Effect of cabazitaxel on the growth of human castration-refractory prostate cancer cells in vitro compared to docetaxel and on the anti-tumor properties of the angio-inhibitor PEDF in vivo.

2015 ◽  
Vol 33 (7_suppl) ◽  
pp. 205-205
Author(s):  
Thomas Nelius ◽  
Courtney Jarvis ◽  
Dalia Martinez-Marin ◽  
Stephanie Filleur
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Cell Lines ◽  
In Vitro Cytotoxicity ◽  
In Vivo Studies ◽  
Raw264.7 Macrophages

205 Background: Docetaxel/DTX and cabazitaxel/CBZ have shown promise in the treatment of metastatic Castration-Refractory Prostate Cancer/mCPRC however, comparative studies are missing. Toxicities of these drugs are significant, urging the need to modify taxane regimens. Recently, low-dose metronomic/LDM treatments using conventional chemotherapeutic drugs have shown benefits in CPRC in improving the effect of anti-angiogenic agents. Previously, we have demonstrated that LDM-DTX in combination with PEDF curbs significantly CRPC growth, limits metastases formation and prolongs survival in vivo. In this study, we intended to compare the cytotoxic effect of CBZ and DTX on CRPC cells in vitro and CL1 tumors in vivo. Methods: PC3, DU145 cell lines were from ATCC.CL1 cells were obtained from androgen-deprived LNCaP cells. Cell proliferation was assessed by crystal violet staining and cell cycle analyses. In vitro cytotoxicity assays were performed on CL1 cells/RAW264.7 macrophages co-cultures treated with PEDF and increasing doses of taxanes. For the in vivo studies, CL1 cells were engineered to stably express the DsRed Express protein +/- PEDF. PEDF anti-tumor effects were assessed on s.c. xenografts treated with DTX (5mg/kg ip ev. 4 day) as reference, CBZ (5mg/kg ip ev. 4 days, 1mg/kg for 10 days, 0.5mg/kg q.a.d. and 0.1mg/kg daily) or placebo. Results: CBZ limits cell proliferation with a greater efficacy than DTX in all CRPC cell lines tested. DU145 presented the largest difference. High doses of taxane blocked tumor cells in mitosis, whereas LDM increased the SubG1 population. This effect was significantly higher in DU145 cells treated with CBZ. In vivo, 5mg/kg CBZ delayed tumor growth more efficiently than 5mg/kg DTX. PEDF/5mg/kg CBZ markedly delayed tumor growth compared to all treatments. Finally, engulfment of tumor cells by macrophages was higher in combined treatments suggesting an inflammation-related process. Conclusions: CBZ is more efficient than DTX both in vitro and in vivo.The data also reinforce PEDF as a promising anti-neoplasic agent in combination with LDM taxane chemotherapies.

scholarly journals Activation of the KDM5A/miRNA-495/YTHDF2/m6A-MOB3B axis facilitates prostate cancer progression

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
Chen Du ◽  
Caihong Lv ◽  
Yue Feng ◽  
Siwen Yu
Keyword(s):  
Prostate Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Cell Lines ◽  
Cancer Progression ◽  
Ectopic Expression ◽  
Luciferase Reporter ◽  
Migration And Invasion

