Shikonin attenuates lung cancer cell adhesion to extracellular matrix and metastasis by inhibiting integrin β1 expression and the ERK1/2 signaling pathway

Dual folate/biotin-decorated liposomes mediated delivery of methylnaphthazarin for anti-cancer activity

Chemotherapy is an effective strategy for mitigating the global challenge of cancer treatment, which often encounters drug resistance and negative side effects. Methylnaphthazarin (MNZ), a natural compound with promising anti-cancer properties, has been underexplored due to its poor aqueous solubility and low selectivity. This study introduces a novel approach to overcome these limitations by developing MNZ-encapsulating liposomes decorated with folate and biotin (F/B-LP-MNZ). This dual-targeting strategy aims to enhance the anti-cancer efficacy and specificity of MNZ delivery. Our innovative F/B-LP-MNZ formulation demonstrated excellent physicochemical properties, stability, and controlled drug release profiles. In vitro studies revealed that MNZ-loaded liposomes attenuate the toxicity associated with free MNZ while F/B-LP-MNZ significantly increased cytotoxicity against HeLa cells, which express high levels of folate and biotin receptors, compared to non-targeted liposomes. Enhanced cellular uptake and improved dynamic flow attachment further confirmed the superior specificity of F/B-LP in targeting cancer cells. Additionally, our results revealed that F/B-LP-MNZ effectively inhibits HeLa cell migration and adhesion through EMT suppression and apoptotic induction, indicating its potential to prevent cancer metastasis. These findings highlight the potential of dual folate and biotin receptors-targeting liposomes as an effective delivery system for MNZ, offering a promising new avenue for targeted cancer therapy.

Attenuation of PI3K-Akt-mTOR Pathway to Reduce Cancer Stemness on Chemoresistant Lung Cancer Cells by Shikonin and Synergy with BEZ235 Inhibitor

Lung cancer is considered the number one cause of cancer-related deaths worldwide. Although current treatments initially reduce the lung cancer burden, relapse occurs in most cases; the major causes of mortality are drug resistance and cancer stemness. Recent investigations have provided evidence that shikonin generates various bioactivities related to the treatment of cancer. We used shikonin to treat multi-resistant non-small lung cancer cells (DOC-resistant A549/D16, VCR-resistant A549/V16 cells) and defined the anti-cancer efficacy of shikonin. Our results showed shikonin induces apoptosis in these ABCB1-dependent and independent chemoresistance cancer sublines. Furthermore, we found that low doses of shikonin inhibit the proliferation of lung cancer stem-like cells by inhibiting spheroid formation. Concomitantly, the mRNA level and protein of stemness genes (Nanog and Oct4) were repressed significantly on both sublines. Shikonin reduces the phosphorylated Akt and p70s6k levels, indicating that the PI3K/Akt/mTOR signaling pathway is downregulated by shikonin. We further applied several signaling pathway inhibitors that have been used in anti-cancer clinical trials to test whether shikonin is suitable as a sensitizer for various signaling pathway inhibitors. In these experiments, we found that low doses shikonin and dual PI3K-mTOR inhibitor (BEZ235) have a synergistic effect that inhibits the spheroid formation from chemoresistant lung cancer sublines. Inhibiting the proliferation of lung cancer stem cells is believed to reduce the recurrence of lung cancer; therefore, shikonin's anti-drug resistance and anti-cancer stem cell activities make it a highly interesting molecule for future combined lung cancer therapy.

Luteolin inhibits angiogenesis and enhances radiotherapy sensitivity of laryngeal cancer via downregulating Integrin β1

AIM

To demonstrate the role and mechanism of luteolin in radio-sensitization and angiogenesis of laryngeal cancer.

METHODS

Firstly, we analyzed the cytotoxicity of Luteolin and radiation sensitive cytotoxicity through CCK8, and selected subsequent radiation doses and Luteolin concentrations. Next, we further analyzed the effects of Luteolin on radiation sensitivity and neovascularization of laryngeal cancer, and conducted CCK8, plate cloning, and angiogenesis experiments, respectively. At the same time, the effects of individual treatment and combination treatment on the expression of Integrin β1 and VEGFA were analyzed through immunofluorescence analysis. We also analyzed the regulation of Integrin β1 protein expression by Luteolin through Western blot. To investigate the mechanism of Integrin β1, we transfected overexpressed and silenced Integrin β1 vectors and analyzed the role of Integrin β1 in Luteolin enhancing radiation sensitivity of laryngeal cancer by repeating the above experiments. We have also constructed an in vivo subcutaneous tumor transplantation model to further validate the cell experimental results. The expression of Integrin, KI67, VEGFA, and CD31 was analyzed through Western blot and immunohistochemistry experiments.

RESULTS

Radiation inhibited cell proliferation and decreased Integrin β1 expression, and increased the radiosensitivity through inhibiting cell proliferation, and inhibit angiogenesis during radiation. Overexpression of Integrin β1 weakened radiotherapy sensitivity on the basis of cells treated with combined administration. Integrin β1 is considered as the downstream molecule of luteolin, participating in radiosensitivity of luteolin to FaDu cells. Animal experiments also demonstrated that luteolin strengthened tumor suppression and anti-angiogenesis during radiation via Integrin β1.

CONCLUSION

In summary, our results manifested that radio-sensitivity effect of luteolin depended on downregulating Integrin β1 in laryngocarcinoma.

