The role of JNK in prostate cancer progression and therapeutic strategies

Silver nanoparticle-induced cell damage via impaired mtROS-JNK/MnSOD signaling pathway

This study investigated the mechanism of silver nanoparticle (AgNP) cytotoxicity from a mitochondrial perspective. The effect of AgNP on manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant enzyme, against oxidative stress has not been studied in detail. We demonstrated that AgNP decreased MnSOD mRNA level, protein expression, and activity in human Chang liver cells in a time-dependent manner. AgNP induced the production of mitochondrial reactive oxygen species (mtROS), particularly superoxide anion. AgNP was found to increase mitochondrial calcium level and disrupt mitochondrial function, leading to reduced ATP level, succinate dehydrogenase activity, and mitochondrial permeability. AgNP induced cytochrome c release from the mitochondria into the cytoplasm, attenuated the expression of the anti-apoptotic proteins phospho Bcl-2 and Mcl-1, and induced the expression of the pro-apoptotic proteins Bim and Bax. In addition, c-Jun N-terminal kinase (JNK) phosphorylation was significantly increased by AgNP. Treatment with elamipretide (a mitochondria-targeted antioxidant) and SP600125 (a JNK inhibitor) showed the involvement of MnSOD and JNK in these processes. These results indicated that AgNP damaged human Chang liver cells by destroying mitochondrial function through the accumulation of mtROS.

Anti-metastatic effects of AGS-30 on breast cancer through the inhibition of M2-like macrophage polarization

AGS-30, a new andrographolide derivative, showed significant anticancer and anti-angiogenic characteristics. However, its role in controlling macrophage polarization and tumor immune response is unknown. Thus, the main goals of this study are to investigate how AGS-30 regulates macrophage polarization and how it suppresses breast cancer metastasis. AGS-30 inhibited IL-4 and IL-13-induced RAW 264.7 and THP-1 macrophages into M2-like phenotype. However, AGS-30 did not affect the LPS and IFN-γ-induced polarization of M1-like macrophages. AGS-30 reduced the mRNA expressions of CD206, Arg-1, Fizz-1, Ym-1, VEGF, IL-10, MMP2, and MMP9 in M2-like macrophages in a concentration-dependent manner. In contrast, andrographolide treatment at 5 μM did not affect M1-like and M2-like macrophage polarization. The conditioned medium from M2-like macrophages increased 4T1 breast cancer cell migration and invasion, whereas AGS-30 inhibited these effects. In the 4T1 breast tumor xenograft mice, the tumor volume and weight were reduced without affecting body weight after receiving AGS-30. AGS-30 treatment also reduced lung and liver metastasis, with reduced STAT6, CD31, VEGF, and Ki67 protein expressions. Moreover, the tumors had considerably fewer M2-like macrophages and Arg-1 expression, but the proportion of M1-like macrophages and iNOS expression increased after AGS-30 treatment. Same results were found in the tail vein metastasis model. In conclusion, this study shows that AGS-30 inhibits breast cancer growth and metastasis, probably through inhibiting M2-like macrophage polarization. Our findings suggest that AGS-30 may be a potential immunotherapeutic alternative for metastatic breast cancer.

The Role of the Dysregulated JNK Signaling Pathway in the Pathogenesis of Human Diseases and Its Potential Therapeutic Strategies: A Comprehensive Review

JNK is named after c-Jun N-terminal kinase, as it is responsible for phosphorylating c-Jun. As a member of the mitogen-activated protein kinase (MAPK) family, JNK is also known as stress-activated kinase (SAPK) because it can be activated by extracellular stresses including growth factor, UV irradiation, and virus infection. Functionally, JNK regulates various cell behaviors such as cell differentiation, proliferation, survival, and metabolic reprogramming. Dysregulated JNK signaling contributes to several types of human diseases. Although the role of the JNK pathway in a single disease has been summarized in several previous publications, a comprehensive review of its role in multiple kinds of human diseases is missing. In this review, we begin by introducing the landmark discoveries, structures, tissue expression, and activation mechanisms of the JNK pathway. Next, we come to the focus of this work: a comprehensive summary of the role of the deregulated JNK pathway in multiple kinds of diseases. Beyond that, we also discuss the current strategies for targeting the JNK pathway for therapeutic intervention and summarize the application of JNK inhibitors as well as several challenges now faced. We expect that this review can provide a more comprehensive insight into the critical role of the JNK pathway in the pathogenesis of human diseases and hope that it also provides important clues for ameliorating disease conditions.

Evaluation of novel pyrazol-4-yl pyridine derivatives possessing arylsulfonamide tethers as c-Jun N-terminal kinase (JNK) inhibitors in leukemia cells

A series of 36 pyrazol-4-yl pyridine derivatives (8a-i, 9a-i, 10a-i, and 11a-i) was designed, synthesized, and evaluated for its antiproliferative activity over NCI-60 cancer cell line panel and inhibitory effect against JNK isoforms (JNK1, JNK2, and JNK3). All the synthesized compounds were tested against the NCI-60 cancer cell line panel. Compounds 11b, 11c, 11g, and 11i were selected to determine their GI50s and exerted a superior potency over the reference standard SP600125 against the tested cell lines. 11c showed a GI50 of 1.28 μM against K562 leukemic cells. Vero cells were used to assess 11c cytotoxicity compared to the tested cancer cells. The target compounds were tested against hJNK isoforms in which compound 11e exhibited the highest potency against JNK isoforms with IC50 values of 1.81, 12.7, and 10.5 nM against JNK1, JNK2, and JNK3, respectively. Kinase profiling of 11e showed higher JNK selectivity in 50 kinase panels. Compounds 11c and 11e showed cell population arrest at the G2/M phase, induced early apoptosis, and slightly inhibited beclin-1 production at higher concentrations in K562 leukemia cells relative to SP600125. NanoBRET assay of 11e showed intracellular JNK1 inhibition with an IC50 of 2.81 μM. Also, it inhibited CYP2D6 and 3A4 with different extent and its hERG activity showed little cardiac toxicity with an IC50 of 4.82 μM. hJNK3 was used as a template to generate the hJNK1 crystal structure to explore the binding mode of 11e (PDB ID: 8ENJ) with a resolution of 2.8 °A and showed a typical type I kinase inhibition against hJNK1. Binding energy scores showed that selectivity of 11e towards JNK1 could be attributed to additional hydrophobic interactions relative to JNK3.

Effects of Dickkopf-1 (DKK-1) on Prostate Cancer Growth and Bone Metastasis

Osteoblastic bone metastases are commonly detected in patients with advanced prostate cancer (PCa) and are associated with an increased mortality rate. Dickkopf-1 (DKK-1) antagonizes canonical WNT/β-catenin signaling and plays a complex role in bone metastases. We explored the function of cancer cell-specific DKK-1 in PCa growth, metastasis, and cancer-bone interactions using the osteoblastic canine PCa cell line, Probasco. Probasco or Probasco + DKK-1 (cells transduced with human DKK-1) were injected into the tibia or left cardiac ventricle of athymic nude mice. Bone metastases were detected by bioluminescent imaging in vivo and evaluated by micro-computed tomography and histopathology. Cancer cell proliferation, migration, gene/protein expression, and their impact on primary murine osteoblasts and osteoclasts, were evaluated in vitro. DKK-1 increased cancer growth and stimulated cell migration independent of canonical WNT signaling. Enhanced cancer progression by DKK-1 was associated with increased cell proliferation, up-regulation of NF-kB/p65 signaling, inhibition of caspase-dependent apoptosis by down-regulation of non-canonical WNT/JNK signaling, and increased expression of epithelial-to-mesenchymal transition genes. In addition, DKK-1 attenuated the osteoblastic activity of Probasco cells, and bone metastases had decreased cancer-induced intramedullary woven bone formation. Decreased bone formation might be due to the inhibition of osteoblast differentiation and stimulation of osteoclast activity through a decrease in the OPG/RANKL ratio in the bone microenvironment. The present study indicated that the cancer-promoting role of DKK-1 in PCa bone metastases was associated with increased growth of bone metastases, reduced bone induction, and altered signaling through the canonical WNT-independent pathway. DKK-1 could be a promising therapeutic target for PCa.

A conserved mechanism for JNK-mediated loss of Notch function in advanced prostate cancer

Dysregulated Notch signaling is a common feature of cancer; however, its effects on tumor initiation and progression are highly variable, with Notch having either oncogenic or tumor-suppressive functions in various cancers. To better understand the mechanisms that regulate Notch function in cancer, we studied Notch signaling in a Drosophila tumor model, prostate cancer-derived cell lines, and tissue samples from patients with advanced prostate cancer. We demonstrated that increased activity of the Src-JNK pathway in tumors inactivated Notch signaling because of JNK pathway-mediated inhibition of the expression of the gene encoding the Notch S2 cleavage protease, Kuzbanian, which is critical for Notch activity. Consequently, inactive Notch accumulated in cells, where it was unable to transcribe genes encoding its target proteins, many of which have tumor-suppressive activities. These findings suggest that Src-JNK activity in tumors predicts Notch activity status and that suppressing Src-JNK signaling could restore Notch function in tumors, offering opportunities for diagnosis and targeted therapies for a subset of patients with advanced prostate cancer.