Abstract Background Accumulating evidence supports that lysine-specific demethylase 5 (KDM5) family members act as oncogenic drivers. This study was performed to elucidate the potential effects of KDM5A on prostate cancer (PCa) progression via the miR-495/YTHDF2/m6A-MOB3B axis. Methods The expression of KDM5A, miR-495, YTHDF2 and MOB3B was validated in human PCa tissues and cell lines. Ectopic expression and knockdown experiments were developed in PCa cells to evaluate their effects on PCa cell proliferation, migration, invasion and apoptosis. Mechanistic insights into the interaction among KDM5A, miR-495, YTHDF2 and MOB3B were obtained after dual luciferase reporter, ChIP, and PAR-CLIP assays. Me-RIP assay was used to determine m6A modification level of MOB3B mRNA in PCa cells. Mouse xenograft models of PCa cells were also established to monitor the tumor growth. Results KDM5A was highly expressed in human PCa tissues and cell lines. Upregulated KDM5A stimulated PCa cell proliferation, migration and invasion, but reduced cell apoptosis. Mechanistically, KDM5A, as a H3K4me3 demethylase, bound to the miR-495 promoter, which led to inhibition of its transcription and expression. As a target of miR-495, YTHDF2 could inhibit MOB3B expression by recognizing m6A modification of MOB3B mRNA and inducing mRNA degradation. Furthermore, KDM5A was found to downregulate MOB3B expression, consequently augmenting PCa cell proliferation, migration and invasion in vitro and promoting tumor growth in vivo via the miR-495/YTHDF2 axis. Conclusion In summary, our study highlights the potential of histone demethylase KDM5A activity in enhancing PCa progression, and suggests KDM5A as a promising target for PCa treatment.

ANTITUMOR EFFECT OF COLLOIDAL SILVER BISILICATE IN EXPERIMENTAL IN VITRO AND IN VIVO STUDIES

2019 ◽  
Vol 65 (5) ◽  
pp. 760-765
Author(s):  
Margarita Tyndyk ◽  
Irina Popovich ◽  
A. Malek ◽  
R. Samsonov ◽  
N. Germanov ◽  
...  
Keyword(s):  
Antitumor Activity ◽  
Tumor Growth ◽  
Tumor Cells ◽  
Human Tumor ◽  
Significant Inhibition ◽  
In Vivo Studies ◽  
Ehrlich Carcinoma ◽  
In Vivo Experiments

The paper presents the results of the research on the antitumor activity of a new drug - atomic clusters of silver (ACS), the colloidal solution of nanostructured silver bisilicate Ag6Si2O7 with particles size of 1-2 nm in deionized water. In vitro studies to evaluate the effect of various ACS concentrations in human tumor cells cultures (breast cancer, colon carcinoma and prostate cancer) were conducted. The highest antitumor activity of ACS was observed in dilutions from 2.7 mg/l to 5.1 mg/l, resulting in the death of tumor cells in all studied cell cultures. In vivo experiments on transplanted Ehrlich carcinoma model in mice consuming 0.75 mg/kg ACS with drinking water revealed significant inhibition of tumor growth since the 14th day of experiment (maximally by 52% on the 28th day, p < 0.05) in comparison with control. Subcutaneous injections of 2.5 mg/kg ACS inhibited Ehrlich's tumor growth on the 7th and 10th days of the experiment (p < 0.05) as compared to control.

scholarly journals Long non-coding RNA PTPRG-AS1 promotes cell tumorigenicity in epithelial ovarian cancer by decoying microRNA-545-3p and consequently enhancing HDAC4 expression

2020 ◽  
Author(s):  
Juanjuan Shi ◽  
Xijian Xu ◽  
Dan Zhang ◽  
Jiuyan Zhang ◽  
Hui Yang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Epithelial Ovarian Cancer ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Non Coding Rna ◽  
Long Non Coding Rna

