buparlisib and trametinib

MAPK and PI3K/AKT/mTOR pathways play important roles in many tumors. In this study, safety, antitumor activity, and pharmacokinetics of buparlisib (pan class PI3K inhibitor) and trametinib (MEK inhibitor) were evaluated.. This open-label, dose-finding, phase Ib study comprised dose escalation, followed by expansion part in patients with RAS- or BRAF-mutant non-small cell lung, ovarian, or pancreatic cancer.. Of note, 113 patients were enrolled, 66 and 47 in dose-escalation and -expansion parts, respectively. MTD was established as buparlisib 70 mg + trametinib 1.5 mg daily [5/15, 33% patients with dose-limiting toxicities (DLT)] and recommended phase II dose (RP2D) buparlisib 60 mg + trametinib 1.5 mg daily (1/10, 10% patients with DLTs). DLTs included stomatitis (8/103, 8%), diarrhea, dysphagia, and creatine kinase (CK) increase (2/103, 2% each). Treatment-related grade 3/4 adverse events (AEs) occurred in 73 patients (65%); mainly CK increase, stomatitis, AST/ALT (aspartate aminotransferase/alanine aminotransferase) increase, and rash. For all (21) patients with ovarian cancer, overall response rate was 29% [1 complete response, 5 partial responses (PR)], disease control rate 76%, and median progression-free survival was 7 months. Minimal activity was observed in patients with non-small cell lung cancer (1/17 PR) and pancreatic cancer (best overall response was SD). Relative to historical data, buparlisib exposure increased and trametinib exposure slightly increased with the combination.. At RP2D, buparlisib 60 mg + trametinib 1.5 mg daily shows promising antitumor activity for patients with KRAS-mutant ovarian cancer. Long-term tolerability of the combination at RP2D is challenging, due to frequent dose interruptions and reductions for toxicity.

Topics: Adult; Aged; Aged, 80 and over; Aminopyridines; Antineoplastic Combined Chemotherapy Protocols; Disease-Free Survival; Dose-Response Relationship, Drug; Female; Humans; Male; Maximum Tolerated Dose; Middle Aged; Morpholines; Neoplasms; Pyridones; Pyrimidinones

Malignant melanoma is the most aggressive type of skin cancer and is closely associated with the development of brain metastases. Despite aggressive treatment, the prognosis has traditionally been poor, necessitating improved therapies. In melanoma, the mitogen activated protein kinase and the phosphoinositide 3-kinase signaling pathways are commonly altered, and therapeutically inhibiting one of the pathways often upregulates the other, leading to resistance. Thus, combined treatment targeting both pathways is a promising strategy to overcome this. Here, we studied the in vitro and in vivo effects of the PI3K inhibitor buparlisib and the MEK1/2 inhibitor trametinib, used either as targeted monotherapies or in combination, on patient-derived melanoma brain metastasis cell lines. Scratch wound and trans-well assays were carried out to assess the migratory capacity of the cells upon drug treatment, whereas flow cytometry, apoptosis array and Western blots were used to study apoptosis. Finally, an in vivo treatment experiment was carried out on NOD/SCID mice. We show that combined therapy was more effective than monotherapy. Combined treatment also more effectively increased apoptosis, and inhibited tumor growth in vivo. This suggests a clinical potential of combined treatment to overcome ceased treatment activity which is often seen after monotherapies, and strongly encourages the evaluation of the treatment strategy on melanoma patients with brain metastases.

Topics: Aminopyridines; Animals; Antineoplastic Combined Chemotherapy Protocols; Brain Neoplasms; Cell Line, Tumor; Melanoma; Mice, Inbred NOD; Mice, SCID; Mitogen-Activated Protein Kinases; Morpholines; Phosphatidylinositol 3-Kinases; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; Signal Transduction; Skin Neoplasms; Treatment Outcome; Tumor Burden; Xenograft Model Antitumor Assays

