Limits...
Evaluation of In Vitro Activity of the Class I PI3K Inhibitor Buparlisib (BKM120) in Pediatric Bone and Soft Tissue Sarcomas.

Anderson JL, Park A, Akiyama R, Tap WD, Denny CT, Federman N - PLoS ONE (2015)

Bottom Line: Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment.Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination.The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Division of Hematology/Oncology, Gwynne Hazen Cherry Memorial Laboratories, University of California, Los Angeles, Los Angeles, California, United States of America.

ABSTRACT
Pediatric bone and soft tissue sarcomas often display increased Akt phosphorylation through up regulation of insulin-like growth factor (IGF1) signaling. Additionally, Akt signaling has been linked to resistance to IGF1 receptor (IGF1R) and mTOR (mammalian target of rapamycin) inhibitors in sarcoma, further demonstrating the role of Akt in tumor survival. This suggests targeting components of the PI3K/Akt pathway may be an effective therapeutic strategy. Here, we investigated the in vitro activity of the pan-class I PI3K inhibitor buparlisib (BKM120) in pediatric bone and soft tissue sarcomas. Buparlisib inhibited activation of Akt and signaling molecules downstream of mTORC1 (mTOR complex 1) in Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma cell lines. Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment. Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination. Synergy was observed when buparlisib was combined with the IGF1R inhibitor NVP-AEW541 and the mTORC1 inhibitor rapamycin. The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone. Additionally, the combination of buparlisib with the MEK1/2 inhibitor trametinib resulted in synergy in sarcoma cell lines possessing MAPK pathway mutations. Taken together, these data indicate buparlisib could be a novel therapy for the treatment of pediatric bone and soft tissue sarcomas.

No MeSH data available.


Related in: MedlinePlus

Buparlisib synergizes with trametinib in cell lines harboring MAPK pathway mutations.(A) Cell lines with (A673, RD) and without (TC-32, A4573) MAPK pathway mutations were exposed to a series of 1.5-fold dilutions of buparlisib and trametinib alone or in combination at a constant ratio of 1:15 for 72 hours, then cell viability was determined by MTT assay. Columns represent the average of three independent experiments, error bars represent standard deviation. Combination index values greater than 1, equal to 1, or less than one indicate antagonism, additivity, or synergy. (B) Isobologram plot of the effect of buparlisib combined with trametinib. The effective doses of trametinib and buparlisib are plotted on the x- and y-axis, respectively. Points for combination treatment above, on, or below the lines indicate antagonism, additivity, or synergy with lines of linear additivity connecting the ED50, ED75, and E90 for individual treatments. Isobologram could not be generated for TC-32 cells since no tramenitib cytotoxicity was observed. (C) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204, T185/187), and total Erk1/2 in A673 cells after 1 hour of treatment with buparlisib, trametinib, or both. (D) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204 on Erk1, T185/187 on Erk2), total Erk1/2, cleaved PARP, and actin in A673 cells after 24 hours of treatment with buparlisib, trametinib, or both.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4581723&req=5

pone.0133610.g008: Buparlisib synergizes with trametinib in cell lines harboring MAPK pathway mutations.(A) Cell lines with (A673, RD) and without (TC-32, A4573) MAPK pathway mutations were exposed to a series of 1.5-fold dilutions of buparlisib and trametinib alone or in combination at a constant ratio of 1:15 for 72 hours, then cell viability was determined by MTT assay. Columns represent the average of three independent experiments, error bars represent standard deviation. Combination index values greater than 1, equal to 1, or less than one indicate antagonism, additivity, or synergy. (B) Isobologram plot of the effect of buparlisib combined with trametinib. The effective doses of trametinib and buparlisib are plotted on the x- and y-axis, respectively. Points for combination treatment above, on, or below the lines indicate antagonism, additivity, or synergy with lines of linear additivity connecting the ED50, ED75, and E90 for individual treatments. Isobologram could not be generated for TC-32 cells since no tramenitib cytotoxicity was observed. (C) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204, T185/187), and total Erk1/2 in A673 cells after 1 hour of treatment with buparlisib, trametinib, or both. (D) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204 on Erk1, T185/187 on Erk2), total Erk1/2, cleaved PARP, and actin in A673 cells after 24 hours of treatment with buparlisib, trametinib, or both.

Mentions: MAPK mutations in sarcoma cell lines as well as increased Erk activity after buparlisib treatment suggested the addition of an agent targeting the MAPK pathway may also increase buparlisib efficacy. Buparlisib was combined with the MEK1/2 inhibitor trametinib in cell lines with (A673, RD) and without (TC-32, A4573) mutations in the MAPK pathway. Synergistic effects were only observed in cell lines that contained MAPK pathway mutations (Fig 8A and 8B). However, despite inhibition of both Akt and Erk phosphorylation when cells are treated with buparlisib and trametinib, no increase in apoptosis as measured by PARP cleavage was observed compared to treatment with buparlisib alone (Fig 8C and 8D).


Evaluation of In Vitro Activity of the Class I PI3K Inhibitor Buparlisib (BKM120) in Pediatric Bone and Soft Tissue Sarcomas.

