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JNK is required for maintaining the tumor-initiating cell-like properties of acquired chemoresistant human cancer cells.

Liu Y, Zhang X, Wang J, Yang J, Tan WF - Acta Pharmacol. Sin. (2015)

Bottom Line: Additionally, inhibition of JNK activity significantly inhibited the in vitro and in vivo tumor-initiating abilities of KB/VCR cells.Furthermore, our data suggest that blocking JNK activity abundantly inhibited the Hedgehog (Hh) pathway activity, as reflected by reduction of Hedgehog (Hh) pathway target genes Gli1 and ptch1 at the mRNA level as well as Gli-luciferase activity.Thus, disruption of tumor-initiating cell-like properties by targeting JNK may be a new approach to combating acquired chemoresistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China.

ABSTRACT

Aim: Many studies reveal an association between the acquired chemoresistant phenotype of cancer cells and tumor-initiating cell-like properties. The aim of this study was to determine the impact of c-Jun N-terminal kinase (JNK) on the tumor-initiating cell-like properties of acquired chemoresistant human cancer cells.

Methods: Two well-established human acquired chemoresistant cancer cell lines K562/A02 and KB/VCR, as well as their respective parental counterparts K562 and KB were tested. The expression of relevant mRNAs and proteins was detected using qRT-PCR and Western blotting, respectively. Sphere formation and self-renewal assays were used to study the tumor-initiating cell-like properties. Soft agar and colony formation assays were used to investigate tumorigenic ability.

Results: We observed that suppressing JNK activity by its specific small molecule inhibitor SP600125 or by limiting JNK1/2 expression with JNK1/2 shRNA lentiviruses inhibited the expression of pluripotent stem cell markers such as Oct4, Sox2, and Nanog in KB/VCR cells and K562/A02 cells as well as sphere formation and self-renewal abilities of K562/A02 cells. Additionally, inhibition of JNK activity significantly inhibited the in vitro and in vivo tumor-initiating abilities of KB/VCR cells. Furthermore, our data suggest that blocking JNK activity abundantly inhibited the Hedgehog (Hh) pathway activity, as reflected by reduction of Hedgehog (Hh) pathway target genes Gli1 and ptch1 at the mRNA level as well as Gli-luciferase activity.

Conclusion: JNK maintains the tumor-initiating cell-like properties of acquired chemoresistant K562/A02 and KB/VCR cells potentially through activating the Hedgehog pathway. Thus, disruption of tumor-initiating cell-like properties by targeting JNK may be a new approach to combating acquired chemoresistance.

No MeSH data available.


Related in: MedlinePlus

Blocking JNK activity inhibited the in vivo tumor-initiating ability of acquired chemoresistant cancer cells. (A) Expression of phosphorylated c-Jun, Flag, and GFP in KB/VCR cells after infection with GFP or JNK DM lentiviruses. (B) Tumor formation of KB or KB/VCR cells after infection with lentiviruses harboring GFP, JNK DM, or JNK1/2 shRNA. Mean±SD. n=3. bP<0.05.
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fig4: Blocking JNK activity inhibited the in vivo tumor-initiating ability of acquired chemoresistant cancer cells. (A) Expression of phosphorylated c-Jun, Flag, and GFP in KB/VCR cells after infection with GFP or JNK DM lentiviruses. (B) Tumor formation of KB or KB/VCR cells after infection with lentiviruses harboring GFP, JNK DM, or JNK1/2 shRNA. Mean±SD. n=3. bP<0.05.

Mentions: To test the effect of blocking JNK activity on the in vivo tumorigenic ability of acquired chemoresistant cancer cells, we infected KB/VCR cells with lentiviruses harboring JNK1(APF), a dominant negative mutant of JNK (JNK DM)18. Inhibition of c-Jun phosphorylation served as inhibition efficiency of JNK DM (Figure 4A); GFP or Flag immunoblots were used as a readout of GFP or JNK DM expression (Figure 4A). We xenografted subcutaneously KB/VCR cells (2×103) that had been infected with lentiviruses harboring GFP or JNK DM into nude mice. The result demonstrated that KB/VCR cells infected with lentiviruses harboring GFP formed 8 tumors of 12 injections, whereas only one and two tumors were generated by KB/VCR cells that had been infected with lentiviruses harboring JNK DM and JNK1/2 shRNA, respectively (Figure 4B), suggesting that blocking JNK activity may inhibit the in vivo tumorigenic ability of acquired chemoresistant cancer cells.


JNK is required for maintaining the tumor-initiating cell-like properties of acquired chemoresistant human cancer cells.

