Inhibition of BMP and of TGFβ receptors downregulates expression of XIAP and TAK1 leading to lung cancer cell death

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

Antioncogenic roles of USP9Y and DDX3Y in lung cancer: USP9Y stabilizes DDX3Y by preventing its degradation through deubiquitination

In previous studies, downregulation of USP9Y and DDX3Y in lung cancer (LC) tissues was identified, while their function in LC progression remains elusive. In our current work, we intended to elucidate the effect and mechanisms of USP9Y and DDX3Y in LC. Gene downregulation has been confirmed in our LC tissues and cells. The effect of USP9Y or DDX3Y on LC cell malignancies was analyzed by functional assay. Both USP9Y and DDX3Y overexpression showed suppressive impact on LC cell malignancies. USP9Y overexpression has also been demonstrated to inhibit tumorigenesis in vivo. Based on GEPIA database, it was found that there was a positive correlation between the levels of USP9Y and DDX3Y in LC tissues. The mRNA expression of DDX3Y was not affected by USP9Y overexpression, while its protein levels were significantly up-regulated in USP9Y overexpressed LC cells. Moreover, USP9Y interacted with DDX3Y and has been demonstrated to stabilize DDX3Y expression by preventing its degradation via deubiquitination. In conclusion, USP9Y and DDX3Y exerted antioncogenic effects on the cell proliferation potential, cell cycle process, apoptosis, and tumorigenesis of LC. USP9Y binds to DDX3Y to prevent DDX3Y degradation through deubiquitination.

BMP signaling in cancer stemness and differentiation

The BMP (Bone morphogenetic protein) signaling pathway plays a central role in metazoan biology, intricately shaping embryonic development, maintaining tissue homeostasis, and influencing disease progression. In the context of cancer, BMP signaling exhibits context-dependent dynamics, spanning from tumor suppression to promotion. Cancer stem cells (CSCs), a modest subset of neoplastic cells with stem-like attributes, exert substantial influence by steering tumor growth, orchestrating therapy resistance, and contributing to relapse. A comprehensive grasp of the intricate interplay between CSCs and their microenvironment is pivotal for effective therapeutic strategies. Among the web of signaling pathways orchestrating cellular dynamics within CSCs, BMP signaling emerges as a vital conductor, overseeing CSC self-renewal, differentiation dynamics, and the intricate symphony within the tumor microenvironment. Moreover, BMP signaling's influence in cancer extends beyond CSCs, intricately regulating cellular migration, invasion, and metastasis. This multifaceted role underscores the imperative of comprehending BMP signaling's contributions to cancer, serving as the foundation for crafting precise therapies to navigate multifaceted challenges posed not only by CSCs but also by various dimensions of cancer progression. This article succinctly encapsulates the diverse roles of the BMP signaling pathway across different cancers, spanning glioblastoma multiforme (GBM), diffuse intrinsic pontine glioma (DIPG), colorectal cancer, acute myeloid leukemia (AML), lung cancer, prostate cancer, and osteosarcoma. It underscores the necessity of unraveling underlying mechanisms and molecular interactions. By delving into the intricate tapestry of BMP signaling's engagement in cancers, researchers pave the way for meticulously tailored therapies, adroitly leveraging its dualistic aspects-whether as a suppressor or promoter-to effectively counter the relentless march of tumor progression.

Transforming growth factor-β and bone morphogenetic protein signaling pathways in pathological cardiac hypertrophy

Pathological cardiac hypertrophy (referred to as cardiac hypertrophy) is a maladaptive response of the heart to a variety of pathological stimuli, and cardiac hypertrophy is an independent risk factor for heart failure and sudden death. Currently, the treatments for cardiac hypertrophy are limited to improving symptoms and have little effect. Elucidation of the developmental process of cardiac hypertrophy at the molecular level and the identification of new targets for the treatment of cardiac hypertrophy are crucial. In this review, we summarize the research on multiple active substances related to the pathogenesis of cardiac hypertrophy and the signaling pathways involved and focus on the role of transforming growth factor-β (TGF-β) and bone morphogenetic protein (BMP) signaling in the development of cardiac hypertrophy and the identification of potential targets for molecular intervention. We aim to identify important signaling molecules with clinical value and hope to help promote the precise treatment of cardiac hypertrophy and thus improve patient outcomes.

Interleukin-6 and pulmonary hypertension: from physiopathology to therapy

Pulmonary hypertension (PH) is a progressive, pulmonary vascular disease with high morbidity and mortality. Unfortunately, the pathogenesis of PH is complex and remains unclear. Existing studies have suggested that inflammatory factors are key factors in PH. Interleukin-6 (IL-6) is a multifunctional cytokine that plays a crucial role in the regulation of the immune system. Current studies reveal that IL-6 is elevated in the serum of patients with PH and it is negatively correlated with lung function in those patients. Since IL-6 is one of the most important mediators in the pathogenesis of inflammation in PH, signaling mechanisms targeting IL-6 may become therapeutic targets for this disease. In this review, we detailed the potential role of IL-6 in accelerating PH process and the specific mechanisms and signaling pathways. We also summarized the current drugs targeting these inflammatory pathways to treat PH. We hope that this study will provide a more theoretical basis for targeted treatment in patients with PH in the future.

