Chloroquine enhances the efficacy of chemotherapy drugs against acute myeloid leukemia by inactivating the autophagy pathway.

Current therapy for acute myeloid leukemia (AML) is largely hindered by the development of drug resistance of commonly used chemotherapy drugs, including cytarabine, daunorubicin, and idarubicin. In this study, we investigated the molecular mechanisms underlying the chemotherapy drug resistance and potential strategy to improve the efficacy of these drugs against AML. By analyzing data from ex vivo drug-response and multi-omics profiling public data for AML, we identified autophagy activation as a potential target in chemotherapy-resistant patients. In THP-1 and MV-4-11 cell lines, knockdown of autophagy-regulated genes ATG5 or MAP1LC3B significantly enhanced AML cell sensitivity to the chemotherapy drugs cytarabine, daunorubicin, and idarubicin. In silico screening, we found that chloroquine phosphate mimicked autophagy inactivation. We showed that chloroquine phosphate dose-dependently down-regulated the autophagy pathway in MV-4-11 cells. Furthermore, chloroquine phosphate exerted a synergistic antitumor effect with the chemotherapy drugs in vitro and in vivo. These results highlight autophagy activation as a drug resistance mechanism and the combination therapy of chloroquine phosphate and chemotherapy drugs can enhance anti-AML efficacy.

Downregulation of c-Myc expression confers sensitivity to CHK1 inhibitors in hematologic malignancies.

Checkpoint kinase 1 inhibitors (CHK1i) have shown impressive single-agent efficacy in treatment of certain tumors, as monotherapy or potentiators of chemotherapy in clinical trials, but the sensitive tumor types and downstream effectors to dictate the therapeutic responses to CHK1i remains unclear. In this study we first analyzed GDSC (Genomics of Drug Sensitivity in Cancer) and DepMap database and disclosed that hematologic malignancies (HMs) were relatively sensitive to CHK1i or CHK1 knockdown. This notion was confirmed by examining PY34, a new and potent in-house selective CHK1i, which exhibited potent anti-HM effect in vitro and in vivo, as single agent. We demonstrated that the downregulation of c-Myc and its signaling pathway was the common transcriptomic profiling response of sensitive HM cell lines to PY34, whereas overexpressing c-Myc could partially rescue the anticancer effect of PY34. Strikingly, we revealed the significant correlations between downregulation of c-Myc and cell sensitivity to PY34 in 17 HM cell lines and 39 patient-derived cell (PDC) samples. Thus, our results demonstrate that HMs are more sensitive to CHK1i than solid tumors, and c-Myc downregulation could represent the CHK1i efficacy in HMs.

Activation of unfolded protein response overcomes Ibrutinib resistance in diffuse large B-cell lymphoma.

Diffuse large B-cell lymphoma (DLBCL) is the most widespread type of non-Hodgkin lymphoma (NHL). As the most aggressive form of the DLBCL, the activated B-cell-like (ABC) subtype is often resistant to standard chemotherapies. Bruton's tyrosine kinase (BTK) inhibitor ibrutinib provides a potential therapeutic approach for the DLBCL but fails to improve the outcome in the phase III trial. In the current study, we investigated the molecular mechanisms underlying ibrutinib resistance and explored new combination therapy with ibrutinib. We generated an ibrutinib-resistant ABC-DLBCL cell line (OCI-ly10-IR) through continuous exposure to ibrutinib. Transcriptome analysis of the parental and ibrutinib-resistant cell lines revealed that the ibrutinib-resistant cells had significantly lower expression of the unfolded protein response (UPR) marker genes. Overexpression of one UPR branch-XBP1s greatly potentiated ibrutinib-induced apoptosis in both sensitive and resistant cells. The UPR inhibitor tauroursodeoxycholic acid (TUDCA) partially reduced the apoptotic rate induced by the ibrutinib in sensitive cells. The UPR activator 2-deoxy-D-glucose (2-DG) in combination with the ibrutinib triggered even greater cell growth inhibition, apoptosis, and stronger calcium (Ca2+) flux inhibition than either of the agents alone. A combination treatment of ibrutinib (15 mg·kg-1·d-1, po.) and 2-DG (500 mg/kg, po, b.i.d.) synergistically retarded tumor growth in NOD/SCID mice bearing OCI-ly10-IR xenograft. In addition, ibrutinib induced the UPR in the sensitive cell lines but not in the resistant cell lines of the DLBCL. There was also a combined synergistic effect in the primary resistant DLBCL cell lines. Overall, our results suggest that targeting the UPR could be a potential combination strategy to overcome ibrutinib resistance in the DLBCL.