JNK1 activated pRb/E2F1 and inhibited p53/p21 signaling pathway is involved in hydroquinone-induced pathway malignant transformation of TK6 cells by accelerating the cell cycle progression

Hydroquinone (HQ) is an important metabolites of benzene in the body, and it has been found to result in cellular DNA damage, mutation, cell cycle imbalance, and malignant transformation. The JNK1 signaling pathway plays an important role in DNA damage repair. In this study, we focused on whether the JNK1 signaling pathway is involved in the HQ-induced cell cycle abnormalities and the underlying mechanism. The results showed that HQ induced abnormal progression of the cell cycle and initiated the JNK1 signaling pathway. We further confirmed that JNK1 suppression decelerated the cell cycle progression through inhibiting pRb/E2F1 signaling pathway and triggering p53/p21 pathway. Therefore, we concluded that JNK1 might be involved in HQ-induced malignant transformation associated with activating pRb/E2F1 and inhibiting p53/p21 signaling pathway which resulting in accelerating the cell cycle progression.

Targeting SphK1/2 by SKI-178 inhibits prostate cancer cell growth

Sphingosine kinases (SphK), including SphK1 and SphK2, are important enzymes promoting progression of prostate cancer. SKI-178 is a novel and highly potent SphK1/2 dual inhibitor. We here tested the potential anti-prostate cancer cell activity of SKI-178. Bioinformatics analyses and results from local tissues demonstrated that that both SphK1 and SphK2 are upregulated in human prostate cancer tissues. Ectopic overexpression of SphK1 and SphK2, by lentiviral constructs, promoted primary prostate cancer cell proliferation and migration. In primary human prostate cancer cells and immortalized cell lines, SKI-178 potently inhibited cell viability, proliferation, cell cycle progression and cell migration, causing robust cell death and apoptosis. SKI-178 impaired mitochondrial functions, causing mitochondrial depolarization, reactive oxygen species production and ATP depletion.SKI-178 potently inhibited SphK activity and induced ceramide production, without affecting SphK1/2 expression in prostate cancer cells. Further, SKI-178 inhibited Akt-mTOR activation and induced JNK activation in prostate cancer cells. Contrarily, a constitutively-active Akt1 construct or the pharmacological JNK inhibitors attenuated SKI-178-induced cytotoxicity in prostate cancer cells. In vivo, daily intraperitoneal injection of a single dose of SKI-178 potently inhibited PC-3 xenograft growth in nude mice. SphK inhibition, ceramide production, ATP depletion and lipid peroxidation as well as Akt-mTOR inactivation and JNK activation were detected in PC-3 xenograft tissues with SKI-178 administration. Together, targeting SphK1/2 by SKI-178 potently inhibited prostate cancer cell growth in vitro and in vivo.

Sulforaphane Combined with Vitamin D Induces Cytotoxicity Mediated by Oxidative Stress, DNA Damage, Autophagy, and JNK/MAPK Pathway Modulation in Human Prostate Tumor Cells

Prostate cancer ranks second in incidence worldwide. To date, there are no available therapies to effectively treat advanced and metastatic prostate cancer. Sulforaphane and vitamin D alone are promising anticancer agents in vitro and in vivo, but their low bioavailability has limited their effects in clinical trials. The present study examined whether sulforaphane combined with vitamin D at clinically relevant concentrations improved the cytotoxicity of the compounds alone towards DU145 and PC-3 human prostate tumor cells. To assess the anticancer activity of this combination, we analyzed cell viability (MTT assay), oxidative stress (CM-H₂DCFDA), autophagy (fluorescence), DNA damage (comet assay), and protein expression (Western blot). The sulforaphane-vitamin D combination (i) decreased cell viability, induced oxidative stress, DNA damage, and autophagy, upregulated BAX, CASP8, CASP3, JNK, and NRF2 expression, and downregulated BCL2 expression in DU145 cells; and (ii) decreased cell viability, increased autophagy and oxidative stress, upregulated BAX and NRF2 expression, and downregulated JNK, CASP8, and BCL2 expression in PC-3 cells. Therefore, sulforaphane and vitamin D in combination have a potential application in prostate cancer therapy, and act to modulate the JNK/MAPK signaling pathway.

Glycyrrhetinic acid suppresses breast cancer metastasis by inhibiting M2-like macrophage polarization via activating JNK1/2 signaling

BACKGROUND

Breast cancer metastasis is leading cause of cancer death among women worldwide. Tumor-associated macrophages (TAMs) have been considered as potential targets for treating breast cancer metastasis because they promote tumor growth and development. Glycyrrhetinic acid (GA) is one of the most important phytochemicals of licorice which has shown promising anti-cancer efficacies in pre-clinical trials. However, the regulatory effect of GA on the polarization of TAMs remains elusive.

PURPOSE

To investigate the role of GA in regulating the polarization of M2 macrophages and inhibiting breast cancer metastasis, and to further explore its underlying mechanisms of action.

STUDY DESIGN

IL-4 / IL-13-treated RAW 264.7 and THP-1 cells were used as the M2-polarized macrophages in vitro. A 4T1 mouse breast cancer model and the tail vein breast cancer metastasis model were applied to study the effect of GA on breast cancer growth and metastasis in vivo.

RESULTS

In vitro studies showed that GA significantly inhibited IL-4 / IL 13-induced M2-like polarization in RAW 264.7 and THP-1 macrophages without affecting M1-like polarization. GA strongly decreased the expression of M2 macrophage markers CD206 and Arg-1, and reduced the levels of the pro-angiogenic molecules VEGF, MMP9, MMP2 and IL-10 in M2 macrophages. GA also increased the phosphorylation of JNK1/2 in M2 macrophages. Moreover, GA significantly suppressed M2 macrophage-induced cell proliferation and migration in 4T1 cancer cells and HUVECs. Interestingly, the inhibitory effects of GA on M2 macrophages were abolished by a JNK inhibitor. Animal studies showed that GA significantly suppressed tumor growth, angiogenesis, and lung metastasis in BALB/c mice bearing breast tumor. In tumor tissues, GA reduced the number of M2 macrophages but elevated the proportion of M1 macrophages, accompanied by activation of JNK signaling. Similar results were found in the tail vein breast cancer metastasis model.

CONCLUSION

This study demonstrated for the first time that GA could effectively suppress breast cancer growth and metastasis by inhibiting macrophage M2 polarization via activating JNK1/2 signaling. These findings indicate that GA could be served as the lead compound for the future development of anti-breast cancer drug.

Scutebarbatine A induces ROS-mediated DNA damage and apoptosis in breast cancer cells by modulating MAPK and EGFR/Akt signaling pathway

Scutebarbatine A (SBT-A), a diterpenoid alkaloid, has exerted cytotoxicity on hepatocellular carcinoma cells in our previous works. Here, the antitumor activity of SBT-A in breast cancer cells and the underlying mechanism were explored. The anti-proliferative effect of SBT-A was measured by trypan blue staining, 5-ethynyl-2'-deoxyuridine (EdU) incorporation and colony formation assay. DNA double-strand breaks (DSBs) were evaluated by observing the nuclear focus formation of γ-H2AX. Cell cycle distribution was assessed by flow cytometry. Apoptosis was determined by a TUNEL assay. Intracellular reactive oxygen species (ROS) generation and superoxide production were measured with 2', 7'-dichlorofluorescein diacetate (DCFH-DA) and dihydroethidium (DHE) staining, respectively. The results indicated that SBT-A showed a dose-dependent cytotoxic effect against breast cancer cells while revealing less toxicity toward MCF-10A breast epithelial cells. Moreover, SBT-A remarkably induced DNA damage, cell cycle arrest and apoptosis in both MDA-MB-231 and MCF-7 cells. SBT-A treatment increased the levels of ROS and cytosolic superoxide production. Pretreatment with N-acetyl cysteine (NAC), a ROS scavenger, was sufficient to block viability reduction, DNA damage, apoptosis and endoplasmic reticulum (ER) stress caused by SBT-A. By exposure to SBT-A, the phosphorylation of c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38MAPK) was upregulated, while the phosphorylation of extracellular signal-regulated kinase (ERK) was downregulated. In addition, SBT-A inhibited the EGFR signaling pathway by decreasing EGFR expression and phosphorylation of Akt and p70S6K. As mentioned above, SBT-A has a potent inhibitory effect on breast cancer cells through induction of DNA damage, apoptosis and ER stress via ROS generation and modulation of MAPK and EGFR/Akt signaling pathway.

