STAT3 is necessary for proliferation and survival in colon cancer-initiating cells

CD58 defines regulatory macrophages within the tumor microenvironment

CD58 has been implicated in immune suppression and is associated with stemness in various types of cancer. Nonetheless, efficient biomarkers for assessing cancer patient response to immunotherapy are lacking. The present work focused on assessing the immune predictive significance of CD58 for patients with glioma. The expression of CD58 correlates with the clinicopathologic characteristics of patients with glioma, suggesting CD58high cells to signify glioma with tumorigenic potential. The CD58high cells displayed accelerated tumor formation compared to CD58low cells in vivo. Taken together, CD58 could potentially serve as a marker for glioma. CD58high glioma induces macrophage polarization through CXCL5 secretion, where M2 macrophages regulate PD-L1 expression within CD58high glioma via IL-6 production in vitro. Moreover, it was found that combination treatment with CD58 significantly increased the volume of tumors in the xenograft specimens. Evaluating CD58 expression represents a promising approach for identifying patients who can benefit from immunotherapy.

The interferon/STAT1 signaling axis is a common feature of tumor-initiating cells in breast cancer

A tumor cell subpopulation of tumor-initiating cells (TIC), or "cancer stem cells", are associated with therapeutic resistance, as well as both local and distant recurrence. Enriched populations of TIC are identified by markers including aldehyde dehydrogenase (ALDH1) activity, the cell surface marker combination CD44 + /CD24 - , or fluorescent reporters for signaling pathways that regulate TIC function. We showed previously that S ignal T ransducer and A ctivator of T ranscription (STAT)-mediated transcription allows enrichment for TIC in claudin-low models of human triple-negative breast cancer using a STAT-responsive reporter. However, the molecular phenotypes of STAT TIC are not well understood, and there is no existing method to lineage-trace TIC as they undergo cell state changes. Using a new STAT-responsive lineage-tracing (LT) system in conjunction with our original reporter, we enriched for cells with enhanced mammosphere-forming potential in some, but not all, basal-like triple-negative breast cancer (TNBC) xenograft models (TNBC) indicating TIC-related and TIC-independent functions for STAT signaling. Single-cell RNA sequencing (scRNAseq) of reporter-tagged xenografts and clinical samples identified a common interferon (IFN)/STAT1-associated transcriptional state, previously linked to inflammation and macrophage differentiation, in TIC. Surprisingly, most of the genes we identified are not present in previously published TIC signatures derived using bulk RNA sequencing. Finally, we demonstrated that bone marrow stromal cell antigen 2 (BST2), is a cell surface marker of this state, and that it functionally regulates TIC frequency. These results suggest TIC may exploit the IFN/STAT1 signaling axis to promote their activity, and that targeting this pathway may help eliminate TIC.

Significance

TIC differentially express interferon response genes, which were not previously reported in bulk RNA sequencing-derived TIC signatures, highlighting the importance of coupling single-cell transcriptomics with enrichment to derive TIC signatures.

Cell-cell communication: new insights and clinical implications

Multicellular organisms are composed of diverse cell types that must coordinate their behaviors through communication. Cell-cell communication (CCC) is essential for growth, development, differentiation, tissue and organ formation, maintenance, and physiological regulation. Cells communicate through direct contact or at a distance using ligand-receptor interactions. So cellular communication encompasses two essential processes: cell signal conduction for generation and intercellular transmission of signals, and cell signal transduction for reception and procession of signals. Deciphering intercellular communication networks is critical for understanding cell differentiation, development, and metabolism. First, we comprehensively review the historical milestones in CCC studies, followed by a detailed description of the mechanisms of signal molecule transmission and the importance of the main signaling pathways they mediate in maintaining biological functions. Then we systematically introduce a series of human diseases caused by abnormalities in cell communication and their progress in clinical applications. Finally, we summarize various methods for monitoring cell interactions, including cell imaging, proximity-based chemical labeling, mechanical force analysis, downstream analysis strategies, and single-cell technologies. These methods aim to illustrate how biological functions depend on these interactions and the complexity of their regulatory signaling pathways to regulate crucial physiological processes, including tissue homeostasis, cell development, and immune responses in diseases. In addition, this review enhances our understanding of the biological processes that occur after cell-cell binding, highlighting its application in discovering new therapeutic targets and biomarkers related to precision medicine. This collective understanding provides a foundation for developing new targeted drugs and personalized treatments.

Carnosic acid: an effective phenolic diterpenoid for prevention and management of cancers via targeting multiple signaling pathways

Cancer is a serious global public health issue, and a great deal of research has been made to treat cancer. Of these, discovery of promising compounds that effectively fight cancer always has been the main point of interest in pharmaceutical research. Carnosic acid (CA) is a phenolic diterpenoid compound widely present in Lamiaceae plants such as Rosemary (Rosmarinus officinalis L.). In recent years, there has been increasing evidence that CA has significant anti-cancer activity, such as leukaemia, colorectal cancer, breast cancer, lung cancer, liver cancer, pancreatic cancer, stomach cancer, lymphoma, prostate cancer, oral cancer, etc. The potential mechanisms involved by CA, including inhibiting cell proliferation, inhibiting metastasis, inducing cell apoptosis, stimulating autophagy, regulating the immune system, reducing inflammation, regulating the gut microbiota, and enhancing the effects of other anti-cancer drugs. This article reviews the biosynthesis, pharmacokinetics and metabolism, safety and toxicity, as well as the molecular mechanisms and signaling pathways of the anticancer activity of CA. This will contribute to the development of CA or CA-containing functional foods for the prevention and treatment of cancer, providing important advances in the advancement of cancer treatment strategies.

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.

Oncogenic STAT Transcription Factors as Targets for Cancer Therapy: Innovative Strategies and Clinical Translation

Despite advances in our understanding of molecular aspects of oncogenesis, cancer remains a leading cause of death. The malignant behavior of a cancer cell is driven by the inappropriate activation of transcription factors. In particular, signal transducers and activators of transcription (STATs), which regulate many critical cellular processes such as proliferation, apoptosis, and differentiation, are frequently activated inappropriately in a wide spectrum of human cancers. Multiple signaling pathways converge on the STATs, highlighting their importance in the development and progression of oncogenic diseases. STAT3 and STAT5 are two members of the STAT protein family that are the most frequently activated in cancers and can drive cancer pathogenesis directly. The development of inhibitors targeting STAT3 and STAT5 has been the subject of intense investigations in the last decade, although effective treatment options remain limited. In this review, we investigate the specific roles of STAT3 and STAT5 in normal physiology and cancer biology, discuss the opportunities and challenges in pharmacologically targeting STAT proteins and their upstream activators, and offer insights into novel therapeutic strategies to identify STAT inhibitors as cancer therapeutics.

Unveiling the landscape of cytokine research in glioma immunotherapy: a scientometrics analysis

Background: Cytokines modulate the glioma tumor microenvironment, influencing occurrence, progression, and treatment response. Strategic cytokine application may improve glioma immunotherapy outcomes. Gliomas remain refractory to standard therapeutic modalities, but immunotherapy shows promise given the integral immunomodulatory roles of cytokines. However, systematic evaluation of cytokine glioma immunotherapy research is absent. Bibliometric mapping of the research landscape, recognition of impactful contributions, and elucidation of evolutive trajectories and hot topics has yet to occur, potentially guiding future efforts. Here, we analyzed the structure, evolution, trends, and hotspots of the cytokine glioma immunotherapy research field, subsequently focusing on avenues for future investigation. Methods: This investigation conducted comprehensive bibliometric analyses on a corpus of 1529 English-language publications, from 1 January 2000, to 4 October 2023, extracted from the Web of Science database. The study employed tools including Microsoft Excel, Origin, VOSviewer, CiteSpace, and the Bibliometrix R package, to systematically assess trends in publication, contributions from various countries, institutions, authors, and journals, as well as to examine literature co-citation and keyword distributions within the domain of cytokines for glioma immunotherapy. The application of these methodologies facilitated a detailed exploration of the hotspots, the underlying knowledge structure, and the developments in the field of cytokines for glioma immunotherapy. Results: This bibliometric analysis revealed an exponential growth in annual publications, with the United States, China, and Germany as top contributors. Reviews constituted 17% and research articles 83% of total publications. Analysis of keywords like "interleukin-13," "TGF-beta," and "dendritic cells" indicated progression from foundational cytokine therapies to sophisticated understanding of the tumor microenvironment and immune dynamics. Key research avenues encompassed the tumor microenvironment, epidermal growth factor receptor, clinical trials, and interleukin pathways. This comprehensive quantitative mapping of the glioma immunotherapy cytokine literature provides valuable insights to advance future research and therapeutic development. Conclusion: This study has identified remaining knowledge gaps regarding the role of cytokines in glioma immunotherapy. Future research will likely focus on the tumor microenvironment, cancer vaccines, epidermal growth factor receptor, and interleukin-13 receptor alpha 2. Glioma immunotherapy development will continue through investigations into resistance mechanisms, microglia and macrophage biology, and interactions within the complex tumor microenvironment.