Mechanism and function of miR-140 in human cancers: A review and in silico study

MicroRNA-140 (miR-140) acts as a tumor suppressor and plays a vital role in cell biological functions such as cell proliferation, apoptosis, and DNA repair. The expression of this miRNA has been shown to be considerably decreased in cancer tissues and cell lines compared with normal adjacent tissues. Consequently, aberrant expression of some miR-140 target genes can lead to the initiation and progression of various human cancers, such as breast cancer, gastrointestinal cancers, lung cancer, and prostate cancer. The dysregulation of the miR-140 network also affects cell proliferation, invasion, metastasis, and apoptosis of cancer cells by affecting various signaling pathways. Besides, up-regulation of miR-140 could enhance the efficacy of chemotherapeutic agents in different cancer. We aimed to cover most aspects of miR-140 function in cancer development and address its importance in different stages of cancer progression.

Ym155 localizes to the mitochondria leading to mitochondria dysfunction and activation of AMPK that inhibits BMP signaling in lung cancer cells

The imidazolium compound Ym155 was first reported to be a survivin inhibitor. Ym155 potently induces cell death of many types of cancer cells in preclinical studies. However, in phase II clinical trials Ym155 failed to demonstrate a significant benefit. Studies have suggested that the cytotoxic effects of Ym155 in cancer cells are not mediated by the inhibition of survivin. Understanding the mechanism by which Ym155 induces cell death would provide important insight how to improve its efficacy as a cancer therapeutic. We demonstrate a novel mechanism by which Ym155 induces cell death by localizing to the mitochondria causing mitochondrial dysfunction. Our studies suggest that Ym155 binds mitochondrial DNA leading to a decrease in oxidative phosphorylation, decrease in TCA cycle intermediates, and an increase in mitochondrial permeability. Furthermore, we show that mitochondrial stress induced by Ym155 and other mitochondrial inhibitors activates AMP-activated kinase leading to the downregulation to bone morphogenetic protein (BMP) signaling. We provide first evidence that Ym155 initiates cell death by disrupting mitochondrial function.

PPDPF promotes lung adenocarcinoma progression via inhibiting apoptosis and NK cell-mediated cytotoxicity through STAT3

Lung cancer is the most common malignancy and the leading cause of cancer death worldwide, and lung adenocarcinoma (LUAD) is the most prevalent subtype. Considering the emergence of resistance to therapies, it is urgent to develop more effective therapies to improve the prognosis. Here we reported that pancreatic progenitor cell differentiation and proliferation factor (PPDPF) deficiency inhibited LUAD development both in vitro and in vivo. Mechanistically, PPDPF induces hyperactive STAT3 by interfering STAT3-PTPN1 interaction. Activated STAT3 promoted BMPR2 transcription, which further inhibited apoptosis. Moreover, PPDPF reduced NK cell infiltration and activation to develop an immunosuppressive microenvironment, which was also mediated by STAT3. Furthermore, we identified that the expression of PPDPF was positively correlated with the malignant features of LUAD, as well as BMPR2 and p-STAT3 level in clinical samples. Therefore, our study suggests that PPDPF positively regulates BMPR2 expression and facilitates immune escape via regulating STAT3 activity, providing a potential therapy target for LUAD.

Bone morphogenetic protein inhibitors and mitochondria targeting agents synergistically induce apoptosis-inducing factor (AIF) caspase-independent cell death in lung cancer cells

BACKGROUND

Bone morphogenetic proteins (BMP) are evolutionarily conserved morphogens that are reactivated in lung carcinomas. In lung cancer cells, BMP signaling suppresses AMP activated kinase (AMPK) by inhibiting LKB1. AMPK is activated by mitochondrial stress that inhibits ATP production, which is enhanced 100-fold when phosphorylated by LKB1. Activated AMPK can promote survival of cancer cells but its "hyperactivation" induces cell death. The studies here reveal novel cell death mechanisms induced by BMP inhibitors, together with agents targeting the mitochondria, which involves the "hyperactivation" of AMPK.

METHODS

This study examines the synergistic effects of two BMP inhibitors together with mitochondrial targeting agents phenformin and Ym155, on cell death of lung cancer cells expressing LKB1 (H1299), LKB1 null (A549), and A549 cells transfected with LKB1 (A549-LKB1). Cell death mechanisms evaluated were the activation of caspases and the nuclear localization of apoptosis inducing factor (AIF). A769662 was used to allosterically activate AMPK. Knockdown of BMPR2 and LKB1 using siRNA was used to examine their effects on nuclear localization of AMPK. Validation studies were performed on five passage zero primary NSCLC.

RESULTS

Both BMP inhibitors synergistically suppressed growth when combined with Ym155 or phenformin in cells expressing LKB1. The combination of BMP inhibitors with mitochondrial targeting agents enhanced the activation of AMPK in lung cancer cells expressing LKB1. Allosteric activation of AMPK with A769662 induced cell death in both H1299 and A549 cells. Cell death induced by the combination of BMP inhibitors and mitochondrial-targeting agents did not activate caspases. The combination of drugs induced nuclear localization of AIF in cells expressing LKB1, which was attenuated by knockdown of LKB1. Knockdown of BMPR2 together with Ym155 increased nuclear localization of AIF. Combination therapy also enhanced cell death and AIF nuclear localization in primary NSCLC.

CONCLUSIONS

These studies demonstrate that inhibition of BMP signaling together with mitochondrial targeting agents induce AIF caspase-independent cell death, which involves the "hyperactivation" of AMPK. AIF caspase-independent cell death is an evolutionarily conserved cell death pathway that is infrequently studied in cancer. These studies provide novel insight into mechanisms inducing AIF caspase-independent cell death in cancer cells using BMP inhibitors. Video Abstract.

