The histone deacetylase inhibitor LBH589 inhibits undifferentiated pleomorphic sarcoma growth via downregulation of FOS-like antigen 1

Establishment and characterization of NCC-PS1-C1: a novel cell line of pleomorphic sarcoma from a patient after neoadjuvant radiotherapy

Pleomorphic sarcoma (PS) is a heterogeneous group of malignant mesenchymal tumors without a specific histological lineage of differentiation. PS is genetically characterized by genetic instability and diversity and histologically characterized by morphological pleomorphism. PS is one of the most common soft tissue sarcomas. The only curative treatment for PS is complete surgical resection, in which neoadjuvant radiotherapy is frequently combined. PS demonstrates both local recurrence and metastasis after surgical treatment, and effective systemic chemotherapy has not yet been established. Patient-derived cancer cell lines are critical tools for basic and preclinical studies in the development of chemotherapy. However, only six PS cell lines are available from the public cell bank, and none of them are derived from PS after neoadjuvant radiotherapy, despite the fact that radiotherapy causes changes in the posttreatment cancer genome. Here, we reported a novel cell line of PS from a primary tumor specimen resected after neoadjuvant radiotherapy and named it NCC-PS1-C1. NCC-PS1-C1 cells showed a variety of copy number alterations and pathological mutations in TP53. NCC-PS1-C1 cells demonstrated constant proliferation, spheroid formation, and invasion capability in vitro. The screening of antitumor agents in NCC-PS1-C1 cells showed that bortezomib and romidepsin were effective against PS. In conclusion, we report a novel PS cell line from a primary tumor resected after neoadjuvant radiotherapy. We believe that NCC-PS1-C1 will be a useful tool for the development of novel chemotherapies for PS, especially for recurrent cases after neoadjuvant radiotherapy.

Establishment and characterization of NCC-UPS3-C1: a novel patient-derived cell line of undifferentiated pleomorphic sarcoma

Undifferentiated pleomorphic sarcoma (UPS), previously termed malignant fibrous histiocytoma, is one of the most aggressive sarcomas with no identifiable line of differentiation. Although the molecular mechanism of oncogenesis in UPS has not been clarified, radiation exposure is considered to be a risk factor in the development of UPS. In the treatment of UPS, surgical treatment remains the most important modality. While chemotherapy is considered in unresectable or metastatic cases, UPS is known to be refractory to conventional chemotherapy, leading to an unfavorable prognosis. To improve the clinical outcome of this condition, novel treatment methods are urgently needed. Patient-derived cell lines are essential tools in preclinical studies. However, owing to the rarity of UPS, only four UPS cell lines are publicly available. Thus, we established a novel UPS cell line, NCC-UPS3-C1, using a surgically resected tumor from a patient with radiation-associated UPS. NCC-UPS3-C1 cells had multiple genomic deletions including the tumor suppressor genes CDKN2A and CDKN2B. NCC-UPS3-C1 cells demonstrated constant growth, spheroid formation, and aggressive invasion ability. We also conducted a screening test using 214 drugs and identified that the histone deacetylase inhibitor, romidepsin, is highly effective on NCC-UPS3-C1 cells. Thus, we concluded that the NCC-UPS3-C1 cell line is a useful tool in preclinical studies for UPS.

Panobinostat penetrates the blood-brain barrier and achieves effective brain concentrations in a murine model

PURPOSE

Panobinostat, an orally bioavailable pan-HDAC inhibitor, has demonstrated potent activity in multiple malignancies, including pediatric brain tumors such as DIPG, with increased activity against H3K27M mutant cell lines. Given limited evidence regarding the CNS penetration of panobinostat, we sought to characterize its BBB penetration in a murine model.

METHODS

Panobinostat 15 mg/kg was administered IV to 12 CD-1 female mice. At specified time points, mice were euthanized, blood samples were collected, and brains were removed. LC-MS was performed to quantify panobinostat concentrations. C_max and AUC were estimated and correlated with previously published pharmacokinetic analyses and reports of IC-50 values in DIPG cell lines.