Abstract Background: Long non-coding RNA PTPRG antisense RNA 1 (PTPRG-AS1) deregulation has been reported in various human malignancies and identified as an important modulator of cancer development. Few reports have focused on the detailed role of PTPRG-AS1 in epithelial ovarian cancer (EOC) and its underlying mechanism. This study aimed to determine the physiological function of PTPRG-AS1 in EOC. A series of experiments were also performed to identify the mechanisms through which PTPRG-AS1 exerts its function in EOC.Methods: Reverse transcription-quantitative polymerase chain reaction was used to determine PTPRG-AS1 expression in EOC tissues and cell lines. PTPRG-AS1 was silenced in EOC cells and studied with respect to cell proliferation, apoptosis, migration, and invasion in vitro and tumor growth in vivo. The putative miRNAs that target PTPRG-AS1 were predicted using bioinformatics analysis and further confirmed in luciferase reporter and RNA immunoprecipitation assays.Results: Our data verified the upregulation of PTPRG-AS1 in EOC tissues and cell lines. High PTPRG-AS1 expression was associated with shorter overall survival in patients with EOC. Functionally, EOC cell proliferation, migration, invasion in vitro, and tumor growth in vivo were suppressed by PTPRG-AS1 silencing. In contrast, cell apoptosis was promoted by loss of PTPRG-AS1. Regarding the mechanism, PTPRG-AS1 could serve as a competing endogenous RNA in EOC cells by decoying microRNA-545-3p (miR-545-3p), thereby elevating histone deacetylase 4 (HDAC4) expression. Furthermore, rescue experiments revealed that PTPRG-AS1 knockdown-mediated effects on EOC cells were, in part, counteracted by the inhibition of miR-545-3p or restoration of HDAC4.Conclusions: PTPRG-AS1 functioned as an oncogenic lncRNA that aggravated the malignancy of EOC through the miR-545-3p/HDAC4 ceRNA network. Thus, targeting the PTPRG-AS1/miR-545-3p/HDAC4 pathway may be a novel strategy for EOC anticancer therapy.

scholarly journals Tumor quiescence: elevating SOX2 in diverse tumor cell types downregulates a broad spectrum of the cell cycle machinery and inhibits tumor growth

BMC Cancer ◽  
2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Ethan P. Metz ◽  
Erin L. Wuebben ◽  
Phillip J. Wilder ◽  
Jesse L. Cox ◽  
Kaustubh Datta ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Tumor Cell ◽  
Tumor Cells ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Cell Cycle Machinery

Abstract Background Quiescent tumor cells pose a major clinical challenge due to their ability to resist conventional chemotherapies and to drive tumor recurrence. Understanding the molecular mechanisms that promote quiescence of tumor cells could help identify therapies to eliminate these cells. Significantly, recent studies have determined that the function of SOX2 in cancer cells is highly dose dependent. Specifically, SOX2 levels in tumor cells are optimized to promote tumor growth: knocking down or elevating SOX2 inhibits proliferation. Furthermore, recent studies have shown that quiescent tumor cells express higher levels of SOX2 compared to adjacent proliferating cells. Currently, the mechanisms through which elevated levels of SOX2 restrict tumor cell proliferation have not been characterized. Methods To understand how elevated levels of SOX2 restrict the proliferation of tumor cells, we engineered diverse types of tumor cells for inducible overexpression of SOX2. Using these cells, we examined the effects of elevating SOX2 on their proliferation, both in vitro and in vivo. In addition, we examined how elevating SOX2 influences their expression of cyclins, cyclin-dependent kinases (CDKs), and p27Kip1. Results Elevating SOX2 in diverse tumor cell types led to growth inhibition in vitro. Significantly, elevating SOX2 in vivo in pancreatic ductal adenocarcinoma, medulloblastoma, and prostate cancer cells induced a reversible state of tumor growth arrest. In all three tumor types, elevation of SOX2 in vivo quickly halted tumor growth. Remarkably, tumor growth resumed rapidly when SOX2 returned to endogenous levels. We also determined that elevation of SOX2 in six tumor cell lines decreased the levels of cyclins and CDKs that control each phase of the cell cycle, while upregulating p27Kip1. Conclusions Our findings indicate that elevating SOX2 above endogenous levels in a diverse set of tumor cell types leads to growth inhibition both in vitro and in vivo. Moreover, our findings indicate that SOX2 can function as a master regulator by controlling the expression of a broad spectrum of cell cycle machinery. Importantly, our SOX2-inducible tumor studies provide a novel model system for investigating the molecular mechanisms by which elevated levels of SOX2 restrict cell proliferation and tumor growth.

scholarly journals Combinations of TLR Ligands: A Promising Approach in Cancer Immunotherapy