Clostridium scindens metabolites trigger prostate cancer progression through androgen receptor signaling

Prostate cancer (PCa) is one of the most common malignancies in men; recently, PCa-related mortality has increased worldwide. Although androgen deprivation therapy (ADT) is the standard treatment for PCa, patients often develop aggressive castration-resistant PCa (CRPC), indicating the presence of an alternative source of androgen. Clostridium scindens is a member of the gut microbiota and can convert cortisol to 11β-hydroxyandrostenedione (11β-OHA), which is a potent androgen precursor. However, the effect of C. scindens on PCa progression has not been determined. In this study, androgen-dependent PCa cells (LNCaP) were employed to investigate whether C. scindens-derived metabolites activate androgen receptor (AR), which is a pivotal step in the development of PCa. Results showed that cortisol metabolites derived from C. scindens-conditioned medium promoted proliferation and enhanced migration of PCa cells. Furthermore, cells treated with these metabolites presented activated AR and stimulated AR-regulated genes. These findings reveal that C. scindens has the potential to promote PCa progression via the activation of AR signaling. Further studies on the gut-prostate axis may help unravel an alternative source of androgen that triggers CRPC exacerbation.

Adaptive and non-adaptive gene expression responses in prostate cancer during androgen deprivation

Androgen deprivation therapy is the cornerstone treatment of advanced prostate cancer. Eventually prostate cancer cells overcome androgen deprivation therapy, giving rise to castration resistant prostate cancer (CRPC) characterized by increased androgen receptor (AR) activity. Understanding the cellular mechanisms leading to CRPC is needed for development of novel treatments. We used long-term cell cultures to model CRPC; a testosterone-dependent cell line (VCaP-T) and cell line adapted to grow in low testosterone (VCaP-CT). These were used to uncover persistent and adaptive responses to testosterone level. RNA was sequenced to study AR-regulated genes. Expression level changed due to testosterone depletion in 418 genes in VCaP-T (AR-associated genes). To evaluate significance for CRPC growth, we compared which of them were adaptive i.e., restored expression level in VCaP-CT. Adaptive genes were enriched to steroid metabolism, immune response and lipid metabolism. The Cancer Genome Atlas Prostate Adenocarcinoma data were used to assess the association with cancer aggressiveness and progression-free survival. Expressions of 47 AR-associated or association gaining genes were statistically significant markers for progression-free survival. These included genes related to immune response, adhesion and transport. Taken together, we identified and clinically validated multiple genes being linked with progression of prostate cancer and propose several novel risk genes. Possible use as biomarkers or therapeutic targets should be studied further.

Cytotoxic N-Methylpretrichodermamide B Reveals Anticancer Activity and Inhibits P-Glycoprotein in Drug-Resistant Prostate Cancer Cells

N-methylpretrichodermamide B (NB) is a biologically active epidithiodiketopiperazine isolated from several strains of the algae-derived fungus Penicillium sp. Recently, we reported the first data on its activity in human cancer cells lines in vitro. Here, we investigated the activity, selectivity, and mechanism of action of NB in human prostate cancer cell lines, including drug-resistant subtypes. NB did not reveal cross-resistance to docetaxel in the PC3-DR cell line model and was highly active in hormone-independent 22Rv1 cells. NB-induced cell death was stipulated by externalization of phosphatidylserine and activation of caspase-3. Moreover, inhibition of caspase activity by z-VAD(OMe)-fmk did not affect NB cytotoxicity, suggesting a caspase-independent cell death induced by NB. The compound has a moderate p-glycoprotein (p-gp) substrate-like affinity and can simultaneously inhibit p-gp at nanomolar concentrations. Therefore, NB resensitized p-gp-overexpressing PC3-DR cells to docetaxel. A kinome profiling of the NB-treated cells revealed, among other things, an induction of mitogen-activated protein kinases JNK1/2 and p38. Further functional analysis confirmed an activation of both kinases and indicated a prosurvival role of this biological event in the cellular response to the treatment. Overall, NB holds promising anticancer potential and further structure-activity relationship studies and structural optimization are needed in order to improve its biological properties.

CARD14 Signalling Ensures Cell Survival and Cancer Associated Gene Expression in Prostate Cancer Cells

Prostate cancer (PCa) is one of the most common cancer types in men and represents an increasing global problem due to the modern Western lifestyle. The signalling adapter protein CARD14 is specifically expressed in epithelial cells, where it has been shown to mediate NF-κB signalling, but a role for CARD14 in carcinoma has not yet been described. By analysing existing cancer databases, we found that CARD14 overexpression strongly correlates with aggressive PCa in human patients. Moreover, we showed that CARD14 is overexpressed in the LNCaP PCa cell line and that knockdown of CARD14 severely reduces LNCaP cell survival. Similarly, knockdown of BCL10 and MALT1, which are known to form a signalling complex with CARD14, also induced LNCaP cell death. MALT1 is a paracaspase that mediates downstream signalling by acting as a scaffold, as well as a protease. Recent studies have already indicated a role for the scaffold function of MALT1 in PCa cell growth. Here, we also demonstrated constitutive MALT1 proteolytic activity in several PCa cell lines, leading to cleavage of A20 and CYLD. Inhibition of MALT1 protease activity did not affect PCa cell survival nor activation of NF-κB and JNK signalling, but reduced expression of cancer-associated genes, including the cytokine IL-6. Taken together, our results revealed a novel role for CARD14-induced signalling in regulating PCa cell survival and gene expression. The epithelial cell type-specific expression of CARD14 may offer novel opportunities for more specific therapeutic targeting approaches in PCa.

Pan-Cancer Analysis Reveals SH3TC2 as an Oncogene for Colorectal Cancer and Promotes Tumorigenesis via the MAPK Pathway

Simple Summary

SH3 domain and tetrapeptide repeat 2 (SH3TC2) is a protein-encoding gene and has previously been described as a critical signaling hub for neurological disorders, but no systematic analysis of SH3TC2 is available in cancer research. We analyzed SH3TC2 in various kinds of cancer to find its tumorigenic role in one or more specific cancers and further explored the mechanism of SH3TC2 in colorectal cancer (CRC). Our research revealed that higher expression of SH3TC2 indicated poor disease-free survival and promoted CRC progression and invasion via the MAPK signaling pathway.

Abstract

SH3 domain and tetrapeptide repeat 2 (SH3TC2) is a protein-encoding gene and has previously been described as a critical signaling hub for neurological disorders. Although increasing evidence supports a vital role of SH3TC2 in the tumorigenesis of various kinds of cancer, no systematic analysis of SH3TC2 is available. The function and mechanism of SH3TC2 in other cancers remain unknown. Thus, this study aimed to analyze SH3TC2 in various kinds of cancer to find its tumorigenic role in one or more specific cancers. In the current study, we analyzed the expression level and prognostic value of SH3TC2 in different tumors in the TCGA-GTEx pan-cancer dataset. Subsequently, the prognostic role and mechanism of SH3TC2 in colorectal cancer (CRC) were further explored via clinical samples and in vitro and in vivo experiments. We observed differential expression of SH3TC2 in colon adenocarcinoma (COAD), acute myeloid leukemia (LAML), READ (rectum adenocarcinoma), SKCM (skin cutaneous melanoma), and TGCT (testicular germ cell tumors). Subsequently, SH3TC2 showed a significant effect on the clinical stage and prognostic value in CRC, LAML, and SKCM. Moreover, we found in the TCGA database and seven GEO datasets that SH3TC2 was significantly highly expressed in tumor tissue. Through enrichment analysis of SH3TC2 and its co-expressed genes, we found that SH3TC2 may play a role in the MAPK signaling pathway. Correlation analysis indicated that SH3TC2 was significantly associated with multiple key factors in the MAPK signaling pathway. Additionally, higher expression of SH3TC2 was found in tumor tissue in our cohort including 40 CRC patients. Overexpression of SH3TC2 may imply poor prognosis. Knockdown of SH3TC2 significantly inhibited tumor invasion, migration, and proliferation. More importantly, knockdown of SH3TC2 inhibited tumor growth in a CRC mouse model. The study preliminarily conducted a pan-cancer study of SH3TC2 and further explored the mechanism of SH3TC2 in CRC. Our research revealed that higher expression of SH3TC2 may promote CRC progression and invasion via the MAPK signaling pathway.

WNT4 overexpression and secretion in thymic epithelial tumors drive an autocrine loop in tumor cells in vitro

Background

WNT4-driven non-canonical signaling is crucial for homeostasis and age-related involution of the thymus. Abnormal WNT signaling is important in many cancers, but the role of WNT signaling in thymic tumors is largely unknown.

Materials & Methods

Expression and function of WNT4 and FZD6 were analyzed using qRT–PCR, Western blot, ELISA, in biopsies of non-neoplastic thymi (NT), thymoma and thymic carcinomas. ShRNA techniques and functional assays were used in primary thymic epithelial cells (pTECs) and TC cell line 1889c. Cells were conventionally (2D) grown and in three-dimensional (3D) spheroids.

