Activation of STAT3 and STAT5 Signaling in Epithelial Ovarian Cancer Progression: Mechanism and Therapeutic Opportunity

Selective targeting of IRAK1 attenuates low molecular weight hyaluronic acid-induced stemness and non-canonical STAT3 activation in epithelial ovarian cancer

Advanced epithelial ovarian cancer (EOC) survival rates are dishearteningly low, with ~25% surviving beyond 5 years. Evidence suggests that cancer stem cells contribute to acquired chemoresistance and tumor recurrence. Here, we show that IRAK1 is upregulated in EOC tissues, and enhanced expression correlates with poorer overall survival. Moreover, low molecular weight hyaluronic acid, which is abundant in malignant ascites from patients with advanced EOC, induced IRAK1 phosphorylation leading to STAT3 activation and enhanced spheroid formation. Knockdown of IRAK1 impaired tumor growth in peritoneal disease models, and impaired HA-induced spheroid growth and STAT3 phosphorylation. Finally, we determined that TCS2210, a known inducer of neuronal differentiation in mesenchymal stem cells, is a selective inhibitor of IRAK1. TCS2210 significantly inhibited EOC growth in vitro and in vivo both as monotherapy, and in combination with cisplatin. Collectively, these data demonstrate IRAK1 as a druggable target for EOC.

PAX6 promotes neuroendocrine phenotypes of prostate cancer via enhancing MET/STAT5A-mediated chromatin accessibility

BACKGROUND

Neuroendocrine prostate cancer (NEPC) is a lethal subset of prostate cancer which is characterized by neuroendocrine differentiation and loss of androgen receptor (AR) signaling. Growing evidence reveals that cell lineage plasticity is crucial in the failure of NEPC therapies. Although studies suggest the involvement of the neural transcription factor PAX6 in drug resistance, its specific role in NEPC remains unclear.

METHODS

The expression of PAX6 in NEPC was identified via bioinformatics and immunohistochemistry. CCK8 assay, colony formation assay, tumorsphere formation assay and apoptosis assay were used to illustrate the key role of PAX6 in the progression of in vitro. ChIP and Dual-luciferase reporter assays were conducted to confirm the binding sequences of AR in the promoter region of PAX6, as well as the binding sequences of PAX6 in the promoter regions of STAT5A and MET. For in vivo validation, the xenograft model representing NEPC subtype underwent pathological analysis to verify the significant role of PAX6 in disease progression. Complementary diagnoses were established through public clinical datasets and transcriptome sequencing of specific cell lines. ATAC-seq was used to detect the chromatin accessibility of specific cell lines.

RESULTS

PAX6 expression was significantly elevated in NEPC and negatively regulated by AR signaling. Activation of PAX6 in non-NEPC cells led to NE trans-differentiation, while knock-down of PAX6 in NEPC cells inhibited the development and progression of NEPC. Importantly, loss of AR resulted in an enhanced expression of PAX6, which reprogramed the lineage plasticity of prostate cancer cells to develop NE phenotypes through the MET/STAT5A signaling pathway. Through ATAC-seq, we found that a high expression level of PAX6 elicited enhanced chromatin accessibility, mainly through attenuation of H4K20me3, which typically causes chromatin silence in cancer cells.

CONCLUSION

This study reveals a novel neural transcription factor PAX6 could drive NEPC progression and suggest that it might serve as a potential therapeutic target for the management of NEPC.

STAT5a and SH2B3 novel mutations display malignancy roles in a triple-negative primary myelofibrosis patient

Primary myelofibrosis (PMF) patients frequently have JAK2 (V617F), CALR (exon 9), or MPL (W515 or exon 10) strong driver gene mutation, which triggers abnormal activation of the JAK2-STATs signaling pathway that plays a complex role in the occurrence of PMF. However, about 10-15% of PMF patients have no above typical mutations in these strong driver genes, known as being "triple-negative", which are associated with poor prognosis. In this paper, we reported a unique secondary acute myeloid leukemia (sAML) case transformed from triple-negative PMF combined with lung cancer and erythroderma occurrence at the same time, which has not been reported so far. Through whole blood exome sequencing, four novel noncanonical mutations were detected in key regulatory genes SH2B3 (Q748 and S710) and STAT5a (C350 and K354). Meanwhile, STAT5a-S710 and SH2B3-K354 noncanonical mutations gained strong malignant biofunction on promoting cell growth and tumorigenesis by accelerating the G1/S transition. In the mechanistic study, these pernicious phenotypes driven by noncanonical mutations might be initial PMF by activating p-STAT5a/c-Myc/CyclinD1 and p-STAT3/p-AKT/p-ERK1/2 signaling axes. Therefore, our study explored the deleterious roles of novel noncanonical mutations in STAT5a and SH2B3, which may serve as susceptibility genes and display the oncogenic biofunction in the progression of PMF to acute myeloid leukemia-M2a (AML-M2a).

Research progress on traditional Chinese medicine-induced apoptosis signaling pathways in ovarian cancer cells

ETHNOPHARMACOLOGICAL RELEVANCE

As a "silent killer" that threatens women's lives and health, ovarian cancer (OC) has the clinical characteristics of being difficult to detect, difficult to treat, and high recurrence. Traditional Chinese medicine (TCM) can be utilized as a long-term complementary and alternative therapy since it has shown benefits in alleviating clinical symptoms of OC, decreasing toxic side effects of radiation and chemotherapy, as well as enhancing patients' quality of life.

AIM OF THE REVIEW

This paper reviews how TCM contributes to the apoptosis of OC cells through signaling pathways, including active constituents, extracts, and herbal formulas, with the aim of providing a basis for the development and clinical application of therapeutic strategies for TCM in OC.

METHODS

The search was conducted from scientific databases PubMed, Embase, Web of Science, CNKI, Wanfang, VIP, and SinoMed databases aiming to elucidate the apoptosis signaling pathways in OC cells by TCM. The articles were searched by the keywords "ovarian cancer", "apoptosis", "signaling pathway", "traditional Chinese medicine", "Chinese herbal monomer", "Chinese herbal extract", and "herbal formula". The search was conducted from January 2013 to June 2023. A total of 97 potentially relevant articles were included, including 93 articles on Chinese medicine active constituents or extracts and 4 articles on Chinese herbal compound prescriptions.

RESULTS

TCM can induce apoptosis in OC cells by regulating signaling pathways with obvious advantages, including STAT3, PI3K/AKT, Wnt/β-catenin, MAPK, NF-κB, Nrf2, HIF-1α, Fas/Fas L signaling pathway, etc. CONCLUSION: Chinese medicine can induce apoptosis in OC cells through multiple pathways, targets, and routes. TCM has special advantages for treating OC, providing more reasonable evidence for the research and development of new apoptosis inducers.

Prediction of Chemoresistance-How Preclinical Data Could Help to Modify Therapeutic Strategy in High-Grade Serous Ovarian Cancer

High-grade serous ovarian cancer (HGSOC) is one of the most lethal tumors generally and the most fatal cancer of the female genital tract. The approved standard therapy consists of surgical cytoreduction and platinum/taxane-based chemotherapy, and of targeted therapy in selected patients. The main therapeutic problem is chemoresistance of recurrent and metastatic HGSOC tumors which results in low survival in the group of FIGO III/IV. Therefore, the prediction and monitoring of chemoresistance seems to be of utmost importance for the improvement of HGSOC management. This type of cancer has genetic heterogeneity with several subtypes being characterized by diverse gene signatures and disturbed peculiar epigenetic regulation. HGSOC develops and metastasizes preferentially in the specific intraperitoneal environment composed mainly of fibroblasts, adipocytes, and immune cells. Different HGSOC subtypes could be sensitive to distinct sets of drugs. Moreover, primary, metastatic, and recurrent tumors are characterized by an individual biology, and thus diverse drug responsibility. Without a precise identification of the tumor and its microenvironment, effective treatment seems to be elusive. This paper reviews tumor-derived genomic, mutational, cellular, and epigenetic biomarkers of HGSOC drug resistance, as well as tumor microenvironment-derived biomarkers of chemoresistance, and discusses their possible use in the novel complex approach to ovarian cancer therapy and monitoring.

