STAT3 as a target for inducing apoptosis in solid and hematological tumors. Cell Res. 2008;18:254-267. [PMID: 18227858 DOI: 10.1038/cr.2008.18]

Cyclosporine A Downregulates Selenoprotein P Expression via a Signal Transducer and Activator of Transcription 3-Forkhead Box Protein O1 Pathway in Hepatocytes In Vitro

Cyclosporine A (CsA) is an immunosuppressant applied worldwide for preventing graft rejection and autoimmune diseases. However, CsA elevates oxidative stress, which can lead to liver injuries. The present study aimed to clarify the mechanisms underlying the CsA-mediated oxidative stress. Among the redox proteins, CsA concentration-dependently downregulated Selenop-encoding selenoprotein P, a major circulating antioxidant protein reducing reactive oxygen species, in hepatocytes cell lines and primary hepatocytes. The luciferase assay identified the CsA-responsive element in the SELENOP promoter containing a putative binding site for forkhead box protein O (FoxO) 1. The CsA-mediated suppression on the SELENOP promoter was independent of the nuclear factor of activated T-cell, a classic target repressed by CsA. A chromatin immunoprecipitation assay showed that CsA suppressed the FoxO1 binding to the SELENOP promoter. Foxo1 knockdown significantly downregulated Selenop expression in H4IIEC3 cells. Furthermore, CsA downregulated FoxO1 by inactivating its upstream signal transducer and activator of transcription 3 (STAT3). Knockdown of Stat3 downregulated Foxo1 and Selenop expression in hepatocytes. These findings revealed a novel mechanism underlying CsA-induced oxidative stress by downregulating the STAT3-FoxO1-Selenop pathway in hepatocytes. SIGNIFICANCE STATEMENT: This study shows that Cyclosporine A (CsA) downregulates Selenop, an antioxidant protein, by suppressing the signal transducer and activator of transcription 3-forkhead box protein O1 pathway in hepatocytes, possibly one of the causations of CsA-induced oxidative stress in hepatocytes. The present study sheds light on the previously unrecognized CsA-redox axis.

Triphlorethol-A attenuates U251 human glioma cancer cell proliferation and ameliorates apoptosis through JAK2/STAT3 and p38 MAPK/ERK signaling pathways

Glioma is the foremost recurrent type of brain tumor in humans; in particular, glioblastoma (GBM) is the main form of brain tumor (GBM) that is highly proliferative and impervious to apoptosis. Triphlorethol-A (TA), a phlorotannin isolated from Ecklonia cava, exhibited cytoprotective, antioxidant, and anticancer properties. However, the exact molecular action of TA in the U251 human GBM cells remains unknown. This may be the first report on the antiproliferative and apoptotic mechanisms of TA on GBM. The cytotoxicity, intracellular reactive oxygen species (ROS), matrix metalloproteinase (MMP), and cell apoptosis activity of TA have been evaluated by the MTT assay and by DCFH-DA, Rh-123, AO/EB, and western blot analysis. The results obtained showed that TA abridged the viability of U251 cells, while MMP increased apoptosis by increasing the ROS levels in a time-dependent manner. The results showed that a reduction in U251 cell proliferation was associated with the regulation of JAK2/STAT3 and p38 MAPK/ERK signaling pathways. TA was found to suppress pJAK, pSTAT3, p38 MAPK, and pERK phosphorylation, thereby causing Bax/Bcl-2 imbalance, activating the caspase cascade and cytochrome c, and inducing apoptosis. Our findings showed that the suppression of JAK2/STAT3 and p38 MAPK/ERK signaling by TA results in cell growth arrest and stimulation of apoptosis in GBM cells. These studies justify the protective remedy of TA against GBM.

Direct knockdown of phospho-PTM targets mediated by TRIM21 can improve personalized treatment in breast cancer

PURPOSE

In this work for the first time, we showed specific and direct knockdown of important oncogenic proteins of interest and their phospho-PTM targets in tripartite motif containing-21 (TRIM21) overexpressing breast cancer (BC) cells. We revealed the functional and therapeutic consequences of this protein knockdown approach called 'TRIM-ing'.

METHODS

To target HER2, HER3, STAT3 or their activated forms, electroporation and puls-in transfection were standardized for mAb delivery in AU565 and MCF7 BC cell lines. Cancer cells were treated with HER2-targeted medicines (Trastuzumab and Neratinib) or STAT3 targeted inhibitors (Stattic and Niclosamide) with or without respective target TRIM-ing. Real-time PCR, immunoblotting, immunofluorescence, cytotoxicity, short- and long-term cell survival assessments were done following standard methodologies. 3-D structure modelling was used to verify the binding of mAb onto the STAT3 target.

RESULTS

TRIM-ing of HER2 or HER3 receptors or their activated phospho-forms in BC cells showed rapid degradation of respective protein forms, shattering down the downstream signaling (p-ERK, p-AKT) that lasts for up to 7-8 days. This significantly inhibited BC survival (p < 0.001), showing a synergistic therapeutic effect with HER2 medicine trastuzumab or neratinib. Additionally, specific TRIM-ing ability of canonical pY705 or non-canonical pS727 PTMs of STAT3 protein was demonstrated in MCF7 cells, causing significant cytotoxicity (p < 0.05). TRIM-ing of STAT3 PTM, when combined with the same PTM-specific inhibitors, a synergistic treatment effect was observed.

CONCLUSION

The work demonstrated that TRIM-ing could directly reduce various oncogenic targets or their specific activated form inside the cancer cells without compensatory pathway activation, a conundrum limiting the therapeutic benefit of current personalized medicines.

Targeting the transcriptional activity of STAT3 by a novel fusion protein

BACKGROUND

The continuous activation of transcription factors drives many diseases, including tumors, autoimmune disease, neurodegenerative disease, and male infertility. Thus, Blocking the transcriptional activity of these proteins may inhibit disease progression. In this study, we developed a new method to specifically inhibit the activity of the transcription factor STAT3.

METHODS

Fusing the transcriptional inhibitory domain KRAB with STAT3 successfully blocked the transcription activity of STAT3 in cancer cells without affecting its function in the mitochondria and lysosomes.

RESULTS

the expression of KRAB-STAT3 fusion protein inhibited the growth of tumor cells.

CONCLUSIONS

The KRAB-STAT3 fusion protein provides a novel approach for drug development for the treatment of cancer or autoimmune diseases.

Acute myeloid leukemia cell-derived extracellular vesicles carrying microRNA-548ac regulate hematopoietic function via the TRIM28/STAT3 pathway

microRNAs (miRNAs or miRs) can be delivered from acute myeloid leukemia (AML) cells to hematopoietic stem cells (HSCs) to regulate hematopoietic function via extracellular vesicles (EVs). In this study, we investigated the roles played by EVs that transport miR-548ac from AML cells in normal hematopoiesis. Bioinformatics analysis demonstrated that miR-548ac was highly expressed in AML-derived EVs. The expression of miR-548ac and TRIM28 and the targeting relationship were identified, and the results demonstrated that the expression of miR-548ac was upregulated in AML cell lines and AML cell-secreted EVs compared with CD34⁺ HSCs. AML-derived EVs targeted CD34⁺ HSCs to induce decreased expression of TRIM28 and downstream activation of STAT3. Exosomal miR-548ac was transferred into CD34⁺ HSCs to target TRIM28. Through gain- and loss-of-function assays, it was observed that the abrogated expression of miR-548ac or STAT3 promoted colony-forming units (CFU), whereas overexpressed miR-548ac repressed CFU, which was rescued by overexpression of TRIM28. Taken together, these results indicated that miR-548ac delivered by AML cell-derived EVs inhibits hematopoiesis via TRIM28-dependent STAT3 activation.

Cyclosporine A downregulates selenoprotein P expression via a STAT3-FoxO1 pathway in hepatocytes in vitro

Cyclosporine A (CsA) is a worldwide applied immunosuppressant for preventing graft rejection and autoimmune diseases. However, CsA elevates oxidative stress leading to liver injuries. The present study aimed to clarify the mechanisms underlying the CsA-mediated oxidative stress. Among the redox proteins, CsA concentration-dependently downregulated Selenop encoding selenoprotein P (SeP), a major circulating antioxidant protein reducing reactive oxygen species (ROS), in hepatocytes cell lines and primary hepatocytes. The luciferase assay identified the CsA-responsive element in the SELENOP promoter containing a putative binding site for FoxO1. The CsA-mediated suppression on the SELENOP promoter was independent of NFAT, a classic target repressed by CsA. A ChIP assay showed that CsA suppressed the FoxO1 binding to the SELENOP promoter. Foxo1 knockdown significantly downregulated Selenop expression in H4IIEC3 cells. Furthermore, CsA downregulated FoxO1 by inactivating its upstream signal transducer and activator of transcription 3 (STAT3). Knockdown of Stat3 downregulated Foxo1 and Selenop expression in hepatocytes. These findings revealed a novel mechanism underlying CsA-induced oxidative stress via downregulating the STAT3-FoxO1-Selenop pathway in hepatocytes. Significance Statement Our study shows that CsA downregulates Selenop, an antioxidant protein, via suppressing the STAT3-FoxO1 pathway in hepatocytes, possibly one of the causations of CsA-induced oxidative stress in hepatocytes. The present study sheds light on the previously unrecognized CsA-redox axis.

