A CD36-dependent non-canonical lipid metabolism program promotes immune escape and resistance to hypomethylating agent therapy in AML.

Environmental lipids are essential for fueling tumor energetics, but whether these exogenous lipids transported into cancer cells facilitate immune escape remains unclear. Here, we find that CD36, a transporter for exogenous lipids, promotes acute myeloid leukemia (AML) immune evasion. We show that, separately from its established role in lipid oxidation, CD36 on AML cells senses oxidized low-density lipoprotein (OxLDL) to prime the TLR4-LYN-MYD88-nuclear factor κB (NF-κB) pathway, and exogenous palmitate transfer via CD36 further potentiates this innate immune pathway by supporting ZDHHC6-mediated MYD88 palmitoylation. Subsequently, NF-κB drives the expression of immunosuppressive genes that inhibit anti-tumor T cell responses. Notably, high-fat-diet or hypomethylating agent decitabine treatment boosts the immunosuppressive potential of AML cells by hijacking CD36-dependent innate immune signaling, leading to a dampened therapeutic effect. This work is of translational interest because lipid restriction by US Food and Drug Administration (FDA)-approved lipid-lowering statin drugs improves the efficacy of decitabine therapy by weakening leukemic CD36-mediated immunosuppression.

Once-Weekly 1.6 mg/m2 Bortezomib BCD Regimen in Elderly Patients with Newly Diagnosed Multiple Myeloma Who are Unfit for Standard Dose Chemotherapy.

Bortezomib has shown anti-myeloma effects in combination with alkylating agents, but clinical benefits can be limited by neurotoxicity. There is less information on the efficacy and tolerability of once-weekly 1.6 mg/m2 bortezomib combined with cyclophosphamide and dexamethasone (BCD) regimen in elderly patients with newly diagnosed multiple myeloma who are unfit for standard dose chemotherapy. Here, we report our experience of weekly 1.6 mg/m2 intravenous bortezomib in this group of patients. Between March 2010 and February 2015, we treated 34 newly diagnosed elderly patients with the combination of bortezomib 1.6 mg/m2 intravenously on days 1 and 8; cyclophosphamide 200 mg/m2 intravenously on days 1-4; dexamethasone 20 mg intravenously on days 1-4, and 8-11. Among the 34 patients, 14 (41 %) responded with complete response (CR), 6 (18 %) with very good partial response (VGPR) and 10 (29 %) with partial response (PR). The overall response rates were 88 %. After 2 cycles of treatments, the survival of patients who attained a response of VGPR or CR was significantly longer than those with PR or resistance to BCD, for both progression-free survival (PFS) (21.4 vs. 10.6 months, p = 0.002) and overall survival (OS) (23.0 vs. 16.8 months, p = 0.043). The 2-year PFS and OS were 26.5 and 64.7 % respectively in these elderly multiple myeloma patients in our study. Grade 1/2 neuropathy was observed in 20 % of the cycles while grade 3/4 neuropathy was not observed. No patients withdrew due to neuropathy or other side effects. Once-weekly bortezomib at 1.6 mg/m2 BCD regimen is both effective and safe in elderly patients with newly diagnosed multiple myeloma who are unfit for standard dose chemotherapy.

Leukemia propagating cells rebuild an evolving niche in response to therapy.

Residence of cancer-propagating cells (CPCs) within preferential microenvironmental niches has a major part in evading therapy. However, the nature of niches involved and the mechanisms protecting CPCs remain largely unknown. We addressed these issues in mouse transplantation models of acute lymphoblastic leukemia (ALL). When the engrafted leukemic cells substantially damaged adjacent microenvironment in the bone marrow (BM), after chemotherapy small foci of CPCs were retained, surrounded by sheaths of supporting cells that comprise a protective niche. We investigated patients' BM biopsies and found evidence of a similar process in patients receiving induction therapy. The efficacy of chemotherapy was enhanced by interfering with the niche formation or function. We therefore identified a therapy-induced niche that protects CPCs.

[Correlation between ALIP-like cluster and fibrous proliferation in bone marrow of patients with acute myeloid leukemia in CR phase].

