miR-221对慢性粒细胞白血病K562细胞增殖和凋亡的影响及其作用机制

目的：探讨下调miR-221 对慢性粒细胞白血病（CML）K562 细胞增殖和凋亡的影响及其相关的调控机制。方法：将K562 细胞分为对照组、miRNA阴性对照（miR-NC）组、miR-221 inhibitor 组、miR-221 inhibitor+阴性对照siRNA（NC siRNA）组和miR-221 inhibitor+SOCS3 siRNA 组。其中,对照组细胞不进行另外处理;miR-NC 组和miR-221 inhibitor 组分别采用miR-NC 和miR-221 inhibitor 转染至细胞;miR-221 inhibitor+NC siRNA 组和miR-221 inhibitor+SOCS3 siRNA 组采用已稳定转染miR-221 inhibitor的细胞再分别转染NC siRNA 和SOCS3 siRNA。用qPCR鉴定miR-221 inhibitor 的转染效率,CCK-8 法检测各组细胞的增殖活性,Annexin V-FITC/PI 双染色流式术检测各组细胞的凋亡水平,WB实验检测各组细胞的SOCS3、p-JAK1、p-JAK2、p-STAT3和survivin 的蛋白表达水平。结果：与对照组比较,miR-221 inhibitor 组细胞内miR-221 的表达显著下调（P<0.01）,细胞增殖活性在转染后48、72 h 时明显降低（P<0.05 或P<0.01）,凋亡细胞数量明显增加（P<0.01）,细胞内SOCS3 的表达水平明显增加（P<0.01）,而p-JAK1、p-JAK2、p-STAT3 和survivin 的表达水平均明显降低（均P<0.01）。与miR-221 inhibitor 组比较,miR-221 inhibitor+SOCS3 siRNA组细胞增殖活性在转染后24、48 和72 h 时明显增加（P<0.05 或P<0.01）,凋亡细胞数量明显减少（P<0.01）,细胞内p-JAK1、p-JAK2、p-STAT3 和survivin 的表达水平均明显增加（均P<0.01）。结论：下调miR-221 可能通过上调SOCS3 表达抑制JAK-STAT3 信号通路,从而抑制K562 细胞增殖并促进其凋亡。     

The medicinal use of realgar (As₄S₄) and its recent development as an anticancer agent

Ethnopharmacological relevance

Arsenicals have been known as poisons and paradoxically as therapeutic agents. In the early 1970s, Chinese physicians from Harbin revived the medicinal use of arsenicals as anticancer agents. Notable success was observed in the treatment of acute promyelocytic leukemia (APL) with arsenic trioxide (ATO). The FDA approved ATO injection in the year 2000 for the treatment of APL. In contrast, the clinical use of the other arsenical, realgar (As₄S₄), is currently much less established, though it has also long been used in medical history. According to ancient medical records and recent findings in clinical trials, realgar was found as effective as ATO, but with relatively good oral safety profiles even on chronic administration. These give realgar an advantage over ATO in maintenance treatment. Though there is increasing understanding on the mechanisms of action and metabolic profiles of ATO, similar aspects of realgar are unclear to date.

Materials and methods

We outline the use of realgar in traditional medicines, especially in traditional Chinese medicines (TCM) from ancient times to present. The clinical and experimental observations on realgar as a therapeutic agent are described with an emphasis on those findings that may imply the rationale and future directions of realgar as a potential anticancer drug candidate.

Results

There is an increasing understanding in the mechanisms of action of realgar as an antileukemic agent. However, there is still sparse information on its metabolism and toxicity profiles.

Conclusions

Realgar is poorly soluble in water. Recently, several types of realgar nanoparticles (NPs) have been developed. Some of these realgar NPs also possess the unique optical properties of quantum dots. The activities and bioavailability of realgar NPs are much influenced by their sizes, making realgar an interesting biomedical and pharmaceutical research candidate.     

Hydroxycitric Acid Inhibits Chronic Myelogenous Leukemia Growth through Activation of AMPK and mTOR Pathway

Metabolic regulation of cancer cell growth via AMP-activated protein kinase (AMPK) activation is a widely studied strategy for cancer treatment, including leukemias. Recent notions that naturally occurring compounds might have AMPK activity led to the search for nutraceuticals with potential AMPK-stimulating activity. We found that hydroxycitric acid (HCA), a natural, safe bioactive from the plant Garcinia gummi-gutta (cambogia), has potent AMPK activity in chronic myelogenous leukemia (CML) cell line K562. HCA is a known competitive inhibitor of ATP citrate lyase (ACLY) and is widely used as a weight loss inducer. We found that HCA was able to inhibit the growth of K562 cells in in vitro and in vivo xenograft models. At the mechanistic level, we identified a direct interaction between AMPK and ACLY that seems to be sensitive to HCA treatment. Additionally, HCA treatment resulted in the co-activation of AMPK and the mammalian target of rapamycin (mTOR) pathways. Moreover, we found an enhanced unfolded protein response as observed by activation of the eIF2α/ATF4 pathway that could explain the induction of cell cycle arrest at the G2/M phase and DNA fragmentation upon HCA treatment in K562 cells. Overall, these findings suggest HCA as a nutraceutical approach for the treatment of CMLs.     