Anderson JL, Park A, Akiyama R, Tap WD, Denny CT, Federman N - PLoS ONE (2015)

Buparlisib synergizes with trametinib in cell lines harboring MAPK pathway mutations.(A) Cell lines with (A673, RD) and without (TC-32, A4573) MAPK pathway mutations were exposed to a series of 1.5-fold dilutions of buparlisib and trametinib alone or in combination at a constant ratio of 1:15 for 72 hours, then cell viability was determined by MTT assay. Columns represent the average of three independent experiments, error bars represent standard deviation. Combination index values greater than 1, equal to 1, or less than one indicate antagonism, additivity, or synergy. (B) Isobologram plot of the effect of buparlisib combined with trametinib. The effective doses of trametinib and buparlisib are plotted on the x- and y-axis, respectively. Points for combination treatment above, on, or below the lines indicate antagonism, additivity, or synergy with lines of linear additivity connecting the ED50, ED75, and E90 for individual treatments. Isobologram could not be generated for TC-32 cells since no tramenitib cytotoxicity was observed. (C) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204, T185/187), and total Erk1/2 in A673 cells after 1 hour of treatment with buparlisib, trametinib, or both. (D) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204 on Erk1, T185/187 on Erk2), total Erk1/2, cleaved PARP, and actin in A673 cells after 24 hours of treatment with buparlisib, trametinib, or both.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4581723&req=5

pone.0133610.g008: Buparlisib synergizes with trametinib in cell lines harboring MAPK pathway mutations.(A) Cell lines with (A673, RD) and without (TC-32, A4573) MAPK pathway mutations were exposed to a series of 1.5-fold dilutions of buparlisib and trametinib alone or in combination at a constant ratio of 1:15 for 72 hours, then cell viability was determined by MTT assay. Columns represent the average of three independent experiments, error bars represent standard deviation. Combination index values greater than 1, equal to 1, or less than one indicate antagonism, additivity, or synergy. (B) Isobologram plot of the effect of buparlisib combined with trametinib. The effective doses of trametinib and buparlisib are plotted on the x- and y-axis, respectively. Points for combination treatment above, on, or below the lines indicate antagonism, additivity, or synergy with lines of linear additivity connecting the ED50, ED75, and E90 for individual treatments. Isobologram could not be generated for TC-32 cells since no tramenitib cytotoxicity was observed. (C) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204, T185/187), and total Erk1/2 in A673 cells after 1 hour of treatment with buparlisib, trametinib, or both. (D) Immunoblot analysis of phospho-Akt (S473), total Akt, phospho-Erk1/2 (T202/204 on Erk1, T185/187 on Erk2), total Erk1/2, cleaved PARP, and actin in A673 cells after 24 hours of treatment with buparlisib, trametinib, or both.
Mentions: MAPK mutations in sarcoma cell lines as well as increased Erk activity after buparlisib treatment suggested the addition of an agent targeting the MAPK pathway may also increase buparlisib efficacy. Buparlisib was combined with the MEK1/2 inhibitor trametinib in cell lines with (A673, RD) and without (TC-32, A4573) mutations in the MAPK pathway. Synergistic effects were only observed in cell lines that contained MAPK pathway mutations (Fig 8A and 8B). However, despite inhibition of both Akt and Erk phosphorylation when cells are treated with buparlisib and trametinib, no increase in apoptosis as measured by PARP cleavage was observed compared to treatment with buparlisib alone (Fig 8C and 8D).

Bottom Line: Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment.Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination.The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Division of Hematology/Oncology, Gwynne Hazen Cherry Memorial Laboratories, University of California, Los Angeles, Los Angeles, California, United States of America.

ABSTRACT
Pediatric bone and soft tissue sarcomas often display increased Akt phosphorylation through up regulation of insulin-like growth factor (IGF1) signaling. Additionally, Akt signaling has been linked to resistance to IGF1 receptor (IGF1R) and mTOR (mammalian target of rapamycin) inhibitors in sarcoma, further demonstrating the role of Akt in tumor survival. This suggests targeting components of the PI3K/Akt pathway may be an effective therapeutic strategy. Here, we investigated the in vitro activity of the pan-class I PI3K inhibitor buparlisib (BKM120) in pediatric bone and soft tissue sarcomas. Buparlisib inhibited activation of Akt and signaling molecules downstream of mTORC1 (mTOR complex 1) in Ewing sarcoma, osteosarcoma, and rhabdomyosarcoma cell lines. Anti-proliferative effects were observed in both anchorage dependent and independent conditions and apoptosis was induced within 24 hours of drug treatment. Buparlisib demonstrated cytotoxicity as a single agent, but was found to be more effective when used in combination. Synergy was observed when buparlisib was combined with the IGF1R inhibitor NVP-AEW541 and the mTORC1 inhibitor rapamycin. The addition of NVP-AEW541 also further reduced phospho-Akt levels and more potently induced apoptosis compared to buparlisib treatment alone. Additionally, the combination of buparlisib with the MEK1/2 inhibitor trametinib resulted in synergy in sarcoma cell lines possessing MAPK pathway mutations. Taken together, these data indicate buparlisib could be a novel therapy for the treatment of pediatric bone and soft tissue sarcomas.

No MeSH data available.


Related in: MedlinePlus