Strategies and Approaches of Targeting STAT3 for Cancer Treatment

Inhibition of STAT3: A promising approach to enhancing the efficacy of chemotherapy in medulloblastoma

Medulloblastoma is a type of brain cancer that primarily affects children. While chemotherapy has been shown to be effective in treating medulloblastoma, the development of chemotherapy resistance remains a challenge. One potential therapeutic approach is to selectively inhibit the inducible transcription factor called STAT3, which is known to play a crucial role in the survival and growth of tumor cells. The activation of STAT3 has been linked to the growth and progression of various cancers, including medulloblastoma. Inhibition of STAT3 has been shown to sensitize medulloblastoma cells to chemotherapy, leading to improved treatment outcomes. Different approaches to STAT3 inhibition have been developed, including small-molecule inhibitors and RNA interference. Preclinical studies have shown the efficacy of STAT3 inhibitors in medulloblastoma, and clinical trials are currently ongoing to evaluate their safety and effectiveness in patients with various solid tumors, including medulloblastoma. In addition, researchers are also exploring ways to optimize the use of STAT3 inhibitors in combination with chemotherapy and identify biomarkers that can predict treatment that will help to develop personalized treatment strategies. This review highlights the potential of selective inhibition of STAT3 as a novel approach for the treatment of medulloblastoma and suggests that further research into the development of STAT3 inhibitors could lead to improved outcomes for patients with aggressive cancer.

Unveiling the potential of isatin-grafted phenyl-1,2,3-triazole derivatives as dual VEGFR-2/STAT-3 inhibitors: Design, synthesis and biological assessments

The use of VEGFR-2 inhibitors as a stand-alone treatment has proven to be ineffective in clinical trials due to the robustness of cellular response loops that lead to treatment resistance when only targeting VEGFR-2. The over-activation of the signal transducer/activator of transcription 3 (STAT-3) is expected to significantly impact treatment failure and resistance to VEGFR-2 inhibitors. In this study, we propose the concept of combined inhibition of VEGFR-2 and STAT-3 to combat induced STAT-3-mediated resistance to VEGFR-2 inhibition therapy. To explore this, we synthesized new isatin-grafted phenyl-1,2,3-triazole derivatives "6a-n" and "9a-f". Screening on PANC1 and PC3 cancer cell lines revealed that compounds 6b, 6 k, 9c, and 9f exhibited sub-micromolar ranges. The most promising molecules, 6b, 6 k, 9c, and 9f, demonstrated the highest inhibition when tested as dual inhibitors on VEGFR-2 (with IC50 range 53-82 nM, respectively) and STAT-3 (with IC50 range 5.63-10.25 nM). In particular, triazole 9f showed the best results towards both targets. Inspired by these findings, we investigated whether 9f has the ability to trigger apoptosis in prostate cancer PC3 cells via the assessment of the expression levels of the apoptotic markers Caspase-8, Bcl-2, Bax, and Caspase-9. Treatment of the PC3 cells with compound 9f significantly inhibited the protein expression levels of VEGFR-2 and STAT-3 kinases compared to the control.

Synthesis and evaluation of [18F]FBNAF, a STAT3-targeting probe, for PET imaging of tumor microenvironment

BACKGROUND

Signal transducer and activator of transcription 3 (STAT3) is a protein that regulates cell proliferation and differentiation, and it is attracting attention as a new index for evaluating cancer pathophysiology, as its activation has been highly correlated with the development and growth of tumors. With the development of STAT3 inhibitors, the demand for imaging probes will intensify. Noninvasive STAT3 imaging can help determine the cancer status and predict the efficacy of STAT3 inhibitors. In this study, we aimed to develop an imaging probe targeting STAT3 and synthesized [18F]FBNAF, which was derived from a STAT3-selective inhibitor as the lead compound, followed by in vitro and in vivo evaluations of [18F]FBNAF in positron emission tomography for STAT3.

RESULTS

The results revealed that FBNAF concentration-dependently inhibited STAT3 phosphorylation, similar to the lead compound, thereby supporting radiosynthesis. [18F]FBNAF was easily synthesized from the pinacol boronate ester precursor with suitable radiochemical conversion (46%), radiochemical yield (6.0%), and radiochemical purity (> 97%). [18F]FBNAF exhibited high stability in vitro and in vivo, and radioactivity accumulated in tumor tissues expressing STAT3 with an increasing tumor/blood ratio over time, peaking at 2.6 ± 0.8 at 120 min after injection in tumor-bearing mice. Tumor radioactivity was significantly reduced by the coinjection of a STAT3-selective inhibitor. Furthermore, the localization of radioactivity was almost consistent with STAT3 expression based on ex vivo autoradiography and immunohistochemistry using adjacent tumor sections.

CONCLUSIONS

Thus, [18F]FBNAF could be the first promising STAT3-targeting probe for PET imaging. A STAT3 imaging probe provides meaningful information on STAT3-associated cancer conditions and in tumor microenvironment.

Alantolactone enhances the sensitivity of melanoma to MAPK pathway inhibitors by targeting inhibition of STAT3 activation and down-regulating stem cell markers

Mitogen-activated protein kinase inhibitors (MAPKi) were the first line drugs for advanced melanoma patients with BRAF mutation. Targeted therapies have significant therapeutic effects; however, drug resistance hinders their long-term efficacy. Therefore, the development of new therapeutic strategies against MAPKi resistance is critical. Our previous results showed that MAPKi promote feedback activation of STAT3 signaling in BRAF-mutated cancer cells. Studies have shown that alantolactone inhibited the activation of STAT3 in a variety of tumor cells. Our results confirmed that alantolactone suppressed cell proliferation and promoted apoptosis by inhibiting STAT3 feedback activation induced by MAPKi and downregulating the expression of downstream Oct4 and Sox2. The inhibitory effect of alantolactone combined with a MAPKi on melanoma cells was significantly stronger than that on normal cells. In vivo and in vitro experiments showed that combination treatment was effective against drug-resistant melanomas. Our research indicates a potential novel combination therapy (alantolactone and MAPKi) for patients with BRAF-mutated melanoma.

The importance of integrated therapies on cancer: Silibinin, an old and new molecule

In the landscape of cancer treatments, the efficacy of coadjuvant molecules remains a focus of attention for clinical research with the aim of reducing toxicity and achieving better outcomes. Most of the pathogenetic processes causing tumour development, neoplastic progression, ageing, and increased toxicity involve inflammation. Inflammatory mechanisms can progress through a variety of molecular patterns. As is well known, the ageing process is determined by pathological pathways very similar and often parallel to those that cause cancer development. Among these complex mechanisms, inflammation is currently much studied and is often referred to in the geriatric field as 'inflammaging'. In this context, treatments active in the management of inflammatory mechanisms could play a role as adjuvants to standard therapies. Among these emerging molecules, Silibinin has demonstrated its anti-inflammatory properties in different neoplastic types, also in combination with chemotherapeutic agents. Moreover, this molecule could represent a breakthrough in the management of age-related processes. Thus, Silibinin could be a valuable adjuvant to reduce drug-related toxicity and increase therapeutic potential. For this reason, the main aim of this review is to collect and analyse data presented in the literature on the use of Silibinin, to better understand the mechanisms of the functioning of this molecule and its possible therapeutic role.

Impact of STAT-signaling pathway on cancer-associated fibroblasts in colorectal cancer and its role in immunosuppression

Colorectal cancer (CRC) remains one of the most commonly diagnosed and deadliest types of cancer worldwide. CRC displays a desmoplastic reaction (DR) that has been inversely associated with poor prognosis; less DR is associated with a better prognosis. This reaction generates excessive connective tissue, in which cancer-associated fibroblasts (CAFs) are critical cells that form a part of the tumor microenvironment. CAFs are directly involved in tumorigenesis through different mechanisms. However, their role in immunosuppression in CRC is not well understood, and the precise role of signal transducers and activators of transcription (STATs) in mediating CAF activity in CRC remains unclear. Among the myriad chemical and biological factors that affect CAFs, different cytokines mediate their function by activating STAT signaling pathways. Thus, the harmful effects of CAFs in favoring tumor growth and invasion may be modulated using STAT inhibitors. Here, we analyze the impact of different STATs on CAF activity and their immunoregulatory role.

