Shikonin blocks migration and invasion of human breast cancer cells through inhibition of matrix metalloproteinase-9 activation

Review on Natural Agents as Aromatase Inhibitors: Management of Breast Cancer

Breast cancer is a prevalent type of cancer that is typically hormone-dependent, caused by estrogen. Aromatase inhibitors are frequently utilised in the treatment of hormonereceptor- positive breast cancer because they prevent the enzyme aromatase from converting androgens to estrogens. Natural medicines with aromatase inhibitory characteristics have attracted interest as potential alternatives or complementary therapy to manufactured medications. This review discusses the function of natural agents as aromatase inhibitors in treating breast cancer. A variety of natural compounds have been investigated for their capacity to inhibit aromatase activity and lower estrogen levels. These agents include resveratrol from red wine and grapes, curcumin from turmeric extract and green teahigh in catechins, and other flavonoids such as genistein, luteolin and quercetin. It has been demonstrated that by decreasing estrogen synthesis, they can slow the growth of breast cancer cells that are dependent on estrogen. However, the clinical evidence supporting their efficacy and safety in breast cancer treatment is inadequate. More research is required to investigate the therapeutic potential of natural medicines, such as aromatase inhibitors, in treating breast cancer. The clinical trials are required to assess their efficacy, appropriate doses, and potential interactions with other therapies. In conclusion, natural aromatase inhibitory drugs are promising adjuncts in the treatment of hormone receptor-positive breast cancer. Their clinical value and safety profile, however, require additional investigation.

OncomiRs as noncoding RNAs having functions in cancer: Their role in immune suppression and clinical implications

Currently, microRNAs have been established as central players in tumorigenesis, but above all, they have opened an important door for our understanding of immune and tumor cell communication. This dialog is largely due to onco-miR transfer from tumor cells to cells of the tumor microenvironment by exosome. This review outlines recent advances regarding the role of oncomiRs in enhancing cancer and how they modulate the cancer-related immune response in the tumor immune microenvironment.

MicroRNAs (miRNAs) are a type of noncoding RNA that are important posttranscriptional regulators of messenger RNA (mRNA) translation into proteins. By regulating gene expression, miRNAs enhance or inhibit cancer development and participate in several cancer biological processes, including proliferation, invasion metastasis, angiogenesis, chemoresistance and immune escape. Consistent with their widespread effects, miRNAs have been categorized as oncogenes (oncomiRs) or tumor suppressor (TS) miRNAs. MiRNAs that promote tumor growth, called oncomiRs, inhibit messenger RNAs of TS genes and are therefore overexpressed in cancer. In contrast, TS miRNAs inhibit oncogene messenger RNAs and are therefore underexpressed in cancer. Endogenous miRNAs regulate different cellular pathways in all cell types. Therefore, they are not only key modulators in cancer cells but also in the cells constituting their microenvironments. Recently, it was shown that miRNAs are also involved in intercellular communication. Indeed, miRNAs can be transferred from one cell type to another where they regulate targeted gene expression. The primary carriers for the transfer of miRNAs from one cell to another are exosomes. Exosomes are currently considered the primary carriers for communication between the tumor and its surrounding stromal cells to support cancer progression and drive immune suppression. Exosome and miRNAs are seen by many as a hope for developing a new class of targeted therapy. This review outlines recent advances in understanding the role of oncomiRs in enhancing cancer and how they promote its aggressive characteristics and deeply discusses the role of oncomiRs in suppressing the anticancer immune response in its microenvironment. Additionally, further understanding the mechanism of oncomiR-related immune suppression will facilitate the use of miRNAs as biomarkers for impaired antitumor immune function, making them ideal immunotherapy targets.

Herbal Ingredients in the Prevention of Breast Cancer: Comprehensive Review of Potential Molecular Targets and Role of Natural Products

Among various cancers, breast cancer is the most prevalent type in women throughout the world. Breast cancer treatment is challenging due to complex nature of the etiology of disease. Cell division cycle alterations are often encountered in a variety of cancer types including breast cancer. Common treatments include chemotherapy, surgery, radiotherapy, and hormonal therapy; however, adverse effects and multidrug resistance lead to complications and noncompliance. Accordingly, there is an increasing demand for natural products from medicinal plants and foods. This review summarizes molecular mechanisms of signaling pathways in breast cancer and identifies mechanisms by which natural compounds may exert their efficacy in the treatment of breast cancer.

Natural Small Molecules in Breast Cancer Treatment: Understandings from a Therapeutic Viewpoint

Breast cancer (BrCa) is the most common malignancy in women and the second most significant cause of death from cancer. BrCa is one of the most challenging malignancies to treat, and it accounts for a large percentage of cancer-related deaths. The number of cases requiring more effective BrCa therapy has increased dramatically. Scientists are looking for more productive agents, such as organic combinations, for BrCa prevention and treatment because most chemotherapeutic agents are linked to cancer metastasis, the resistance of the drugs, and side effects. Natural compounds produced by living organisms promote apoptosis and inhibit metastasis, slowing the spread of cancer. As a result, these compounds may delay the spread of BrCa, enhancing survival rates and reducing the number of deaths caused by BrCa. Several natural compounds inhibit BrCa production while lowering cancer cell proliferation and triggering cell death. Natural compounds, in addition to therapeutic approaches, are efficient and potential agents for treating BrCa. This review highlights the natural compounds demonstrated in various studies to have anticancer properties in BrCa cells. Future research into biological anti-BrCa agents may pave the way for a new era in BrCa treatment, with natural anti-BrCa drugs playing a key role in improving BrCa patient survival rates.

Formulation Strategies and Therapeutic Applications of Shikonin and Related Derivatives

Shikonin and its derivatives are excellent representatives of biologically active naphthoquinones. A wide range of investigations carried out in the last few decades validated their pharmacological efficacy. Besides having magnificent therapeutic potential, shikonin and its derivatives suffer from various pharmacokinetic, toxicity, and stability issues like poor bioavailability, nephrotoxicity, photodegradation, etc. Recently, various research groups have developed an extensive range of formulations to tackle these issues to ease their path to clinical practice. The latest formulation approaches have been focused on exploiting the unique features of novel functional excipients, which in turn escalate the therapeutic effect of shikonin. Moreover, the codelivery approach in various drug delivery systems has been taken into consideration in a recent while to reduce toxicity associated with shikonin and its derivatives. This review sheds light on the essential reports and patents published related to the array of formulations containing shikonin and its derivatives.

In vitro antitumor activity of dialkylamine-1,4-naphthoquinones toward human glioblastoma multiforme cells

In this study, we evaluated the in vitro antitumor activity of dialkylamino-1,4-naphthoquinones (1a–n) toward human glioblastoma multiforme cells (GBM02).