Bone morphogenetic protein signaling regulation of AMPK and PI3K in lung cancer cells and C. elegans

BACKGROUND

Bone morphogenetic protein (BMP) is a phylogenetically conserved signaling pathway required for development that is aberrantly expressed in several age-related diseases including cancer, Alzheimer's disease, obesity, and cardiovascular disease. Aberrant BMP signaling in mice leads to obesity, suggesting it may alter normal metabolism. The role of BMP signaling regulating cancer metabolism is not known.

METHODS

To examine BMP regulation of metabolism, C. elegans harboring BMP gain-of-function (gof) and loss-of-function (lof) mutations were examined for changes in activity of catabolic and anabolic metabolism utilizing Western blot analysis and fluorescent reporters. AMP activated kinase (AMPK) gof and lof mutants were used to examine AMPK regulation of BMP signaling. H1299 (LKB1 wild-type), A549 (LKB1 lof), and A549-LKB1 (LKB1 restored) lung cancer cell lines were used to study BMP regulation of catabolic and anabolic metabolism. Studies were done using recombinant BMP ligands to activate BMP signaling, and BMP receptor specific inhibitors and siRNA to inhibit signaling.

RESULTS

BMP signaling in both C. elegans and cancer cells is responsive to nutrient conditions. In both C. elegans and lung cancer cell lines BMP suppressed AMPK, the master regulator of catabolism, while activating PI3K, a regulator of anabolism. In lung cancer cells, inhibition of BMP signaling by siRNA or small molecules increased AMPK activity, and this increase was mediated by activation of LKB1. BMP2 ligand suppressed AMPK activation during starvation. BMP2 ligand decreased expression of TCA cycle intermediates and non-essential amino acids in H1299 cells. Furthermore, we show that BMP activation of PI3K is mediated through BMP type II receptor. We also observed feedback signaling, as AMPK suppressed BMP signaling, whereas PI3K increased BMP signaling.

CONCLUSION

These studies show that BMP signaling suppresses catabolic metabolism and stimulates anabolic metabolism. We identified feedback mechanisms where catabolic induced signaling mediated by AMPK negatively regulates BMP signaling, whereas anabolic signaling produces a positive feedback regulation of BMP signing through Akt. These mechanisms were conserved in both lung cancer cells and C. elegans. These studies suggest that aberrant BMP signaling causes dysregulation of metabolism that is a potential mechanism by which BMP promotes survival of cancer cells.

Bone morphogenetic protein receptor inhibitors suppress the growth of glioblastoma cells

Glioblastomas (GBMs) are aggressive brain tumors that are resistant to chemotherapy and radiation. Bone morphogenetic protein (BMP) ligand BMP4 is being examined as a potential therapeutic for GBMs because it induces differentiation of cancer stem cells (CSCs) to an astrocyte phenotype. ID1 is reported to promote self-renewal and inhibit CSC differentiation. In most cancers, ID1 is transcriptionally upregulated by BMP4 promoting invasion and stemness. This conflicting data bring into question whether BMP signaling is growth suppressive or growth promoting in GBMs. We utilized BMP inhibitors DMH1, JL5, and Ym155 to examine the role of BMP signaling on the growth of GBMs. DMH1 targets BMP type 1 receptors whereas JL5 inhibits both the type 1 and type 2 BMP receptors. Ym155 does not bind the BMP receptors but rather inhibits BMP signaling by inducing the degradation of BMPR2. We show that JL5, DMH1, and Ym155 decreased the expression of ID1 in SD2 and U87 cells. JL5 and Ym155 also decreased the expression of BMPR2 and its downstream target inhibitor of apoptosis protein XIAP. JL5 treatment resulted in significant cell death and suppressed self-renewal to a greater extent than that induced by BMP4 ligand. The lysosome inhibitor chloroquine increases the localization of BMPR2 to the plasma membrane enhancing JL5-induced downregulation of ID1 and cell death in SD2 cells. We show that BMP signaling is growth promoting in GBMs. These studies suggest the need for development of BMP inhibitors and evaluation as potential therapeutic for GBMs.

Two Modulators of Skeletal Development: BMPs and Proteoglycans

During embryogenesis, skeletal development is tightly regulated by locally secreted growth factors that interact with proteoglycans (PGs) in the extracellular matrix (ECM). Bone morphogenetic proteins (BMPs) are multifunctional growth factors that play critical roles in cartilage maturation and bone formation. BMP signals are transduced from plasma membrane receptors to the nucleus through both canonical Smad and noncanonical p38 mitogen-activated protein kinase (MAPK) pathways. BMP signalling is modulated by a variety of endogenous and exogenous molecular mechanisms at different spatiotemporal levels and in both positive and negative manners. As an endogenous example, BMPs undergo extracellular regulation by PGs, which generally regulate the efficiency of ligand-receptor binding. BMP signalling can also be exogenously perturbed by a group of small molecule antagonists, such as dorsomorphin and its derivatives, that selectively bind to and inhibit the intracellular kinase domain of BMP type I receptors. In this review, we present a current understanding of BMPs and PGs functions in cartilage maturation and osteoblast differentiation, highlighting BMP–PG interactions. We also discuss the identification of highly selective small-molecule BMP receptor type I inhibitors. This review aims to shed light on the importance of BMP signalling and PGs in cartilage maturation and bone formation.