Piperlongumine: the amazing amide alkaloid from Piper in the treatment of breast cancer

Piperlongumine (PL), an alkaloid found primarily in the fruits and roots of the plant Piper longum L. (Piperaceae), is a natural compound that exhibits potent activity against various cancer cell proliferation. The most frequently caused malignancy in women globally, breast cancer (BC), has been demonstrated to be significantly inhibited by PL. Apoptosis, cell cycle arrest, increased ROS generation, and changes in the signalling protein's expression are all caused by the numerous signalling pathways that PL impacts. Since BC cells resist conventional chemotherapeutic drugs (doxorubicin, docetaxel etc.), researchers have shown that the drugs in combination with PL can exhibit a synergistic effect, greater than the effects of the drug or PL alone. Recently, techniques for drug packaging based on nanotechnology have been employed to improve PL release. The review has presented an outline of the chemistry of PL, its molecular basis in BC, its bioavailability, toxicity, and nanotechnological applications. An attempt to understand the future prospects and direction of research about the compound has also been discussed.

Triptolide, a Cancer Cell Proliferation Inhibitor, Causes Zebrafish Muscle Defects by Regulating Notch and STAT3 Signaling Pathways

Triptolide is a natural compound in herbal remedies with anti-inflammatory and anti-proliferative properties. We studied its effects on critical signaling processes within the cell, including Notch1 and STAT3 signaling. Our research showed that triptolide reduces cancer cell proliferation by decreasing the expression of downstream targets of these signals. The levels of each signal-related protein and mRNA were analyzed using Western blot and qPCR methods. Interestingly, inhibiting one signal with a single inhibitor alone did not significantly reduce cancer cell proliferation. Instead, MTT assays showed that the simultaneous inhibition of Notch1 and STAT3 signaling reduced cell proliferation. The effect of triptolide was similar to a combination treatment with inhibitors for both signals. When we conducted a study on the impact of triptolide on zebrafish larvae, we found that it inhibited muscle development and interfered with muscle cell proliferation, as evidenced by differences in the staining of myosin heavy chain and F-actin proteins in confocal fluorescence microscopy. Additionally, we noticed that inhibiting a single type of signaling did not lead to any significant muscle defects. This implies that triptolide obstructs multiple signals simultaneously, including Notch1 and STAT3, during muscle development. Chemotherapy is commonly used to treat cancer, but it may cause muscle loss due to drug-related adverse reactions or other complex mechanisms. Our study suggests that anticancer agents like triptolide, inhibiting essential signaling pathways including Notch1 and STAT3 signaling, may cause muscle atrophy through anti-proliferative activity.

Stat3 Regulates Developmental Hematopoiesis and Impacts Myeloid Cell Function via Canonical and Non-Canonical Modalities

INTRODUCTION

Signal transducer and activator of transcription (STAT) 3 is extensively involved in the development, homeostasis, and function of immune cells, with STAT3 disruption associated with human immune-related disorders. The roles ascribed to STAT3 have been assumed to be due to its canonical mode of action as an inducible transcription factor downstream of multiple cytokines, although alternative noncanonical functional modalities have also been identified. The relative involvement of each mode was further explored in relevant zebrafish models.

METHODS

Genome editing with CRISPR/Cas9 was used to generate mutants of the conserved zebrafish Stat3 protein: a loss of function knockout (KO) mutant and a mutant lacking C-terminal sequences including the transactivation domain (ΔTAD). Lines harboring these mutations were analyzed with respect to blood and immune cell development and function in comparison to wild-type zebrafish.

RESULTS

The Stat3 KO mutant showed perturbation of hematopoietic lineages throughout primitive and early definitive hematopoiesis. Neutrophil numbers did not increase in response to lipopolysaccharide (LPS) or granulocyte colony-stimulating factor (G-CSF) and their migration was significantly diminished, the latter correlating with abrogation of the Cxcl8b/Cxcr2 pathway, with macrophage responses perturbed. Intriguingly, many of these phenotypes were not shared by the Stat3 ΔTAD mutant. Indeed, only neutrophil and macrophage development were disrupted in these mutants with responsiveness to LPS and G-CSF maintained, and neutrophil migration actually increased.

CONCLUSION

This study has identified roles for zebrafish Stat3 within hematopoietic stem cells impacting multiple lineages throughout primitive and early definitive hematopoiesis, myeloid cell responses to G-CSF and LPS and neutrophil migration. Many of these roles showed conservation, but notably several involved noncanonical modalities, providing additional insights for relevant diseases.

Signaling by Type I Interferons in Immune Cells: Disease Consequences

This review addresses interferon (IFN) signaling in immune cells and the tumor microenvironment (TME) and examines how this affects cancer progression. The data reveal that IFNs exert dual roles in cancers, dependent on the TME, exhibiting both anti-tumor activity and promoting cancer progression. We discuss the abnormal IFN signaling induced by cancerous cells that alters immune responses to permit their survival and proliferation.

Latent Epstein-Barr virus infection collaborates with Myc over-expression in normal human B cells to induce Burkitt-like Lymphomas in mice

Epstein-Barr virus (EBV) is an important cause of human lymphomas, including Burkitt lymphoma (BL). EBV+ BLs are driven by Myc translocation and have stringent forms of viral latency that do not express either of the two major EBV oncoproteins, EBNA2 (which mimics Notch signaling) and LMP1 (which activates NF-κB signaling). Suppression of Myc-induced apoptosis, often through mutation of the TP53 (p53) gene or inhibition of pro-apoptotic BCL2L11 (BIM) gene expression, is required for development of Myc-driven BLs. EBV+ BLs contain fewer cellular mutations in apoptotic pathways compared to EBV-negative BLs, suggesting that latent EBV infection inhibits Myc-induced apoptosis. Here we use an EBNA2-deleted EBV virus (ΔEBNA2 EBV) to create the first in vivo model for EBV+ BL-like lymphomas derived from primary human B cells. We show that cord blood B cells infected with both ΔEBNA2 EBV and a Myc-expressing vector proliferate indefinitely on a CD40L/IL21 expressing feeder layer in vitro and cause rapid onset EBV+ BL-like tumors in NSG mice. These LMP1/EBNA2-negative Myc-driven lymphomas have wild type p53 and very low BIM, and express numerous germinal center B cell proteins (including TCF3, BACH2, Myb, CD10, CCDN3, and GCSAM) in the absence of BCL6 expression. Myc-induced activation of Myb mediates expression of many of these BL-associated proteins. We demonstrate that Myc blocks LMP1 expression both by inhibiting expression of cellular factors (STAT3 and Src) that activate LMP1 transcription and by increasing expression of proteins (DNMT3B and UHRF1) known to enhance DNA methylation of the LMP1 promoters in human BLs. These results show that latent EBV infection collaborates with Myc over-expression to induce BL-like human B-cell lymphomas in mice. As NF-κB signaling retards the growth of EBV-negative BLs, Myc-mediated repression of LMP1 may be essential for latent EBV infection and Myc translocation to collaboratively induce human BLs.

Nuclear autoantigenic sperm protein facilitates glioblastoma progression and radioresistance by regulating the ANXA2/STAT3 axis

AIMS

Although radiotherapy is a core treatment modality for various human cancers, including glioblastoma multiforme (GBM), its clinical effects are often limited by radioresistance. The specific molecular mechanisms underlying radioresistance are largely unknown, and the reduction of radioresistance is an unresolved challenge in GBM research.

METHODS

We analyzed and verified the expression of nuclear autoantigenic sperm protein (NASP) in gliomas and its relationship with patient prognosis. We also explored the function of NASP in GBM cell lines. We performed further mechanistic experiments to investigate the mechanisms by which NASP facilitates GBM progression and radioresistance. An intracranial mouse model was used to verify the effectiveness of combination therapy.

RESULTS

NASP was highly expressed in gliomas, and its expression was negatively correlated with the prognosis of glioma. Functionally, NASP facilitated GBM cell proliferation, migration, invasion, and radioresistance. Mechanistically, NASP interacted directly with annexin A2 (ANXA2) and promoted its nuclear localization, which may have been mediated by phospho-annexin A2 (Tyr23). The NASP/ANXA2 axis was involved in DNA damage repair after radiotherapy, which explains the radioresistance of GBM cells that highly express NASP. NASP overexpression significantly activated the signal transducer and activator of transcription 3 (STAT3) signaling pathway. The combination of WP1066 (a STAT3 pathway inhibitor) and radiotherapy significantly inhibited GBM growth in vitro and in vivo.

CONCLUSION

Our findings indicate that NASP may serve as a potential biomarker of GBM radioresistance and has important implications for improving clinical radiotherapy.