Deregulated transcription factors in the emerging cancer hallmarks

Cancer progression is a multifaceted process that entails several stages and demands the persistent expression or activation of transcription factors (TFs) to facilitate growth and survival. TFs are a cluster of proteins with DNA-binding domains that attach to promoter or enhancer DNA strands to start the transcription of genes by collaborating with RNA polymerase and other supporting proteins. They are generally acknowledged as the major regulatory molecules that coordinate biological homeostasis and the appropriate functioning of cellular components, subsequently contributing to human physiology. TFs proteins are crucial for controlling transcription during the embryonic stage and development, and the stability of different cell types depends on how they function in different cell types. The development and progression of cancer cells and tumors might be triggered by any anomaly in transcription factor function. It has long been acknowledged that cancer development is accompanied by the dysregulated activity of TF alterations which might result in faulty gene expression. Recent studies have suggested that dysregulated transcription factors play a major role in developing various human malignancies by altering and rewiring metabolic processes, modifying the immune response, and triggering oncogenic signaling cascades. This review emphasizes the interplay between TFs involved in metabolic and epigenetic reprogramming, evading immune attacks, cellular senescence, and the maintenance of cancer stemness in cancerous cells. The insights presented herein will facilitate the development of innovative therapeutic modalities to tackle the dysregulated transcription factors underlying cancer.

Cancer Stem Cells in Colorectal Cancer: Implications for Targeted Immunotherapies

PURPOSE

Colorectal cancers are composed of heterogeneous cell populations in the concepts of genetic and functional degrees that among them cancer stem cells are identified with their self-renewal and stemness capability mediating primary tumorigenesis, metastasize, therapeutic resistance, and tumor recurrence. Therefore, understanding the key mechanisms of stemness in colorectal cancer stem cells (CRCSCs) provides opportunities to discover new treatments or improve existing therapeutic regimens.

METHODS

We review the biological significance of stemness and the results of potential CRCSC-based targeted immunotherapies. Then, we pointed out the barriers to targeting CRCSCs in vivo and highlight new strategies based on synthetic and biogenic nanocarriers for the development of future anti-CRCSC trials.

RESULTS

The CSCs' surface markers, antigens, neoantigens, and signaling pathways supportive CRCSCs or immune cells that are interacted with CRCSCs could be targeted by immune monotherapy or in formulation with developed nanocarriers to overcome the resistant mechanisms in immune evader CRCSCs.

CONCLUSION

Identification molecular and cellular cues supporting stemness in CRCSCs and their targeting by nanoimmunotherpy can improve the efficacy of existed therapies or explore novel therapeutic options in future.

Oligonucleotide-Based Therapeutics for STAT3 Targeting in Cancer-Drug Carriers Matter

High expression and phosphorylation of signal transducer and transcription activator 3 (STAT3) are correlated with progression and poor prognosis in various types of cancer. The constitutive activation of STAT3 in cancer affects processes such as cell proliferation, apoptosis, metastasis, angiogenesis, and drug resistance. The importance of STAT3 in cancer makes it a potential therapeutic target. Various methods of directly and indirectly blocking STAT3 activity at different steps of the STAT3 pathway have been investigated. However, the outcome has been limited, mainly by the number of upstream proteins that can reactivate STAT3 or the relatively low specificity of the inhibitors. A new branch of molecules with significant therapeutic potential has emerged thanks to recent developments in the regulatory function of non-coding nucleic acids. Oligonucleotide-based therapeutics can silence target transcripts or edit genes, leading to the modification of gene expression profiles, causing cell death or restoring cell function. Moreover, they can reach untreatable targets, such as transcription factors. This review briefly describes oligonucleotide-based therapeutics that found application to target STAT3 activity in cancer. Additionally, this review comprehensively summarizes how the inhibition of STAT3 activity by nucleic acid-based therapeutics such as siRNA, shRNA, ASO, and ODN-decoy affected the therapy of different types of cancer in preclinical and clinical studies. Moreover, due to some limitations of oligonucleotide-based therapeutics, the importance of carriers that can deliver nucleic acid molecules to affect the STAT3 in cancer cells and cells of the tumor microenvironment (TME) was pointed out. Combining a high specificity of oligonucleotide-based therapeutics toward their targets and functionalized nanoparticles toward cell type can generate very efficient formulations.

AKAP12 promotes cancer stem cell-like phenotypes and activates STAT3 in colorectal cancer

BACKGROUND

Cancer stem cells (CSCs) have unique biological characteristics, including tumorigenicity, immortality, and chemoresistance. Colorectal CSCs have been identified and isolated from colorectal cancers by various methods. AKAP12, a scaffolding protein, is considered to act as a potential suppressor in colorectal cancer, but its role in CSCs remains unknown. In this study, we investigated the function of AKAP12 in Colorectal CSCs.

METHODS

Herein, Colorectal CSCs were enriched by cell culture with a serum-free medium. CSC-associated characteristics were evaluated by Flow cytometry assay and qPCR. AKAP12 gene expression was regulated by lentiviral transfection assay. The tumorigenicity of AKAP12 in vivo by constructing a tumor xenograft model. The related pathways were explored by qPCR and Western blot.

RESULTS

The depletion of AKAP12 reduced colony formation, sphere formation, and expression of stem cell markers in colorectal cancer cells, while its knockdown decreased the volume and weight of tumor xenografts in vivo. AKAP12 expression levels also affected the expression of stemness markers associated with STAT3, potentially via regulating the expression of protein kinase C.

CONCLUSION

This study suggests Colorectal CSCs overexpress AKAP12 and maintain stem cell characteristics through the AKAP12/PKC/STAT3 pathway. AKAP12 may be an important therapeutic target for blocking the development of colorectal cancer in the field of cancer stem cells.

Transcription activation of SPINK4 by ELF-1 augments progression of colon cancer by regulating biological behaviors

BACKGROUND

SPINK4 was highly expressed in colorectal cancer and resulted in worse prognosis of colorectal cancer patients. However, the expression and function of SPINK4 in colon cancer have not been revealed.

METHODS

Analysis from GEPIA website showed the expression and function of SPINK4 in colon cancer samples. Colon cancer cell lines were applied to detect the biological function of SPINK4. Functionally, the transcriptional factor of SPINK4 has been predicted and verified. Finally, the associations between transcriptional factor and SPINK4 have been confirmed.

RESULTS

SPINK4 expression was obviously increased in colon cancer samples. HCT-116 and DXH-1 cells in si-SPINK4-1 or si-SPINK4-2 group displayed an obvious reduction in its proliferation, cell cycle, invasion and migration compared to those in the si-control group. Moreover, transcriptional factor ELF-1 bound to the promoter of SPINK4 and affected its expression in colon cancer cells. High ELF-1 expression was presented in colon cancer samples and resulted in worse prognosis of colon cancer patients. Additionally, si-SPINK4 antagonized the function of ELF-1 overexpression in modulating colon cancer cell proliferation, cell cycle and mobility.

CONCLUSIONS

Our findings afforded a theoretical basis for further research on the treatment of colon cancer based on the control of ELF-1/SPINK4 expression.

Dual-responsive PEG-lipid polyester nanoparticles for siRNA and vaccine delivery elicit anti-cancer immune responses by modulating tumor microenvironment

Cancer vaccine-based immunotherapy has great potential; however, the vaccines have been hindered by the immunosuppressive tumor microenvironment (TME). In this study, dual-responsive PEG-lipid polyester nanoparticles (PEG BR647-NPs) for tumor-targeted delivery were proposed. PEG BR647-NPs containing the model tumor-associated antigen (TAA) OVA and the signal transduction and activator of transcription 3 (STAT3) siRNA were delivered to the tumor. The PEG BR647-NPs were internalized by tumor-associated dendritic cells (TADCs), where the TAA and siRNA were released into the cytoplasm via the endo/lysosome escape effect. The released OVA was presented by the major histocompatibility complex class I to activate T cells, and the released STAT3 siRNA acted to relieve TADC dysfunction, promote TADC maturation, improve antigen-presenting ability, and enhance anticancer T cell immunity. Meanwhile, the PEG BR647-NPs were ingested by tumor cells, killing them by the pro-apoptosis effect of STAT3 siRNA. Moreover, PEG BR647-NPs could reduce the proportion of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in tumors and abrogate immunosuppression. The integration of relieved TADC dysfunction, promoted TADC maturation, enhanced antigen cross-presentation, abrogated immunosuppression, and improved pro-apoptosis effect boosted the vaccination for tumor immunotherapy. Thus, PEG BR647-NPs efficiently delivered the vaccine and STAT3 siRNA to the tumor and modulated immunosuppressive TME, thus providing better antitumor effects.

