional repression. Remarkably, inhibiting CXCR4-ligand-mediated signals completely fails to block the above phenotype. Overexpression of different mutant versions of CXCR4 lacking signal transduction capabilities also result in marked downregulation of DR5 expression in colon cancer indeed confirms the reverse relationship between DR5 and intracellular CXCR4 protein expression. Irrespective of CXCR4 surface expression, by utilizing stable gain and loss of function approaches, we observe that intracellular CXCR4 protein selectively resists and sensitizes colon cancer cells against paclitaxel therapy in vitro and in vivo. Finally, performing TCGA data mining and using human breast cancer patient samples, we demonstrate that expression of CXCR4 and DR5 are inversely regulated. Together, our data suggest that targeting CXCR4 intracellular protein may be critical to dampen the pro-tumorigenic functions of CXCR4.


2020 ◽  
Author(s):  
Anup Kumar Singh ◽  
Ayushi Verma ◽  
Akhilesh Singh ◽  
Rakesh Kumar Arya ◽  
Shrankhla Maheshwari ◽  
...  

AbstractDrug resistance is one of the trademark features of Cancer Stem Cells (CSCs). We and others have recently shown that paucity of functional death receptors (DR4/5) on the cell surface of tumor cells is one of the major reasons for drug resistance, but their involvement in the context of in CSCs is poorly understood. By harnessing CSC specific cytotoxic function of salinomycin, we discovered a critical role of epigenetic modulator EZH2 in regulating the expression of DRs in colon CSCs. Our unbiased proteome profiler array approach followed by ChIP analysis of salinomycin treated cells indicated that the expression of DRs, especially DR4 is epigenetically repressed in colon CSCs. Concurrently, EZH2 knockdown demonstrated increased expression of DR4/DR5, significant reduction of CSC phenotype such as spheroid formation in-vitro and tumorigenic potential in-vivo in colon cancer. TCGA data analysis of human colon cancer clinical samples shows strong inverse correlation between EZH2 and DR4. Taken together, this study provides an insight about epigenetic regulation of DR4 in colon CSCs and advocates that drug resistant colon cancer can be therapeutically targeted by combining TRAIL and small molecule EZH2 inhibitors.


2015 ◽  
Vol 29 (S1) ◽  
Author(s):  
Eunju Kim ◽  
Soo Jin Min ◽  
Ji Ye Lim ◽  
Yoo‐Sun Kim ◽  
Kyung‐Mi Kim ◽  
...  

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