Liu Y, Zhang X, Wang J, Yang J, Tan WF - Acta Pharmacol. Sin. (2015)

Blocking JNK activity inhibited the in vivo tumor-initiating ability of acquired chemoresistant cancer cells. (A) Expression of phosphorylated c-Jun, Flag, and GFP in KB/VCR cells after infection with GFP or JNK DM lentiviruses. (B) Tumor formation of KB or KB/VCR cells after infection with lentiviruses harboring GFP, JNK DM, or JNK1/2 shRNA. Mean±SD. n=3. bP<0.05.
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Related In: Results  -  Collection

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fig4: Blocking JNK activity inhibited the in vivo tumor-initiating ability of acquired chemoresistant cancer cells. (A) Expression of phosphorylated c-Jun, Flag, and GFP in KB/VCR cells after infection with GFP or JNK DM lentiviruses. (B) Tumor formation of KB or KB/VCR cells after infection with lentiviruses harboring GFP, JNK DM, or JNK1/2 shRNA. Mean±SD. n=3. bP<0.05.
Mentions: To test the effect of blocking JNK activity on the in vivo tumorigenic ability of acquired chemoresistant cancer cells, we infected KB/VCR cells with lentiviruses harboring JNK1(APF), a dominant negative mutant of JNK (JNK DM)18. Inhibition of c-Jun phosphorylation served as inhibition efficiency of JNK DM (Figure 4A); GFP or Flag immunoblots were used as a readout of GFP or JNK DM expression (Figure 4A). We xenografted subcutaneously KB/VCR cells (2×103) that had been infected with lentiviruses harboring GFP or JNK DM into nude mice. The result demonstrated that KB/VCR cells infected with lentiviruses harboring GFP formed 8 tumors of 12 injections, whereas only one and two tumors were generated by KB/VCR cells that had been infected with lentiviruses harboring JNK DM and JNK1/2 shRNA, respectively (Figure 4B), suggesting that blocking JNK activity may inhibit the in vivo tumorigenic ability of acquired chemoresistant cancer cells.

Bottom Line: Additionally, inhibition of JNK activity significantly inhibited the in vitro and in vivo tumor-initiating abilities of KB/VCR cells.Furthermore, our data suggest that blocking JNK activity abundantly inhibited the Hedgehog (Hh) pathway activity, as reflected by reduction of Hedgehog (Hh) pathway target genes Gli1 and ptch1 at the mRNA level as well as Gli-luciferase activity.Thus, disruption of tumor-initiating cell-like properties by targeting JNK may be a new approach to combating acquired chemoresistance.

View Article: PubMed Central - PubMed

Affiliation: Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai 201203, China.

ABSTRACT

Aim: Many studies reveal an association between the acquired chemoresistant phenotype of cancer cells and tumor-initiating cell-like properties. The aim of this study was to determine the impact of c-Jun N-terminal kinase (JNK) on the tumor-initiating cell-like properties of acquired chemoresistant human cancer cells.

Methods: Two well-established human acquired chemoresistant cancer cell lines K562/A02 and KB/VCR, as well as their respective parental counterparts K562 and KB were tested. The expression of relevant mRNAs and proteins was detected using qRT-PCR and Western blotting, respectively. Sphere formation and self-renewal assays were used to study the tumor-initiating cell-like properties. Soft agar and colony formation assays were used to investigate tumorigenic ability.

Results: We observed that suppressing JNK activity by its specific small molecule inhibitor SP600125 or by limiting JNK1/2 expression with JNK1/2 shRNA lentiviruses inhibited the expression of pluripotent stem cell markers such as Oct4, Sox2, and Nanog in KB/VCR cells and K562/A02 cells as well as sphere formation and self-renewal abilities of K562/A02 cells. Additionally, inhibition of JNK activity significantly inhibited the in vitro and in vivo tumor-initiating abilities of KB/VCR cells. Furthermore, our data suggest that blocking JNK activity abundantly inhibited the Hedgehog (Hh) pathway activity, as reflected by reduction of Hedgehog (Hh) pathway target genes Gli1 and ptch1 at the mRNA level as well as Gli-luciferase activity.

Conclusion: JNK maintains the tumor-initiating cell-like properties of acquired chemoresistant K562/A02 and KB/VCR cells potentially through activating the Hedgehog pathway. Thus, disruption of tumor-initiating cell-like properties by targeting JNK may be a new approach to combating acquired chemoresistance.

No MeSH data available.


Related in: MedlinePlus