Interplay between signal transducers and activators of transcription (STAT) proteins and cancer: involvement, therapeutic and prognostic perspective

Signal transducers and activators of transcription or STAT are proteins that consist of various transcription factors that are responsible for activating genes regarding cell proliferation, differentiation, and apoptosis. They commonly activate several cytokine, growth, or hormone factors via the JAK-STAT signaling pathway by tyrosine phosphorylation which are responsible for giving rise to numerous immune responses. Mutations within the Janus-Kinases (JAKs) or the STATs can set off the commencement of various malfunctions of the immune system of the body; carcinogenesis being an inevitable outcome. STATs are known to act as both oncogenes and tumor suppressor genes which makes it a hot topic of investigation. Various STATs related mechanisms are currently being investigated to analyze its potential of serving as a therapeutic base for numerous immune diseases and cancer; a deeper understanding of the molecular mechanisms involved in the signaling pathways can contribute to the same. This review will throw light upon each STAT member in causing cancer malignancies by affecting subsequent signaling pathways and its genetic and epigenetic associations as well as various inhibitors that could be used to target these pathways thereby devising new treatment options. The review will also focus upon the therapeutic advances made in cancers that most commonly affect people and discuss how STAT genes are identified as prognostic markers.

Monotropein inhibits colitis associated cancer through VDR/JAK1/STAT1 regulation of macrophage polarization

Colorectal cancer (CRC) is a growing concern due to its high morbidity and mortality, and the search for effective and less toxic active substances against inflammatory bowel diseases has been a hot topic in the research and development of drugs against CRC. It is reported that monotropein isolated from the roots of Morinda officinalis, can improve Dextran Sodium Sulfate (DSS)-induced ulcerative colitis in mice, but its therapeutic effects and mechanisms for CRC treatment are still to be investigated. In the present study, we first used molecular docking, BLI, CESTA, and DARTS methods to detest whether monotropein targets VDR proteins. In addition, we used tumor cell conditioned co-culture and four models of macrophage polarisation to investigate the regulation of four macrophage polarisations by monotropein using RT-PCR, IF and western blot. Furthermore, we further validated the target of action of monotropein for the treatment of Azoxymethane (AOM)/DSS induced colitis associated cancer (CAC) using knockout animals. Meanwhile, we further explored the mechanism of action of monotropein in regulating polarisation by detecting JAK/STAT1-related genes and proteins. Molecular docking and biofilm interference techniques showed that monotropein bound to the VDR, and additional results from CESTA and DARTS suggested that VDR proteins are targets of monotropein. Furthermore, in tumor cell conditioned co-cultures or LPS + IFN-γ induced RAW264.7 cells, VDR translocation to the nucleus was reduced, JAK1/STAT1 signaling pathway proteins were up-regulated, and macrophages were polarised towards the M1-type after monotropein intervention. Animal models in which normal VDR or myeloid VDR was knocked out confirmed that JAK1 levels in intestinal tissues were increased after monotropein intervention, macrophages were polarised towards the M1 type, and CAC paracarcinomas were ameliorated. Taken together, the present study concluded that monotropein inhibited colitis-associated cancers through macrophage polarisation regulated by VDR/JAK1/STAT1.

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Role of STATs in Ovarian Cancer: Exploring Their Potential for Therapy

Ovarian cancer (OvCa) is a deadly gynecologic malignancy that presents many clinical challenges due to late-stage diagnoses and the development of acquired resistance to standard-of-care treatment protocols. There is an increasing body of evidence suggesting that STATs may play a critical role in OvCa progression, resistance, and disease recurrence, and thus we sought to compile a comprehensive review to summarize the current state of knowledge on the topic. We have examined peer reviewed literature to delineate the role of STATs in both cancer cells and cells within the tumor microenvironment. In addition to summarizing the current knowledge of STAT biology in OvCa, we have also examined the capacity of small molecule inhibitor development to target specific STATs and progress toward clinical applications. From our research, the best studied and targeted factors are STAT3 and STAT5, which has resulted in the development of several inhibitors that are under current evaluation in clinical trials. There remain gaps in understanding the role of STAT1, STAT2, STAT4, and STAT6, due to limited reports in the current literature; as such, further studies to establish their implications in OvCa are necessitated. Moreover, due to the deficiency in our understanding of these STATs, selective inhibitors also remain elusive, and therefore present opportunities for discovery.

Disruption of Ovarian Cancer STAT3 and p38 Signaling with a Small-Molecule Inhibitor of PTP4A3 Phosphatase

Protein tyrosine phosphatase type IVA member 3 (PTP4A3 or PRL-3) is a nonreceptor, oncogenic, dual-specificity phosphatase that is highly expressed in many human tumors, including ovarian cancer, and is associated with a poor patient prognosis. Recent studies suggest that PTP4A3 directly dephosphorylates SHP-2 phosphatase as part of a STAT3-PTP4A3 feedforward loop and directly dephosphorylates p38 kinase. The goal of the current study was to examine the effect of a PTP4A phosphatase inhibitor, 7-imino-2-phenylthieno[3,2-c]pyridine-4,6(5H,7H)-dione (JMS-053), on ovarian cancer STAT3, SHP-2, and p38 kinase phosphorylation. JMS-053 caused a concentration- and time-dependent decrease in the activated form of STAT3, Y705 phospho-STAT3, in ovarian cancer cells treated in vitro. In contrast, the phosphorylation status of two previously described direct PTP4A3 substrates, SHP-2 phosphatase and p38 kinase, were rapidly increased with JMS-053 treatment. We generated A2780 and OVCAR4 ovarian cancer cells resistant to JMS-053, and the resulting cells were not crossresistant to paclitaxel, cisplatin, or teniposide. JMS-053-resistant A2780 and OVCAR4 cells exhibited a 95% and 50% decrease in basal Y705 phospho-STAT3, respectively. JMS-053-resistant OVCAR4 cells had an attenuated phosphorylation and migratory response to acute exposure to JMS-053. These results support a regulatory role for PTP4A phosphatase in ovarian cancer cell STAT3 and p38 signaling circuits. SIGNIFICANCE STATEMENT: This study demonstrates that chemical inhibition of PTP4A phosphatase activity with JMS-053 decreases STAT3 activation and increases SHP-2 phosphatase and p38 kinase phosphorylation activation in ovarian cancer cells. The newly developed JMS-053-resistant ovarian cancer cells should provide useful tools to further probe the role of PTP4A phosphatase in ovarian cancer cell survival and cell signaling.

Breast cancer tumor microenvironment affects Treg/IL-17-producing Treg/Th17 cell axis: Molecular and therapeutic perspectives

The tumor microenvironment (TME) comprises a variety of immune cells, among which T cells exert a prominent axial role in tumor development or anti-tumor responses in patients with breast cancer (BC). High or low levels of anti-inflammatory cytokines, such as transforming growth factor β, in the absence or presence of proinflammatory cytokines, such as interleukin-6 (IL-6), delineate the fate of T cells toward either regulatory T (Treg) or T helper 17 (Th17) cells, respectively. The transitional state of RORγt⁺Foxp3⁺ Treg (IL-17-producing Treg) resides in the middle of this reciprocal polarization, which is known as Treg/IL-17-producing Treg/Th17 cell axis. TME secretome, including microRNAs, cytokines, and extracellular vesicles, can significantly affect this axis. Furthermore, immune checkpoint inhibitors may be used to reconstruct immune cells; however, some of these novel therapies may favor tumor development. Therefore, understanding secretory and cell-associated factors involved in their differentiation or polarization and functions may be targeted for BC management. This review discusses microRNAs, cytokines, and extracellular vesicles (as secretome), as well as transcription factors and immune checkpoints (as cell-associated factors), which influence the Treg/IL-17-producing Treg/Th17 cell axis in BC. Furthermore, approved or ongoing clinical trials related to the modulation of this axis in the TME of BC are described to broaden new horizons of promising therapeutic approaches.