Diffusion-enhanced characterization of 3D chromatin structure reveals its linkage to gene regulatory networks and the interactome

The interactome networks at the DNA, RNA, and protein levels are crucial for cellular functions, and the diverse variations of these networks are heavily involved in the establishment of different cell states. We have developed a diffusion-based method, Hi-C to geometry (CTG), to obtain reliable geometric information on the chromatin from Hi-C data. CTG produces a consistent and reproducible framework for the 3D genomic structure and provides a reliable and quantitative understanding of the alterations of genomic structures under different cellular conditions. The genomic structure yielded by CTG serves as an architectural blueprint of the dynamic gene regulatory network, based on which cell-specific correspondence between gene-gene and corresponding protein-protein physical interactions, as well as transcription correlation, is revealed. We also find that gene fusion events are significantly enriched between genes of short CTG distances and are thus close in 3D space. These findings indicate that 3D chromatin structure is at least partially correlated with downstream processes such as transcription, gene regulation, and even regulatory networking through affecting protein-protein interactions.

Nuclear export signal mutation of epidermal growth factor receptor enhances malignant phenotypes of cancer cells

Nuclear epidermal growth factor receptor (EGFR) has been shown to be correlated with drug resistance and a poor prognosis in patients with cancer. Previously, we have identified a tripartite nuclear localization signal (NLS) within EGFR. To comprehensively determine the functions and underlying mechanism of nuclear EGFR and its clinical implications, we aimed to explore the nuclear export signal (NES) sequence of EGFR that is responsible for interacting with the exportins. We combined in silico prediction with site-directed mutagenesis approaches and identified a putative NES motif of EGFR, which is located in amino acid residues 736-749. Mutation at leucine 747 (L747) in the EGFR NES led to increased nuclear accumulation of the protein via a less efficient release of the exportin CRM1. Interestingly, L747 with serine (L747S) and with proline (L747P) mutations were found in both tyrosine kinase inhibitor (TKI)-treated and -naïve patients with lung cancer who had acquired or de novo TKI resistance and a poor outcome. Reconstituted expression of the single NES mutant EGFRL747P or EGFRL747S, but not the dual mutant along with the internalization-defective or NLS mutation, in lung cancer cells promoted malignant phenotypes, including cell migration, invasiveness, TKI resistance, and tumor initiation, supporting an oncogenic role of nuclear EGFR. Intriguingly, cells with germline expression of the NES L747 mutant developed into B cell lymphoma. Mechanistically, nuclear EGFR signaling is required for sustaining nuclear activated STAT3, but not for Erk. These findings suggest that EGFR functions are compartmentalized and that nuclear EGFR signaling plays a crucial role in tumor malignant phenotypes, leading to tumorigenesis in human cancer.

The complex network of transcription factors, immune checkpoint inhibitors and stemness features in colorectal cancer: A recent update

Cancer immunity is regulated by several mechanisms that include co-stimulatory and/or co-inhibitory molecules known as immune checkpoints expressed by the immune cells. In colorectal cancer (CRC), CTLA-4, LAG3, TIM-3 and PD-1 are the major co-inhibitory checkpoints involved in tumor development and progression. On the other hand, the deregulation of transcription factors and cancer stem cells activity plays a major role in the development of drug resistance and in the spread of metastatic disease in CRC. In this review, we describe how the modulation of such transcription factors affects the response of CRC to therapies. We also focus on the role of cancer stem cells in tumor metastasis and chemoresistance and discuss both preclinical and clinical approaches for targeting stem cells to prevent their tumorigenic effect. Finally, we provide an update on the clinical applications of immune checkpoint inhibitors in CRC and discuss the regulatory effects of transcription factors on the expression of the immune inhibitory checkpoints with specific focus on the PD-1 and PD-L1 molecules.

Epibrassinolide impaired colon tumor progression and induced autophagy in SCID mouse xenograft model via acting on cell cycle progression without affecting endoplasmic reticulum stress observed in vitro

Epibrassinolide is a member of brassinosteroids with a polyhydroxysteroid structure similar to steroid hormones of vertebrates. It was shown that EBR decreased cell proliferation and induced apoptosis in different colon cancer cell lines without exerting a cytotoxic effect in epithelial fetal human colon cells. This finding highlighted the potential of epibrassinolide in clinical therapeutic setup. In our previous studies, we showed that epibrassinolide was able to induce apoptosis via endoplasmic reticulum stress. Recently, we also showed that endoplasmic reticulum and apoptotic stresses can be prevented via autophagic induction in non-cancerous epithelial or aggressive forms of cancer cells. Therefore, here in this study, we evaluated the anti-tumoral effect of epibrassinolide as well as the autophagy involvement in the aggressive forms of colon cancer cell lines as well as in vivo SCID mouse xenograft colon cancer model for the first time. For this purpose, SCID mouse model was used for subcutaneous injection of colon cancer cells in matrigel formulation. We found that autophagy is induced in both in vitro and in vivo models. Following tumor formation, SCID mice were treated daily with increasing concentrations of epibrassinolide for two weeks. Our findings showed that EBR inhibited the volume and diameter of the tumor in a dose-dependent manner by causing cell cycle arrest. Therefore our data suggest that epibrassinolide exerts a cytostatic effect on the agrressive form of colon cancer model in vivo, without affecting endoplasmic reticulum stress and the induction of autophagy might have role in this effect of epibrassinolide.

STAT3 promotes RNA polymerase III-directed transcription by controlling the miR-106a-5p/TP73 axis

Deregulation of Pol III products causes a range of diseases, including neural diseases and cancers. However, the factors and mechanisms that modulate Pol III-directed transcription remain to be found, although massive advances have been achieved. Here, we show that STAT3 positively regulates the activities of Pol III-dependent transcription and cancer cell growth. RNA-seq analysis revealed that STAT3 inhibits the expression of TP73, a member of the p53 family. We found that TP73 is not only required for the regulation of Pol III-directed transcription mediated by STAT3 but also independently suppresses the synthesis of Pol III products. Mechanistically, TP73 can disrupt the assembly of TFIIIB subunits and inhibit their occupancies at Pol III target loci by interacting with TFIIIB subunit TBP. MiR-106a-5p can activate Pol III-directed transcription by targeting the TP73 mRNA 3' UTR to reduce TP 73 expression. We show that STAT3 activates the expression of miR-106a-5p by binding to the miRNA promoter, indicating that the miR-106a-5p links STAT3 with TP73 to regulate Pol III-directed transcription. Collectively, these findings indicate that STAT3 functions as a positive regulator in Pol III-directed transcription by controlling the miR-106a-5p/TP73 axis.

Transcriptional factors targeting in cancer stem cells for tumor modulation

Cancer Stem Cells (CSCs) are now considered the primary "seeds" for the onset, development, metastasis, and recurrence of tumors. Despite therapeutic breakthroughs, cancer remains the leading cause of death worldwide. This is because the tumor microenvironment contains a key population of cells known as CSCs, which promote tumor aggression. CSCs are self-renewing cells that aid tumor recurrence by promoting tumor growth and persisting in patients after many traditional cancer treatments. According to reports, numerous transcription factors (TF) play a key role in maintaining CSC pluripotency and its self-renewal property. The understanding of the functions, structures, and interactional dynamics of these transcription factors with DNA has modified the hypothesis, paving the way for novel transcription factor-targeted therapies. These TFs, which are crucial and are required by cancer cells, play a vital function in the etiology of human cancer. Such CSC TFs will help with gene expression profiling, which provides crucial data for predicting the prognosis of patients. To overcome anti-cancer medication resistance and completely eradicate cancer, a potent therapy combining TFs-based CSC targets with traditional chemotherapy may be developed. In order to develop therapies that could eliminate CSCs, we here concentrated on the effect of TFs and other components of signalling pathways on cancer stemness.