The role of miR-370 and miR-138 in the regulation of BMP2 suppressor gene expression in colorectal cancer: preliminary studies

PURPOSE

Colorectal cancer (CRC) is the fourth-most common cancer worldwide and the second most common cancer cause of death in the world. The components of the TGFβ-signalling pathway, which are often affected by miRNAs, are involved in the regulation of apoptosis and cell cycle. Therefore, in the current study, the expression of BMP2 gene in CRC tissues at different clinical stages compared to the non-tumour tissues has been assessed. Moreover, the plasma BMP2 protein concentration in the same group of CRC patients has been validated. Due to the constant necessity to conduct further research of the correlation between specific miRNAs and mRNAs in CRC, in silico analysis has been performed to select miRNAs that regulate BMP2 mRNA.

METHODS

The cDNA samples from tumor and non-tumor tissue were used in a qPCR reaction to determine the mRNA expression of the BMP2 gene and the expression of selected miRNAs. The concentration of BMP2 protein in plasma samples was also measured.

RESULTS

It was indicated that BMP2 was downregulated in CRC tissue. Moreover, miR-370 and miR-138 expression showed an upward trend. Decreased BMP2 with accompanied increasing miR-370 and miR-138 expression was relevant to the malignant clinicopathological features of CRC and consequently poor patient prognosis.

CONCLUSION

Our data suggest that miR-370 with its clear expression in plasma samples may be a potential diagnostic marker to determine the severity of the disease in patients at a later stage of colorectal cancer.

MicroRNA-5100 Modulates Lung Cancer Cell Proliferation and Apoptosis via Inhibiting X-Linked Inhibitor of Apoptosis Protein (XIAP) Expression

This study assesses the miR-5100 expression and its function in human lung cancer. The expression of miR-5100 was analyzed by miScript miRNA method. Cancer cells were transfected with miR-5100 mimics (miR-5100), miR-5100 inhibitors (ASO-miR-5100), XIAP inhibitors (si-XIAP), negative controls (NC) followed by analysis of cell proliferation by MTT and apoptosis by flow cytometry, the expression of XIAP related proteins by Western blot. miR-5100’ target was predicted by bioinformatics website and verified by dual luciferase assay. Finally, a xenogeneic tumor inhibition model was established to detect tumor progression after treatments. Lung cancer cells and tissues exhibited significantly reduced miR-5100 level. Dual luciferase assay showed that miR-5100 bound XIAP 3′-UTR and reduced XIAP mRNA and protein level. Further, miR-5100 inhibited cell proliferation, increased apoptosis and the expression of cleaved-capsase-3 and cleaved-capsase-9, the XIAP downstream factor. Finally, miR-5100 inhibited tumor growth, decreased cellular proliferation and promoted apoptosis, accompanied by reduced XIAP expression in vivo. miR-5100 inhibits lung cancer cell proliferation and enhances apoptosis through inhibiting XIAP expression in vitro and in vivo.

Bone morphogenetic protein receptor 2 inhibition destabilizes microtubules promoting the activation of lysosomes and cell death of lung cancer cells

Background

Recent studies have shown that bone morphogenetic protein receptor 2 (BMPR2) regulates cell survival signaling events in cancer cells independent of the BMP type 1 receptor (BMPR1) or the Smad-1/5 transcription factor. Mutations in BMPR2 trafficking proteins leads to overactive BMP signaling, which leads to neurological diseases caused by BMPR2 stabilization of the microtubules. It is not known whether BMPR2 regulates the microtubules in cancer cells and what effect this has on cell survival. It is also not known whether alterations in BMPR2 trafficking effects activity and response to BMPR2 inhibitors.

Methods

We utilized BMPR2 siRNA and the BMP receptor inhibitors JL5 and Ym155, which decrease BMPR2 signaling and cause its mislocalization to the cytoplasm. Using the JL5 resistant MDA-MD-468 cell line and sensitive lung cancer cell lines, we examined the effects of BMPR2 inhibition on BMPR2 mislocalization to the cytoplasm, microtubule destabilization, lysosome activation and cell survival.

Results

We show that the inhibition of BMPR2 destabilizes the microtubules. Destabilization of the microtubules leads to the activation of the lysosomes. Activated lysosomes further decreases BMPR2 signaling by causing it to mislocalizated to the cytoplasm and/or lysosome for degradation. Inhibition of the lysosomes with chloroquine attenuates BMPR2 trafficking to the lysosome and cell death induced by BMPR2 inhibitors. Furthermore, in MDA-MD-468 cells that are resistant to JL5 induced cell death, BMPR2 was predominately located in the cytoplasm. BMPR2 failed to localize to the cytoplasm and/or lysosome following treatment with JL5 and did not destabilize the microtubules or activate the lysosomes.

Conclusions

These studies reveal that the inhibition of BMPR2 destabilizes the microtubules promoting cell death of cancer cells that involves the activation of the lysosomes. Resistance to small molecules targeting BMPR2 may occur if the BMPR2 is localized predominantly to the cytoplasm and/or fails to localize to the lysosome for degradation.

