PIM1 overexpression in T-cell lymphomas protects tumor cells from apoptosis and confers doxorubicin resistance by upregulating c-myc expression

PIM Kinase Inhibition Sensitizes Neuroblastoma to Doxorubicin

BACKGROUND

Chemoresistance contributes to relapse in high-risk neuroblastoma. Cancer cells acquire resistance through multiple mechanisms, including drug efflux pumps. In neuroblastoma, multidrug resistance-associated protein-1 (MRP1/ABCC1) efflux pump expression correlates with worse outcomes. These pumps are regulated by PIM kinases, a family of serine-threonine kinases, overexpressed in neuroblastoma. We hypothesized PIM kinase inhibition would sensitize neuroblastoma cells by modulating MRP1.

METHODS

Kocak database query evaluated ABCC1, PIM1, PIM2, and PIM3 expression in neuroblastoma patients. SK-N-AS and SK-N-BE(2) cells were treated with doxorubicin or the pan-PIM kinase inhibitor, AZD1208. Flow cytometry assessed intracellular doxorubicin accumulation. AlamarBlue assay measured viability. The lethal dose 50% (LD50) of each drug and combination indices (CI) were calculated and isobolograms constructed to determine synergy.

RESULTS

Kocak database query demonstrated positive correlation between PIM genes and ABCC1. PIM kinase inhibition increased intracellular doxorubicin accumulation in both cell lines, suggesting PIM kinase regulation of MRP1. Isobolograms showed synergy between AZD1208 and doxorubicin.

CONCLUSIONS

The correlation between PIM and ABCC1 gene expression suggests PIM kinases may contribute to neuroblastoma chemotherapeutic resistance. PIM kinase inhibition increased intracellular doxorubicin accumulation. Combination treatment with AZD1208 and doxorubicin decreased neuroblastoma cell viability in a synergistic fashion. These findings support further investigations of PIM kinase inhibition in neuroblastoma.

TYPE OF STUDY

Basic Science Research.

LEVEL OF EVIDENCE

NA.

Chemotherapy-Enabled Colorectal Cancer Immunotherapy of Self-Delivery Nano-PROTACs by Inhibiting Tumor Glycolysis and Avoiding Adaptive Immune Resistance

The chemo-regulation abilities of chemotherapeutic medications are appealing to address the low immunogenicity, immunosuppressive lactate microenvironment, and adaptive immune resistance of colorectal cancer. In this work, the proteolysis targeting chimera (PROTAC) of BRD4 (dBET57) is found to downregulate colorectal cancer glycolysis through the transcription inhibition of c-Myc, which also inhibits the expression of programmed death ligand 1 (PD-L1) to reverse immune evasion and avoid adaptive immune resistance. Based on this, self-delivery nano-PROTACs (designated as DdLD NPs) are further fabricated by the self-assembly of doxorubicin (DOX) and dBET57 with the assistance of DSPE-PEG2000. DdLD NPs can improve the stability, intracellular delivery, and tumor targeting accumulation of DOX and dBET57. Meanwhile, the chemotherapeutic effect of DdLD NPs can efficiently destroy colorectal cancer cells to trigger a robust immunogenic cell death (ICD). More importantly, the chemo-regulation effects of DdLD NPs can inhibit colorectal cancer glycolysis to reduce the lactate production, and downregulate the PD-L1 expression through BRD4 degradation. Taking advantages of the chemotherapy and chemo-regulation ability, DdLD NPs systemically activated the antitumor immunity to suppress the primary and metastatic colorectal cancer progression without inducing any systemic side effects. Such self-delivery nano-PROTACs may provide a new insight for chemotherapy-enabled tumor immunotherapy.

LINC00460-FUS-MYC feedback loop drives breast cancer metastasis and doxorubicin resistance

Therapeutic resistance and metastasis largely contribute to mortality from breast cancer and therefore understanding the underlying mechanisms of such remains an urgent challenge. By cross-analysis of TCGA and GEO databases, LINC00460 was identified as an oncogenic long non-coding RNA, highly expressed in Doxorubicin resistant breast cancer. LINC00460 was further demonstrated to promote stem cell-like and epithelial-mesenchymal transition (EMT) characteristics in breast cancer cells. LINC00460 interacts with FUS protein with consequent enhanced stabilization, which further promotes MYC mRNA maturation. LINC00460 expression was transcriptionally enhanced by c-MYC protein, forming a positive feedback loop to promote metastasis and Doxorubicin resistance. LINC00460 depletion in Doxorubicin-resistant breast cancer cells restored sensitivity to Doxorubicin and increased the efficacy of c-MYC inhibitor therapy. Collectively, these findings implicate LINC00460 as a promising prognostic biomarker and potential therapeutic target to overcome Doxorubicin resistance in breast cancer.