Shikonin Alleviates Endothelial Cell Injury Induced by ox-LDL via AMPK/Nrf2/HO-1 Signaling Pathway

The present study aimed to explore the effects of shikonin (SKN) on the damage of human venous endothelial cells (HUVECs) induced by ox-LDL and the underlying molecular mechanism. The HUVECs were randomly divided into six groups: control, ox-LDL, SKN + ox-LDL, SKN + ox-LDL + compound C, SKN + ox-LDL + si-Nrf2, and SKN + ox-LDL + si-HO-1. The MTT method was used to detect cell viability, flow cytometry was used to detect cell apoptosis and reactive oxygen species (ROS) levels, and Western blot was used to detect protein levels. Compared to the control group, the cell viability of the ox-LDL group decreased, the apoptosis rate increased, the level of cleaved caspase-3 was upregulated, and the level of Bcl-2 protein was downregulated. The level of TNF-α, IL-1β, IL-6, vascular cell adhesion molecule-1 (VCAM1), intercellular adhesion molecule-1 (ICAM1), and E-selectin (E-sel) was increased, ROS levels increased, and superoxide dismutase (SOD) level decreased. Moreover, the protein levels of p-AMPK, Nrf2, and HO-1 were decreased. Compared to the ox-LDL group, SKN treatment improves cell viability, alleviates cell apoptosis and oxidative stress injury, and upregulates the protein levels of p-AMPK, Nrf2, and HO-1. Compound C, si-Nrf2, and si-HO-1 administration inhibits the AMPK/Nrf2/HO-1 signaling pathway, increases ROS generation, and inhibits the antagonistic effect of SKN on ox-LDL-induced HUVECs damage. In summary, SKN suppressed ox-LDL-induced ROS production and improved cell viability and cell apoptosis via the AMPK/Nrf2/HO-1 pathway.

Alkannin Inhibits the Development of Ovarian Cancer by Affecting miR-4461

Background

Previous studies have shown that alkannin has anticancer, anti-inflammatory, and antibacterial effects. However, the effect of alkannin in the development of ovarian cancer (OC) remains unknown. Therefore, this study aims to elucidate the function of alkannin in OC progression.

Methods

RT-qPCR and western blot analysis were used to measure mRNA and protein expression. Cell viability and metastasis were detected by the CCK-8 assay, flow cytometry analysis, and transwell assay.

Results

Alkannin had no cytotoxicity toward normal ovarian cells, but alkannin can inhibit cell proliferation and induce apoptosis in OC cells. In addition, alkannin inhibited cell migration and invasion and blocked EMT in OC. Besides, upregulation of miR-4461 was found in OC tissues and cells, which was regulated by alkannin. More importantly, miR-4461 can inverse the effects of alkannin on cell viability and metastasis in OC cells.

Conclusion

Alkannin restrains cell viability, metastasis, and EMT in OC by downregulating miR-4461 expression.

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 Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

ACNPD: The Database for Elucidating the Relationships Between Natural Products, Compounds, Molecular Mechanisms, and Cancer Types

Objectives: Cancer is well-known as a collection of diseases of uncontrolled proliferation of cells caused by mutated genes which are generated by external or internal factors. As the mechanisms of cancer have been constantly revealed, including cell cycle, proliferation, apoptosis and so on, a series of new emerging anti-cancer drugs acting on each stage have also been developed. It is worth noting that natural products are one of the important sources for the development of anti-cancer drugs. To the best of our knowledge, there is not any database summarizing the relationships between natural products, compounds, molecular mechanisms, and cancer types.

Materials and methods: Based upon published literatures and other sources, we have constructed an anti-cancer natural product database (ACNPD) (http://www.acnpd-fu.com/). The database currently contains 521 compounds, which specifically refer to natural compounds derived from traditional Chinese medicine plants (derivatives are not considered herein). And, it includes 1,593 molecular mechanisms/signaling pathways, covering 10 common cancer types, such as breast cancer, lung cancer and cervical cancer.

Results: Integrating existing data sources, we have obtained a large amount of information on natural anti-cancer products, including herbal sources, regulatory targets and signaling pathways. ACNPD is a valuable online resource that illustrates the complex pharmacological relationship between natural products and human cancers.

Conclusion: In summary, ACNPD is crucial for better understanding of the relationships between traditional Chinese medicine (TCM) and cancer, which is not only conducive to expand the influence of TCM, but help to find more new anti-cancer drugs in the future.

Semi-Synthesis and In Vitro Anti-Cancer Evaluation of Magnolol Derivatives

Magnolol (MAG), a biphenolic neolignan, has various biological activities including antitumor effects. In this study, 15 MAG derivatives were semi-synthesized and evaluated for their in vitro anticancer activities. From these derivatives, compound 6a exhibited the best cytotoxic activity against four human cancer cell lines, with IC₅₀ values ranging from 20.43 to 28.27 μM. Wound-healing and transwell assays showed that compound 6a significantly inhibited the migration and invasion of MDA-MB-231 cells. In addition, Western blotting experiments, performed using various concentrations of 6a, demonstrated that it downregulates the expression of HIF-1α, MMP-2, and MMP-9 in a concentration-dependent manner. Overall, these results suggest that substituting a benzyl group having F atoms substituted at the C2 position on MAG is a viable strategy for the structural optimization of MAG derivatives as anticancer agents.

Natural Products as a Promising Therapeutic Strategy to Target Cancer Stem Cells

Cancer is still a deadly disease, and its treatment desperately needs to be managed in a very sophisticated way through fast-developing novel strategies. Most of the cancer cases eventually develop into recurrencies, for which cancer stem cells (CSCs) are thought to be responsible. They are considered as a subpopulation of all cancer cells of tumor tissue with aberrant regulation of self-renewal, unbalanced proliferation, and cell death properties. Moreover, CSCs show a serious degree of resistance to chemotherapy or radiotherapy and immune surveillance as well. Therefore, new classes of drugs are rushing into the market each year, which makes the cost of therapy increase dramatically. Natural products are also becoming a new research area as a diverse chemical library to suppress CSCs. Some of the products even show promise in this regard. So, the near future could witness the introduction of natural products as a source of new chemotherapy modalities, which may result in the development of novel anticancer drugs. They could also be a reasonably-priced alternative to highly expensive current treatments. Nowadays, considering the effects of natural compounds on targeting surface markers, signaling pathways, apoptosis, and escape from immunosurveillance have been a highly intriguing area in preclinical and clinical research. In this review, we present scientific advances regarding their potential use in the inhibition of CSCs and the mechanisms by which they kill the CSCs.

Shikonin promotes ubiquitination and degradation of cIAP1/2-mediated apoptosis and necrosis in triple negative breast cancer cells

Background

Shikonin (SKO) is a natural naphthoquinone derived from Chinese herbal medicine Arnebiae Radix with high development potentials due to its anti-inflammatory and anti-tumor activities. Overwhelming evidences have indicated that SKO can induce both necrosis and apoptosis in cancer cells, while the mechanisms for triple negative breast cancer cells is still need to be disclosed.

Methods

In this study, kinds of molecular biological technologies, including flow-cytometry, Western blot, immunoprecipitation, enzyme-linked immunosorbent assay (ELISA) as well as real-time quantitative PCR (RT-qPCR), were applied for investigation on the underlying mechanisms of SKO induced necrosis and apoptosis for MDA-MB-231 cells. Inhibitors were also used for validation ofthe key signaling pathways involved in SKO triggered necrosis and apoptosis.