Promising Nanomedicines of Shikonin for Cancer Therapy

Malignant tumor, the leading cause of death worldwide, poses a serious threat to human health. For decades, natural product has been proven to be an essential source for novel anticancer drug discovery. Shikonin (SHK), a natural molecule separated from the root of Lithospermum erythrorhizon, shows great potential in anticancer therapy. However, its further clinical application is significantly restricted by poor bioavailability, adverse effects, and non-selective toxicity. With the development of nanotechnology, nano drug delivery systems have emerged as promising strategies to improve bioavailability and enhance the therapeutic efficacy of drugs. To overcome the shortcoming of SHK, various nano drug delivery systems such as liposomes, polymeric micelles, nanoparticles, nanogels, and nanoemulsions, were developed to achieve efficient delivery for enhanced antitumor effects. Herein, this review summarizes the anticancer pharmacological activities and pharmacokinetics of SHK. Additionally, the latest progress of SHK nanomedicines in cancer therapy is outlined, focusing on long circulation, tumor targeting ability, tumor microenvironment responsive drug release, and nanosystem-mediated combination therapy. Finally, the challenges and prospects of SHK nanomedicines in the future clinical application are spotlighted.

Shikonin Promotes Apoptosis and Attenuates Migration and Invasion of Human Esophageal Cancer Cells by Inhibiting Tumor Necrosis Factor Receptor-Associated Protein 1 Expression and AKT/mTOR Signaling Pathway

The aim of this study was to investigate the anticancer effects of shikonin on esophageal cancer (EC) cells and explore the underlying molecular mechanism by identifying dysregulation in shikonin-induced tumor necrosis factor receptor-associated protein 1 (TRAP1) expression. The 3-(4, 5-dimethylthiazol-2-Yl)-2, 5-diphenyltetrazolium bromide assay and EDU assay were performed for cell viability determination. The reactive oxygen species level and mitochondrial membrane potential were evaluated using flow cytometry. The protein expression was detected using Western blot. In addition, cell migration and invasion were estimated. These results demonstrated that shikonin inhibited EC cell growth in a concentration-dependent manner and induced apoptosis through activation of the intracellular apoptotic signaling pathway. Moreover, TRAP1 downregulation promoted shikonin-induced reactive oxygen species release, whereas TRAP1 upregulation blocked it. Meanwhile, shikonin significantly promoted mitochondrial depolarization, accompanied by a large release of cytochrome C. Conversely, shikonin significantly decreased adenosine 5'-triphosphate release, demonstrating a significant intervention in the process of the glucose metabolism. In addition, not only shikonin but also short hairpin RNA (shRNA)-TRAP1 inhibited EC cell migration and invasion. shRNA-TRAP1 enhanced the inhibitory effect of shikonin on matrix metalloproteinase (MMP)2 and MMP9 expression. More interestingly, we demonstrated that shRNA-TRAP1 played a synergistic role in shikonin-mediated regulation of protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling. Collectively, shikonin promoted apoptosis and attenuated migration and invasion of EC cells by inhibiting TRAP1 expression and AKT/mTOR signaling, indicating that shikonin may be a new drug for treating EC.

Targeting pyruvate kinase muscle isoform 2 (PKM2) in cancer: What do we know so far?

Cancer is a leading cause of death globally. Cancer cell transformation is the result of intricate crosstalk between intracellular components and proteins. A characteristic feature of cancer cells is the ability to reprogram their metabolic pathways to ensure their infinite proliferative potential. Pyruvate kinase muscle isoform 2 (PKM2) is a glycolytic enzyme that plays crucial roles in cancer, apart from carrying out its metabolic roles. PKM2 is involved in all the major events associated with cancer growth. Modulation of PKM2 activity (dimer inhibition or tetramer activation) has been successful in controlling cancer. However, recent studies provide contrary evidences regarding the oncogenic functions of PKM2. Moreover, several studies have highlighted the cancerous roles of PKM1 isoform in certain contexts. The present review aims at providing the current updates regarding PKM2 targeting in cancer. Further, the review discusses the contradictory results that suggest that both the isoforms of PKM can lead to cancer growth. In conclusion, the review emphasizes revisiting the approaches to target cancer metabolism through PKM to find novel and effective targets for anticancer therapy.

Role of the APRIL molecule in solid tumors

The APRIL molecule, produced by immune cells, their precursors, and cancer cells, is one of the important factors that influences the process of survival and proliferation of cancer cells. In the present review, we summarize the current knowledge on the effects of APRIL on human cancer development and develop a scheme demonstrating the mechanism of the action of APRIL on solid tumors. Understanding the effects of APRIL, including the intracellular signal transduction pathway, may be key for the use of this protein as a biomarker of the cancer process. The correlations observed between APRIL levels and cancer parameters (e.g., disease stage and presence of malignant phenotypes) indicate that APRIL may play an important role, not only in the diagnostic process, but also as a therapeutic target in various cancers.

Co-targeting PI3K/Akt and MAPK/ERK pathways leads to an enhanced antitumor effect on human hypopharyngeal squamous cell carcinoma

PURPOSE

The present study aims to determine whether co-targeting PI3K/Akt and MAPK/ERK pathways in human hypopharyngeal squamous cell carcinoma (HSCC) is a potential anticancer strategy.

METHODS

We retrospectively analyzed the clinical data of HSCC patients, and the phosphorylation status of Akt and Erk in HSCC and tumor adjacent tissues was evaluated by immunohistochemistry. MTT and colony formation assay were performed to determine the anti-proliferative effect of PI3K/mTOR inhibitor GDC-0980 and MEK inhibitor Refametinib on HSCC cell line Fadu. Wound-healing and Transwell migration assay were used to analyze the anti-migrative capability of the two drugs. The involved anti-tumor mechanism was explored by flow cytometry, qRT-PCR and western blot. The combinational anticancer effect of GDC-0980 and Refametinib was evaluated according to Chou and Talalay's method.