circPVT1 and PVT1/AKT3 show a role in cell proliferation, apoptosis, and tumor subtype-definition in small cell lung cancer

Small cell lung cancer (SCLC) is treated as a homogeneous disease, although the expression of NEUROD1, ASCL1, POU2F3, and YAP1 identifies distinct molecular subtypes. The MYC oncogene, amplified in SCLC, was recently shown to act as a lineage-specific factor to associate subtypes with histological classes. Indeed, MYC-driven SCLCs show a distinct metabolic profile and drug sensitivity. To disentangle their molecular features, we focused on the co-amplified PVT1, frequently overexpressed and originating circular (circRNA) and chimeric RNAs. We analyzed hsa_circ_0001821 (circPVT1) and PVT1/AKT3 (chimPVT1) as examples of such transcripts, respectively, to unveil their tumorigenic contribution to SCLC. In detail, circPVT1 activated a pro-proliferative and anti-apoptotic program when over-expressed in lung cells, and knockdown of chimPVT1 induced a decrease in cell growth and an increase of apoptosis in SCLC in vitro. Moreover, the investigated PVT1 transcripts underlined a functional connection between MYC and YAP1/POU2F3, suggesting that they contribute to the transcriptional landscape associated with MYC amplification. In conclusion, we have uncovered a functional role of circular and chimeric PVT1 transcripts in SCLC; these entities may prove useful as novel biomarkers in MYC-amplified tumors.

Impact of Histone Modifications and Their Therapeutic Targeting in Hematological Malignancies

Hematologic malignancies are a large and heterogeneous group of neoplasms characterized by complex pathogenetic mechanisms. The abnormal regulation of epigenetic mechanisms and specifically, histone modifications, has been demonstrated to play a central role in hematological cancer pathogenesis and progression. A variety of epigenetic enzymes that affect the state of histones have been detected as deregulated, being either over- or underexpressed, which induces changes in chromatin compaction and, subsequently, affects gene expression. Recent advances in the field of epigenetics have revealed novel therapeutic targets, with many epigenetic drugs being investigated in clinical trials. The present review focuses on the biological impact of histone modifications in the pathogenesis of hematologic malignancies, describing a wide range of therapeutic agents that have been discovered to target these alterations and are currently under investigation in clinical trials.

Effects of microRNAs and long non-coding RNAs on chemotherapy response in glioma

Glioma is the most prevalent invasive primary tumor of the central nervous system. Glioma cells can spread and infiltrate into normal surrounding brain tissues. Despite the standard use of chemotherapy and radiotherapy after surgery in glioma patients, treatment resistance is still a problem, as the underlying mechanisms are still not fully understood. Non-coding RNAs are widely involved in tumor progression and treatment resistance mechanisms. In the present review, we discuss the pathways by which microRNAs and long non-coding RNAs can affect resistance to chemotherapy and radiotherapy, as well as offer potential therapeutic options for future glioma treatment.

HMGB1 Promotes Resistance to Doxorubicin in Human Hepatocellular Carcinoma Cells by Inducing Autophagy via the AMPK/mTOR Signaling Pathway

Chemoresistance remains as a major hindrance in the treatment of hepatocellular carcinoma (HCC). High mobility group box protein 1 (HMGB1) enhances autophagic flux and protects tumor cells from apoptosis, which results in acquired drug resistance. However, the exact mechanisms underlying HMGB1-modulated autophagy in HCC chemoresistance remain to be defined. In the present study, we found that administration of doxorubicin (DOX) significantly promoted HMGB1 expression and induced HMGB1 cytoplasmic translocation in human HCC cell lines BEL7402 and SMMC7721, which enhanced autophagy that contributes to protecting HCC cells from apoptosis and increasing drug resistance. Moreover, we observed HMGB1 translocation and elevation of autophagy in DOX-resistant BEL7402 and SMMC7721 cells. Additionally, inhibition of HMGB1 and autophagy increased the sensitivities of BEL-7402 and SMMC-7721 cells to DOX and re-sensitized their DOX-resistant cells. Subsequently, we confirmed with HMGB1 regulated autophagy by activating the 5ʹ adenosine monophosphate-activated protein kinase (AMPK)/mTOR pathway. In summary, our results indicate that HMGB1 promotes acquired DOX resistance in DOX-treated BEL7402 and SMMC7721 cells by enhancing autophagy through the AMPK/mTOR signaling pathway. These findings provide the proof-of-concept that HMGB1 inhibitors might be an important targeted treatment strategy for HCC.

