Brassinin inhibits STAT3 signaling pathway through modulation of PIAS-3 and SOCS-3 expression and sensitizes human lung cancer xenograft in nude mice to paclitaxel

A strategic review of STAT3 signaling inhibition by phytochemicals for cancer prevention and treatment: Advances and insights

Cancer remains a significant global health concern. The dysregulation of signaling networks in tumor cells greatly affects their functions. This review intends to explore phytochemicals possessing potent anticancer properties that specifically target the STAT3 signaling pathway, elucidating strategies and emphasizing their potential as promising candidates for cancer therapy. The review comprehensively examines various STAT3 inhibitors designed to disrupt the signaling cascade, including those targeting upstream activation, SH2 domain phosphorylation, DNA binding domain (DBD), N-terminal domain (NTD), nuclear translocation, and enhancing endogenous STAT3 negative regulators. A literature review was conducted to identify phytochemicals with anticancer activity targeting the STAT3 signaling pathway. Popular research databases such as Google Scholar, PubMed, Science Direct, Scopus, Web of Science, and ResearchGate were searched from the years 1989 - 2023 based on the keywords "Cancer", "STAT3", "Phytochemicals", "Phytochemicals targeting STAT3 signaling", "upstream activation of STAT3", "SH2 domain of STAT3", "DBD of STAT3", "NTD of STAT3, "endogenous negative regulators of STAT3", or "nuclear translocation of STAT3", and their combinations. A total of 264 relevant studies were selected and analyzed based on the mechanisms of action and the efficacy of the phytocompounds. The majority of the discussed phytochemicals primarily focus on inhibiting upstream activation of STAT3. Additionally, flavonoid and terpenoid compounds exhibit multifaceted effects by targeting one or more checkpoints within the STAT3 pathway. Analysis reveals that phytochemicals targeting upstream activation predominantly belong to the classes of flavonoids and terpenoids, which hold significant promise as effective anticancer therapeutics. Future research in this field can be directed towards exploring and developing these scrutinized classes of phytochemicals to achieve desired therapeutic outcomes in cancer treatment.

STAT3 Protein-Protein Interaction Analysis Finds P300 as a Regulator of STAT3 and Histone 3 Lysine 27 Acetylation in Pericytes

BACKGROUND

Signal transducer and activator of transcription 3 (STAT3) is a member of the cytoplasmic inducible transcription factors and plays an important role in mediating signals from cytokines, chemokines, and growth factors. We and others have found that STAT3 directly regulates pro-fibrotic signaling in the kidney. The STAT3 protein-protein interaction plays an important role in activating its transcriptional activity. It is necessary to identify these interactions to investigate their function in kidney disease. Here, we investigated the protein-protein interaction among three species to find crucial interactions that can be targeted to alleviate kidney disease.

METHOD

In this study, we examined common protein-protein interactions leading to the activation or downregulation of STAT3 among three different species: humans (Homo sapiens), mice (Mus musculus), and rabbits (Oryctolagus cuniculus). Further, we chose to investigate the P300 and STAT3 interaction and performed studies of the activation of STAT3 using IL-6 and inhibition of the P300 by its specific inhibitor A-485 in pericytes. Next, we performed immunoprecipitation to confirm whether A-485 inhibits the binding of P300 to STAT3.

RESULTS

Using the STRING application from ExPASy, we found that six proteins, including PIAS3, JAK1, JAK2, EGFR, SRC, and EP300, showed highly confident interactions with STAT3 in humans, mice, and rabbits. We also found that IL-6 treatment increased the acetylation of STAT3 and increased histone 3 lysine acetylation (H3K27ac). Furthermore, we found that the disruption of STAT3 and P300 interaction by the P300 inhibitor A-485 decreased STAT3 acetylation and H3K27ac. Finally, we confirmed that the P300 inhibitor A-485 inhibited the binding of STAT3 with P300, which inhibited its transcriptional activity by reducing the expression of Ccnd1 (Cyclin D1).

CONCLUSIONS

Targeting the P300 protein interaction with STAT3 may alleviate STAT3-mediated fibrotic signaling in humans and other species.

Thiouracil and triazole conjugate induces autophagy through the downregulation of Wnt/β-catenin signaling pathway in human breast cancer cells

Autophagy is vital for maintaining cellular homeostasis by breaking down unnecessary organelles and proteins within cells. Its activity varies abnormally in several diseases, including cancer, making it a potential target for therapeutic strategies. The Wnt/β-catenin signaling pathway significantly impacts cancer by stabilizing β-catenin protein and promoting the transcription of its target genes. Therefore, we aimed to identify candidate substances targeting this signaling pathway. We designed and tested a thiouracil conjugate, discovering that TTP-8 had anti-tumor effects on human breast cancer cell lines MCF-7 and MDA-MB231. Our findings showed that TTP-8 upregulated the expression of LC3 protein, a marker of autophagy in breast cancer cells, suggesting that TTP-8 might induce autophagy. Further analysis confirmed an increase in autophagy-related proteins, with consistent results obtained from flow cytometry and confocal microscopy. Interestingly, the induction of LC3 expression by TTP-8 was even more pronounced in MCF-7 and MDA-MB231 cells transfected with β-catenin siRNA. Thus, our research supports the idea that the Wnt/β-catenin signaling pathway influences the regulation of autophagy-related proteins, thereby inducing autophagy. This suggests that TTP-8 could serve as a novel agent for treating breast cancer.

The intersection of endocrine signaling and neuroimmune communication regulates neonatal nociception

Neonatal pain is a significant clinical issue but the mechanisms by which pain is produced early in life are poorly understood. Our recent work has linked the transcription factor serum response factor downstream of local growth hormone (GH) signaling to incision-related hypersensitivity in neonates. However, it remains unclear if similar mechanisms contribute to inflammatory pain in neonates. We found that local GH treatment inhibited neonatal inflammatory myalgia but appeared to do so through a unique signal transducer and activator of transcription (STAT) dependent pathway within sensory neurons. The STAT1 transcription factor appeared to regulate peripheral inflammation itself by modulation of monocyte chemoattractant protein 1 (MCP1) release from sensory neurons. Data suggests that STAT1 upregulation, downstream of GH signaling, contributes to neonatal nociception during muscle inflammation through a novel neuroimmune loop involving cytokine release from primary afferents. Results could uncover new ways to treat muscle pain and inflammation in neonates.

Nanoliposomes as nonviral vectors in cancer gene therapy

Nonviral vectors, such as liposomes, offer potential for targeted gene delivery in cancer therapy. Liposomes, composed of phospholipid vesicles, have demonstrated efficacy as nanocarriers for genetic tools, addressing the limitations of off-targeting and degradation commonly associated with traditional gene therapy approaches. Due to their biocompatibility, stability, and tunable physicochemical properties, they offer potential in overcoming the challenges associated with gene therapy, such as low transfection efficiency and poor stability in biological fluids. Despite these advancements, there remains a gap in understanding the optimal utilization of nanoliposomes for enhanced gene delivery in cancer treatment. This review delves into the present state of nanoliposomes as carriers for genetic tools in cancer therapy, sheds light on their potential to safeguard genetic payloads and facilitate cell internalization alongside the evolution of smart nanocarriers for targeted delivery. The challenges linked to their biocompatibility and the factors that restrict their effectiveness in gene delivery are also discussed along with exploring the potential of nanoliposomes in cancer gene therapy strategies by analyzing recent advancements and offering future directions.

Crosstalk between CXCL12/CXCR4/ACKR3 and the STAT3 Pathway

The reciprocal modulation between the CXCL12/CXCR4/ACKR3 axis and the STAT3 signaling pathway plays a crucial role in the progression of various diseases and neoplasms. Activation of the CXCL12/CXCR4/ACKR3 axis triggers the STAT3 pathway through multiple mechanisms, while the STAT3 pathway also regulates the expression of CXCL12. This review offers a thorough and systematic analysis of the reciprocal regulatory mechanisms between the CXCL12/CXCR4/ACKR3 signaling axis and the STAT3 signaling pathway in the context of diseases, particularly tumors. It explores the potential clinical applications in tumor treatment, highlighting possible therapeutic targets and novel strategies for targeted tumor therapy.