RESULTS

The levels of p-Akt and p-Erk were increased significantly with the progression of clinical stage of HSCC, suggesting PI3K/Akt and MAPK/ERK pathways might be associated with HSCC occurrence and progression. Furthermore, both GDC-0980 and Refametinib showed obvious antitumor effects on FaDu cells. Treatment by the two drugs arrested FaDu cell cycle progression in G1 phase, with reduction of cyclin D1 and p-Rb, in contrast to enhancement of p27. GDC-0980 inhibited FaDu cell migration and reduced metastasis related proteins including p-PKCζ, p-Integrin β1 and uPA. Combination use of GDC-0980 and Refametinib exhibited strong synergistic anti-tumor effect.

CONCLUSION

Dual inhibition of PI3K/Akt and MAPK/ERK pathway by GDC-0980 and Refametinib might be a promising treatment strategy for HSCC patients.

Naturally occurring anti-cancer compounds: shining from Chinese herbal medicine

Numerous natural products originated from Chinese herbal medicine exhibit anti-cancer activities, including anti-proliferative, pro-apoptotic, anti-metastatic, anti-angiogenic effects, as well as regulate autophagy, reverse multidrug resistance, balance immunity, and enhance chemotherapy in vitro and in vivo. To provide new insights into the critical path ahead, we systemically reviewed the most recent advances (reported since 2011) on the key compounds with anti-cancer effects derived from Chinese herbal medicine (curcumin, epigallocatechin gallate, berberine, artemisinin, ginsenoside Rg3, ursolic acid, silibinin, emodin, triptolide, cucurbitacin B, tanshinone I, oridonin, shikonin, gambogic acid, artesunate, wogonin, β-elemene, and cepharanthine) in scientific databases (PubMed, Web of Science, Medline, Scopus, and Clinical Trials). With a broader perspective, we focused on their recently discovered and/or investigated pharmacological effects, novel mechanism of action, relevant clinical studies, and their innovative applications in combined therapy and immunomodulation. In addition, the present review has extended to describe other promising compounds including dihydroartemisinin, ginsenoside Rh2, compound K, cucurbitacins D, E, I, tanshinone IIA and cryptotanshinone in view of their potentials in cancer therapy. Up to now, the evidence about the immunomodulatory effects and clinical trials of natural anti-cancer compounds from Chinese herbal medicine is very limited, and further research is needed to monitor their immunoregulatory effects and explore their mechanisms of action as modulators of immune checkpoints.

Pharmacological properties and derivatives of shikonin-A review in recent years

Shikonin is the major bioactive component extracted from the roots of Lithospermum erythrorhizon which is also known as "Zicao" in Traditional Chinese Medicine (TCM). Recent studies have shown that shikonin demonstrates various bioactivities related to the treatment of cancer, inflammation, and wound healing. This review aimed to provide an updated summary of recent studies on shikonin. Firstly, many studies have demonstrated that shikonin exerts strong anticancer effects on various types of cancer by inhibiting cell proliferation and migration, inducing apoptosis, autophagy, and necroptosis. Shikonin also triggers Reactive Oxygen Species (ROS) generation, suppressing exosome release, and activate anti-tumor immunity in multiple molecular mechanisms. Examples of these effects include modulating the PI3K/AKT/mTOR and MAPKs signaling; inhibiting the activation of TrxR1, PKM2, RIP1/3, Src, and FAK; and regulating the expression of ERP57, MMPs, ATF2, C-MYC, miR-128, and GRP78 (Bip). Next, the anti-inflammatory and wound-healing properties of shikonin were also reviewed. Furthermore, several studies focusing on shikonin derivatives were reviewed, and these showed that, with modification to the naphthazarin ring or side chain, some shikonin derivatives display stronger anticancer activity and lower toxicity than shikonin itself. Our findings suggest that shikonin and its derivatives could serve as potential novel drug for the treatment of cancer and inflammation.

MicroRNA‑208a directly targets Src kinase signaling inhibitor 1 to facilitate cell proliferation and invasion in non‑small cell lung cancer

The abnormal expression of microRNAs (miRNAs/miRs) has a critical function in the formation and progression of non-small cell lung cancer (NSCLC). Therefore, understanding the association between NSCLC and dysregulated miRNAs may allow for the identification of novel diagnostic and therapeutic biomarkers for patients with this malignancy. Previous studies have validated miR-208a as a cancer-associated miRNA in multiple different types of human cancer, however, its expression pattern and precise function in NSCLC remains yet to be elucidated. Therefore, the aims of the present study were to measure miR-208a expression in NSCLC, investigate its specific functions in NSCLC and determine its exact regulatory mechanisms. Herein, the results demonstrated that miR-208a was significantly upregulated in NSCLC tissues and cell lines compared with that in adjacent non-cancerous tissues and a non-tumorigenic bronchial epithelium BEAS-2B cell line (P<0.05, respectively). The high expression level of miR-208a exhibited an obvious association with Tumor-Node-Metastasis stage and lymph node metastasis. miR-208a silencing decreased the proliferative and invasive capacities of NSCLC cells. Notably, Src kinase signaling inhibitor 1 (SRCIN1) was verified as a potential direct target gene of miR-208a in NSCLC cells. Furthermore, SRCIN1 knockdown was able to rescue the miR-208a-mediated effects on NSCLC cells. In addition to this, silencing miR-208a expression inhibited the extracellular regulated kinase (ERK) signaling pathway in NSCLC. Overall, to the best of our knowledge, the present study is the first to provide evidence that miR-208a exerts oncogenic functions in the carcinogenesis and progression of NSCLC by directly targeting SRCIN1 and regulating the ERK pathway. Therefore, miR-208a may be developed as a potential target for treating patients with NSCLC.