Design, synthesis, and biological evaluation of naphthoylamide derivatives as inhibitors of STAT3 phosphorylation

The phosphorylation of STAT3 plays a critical physiological role in the proliferation of rectal cancer. Hence, inhibiting STAT3 phosphorylation is an effective anticancer approach. In this work, we designed a novel 5-R'-1-naphthylmethylamide scaffold as a small molecule inhibitor of STAT3 phosphorylation. The results showed that 3D and 4D have exceptional inhibitory ability against three different colorectal cancer (CRC) cell lines, and can induce apoptosis of CRC cells by inhibiting STAT3 phosphorylation, while having no killing effect on normal human cells. 3D and 4D can inhibit STAT3 phosphorylation in a time- and concentration-dependent manner, and also inhibit the nuclear translocation of interleukin (IL)-6-induced STAT3. In the in vivo tumor model research, 4D significantly reduced the tumor volume of mice and had no drug toxicity on other organ tissues. Furthermore, molecular docking studies revealed that 3D and 4D had greater binding free energy when interacting with the STAT3 SH2 structural domain, and could establish H-π interaction modes. Dynamic simulation studies indicated that both compounds were able to bind tightly to STAT3.

JAK/STAT3 signaling in cardiac fibrosis: a promising therapeutic target

Cardiac fibrosis is a serious health problem because it is a common pathological change in almost all forms of cardiovascular diseases. Cardiac fibrosis is characterized by the transdifferentiation of cardiac fibroblasts (CFs) into cardiac myofibroblasts and the excessive deposition of extracellular matrix (ECM) components produced by activated myofibroblasts, which leads to fibrotic scar formation and subsequent cardiac dysfunction. However, there are currently few effective therapeutic strategies protecting against fibrogenesis. This lack is largely because the molecular mechanisms of cardiac fibrosis remain unclear despite extensive research. The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling cascade is an extensively present intracellular signal transduction pathway and can regulate a wide range of biological processes, including cell proliferation, migration, differentiation, apoptosis, and immune response. Various upstream mediators such as cytokines, growth factors and hormones can initiate signal transmission via this pathway and play corresponding regulatory roles. STAT3 is a crucial player of the JAK/STAT pathway and its activation is related to inflammation, malignant tumors and autoimmune illnesses. Recently, the JAK/STAT3 signaling has been in the spotlight for its role in the occurrence and development of cardiac fibrosis and its activation can promote the proliferation and activation of CFs and the production of ECM proteins, thus leading to cardiac fibrosis. In this manuscript, we discuss the structure, transactivation and regulation of the JAK/STAT3 signaling pathway and review recent progress on the role of this pathway in cardiac fibrosis. Moreover, we summarize the current challenges and opportunities of targeting the JAK/STAT3 signaling for the treatment of fibrosis. In summary, the information presented in this article is critical for comprehending the role of the JAK/STAT3 pathway in cardiac fibrosis, and will also contribute to future research aimed at the development of effective anti-fibrotic therapeutic strategies targeting the JAK/STAT3 signaling.

Farnesoid X receptor promotes non-small cell lung cancer metastasis by activating Jak2/STAT3 signaling via transactivation of IL-6ST and IL-6 genes

Metastasis accounts for the majority of cases of cancer recurrence and death in patients with advanced non-small cell lung cancer (NSCLC). Farnesoid X Receptor (FXR) is a bile acid nuclear receptor that was recently found to be upregulated in NSCLC tissues. However, whether and how FXR regulates NSCLC metastasis remains unclear. In the present study, it was found that FXR promoted the migration, invasion, and angiogenic ability of NSCLC cells in vitro, and increased NSCLC metastasis in a mouse model in vivo. Mechanistic investigation demonstrated that FXR specifically bound to the promoters of IL-6ST and IL-6 genes to upregulate their transcription, thereby leading to activation of the Jak2/STAT3 signaling pathway, which facilitated tumor migration, invasion, and angiogenesis in NSCLC. Notably, Z-guggulsterone, a natural FXR inhibitor, significantly reduced FXRhigh NSCLC metastasis, and decreased the expression of FXR, IL-6, IL-6ST, and p-STAT3 in the mouse model. Clinical analysis verified that FXR was positively correlated with IL-6, IL-6ST and p-STAT3 expression in NSCLC patients, and was indicative of a poor prognosis. Collectively, these results highlight a novel FXR-induced IL-6/IL-6ST/Jak2/STAT3 axis in NSCLC metastasis, and a promising therapeutic means for treating FXRhigh metastatic NSCLC.

Development of new thieno[2,3-d]pyrimidines as dual EGFR and STAT3 inhibitors endowed with anticancer and pro-apoptotic activities

In part due to the resilience of cellular feedback pathways that develop therapeutic resistance to targeting the EGFR alone, using EGFR inhibitors alone was demonstrated to be unsuccessful in clinical trials. The over-activation of the signal transducer/activator of transcription 3 (STAT3) during the administration of an EGFR inhibitor is expected to play a substantial part in the failure and resistance of EGFR inhibitor treatment. Therein, we proposed a hypothesis that induced STAT3-mediated resistance to EGFR inhibition therapy could be addressed by a dual inhibition of EGFR and STAT3 method. To this end, we tried to discover new thieno[2,3-d]pyrimidine derivatives "5a-o". Results from the screening on A549 and MCF7 cancer cell lines revealed that compounds 5j and 5k showed two-digit nanomolar with appropriate safety towards the WI-38 cell line. The best molecules, 5j and 5k, were subjected to γ-radiation, and their cytotoxic efficacy didn't change after irradiation, demonstrating that not having to use it avoided its side effects. Compounds 5j and 5k demonstrated the highest inhibition when their potency was tested as dual inhibitors on EGFR 67 and 41 nM, respectively, and STAT3 5.52 and 3.34 nM, respectively, proved with in silico molecular docking and dynamic simulation. In light of the results presented above, the capacity of both powerful compounds to alter the cell cycle and initiate the apoptotic process in breast cancer MCF7 cells was investigated. Caspase-8, Bcl-2, Bax and Caspase-9 apoptotic indicators were studied.

Asymmetric Synthesis of Saturated and Unsaturated Hydroxy Fatty Acids (HFAs) and Study of Their Antiproliferative Activity

Hydroxy fatty acids (HFAs) constitute a class of lipids, distinguished by the presence of a hydroxyl on a long aliphatic chain. This study aims to expand our insights into HFA bioactivities, while also introducing new methods for asymmetrically synthesizing unsaturated and saturated HFAs. Simultaneously, a procedure previously established by us was adapted to generate new HFA regioisomers. An organocatalytic step was employed for the synthesis of chiral terminal epoxides, which either by alkynylation or by Grignard reagents resulted in unsaturated or saturated chiral secondary alcohols and, ultimately, HFAs. 7-(S)-Hydroxyoleic acid (7SHOA), 7-(S)-hydroxypalmitoleic acid (7SHPOA) and 7-(R)- and (S)-hydroxymargaric acids (7HMAs) were synthesized for the first time and, together with regioisomers of (R)- and (S)-hydroxypalmitic acids (HPAs) and hydroxystearic acids (HSAs), whose biological activity has not been tested so far, were studied for their antiproliferative activities. The unsaturation of the long chain, as well as an odd-numbered (C17) fatty acid chain, led to reduced activity, while the new 6-(S)-HPA regioisomer was identified as exhibiting potent antiproliferative activity in A549 cells. 6SHPA induced acetylation of histone 3 in A549 cells, without affecting acetylated α-tubulin levels, suggesting the selective inhibition of histone deacetylase (HDAC) class I enzymes, and was found to inhibit signal transducer and activator of transcription 3 (STAT3) expression.

β-elemene enhances cisplatin sensitivity of non-small cell lung cancer cells via the miR-17-5p/STAT3 axis

In China, β-elemene, a sesquiterpene compound derived from Curcuma wenyujin, is clinically used to treat many human malignancies, including non-small cell lung cancer (NSCLC). Nonetheless, the role of β-elemene in regulating cisplatin sensitivity of NSCLC cells and the related mechanisms are not clear. This study was conducted to investigate the role of β-elemene in sensitizing NSCLC cells to cisplatin. In this work, cisplatin-resistant NSCLC cell lines were constructed. CCK-8, colony formation, and flow cytometry assays were executed to examine cell viability, growth, and apoptosis. MiR-17-5p and STAT3 expression levels in cells were detected by qRT-PCR. Western blot was executed to determine the expression levels of STAT3 and apoptosis-related proteins (Bax and Bcl-2) in the cells. Dual-luciferase reporter gene experiments were performed to verify the targeting relationship between miR-17-5p and STAT3. Herein, we report that, β-elemene inhibits the viability, and induces the apoptosis of cisplatin-resistant NSCLC cells. Additionally, β-elemene induces the upregulation miR-17-5p and downregulation of STAT3. STAT3 is validated to be a target of miR-17-5p in NSCLC cells. Additionally, the role of β-elemene to repress the viability of cisplatin-resistant NSCLC cells is partially counteracted by miR-17-5p inhibitor or STAT3 overexpression. In summary, our study suggests that β-elemene enhances cisplatin sensitivity of NSCLC cells by modulating miR-17-5p/STAT3 axis, and it may be a choice for the complementary treatment of NSCLC patients.