TRIM27-USP7 complex promotes tumour progression via STAT3 activation in human hepatocellular carcinoma

BACKGROUND & AIMS

TRIM27 is stabilized by binding to USP7 and mediates tumour progression in several cancers; however, the roles of TRIM27-USP7 complex on STAT3 activation in HCC are unknown.

METHODS

Regulations and functions of TRIM27 for activating STAT3 in HCC were assessed using 207 HCC samples or HCC cells.

RESULTS

TRIM27 expression was increased in some cases of HCC. High TRIM27 expression was an independent predictor for poor prognosis in HCC after surgery. It was correlated with the expression of EpCAM, vimentin, MMP-9, and activation of STAT3 in HCC. TRIM27 expression was correlated with USP7 expression, and HCC with high TRIM27 expression together with high USP7 expression showed enhanced STAT3 activation, resulting in poorer prognosis. p-JAK1 expression was correlated with STAT3 activation in HCC with high TRIM27 expression. In vitro, USP7 knockdown decreased TRIM27 expression, suggesting that USP7 was essential for TRIM27 stabilization. Knocking down of TRIM27 or USP7 suppressed STAT3 activation and overexpression of TRIM27 accelerated STAT3 activation; therefore, the formation of TRIM27-USP7 complex was needed for STAT3 activation, which led to aggressive tumour proliferation and invasion by enhancing EMT and CSC-like property. Binding of JAK1 to TRIM27-USP7 complex was confirmed in vitro. Deletion of TRIM27-USP7 complex by USP7 inhibitor significantly inhibited tumour cell invasion by suppressing STAT3 activation.

CONCLUSIONS

TRIM27 is stabilized by binding to USP7 and is related to aggressive tumour progression in HCC via STAT3 activation, resulting in poor prognosis after operation. Therefore, TRIM27-USP7 complex is a useful prognostic predictor and a promising therapeutic target for HCC.

Ursolic acid: a natural modulator of signaling networks in different cancers

Incidence rate of cancer is estimated to increase by 40% in 2030. Furthermore, the development of resistance against currently available treatment strategies has contributed to the cancer-associated mortality. Scientists are now looking for the solutions that could help prevent the disease occurrence and could provide a pain-free treatment alternative for cancers. Therefore, efforts are now put to find a potent natural compound that could sever this purpose. Ursolic acid (UA), a triterpene acid, has potential to inhibit the tumor progression and induce sensitization to conventional treatment drugs has been documented. Though, UA is a hydrophobic compound therefore it is usually chemically modified to increase its bioavailability prior to administration. However, a thorough literature indicating its mechanism of action and limitations for its use at clinical level was not reviewed. Therefore, the current study was designed to highlight the potential mechanism of UA, its anti-cancer properties, and potential applications as therapeutic compound. This endeavour is a valuable contribution in understanding the hurdles preventing the translation of its potential at clinical level and provides foundations to design new studies that could help enhance its bioavailability and anti-cancer potential for various cancers.

Effect of Antibiotic Amphotericin B Combinations with Selected 1,3,4-Thiadiazole Derivatives on RPTECs in an In Vitro Model

4-(5-methyl-1,3,4-thiadiazole-2-yl) benzene-1,3-diol (C1) and 4-[5-(naphthalen-1-ylmethyl)-1,3,4-thiadiazol-2-yl] benzene1,3-diol (NTBD) are representative derivatives of the thiadiazole group, with a high antimycotic potential and minimal toxicity against normal human fibroblast cells. The present study has proved its ability to synergize with the antifungal activity of AmB. The aim of this work was to evaluate the cytotoxic effects of C1 or NTBD, alone or in combination with AmB, on human renal proximal tubule epithelial cells (RPTECs) in vitro. Cell viability was assessed with the MTT assay. Flow cytometry and spectrofluorimetric techniques were used to assess the type of cell death and production of reactive oxygen species (ROS), respectively. The ELISA assay was performed to measure the caspase-2, -3, and -9 activity. ATR-FTIR spectroscopy was used to evaluate biomolecular changes in RPTECs induced by the tested formulas. The combinations of C1/NTBD and AmB did not exert a strong inhibitory effect on the viability/growth of kidney cells, as evidenced by the negligible changes in the apoptotic/necrotic rate and caspase activity, compared to the control cells. Both NTBD and C1 displayed stronger anti-oxidant activity when combined with AmB. The relatively low nephrotoxicity of the thiadiazole derivative combinations and the protective activity against AmB-induced oxidative stress may indicate their potential use in the therapy of fungal infections.

Toxicity of tributyltin chloride on haarder (Liza haematocheila) after its acute exposure: Bioaccumulation, antioxidant defense, histological, and transcriptional analyses

Liza haematocheila is exposed to various chemical contaminants from anthropogenic sources, including tributyltin chloride (TBTC). Yet the toxicity mechanism of TBTC on haarder remains unclear. The haarder was exposed to different doses (0, 10%, 20%, and 50% of LC₅₀-96 h) of TBTC. In this study, the results revealed its high bioaccumulation in the livers and significant alteration for development. The activities of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase decreased after 96-h exposure to TBTC, this accompanied by an increased malondialdehyde level. TBTC exposure caused the intense production of reactive oxygen species, a reduction in total blood cell count in serum, and apoptosis-related alterations in livers, indicating that enhanced oxidative stress occurred in the process of TBTC exposure. Histological results revealed angiorrhexis and infiltration of inflammatory cells, vacuolar degeneration of hepatocytes in the livers, and swelling, fusion, and disintegration of gill organs. Interestingly, the obtained transcriptional profiles indicated that high doses of TBTC caused energy disorder, apoptosis, and adipogenesis restriction mediated by cytokines and adipokines in Jak-STAT and adipocytokine signaling pathways. In summary, acute exposure to high doses of TBTC could impair the antioxidant system and pathways related to energy, apoptosis and adipogenesis, eventually posing a serious challenge to the fitness of haarder individuals and its fish populations as marine resources.

Heat Shock Protein 27 Affects Myeloid Cell Activation and Interaction with Prostate Cancer Cells

Heat shock proteins are cytoprotective molecules induced by environmental stresses. The small heat shock protein 27 (Hsp27) is highly expressed under oxidative stress conditions, mediating anti-oxidative effects and blocking apoptosis. Since medical gas plasma treatment subjects cancer cells to a multitude of reactive oxygen species (ROS), inducing apoptosis and immunomodulation, probable effects of Hsp27 should be investigated. To this end, we quantified the extracellular Hsp27 in two prostate cancer cell lines (LNCaP, PC-3) after gas plasma-induced oxidative stress, showing a significantly enhanced release. To investigate immunomodulatory effects, two myeloid cell lines (THP-1 and HL-60) were also exposed to Hsp27. Only negligible effects on viability, intracellular oxidative milieu, and secretion profiles of the myeloid cells were found when cultured alone. Interestingly, prostate cancer-myeloid cell co-cultures showed altered secretion profiles with a significant decrease in vascular endothelial growth factor (VEGF) release. Furthermore, the myeloid surface marker profiles were changed, indicating an enhanced differentiation in co-culture upon Hsp27 treatment. Finally, we investigated morphological changes, proliferation, and interaction with prostate cancer cells, and found significant alterations in the myeloid cells, supporting the tendency to differentiate. Collectively, our results suggest an ambiguous effect of Hsp27 on myeloid cells in the presence of prostate cancer cells which needs to be further investigated.

IL-6: The Link Between Inflammation, Immunity and Breast Cancer

Breast cancer is one of the leading causes of mortality in females. Over the past decades, intensive efforts have been made to uncover the pathogenesis of breast cancer. Interleukin-6 (IL-6) is a pleiotropic factor which has a vital role in host defense immunity and acute stress. Moreover, a wide range of studies have identified the physiological and pathological roles of IL-6 in inflammation, immune and cancer. Recently, several IL-6 signaling pathway-targeted monoclonal antibodies have been developed for cancer and immune therapy. Combination of IL-6 inhibitory antibody with other pathways blockage drugs have demonstrated promising outcome in both preclinical and clinical trials. This review focuses on emerging studies on the strong linkages of IL-6/IL-6R mediated regulation of inflammation and immunity in cancer, especially in breast cancer.