Results

In biopsy, WHO classified B3 thymomas and TCs showed increased WNT4 expression compared with NTs. During short-term 2D culture, WNT4 expression and secretion declined in neoplastic pTECs but not in 3D spheroids or medium supplemented with recombinant WNT4 cultures. Under the latter condition, the growth of pTECs was accompanied by increased expression of non-canonical targets RAC1 and JNK. Down-regulation of WNT4 by shRNA induced cell death in pTECs derived from B3 thymomas and led to decreased RAC1, but not JNK protein phosphorylation. Pharmacological inhibition of NF-κB decreased both RAC1 and JNK phosphorylation in neoplastic pTECs.

Conclusions

Lack of the age-related decline of non-canonical WNT4 expression in TETs and restoration of declining WNT4 expression through exogeneous WNT4 or 3D culture of pTECs hints at an oncogenic role of WNT4 in TETs and is compatible with the WNT4 autocrine loop model. Crosstalk between WNT4 and NF-κB signaling may present a promising target for combined interventions in TETs.

Synaptotagmin 11 scaffolds MKK7-JNK signaling process to promote stem-like molecular subtype gastric cancer oncogenesis

Background

Identifying biomarkers related to the diagnosis and treatment of gastric cancer (GC) has not made significant progress due to the heterogeneity of tumors. Genes involved in histological classification and genetic correlation studies are essential to develop an appropriate treatment for GC.

Methods

In vitro and in vivo lentiviral shRNA library screening was performed. The expression of Synaptotagmin (SYT11) in the tumor tissues of patients with GC was confirmed by performing Immunohistochemistry, and the correlation between the expression level and the patient’s survival rate was analyzed. Phospho-kinase array was performed to detect Jun N-terminal kinase (JNK) phosphorylation. SYT11, JNK, and MKK7 complex formation was confirmed by western blot and immunoprecipitation assays. We studied the effects of SYT11 on GC proliferation and metastasis, real-time cell image analysis, adhesion assay, invasion assay, spheroid formation, mouse xenograft assay, and liver metastasis.

Results

SYT11 is highly expressed in the stem-like molecular subtype of GC in transcriptome analysis of 527 patients with GC. Moreover, SYT11 is a potential prognostic biomarker for histologically classified diffuse-type GC. SYT11 functions as a scaffold protein, binding both MKK7 and JNK1 signaling molecules that play a role in JNK1 phosphorylation. In turn, JNK activation leads to a signaling cascade resulting in cJun activation and expression of downstream genes angiopoietin-like 2 (ANGPTL2), thrombospondin 4 (THBS4), Vimentin, and junctional adhesion molecule 3 (JAM3), which play a role in epithelial-mesenchymal transition (EMT). SNU484 cells infected with SYT11 shRNA (shSYT11) exhibited reduced spheroid formation, mouse tumor formation, and liver metastasis, suggesting a pro-oncogenic role of SYT11. Furthermore, SYT11-antisense oligonucleotide (ASO) displayed antitumor activity in our mouse xenograft model and was conferred an anti-proliferative effect in SNU484 and MKN1 cells.

Conclusion

SYT11 could be a potential therapeutic target as well as a prognostic biomarker in patients with diffuse-type GC, and SYT11-ASO could be used in therapeutic agent development for stem-like molecular subtype diffuse GC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02420-3.

Hexavalent chromium induces hepatocyte apoptosis via regulation of apoptosis signal-regulating kinase 1/c-Jun amino-terminal kinase signaling

With the spread of hexavalent chromium (Cr(VI)) contamination, Cr(VI)-induced hepatotoxicity has attracted increasing attention in recent years. To date, however, the exact mechanism of Cr(VI) toxicity remains unclear. In this study, we investigated the role of apoptosis signal-regulating kinase 1 (ASK1)/c-Jun amino-terminal kinase (JNK) in Cr(VI)-induced hepatic toxicity and the possible related mechanisms. AML-12 hepatocyte cell-lines were treated with 0, 1, 4, and 16 μmol/Lof Cr(VI) with or without GS-444271 (an ASK1 inhibitor). Adult male mice were administered with 0, 2, 8, and 32 mg/kg body mass (BM)/day of Cr(VI) for 5 days. The level of hepatocyte apoptosis/proliferation, generation of reactive oxygen species (ROS), and expression levels of mRNAs and proteins related to ASK1/JNK and nuclear factor-E2-related factor 2 (Nrf2) signaling were assessed. Results showed that high Cr(VI) exposure induced hepatocyte apoptosis and liver injury by generation of ROS and down-regulation of Nrf2 signaling. In addition, ASK1/JNK signaling activity was upregulated in the Cr(VI)-treated group. Furthermore, GS-444217 treatment significantly rescued Cr(VI)-induced hepatocyte apoptosis and liver dysfunction in vitro and in vivo by down-regulation of ASK1/JNK signaling. Thus, ASK1/JNK signaling appears to play an important role in Cr(VI)-induced hepatocyte apoptosis and liver injury. This study should help improve our understanding of the mechanism of Cr(VI)-induced liver injury and provide support for future investigations on liver disease therapy.

Oxidative Stress and Redox-Dependent Signaling in Prostate Cancer

Tumor emergence and progression is complicated by the dual role of reactive oxygen species (ROS). Low concentrations of ROS are essential for many intracellular metabolic processes and cell proliferation, while excessive ROS generation disrupts the mechanisms of cancer suppression, leading to the cell damage and death. A long-term imbalance in the ROS/antioxidant ratio and upregulation of the ROS generation due to the reduced efficacy of the antioxidant defense system cause chronic oxidative stress resulting in the damage of proteins, lipid, and DNA molecules and cancer development. Numerous data demonstrate that prostate cancer (the most common cancer in males) is associated with the development of oxidative stress. However, the reasons for the emergence of prostate cancer, as well as changes in the redox signaling and cellular redox homeostasis in this disease, are still poorly understood. The review examines the role of prooxidant and antioxidant enzyme systems, the imbalance in their activity leading to the oxidative stress development, changes in the key components of redox signaling, and the role of microRNAs in the modulation of redox status of cancer cells in prostate cancer.

Macrophages Cytokine Spp1 Increases Growth of Prostate Intraepithelial Neoplasia to Promote Prostate Tumor Progression

Prostate cancer development and progression are associated with increased infiltrating macrophages. Prostate cancer is derived from prostatic intraepithelial neoplasia (PIN) lesions. However, the effects macrophages have on PIN progression remain unclear. Here, we showed that the recruited macrophages adjacent to PIN expressed M2 macrophage markers. In addition, high levels of Spp1 transcripts, also known as osteopontin, were identified in these macrophages. Extraneously added Spp1 accelerated PIN cell proliferation through activation of Akt and JNK in a 3D culture setting. We also showed that PIN cells expressed CD44, integrin αv, integrin β1, and integrin β3, all of which have been previously reported as receptors for Spp1. Finally, blockade of Akt and JNK activation through their specific inhibitor completely abolished macrophage Spp1-induced cell proliferation of PIN. Hence, our data revealed Spp1 as another macrophage cytokine/growth factor and its mediated mechanism to upregulate PIN cell growth, thus promoting prostate cancer development.

Transcriptional CDK Inhibitors as Potential Treatment Option for Testicular Germ Cell Tumors

Simple Summary

Type II testicular germ cell tumors are a severe type of cancer in young men demanding alternative treatment options to conventional chemotherapy with less side effects. In particular, patients with chemotherapy-resistant tumors face a bad prognosis and low survival rates. In other tumor entities, transcriptional cyclin-dependent kinases (7/8/9/12/13) have been demonstrated to be effective targets. Here, we studied the effects of transcriptional cyclin-dependent kinase inhibitors on a cellular and molecular level. We found several inhibitors to be highly cytotoxic for certain testicular germ cell tumor cell lines while leaving a somatic (fibroblast) control cell line unaffected. This opens up a novel field for effective and specified treatment of type II testicular germ cell tumors.

Abstract

Type II testicular germ cell tumors (TGCT) are the most frequently diagnosed solid malignancy in young men. Up to 15% of patients with metastatic non-seminomas show cisplatin resistance and a very poor survival rate due to lacking treatment options. Transcriptional cyclin-dependent kinases (CDK) have been shown to be effective targets in the treatment of different types of cancer. Here, we investigated the effects of the CDK inhibitors dinaciclib, flavopiridol, YKL-5-124, THZ1, NVP2, SY0351 and THZ531. An XTT viability assay revealed a strong cytotoxic impact of CDK7/12/13 inhibitor SY0351 and CDK9 inhibitor NVP2 on the TGCT wild-type cell lines (2102EP, NCCIT, TCam2) and the cisplatin-resistant cell lines (2102EP-R, NCCIT-R). The CDK7 inhibitor YKL-5-124 showed a strong impact on 2102EP, 2102EP-R, NCCIT and NCCIT-R cell lines, leaving the MPAF control cell line mostly unaffected. FACS-based analysis revealed mild effects on the cell cycle of 2102EP and TCam2 cells after SY0351, YKL-5-124 or NVP2 treatment. Molecular analysis showed a cell-line-specific response for SY0351 and NVP2 inhibition while YKL-5-124 induced similar molecular changes in 2102EP, TCam2 and MPAF cells. Thus, after TGCT subtype determination, CDK inhibitors might be a potential alternative for optimized and individualized therapy independent of chemotherapy sensitivity.