Inhibiting roles of FOXA2 in liver cancer cell migration and invasion by transcriptionally suppressing microRNA-103a-3p and activating the GREM2/LATS2/YAP axis

Forkhead box A2 (FOXA2) has emerged as a tumor inhibitor in several human malignancies. This work focused on the effect of FOXA2 on liver cancer (LC) cell invasion and migration and the involving molecules. FOXA2 expression in LC tissues and cell lines was determined. The potential target microRNA (miRNA) of FOXA2 was predicted via bioinformatic analysis and validated through a ChIP assay. The mRNA target of miRNA-103a-3p was predicted via bioinformatic analysis and confirmed via a luciferase assay. Altered expression of FOXA2, miR-103a-3p and GREM2 was introduced in cells to identify their roles in LC cell migration and invasion. Consequently, FOXA2 and GREM2 were poorly expressed while miR-103a-3p was highly expressed in LC samples. Overexpression of FOXA2 or GREM2 suppressed migration and invasion of LC cells, while up-regulation of miR-103a-3p led to inverse trends. FOXA2 transcriptionally suppressed miR-103a-3p to increase GREM2 expression. Silencing of GREM2 blocked the effects of FOXA2. GREM2 increased LATS2 activity and YAP phosphorylation and degradation. To conclude, this study demonstrated that FOXA2 suppressed miR-103a-3p transcription to induce GREM2 upregulation, which increased LATS2 activity and YAP phosphorylation to inhibit migration and invasion of LC cells.

Bone Morphogenic Protein Signaling and Melanoma

OPINION STATEMENT

Malignant melanoma is a deadly form of skin cancer caused by neoplastic transformation of melanocytic cells. Despite recent progress in melanoma therapy, by inhibition of activated oncogenes or immunotherapy, survival rate for metastatic melanoma patients remains low. The remarkable phenotypic plasticity of melanoma cells allows for rapid development of invasive properties and metastatic tumors, the main cause of mortality in melanoma patients. Phenotypic and molecular analyses of developing tumors revealed that epithelial-mesenchymal transition (EMT), a cellular and molecular mechanism, controls transition from mature melanocyte to less differentiated melanocyte lineage progenitor cells forming melanoma tumors. This transition is facilitated by persistence of transcriptional regulatory circuit characteristic of embryonic stage in mature melanocytes. Switching of the developmental program of mature melanocyte to EMT is induced by accumulated mutations, especially targeting BRAF, N-RAS, or MEK1/2 signaling pathways, and further promoted by dynamic stimuli from local environment including hypoxia, interactions with extracellular matrix and growth factors or cytokines. Recent reports demonstrate that signaling mediated by transforming growth factor-β (TGF-β) and bone morphogenic proteins (BMPs) play critical roles in inducing EMT by controlling expression of critical transcription factors. BMPs are essential modulators of differentiation, proliferation, apoptosis, invasiveness, and metastases in developing melanoma tumors. They control transcription and epigenetic landscape of melanoma cells. Better understanding of the role of BMPs may lead to new strategies to control EMT processes in melanocyte cell lineage and to achieve clinical benefits for the patients.

XIAP's Profile in Human Cancer

XIAP, the X-linked inhibitor of apoptosis protein, regulates cell death signaling pathways through binding and inhibiting caspases. Mounting experimental research associated with XIAP has shown it to be a master regulator of cell death not only in apoptosis, but also in autophagy and necroptosis. As a vital decider on cell survival, XIAP is involved in the regulation of cancer initiation, promotion and progression. XIAP up-regulation occurs in many human diseases, resulting in a series of undesired effects such as raising the cellular tolerance to genetic lesions, inflammation and cytotoxicity. Hence, anti-tumor drugs targeting XIAP have become an important focus for cancer therapy research. RNA-XIAP interaction is a focus, which has enriched the general profile of XIAP regulation in human cancer. In this review, the basic functions of XIAP, its regulatory role in cancer, anti-XIAP drugs and recent findings about RNA-XIAP interactions are discussed.

Biomarkers for Pancreatic Neuroendocrine Neoplasms (PanNENs) Management-An Updated Review

Pancreatic neuroendocrine tumors (PanNENs) are rare sporadic cancers or develop as part of hereditary syndromes. PanNENs can be both functioning and non-functioning based on whether they produce bioactive peptides. Some PanNENs are well differentiated while others-poorly. Symptoms, thus, depend on both oncological and hormonal causes. PanNEN diagnosis and treatment benefit from and in some instances are guided by biomarker monitoring. However, plasmatic monoanalytes are only suggestive of PanNEN pathological status and their positivity is typically followed by deepen diagnostic analyses through imaging techniques. There is a strong need for new biomarkers and follow-up modalities aimed to improve the outcome of PanNEN patients. Liquid biopsy follow-up, i.e., sequential analysis on tumor biomarkers in body fluids offers a great potential, that need to be substantiated by additional studies focusing on the specific markers and the timing of the analyses. This review provides the most updated panorama on PanNEN biomarkers.

Autocrine BMP4 Signaling Enhances Tumor Aggressiveness via Promoting Wnt/β-Catenin Signaling in IDH1-mutant Gliomas

The isocitrate dehydrogenase (IDH1/2) mutations are frequent genetic abnormalities in the majority of WHO grade II/III glioma and secondary GBM. IDH1-mutated (IDH1^Mut) glioma exhibits distinctive patterns in cancer biology and metabolism. In the present study, we showed that bone morphogenetic proteins (BMP4) are significantly upregulated in IDH1^Mut glioma. Further, we demonstrated that cancer-associated BMP4 is secreted to tumor microenvironment, which enhances the tumor migration and invasion through an autocrine manner. Mechanistically, BMP4 activates its receptor and concomitant SMAD1/5/8 signaling, which potentiates Wnt/β-catenin signaling by enhancing Frizzled receptor expression. LDN-193189, a selective BMP receptor inhibitor, prolonged the overall survival of mice bearing IDH1-mutated intracranial xenografts by limiting BMP/catenin signaling. These findings demonstrate the pivotal role of BMP4 on tumor aggressiveness in IDH1^Mut gliomas, suggesting a possible therapeutic strategy for this type of malignancy.