Shikonin derivatives for cancer prevention and therapy

Phytochemicals gained considerable interest during the past years as source to develop new treatment options for chemoprevention and cancer therapy. Motivated by the fact that a majority of established anticancer drugs are derived in one way or another from natural resources, we focused on shikonin, a naphthoquinone with high potentials to be further developed as preventive or therapeutic drug to fight cancer. Shikonin is the major chemical component of Lithospermum erythrorhizon (Purple Cromwell) roots. Traditionally, the root extract has been applied to cure dermatitis, burns, and wounds. Over the past three decades, the anti-inflammatory and anticancer effects of root extracts, isolated shikonin as well as semi-synthetic and synthetic derivatives and nanoformulations have been described. In vitro and in vivo experiments were conducted to understand the effect of shikonin at cellular and molecular levels. Preliminary clinical trials indicate the potential of shikonin for translation into clinical oncology. Shikonin exerts additive and synergistic interactions in combination with established chemotherapeutics, immunotherapeutic approaches, radiotherapy and other treatment modalities, which further underscores the potential of this phytochemical to be integrated into standard treatment regimens.

MicroRNA-133a downregulated EGFR expression in human non-small cell lung cancer cells via AKT/ERK signaling

MicroRNAs (miRNAs) may serve important roles in the regulation of human non-small cell lung cancer (NSCLC) cell growth and apoptosis. To the best of our knowledge, the present study was the first to explore the role of miRNA-133a/epidermal growth factor receptor (EGFR) in regulating NSCLC cell growth and apoptosis via the AKT/extracellular signal-regulated kinase (ERK) signaling pathway. It was determined that miRNA-133a expression was lower in NSCLC tissue than in the adjacent mucosae. Additionally, EGFR expression in the NSCLC tissue was higher compared with in the adjacent mucosae. Furthermore, the upregulation of miRNA-133a in NSCLC cells suppressed cell growth and induced apoptosis. Upregulating miRNA-133a also increased caspase-3 protein expression, while suppressing that of EGFR, phosphorylated (p)-AKT and p-ERK in NSCLC cells. Therefore, the results of the current study demonstrated that miRNA-133a downregulates EGFR expression in NSCLC via the AKT/ERK signaling pathway. These findings provide insights into the function of miRNA-133a in NSCLC, as well as into the molecular mechanisms underlying the miRNA-133a-mediated downregulation of the EGFR/AKT/ERK signaling pathway in NSCLC.

Resveratrol inhibits Erk1/2-mediated adhesion of cancer cells via activating PP2A-PTEN signaling network

Resveratrol, a natural polyphenol compound, has been shown to possess anticancer activity. However, how resveratrol inhibits cancer cell adhesion has not been fully elucidated. Here, we show that resveratrol suppressed the basal or type I insulin-like growth factor (IGF)-1-stimulated adhesion of cancer cells (Rh1, Rh30, HT29, and HeLa cells) by inhibiting the extracellular signal-regulated kinase 1/2 (Erk1/2) pathway. Inhibition of Erk1/2 with U0126, knockdown of Erk1/2, or overexpression of dominant-negative mitogen-activated protein kinase kinase 1 (MKK1) strengthened resveratrol's inhibition of the basal or IGF-1-stimulated of Erk1/2 phosphorylation and cell adhesion, whereas ectopic expression of constitutively active MKK1 attenuated the inhibitory effects of resveratrol. Further research revealed that both protein phosphatase 2A (PP2A) and phosphatase and tensin homolog (PTEN)-Akt were implicated in resveratrol-inactivated Erk1/2-dependent cell adhesion. Inhibition of PP2A with okadaic acid or overexpression of dominant-negative PP2A rendered resistance to resveratrol's suppression of the basal or IGF-1-stimulated phospho-Erk1/2 and cell adhesion, whereas expression of wild-type PP2A enhanced resveratrol's inhibitory effects. Overexpression of wild-type PTEN or dominant-negative Akt or inhibition of Akt with Akt inhibitor X strengthened resveratrol's inhibition of the basal or IGF-1-stimulated Erk1/2 phosphorylation and cell adhesion. Furthermore, inhibition of mechanistic/mammalian target of rapamycin (mTOR) with rapamycin or silencing mTOR enhanced resveratrol's inhibitory effects on the basal and IGF-1-induced inhibition of PP2A-PTEN, activation of Akt-Erk1/2, and cell adhesion. The results indicate that resveratrol inhibits Erk1/2-mediated adhesion of cancer cells via activating PP2A-PTEN signaling network. Our data highlight that resveratrol has a great potential in the prevention of cancer cell adhesion.

Senescence Inducer Shikonin ROS-Dependently Suppressed Lung Cancer Progression

Lung adenocarcinoma (LAC), predominant subclassfication of lung cancer, leads high incidence and mortality annually worldwide. During the premalignant transition from lung adenomas to LAC, cellular senescence is regard as a critical physiological barrier against tumor progression. Nevertheless, the role of senescence in tumorigenesis is controversial and few senescence inducers are extensively determined. In this study, we used two classical cell lines A549 and H1299 and two NSCLC xenograft models on Balb/c-nude mice to reveal the pro-senescence effects of shikonin and the corresponding underlying mechanism in LAC. Shikonin, a pure compound isolated from the herbal medicine Lithospermum erythrorhizon, remarkably stimulated cellular senescence including increased SAHF formation, enlarged cellular morphology, and induced SA-β-Gal positive staining. Further mechanism study revealed that the pro-senescence effect of shikonin was dependent on the increased intercellular ROS generation, which subsequently triggered DNA damage-p53/p21^waf axis without activating oncogenes such as Ras and MEK-1. Meanwhile, Kdm2b, an H3K36me2-specific demethylase effectively suppressed ROS generation, was also notably suppressed by shikonin treatment. Moreover, shikonin at 10 mg/kg significantly inhibited tumor weights by 55.84% and 50.98% in A549 and H1299 xenograft model, respectively (P < 0.05) through activating cellular senescence. Our study suggested that shikonin, a ROS-dependent senescence inducer, could serve as a promising agent for further lung cancer treatment.