NINJ1 triggers extravillous trophoblast cell dysfunction through blocking the STAT3 signaling pathway

BACKGROUND

Trophoblasts are the most important parts of the placenta in early pregnancy. Trophoblast cell dysfunction can induce embryo implantation insufficiency, thereby resulting in multiple diseases, including recurrent spontaneous abortion (RSA). A previous study indicates higher nerve injury-induced protein 1 (NINJ1) RNA levels in the villi tissues of RSA patients.

OBJECTIVE

This study aimed to investigate the effect of NINJ1 on trophoblast behaviors and pregnancy loss.

METHODS

Fresh villi tissues were obtained from with RSA patients and patients with artificial selective abortion for personal reasons, and NINJ1 expression in these tissues was detected. Extravillous trophoblast cell line HTR-8/SVneo was transfected with small-interfering RNA targeting NINJ1 or NINJ1 overexpression vector to perform loss-/gain-of-function experiments. Spontaneous abortion (SA) was induced by mating CBA/J females with DBA/2 males and the pregnant females were intraperitoneally injected with adenovirus vector carrying NINJ1 short hairpin RNA.

RESULTS

NINJ1 mRNA and protein levels were higher in the villi tissues of RSA patients than those of artificial selective abortion patients. NINJ1 knockdown promoted trophoblast cell proliferation, migration and invasion but inhibited cell apoptosis. Moreover, conditioned medium from NINJ1-depleted trophoblasts promoted the angiogenesis of human umbilical vein endothelial cells. NINJ1 knockdown also promoted activation of the signal transducer and activator of transcription 3 (STAT3) signaling pathway in trophoblasts, and STAT3 inhibitor reversed NINJ1 knockdown-induced effects on trophoblast behaviors. Furthermore, pregnancy loss was attenuated by NINJ1 inhibition.

CONCLUSION

NINJ1 contributes to the development of SA and triggers trophoblast cell dysfunction through inhibiting the STAT3 pathway.

BMP2 as a promising anticancer approach: functions and molecular mechanisms

Bone morphogenetic protein 2 (BMP2), a pluripotent factor, is a member of the transforming growth factor-beta (TGF-β) superfamily and is implicated in embryonic development and postnatal homeostasis in tissues and organs. Experimental research in the contexts of physiology and pathology has indicated that BMP2 can induce macrophages to differentiate into osteoclasts and accelerate the osteolytic mechanism, aggravating cancer cell bone metastasis. Emerging studies have stressed the potent regulatory effect of BMP2 in cancer cell differentiation, proliferation, survival, and apoptosis. Complicated signaling networks involving multiple regulatory proteins imply the significant biological functions of BMP2 in cancer. In this review, we comprehensively summarized and discussed the current evidence related to the modulation of BMP2 in tumorigenesis and development, including evidence related to the roles and molecular mechanisms of BMP2 in regulating cancer stem cells (CSCs), epithelial-mesenchymal transition (EMT), cancer angiogenesis and the tumor microenvironment (TME). All these findings suggest that BMP2 may be an effective therapeutic target for cancer and a new marker for assessing treatment efficacy.

Integrated analysis of the M2 macrophage-related signature associated with prognosis in ovarian cancer

Background

M2 macrophages play an important role in cancer development. However, the underlying biological fator affecting M2 macrophages infiltration in ovarian cancer (OV) has not been elucidated.

Methods

R software v 4.0.0 was used for all the analysis. The expression profile and clinical information of OV patients enrolled in this study were all downloaded from The Cancer Genome Atlas and Gene Expression Omnibus databases.

Results

The CIBERSORT algorithm was used to quantify the M2 macrophage infiltration in OV tissue, which was found a risk factor for patients survival. Based on the limma package, a total of 196 DEGs were identified between OV patients with high and low M2 macrophage infiltration, which were defined as M2 macrophages related genes. Finally, the genes PTGFR, LILRA2 and KCNA1 were identified for prognosis model construction, which showed a great prediction efficiency in both training and validation cohorts (Training cohort, 1-year AUC = 0.661, 3-year AUC = 0.682, 8-year AUC = 0.846; Validation cohort, 1-year AUC = 0.642, 3-year AUC = 0.716, 5-year AUC = 0.741). Clinical correlation showed that the riskscore was associated with the worse clinical features. Pathway enrichment analysis showed that in high risk patients, the pathway of epithelial-mesenchymal transition (EMT), TNF-α signaling via NFKB, IL2/STAT5 signaling, apical junction, inflammatory response, KRAS signaling, myogenesis were activated. Moreover, we found that the PTGFR, LILRA2 and KCNA1 were all positively correlated with M2 macrophage infiltration and PTGFR was significantly associated with the pathway of autophagy regulation. Moreover, we found that the low risk patients might be more sensitive to cisplatin, while high risk patient might be more sensitive to axitinib, bexarotene, bortezomib, nilotinib, pazopanib.

Conclusions

In this study, we identified the genes associated with M2 macrophage infiltration and developed a model that could effectively predict the prognosis of OV patients.

Recent research on the association between signal transducer and activator of transcription 5 and childhood acute lymphoblastic leukemia

Signal transducer and activator of transcription 5 (STAT5) can be involved in the processes such as cell proliferation, differentiation, apoptosis, and hematopoiesis, and its dysregulation is closely associated with the development and progression of malignant tumors including leukemia and may affect the treatment outcome and prognosis of pediatric patients. Identification of STAT5 can facilitate targeted therapy to improve the response rate of children with acute lymphoblastic leukemia. This article reviews the impact of STAT5 on the development/progression, targeted therapy strategies and the prognosis of childhood acute lymphoblastic leukemia.

A review of granulocyte colony-stimulating factor receptor signaling and regulation with implications for cancer

Granulocyte colony-stimulating factor receptor (GCSFR) is a critical regulator of granulopoiesis. Studies have shown significant upregulation of GCSFR in a variety of cancers and cell types and have recognized GCSFR as a cytokine receptor capable of influencing both myeloid and non-myeloid immune cells, supporting pro-tumoral actions. This systematic review aims to summarize the available literature examining the mechanisms that control GCSFR signaling, regulation, and surface expression with emphasis on how these mechanisms may be dysregulated in cancer. Experiments with different cancer cell lines from breast cancer, bladder cancer, glioma, and neuroblastoma are used to review the biological function and underlying mechanisms of increased GCSFR expression with emphasis on actions related to tumor proliferation, migration, and metastasis, primarily acting through the JAK/STAT pathway. Evidence is also presented that demonstrates a differential physiological response to aberrant GCSFR signal transduction in different organs. The lifecycle of the receptor is also reviewed to support future work defining how this signaling axis becomes dysregulated in malignancies.

JAK/STAT Signaling: Molecular Targets, Therapeutic Opportunities, and Limitations of Targeted Inhibitions in Solid Malignancies

JAK/STAT signaling pathway is one of the important regulatory signaling cascades for the myriad of cellular processes initiated by various types of ligands such as growth factors, hormones, and cytokines. The physiological processes regulated by JAK/STAT signaling are immune regulation, cell proliferation, cell survival, apoptosis and hematopoiesis of myeloid and non-myeloid cells. Dysregulation of JAK/STAT signaling is reported in various immunological disorders, hematological and other solid malignancies through various oncogenic activation mutations in receptors, downstream mediators, and associated transcriptional factors such as STATs. STATs typically have a dual role when explored in the context of cancer. While several members of the STAT family are involved in malignancies, however, a few members which include STAT3 and STAT5 are linked to tumor initiation and progression. Other STAT members such as STAT1 and STAT2 are pivotal for antitumor defense and maintenance of an effective and long-term immune response through evolutionarily conserved programs. The effects of JAK/STAT signaling and the persistent activation of STATs in tumor cell survival; proliferation and invasion have made the JAK/STAT pathway an ideal target for drug development and cancer therapy. Therefore, understanding the intricate JAK/STAT signaling in the pathogenesis of solid malignancies needs extensive research. A better understanding of the functionally redundant roles of JAKs and STATs may provide a rationale for improving existing cancer therapies which have deleterious effects on normal cells and to identifying novel targets for therapeutic intervention in solid malignancies.

