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Selective small molecule Stat3 inhibitor reduces breast cancer tumor-initiating cells and improves recurrence free survival in a human-xenograft model.

Dave B, Landis MD, Tweardy DJ, Chang JC, Dobrolecki LE, Wu MF, Zhang X, Westbrook TF, Hilsenbeck SG, Liu D, Lewis MT - PLoS ONE (2012)

Bottom Line: Metastasis and disease relapse are hypothesized to result from tumor initiating cells (TICs).Importantly, we observed a four-fold improvement in the 30-day recurrence-free survival relative to docetaxel alone with the addition of the Stat3 inhibitor in the chemoresistant tumor model.Thus, these findings provide a strong impetus for the development of selective Stat3 inhibitors in order to improve survival in patients with p-Stat3 overexpressing tumors.

View Article: PubMed Central - PubMed

Affiliation: The Methodist Cancer Center, Houston, Texas, United States of America.

ABSTRACT
Metastasis and disease relapse are hypothesized to result from tumor initiating cells (TICs). Previously, we have defined a CD44+/CD24-/low mammosphere-forming tumorigenic 493-gene signature in breast cancer. Stat3 was identified as a critical node in self-renewal based on an ongoing lentiviral shRNA screen being conducted in two breast cancer cell lines SUM159 and BT549. In corroborating work, targeting the SH2 domain of Stat3 with a novel small molecule decreased the percentage of cells expressing TIC markers (CD44+/CD24-/low and ALDH+) and mammosphere formation in p-Stat3 overexpressing human breast cancer xenografts in SCID-beige mice. Importantly, we observed a four-fold improvement in the 30-day recurrence-free survival relative to docetaxel alone with the addition of the Stat3 inhibitor in the chemoresistant tumor model. Thus, these findings provide a strong impetus for the development of selective Stat3 inhibitors in order to improve survival in patients with p-Stat3 overexpressing tumors.

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Ingenuity Analysis identifies Stat3 as an important target for TIC self renewal.(A) Ingenuity Analysis of 493-gene tumorigenic stem cell signature, looking for direct and indirect interactions of these genes among themselves identified Stat3 as one of the important targets of TIC self renewal. (B) Mammosphere forming efficiency in SUM159 treated with Stat3 shRNA vs. empty vector (EV) showed a significant decrease (p<0.05). Data depicted as Mean+ SEM. Western analysis of empty vector vs. Stat3 shRNAs treated cells depicts reduction in pStat3 levels upon treatment. (C)Mammosphere forming efficiency for SUM 159 and BT 549 cells treated with C188 at 10 µM concentration. Significant decrease in mammosphere formation upon treatment with C188 (p<0.05). Data depicted as Mean+SEM.
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pone-0030207-g001: Ingenuity Analysis identifies Stat3 as an important target for TIC self renewal.(A) Ingenuity Analysis of 493-gene tumorigenic stem cell signature, looking for direct and indirect interactions of these genes among themselves identified Stat3 as one of the important targets of TIC self renewal. (B) Mammosphere forming efficiency in SUM159 treated with Stat3 shRNA vs. empty vector (EV) showed a significant decrease (p<0.05). Data depicted as Mean+ SEM. Western analysis of empty vector vs. Stat3 shRNAs treated cells depicts reduction in pStat3 levels upon treatment. (C)Mammosphere forming efficiency for SUM 159 and BT 549 cells treated with C188 at 10 µM concentration. Significant decrease in mammosphere formation upon treatment with C188 (p<0.05). Data depicted as Mean+SEM.

Mentions: Ingenuity analysis of the 493-gene tumorigenic gene signature was performed to identify the key nodes and players involved in TIC self renewal. Along with other factors, Stat3 was identified as an important target for TICs (Figure 1A). Further, in ongoing screen of lentivirally expressed shRNAs (pGIPZ-shRNAmir library, Open Biosystems) to disrupt function of candidate regulators of tumor-initiating cells, we identified shRNAs targeting Stat3 decreased mammosphere formation efficacy (MSFE). The shRNAs were tested in two claudin-low cell lines (SUM159 and BT549) using a high throughput 96-well MS formation assay (Figure S1 and Procedures S1). Additionally, we tested three lentivirally targeted Stat3 shRNAs in SUM159 (Fig. 1B) and found that these shRNAs decreased pStat3 levels in 72 hrs. This was associated with a corresponding decrease in MSFE in 4 days. A selective Stat3 inhibitor C188 was tested for effect on MSFE on SUM159 and BT549 cell lines. A significant decrease in MFSE was observed 4 days after treatment, with C188 in both triple negative breast cancer cell lines (Fig. 1C).


