CXCR2 inhibition overcomes ponatinib intolerance by eradicating chronic myeloid leukemic stem cells through PI3K/Akt/mTOR and dipeptidylpeptidase â £ (CD26).

This study explores the therapeutic potential of targeting CXCR2 in patients afflicted with ponatinib-resistant chronic myeloid leukemia (CML). Ponatinib, a third-generation tyrosine kinase inhibitor (TKI), was initially designed for treating patients with CML harboring the T315I mutation. However, resistance or intolerance issues may lead to treatment discontinuation. Additionally, TKIs have exhibited limitations in eradicating quiescent CML stem cells. Our investigation reveals the activation of CXC chemokine receptor 2 (CXCR2) signaling in response to chemotherapeutic stress. Treatment with the CXCR2 antagonist, SB225002, effectively curtails cell proliferation and triggers apoptosis in ponatinib-resistant CML cells. SB225002 intervention also results in the accumulation of reactive oxygen species and disruption of mitochondrial function, phenomena associated with TKI chemoresistance and apoptosis. Furthermore, we demonstrate that activated CXCR2 expression induces the activity of dipeptidylpeptidase Ⅳ (DPP4/CD26), a CML leukemic stem cell marker, and concomitantly inhibits the PI3K/Akt/mTOR pathway cascades. These findings underscore the novel role of CXCR2 in the regulation of not only ponatinib-resistant CML cells, but also CML leukemic stem cells. Consequently, our study proposes that targeting CXCR2 holds promise as a viable therapeutic strategy for addressing patients with CML grappling with ponatinib resistance.

Generation of the human pluripotent stem cell lines KUMi005-A from a patients with multiple myeloma.

Multiple myeloma (MM) progresses with abnormal monoclonal proliferation and accumulation of malignant plasma cells in the bone marrow. We established human induced pluripotent stem cells (iPSCs), KUMi005-A, from bone marrow samples of a patient with MM. This reprogrammed cell line has similar characteristics to human embryonic stem cells, such as proliferation properties and pluripotency. KUMi005-A iPSCs may be applicable in MM disease modeling and cell-based therapies.

Generation of human induced iPSC KUMi003-A from acute promyelocytic leukemia (APL) M3.

Acute promyelocytic leukemia (APL) M3 is an acute myeloid leukemia (AML) subtype and is characterized by the chromosomal translocation t(15;17)(p22;q11), which results in the fusion of the promyelocytic gene (PML) at 15q22 with the retinoic acid α-receptor gene (RARA) at 17q21. We generated an induced pluripotent stem cell line "KUMi003-A" from an APL M3 patient that is pluripotent and can differentiate into the three germ layers. This iPSC line will be useful as a disease model to investigate disease mechanisms specific to APL M3.

PVR (CD155) Expression as a Potential Prognostic Marker in Multiple Myeloma.

Poliovirus receptor (PVR, CD155) is upregulated during tumor progression, and PVR expression is associated with poor prognosis in cancer patients; however, prognostic implications for PVR in multiple myeloma (MM) have not been investigated. PVR plays an immunomodulatory role by interacting with CD226, CD96, and TIGIT. TIGIT is a checkpoint inhibitory receptor that can limit adaptive and innate immunity, and it binds to PVR with the highest affinity. We used immunohistochemistry, ELISA, qPCR, and flow cytometry to investigate the role of PVR in MM. PVR was highly expressed in patients with MM, and membrane PVR expression showed a significant correlation with soluble PVR levels. PVR expression was significantly associated with the Revised-International Staging System stage, presence of extramedullary plasmacytoma and bone lesion, percentage of bone marrow plasma cells (BMPCs), and ß2-microglobulin levels, suggesting a possible role in advanced stages and metastasis. Furthermore, TIGIT expression was significantly correlated with the percentage of BMPCs. Patients with high PVR expression had significantly shorter overall and progression-free survival, and PVR expression was identified as an independent prognostic factor for poor MM survival. These findings indicate that PVR expression is associated with MM stage and poor prognosis, and is a potential prognostic marker for MM.