Progesterone receptor expression contributes to gemcitabine resistance at higher ECM stiffness in breast cancer cell lines

Chemoresistance poses a great barrier to breast cancer treatment and is thought to correlate with increased matrix stiffness. We developed two-dimensional (2D) polyacrylamide (PAA) and three-dimensional (3D) alginate in vitro models of tissue stiffness that mimic the stiffness of normal breast and breast cancer. We then used these to compare cell viability in response to chemotherapeutic treatment. In both 2D and 3D we observed that breast cancer cell growth and size was increased at a higher stiffness corresponding to tumours compared to normal tissue. When chemotherapeutic response was measured, a specific differential response in cell viability was observed for gemcitabine in 2 of the 7 breast cancer cell lines investigated. MCF7 and T-47D cell lines showed gemcitabine resistance at 4 kPa compared to 500 Pa. These cell lines share a common phenotype of progesterone receptor (PGR) expression and, indeed, pre-treatment with the selective progesterone receptor modulator (SPRM) mifepristone abolished resistance to gemcitabine at high stiffness. Our data reveals that combined treatment with SPRMs may therefore help in reducing resistance to gemcitabine in stiffer breast tumours which are PGR positive.

Radotinib inhibits multiple myeloma cell proliferation via suppression of STAT3 signaling

Multiple myeloma (MM) is a hematological cancer causing from accumulated abnormal plasma cells. STAT3 overexpression in MM appears to be mediated by a variety of factors, and it may be associated with an adverse prognosis and play a role in microenvironment-dependent treatment resistance. Unfortunately, MM remains an incurable disease, as relapse is very common. Therefore, there is urgent need to develop new treatment options for MM. Radotinib is a novel anti-cancer drug, currently approved in South Korea for the treatment of chronic myeloid leukemia patients. It is an oral, multitargeted inhibitor of receptor tyrosine kinases, including BCR-ABL, c-KIT, PDGFR, and Src family kinases. However, little is known about the effects of radotinib on multiple myeloma cells. However, little is known about the effects of radotinib on multiple myeloma cells. But even tinip almost not known about the impact of multiple myeloma cells. Moreover, nothing is known about how it affects STAT3 and JAK2. In this study, we analyzed the effect of radotinib on multiple myeloma cells. Herein, Moreover, nothing is known about how it. Moreover, not all is known about how the affects STAT3 and JAK2. We investigated the effect of radotinib on the STAT3 signaling pathway in MM cells, including several MM cell lines and mouse models. So we investigated the effect of radotinib on MM cells, including several MM cell lines and mouse models. Interestingly, radotinib induced apoptosis, and inhibited cell proliferation in MM cells including RPMI-8226, MM.1S, U266B1, and IM-9 cells. Moreover, radotinib treatment significantly increased the number Annexin V-positive cells and G0/G1-phase cells. In addition, radotinib treatment in various MM cells strongly suppressed the activity and expression of STAT3 and JAK2 proteins. We also observed that diverse proteins related to the STAT3 signaling pathway, including c-Myc, Bcl-xL, Mcl-1, cyclin D1 and cyclin D3, were powerfully inhibited by radotinib treatment in MM cells. Furthermore, radotinib significantly suppressed MM cell growth in a xenograft animal model using IM-9 cells. In conclusion, radotinib may play an important role as a candidate agent for MM treatment.

Hypoxia as a Modulator of Inflammation and Immune Response in Cancer

A clear association between hypoxia and cancer has heretofore been established; however, it has not been completely developed. In this sense, the understanding of the tumoral microenvironment is critical to dissect the complexity of cancer, including the reduction in oxygen distribution inside the tumoral mass, defined as tumoral hypoxia. Moreover, hypoxia not only influences the tumoral cells but also the surrounding cells, including those related to the inflammatory processes. In this review, we analyze the participation of HIF, NF-κB, and STAT signaling pathways as the main components that interconnect hypoxia and immune response and how they modulate tumoral growth. In addition, we closely examine the participation of the immune cells and how they are affected by hypoxia, the effects of the progression of cancer, and some innovative applications that take advantage of this knowledge, to suggest potential therapies. Therefore, we contribute to the understanding of the complexity of cancer to propose innovative therapeutic strategies in the future.

Platycodon grandiflorum Triggers Antitumor Immunity by Restricting PD-1 Expression of CD8+ T Cells in Local Tumor Microenvironment

In the tumor microenvironment (TME), the activation of programmed death-1 (PD-1)–programmed death ligand-1 (PD-L1) pathway is one of the main signals of immune escape and tumor deterioration. Clinically, the application of monoclonal antibodies slows down the progression of various malignancies and prolongs the survival of patients effectively. However, these treatments result in serious immune-related adverse events (irAEs) owning to systemic immune activation. Therefore, to achieve long-term therapeutic effects and low side effects, it is necessary to find drugs inhibiting the local PD-1/PD-L1 signaling pathway of the TME. Here, we discovered that Platycodon grandiflorum (PG), a medicine and food homology herb, reduced the expression of PD-1 on the surface of CD8⁺ T cells to exert antitumor effects in non-small cell lung cancer (NSCLC). Firstly, by combining systems pharmacology strategies and clinical data analysis, we found that PG has the potential to immunomodulate T cells and suppress tumors. Secondly, in vivo and in vitro experiments have confirmed the antitumor effect of the combination of Platycodin D and Platycodin D3, which is preferred and representative of the compounds. Mechanistically, PG increased the infiltration and killing activity of CD8⁺ T cells, which was related to the decrease of PD-1⁺ CD8⁺ T cells. Furthermore, we confirmed that PG regulated the expression of PD-1 on the surface of CD8⁺ T cells via reducing the secretion of VEGF-A regulated by the level of P-STAT3 in tumor cells. Additionally, PG also positively impacted the biological processes downstream of STAT3. Overall, we demonstrated that PG-mediated downregulation of PD-1 on the surface of CD8⁺ T cells represents a promising strategy to locally enhance T-cell responses and improve antitumor immunity.

Heme Oxygenase-1 targeting exosomes for temozolomide resistant glioblastoma synergistic therapy

Glioblastoma (GBM) is a highly fatal and recurrent brain cancer without a complete prevailing remedy. Although the synthetic nanotechnology-based approaches exhibit excellent therapeutic potential, the associated cytotoxic effects and organ clearance failure rest major obstacles from bench to clinics. Here, we explored allogeneic bone marrow mesenchymal stem cells isolated exosomes (BMSC_Exo) decorated with heme oxygenase-1 (HMOX1) specific short peptide (HSSP) as temozolomide (TMZ) and small interfering RNA (siRNA) nanocarrier for TMZ resistant glioblastoma therapy. The BMSC_Exo had excellent TMZ and siRNA loading ability and could traverse the blood-brain barrier (BBB) by leveraging its intrinsic brain accumulation property. Notably, with HSSP decoration, the TMZ or siRNA encapsulated BMSC_Exo exhibited excellent TMZ resistant GBM targeting ability both in vitro and in vivo due to the overexpression of HMOX1 in TMZ resistant GBM cells. Further, the HSSP decorated BMSC_Exo delivered the STAT3 targeted siRNA to the TMZ resistant glioma and restore the TMZ sensitivity, consequently achieved the synergistically drug resistant GBM treatment with TMZ. Our results showed this biomimetic nanoplatform can serve as a flexible, robust and inert system for GBM treatment, especially emphasizing the drug resistant challenge.

Nobiletin as an inducer of programmed cell death in cancer: a review

Cancer resistance to therapy is a big issue in cancer therapy. Tumours may develop some mechanisms to reduce the induction of cell death, thus stimulating tumour growth. Cancer cells may show a low expression and activity of tumour suppressor genes and a low response to anti-tumour immunity. These mutations can increase the resistance of cancer cells to programmed cell death mechanisms such as apoptosis, ferroptosis, pyroptosis, autophagic cell death, and some others. The upregulation of some mediators and transcription factors such as Akt, nuclear factor of κB, signal transducer and activator of transcription 3, Bcl-2, and others can inhibit cell death in cancer cells. Using adjuvants to induce the killing of cancer cells is an interesting strategy in cancer therapy. Nobiletin (NOB) is a herbal-derived agent with fascinating anti-cancer properties. It has been shown to induce the generation of endogenous ROS by cancer cells, leading to damage to critical macromolecules and finally cell death. NOB may induce the activity of p53 and pro-apoptosis mediators, and also inhibit the expression and nuclear translocation of anti-apoptosis mediators. In addition, NOB may induce cancer cell killing by modulating other mechanisms that are involved in programmed cell death mechanisms. This review aims to discuss the cellular and molecular mechanisms of the programmed cell death in cancer by NOB via modulating different types of cell death in cancer.