2013 ◽  
Vol 2013 ◽  
pp. 1-14 ◽  
Author(s):  
Saskia Stier ◽  
Claudia Maletzki ◽  
Ulrike Klier ◽  
Michael Linnebacher
Keyword(s):  
Tumor Growth ◽  
Tumor Cells ◽  
Cell Lines ◽  
Immune Cells ◽  
Human Lymphocytes ◽  
Growth Control ◽  
Poly I:C ◽  
The Impact

Toll-like receptors (TLRs), a family of pattern recognition receptors recognizing molecules expressed by pathogens, are typically expressed by immune cells. However, several recent studies revealed functional TLR expression also on tumor cells. Their expression is a two-sided coin for tumor cells. Not only tumor-promoting effects of TLR ligands are described but also direct oncopathic and immunostimulatory effects. To clarify TLRs’ role in colorectal cancer (CRC), we tested the impact of the TLR ligands LPS, Poly I:C, R848, and Taxol on primary human CRC cell lines (HROC40, HROC60, and HROC69)in vitroandin vivo(CT26). Taxol, not only a potent tumor-apoptosis-inducing, but also TLR4-activating chemotherapeutic compound, inhibited growth and viability of all cell lines, whereas the remaining TLR ligands had only marginal effects (R848 > LPS > Poly I:C). Combinations of the substances here did not improve the results, whereas antitumoral effects were dramatically boosted when human lymphocytes were added. Here, combining the TLR ligands often diminished antitumoral effects.In vivo, best tumor growth control was achieved by the combination of Taxol and R848. However, when combined with LPS, Taxol accelerated tumor growth. These data generally prove the potential of TLR ligands to control tumor growth and activate immune cells, but they also demonstrate the importance of choosing the right combinations.

scholarly journals Cytotoxic effect of Montivipera bornmuelleri’s venom on cancer cell lines: in vitro and in vivo studies

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9909
Author(s):  
Carol Haddoub ◽  
Mohamad Rima ◽  
Sandrine Heurtebise ◽  
Myriam Lawand ◽  
Dania Jundi ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cell Lines ◽  
Cytotoxic Effect ◽  
In Vivo Studies ◽  
Dependent Manner ◽  
In Vivo Testing ◽  
Murine Fibrosarcoma ◽  
Dose Dependent

Background Montivipera bornmuelleri’s venom has shown immunomodulation of cytokines release in mice and selective cytotoxicity on cancer cells in a dose-dependent manner, highlighting an anticancer potential. Here, we extend these findings by elucidating the sensitivity of murine B16 skin melanoma and 3-MCA-induced murine fibrosarcoma cell lines to M. bornmuelleri’s venom and its effect on tumor growth in vivo. Methods The toxicity of the venom on B16 and MCA cells was assessed using flow cytometry and xCELLigence assays. For in vivo testing, tumor growth was followed in mice after intratumoral venom injection. Results The venom toxicity showed a dose-dependent cell death on both B16 and MCA cells. Interestingly, overexpression of ovalbumin increased the sensitivity of the cells to the venom. However, the venom was not able to eradicate induced-tumor growth when injected at 100 µg/kg. Our study demonstrates a cytotoxic effect of M. bornmuelleri’s venom in vitro which, however, does not translate to an anticancer action in vivo.

scholarly journals Long Non-coding RNA PTPRG-AS1 Promotes Cell Tumorigenicity in Epithelial Ovarian Cancer by Decoying microRNA-545-3p and Consequently Enhancing HDAC4 Expression

2020 ◽  
Author(s):  
Juanjuan Shi ◽  
Xijian Xu ◽  
Dan Zhang ◽  
Jiuyan Zhang ◽  
Hui Yang ◽  
...  
Keyword(s):  
Ovarian Cancer ◽  
Cell Proliferation ◽  
Tumor Growth ◽  
Epithelial Ovarian Cancer ◽  
Cell Lines ◽  
Luciferase Reporter ◽  
Non Coding Rna ◽  
Long Non Coding Rna