RNA-seq transcriptome analysis of breast cancer cell lines under shikonin treatment

Shikonin is a naphthoquinone isolated from the dried root of Lithospermum erythrorhizon, an herb used in Chinese medicine. Although several studies have indicated that shikonin exhibits antitumor activity in breast cancer, the mechanism of action remains unclear. In the present study, we performed transcriptome analysis using RNA-seq and explored the mechanism of action of shikonin in regulating the growth of different types of breast cancer cells. The IC₅₀ of shikonin on MCF-7, SKBR-3 and MDA-MB-231 cells were 10.3 μΜ, 15.0 μΜ, 15.0 μΜ respectively. Our results also demonstrated that shikonin arrests the progression of cell cycle and induces apoptosis in MDA-MB-231 cells. Using RNA-seq transcriptome analysis, we found 38 common genes that significantly express in different types of breast cancer cells under shikonin treatment. In particular, our results indicated that shikonin induces the expression of dual specificity phosphatase (DUSP)-1 and DUSP2 in both RNA and protein levels. In addition, shikonin also inhibits the phosphorylation of JNK and p38, the downstream signaling molecules of DUSP1 and DUSP2. Therefore, our results suggest that shikonin induces the expression of DUSP1 and DUSP2 which consequently switches off JNK and p38 MAPK pathways and causes cell cycle arrest and apoptosis in breast cancer cells.

Shikonin causes apoptosis by disrupting intracellular calcium homeostasis and mitochondrial function in human hepatoma cells

Shikonin is known to suppress proliferation and induce apoptosis in a variety of cancer cell lines. In the present study, SMMC-7721 human hepatocellular carcinoma cells were treated with shikonin (1, 2 or 4 µM) for 12–48 h. Cell morphological alterations and DNA damage were determined. Furthermore, changes in cell cycle, mitochondrial transmembrane potential, calcium homeostasis and levels of reactive oxygen species were measured. Shikonin-treated SMMC-7721 cells exhibited morphological changes and DNA damage. Shikonin inhibited cell proliferation causing cell cycle arrest at the G₀/G₁ phase and induced apoptosis in a dose- and time-dependent manner. Shikonin-induced apoptosis was associated with activation of caspases-3, −8 and −9, elevated levels of intracellular Ca²⁺ and reactive oxygen species, reduced mitochondrial membrane potential and enhanced efflux of Ca²⁺ and K⁺. Gene expression B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax), p53 and caspase-3 was up-regulated, whereas Bcl-2 expression was downregulated. Shikonin caused apoptosis by inhibiting cell cycle progression, disrupting Ca²⁺ homeostasis, inducing oxidative stress and triggering mitochondrial dysfunction. Activation of caspases-3, −8 and −9, K⁺ efflux, and regulation of Bax, Bcl-2, p53 and caspase-3 expression are involved in the process. These results provide in-depth insight into the mechanisms of action of shikonin in the treatment of cancer.

Dual treatment with shikonin and temozolomide reduces glioblastoma tumor growth, migration and glial-to-mesenchymal transition

PURPOSE

Glioblastomas (GBM) comprise 17% of all primary brain tumors. These tumors are extremely aggressive due to their infiltrative capacity and chemoresistance, with glial-to-mesenchymal transition (GMT) proteins playing a prominent role in tumor invasion. One compound that has recently been used to reduce the expression of these proteins is shikonin (SHK), a naphthoquinone with anti-tumor properties. Temozolomide (TMZ), the most commonly used chemotherapeutic agent in GBM treatment, has so far not been studied in combination with SHK. Here, we investigated the combined effects of these two drugs on the proliferation and motility of GBM-derived cells.

METHODS

The cytotoxic and proliferative effects of SHK and TMZ on human GBM-derived cells were tested using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), Ki67 staining and BrdU incorporation assays. The migration capacities of these cells were evaluated using a scratch wound assay. The expression levels of β3 integrin, metalloproteinases (MMPs) and GMT-associated proteins were determined by Western blotting and immunocytochemistry.

RESULTS

We found that GBM-derived cells treated with a combination of SHK and TMZ showed decreases in their proliferation and migration capacities. These decreases were followed by the suppression of GMT through a reduction of β3 integrin, MMP-2, MMP-9, Slug and vimentin expression via inactivation of PI3K/AKT signaling.

CONCLUSION

From our results we conclude that dual treatment with SHK and TMZ may constitute a powerful new tool for GBM treatment by reducing therapy resistance and tumor recurrence.

APRIL, BCMA and TACI proteins are abnormally expressed in non-small cell lung cancer

Lung cancer is the leading cause of cancer-associated mortality. Non-small cell lung cancer (NSCLC) accounts for >80% of lung cancers. The overall survival for NSCLC is dismal, with a 5-year survival of <5% for patients. Thus, identifying an effective biomarker for early diagnosis of lung cancer is the first essential step to reduce mortality. It has been recognized that certain inflammatory and immune responses are important in lung cancer development and prevention. The present study demonstrated that, in NSCLC, a proliferation-inducing ligand (APRIL), B-cell maturation antigen (BCMA)and transmembrane activator and CAML interactor (TACI) proteins are abnormally expressed by immunohistochemistry, reverse transcription-quantitative polymerase chain reaction and western blotting. In addition, the expression of APRIL, BCMA and TACI were observed to be involved in extracellular signal-regulated kinase (ERK)1/2 activation in A549 cells. Overall, the present study provides evidence that APRIL and its receptors, BCMA and TACI, may play roles in the biological processes of NSCLC tumors through the ERK1/2 signaling pathway.