Elaeagnus angustifolia Plant Extract Induces Apoptosis via P53 and Signal Transducer and Activator of Transcription 3 Signaling Pathways in Triple-Negative Breast Cancer Cells

Elaeagnus angustifolia (EA) is used as an alternative medicine in the Middle East to manage numerous human diseases. We recently reported that EA flower extract inhibits cell proliferation and invasion of human oral and HER2-positive breast cancer cells. Nevertheless, the outcome of EA extract on triple-negative breast cancer (TNBC) cells has not been explored yet. We herein investigate the effect of the aqueous EA extract (100 and 200 μl/ml) on two TNBC cell lines (MDA-MB-231 and MDA-MB-436) for 48 h and explore its underlying molecular pathways. Our data revealed that EA extract suppresses cell proliferation by approximately 50% and alters cell-cycle progression of these two cancer cell lines. Additionally, EA extract induces cell apoptosis by 40–50%, accompanied by the upregulation of pro-apoptotic markers (Bax and cleaved caspase-8) and downregulation of the anti-apoptotic marker, Bcl-2. Moreover, EA extract inhibits colony formation compared to their matched control. More significantly, the molecular pathway analysis of EA-treated cells revealed that EA extract enhances p53 expression, while inhibiting the expression of total and phosphorylated Signal Transducer and Activator Of Transcription 3 (STAT3) in both cell lines, suggesting p53 and STAT3 are the main key players behind the biological events provoked by the extract in TNBC cells. Our findings implicate that EA flower extract may possess an important potential as an anticancer drug against TNBC.

Functionalized LbL Film for Localized Delivery of STAT3 siRNA and Oxaliplatin Combination to Treat Colon Cancer

The aim of the study was to develop and evaluate the efficacy of a functionalized layer-by-layer (LbL) assembled film entrapped with oxaliplatin (OX) and signal transducer and activator of transcription 3 (STAT3) siRNA in the localized treatment of colon cancer. The LbL film was prepared by the sequential layering of chitosan (CS) and alginate to attain desired physical and mechanical properties. The film was functionalized by coating folic acid-conjugated CS on one side. On the other side, polycaprolactone was coated as a backing layer to provide directional drug release. OX was entrapped within the layers of the film, while STAT3 siRNA was complexed with CS to form nanoparticles before entrapment in the LbL film. The CS-siRNA nanoparticles were taken up by the colon carcinoma, Caco-2 cells within 3 h and provided concentration-dependent reduction in STAT3 protein expression. The functionalized LbL film (F-LbL film) selectively adhered to the colon cancer tissue in the mice model, whereas the nonfunctionalized film adhered to the normal colon tissue. The combination of OX and STAT3 siRNA provided significantly greater tumor regression, survival rate, and STAT3 protein suppression after localized delivery through oral administration compared with intravenous administration. Taken together, the F-LbL film can selectively bind to colon tumors for localized delivery of drugs to treat colon cancer.

Holistic View of ALK TKI Resistance in ALK-Positive Anaplastic Large Cell Lymphoma

Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase expressed at early stages of normal development and in various cancers including ALK-positive anaplastic large cell lymphoma (ALK+ ALCL), in which it is the main therapeutic target. ALK tyrosine kinase inhibitors (ALK TKIs) have greatly improved the prognosis of ALK+ALCL patients, but the emergence of drug resistance is inevitable and limits the applicability of these drugs. Although various mechanisms of resistance have been elucidated, the problem persists and there have been relatively few relevant clinical studies. This review describes research progress on ALK+ ALCL including the application and development of new therapies, especially in relation to drug resistance. We also propose potential treatment strategies based on current knowledge to inform the design of future clinical trials.

Role of JAK2/STAT3 Signaling Pathway in the Tumorigenesis, Chemotherapy Resistance, and Treatment of Solid Tumors: A Systemic Review

Janus kinase 2/signal transducer and activator of transcription 3 (JAK2/STAT3) pathway is a common signaling pathway used to transduce signals from the extracellular to the intracellular (nucleus) upon the binding of cytokines and growth factors to the extracellular domain of specific cell surface receptors. This signaling pathway is tightly regulated and has a multitude of biological functions such as cell proliferation, differentiation, and apoptosis. Besides, the regulated JAK2/STAT3 signaling plays a crucial role in embryonic development, hemopoiesis, and controlling the immune system. Conversely, aberrantly activated JAK2/STAT3 is frequently detected in varieties of tumors and involved in oncogenesis, angiogenesis, and metastasis of many cancer diseases that are usually refractory to the standard chemotherapy. However, the JAK3/STAT3 pathway recently emerged interestingly as a new site for the development of novel anti-tumor agents and becomes a promising therapeutic target in the treatment of many solid malignancies. Herein, this review aimed to provide insight into the JAK2/STAT3 pathway, in the hope to gain an understanding of its potential role in the pathogenesis, progression, chemotherapy resistance, and cancer therapy of solid tumors.

Neutrophil Death in Myeloproliferative Neoplasms: Shedding More Light on Neutrophils as a Pathogenic Link to Chronic Inflammation

Neutrophils are an essential component of the innate immune response, but their prolonged activation can lead to chronic inflammation. Consequently, neutrophil homeostasis is tightly regulated through balance between granulopoiesis and clearance of dying cells. The bone marrow is both a site of neutrophil production and the place they return to and die. Myeloproliferative neoplasms (MPN) are clonal hematopoietic disorders characterized by the mutations in three types of molecular markers, with emphasis on Janus kinase 2 gene mutation (JAK2V617F). The MPN bone marrow stem cell niche is a site of chronic inflammation, with commonly increased cells of myeloid lineage, including neutrophils. The MPN neutrophils are characterized by the upregulation of JAK target genes. Additionally, MPN neutrophils display malignant nature, they are in a state of activation, and with deregulated apoptotic machinery. In other words, neutrophils deserve to be placed in the midst of major events in MPN. Our crucial interest in this review is better understanding of how neutrophils die in MPN mirrored by defects in apoptosis and to what possible extent they can contribute to MPN pathophysiology. We tend to expect that reduced neutrophil apoptosis will establish a pathogenic link to chronic inflammation in MPN.

Osteosarcoma cell proliferation suppression via SHP-2-mediated inactivation of the JAK/STAT3 pathway by tubocapsenolide A

Introduction

Previously, we have reported a withanolide-type steroid, named tubocapsenolide A (TA), which shows potent anti-proliferative activity in several cancer cell lines. However, its inhibitory effect on the Janus kinase/signal transducer and activator of transcription 3 (JAK/STAT3) pathway and therapeutic potential on osteosarcoma have not been reported.

Objectives

In the present study, we aimed to investigate the effect and molecular mechanism of TA in osteosarcoma.

Methods

The biological functions of TA in U2OS cells were investigated using colony formation, 5-ethynyl-20-deoxyuridine (EDU) staining, and cell cycle/apoptosis assays. The interaction between TA and Src homology 2 phosphatase 2 (SHP-2) was detected by enzyme activity and validated by target-identification methods such as drug affinity responsive target stability (DARTS), cellular thermal shift assay (CETSA), and biolayer interferometry (BLI). The in vivo anti-tumor efficacy of TA was analyzed in the xenograft tumor model. Western blotting analysis was performed to detect the protein expression levels.

Results

TA exhibited antitumor activity against osteosarcoma both in vitro and in vivo by regulating the JAK/STAT3 signaling pathway. Mechanically, TA interacted with SHP-2 directly and activated its phosphatase activity. Importantly, protein tyrosine phosphatase (PTP) inhibitor, SHP-2 inhibitor, and SHP-2 siRNA could reverse the inhibitory effect of TA on the JAK/STAT3 signaling pathway and restored the TA-induced cell death.

Conclusion

TA activated the phosphatase activity of SHP-2, which resulted in the inhibition of the JAK/STAT3 pathway and contributed to the antitumor efficacy of TA. Collectively, these findings suggested that TA could serve as a novel therapeutic agent for the treatment of osteosarcoma.

Anticancer properties of novel zinc oxide quantum dot nanoparticles against breast cancer stem-like cells

Cancer stem cells (CSCs) play an essential role in cancer development, metastasis, relapse, and resistance to treatment. In this article, the effects of three synthesized ZnO nanofluids on proliferation, apoptosis, and stemness markers of breast cancer stem-like cells are reported. The antiproliferative and apoptotic properties of ZnO nanoparticles were evaluated on breast cancer stem-like cell-enriched mammospheres by MTS assay and flowcytometry, respectively. The expression of stemness markers, including WNT1, NOTCH1, β-catenin, CXCR4, SOX2, and ALDH3A1 was assessed by real-time PCR. Western blotting was used to analyze the phosphorylation of Janus kinase 2 (JAK2) and Signal Transducer and Activator of Transcription 3 (STAT3). Markers of stemness were significantly decreased by ZnO nanofluids, especially sample (c) with code ZnO-148 with a different order of addition of polyethylene glycol solution at the end of formulation, which considerably decreased all the markers compared to the controls. All the studied ZnO nanofluids considerably reduced viability and induced apoptosis of spheroidal and parental cells, with ZnO-148 presenting the most effective activity. Using CD95L as a death ligand and ZB4 as an extrinsic apoptotic pathway blocker, it was revealed that none of the nanoparticles induced apoptosis through the extrinsic pathway. Results also showed a marked inhibition of the JAK/STAT pathway by ZnO nanoparticles; confirmed by downregulation of Mcl-1 and Bcl-XL expression. The present data demonstrated that ZnO nanofluids could combat breast CSCs via decreasing stemness markers, stimulating apoptosis, and suppressing JAK/STAT activity.