To Explore the Mechanism of Maiwei Dihuang Decoction in the Treatment of Non-small Cell Lung Cancer based on Network Pharmacology Combined with LC-MS

OBJECTIVE

To explore the mechanism of Maiwei Dihuang decoction in the treatment of non-small cell lung cancer (NSCLC) by using network pharmacology and LC-MS technology.

METHODS

The effective components in Maiwei Dihuang decoction were detected by liquid chromatography- mass spectrometry (LC-MS). Use the SuperPred database to collect the relevant targets of the active ingredients of Mai Wei Di Tang, and then collect the relevant targets of nonsmall cell lung cancer from GeneCards, DisgenNET and OMIM databases. On this basis, PPI network construction, GO enrichment analysis and KEGG pathway annotation analysis were carried out for target sites. Finally, AutoDock Vina is used for molecular docking.

RESULTS

We further screened 16 effective Chinese herbal compounds through LC-MS combined with ADME level. On this basis, we obtained 77 core targets through protein interaction network analysis. Through GO, KEGG analysis and molecular docking results, we finally screened out the potential targets of Maiwei Dihuang Decoction for NSCLC: TP53, STAT3, MAPK3.

CONCLUSION

Maiwei Dihuang decoction may play a role in the treatment of NSCLC by coregulating TP53/STAT3/MAPK3 signal pathway.

Targeting anticancer immunity in oral cancer: Drugs, products, and nanoparticles

Oral cavity carcinomas are the most frequent malignancies among head and neck malignancies. Oral tumors include not only oral cancer cells with different potency and stemness but also consist of diverse cells, containing anticancer immune cells, stromal and also immunosuppressive cells that influence the immune system reactions. The infiltrated T and natural killer (NK) cells are the substantial tumor-suppressive immune compartments in the tumor. The infiltration of these cells has substantial impacts on the response of tumors to immunotherapy, chemotherapy, and radiotherapy. Nevertheless, cancer cells, stromal cells, and some other compartments like regulatory T cells (Tregs), macrophages, and myeloid-derived suppressor cells (MDSCs) can repress the immune responses against malignant cells. Boosting anticancer immunity by inducing the immune system or repressing the tumor-promoting cells is one of the intriguing approaches for the eradication of malignant cells such as oral cancers. This review aims to concentrate on the secretions and interactions in the oral tumor immune microenvironment. We review targeting tumor stroma, immune system and immunosuppressive interactions in oral tumors. This review will also focus on therapeutic targets and therapeutic agents such as nanoparticles and products with anti-tumor potency that can boost anticancer immunity in oral tumors. We also explain possible future perspectives including delivery of various cells, natural products and drugs by nanoparticles for boosting anticancer immunity in oral tumors.

Induction of apoptotic cell death of cholangiocarcinoma cells by tiliacorinine from Tiliacora triandra: A mechanistic insight

BACKGROUND

Cholangiocarcinoma (CCA) exhibits poor response to the present chemotherapeutic agents and frequently develops drug resistance. Finding novel anticancer drugs might enhance patient outcomes. Tiliacorinine, a bisbenzylisoquinoline alkaloid from the Thai medicinal plant Tiliacora triandra, effectively induced apoptosis of human CCA cell lines and inhibited tumor growth in mice. Here, we elucidate further the molecular mechanisms underlining the cytotoxicity of tiliacorinine and its implication in overcoming gemcitabine-resistance of CCA cells.

METHODS

Cytotoxicity of tiliacorinine against CCA cell lines was assessed using MTT assay. The molecular signaling was determined using Western blot analysis. Molecular docking simulations were applied to predict the binding affinity and orientation of tiliacorinine to the possible binding site(s) of the target proteins.

RESULTS

Tiliacorinine induced apoptotic cell death of CCA cells in a dose- and time-dependent manner. Tiliacorinine significantly suppressed the expression of anti-apoptotic proteins, Bcl-xL and XIAP; activated apoptotic machinery proteins, caspase-3, caspase-9, and PARP; and decreased the levels of pAkt and pSTAT3. EGF/EGFR activation model and molecular docking simulations revealed EGFR, Akt, and STAT3 as potent targets of tiliacorinine. Molecular docking simulations indicated a strong binding affinity of tiliacorinine to the ATP-binding pockets of EGFR, PI3K, Akt, JAK2, and SH2 domain of STAT3. Tiliacorinine could synergize with gemcitabine and restore the cytotoxicity of gemcitabine against gemcitabine-resistant CCA cells.

CONCLUSION

Tiliacorinine effectively induced apoptosis via binding and blocking the actions of EGFR, Akt, and STAT3.

GENERAL SIGNIFICANCE

Tiliacorinine is a novel multi-kinase inhibitor and possibly a potent anti-cancer agent, in cancers with high activation of EGFR.

Mechanism of XiJiaQi in the treatment of chronic heart failure: Integrated analysis by pharmacoinformatics, molecular dynamics simulation, and SPR validation

OBJECTIVE

Chronic heart failure (CHF) is a complicated clinical syndrome with a high mortality rate. XiJiaQi (XJQ) is a traditional Chinese medicine used in the clinical treatment of CHF, but its bioactive components and their modes of action remain unknown. This study was designed to unravel the molecular mechanism of XJQ in the treatment of CHF using multiple computer-assisted and experimental methods.

METHODS

Pharmacoinformatics-based methods were used to explore the active components and targets of XJQ in the treatment of CHF. ADMETlab was then utilized to evaluate the pharmacokinetic and toxicological properties of core components. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were to explore the underlying mechanism of XJQ treatment. Molecular docking, surface plasmon resonance (SPR), and molecular dynamics (MD) were employed to evaluate the binding of active components to putative targets.

RESULTS

Astragaloside IV, formononetin, kirenol, darutoside, periplocin and periplocymarin were identified as core XJQ-related components, and IL6 and STAT3 were identified as core XJQ targets. ADME/T results indicated that periplocin and periplocymarin may have potential toxicity. GO and KEGG pathway analyses revealed that XJQ mainly intervenes in inflammation, apoptosis, diabetes, and atherosclerosis-related biological pathways. Molecular docking and SPR revealed that formononetin had a high affinity with IL6 and STAT3. Furthermore, MD simulation confirmed that formononetin could firmly bind to the site 2 region of IL6 and the DNA binding domain of STAT3.

CONCLUSION

This study provides a mechanistic rationale for the clinical application of XJQ. Modulation of STAT3 and IL-6 by XJQ can impact CHF, further guiding research efforts into the molecular underpinnings of CHF.

Potential drug repurposing of ruxolitinib to inhibit the JAK/STAT pathway for the treatment of patients with epithelial ovarian cancer

AIM

This review aimed to describe the potential for therapeutic targeting of the JAK/STAT signaling pathway by repurposing the clinically-approved JAK inhibitor ruxolitinib in the patients with epithelial ovarian cancer (OC) setting.

METHODS

We reviewed publications that focus on the inhibition of the JAK/STAT pathway in hematological and solid malignancies including OC.

RESULTS

Preclinical studies showed that ruxolitinib effectively reduces OC cell viability and metastasis and enhances the anti-tumor activity of chemotherapy drugs. There are a number of recent clinical trials exploring the role of JAK/STAT inhibition in solid cancers including OC. Early results have not adequately supported efficacy in solid tumors. However, there are preclinical data and clinical studies supporting the use of ruxolitinib in combination with both chemotherapy and other targeted drugs in OC setting.

CONCLUSION

Inflammatory conditions and persistent activation of the JAK/STAT pathway are associated with tumourigenesis and chemoresistance, and therapeutic blockade of this pathway shows promising results. For women with OC, clinical investigation exploring the role of ruxolitinib in combination with chemotherapy agents or other targeted therapeutics is warranted.