MDACT: A New Principle of Adjunctive Cancer Treatment Using Combinations of Multiple Repurposed Drugs, with an Example Regimen

In part one of this two-part paper, we present eight principles that we believe must be considered for more effective treatment of the currently incurable cancers. These are addressed by multidrug adjunctive cancer treatment (MDACT), which uses multiple repurposed non-oncology drugs, not primarily to kill malignant cells, but rather to reduce the malignant cells' growth drives. Previous multidrug regimens have used MDACT principles, e.g., the CUSP9v3 glioblastoma treatment. MDACT is an amalgam of (1) the principle that to be effective in stopping a chain of events leading to an undesired outcome, one must break more than one link; (2) the principle of Palmer et al. of achieving fractional cancer cell killing via multiple drugs with independent mechanisms of action; (3) the principle of shaping versus decisive operations, both being required for successful cancer treatment; (4) an idea adapted from Chow et al., of using multiple cytotoxic medicines at low doses; (5) the idea behind CUSP9v3, using many non-oncology CNS-penetrant drugs from general medical practice, repurposed to block tumor survival paths; (6) the concept from chess that every move creates weaknesses and strengths; (7) the principle of mass-by adding force to a given effort, the chances of achieving the goal increase; and (8) the principle of blocking parallel signaling pathways. Part two gives an example MDACT regimen, gMDACT, which uses six repurposed drugs-celecoxib, dapsone, disulfiram, itraconazole, pyrimethamine, and telmisartan-to interfere with growth-driving elements common to cholangiocarcinoma, colon adenocarcinoma, glioblastoma, and non-small-cell lung cancer. gMDACT is another example of-not a replacement for-previous multidrug regimens already in clinical use, such as CUSP9v3. MDACT regimens are designed as adjuvants to be used with cytotoxic drugs.

Epigenetic Deregulation of Protein Tyrosine Kinase 6 Promotes Carcinogenesis of Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) accounts for over 90% of oral cancers and causes considerable morbidity and mortality. Epigenetic deregulation is a common mechanism underlying carcinogenesis. DNA methylation deregulation is the epigenetic change observed during the transformation of normal cells to precancerous and eventually cancer cells. This study investigated the DNA methylation patterns of PTK6 during the development of OSCC. Bisulfite genomic DNA sequencing was performed to determine the PTK6 methylation level. OSCC animal models were established to examine changes in PTK6 expression in the different stages of OSCC development. The DNA methylation of PTK6 was decreased during the development of OSCC. The mRNA and protein expression of PTK6 was increased in OSCC cell lines compared with human normal oral keratinocytes. In mice, the methylation level of PTK6 decreased after treatment with 4-nitroquinoline 1-oxide and arecoline, and the mRNA and protein expression of PTK6 was increased. PTK6 hypomethylation can be a diagnostic marker of OSCC. Upregulation of PTK6 promoted the proliferation, migration, and invasion of OSCC cells. PTK6 promoted carcinogenesis and metastasis by increasing STAT3 phosphorylation and ZEB1 expression. The epigenetic deregulation of PTK6 can serve as a biomarker for the early detection of OSCC and as a treatment target.

Exosome miR-3184-5p inhibits gastric cancer growth by targeting XBP1 to regulate the AKT, STAT3, and IRE1 signalling pathways

MicroRNAs can regulate the transcription of protein-coding genes associated with the development and progression of cancer. In this study, we explored the potential diagnostic function of exosome miR-3184-5p in gastric cancer. This exosome was isolated from the blood samples of 150 patients with gastric cancer and 60 healthy participants. The mean particle size and concentration of serum exosome in the patients with gastric cancer were 104.6 nm (93.97-115.84) and 6.21e+009 particles/ml (5.15e+009-7.12e+009), respectively. miR-3184-5p expression was substantially downregulated in the patients with gastric cancer compared with that in the healthy participants. The gastric cancer cell line HGC-27 was cultured and transfected with the mimic and an inhibitor to overexpress and inhibit miR-3184-5p expression. miR-3184-5p strongly suppressed cell proliferation, migration, and invasion but induced cell apoptosis. Luciferase reporter assay revealed that XBP1 was the target of miR-3184-5p. miR-3184-5p substantially downregulated the expression of CD44, cyclin D1, MMP2, p65, p-AKT, and p-STAT3 but upregulated that of GRP78, IRE1, p-JNK, and CHOP. Moreover, miR-3184-5p cleaved caspase-12 and inhibited BCL-2 expression. These results suggested that the downregulation of miR-3184-5p in patients with gastric cancer might regulate the AKT, STAT3, and IRE1 pathways to promote the vitality of gastric cancer cells.

Novel inhibitors of the STAT3 signaling pathway: an updated patent review (2014-present)

INTRODUCTION

STAT3 is a critical transcription factor that transmits signals from the cell surface to the nucleus, thus influencing the transcriptional regulation of some oncogenes. The inhibition of the activation of STAT3 is considered a promising strategy for cancer therapy. Numerous STAT3 inhibitors bearing different scaffolds have been reported to date, with a few of them having been considered in clinical trials.

AREAS COVERED

This review summarizes the advances on STAT3 inhibitors with different structural skeletons, focusing on the structure-activity relationships in the related patent literature published from 2014 to date.

EXPERT OPINION

Since the X-ray crystal structure of STAT3β homo dimer bound to DNA was solved in 1998, the development of STAT3 inhibitors has gone through a boom in recent years. However, none of them have been approved for marketing, probably due to the complex biological functions of the STAT3 signaling pathway, including its character and the poor drug-like physicochemical properties of its inhibitors. Nonetheless, targeting STAT3 continues to be an exciting field for the development of anti-tumor agents along with the emergence of new STAT3 inhibitors with unique mechanisms of action.

Inflammatory bowel disease-related colorectal cancer: Past, present and future perspectives

Inflammatory bowel disease-related colorectal cancer (IBD-CRC) is one of the most serious complications of IBD contributing to significant mortality in this cohort of patients. IBD is often associated with diet and lifestyle-related gut microbial dysbiosis, the interaction of genetic and environmental factors, leading to chronic gut inflammation. According to the “common ground hypothesis”, microbial dysbiosis and intestinal barrier impairment are at the core of the chronic inflammatory process associated with IBD-CRC. Among the many underlying factors known to increase the risk of IBD-CRC, perhaps the most important factor is chronic persistent inflammation. The persistent inflammation in the colon results in increased proliferation of cells necessary for repair but this also increases the risk of dysplastic changes due to chromosomal and microsatellite instability. Multiple pathways have been identified, regulated by many positive and negative factors involved in the development of cancer, which in this case follows the ‘inflammation-dysplasia-carcinoma’ sequence. Strategies to lower this risk are extremely important to reduce morbidity and mortality due to IBD-CRC, among which colonoscopic surveillance is the most widely accepted and implemented modality, forming part of many national and international guidelines. However, the effectiveness of surveillance in IBD has been a topic of much debate in recent years for multiple reasons — cost-benefit to health systems, resource requirements, and also because of studies showing conflicting long-term data. Our review provides a comprehensive overview of past, present, and future perspectives of IBD-CRC. We explore and analyse evidence from studies over decades and current best practices followed globally. In the future directions section, we cover emerging novel endoscopic techniques and artificial intelligence that could play an important role in managing the risk of IBD-CRC.

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

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

Shikonin suppresses colon cancer cell growth and exerts synergistic effects by regulating ADAM17 and the IL‑6/STAT3 signaling pathway

Signal transducer and activator of transcription 3 (STAT3) activation is associated with drug resistance induced by anti-epidermal growth factor receptor (anti-EGFR) therapy in the treatment of colon cancer. Thus, the combined inhibition of EGFR and STAT3 may prove beneficial for this type of cancer. STAT3 has been proven to play a critical role in colon cancer initiation and progression, and is considered the primary downstream effector driven by interleukin-6 (IL-6). A disintegrin and metalloproteinase 17 (ADAM17), documented as an oncogene, catalyzes the cleavage of both EGF and IL-6R, inducing EGFR signaling and enabling IL-6 trans-signaling to activate STAT3 in a wide range of cell types to promote inflammation and cancer development. As a natural product, shikonin (SKN) has been found to function as an antitumor agent; however, its role in the regulation of ADAM17 and IL-6/STAT3 signaling in colon cancer cells remains unknown. In the present study, it was found that SKN inhibited colon cancer cell growth, suppressed both constitutive and IL-6-induced STAT3 phosphorylation, and downregulated the expression of ADAM17. ADAM17 expression was not altered in response to STAT3 knockdown, while IL-6-induced STAT3 activation did not induce ADAM17 transcripts. Furthermore, it was demonstrated that SKN did not affect the expression of key proteins involved in the maturation and degradation of ADAM17. SKN decreased ADAM17 expression possibly through reactive oxygen species (ROS)-mediated translational inhibition, as evidenced by the increased ADAM17 mRNA and phosphorylation levels of eukaryotic initiation factor 2α (eIF2α). The expression of ADAM17 and p-eIF2α was reversed by N-acetylcysteine (NAC, a ROS scavenger). Taken together, these results indicate that the concurrent inhibition of ADAM17 and IL-6/STAT3 signaling by SKN may synergistically contribute to the suppression of colon cancer cell growth.