Results

We found that SKO significantly triggered necrosis and apoptosis of MDA-MB-231 cells in both a concentration- and time-dependent manner. Mechanism studies demonstrated that SKO significantly promoted the autoubiquitination levels and facilitated the proteasome dependent degradation of cellular inhibitor of apoptosis protein 1 (cIAP1) and cIAP2 in MDA-MB-231 cells. Autoubiquitination and degradation of cIAP1 and cIAP2 induced by SKO further led to significant decreased ubiquitination and inactivation of RIP1, which played an important role in inhibition of pro-survival and accelerating of necrosis of MDA-MB-231 cells. Treatment with proteasome inhibitor lactacystin significantly rescued the cell viability induced by treatment of SKO.

Conclusions

Our results demonstrate that SKO promotes the autoubiquitination and degradation of cIAP1 and cIAP2, which further induces the decrease of the ubiquitination of RIP1 to inhibit the activation of pro-survival signaling pathways and accelerate the necrosis of MDA-MB-231 cells. The disclosed mechanisms of SKO induced necrosis and apoptosis in our study is firstly reported, and it is believed that SKO could be considered as a potential candidate and further developed for the treatment of triple negative breast cancer.

Shikonin Inhibits Cholangiocarcinoma Cell Line QBC939 by Regulating Apoptosis, Proliferation, and Invasion

This study was designed to clarify whether Shikonin causes proliferation, apoptosis, and invasion in cholangiocarcinoma cells and to investigate the mechanism of action. QBC939 cells were cultured with different doses of Shikonin, and then 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium assay was used to detect cell viability. Apoptosis of cells was detected using flow cytometry with Annexin V/propidium iodide (PI) assay after being stained with Hoechst 33242. The role of Shikonin on the invasive and metastasis ability was detected using Transwell invasion assay. Real-time polymerase chain reaction and Western blotting were used to detect the expression of caspase-3, caspase-8, epidermal growth factor receptor (EGFR), and matrix metalloproteinase (MMP)-9. Shikonin inhibited proliferation and invasive ability of QBC939 cells in a dose-dependent manner; at the same time, apoptosis of cells was also observed in a concentration-dependent fashion. Moreover, Annexin V/PI assay and Transwell invasion assay results indicated that Shikonin induced apoptosis and invasion inhibitory probably due to upregulation of caspase-3 and caspase-8 expression and downregulation of MMP-9 and EGFR expression in a concentration-dependent fashion. Shikonin could enhance apoptosis and inhibit proliferation and invasion of QBC939 cells; such biological behaviors mainly occurred via upregulating the expression of caspase-3 and caspase-8 and downregulating the expression of MMP-9 and EGFR.

Shikonin inhibits migration and invasion of triple-negative breast cancer cells by suppressing epithelial-mesenchymal transition via miR-17-5p/PTEN/Akt pathway

Background: Triple-negative breast cancer (TNBC) is a great threat to global women's health due to its high metastatic potential. Epithelial-to-mesenchymal transition (EMT) is considered as a key event in the process of metastasis. So the pharmacological targeting of EMT might be a promising strategy in improving the therapeutic efficacy of TNBC. Here, we investigated the effect of shikonin exerting on EMT and consequently the metastasis of TNBC cells and its underlying mechanism. Methods: The invasive and migratory capacities of MDA-MB-231 and BT549 cells were tested using transwell invasion and wound healing assay. MiR-17-5p expression was examined by qRT-PCR. MiR-17-5p targeted genes were predicted with different bioinformatic algorithms from four databases (TargetScan, miRanda, PITA and picTar) and further screened by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. The differential expressions of predicted genes and their correlations with miR-17-5p were identified in breast cancer patients based on The Cancer Genome Atlas (TCGA) database. The interaction between phosphatase and tensin homolog deleted on chromosome ten (PTEN) and miR-17-5p was analyzed by luciferase reporter assay. The overexpression vector and small interfering RNA were constructed to investigate the role PTEN played in metastasis and EMT regulation. The expressions of EMT markers, protein kinase B (Akt) and phospho-Akt (p-Akt) were evaluated by western blot. Results: Shikonin suppressed the migration and invasion of MDA-MB-231 and BT549 cells and meanwhile the corresponding alterations of EMT biomarkers were observed in shikonin treated MDA-MB-231 cells. Shikonin inhibited the expression of miR-17-5p, which was upregulated in breast cancer. The 3'-untranslated region (3'-UTR) of PTEN was found to be direct binding target of miR-17-5p by luciferase reporter assays. PTEN functioned as a suppressor both in the metastasis and EMT of TNBC cells. Moreover, Akt and p-Akt (Ser473) were involved in the process of inhibition in cancer cell migration, invasion and EMT by shikonin. Conclusions: Shikonin inhibits migration and invasion of TNBC cells by suppressing EMT via miR-17-5p/PTEN/Akt pathway. This suggests shikonin as a promising therapeutic agent to counteract metastasis in the TNBC patients.

Shikonin relieves osteoporosis of ovariectomized mice by inhibiting RANKL-induced NF-κB and NFAT pathways

Postmenopausal osteoporosis is very common in women. Currently, many kinds of new drugs are being developed for this disease. Postmenopausal osteoporosis is closely related to overactivity of osteoclasts in body. Shikonin is purple red naphthoquinone pigment extracted from lithospermum, which has anti-inflammation, antivirus, anticancer and other bioactivities. At the same time, it has been proved that shikonin can promote the proliferation and differentiation of osteoblasts, but its influence on osteoclasts and molecular mechanism are unknown. Our study showed that shikonin could inhibit the activity and formation of RANKL-mediated osteoclasts depending on dose without affecting the activity of bone marrow macrophages (BMM). In addition, we have also found that shikonin can inhibit the expression of specific marker gene of osteoclasts, including nuclear factor of activated T cells cytoplasmic 1 (NFATc1), cathepsin K (Ctsk), tartrate resistant acid phosphatase (TRAcP) and calcitonin receptor. Shikonin also could promote the proliferation of MC3T3-E1, increasing the expression of mRNA related to osteogenesis, like the expression of bone morphogenetic protein-2 (BMP-2), alkaline phosphatase (ALP), runt-related transcription factor 2 (Runx2) and osteocalcin (OCN). Luciferase reporter gene assay and Western blot analysis further indicated that shikonin could inhibit the activity of RANKL-induced NF-κB and NFAT receptors. Moreover, shikonin can also slow down bone loss of ovariectomized (OVX) mice by inhibiting the activity of osteoclasts. This work explains the molecular mechanism of shikonin in RANKL-mediated formation of osteoclasts, and reveals the potential of further developing shikonin into a new drug for prevention and treatment of postmenopausal osteoporosis.