Brassinin alleviates cancer cachexia by suppressing diverse inflammatory mechanisms in mice

Cancer cachexia is a multifactorial condition that contributes to the death of about 20% of cancer patients. It has the potential to cause weight loss, reduction in muscle mass, and loss of fat tissue, significantly lowering the quality of life. Currently, there are no approved drugs for cancer cachexia. Here, we have explored the possible impact of brassinin (BSN) on cancer cachexia under in vitro and in vivo settings. After differentiation, C2C12 and 3T3-L1 cells were incubated with colorectal carcinoma cells conditioned media or BSN. For preclinical studies, mice were injected with HT-29 cells followed by intraperitoneal administration of BSN, and muscle and adipose tissues were evaluated by Western blotting and hematoxylin and eosin staining. BSN effectively suppressed muscle atrophy by down-regulating the levels of Muscle RING-finger protein-1 and Atrogin-1, while also increasing the expression of myosin heavy chain in cachexia-induced-C2C12 myotubes. The induction of adipogenesis by BSN prevented adipocyte atrophy in cachexia-induced 3T3-L1 adipocytes. We also noted that BSN disrupted the interaction between COX-2 and signaling transducer and activator of transcription 3 (STAT3) promoter, leading to down-regulation of STAT3 activation. Moreover, it was found that BSN inhibited weight loss in mice and demonstrated anti-cachexic effects. Overall, our observations indicate that BSN can attenuate cancer cachexia through diverse mechanisms.

Anticancer Potential of Indole Phytoalexins and Their Analogues

Indole phytoalexins, found in economically significant Cruciferae family plants, are synthesized in response to pathogen attacks or stress, serving as crucial components of plant defense mechanisms against bacterial and fungal infections. Furthermore, recent research indicates that these compounds hold promise for improving human health, particularly in terms of potential anticancer effects that have been observed in various studies. Since our last comprehensive overview in 2016 focusing on the antiproliferative effects of these substances, brassinin and camalexin have been the most extensively studied. This review analyses the multifaceted pharmacological effects of brassinin and camalexin, highlighting their anticancer potential. In this article, we also provide an overview of the antiproliferative activity of new synthetic analogs of indole phytoalexins, which were synthesized and tested at our university with the aim of enhancing efficacy compared to the parent compound.

KIAA0040 enhances glioma growth by controlling the JAK2/STAT3 signalling pathway

The role of KIAA0040 role in glioma development is not yet understood despite its connection to nervous system diseases. In this study, KIAA0040 expression levels were evaluated using qRT-PCR, WB and IHC, and functional assays were conducted to assess its impact on glioma progression, along with animal experiments. Moreover, WB was used to examine the impact of KIAA0040 on the JAK2/STAT3 signalling pathway. Our study found that KIAA0040 was increased in glioma and linked to tumour grade and poor clinical outcomes, serving as an independent prognostic factor. Functional assays showed that KIAA0040 enhances glioma growth, migration and invasion by activating the JAK2/STAT3 pathway. Of course, KIAA0040 enhances glioma growth by preventing tumour cell death and promoting cell cycle advancement. Our findings suggest that targeting KIAA0040 could be an effective treatment for glioma due to its role in promoting aggressive tumour behaviour and poor prognosis.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

Combined effects of two phytoalexins, brassinin and camalexin, on the cells of colorectal origin

Brassinin and camalexin belong to phytoalexins, plant compounds generated in the response to stress. Both compounds are known to be cytotoxic to several cancer cell lines, mainly by inducing oxidative stress and subsequent apoptosis. In the presented study, cytotoxic effects of brassinin and camalexin, individually and, for the first time, after combined exposure, on the cells of normal (CCD-Co18) and cancer (Caco-2) lines originated from colorectal tissues and their proapoptotic impact on Caco-2 cells were studied. The determined IC50 values indicate a clearly higher sensitivity of cancer cells to the tested substances, as well as a stronger cytotoxic effect of camalexin than brassinin. The synergistic effect of both phytoalexins was also demonstrated. Caspase-dependent and independent mechanisms were involved in the final effects. Both tested phytoalexins caused evident, concentration-dependent symptoms of oxidative stress in cancer cells, leading to apoptosis, but in the highest concentrations, also to necrosis. In case of camalexin, signs of pyroptosis were additionally detected.

Noncoding RNAs as regulators of STAT3 pathway in gastrointestinal cancers: Roles in cancer progression and therapeutic response

Gastrointestinal (GI) tumors (cancers of the esophagus, gastric, liver, pancreas, colon, and rectum) contribute to a large number of deaths worldwide. STAT3 is an oncogenic transcription factor that promotes the transcription of genes associated with proliferation, antiapoptosis, survival, and metastasis. STAT3 is overactivated in many human malignancies including GI tumors which accelerates tumor progression, metastasis, and drug resistance. Research in recent years demonstrated that noncoding RNAs (ncRNAs) play a major role in the regulation of many signaling pathways including the STAT3 pathway. The major types of endogenous ncRNAs that are being extensively studied in oncology are microRNAs, long noncoding RNAs, and circular RNAs. These ncRNAs can either be tumor-promoters or tumor-suppressors and each one of them imparts their activity via different mechanisms. The STAT3 pathway is also tightly modulated by ncRNAs. In this article, we have elaborated on the tumor-promoting role of STAT3 signaling in GI tumors. Subsequently, we have comprehensively discussed the oncogenic as well as tumor suppressor functions and mechanism of action of ncRNAs that are known to modulate STAT3 signaling in GI cancers.

Role of microRNAs in regulation of doxorubicin and paclitaxel responses in lung tumor cells

Lung cancer as the leading cause of cancer related mortality is always one of the main global health challenges. Despite the recent progresses in therapeutic methods, the mortality rate is still significantly high among lung cancer patients. A wide range of therapeutic methods including chemotherapy, radiotherapy, and surgery are used to treat lung cancer. Doxorubicin (DOX) and Paclitaxel (TXL) are widely used as the first-line chemotherapeutic drugs in lung cancer. However, there is a significant high percentage of DOX/TXL resistance in lung cancer patients, which leads to tumor recurrence and metastasis. Considering, the side effects of these drugs in normal tissues, it is required to clarify the molecular mechanisms of DOX/TXL resistance to introduce the efficient prognostic and therapeutic markers in lung cancer. MicroRNAs (miRNAs) have key roles in regulation of different pathophysiological processes including cell division, apoptosis, migration, and drug resistance. MiRNA deregulations are widely associated with chemo resistance in various cancers. Therefore, considering the importance of miRNAs in chemotherapy response, in the present review, we discussed the role of miRNAs in regulation of DOX/TXL response in lung cancer patients. It has been reported that miRNAs mainly induced DOX/TXL sensitivity in lung tumor cells by the regulation of signaling pathways, autophagy, transcription factors, and apoptosis. This review can be an effective step in introducing miRNAs as the non-invasive prognostic markers to predict DOX/TXL response in lung cancer patients.

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.

Resveratrol Enhances Temozolomide Efficacy in Glioblastoma Cells through Downregulated MGMT and Negative Regulators-Related STAT3 Inactivation

Chemoresistance blunts the efficacy of temozolomide (TMZ) in the treatment of glioblastoma (GBM). Elevated levels of O6-methylguanine-DNA methyltransferase (MGMT) and activation of signal transducer and of transcription 3 (STAT3) have been reported to correlate with GBM resistance to alkylator chemotherapy. Resveratrol (Res) inhibits tumor growth and improves drug chemosensitivity by targeting STAT3 signaling. Whether the combined therapy of TMZ and Res could enhance chemosensitivity against GBM cells and the underlying molecular mechanism remains to be determined. In this study, Res was found to effectively improve chemosensitivities of different GBM cells to TMZ, which was evaluated by CCK-8, flow cytometry, and cell migration assay. The combined use of Res and TMZ downregulated STAT3 activity and STAT3-regulated gene products, thus inhibited cell proliferation and migration, as well as induced apoptosis, accompanied by increased levels of its negative regulators: PIAS3, SHP1, SHP2, and SOCS3. More importantly, a combination therapy of Res and TMZ reversed TMZ resistance of LN428 cells, which could be related to decreased MGMT and STAT3 levels. Furthermore, the JAK2-specific inhibitor AG490 was used to demonstrate that a reduced MGMT level was mediated by STAT3 inactivation. Taken together, Res inhibited STAT3 signaling through modulation of PIAS3, SHP1, SHP2, and SOCS3, thereby attenuating tumor growth and increasing sensitivity to TMZ. Therefore, Res is an ideal candidate to be used in TMZ combined chemotherapy for GBM.

