Ruxolitinib: long-term management of patients with myelofibrosis and future directions in the treatment of myeloproliferative neoplasms

[Regulation of Ruxolitinib on matrix metalloproteinase in JAK2V617F positive myeloroliferative neoplasms cells]

Objective: To investigate the regulation of JAK2 tyrosine kinase inhibitor ruxolitinib on extracellular matrix metalloproteinase (MMP in JAK2V617F positive myeloproliferative neoplasms (MPN) cells. Methods: ①Forty cases of newly diagnosed JAK2V617F positive MPN patients and 15 healthy volunteers as control in Baoding No.1 Hospital between January 2012 and December 2015 were enrolled in this study. JAK2V617F/JAK2 ratio was detected by real-time-PCR; the expression levels of phosphorylation protein tyrosine kinase 2 (p-JAK2) , MMP-2 and MMP-9 in pathological tissues of bone marrow were detected by immunohistochemistry. The bone marrow cells of JAK2V617F positive MPN patients were treated with ruxolitinib, then the migration ability and MMP-2, MMP-9 gene and protein expression levels were detected. ②The human erythroleukemia cell line HEL cells were treated with different concentrations of ruxolitinib (0, 50, 100, 250, 500, 1 000 nmol/L) . The cell viability was detected by CCK-8 test; cell migration ability was tested by transwell chambers. The mRNA expression levels of JAK2, MMP-2 and MMP-9 were detected by real-time-PCR. The protein expression levels of p-JAK2, MMP-2 and MMP-9 were detected by Western blot. Results: ①The expression levels of p-JAK2, MMP-2 and MMP-9 in the newly diagnosed group were significantly higher than control group respectively [ (78.56±24.55) % vs (41.59±17.29) %, P<0.05; (48.25±18.74) % vs (22.79±13.89) %, P<0.05; (53.29±19.28) % vs (15.56±14.96) %, P<0.05]. Spearman correlation analysis showed the positive correlation of MMP-2 and MMP-9 protein expression levels with JAK2V617F mutation (r=0.526, P=0.001; r=0.543, P=0.001) . ②The proliferation of HEL cells was inhibited by different concentrations of ruxolitinib in time and dose dependent manner. ③Cell migration test showed the number of cells leaked to the low chamber in MPN patients bone marrow cells and HEL cells treated with 5 nmol/L of ruxolitinib group were significantly lower than that without ruxolitinib treatment after 24 h [ (154.7±27.5) vs (320.3±67.3) , t=13.47, P<0.05; (70.7±10.5) vs (135.3±16.7) , t=13.89, P<0.05]. The mRNA and protein expression levels of JAK2, MMP-2 and MMP-9 decreased with the increased concentration of ruxolitinib. Conclusion: Ruxolitinib inhibits MPN cell migration and expression of MMP-2 and MMP-9 via JAK2 signal pathway.

Angiogenesis in JAK2 V617F positive myeloproliferative neoplasms and ruxolitinib decrease VEGF, HIF-1 enesis in JAK2 V617F positive cells

Angiogenesis and JAK2 V617F mutation are common in BCR-ABL1 negative myeloproliferative neoplasms (MPNs). Ruxolitinib, a JAK inhibitor, is an effective treatment for some MPNs. However, the relationship between angiogenesis and JAK2 V617F and the effects of ruxolitinib on angiogenesis are still unknown. Here, we observed the correlation of JAK2 V617F mutation burden with VEGF, HIF-1a and microvascular density (MVD) in MPNs. We investigate the effect of ruxolitinib on the expression of VEGF and HIF-1α in JAK2 V617F positive cells. We found the expression levels of p-JAK2, VEGF, HIF-1a and MVD in the newly diagnosed MPNs were significantly increased and were related to the JAK2 V617F burden. Ruxolitinib can inhibit p-JAK2, VEGF, HIF-1a expression and suppress blood vessels' formation in chick embryo choriallantoic membrane. Our findings indicated that angiogenesis is related to JAK2 V617F burden and ruxolitinib could decrease VEGF and HIF-1a expression in JAK2 V617F positive cells.

Changing incidence of myeloproliferative neoplasms: trends and subgroup risk profiles in the USA, 1973-2011

PURPOSE

Recent diagnostic and cancer reporting changes influencing myeloproliferative neoplasms (MPNs) encourage the assessment of trends and examination of the recently identified MPN subtypes: polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), across the age continuum by race and ethnicity.

METHODS

Surveillance, Epidemiology, and End Results data provided MPN incidence data since 1973 and MPN subtype data since 2001. Joinpoint regression estimated annual percent changes. Poisson regression estimated risk ratios.

RESULTS

The 2005 JAK2 V617F discovery and the 2008 WHO diagnostic guideline for the JAK2 V617F mutation coincide with a 31 % increase in ET and a 21 % decrease in PV incidence rates. We found that younger women had a 13-33 % higher ET risk and that women under the age of 34 had a 58 % higher PMF risk, relative to men. Blacks, aged 35-49 with a higher ET risk, also had a 69 % higher PMF risk relative to whites.

CONCLUSION

Demographic characteristic of ET and PMF patients may be useful for improving risk prediction and informing clinical screening and treatment strategies. Changing guidelines, new discoveries, and in-depth analysis of a large population-based study have implications for accurately identifying incident cases of MPNs, MPN subgroups, and health resource planning.

Transient blocking of NK cell function with small molecule inhibitors for helper dependant adenoviral vector-mediated gene delivery

One major challenge in gene therapy is the host immune responses against viral vectors. Previous studies indicate the involvement of NK cells in stunted gene expression in viral vector mediated gene therapy. To understand the problem of the immune responses, we have developed an in-vitro co-culture system with human NK cell line, macrophages and airway epithelial cells. We showed that small molecule blockers, CAPE and ruxolitinib, for NF-κB and JAK-STAT pathways, respectively, significantly inhibited cytokine secretion by macrophages. When NK cells are co-cultured with helper-dependent adenoviral (HD-Ad) vector activated macrophages, IFN-γ cytokine expression by NK cells increased significantly, which was inhibited effectively by ruxolitinib and CAPE, and there was an additive effect when both inhibitors were used. We demonstrated that NK cells activated by cytokines produced by HD-Ad-activated macrophages kill HD-Ad vector transduced bronchial epithelial cells. This cell killing activity was significantly reduced by CAPE and ruxolitinib. Combination of these two inhibitors had an additive effect on inhibiting NK cell mediate killing of gene transduced cells. Transient inhibition of NK cell response at its peak may enhance sustained gene expression. Our data suggest that combination of CAPE and ruxolitinib may help in protecting gene transduced airway epithelial cells to prolong transgene expression.