Alkannin represses growth of pancreatic cancer cells based on the down regulation of miR-199a

Alkannin displays tumor suppressive activity by initiating apoptosis. Here, we corroborated its role in pancreatic carcinoma (PANC-1) cells and addressed the molecular mechanism in which microRNA-199a (miR-199a) and Klotho might be implicated. PANC-1 and MIN6 cells were treated by alkannin and its role was evaluated in cellular viability. Next we assessed the ability of PANC-1 cells to proliferate, migrate, and invade as well as apoptosis process. Besides, proliferating cell nuclear antigen (PCNA), CyclinD1, p53, and caspases were quantified using Western blot. miR-199a was detected by qRT-PCR. miR-199a-silenced or -replenished cells were established to study its function role in Klotho in conjunction with alkannin. Further, Klotho-overexpressed or -silenced cells were constructed to investigate the alteration of mTOR and MEK/ERK pathways. Alkannin repressed the viability of PANC-1 cells instead of MIN6 cells. Alkannin counteracted the growth of PANC-1 cells through inhibiting proliferation, migration, and invasion and facilitating apoptosis, which was evidenced by the modulation on PCNA, CyclinD1, p53, and cleavage of caspases. The silence of miR-199a by alkannin was also involved in the antitumor process. Alkannin enhanced Klotho expression possibly through silencing miR-199a. Besides, mTOR and MEK/ERK signaling were counteracted by Klotho overexpression while facilitated by its silence. Alkannin inhibited the growth of PANC-1 cells via modulating miR-199a-Klotho node. During this process, mTOR and MEK/ERK pathways were blunted.

Shikonin inhibits CEBPD downregulation in IL‑17‑treated HaCaT cells and in an imiquimod‑induced psoriasis model

Psoriasis is a chronic inflammatory skin disease characterized by well-defined scaly papules and plaques. Interleukin (IL)-17 is involved in its pathogenesis and promotes the proliferation of epidermal keratinocytes through signal transducer and activator of transcription 3 (STAT3) activation. Shikonin, a natural naphthoquinone isolated from Lithospermum erythrorhizon, possesses anti-inflammatory and immunosuppressive properties and can suppress IL-17-induced vascular endothelial growth factor expression by inhibiting the JAK/STAT3 pathway. In the present study, MTS, iCELLigence and RT-qPCR were used to determine the optimal concentration and duration of IL-17 or shikonin acting on HaCaT cells. The changes in the expression levels of genes associated with the IL-6/STAT3 pathway in differentially treated cells were analyzed via RT²Profiler™ PCR Array. Small interfering RNA was used to silence the expression levels of the target gene CCAAT/enhancer-binding protein δ (CEBPD). Western blotting and immunohistochemistry were used to evaluate the effect of shikonin on imiquimod-induced psoriasis in mice and the expression levels of CEBPD. Shikonin reversed IL-17-mediated downregulation of the tumor suppressor CEBPD in HaCaT cells. Moreover, low levels of CEBPD in the imiquimod-induced mouse model of psoriasis were restored by shikonin treatment, which ameliorated excessive keratinocyte proliferation. Taken together, these findings suggest that CEBPD plays a key role in the pathogenesis of psoriasis and can be targeted by shikonin as a potential therapeutic strategy.

Inhibition of the STAT3 Signaling Pathway Contributes to the Anti-Melanoma Activities of Shikonin

Background

Malignant melanoma is an extremely aggressive and metastatic cancer, and highly resistant to conventional therapies. Signal transducer and activator of transcription 3 (STAT3) signaling promotes melanoma development and progression, which has been validated as an effective target in melanoma treatment. Natural naphthoquinone shikonin is reported to exert anti-melanoma effects. However, the underlying mechanisms have not been fully elucidated.

Purpose

This study aims to evaluate the anti-melanoma activities of shikonin and explore the involvement of STAT3 signaling in these effects.

Methods

Zebrafish tumor model was established to evaluate the anti-human melanoma effects of shikonin in vivo. MTT assay and colony formation assay were employed to investigate the anti-proliferative effects of shikonin on human melanoma A375 and A2058 cells. Flow cytometry was used to analyze cell cycle distribution and apoptosis induction. Wound healing assay and Transwell chamber assay were conducted to examine the cell migratory and invasive abilities. Immunofluorescence assay was used to observe F-actin, Tubulin, and STAT3 localization. Western blotting was used to determine the expression levels of proteins associated with apoptosis and key proteins in the STAT3 signaling pathway. Immunoblotting was performed in DSS cross-linked cells to determine the homo-dimerization of STAT3. Gelatin zymography was employed to evaluate the enzymatic activity of MMP-2 and MMP-9. Transient transfection was used to overexpress STAT3 in cell models.

Results

Shikonin suppressed melanoma growth in cultured cells and in zebrafish xenograft models. Shikonin induced melanoma cells apoptosis, inhibited cell migration and invasion. Mechanistic study indicated that shikonin inhibited the phosphorylation and homo-dimerization of STAT3, thus reduced its nuclear localization. Further study showed that shikonin decreased the levels of STAT3-targeted genes Mcl-1, Bcl-2, MMP-2, vimentin, and Twist, which are involved in melanoma survival, migration, and invasion. More importantly, overexpression of constitutively active STAT3 partially abolished the anti-proliferative, anti-migratory, and anti-invasive effects of shikonin.

Conclusion

The anti-melanoma activity of shikonin is at least partially attributed to the inhibition on STAT3 signaling. These findings provide new insights into the anti-melanoma molecular mechanisms of shikonin, suggesting its potential in melanoma treatment.

Shikonin and 4-hydroxytamoxifen synergistically inhibit the proliferation of breast cancer cells through activating apoptosis signaling pathway in vitro and in vivo

Background

Tamoxifen (TAM) is a cell type-specific anti-estrogen and is applied to improve the survival of patients with estrogen receptor positive (ER +) breast cancer. However, long-term TAM use can induce serious drug resistance, leading to breast cancer recurrence and death in patients. Further, it is almost useless among patients with estrogen receptor negative (ER −) breast cancer. Shikonin (SK) is a natural product broadly explored in cancer therapy. Some studies have demonstrated the combined treatment of SK and clinical anticancer drugs including TAM on various tumors. However, the combined effect of SK and 4-hydroxytamoxifen (4-OHT) on ER- breast cancer is not known. The current study aimed to assess the combination effects of SK and 4-OHT on human breast cancer cells, MCF-7 (ER +) and MDA-MB-435S (ER −), in vitro and in vivo and to investigate the underlying mechanisms.

Methods

CCK-8 assays and flow cytometry were conducted to determine the cell viability and apoptotic profiles of human breast cancer cell lines (MCF-7 and MDA-MB-435S) treated with SK, 4-OHT, and the combination. ROS and JC-1 assays were used to determine ROS level and mitochondrial membrane potential. Western blot analysis was performed to investigate proteins that are associated with apoptosis. Haematoxylin & Eosin (HE) staining was used to detect the tumor and kidney morphology of mice. TUNEL and immunohistochemical staining were performed to detect Ki67 expression level and cell apoptotic profile in tumor tissues.