Impact of CRISPR/Cas9-Mediated CD73 Knockout in Pancreatic Cancer

Pancreatic cancer is among the cancers with the highest mortality rates. Most of the patients are found to have advanced cancer, losing the chance of surgical treatment, and there is an urgent need to find new treatment methods. Targeted therapy for specific genes that play a key role in cancer is now an important means to improve the survival rate of patients. We determined that CD73 is highly expressed in pancreatic cancer by flow cytometry and qRT-PCR assays combined with bioinformatics techniques. Application of CRISPR/Cas9 technology to knockout CD73 in human and murine cell lines, respectively, revealed that CD73 inactivation inhibited cell growth and migration and induced G1 cell cycle arrest. We also found that CD73 deletion inhibited the ERK/STAT3 pathway and activated the E-cadherin pathway. In addition, a CRISPR/Cas9 protein kinase library screen was performed and identified Pbk, Fastk, Cdk19, Adck5, Trim28, and Pfkp as possible genes regulating CD73.

Lung cancer treatment potential and limits associated with the STAT family of transcription factors

Lung cancer is one of the mortal cancers and the leading cause of cancer-related mortality, with a cancer survival rate of fewer than 5% in developing nations. This low survival rate can be linked to things like late-stage detection, quick postoperative recurrences in patients receiving therapy, and chemoresistance developing against various lung cancer treatments. Signal transducer and activator of transcription (STAT) family of transcription factors are involved in lung cancer cell proliferation, metastasis, immunological control, and treatment resistance. By interacting with specific DNA sequences, STAT proteins trigger the production of particular genes, which in turn result in adaptive and incredibly specific biological responses. In the human genome, seven STAT proteins have been discovered (STAT1 to STAT6, including STAT5a and STAT5b). Many external signaling proteins can activate unphosphorylated STATs (uSTATs), which are found inactively in the cytoplasm. When STAT proteins are activated, they can increase the transcription of several target genes, which leads to unchecked cellular proliferation, anti-apoptotic reactions, and angiogenesis. The effects of STAT transcription factors on lung cancer are variable; some are either pro- or anti-tumorigenic, while others maintain dual, context-dependent activities. Here, we give a succinct summary of the various functions that each member of the STAT family plays in lung cancer and go into more detail about the advantages and disadvantages of pharmacologically targeting STAT proteins and their upstream activators in the context of lung cancer treatment.

Targeting cGAS/STING signaling-mediated myeloid immune cell dysfunction in TIME

Myeloid immune cells (MICs) are potent innate immune cells serving as first responders to invading pathogens and internal changes to cellular homeostasis. Cancer is a stage of altered cellular homeostasis that can originate in response to different pathogens, chemical carcinogens, and internal genetic/epigenetic changes. MICs express several pattern recognition receptors (PRRs) on their membranes, cytosol, and organelles, recognizing systemic, tissue, and organ-specific altered homeostasis. cGAS/STING signaling is a cytosolic PRR system for identifying cytosolic double-stranded DNA (dsDNA) in a sequence-independent but size-dependent manner. The longer the cytosolic dsDNA size, the stronger the cGAS/STING signaling activation with increased type 1 interferon (IFN) and NF-κB-dependent cytokines and chemokines' generation. The present article discusses tumor-supportive changes occurring in the tumor microenvironment (TME) or tumor immune microenvironment (TIME) MICs, specifically emphasizing cGAS/STING signaling-dependent alteration. The article further discusses utilizing MIC-specific cGAS/STING signaling modulation as critical tumor immunotherapy to alter TIME.

Research progress of STAT3-based dual inhibitors for cancer therapy

Signal transducer and activator of transcription 3 (STAT3), a transcription factor, regulates gene levels that are associated with cell survival, cell cycle, and immune reaction. It is correlated with the grade of malignancy and the development of various cancers and targeting STAT3 protein is a potentially promising therapeutic strategy for tumors. Over the past 20 years, various compounds have been found to directly inhibit STAT3 activity via different strategies. However, numerous difficulties exist in the development of STAT3 inhibitors, such as serious toxic effects, poor therapeutic effects, and intrinsic and acquired drug resistance. STAT3 inhibitors synergistically suppress cancer development with additional anti-tumor drugs, such as indoleamine 2,3-dioxygenase 1 inhibitors (IDO1i), histone deacetylase inhibitors (HDACi), DNA inhibitors, pro-tumorigenic cytokine inhibitors (PTCi), NF-κB inhibitors, and tubulin inhibitors. Therefore, individual molecule- based dual-target inhibitors can be the candidate alternative or complementary treatment to overcome the disadvantages of just STAT3 or other targets as a monotherapy. In this review, we discuss the theoretical basis for formulating STAT3-based dual-target inhibitors and also summarize their structure-activity relationships (SARs).

A Novel Ageladine A Derivative Acts as a STAT3 Inhibitor and Exhibits Potential Antitumor Effects

The Janus kinase/signal transducer and activator of the transcription 3 (JAK/STAT3) signaling pathway controls multiple biological processes, including cell survival, proliferation, and differentiation. Abnormally activated STAT3 signaling promotes tumor cell growth, proliferation, and survival, as well as tumor invasion, angiogenesis, and immunosuppression. Hence, JAK/STAT3 signaling has been considered a promising target for antitumor therapy. In this study, a number of ageladine A derivative compounds were synthesized. The most effective of these was found to be compound 25. Our results indicated that compound 25 had the greatest inhibitory effect on the STAT3 luciferase gene reporter. Molecular docking results showed that compound 25 could dock into the STAT3 SH2 structural domain. Western blot assays demonstrated that compound 25 selectively inhibited the phosphorylation of STAT3 on the Tyr705 residue, thereby reducing STAT3 downstream gene expression without affecting the expression of the upstream proteins, p-STAT1 and p-STAT5. Compound 25 also suppressed the proliferation and migration of A549 and DU145 cells. Finally, in vivo research revealed that 10 mg/kg of compound 25 effectively inhibited the growth of A549 xenograft tumors with persistent STAT3 activation without causing significant weight loss. These results clearly indicate that compound 25 could be a potential antitumor agent by inhibiting STAT3 activation.

Sulconazole induces PANoptosis by triggering oxidative stress and inhibiting glycolysis to increase radiosensitivity in esophageal cancer

Esophageal cancer is the seventh most common cancer in the world. Although traditional treatment methods such as radiotherapy and chemotherapy have good effects, their side effects and drug resistance remain problematic. The repositioning of drug function provides new ideas for the research and development of anticancer drugs. We previously showed that the Food and Drug Administration (FDA)-approved drug sulconazole can effectively inhibit the growth of esophageal cancer cells, but its molecular mechanism is not clear. Here, our study demonstrated that sulconazole had a broad spectrum of anticancer effects. It can not only inhibit the proliferation, but also inhibit the migration of esophageal cancer cells. Both transcriptomic sequencing and proteomic sequencing showed that sulconazole could promote various types of programmed cell death and inhibit glycolysis and its related pathways. Experimentally, we found that sulconazole induced apoptosis, pyroptosis, necroptosis and ferroptosis. Mechanistically, sulconazole triggered mitochondrial oxidative stress and inhibited glycolysis. Finally, we showed that low-dose sulconazole can increase radiosensitivity of esophageal cancer cells. Taken together, these new findings provide strong laboratory evidence for the clinical application of sulconazole in esophageal cancer.

Tempol differential effect on prostate cancer inflammation: In vitro and in vivo evaluation

BACKGROUND

Tempol is a redox-cycling nitroxide that acts directly on inflammation. However, few studies have reported the use of tempol in prostate cancer (PCa). The present study investigated the effects of tempol on inflammation related to NF-κB signaling, using hormone-dependent or hormone-independent cell lines and the transgenic adenocarcinoma of the mouse prostate PCa animal model in the early and late stages of cancer progression.

METHODS

PC-3 and LnCaP cells were exposed to different tempol doses in vitro, and cell viability assays were performed. The optimal treatment dose was chosen for subsequent analysis using western blotting. Five experimental groups were evaluated in vivo to test for tempol effects in the early (CT12 and TPL12 groups) and late stages (CT20, TPL20-I, and TLP20-II) of PCa development. The TPL groups were treated with 50 or 100 mg/kg tempol. All control groups received water as the vehicle. The ventral lobe of the prostate was collected and subjected to immunohistochemical and western blot analysis.

RESULTS

Tempol treatment reduced cellular proliferation in vitro and improved prostatic morphology in vivo, thereby decreasing tumor progression. Tempol reduced inflammation in preclinical models, and downregulated the initial inflammatory signaling through toll-like receptors, not always mediated by the MyD88 pathway. In addition, it upregulated iκB-α and iκB -β levels, leading to a decrease in NF-κB, TNF-α, and other inflammatory markers. Tempol also influenced cell survival markers.