Mechanism of epithelial-mesenchymal transition in cancer and its regulation by natural compounds

Epithelial-mesenchymal transition (EMT) is a complex process with a primordial role in cellular transformation whereby an epithelial cell transforms and acquires a mesenchymal phenotype. This transformation plays a pivotal role in tumor progression and self-renewal, and exacerbates resistance to apoptosis and chemotherapy. EMT can be initiated and promoted by deregulated oncogenic signaling pathways, hypoxia, and cells in the tumor microenvironment, resulting in a loss-of-epithelial cell polarity, cell-cell adhesion, and enhanced invasive/migratory properties. Numerous transcriptional regulators, such as Snail, Slug, Twist, and ZEB1/ZEB2 induce EMT through the downregulation of epithelial markers and gain-of-expression of the mesenchymal markers. Additionally, signaling cascades such as Wnt/β-catenin, Notch, Sonic hedgehog, nuclear factor kappa B, receptor tyrosine kinases, PI3K/AKT/mTOR, Hippo, and transforming growth factor-β pathways regulate EMT whereas they are often deregulated in cancers leading to aberrant EMT. Furthermore, noncoding RNAs, tumor-derived exosomes, and epigenetic alterations are also involved in the modulation of EMT. Therefore, the regulation of EMT is a vital strategy to control the aggressive metastatic characteristics of tumor cells. Despite the vast amount of preclinical data on EMT in cancer progression, there is a lack of clinical translation at the therapeutic level. In this review, we have discussed thoroughly the role of the aforementioned transcription factors, noncoding RNAs (microRNAs, long noncoding RNA, circular RNA), signaling pathways, epigenetic modifications, and tumor-derived exosomes in the regulation of EMT in cancers. We have also emphasized the contribution of EMT to drug resistance and possible therapeutic interventions using plant-derived natural products, their semi-synthetic derivatives, and nano-formulations that are described as promising EMT blockers.

Graphene oxide nanoarchitectures in cancer biology: Nano-modulators of autophagy and apoptosis

Nanotechnology is a growing field, with many potential biomedical applications of nanomedicine for the treatment of different diseases, particularly cancer, on the horizon. Graphene oxide (GO) nanoparticles can act as carbon-based nanocarriers with advantages such as a large surface area, good mechanical strength, and the capacity for surface modification. These nanostructures have been extensively used in cancer therapy for drug and gene delivery, photothermal therapy, overcoming chemotherapy resistance, and for imaging procedures. In the current review, we focus on the biological functions of GO nanoparticles as regulators of apoptosis and autophagy, the two major forms of programmed cell death. GO nanoparticles can either induce or inhibit autophagy in cancer cells, depending on the conditions. By stimulating autophagy, GO nanocarriers can promote the sensitivity of cancer cells to chemotherapy. However, by impairing autophagy flux, GO nanoparticles can reduce cell survival and enhance inflammation. Similarly, GO nanomaterials can increase ROS production and induce DNA damage, thereby sensitizing cancer cells to apoptosis. In vitro and in vivo experiments have investigated whether GO nanomaterials show any toxicity in major body organs, such as the brain, liver, spleen, and heart. Molecular pathways, such as ATG, MAPK, JNK, and Akt, can be regulated by GO nanomaterials, leading to effects on autophagy and apoptosis. These topics are discussed in this review to shed some lights towards the biomedical potential of GO nanoparticles and their biocompatibility, paving the way for their future application in clinical trials.

The Journey of Resveratrol from Vineyards to Clinics

With rising technological advancements, several factors influence the lifestyle of people and stimulate chronic inflammation that severely affects the human body. Chronic inflammation leads to a broad range of physical and pathophysiological distress. For many years, non-steroidal drugs and corticosteroids were most frequently used in treating inflammation and related ailments. However, long-term usage of these drugs aggravates the conditions of chronic diseases and is presented with morbid side effects, especially in old age. Hence, the quest for safe and less toxic anti-inflammatory compounds of high therapeutic potential with least adverse side effects has shifted researchers' attention to ancient medicinal system. Resveratrol (RSV) - 3,4,5^' trihydroxystilbene is one such naturally available polyphenolic stilbene derivative obtained from various plant sources. For over 2000 years, these plants have been used in Asian medicinal system for curing inflammation-associated disorders. There is a wealth of in vitro, in vivo and clinical evidence that shows RSV could induce anti-aging health benefits including, anti-cancer, anti-inflammatory, anti-oxidant, phytoesterogenic, and cardio protective properties. However, the issue of rapid elimination of RSV through the metabolic system and its low bio-availability is of paramount importance which is being studied extensively. Therefore, in this article, we scientifically reviewed the molecular targets, biological activities, beneficial and contradicting effects of RSV as evinced by clinical studies for the prevention and treatment of inflammation-mediated chronic disorders.

Identifying molecular targets of Aspiletrein-derived steroidal saponins in lung cancer using network pharmacology and molecular docking-based assessments

Lung cancer is one of the leading cancers and causes of cancer-related deaths worldwide. Due to its high prevalence and mortality rate, its clinical management remains a significant challenge. Previously, the in vitro anticancer activity of Aspiletrein A, a steroid and a saponin from Aspidistra letreae, against non-small cell lung cancer (NSCLC) cells was reported. However, the anticancer molecular mechanism of other Aspiletreins from A. letreae remains unknown. Using in silico network pharmacology approaches, the targets of Aspiletreins were predicted using the Swiss Target Prediction database. In addition, key mediators in NSCLC were obtained from the Genetic databases. The compound-target interacting networks were constructed using the STRING database and Cytoscape, uncovering potential targets, including STAT3, VEGFA, HSP90AA1, FGF2, and IL2. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis demonstrated that several pathways were highly relevant to cancer pathogenesis. Additionally, molecular docking and molecular dynamic analyses revealed the interaction between key identified targets and Aspiletreins, including hydrogen bonding and Van der Waals interaction. This study provides potential targets of Aspiletreins in NSCLC, and its approach of integrating network pharmacology, bioinformatics, and molecular docking is a powerful tool for investigating the mechanism of new drug targets on a specific disease.

Advances in the role of STAT3 in macrophage polarization

The physiological processes of cell growth, proliferation, differentiation, and apoptosis are closely related to STAT3, and it has been demonstrated that aberrant STAT3 expression has an impact on the onset and progression of a number of inflammatory immunological disorders, fibrotic diseases, and malignancies. In order to produce the necessary biological effects, macrophages (M0) can be polarized into pro-inflammatory (M1) and anti-inflammatory (M2) types in response to various microenvironmental stimuli. STAT3 signaling is involved in macrophage polarization, and the research of the effect of STAT3 on macrophage polarization has gained attention in recent years. In order to provide references for the treatment and investigation of disorders related to macrophage polarization, this review compiles the pertinent signaling pathways associated with STAT3 and macrophage polarization from many fundamental studies.