Results

SK and 4-OHT synergistically inhibited MCF-7 and MDA-MB-435S cell proliferation and promoted apoptosis by reducing mitochondrial membrane potential and increasing the intracellular ROS level. The combination of SK and 4-OHT activated the mitochondrial-dependent apoptosis and the death receptor pathways, significantly regulating the PI3K/AKT/Caspase 9 signaling pathway. Compared with SK and 4-OHT alone, the combination of SK and 4-OHT could better inhibit tumor growth in mice.

Conclusion

The combination of SK and 4-OHT shows highly efficient anticancer effects on breast cancer therapy. SK may be a promising candidate as an adjuvant to 4-OHT for breast cancer treatments, especially for ER- breast cancer.

DHEAS prevents pro-metastatic and proliferative effects of 17ß-estradiol on MCF-7 breast cancer cells

It is generally assumed that circulating dehydroepiandrosterone sulfate (DHEAS) can be desulfated and further metabolized to estrogen, which is of concern for all patients with estrogen-responsive breast cancer. We addressed this issue by comparing the effects of DHEAS, its desulfated form DHEA, and 17ß-estradiol on human metastatic, estrogen-responsive MCF-7 breast cancer cells. Physiological concentrations of DHEAS promoted phosphorylation of Erk1/2, whereas DHEA and 17ß-estradiol failed to stimulate Erk1/2 phosphorylation, indicating that the sulfated steroid acts as an autonomous hormone. Exposure of MCF-7 cells to 17ß-estradiol stimulated cell proliferation and the expression of pro-metastatic and pro-invasive elements such as claudin-1, matrix metalloproteinase 9 (MMP9), and the CC chemokine ligand 2 (CCL2). In contrast, treatment with DHEAS did not stimulate these responses but prevented all of the actions of 17ß-estradiol, and as a consequence cell migration and invasion were completely inhibited. The results of this study not only challenge the assumption that DHEAS poses a danger as an endogenous source of estrogen, they rather favor the idea that keeping DHEAS levels within a physiological range might be supportive in treating estrogen-responsive breast cancer.

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.

Ethoxy mansonone G as an anticancer agent in estrogen receptor-positive and endocrine-resistant breast cancer

OBJECTIVES

To study anticancer effects, underlying mechanism and safety of ethoxy mansonone G (EMG) which is the potent derivative of mansonone G (MG) in breast cancer cells.

METHODS

Anticancer, antimigration, anti-invasion effects and anchorage-independent growth were investigated by MTT, scratch, matrigel invasion and soft agar assays. Estrogen receptor (ER)-targeted genes and endocrine-resistant genes were assessed by RT-PCR and Western blot.

KEY FINDINGS

Ethoxy mansonone G is the most potent MG derivative and has anticancer effects in ER-positive, endocrine-resistant and ER-negative breast cancer cells. Our results demonstrated that EMG can significantly inhibit estrogen-induced cell proliferation and the expression of ER-targeted genes in ER-positive breast cancer cells, suggesting the anti-estrogenic property of EMG which is consisting with the virtual molecular docking that EMG could possibly bind to the ERα. Moreover, EMG has synergistic effect with tamoxifen in endocrine-resistant cells. EMG also inhibited cell proliferation, invasion and anchorage-independent growth by reducing expression of genes involved in endocrine resistance and invasive factors during the metastatic process.

CONCLUSION

Ethoxy mansonone G has an anticancer effect in breast cancer cells and is possible to use as a therapeutic agent in patients with breast cancer.

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.

Wound Healing and the Use of Medicinal Plants

Cutaneous wound healing is the process by which skin repairs itself. It is generally accepted that cutaneous wound healing can be divided into 4 phases: haemostasis, inflammation, proliferation, and remodelling. In humans, keratinocytes re-form a functional epidermis (reepithelialization) as rapidly as possible, closing the wound and reestablishing tissue homeostasis. Dermal fibroblasts migrate into the wound bed and proliferate, creating “granulation tissue” rich in extracellular matrix proteins and supporting the growth of new blood vessels. Ultimately, this is remodelled over an extended period, returning the injured tissue to a state similar to that before injury. Dysregulation in any phase of the wound healing cascade delays healing and may result in various skin pathologies, including nonhealing, or chronic ulceration. Indigenous and traditional medicines make extensive use of natural products and derivatives of natural products and provide more than half of all medicines consumed today throughout the world. Recognising the important role traditional medicine continues to play, we have undertaken an extensive survey of literature reporting the use of medical plants and plant-based products for cutaneous wounds. We describe the active ingredients, bioactivities, clinical uses, formulations, methods of preparation, and clinical value of 36 medical plant species. Several species stand out, including Centella asiatica, Curcuma longa, and Paeonia suffruticosa, which are popular wound healing products used by several cultures and ethnic groups. The popularity and evidence of continued use clearly indicates that there are still lessons to be learned from traditional practices. Hidden in the myriad of natural products and derivatives from natural products are undescribed reagents, unexplored combinations, and adjunct compounds that could have a place in the contemporary therapeutic inventory.

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.

Shikonin Inhibits Tumor Growth in Mice by Suppressing Pyruvate Kinase M2-mediated Aerobic Glycolysis

Shift metabolism profile from mitochondrial oxidative phosphorylation to aerobic glycolysis (Warburg effect) is a key for tumor cell growth and metastasis. Therefore, suppressing the tumor aerobic glycolysis shows a great promise in anti-tumor therapy. In the present study, we study the role of shikonin, a naphthoquinone isolated from the traditional Chinese medicine Lithospermum, in inhibiting tumor aerobic glycolysis and thus tumor growth. We found that shikonin dose-dependently inhibited glucose uptake and lactate production in Lewis lung carcinoma (LLC) and B16 melanoma cells, confirming the inhibitory effect of shikonin on tumor aerobic glycolysis. Treatment of shikonin also decreased tumor cell ATP production. Furthermore, pyruvate kinase M2 (PKM2) inhibitor or activator respectively altered the effect of shikonin on tumor cell aerobic glycolysis, suggesting that suppression of cell aerobic glycolysis by shikonin is through decreasing PKM2 activity. Western blot analysis confirmed that shikonin treatment reduced tumor cell PKM2 phosphorylation though did not reduce total cellular PKM2 level. In vitro assay also showed that shikonin treatment significantly promoted tumor cell apoptosis compared to untreated control cells. Finally, when mice implanted with B16 cells were administered with shikonin or control vehicle, only shikonin treatment significantly decreased B16 tumor cell growth. In conclusion, this study demonstrates that shikonin inhibits tumor growth in mice by suppressing PKM2-mediated aerobic glycolysis.

