OBJECTIVETo investigate the effects of PPARgamma ligand (rosiglitazone, RGZ) as well as combined with all trans-retinoic acid (ATRA) on human myeloma cells and try to explore the possible mechanism.

METHODSHuman myeloma cell lines U266 and RPMI-8226 cells were treated with RGZ in the presence or absence of ATRA. Cell proliferation was evaluated by [(3)H] thymidine incorporation, cell cycle distribution and CD49e expression were analyzed by flow cytometry, morphology changes were evaluated by Wright-Giemsa staining, and p27(Kip1) and p21(Waf1) expression was detected by Western blotting.

RESULTSThe exposure to RGZ induced proliferation inhibition in both cell lines in a dose-dependent manner. After cultured with 5 micromol/L RGZ, the proportion of U266 and RPMI-8226 cells in phase G(0)/G(1) was (45.2 +/- 6.7)% and (40.3 +/- 7.3)%, respectively (P < 0.05). The proportion of the cells in phase G(2)/M and S was (52.2 +/- 7.4)% and (57.4 +/- 9.5)%, respectively (P < 0.05). These changes were more evident when the RGZ concentration was increased to 10 micromol/L. A combination of RGZ with ATRA enhanced the growth inhibition and cell cycle arrest effects of RGZ. The RGZ-treated myeloma cells displayed morphological characteristics of cell differentiation, and more evident signs of differentiation were observed when RGZ was combined with ATRA. These changes were confirmed by the detection of CD49e expression. The expression of p27(Kip1) and p21(Waf1) in myeloma cells was up-regulated by RGZ and this change was more apparent when RGZ was used in combination with ATRA.

CONCLUSIONRGZ can induce cell cycle arrest and cell differentiation in myeloma cells which maybe caused by up-regulation of p27(Kip1) and p21(Waf1) expression. ATRA can enhance these effects of RGZ on multiple myeloma cells and combined use of these two drugs may show a synergistic effect on myeloma cells.

Cell Cycle ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p21 ; metabolism ; Cyclin-Dependent Kinase Inhibitor p27 ; Dose-Response Relationship, Drug ; Drug Synergism ; Humans ; Integrin alpha5 ; metabolism ; Intracellular Signaling Peptides and Proteins ; metabolism ; Multiple Myeloma ; metabolism ; pathology ; PPAR gamma ; agonists ; Thiazolidinediones ; administration & dosage ; pharmacology ; Tretinoin ; pharmacology ; Up-Regulation

Objective: Immune checkpoint inhibitor (ICI) therapy has shown activity against melanoma brain metastases. Recently, promising results have also been reported for ICI combination therapy and ICI combined with radiotherapy. We aimed to evaluate radiologic response and adverse event rates of these therapeutic options by a systematic review and meta-analysis. Materials and Methods: A systematic literature search of Ovid-MEDLINE and EMBASE was performed up to October 12, 2019 and included studies evaluating the intracranial objective response rates (ORRs) and/or disease control rates (DCRs) of ICI with or without radiotherapy for treating melanoma brain metastases. We also evaluated safety-associated outcomes. Results: Eleven studies with 14 cohorts (3 with ICI combination therapy; 5 with ICI combined with radiotherapy; 6 with ICI monotherapy) were included. ICI combination therapy {pooled ORR, 53% (95% confidence interval [CI], 44–61%); DCR, 57% (95% CI, 49–66%)} and ICI combined with radiotherapy (pooled ORR, 42% [95% CI, 31–54%]; DCR, 85% [95% CI, 63–95%]) showed higher local efficacy compared to ICI monotherapy (pooled ORR, 15% [95% CI, 11–20%]; DCR, 26% [95% CI, 21– 32%]). The grade 3 or 4 adverse event rate was significantly higher with ICI combination therapy (60%; 95% CI, 52–67%) compared to ICI monotherapy (11%; 95% CI, 8–17%) and ICI combined with radiotherapy (4%; 95% CI, 1–19%). Grade 3 or 4 central nervous system (CNS)-related adverse event rates were not different (9% in ICI combination therapy; 8% in ICI combined with radiotherapy; 5% in ICI monotherapy). Conclusion ICI combination therapy or ICI combined with radiotherapy showed better local efficacy than ICI monotherapy for treating melanoma brain metastasis. The grade 3 or 4 adverse event rate was highest with ICI combination therapy, and the CNS-related grade 3 or 4 event rate was similar. Prospective trials will be necessary to compare the efficacy of ICI combination therapy and ICI combined with radiotherapy.