Role of STAT3 and NRF2 in Tumors: Potential Targets for Antitumor Therapy

Signal transducer and activator of transcription 3 (STAT3) and nuclear factor erythroid-derived 2-like 2 (NRF2, also known as NFE2L2), are two of the most complicated transcription regulators, which participate in a variety of physiological processes. Numerous studies have shown that they are overactivated in multiple types of tumors. Interestingly, STAT3 and NRF2 can also interact with each other to regulate tumor progression. Hence, these two important transcription factors are considered key targets for developing a new class of antitumor drugs. This review summarizes the pivotal roles of the two transcription regulators and their interactions in the tumor microenvironment to identify potential antitumor drug targets and, ultimately, improve patients' health and survival.

Modulation of diverse oncogenic signaling pathways by oroxylin A: An important strategy for both cancer prevention and treatment

BACKGROUND

Regardless of major advances in diagnosis, prevention and treatment strategies, cancer is still a foreboding cause due to factors like chemoresistance, radioresistance, adverse side effects and cancer recurrence. Therefore, continuous development of unconventional approaches is a prerequisite to overcome foregoing glitches. Natural products have found their way into treatment of serious health conditions, including cancer since ancient times. The compound oroxylin A (OA) is one among those with enormous potential against different malignancies. It is a flavonoid obtained from the several plants such as Oroxylum indicum, Scutellaria baicalensis and S. lateriflora, Anchietea pyrifolia, and Aster himalaicus.

PURPOSE

The main purpose of this study is to comprehensively elucidate the anticancerous effects of OA against various malignancies and unravel their chemosensitization and radiosensitization potential. Pharmacokinetic and pharmacodynamic studies of OA have also been investigated.

METHOD

The literature on antineoplastic effects of OA was searched in PubMed and Scopus, including in vitro and in vivo studies and is summarized based on a systematic review protocol prepared according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The term "oroxylin A" was used in combination with "cancer" and all the title, abstracts and keywords appeared were considered.

RESULTS

In Scopus, a total of 157 articles appeared out of which 103 articles that did not meet the eligibility criteria were eliminated and 54 were critically evaluated. In PubMed, from the 85 results obtained, 26 articles were eliminated and 59 were included in the preparation of this review. Mounting number of studies have illustrated the anticancer effects of OA, and its mechanism of action.

CONCLUSION

OA is a promising natural flavonoid possessing wide range of pleiotropic properties and is a potential anticancer agent. It has a great potential in the treatment of multiple cancers including brain, breast, cervical, colon, esophageal, gall bladder, gastric, hematological, liver, lung, oral, ovarian, pancreatic and skin. However, lack of pharmacokinetic studies, toxicity assessments, and dose standardization studies and adverse effects limit the optimization of this compound as a therapeutic agent.

Brassinin Promotes the Degradation of Tie2 and FGFR1 in Endothelial Cells and Inhibits Triple-Negative Breast Cancer Angiogenesis

Simple Summary

Brassinin is a natural compound enriched in several commonly consumed vegetables, such as broccoli and cabbages. It shows potent anti-cancer activity against several cancers. However, its effects on triple-negative breast cancer (TNBC), an aggressive subtype with limited treatment options, remain elusive so far. Therefore, we investigated the effects of brassinin on TNBC angiogenesis and growth. Our results demonstrate that brassinin inhibits TNBC growth preferentially through inhibiting the angiogenic activity of endothelial cells (ECs). Additional in-vitro analyses revealed that this effect may be mediated by brassinin-stimulated degradation of two pivotal angiogenesis-related receptors in ECs: Tie2 and fibroblast growth factor receptor 1. These findings provide novel insights into the cellular and molecular mechanisms underlying the anti-cancer activity of brassinin and indicate that this phytochemical may be a promising lead compound or drug candidate for TNBC treatment.

Abstract

Brassinin, a phytoalexin derived from cruciferous vegetables, has been reported to exhibit anti-cancer activity in multiple cancer types. However, its effects on triple-negative breast cancer (TNBC) development and the underlying mechanisms have not been elucidated so far. In this study, we demonstrated in vitro that brassinin preferentially reduces the viability of endothelial cells (ECs) when compared to other cell types of the tumor microenvironment, including TNBC cells, pericytes, and fibroblasts. Moreover, brassinin at non-cytotoxic doses significantly suppressed the proliferation, migration, tube formation, and spheroid sprouting of ECs. It also efficiently inhibited angiogenesis in an ex-vivo aortic ring assay and an in-vivo Matrigel plug assay. Daily intraperitoneal injection of brassinin significantly reduced tumor size, microvessel density, as well as the perfusion of tumor microvessels in a dorsal skinfold chamber model of TNBC. Mechanistic analyses showed that brassinin selectively stimulates the degradation of Tie2 and fibroblast growth factor receptor 1 in ECs, leading to the down-regulation of the AKT and extracellular signal-regulated kinase pathways. These findings demonstrate a preferential and potent anti-angiogenic activity of brassinin, which may be the main mechanism of its anti-tumor action. Accordingly, this phytochemical represents a promising candidate for the future anti-angiogenic treatment of TNBC.

STAT3-EMT axis in tumors: modulation of cancer metastasis, stemness and therapy response

Epithelial-to-mesenchymal transition (EMT) mechanism is responsible for metastasis of tumor cells and their spread to various organs and tissues of body, providing undesirable prognosis. In addition to migration, EMT increases stemness and mediates therapy resistance. Hence, pathways involved in EMT regulation should be highlighted. STAT3 is an oncogenic pathway that can elevate growth rate and migratory ability of cancer cells and induce drug resistance. The inhibition of STAT3 signaling impairs cancer progression and promotes chemotherapy-mediated cell death. Present review focuses on STAT3 and EMT interaction in modulating cancer migration. First of all, STAT3 is an upstream mediator of EMT and is able to induce EMT-mediated metastasis in brain tumors, thoracic cancers and gastrointestinal cancers. Therefore, STAT3 inhibition significantly suppresses cancer metastasis and improves prognosis of patients. EMT regulators such as ZEB1/2 proteins, TGF-β, Twist, Snail and Slug are affected by STAT3 signaling to stimulate cancer migration and invasion. Different molecular pathways such as miRNAs, lncRNAs and circRNAs modulate STAT3/EMT axis. Furthermore, we discuss how STAT3 and EMT interaction affects therapy response of cancer cells. Finally, we demonstrate targeting STAT3/EMT axis by anti-tumor agents and clinical application of this axis for improving patient prognosis.

STAT3 pathway in cancers: Past, present, and future

Signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, discovered in the cytoplasm of almost all types of mammalian cells, plays a significant role in biological functions. The duration of STAT3 activation in normal tissues is a transient event and is strictly regulated. However, in cancer tissues, STAT3 is activated in an aberrant manner and is induced by certain cytokines. The continuous activation of STAT3 regulates the expression of downstream proteins associated with the formation, progression, and metastasis of cancers. Thus, elucidating the mechanisms of STAT3 regulation and designing inhibitors targeting the STAT3 pathway are considered promising strategies for cancer treatment. This review aims to introduce the history, research advances, and prospects concerning the STAT3 pathway in cancer. We review the mechanisms of STAT3 pathway regulation and the consequent cancer hallmarks associated with tumor biology that are induced by the STAT3 pathway. Moreover, we summarize the emerging development of inhibitors that target the STAT3 pathway and novel drug delivery systems for delivering these inhibitors. The barriers against targeting the STAT3 pathway, the focus of future research on promising targets in the STAT3 pathway, and our perspective on the overall utility of STAT3 pathway inhibitors in cancer treatment are also discussed.