Impairment of the Gnα11-controlled expression of claudin-1 and MMP-9 and collective migration of human breast cancer MCF-7 cells by DHEAS

Although dehydroepiandrosterone sulfate (DHEAS) constitutes the most abundant steroid in humans, in-depth investigations of its effects are rather scarce. We address here DHEAS effects on the estrogen receptor-positive metastatic human breast cancer cell line MCF-7. We focus on DHEAS-mediated signaling that might influence expression of claudin-1 and matrix metalloproteinase-9 (MMP-9), both known to be critical factors for migration and invasiveness of various cancers, including breast cancer cells. Physiological concentrations of DHEAS trigger persistent phosphorylation of Erk1/2 in MCF-7 cells. Exposure of these cells for 24 h to 1 μM DHEAS also leads to a significant reduction of claudin-1 expression that cannot be prevented by high concentrations of the steroid sulfatase inhibitor STX64, indicating that desulfation and further conversion of DHEAS to some other steroid hormone is not required for this action. In addition, exposure of MCF-7 cells to the same concentration of DHEAS completely abolishes MMP-9 expression and considerably impairs cell migratory behavior. Abrogation of Gnα11 expression by siRNA prevents the stimulatory effect of DHEAS on Erk1/2 phosphorylation, consistent with a G-protein-coupled receptor being involved in the DHEAS-induced signaling. Nevertheless, Gnα11 also has direct effects that do not depend on DHEAS; thus, when Gnα11 expression is suppressed, expression of claudin-1 and MMP-9 as well as cell migration are significantly reduced. This is the first report demonstrating direct involvement of DHEAS and Gnα11 in the regulation of claudin-1 and MMP-9 expression and migration of MCF-7 cells.

Photo-modulation of zinc phthalocyanine-treated breast cancer cell line ZR-75-1 inhibited the normal tumor activity in vitro

Regarding post-complication of convenient therapies against breast cancer, the emergence of effective approaches is essential. Photodynamic therapy is touted as a novel invasive therapeutic approach by the application of a photosensitizer promoted by laser irradiation. This study aimed to investigate the combined regime of low-level laser irradiation with zinc phthalocyanine in human breast cancer ZR-75-1 cell line. Cells were treated with 0.01 and 5 μg/ml of ZnPc for 24 h and exposed to radiation (70 mW) for 60 s. Cell viability was evaluated by MTT and flow cytometry. Cell migration capacity was monitored by scratch test, Transwell migration insert, and gelatin zymography. The function of MDR in treated cells was examined by Rhodamine 123 exclusion test. The level of GALNT11 was measured by ELISA. The expression of Bax and Bcl-2 genes was evaluated by real-time PCR. Laser irradiation and zinc phthalocyanine induced cell cytotoxicity in a dose-dependent manner. Flow cytometry analysis showed the induction of apoptotic and necrotic changes in treated cells. We found a reduction in migration rate and MMP-9 activity in cells undergoing the experimental procedure (p < 0.05). Immunofluorescence imaging revealed the intracellular accumulation of Rhodamine 123 coincided with a reduction in the level of GALNT11 in treated cells, showing the reduction of MDR activity and tumor cell resistance. Similar to flow cytometry assay, the reduction of Bcl-2 (approximately twofold) and upregulation of Bax genes were found in treated cells. Photodynamic therapy could be as an effective and alternative method for the treatment of breast cancer in a human.

Shikonin suppresses proliferation and induces apoptosis in endometrioid endometrial cancer cells via modulating miR-106b/PTEN/AKT/mTOR signaling pathway

Shikonin, a natural naphthoquinone isolated from a traditional Chinese medicinal herb, which exerts anticancer effects in various cancers. However, the molecular mechanisms underlying the therapeutic effects of shikonin against endometrioid endometrial cancer (EEC) have not yet been fully elucidated. Herein, we investigated anticancer effects of shikonin on EEC cells and explored the underlying molecular mechanism. We observed that shikonin inhibits proliferation in human EEC cell lines in a dose-dependent manner. Moreover, shikonin-induced apoptosis was characterized by the up-regulation of the pro-apoptotic proteins cleaved-Caspase-3 and Bax, and the down-regulation of the anti-apoptotic protein Bcl-2. Microarray analyses demonstrated that shikonin induces many miRNAs' dysregulation, and miR-106b was one of the miRNAs being most significantly down-regulated. miR-106b was identified to exert procancer effect in various cancers, but in EEC remains unclear. We first confirmed that miR-106b is up-regulated in EEC tissues and cells, and knockdown of miR-106b suppresses proliferation and promotes apoptosis. Meanwhile, our results validated that the restored expression of miR-106b abrogates the antiproliferative and pro-apoptotic effects of shikonin. We also identified that miR-106b targets phosphatase and tensin homolog (PTEN), a tumor suppressor gene, which in turn modulates AKT/mTOR signaling pathway. Our findings indicated that shikonin inhibits proliferation and promotes apoptosis in human EEC cells by modulating the miR-106b/PTEN/AKT/mTOR signaling pathway, suggesting shikonin could act a potential therapeutic agent in the EEC treatment.

Natural Products for the Management and Prevention of Breast Cancer

Among all types of cancer, breast cancer is one of the most challenging diseases, which is responsible for a large number of cancer related deaths. Hormonal therapy, surgery, chemotherapy, and radiotherapy have been used as treatment of breast cancer, for a very long time. Due to severe side effects and multidrug resistance, these treatment approaches become increasingly ineffective. However, adoption of complementary treatment approach can be a big solution for this situation, as it is evident that compounds derived from natural source have a great deal of anticancer activity. Natural compounds can fight against aggressiveness of breast cancer, inhibit cancerous cell proliferation, and modulate cancer related pathways. A large number of research works are now focusing on the natural and dietary compounds and trying to find out new and more effective treatment strategies for the breast cancer patients. In this review, we discussed some significant natural chemical compounds with their mechanisms of actions, which can be very effective against the breast cancer and can be more potent by their proper modifications and further clinical research. Future research focusing on the natural anti-breast-cancer agents can open a new horizon in breast cancer treatment, which will play a great role in enhancing the survival rate of breast cancer patients.

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.

Anticancer Efficacy of Targeted Shikonin Liposomes Modified with RGD in Breast Cancer Cells

Shikonin (SHK) has been proven to have a good anti-tumor effect. However, poor water solubility and low bioavailability limit its wide application in clinical practice. In this study, to overcome these drawbacks, RGD-modified shikonin-loaded liposomes (RGD-SSLs-SHK) were successfully prepared. It exhibited excellent physicochemical characteristics including particle size, zeta potential, encapsulation efficiency, and delayed release time. Meanwhile, the targeting activity of the RGD-modified liposomes was demonstrated by flow cytometry and confocal microscopy in the α_vβ₃-positive MDA-MB-231 cells. Besides exhibiting greater cytotoxicity in vitro, compared with non-targeted shikonin-loaded liposomes (SSLs-SHK), RGD-SSLs-SHK could also evidently induce apoptosis by decreasing the expression of Bcl-2 and increasing the expression of Bax. It could also inhibit cell proliferation, migration, invasion, and adhesion by reducing the expression of MMP-9 and the level of NF-κB p65, but did not affect the expression of MMP-2 in the MDA-MB-231 cells. Therefore, these findings indicated that the strategy to use RGD-modified liposomes as carriers for targeted delivery of shikonin is a very promising approach to achieve breast cancer targeted therapy.