Molecular association of CD98, CD29, and CD147 critically mediates monocytic U937 cell adhesion

Adhesion events of monocytes represent an important step in inflammatory responses induced by chemokines. The β1-integrin CD29 is a major adhesion molecule regulating leukocyte migration and extravasation. Although several adhesion molecules have been known as regulators of CD29, the molecular interactions between CD29 and its regulatory adhesion molecules (such as CD98 and CD147) have not been fully elucidated. Therefore, in this study, we examined whether these molecules are functionally, biochemically, and cell-biologically associated using monocytic U937 cells treated with aggregation-stimulating and blocking antibodies, as well as enzyme inhibitors. The surface levels of CD29, CD98, and CD147 (but not CD43, CD44, and CD82) were increased. The activation of CD29, CD98, and CD147 by ligation of them with aggregation-activating antibodies triggered the induction of cell-cell adhesion, and sensitivity to various enzyme inhibitors and aggregation-blocking antibodies was similar for CD29-, CD98-, and CD147-induced U937 cell aggregation. Molecular association between these molecules and the actin cytoskeleton was confirmed by confocal microscopy and immunoprecipitation. These results strongly suggest that CD29 might be modulated by its biochemical and cellular regulators, including CD98 and CD147, via the actin cytoskeleton.

Shikonin induces apoptosis of lung cancer cells via activation of FOXO3a/EGR1/SIRT1 signaling antagonized by p300

Shikonin derivatives exert powerful cytotoxic effects including induction of apoptosis. Here, we demonstrate the cytotoxic efficacy of shikonin in vivo in xenograft models, which did not affect body weight as well as its reduction of cell viability in vitro using several non-small cell lung cancer (NSCLC) cell lines. We found that inhibition of AKT by shikonin activated the forkhead box (FOX)O3a/early growth response protein (EGR)1 signaling cascade and enhanced the expression of the target gene Bim, leading to apoptosis in lung cancer cells. Overexpression of wild-type or a constitutively active mutant of FOXO3a enhanced shikonin-induced Bim expression. The NAD⁺-dependent histone deacetylase sirtuin (SIRT)1 amplified the pro-apoptotic effect by deacetylating FOXO3a, which induced EGR1 binding to the Bim promoter and activated Bim expression. Meanwhile, PI3K/AKT activity was enhanced, whereas that of FOXO3a was reduced and p300 was upregulated by treatment with a sublethal dose of shikonin. FOXO3a acetylation was enhanced by p300 overexpression, while shikonin-induced Bim expression was suppressed by p300 overexpression, which promoted cell survival. FOXO3a acetylation was increased by p300 overexpression and treatment with SIRT1 inhibitor, improving cell survival. In addition, shikonin-induced FOXO3a nuclear localization was blocked by AKT activation and SIRT1 inhibition, which blocked Bim expression and conferred resistance to the cytotoxic effects of shikonin. The EGR1 increase induced by shikonin was restored by pretreatment with SIRT1 inhibitor. These results suggest that shikonin induces apoptosis in some lung cancer cells via activation of FOXO3a/EGR1/SIRT1 signaling, and that AKT and p300 negatively regulate this process via Bim upregulation.

Integrins mediate mechanical compression-induced endothelium-dependent vasodilation through endothelial nitric oxide pathway

Integrins mediate endothelial NO production and vasodilation in response to the compression of muscle arterioles.

Cardiac and skeletal muscle contraction lead to compression of intramuscular arterioles, which, in turn, leads to their vasodilation (a process that may enhance blood flow during muscle activity). Although endothelium-derived nitric oxide (NO) has been implicated in compression-induced vasodilation, the mechanism whereby arterial compression elicits NO production is unclear. We cannulated isolated swine (n = 39) myocardial (n = 69) and skeletal muscle (n = 60) arteriole segments and exposed them to cyclic transmural pressure generated by either intraluminal or extraluminal pressure pulses to simulate compression in contracting muscle. We found that the vasodilation elicited by internal or external pressure pulses was equivalent; moreover, vasodilation in response to pressure depended on changes in arteriole diameter. Agonist-induced endothelium-dependent and -independent vasodilation was used to verify endothelial and vascular smooth muscle cell viability. Vasodilation in response to cyclic changes in transmural pressure was smaller than that elicited by pharmacological activation of the NO signaling pathway. It was attenuated by inhibition of NO synthase and by mechanical removal of the endothelium. Stemming from previous observations that endothelial integrin is implicated in vasodilation in response to shear stress, we found that function-blocking integrin α₅β₁ or α_vβ₃ antibodies attenuated cyclic compression–induced vasodilation and NO_x (NO⁻₂ and NO⁻₃) production, as did an RGD peptide that competitively inhibits ligand binding to some integrins. We therefore conclude that integrin plays a role in cyclic compression–induced endothelial NO production and thereby in the vasodilation of small arteries during cyclic transmural pressure loading.

Suppression of A549 cell proliferation and metastasis by calycosin via inhibition of the PKC‑α/ERK1/2 pathway: An in vitro investigation

The migration and invasion of lung cancer cells into the extracellular matrix contributes to the high mortality rates of lung cancer. The protein kinase C (PKC) and downstream signaling pathways are important in the invasion and migration of lung cancer cells. Calycosin (Cal), an effector chemical from Astragalus has been reported to affect the recurrence and metastasis of cancer cells via the regulation of the protein expression of matrix metalloproteinases (MMPs). The inhibition of Cal on the migration and invasion of A549 cells was investigated in the present study. Cell viability and apoptosis assays were performed using MTT and flow cytometric analyses. A wound healing assay and Transwell invasion assay were performed to evaluate the effect of Cal on A549 cell migration and invasion. Invasion-associated proteins, including MMP-2, MMP-9, E-cadherin (E-cad), integrin β1, PKC-α and extracellular signal-regulated kinase 1/2 (ERK1/2) were detected using western blotting. In addition, PKC-α inhibitor, AEB071, and ERK1/2 inhibitor, PD98059, were used to determine the association between the suppression of PKC-α/ERK1/2 and invasion, MMP-2, MMP-9, E-cad and integrin β1. Cal was observed to suppress cell proliferation and induce apoptosis. There were significant differences between the phorbol-12-myristate-13-acetate (TPA)-induced A549 cells treated with Cal and the untreated cells in the rates of migration and invasion. The levels of MMP-2, MMP-9, E-cad and integrin β1 in the TPA-induced A549 cells changed markedly, compared with the untreated cells. In addition, the suppression of Cal was affected by the PKC inhibitor, AEB071, an ERK1/2 inhibitor, PD98059. The results of the present study indicated that Cal inhibited the proliferation, adhesion, migration and invasion of the TPA-induced A549 cells. The Cal-induced repression of PKC-α/ERK1/2, increased the expression of E-Cad and inhibited the expression levels of MMP-2, MMP-9 and integrin β1, which possibly demonstrates the mechanism underlying the biological anticancer effects of Cal.

