CHK1 inhibitor sensitizes resistant colorectal cancer stem cells to nortopsentin.
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ABSTRACT:
SUBMITTER: Di Franco S
PROVIDER: S-EPMC8209271 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Cancer stem cells (CSCs) drive not only tumor initiation and expansion, but also therapeutic resistance and tumor relapse. Therefore, CSC eradication is required for effective cancer therapy. In preclinical models, CSCs demonstrated high capability to tolerate even extensive genotoxic stress, including replication stress, because they are endowed with a very robust DNA damage response (DDR). This favors the survival of DNA-damaged CSCs instead of their inhibition via apoptosis or senescence. The DDR represents a unique CSC vulnerability, but the abrogation of the DDR through the inhibition of the ATR-CHK1 axis is effective only against some subtypes of CSCs, and resistance often emerges. Here, we analyzed the impact of druggable DDR players in the response of patient-derived colorectal CSCs (CRC-SCs) to CHK1/2 inhibitor prexasertib, identifying RAD51 and MRE11 as sensitizing targets enhancing prexasertib efficacy. We showed that combined inhibition of RAD51 and CHK1 (via B02+prexasertib) or MRE11 and CHK1 (via mirin+prexasertib) kills CSCs by affecting multiple genoprotective processes. In more detail, these two prexasertib-based regimens promote CSC eradication through a sequential mechanism involving the induction of elevated replication stress in a context in which cell cycle checkpoints usually activated during the replication stress response are abrogated. This leads to uncontrolled proliferation and premature entry into mitosis of replication-stressed cells, followed by the induction of mitotic catastrophe. CRC-SCs subjected to RAD51+CHK1 inhibitors or MRE11+CHK1 inhibitors are eventually eliminated, and CRC-SC tumorspheres inhibited or disaggregated, via a caspase-dependent apoptosis. These results support further clinical development of these prexasertib-based regimens in colorectal cancer patients.
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Project description:Ewing sarcoma is a bone and soft tissue sarcoma that occurs in children and young adults. The EWS-FLI1 gene fusion is the driver mutation in most Ewing sarcoma tumors and functions, in part, as an aberrant transcription factor. We recently identified that Ewing sarcoma cells are sensitive to inhibition of ribonucleotide reductase (RNR), which catalyzes the formation of deoxyribonucleotides from ribonucleotides. In this report, we show that Ewing sarcoma cells are sensitive to treatment with clofarabine, which is a nucleoside analogue and allosteric inhibitor of RNR. However, clofarabine is a reversible inhibitor of RNR and we found that the effect of clofarabine is limited when using a short (6-hour) drug treatment. Gemcitabine, on the other hand, is an irreversible inhibitor of the RRM1 subunit of RNR and this drug induces apoptosis in Ewing sarcoma cells when used in both 6-hour and longer drug treatments. Treatment of Ewing sarcoma cells with gemcitabine also results in activation of checkpoint kinase 1 (CHK1), which is a critical mediator of cell survival in the setting of impaired DNA replication. Notably, inhibition of CHK1 function in Ewing sarcoma cells using a small-molecule CHK1 inhibitor, or siRNA knockdown, in combination with gemcitabine results in increased toxicity both in vitro and in vivo in a mouse xenograft experiment. Overall, our results provide insight into Ewing sarcoma biology and identify a candidate therapeutic target, and drug combination, in Ewing sarcoma.
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Project description:Checkpoint kinase 1 (CHK1) plays a key role in genome surveillance and integrity throughout the cell cycle. Selective inhibitors of CHK1 (CHK1i) are undergoing clinical evaluation for various human malignancies, including neuroblastoma. In this study, one CHK1i-sensitive neuroblastoma cell line, CHP134, was investigated, which characteristically carries MYCN amplification and a chromosome deletion within the 10q region. Among several cancer-related genes in the chromosome 10q region, mRNA expression of fibroblast growth factor receptor 2 (FGFR2) was altered in CHP134 cells and associated with an unfavorable prognosis of patients with neuroblastoma. Induced expression of FGFR2 in CHP134 cells reactivated downstream MEK/ERK signaling and resulted in cells resistant to CHK1i-mediated cell growth inhibition. Consistently, the MEK1/2 inhibitor, trametinib, potentiated CHK1 inhibitor-mediated cell death in these cells. These results suggested that FGFR2 loss might be prone to highly effective CHK1i treatment. In conclusion, extreme cellular dependency of ERK activation may imply a possible application for the MEK1/2 inhibitor, either as a single inhibitor or in combination with CHK1i in MYCN-amplified neuroblastomas.