Generation of a human induced pluripotent stem cell line KUMi006 from a patient with multiple myeloma.

In this study, we report the generation of a novel human induced pluripotent stem cell (hiPSC) line from bone marrow mononuclear cells of a patient with multiple myeloma, using an integrative Sendai virus vector. This pluripotent cell line has been shown to differentiate into three germ layers. Therefore, these induced pluripotent stem cells (iPSCs) will enable not only advances in cell therapy products but also the study of mechanisms.

Regulation of sclerostin by the SIRT1 stabilization pathway in osteocytes.

Osteocytes play a critical role in bone remodeling through the secretion of paracrine factors regulating the differentiation and activity of osteoblasts and osteoclasts. Sclerostin is a key osteocyte-derived factor that suppresses bone formation and promotes bone resorption, therefore regulators of sclerostin secretion are a likely source of new therapeutic strategies for treatment of skeletal disorders. Here, we demonstrate that protein kinase CK2 (casein kinase 2) controls sclerostin expression in osteocytes via the deubiquitinase ubiquitin-specific peptidase 4 (USP4)-mediated stabilization of Sirtuin1 (SIRT1). Deletion of CK2 regulatory subunit, Csnk2b, in osteocytes (Csnk2bDmp1) results in low bone mass due to elevated levels of sclerostin. This phenotype in Csnk2bDmp1 mice was partly reversed when sclerostin expression was downregulated by a single intravenous injection with bone-targeting adeno-associated virus 9 (AAV9) carrying an artificial-microRNA that targets Sost. Mechanistically, CK2-induced phosphorylation of USP4 is important for stabilization of SIRT1 by suppressing ubiquitin-dependent proteasomal degradation. Upregulated expression of SIRT1 inhibits sclerostin transcription in osteocytes. Collectively, the CK2-USP4-SIRT1 pathway is crucial for the regulation of sclerostin expression in osteocytes to maintain bone homeostasis.

A human pluripotent stem cell line KUMi004-A generated from a patient with chronic lymphocytic leukemia.

Chronic lymphocytic leukemia (CLL) is a type of blood cancer caused by the abnormal accumulation of malignant plasma cells. In this study, we generated CLL iPSCs (KUMi004-a) using the Sendai virus, confirming pluripotency. Also, it can differentiate into three primary germ layers. We expect this cell line could be helpful to understand the pathology of CLL.

Generation of induced pluripotent stem cell line KUMi002-A with normal karyotype from a patient with Philadelphia chromosome-positive chronic myeloid leukemia.

Chronic myeloid leukemia (CML) is caused by the dysregulated tyrosine kinase activity of the BCR-ABL fusion protein. In this study, we generated induced pluripotent stem cells (iPSCs) with a normal karyotype, using cells from a patient with CML and a Philadelphia chromosome. These human iPSCs showed positive pluripotency markers and differentiated into three germ layers. This iPSC line can be useful for the study of CML, namely the biology of hematopoietic stem cells with normal karyotype in CML, and for the development of patient-specific immunological treatment.

Generation of the induced pluripotent stem cell line KUMi001-A carrying the Philadelphia chromosome from a chronic myeloid leukemia patient.

Chronic myeloid leukemia (CML) is caused by the BCR-ABL fusion protein, which dysregulates tyrosine kinase activity. In this study, we generated induced pluripotent stem cells (iPSCs) carrying the Philadelphia chromosome from a CML patient with the BCR-ABL fusion protein. CML iPSCs were positive for pluripotency markers and had the ability to differentiate into the three germ layers. This iPSC cell line could be useful for studying CML pathogenesis as well as for drug development to treat CML.

Prognostic Value of Galectin-9 Relates to Programmed Death-Ligand 1 in Patients With Multiple Myeloma.