Effect of shikonin on multidrug resistance in HepG2: The role of SIRT1

CONTEXT

Overexpression of SIRT1 is considered to enhance the resistance of HepG2 cells to irradiation. Shikonin, a naturally occurring naphthoquinone compound, displays anticancer effects and circumvents cancer drug resistance.

OBJECTIVES

This study investigated the MDR reversal effect of shikonin induced by the overexpression of SIRT1.

MATERIALS AND METHODS

The overexpression of SIRT1 in HepG2 cells was established by lentivirus infection. Five days after transduction, real-time quantitative polymerase chain reaction and western blotting were used to detect the expression of SIRT1 and MDR1/P-gp. Drug resistance was also evaluated by flow cytometry after rhodamine-123 staining. On day 5, the multidrug resistance cells were treated by shikonin (10(-7), 10(-6), and 10(-5) µmol/L) one time. The cell viability was detected by the MTT assay, and apoptosis was evaluated by Hoechst 33342 staining and caspase-3 activity 24 h after shikonin treatment.

RESULTS

Overexpression of SIRT1 decreased rhodamine-123 staining and successfully produced the R-HepG2 cell line. Compared with HepG2, the expression of MDR1/P-gp mRNA (3.45 ± 0.35) and protein (1.40 ± 0.05) were both upregulated in R-HepG2. Shikonin inhibited cell viability (from 93.9 ± 2.1 to 66.7 ± 1.5%), induced apoptosis of R-HepG2 (apoptotic ratio from 3.5 ± 0.8 to 47.5 ± 2.7%, caspase-3 activity from 103.5 ± 1.9 to 329.2 ± 14.9%, respectively), downregulated the mRNA and protein expression of SIRT1 and MDR1/P-gp, and decreased rhodamin 123 efflux.

DISCUSSION AND CONCLUSION

In the present study, we demonstrated that shikonin is able to overcome drug resistance in hepatocellular carcinoma cells, and the mechanism is related to the SIRT1-MDR1/P-gp signaling pathway.

Differential proteomic analysis on the effects of 2-methoxy-1,4-naphthoquinone towards MDA-MB-231 cell line

BACKGROUND

We have previously reported the anti-metastatic effects of 2-methoxy-1,4-naphthoquinone (MNQ) against MDA-MB-231 cell line.

PURPOSE

To investigate the molecular mechanism underlying the anti-metastatic effects of MNQ towards MDA-MB-231 cell line via the comparative proteomic approach.

STUDY DESIGN/METHODS

Differentially expressed proteins in MNQ-treated MDA-MB-231 cells were identified by using two-dimensional gel electrophoresis coupled with tandem mass spectrometry. Proteins and signalling pathways associated with the identified MNQ-altered proteins were studied by using Western blotting.

RESULTS

Significant modulation of MDA-MB-231 cell proteome was observed upon treatment with MNQ in which the expressions of 19 proteins were found to be downregulated whereas another eight were upregulated (>1.5 fold, p < 0.05). The altered proteins were mainly related to cytoskeletal functions and regulations, mRNA processing, protein modifications and oxidative stress response. Notably, two of the downregulated proteins, protein S100-A4 (S100A4) and laminin-binding protein (RPSA) are known to play key roles in driving metastasis and were verified using Western blotting. Further investigation using Western blotting also revealed that MNQ decreased the activations of pro-metastatic ERK1/2 and NF-κB signalling pathways. Moreover, MNQ was shown to stimulate the expression of the metastatic suppressor, E-cadherin.

CONCLUSION

This study reports a proposed mechanism by which MNQ exerts its anti-metastatic effects against MDA-MB-231 cell line. The findings from this study offer new insights on the potential of MNQ to be developed as a novel anti-metastatic agent.

Shikonin inhibits the cell viability, adhesion, invasion and migration of the human gastric cancer cell line MGC-803 via the Toll-like receptor 2/nuclear factor-kappa B pathway

OBJECTIVES

Shikonin is an active naphthoquinone pigment isolated from the root of Lithospermum erythrorhizon. This study was designed to explore the inhibition of Shikonin on cell viability, adhesion, migration and invasion ability of gastric cancer (GC) and its possible mechanism.

METHODS

3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was performed for cell viability and adhesion ability of MGC-803 cells. Cell scratch repair experiments were conducted for the determination of migration ability while transwell assay for cell invasion ability. Western blot analysis and real-time polymerase chain reaction assay were used for the detection of protein and mRNA expressions.

KEY FINDINGS

Fifty per cent inhibitory concentration of Shikonin on MGC-803 cells was 1.854 μm. Shikonin (1 μm) inhibited significantly the adhesion, invasion and migratory ability of MGC-803 cells. Interestingly, Shikonin in the presence or absence of anti-Toll-like receptor 2 (TLR2) antibody (2 μg) and nuclear factor-kappa B (NF-κB) inhibitor MG-132 (10 μm) could decrease these ability of MGC-803 cells markedly, as well as the expression levels of matrix metalloproteinases (MMP)-2, MMP-7, TLR2 and p65 NF-κB. In addition, the co-incubation of Shikonin and anti-TLR2/MG-132 has a significant stronger activity than anti-TLR2 or MG-132 alone.