Therapeutic approaches targeting CD95L/CD95 signaling in cancer and autoimmune diseases

Cell death plays a pivotal role in the maintenance of tissue homeostasis. Key players in the controlled induction of cell death are the Death Receptors (DR). CD95 is a prototypic DR activated by its cognate ligand CD95L triggering programmed cell death. As a consequence, alterations in the CD95/CD95L pathway have been involved in several disease conditions ranging from autoimmune diseases to inflammation and cancer. CD95L-induced cell death has multiple roles in the immune response since it constitutes one of the mechanisms by which cytotoxic lymphocytes kill their targets, but it is also involved in the process of turning off the immune response. Furthermore, beyond the canonical pro-death signals, CD95L, which can be membrane-bound or soluble, also induces non-apoptotic signaling that contributes to its tumor-promoting and pro-inflammatory roles. The intent of this review is to describe the role of CD95/CD95L in the pathophysiology of cancers, autoimmune diseases and chronic inflammation and to discuss recently patented and emerging therapeutic strategies that exploit/block the CD95/CD95L system in these diseases.

Surfactin induces ER stress-mediated apoptosis via IRE1-ASK1-JNK signaling in human osteosarcoma

Osteosarcoma, one of primary bone tumor in children and young adults, has poor prognosis and drug resistances to chemotherapy. In order to reinforce the conventional therapies and antagonize the osteosarcoma in patients, a novel strategy is required for developing a new treatment. In this study, surfactin, a natural product from Bacillus subtilis, showed the efficiency of cell death in osteosarcoma, but not in normal cells. Surfactin triggers ER stress mechanism by promoting the aberrant Ca²⁺ release from ER lumen and ER-signaling to mitochondrial dysfunction following caspases activation mediating cell apoptosis. Surfactin-induced ER stress not only upregulated of glucose-regulated protein 78/94 and IRE1-ASK1-JNK pathway but also leading to calpains and Bcl-2 proteins family involving the release of cytochrome c. The releases into cytosol trigger the cleavage of caspase-9 and caspase-3 to induce cell apoptosis. In this study, surfactin demonstrated the potential functions to trigger the ER stress, ER stress-associated IRE1-ASK1-JNK signaling pathway, mitochondrial dysfunction, and caspase activations leading to programmed cell apoptosis. Importantly, implicating the signaling pathway that regulates the connection between ER stress and mitochondrial dysfunction causing apoptosis associated with surfactin. These results indicated a potential application of surfactin strengthen current conventional therapies.

Targeting Protein Kinases and Epigenetic Control as Combinatorial Therapy Options for Advanced Prostate Cancer Treatment

Prostate cancer (PC), the fifth leading cause of cancer-related mortality worldwide, is known as metastatic bone cancer when it spreads to the bone. Although there is still no effective treatment for advanced/metastatic PC, awareness of the molecular events that contribute to PC progression has opened up opportunities and raised hopes for the development of new treatment strategies. Androgen deprivation and androgen-receptor-targeting therapies are two gold standard treatments for metastatic PC. However, acquired resistance to these treatments is a crucial challenge. Due to the role of protein kinases (PKs) in the growth, proliferation, and metastases of prostatic tumors, combinatorial therapy by PK inhibitors may help pave the way for metastatic PC treatment. Additionally, PC is known to have epigenetic involvement. Thus, understanding epigenetic pathways can help adopt another combinatorial treatment strategy. In this study, we reviewed the PKs that promote PC to advanced stages. We also summarized some PK inhibitors that may be used to treat advanced PC and we discussed the importance of epigenetic control in this cancer. We hope the information presented in this article will contribute to finding an effective treatment for the management of advanced PC.

Unraveling the Design and Discovery of c-Jun N-Terminal Kinase Inhibitors and Their Therapeutic Potential in Human Diseases

c-Jun N-terminal kinases (JNKs), members of the mitogen-activated protein kinase (MAPK) family, are encoded by three genes: jnk1, jnk2, and jnk3. JNKs are involved in the pathogenesis and development of many diseases, such as neurodegenerative diseases, inflammation, and cancers. Therefore, JNKs have become important therapeutic targets. Many JNK inhibitors have been discovered, and some have been introduced into clinical trials. However, the study of isoform-selective JNK inhibitors is still a challenging task. To further develop novel JNK inhibitors with clinical value, a comprehensive understanding of JNKs and their corresponding inhibitors is required. In this Perspective, we introduced the JNK signaling pathways and reviewed different chemical types of JNK inhibitors, focusing on their structure-activity relationships and biological activities. The challenges and strategies for the development of JNK inhibitors are also discussed. It is hoped that this Perspective will provide valuable references for the development of novel selective JNK inhibitors.

Functional Roles of JNK and p38 MAPK Signaling in Nasopharyngeal Carcinoma

c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK) family members integrate signals that affect proliferation, differentiation, survival, and migration in a cell context- and cell type-specific way. JNK and p38 MAPK activities are found upregulated in nasopharyngeal carcinoma (NPC). Studies have shown that activation of JNK and p38 MAPK signaling can promote NPC oncogenesis by mechanisms within the cancer cells and interactions with the tumor microenvironment. They regulate multiple transcription activities and contribute to tumor-promoting processes, ranging from cell proliferation to apoptosis, inflammation, metastasis, and angiogenesis. Current literature suggests that JNK and p38 MAPK activation may exert pro-tumorigenic functions in NPC, though the underlying mechanisms are not well documented and have yet to be fully explored. Here, we aim to provide a narrative review of JNK and p38 MAPK pathways in human cancers with a primary focus on NPC. We also discuss the potential therapeutic agents that could be used to target JNK and p38 MAPK signaling in NPC, along with perspectives for future works. We aim to inspire future studies further delineating JNK and p38 MAPK signaling in NPC oncogenesis which might offer important insights for better strategies in diagnosis, prognosis, and treatment decision-making in NPC patients.

A review of the biological role of miRNAs in prostate cancer suppression and progression

Prostate cancer (PC) is the third-leading cause of cancer-related deaths worldwide. Although the current treatment strategies are progressing rapidly, PC is still representing a substantial medical problem for affected patients. Several factors are involved in PC initiation, progression, and treatments failure including microRNAs (miRNAs). The miRNAs are endogenous short non-coding RNA sequence negatively regulating target mRNA expression via degradation or translation repression. miRNAs play a pivotal role in PC pathogenesis through its ability to initiate the induction of cancer stem cells (CSCs) and proliferation, as well as sustained cell cycle, evading apoptosis, invasion, angiogenesis, and metastasis. Furthermore, miRNAs regulate major molecular pathways affecting PC such as the androgen receptor (AR) pathway, p53 pathway, PTEN/PI3K/AKT pathway, and Wnt/β-catenin pathway. Furthermore, miRNAs alter PC therapeutic response towards the androgen deprivation therapy (ADT), chemotherapy and radiation therapy (RT). Thus, the understanding and profiling of the altered miRNAs expression in PC could be utilized as a non-invasive biomarker for the early diagnosis as well as for patient sub-grouping with different prognoses for individualized treatment. Accordingly, in the current review, we summarized in updated form the roles of various oncogenic and tumor suppressor (TS) miRNAs in PC, revealing their underlying molecular mechanisms in PC initiation and progression.

Dysregulated splicing factor SF3B1 unveils a dual therapeutic vulnerability to target pancreatic cancer cells and cancer stem cells with an anti-splicing drug

Background

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, requiring novel treatments to target both cancer cells and cancer stem cells (CSCs). Altered splicing is emerging as both a novel cancer hallmark and an attractive therapeutic target. The core splicing factor SF3B1 is heavily altered in cancer and can be inhibited by Pladienolide-B, but its actionability in PDAC is unknown. We explored the presence and role of SF3B1 in PDAC and interrogated its potential as an actionable target.

Methods

SF3B1 was analyzed in PDAC tissues, an RNA-seq dataset, and publicly available databases, examining associations with splicing alterations and key features/genes. Functional assays in PDAC cell lines and PDX-derived CSCs served to test Pladienolide-B treatment effects in vitro, and in vivo in zebrafish and mice.

Results

SF3B1 was overexpressed in human PDAC and associated with tumor grade and lymph-node involvement. SF3B1 levels closely associated with distinct splicing event profiles and expression of key PDAC players (KRAS, TP53). In PDAC cells, Pladienolide-B increased apoptosis and decreased multiple tumor-related features, including cell proliferation, migration, and colony/sphere formation, altering AKT and JNK signaling, and favoring proapoptotic splicing variants (BCL-XS/BCL-XL, KRASa/KRAS, Δ133TP53/TP53). Importantly, Pladienolide-B similarly impaired CSCs, reducing their stemness capacity and increasing their sensitivity to chemotherapy. Pladienolide-B also reduced PDAC/CSCs xenograft tumor growth in vivo in zebrafish and in mice.

