MS-275 (Entinostat) Promotes Radio-Sensitivity in PAX3-FOXO1 Rhabdomyosarcoma Cells

Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of childhood. About 25% of RMS expresses fusion oncoproteins such as PAX3/PAX7-FOXO1 (fusion-positive, FP) while fusion-negative (FN)-RMS harbors RAS mutations. Radiotherapy (RT) plays a crucial role in local control but metastatic RMS is often radio-resistant. HDAC inhibitors (HDACi) radio-sensitize different cancer cells types. Thus, we evaluated MS-275 (Entinostat), a Class I and IV HDACi, in combination with RT on RMS cells in vitro and in vivo. MS-275 reversibly hampered cell survival in vitro in FN-RMS RD (RASmut) and irreversibly in FP-RMS RH30 cell lines down-regulating cyclin A, B, and D1, up-regulating p21 and p27 and reducing ERKs activity, and c-Myc expression in RD and PI3K/Akt/mTOR activity and N-Myc expression in RH30 cells. Further, MS-275 and RT combination reduced colony formation ability of RH30 cells. In both cell lines, co-treatment increased DNA damage repair inhibition and reactive oxygen species formation, down-regulated NRF2, SOD, CAT and GPx4 anti-oxidant genes and improved RT ability to induce G2 growth arrest. MS-275 inhibited in vivo growth of RH30 cells and completely prevented the growth of RT-unresponsive RH30 xenografts when combined with radiation. Thus, MS-275 could be considered as a radio-sensitizing agent for the treatment of intrinsically radio-resistant PAX3-FOXO1 RMS.

Progression and Differentiation of Alveolar Rhabdomyosarcoma Is Regulated by PAX7 Transcription Factor—Significance of Tumor Subclones

Rhabdomyosarcoma (RMS), is the most frequent soft tissue tumor in children that originates from disturbances in differentiation process. Mechanisms leading to the development of RMS are still poorly understood. Therefore, by analysis of two RMS RH30 cell line subclones, one subclone PAX7 negative, while the second one PAX7 positive, and comparison with other RMS cell lines we aimed at identifying new mechanisms crucial for RMS progression. RH30 subclones were characterized by the same STR profile, but different morphology, rate of proliferation, migration activity and chemotactic abilities in vitro, as well as differences in tumor morphology and growth in vivo. Our analysis indicated a different level of expression of adhesion molecules (e.g., from VLA and ICAM families), myogenic microRNAs, such as miR-206 and transcription factors, such as MYOD, MYOG, SIX1, and ID. Silencing of PAX7 transcription factor with siRNA confirmed the crucial role of PAX7 transcription factor in proliferation, differentiation and migration of RMS cells. To conclude, our results suggest that tumor cell lines with the same STR profile can produce subclones that differ in many features and indicate crucial roles of PAX7 and ID proteins in the development of RMS.

Isolation of Anemonin from Pulsatilla wallichiana and its Biological Activities

The phytochemical work on Pulsatilla wallichiana Ulbr. (Ranunculaceae Juss.) afforded a dilactone, anemonin (1) isolated, purified and identified by spectroscopic methods and comparison of their spectral data with the reported data. To the best of our knowledge, this compound was isolated for the first time from Pulsatilla wallichiana Ulbr. Moreover, the aqueous (aq.) methanolic extract of the whole plant sample of Pulsatilla wallichiana Ulbr. (PWW) and the methanolic extract of the whole plant sample of Physochlaina praealta (Decne.) Miers (Solanaceae Juss.; PPM) were also investigated for several biological activities including antifungal, antiinflammatory, anticancer (Rh30, Hela, 3T3), cytotoxic, phytotoxic, brine shrimp lethality and insecticidal activities. PWW showed insignificant antifungal while higher anti-inflammatory activity as compared to PPM. In anticancer activity, PWW showed a concentration dependent effect on Rh30 cell viability while both samples exhibited moderate phytotoxic activity.