Fangchinoline targets epithelial-mesenchymal transition process by modulating activation of multiple cell-signaling pathways

Epithelial-mesenchymal transition (EMT) is a key process, which can promote the transition of tumor cells into other organs by weakening the cell-cell junctions. Tumor cell invasion and metastasis arising because of EMT can determine the prognosis of cancer. EMT can be induced by several growth factors including transforming growth factor-β (TGF-β), which can exert their effects by affecting several cell-signaling pathways. Fangchinoline (FCN), a kind of bisbenzylisoquinoline, belongs to the family Menispermaceae. FCN can display substantial antitumor effects against various malignant cell lines but its possible impact on EMT has not been explored. We examined the potential impact of FCN in affecting the activation of EMT in human colon cancer cells. We evaluated the influence of FCN on EMT in colon cancer cells by using Western blot analysis and reverse transcription-polymerase chain reaction assays. The cellular invasion and migration were observed by Boyden chamber and wound healing assays. Thereafter, the effect of the drug on proliferation and invasion was also evaluated by real-time cell analysis. FCN suppressed the levels of TGF-β-induced mesenchymal markers, such as fibronectin, vimentin, MMP-9, MMP-2, N-cadherin, Twist, and Snail. However, FCN markedly enhanced the expression of epithelial markers such as occludin and E-cadherin. These results imply that FCN can potentially inhibit tumor metastasis through abrogating EMT. In addition, FCN downregulated c-Met/PI3K/Akt/mTOR and Wnt/β-catenin cell signaling pathways and mitigated tumor migration as well as invasion. Overall, our study suggests a potential novel role of FCN as an antimetastatic agent against human colon cancer cells.

Leelamine Exerts Antineoplastic Effects in Association with Modulating Mitogen‑Activated Protein Kinase Signaling Cascade

Mitogen‑activated protein kinase (MAPK) pathway is a prominent signaling cascade that modulates cell proliferation, apoptosis, stress response, drug resistance, immune response, and cell motility. Activation of MAPK by various small molecules/natural compounds has been demonstrated to induce apoptosis in cancer cells. Herein, the effect of leelamine (LEE, a triterpene derived from bark of pine trees) on the activation of MAPK in hepatocellular carcinoma (HCC) and breast cancer (BC) cells was investigated. LEE induced potent cytotoxicity of HCC (HepG2 and HCCLM3) and BC (MDA-MB-231 and MCF7) cells over normal counterparts (MCF10A). LEE significantly enhanced the phosphorylation of p38 and JNK MAPKs in a dose-dependent fashion and it did not affect the phosphorylation of ERK in HCC and BC cells. The apoptosis-driving effect of LEE was further demonstrated by cleavage of procaspase-3/Bid and suppression of prosurvival proteins (Bcl-xL and XIAP). Furthermore, LEE also reduced the SDF1-induced-migration and -invasion of HCC and BC cells. Taken together, the data demonstrated that LEE promotes apoptosis and induces an anti-motility effect by activating p38 and JNK MAPKs in HCC and BC cells.

Brassinin Enhances Apoptosis in Hepatic Carcinoma by Inducing Reactive Oxygen Species Production and Suppressing the JAK2/STAT3 Pathway

Plants from the family Brassicaceae produce brassinin (BSN), which is an essential indole phytoalexin. BSN can kill certain types of cancer cells. Using hepatocarcinoma (HCC) cells, we examined the molecular mechanisms of BSN. We found that HCC cell growth was suppressed and apoptosis was induced by BSN via the downregulation of the JAK/STAT3 pathway. The cytoplasmic latent transcription factor STAT3, belonging to the STAT family, acted as both a signal transducer and an activator and was linked to tumor progression and decreased survival. BSN incubation caused HCC cells to produce reactive oxygen species (ROS). By activating caspase-9/-3 and PARP cleavage, Bcl-2 was reduced, and apoptosis was increased. BSN inhibited constitutive STAT3, JAK2, and Src phosphorylation. The JAK/STAT signaling cascade was confirmed by siRNA silencing STAT3 in HCC cells. BSN also suppressed apoptosis by Z-Val-Ala-Asp-Fluoromethylketone (Z-VAD-FMK), an apoptotic inhibitor. N-acetylcysteine (NAC) inhibited the production of ROS and diminished BSN-induced apoptosis. Our findings suggested that BSN has potential as a treatment for cancer.

Targeting autophagy in prostate cancer: preclinical and clinical evidence for therapeutic response

Prostate cancer is a leading cause of death worldwide and new estimates revealed prostate cancer as the leading cause of death in men in 2021. Therefore, new strategies are pertinent in the treatment of this malignant disease. Macroautophagy/autophagy is a “self-degradation” mechanism capable of facilitating the turnover of long-lived and toxic macromolecules and organelles. Recently, attention has been drawn towards the role of autophagy in cancer and how its modulation provides effective cancer therapy. In the present review, we provide a mechanistic discussion of autophagy in prostate cancer. Autophagy can promote/inhibit proliferation and survival of prostate cancer cells. Besides, metastasis of prostate cancer cells is affected (via induction and inhibition) by autophagy. Autophagy can affect the response of prostate cancer cells to therapy such as chemotherapy and radiotherapy, given the close association between autophagy and apoptosis. Increasing evidence has demonstrated that upstream mediators such as AMPK, non-coding RNAs, KLF5, MTOR and others regulate autophagy in prostate cancer. Anti-tumor compounds, for instance phytochemicals, dually inhibit or induce autophagy in prostate cancer therapy. For improving prostate cancer therapy, nanotherapeutics such as chitosan nanoparticles have been developed. With respect to the context-dependent role of autophagy in prostate cancer, genetic tools such as siRNA and CRISPR-Cas9 can be utilized for targeting autophagic genes. Finally, these findings can be translated into preclinical and clinical studies to improve survival and prognosis of prostate cancer patients.

• Prostate cancer is among the leading causes of death in men where targeting autophagy is of importance in treatment;

• Autophagy governs proliferation and metastasis capacity of prostate cancer cells;

• Autophagy modulation is of interest in improving the therapeutic response of prostate cancer cells;

• Molecular pathways, especially involving non-coding RNAs, regulate autophagy in prostate cancer;

• Autophagy possesses both diagnostic and prognostic roles in prostate cancer, with promises for clinical application.

Corilagin exhibits differential anticancer effects through the modulation of STAT3/5 and MAPKs in human gastric cancer cells

Corilagin (CLG) is a hydrolyzable tannin and possesses various pharmacological activities. Here, we investigated the impact of CLG as an anti-tumor agent against human gastric tumor cells. We observed that CLG could cause negative regulation of JAKs-Src-STAT3/5 signaling axis in SNU-1 cells, but did not affect these pathways in SNU-16 cells. Interestingly, CLG promoted the induction of mitogen-activated protein kinases (MAPKs) signaling pathways in only SNU-16 cells, but not in the SNU-1 cells. CLG exhibited apoptotic effects that caused an increased accumulation of the cells in sub-G1 phase and caspase-3 activation in both SNU-1 and SNU-16 cell lines. We also noticed that CLG and docetaxel co-treatment could exhibit significantly enhanced apoptotic effects against SNU-1 cells. Moreover, the combinations treatment of CLG and docetaxel markedly inhibited cell growth, phosphorylation of JAK-Src-STAT3 and induced substantial apoptosis. Additionally, pharmacological inhibition of JNK, p38, and ERK substantially blocked CLG-induced activation of MAPKs, cell viability, and apoptosis, thereby implicating the pivotal role of MAPKs in the observed anti-cancer effects of CLG. Taken together, our data suggest that CLG could effectively block constitutive STAT3/5 activation in SNU-1 cells but induce sustained MAPKs activation in SNU-16 cells.