A novel aryl-guanidinium derivative, VP79s, targets the signal transducer and activator of transcription 3 signaling pathway, downregulates myeloid cell leukaemia-1 and exhibits preclinical activity against multiple myeloma

AIMS

We have recently described a novel guanidinium-based compound, VP79s, which induces cytotoxicity in various cancer cell lines. Here, we aim to investigate the activity of VP79s and associated mechanisms of action in multiple myeloma (MM) cells in vitro and ex vivo.

MAIN METHODS

The effects of VP79s on cell viability and induction of apoptosis was examined in a panel of drug-sensitive and drug-resistant MM cell lines, as well as ex vivo patient samples and normal donor lymphocytes and platelets. Cell signaling pathways associated with the biological effects of VP79s were analysed by immunoblotting and flow cytometry. Gene expression changes were assessed by quantitative real-time PCR analysis.

KEY FINDINGS

VP79s was found to rapidly inhibit both constitutively active and IL-6-induced STAT3 signaling with concurrent downregulation of the IL-6 receptors, CD130 and CD126. VP79s induced a rapid and dose-dependent downregulation of anti-apoptotic Bcl-2 family member, myeloid cell leukaemia-1 (MCL-1). VP79s enhanced bortezomib induced cell death and was also found to overcome bone marrow stromal cell induced drug resistance. VP79s exhibited activity in ex vivo patient samples at concentrations which had no effect on peripheral blood mononuclear cells, lymphocytes and platelets isolated from healthy donors.

SIGNIFICANCE

As VP79s resulted in rapid inhibition of the key IL-6/STAT3 signaling pathway and downregulation of MCL-1 expression with subsequent selective anti-myeloma activity, VP79s may be a potential therapeutic agent with a novel mechanism of action in MM cells.

A novel tin based hydroxamic acid complex induces apoptosis through redox imbalance and targets Stat3/JNK1/MMP axis to overcome drug resistance in cancer

Undesired toxicity and emergence of multidrug resistance (MDR) are the major impediments for the successful application of organotin-based compounds against cancer. Since oxalyl-bis(N-phenyl)hydroxamic acid (OBPHA) exerts significant efficacy against cancer, we believe that derivatives of OBPHA including organotin molecule can show a promising effect against cancer. Herein, we have selected three previously characterized OBPHA derivatives viz., succinyl-bis(N-phenyl)hydroxamic acid (SBPHA), diphenyl-tin succinyl-bis(N-phenyl)hydroxamic acid (Sn-SBPHA), malonyl-bis(N-phenyl)hydroxamic acid (MBPHA) and evaluated their antiproliferative efficacy against both drug resistant (CEM/ADR5000; EAC/Dox) and sensitive (CCRF-CEM; HeLa; EAC/S) cancers. Data revealed that Sn-SBPHA selectively targets drug resistant and sensitive cancers without inducing any significant toxicity to normal cells (Chang Liver). Moreover, shortening of the backbone of SBPHA enhances the efficacy of the newly formed molecule MBPHA by targeting only drug sensitive cancers. Sn-SBPHA induces caspase3-dependent apoptosis through redox-imbalance in both drug resistant and sensitive cancer. Sn-SBPHA also reduced the activation and expression of both MMP2 and MMP9 without altering the expression status of TIMP1 and TIMP2 in drug resistant cancer. In addition, Sn-SBPHA reduced the activation of both STAT3 and JNK1, the transcriptional modulator of MMPs, in a redox-dependent manner in CEM/ADR5000 cells. Thus, Sn-SBPHA targets MMPs by modulating STAT3 and JNK1 in a redox-dependent manner. However, MBPHA and SBPHA fail to target drug resistance and both drug resistant and sensitive cancer respectively. Furthermore, Sn-SBPHA significantly increases the lifespan of doxorubicin resistant and sensitive Ehrlich Ascites Carcinoma bearing mice without inducing any significant systemic-toxicity. Therefore, Sn-SBPHA has the therapeutic potential to target and overcome MDR in cancer.

Aloperine inhibits colorectal cancer cell proliferation and metastasis progress via regulating miR-296-5p/STAT3 axis

Anti-tumorous effect of Aloperine (ALO) has been previously found. This study examined the role and the underlying mechanism of ALO in colorectal cancer (CRC). CRC cells were processed by different concentrations of ALO, and subsequently the cell proliferation was detected by 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and miR-296-5p expression was determined by quantitative real-time polymerase chain reaction (qRT-PCR). Moreover, the target gene of miR-296-5p was predicted by TargetScan and confirmed by dual-luciferase reporter assay. The expressions of signal transducer and activator of transcription 3 (STAT3), apoptosis-related proteins and epithelial-mesenchymal transition (EMT)-related markers were measured by Western blot. Clone formation assay, flow cytometry, wound-healing and Transwell assays were respectively employed to detect cell proliferation, apoptosis, migration and invasion. ALO inhibited CRC cell proliferation in a dose-dependent manner. MiR-296-5p was low-expressed in CRC tissues and cells, and ALO promoted miR-296-5p expression. STAT3 was targeted by miR-296-5p. Up-regulation of miR-296-5p and ALO treatment both suppressed STAT3 expression, inhibited CRC cell proliferation, migration, invasion as well as the expressions of Bcl-2 and N-cadherin, but promoted apoptosis and expressions of Bax and E-cadherin, which were all reversed by overexpressed STAT3. ALO inhibited CRC cell proliferation, metastasis and EMT but promoted apoptosis via regulating miR-296-5p/STAT3 axis.

EMT-cancer cells-derived exosomal miR-27b-3p promotes circulating tumour cells-mediated metastasis by modulating vascular permeability in colorectal cancer

BACKGROUND

Metastasis is the main cause of death in colorectal cancer (CRC). Circulating tumour cells (CTCs) are regarded as the precursor cells of metastasis. The CTCs, which underwent epithelial-mesenchymal transition (EMT), are associated with metastasis and responsible for poor prognosis. EMT cancer cells modulate endothelial permeability in the invasive front and facilitate cancer cell intravasation, resulting in CTCs-mediated distant metastasis. Exosomes derived from cancer cells are key mediators of cancer-host intercommunication. However, the mechanism by which EMT-tumour cells-derived exosomes modulate vascular permeability and promote CTCs generation has remained unclear.

METHODS

Exosomes isolation and purification were conducted by ultra-centrifugation. Exosomal miRNA was identified by sequencing followed by quantitative PCR. In vitro co-culture assay experiments were conducted to evaluate the effect of exosomal miR-27b-3p on the permeability of blood vessel endothelium. Dual-luciferase reporter assay, chromatin immunoprecipitation (ChIP) and RNA immunoprecipitation (RIP) were performed to investigate the underlying mechanism by which miR-27b-3p is packaged into exosomes. A mouse model was established to determine the role of exosomal miR-27b-3p in blood vessel permeability modulation in vivo.

RESULTS

We found that EMT-CRC cells attenuate the blood vessel barrier by transferring miR-27b-3p to human umbilical vein endothelial cells (HUVECs) in exosomes. Mechanically, miR-27b-3p atteuated the expression of vascular endothelial cadherin (VE-Cad) and p120 at the post-transcriptional level by binding to 3'-untranslated region of VE-Cad and p120 directly. The packaging of miR-27b-3p into exosomes was induced by heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), which activated by STAT3. Clinically, miR-27b-3p up-regulated in CRC tissues. Plasma exosomal miR-27b-3p was positively correlated with malignant progression and CTC count in CRC patients. Our study reveals a novel mechanism by which EMT-CRC cells promote metastasis, increasing blood vessel permeability and facilitating the generation of CTCs.

CONCLUSION

Exosomal miR-27b-3p secreted by EMT-CRC cells increases blood vessel permeability and facilitates the generation of CTCs. Exosomal miR-27b-3p may become a promising biomarker for CRC metastasis.

