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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 vitro tumor-initiating ability of KB/VCR cells. (A) Colony formation of KB and KB/VCR cells that were treated with or without SP600125. (B) Colony formation of KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. (C) Anchorage-independent colony formation in KB and KB/VCR cells after treatment with or without SP600125. (D) Anchorage-independent colony formation in KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses.
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fig3: Blocking JNK activity inhibited the in vitro tumor-initiating ability of KB/VCR cells. (A) Colony formation of KB and KB/VCR cells that were treated with or without SP600125. (B) Colony formation of KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. (C) Anchorage-independent colony formation in KB and KB/VCR cells after treatment with or without SP600125. (D) Anchorage-independent colony formation in KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses.

Mentions: To determine whether blocking JNK activity may inhibit the tumorigenic ability of acquired chemoresistant cancer cells, we used a soft agar assay and a colony assay, which are two widely used in vitro tumorigenic assays17. Colony formation assays revealed that KB/VCR cells formed many more colonies than the counterpart KB cells. Treatment with SP600125 clearly reduced the number of colonies formed in KB/VCR cells, while SP600125 had little effect on the colony formation ability of KB cells (Figure 3A). We observed that JNK1/2 knockdown also suppressed the colony formation ability of KB/VCR cells (Figure 3B). Furthermore, colonies formed by KB/VCR cells in an anchorage-independent situation were also suppressed by SP600125 exposure, while SP600125 treatment exhibited no effect on KB cell colony formation in the anchorage-independent situation (Figure 3C). We further confirmed this observation by limiting JNK1/2 expression with JNK1/2 shRNA lentivirus in KB/VCR cells (Figure 3D). Hence, these observations suggest that blocking JNK activity may inhibit the in vitro 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 vitro tumor-initiating ability of KB/VCR cells. (A) Colony formation of KB and KB/VCR cells that were treated with or without SP600125. (B) Colony formation of KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. (C) Anchorage-independent colony formation in KB and KB/VCR cells after treatment with or without SP600125. (D) Anchorage-independent colony formation in KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4561974&req=5

fig3: Blocking JNK activity inhibited the in vitro tumor-initiating ability of KB/VCR cells. (A) Colony formation of KB and KB/VCR cells that were treated with or without SP600125. (B) Colony formation of KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. (C) Anchorage-independent colony formation in KB and KB/VCR cells after treatment with or without SP600125. (D) Anchorage-independent colony formation in KB and KB/VCR cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses.
Mentions: To determine whether blocking JNK activity may inhibit the tumorigenic ability of acquired chemoresistant cancer cells, we used a soft agar assay and a colony assay, which are two widely used in vitro tumorigenic assays17. Colony formation assays revealed that KB/VCR cells formed many more colonies than the counterpart KB cells. Treatment with SP600125 clearly reduced the number of colonies formed in KB/VCR cells, while SP600125 had little effect on the colony formation ability of KB cells (Figure 3A). We observed that JNK1/2 knockdown also suppressed the colony formation ability of KB/VCR cells (Figure 3B). Furthermore, colonies formed by KB/VCR cells in an anchorage-independent situation were also suppressed by SP600125 exposure, while SP600125 treatment exhibited no effect on KB cell colony formation in the anchorage-independent situation (Figure 3C). We further confirmed this observation by limiting JNK1/2 expression with JNK1/2 shRNA lentivirus in KB/VCR cells (Figure 3D). Hence, these observations suggest that blocking JNK activity may inhibit the in vitro 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