Comparing the Secretomes of Chemorefractory and Chemoresistant Ovarian Cancer Cell Populations

High-grade serous ovarian cancer (HGSOC) constitutes the majority of all ovarian cancer cases and has staggering rates of both refractory and recurrent disease. While most patients respond to the initial treatment with paclitaxel and platinum-based drugs, up to 25% do not, and of the remaining that do, 75% experience disease recurrence within the subsequent two years. Intrinsic resistance in refractory cases is driven by environmental stressors like tumor hypoxia which alter the tumor microenvironment to promote cancer progression and resistance to anticancer drugs. Recurrent disease describes the acquisition of chemoresistance whereby cancer cells survive the initial exposure to chemotherapy and develop adaptations to enhance their chances of surviving subsequent treatments. Of the environmental stressors cancer cells endure, exposure to hypoxia has been identified as a potent trigger and priming agent for the development of chemoresistance. Both in the presence of the stress of hypoxia or the therapeutic stress of chemotherapy, cancer cells manage to cope and develop adaptations which prime populations to survive in future stress. One adaptation is the modification in the secretome. Chemoresistance is associated with translational reprogramming for increased protein synthesis, ribosome biogenesis, and vesicle trafficking. This leads to increased production of soluble proteins and extracellular vesicles (EVs) involved in autocrine and paracrine signaling processes. Numerous studies have demonstrated that these factors are largely altered between the secretomes of chemosensitive and chemoresistant patients. Such factors include cytokines, growth factors, EVs, and EV-encapsulated microRNAs (miRNAs), which serve to induce invasive molecular, biophysical, and chemoresistant phenotypes in neighboring normal and cancer cells. This review examines the modifications in the secretome of distinct chemoresistant ovarian cancer cell populations and specific secreted factors, which may serve as candidate biomarkers for aggressive and chemoresistant cancers.

The anti-tumor effect of OP-B on ovarian cancer in vitro and in vivo, and its mechanism: An investigation using network pharmacology-based analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Maidong (Liliaceae) is used as a yin-nourishing medication for the treatment of cardiovascular disease, inflammation, and assistant cancer chemotherapy in the clinic. Ophiopogonin B (OP-B), a major saponin extracted from Maidong, is reported to have potential antitumor activities against various human cancers. However, the effects of OP-B on human ovarian cancer (OC) and the potential mechanisms of action are yet elusive.

AIM OF THE STUDY

In this study, we aimed to explore the potential molecular mechanisms of OP-B in the treatment of OC using network pharmacology. In vivo and in vitro experiments were conducted to further verify the therapeutic effects of OP-B on OC.

MATERIALS AND METHODS

To investigate the functions of OP-B against OC holistically, the related targets of OP-B and OC were each predicted based on four public databases. Subsequently, the identified PPI network was constructed to detect the hub potential targets. In addition, GO and KEGG enrichment analysis were applied by Metascape database. Furthermore, we simultaneously investigated the anticancer effects of OP-B on SKOV3 and A2780 human ovarian cancer cells using a cell viability assay, transwell assay, and an image-based cytometric assay. The quantitative real-time PCR and western-blot assay were used to validate the RNA and protein levels of target genes in OP-B treated OC cells. At last, SKOV3-bearing BALB/c nude mice were applied to observe the effectiveness and toxicity of OP-B.

RESULTS

Through network pharmacological analysis, OP-B was found to play a critical role in OC via multiple targets and pathways, especially the STAT3 signaling pathways. In addition, in vitro experiments found OP-B suppressed SKOV3 and A2780 cells proliferation in a time and concentration dependent manner, and markedly impaired cancer cell migration. Flow cytometry analysis revealed that OP-B significantly increased early and late apoptosis, induced G2/M phase cell cycle arrest in SKOV3 cells and G0/G1 phase cell cycle arrest in A2780 cells. Moreover, OP-B administration down-regulated the expression of p-STAT3 protein, whereas the RNA expression and total protein levels of STAT3 were not altered. Finally, in vivo experiments confirmed the therapeutic effects of OP-B on OC in nude mice with low toxicity in heart, liver, lung, and kidney.

CONCLUSION

OP-B could efficiently suppress OC cellular proliferation, migration and induce apoptosis, cell cycle arrest mainly via the regulation of STAT3 signaling pathway. This study provides a promising potential application for an alternative to chemotherapy in ovarian cancer.

YTHDF2 promotes multiple myeloma cell proliferation via STAT5A/MAP2K2/p-ERK axis

Multiple myeloma (MM) is still incurable partially due to lacking effective therapeutic targets. Aberrant N6-methyladenosine (m6A) RNA modification plays a vital role in many cancers, however few researches are executed in MM. We first screened the m6A-related genes in MM patient cohorts and correlated these genes with patient outcomes. We found that YTHDF2, a well-recognized m6A reader, was increased in MM patients and associated with poor outcomes. Decreased YTHDF2 expression hampered MM cell proliferation in vitro and in vivo, while enforced YTHDF2 expression reversed those effects. The analyses of m6A-RIP-seq and RIP-PCR indicated that STAT5A was the downstream target of YTHDF2, which was binding to the m6A modification site of STAT5A to promote its mRNA degradation. ChIP-seq and PCR assays revealed that STAT5A suppressed MM cell proliferation by occupying the transcription site of MAP2K2 to decrease ERK phosphorylation. In addition, we confirmed that YTHDF2 mediated the unphosphorylated form of STAT5A to inhibit the expression of MAP2K2/p-ERK. In conclusion, our study highlights that YTHDF2/STAT5A/MAP2K2/p-ERK axis plays a key role in MM proliferation and targeting YTHDF2 may be a promising therapeutic strategy.

TRIM47 promotes ovarian cancer cell proliferation, migration, and invasion by activating STAT3 signaling

OBJECTIVES

Tripartite Motif 47 (TRIM47) protein plays a prominent role in many cancers. This study aimed to investigate the biological roles of TRIM47 in ovarian cancer.

METHODS

TRIM47 was knocked down and overexpressed in ovarian cancer cell lines SKOV3 and OVCAR3, and the effects on proliferation, clone formation, apoptosis, invasion, and growth of xenograft tumors in nude mice were determined. The expression levels of the selected candidates were tested by western blotting and quantitative real-time PCR.

RESULTS

TRIM47 knockdown suppressed proliferation and encourages apoptosis of ovarian cancer cells. Similarly, TRIM47 knockdown suppressed ovarian cancer cell invasion, migration, and epithelial-mesenchymal transition. Ovarian cancer cell xenograft assays demonstrated that TRIM47 knockdown significantly inhibited tumor growth. Mechanistically, TRIM47 knockdown suppressed STAT3 phosphorylation and the expression of several downstream genes, including MCL-1, MMP2, and c-MYC. Silencing of STAT3 partially prevented TRIM47-induced tumor cell proliferation and invasion.

CONCLUSION

The present study's findings demonstrate that by activating STAT3 signaling, TRIM47 functions as an oncogene in ovarian cancer. TRIM47, therefore, appears to be a potential target for ovarian cancer prevention and/or therapy.