Successful in vivo hyperthermal therapy toward breast cancer by Chinese medicine shikonin-loaded thermosensitive micelle

The Chinese traditional medicine Shikonin is an ideal drug due to its multiple targets to tumor cells. But in clinics, improving its aqueous solubility and tumor accumulation is still a challenge. Herein, a copolymer with tunable poly(N-isopropylacrymaide) and polylactic acid block lengths is designed, synthesized, and characterized in nuclear magnetic resonance. The corresponding thermosensitive nanomicelle (TN) with well-defined core-shell structure is then assembled in an aqueous solution. For promoting the therapeutic index, the physical-chemistry properties of TNs including narrow size, low critical micellar concentration, high serum stability, tunable volume phase transition temperature (VPTT), high drug-loading capacity, and temperature-controlled drug release are systematically investigated and regulated through the fine self-assembly. The shikonin is then entrapped in a degradable inner core resulting in a shikonin-loaded thermosensitive nanomicelle (STN) with a VPTT of ~40°C. Compared with small-molecular shikonin, the in vitro cellular internalization and cytotoxicity of STN against breast cancer cells (Michigan Cancer Foundation-7) are obviously enhanced. In addition, the therapeutic effect is further enhanced by the programmed cell death (PCD) specifically evoked by shikonin. Interestingly, both the proliferation inhibition and PCD are synergistically promoted as T > VPTT, namely the temperature-regulated passive targeting. Consequently, as intravenous injection is administered to the BALB/c nude mice bearing breast cancer, the intratumor accumulation of STNs is significantly increased as T > VPTT, which is regulated by the in-house developed heating device. The in vivo antitumor assays against breast cancer further confirm the synergistically enhanced therapeutic efficiency. The findings of this study indicate that STN is a potential effective nanoformulation in clinical cancer therapy.

Solamargine inhibits the migration and invasion of HepG2 cells by blocking epithelial-to-mesenchymal transition

Solamargine (SM), a steroidal alkaloid glycoside purified from the Chinese traditional herb Solanum incanum, is known to possess various biological activities. However, only a few previous studies have reported the anti-metastatic activity of SM. In the present study, the inhibitory effects of SM on metastatic action were investigated in human HepG2 cells. The proliferation effects of SM on the HepG2 cells was evaluated by MTT and colony formation assays. Wound-healing and Transwell assays were performed to examine the migration and invasion effects on SM-treated HepG2 cells. The epithelial-to-mesenchymal transition (EMT)-associated markers (E-cadherin, Vimentin and N-cadherin) were detected by western blotting analysis. In the present study, MTT and colony formation assays indicated that SM suppressed HepG2 cell viability in a dose-dependent manner. The wound-healing and Transwell assays revealed that the migration and invasion activities were significantly inhibited following exposure to SM. EMT has been demonstrated to be essential for promoting migration and invasion in tumor cells and has often been characterized with a loss of epithelial markers (E-cadherin) and an increase of mesenchymal markers (Vimentin and N-cadherin). In the western blotting analysis, the expression level of E-cadherin was significantly upregulated compared with that in the control group, whereas the expression levels of N-cadherin and Vimentin were downregulated. Thus, it was suggested that the underlying mechanism of SM inhibits migration and invasion in HepG2 cells and is associated with suppression of EMT.

Natural Compounds As Modulators of Non-apoptotic Cell Death in Cancer Cells

Cell death is an innate capability of cells to be removed from microenvironment, if and when they are damaged by multiple stresses. Cell death is often regulated by multiple molecular pathways and mechanism, including apoptosis, autophagy, and necroptosis. The molecular network underlying these processes is often intertwined and one pathway can dynamically shift to another one acquiring certain protein components, in particular upon treatment with various drugs. The strategy to treat human cancer ultimately relies on the ability of anticancer therapeutics to induce tumor-specific cell death, while leaving normal adjacent cells undamaged. However, tumor cells often develop the resistance to the drug-induced cell death, thus representing a great challenge for the anticancer approaches. Numerous compounds originated from the natural sources and biopharmaceutical industries are applied today in clinics showing advantageous results. However, some exhibit serious toxic side effects. Thus, novel effective therapeutic approaches in treating cancers are continued to be developed. Natural compounds with anticancer activity have gained a great interest among researchers and clinicians alike since they have shown more favorable safety and efficacy then the synthetic marketed drugs. Numerous studies in vitro and in vivo have found that several natural compounds display promising anticancer potentials. This review underlines certain information regarding the role of natural compounds from plants, microorganisms and sea life forms, which are able to induce non-apoptotic cell death in tumor cells, namely autophagy and necroptosis.

Shikonin Inhibits the Proliferation of Human Breast Cancer Cells by Reducing Tumor-Derived Exosomes

Shikonin is a naphthoquinone isolated from the traditional Chinese medicine Lithospermum. It has been used in the treatment of various tumors. However, the effects of shikonin on such diseases have not been fully elucidated. In the present study, we detected the exosome release of a breast cancer cell line (MCF-7) with shikonin treatment and found a positive relationship between the level of secreted exosomes and cell proliferation. We next analyzed miRNA profiles in MCF-7 cells and exosomes and found that some miRNAs are specifically sorted and abundant in exosomes. Knockdown of the most abundant miRNAs in exosomes and the MCF-7 proliferation assay showed that miR-128 in exosomes negatively regulates the level of Bax in MCF-7 recipient cells and inhibits cell proliferation. These results show that shikonin inhibits the proliferation of MCF-7 cells through reducing tumor-derived exosomal miR-128. The current study suggests that shikonin suppresses MCF-7 growth by the inhibition of exosome release.

RIP1K and RIP3K provoked by shikonin induce cell cycle arrest in the triple negative breast cancer cell line, MDA-MB-468: necroptosis as a desperate programmed suicide pathway

Resistance to cell death and reprogramming of metabolism are important in neoplastic cells. Increased resistance to apoptosis and recurrence of tumors are the major roadblocks to effective treatment of triple negative breast cancer. It has been thought that execution of necroptosis involves ROS generation and mitochondrial dysfunction in malignant cells. In this study, the effect of shikonin, an active substance from the dried root of Lithospermum erythrorhizon, on the induction of necroptosis or apoptosis, via RIP1K-RIP3K expressions has been examined in the triple negative breast cancer cell line. The expression levels of RIP1K and RIP3K, caspase-3 and caspase-8 activities, the levels of ROS, and mitochondrial membrane potential have been studied in the shikonin-treated MDA-MB-468 cell line. An increase in the ROS levels and a reduction in mitochondrial membrane potential have been observed in the shikonin-treated cells. Cell death has mainly occurred through necroptosis with a significant increase in the RIP1K and RIP3K expressions, and characteristic morphological changes have been observed. In the presence of Nec-1, caspase-3 mediating apoptosis has occurred in the shikonin-treated cells. The current findings have revealed that shikonin provoked mitochondrial ROS production in the triple negative breast cancer cell line, which works as a double-edged executioner's ax in the execution of necroptosis or apoptosis. The main route of cell death induced by shikonin is RIP1K-RIP3K-mediated necroptosis, but in the presence of Nec-1, apoptosis has prevailed. The present results shed a new light on the possible treatment of drug-resistant triple negative breast cancer.