Efficacy and safety of nilotinib in chronic myeloid leukaemia patients who failed to achieve a treatment-free remission period after imatinib discontinuation: Results of the French Nilo post-STIM study

Molecular recurrence (MRec) occurs in about half of all patients with chronic myeloid leukaemia (CML) who discontinue tyrosine kinase inhibitors (TKI) in sustained deep molecular response. A second TKI discontinuation has been attempted in some patients who regain the discontinuation criteria after resuming treatment. Nilotinib treatment affords faster and deeper molecular responses than imatinib as first-line therapy. We prospectively evaluated the efficacy and safety of nilotinib (300 mg twice daily) in chronic-phase CML patients who experienced MRec, after imatinib discontinuation and analysed the probability of TFR after a new attempt in patients treated for 2 years with sustained MR^4.5 for at least 1 year. A total of 31 patients were included in the study between 2013 and 2018. Seven (23%) patients experienced serious adverse events after a median of 2 months of nilotinib treatment leading to discontinuation of treatment. One patient was excluded from the study for convenience. Among the 23 patients treated for 2 years with nilotinib, 22 maintained their molecular response for at least 1 year (median: 22 months) and stopped nilotinib. The TFR rates at 24 and 48 months after nilotinib discontinuation were 59.1% (95% confidence interval [CI]: 41.7%–83.7%) and 42.1% (95% CI: 25%–71%) respectively (NCT #01774630).     

慢性粒细胞白血病骨髓体外净化的实验研究

目的　探讨白细胞介素、干扰素 α2 a、bcr- abl反义寡核苷酸对慢性粒细胞白血病骨髓体外净化效果。方法　采用体外克隆形成培养技术 ,分别用白细胞介素、干扰素 α2 a、bcr- abl反义寡核苷酸不同的组合方案 ,体外净化 5例慢性粒细胞白血病 (CML)骨髓。结果　联用 IL- 2、IFN- α2 a(各 80 0 u/ m l)、bcr- abl AS- ODN(30 μg/ ml)方案 ,对白血病细胞克隆形成单位 (L- CFU)抑制作用有显著差异 (P<0 .0 1) ,而相同条件下 ,GM- CFU及 L- CFU的集落存活率分别为 2 6 .91%和 3.49% (P<0 .0 1)。结论　联用 IL- 2、IFN- α2 a(各 80 0 u/ m l)、bcr- abl AS- ODN(30 μg/ml)方案 ,选择性体外净化慢性粒细胞白血病细胞的效果好 ,可用于临床净化 CML 骨髓     

A Systematic Review on Second Treatment-Free Remission (TFR) Attempt in Chronic Myeloid Leukemia (CML): Can it be Applied in Clinical Practice?

The prognosis and life expectancy of chronic myeloid leukemia (CML) patients have improved significantly with the launch of first tyrosine kinase inhibitor (TKI), imatinib. Maintaining at least one major molecular response in CML patients without the use of TKI is known as treatment-free remission (TFR). The safety of the first TFR (TFR1) effort has been reported by numerous studies. However, some patients relapse during TFR1. A second TFR (TFR2) can be tried again in those patients. This systematic review aims to evaluate individual patient characteristics for a TFR2, factors predicting successful TFR2, monitoring, consequences of the cessation of TKI, and studies about TFR2. We identified 5 studies related TFR2. The results showed that the first failed TKI discontinuation attempt is not an indicator of a second TKI discontinuation failure. TKIs could safely and successfully be discontinued for a second time in chronic phase CML patients despite a TFR1 failure. The most important factors for estimating TFR2 success are the speed of molecular relapse and the TKI-free duration after the first TKI discontinuation attempt. New trends in the management of CML patients are reducing the side effects of treatment, lessening the financial burden, and improving the quality of life of patients as CML has developed into a manageable chronic disease rather than an aggressive cancer. Although there are many studies and guidelines on TFR1, there are few studies on TFR2 and predictive factors. More data is still needed regarding TFR2 attempt in patients with CML.     

Immune modulation in chronic myeloid leukaemia patients treated with nilotinib and interferon-alpha

The addition of interferon to tyrosine kinase inhibitors (TKIs), to improve deep molecular response (DMR) and potentially treatment-free remission (TFR) rates in chronic-phase chronic myeloid leukaemia (CP-CML) patients is under active investigation. However, the immunobiology of this combination is poorly understood. We performed a comprehensive longitudinal assessment of immunological changes in CML patients treated with nilotinib and interferon-alpha (IFN-α) within the ALLG CML11 trial (n = 12) or nilotinib alone (n = 17). We demonstrate that nilotinib+IFN transiently reduced absolute counts of natural killer (NK) cells, compared with nilotinib alone. Furthermore, CD16⁺-cytolytic and CD57⁺CD62L⁻-mature NK cells were transiently reduced during IFN therapy, without affecting NK-cell function. IFN transiently increased cytotoxic T-lymphocyte (CTL) responses to leukaemia-associated antigens (LAAs) proteinase-3, BMI-1 and PRAME; and had no effect on regulatory T cells, or myeloid-derived suppressor cells. Patients on nilotinib+IFN who achieved MR4.5 by 12 months had a significantly higher proportion of NK cells expressing NKp46, NKp30 and NKG2D compared with patients not achieving this milestone. This difference was not observed in the nilotinib-alone group. The addition of IFN to nilotinib drives an increase in NK-activating receptors, CTLs responding to LAAs and results in transient immune modulation, which may influence earlier DMR, and its effect on long-term outcomes warrants further investigation.