Multifaceted roles of TAK1 signaling in cancer

Context-specific signaling is a prevalent theme in cancer biology wherein individual molecules and pathways can have multiple or even opposite effects depending on the tumor type. TAK1 represents a particularly notable example of such signaling diversity in cancer progression. Originally discovered as a TGF-β-activated kinase, over the years it has been shown to respond to numerous other stimuli to phosphorylate a wide range of downstream targets and elicit distinct cellular responses across cell and tissue types. Here we present a comprehensive review of TAK1 signaling and provide important therapeutic perspectives related to its function in different cancers.

Neuroendocrine neoplasms: current and potential diagnostic, predictive and prognostic markers

Some biomarkers for functioning and non-functioning neuroendocrine neoplasms (NENs) are currently available. Despite their application in clinical practice, results should be interpreted cautiously. Considering the variable sensitivity and specificity of these parameters, there is an unmet need for novel biomarkers to improve diagnosis and predict patient outcome. Nowadays, several new biomarkers are being evaluated and may become future tools for the management of NENs. These biomarkers include (1) peptides and growth factors; (2) DNA and RNA markers based on genomics analysis, for example, the so-called NET test, which has been developed for analyzing gene transcripts in circulating blood; (3) circulating tumor/endothelial/progenitor cells or cell-free tumor DNA, which represent minimally invasive methods that would provide additional information for monitoring treatment response and (4) improved imaging techniques with novel radiolabeled somatostatin analogs or peptides. Below we summarize some future directions in the development of novel diagnostic and predictive/prognostic biomarkers in NENs. This review is focused on circulating and selected tissue markers.

Role of miR-486-5p in regulating renal cell carcinoma cell proliferation and apoptosis via TGF-β-activated kinase 1

Renal cell carcinoma (RCC) is a common kidney tumor in adults. The role of miR-486-5p in RCC is unknown. The aim of our study was to identify new targets regulated by miR-486-5p in RCC, to obtain a deeper insight into the network and to better understand the role of these microRNAs and their targets in carcinogenesis of RCC. We performed a series of tests and found consistently lower expression levels of miR-486-5p in kidney cancer cells. Restoration of miR-486-5p expression in RCC cells could lead to the suppression of cell proliferation and the increase of cell apoptosis. Further studies demonstrated that TGF-β-activated kinase 1 was a target gene of miR-486-5p in kidney cancer cells. It was also shown that C-C motif chemokine ligand 2 (CCL2) from tumor-associated macrophages downregulated miR-486-5p expression, and miR-486-5p inhibited RCC cell proliferation and apoptosis resistance induced by CCL2. The study demonstrates that there are potential diagnosis and therapy values of miR-486-5p in RCC.

NF-κB/MAPK activation underlies ACVR1-mediated inflammation in human heterotopic ossification

BACKGROUND

Inflammation helps regulate normal growth and tissue repair. Although bone morphogenetic proteins (BMPs) and inflammation are known contributors to abnormal bone formation, how these pathways interact in ossification remains unclear.

METHODS

We examined this potential link in patients with fibrodysplasia ossificans progressiva (FOP), a genetic condition of progressive heterotopic ossification caused by activating mutations in the Activin A type I receptor (ACVR1/ALK2). FOP patients show exquisite sensitivity to trauma, suggesting that BMP pathway activation may alter immune responses. We studied primary blood, monocyte, and macrophage samples from control and FOP subjects using multiplex cytokine, gene expression, and protein analyses; examined CD14+ primary monocyte and macrophage responses to TLR ligands; and assayed BMP, TGF-β activated kinase 1 (TAK1), and NF-κB pathways.

RESULTS

FOP subjects at baseline without clinically evident heterotopic ossification showed increased serum IL-3, IL-7, IL-8, and IL-10. CD14+ primary monocytes treated with the TLR4 activator LPS showed increased CCL5, CCR7, and CXCL10; abnormal cytokine/chemokine secretion; and prolonged activation of the NF-κB pathway. FOP macrophages derived from primary monocytes also showed abnormal cytokine/chemokine secretion, increased TGF-β production, and p38MAPK activation. Surprisingly, SMAD phosphorylation was not significantly changed in the FOP monocytes/macrophages.

CONCLUSIONS

Abnormal ACVR1 activity causes a proinflammatory state via increased NF-κB and p38MAPK activity. Similar changes may contribute to other types of heterotopic ossification, such as in scleroderma and dermatomyositis; after trauma; or with recombinant BMP-induced bone fusion. Our findings suggest that chronic antiinflammatory treatment may be useful for heterotopic ossification.

Double-Humanized Mouse Model to Study Bone Morphogenetic Protein (BMP) Signaling in Tumor Xenografts

The activation of the bone morphogenic protein (BMP) signaling pathway in cancer cells has been shown to enhance migration and tumor angiogenesis and promote survival. The BMP signaling pathway regulates benign cells in the tumor microenvironment and is a known regulator of immune cells. The development of BMP receptor inhibitors has allowed the study of tumor xenografts in mice. We describe a double-humanized mouse model with adoptively transferred human immune and human tumor cells that can be used to assess the effects of BMP inhibitors on these human cells in vivo.