Sanguinarine mediated apoptosis in Non-Small Cell Lung Cancer via generation of reactive oxygen species and suppression of JAK/STAT pathway

Effective treatment of lung cancer remains a significant clinical challenge due to its multidrug resistance and side effects of the current treatment options. The high mortality associated with this malignancy indicates the need for new therapeutic interventions with fewer side effects. Natural compounds offer various benefits such as easy access, minimal side effects, and multi-molecular targets and thus, can prove useful in treating lung cancer. Sanguinarine (SNG), a natural compound, possesses favorable therapeutic potential against a variety of cancers. Here, we examined the underlying molecular mechanisms of SNG in Non-Small Cell Lung Cancer (NSCLC) cells. SNG suppressed cell growth and induced apoptosis via downregulation of the constitutively active JAK/STAT pathway in all the NSCLC cell lines. siRNA silencing of STAT3 in NSCLC cells further confirmed the involvement of the JAK/STAT signaling cascade. SNG treatment increased Bax/Bcl-2 ratio, which contributed to a leaky mitochondrial membrane leading to cytochrome c release accompanied by caspase activation. In addition, we established the antitumor effects of SNG through reactive oxygen species (ROS) production, as inhibiting ROS production prevented the apoptosis-inducing potential of SNG. In vivo xenograft tumor model further validated our in vitro findings. Overall, our study investigated the molecular mechanisms by which SNG induces apoptosis in NSCLC, providing avenues for developing novel natural compound-based cancer therapies.

Swertia chirayita suppresses the growth of non-small cell lung cancer A549 cells and concomitantly induces apoptosis via downregulation of JAK1/STAT3 pathway

Lung carcinoma is the leading cause of cancer-related mortalities worldwide, and present therapeutical interventions are not successful enough to treat this disease in many cases. Recent years have witnessed a surge in exploring natural compounds for their antiproliferative efficacy to expedite the characterization of novel anticancer chemotherapeutics. Swertia chirayita is a valued medicinal herb and possess intrinsic pharmaceutical potential. However, elucidation of its anticancer effects at molecular levels remains unclear and needs to be investigated. We assessed the anticancer and apoptotic efficacy of S. chirayita ethanolic extract (Sw-EtOH) on non-small cell lung cancer (NSCLC) A549 cells during this exploratory study. The results elucidated that S. chirayita extract induced toxic effects within lung cancer cells by ~1 fold during cytotoxicity and LDH release assay at a 400 μg/ml concentration. Sw-EtOH extract elevates the level of ROS, resulting in the disruption of Δψm and release of cytosolic cytochrome c by 3.15 fold. Activation of caspases-3, -8 & -9 also escalated by ~1 fold, which further catalyze the augmentation of PARP cleavage (~3 folds), resulting in a four-fold increase in Sw-EtOH induced apoptosis. The gene expression analysis further demonstrated that Sw-EtOH extracts inhibited JAK1/STAT3 signaling pathway by down-regulating the levels of JAK1 and STAT3 to nearly half a fold. Treatment of Sw-EtOH modulates the expression level of various STAT3 associated proteins, including Bcl-XL, Bcl-2, Mcl-1, Bax, p53, Fas, Fas-L, cyclinD1, c-myc, IL-6, p21 and p27 in NSCLC cells. Thus, our study provided a strong impetus that Sw-EtOH holds the translational potential of being further evaluated as efficient cancer therapeutics and a preventive agent for the management of NSCLC.

Lnc-DC promotes estrogen independent growth and tamoxifen resistance in breast cancer

Selective estrogen receptor modulators (SERMs) such as tamoxifen have proven to be effective in the treatment of estrogen receptor (ER) positive breast cancer. However, a major obstacle for such endocrine therapy is estrogen independent growth, leading to resistance, and the underlying mechanism is not fully understood. The purpose of this study was to determine whether long non-coding RNAs (lncRNAs) are involved in regulation of estrogen independent growth and tamoxifen resistance in ER positive breast cancer. Using a CRISPR/Cas9-based SAM (synergistic activation mediator) library against a focus group of lncRNAs, we identify Lnc-DC as a candidate lncRNA. Further analysis suggests that Lnc-DC is able to reduce tamoxifen-induced apoptosis by upregulation of anti-apoptotic genes such as Bcl2 and Bcl-xL. Furthermore, Lnc-DC activates STAT3 by phosphorylation (pSTAT3^Y705), and the activated STAT3 subsequently induces expression of cytokines which in turn activate STAT3, forming an autocrine loop. Clinically, upregulation of Lnc-DC is associated with poor prognosis. In particular, analysis of a tamoxifen-treated patient cohort indicates that Lnc-DC expression can predict the response to tamoxifen. Together, this study demonstrates a previously uncharacterized function of Lnc-DC/STAT3/cytokine axis in estrogen independent growth and tamoxifen resistance, and Lnc-DC may serve as a potential predictor for tamoxifen response.

G-749 Promotes Receptor Tyrosine Kinase TYRO3 Degradation and Induces Apoptosis in Both Colon Cancer Cell Lines and Xenograft Mouse Models

G-749 is an FLT3 kinase inhibitor that was originally developed as a treatment for acute myeloid leukemia. Some FLT3 kinase inhibitors are dual kinase inhibitors that inhibit the TAM (Tyro3, Axl, Mer) receptor tyrosine kinase family and are used to treat solid cancers such as non-small cell lung cancer (NSCLC) and triple-negative breast cancer (TNBC). AXL promotes metastasis, suppression of immune response, and drug resistance in NSCLC and TNBC. G-749, a potential TAM receptor tyrosine kinase inhibitor, and its derivative SKI-G-801, effectively inhibits the phosphorylation of AXL at nanomolar concentration (IC50 = 20 nM). This study aimed to investigate the anticancer effects of G-749 targeting the TAM receptor tyrosine kinase in colon cancer. Here, we demonstrate the potential of G-749 to effectively inhibit tumorigenesis by degrading TYRO3 via regulated intramembrane proteolysis both in vitro and in vivo. In addition, we demonstrated that G-749 inhibits the signaling pathway associated with cell proliferation in colon cancer cell lines HCT15 and SW620, as well as tumor xenograft mouse models. We propose G-749 as a new therapeutic agent for the treatment of colon cancer caused by abnormal TYRO3 expression or activity.

Recent Developments in Oxazole Derivatives as Anticancer Agents: Review on Synthetic Strategies, Mechanism of Action and SAR studies

BACKGROUND

Cancer is the world's third deadliest disease. Despite the availability of numerous treatments, researchers are focusing on the development of new drugs lacking resistance and toxicity issues. Many newly synthesized drugs fail to reach clinical trials due to poor pharmacokinetic properties. Therefore, there is an imperative requisite to expand novel anticancer agents with in vivo efficacy.

OBJECTIVE

This review emphasizes synthetic methods, contemporary strategies used for the inclusion of oxazole moiety, mechanistic targets along with comprehensive structure-activity relationship studies to provide perspective into the rational design of highly efficient oxazole-based anticancer drugs.

METHODS

Literature related to oxazole derivatives engaged in cancer research is reviewed. This article gives a detailed account of synthetic strategies, targets of oxazole in cancer, including STAT3, Microtubules, G-quadruplex, DNA topoisomerases, DNA damage, Protein kinases, miscellaneous targets, in vitro studies, and some SAR studies.

RESULTS

Oxazole derivatives possess potent anticancer activity by inhibiting novel targets such as STAT3 and G-quadruplex. Oxazoles also inhibit tubulin protein to induce apoptosis in cancer cells. Some other targets such as DNA topoisomerase enzyme, protein kinases, and miscellaneous targets including Cdc25, mitochondrial enzymes, HDAC, LSD1, HPV E2 TAD, NQO1, Aromatase, BCl-6, Estrogen receptor, GRP-78, and Keap-Nrf2 pathway are inhibited by oxazole derivatives Many derivatives showed excellent potencies on various cancer cell lines with IC50 values in nanomolar concentrations.

CONCLUSION

Oxazole is a five-membered heterocycle, with oxygen and nitrogen at 1 and 3 positions respectively. It is often combined with other pharmacophores in the expansion of novel anticancer drugs. In summary, oxazole is a promising entity to develop new anticancer drugs.

Inhibition of STAT3/PD-L1 and Activation of miR193a-5p Are Critically Involved in Apoptotic Effect of Compound K in Prostate Cancer Cells

Since the signal transducer and activator of transcription 3 (STAT3)/programmed death-ligand 1 (PD-L1) signaling plays an important role in tumor-immune microenvironments, in the present study, the role of STAT3/PD-L1 signaling in the apoptotic mechanism of an active ginseng saponin metabolite compound K (CK) was investigated in human prostate cancer cells. Here, CK exerted significant cytotoxicity without hurting RWPE1 normal prostate epithelial cells, increased sub-G1 and cleavage of Poly ADP-ribose polymerase (PARP) and attenuated the expression of pro-PARP and Pro-cysteine aspartyl-specific protease3 (pro-caspase-3) in LANCap, PC-3 and DU145 cells. Further, CK attenuated the expression of p-STAT3 and PD-L1 in DU145 cells along with disrupted the binding of STAT3 to PD-L1. Furthermore, CK effectively abrogated the expression of p-STAT3 and PD-L1 in interferon-gamma (INF-γ)-stimulated DU145cells. Additionally, CK suppressed the expression of vascular endothelial growth factor (VEGF), transforming growth factor-β (TGF-β), interleukin 6 (IL-6) and interleukin 10 (IL-10) as immune escape-related genes in DU145 cells. Likewise, as STAT3 targets genes, the expression of CyclinD1, c-Myc and B-cell lymphoma-extra-large (Bcl-xL) was attenuated in CK-treated DU145 cells. Notably, CK upregulated the expression of microRNA193a-5p (miR193a-5p) in DU145 cells. Consistently, miR193a-5p mimic suppressed p-STAT3, PD-L1 and pro-PARP, while miR193a-5p inhibitor reversed the ability of CK to attenuate the expression of p-STAT3, PD-L1 and pro-PARP in DU145 cells. Taken together, these findings support evidence that CK induces apoptosis via the activation of miR193a-5p and inhibition of PD-L1 and STAT3 signaling in prostate cancer cells.