Objective: Immune checkpoint inhibitor (ICI) therapy has shown activity against melanoma brain metastases. Recently, promising results have also been reported for ICI combination therapy and ICI combined with radiotherapy. We aimed to evaluate radiologic response and adverse event rates of these therapeutic options by a systematic review and meta-analysis. Materials and Methods: A systematic literature search of Ovid-MEDLINE and EMBASE was performed up to October 12, 2019 and included studies evaluating the intracranial objective response rates (ORRs) and/or disease control rates (DCRs) of ICI with or without radiotherapy for treating melanoma brain metastases. We also evaluated safety-associated outcomes. Results: Eleven studies with 14 cohorts (3 with ICI combination therapy; 5 with ICI combined with radiotherapy; 6 with ICI monotherapy) were included. ICI combination therapy {pooled ORR, 53% (95% confidence interval [CI], 44–61%); DCR, 57% (95% CI, 49–66%)} and ICI combined with radiotherapy (pooled ORR, 42% [95% CI, 31–54%]; DCR, 85% [95% CI, 63–95%]) showed higher local efficacy compared to ICI monotherapy (pooled ORR, 15% [95% CI, 11–20%]; DCR, 26% [95% CI, 21– 32%]). The grade 3 or 4 adverse event rate was significantly higher with ICI combination therapy (60%; 95% CI, 52–67%) compared to ICI monotherapy (11%; 95% CI, 8–17%) and ICI combined with radiotherapy (4%; 95% CI, 1–19%). Grade 3 or 4 central nervous system (CNS)-related adverse event rates were not different (9% in ICI combination therapy; 8% in ICI combined with radiotherapy; 5% in ICI monotherapy). Conclusion ICI combination therapy or ICI combined with radiotherapy showed better local efficacy than ICI monotherapy for treating melanoma brain metastasis. The grade 3 or 4 adverse event rate was highest with ICI combination therapy, and the CNS-related grade 3 or 4 event rate was similar. Prospective trials will be necessary to compare the efficacy of ICI combination therapy and ICI combined with radiotherapy.

OBJECTIVETo observe the effect of rosiglitazone (RGZ) and all-trans-retinoic acid (ATRA) on the growth of myeloma xenograft in nude mice and to explore the influence of RGZ and ATRA on VEGF expression and angiogenesis in the tumor.

METHODSVEGF gene expression in myeloma cell line U266 cells was analyzed by semi-quantitative RT-PCR after incubation with RGZ, ATRA, or RGZ + ATRA for 24 h. Myeloma xenograft was established by subcutaneous injection of 10(7) U266 cells in the scapula area of 4-week old nude mice. 7 days later, the nude mice were administered with RGZ, ATRA or RGZ + ATRA, respectively, by intraperitoneal injection once every day for 21 days. The control mice were given equal volume of normal saline instead of the drug. On the 21(st) day of treatment, the mice were sacrificed and the tumors were taken off, and the tumor volume and weight were measured. The tumors were examined by histopathology with HE staining, and microvessel density (MVD), CD34 and VEGF expression in the tumors were analyzed by immunohistochemical staining.

RESULTSVEGF mRNA was highly expressed in U266 cells and was decreased in a dose-dependent manner after incubation with RGZ. The VEGF mRNA level was further more decreased after RGZ + ATRA treatment. Xenografts of U266 cells were developed in all nude mice. The volume and weight of xenografts in the RGZ group were (785 ± 262) mm(3) and (1748 ± 365) mg, respectively, significantly lower than those of the control group (both P < 0.01). More significant inhibition was in the RGZ + ATRA group, (154 ± 89) mm(3) and (626 ± 102) mg, respectively, both were P < 0.05 vs. the RGZ group. RGZ inhibited the angiogenesis in U266 xenografts and immunohistochemical staining showed that the tumor MVD and VEGF expression were significantly decreased by RGZ treatment, and further more inhibited in the RGZ + ATRA group. VEGF protein was expressed in all xenografts in the nude mice. Its immunohistochemical staining intensity was 2.20 ± 0.40 in the control group, significantly higher than that of 1.48 ± 0.37 in the RGZ group (P < 0.01), and that of RGZ + ATRA group was 0.58 ± 0.26, further significantly lower than that of the RGZ group (P < 0.01). CD34 was expressed in all xenografts, most highly in the control group and lowest in the RGZ + ATRA group. The microvessel density (MVD) was highest in the control group (56.4 ± 15.2), significantly lower in the RGZ group (44.6 ± 11.2) (P < 0.05), and lowest in the RGZ + ATRA group (21.5 ± 8.6, P < 0.01).

CONCLUSIONSThe growth of myeloma cells can also be inhibited by RGZ and ATRA in nude mice in vivo. In addition to differentiation and apoptosis induction, RGZ can inhibit the formation of myeloma xenograft probably also through the downregulation of VEGF expression and subsequent angiogenesis.

Animals ; Antigens, CD34 ; metabolism ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Dose-Response Relationship, Drug ; Drug Synergism ; Female ; Humans ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Microvessels ; pathology ; Multiple Myeloma ; metabolism ; pathology ; Neoplasm Transplantation ; Neovascularization, Pathologic ; RNA, Messenger ; metabolism ; Thiazolidinediones ; administration & dosage ; pharmacology ; Tretinoin ; pharmacology ; Tumor Burden ; drug effects ; Vascular Endothelial Growth Factor A ; genetics ; metabolism ; Xenograft Model Antitumor Assays