Novel bone morphogenetic protein receptor inhibitor JL5 suppresses tumor cell survival signaling and induces regression of human lung cancer

BMP receptor inhibitors induce death of cancer cells through the downregulation of antiapoptotic proteins XIAP, pTAK1, and Id1-Id3. However, the current most potent BMP receptor inhibitor, DMH2, does not downregulate BMP signaling in vivo because of metabolic instability and poor pharmacokinetics. Here we identified the site of metabolic instability of DMH2 and designed a novel BMP receptor inhibitor, JL5. We show that JL5 has a greater volume of distribution and suppresses the expression of Id1 and pTak1 in tumor xenografts. Moreover, we demonstrate JL5-induced tumor cell death and tumor regression in xenograft mouse models without immune cells and humanized with adoptively transferred human immune cells. In humanized mice, JL5 additionally induces the infiltration of immune cells within the tumor microenvironment. Our studies show that the BMP signaling pathway is targetable in vivo and BMP receptor inhibitors can be developed as a therapeutic to treat cancer patients.

Connective tissue growth factor-specific monoclonal antibody inhibits growth of malignant mesothelioma in an orthotopic mouse model

Malignant mesothelioma is an aggressive neoplasm with no particularly effective treatments. We previously reported that overexpression of connective tissue growth factor (CTGF/CCN2) promotes mesothelioma growth, thus suggesting it as a novel molecular target. A human monoclonal antibody that antagonizes CTGF (FG-3019, pamrevlumab) attenuates malignant properties of different kinds of human cancers and is currently under clinical trial for the treatment of pancreatic cancer. This study reports the effects of FG-3019 on human mesothelioma in vitro and in vivo. We analyzed the effects of FG-3019 on the proliferation, apoptosis, migration/invasion, adhesion and anchorage-independent growth in three human mesothelioma cell lines, among which ACC-MESO-4 was most efficiently blocked with FG-3019 and was chosen for in vivo experiments. We also evaluated the coexistent effects of fibroblasts on mesothelioma in vitro, which are also known to produce CTGF in various pathologic situations. Coexistent fibroblasts in transwell systems remarkably promoted the proliferation and migration/invasion of mesothelioma cells. In orthotopic nude mice model, FG-3019 significantly inhibited mesothelioma growth. Histological analyses revealed that FG-3019 not only inhibited the proliferation but also induced apoptosis in both mesothelioma cells and fibroblasts. Our data suggest that FG-3019 antibody therapy could be a novel additional choice for the treatment of mesothelioma.

Long noncoding RNA hypoxia-inducible factor 1 alpha-antisense RNA 1 promotes tumor necrosis factor-α-induced apoptosis through caspase 3 in Kupffer cells

Kupffer cells (KCs) play a crucial role in the pathogenesis of acute-on-chronic liver failure (ACLF) which is characterized by acute and severe disease in patients with preexisting liver disease and shows high mortality. Long noncoding RNAs (lncRNAs) are recently found to be involved in gene regulation. However, the mechanisms of how KCs are regulated by inflammatory factors, tumor necrosis factor-α (TNF-α), and whether lncRNAs are involved in the process remain largely unknown. Hence, we investigated the role of lncRNAs in the cytotoxicity of TNF-α on KCs.lncRNA array (The lncRNAs in the array are apoptosis-related lncRNAs reported in some research papers.) was used to identify lncRNAs related with liver fibrosis. Annexin V/protease inhibitor (PI) staining was used for detection of cell apoptosis. Real time-polymerase chain reaction was utilized for analysis of mRNA levels of lncRNA hypoxia-inducible factor 1 alpha-antisense RNA 1 (HIF1A-AS1) and apoptosis-related genes. Western blot was implied to the determination of lymphoid enhancer factor-1 (LEF-1).In this study, we found that HIF1A-AS1 could be upregulated by TNF-α by lncRNA array analysis and knockdown of HIF1A-AS1 significantly rescued cell apoptosis induced by TNF-α. Moreover, inhibition of HIF1A-AS1 markedly reduced mRNA level of caspase 3 which can be significantly enhanced by TNF-α. Furthermore, HIF1A-AS1 showed binding sites for LEF-1 and siRNA-mediated downregulation of LEF-1 decreased HIF1A-AS1 level in KCs treated with TNF-α.This study elucidates a new role of HIF1A-AS1 in TNF-α-induced cell apoptosis and provides potential therapeutic targets for ACLF.

NG25, an inhibitor of transforming growth factor‑β‑activated kinase 1, ameliorates neuronal apoptosis in neonatal hypoxic‑ischemic rats

Transforming growth factor (TGF)-β-activated kinase 1 (TAK1) was found to be activated by TGF-β and acts as a central regulator of cell death in various types of disease. However, the expression and function of TAK1 in the neonatal brain following hypoxia-ischemia (HI) remains unclear. In the present study, western blotting and immunofluorescence were employed to determine the expression and distribution of TAK1 in the brain cortex of a perinatal HI rat model. In addition, the specific inhibitor of TAK1, NG25 was administered via intracerebroventricular injection, prior to insult of the neonatal rat brains, for neuroprotection. Western blotting and double immunofluorescence indicated that an increased expression level of phosphorylated-TAK1 was observed, and was localized with neurons and astrocytes, compared with the sham group. Further study demonstrated that injection of NG25 prior to insult significantly inhibited TAK1/c-Jun N-terminal kinases activity and dramatically ameliorated acute hypoxic-ischemic cerebral injury by inhibiting cell apoptosis in perinatal rats. Thus, NG25 ameliorates neuronal apoptosis in neonatal HI rats by inhibiting TAK1 expression and cell apoptosis. In addition, NG25 may serve as a promising novel neuroprotective inhibitor for perinatal cerebral injury.