Delphinidin modulates JAK/STAT3 and MAPKinase signaling to induce apoptosis in HCT116 cells

Delphinidin is an anthocyanin that belongs to the group of flavonoids that exert numerous biological activities. However, the molecular mechanisms underlying the anticancer effects of delphinidin remain poorly understood. In our study we analyzed delphinidin modulate STAT-3 and MAPKinase signaling thereby inhbits cell proliferation and promote apoptosis. Our study demonstrated that delphinidin treatment significantly reduced the viability of human colon cancer HCT116 in a concentration-dependent manner. We noticed that delphinidin effectively induced oxidative stress-mediated apoptosis by generating intracellular ROS, decreasing antioxidant levels, inducing lipid peroxidation, and single-strand break on colon cancer cells. In this study, we observed that delphinidin treatment alters the mitochondrial membrane potential, thereby induces apoptosis was closely associated with the induction of pro-apoptotic Bax, Caspase- 3,8 & 9, cytochrome C, and inhibition of anti-apoptotic protein expression. Studies on STAT-3 and MAPKinase signaling showed delphinidin inhibited the phosphorylation of these transcription factors' activity. Inhibition of STAT-3, p38, and ERK1/2 phosphorylation and modulation pro-apoptotic protein expression might be responsible for the anticancer activity of delphinidin in colon cancer cells.

Advances of Targeted Therapy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the common and fatal malignancies, which is a significant global health problem. The clinical applicability of traditional surgery and other locoregional therapies is limited, and these therapeutic strategies are far from satisfactory in improving the outcomes of advanced HCC. In the past decade, targeted therapy had made a ground-breaking progress in advanced HCC. Those targeted therapies exert antitumor effects through specific signals, including anti-angiogenesis or cell cycle progression. As a standard systemic therapy option, it tremendously improves the survival of this devastating disease. Moreover, the combination of targeted therapy with immune checkpoint inhibitor (ICI) has demonstrated more potent anticancer effects and becomes the hot topic in clinical studies. The combining medications bring about a paradigm shift in the treatment of advanced HCC. In this review, we presented all approved targeted agents for advanced HCC with an emphasis on their clinical efficacy, summarized the advances of multi-target drugs in research for HCC and potential therapeutic targets for drug development. We also discussed the exciting results of the combination between targeted therapy and ICI.

Inflammatory repercussions in female steroid responsive glands after perinatal exposure to bisphenol A and 17-β estradiol

The mammary gland (MG) and female prostate are plastic reproductive organs which are highly responsive to hormones. Thus, endocrine disruptors, such as bisphenol A (BPA) and exogenous estrogens, negatively affect glandular homeostasis. In addition to previously described alterations, changes in inflammatory markers expression also trigger the development of a microenvironment that contributes to tumor progression. The current work aimed to evaluate the inflammatory responses of the MG and prostate gland to BPA (50 µg/kg) and 17-β estradiol (35 µg/kg) exposure during the perinatal window of susceptibility. The results showed that at 6 months of age there was an increase in the number of phospho-STAT3 (P-STAT3) positive cells in the female prostate from animals perinatally exposed to 50 µg/kg BPA daily. In addition, the number of macrophages increased in these animals in comparison with nonexposed animals, as shown by the F4/80 marker. Despite an increase in the incidence of lobuloalveolar and intraductal hyperplasia, the MG did not show any difference in the expression of the four inflammatory markers evaluated: tumor necrosis factor-α, COX-2, P-STAT3, and F4/80. Analysis of both glands from the same animal led to the conclusion that exposure to endocrine disruptors during the perinatal window of susceptibility leads to different inflammatory responses in different reproductive organs. As the prostate is more susceptible to these inflammatory mechanisms, it is reasonable to affirm that possible neoplastic alterations in this organ are related to changes in the inflammatory pattern of the stroma, a characteristic that is not evident in the MG.

Molecular Pathways and Druggable Targets in Head and Neck Squamous Cell Carcinoma

Head and neck cancers are a heterogeneous group of neoplasms, affecting an ever increasing global population. Despite advances in diagnostic technology and surgical approaches to manage these conditions, survival rates have only marginally improved and this has occurred mainly in developed countries. Some improvements in survival, however, have been a result of new management and treatment approaches made possible because of our ever-increasing understanding of the molecular pathways triggered in head and neck oncogenesis, and the growing understanding of the abundant heterogeneity of this group of cancers. Some important pathways are common to other solid tumours, but their impact on reducing the burden of head and neck disease has been less than impressive. Other less known and little-explored pathways may hold the key to the development of potential druggable targets. The extensive work carried out over the last decade, mostly utilising next generation sequencing has opened up the development of many novel approaches to head and neck cancer treatment. This paper explores our current understanding of the molecular pathways of this group of tumours and outlines associated druggable targets which are deployed as therapeutic approaches in head and neck oncology with the ultimate aim of improving patient outcomes and controlling the personal and economic burden of head and neck cancer.

Epigenetic roles of PIWI proteins and piRNAs in colorectal cancer

Small non‐coding RNAs (sncRNAs) are a subgroup of non‐coding RNAs, with less than 200 nucleotides length and no potential for coding proteins. PiRNAs, a member of sncRNAs, were first discovered more than a decade ago and have attracted researcher’s attention because of their gene regulatory function both in the nucleus and in the cytoplasm. Recent investigations have found that the abnormal expression of these sncRNAs is involved in many human diseases, including cancers. Colorectal cancer (CRC), as a common gastrointestinal malignancy, is one of the important causes of cancer‐related deaths through the entire world and appears to be a consequence of mutation in the genome and epigenetic alterations. The aim of this review is to realize whether there is a relationship between CRC and piRNAs or not.

Combined inhibition of STAT and Notch signalling effectively suppresses tumourigenesis by inducing apoptosis and inhibiting proliferation, migration and invasion in glioblastoma cells

Glioblastoma multiforme (GBM) is the most aggressive primary brain cancer and this is due to cancer cells being apoptosis-resistant and having increased cell proliferation, migration, invasion, and angiogenesis properties. Previous studies have indicated both STAT and Notch pathways being important for initiation and progression in GBM. In this work, we first studied the effects of STAT inhibitors on Notch signalling using small molecule STAT inhibitors. It was observed that STAT inhibitors surprisingly activated Notch signalling by inducing NICD and Notch target genes in GBM cells. Thus, we aimed to combine STAT inhibitor treatment with a Notch pathway inhibitor and study effects on GBM tumourigenesis. STAT5 inhibitor (Pimozide) and STAT3 inhibitor (S3I-201) were individually used in combination with γ-secretase inhibitor (DAPT), an inhibitor of Notch signalling, in a panel of GBM cells for cell proliferation and epithelial plasticity changes. Compared with single-agent treatments, combinatorial treatments with the STAT and Notch inhibitors significantly increased apoptosis in the treated cells, impairing cell proliferation, migration, and invasion. These findings suggest that concurrent blocking of STAT and Notch signalling pathways could provide added therapeutic benefit for the treatment of glioblastoma.

The targetable nanoparticle BAF312@cRGD-CaP-NP represses tumor growth and angiogenesis by downregulating the S1PR1/P-STAT3/VEGFA axis in triple-negative breast cancer

Background

Overexpressed vascular endothelial growth factor A (VEGFA) and phosphorylated signal transducer and activator of transcription 3 (P-STAT3) cause unrestricted tumor growth and angiogenesis of breast cancer (BRCA), especially triple-negative breast cancer (TNBC). Hence, novel treatment strategy is urgently needed.

Results

We found sphingosine 1 phosphate receptor 1 (S1PR1) can regulate P-STAT3/VEGFA. Database showed S1PR1 is highly expressed in BRCA and causes the poor prognosis of patients. Interrupting the expression of S1PR1 could inhibit the growth of human breast cancer cells (MCF-7 and MDA-MB-231) and suppress the angiogenesis of human umbilical vein endothelial cells (HUVECs) via affecting S1PR1/P-STAT3/VEGFA axis. Siponimod (BAF312) is a selective antagonist of S1PR1, which inhibits tumor growth and angiogenesis in vitro by downregulating the S1PR1/P-STAT3/VEGFA axis. We prepared pH-sensitive and tumor-targeted shell-core structure nanoparticles, in which hydrophilic PEG2000 modified with the cyclic Arg-Gly-Asp (cRGD) formed the shell, hydrophobic DSPE formed the core, and CaP (calcium and phosphate ions) was adsorbed onto the shell; the nanoparticles were used to deliver BAF312 (BAF312@cRGD-CaP-NPs). The size and potential of the nanoparticles were 109.9 ± 1.002 nm and − 10.6 ± 0.056 mV. The incorporation efficacy for BAF312 was 81.4%. Results confirmed BAF312@cRGD-CaP-NP could dramatically inhibit tumor growth and angiogenesis in vitro and in MDA-MB-231 tumor-bearing mice via downregulating the S1PR1/P-STAT3/VEGFA axis.