CONCLUSIONS

Tempol can be considered a beneficial therapy for PCa treatment owing to its anti-inflammatory and antiproliferative effects. Nevertheless, the action of tempol was different depending on the degree of the prostatic lesion in vivo and hormone reliance in vitro. This indicates that tempol plays a multifaceted role in the prostatic tissue environment.

Nifuroxazide inhibits the growth of glioblastoma and promotes the infiltration of CD8 T cells to enhance antitumour immunity

INTRODUCTION

Glioblastoma is a primary intracranial tumour with extremely high disability and fatality rates among adults. Existing diagnosis and treatment methods have not significantly improved the overall poor prognosis of patients. Nifuroxazide, an oral antibiotic, has been reported to act as a tumour suppressor in a variety of tumours and to participate in the process of antitumour immunity. However, whether it can inhibit the growth of glioma is still unclear.

METHODS

We explored the potential mechanism of nifuroxazide inhibiting the growth of glioblastoma cells through in vitro and in vivo experiments.

RESULTS

nifuroxazide can inhibit the proliferation of glioblastoma cells, promote G2 phase arrest, induce apoptosis, and inhibit epithelial-mesenchymal transition through the MAP3K1/JAK2/STAT3 pathway. Similarly, clinical sample analysis confirmed that MAP3K1 combined with STAT3 can affect the prognostic characteristics of patients with glioma. In addition, nifuroxazide can drive the M1 polarization of microglioma cells, inhibit the expression of CTLA4 and PD-L1 in tumour cells, and promote the infiltration of CD8 T cells to exert antitumour effects. Combination treatment with PD-L1 inhibitors can significantly prolong the survival time of mice.

CONCLUSION

we found that nifuroxazide can inhibit the growth of glioblastoma and enhance antitumour immunity. Thus, nifuroxazide is an effective drug for the treatment of glioblastoma and has great potential for clinical application.

STAT3 as a therapeutic target in the metformin-related treatment

Signal transducers and activators of transcription 3 (STAT3) signaling plays an important role in mediating tumor progression, inflammation, cardiovascular disease, and other pathological processes.In recent years, STAT3 as a therapeutic target has received extensive attention. It is well known that metformin can play the role of hypoglycemia by activating AMP-activated protein kinase (AMPK) through inhibition of mitochondrial ATP production.However, AMPK is not required for metformin activity.Although the application of STAT3 as a therapeutic target of metformin is still in the initial research stage, the importance of STAT3 in the mechanism of metformin is gradually being recognizedand further studies are needed to demonstrate the important role of the STAT3 regulatory network in the regulation of diseases by metformin. Here, we reviewed in detail that metformin inhibits the progression of various diseases like tumors, autoimmune diseases and hormone-related diseases by regulating multiple signaling pathways such as JAK/STAT3 and mTOR/STAT3 signaling centered on STAT3. We also summarized recent advances of STAT3 inhibitors combined with metformin in the treatment of diseases.We emphasized that STAT3 signaling, as an AMPK-independent signaling pathway, may be an important target for metformin in clinical therapy.

A comprehensive overview of Artemisinin and its derivatives as anticancer agents

Artemisinin is the crucial ingredient of artemisia annua, a traditional Chinese medicine used for the therapy of malaria in China for hundreds of years. In recent years, the anticancer properties of artemisinin and its derivatives have also been reported. This review has summarized the research and development of artemisinin and its derivatives as anticancer agents, which included both natural and synthetic monomers as well as their dimers. In addition, it highlights the antitumor effects of artemisinin and its derivatives after site-modification or after transformation to a nano-delivery system. Moreover, we have further explored their potential mechanisms of action and also discussed the clinical trials of ARTs used to treat cancer, which will facilitate in further development of novel anticancer drugs based on the scaffold of artemisinin.

Discovery of new STAT3 inhibitors as anticancer agents using ligand-receptor contact fingerprints and docking-augmented machine learning

STAT3 belongs to a family of seven vital transcription factors. High levels of STAT3 are detected in several types of cancer. Hence, STAT3 inhibition is considered a promising therapeutic anti-cancer strategy. In this work, we used multiple docked poses of STAT3 inhibitors to augment training data for machine learning QSAR modeling. Ligand-Receptor Contact Fingerprints and scoring values were implemented as descriptor variables. Escalating docking-scoring consensus levels were scanned against orthogonal machine learners, and the best learners (Random Forests and XGBoost) were coupled with genetic algorithm and Shapley additive explanations (SHAP) to identify critical descriptors that determine anti-STAT3 bioactivity to be translated into pharmacophore model(s). Two successful pharmacophores were deduced and subsequently used for in silico screening against the National Cancer Institute (NCI) database. A total of 26 hits were evaluated in vitro for their anti-STAT3 bioactivities. Out of which, three hits of novel chemotypes, showed cytotoxic IC50 values in the nanomolar range (35 nM to 6.7 μM). However, two are potent dihydrofolate reductase (DHFR) inhibitors and therefore should have significant indirect STAT3 inhibitory effects. The third hit (cytotoxic IC50 = 0.44 μM) is purely direct STAT3 inhibitor (devoid of DHFR activity) and caused, at its cytotoxic IC50, more than two-fold reduction in the expression of STAT3 downstream genes (c-Myc and Bcl-xL). The presented work indicates that the concept of data augmentation using multiple docked poses is a promising strategy for generating valid machine learning models capable of discriminating active from inactive compounds.

Bioinformatics analysis of miRNA and its associated genes to identify potential biomarkers of oral submucous fibrosis and oral malignancy

BACKGROUND

MicroRNAs are a group of non-coding RNA that controls the gene expression. The interaction between miRNA and mRNA is thought to be dynamic. Oral cancer "The cancer of mouth" is quite prevailing in developing countries. miRNA has been found associated with oral cancer targeting tumor growth, cell proliferation, metastasis, invasion. The significant association of miRNA with genes could be used as a remarkable tool for diagnosis as well as prognostic analysis of oral cancer.

AIM

The aim of the present study is to evaluate common upregulated and downregulated miRNAs in oral submucous fibrosis (OSMF) and oral malignancy (OM) patients that can be used as diagnostic biomarkers, and to find out their interactions with target genes to establish associated networks in cancer pathways.

METHODS AND RESULTS

Using miRDeep2 and DESeq analysis, the upregulated and downregulated miRNA in OSMF (Oral Submucous Fibrosis) and OM (Oral Malignancies) samples were compared to GEO (Gene Expression Omnibus) control dataset. There were 50 common downregulated miRNAs and 13 common upregulated miRNAs in OSMF and OM samples. miRNet analysis of common upregulated miRNA and common downregulated miRNA identified 1295 and 5954 genes, respectively connected with cancer pathways. From analysis of Hub genes, HRAS, STAT3, TP53, MYC, PTEN, CTNNB1, CCND1, JUN, VEGFA, KRAS were found associated with downregulated miRNA and VEGFA, TP53, MDM2, PTEN, MYC, ERBB2, CDKN1A, HSP90AA1, CCND1, AKTI were found associated with upregulated miRNA. The gene enrichment analysis of these hub genes were associated with cell communication, metabolic process, cell proliferation, and cellular component organization. Hub Genes linked with upregulated miRNA had an enrichment ratio of 11.828, whereas hub genes linked with downregulated miRNA had an enrichment ratio of 45.912.

CONCLUSION

We identified common deregulated miRNAs between OSMF and OM patients, which were further analyzed to find out associations with the genes correlated to cancer pathways. The hub genes identified in this study were found to have a significant impact on tumor growth and carcinogenesis. Also, the enrichment of these genes has revealed that the genes are associated with cellular communication, metabolic processes and various biological regulation. These deregulated miRNAs can be used to make a panel of biomarkers to diagnose oral cancer from blood even before its onset.

De Novo Design of Imidazopyridine-Tethered Pyrazolines That Target Phosphorylation of STAT3 in Human Breast Cancer Cells

In breast cancer (BC), STAT3 is hyperactivated. This study explored the design of imidazopyridine-tethered pyrazolines as a de novo drug strategy for inhibiting STAT3 phosphorylation in human BC cells. This involved the synthesis and characterization of two series of compounds namely, 1-(3-(2,6-dimethylimidazo [1,2-a]pyridin-3-yl)-5-(3-nitrophenyl)-4,5-dihydro-1H-pyrazol-1-yl)-2-(4-(substituted)piperazin-1-yl)ethanone and N-substituted-3-(2,6-dimethylimidazo[1,2-a]pyridin-3-yl)-5-(3-nitrophenyl)-4,5-dihydro-1H-pyrazoline-1-carbothioamides. Compound 3f with 2,3-dichlorophenyl substitution was recognized among the tested series as a lead structure that inhibited the viability of MCF-7 cells with an IC₅₀ value of 9.2 μM. A dose- and time-dependent inhibition of STAT3 phosphorylation at Tyr705 and Ser727 was observed in MCF-7 and T47D cells when compound 3f was added in vitro. Calculations using density functional theory showed that the title compounds HOMOs and LUMOs are situated on imidazopyridine-pyrazoline and nitrophenyl rings, respectively. Hence, compound 3f effectively inhibited STAT3 phosphorylation in MCF-7 and T47D cells, indicating that these structures may be an alternative synthon to target STAT3 signaling in BC.