This study was purposed to elucidate the prognostic values of ALIP (abnormal location of immature precursors)-like clusters and fibrous proliferation in bone marrow of AML patients in CR phase and the correlation between them. The bone marrow biopsy sections from 47 AML patients during admitting to relapse or till lost follow-up were examined retrospectively. The 47 patients were divided into pre-relapsed group and non-relapsed group according to relapse or not at end of follow-up. The concentration of ALIP-like cluster and reticulin fiber density (RFD) in sections were compared between the two groups respectively, the prognostic value of these two factors and the underlying relationship between them were estimated by statistical analysis. The results showed that ALIP-like cluster was (3.46 ± 2.71)/mm(2) during CR and RFD was (2.76% ± 1.50%) in pre-relapsed cases, which both were higher than those in non-relapsed cases (P < 0.05). Cases with ALIP-like cluster over 4/mm(2) or with RFD>1.68% showed high relapse rates of 89.5% or 95.2% respectively. RFD were (2.47% ± 2.48%) and (2.44% ± 2.23%) in cases with >4/mm(2) or ≤ 4/mm(2) respectively, there was no statistical significance (P > 0.05) . Meanwhile, the amount of ALIP-like cluster in CR not related with the paired RFD (r = 0.057, P > 0.05). It is concluded that both ALIP-like cluster in CR and RFD are poor prognostic factors for heralding early relapse. However, ALIP-like cluster and RFD show no correlation, and suggest that forming of ALIP not depends on fibrogenesis.

[Influence of pre-ALIP number and its distance from trabeculae on AML relapse].

This study was purposed to detect the abnormal quantity and localization of pre-ALIP in bone marrow of acute myelocytic leukemia patients (AML) during the complete remission (CR) and investigate their correlation with AML relapse. The bone marrow biopsy and prognosis of 62 patients with CR were retrospectively analyzed. The bone marrow was divided into the pre-relapse group and the no-relapse group according to prognosis of patients. In order to clarify the correlation of abnormal quantity and localization of pre-ALIP with AML relapse, the number of single and double-cluster precursor cells and the sum of both were calculated, and their distance from bone trabeculae was surveyed with the computer image segment method. The results showed that the number of pre-ALIP in pre-relapse group (11 ± 11.71/mm(2)) and no-relapse group (8.33 ± 9.17/mm(2)) were more than that in normal control group (5.29 ± 4.00) (P < 0.01). The number of pre-ALIP more than 11/mm(2) was observed in 17 among all AML patients, and out of them 12 patients with pre-ALIP number >11/mm(2) (70.6) were found in the pre-relapse group, which was higher than that in no-relapse group (P < 0.05). While the distance between pre-ALIP and trabeculae [(341.31 ± 266.16) µm] in pre-relapse group showed the tendency of migrating to the intermediate zone of bone trabeculae, compared with that in no-relapse group [(242.41 ± 174.65) µm, P < 0.01]. Moreover, about 77.8 of 18 patients showed the distance of pre-ALIP from trabeculae was more than 341 µm in the pre-relapse group, and significantly higher than that in no-relapse group (P < 0.01). It is concluded that the average number of "pre-ALIP" more than 11/mm(2) or the average distance from trabeculae longer than 341 µm in bone marrow sections during CR may be the indicators for early relapse of AML.

[Characteristics of "pre-ALIP" in bone marrow sections of patients with acute myeloid leukemia].