Conclusion

SF3B1 overexpression represents a therapeutic vulnerability in PDAC, as altered splicing can be targeted with Pladienolide-B both in cancer cells and CSCs, paving the way for novel therapies for this lethal cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02153-9.

What Do We Have to Know about PD-L1 Expression in Prostate Cancer? A Systematic Literature Review. Part 3: PD-L1, Intracellular Signaling Pathways and Tumor Microenvironment

The tumor microenvironment (TME) includes immune (T, B, NK, dendritic), stromal, mesenchymal, endothelial, adipocytic cells, extracellular matrix, and cytokines/chemokines/soluble factors regulating various intracellular signaling pathways (ISP) in tumor cells. TME influences the survival/progression of prostate cancer (PC), enabling tumor cell immune-evasion also through the activation of the PD-1/PD-L1 axis. We have performed a systematic literature review according to the PRISMA guidelines, to investigate how the PD-1/PD-L1 pathway is influenced by TME and ISPs. Tumor immune-escape mechanisms include suppression/exhaustion of tumor infiltrating cytotoxic T lymphocytes, inhibition of tumor suppressive NK cells, increase in immune-suppressive immune cells (regulatory T, M2 macrophagic, myeloid-derived suppressor, dendritic, stromal, and adipocytic cells). IFN-γ (the most investigated factor), TGF-β, TNF-α, IL-6, IL-17, IL-15, IL-27, complement factor C5a, and other soluble molecules secreted by TME components (and sometimes increased in patients' serum), as well as and hypoxia, influenced the regulation of PD-L1. Experimental studies using human and mouse PC cell lines (derived from either androgen-sensitive or androgen-resistant tumors) revealed that the intracellular ERK/MEK, Akt-mTOR, NF-kB, WNT and JAK/STAT pathways were involved in PD-L1 upregulation in PC. Blocking the PD-1/PD-L1 signaling by using immunotherapy drugs can prevent tumor immune-escape, increasing the anti-tumor activity of immune cells.

Leelamine suppresses cMyc expression in prostate cancer cells in vitro and inhibits prostate carcinogenesis in vivo

Aim

Leelamine (LLM) inhibits growth of human prostate cancer cells but the underlying mechanism is not fully understood. The present study was undertaken to determine the effect of LLM on cMyc, which is overexpressed in a subset of human prostate cancers.

Methods

The effect of LLM on cMyc expression and activity was determined by western blotting/confocal microscopy and luciferase reporter assay, respectively. A transgenic mouse model of prostate cancer (Hi-Myc) was used to determine chemopreventive efficacy of LLM.

Results

Exposure of androgen sensitive (LNCaP) and castration-resistant (22Rv1) human prostate cancer cells to LLM resulted in downregulation of protein and mRNA levels of cMyc. Overexpression of cMyc partially attenuated LLM-mediated inhibition of colony formation, cell viability, and cell migration in 22Rv1 and/or PC-3 cells. LLM treatment decreased protein levels of cMyc targets (e.g., lactate dehydrogenase), however, overexpression of cMyc did not attenuate these effects. A trend for a decrease in expression level of cMyc protein was discernible in 22Rv1 xenografts from LLM-treated mice compared with control mice. The LLM treatment (10 mg/kg body weight, 5 times/week) was well-tolerated by Hi-Myc transgenic mice. The incidence of high-grade prostatic intraepithelial neoplasia, adenocarcinoma in situ, and microinvasion was lower in LLM-treated Hi-Myc mice but the difference was not statistically significant.

Conclusion

The present study reveals that LLM inhibits cMyc expression in human prostate cancer cells in vitro but concentrations higher than 10 mg/kg may be required to achieve chemoprevention of prostate cancer.

Targeting AP-1 transcription factors by CRISPR in the prostate

Prostate cancer is the second most diagnosed cancer in men. It is a slow progressing cancer, but when the disease reaches an advanced stage, treatment options are limited. Sequencing analyses of cancer samples have identified genes that can potentially drive disease progression. We implemented the CRISPR/Cas9 technology to simultaneously manipulate multiple genes in the murine prostate and thus to functionally test putative cancer driver genes in vivo. The activating protein-1 (AP-1) transcription factor is associated with many different cancer types, with the proto-oncogenes JUN and FOS being the two most intensely studied subunits. We analyzed expression of FOS and JUNB in human prostate cancer datasets and observed decreased expression in advanced stages. By applying CRISPR/Cas9 technology, the role of these two transcription factors in prostate cancer progression was functionally tested. Our data revealed that loss of either JunB or Fos in the context of Pten loss drives prostate cancer progression to invasive disease. Furthermore, loss of Fos increases Jun expression, and CRISPR inactivation of Jun in this context decreases cell proliferation. Overall, these in vivo studies reveal that JunB and Fos exhibit a tumor suppressor function by repressing invasive disease, whereas Jun is oncogenic and increases cell proliferation. This demonstrates that AP-1 factors are implicated in prostate cancer progression at different stages and display a dual function as tumor suppressor and as an oncogene in cancer progression.

Comparative Cytotoxic Activity of Hydroxytyrosol and Its Semisynthetic Lipophilic Derivatives in Prostate Cancer Cells

A high adherence to a Mediterranean diet has been related to numerous beneficial effects in human health, including a lower incidence and mortality of prostate cancer (PCa). Olive oil is an important source of phenolic bioactive compounds, mainly hydroxytyrosol (HT), of this diet. Because of the growing interest of this compound and its derivatives as a cancer chemopreventive agent, we aimed to compare the in vitro effect of HT isolated from olive mill wastewaters and five semisynthetic alkyl ether, ester, and nitro-derivatives against prostate cancer (PCa) cell lines. The effect in cell proliferation was determined in RWPE-1, LNCaP, 22Rv1, and PC-3 cells by resazurin assay, the effect in cell migration by wound healing assay, and tumorsphere and colony formation were evaluated. The changes in key signaling pathways involved in carcinogenesis were assessed by using a phosphorylation pathway profiling array and by Western blotting. Antiproliferative effects of HT and two lipophilic derivatives [hydroxytyrosyl acetate (HT-Ac)/ethyl hydroxytyrosyl ether (HT-Et)] were significantly higher in cancerous PC-3 and 22Rv1 cells than in non-malignant RWPE-1 cells. HT/HT-Ac/HT-Et significantly reduced migration capacity in RWPE-1 and PC-3 and prostatosphere size and colony formation in 22Rv1, whereas only HT-Ac and HT-Et reduced these functional parameters in PC-3. The cytotoxic effect in 22Rv1 cells was correlated with modifications in the phosphorylation pattern of key proteins, including ERK1/2 and AKT. Consistently, HT-Ac and HT-Et decreased p-AKT levels in PC-3. In sum, our results suggest that HT and its lipophilic derivatives could be considered as potential therapeutic tools in PCa.

Molecular mechanism underlying the apoptotic modulation by ethanol extract of Pseudolarix kaempferi in mucoepidermoid carcinoma of the salivary glands

Background

Pseudolarix kaempferi is a traditional Chinese natural product that possesses the potential cytotoxic effects against cancer. However, the precise molecular mechanism underlying its cytotoxic effects has not yet been completely elucidated. Here, we clarify the mechanism via which the ethanol extract of P. kaempferi (EEPK) leads to cytotoxicity mediated by apoptosis in mucoepidermoid carcinoma (MEC) originating from the salivary glands.

Methods

We investigated the mechanism underlying the anticancer efficacy of EEPK in human MEC in vitro by assessing mitochondrial dysfunction, mRNA levels, and morphological changes in apoptotic cell nuclei as well as by using a cytotoxicity assay, flow cytometric analysis, and western blotting.

Results

EEPK inhibited the growth of two human MEC cells and stimulated the induction of caspase-mediated apoptosis that was accompanied by mitochondrial membrane depolarization. Compared with the vehicle control groups, EEPK decreased myeloid cell leukemia-1 (Mcl-1) expression in both cells whereas it significantly decreased B cell lymphoma-2 (Bcl-2) expression in MC3 cells only. The EEPK-induced altered Mcl-1 expression was caused by translational inhibition and proteasomal degradation. Additionally, EEPK significantly increased p-Bcl-2 (Ser⁷⁰) expression regardless of its total forms by facilitating the activation of the c-Jun N-terminal kinase (JNK) signaling pathway, which exhibited cell context dependency. Nevertheless, JNK activation following EEPK treatment was, at least in part, required for the proapoptotic efficacy of EEPK in both cells.

Conclusions

This study revealed that EEPK-induced alterations of Mcl-1 inhibition and JNK/Bcl-2 phosphorylation cause apoptosis and provided basic preclinical data for future clinical trials regarding therapy for patients with MEC.