SLCO1B3 promotes colorectal cancer tumorigenesis and metastasis through STAT3

Solute carrier organic anion transporter family member 1B3 (SLCO1B3) is a gene that encodes an organic anion-transporting polypeptide (OATP) 1B3, a membrane-bound multi-specific transporter in hepatocytes. SLCO1B3 was first reported in hepatocytes. Later, it was found that its expression is higher in colorectal cancer (CRC) than in the adjacent normal tissue. However, the role of SLCO1B3 in CRC is not well elucidated. In this study, the correlation between SLCO1B3 and the overall survival (OS) of CRC patients was evaluated using data from the GEO database. This study evaluated the relationship between SLCO1B3 and the clinicopathological characteristics and prognosis of CRC patients. The effects of SLCO1B3 knockdown, on human CRC cell proliferation, migration, and invasion in vitro and CRC tumorigenesis and metastasis in vivo were also examined. In addition, next-generation sequencing was used to identify SLCO1B3 mediators. The results confirmed the association between SLCO1B3 and poor OS of CRC patients, and SLCO1B3 was identified as the top hub gene associated with the OS. The study showed that high SLCO1B3 expression was associated with poor tumor differentiation, advanced disease stage, tumor invasion, lymph node metastasis, and poor OS. Next-generation sequencing revealed that SLCO1B3 knockdown affected the expression of several genes involved in cancer invasion, metastasis, and DNA repair. Moreover, the western blot analysis showed that SLCO1B3 knockdown downregulated p-STAT3, MMP-2, and MMP-9. In summary, we demonstrated that SLCO1B3 acts as a novel carcinogen in the CRC that drives the CRC tumorigenesis and metastasis. SLCO1B3 inhibitors, alone or in combination with current drugs, may have therapeutic benefits in CRC.

Obesity and inflammation: colorectal cancer engines

The prevalence of obesity continues to increase to the extent that it became a worldwide pandemic. An accumulating body of evidence has associated obesity with the development of different types of cancer, including colorectal cancer, which is a notorious disease with a high mortality rate. At the molecular level, colorectal cancer is a heterogenous disease characterized by a myriad of genetic and epigenetic alterations associated with various forms of genomic instability (detailed in Supplementary Materials). Recently, the microenvironment has emerged as a major factor in carcinogenesis. Our aim is to define the different molecular alterations leading to the development of colorectal cancer in obese patients with a focus on the role of the microenvironment in carcinogenesis. We also highlight all existent molecules in clinical trials that target the activated pathways in obesity-associated colorectal cancer, whether used as single treatments or in combination. Obesity predisposes to colorectal cancer via creating a state of chronic inflammation with dysregulated adipokines, inflammatory mediators, and other factors such as immune cell infiltration. A unifying theme in obesity-mediated colorectal cancer is the activation of the PI3K/AKT, mTOR/MAPK, and STAT3 signaling pathways. Different inhibitory molecules towards these pathways exist, increasing the therapeutic choice of obesity-associated colon cancer. However, obese patients are more likely to suffer from chemotherapy overdosing. Preventing obesity through maintaining a healthy and active lifestyle remains to be the best remedy.

Mechanisms involved in selecting and maintaining neuroblastoma cancer stem cell populations, and perspectives for therapeutic targeting

Pediatric neuroblastomas (NBs) are heterogeneous, aggressive, therapy-resistant embryonal tumours that originate from cells of neural crest (NC) origin and in particular neuroblasts committed to the sympathoadrenal progenitor cell lineage. Therapeutic resistance, post-therapeutic relapse and subsequent metastatic NB progression are driven primarily by cancer stem cell (CSC)-like subpopulations, which through their self-renewing capacity, intermittent and slow cell cycles, drug-resistant and reversibly adaptive plastic phenotypes, represent the most important obstacle to improving therapeutic outcomes in unfavourable NBs. In this review, dedicated to NB CSCs and the prospects for their therapeutic eradication, we initiate with brief descriptions of the unique transient vertebrate embryonic NC structure and salient molecular protagonists involved NC induction, specification, epithelial to mesenchymal transition and migratory behaviour, in order to familiarise the reader with the embryonic cellular and molecular origins and background to NB. We follow this by introducing NB and the potential NC-derived stem/progenitor cell origins of NBs, before providing a comprehensive review of the salient molecules, signalling pathways, mechanisms, tumour microenvironmental and therapeutic conditions involved in promoting, selecting and maintaining NB CSC subpopulations, and that underpin their therapy-resistant, self-renewing metastatic behaviour. Finally, we review potential therapeutic strategies and future prospects for targeting and eradication of these bastions of NB therapeutic resistance, post-therapeutic relapse and metastatic progression.

Leukemia inhibitory factor is involved in the pathogenesis of NSCLC through activation of the STAT3 signaling pathway

Leukemia inhibitory factor (LIF) is a tumor promoter in several cancer types. However, the role of LIF in non-small cell lung cancer (NSCLC) remains to be explored. The present study explored the hypothesis that LIF is important for NSCLC development by measuring LIF expression and its downstream signal transducer and activator of transcription 3 (STAT3) phosphorylation in tumor samples derived from patients with NSCLC. The association between LIF expression and clinical features was analyzed in two cancer subtypes. The effects of LIF on cell proliferation, migration and invasion were also evaluated in a NSCLC-derived cell line, A549. LIF mRNA and protein expression levels were significantly higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues. Regarding NSCLC subtypes, LIF expression was significantly higher in adenocarcinoma than in squamous cell carcinoma tissues. It was also found that phosphorylated-STAT3 levels were higher in tumor tissues compared with those in the corresponding adjacent and normal lung tissues, which was in agreement with the LIF expression levels in NSCLC tissues. Clinically, overexpression of LIF was positively correlated with aggressive tumor characteristics, including lymph node metastasis and advanced tumor stage. In A549 cells, LIF treatment enhanced cell proliferation, migration and invasion. LIF also increased STAT3 phosphorylation in A549 cells, and the STAT3 inhibitor Stattic decreased A549 cell migration and invasion following LIF stimulation. The present results demonstrate that LIF is overexpressed in NSCLC, and that LIF can promote NSCLC development through activation of the STAT3 signaling pathway. The present study indicates that LIF may serve as a potential prognostic marker for NSCLC.

Boman B. Retinoids in Treatment of Colorectal Cancer

Retinoids are vitamin A metabolites best known for their role in embryonic development. Indeed, retinoid acid (RA) signaling plays a key role in regulating the development of the embryo body-plan by controlling embryonic stem cells (SCs). Retinoids function through their ability to induce cellular differentiation. Mutations in RA signaling pathway genes occur in most human cancers. The classic example is the chromosomal translocation involving RA receptor alpha in acute promyelocytic leukemia (APL). Because all-trans retinoic acid (ATRA) is a highly effective and often curative treatment for APL patients, determining if retinoids are efficacious for other cancer types is imperative. We review the current research on retinoids in colorectal cancer (CRC) and provide bioinformatics analyses of RA signaling. Our results show that most RA pathway genes are overexpressed and often mutated in CRC. Moreover, aberrant expression of many RA signaling proteins predicts decreased CRC patient survival. We also review aldehyde dehydrogenase (ALDH) expression in CRC because ALDH is a key enzyme in RA signaling, which regulates colonic SCs. Further investigation of RA signaling mechanisms that regulate colon SCs and how dysregulation contributes to the SC overpopulation that drives CRC growth should provide insight into strategies for designing new SC-targeted therapies for CRC.