Selective small molecule Stat3 inhibitor reduces breast cancer tumor-initiating cells and improves recurrence free survival in a human-xenograft model.

Dave B, Landis MD, Tweardy DJ, Chang JC, Dobrolecki LE, Wu MF, Zhang X, Westbrook TF, Hilsenbeck SG, Liu D, Lewis MT - PLoS ONE (2012)

Ingenuity Analysis identifies Stat3 as an important target for TIC self renewal.(A) Ingenuity Analysis of 493-gene tumorigenic stem cell signature, looking for direct and indirect interactions of these genes among themselves identified Stat3 as one of the important targets of TIC self renewal. (B) Mammosphere forming efficiency in SUM159 treated with Stat3 shRNA vs. empty vector (EV) showed a significant decrease (p<0.05). Data depicted as Mean+ SEM. Western analysis of empty vector vs. Stat3 shRNAs treated cells depicts reduction in pStat3 levels upon treatment. (C)Mammosphere forming efficiency for SUM 159 and BT 549 cells treated with C188 at 10 µM concentration. Significant decrease in mammosphere formation upon treatment with C188 (p<0.05). Data depicted as Mean+SEM.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3412855&req=5

pone-0030207-g001: Ingenuity Analysis identifies Stat3 as an important target for TIC self renewal.(A) Ingenuity Analysis of 493-gene tumorigenic stem cell signature, looking for direct and indirect interactions of these genes among themselves identified Stat3 as one of the important targets of TIC self renewal. (B) Mammosphere forming efficiency in SUM159 treated with Stat3 shRNA vs. empty vector (EV) showed a significant decrease (p<0.05). Data depicted as Mean+ SEM. Western analysis of empty vector vs. Stat3 shRNAs treated cells depicts reduction in pStat3 levels upon treatment. (C)Mammosphere forming efficiency for SUM 159 and BT 549 cells treated with C188 at 10 µM concentration. Significant decrease in mammosphere formation upon treatment with C188 (p<0.05). Data depicted as Mean+SEM.
Mentions: Ingenuity analysis of the 493-gene tumorigenic gene signature was performed to identify the key nodes and players involved in TIC self renewal. Along with other factors, Stat3 was identified as an important target for TICs (Figure 1A). Further, in ongoing screen of lentivirally expressed shRNAs (pGIPZ-shRNAmir library, Open Biosystems) to disrupt function of candidate regulators of tumor-initiating cells, we identified shRNAs targeting Stat3 decreased mammosphere formation efficacy (MSFE). The shRNAs were tested in two claudin-low cell lines (SUM159 and BT549) using a high throughput 96-well MS formation assay (Figure S1 and Procedures S1). Additionally, we tested three lentivirally targeted Stat3 shRNAs in SUM159 (Fig. 1B) and found that these shRNAs decreased pStat3 levels in 72 hrs. This was associated with a corresponding decrease in MSFE in 4 days. A selective Stat3 inhibitor C188 was tested for effect on MSFE on SUM159 and BT549 cell lines. A significant decrease in MFSE was observed 4 days after treatment, with C188 in both triple negative breast cancer cell lines (Fig. 1C).

Bottom Line: Metastasis and disease relapse are hypothesized to result from tumor initiating cells (TICs).Importantly, we observed a four-fold improvement in the 30-day recurrence-free survival relative to docetaxel alone with the addition of the Stat3 inhibitor in the chemoresistant tumor model.Thus, these findings provide a strong impetus for the development of selective Stat3 inhibitors in order to improve survival in patients with p-Stat3 overexpressing tumors.

View Article: PubMed Central - PubMed

Affiliation: The Methodist Cancer Center, Houston, Texas, United States of America.

ABSTRACT
Metastasis and disease relapse are hypothesized to result from tumor initiating cells (TICs). Previously, we have defined a CD44+/CD24-/low mammosphere-forming tumorigenic 493-gene signature in breast cancer. Stat3 was identified as a critical node in self-renewal based on an ongoing lentiviral shRNA screen being conducted in two breast cancer cell lines SUM159 and BT549. In corroborating work, targeting the SH2 domain of Stat3 with a novel small molecule decreased the percentage of cells expressing TIC markers (CD44+/CD24-/low and ALDH+) and mammosphere formation in p-Stat3 overexpressing human breast cancer xenografts in SCID-beige mice. Importantly, we observed a four-fold improvement in the 30-day recurrence-free survival relative to docetaxel alone with the addition of the Stat3 inhibitor in the chemoresistant tumor model. Thus, these findings provide a strong impetus for the development of selective Stat3 inhibitors in order to improve survival in patients with p-Stat3 overexpressing tumors.

Show MeSH
Related in: MedlinePlus