Graphic abstract

Targeting Farnesoid X receptor (FXR) for developing novel therapeutics against cancer

Cancer is one of the lethal diseases that arise due to the molecular alterations in the cell. One of those alterations associated with cancer corresponds to differential expression of Farnesoid X receptor (FXR), a nuclear receptor regulating bile, cholesterol homeostasis, lipid, and glucose metabolism. FXR is known to regulate several diseases, including cancer and cardiovascular diseases, the two highly reported causes of mortality globally. Recent studies have shown the association of FXR overexpression with cancer development and progression in different types of cancers of breast, lung, pancreas, and oesophagus. It has also been associated with tissue-specific and cell-specific roles in various cancers. It has been shown to modulate several cell-signalling pathways such as EGFR/ERK, NF-κB, p38/MAPK, PI3K/AKT, Wnt/β-catenin, and JAK/STAT along with their targets such as caspases, MMPs, cyclins; tumour suppressor proteins like p53, C/EBPβ, and p-Rb; various cytokines; EMT markers; and many more. Therefore, FXR has high potential as novel biomarkers for the diagnosis, prognosis, and therapy of cancer. Thus, the present review focuses on the diverse role of FXR in different cancers and its agonists and antagonists.

The Helicobacter pylori type IV secretion system upregulates epithelial cortactin expression by a CagA- and JNK-dependent pathway

Cortactin represents an important actin-binding factor, which controls actin-cytoskeletal remodelling in host cells. In this way, cortactin has been shown to exhibit crucial functions both for cell movement and tumour cell invasion. In addition, the cortactin gene cttn is amplified in various cancer types of humans. Helicobacter pylori is the causative agent of multiple gastric diseases and represents a significant risk factor for the development of gastric adenocarcinoma. It has been repeatedly shown that H. pylori manipulates cancer-related signal transduction events in infected gastric epithelial cells such as the phosphorylation status of cortactin. In fact, H. pylori modifies the activity of cortactin's binding partners to stimulate changes in the actin-cytoskeleton, cell adhesion and motility. Here we show that H. pylori infection of cultured AGS and Caco-2 cells for 24-48 hr leads to the overexpression of cortactin by 2-3 fold at the protein level. We demonstrate that this activity requires the integrity of the type IV secretion system (T4SS) encoded by the cag pathogenicity island (cagPAI) as well as the translocated effector protein CagA. We further show that ectopic expression of CagA is sufficient to stimulate cortactin overexpression. Furthermore, phosphorylation of CagA at the EPIYA-repeat region is not required, suggesting that this CagA activity proceeds in a phosphorylation-independent fashion. Inhibitor studies further demonstrate that the involved signalling pathway comprises the mitogen-activated protein kinase JNK (c-Jun N-terminal kinase), but not ERK1/2 or p38. Taken together, using H. pylori as a model system, this study discovered a previously unrecognised cortactin activation cascade by a microbial pathogen. We suggest that H. pylori targets cortactin to manipulate the cellular architecture and epithelial barrier functions that can impact gastric cancer development. TAKE AWAYS: Helicobacter pylori infection induces overexpression of cortactin at the protein level Cortactin upregulation requires the T4SS and effector protein CagA Ectopic expression of CagA is sufficient to stimulate cortactin overexpression Overexpression of cortactin proceeds CagA phosphorylation-independent The involved host cell signalling pathway comprises the MAP kinase JNK.

Helenalin Facilitates Reactive Oxygen Species-Mediated Apoptosis and Cell Cycle Arrest by Targeting Thioredoxin Reductase-1 in Human Prostate Cancer Cells

Background

Helenalin is a pseudoguaianolide natural product with anti-cancer activities. This study investigated the underlying mechanism of the anti-prostate cancer effects of helenalin in vitro.

Material/Methods

CCK-8 assay was performed to detect the optimal concentrations of helenalin in DU145 and PC-3 cells. After exposure to helenalin and/or reactive oxygen species (ROS) inhibitor, ROS production was assessed by DCFH-DA staining. Thioredoxin reductase-1 (TrxR1) expression was detected by RT-qPCR and western blot. Moreover, apoptosis and cell cycle were evaluated by flow cytometry. Following TrxR1 knockdown or overexpression, TrxR1 expression, ROS generation, apoptosis, cell cycle, migration, and invasion were examined in cells co-treated with helenalin.

Results

Helenalin distinctly repressed the viability of prostate cancer cells in a concentration-dependent manner. We chose 8 μM and 4 μM as the optimal concentrations of helenalin for DU145 and PC-3 cells, respectively. Helenalin treatment markedly triggered ROS production and lowered TrxR1 expression, which was ameliorated by ROS inhibitor. Exposure to helenalin facilitated apoptosis as well as G0/G1 cell cycle arrest, which was reversed by ROS inhibitor. Helenalin relieved the inhibitory effect of TrxR1 on ROS production. Furthermore, helenalin ameliorated the decrease in apoptosis rate and the shortening of G0/G1 phase as well as the increase in migration and invasion induced by TrxR1 overexpression.

Conclusions

Our findings revealed that helenalin accelerated ROS-mediated apoptosis and cell cycle arrest via targeting TrxR1 in human prostate cancer cells.

ZSCAN16-AS1 expedites hepatocellular carcinoma progression via modulating the miR-181c-5p/SPAG9 axis to activate the JNK pathway

Hepatocellular carcinoma (HCC) is generally known as one of the most common cancers in the world. Nowadays, interventional therapies such as transcatheter arterial chemoembolization (TACE) have emerged as an efficient therapy for HCC patients. Accumulating evidence has unveiled that long non-coding RNAs (lncRNAs) are crucial regulators in HCC progression. Nonetheless, the biological function of lncRNA zinc finger and SCAN domain containing 16 antisense RNA 1 (ZSCAN16-AS1) in HCC has not been systematically clarified. RT-qPCR was used to test ZSCAN16-AS1 expression in HCC cells. The biological functions of RP11-757 G1.5 on HCC cell proliferation, migration, invasion and apoptosis were investigated by colony formation, EdU, CCK-8 and transwell assays, as well as flow cytometry analysis. RNA immunoprecipitation (RIP), RNA pull-down and luciferase reporter assays were utilized to explore the specific mechanism of ZSCAN16-AS1. ZSCAN16-AS1 was significantly up-regulated in HCC cells. ZSCAN16-AS1 silence inhibited HCC cell proliferation, migration and invasion, while it accelerated HCC cell apoptosis. ZSCAN16-AS1 worked as a competing endogenous RNA (ceRNA) to regulate sperm associated antigen 9 (SPAG9) expression through sponging miR-181 c-5p. Moreover, SPAG9 could activate the c-Jun-N-terminal kinase (JNK) pathway. Taken together, our study elucidated that ZSCAN16-AS1 expedited HCC progression via modulating the miR-181 c-5p/SPAG9 axis to activate the JNK pathway, which might be a highly potential HCC therapy and treatment target.

Novel Single Inhibitor of HDAC6/8 and Dual Inhibitor of PI3K/HDAC6 as Potential Alternative Treatments for Prostate Cancer

Background: Prostate cancer is the second most frequently diagnosed malignancy worldwide. Here, the cytotoxic and antimetastatic effects of a new HDAC6/8 inhibitor, LASSBio-1911, and a new dual-PI3K/HDAC6 inhibitor, LASSBio-2208, were evaluated against PC3 prostate cancer cell line. Methods: A MTT assay was used to assess the cell viability. Annexin V/propidium iodide (PI) was used to detect apoptotic cell death and to analyze the cell cycle distribution. Interleukin 6 (IL-6) levels were measured by ELISA. A cell scratch assay was performed to assess cell migration, and the expression of proteins was estimated by Western blotting. Results: LASSBio-1911 and LASSBio-2208 exert cytotoxic effects against PC3 cells. However, LASSBio-2208 was demonstrated to be more potent than LASSBio-1911. The apoptosis assays showed that both compounds trigger apoptotic processes and cause the arrest of cells in the G2/M phase of the cell cycle. The Western blot analysis revealed that LASSBio-2208 significantly decreased the expression of p-JNK and JAK2. However, both compounds reduced the expression of p-STAT3, IL-6 secretion, and cell migration. Conclusions: LASSBio-1911 and LASSBio-2208 demonstrated significant activity in reducing cell viability and migration. These compounds can be further used as prototypes for the development of new potential anticancer alternative treatments.

Pathophysiological Significance of WDR62 and JNK Signaling in Human Diseases

The c-Jun N-terminal kinase (JNK) is highly evolutionarily conserved and plays important roles in a broad range of physiological and pathological processes. The WD40-repeat protein 62 (WDR62) is a scaffold protein that recruits different components of the JNK signaling pathway to regulate several human diseases including neurological disorders, infertility, and tumorigenesis. Recent studies revealed that WDR62 regulates the process of neural stem cell mitosis and germ cell meiosis through JNK signaling. In this review we summarize the roles of WDR62 and JNK signaling in neuronal and non-neuronal contexts and discuss how JNK-dependent signaling regulates both processes. WDR62 is involved in various human disorders via JNK signaling regulation, and may represent a promising therapeutic strategy for the treatment of related diseases.