Stat3 loss in mesenchymal progenitors causes Job syndrome-like skeletal defects by reducing Wnt/β-catenin signaling

Job syndrome is a rare genetic disorder caused by STAT3 mutations and primarily characterized by immune dysfunction along with comorbid skeleton developmental abnormalities including osteopenia, recurrent fracture of long bones, and scoliosis. So far, there is no definitive cure for the skeletal defects in Job syndrome, and treatments are limited to management of clinical symptoms only. Here, we have investigated the molecular mechanism whereby Stat3 regulates skeletal development and osteoblast differentiation. We showed that removing Stat3 function in the developing limb mesenchyme or osteoprogenitor cells in mice resulted in shortened and bow limbs with multiple fractures in long bones that resembled the skeleton symptoms in the Job Syndrome. However, Stat3 loss did not alter chondrocyte differentiation and hypertrophy in embryonic development, while osteoblast differentiation was severely reduced. Genome-wide transcriptome analyses as well as biochemical and histological studies showed that Stat3 loss resulted in down-regulation of Wnt/β-catenin signaling. Restoration of Wnt/β-catenin signaling by injecting BIO, a small molecule inhibitor of GSK3, or crossing with a Lrp5 gain of function (GOF) allele, rescued the bone reduction phenotypes due to Stat3 loss to a great extent. These studies uncover the essential functions of Stat3 in maintaining Wnt/β-catenin signaling in early mesenchymal or osteoprogenitor cells and provide evidence that bone defects in the Job Syndrome are likely caused by Wnt/β-catenin signaling reduction due to reduced STAT3 activities in bone development. Enhancing Wnt/β-catenin signaling could be a therapeutic approach to reduce bone symptoms of Job syndrome patients.

Correlation of IL-6 and JAK2/STAT3 signaling pathway with prognosis of nasopharyngeal carcinoma patients

IL-6 is reported to be the main upstream activator, instead of the downstream target of JAK2/STAT3. This study is intended to explore the correlation of IL-6 and JAK2/STAT3 signaling pathway with clinicopathological features and prognosis in nasopharyngeal carcinoma (NPC). First, NPC tissues and normal nasopharyngeal epithelial tissues were obtained from 117 NPC patients. Next, we detected expression levels of IL-6 in serum and those of STAT3, p-STAT3, JAK2, p-JAK2 and CyclinD1 in tissues. A follow-up was conducted in all the patients and the survival was analyzed. To verify the correlation of IL-6 and JAK2/STAT3 pathway, CNE-1 and SUNE1 NPC cells were interpreted with IL-6 and JAK2/STAT3 signaling pathway inhibitor AG490 to detect cell viability, migration and invasion. We observed thatIL-6 increased in serum of NPC patients. The expressions of IL-6, STAT3, p-STAT3, JAK2, p-JAK2 and CyclinD1 in NPC tissues were higher and correlated with TNM stage and lymph node metastasis (LNM). Survival rates were reduced in patients with positive expressions of IL-6, STAT3, p-STAT3, JAK2, p-JAK2 and CyclinD1. LNM and positive expressions of IL-6 and p-STAT3 were risk factors for poor prognosis of NPC. Besides, recombinant human IL-6 promoted cell proliferation, invasion and migration while AG490 inhibited cell proliferation, invasion and migration in CNE-1 and SUNE1 NPC cells. The results demonstrated that increased IL-6 expression and the activated JAK2/STAT3 signaling pathway had effects on prognosis and reduced the survival time in NPC patients, which provide a potential target for the treatment of NPC.

The Gain-of-Function p53 R248W Mutant Promotes Migration by STAT3 Deregulation in Human Pancreatic Cancer Cells

Missense p53 mutations (mutp53) occur in approx. 70% of pancreatic ductal adenocarcinomas (PDAC). Typically, mutp53 proteins are aberrantly stabilized by Hsp90/Hsp70/Hsp40 chaperone complexes. Notably, stabilization is a precondition for specific mutp53 alleles to acquire powerful neomorphic oncogenic gain-of-functions (GOFs) that promote tumor progression in solid cancers mainly by increasing invasion and metastasis. In colorectal cancer (CRC), we recently established that the common hotspot mutants mutp53^R248Q and mutp53^R248W exert GOF activities by constitutively binding to and hyperactivating STAT3. This results in increased proliferation and invasion in an autochthonous CRC mouse model and correlates with poor survival in patients. Comparing a panel of p53 missense mutations in a series of homozygous human PDAC cell lines, we show here that, similar to CRC, the mutp53^R248W protein again undergoes a strong Hsp90-mediated stabilization and selectively promotes migration. Highly stabilized mutp53 is degradable by the Hsp90 inhibitors Onalespib and Ganetespib, and correlates with growth suppression, possibly suggesting therapeutic vulnerabilities to target GOF mutp53 proteins in PDAC. In response to mutp53 depletion, only mutp53^R248W harboring PDAC cells show STAT3 de-phosphorylation and reduced migration, again suggesting an allele-specific GOF in this cancer entity, similar to CRC. Moreover, mutp53^R248W also exhibits the strongest constitutive complex formation with phosphorylated STAT3. The selective mutp53^R248W GOF signals through enhancing the STAT3 axis, which was confirmed since targeting STAT3 by knockdown or pharmacological inhibition phenocopied mutp53 depletion and reduced cell viability and migration preferentially in mutp53^R248W-containing PDAC cells. Our results confirm that mutp53 GOF activities are allele specific and can span across tumor entities.

Sinomenine Suppresses Development of Hepatocellular Carcinoma Cells via Inhibiting MARCH1 and AMPK/STAT3 Signaling Pathway

Promotion of apoptosis and suppression of proliferation in tumor cells are popular strategies for developing anticancer drugs. Sinomenine (SIN), a plant-derived alkaloid, displays antitumor activity. However, the mechanism of action of SIN against hepatocellular carcinoma (HCC) is unclear. Herein, several molecular technologies, such as Western Blotting, qRT-PCR, flow cytometry, and gene knockdown were applied to explore the role and mechanism of action of SIN in the treatment of HCC. It was found that SIN arrests HCC cell cycle at G0/G1 phase, induces apoptosis, and suppresses proliferation of HCC cells via down-regulating the expression of membrane-associated RING-CH finger protein 1 (MARCH1). Moreover, SIN induces cell death and growth inhibition through AMPK/STAT3 signaling pathway. MARCH1 expression was silenced by siRNA to explore its involvement in the regulation of AMPK/STAT3 signaling pathway. Silencing MARCH1 caused down-regulation of phosphorylation of AMPK, STAT3 and decreased cell viability and function. Our results suggested that SIN inhibits proliferation and promotes apoptosis of HCC cells by MARCH1-mediated AMPK/STAT3 signaling pathway. This study provides new support for SIN as a clinical anticancer drug and illustrates that targeting MARCH1 could be a novel treatment strategy in developing anticancer therapeutics.

Redox responsive Pluronic micelle mediated delivery of functional siRNA: a modular nano-assembly for targeted delivery

There is an unmet need to develop strategies that allow site-specific delivery of short interfering RNA (siRNA) without any associated toxicity. To address this challenge, we have developed a novel siRNA delivery platform using chemically modified pluronic F108 as an amphiphilic polymer with a releasable bioactive disulfide functionality. The micelles exhibited thermoresponsive properties and showed a hydrodynamic size of ∼291 nm in DLS and ∼200-250 nm in SEM at 37 °C. The grafting of free disulfide pyridyl groups enhanced the transfection efficiency and was successfully demonstrated in human colon carcinoma (HCT116; 88%) and glioma cell lines (U87; 90%), non-cancerous human dermal fibroblast (HDF; 90%) cells as well as in mouse embryonic stem (mES; 54%) cells. To demonstrate the versatility of our modular nanocarrier design, we conjugated the MDGI receptor targeting COOP peptide on the particle surface that allowed the targeted delivery of the cargo molecules to human patent-derived primary BT-13 gliospheres. Transfection experiments with this design resulted in ∼65% silencing of STAT3 mRNA in BT-13 gliospheres, while only ∼20% of gene silencing was observed in the absence of the peptide. We believe that our delivery method solves current problems related to the targeted delivery of RNAi drugs for potential in vivo applications.

The stabilization of yes-associated protein by TGFβ-activated kinase 1 regulates the self-renewal and oncogenesis of gastric cancer stem cells

Gastric cancer (GC) is the most frequent digestive system malignant tumour and the second most common cause of cancer death globally. Cancer stem cell (CSC) is a small percentage of cancer cells in solid tumours that have differentiation, self‐renewal and tumorigenic capabilities. They have an active participation in the initiation, development, metastasis, recurrence and resistance of tumours to chemotherapy and radiotherapy. Gastric cancer stem cells (GCSCs) have been shown to be correlated with GC initiation and metastasis. In this study, we found that TAK1 expression level in GC tissues was significantly increased compared to the adjacent non‐cancerous tissues by RT‐qPCR, Western blot and immunohistochemistry. TAK1 has been identified as a critical molecule that promoted a variety of malignant GC phenotypes both in vivo and in vitro and promoted the self‐renewal of GCSCs. Mechanistically, TAK1 was up‐regulated by IL‐6 and prevented the degradation of yes‐associated protein (YAP) in the cytoplasm by binding to YAP. Thus, TAK1 promoted the SOX2 and SOX9 transcription and the self‐renewal and oncogenesis of GCSCs. Our findings provide insights into the mechanism of self‐renewal and tumorigenesis of TAK1 in GCSCs and have broad implications for clinical therapies.

