MicroRNA-587 antagonizes 5-FU-induced apoptosis and confers drug resistance by regulating PPP2R1B expression in colorectal cancer

Abstract Drug resistance is one of the major hurdles for cancer treatment. However, the underlying mechanisms are still largely unknown and therapeutic options remain limited. In this study, we show that microRNA (miR)-587 confers resistance to 5-fluorouracil (5-FU)-induced apoptosis in vitro and reduces the potency of 5-FU in the inhibition of tumor growth in a mouse xenograft model in vivo. Further studies indicate that miR-587 modulates drug resistance through downregulation of expression of PPP2R1B, a regulatory subunit of the PP2A complex, which negatively regulates AKT activation. Knockdown of PPP2R1B expression increases AKT phosphorylation, which leads to elevated XIAP expression and enhanced 5-FU resistance; whereas rescue of PPP2R1B expression in miR-587-expressing cells decreases AKT phosphorylation/XIAP expression, re-sensitizing colon cancer cells to 5-FU-induced apoptosis. Moreover, a specific and potent AKT inhibitor, MK2206, reverses miR-587-conferred 5-FU resistance. Importantly, studies of colorectal cancer specimens indicate that the expression of miR-587 and PPP2R1B positively and inversely correlates with chemoresistance, respectively, in colorectal cancer. These findings indicate that the miR-587/PPP2R1B/pAKT/XIAP signaling axis has an important role in mediating response to chemotherapy in colorectal cancer. A major implication of our study is that inhibition of miR-587 or restoration of PPP2R1B expression may have significant therapeutic potential to overcome drug resistance in colorectal cancer patients and that the combined use of an AKT inhibitor with 5-FU may increase efficacy in colorectal cancer treatment.

Download Full-text

Oncogenic lncRNA ZNF561-AS1 is essential for colorectal cancer proliferation and survival through regulation of miR-26a-3p/miR-128-5p-SRSF6 axis

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-01882-1 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Zizhen Si ◽

Lei Yu ◽

Haoyu Jing ◽

Lun Wu ◽

Xidi Wang

Keyword(s):

Colorectal Cancer ◽

Rna Binding ◽

Xenograft Model ◽

Luciferase Reporter ◽

Cancer Proliferation ◽

Mouse Xenograft ◽

Mouse Xenograft Model

Abstract Background Long non-coding RNAs (lncRNA) are reported to influence colorectal cancer (CRC) progression. Currently, the functions of the lncRNA ZNF561 antisense RNA 1 (ZNF561-AS1) in CRC are unknown. Methods ZNF561-AS1 and SRSF6 expression in CRC patient samples and CRC cell lines was evaluated through TCGA database analysis, western blot along with real-time PCR. SRSF6 expression in CRC cells was also examined upon ZNF561-AS1 depletion or overexpression. Interaction between miR-26a-3p, miR-128-5p, ZNF561-AS1, and SRSF6 was examined by dual luciferase reporter assay, as well as RNA binding protein immunoprecipitation (RIP) assay. Small interfering RNA (siRNA) mediated knockdown experiments were performed to assess the role of ZNF561-AS1 and SRSF6 in the proliferative actives and apoptosis rate of CRC cells. A mouse xenograft model was employed to assess tumor growth upon ZNF561-AS1 knockdown and SRSF6 rescue. Results We find that ZNF561-AS1 and SRSF6 were upregulated in CRC patient tissues. ZNF561-AS1 expression was reduced in tissues from treated CRC patients but upregulated in CRC tissues from relapsed patients. SRSF6 expression was suppressed and enhanced by ZNF561-AS1 depletion and overexpression, respectively. Mechanistically, ZNF561-AS1 regulated SRSF6 expression by sponging miR-26a-3p and miR-128-5p. ZNF561-AS1-miR-26a-3p/miR-128-5p-SRSF6 axis was required for CRC proliferation and survival. ZNF561-AS1 knockdown suppressed CRC cell proliferation and triggered apoptosis. ZNF561-AS1 depletion suppressed the growth of tumors in a model of a nude mouse xenograft. Similar observations were made upon SRSF6 depletion. SRSF6 overexpression reversed the inhibitory activities of ZNF561-AS1 in vivo, as well as in vitro. Conclusion In summary, we find that ZNF561-AS1 promotes CRC progression via the miR-26a-3p/miR-128-5p-SRSF6 axis. This study reveals new perspectives into the role of ZNF561-AS1 in CRC.