Janus Kinase Signaling: Oncogenic Criminal of Lymphoid Cancers

Simple Summary

Janus kinases (JAKs) are transmembrane receptors that pass signals from extracellular ligands to downstream. Increasing evidence has suggested that JAK family aberrations promote lymphoid cancer pathogenesis and progression through mediating gene expression via the JAK/STAT pathway or noncanonical JAK signaling. We are here to review how canonical JAK/STAT and noncanonical JAK signalings are represented and deregulated in lymphoid malignancies and how to target JAK for therapeutic purposes.

Abstract

The Janus kinase (JAK) family are known to respond to extracellular cytokine stimuli and to phosphorylate and activate signal transducers and activators of transcription (STAT), thereby modulating gene expression profiles. Recent studies have highlighted JAK abnormality in inducing over-activation of the JAK/STAT pathway, and that the cytoplasmic JAK tyrosine kinases may also have a nuclear role. A couple of anti-JAK therapeutics have been developed, which effectively harness lymphoid cancer cells. Here we discuss mutations and fusions leading to JAK deregulations, how upstream nodes drive JAK expression, how classical JAK/STAT pathways are represented in lymphoid malignancies and the noncanonical and nuclear role of JAKs. We also summarize JAK inhibition therapeutics applied alone or synergized with other drugs in treating lymphoid malignancies.

Overexpression of microRNA‑486 affects the proliferation and chemosensitivity of mesothelioma cell lines by targeting PIM1

Dysregulated levels of microRNAs (miRNAs or miRs), involved in oncogenic pathways, have been proposed to contribute to the aggressiveness of malignant pleural mesothelioma (MPM). Previous studies have highlighted the downregulation of miRNA miR-486-5p in patients with mesothelioma and the introduction of miRNA mimics to restore their reduced or absent functionality in cancer cells is considered an important therapeutic strategy. The aim of the present study was to evaluate the mechanisms through which miRNAs may influence the functions, proliferation and sensitivity to cisplatin of MPM cells. In the present study, a miR-486-5p mimic was transfected into the H2052 and H28 MPM cell lines, and cell viability, proliferation, apoptosis and mitochondrial membrane potential were monitored. miR-486-5p overexpression led to a clear impairment of cell proliferation, targeting CDK4 and attenuating cell cycle progression. In addition, transfection with miR-486-5p mimic negatively regulated the release of inflammatory factors and the expression of Provirus integration site for Moloney murine leukaemia virus 1 (PIM1). The sensitivity of the cells to cisplatin was enhanced by enhancing the apoptotic effects of the drug and impairing mitochondrial function. On the whole, the present study demonstrates that miR-486-5p may play an important role in MPM treatment by targeting multiple pathways involved in tumour development and progression. These activities may be mostly related to the downregulation of PIM1, a crucial regulator of cell survival and proliferation. Furthermore, these results provide support for the combined use of miR-486-5p with chemotherapy as a therapeutic strategy for MPM.

Mutational Profile and Clonal Evolution of Relapsed/Refractory Diffuse Large B-Cell Lymphoma

Primary refractory/relapsed diffuse large B-cell lymphoma (rrDLBCL) is an unresolved issue for DLBCL treatment and new treatments to overcome resistance is required. To explore the genetic mechanisms underlying treatment resistance in rrDLBCL and to identify candidate genes, we performed targeted deep sequencing of 430 lymphoma-related genes from 58 patients diagnosed with rrDLBCL. Genetic alterations found between the initial biopsy and biopsy at recurrence or refractory disease were investigated. The genes most frequently altered (> 20%) were (in decreasing order of frequency) CDKN2A, PIM1, CD79B, TP53, MYD88, MYC, BTG2, BTG1, CDKN2B, DTX1, CD58, ETV6, and IRF4. Genes mutation of which in pretreatment sample were associated with poor overall survival included NOTCH1, FGFR2, BCL7A, BCL10, SPEN and TP53 (P < 0.05). FGFR2, BCL2, BCL6, BCL10, and TP53 were associated with poor progression-free survival (P < 0.05). Most mutations were truncal and were maintained in both the initial biopsy and post-treatment biopsy with high dynamics of subclones. Immune-evasion genes showed increased overall mutation frequency (CD58, B2M) and variant allele fraction (CD58), and decreased copy number (B2M, CD70) at the post-treatment biopsy. Using the established mutational profiles and integrative analysis of mutational evolution, we identified information about candidate genes that may be useful for the development of future treatment strategies.