Salidroside induces cell apoptosis and inhibits the invasiveness of HT29 colorectal cells by regulating protein kinase R, NF-κB and STAT3

BACKGROUND

Protein kinase R (PKR) can suppress various types of solid tumors by inducing cellular oxidative stress and apoptosis. Likewise, Slaidorside, a plant flavonoid, was shown to have anti-tumorigenesis in many solid tumors.

OBJECTIVE

This study evaluated anti-tumorigenesis of Salidroside in HT29 colorectal cancer and investigated if the underlying mechanism involves activation of PKR.

METHODS

Control or PKR deficient cells were cultured in DMEM media treated with 100 μM Salidroside and cell survival, apoptosis, and other biochemical-related markers were evaluated.

RESULTS

Salidroside significantly reduced cell survival and proliferation and increased the release of lactate dehydrogenase (LDH) and levels of single-stranded DNA (ssDNA). It also increased the protein levels of caspases 3 and 8. Concomitantly, Salidroside increased the protein level and activity of PKR and increased the expression of its downstream targets, p-eIF2α (Ser51), p53 MAPK, and p53. On the contrary, it inhibited the nuclear activation of STAT-3 and NF-κB p65. In PKR deficient cells, the partial effects of Salidroside on cell survival, proliferation, and apoptotic markers were observed coincided with no effects on the expression of eIF-2α, and JNK, p53, p38 MAPK, and caspase 8 but with a significant decrease in the nuclear activities of STAT3 and NF-κB.

CONCLUSION

Salidroside suppresses the tumorigenesis of HT29 CRC by increasing activation of eIF-2α and JNK and upregulation of p53, p38 MAPK, and caspase-8 through upregulating and activation of PKR. However, the tumor suppressor effect of Salidroside requires also inhibition of STAT3 and NF-κB in a PKR-independent mechanism.

Lessons to Learn for Adequate Targeted Therapy Development in Metastatic Colorectal Cancer Patients

Insulin-like growth factor 1 receptor (IGF1R) is a receptor tyrosine kinase that regulates cell growth and proliferation. Upregulation of the IGF1R pathway constitutes a common paradigm shared with other receptor tyrosine kinases such as EGFR, HER2, and MET in different cancer types, including colon cancer. The main IGF1R signaling pathways are PI3K-AKT and MAPK-MEK. However, different processes, such as post-translational modification (SUMOylation), epithelial-to-mesenchymal transition (EMT), and microenvironment complexity, can also contribute to intrinsic and acquired resistance. Here, we discuss new strategies for adequate drug development in metastatic colorectal cancer patients.

RFX1: a promising therapeutic arsenal against cancer

Regulatory factor X1 (RFX1) is an evolutionary conserved transcriptional factor that influences a wide range of cellular processes such as cell cycle, cell proliferation, differentiation, and apoptosis, by regulating a number of target genes that are involved in such processes. On a closer look, these target genes also play a key role in tumorigenesis and associated events. Such observations paved the way for further studies evaluating the role of RFX1 in cancer. These studies were indispensable due to the failure of conventional chemotherapeutic drugs to target key cellular hallmarks such as cancer stemness, cellular plasticity, enhanced drug efflux, de-regulated DNA repair machinery, and altered pathways evading apoptosis. In this review, we compile significant evidence for the tumor-suppressive activities of RFX1 while also analyzing its oncogenic potential in some cancers. RFX1 induction decreased cellular proliferation, modulated the immune system, induced apoptosis, reduced chemoresistance, and sensitized cancer stem cells for chemotherapy. Thus, our review discusses the pleiotropic function of RFX1 in multitudinous gene regulations, decisive protein–protein interactions, and also its role in regulating key cell signaling events in cancer. Elucidation of these regulatory mechanisms can be further utilized for RFX1 targeted therapy.

Construction of an immune-related signature with prognostic value for colon cancer

BACKGROUND

Colon cancer is the third most common malignant tumor in the world. Although immunotherapy has been used in cancer treatment, there is still no first-line immunotherapy method for colon cancer. Therefore, it is essential to search for potential immunotherapy targets and molecular biomarkers for early diagnosis and prognosis.

METHODS

In this study, we downloaded transcriptome data from The Cancer Genome Atlas (TCGA) and immune-related genes from the ImmPort database. Then we filtered genes with prognostic value and constructed an immune-related signature. Patients were classified into low- and high-risk groups, and we exerted a series of analysis between the signature and clinical phenotypes. Additionally, we used protein-protein interaction networks, gene set enrichment analysis (GSEA) and single-sample gene-set enrichment analysis (ssGSEA) to explore the underlying mechanism of this signature. Furthermore, the accuracy of this signature was verified, using two data sets from Gene Expression Omnibus (GEO).

RESULTS

We selected 12 immune-related genes to construct the immune-related signature. Low-risk group had a higher level of immunity compared to high-risk group. The expression level of HLA genes and checkpoint-related genes were statistically different in low- and high-risk groups. This signature showed its prognostic value in TCGA cohort and 2 GEO data sets. The signature also had strong correlation with TNM classification, stage, survival state and lymphatic invasion. The mechanism of the signature may be related to several transcription factors and CD8+ T cell in the tumor microenvironment.

CONCLUSION

In conclusion, this immune-related signature is of great prognosis value for colon cancer and its biofunction might be correlated with HLA genes, checkpoint-related genes and high-infiltrating T cells in tumor tissues.

Targeting key transcriptional factor STAT3 in colorectal cancer

In developed countries, colorectal cancer (CRC) is the fourth most common cancer and the second leading cause of malignant-related deaths. CRC is treatable cancer when diagnosed early; however, diagnosis at the advanced stage is associated with a poor prognosis. Although chemotherapy is generally very promising, STAT3 protein which is overexpressed and persistently activated in CRC cells is observed to be the major contributor of chemoresistance development. It has been shown to play a prominent and pathogenic role in CRC initiation, progression, and metastasis. While over the past few years, research has been focused on STAT3 which is expressed at the center of various oncogenic pathways. This review is a discussion of the oncogenic role of STAT3 in CRC and potential therapeutic STAT3 inhibitors and analogs used to control and treat CRC.

MicroRNA-124-3p suppresses PD-L1 expression and inhibits tumorigenesis of colorectal cancer cells via modulating STAT3 signaling

Programmed death ligand 1 (PD-L1) plays a significant role in colorectal tumorigenesis through induction of regulatory T cells (Tregs) and suppression of antitumor immunity. Furthermore, microRNAs (miRNAs) as the posttranscriptional regulators of gene expression show considerable promise as a therapeutic target for colorectal cancer (CRC) treatment. Considering this, in vitro effects of miRNA-124 (miR-124-3p) on CRC cell tumorigenesis and Tregs differentiation via targeting PD-L1 were investigated in the current study. Functional analysis showed that miR-124 is significantly downregulated in CRC tissues as compared with marginal normal samples (p < .0001), and its downregulation was negatively correlated with PD-L1 expression. Moreover, a specific region in PD-L1 3'-untranslated region was predicted as the miR-124 target and validated using the luciferase assay. Further investigation showed that transfection of HT29 and SW480 cells with miR-124 mimics significantly reduced PD-L1 mRNA, protein, and cell surface expression, and inhibited Tregs in coculture models via modulating interleukin [IL]-10, IL-2, tumor necrosis factor α, transforming growth factor beta, and interferon gamma expression levels. Besides, miR-124 overexpression decreased CRC cell proliferation and arrested cell cycle at the G1 phase through downregulation of c-Myc and induced apoptosis in CRC cells via upregulation of both intrinsic and extrinsic pathways. Also, miR-124 exogenous overexpression could reduce colony and spheroid formation ability of CRC cells via downregulating CD44 mRNA expression. miR-124 also diminished MMP-9 expression and subsequently suppressed cell migration and invasion. We also illustrated that STAT3 signaling was repressed by miR-124 in CRC cells. Taken together, our findings imply that considering the involvement of miR-124 in the regulation of PD-L1 through colorectal tumorigenesis and its remarkable antitumor effects, this miRNA could be regarded as the promising target for the development of therapeutic approaches for colorectal cancer.