Salicylanilides and Their Anticancer Properties

Salicylanilides are pharmacologically active compounds with a wide spectrum of biological effects. Halogenated salicylanilides, which have been used for decades in human and veterinary medicine as anthelmintics, have recently emerged as candidates for drug repurposing in oncology. The most prominent example of salicylanilide anthelmintic, that is intensively studied for its potential anticancer properties, is niclosamide. Nevertheless, recent studies have discovered extensive anticancer potential in a number of other salicylanilides. This potential of their anticancer action is mediated most likely by diverse mechanisms of action such as uncoupling of oxidative phosphorylation, inhibition of protein tyrosine kinase epidermal growth factor receptor, modulation of different signaling pathways as Wnt/β-catenin, mTORC1, STAT3, NF-κB and Notch signaling pathways or induction of B-Raf V600E inhibition. Here we provide a comprehensive overview of the current knowledge about the proposed mechanisms of action of anticancer activity of salicylanilides based on preclinical in vitro and in vivo studies, or structural requirements for such an activity.

Discovery of potential inhibitors for stat3: ligand based 3D pharmacophore, virtual screening, molecular docking, dynamic studies and in vitro evaluation

A large analysis of the signal transducer and activator of transcription (STAT3) in cancer is currently being carried out. It regulates gene expression, which is required for normal cellular functions such as differentiation, cell growth, proliferation, survival, maturation, and immunity. A ligand-based pharmacophore model was created using 3 D QSAR pharmacophore generation methodology in Discovery studio 4.1 clients to imagine structurally diverse novel chemical entities as STAT3 inhibitors with improved efficacy. Chemical properties of 48 different derivatives were included in the training package. Hypo1 was chosen as the query model for screening 1,45,000 drug-like molecules from the SPECS database, with these molecules subjected to the Lipinski rule of 5, Verber's rule, and SMART filtration. After filtration, the molecule was examined further using molecular docking analysis on the active site of STAT3. The binding interaction(s) and pharmacophore mapping were used to select the 19 possible inhibitory molecules. These 19 hits were then tested for toxicity using the TOPKAT software. In MD simulations and MM-PBSA calculations, the tested compound specs 28 provided the best results, suggesting that this ligand has the ability to inhibit more effectively. Based in-silico finding 19 compounds are subjected to in vitro anticancer activity against MDA-MB-231 and MCF-7 cell lines. Based on results compounds specs 11 and specs 13 shows significant activity compared to other compounds and these compounds were subjected to apoptosis assay. The tested compounds induced morphologic changes were dose and time dependent by which all the tested compound exhibits stronger anti-tumor effects.Communicated by Ramaswamy H. Sarma.

N-Rich, Polyphenolic Porous Organic Polymer and Its In Vitro Anticancer Activity on Colorectal Cancer

N-rich organic materials bearing polyphenolic moieties in their building networks and nanoscale porosities are very demanding in the context of designing efficient biomaterials or drug carriers for the cancer treatment. Here, we report the synthesis of a new triazine-based secondary-amine- and imine-linked polyphenolic porous organic polymer material TrzTFPPOP and explored its potential for in vitro anticancer activity on the human colorectal carcinoma (HCT 116) cell line. This functionalized (-OH, -NH-, -C=N-) organic material displayed an exceptionally high BET surface area of 2140 m2 g-1 along with hierarchical porosity (micropores and mesopores), and it induced apoptotic changes leading to high efficiency in colon cancer cell destruction via p53-regulated DNA damage pathway. The IC30, IC50, and IC70 values obtained from the MTT assay are 1.24, 3.25, and 5.25 μg/mL, respectively.

Clinicopathological Significance of STAT3 and p-STAT3 among 91 Patients with Adenocarcinoma of the Esophagogastric Junction

Adenocarcinoma of the esophagogastric junction (AEG) has increased rapidly worldwide during the last few decades. The purpose of this study is to investigate the clinical and prognostic characteristics of signal transduction and activator of transcription factor 3(STAT3) and phosphorylated STAT3 (p-STAT3) expression in AEG patients. We retrospectively analyzed the immunohistochemical results of 61 AEG patients and followed up for 5 years, while Western blot was performed on tissues from another 30 AEG patients. The results showed that STAT3 and p-STAT3 were overexpressed in AEG tissues (P < 0.05, P < 0.01). The high expression of STAT3 was significantly associated with the pTNM stage (P < 0.05), and the increased expression of p-STAT3 was significantly associated with depth of invasion (pT), lymph node metastasis (pN), and pTNM stage (P < 0.05, P < 0.05, P < 0.05). The 5-year survival rate for AEG patients was 41.0% and was significantly associated with tumor differentiation, pN, pTNM, and p-STAT3 (P < 0.05, P < 0.01, P < 0.05, P < 0.01). Cox regression analysis confirmed that tumor differentiation, pN, and high expression of p-STAT3 were independent risk factors for the 5-year survival rate in patients with AEG (P < 0.05, P < 0.01, P < 0.05). Our study showed that STAT3 and p-STAT3 play a critical role in AEG development.

Cell death affecting the progression of gastric cancer

Gastric cancer is a gastrointestinal tumor with high morbidity and mortality rates. Several factors influence its progression, cell death being an important element. In this review, we summarized the effects of necrosis, apoptosis, necroptosis, pyroptosis, ferroptosis, and eight less common cell death modalities on gastric cancer cells and the tumor microenvironment, detailed the molecular mechanisms of various cell death and their major regulatory pathways in gastric cancer, explored the prevalence and complexity of cell death in gastric cancer progression and highlighted the potentials of cell death-related therapies in gastric cancer.

LLL12B, a Novel Small-Molecule STAT3 Inhibitor, Induces Apoptosis and Suppresses Cell Migration and Tumor Growth in Triple-Negative Breast Cancer Cells

Persistent STAT3 signaling plays a pivotal role in human tumor malignancy, including triple-negative breast cancer (TNBC). There are few treatment options currently available for TNBC; thus, given its importance to cancer, STAT3 is a potential cancer therapeutic target and is the focus of drug discovery efforts. In this study, we tested a novel orally bioavailable small-molecule STAT3 inhibitor, LLL12B, in human MDA-MB-231, SUM159, and murine 4T1 TNBC cell lines. TNBC cells frequently expressed persistent STAT3 phosphorylation and their cell viability was sensitive to STAT3 knockdown by siRNA. LLL12B selectively inhibited the IL-6-mediated induction of STAT3 phosphorylation, but had little effect on the IFN-γ-mediated induction of STAT1 phosphorylation nor the EGF-mediated induction of ERK phosphorylation. In addition, targeting STAT3 with LLL12B induced apoptosis, reduced colony formation ability, and inhibited cell migration in TNBC cells. Furthermore, LLL12B suppressed the tumor growth of the MDA-MB-231 TNBC cells in a mammary fat pad mouse tumor model in vivo. Together, our findings support the concept that targeting persistent STAT3 signaling using the novel small-molecule LLL12B is a potential approach for TNBC therapy.

Roads to Stat3 Paved with Cadherins

The engagement of cadherins, cell-to-cell adhesion proteins, triggers a dramatic increase in the levels and activity of the Rac/Cdc42 GTPases, through the inhibition of proteasomal degradation. This leads to an increase in transcription and secretion of IL6 family cytokines, activation of their common receptor, gp130, in an autocrine manner and phosphorylation of the signal transducer and activator of transcription-3 (Stat3) on tyrosine-705 by the Jak kinases. Stat3 subsequently dimerizes, migrates to the nucleus and activates the transcription of genes involved in cell division and survival. The Src oncogene also increases Rac levels, leading to secretion of IL6 family cytokines and gp130 activation, which triggers a Stat3-ptyr705 increase. Interestingly, at the same time, Src downregulates cadherins in a quantitative manner, while cadherins are required to preserve gp130 levels for IL6 family signalling. Therefore, a fine balance between Src527F/Rac/IL6 and Src527F/cadherin/gp130 levels is in existence, which is required for Stat3 activation. This further demonstrates the important role of cadherins in the activation of Stat3, through preservation of gp130 function. Conversely, the absence of cadherin engagement correlates with low Stat3 activity: In sparsely growing cells, both gp130 and Stat3-ptyr705 levels are very low, despite the fact that cSrc is active in the FAK (focal adhesion kinase)/cSrc complex, which further indicates that the engagement of cadherins is important for Stat3 activation, not just their presence. Furthermore, the caveolin-1 protein downregulates Stat3 through binding and sequestration of cadherins to the scaffolding domain of caveolin-1. We hypothesize that the cadherins/Rac/gp130 axis may be a conserved pathway to Stat3 activation in a number of systems. This fact could have significant implications in Stat3 biology, as well as in drug testing and development.