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Project description:Proteasome inhibitors, such as bortezomib and carfilzomib, are FDA approved for the treatment of hemopoietic cancers, but recent studies have shown their great potential for treatment of solid tumors. Bax?2, a unique proapoptotic Bax isoform, promotes non-mitochondrial cell death and sensitizes cancer cells to chemotherapy. However, endogenous Bax?2 proteins are unstable and susceptible to proteasomal degradation. Here, we screened a panel of proteasome inhibitors in colorectal cancer cells with different Bax statuses. We found that all proteasome inhibitors tested were able to block Bax?2 degradation without affecting the level of Bax? or Bcl-2 proteins. Among the inhibitors tested, only bortezomib and carfilzomib were able to induce differential cell death corresponding to the distinct Bax statuses. Bax?2-positive cells had a significantly higher level of cell death at low nanomolar concentrations than Bax?-positive or Bax-negative cells. Furthermore, bortezomib-induced cell death in Bax?2-positive cells was predominantly dependent on the caspase 8/3 pathway, consistent with our previous studies. These results imply that Bax?2 can selectively sensitize cancer cells to proteasome inhibitors, enhancing their potential to treat colon cancer and other solid tumors.
| S-EPMC6022363 | biostudies-literature
Project description:BRAF mutant colorectal cancer has a poor prognosis and gets resistant to BRAF inhibitors quickly. This study aims to clarify the mechanism of resistance to BRAFi. We found MCU1-C is overexpressed in BRAF mutant colorectal cancer and targeting MUC1-C genetically and pharmacologically sensitized Colorectal cancer cells to BRAF inhibitor. This finding suggests that MUC1-C could be a new therapeutic target for BRAF mutant colorectal cancer.
2022-11-30 | GSE215849 | GEO
Project description:BACKGROUND:Glioblastoma is the most common and aggressive brain tumour in adults with a median overall survival of only 14?months after standard therapy with radiation therapy (IR) and temozolomide (TMZ). In a novel multimodal treatment approach we combined the checkpoint kinase 1 (Chk1) inhibitor SAR-020106 (SAR), disrupting homologue recombination, with standard DNA damage inducers (IR, TMZ) and the epigenetic/cytotoxic drug decitabine (5-aza-2'-deoxycitidine, 5-aza-dC). Different in vitro glioblastoma models are monitored to evaluate if the impaired DNA damage repair may chemo/radiosensitize the tumour cells. METHODS:Human p53-mutated (p53-mut) and -wildtype (p53-wt) glioblastoma cell lines (p53-mut: LN405, T98G; p53-wt: A172, DBTRG) and primary glioblastoma cells (p53-mut: P0297; p53-wt: P0306) were treated with SAR combined with TMZ, 5-aza-dC, and/or IR and analysed for induction of apoptosis (AnnexinV and sub-G1 assay), cell cycle distribution (nuclear PI staining), DNA damage (alkaline comet or gH2A.X assay), proliferation inhibition (BrdU assay), reproductive survival (clonogenic assay), and potential tumour stem cells (nestinpos/GFAPneg fluorescence staining). Potential treatment-induced neurotoxicity was evaluated on nestin-positive neural progenitor cells in a murine entorhinal-hippocampal slice culture model. RESULTS:SAR showed radiosensitizing effects on the induction of apoptosis and on the reduction of long-term survival in p53-mut and p53-wt glioblastoma cell lines and primary cells. In p53-mut cells, this effect was accompanied by an abrogation of the IR-induced G2/M arrest and an enhancement of IR-induced DNA damage by SAR treatment. Also TMZ and 5-aza-dC acted radioadditively albeit to a lesser extent. The multimodal treatment achieved the most effective reduction of clonogenicity in all tested cell lines and did not affect the ratio of nestinpos/GFAPneg cells. No neurotoxic effects were detected when the number of nestin-positive neural progenitor cells remained unchanged after multimodal treatment. CONCLUSION:The Chk1 inhibitor SAR-020106 is a potent sensitizer for DNA damage-induced cell death in glioblastoma therapy strongly reducing clonogenicity of tumour cells. Selectively enhanced p53-mut cell death may provide stronger responses in tumours defective of non-homologous end joining (NHEJ). Our results suggest that a multimodal therapy involving DNA damage inducers and DNA repair inhibitors might be an effective anti-tumour strategy with a low risk of neurotoxicity.
| S-EPMC6805470 | biostudies-literature
Project description:PURPOSE:Chk1 inhibition increases cell sensitivity to both chemotherapy and radiotherapy in several tumour types and is, therefore, a promising anti-cancer approach. Although several Chk1 inhibitors have been developed, their clinical progress has been hampered by low bioavailability and off-target toxicities. MATERIALS AND METHODS:We characterized the radiosensitizing activity of CCT244747, the first orally bioavailable Chk1 inhibitor. We used a panel of bladder and head and neck cancer cell lines and monitored the effect of combining CCT244747 with radiation both in in vitro and in vivo models. RESULTS:CCT244747 sensitized cancer cell lines to radiation in vitro and resulted in a growth delay in cancer xenograft models associated with a survival benefit. Radiosensitization was elicited by abrogation of the radiation-induced G2 arrest and premature entry into mitosis. CONCLUSIONS:CCT244747 is a potent and specific Chk1 inhibitor that can be administered orally. It radiosensitizes tumour cell lines and represents a new therapy for clinical application in combination with radiotherapy.