Conclusions

Our data suggest a potent role for BAF312@cRGD-CaP-NPs in treating BRCA, especially TNBC by downregulating the S1PR1/P-STAT3/VEGFA axis.

Graphic abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-021-00904-6.

Structure-based discovery of potent and selective small-molecule inhibitors targeting signal transducer and activator of transcription 3 (STAT3)

STAT3 has been validated as an attractive anticancer target due to its important roles in cancer initiation and progression. However, discovery of potent and selective STAT3 small-molecule inhibitors with druglike properties is still challenging. In this study, two series of substituted 2-phenylquinolines and 2-arylimidazo[1,2-a]pyridines were designed through structure-based drug discovery approach by condensing the privileged structures of STX-119 and SH4-54. Our study has resulted in the discovery of a number of highly potent and selective STAT3 inhibitors, exemplified by compound 39 with the privileged structure of 2-phenylimidazo[1,2-a]pyridine, which selectively inhibits phosphorylation of STAT3 and suppresses subsequent signaling pathway. Moreover, 39 inhibits cell growth, migration and invasion of human triple negative breast cancer (TNBC) cells lines. Consistently, it achieves significant and dose-dependent tumor growth inhibition in both cell line-derived and patient-derived xenograft tumor models in mice. These results clearly indicate that 39 is a highly potent and selective STAT3 inhibitor.

Bone marrow cells are differentiated into MDSCs by BCC-Ex through down-regulating the expression of CXCR4 and activating STAT3 signalling pathway

Studies showed that the increase of myeloid‐derived suppressor cells (MDSCs) in tumour microenvironment is closely related to the resistant treatment and poor prognosis of metastatic breast cancer. However, the effect of tumour‐derived exosomes on MDSCs and its mechanism are not clear. Here, we reported that breast cancer cells (4T1)‐secreted exosomes (BCC‐Ex) were able to differentiate bone marrow cells into MDSCs and significantly inhibited the proliferation of T lymphocytes to provide an immunosuppressive microenvironment for cancer cells in vivo and in vitro. The number of MDSCs in bone marrow and spleen of 4T1 tumour‐bearing mice and BCC‐Ex infused mice was significantly higher than that of normal mice, whereas the number of T lymphocytes in spleen was significantly decreased. In addition, BCC‐Ex markedly promoted the differentiation of MDSCs from bone marrow cells or bone marrow cells derived macrophages, seen as the increased expressions of MDSCs‐related functional proteins Arginase‐1 (Arg‐1) and inducible nitric oxide synthase (iNOS). Furthermore, BCC‐Ex significantly down‐regulated the expressions of chemokine receptor CXCR4 and markedly up‐regulated the levels of inflammatory cytokines IL‐6 and IL‐10 in bone marrow cells and macrophages and remarkably inhibited the division and proliferation of T cells. Importantly, CXCR4 agonist, CXCL12, could reverse the function of BCC‐Ex, indicating that BCC‐Ex‐induced MDSCs might be dependent on the down‐regulation of CXCR4. Western blot showed that BCC‐Ex significantly promoted the phosphorylation of STAT3 in bone marrow cells, resulting in the inhibitions of the proliferation and apoptosis of bone marrow cells, and the aggravation of the differentiation of bone marrow cells into MDSCs.

Study on the Mechanism of Lianpu Drink for the Treatment of Chronic Gastritis Based on Network Pharmacology

Chronic gastritis (CG) places a considerable burden on the healthcare system worldwide. Traditional Chinese Medicine (TCM) formulas characterized by multicompounds and multitargets have been acknowledged with striking effects in the treatment of CG in China's history. Nevertheless, their accurate mechanisms of action are still ambiguous. In this study, we analyzed the effective compounds, potential targets, and related biological pathway of Lianpu Drink (LPD), a TCM formula which has been reported to have a therapeutic effect on CG, by contrasting a “compound-target-disease” network. According to the results, 92 compounds and 5762 putative targets of LPD were screened; among them, 8 compounds derived from different herbs in LPD and 30 common targets related to LPD and CG were selected as candidate compounds and precision targets, respectively. Meanwhile, the predicted common targets were verified by Kyoto Encyclopedia of Genes and Genomes (KEGG) signaling pathway analysis and pharmacological experiments. The results demonstrated that quercetin, ephedrine, trigonelline, crocetin, and β-sitosterol were major effective compounds of LPD responsible for the CG treatment by inhibiting the activation of the JAK 2-STAT 3 signaling pathway to reduce the expressions of cyclin D1 and Bcl-2 proteins. The study provides evidence for the mechanism of understanding of LPD for the treatment of CG.

Antitumor Activity of Pulvomycin via Targeting Activated-STAT3 Signaling in Docetaxel-Resistant Triple-Negative Breast Cancer Cells

Although docetaxel-based regimens are common and effective for early-stage triple-negative breast cancer (TNBC) treatment, acquired drug resistance frequently occurs. Therefore, a novel therapeutic strategy for docetaxel-resistant TNBC is urgently required. Signal transducer and activator of transcription 3 (STAT3) plays a pivotal role in the tumorigenesis and metastasis of numerous cancers, and STAT3 signaling is aberrantly activated in TNBC cells. In this study, a docetaxel-resistant TNBC cell line (MDA-MB-231-DTR) was established, and mechanisms for the antitumor activity of pulvomycin, a novel STAT3 inhibitor isolated from marine-derived actinomycete, were investigated. Levels of activated STAT3 (p-STAT3 (Y705)) increased in docetaxel-resistant cells, and knockdown of STAT3 recovered the sensitivity to docetaxel in MDA-MB-231-DTR cells. Pulvomycin effectively inhibited the proliferation of both cell lines. In addition, pulvomycin suppressed the activation of STAT3 and subsequently induced G0/G1 cell cycle arrest and apoptosis. Pulvomycin also significantly inhibited the invasion and migration of MDA-MB-231-DTR cells through the modulation of epithelial-mesenchymal transition markers. In an MDA-MB-231-DTR-bearing xenograft mouse model, the combination of pulvomycin and docetaxel effectively inhibited tumor growth through STAT3 regulation. Thus, our findings demonstrate that the combination of docetaxel and STAT3 inhibitors is an effective strategy for overcoming docetaxel resistance in TNBC.

A 2-Benzylmalonate Derivative as STAT3 Inhibitor Suppresses Tumor Growth in Hepatocellular Carcinoma by Upregulating β-TrCP E3 Ubiquitin Ligase

The aberrant activation of a signal transducer and activator of transcription 3 (STAT3) restrains type I interferon (IFN) α/β-induced antiviral responses and is associated with the development of cancer. Designing specific STAT3 inhibitors will thus provide new options for use as IFN therapy. Herein, we identified a novel small molecule, dimethyl 2-(4-(2-(methyl(phenyl(p-tolyl)methyl)amino)ethoxy)benzyl)malonate (CIB-6), which can inhibit the IFN-α-induced interferon stimulated response element (ISRE) luciferase reporter (IC₅₀ value = 6.4 μM) and potentiate the antiproliferative effect of IFN-α in human hepatocellular carcinoma (HCC) cells. CIB-6 was found to bind to the STAT3 Src homology 2 (SH2) domain, thereby selectively inhibiting STAT3 phosphorylation without affecting Janus kinases and STAT1/2. CIB-6 also inhibited the migration and invasion of HCC cells by inhibiting the epithelial-mesenchymal transition (EMT) process. Mechanistically, CIB-6 reduced the expression of β-catenin (an EMT key protein) via upregulating β-transducin repeat-containing protein (β-TrCP) and curbed nuclear factor kappa-B (NF-κB) activation through restricting the phosphorylation of the inhibitor of NF-κB (IκB) kinase (IKK) via STAT3 inhibition. Treatment with CIB-6 significantly retarded tumor growth in nude mice with SK-HEP-1 xenografts. In addition, clinical sample analysis revealed that lower β-TrCP and higher β-catenin expression could affect the median survival time of HCC patients. Our findings suggest that CIB-6 could be a new therapeutic strategy for HCC therapy through STAT3-mediated β-TrCP/β-catenin/NF-κB axis.