Microenvironment-Responsive Small-Molecule Probe for Pulmonary Fibrosis Detection.

Pulmonary fibrosis (PF) is a fatal disease with increasing prevalence. Nonradioactive and noninvasive diagnosis of PF at an early stage can improve the prognosis but represents a daunting challenge. Up-regulation of nitric oxide (NO) is a typical microenvironmental feature of PF. Here, we report a small-molecule probe, PNO1, that can fluorogenically sense this microenvironmental feature for PF diagnosis. We demonstrate that PNO1 fluorescence is 6-fold higher in PF-diseased mice lungs than in normal-control groups. In addition to this in vivo result, PNO1 can also be applied in vitro to detect PF-diseased cells and ex vivo to detect PF-diseased tissues from clinical patients. These results highlight PNO1 as a complement to the traditional immunostaining-based methods for PF detection to facilitate quick screening for anti-PF drug candidates.

[Anti-inflammatory effect and mechanism of artemisinin and dihydroartemisinin].

OBJECTIVE: To study and compare the anti-inflammatory effect and molecular mechanism of artemisinin and dihydroartemisinin. METHOD: Mouse mononuclear macrophage RAW264.7 cells were stimulated to release inflammatory mediators such as TNF-alpha, IL-6 and NO, in order to assess the drugs' inhibitory effect on macrophage's release of above inflammatory mediators. The levels of TNF-alpha and IL-6 were determined by ELISA and the cytotoxicity was determined by MTT method. The protein expression of iNOS, COX-2 and beta-actin were tested by Western blot. The enzymatic activity of COX-2 was determined by colorimetric method. RESULT: Dihydroartemisinin significantly inhibited LPS-induced release of TNF-alpha, IL-6 and NO from RAW264.7 in mice with the concentration range of 12.5 - 100 micromol x L(-1), and showed good dose dependence. Artemisinin only inhibited the IL-6 release to a certain extent. CONCLUSION: Dihydroartemisinin inhibits macrophages from releasing inflammatory factors TNF-alpha and IL-6 and inflammatory mediators NO by down-regulating iNOS protein. Artemisinin may help dihydroartemisinin to show its anti-inflammatory effect through metabolism.

Design, synthesis and biological evaluation of the thioether-containing lenalidomide analogs with anti-proliferative activities.

Lenalidomide and its analogs have exhibited extensive anti-tumor, anti-inflammatory and immunomodulatory properties in pharmaceutical research. In this work, a series of novel thioether-containing lenalidomide analogs were designed and synthesized for biological evaluation. Lenalidomide showed significant anti-proliferative activity against the MM.1S cell line (IC50 = 50 nM) while it displayed no anti-proliferative activity against other treated tumor cell lines. Compared with lenalidomide, compound 3j exhibited preferable anti-proliferative activity against the MM.1S (IC50 = 1.1 nM), Mino (IC50 = 2.3 nM) and RPMI 8226 cell lines (IC50 = 5.5 nM). In addition, compound 3j displayed selective anti-proliferative activity against several tumor cell lines, including various B-NHL, MM and AML cell lines, and showed no cytotoxicity on the normal human cell line PBMC, suggesting a good safety profile. Following oral administration, compound 3j achieved a Cmax of 283 ng/mL at 0.83 h, and had a higher relative oral bioavailability value (F = 39.2%) than that of CC-220 (F = 22.8%), but its oral exposure in vivo was somewhat low (AUC = 755 h ng/mL). Furthermore, it was found that oral administration of compound 3j at dosages of 60 mg/kg could delay RPMI 8226 tumor growth in the female CB-17 SCID mice. The current work confirmed that installing thioether moiety at the 4-position of isoindolinone is an effective strategy for identifying new promising lenalidomide analogs with anti-tumor activities in preclinical study.