Overexpression of miR-125a-5p Inhibits Hepatocyte Proliferation through the STAT3 Regulation In Vivo and In Vitro

microRNAs (miRNAs) are critically involved in liver regeneration (LR). miR-125a-5p (miR-125a) is a tumor-suppressing miRNA, but its role in LR has not been studied. Our previous studies have proved that miR-125a was related to LR at the initiation phase, while the mechanism hepatocyte proliferation triggered by miR-125a in LR has been rarely evaluated. Herein, we mainly studied the molecular mechanism of miR-125a in triggering hepatocyte proliferation and the proliferation stage of LR. Firstly, a striking reduction of miR-125a was found at 24 h as well as 30 h following partial hepatectomy (PH) in rat liver tissue by miRNAs expression profiles as well as qRT-PCR analysis. Furthermore, in vitro, upregulation of miR-125a decreased proliferation as well as G1/S conversion, which promoted hepatocytes apoptosis. STAT3 was the target of miR-125a. In vivo, upregulation of miR-125a by tail vein injection of agomir inhibited LR index. Upregulation of miR-125a inhibited LR index and hepatocytes proliferation by STAT3/p-STAT3/JUN/BCL2 axis. In summary, these current discoveries indicated that miR-125a inhibited hepatocytes proliferation as well as LR by targeting STAT3 and via acting on the STAT3/p-STAT3/JUN/BCL2 axis.

Pinus mugo Essential Oil Impairs STAT3 Activation through Oxidative Stress and Induces Apoptosis in Prostate Cancer Cells

Essential oils (EOs) and their components have been reported to possess anticancer properties and to increase the sensitivity of cancer cells to chemotherapy. The aim of this work was to select EOs able to downregulate STAT3 signaling using Western blot and RT-PCR analyses. The molecular mechanism of anti-STAT3 activity was evaluated through spectrophotometric and fluorometric analyses, and the biological effect of STAT3 inhibition was analyzed by flow cytometry and wound healing assay. Herein, Pinus mugo EO (PMEO) is identified as an inhibitor of constitutive STAT3 phosphorylation in human prostate cancer cells, DU145. The down-modulation of the STAT3 signaling cascade decreased the expression of anti-proliferative as well as anti-apoptotic genes and proteins, leading to the inhibition of cell migration and apoptotic cell death. PMEO treatment induced a rapid drop in glutathione (GSH) levels and an increase in reactive oxygen species (ROS) concentration, resulting in mild oxidative stress. Pretreatment of cells with N-acetyl-cysteine (NAC), a cell-permeable ROS scavenger, reverted the inhibitory action of PMEO on STAT3 phosphorylation. Moreover, combination therapy revealed that PMEO treatment displayed synergism with cisplatin in inducing the cytotoxic effect. Overall, our data highlight the importance of STAT3 signaling in PMEO cytotoxic activity, as well as the possibility of developing adjuvant therapy or sensitizing cancer cells to conventional chemotherapy.

Inhibiting STAT3 signaling pathway by natural products for cancer prevention and therapy: In vitro and in vivo activity and mechanisms of action

Signal transducer and activator of transcription 3 (STAT3) plays a critical role in signal transmission from the plasma membrane to the nucleus, regulating the expression of genes involved in essential cell functions and controlling the processes of cell cycle progression and apoptosis. Thus, STAT3 has been elucidated as a promising target for developing anticancer drugs. Many natural products have been reported to inhibit the STAT3 signaling pathway during the past two decades and have exhibited significant anticancer activities in vitro and in vivo. However, there is no FDA-approved STAT3 inhibitor yet. The major mechanisms of these natural product inhibitors of the STAT3 signaling pathway include targeting the upstream regulators of STAT3, directly binding to the STAT3 SH2 domain and inhibiting its activation, inhibiting STAT3 phosphorylation and/or dimerization, and others. In the present review, we have systematically discussed the development of these natural product inhibitors of STAT3 signaling pathway as well as their in vitro and in vivo anticancer activity and mechanisms of action. Outlooks and perspectives on the associated challenges are provided as well.

Preliminary study on the role and mechanism of KIRREL3 in the development of esophageal squamous cell carcinoma

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a common malignant tumor of the digestive tract, which is very harmful to human health. The JAK-STAT signaling pathway is a recognized carcinogenic pathway that plays a role in the proliferation, apoptosis, migration, and invasion of a variety of cancer cells. Some studies have shown that the activation status of STAT3 affects the expression of KIRREL3. However, the expression of KIRREL3 in ESCC and its relationship with KIRREL3 or the JAK-STAT signaling pathway is still unclear.

METHODS

In this study, we used immunohistochemistry and western blotting to analyze the protein expression levels of KIRREL3 in tumor tissues and ESCC cell lines. We applied proliferation assays, plate clone formation assays, Transwell assays, flow cytometry analysis, and CDX animal models to examine the role of KIRREL3 in ESCC.

RESULTS

The results indicate that KIRREL3 is highly expressed to varying degrees in ESCC tissues and cell lines. Knocking down KIRREL3 expression in ESCC cells could correspondingly inhibit cell proliferation, colony formation, invasion, and migration, and had some effects on cell cycle progression and apoptosis. In addition, overexpressing KIRREL3 in these cells had opposite effects. Tumor formation in nude mice experiments also confirmed that KIRREL3 is involved in the growth of ESCC cells in vivo.

CONCLUSIONS

These data suggest that KIRREL3 plays a key role in the development of ESCC, and KIRREL3 is a potential new target for the early diagnosis and clinical treatment of this disease.

STAT3 mediates RCP-induced cancer cell invasion through the NF-κB/Slug/MT1-MMP signaling cascade

Rab coupling protein (RCP) has been known to induce cancer invasion and metastasis, and STAT3 is one of major oncogenic factors. In the present study, we identify the critical role of STAT3 in RCP-induced cancer cell invasion. Immunohistochemical data of ovarian cancer tissues presented that levels of RCP expression are closely correlated with those of phospho-STAT3 (p-STAT3). In addition, ovarian cancer patients with high expression of both RCP and p-STAT3 had significantly lower progress-free and overall survival rates compared to those with low either RCP or p-STAT3 expression. Mechanistically, RCP induced STAT3 phosphorylation in both ovarian and breast cancer cells. Silencing or pharmacological inhibition of STAT3 significantly inhibited RCP-induced cancer cell invasion. In addition, we provide evidence that the β1 integrin/EGFR axis is important for RCP-induced STAT3 phosphorylation. Furthermore, STAT3 activated NF-κB for Slug expression that in turn upregulated MT1-MMP expression for cancer cell invasion. Collectively, our present data demonstrate that STAT3 is located downstream of the β1 integrin/EGFR axis and induces Slug and MT1-MMP expression for cancer cell invasion.

A Broad-Based Characterization of a Cell-Penetrating, Single Domain Camelid Bi-Specific Antibody Monomer That Targets STAT3 and KRAS Dependent Cancers

STAT3 and KRAS regulate cell proliferation, survival, apoptosis, cell migration, and angiogenesis. Aberrant expression of STAT3 and mutant active forms of KRAS have been well-established in the induction and maintenance of multiple cancers. STAT3 and KRAS mutant proteins have been considered anti-cancer targets; however, they are also considered to be clinically “undruggable” intracellular molecules, except for KRAS(G12C). Here we report a first-in-class molecule, a novel, single domain camelid VHH antibody (15 kDa), SBT-100, that binds to both STAT3 and KRAS and can penetrate the tumor cell membrane, and significantly inhibit cancer cell growth. Additionally, SBT-100 inhibits KRAS GTPase activity and downstream phosphorylation of ERK in vitro. In addition, SBT-100 inhibits the growth of multiple human cancers in vitro and in vivo. These results demonstrate the feasibility of targeting hard-to-reach aberrant intracellular transcription factors and signaling proteins simultaneously with one VHH to improve cancer therapies.