Noncoding RNAs Associated with Therapeutic Resistance in Pancreatic Cancer

Therapeutic resistance is an inevitable impediment towards effective cancer therapies. Evidence accumulated has shown that the signaling pathways and related factors are fundamentally responsible for therapeutic resistance via regulating diverse cellular events, such as epithelial-to-mesenchymal transition (EMT), stemness, cell survival/apoptosis, autophagy, etcetera. Noncoding RNAs (ncRNAs) have been identified as essential cellular components in gene regulation. The expression of ncRNAs is altered in cancer, and dysregulated ncRNAs participate in gene regulatory networks in pathological contexts. An in-depth understanding of molecular mechanisms underlying the modulation of therapeutic resistance is required to refine therapeutic benefits. This review presents an overview of the recent evidence concerning the role of human ncRNAs in therapeutic resistance, together with the feasibility of ncRNAs as therapeutic targets in pancreatic cancer.

High dose acetaminophen inhibits STAT3 and has free radical independent anti-cancer stem cell activity

High-dose acetaminophen (AAP) with delayed rescue using n-acetylcysteine (NAC), the FDA-approved antidote to AAP overdose, has demonstrated promising antitumor efficacy in early phase clinical trials. However, the mechanism of action (MOA) of AAP's anticancer effects remains elusive. Using clinically relevant AAP concentrations, we evaluated cancer stem cell (CSC) phenotype in vitro and in vivo in lung cancer and melanoma cells with diverse driver mutations. Associated mechanisms were also studied. Our results demonstrated that AAP inhibited 3D spheroid formation, self-renewal, and expression of CSC markers when human cancer cells were grown in serum-free CSC media. Similarly, anti-CSC activity was demonstrated in vivo in xenograft models - tumor formation following in vitro treatment and ex-vivo spheroid formation following in vivo treatment. Intriguingly, NAC, used to mitigate AAP's liver toxicity, did not rescue cells from AAP's anti-CSC effects, and AAP failed to reduce glutathione levels in tumor xenograft in contrast to mice liver tissue suggesting nonglutathione-related MOA. In fact, AAP mediates its anti-CSC effect via inhibition of STAT3. AAP directly binds to STAT3 with an affinity in the low micromolar range and a high degree of specificity for STAT3 relative to STAT1. These findings have high immediate translational significance concerning advancing AAP with NAC rescue to selectively rescue hepatotoxicity while inhibiting CSCs. The novel mechanism of selective STAT3 inhibition has implications for developing rational anticancer combinations and better patient selection (predictive biomarkers) for clinical studies and developing novel selective STAT3 inhibitors using AAP's molecular scaffold.

Computational Analysis of Drug Resistance Network in Lung Adenocarcinoma

BACKGROUND

Lung cancer is a significant health problem and accounts for one-third of the deaths worldwide. A great majority of these deaths are caused by non-small cell lung cancer (NSCLC). Chemotherapy is the leading treatment method for NSCLC, but resistance to chemotherapeutics is an important limiting factor that reduces the treatment success of patients with NSCLC.

OBJECTIVE

In this study, the relationship between differentially expressed genes affecting the survival of the patients, according to the bioinformatics analyses, and the mechanism of drug resistance is investigated for non-small cell lung adenocarcinoma patients.

METHODS

Five hundred thirteen patient samples were compared with fifty-nine control samples. The employed dataset was downloaded from The Cancer Genome Atlas (TCGA) database. The information on how the drug activity altered against the expressional diversification of the genes was extracted from the NCI-60 database. Four hundred thirty-three drugs with known mechanism of action (MoA) were analyzed. Diversifications of the activity of these drugs related to genes were considered based on nine lung cancer cell lines virtually. The analyses were performed using R programming language, GDCRNATools, rcellminer, and Cytoscape.

RESULTS

This work analyzed the common signaling pathways and expressional alterations of the proteins in these pathways associated with survival and drug resistance in lung adenocarcinoma. Deduced computational data demonstrated that proteins of EGFR, JNK/MAPK, NF-κB, PI3K /AKT/mTOR, JAK/STAT, and Wnt signaling pathways were associated with molecular mechanism of resistance to anticancer drugs in NSCLC cells.

CONCLUSION

To understand the relationships between resistance to anticancer drugs and EGFR, JNK/MAPK, NF-κB, PI3K /AKT/mTOR, JAK/STAT, and Wnt signaling pathways is an important approach to design effective therapeutics for individuals with NSCLC adenocarcinoma.

A C-terminal fragment of adhesion protein fibulin-7 inhibits growth of murine breast tumor by regulating macrophage reprogramming

Recent reports have shown that a C-terminal fragment of adhesion protein Fibulin7 (Fbln7-C) could demonstrate both antiangiogenic and anti-inflammatory activities. The current study investigated the potential of Fbln7-C as a modulator of tumor-associated macrophages (TAMs) and its potential as an anticancer therapeutic. Our in vitro data show that Fbln7-C could inhibit the tumor cell line (MDA-MB-231) supernatant-induced reprogramming of human monocytes into immunosuppressive TAMs as indicated by higher expression of pERK1/2 and pSTAT1 molecules, and reduced expression of CD206 protein and arg1, ido, and vegf transcripts in monocytes cultured in the presence of Fbln7-C compared to controls. Interestingly, Fbln7-C-treated macrophages retained their altered phenotype even after the removal of Fbln7-C, and their secretome demonstrated anticancer activities. Finally, in a 4T1-induced murine breast tumor model, intravenous administration of Fbln7-C, following the appearance of measurable tumors, significantly reduced the growth and weight of the tumors. Detailed phenotypic analysis of the infiltrated monocyte/macrophage populations (F480+ Ly6G- CD11b+ ) at day 23 postinduction showed a higher percentage of inflammatory monocytes (F480+ Ly6Chi CD11b+ ) and a delayed differentiation into anti-inflammatory TAMs as evident by their reduced levels of CD206 expression. In conclusion, the above data suggest that Fbln7-C could regulate the tumor environment-induced macrophage reprogramming and has the potential for cancer therapeutics.

Inhibition of microRNA-17 enhances cisplatin-induced apoptosis of human tongue squamous carcinoma cell

MicroRNA-17 (miR-17) was reported to promote cell proliferation and migration of various types of cancers. However, the mechanism remains unclear. This present study was designed to explore the potential mechanism. Downregulation of miR-17 in CAL-27 cells was performed by transfecting anti-miR-27 plasmids. Xenograft tumor model was carried out to detect the effect of inhibition of microRNA-17 on tongue squamous carcinoma growth. MiR-17 inhibition promotes cisplatin-induced apoptosis via regulating the expression of apoptotic molecules. MiR-17 inhibition promotes cisplatin-induced autophagy of CAL-27 cells. Mechanically, miR-17 inhibition promotes apoptosis and autophagy through STAT3 signaling pathway. Xenograft tumor model showed that miR-17 inhibition attenuates tongue squamous carcinoma growth and promotes tongue squamous carcinoma cell apoptosis in vivo. MiR-17 inhibition enhances cisplatin-induced apoptosis of human tongue squamous carcinoma cell. Our study supplies the evidence that miR-17 may serve as the potential target for human tongue squamous carcinoma treatment.

Catechol enhances chemo‑ and radio‑sensitivity by targeting AMPK/Hippo signaling in pancreatic cancer cells

Overcoming chemo‑ and radio‑resistance is a major challenge in pancreatic cancer treatment. Therefore, there is an urgent need to discover novel therapeutic approaches to avoid chemo‑ and radio‑resistance in pancreatic cancer. Catechol is a phytochemical found in some fruits and vegetables. A few studies have reported on the potential anticancer effects of pure catechol. The present study aimed to explore the chemo‑ and radio‑sensitizing effects of catechol in Panc‑1 human pancreatic cancer cells. The effects of catechol on Panc‑1 cell proliferation, clonogenic survival, invasion, and migration were assessed using MTT, cell migration, and Transwell invasion assays. The chemo‑ and radio‑sensitizing effects of catechol on Panc‑1 cells were evaluated via MTT assay and flow cytometry. Western blotting was conducted to analyze the expression of proteins involved in several mechanisms induced by catechol in Panc‑1 cells, including growth inhibition, apoptosis, suppression of epithelial‑mesenchymal transition (EMT), and chemo‑ and radio‑sensitizing activities. The results indicated that catechol inhibited proliferation, promoted apoptosis, and suppressed cell migration, invasion, and EMT in Panc‑1 cells in a dose‑dependent manner. Catechol treatment also induced the phosphorylation of AMP‑activated protein kinase (AMPK) with a concomitant reduction in the expression of Hippo signaling pathway components, including Yes‑associated protein, cysteine‑rich angiogenic inducer 61, and connective tissue growth factor. In addition, catechol enhanced the chemosensitivity of Panc‑1 cells to gemcitabine, a commonly used chemotherapy in pancreatic cancer treatment. A combination of catechol and radiation enhanced apoptosis and increased the expression of two radiation‑induced DNA damage markers, p‑ATM and p‑Chk2. Collectively, the present results demonstrated that catechol, a naturally occurring compound, could suppress the proliferation of pancreatic cancer cells, reduce the expression of EMT‑related proteins, and enhance the chemo‑ and radio‑sensitivity of Panc‑1 cells by targeting AMPK/Hippo signaling.