To detect the characteristics of "pre-ALIP" and to investigate their relevance with the development of acute myeloid leukemia (AML) by computer image procession technology, bone marrow (BM) was collected by aspiration/trephine biopsy from AML patients during the complete remission (CR). BM sections were stained by HGF (haematoxylin-Giemsa-acid fuchsin) and photographed by optical microscope imaging system. 4 kinds of computer image segmentation technologies were compared to select the best one for detecting the localization and quantitation of the precursor cells. Planimetry was combined with morphology to segment bone trabeculae. The number of single and double-cluster precursor cells and their distance from bone trabeculae was detected with Euclidean distance change method in BM images of AML patients, and compared with the normal controls. Moreover, the morphological characteristics of "pre-ALIP" were investigated, and the correlation with the development of AML was analyzed. The results showed that the computer image segmentation method based on morphology could identify the precursor cells and bone trabeculae more exactly in BM image, as compared with the methods of 8-Sobel operater. Canny operator and watershed algorithm. Bone trabeculae could be segmented with combinative methods of morphology and planimetry. The number of single precursor cells (19.27 ± 11.60)/mm(2) and double-cluster precursor cells (1.77 ± 1.76)/mm(2) in CR group were higher than that in normal controls (p < 0.05). The distance of single precursor cells from bone trabeculae in CR group were closer to bone trabeculae than that in controls [(230.12 ± 97.68) µm vs (260.92 ± 99.88 µm)] (p < 0.05), but the distance of double-cluster precursor cells from bone trabeculae in AML patients was (274.56 ± 139.48) µm, which showed no statistically significant different from controls (p > 0.05), while the double-cluster precursor cells showed the tendency of migrating to the intermediate zone of bone trabeculae compared with the single precursor cells in CR group (p < 0.05). It is concluded that the structure of "pre-ALIP" in BM tissue exists before the occurrence of ALIP. The characteristics of "pre-ALIP" are single and double-cluster precursor cells with abnormal localization or quantitation, which showed correlation with the development of AML.

[Earlier hematopoietic reconstitution by mouse cord blood transplantation combined with bone marrow c-kit(+) hematopoietic progenitor cells].

This study was purposed to investigate the accelerating effect of newborn mouse cord blood transplantation combined with hematopoietic progenitor cells of bone marrow (BM) on the early hematopoietic reconstitution after transplantation, and the long-term chimerism of cord blood-derived cells, so as to develop a combined transplantation method for accelerating the early hematopoietic reconstitution. The lin(-)sca-1(-)c-kit(+) (c-kit(+)) cells and lin(-)sca-1(+) (sca-1(+)) cells in the bone marrow of BDF1 mice were isolated by MACS method. Biological characteristics in vitro of isolated fractions were observed and compared by semisolid colony culture combined with Giemsa staining. After transplantation of cord blood (CB) alone, or together with graded numbers of either c-kit(+) or sca-1(+) cells isolated from BDF1 mice (CD45.1) bone marrow into lethally irradiated CD45.2 congenic BDF1 mice, numbers of WBC and platelet were measured within 22 days of post-transplantation. The proportion of chimerism on granulocyte, T and B cell was dynamically measured by flow cytometry within 60 weeks of post-transplantation. The results showed that the number of colony from BM c-kit(+) cells cultured in semi-solid agar medium was significantly smaller than that from BM sca-1(+) population, which showed low proliferative potential in vitro and morphological characteristics of medium- or large-sized blast-like cells. The co transplantation of CB and BM c-kit(+) cells or sca-1(+) cells at the dosages of 1 × 10(4) or 2.5 × 10(4) or 5 × 10(4) to recipient mice leads to the quantity of WBC and platelets increased to 1 × 10(9)/L and 1 × 10(12)/L at day 12, whereas the injection of CB alone resulted at day 17. When mice were transplanted with CB together with BM c-kit(+)cells, and the CB-donor type cells in the peripheral blood increased progressively, while congenic donor BM-derived stem cells decreased gradually. After cotransplantation with CB and BM c-kit(+) cells for 60 weeks, a frequency of complete chimerism in CB-derived cells was continually maintained in granulates (96.68 ± 2.68)% and B lymphocytes (92.55 ± 3.04)%, while T lymphocytes (67.96 ± 7.91)% were dominantly derived from CB. On the other hand, congenic bone marrow or residual-derived cells were the dominant population, and the ratio of CB-derived cells in the peripheral blood was less than 10% (6.19 ± 7.62)% after cotransplantation with CB and sca-1(+)cells for 60 weeks. It is concluded that the cotransplantation of CB and BM congenic c-kit(+) cells is able to accelerate early hematopoietic reconstitution of recipient mice due to congenic marrow cells. Complete or main chimerism of cord blood is formed in long-term multilineage reconstitution of granulocytes, B cells and T lymphocytes.