Sesquiterpene Lactones Attenuate Paclitaxel Resistance Via Inhibiting MALAT1/STAT3/ FUT4 Axis and P-Glycoprotein Transporters in Lung Cancer Cells

Paclitaxel resistance is a challenging factor in chemotherapy resulting in poor prognosis and cancer recurrence. Signal transducer and activator of transcription factor 3 (STAT3), a key transcription factor, performs a critical role in cancer development, cell survival and chemoresistance, while its inactivation overwhelms drug resistance in numerous cancer types including lung cancer. Additionally, the fucosyltransferase 4 (FUT4) is a crucial enzyme in post-translational modification of cell-surface proteins involved in various pathological conditions such as tumor multidrug resistance (MDR). The P-glycoprotein (P-GP) is the well-known ABC transporter member that imparts drug resistance in different cancer types, most notably paclitaxel resistance in lung cancer cells. LncRNA-MALAT1 exerts a functional role in the cancer development as well as the drug resistance and is linked with STAT3 activation and activity of FUT4. Moreover, STAT3-mediated induction of P-GP is well-documented. Natural compounds of Sesquiterpene Lactone (SL) family are well-known for their anticancer properties with particular emphasis over STAT3 inhibitory capabilities. In this study, we explored the positive correlation of MALAT1 with STAT3 and FUT4 activity in paclitaxel resistant A549 (A549/T) lung cancer cells. Additionally, we investigated the anticancer activity of two well-known members of SLs, alantolactone (ALT) and Brevilin A (Brv-A), in A549/T lung cancer cells. ALT and Brv-A induced apoptosis in A549/T cells. Furthermore, these two natural SLs suppressed MALAT1 expression, STAT3 activation, and FUT4 and P-GP expression which are the hallmarks for paclitaxel resistance in A549 lung cancer cells. The inhibition of MALAT1 enhanced the competence of these SLs members significantly, which accounted for the growth inhibition as well as anti-migratory and anti-invasive effects of ALT and Brv-A. These findings suggest SLs to be the promising agents for overcoming paclitaxel resistance in A549 lung cancer cells.

Transforming growth factor-beta (TGF-β) in prostate cancer: A dual function mediator?

Transforming growth factor-beta (TGF-β) is a member of a family of secreted cytokines with vital biological functions in cells. The abnormal expression of TGF-β signaling is a common finding in pathological conditions, particularly cancer. Prostate cancer (PCa) is one of the leading causes of death among men. Several genetic and epigenetic alterations can result in PCa development, and govern its progression. The present review attempts to shed some light on the role of TGF-β signaling in PCa. TGF-β signaling can either stimulate or inhibit proliferation and viability of PCa cells, depending on the context. The metastasis of PCa cells is increased by TGF-β signaling via induction of EMT and MMPs. Furthermore, TGF-β signaling can induce drug resistance of PCa cells, and can lead to immune evasion via reducing the anti-tumor activity of cytotoxic T cells and stimulating regulatory T cells. Upstream mediators such as microRNAs and lncRNAs, can regulate TGF-β signaling in PCa. Furthermore, some pharmacological compounds such as thymoquinone and valproic acid can suppress TGF-β signaling for PCa therapy. TGF-β over-expression is associated with poor prognosis in PCa patients. Furthermore, TGF-β up-regulation before prostatectomy is associated with recurrence of PCa. Overall, current review discusses role of TGF-β signaling in proliferation, metastasis and therapy response of PCa cells and in order to improve knowledge towards its regulation, upstream mediators of TGF-β such as non-coding RNAs are described. Finally, TGF-β regulation and its clinical application are discussed.

Fangchinoline diminishes STAT3 activation by stimulating oxidative stress and targeting SHP-1 protein in multiple myeloma model

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Aberrant STAT3 activation can promote neoplastic transformation by affecting cellular proliferation, invasion, metastasis, angiogenesis, and anti-apoptosis induction.

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Fangchinoline abrogated protein expression levels of STAT3 and upstream signals (JAK1/2 and Src) in different tumor cells.

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Fangchinoline inhibited the levels of various tumorigenic markers and promoted marked apoptosis through degradation of PARP and caspase-3.

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Fangchinoline attenuated the level of STAT3 and upstream signals and suppressed the level of anti- apoptotic proteins in xenograft mice model.

Introduction

The development of cancer generally occurs as a result of various deregulated molecular mechanisms affecting the genes that can control normal cellular growth. Signal transducer and activator of transcription 3 (STAT3) pathway, once aberrantly activated can promote carcinogenesis by regulating the transcription of a number of oncogenic genes.

Objectives

Here, we evaluated the impact of fangchinoline (FCN) to attenuate tumor growth and survival through modulation of oncogenic STAT3 signaling pathway using diverse tumor cell lines and a xenograft mouse model.

Methods

To evaluate the action of FCN on STAT3 cascade, protein levels were analyzed by Western blot analysis and electrophoretic mobility shift assay (EMSA). Translocation of STAT3 was detected by immunocytochemistry. Thereafter, FCN-induced ROS was measured by GSH/GSSG assay and H2DCF-DA. FCN-induced apoptosis was analyzed using Western blot analysis and flow cytometry for various assays. Finally, anti-cancer effects of FCN in vivo was evaluated in a myeloma model.

Results

We noted that FCN abrogated protein expression levels of STAT3 and upstream signals (JAK1/2 and Src). In addition, FCN also attenuated DNA binding ability of STAT3 and its translocation into the nucleus. It altered the levels of upstream signaling proteins, increased SHP-1 levels, and induced substantial apoptosis in U266 cells. FCN also promoted an increased production of reactive oxygen species (ROS) and altered GSSG/GSH ratio in tumor cells. Moreover, FCN effectively abrogated tumor progression and STAT3 activation in a preclinical myeloma model.

Conclusion

Overall, this study suggests that FCN may have a tremendous potential to alter abnormal STAT3 activation and induce cell death in malignant cells along with causing the suppression of pathogenesis and growth of cancer through a pro-oxidant dependent molecular mechanism.

3-Formylchromone Counteracts STAT3 Signaling Pathway by Elevating SHP-2 Expression in Hepatocellular Carcinoma

Simple Summary

STAT3 acts as a potential tumor-promoting transcription factor that gets aberrantly activated in several types of human cancers and plays a crucial role in tumor progression and metastasis. STAT3 expression has been correlated with a dismal prognosis and poor survival. In this study, we have demonstrated that 3-formylchromone inhibits the STAT3 signaling in HCC cells by modulating SHP-2 expression. It also effectively diminished the tumor growth and subsequent reduction in metastasis in the HCC mouse model without exhibiting any major side effects.

Abstract

Hepatocellular carcinoma (HCC) is one of the leading cancers that contribute to a large number of deaths throughout the globe. The signal transducer and activator of transcription 3 (STAT3) is a tumorigenic protein that is overactivated in several human malignancies including HCC. In the present report, the effect of 3-formylchromone (3FC) on the STAT3 signaling pathway in the HCC model was investigated. 3FC downregulated the constitutive phosphorylation of STAT3 and non-receptor tyrosine kinases such as JAK1 and JAK2. It also suppressed the transportation of STAT3 to the nucleus and reduced its DNA-binding ability. Pervanadate treatment overrode the 3FC-triggered STAT3 inhibition, and the profiling of cellular phosphatase expression revealed an increase in SHP-2 levels upon 3FC treatment. The siRNA-driven deletion of SHP-2 led to reinstate STAT3 activation. 3FC downmodulated the levels of various oncogenic proteins and decreased CXCL12-driven cell migration and invasion. Interestingly, 3FC did not exhibit any substantial toxicity, whereas it significantly regressed tumor growth in an orthotopic HCC mouse model and abrogated lung metastasis. Overall, 3FC can function as a potent agent that can display antitumor activity by targeting STAT3 signaling in HCC models.

Abrogation of STAT3 activation cascade by Ginkgolide C mitigates tumourigenesis in lung cancer preclinical model

OBJECTIVES

Ginkgolide C (GGC) isolated from Ginkgo biloba (Ginkgoaceae) leaf can demonstrate pleiotropic pharmacological actions. However, its anti-oncogenic impact in non-small cell lung cancer (NSCLC) model has not been reconnoitered. As signal transducer and activator of transcription 3 (STAT3) cascade can promote tumour growth and survival, we contemplated that GGC may interrupt this signalling cascade to expend its anti-cancer actions in NSCLC.

METHODS

The effect of GGC on STAT3 activation, associated protein kinases, STAT3-regulated gene products, cellular proliferation and apoptosis was examined. The in-vivo effect of GGC on the growth of human NSCLC xenograft tumours in athymic nu/nu female mice was also investigated.

KEY FINDINGS

GGC attenuated the phosphorylation of STAT3 and STAT3 upstream kinases effectively. Exposure to pervanadate modulated GGC-induced down-regulation of STAT3 activation and promoted an elevation in the level of PTPε protein. Indeed, silencing of the PTPε gene reversed the GGC-promoted abrogation of STAT3 activation and apoptosis. Moreover, GGC exposure significantly reduced NSCLC tumour growth without demonstrating significant adverse effects via decreasing levels of p-STAT3 in mice tissues.