CONCLUSIONS

The results indicated that Shikonin could suppress the cell viability, adhesion, invasion and migratory ability of MGC-803 cells through TLR2- or NF-κB-mediated pathway. Our findings provide novel information for the treatment of Shikonin on GC.

Biologically active metabolites produced by the basidiomycete Quambalaria cyanescens

Four strains of the fungus Quambalaria cyanescens (Basidiomycota: Microstromatales), were used for the determination of secondary metabolites production and their antimicrobial and biological activities. A new naphthoquinone named quambalarine A, (S)-(+)-3-(5-ethyl-tetrahydrofuran-2-yliden)-5,7,8-trihydroxy-2-oxo-1,4-naphthoquinone (1), together with two known naphthoquinones, 3-hexanoyl-2,5,7,8-tetrahydroxy-1,4-naphthoquinone (named here as quambalarine B, 2) and mompain, 2,5,7,8-tetrahydroxy-1,4-naphthoquinone (3) were isolated. Their structures were determined by single-crystal X-ray diffraction crystallography, NMR and MS spectrometry. Quambalarine A (1) had a broad antifungal and antibacterial activity and is able inhibit growth of human pathogenic fungus Aspergillus fumigatus and fungi co-occurring with Q. cyanescens in bark beetle galleries including insect pathogenic species Beauveria bassiana. Quambalarine B (2) was active against several fungi and mompain mainly against bacteria. The biological activity against human-derived cell lines was selective towards mitochondria (2 and 3); after long-term incubation with 2, mitochondria were undetectable using a mitochondrial probe. A similar effect on mitochondria was observed also for environmental competitors of Q. cyanescens from the genus Geosmithia.

Shikonin Induces Apoptosis, Necrosis, and Premature Senescence of Human A549 Lung Cancer Cells through Upregulation of p53 Expression

Shikonin, a natural naphthoquinone pigment isolated from Lithospermum erythrorhizon, has been reported to suppress growth of various cancer cells. This study was aimed to investigate whether this chemical could also inhibit cell growth of lung cancer cells and, if so, works via what molecular mechanism. To fulfill this, A549 lung cancer cells were treated with shikonin and then subjected to microscopic, biochemical, flow cytometric, and molecular analyses. Compared with the controls, shikonin significantly induced cell apoptosis and reduced proliferation in a dose-dependent manner. Specially, lower concentrations of shikonin (1-2.5 μg/mL) cause viability reduction; apoptosis and cellular senescence induction is associated with upregulated expressions of cell cycle- and apoptotic signaling-regulatory proteins, while higher concentrations (5-10 μg/mL) precipitate both apoptosis and necrosis. Treatment of cells with pifithrin-α, a specific inhibitor of p53, suppressed shikonin-induced apoptosis and premature senescence, suggesting the role of p53 in mediating the actions of shikonin on regulation of lung cancer cell proliferation. These results indicate the potential and dose-related cytotoxic actions of shikonin on A549 lung cancer cells via p53-mediated cell fate pathways and raise shikonin a promising adjuvant chemotherapeutic agent for treatment of lung cancer in clinical practice.

Design, synthesis and mechanism of novel shikonin derivatives as potent anticancer agents

Novel shikonin derivatives were synthesised and probed as anticancer agents. Compound 40 showed the best anticancer activity with an IC₅₀ of 1.26 μM, could induce apoptosis and cause cell cycle arrest at the G2/M phase via the P21 p-CDC2 (Tyr15) pathway independent of P53.

Three advantages of using traditional Chinese medicine to prevent and treat tumor

Traditional Chinese medicine (TCM), an important component of complementary and alternative medicine, has evolved over thousands of years with its own unique system of theories, diagnostics and therapies. TCM has been increasingly used in the last decades and become well known for its significant role in preventing and treating cancer. We believe that TCM possesses advantages over Western medicine in specific aspects at a certain stage of cancer treatment. Here we summarize the advantages of TCM from three aspects: preventing tumorigenesis; attenuating toxicity and enhancing the treatment effect; and reducing tumor recurrence and metastasis.

CCR7 regulates cell migration and invasion through MAPKs in metastatic squamous cell carcinoma of head and neck

Migration and invasion of tumor cells are essential prerequisites for the formation of metastasis in malignant diseases. Previously, we have reported that CC chemokine receptor 7 (CCR7) regulates the mobility of squamous cell carcinoma of head and neck (SCCHN) cells through several pathways, such as integrin and cdc42. In this study, we investigated the connection between CCR7 and mitogen-activated protein kinase (MAPK) family members, and their influence on cell invasion and migration in metastatic SCCHN cells. Western blotting, immunostaining and fluorescence microcopy were used to detect the protein expression and distribution of MAPKs, and the Migration assay, Matrigel invasion assay and wound-healing assay to detect the role of MAPKs in CCR7 regulating cell mobility. To analyze the correlation between CCR7 and MAPK activity and clinicopathological factors immunohistochemical staining was emplyed. The results showed stimulation of CCL19 and the activation of CCR7 could induce ERK1/2 and JNK phosphorylation, while it had no efect on p38. After activation, ERK1/2 and JNK promoted E-cadherin low expression and Vimentin high expression. The MAPK pathway not only mediated CCR7 induced cell migration, but also mediated invasion speed. The immunohistochemistry results showed that CCR7 was correlated with the phosphorylation of ERK1/2 and JNK in SCCHN, and these molecules were all associated with lymph node metastasis. Therefore, our study demonstrates that MAPK members (ERK1/2 and JNK) play a key role in CCR7 regulating SCCHN metastasis.