Download Full-text

Transforming Growth Factor β Mediates Drug Resistance by Regulating the Expression of Pyruvate Dehydrogenase Kinase 4 in Colorectal Cancer

Journal of Biological Chemistry ◽

10.1074/jbc.m116.713735 ◽

2016 ◽

Vol 291 (33) ◽

pp. 17405-17416 ◽

Cited By ~ 24

Author(s):

Yang Zhang ◽

Yi Zhang ◽

Liying Geng ◽

Haowei Yi ◽

Wei Huo ◽

...

Keyword(s):

Colorectal Cancer ◽

Colon Cancer ◽

Drug Resistance ◽

Cancer Cells ◽

Pyruvate Dehydrogenase ◽

Pyruvate Dehydrogenase Kinase ◽

Dependent Manner ◽

Colon Cancer Cells ◽

Pyruvate Dehydrogenase Kinase 4 ◽

Mouse Xenograft Model

Drug resistance is one of the main causes of colon cancer recurrence. However, our understanding of the underlying mechanisms and availability of therapeutic options remains limited. Here we show that expression of pyruvate dehydrogenase kinase 4 (PDK4) is positively correlated with drug resistance of colon cancer cells and induced by 5-fluorouracil (5-FU) treatment in drug-resistant but not drug-sensitive cells. Knockdown of PDK4 expression sensitizes colon cancer cells to 5-FU or oxaliplatin-induced apoptosis in vitro and increases the effectiveness of 5-FU in the inhibition of tumor growth in a mouse xenograft model in vivo. In addition, we demonstrate for the first time that TGFβ mediates drug resistance by regulating PDK4 expression and that 5-FU induces PDK4 expression in a TGFβ signaling-dependent manner. Mechanistically, knockdown or inhibition of PDK4 significantly increases the inhibitory effect of 5-FU on expression of the anti-apoptotic factors Bcl-2 and survivin. Importantly, studies of patient samples indicate that expression of PDK4 and phosphorylation of Smad2, an indicator of TGFβ pathway activation, show a strong correlation and that both positively associate with chemoresistance in colorectal cancer. These findings indicate that the TGFβ/PDK4 signaling axis plays an important role in the response of colorectal cancer to chemotherapy. A major implication of our studies is that inhibition of PDK4 may have considerable therapeutic potential to overcome drug resistance in colorectal cancer patients, which warrants the development of PDK4-specific inhibitors.

Download Full-text

GSK3β Inhibition Synergizes with PARP Inhibitors through the Induction of Homologous Recombination Deficiency in Colorectal Cancer

10.21203/rs.3.rs-48785/v1 ◽

2020 ◽

Author(s):

Ning Zhang ◽

Yu-Nan Tian ◽

Li-Na Zhou ◽

Meng-Zhu Li ◽

Shan-Shan Song ◽

...

Keyword(s):