CONCLUSIONS

Overall, the findings support that GGC may exhibit anti-neoplastic actions by mitigation of STAT3 signalling cascade in NSCLC.

Potential function of oxymatrine as a novel suppressor of epithelial-to-mesenchymal transition in lung tumor cells

AIMS

Tumor cells metastasis as well as proliferation are important factors that can substantially determines the prognosis of cancer. In particular, epithelial-mesenchymal transition (EMT) is key phenomena which can cause tumor cell transition into other organs by promoting the disruption of the cell-cell junctions. Because oxymatrine (OMT) have been reported to attenuate the tumor growth, we investigated whether OMT can down-regulate EMT process in tumor cells. We also focused on transforming growth factor-β (TGF-β)-induced EMT process because EMT process can be significantly induced by this growth factor.

MAIN METHODS

The cell viability was measured by MTT and real time cell analysis (RTCA) assay. The expression levels of various proteins involved in the regulation of EMT and Akt/mTOR/PI3K signaling pathway were evaluated by Western blot analysis. mRNA levels of several important EMT markers were analyzed by reverse transcription polymerase chain reaction (RT-PCR). The effects of OMT on the cellular invasion and migration were evaluated by RTCA, wound healing assay, and boyden chamber assays.

KEY FINDINGS

OMT suppressed the expression of both constitutive and TGF-β-induced mesenchymal markers, such as fibronectin, vimentin, MMP-9, MMP-2, N-cadherin, Twist, and Snail, but induced the levels of epithelial markers. Moreover, OMT down-regulated oncogenic PI3K/Akt/mTOR pathways which lead to a significant attenuation of invasive and migratory potential of lung cancer cells.

SIGNIFICANCE

Overall, our study established a novel anti-metastatic role of OMT against human lung cancer cells.

Tris(dibenzylideneacetone)dipalladium(0) (Tris DBA) Abrogates Tumor Progression in Hepatocellular Carcinoma and Multiple Myeloma Preclinical Models by Regulating the STAT3 Signaling Pathway

Simple Summary

STAT3 is a major oncogenic transcription factor that is constitutively activated in many types of human cancers, including hepatocellular carcinoma (HCC) and multiple myeloma (MM). Many STAT3 inhibitors have gained momentum in clinical trials towards the treatment of various cancers. In the present study, we have investigated the STAT3 inhibitory efficacy of Tris DBA, a palladium-based compound, in HCC and MM cancer cells and preclinical cancer models. Tris(dibenzylideneacetone)dipalladium(0) (Tris DBA) abrogated the STAT3 signaling pathway in both models by elevating the expression of SHP2. Functionally, Tris DBA inhibited cell proliferation, migration, invasion, and regressed tumor metastasis. Although many studies propose Tris DBA as a modulator of MAPK, Akt, phospho-S6 kinase, and N-myristoyltransferase-1, we have comprehensively demonstrated for the first time that Tris DBA is an inhibitor of STAT3 signaling in preclinical cancer models. These results support the consideration of Tris DBA in clinical trials in translational relevance.

Abstract

STAT3 is an oncogenic transcription factor that controls the expression of genes associated with oncogenesis and malignant progression. Persistent activation of STAT3 is observed in human malignancies, including hepatocellular carcinoma (HCC) and multiple myeloma (MM). Here, we have investigated the action of Tris(dibenzylideneacetone) dipalladium 0 (Tris DBA) on STAT3 signaling in HCC and MM cells. Tris DBA decreased cell viability, increased apoptosis, and inhibited IL-6 induced/constitutive activation of STAT3, JAK1, JAK2, and Src in HCC and MM cells. Tris DBA downmodulated the nuclear translocation of STAT3 and reduced its DNA binding ability. It upregulated the expression of SHP2 (protein and mRNA) to induce STAT3 dephosphorylation, and the inhibition of SHP2 reversed this effect. Tris DBA downregulated the expression of STAT3-driven genes, suppressed cell migration/invasion. Tris DBA significantly inhibited tumor growth in xenograft MM and orthotopic HCC preclinical mice models with a reduction in the expression of various prosurvival biomarkers in MM tumor tissues without displaying significant toxicity. Overall, Tris DBA functions as a good inhibitor of STAT3 signaling in preclinical HCC and MM models.

Paclitaxel: Application in Modern Oncology and Nanomedicine-Based Cancer Therapy

Paclitaxel is a broad-spectrum anticancer compound, which was derived mainly from a medicinal plant, in particular, from the bark of the yew tree Taxus brevifolia Nutt. It is a representative of a class of diterpene taxanes, which are nowadays used as the most common chemotherapeutic agent against many forms of cancer. It possesses scientifically proven anticancer activity against, e.g., ovarian, lung, and breast cancers. The application of this compound is difficult because of limited solubility, recrystalization upon dilution, and cosolvent-induced toxicity. In these cases, nanotechnology and nanoparticles provide certain advantages such as increased drug half-life, lowered toxicity, and specific and selective delivery over free drugs. Nanodrugs possess the capability to buildup in the tissue which might be linked to enhanced permeability and retention as well as enhanced antitumour influence possessing minimal toxicity in normal tissues. This article presents information about paclitaxel, its chemical structure, formulations, mechanism of action, and toxicity. Attention is drawn on nanotechnology, the usefulness of nanoparticles containing paclitaxel, its opportunities, and also future perspective. This review article is aimed at summarizing the current state of continuous pharmaceutical development and employment of nanotechnology in the enhancement of the pharmacokinetic and pharmacodynamic features of paclitaxel as a chemotherapeutic agent.

Pyrimidine-2,4-dione targets STAT3 signaling pathway to induce cytotoxicity in hepatocellular carcinoma cells

Signal transducer and activator of transcription 3 (STAT3) is a tumorigenic transcription factor that is persistently activated in various human cancers including hepatocellular carcinoma (HCC). Therefore, STAT3 is considered as a prominent target to counteract the uncontrolled proliferation of cancer cells. In the present report, pyrimidine-2,4-diones (N-methyluracil derivatives) (MNK1-MNK14) were synthesized in an ionic liquid (BMIm PF₆) medium employing a ligand-free Suzuki-Miyaura cross-coupling process. Among the 14 derivatives, compound MNK8 showed good cytotoxicity towards both the tested cell lines and did not display a toxic effect against normal hepatocytes (LO2). MNK8 significantly increased the Sub-G1 cell count in both cell lines and the cytotoxic effect of MNK8 was found to be mediated through the suppression of constitutive phosphorylation of STAT3^Y705. It also decreased the DNA interaction ability of nuclear STAT3 in HCC cells. MNK8 downregulated the levels of apoptosis-related proteins (such as Bcl-2, cyclin D1, survivin) and increased cleaved caspase-3 inferring the apoptogenic effect of MNK8. It also reduced the CXCL12-triggered cell migration and invasion in in vitro assay systems. Overall, MNK8 has been demonstrated as a new inhibitor of STAT3 signaling cascade in HCC cells.

Crocetin imparts antiproliferative activity via inhibiting STAT3 signaling in hepatocellular carcinoma

STAT3 is a key oncogenic transcription factor, often overactivated in several human cancers including hepatocellular carcinoma (HCC). STAT3 modulates the expression of genes that are connected with cell proliferation, antiapoptosis, metastasis, angiogenesis, and immune evasion in tumor cells. In this study, we investigated the effect of crocetin on the growth of HCC cells and dissected its underlying molecular mechanism in imparting a cytotoxic effect. Crocetin suppressed proliferation, promoted apoptosis, and counteracted the invasive capacity of HCC cells. Besides, crocetin downregulated the constitutive/inducible STAT3 activation (STAT3^Y705 ), nuclear accumulation of STAT3 along with suppression of its DNA binding activity in HCC cells with no effect on STAT5 activation. Crocetin suppressed the activity of upstream kinases such as Src, JAK1, and JAK2. Sodium pervanadate treatment terminated the crocetin-propelled STAT3 inhibition suggesting the involvement of tyrosine phosphatases. Crocetin increased the expression of SHP-1 and siRNA-mediated SHP-1 silencing resulted in the negation of crocetin-driven STAT3 inhibition. Further investigation revealed that crocetin treatment inhibited the expression of STAT3 regulated genes (Bcl-2, Bcl-xL, cyclin D1, survivin, VEGF, COX-2, and MMP-9). Taken together, this report presents crocetin as a novel abrogator of the STAT3 pathway in HCC cell lines.