Rebelled epigenome: histone H3S10 phosphorylation and H3S10 kinases in cancer biology and therapy

Background

With the discovery that more than half of human cancers harbor mutations in chromatin proteins, deregulation of epigenetic mechanisms has been recognized a hallmark of malignant transformation. Post-translational modifications (PTMs) of histone proteins, as main components of epigenetic regulatory machinery, are also broadly accepted as therapeutic target. Current “epigenetic” therapies target predominantly writers, erasers and readers of histone acetylation and (to a lesser extent) methylation, leaving other types of PTMs largely unexplored. One of them is the phosphorylation of serine 10 on histone H3 (H3S10ph).

Main body

H3S10ph is emerging as an important player in the initiation and propagation of cancer, as it facilitates cellular malignant transformation and participates in fundamental cellular functions. In normal cells this histone mark dictates the hierarchy of additional histone modifications involved in the formation of protein binding scaffolds, transcriptional regulation, blocking repressive epigenetic information and shielding gene regions from heterochromatin spreading. During cell division, this mark is essential for chromosome condensation and segregation. It is also involved in the function of specific DNA–RNA hybrids, called R-loops, which modulate transcription and facilitate chromosomal instability. Increase in H3S10ph is observed in numerous cancer types and its abundance has been associated with inferior prognosis. Many H3S10-kinases, including MSK1/2, PIM1, CDK8 and AURORA kinases, have been long considered targets in cancer therapy. However, since these proteins also participate in other critical processes, including signal transduction, apoptotic signaling, metabolic fitness and transcription, their chromatin functions are often neglected.

Conclusions

H3S10ph and enzymes responsible for deposition of this histone modification are important for chromatin activity and oncogenesis. Epigenetic-drugs targeting this axis of modifications, potentially in combination with conventional or targeted therapy, provide a promising angle in search for knowledge-driven therapeutic strategies in oncology.

Long Noncoding RNA KCNQ1OT1 Confers Gliomas Resistance to Temozolomide and Enhances Cell Growth by Retrieving PIM1 From miR-761

Many studies have found that the dysregulation of long noncoding RNA (lncRNA) contributed to cancer initiation, progression, and recurrence via multiple signaling pathways. However, the underlying mechanisms of lncRNA in temozolomide (TMZ)-resistant gliomas were not well understood, hindering the improvement of TMZ-based therapies. The present study demonstrated that the lncRNA KCNQ1OT1 increased in TMZ-resistant glioma cells compared to the TMZ-sensitive cells. The introduction of KCNQ1OT1 promoted cell viability, clonogenicity, and rhodamine 123 efflux while hampering TMZ-induced apoptosis. Moreover, KCNQ1OT1 directly sponged miR-761, which decreased in TMZ-resistant sublines. The overexpression of miR-761 attenuated cell viability and clonogenicity, while triggering apoptosis and rhodamine 123 accumulation post-TMZ exposure, leading to a response to TMZ. The interaction between miR-761 and 3'-untranslated region of PIM1 attenuated PIM1-mediated signaling cascades. Furthermore, the knockdown of KCNQ1OT1 augmented the TMZ-induced tumor regression in TMZ-resistant U251 mouse models. Briefly, the present study evaluated that KCNQ1OT1 conferred TMZ resistance by releasing PIM1 expression from miR-761, resulting in the upregulation of PIM-mediated MDR1, c-Myc, and Survivin. The present findings demonstrated that the interplay of KCNQ1OT1: miR-761: PIM1 regulated chemoresistance in gliomas and provided a promising therapeutic target for TMZ-resistant glioma patients.