Colorectal Cancer ◽

Homologous Recombination ◽

High Throughput Screening ◽

Glycogen Synthase ◽

Objective Response ◽

Xenograft Model ◽

Parp Inhibitors ◽

High Rate ◽

Parp Inhibition ◽

Mouse Xenograft Model

Abstract Background: Monotherapy with poly ADP-ribose polymerase (PARP) inhibitors results in limited objective response rate (≤ 60% in most cases) in patients with homologous recombination repair (HRR)-deficient cancer, which suggests a high rate of resistance in this subset of patients to PARP inhibitors (PARPi). To overcome resistance to PARPi and to broaden their clinical use, we performed high-throughput screening of 99 anticancer drugs in combination with PARPi to identify potential therapeutic combinations. Methods: The effects of PARPi combined with glycogen synthase kinase 3 (GSK3) inhibitors were investigated in vitro with respect to cell viability, cell cycle and apoptosis. The synergy was assessed by calculation of the combination index (CI). GSK3α null and GSK3β null cells were generated using CRISPR/Cas9 technique. The underlying mechanism was examined by western blotting, flow cytometry, qRT-PCR and fluorescence microscopy. This combination was also evaluated in the mouse xenograft model; tumor growth and tumor lysates were analyzed, and the immunohistochemistry assay was performed. All data are presented as mean ± SD. Comparison between two groups was performed with the Student’s t-test.Result: The data showed that ~25% of oncological drugs and kinase inhibitors that were evaluated displayed synergy with PARPi in HCT-15 cells. Among the tested agents, GSK3 inhibitors (GSK3i) exhibited the strongest synergistic effect with PARPi. Moreover, the synergistic antitumor effect of GSK3 and PARP inhibition was confirmed in a panel of colorectal cancer (CRC) cell lines with diverse genetic backgrounds. Additionally, inhibition or genetic depletion of GSK3β was found to impair HRR of DNA and reduce the mRNA and protein level of BRCA1. Finally, we demonstrated that inhibition or depletion of GSK3β could enhance the in vivo sensitivity to simmiparib without toxicity.Conclusion: Our results provide a mechanistic understanding of combination of PARP and GSK3 inhibition, and support the clinical development of this combination therapy for CRC patients.

Download Full-text

New mouse xenograft model modulated by tumor-associated fibroblasts for human multi-drug resistance in cancer

Oncology Reports ◽

10.3892/or.2015.4265 ◽

2015 ◽

Vol 34 (5) ◽

pp. 2699-2705 ◽

Cited By ~ 5

Author(s):

YAN MA ◽

ZHIQIANG LIN ◽

JOHN K. FALLON ◽

QIANG ZHAO ◽

DAN LIU ◽

...

Keyword(s):

Drug Resistance ◽

Xenograft Model ◽

Multi Drug Resistance ◽

Mouse Xenograft ◽

Mouse Xenograft Model

Download Full-text

Aptamer-mediated survivin RNAi enables 5-fluorouracil to eliminate colorectal cancer stem cells

Scientific Reports ◽

10.1038/s41598-017-05859-z ◽

2017 ◽

Vol 7 (1) ◽

Cited By ~ 23

Author(s):

Hadi AlShamaileh ◽

Tao Wang ◽

Dongxi Xiang ◽

Wang Yin ◽

Phuong Ha-Lien Tran ◽

...

Keyword(s):

Colorectal Cancer ◽

Stem Cells ◽

Cancer Stem Cells ◽

Xenograft Model ◽

Chemotherapeutic Agents ◽

Mouse Xenograft Model ◽

Colorectal Cancer Cells ◽

Colorectal Cancer Stem Cells ◽

Molecular Therapeutic

AbstractThe development of chemoresistance and inability in elimination of cancer stem cells are among the key limitations of cancer chemotherapy. Novel molecular therapeutic strategies able to overcome such limitations are urgently needed for future effective management of cancer. In this report, we show that EpCAM-aptamer-guided survivin RNAi effectively downregulated survivin both in colorectal cancer cells in vitro and in a mouse xenograft model for colorectal cancer. When combined with the conventional chemotherapeutic agents, the aptamer-guided survivin RNAi was able to enhance the sensitivity towards 5-FU or oxaliplatin in colorectal cancer stem cells, increase apoptosis, inhibit tumour growth and improve the overall survival of mice bearing xenograft colorectal cancer. Our results indicate that survivin is one of the key players responsible for the innate chemoresistance of colorectal cancer stem cells. Thus, aptamer-mediated targeting of survivin in cancer stem cells in combination with chemotherapeutic drugs constitutes a new avenue to improve treatment outcome in oncologic clinics.

Download Full-text

Anlotinib Overcomes Multiple Drug Resistant Colorectal Cancer Cells via Inactivating PI3K/AKT Pathway

Anti-Cancer Agents in Medicinal Chemistry ◽

10.2174/1871520621666210112113852 ◽

2021 ◽

Vol 21 ◽

Author(s):

Weilan Lan ◽

Jinyan Zhao ◽

Wujin Chen ◽

Haixia Shang ◽

Jun Peng ◽

...