Hyperactivation of phosphatidylinositol 3-kinase (PI3K) pathway occurs frequently in head and neck squamous cell carcinoma (HNSCC). However, clinical outcomes of targeting the PI3K pathway have been underwhelming. In present study, we investigated the resistant mechanisms and potential combination therapeutic strategy to overcome adaptive resistance to PI3K inhibitor in HNSCC. Treatment of NVP-BKM120, a pan-PI3K inhibitor, led to upregulation of interleukin-6 (IL-6) and subsequent activation of either extracellular signal-regulated kinase (ERK) or signal transducers and activators of transcription 3 (STAT3), causing modest antitumor effects on the growth of HNSCC cells. Blockade of autocrine IL-6 signaling with siRNA or neutralizing antibody for IL-6 receptor (IL-6R) completely abolished NVP-BKM120-induced activation of ERK and STAT3 as well as expression of c-Myc oncogene, which resulted in enhanced sensitivity to NVP-BKM120. Moreover, when compared with a pharmacologic inhibitor or silencing of STAT3, trametinib, a MEK inhibitor, in combination with NVP-BKM120 yielded more potent anti-proliferative effects by inhibiting S phase transition, arresting cells at G0/G1 phase, and downregulating IL-6 and c-Myc expression. Furthermore, as compared with either agent alone, combination of NVP-BKM120 with trametinib or tocilizumab, a humanized anti-IL-6R antibody, significantly suppressed tumor growth in NVP-BKM120-resistant patient-derived tumor xenograft (PDTX) models, which was also confirmed in PDTX-derived cell lines. Collectively, these results suggested that IL-6/ERK signaling is closely involved in adaptive resistance of NVP-BKM120 in HNSCC cells, providing a rationale for a novel combination therapy to overcome resistance to PI3K inhibitors.

Topics: Aminopyridines; Animals; Antibodies, Monoclonal, Humanized; Antineoplastic Combined Chemotherapy Protocols; Autocrine Communication; Carcinoma, Squamous Cell; Cell Line, Tumor; Cell Proliferation; Drug Resistance, Neoplasm; Extracellular Signal-Regulated MAP Kinases; Female; Head and Neck Neoplasms; Humans; Interleukin-6; MAP Kinase Signaling System; Mice; Mice, Inbred NOD; Morpholines; Phosphatidylinositol 3-Kinases; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Pyridones; Pyrimidinones; Receptors, Interleukin-6; RNA, Small Interfering; Squamous Cell Carcinoma of Head and Neck; STAT3 Transcription Factor; Xenograft Model Antitumor Assays

The PI3K/AKT/mTOR pathway plays a crucial role in the development of leiomyosarcomas (LMSs). In this study, we tested the efficacy of dual PI3K/mTOR (BEZ235), PI3K (BKM120) and mTOR (everolimus) inhibitors in three human LMS cell lines. In vitro and in vivo studies using LMS cell lines showed that BEZ235 has a significantly higher anti-tumor effect than either BKM120 or everolimus, resulting in a greater reduction in tumor growth and more pronounced inhibitory effects on mitotic activity and PI3K/AKT/mTOR signaling. Strikingly, BEZ235 but neither BKM120 nor everolimus markedly enhanced the ERK pathway. This effect was reproduced by the combination of BKM120 and everolimus, suggesting the involvement of mTORC2 via a PI3K-independent mechanism. Silencing of RICTOR in LMS cells confirmed the role of mTORC2 in the regulation of ERK activity. Combined treatment with BEZ235 and GSK1120212, a potent MEK inhibitor, resulted in synergistic growth inhibition and apoptosis induction in vitro and in vivo. These findings document for the first time that dual PI3K/mTOR inhibition in leiomyosarcomas suppress a negative feedback loop mediated by mTORC2, leading to enhanced ERK pathway activity. Thus, combining a dual PI3K/mTOR inhibitor with MEK inhibitors may be a relevant approach to increase anti-tumor activity and prevent drug resistance in patients with LMS.

Topics: Aminopyridines; Animals; Antineoplastic Combined Chemotherapy Protocols; Apoptosis; Cell Line, Tumor; Cell Proliferation; Dose-Response Relationship, Drug; Drug Synergism; Enzyme Activation; Everolimus; Extracellular Signal-Regulated MAP Kinases; Humans; Imidazoles; Leiomyosarcoma; MAP Kinase Kinase Kinases; Mechanistic Target of Rapamycin Complex 2; Mice; Morpholines; Phosphatidylinositol 3-Kinase; Phosphoinositide-3 Kinase Inhibitors; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-akt; Pyridones; Pyrimidinones; Quinolines; Rapamycin-Insensitive Companion of mTOR Protein; RNA Interference; Signal Transduction; Time Factors; TOR Serine-Threonine Kinases; Transfection; Tumor Burden; Xenograft Model Antitumor Assays

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.

Topics: Aminopyridines; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Class I Phosphatidylinositol 3-Kinases; Drug Synergism; Extracellular Signal-Regulated MAP Kinases; Humans; Mechanistic Target of Rapamycin Complex 1; Morpholines; Multiprotein Complexes; Mutation; Osteosarcoma; Phosphorylation; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Pyridones; Pyrimidines; Pyrimidinones; Pyrroles; Sarcoma; Signal Transduction; TOR Serine-Threonine Kinases