PARP Inhibition Activates STAT3 in Both Tumor and Immune Cells Underlying Therapy Resistance and Immunosuppression In Ovarian Cancer

Despite the promising activity of poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) in many cancer types with defects in the DNA damage response the majority of the treated patients acquire PARPi resistance and succumb to their diseases. Consequently, there is an urgent need to identify the mechanisms of PARPi resistance. Here, we show that PARPi treatment promotes STAT3 activation in ovarian cancer cells, tumor-associated immune cells and fibroblasts, resulting in PARPi resistance and immunosuppression. Comparison of ovarian cancer patient-matched tumor biopsies before and after PARPi therapy revealed that STAT3 activity was significantly higher in tumor cells and tumor-associated immune cells and fibroblasts post PARPi treatment. Moreover, one-time PARPi treatment activated STAT3 both in tumor cells as well as diverse immune subsets and fibroblasts. PARPi-treated immune cells exhibited decreased expression of immunostimulatory interferon (IFN)-γ and Granzyme B while increasing immunosuppressive cytokine IL-10. Finally, we demonstrate that the acquisition of PARPi resistance in ovarian cancer cells was accompanied by increased STAT3 activity. Ablating STAT3 inhibited PARPi-resistant ovarian tumor cell growth and/or restored PARPi sensitivity. Therefore, our study has identified a critical mechanism intrinsic to PARPi that promotes resistance to PARPi and induces immunosuppression during PARPi treatment by activating STAT3 in tumor cells and tumor-associated immune cells/fibroblasts.

Gallic acid for cancer therapy: Molecular mechanisms and boosting efficacy by nanoscopical delivery

Cancer is the second leading cause of death worldwide. Majority of recent research efforts in the field aim to address why cancer resistance to therapy develops and how to overcome or prevent it. In line with this, novel anti-cancer compounds are desperately needed for chemoresistant cancer cells. Phytochemicals, in view of their pharmacological activities and capacity to target various molecular pathways, are of great interest in the development of therapeutics against cancer. Plant-derived-natural products have poor bioavailability which restricts their anti-tumor activity. Gallic acid (GA) is a phenolic acid exclusively found in natural sources such as gallnut, sumac, tea leaves, and oak bark. In this review, we report on the most recent research related to anti-tumor activities of GA in various cancers with a focus on its underlying molecular mechanisms and cellular pathwaysthat that lead to apoptosis and migration of cancer cells. GA down-regulates the expression of molecular pathways involved in cancer progression such as PI3K/Akt. The co-administration of GA with chemotherapeutic agents shows improvements in suppressing cancer malignancy. Various nano-vehicles such as organic- and inorganic nano-materials have been developed for targeted delivery of GA at the tumor site. Here, we suggest that nano-vehicles improve GA bioavailability and its ability for tumor suppression.

Circ-E2F3 promotes cervical cancer progression by inhibiting microRNA-296-5p and increasing STAT3 nuclear translocation

Circular RNA E2F transcription factor 3 (circ-E2F3) has been demonstrated to be differentially expressed in some diseases and cancers. However, the role of circ-E2F3 in cervical cancer (CC) progression remains unclear. Therefore, we aimed to elucidate the mechanism of circ-E2F3 regulation of CC progression. Circ-E2F3 expression was determined in CC samples, and its correlation with the clinicopathological characteristics of CC patients and cell biological processes was examined. The interaction among circ-E2F3, microRNA-296-5p (miR-296-5p), and signal transducer and activator of transcription 3 (STAT3) was analyzed by dual luciferase reporter gene and fluorescence in situ hybridization assays. Circ-E2F3-depleted CaSki cells were implanted into nude mice to verify the function of circ-E2F3 in vivo. Circ-E2F3 was upregulated in both CC tissues and cell lines, and this correlated with the clinicopathological features and poor prognosis of CC patients. Moreover, circ-E2F3 promoted the proliferation, invasion, and migration of CC cells and tumor growth in vivo. It was also observed that circ-E2F3 promoted the nuclear translocation of STAT3 through inhibition of miR-296-5p, thus affecting the expression of cyclin D1. Taken together, the key findings of our study demonstrate that circ-E2F3 induces inhibition of miR-296-5p, which triggers activation and nuclear translocation of STAT3 that then upregulates cyclin D1 expression.

A Novel Monoclonal Antibody Targeting Cancer-Specific Plectin Has Potent Antitumor Activity in Ovarian Cancer

Cancer-specific plectin (CSP) is a pro-tumorigenic protein selectively expressed on the cell surface of major cancers, including ovarian cancer (OC). Despite its assessable localization, abundance, and functional significance, the therapeutic efficacy of targeting CSP remains unexplored. Here, we generated and investigated the anticancer effects of a novel CSP-targeting monoclonal antibody, 1H11, in OC models. Its therapeutic efficacy as a monotherapy and in combination with chemotherapy was evaluated in vitro using two OC cell lines and in vivo by a subcutaneous ovarian cancer model. 1H11 demonstrated rapid internalization and high affinity and specificity for both human and murine CSP. Moreover, 1H11 induced significant and selective cytotoxicity (EC₅₀ = 260 nM), G0/G1 arrest, and decreased OC cell migration. Mechanistically, these results are associated with increased ROS levels and reduced activation of the JAK2-STAT3 pathway. In vivo, 1H11 decreased Ki67 expression, induced 65% tumor growth inhibition, and resulted in 30% tumor necrosis. Moreover, 1H11 increased chemosensitivity to cisplatin resulting in 60% greater tumor growth inhibition compared to cisplatin alone. Taken together, CSP-targeting with 1H11 exhibits potent anticancer activity against ovarian cancer and is deserving of future clinical development.

Connections between prolactin and ovarian cancer

Ovarian cancer (OC) is characterized by a high morbidity and mortality, highlighting a great need for a better understanding of biological mechanisms that affect OC progression and improving its early detection methods. This study investigates effects of prolactin (PRL) on ovarian cancer cells, analyzes PRL receptors (PRLR) in tissue micro arrays and relates PRLR expression to survival of ovarian cancer. A database, composed of transcript profiles from OC, was searched for PRLR expression and results were put in relation to survival. Expression of PRLR in OC tissue sections and OC cell lines SKOV3, OV2008 and OVSAHO was assessed using immunohistochemistry, western blots and quantitative real-time PCR. The biological function of PRLR was evaluated by proliferation, colony formation and wound healing assays. Levels of PRLR mRNA are related to survival; in epithelial OC a high PRLR mRNA expression is related to a shorter survival. Analysis of a tissue micro array consisting of 84 OC showed that 72% were positive for PRLR immuno-staining. PRLR staining tended to be higher in OC of high grade tumors compared to lower grades. PRLR mRNA and protein can further be detected in OC cell lines. Moreover, in vitro treatment with PRL significantly activated the JAK/STAT pathway. PRLR expression is associated with OC survivals. PRL and its receptor may play an onco-modulatory role and promote tumor aggressiveness in OC. Alternatively, increased PRLR levels may form a base for the development of PRLR antagonist or PRLR antagonist-drug conjugate to increase selective uptake of anti-cancer drugs.

IFN-γ inhibits ovarian cancer progression via SOCS1/JAK/STAT signaling pathway

PURPOSE

Ovarian cancer (OC) is a common malignancy, and IFN-γ, a multifunctional cytokine, is unveiled to impede the multiplication and enhance apoptosis in diverse tumor cells in previous research. Nonetheless, its function and mechanism in OC are blurred.

METHODS

OC cell lines SKOV3 and OVCAR3 were dealt with different concentrations (0-40 ng/ml) of IFN-γ. CCK-8 experiment was utilized to examine cell multiplication; Flow cytometry was executed to detect apoptosis and cell cycle; Wound healing assay was utilized to detect cell migration; and Transwell experiment was implemented to examine cell invasion. qRT-PCR analysis was applied to detect STAT5, STAT3, JAK2 and JAK3 mRNA expression in OC cell lines. Western blot experiment was applied to detect the protein and phosphorylation levels of SOCS1, STAT5 and STAT3.

RESULTS

IFN-γ suppressed OC cell multiplication in a concentration-dependent manner. Relative to the control group, IFN-γ restrained OC cell migration, invasion, enhanced apoptosis and prevented cell transformation from G0/G1 to S phase. Further analysis revealed that IFN-γ up-modulated SOCS1 expression and impeded STAT5 and STAT3 protein phosphorylation levels, and knockdown of SOCS1 partially counteracted the inhibitory effect of IFN-γ on STAT5 and STAT3 protein phosphorylation levels.