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Project description:Rituximab efficacy in cancer therapy depends in part on induction of complement-dependent cytotoxicity (CDC). Human CD59 (hCD59) is a key complement regulatory protein that restricts the formation of the membrane attack complex, thereby inhibiting induction of CDC. hCD59 is highly expressed in B-cell non-Hodgkin's lymphoma (NHL), and upregulation of hCD59 is an important determinant of the sensitivity of NHL cells to rituximab treatment. Here, we report that the potent hCD59 inhibitor rILYd4 enhances CDC in vitro and in vivo, thereby sensitizing rituximab-resistant lymphoma cells and primary chronic lymphocytic leukemia cells (CLL) to rituximab treatment. By defining pharmcokinetic/pharmacodynamic profiles of rILYd4 in mice, we showed that by itself rILYd4 does not adversely mediate in vivo hemolysis of hCD59-expressing erythrocytes. Increasing expression levels of the complement regulators CD59 and CD55 in rituximab-resistant cells occur due to selection of preexisting clones rather than de novo induction of these proteins. Moreover, lymphoma cells overexpressing CD59 were directly responsible for the resistance to rituximab-mediated CDC therapy. Our results rationalize the use of rILYd4 as a therapeutic adjuvant for rituximab treatment of rituximab-resistant lymphoma and CLL. Furthermore, they suggest that preemptive elimination of CD59-overexpressing subpopulations along with rituximab treatment may be a useful approach to ablate or conquer rituximab resistance.
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Project description:The molecule DRO1 (down‑regulated by oncogenes 1) is a potential tumor suppressor protein that is frequently down‑regulated in primary colorectal cancers and colorectal cancer cell lines. Although the mechanism of DRO1 action has yet to be elucidated, previous data have suggested that DRO1 interferes with tumor growth by sensitizing cells to apoptosis. The effect of DRO1 expression on receptor-, mitochondrial- and endoplasmic reticulum‑mediated apoptosis in colorectal cancer cell lines was analyzed in this study, following the generation of DLD1/DRO1 and HCT116/DRO1 cell lines. Cells were cultured, and then analyzed using flow cytometry. DRO1 was found to sensitize cells to receptor-mediated apoptosis by promoting the activation of components of the death-inducing signaling complex (DISC).
| S-EPMC3408059 | biostudies-literature
Project description:CONTEXTMultiple drug resistance is the major obstacle to conventional chemotherapy. Silibinin, a nontoxic naturally occurring compound, has anticancer activity and can increase the cytotoxic effects of chemotherapy in various cancer models.OBJECTIVETo evaluate the effects of silibinin on enhancing the sensitivity of chemo-resistant human breast cell lines to doxorubicin (DOX) and paclitaxel (PAC).MATERIALS AND METHODSThe cells were treated with silibinin (at 50 to 600??M concentrations) and/or chemo drugs for 24 and 48?h, then cell viability and changes in oncogenic proteins were determined by MTT assay and Western blotting/RT-PCR, respectively. Flow cytometry was used to study apoptosis in the cells receiving different treatments. The antitumorigenic effects of silibinin (at 200 to 400??M concentration) were evaluated by mammosphere assay.RESULTSSilibinin exerted significant growth inhibitory effects with IC50 ranging from 200 to 570??M in different cell lines. Treatment of DOX-resistant MDA-MB-435 cells with silibinin at 200??M reduced DOX IC50 from 71 to 10??g/mL and significantly suppressed the key oncogenic pathways including STAT3, AKT, and ERK in these cells. Interestingly treatment of DOX-resistant MDA-MB-435 cells with silibinin at 400??M concentration for 48?h induced a 50% decrease in the numbers of colonies as compared with DMSO-treated cells. Treatment of PAC-resistant MCF-7 cells with silibinin at 400??M concentration generated synergistic effects when it was used in combination with PAC at 250?nM concentration (CI?=?0.81).CONCLUSIONSilibinin sensitizes chemo-resistant cells to chemotherapeutic agents and can be useful in treating breast cancers.
| S-EPMC6130726 | biostudies-literature