Limits...
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

Inhibition of JNK activity suppressed the sphere formation ability and self-renewal capacity of acquired chemoresistant cancer cells. (A) JNK, p-c-Jun, and GFP immunoblots of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. GAPDH was used as a loading control. Sphere formation (B) and self-renewal ability (D) of K562/A02 cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. Sphere formation (C) and self-renewal ability (E) of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. Exposure of SP600125 inhibited sphere formation (F) and the self-renewal abilities (G) of K562/A02 cells. Mean±SD. n=3. bP<0.05, cP<O.01.
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4561974&req=5

fig2: Inhibition of JNK activity suppressed the sphere formation ability and self-renewal capacity of acquired chemoresistant cancer cells. (A) JNK, p-c-Jun, and GFP immunoblots of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. GAPDH was used as a loading control. Sphere formation (B) and self-renewal ability (D) of K562/A02 cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. Sphere formation (C) and self-renewal ability (E) of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. Exposure of SP600125 inhibited sphere formation (F) and the self-renewal abilities (G) of K562/A02 cells. Mean±SD. n=3. bP<0.05, cP<O.01.

Mentions: Sphere formation and self-renewal abilities are two critical tumor-initiating cell-like properties15,16. We observed that limiting JNK1/2 expression in K562/A02 cells (Figure 1E) and KB/VCR cells (Figure 2A) significantly inhibited sphere formation in K562/A02 cells (Figure 2B) and KB/VCR cells (Figure 2C), as reflected by fewer cellular clusters formed compared with controls, suggesting that JNK1/2 is essential for maintaining the sphere formation ability of acquired chemoresistant cancer cells. We further dissociated the cellular clusters formed by K562/A02 cells or KB/VCR cells into single cells for measuring self-renewal capability, an ability of cancer stem cells to refresh stem cells with identical, intact potential for proliferation, expansion, and differentiation, thus maintaining the cancer stem cell pool. We determined that knocking down JNK expression significantly reduced the numbers of cellular clusters that were formed by cells dissociated from the first generation of K562/A02 (Figure 2D) or KB/VCR (Figure 2E) spheres, indicating an inhibition of the self-renewal ability of acquired chemoresistant cancer cells by blocking JNK activity. The impact of JNK1/2 shRNA on sphere formation and self-renewal ability was well recapitulated by SP600125, the small molecular inhibitor of JNK, in K562/A02 cells (Figure 2F, 2G).


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)

Inhibition of JNK activity suppressed the sphere formation ability and self-renewal capacity of acquired chemoresistant cancer cells. (A) JNK, p-c-Jun, and GFP immunoblots of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. GAPDH was used as a loading control. Sphere formation (B) and self-renewal ability (D) of K562/A02 cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. Sphere formation (C) and self-renewal ability (E) of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. Exposure of SP600125 inhibited sphere formation (F) and the self-renewal abilities (G) of K562/A02 cells. Mean±SD. n=3. bP<0.05, cP<O.01.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4561974&req=5

fig2: Inhibition of JNK activity suppressed the sphere formation ability and self-renewal capacity of acquired chemoresistant cancer cells. (A) JNK, p-c-Jun, and GFP immunoblots of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. GAPDH was used as a loading control. Sphere formation (B) and self-renewal ability (D) of K562/A02 cells that were infected with shRNA control or JNK1/2 shRNA lentiviruses. Sphere formation (C) and self-renewal ability (E) of KB/VCR cells that had been infected with shRNA control or JNK1/2 shRNA lentiviruses. Exposure of SP600125 inhibited sphere formation (F) and the self-renewal abilities (G) of K562/A02 cells. Mean±SD. n=3. bP<0.05, cP<O.01.
Mentions: Sphere formation and self-renewal abilities are two critical tumor-initiating cell-like properties15,16. We observed that limiting JNK1/2 expression in K562/A02 cells (Figure 1E) and KB/VCR cells (Figure 2A) significantly inhibited sphere formation in K562/A02 cells (Figure 2B) and KB/VCR cells (Figure 2C), as reflected by fewer cellular clusters formed compared with controls, suggesting that JNK1/2 is essential for maintaining the sphere formation ability of acquired chemoresistant cancer cells. We further dissociated the cellular clusters formed by K562/A02 cells or KB/VCR cells into single cells for measuring self-renewal capability, an ability of cancer stem cells to refresh stem cells with identical, intact potential for proliferation, expansion, and differentiation, thus maintaining the cancer stem cell pool. We determined that knocking down JNK expression significantly reduced the numbers of cellular clusters that were formed by cells dissociated from the first generation of K562/A02 (Figure 2D) or KB/VCR (Figure 2E) spheres, indicating an inhibition of the self-renewal ability of acquired chemoresistant cancer cells by blocking JNK activity. The impact of JNK1/2 shRNA on sphere formation and self-renewal ability was well recapitulated by SP600125, the small molecular inhibitor of JNK, in K562/A02 cells (Figure 2F, 2G).

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