CONCLUSION

IFN-γ represses OC progression by facilitating SOCS1 to suppress STAT3 and STAT5 protein phosphorylation.

The Molecular Landscape Influencing Prognoses of Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) is one of the major increasing lethal malignancies of the gynecological tract, mostly due to delayed diagnosis and chemoresistance, as well as its very heterogeneous genetic makeup. Application of high-throughput molecular technologies, gene expression microarrays, and powerful preclinical models has provided a deeper understanding of the molecular characteristics of EOC. Therefore, molecular markers have become a potent tool in EOC management, including prediction of aggressiveness, prognosis, and recurrence, and identification of novel therapeutic targets. In addition, biomarkers derived from genomic/epigenomic alterations (e.g., gene mutations, copy number aberrations, and DNA methylation) enable targeted treatment of affected signaling pathways in advanced EOC, thereby improving the effectiveness of traditional treatments. This review outlines the molecular landscape and discusses the impacts of biomarkers on the detection, diagnosis, surveillance, and therapeutic targets of EOC. These findings focus on the necessity to translate these potential biomarkers into clinical practice.

MTHFD2 promotes ovarian cancer growth and metastasis via activation of the STAT3 signaling pathway

Methylenetetrahydrofolate dehydrogenase 2 (MTHFD2) is a bifunctional enzyme located in the mitochondria. MTHFD2 has been reported to be overexpressed in several malignant tumors and is implicated in cancer development. This study aimed to investigate the effect of MTHFD2 on ovarian cancer progression. The expression of MTHFD2 was detected by bioinformatic analysis, immunohistochemistry, RT‐qPCR (real‐time quantitative PCR analysis), and western blot analysis. The effects of MTHFD2 depletion on cell proliferation, migration, and invasion were determined through in vitro experiments. Cell cycle progression and apoptosis were accessed by flow cytometry. The related signaling pathway protein expression was determined by western blot analysis. We found that MTHFD2 is highly expressed in both ovarian cancer tissues and cell lines. MTHFD2 deletion suppressed cell proliferation and metastasis. Knockdown of MTHFD2 induces cell apoptosis and G2/M arrest, whereas the number of cells in S phase increased with MTHFD2 overexpression. Mechanically, our results indicate that an inhibitory effect of MTHFD2 knockdown may be mediated by the downregulation of cyclin B1/Cdc2 complex and the inhibitory effect on its activity. Additionally, MTHFD2 could regulate cell growth and aggressiveness via activation of STAT3 and the STAT3‐induced epithelial–mesenchymal transition signaling pathway. These findings indicate that MTHFD2 is overexpressed in ovarian cancer and regulates cell proliferation and metastasis, presenting an attractive therapeutic target.

Long non-coding RNA HAL suppresses the migration and invasion of serous ovarian cancer by inhibiting EMT signaling pathway

OBJECTIVE

To investigate the specific function of long non-coding RNA HAL in serous ovarian cancer (SOC) and to further clarify the regulation of HAL on EMT pathway.

MATERIALS AND METHODS

The expression of HAL and TWIST1 was detected by qRT-PCR. CCK8 assay, wound healing assay, transwell assay and flow cytometry were used to detect the HAL function on proliferation, migration, invasion and apoptosis in SOC cells. Western blot was used to calculate protein level of Vimentin, N-cadherin and E-cadherin. The effect of HAL on tumorigenesis of SOC was confirmed by xenograft nude mice model.

RESULTS

HAL was significantly decreased in SOC tissues and cells. Overexpression of HAL inhibited the proliferation, migration and invasion of SKOV3 cells, but promoted apoptosis. Furthermore, overexpression of HAL decreased the mRNA and protein levels of TWIST1 via a binding between HAL and TWIST1. Forced expression of TWIST1 reversed the inhibitory role of HAL on SOC cells' migration and invasion. The in vivo tumor growth assay showed that HAL suppressed SOC tumorigenesis with inhibiting EMT pathway.

CONCLUSIONS

Our research emphasized HAL acting as a tumor-inhibiting gene by regulating EMT signaling pathway, thus providing some novel experimental basis for clinical treatment of SOC.

Syringic acid regulates suppression of the STAT3/JNK/AKT pathway via inhibition of human ovarian teratoma cancer cell (PA-1) growth-in vitro study

Among the various gynaecological cancers, ovarian cancer (OC) is the third most severe cancer worldwide affecting women. Syringic acid (SRA) exhibits several hypoglycaemia, antioxidant, and anti-inflammatory properties. The study aimed to examine the proapoptotic activities of SRA on OC in PA-1 cells. SRA has been shown to decrease cell viability, increase the rate of cell apoptosis, and cause mitochondrial membrane potential to dissipate and induce over-accumulation of intracellular reactive oxygen species in PA-1 cells after 24 h of exposure. We examined the anticancer efficacy of SRA with its responsible molecular mechanism in the PA-1 cell lines of human OC. In a dose-dependent manner, SRA substantially suppressed cell proliferation and migration. SRA exhibited significant downregulation of cyclins including CDK2, CDK4, and Cyclin D1 responsible for cell-cycle regulation. The apoptosis-mediated anticancer activity was mainly mediated through caspase-3, caspase-8, caspase-9 and Bax upregulation, and Bcl-2 downregulation. We report that SRA significantly inhibits the expression of signal transducer and activator of transcription 3 (STAT3), c-Jun N-terminal kinase (JNK), P65, and protein kinase B (AKT) pathways. These findings depict the effective inhibition of STAT3, p38, and AKT expression by SRA, making it a potential therapeutic candidate for human OC.

Transcriptional dysregulation of TRIM29 promotes colorectal cancer carcinogenesis via pyruvate kinase-mediated glucose metabolism

Targeted molecular therapy is the most effective treatment for cancer. An effective therapeutic target for colorectal cancer (CRC) is urgently needed. However, the mechanisms of CRC remain poorly understood, which has hampered research and development of CRC-targeted therapy. TRIM29 is a ubiquitin E3 ligase that has been reported as an oncogene in several human tumors. In this study, we show that increased levels of TRIM29 were detected in CRC compared with normal tissues and were associated with poor clinical outcome, advanced stage and lymph node metastasis, particularly those with right-sided colorectal cancer (RSCC). Notably, GATA2 (GATA Binding Protein 2) transcriptionally repressed TRIM29 expression. The loss of GATA2 and high expression of TRIM29 occur more frequently in RSCC than in left-sided colorectal cancer (LSCC). Functional assays revealed that TRIM29 promotes the malignant CRC phenotype in vitro and in vivo. Mechanistic analyses indicate that TRIM29 promotes pyruvate kinase (mainly PKM1) degradation via the ubiquitin-proteasome pathway. TRIM29 directly targets PKM1 to reduce PKM1/PKM2 ratio, which results in PKM2-mediated aerobic glycolysis (Warburg effect) acting as the dominant energy source in CRC. Our findings suggest that TRIM29 acts as a tumor promoter in CRC, especially in RSCC, and is a potential therapeutic target for CRC treatment.

Curcumin Nanoparticle Enhances the Anticancer Effect of Cisplatin by Inhibiting PI3K/AKT and JAK/STAT3 Pathway in Rat Ovarian Carcinoma Induced by DMBA

Cisplatin has been used for decades for the treatment of ovarian cancer. However, despite its potent anticancer effect, cisplatin's efficacy as a single agent was inadequate in patients with advanced stage. Curcumin has been shown to sensitize cisplatin activity in several cancer models. However, the low bioavailability of curcumin has limited its anticancer potential. Hence, nano-formulation of curcumin was developed to increase its therapeutic efficacy in ovarian cancer. The objective of this study was to investigate the mechanism of curcumin nanoparticles given in combination with cisplatin in rat ovarian carcinoma induced by dimethylbenz(a)anthracene (DMBA). The administration of cisplatin and nanocurcumin resulted in a significant reduction in ovarian tumor volume and weight. Furthermore, there were reduction in expressions of Ki67, TGF-β, PI3K, and Akt phosphorylation. Co-treatment of cisplatin and nanocurcumin also reduced JAK expression, STAT3 phosphorylation, and reduced IL-6 concentrations. Altogether, nanocurcumin, given as a co-treatment with cisplatin has therapeutic potential in ovarian cancer models by inhibiting proliferation through downregulation of PI3K/Akt and JAK/STAT3 signaling pathways.