Abstract Background: Long non-coding RNA PTPRG antisense RNA 1 (PTPRG-AS1) deregulation has been reported in various human malignancies and identified as an important modulator of cancer development. Few reports have focused on the detailed role of PTPRG-AS1 in epithelial ovarian cancer (EOC) and its underlying mechanism. This study aimed to determine the physiological function of PTPRG-AS1 in EOC. A series of experiments were also done to identify the mechanisms through which PTPRG-AS1 exerts its function in EOC.Methods: Reverse transcription-quantitative polymerase chain reaction was used to determine PTPRG-AS1 expression in EOC tissues and cell lines. PTPRG-AS1 was silenced in EOC cells and studied with respect to cell proliferation, apoptosis, migration, invasion in vitro, and tumor growth in vivo. The putative miRNAs that target PTPRG-AS1 were predicted using bioinformatics analysis and further confirmed in luciferase reporter and RNA immunoprecipitation assays.Results: Our data verified the upregulation of PTPRG-AS1 in EOC tissues and cell lines. High PTPRG-AS1 expression was associated with shorter overall survival in patients with EOC. Functionally, EOC cell proliferation, migration, invasion in vitro and tumor growth in vivo were suppressed by PTPRG-AS1 silencing. In contrast, cell apoptosis was promoted by loss of PTPRG-AS1. For the mechanism part, PTPRG-AS1 could serve as a competing endogenous RNA in EOC cells by decoying microRNA-545-3p (miR-545-3p), thereby elevating histone deacetylase 4 (HDAC4) expression. Furthermore, rescue experiments revealed that PTPRG-AS1 knockdown-mediated effects on EOC cells were, in part, counteracted by the inhibition of miR-545-3p or restoration of HDAC4.Conclusions: PTPRG-AS1 functioned as an oncogenic lncRNA that aggravated the malignancy of EOC through the miR-545-3p/HDAC4 ceRNA network. Thus, targeting the PTPRG-AS1/miR-545-3p/HDAC4 pathway may be a novel strategy for EOC anticancer therapy.

scholarly journals Development of Novel Chalcone Analogs as Potential Multi-Targeted Therapies for Castration-Resistant Prostate Cancer

2021 ◽  
Author(s):  
Ola Hussein ◽  
Feras Alali ◽  
Ala‐Eddin Al Mustafa ◽  
Ashraf Khalil
Keyword(s):  
Prostate Cancer ◽  
Cell Lines ◽  
In Vivo Studies ◽  
Treatment Modalities ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Biological Studies ◽  
In Silico Admet

Prostate cancer (PCa) is the second most frequently diagnosed malignancy, as well as a leading cause of cancer-related mortality in men globally. Despite the initial response to hormonal targeted therapy, the majority of patients ultimately progress to a lethal form of the disease, castration-resistant prostate cancer (CRPC). Therefore, the objective of this study was to discover and develop novel treatment modalities for CRPC. Chalcones are among the highly attractive scaffolds being investigated for their antitumor activities. A library of 26 chalcone analogs were designed, synthesized and evaluated as potential therapies for CRPC. The design was guided by in-silico ADMET prediction in which analogs with favorable drug-likeness properties were prioritized. The new compounds were synthesized, purified and characterized by extensive structural elucidation studies. The compounds in vitro cytotoxicity was evaluated against two androgen receptor (AR)-negative prostate cancer cell lines (PC3 and DU145). Among the tested compounds, pyridine containing analogs (13, 15 and 16) showed potent antiproliferative activities with IC50 values ranging between 4.32-6.47 µM against PC3 and DU145 cell lines. Detailed biological studies of the lead molecule 16 revealed that it can significantly induce apoptosis through upregulation of Bax and downregulation of Bcl-2. In addition, compound 16 potently inhibited colony formation and reduced cell migration of AR-negative PCa cell lines (PC3 and DU145). The molecular pathway analysis showed that the anticancer activity of compound 16 is associated with blocking of ERK1/2 and Akt activities. Furthermore, compound 16 inhibited angiogenesis in the chick chorioallantoic membrane (CAM) model as compared to control. Structure-activity relationship study revealed that the cytotoxicity could dramatically improve via changing the methoxylation pattern by more than 2-folds (IC50 << 2.5 μM). These results indicate that pyridine-based chalcones could serve as promising lead molecules for the treatment of CRPC; thus, further in vitro and in vivo studies are warranted.