Keyword(s):

Colorectal Cancer ◽

Drug Resistance ◽

Cell Viability ◽

Cancer Cells ◽

Cell Apoptosis ◽

Caspase 3 ◽

Akt Pathway ◽

Inhibition Of Proliferation ◽

Colorectal Cancer Cells ◽

Induced Apoptosis

Background: Anlotinib is a multi-target tyrosine kinase inhibitor that has been reported to have activity against colorectal cancer. However, the mechanisms of how anlotinib mediates drug-resistance of colorectal cancer have not been fully described. Particularly the potential mechanisms regarding to the inhibition of proliferation and induction of apoptosis remain unknown. Objective: In this study, we intended to study the effect and related-mechanism of the proliferation, migration, invasion and induced apoptosis of anlotinib overcoming multidrug resistant colorectal cancer cells through in vitro experiments. Methods: Cell viability was determined by MTT assays and the resistant index was calculated. Colony formation and PI/RNase Staining were used for testing the proliferation of resistant cells. DAPI staining and Annexin V-FITC/PI staining were used to detect cell apoptosis. Migration and invasion were examined by transwell. Protein expression and activation of PI3K/AKT pathway were detected by western blot. LY294002 was used to verify whether anlotinib overcomes the drug-resistance of CRC cells by inactivating the PI3K/AKT pathway. Results: The results showed that the HCT-8/5-FU cells were resistant to multiple chemotherapy drugs (5-FU, ADM and DDP). Anlotinib significantly inhibited the cell viability, proliferation, migration, invasion and induced the cell apoptosis. Moreover, anlotinib downregulated the expression of survivin, cyclin D1, CDK4, caspase-3, Bcl-2, MMP-2, MMP-9, vimentin and N-cadherin, but up-regulated cleaved-caspase-3, Bax and E-cadherin and blocked the activity of the PI3K/AKT in HCT-8/5-FU cells. We found anlotinib and LY294002 overcame the drug resistance of HCT-8/5-FU cells by reducing the expression of PI3K/p-AKT. Conclusions: Anlotinib inhibited the proliferation, migration, invasion and induced apoptosis of HCT-8/5-FU cells, and the mechanisms may be that anlotinib conquered multidrug resistance of colorectal cancer cells via inactivating of PI3K/AKT pathway.

Download Full-text

O7 A bispecific VHH approach to leverage the potent and widely applicable tumor cytolytic capacity of Vγ9Vδ2 T cells

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-itoc7.12 ◽

2020 ◽

Vol 8 (Suppl 2) ◽

pp. A6.2-A7

Author(s):

LA King ◽

R Lameris ◽

RC Roovers ◽

P Parren ◽

TD de Gruijl ◽

...

Keyword(s):

Colorectal Cancer ◽

T Cells ◽

T Cell ◽

Xenograft Model ◽

Cell Receptor ◽

Target Cells ◽

Mouse Xenograft Model ◽

Vγ9vδ2 T Cells

Vγ9Vδ2-T cells include a unique and potent subset of T cells which play an important role in tumor defense. Vγ9Vδ2-T cells recognize and can lyse butyrophilin 3A1-expressing target cells with elevated levels of non-peptide phosphoantigens (pAg), induced by cell stress or malignancy. To date, Vγ9Vδ2-T cell based cancer immunotherapeutic approaches were well tolerated and in some cases capable of inducing relevant clinical responses. In an effort to improve the efficacy and consistency of Vγ9Vδ2-T cell based cancer immunotherapy, we designed a bispecific VHH that binds to both Vγ9Vδ2-T cells and EGFR expressed by tumor cells and results in the target-specific activation of Vγ9Vδ2-T cells and subsequent lysis of colorectal cancer cell lines and primary colorectal cancer samples both in vitro and in an in vivo mouse xenograft model. Of note, tumor cell lysis was independent of mutations in KRAS and BRAF that are known to impair the efficacy of clinically registered anti-EGFR monoclonal antibodies as well as common Vγ9Vδ2-T cell receptor sequence variations. In combination with the conserved monomorphic nature of the Vγ9Vδ2-TCR and the facile replacement of the tumor-specific VHH, this immunotherapeutic approach can in principle be applied to a large group of cancer types.Disclosure InformationL.A. King: None. R. Lameris: None. R.C. Roovers: None. P. Parren: None. T.D. de Gruijl: None. H.J. van der Vliet: None.

Download Full-text