Dual relationship between long non-coding RNAs and STAT3 signaling in different cancers: New insight to proliferation and metastasis

Uncontrolled growth and metastasis of cancer cells is an increasing challenge for overcoming cancer, and improving survival of patients. Complicated signaling networks account for proliferation and invasion of cancer cells that need to be elucidated for providing effective cancer therapy, and minimizing their malignancy. Long non-coding RNAs (lncRNAs) are RNA molecules with a length of more than 200 nucleotides. They participate in cellular events, and their dysregulation in a common phenomenon in different cancers. Noteworthy, lncRNAs can regulate different molecular pathways, and signal transducer and activator of transcription 3 (STAT3) is one of them. STAT3 is a tumor-promoting factors in cancers due to its role in cancer proliferation (cell cycle progression and apoptosis inhibition) and metastasis (EMT induction). LncRNAs can function as upstream mediators of STAT3 pathway, reducing/enhancing its expression. This dual relationship is of importance in affecting proliferation and metastasis of cancer cells. The response of cancer cells to therapy such as chemotherapy and radiotherapy is regulated by lncRNA/STAT3 axis. Tumor-promoting lncRNAs including NEAT1, SNHG3 and H19 induces STAT3 expression, while tumor-suppressing lncRNAs such as MEG3, PTCSC3 and NKILA down-regulate STAT3 expression. Noteworthy, upstream mediators of STAT3 such as microRNAs can be regulated by lncRNAs. These complicated signaling networks are mechanistically described in the current review.

The underlying molecular mechanism and identification of transcription factor markers for laryngeal squamous cell carcinoma

The screening and treatment of laryngeal squamous cell carcinoma (LSCC) still perplexes clinicians, making it necessary to explore new markers. To this end, this research examined the underlying molecular mechanism of LSCC based on high-throughput datasets (n = 249) from multiple databases. It also identified transcription factors (TFs) independently associated with LSCC prognosis. Through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses, differential expression genes of LSCC were deemed relevant to the extracellular matrix and its related structures or pathways, suggesting that the extracellular matrix plays an important role in LSCC. At the same time, several hub genes that may also have important roles in LSCC were identified via protein–protein interaction analysis, including CDC45, TPX2, AURKA, KIF2C, NUF, MUC1, MUC7, MUC4, MUC15, and MUC21. Eight unreported LSCC prognostic TFs – BCAT1, CHD4, FOXA2, GATA6, HNF1A, HOXB13, MAFF, and TCF4 – were screened via Kaplan–Meier curves. Cox analysis determined for the first time that HOXB13 expression and gender were independently associated with LSCC prognosis. Compared to control tissues, elevated expression of HOXB13 was found in LSCC tissues (standardized mean difference = 0.44, 95% confidence interval [0.13–0.76]). HOXB13 expression also makes it feasible to screen LSCC from non-LSCC (area under the curve = 0.77), and HOXB13 may play an essential role in LSCC by regulating HOXB7. In conclusion, HOXB13 may be a novel marker for LSCC clinical screening and treatment.

Krupple-Like Factor 5 is a Potential Therapeutic Target and Prognostic Marker in Epithelial Ovarian Cancer

Epithelial ovarian cancer (EOC) is the most lethal gynecological malignancy. Despite current therapeutic and surgical options, advanced EOC shows poor prognosis. Identifying novel molecular therapeutic targets is highly needed in the management of EOC. Krupple-like factor 5 (KLF5), a zinc-finger transcriptional factor, is highly expressed in a variety of cancer types. However, its role and expression in EOC is not fully illustrated. Immunohistochemical analysis was performed to assess KLF5 protein expression in 425 primary EOC samples using tissue microarray. We also addressed the function of KLF5 in EOC and its interaction with signal transducer and activator of transcription 3 (STAT3) signaling pathway. We found that KLF5 overexpressed in 53% (229/425) of EOC samples, and is associated with aggressive markers. Forced expression of KLF5 enhanced cell growth in low expressing EOC cell line, MDAH2774. Conversely, knockdown of KLF5 reduced cell growth, migration, invasion and progression of epithelial to mesenchymal transition in KLF5 expressing cell lines, OVISE and OVSAHO. Importantly, silencing of KLF5 decreased the self-renewal ability of spheroids generated from OVISE and OVSAHO cell lines. In addition, downregulation of KLF5 potentiated the effect of cisplatin to induce apoptosis in these cell lines. These data reveals the pro-tumorigenic role of KLF5 in EOC and uncover its role in activation of STAT3 signaling pathway, suggesting the importance of KLF5 as a potential therapeutic target for EOC therapy.

CD44 in Ovarian Cancer Progression and Therapy Resistance-A Critical Role for STAT3

Despite significant progress in cancer therapy over the last decades, ovarian cancer remains the most lethal gynecologic malignancy worldwide with the five-year overall survival rate less than 30% due to frequent disease recurrence and chemoresistance. CD44 is a non-kinase transmembrane receptor that has been linked to cancer metastatic progression, cancer stem cell maintenance, and chemoresistance development via multiple mechanisms across many cancers, including ovarian, and represents a promising therapeutic target for ovarian cancer treatment. Moreover, CD44-mediated signaling interacts with other well-known pro-tumorigenic pathways and oncogenes during cancer development, such as signal transducer and activator of transcription 3 (STAT3). Given that both CD44 and STAT3 are strongly implicated in the metastatic progression and chemoresistance of ovarian tumors, this review summarizes currently available evidence about functional crosstalk between CD44 and STAT3 in human malignancies with an emphasis on ovarian cancer. In addition to the role of tumor cell-intrinsic CD44 and STAT3 interaction in driving cancer progression and metastasis, we discuss how CD44 and STAT3 support the pro-tumorigenic tumor microenvironment and promote tumor angiogenesis, immunosuppression, and cancer metabolic reprogramming in favor of cancer progression. Finally, we review the current state of therapeutic CD44 targeting and propose superior treatment possibilities for ovarian cancer.

LncRNAs in Ovarian Cancer Progression, Metastasis, and Main Pathways: ceRNA and Alternative Mechanisms

Ovarian cancer (OvCa) develops asymptomatically until it reaches the advanced stages with metastasis, chemoresistance, and poor prognosis. Our review focuses on the analysis of regulatory long non-coding RNAs (lncRNAs) competing with protein-coding mRNAs for binding to miRNAs according to the model of competitive endogenous RNA (ceRNA) in OvCa. Analysis of publications showed that most lncRNAs acting as ceRNAs participate in OvCa progression: migration, invasion, epithelial-mesenchymal transition (EMT), and metastasis. More than 30 lncRNAs turned out to be predictors of survival and/or response to therapy in patients with OvCa. For a number of oncogenic (CCAT1, HOTAIR, NEAT1, and TUG1 among others) and some suppressive lncRNAs, several lncRNA/miRNA/mRNA axes were identified, which revealed various functions for each of them. Our review also considers examples of alternative mechanisms of actions for lncRNAs besides being ceRNAs, including binding directly to mRNA or protein, and some of them (DANCR, GAS5, MALAT1, and UCA1 among others) act by both mechanisms depending on the target protein. A systematic analysis based on the data from literature and Panther or KEGG (Kyoto Encyclopedia of Genes and Genomes) databases showed that a significant part of lncRNAs affects the key pathways involved in OvCa metastasis, EMT, and chemoresistance.