Studies of pemetrexed and gemcitabine, alone and in combinations, in human lung cancer models

2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 17114-17114 ◽  
Author(s):  
D. C. Chan ◽  
V. J. Chen ◽  
Z. Zhang ◽  
B. Helfrich ◽  
F. R. Hirsch ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cell Lines ◽  
In Vivo Studies ◽  
Human Lung Cancer ◽  
Dependent Manner ◽  
Antitumor Effects ◽  
Nude Rats ◽  
Combination Regimens

17114 Background: Gemcitabine (GEM) is a deoxycytidine analog that inhibits DNA synthesis. Pemetrexed (ALIMTA, PEM) is a novel antifolate inhibiting multiple enzymes targets, including thymidylate synthase (TS). This study aimed at evaluating the antitumor effects of these antimetabolites against NSCLC and SCLC tumor models. Methods: In vitro growth inhibition (IC50) studies were done by 6-days MTT assays against a panel of 20 NSCLC and 17 SCLC cell lines. In vivo studies used only NSCLC H2122 tumor line, implanted either subcutaneously in athymic nude mice or orthotopically in athymic nude rats. Drugs were given via the ip route at the designated schedules. Results: Against NSCLC and SCLC cell lines, the averaged IC50s of GEM were 0.015 ± 0.008 μM and 0.055 ± 0.04 μM respectively. The corresponding averaged IC50s for PEM were 0.65 ± 0.2 μM and 0.091±0.018 μM respectively. When H2122 tumors reached 50–100mg, mice were treated with 10 daily doses of PEM at 100, 200 and 300 mg/kg, or three doses of GEM every 4 days at 30, 60 and 120 mg/kg. PEM delayed tumor growth by 12 to 18 days, and GEM delayed by 10 to 14 days, relative to vehicle control. Results of three combination regimens with GEM (30 mg/kg) and PEM (100 mg/kg) were: (1) GEM → PEM gave intermediate activities between the two single agents, but was toxic to animals; (2) PEM and GEM given concurrently were more active than single agents alone and delayed tumor growth by 12 days with some toxic side effects; (3) PEM → GEM was better than the single agents alone, and delayed tumor growth by ∼14 days without toxicity. Athymic nude rats bearing orthotopic H2122 tumors given PEM daily at 50, 100 and 200 mg/kg for 21 days had significantly prolonged survival, but not in a dose-dependent manner. PEM at 50 mg/kg was more effective than doses at 100 or 200 mg/kg. GEM was toxic to nude rats due to poor plasma deamination of GEM. Conclusions: In vitro, PEM was more potent against SCLC than NSCLC cell lines, but GEM had similar activities against all lung lines tested. Studies of H2122 xenografts in rodent supported PEM → GEM as the preferred sequence for the combined administration of these two drugs. [Table: see text]

Anti-Myeloma Activity by the Combination of the JAK2 Inhibitor Ruxolitinib with Lenalidomide and Corticosteroids

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 2114-2114 ◽  
Author(s):  
Haiming Chen ◽  
Eric Sanchez ◽  
Mingjie Li ◽  
Cathy Wang ◽  
Abby Gillespie ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cell Viability ◽  
Tumor Cells ◽  
Cell Lines ◽  
Scid Mice ◽  
M Protein ◽  
Cytotoxic Effects ◽  
Jak2 Inhibitor