Galectin-9 (Gal-9) expression can be negatively or positively associated with cancer patient prognosis, depending on the cancer type. However, the nature of this relationship remains unclear in multiple myeloma. Therefore, we evaluated the prognostic value of Gal-9 and its relationship with the expression of PD-L1 molecule, the most widely studied immune checkpoint inhibitor, in patients with newly diagnosed multiple myeloma. Gal-9 and PD-L1 levels in bone marrow aspirate samples were evaluated using immunofluorescence assays. Gal-9 positivity was defined as having ≥1% Gal-9-expressing plasma cells. PD-L1 expression was categorized as low or high based on its median value. The median OS of patients with positive and negative Gal-9 expression was 42 months and not reached, respectively. However, no significant difference was observed in OS between the two groups (P = 0.10). Patients with high PD-L1 expression had OS times of 14 and 43 months in the positive and negative Gal-9 expression groups, respectively. In the high PD-L1 expression group, patients expressing Gal-9 had significantly worse OS than those negative for it (P = 0.019). Multivariable Cox analysis confirmed that Gal-9 expression could independently predict shortened OS (hazard ratio, 1.090; 95% confidence interval, 1.015-1.171; P = 0.018) in patients with high PD-L1 expression. However, in the low PD-L1 expression group, patients with high Gal-9 expression exhibited a trend toward better OS (P = 0.816). Our results indicate that the prognostic value of Gal-9 may be related to PD-L1 expression in patients with newly diagnosed multiple myeloma.

CXCR2, a novel target to overcome tyrosine kinase inhibitor resistance in chronic myelogenous leukemia cells.

Chronic myeloid leukemia (CML) is a reciprocal translocation disorder driven by a breakpoint cluster region (BCR)-Abelson leukemia virus (ABL) fusion gene that stimulates abnormal tyrosine kinase activity. Tyrosine kinase inhibitors (TKIs) are effective in treating Philadelphia chromosome (Ph) + CML patients. However, the appearance of TKI-resistant CML cells is a hurdle in CML treatment. Therefore, it is necessary to identify novel alternative treatments targeting tyrosine kinases. This study was designed to determine whether C-X-C chemokine receptor 2 (CXCR2) could be a novel target for TKI-resistant CML treatment. Interleukin 8 (IL-8), a CXCR2 ligand, was significantly increased in the bone marrow serum of initially diagnosed CML patients and TKI-resistant CML cell conditioned media. CXCR2 antagonists suppressed the proliferation of CML cells via cell cycle arrest in the G2/M phase. CXCR2 inhibition also attenuated mTOR, c-Myc, and BCR-ABL expression, leading to CML cell apoptosis, irrespective of TKI responsiveness. Moreover, SB225002, a CXCR2 antagonist, caused higher cell death in TKI-resistant CML cells than TKIs. Using a mouse xenograft model, we confirmed that SB225002 suppresses tumor growth, with a prominent effect on TKI-resistant CML cells. Our findings demonstrate that IL-8 is a prognostic factor for the progression of CML. Inhibiting the CXCR2-mTOR-c-Myc cascade is a promising therapeutic strategy to overcome TKI-sensitive and TKI-insensitive CML. Thus, CXCR2 blockade is a novel therapeutic strategy to treat CML, and SB225002, a commercially available CXCR2 antagonist, might be a candidate drug that could be used to treat TKI-resistant CML.

Generation of normal induced pluripotent stem cell line KUMCi002-A from bone marrow CD34+ cells of patient with multiple myeloma disease having 13q deletion and IGH translocation.

Multiple myeloma (MM) is a hematological cancer characterized by an uncontrolled proliferation of antibody-secreting plasma cells within the bone marrow. Currently, cell therapy such as chimeric antigen receptor T-cell (CAR-T) based on induced pluripotent stem cells (iPSCs) has received attention for treating MM. However, the generation of iPSCs from MM patients appears to be very rarely reported. Here we generated an iPSC line from CD34+ bone marrow cells of a patient with MM using human placenta-derived cell conditioned medium (hPCCM), offering a relatively high efficiency in humanized conditions. This iPSC line might be a useful model for research on MM.

Supporting data on enhanced reprogramming of human CD34+ hematopoietic stem cells to induced pluripotent stem cells using human placenta-derived cell conditioned medium.