Current clinical developments in curcumin-based therapeutics for cancer and chronic diseases

The last decade has seen an unprecedented rise in the prevalence of chronic diseases worldwide. Different mono-targeted approaches have been devised to treat these multigenic diseases, still most of them suffer from limited success due to the off-target debilitating side effects and their inability to target multiple pathways. Hence a safe, efficacious, and multi-targeted approach is the need for the hour to circumvent these challenging chronic diseases. Curcumin, a natural compound extracted from the rhizomes of Curcuma longa, has been under intense scrutiny for its wide medicinal and biological properties. Curcumin is known to manifest antibacterial, antiinflammatory, antioxidant, antifungal, antineoplastic, antifungal, and proapoptotic effects. A plethora of literature has already established the immense promise of curcuminoids in the treatment and clinical management of various chronic diseases like cancer, cardiovascular, metabolic, neurological, inflammatory, and infectious diseases. To date, more than 230 clinical trials have opened investigations to understand the pharmacological aspects of curcumin in human systems. Still, further randomized clinical studies in different ethnic populations warrant its transition to a marketed drug. This review summarizes the results from different clinical trials of curcumin-based therapeutics in the prevention and treatment of various chronic diseases.

Celastrol in cancer therapy: Recent developments, challenges and prospects

Cancer is one of the world's biggest healthcare burdens and despite the current advancements made in treatment plans, the outcomes for oncology patients have yet to reach their full potential. Hence, there is a pressing need to develop novel anti-cancer drugs. A popular drug class for research are natural compounds, due to their multi-targeting potential and enhanced safety profile. One such promising natural bioactive compound derived from a vine, Tripterygium wilfordii is celastrol. Pre-clinical studies revolving around the use of celastrol have revealed positive pharmacological activities in various types of cancers, thus suggesting the chemical's potential anti-cancerous effects. However, despite the numerous preclinical studies carried out over the past few decades, celastrol has not reached human trials for cancer. In this review, we summarize the mechanisms and therapeutic potentials of celastrol in treatment for different types of cancer. Subsequently, we also explore the possible reasons hindering its development for human use as cancer therapy, like its narrow therapeutic window and poor pharmacokinetic properties. Additionally, after critically analysing both in vitro and in vivo evidence, we discuss about the key pathways effected by celastrol and the suitable types of cancer that can be targeted by the natural drug, thus giving insight into future directions that can be taken, such as in-depth analysis and research of the druggability of celastrol derivatives, to aid the clinical translation of this promising anti-cancer lead compound.

Targeting the JAK-STAT pathway in autoimmune diseases and cancers: A focus on molecular mechanisms and therapeutic potential

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway is characterized by diverse immune regulatory systems involving cell proliferation, survival, and inflammation and immune tolerance. Aberrant JAK/STAT transduction activates proinflammatory cytokine signaling that jeopardize the immune balance and thus contributes to the development of autoimmune diseases and cancer progression. The success of several small-molecule JAK inhibitors in the treatment of rheumatologic diseases demonstrates that targeting the JAK/STAT pathway is efficient in suppressing inflammation and sheds light on their therapeutic potential in several autoimmune diseases and cancers. In this review, we discuss the signal transduction and molecular mechanism involving immune function through the JAK-STAT pathway, outline the role of this pathway in autoimmunity and oncoimmunology, and explain the preclinical and clinical trial evidence for the therapeutic potential of targeting the JAK-STAT signaling pathway. Issues regarding the safety and clinical efficacy of JAK inhibitors are reviewed. Ongoing studies are addressed with a focus on emerging indications for JAK inhibition and explanations of the novel mechanisms of JAK-STAT signaling blockade.

Chemical composition and pharmacological bio-efficacy of Parrotiopsis jacquemontiana (Decne) Rehder for anticancer activity

Consistent STAT3 (Single transducer and activator of transcription 3) activation is observed in many tumors and promotes malignant cell transformation. In the present investigation, we evaluated the anticancer effects of Parrotiopsis jacquemontiana methanol fraction (PJM) on STAT3 inhibition in HCCLM3 and MDA-MB 231 cells. PJM suppressed the activation of upstream kinases i.e. JAK-1/2 (Janus kinase-1/2), and c-Src (Proto-oncogene tyrosine-protein kinase c-Src), and upregulated the expression levels of PIAS-1/3 (Protein Inhibitor of Activated STATs-1/3), SHP-1/2 (Src-homology region 2 domain-containing phosphatase-1/2), and PTP-1β (Protein tyrosine phosphatase 1 β) which negatively regulate STAT3 signaling pathway. PJM also decreased the levels of protein products conferring to various oncogenes, which in turn repressed the proliferation, migration, invasion, and induced apoptosis in cancer cell lines. The growth inhibitory effects of PJM on cell-cycle and metastasis were correlated with decreased expression levels of CyclinD1, CyclinE, MMP-2 (Matrix metalloproteinases-2), and MMP-9 (Matrix metalloproteinases-9). Induction of apoptosis was indicated by the cleavage and subsequent activation of Caspases (Cysteine-dependent Aspartate-directed Proteases) i.e. caspase-3, 7, 8, 9, and PARP (Poly (ADP-ribose) polymerase) as well as through the down-regulation of anti-apoptotic proteins. These apoptotic effects of PJM were preceded by inhibition of STAT3 cell-signaling pathway. STAT3 was needed for PJM-induced apoptosis, and inhibition of STAT3 via pharmacological inhibitor (Stattic; SC-203282) abolished the apoptotic effects. Conclusively, our results demonstrate the capability of PJM to inhibit cancer cell-proliferation and induce apoptosis by suppressing STAT3 via upregulation of STAT3 inhibitors and pro-apoptotic proteins whereas the down-regulation of upstream kinases and anti-apoptotic protein expression. In future, one-step advance studies of PHM regarding its role in metastatic inhibition, immune response modulation for reducing tumor, and inducing apoptosis in suitable animal models would be an interesting and promising research area.

Pyrimethamine Modulates Interplay between Apoptosis and Autophagy in Chronic Myelogenous Leukemia Cells

Pyrimethamine (Pyri) is being used in combination with other medications to treat serious parasitic infections of the body, brain, or eye and to also reduce toxoplasmosis infection in the patients with HIV infection. Additionally, Pyri can display significant anti-cancer potential in different tumor models, but the possible mode of its actions remains unclear. Hence, in this study, the possible anti-tumoral impact of Pyri on human chronic myeloid leukemia (CML) was deciphered. Pyri inhibited cell growth in various types of tumor cells and exhibited a marked inhibitory action on CML cells. In addition to apoptosis, Pyri also triggered sustained autophagy. Targeted inhibition of autophagy sensitized the tumor cells to Pyri-induced apoptotic cell death. Moreover, the activation of signal transducer and activator of transcription 5 (STAT5) and its downstream target gene Bcl-2 was attenuated by Pyri. Accordingly, small interfering RNA (siRNA)-mediated STAT5 knockdown augmented Pyri-induced autophagy and apoptosis and promoted the suppressive action of Pyri on cell viability. Moreover, ectopic overexpression of Bcl-2 protected the cells from Pyri-mediated autophagy and apoptosis. Overall, the data indicated that the attenuation of STAT5-Bcl-2 cascade by Pyri can regulate its growth inhibitory properties by simultaneously targeting both apoptosis and autophagy cell death mechanism(s).