Abstract Introduction: The JAK2 inhibitor ruxolitinib (RUX) is an inhibitor of the Janus kinase family of protein tyrosine kinases (JAKs) that is effective for the treatment of myeloproliferative diseases. Immunomodulatory drugs (IMiDs) including lenalidomide (LEN) and corticosteroids have shown efficacy for the treatment of multiple myeloma (MM). The JAK-STAT signaling pathway plays key roles in the growth and survival of malignant plasma cells in MM. In this study, we evaluated the preclinical anti-MM effects of RUX in combination with LEN and corticosteroids, both in vitro and in vivo, and in a patient with MM and polycythemia rubra vera (PRV). Methods: The human MM cell lines U266, RPMI8226 and MM1S cells were derived from ATCC. Primary MM tumor cells were isolated from MM patients’ bone marrow aspirates. The cells were seeded at105 cells/100ul/well in 96-well plates and incubated for 24 h in the presence of vehicle, RUX, LEN or dexamethasone (DEX) alone, RUX + LEN, RUX + DEX, or all three drugs together for 48 h. Cell viability was quantified using the MTS cell proliferation assay. In vitro, synergy between ruxolitinib and lenalidomide or dexamethasone was assessed using the median effect method of Chou and Talalay. For the in vivo studies, the human myeloma tumors (LAGκ-1A or LAGκ-2) were surgically implanted into the left superficial gluteal muscle of anaesthetized naive SCID mice. Mice were blindly assigned to one of the experimental groups, and treatment was initiated 7–21 d after tumor implantation. LEN was administered via oral gavage daily (30 mg/kg). RUX (3 mg/kg) was given via intraperitoneal (IP) injection twice daily. Dexamethasone was administered daily (1.5mg/kg) via IP injection. An 88 year old MM patient with PRV who developed MM on RUX alone and then progressed on LEN+DEX was treated with the combination of all three drugs. Results: In vitro, RUX induced concentration-dependent inhibition of viability in all three MM cell lines (U266, RPMI8226 and MM1S) at RUX 50 mM and inhibition of primary MM tumor cells at a higher concentration (100 mM). In contrast, RUX had negligible cytotoxic effects on normal peripheral blood mononuclear cells (PBMCs). We next examined cell viability in the presence of RUX plus LEN or DEX. First, U266 cells were incubated with a fixed concentration of LEN (30 mM) or DEX (40 mM) with increasing concentrations of RUX (0.1–100 mM) for 48 h. At RUX 50 mM, the cytotoxic effects of LEN were enhanced and at RUX 1 mM, the anti-myeloma effect of DEX was increased. Moreover, the cytotoxic effects of RUX, LEN and DEX were greater than RUX in combination with either LEN or DEX in U266 cells. Similar results were obtained using the RPMI8226 and MM1S cell lines as well as primary MM tumor cells. Next, we evaluated RUX in combination with lenalidomide and dexamethasone in vivo using SCID mice bearing either the human LAGκ-1A or LAGκ-2 MM xenografts. RUX (3mg/kg), LEN (15mg/kg) or DEX (1mg/kg) alone did not inhibit tumor growth in either mice bearing LAGκ-1A or LAGκ-2. In contrast, the combination of RUX with DEX but not LEN slightly decreased tumor volume. However, the combination of all three drugs at the same doses showed a marked reduction of tumor size and delay of tumor growth in both human MM xenograft models. In addition, a patient with MM and PRV experienced sustained and ongoing reductions in his serum M-protein, IgG, and 24-urine M-protein with achievement of a partial response on low doses of RUX (2.5 mg twice daily), LEN (2.5 mg daily), and methylprednisolone (20 mg daily) that has been ongoing for more than 12 months after developing MM on RUX alone and then progressing on the combination of LEN and methylprednisolone. Conclusion: This study illustrates that the combination of the JAK2 inhibitor RUX, LEN and corticosteroids shows both preclinical and promising clinical results for the treatment of MM. Disclosures No relevant conflicts of interest to declare.

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