Nuclear overexpression levels of MAGE-A3 predict poor prognosis in patients with prostate cancer

Melanoma antigen gene A3 (MAGE-A3) is one of the most immunogenic cancer testis antigens and is common in various types of cancers. In this study, for the first time, we performed immunohistochemical analysis to evaluate the expression of MAGE-A3 in 153 prostate tissue samples including prostate cancer (PCa), benign prostatic hyperplasia (BPH), and high-grade prostatic intraepithelial neoplasia (HPIN). Increased both nuclear and cytoplasmic expression of MAGE-A3 was significantly found in PCa tissues compared with both HPIN and BPH tissues (nuclear expression at p = 0.011, and cytoplasmic expression at p = 0.034; for both comparisons p < 0.0001, respectively). A significant correlation was observed between higher nuclear and cytoplasmic expressions of MAGE-A3 with Gleason score (p < 0.0001 and 0.006, respectively). Increased expression of MAGE-A3 was associated with shorter biochemical recurrence-free survival (BCR-FS) and disease-free survival (DFS) of patients (p = 0.042 and = 0.0001, respectively). In multivariate analysis, nuclear expression of MAGE-A3 and Gleason score (≤7 vs >7) was independent predictors of the DFS (both; p = 0.019). Nuclear expression of MAGE-A3 was also significantly related to BCR-FS (p = 0.015). MAGE-A3 can be considered as a predictor for poor prognosis and an option for vaccine immunotherapy in patients with PCa.

Antioxidant/pro-oxidant and antiproliferative activities of phenolic-rich foods and extracts: A cell-based point of view

Phenolic compounds have demonstrated several in vitro beneficial properties by acting as antioxidant and pro-oxidant agents. This chapter approaches the relationship among oxidative stress, cancer, phenolic compounds and antiproliferative activity. Moreover, it discusses in vitro techniques and their biological applications, regarding cell viability and intracellular measure of reactive oxygen assays. The in vitro methods are important tools for screening and understanding the pathways involved on antiproliferative and antioxidant/pro-oxidant effects of phenolic compounds. These findings open avenues for the development of innovative food, chemical structures, technological applications and future perspectives in this research field.

The Prognostic Significance of Anisomycin-Activated Phospho-c-Jun NH2-Terminal Kinase (p-JNK) in Predicting Breast Cancer Patients' Survival Time

This study aims to investigate the prognostic significance of p-JNK in breast cancer patients receiving neoadjuvant chemotherapy (NACT) and analyze the relationship between anisomycin, p-JNK. A total of 104 breast cancer patients had NACT were enrolled in this study. The western blot and immunohistochemistry assays were used to determine the protein expressions of p-JNK in human breast cancer cell lines and patients’ cancer tissues. The chi-square test and Fisher’s exact test were adopted to gauge the associations between breast cancer and clinicopathological variables by p-JNK expression, whereas the univariate and multivariate Cox proportional hazards regression models were used to analyze the prognostic value of p-JNK expression. The Kaplan-Meier plots and the log-rank test were adopted to determine patients’ disease-free survival (DFS) and overall survival (OS). Findings indicated that the p-JNK expression had prognostic significance in univariate and multivariate Cox regression survival analyses. Results of log-rank methods showed that: (1) the mean DFS and OS times in patients with high p-JNK expression were significantly longer than those in patients with low p-JNK expression (χ² = 5.908, P = 0.015 and χ² = 6.593, P = 0.010, respectively). p-JNK expression is a significant prognostic factor that can effectively predict the survival in breast cancer patients receiving NACT. Treatment with the JNK agonist anisomycin can induce apoptosis, lead to increased p-JNK expression and decreased p-STAT3 expression. Moreover, the p-JNK expression was inversely correlated with p-STAT3 expression.

Downregulation of Snail by DUSP1 Impairs Cell Migration and Invasion through the Inactivation of JNK and ERK and Is Useful as a Predictive Factor in the Prognosis of Prostate Cancer

Dual specificity phosphatase 1 (DUSP1) is crucial in prostate cancer (PC), since its expression is downregulated in advanced carcinomas. Here, we investigated DUSP1 effects on the expression of mesenchymal marker Snail, cell migration and invasion, analyzing the underlying mechanisms mediated by mitogen-activated protein kinases (MAPKs) inhibition. To this purpose, we used different PC cells overexpressing or lacking DUSP1 or incubated with MAPKs inhibitors. Moreover, we addressed the correlation of DUSP1 expression with Snail and activated MAPKs levels in samples from patients diagnosed with benign hyperplasia or prostate carcinoma, studying its implication in tumor prognosis and survival. We found that DUSP1 downregulates Snail expression and impairs migration and invasion in PC cells. Similar results were obtained following the inhibition of c-Jun N-terminal kinase (JNK) and extracellular-signal-regulated kinase (ERK). In clinical samples, we evidenced an inverse correlation between DUSP1 expression and Snail levels, which are further associated with JNK and ERK activation. Consequently, the pattern DUSP1_high/activated JNK_low/activated ERK_low/Snail_low is associated with an overall extended survival of PC patients. In summary, the ratio between DUSP1 and Snail expression, with additional JNK and ERK activity measurement, may serve as a potential biomarker to predict the clinical outcome of PC patients. Furthermore, DUSP1 induction or inhibition of JNK and ERK pathways could be useful to treat PC.

In vivo CRISPR inactivation of Fos promotes prostate cancer progression by altering the associated AP-1 subunit Jun

Prostate cancer is a major global health concern with limited treatment options for advanced disease. Its heterogeneity challenges the identification of crucial driver genes implicated in disease progression. Activating protein-1 (AP-1) transcription factor is associated with cancer since the first identification of its subunits, the proto-oncogenes JUN and FOS. Whereas both JUN and FOS, have been implicated in prostate cancer, this study provides the first functional evidence that FOS acts as a tumor suppressor during prostate cancer progression and invasion. Data mining revealed decreased FOS expression in prostate cancer and a further downregulation in metastatic disease, consistent with FOS expression in cell lines derived from different prostate cancer stages. FOS deficiency in prostate cancer cell lines increases cell proliferation and induces oncogenic pathway alterations. Importantly, in vivo CRISPR/Cas9-mediated Fos and Pten double mutation in murine prostate epithelium results in increased proliferation and invasiveness compared to the abrogation of Pten alone. Interestingly, enhanced Jun expression is observed in the murine prostatic intraepithelial neoplasia lacking Fos. CRISPR/Cas9-mediated knockout of Jun combined with Fos and Pten deficiency diminishes the increased proliferation rate in vivo, but not the ability to form invasive disease. Overall, we demonstrate that loss of Fos promotes disease progression from clinical latent prostate cancer to advanced disease through accelerated proliferation and invasiveness, partly through Jun.

Anti-Metastatic and Anti-Inflammatory Effects of Matrix Metalloproteinase Inhibition by Ginsenosides

Matrix metalloproteinases (MMPs) are proteolytic enzymes which cleave extracellular matrix (ECM) and other substrates. They are deeply involved in both cancer metastasis and human chronic inflammatory diseases such as osteoarthritis and Crohn’s disease. Regulation of MMPs is closely associated with signaling molecules, especially mitogen-activated protein kinases (MAPKs), including three representative kinases, extracellular signal regulated kinases (ERK), p38 and c-Jun N-terminal kinases (JNK). Ginseng (Panax sp.) is a plant which has been traditionally used for medicinal applications. Ginsenosides are major metabolites which have potentials to treat various human diseases. In this review, the pharmacological effects of ginsenosides have been rigorously investigated; these include anti-metastatic and anti-inflammatory activities of ginsenosides associated with suppression of MMPs via regulation of various signaling pathways. This will highlight the importance of MMPs as therapeutic targets for anti-metastatic and anti-inflammatory drug development based on ginsenosides.

Post-Translational Modifications That Drive Prostate Cancer Progression

While a protein primary structure is determined by genetic code, its specific functional form is mostly achieved in a dynamic interplay that includes actions of many enzymes involved in post-translational modifications. This versatile repertoire is widely used by cells to direct their response to external stimuli, regulate transcription and protein localization and to keep proteostasis. Herein, post-translational modifications with evident potency to drive prostate cancer are explored. A comprehensive list of proteome-wide and single protein post-translational modifications and their involvement in phenotypic outcomes is presented. Specifically, the data on phosphorylation, glycosylation, ubiquitination, SUMOylation, acetylation, and lipidation in prostate cancer and the enzymes involved are collected. This type of knowledge is especially valuable in cases when cancer cells do not differ in the expression or mutational status of a protein, but its differential activity is regulated on the level of post-translational modifications. Since their driving roles in prostate cancer, post-translational modifications are widely studied in attempts to advance prostate cancer treatment. Current strategies that exploit the potential of post-translational modifications in prostate cancer therapy are presented.