Selective protection of human cardiomyocytes from anthracycline cardiotoxicity by small molecule inhibitors of MAP4K4

Given the poor track record to date of animal models for creating cardioprotective drugs, human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have been proposed as a therapeutically relevant human platform to guide target validation and cardiac drug development. Mitogen-Activated Protein Kinase Kinase Kinase Kinase-4 (MAP4K4) is an “upstream” member of the MAPK superfamily that is implicated in human cardiac muscle cell death from oxidative stress, based on gene silencing and pharmacological inhibition in hPSC-CMs. A further role for MAP4K4 was proposed in heart muscle cell death triggered by cardiotoxic anti-cancer drugs, given its reported activation in failing human hearts with doxorubicin (DOX) cardiomyopathy, and its activation acutely by DOX in cultured cardiomyocytes. Here, we report successful protection from DOX in two independent hPSC-CM lines, using two potent, highly selective MAP4K4 inhibitors. The MAP4K4 inhibitors enhanced viability and reduced apoptosis at otherwise lethal concentrations of DOX, and preserved cardiomyocyte function, as measured by spontaneous calcium transients, at sub-maximal ones. Notably, in contrast, no intereference was seen in tumor cell killing, caspase activation, or mitochondrial membrane dissipation by DOX, in human cancer cell lines. Thus, MAP4K4 is a plausible, tractable, selective therapeutic target in DOX-induced human heart muscle cell death.

[Expression and role of Pim1 in cultured cortical neurons with oxygen-glucose deprivation/reoxygen injury]

OBJECTIVE

To study the expression and effect of Pim1 in primary cortical neurons after hypoxic-ischemic injury.

METHODS

Cortical neurons were isolated from 1-day-old C57BL/6 mice and cultured in neurobasal medium. On the 8th day of neuron culture, cells were subjected to oxygen-glucose deprivation/reoxygen (OGD/R) treatment to mimic in vivo hypoxic injury of neurons. Briefly, medium were changed to DMEM medium, and cells were cultured in 1% O₂ for 3 hours and then changed back to normal medium and conditions. Cells were collected at 0 hour, 6 hours, 12 hours and 24 hours after OGD/R. Primary neurons were transfected with Pim1 overexpression plasmid or mock plasmid, and then were exposed to normal conditions or OGD/R treatment. They were named as Pim1 group, control group, OGD/R group and OGD/R+Pim1 group respectively. Real-time PCR was used to detect Pim1 mRNA expression. Western blot was used to detect the protein expression of Pim1 and apoptotic related protein cleaved caspase 3 (CC3). TUNEL staining was used to detect cell apoptosis.

RESULTS

Real-time PCR and Western blot results showed that Pim1 mRNA and protein were significantly decreased in neurons after OGD/R. They began to decrease at 0 hour after OGD/R, reached to the lowest at 12 hours after OGD/R, and remained at a lower level at 24 hours after OGD/R (P<0.01). Overexpression of Pim1 significantly upregulated the protein level of Pim1. Under OGD/R conditions, the CC3 expression and the apoptosis rate in cells of the Pim1 group were significantly lower than in un-transfected cells (P<0.01).

CONCLUSIONS

Hypoxic-ischemic injury may decrease Pim1 expression in neurons. Overexpressed Pim1 may inhibit apoptosis induced by OGD/R.

The targetable kinase PIM1 drives ALK inhibitor resistance in high-risk neuroblastoma independent of MYCN status

Resistance to anaplastic lymphoma kinase (ALK)-targeted therapy in ALK-positive non-small cell lung cancer has been reported, with the majority of acquired resistance mechanisms relying on bypass signaling. To proactively identify resistance mechanisms in ALK-positive neuroblastoma (NB), we herein employ genome-wide CRISPR activation screens of NB cell lines treated with brigatinib or ceritinib, identifying PIM1 as a putative resistance gene, whose high expression is associated with high-risk disease and poor survival. Knockdown of PIM1 sensitizes cells of differing MYCN status to ALK inhibitors, and in patient-derived xenografts of high-risk NB harboring ALK mutations, the combination of the ALK inhibitor ceritinib and PIM1 inhibitor AZD1208 shows significantly enhanced anti-tumor efficacy relative to single agents. These data confirm that PIM1 overexpression decreases sensitivity to ALK inhibitors in NB, and suggests that combined front-line inhibition of ALK and PIM1 is a viable strategy for the treatment of ALK-positive NB independent of MYCN status.