The data presented herein support "Generation of an induced pluripotent stem cell line KUMCi001-A from CD34+ bone marrow cells of a patient with acute lymphoblastic leukemia using human placenta-derived cell conditioned medium." The supplementary data were as follows. (1) Comparison of reprogramming efficiency of human placenta-derived cell conditioned medium with defined medium (mTeSR™1) and the generation of induced pluripotent stem cells (iPSCs) from a patient with acute lymphoblastic leukemia (ALL) with significantly higher reprogramming efficiency than that of the defined medium (P ≤ 0.05). (2) Evaluation of differentiation capability of the generated ALL_iPSCs into hematopoietic stem cells (HSCs) and comparison with normal iPSCs using the colony-forming unit (CFU) assay. ALL_iPSCs manifested all lineages for hematopoiesis in their colonies similar to normal iPSCs. (3) ALL_iPSCs showed a considerably higher number of burst-forming unit-erythroid colonies indicating the presence of more erythroid progenitors than normal iPSCs; this tendency was confirmed in the CFU assay of ALL_CD34+ cells. This has been previously reported as a feature of ALL. Thus, the hematopoietic characteristics of the donor patient with ALL appear to be maintained in our ALL_hiPSC line although the karyotype was normalized during reprogramming.

Generation of an induced pluripotent stem cell line KUMCi001-A from CD34+ bone marrow cells of a patient with acute lymphoblastic leukemia using human placenta-derived cell conditioned medium.

Many patients with acute lymphoblastic leukemia (ALL) show relapse post-chemotherapy. Therefore, it is important to develop a human induced pluripotent stem cell (hiPSC) line from ALL cells to verify the pathophysiology. However, the low efficiency of the established reprogramming protocol has hampered the development of ALL hiPSC lines. Our recently reported novel reprogramming method, using human placenta-derived cell conditioned medium (hPCCM), offers a relatively higher efficiency in humanized conditions. Here, we generated an hiPSC line from ALL-derived CD34+ bone marrow cells, using hPCCM for reprogramming. This hiPSC line might be a useful model for studies on ALL.

Bone-Targeting AAV-Mediated Gene Silencing in Osteoclasts for Osteoporosis Therapy.

Improper activity of bone-resorbing osteoclasts results in low bone density and deterioration of bone structure, which increase the risk of fractures. Anti-resorptive therapies targeting osteoclasts have proven effective in preserving bone mass, but these therapeutic agents lead to defective new bone formation and numerous potential side effects. In this study, we demonstrate that recombinant adeno-associated virus, serotype 9 (rAAV9) can deliver to osteoclasts an artificial microRNA (amiR) that silences expression of key osteoclast regulators, RANK (receptor activator for nuclear factor κB) and cathepsin K (rAAV9.amiR-rank, rAAV9.amiR-ctsk), to prevent bone loss in osteoporosis. As rAAV9 is highly effective for the transduction of osteoclasts, systemic administration of rAAV9 carrying amiR-rank or amiR-ctsk results in a significant increase of bone mass in mice. Furthermore, the bone-targeting peptide motif (Asp)14 or (AspSerSer)6 was grafted onto the AAV9-VP2 capsid protein, resulting in significant reduction of transgene expression in non-bone peripheral organs. Finally, systemic delivery of bone-targeting rAAV9.amiR-ctsk counteracts bone loss and improves bone mechanical properties in mouse models of postmenopausal and senile osteoporosis. Collectively, inhibition of osteoclast-mediated bone resorption via bone-targeting rAAV9-mediated silencing of ctsk is a promising gene therapy that can preserve bone formation and mitigate osteoporosis, while limiting adverse off-target effects.

CXCR2 Ligands and mTOR Activation Enhance Reprogramming of Human Somatic Cells to Pluripotent Stem Cells.