Shikonin as an inhibitor of the LPS-induced epithelial-to-mesenchymal transition in human breast cancer cells

Shikonin (SK), a natural naphthoquinone isolated from the Chinese medicinal herb, has been known to suppress the proliferation of several cancer cells. However, its role in the epithelial mesenchymal transition (EMT) has yet to be demonstrated. The aim of the present study was to examine the effects of SK on EMT. Lipopolysaccharide (LPS) induced EMT-like phenotypic changes, enhancing cell migration and invasion. SK markedly reduced the expression of the LPS-induced EMT markers, including N-cadherin in MDA-MB‑231 cells, and increased the expression of E-cadherin in MCF-7 cells. SK also inhibited cell migration and invasion in vitro. The effects of SK on the LPS-induced EMT were mediated by the inactivation of the NF-κB-Snail signaling pathway. The results provided new evidence that SK suppresses breast cancer cell invasion and migration by inhibiting the EMT. Therefore, SK is a potentially effective anticancer agent for breast tumors, by inhibiting metastasis.

Shikonin Inhibits the Migration and Invasion of Human Glioblastoma Cells by Targeting Phosphorylated β-Catenin and Phosphorylated PI3K/Akt: A Potential Mechanism for the Anti-Glioma Efficacy of a Traditional Chinese Herbal Medicine

Shikonin is an anthraquinone derivative extracted from the root of lithospermum. Shikonin is traditionally used in the treatment of inflammatory and infectious diseases such as hepatitis. Shikonin also inhibits proliferation and induces apoptosis in various tumors. However, the effect of shikonin on gliomas has not been fully elucidated. In the present study, we aimed to investigate the effects of shikonin on the migration and invasion of human glioblastoma cells as well as the underlying mechanisms. U87 and U251 human glioblastoma cells were treated with shikonin at 2.5, 5, and 7.5 μmol/L and cell viability, migration and invasiveness were assessed with CCK8, scratch wound healing, in vitro Transwell migration, and invasion assays. The expression and activity of matrix metalloproteinase-2 (MMP-2) and matrix metalloproteinase-9 (MMP-9) and the expression of phosphorylated β-catenin (p-β-catenin) and phosphorylated PI3K/Akt were also checked. Results showed that shikonin significantly inhibited the cell proliferation, migration, invasion, and expression of MMP-2 and MMP-9 in U87 and U251 cells. The expression of p-β-catenin showed contrary trends in two cell lines. It was significantly inhibited in U87 cells and promoted in U251 cells. Results in this work indicated that shikonin displayed an inhibitory effect on the migration and invasion of glioma cells by inhibiting the expression and activity of MMP-2 and -9. In addition, shikonin also inhibited the expression of p-PI3K and p-Akt to attenuate cell migration and invasion and MMP-2 and MMP-9 expression in both cell lines, which could be reversed by the PI3K/Akt pathway agonist, insulin-like growth factor-1 (IGF-1).

Investigating the potential of Shikonin as a novel hypertrophic scar treatment

Background

Hypertrophic scarring is a highly prevalent condition clinically and results from a decreased number of apoptotic fibroblasts and over-abundant production of collagen during scar formation following wound healing. Our previous studies indicated that Shikonin, an active component extracted from Radix Arnebiae, induces apoptosis and reduces collagen production in hypertrophic scar-derived fibroblasts. In the study reported here, we further evaluate the potential use of Shikonin as a novel scar remediation therapy by examining the effects of Shikonin on both keratinocytes and fibroblasts using Transwell® co-culture techniques. The underlying mechanisms were also revealed. In addition, effects of Shikonin on the expression of cytokines in Transwell co-culture “conditioned” medium were investigated.

Results

Our results indicate that Shikonin preferentially inhibits cell proliferation and induces apoptosis in fibroblasts without affecting keratinocyte function. In addition, we found that the proliferation-inhibiting and apoptosis-inducing abilities of SHI might be triggered via MAPK and Bcl-2/Caspase 3 signalling pathways. Furthermore, SHI has been found to attenuate the expression of TGF-β1 in Transwell co-cultured “conditioned” medium.

Conclusions

The data generated from this study provides further evidence that supports the potential use of Shikonin as a novel scar remediation therapy.

Shikonin inhibits TNF-α-induced growth and invasion of rat aortic vascular smooth muscle cells

Shikonin is a naphthoquinone compound extracted from the Chinese herb purple gromwell. Shikonin has broad antibacterial, anti-inflammatory, and antitumor activities. The tumor necrosis factor-α (TNF-α)-induced proliferation and invasion of vascular smooth muscle cells (VSMCs) is an important factor that contributes to atherosclerosis. The effects of shikonin on the proliferation and apoptosis of VSMCs have been reported; however, the function of shikonin on TNF-α-mediated growth and invasion of VSMCs during atherosclerosis remains unclear. In this study, we used Western blot, flow cytometry, real-time quantitative PCR, and enzyme-linked immunosorbent assay to investigate the effect of shikonin on the TNF-α-induced growth and invasion of VSMCs and to determine the underlying mechanism. Our results showed that shikonin inhibits the TNF-α-mediated growth and invasion. Further study revealed that shikonin regulates the activation of nuclear factor kappa B and phosphatidyl inositol 3-kinase signaling pathways; modulates the expression of cyclin D1, cyclin E, B-cell lymphoma 2, and Bax; activates caspase-3 and caspase-9; induces cell cycle arrest; and promotes the apoptosis of VSMCs. Together, our results indicate that shikonin may become a promising agent for the treatment of atherosclerosis and they also establish foundation for the development of anti-atherosclerosis drugs.

Effects of psoralens as anti-tumoral agents in breast cancer cells

This review examines the biological properties of coumarins, widely distributed at the highest levels in the fruit, followed by the roots, stems and leaves, by considering their beneficial effects in the prevention of some diseases and as anti-cancer agents. These compounds are well known photosensitizing drugs which have been used as pharmaceuticals for a broad number of therapeutic applications requiring cell division inhibitors. Despite this, even in the absence of ultraviolet rays they are active. The current paper mainly focuses on the effects of psoralens on human breast cancer as they are able to influence many aspects of cell behavior, such as cell growth, survival and apoptosis. In addition, analytical and pharmacological data have demonstrated that psoralens antagonize some metabolizing enzymes, affect estrogen receptor stability and counteract cell invasiveness as well as cancer drug resistance. The scientific findings summarized highlight the pleiotropic functions of phytochemical drugs, given that recently their target signals and how these are modified in the cells have been identified. The encouraging results in this field suggest that multiple modulating strategies based on coumarin drugs in combination with canonical chemotherapeutic agents or radiotherapy could be a useful approach to address the treatment of many types of cancer.