Functional Analysis of O-GlcNAcylation in Cancer Metastasis

One common and reversible type of post-translational modification (PTM) is the addition of O-linked β-N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation), and its dynamic balance is controlled by O-GlcNAc transferase (OGT) and glycoside hydrolase O-GlcNAcase (OGA) through the addition or removal of O-GlcNAc groups. A large amount of research data confirms that proteins regulated by O-GlcNAcylation play a pivotal role in cells. In particularly, imbalanced levels of OGT and O-GlcNAcylation have been found in various types of cancers. Recently, increasing evidence shows that imbalanced O-GlcNAcylation directly or indirectly impacts the process of cancer metastasis. This review summarizes the current understanding of the influence of O-GlcNAc-proteins on the regulation of cancer metastasis. It will provide a theoretical basis to further elucidate of the molecular mechanisms underlying cancer emergence and progression.

Targeting STAT3 and STAT5 in Cancer

Insights into the mutational landscape of the human cancer genome coding regions defined about 140 distinct cancer driver genes in 2013, which approximately doubled to 300 in 2018 following advances in systems cancer biology studies [...].

CCDC7 Activates Interleukin-6 and Vascular Endothelial Growth Factor to Promote Proliferation via the JAK-STAT3 Pathway in Cervical Cancer Cells

Objective

Tumor growth is one of the most lethal attributes of human malignancy. The expression of CCDC7, a novel gene which has multiple functions, has been shown to be associated with tumor growth and poor prognosis in patients with cancer. However, the specific functions of CCDC7 remain unclear. Here, we investigated the molecular mechanisms underlying the effects of CCDC7 on proliferation in cervical cancer.

Materials and Methods

The MTT and EdU assays were performed to evaluate the function of CCDC7. The immunohistochemical, quantitative real-time PCR (qRT-PCR), ELISA and Western blot assay were used to detect the gene and protein expression in tissues and cells. A xenograft test was conducted to detect the impact of CCDC7 on tumor development in vivo .

Results

In immunohistochemical analysis of 193 cases, normal cervical tissue and cervical cancer tissue show that CCDC7 expression is closely correlated with the development of cervical cancer and was positively correlated with the clinical stage and histological grade. Overexpression or knockdown of CCDC7 affected cell proliferation in cervical cancer cells in vitro. In a nude mouse xenograft model in vivo, knockdown of CCDC7 inhibited cell proliferation and tumor growth. Furthermore, CCDC7 overexpression upregulated interleukin (IL)-6 and vascular endothelial growth factor (VEGF) at mRNA and protein levels, and treatment with recombinant IL-6 or VEGF proteins also increased CCDC7 expression. In a case set of 80 patients with cervical cancer, we found that CCDC7, IL-6, and VEGF affected patient prognosis. Finally, inhibition of various signaling pathways using specific inhibitors indicated that CCDC7 blocked the decrease in cell proliferation observed following suppression of the JAK-STAT3 pathway, suggesting that CCDC7 functioned via this critical signaling network.

Conclusion

Those findings indicated that CCDC7 may be a novel target for the treatment of cervical cancer and may have applications as a predictive marker for tumor growth in cervical carcinoma.

STAT3 Pathway in Gastric Cancer: Signaling, Therapeutic Targeting and Future Prospects

Molecular signaling pathways play a significant role in the regulation of biological mechanisms, and their abnormal expression can provide the conditions for cancer development. The signal transducer and activator of transcription 3 (STAT3) is a key member of the STAT proteins and its oncogene role in cancer has been shown. STAT3 is able to promote the proliferation and invasion of cancer cells and induces chemoresistance. Different downstream targets of STAT3 have been identified in cancer and it has also been shown that microRNA (miR), long non-coding RNA (lncRNA) and other molecular pathways are able to function as upstream mediators of STAT3 in cancer. In the present review, we focus on the role and regulation of STAT3 in gastric cancer (GC). miRs and lncRNAs are considered as potential upstream mediators of STAT3 and they are able to affect STAT3 expression in exerting their oncogene or onco-suppressor role in GC cells. Anti-tumor compounds suppress the STAT3 signaling pathway to restrict the proliferation and malignant behavior of GC cells. Other molecular pathways, such as sirtuin, stathmin and so on, can act as upstream mediators of STAT3 in GC. Notably, the components of the tumor microenvironment that are capable of targeting STAT3 in GC, such as fibroblasts and macrophages, are discussed in this review. Finally, we demonstrate that STAT3 can target oncogene factors to enhance the proliferation and metastasis of GC cells.

Novel Nanocomplexes Targeting STAT3 Demonstrate Promising Anti-Ovarian Cancer Effects in vivo

Background

Cationic solid lipid nanoparticles (SLN) have attracted intensive interest as an effective gene delivery system for its high biocompatibility, stability and low cytotoxicity. In our previous study, we successfully prepared SLN-STAT3 decoy ODN complexes and made a primary study on its antitumor behavior in ovarian cancer cells in vitro. However, there is little information available so far about the effect of SLN-STAT3 decoy ODN complexes on ovarian cancer in vivo, either little information about the pharmacological toxicology in vivo.

Material and Methods

We applied nanotechnology to improve the gene delivery system and synthesize SLN-STAT3 decoy ODN complexes. Xenograft mouse models were established to assess the antitumor effects of SLN-STAT3 decoy ODN on the tumor growth of ovarian cancer in vivo. To analyze the mechanisms of SLN-STAT3 decoy ODN, we investigated apoptosis, autophagy, epithelial–mesenchymal transition (EMT) in tumor tissues of nude mice and investigated the effects and toxicology of SLN-STAT3 decoy ODN complexes on the vital organs of nude mice.

Results

The results showed that SLN-STAT3 decoy ODN complexes markedly inhibited tumor growth in vivo. SLN-STAT3 decoy ODN complexes could induce cell apoptosis through downregulating Bcl-2, survivin and pro caspase 3, but upregulating Bax and cleaved caspase 3. These complexes could also regulate autophagy through upregulating LC3A-II, LC3B-II and beclin-1, but downregulating p-Akt and p-mTOR. Moreover, these complexes could inhibit cancer cell invasion through reversing EMT. Besides, SLN-STAT3 decoy ODN complexes showed no obvious toxicity on vital organs and hematological parameters of nude mice.

Conclusion

The molecular mechanisms that SLN-STAT3 decoy ODN complexes inhibit tumor growth involved activating the apoptotic cascade, regulating autophagy, and reversing EMT program; and these complexes showed no obvious toxicity on nude mice. Our study indicated that the nanocomplexes SLN-STAT3 decoy ODN might be a promising therapeutic approach for ovarian cancer treatment.

Expression of CD44v6-Containing Isoforms Influences Cisplatin Response in Gastric Cancer Cells

CD44v6-containing isoforms are frequently de novo expressed in gastric cancer (GC). Whether CD44v6 has a central role in GC transformation and/or progression, whether it conditions response to therapy or whether it is only a bystander marker is still not known. Therefore, we aimed to clarify the role of CD44v6 in GC. We generated GC isogenic cell lines stably expressing CD44s or CD44v6 and tested them for different cancer hallmarks and response to cisplatin, and we further confirmed our findings in cells that endogenously express CD44v6. No correlation between overexpression of CD44v6 and the tested cancer hallmarks was observed, suggesting CD44v6 is not a driver of GC progression. Upon cisplatin treatment, CD44v6+ cells survive better and have lower apoptosis levels than CD44v6− cells, possibly due to concomitant activation of STAT3 and P38. In co-culture experiments, we discovered that CD44v6+ cells are involved in GC cell overgrowth after cisplatin treatment. In conclusion, we show that CD44v6 expression increases cell survival in response to cisplatin treatment in GC cells and that these cells override CD44v6-negative cells after cisplatin-treatment. This suggests that tumor expression of CD44v6-containing variants may condition the outcome of GC patients treated with chemotherapy.