KLF15 promotes the proliferation and metastasis of lung adenocarcinoma cells and has potential as a cancer prognostic marker

Lung adenocarcinoma (LADC)is a general form of non-small cell lung cancer that represents a significant threat to public health worldwide. The 5-year-survival rate for LADC is currently below 15%. The transcription factor KLF15, also called kidney-enriched KLF (KKLF), has been proven to play a role in inhibiting proliferation and diversification of carcinoma cells, including those of the endometrium, pancreas and breast, but the involvement of KLF15 in LADC has not previously been studied. In this study, we compared the in vitro expression of KLF15 in human LADC tissues and adjacent normal lung tissues. Expression of KLF15 was found to be abnormally high in LADC tissues and cells compared with adjacent non-tumorous tissues, and was correlated with tumor TNM stage and tumor differentiation (P = 0.003, P = 0.001, respectively). The effect of KLF15 on cell growth and migration were explored in vitro by Western Blotting, CCK8 and colony formation assays, flow cytometry analysis and transwell migration assays, and in vivo by analysis of tumorigenesis in 5-week old BALB/c nude mice. Knockdown of KLF15 significantly upregulated the protein levels of cleaved caspase-3, caspase-7, caspase-8 and PARP, thereby inducing apoptosis. Downregulation of KLF15 in A549 and NCI-H1650 cell lines resulted in these cell lines exhibiting markedly slower growth rates when injected subcutaneously into the flank of nude mice, compared with the comparator control groups (P < 0.05). Collectively, our findings suggest that KLF15 may have a significant effect on LADC cell survival, and that it represents a potential therapeutic and preventive biomarker for LADC prognosis and treatment.

[Relationship between ID1 and EGFR-TKI Resistance in Non-small Cell Lung Cancer]

背景与目的

非小细胞肺癌(non-small cell lung cancer, NSCLC)是当今世界上发病率和死亡率最高的恶性肿瘤之一，而表皮生长因子受体-酪氨酸激酶抑制剂(epidermal growth factor receptor-tyrosine kinase inhibitors, EGFR-TKI)整体有效率为30%-40%，无进展生存期(progression-free survival, PFS)为12个月。但EGFR-TKI在临床中的耐药现象也很普遍，严重影响了其抑瘤作用。因此，克服耐药、寻找一种新的与肺癌耐药相关的预后因子势在必行。本研究旨在通过体内外实验探讨DNA结合抑制因子1(differentiation inhibitory factor 1, ID1)与NSCLCEGFR-TKI耐药之间的关系，看其是否有统计学意义，并初步探讨其机制。

方法

免疫组化(immunohistochemistry, IHC)检测手术标本(肺癌组织和癌旁组织)1D1的表达；qRT-PCR、Western-blot检测并比较肺癌细胞敏感株与耐药株中ID1的表达变化；MTT检测吉非替尼对ID1慢病毒载体处理肺癌细胞的细胞增殖情况，将肺癌细胞接种至裸鼠腋下，待肿瘤生长至一定体积使用吉非替尼治疗，估算肿瘤体积。

结果

ID1在肺癌组织中的表达明显高于正常组织(P < 0.05)；ID1的表达与NSCLC EGFR-TKI耐药呈正相关(P < 0.05)。

结论

ID1在NSCLC中高表达，并且参与了NSCLC EGFR-TKI的耐药，其机制可能与STAT3磷酸化程度增加有关。

Bone morphogenetic protein 2 (BMP2) induces growth suppression and enhances chemosensitivity of human colon cancer cells

BACKGROUND

Molecular profiling of colorectal cancer (CRC) based on global gene expression has revealed multiple dysregulated signalling pathways associated with drug resistance and poor prognosis. However, the role of BMP2 signaling in CRC is not fully characterised.

METHODS

Bioinformatics data analysis were conducted on the GSE21510 dataset. Leniviral technology was utilized to stably express BMP2 in the HCT116 CRC model. Gene expression profiling was conducted using Agilent microarray platform while data normalization and bioinformatics were conducted using GeneSpring software. Changes in gene expression were assessed using qRT-PCR. AlamarBlue assay was used to assess cell viability in vitro. In vivo experiments were conducted using SCID mice.

RESULTS

Our data revealed frequent downregulation of BMP2 in primary CRC tissues. Additionally, interrogation of publically available gene expression datasets revealed significant downregulation of BMP2 in metastatic recurrent compared to non-metastatic cancer (p = 0.02). Global gene expression analysis in CRC cells over-expressing BMP2 revealed multiple dysregulated pathways mostly affecting cell cycle and DNA damage response. Concordantly, lentiviral-mediated re-expression of BMP2 inhibited HCT116 CRC growth, sphere formation, clonogenic potential, cell migration, and sensitized CRC cells to 5-fluorouracil (5-FU) in vitro. Additionally, BMP2 inhibited CRC tumor formation in SCID mice.

CONCLUSIONS

Our data revealed an inhibitory role for BMP2 in CRC, suggesting that restoration of BMP2 expression could be a potential therapeutic strategy for CRC.