Induced pluripotent stem cell (iPSC) technology has great promise in regenerative medicine and disease modeling. In this study, we show that human placenta-derived cell conditioned medium stimulates chemokine (C-X-C motif) receptor 2 (CXCR2) in human somatic cells ectopically expressing the pluripotency-associated transcription factors Oct4, Sox2, Klf4, and cMyc (OSKM), leading to mechanistic target of rapamycin (mTOR) activation. This causes an increase in endogenous cMYC levels and a decrease in autophagy, thereby enhancing the reprogramming efficiency of human somatic cells into iPSCs. These findings were reproduced when human somatic cells after OSKM transduction were cultured in a widely used reprogramming medium (mTeSR) supplemented with CXCR2 ligands interleukin-8 and growth-related oncogene α or an mTOR activator (MHY1485). To our knowledge, this is the first report demonstrating that mTOR activation in human somatic cells with ectopic OSKM expression significantly enhances the production of iPSCs. Our results support the development of convenient protocols for iPSC generation and further our understanding of somatic cell reprogramming.

CXCR2 Inhibition in Human Pluripotent Stem Cells Induces Predominant Differentiation to Mesoderm and Endoderm Through Repression of mTOR, ß-Catenin, and hTERT Activities.

On the basis of our previous report verifying that chemokine (C-X-C motif) receptor 2 (CXCR2) ligands in human placenta-derived cell conditioned medium (hPCCM) support human pluripotent stem cell (hPSC) propagation without exogenous basic fibroblast growth factor (bFGF), this study was designed to identify the effect of CXCR2 manipulation on the fate of hPSCs and the underlying mechanism, which had not been previously determined. We observed that CXCR2 inhibition in hPSCs induces predominant differentiation to mesoderm and endoderm with concomitant loss of hPSC characteristics and accompanying decreased expression of mammalian target of rapamycin (mTOR), ß-catenin, and human telomerase reverse transcriptase (hTERT). These phenomena are recapitulated in hPSCs propagated in conventional culture conditions, including bFGF as well as those in hPCCM without exogenous bFGF, suggesting that the action of CXCR2 on hPSCs might not be associated with a bFGF-related mechanism. In addition, the specific CXCR2 ligand growth-related oncogene α (GROα) markedly increased the expression of ectodermal markers in differentiation-committed embryoid bodies derived from hPSCs. This finding suggests that CXCR2 inhibition in hPSCs prohibits the propagation of hPSCs and leads to predominant differentiation to mesoderm and endoderm owing to the blockage of ectodermal differentiation. Taken together, our results indicate that CXCR2 preferentially supports the maintenance of hPSC characteristics as well as facilitates ectodermal differentiation after the commitment to differentiation, and the mechanism might be associated with mTOR, ß-catenin, and hTERT activities.

CXCR2 and its related ligands play a novel role in supporting the pluripotency and proliferation of human pluripotent stem cells.

Basic fibroblast growth factor (bFGF) is a crucial factor sustaining human pluripotent stem cells (hPSCs). We designed this study to search the substitutive factors other than bFGF for the maintenance of hPSCs by using human placenta-derived conditioned medium without exogenous bFGF (hPCCM-), containing chemokine (C-X-C motif) receptor 2 (CXCR2) ligands, including interleukin (IL)-8 and growth-related oncogene α (GROα), which were developed on the basis of our previous studies. First, we confirmed that IL-8 and/or GROα play independent roles to preserve the phenotype of hPSCs. Then, we tried CXCR2 blockage of hPSCs in hPCCM- and verified the significant decrease of pluripotency-associated genes expression and the proliferation of hPSCs. Interestingly, CXCR2 suppression of hPSCs in mTeSR™1 containing exogenous bFGF decreased the proliferation of hPSCs while maintaining pluripotency characteristics. Lastly, we found that hPSCs proliferated robustly for more than 35 passages in hPCCM- on a gelatin substratum. Higher CXCR2 expression of hPSCs cultured in hPCCM- than those in mTeSR™1 was observable. Our findings suggest that CXCR2 and its related ligands might be novel factors comparable to bFGF supporting the characteristics of hPSCs and hPCCM- might be useful for the maintenance of hPSCs as well as for the accurate evaluation of CXCR2 role in hPSCs without the confounding influence of exogenous bFGF.