RESULTS

Mean panobinostat plasma concentrations (ng/mL) were 27.3 ± 2.5 at 1 h, 7.56 ± 1.8 at 2 h, 1.48 ± 0.56 at 4 h, and 2.33 ± 1.18 at 7 h. Mean panobinostat brain concentrations (ng/g) were 60.5 ± 6.1 at 1 h, 42.9 ± 5.4 at 2 h, 33.2 ± 6.1 at 4 h, and 28.1 ± 4.3 at 7 h. Brain-to-plasma ratio at 1 h was 2.22 and the brain to plasma AUC ratio was 2.63. Based on the published human pharmacokinetic data, the anticipated C_max in humans is expected to be significantly higher than the IC-50 identified in DIPG models.

CONCLUSION

It is expected that panobinostat would be effective in CNS tumors where the IC-50 is in the low nanomolar range. Thus, our data demonstrate panobinostat crosses the BBB and achieves concentrations above the IC-50 for DIPG and other brain tumors and should be explored further for clinical efficacy.

Neurotensin receptor 1 is a new therapeutic target for human undifferentiated pleomorphic sarcoma growth

Undifferentiated pleomorphic sarcoma (UPS) is the second most common soft tissue sarcoma. For patients with unresectable or metastatic disease, chemotherapies are considered, but in many cases they are not curative. There is a need to identify specific molecular dysregulations that can be therapeutic targets. We focused on neurotensin receptor 1 (NTSR1), which belongs to the G-protein-coupled receptor. NTSR1 expression was upregulated in specimens from patients with UPS. Real-time polymerase chain reaction showed that expression of NTSR1 messenger RNA was 5- to 7-fold increased in UPS cells compared with myoblasts. Western blot showed a high expression of NTSR1 protein in UPS cell lines. Knockdown of NTSR1 prevented UPS cell proliferation and invasion. We confirmed that SR48692, an inhibitor of NTSR1, exhibited antitumor activities in UPS cells. The combination index showed that SR48692 and standard chemotherapeutic drugs prevented UPS cell proliferation synergistically. Mouse xenograft models showed that SR48692 inhibited extracellular signal-regulated kinase phosphorylation and enhanced the response to standard chemotherapeutic drugs. Inhibition of NTSR1 improved the effect of standard chemotherapeutic drugs for UPS. SR48692 may be a new drug for targeted UPS therapy.

Panobinostat (LBH589) inhibits Wnt/β-catenin signaling pathway via upregulating APCL expression in breast cancer

Breast cancer is the most common malignant disease among women worldwide and the novel therapeutic agents are urgently needed. Panobinostat (LBH589), a pan-HDACs inhibitor, has shown promising anti-tumor effect in recent years. However, the targets of this compound are largely unclear because of its low selectivity. In consideration of the transcription promoting activity of panobinostat, we speculated that specific tumor suppressor genes might be upregulated after panobinostat treatment. In this study, we verified the inhibition effect of panobinostat in different subtypes of breast cancer cells in vivo and in vitro. We found that panobinostat suppressed proliferation, migration as well as invasion, and induced apoptosis in both TNBC and non-TNBC cells. Consistently, panobinostat inhibited breast cancer growth and metastasis in mouse models. Mechanistically, we found APCL transcription and expression was significantly upregulated in panobinostat treated cells by RNA microarray analysis, while knockdown of APCL resulted in reduced sensitivity to panobinostat in breast cancer cells. APCL is a wnt/β-catenin pathway regulator that promotes β-catenin ubiquitylation and degradation. We found that panobinostat inhibited β-catenin expression by increasing its ubiquitylation and thus reducing its half-life. In addition, the expression of β-catenin activated targets including c-Jun, c-Myc, Cyclin D1 and CD44 were also decreased by panobinostat treatment in breast cancer cells. These results suggested that panobinostat inhibited tumor growth and metastasis via upregulating APCL expression in breast cancer cells, which was a novel and crucial mechanism of panobinostat.