Synergistic effects of baicalein with gemcitabine or docetaxel on the proliferation, migration and apoptosis of pancreatic cancer cells

The most recent progress of baicalein in its anti-neoplastic effects and mechanisms

Problems, such as toxic side effects and drug resistance of chemoradiotherapy, target therapy and immunotherapy accompanying the current anti-cancer treatments, have become bottlenecks limiting the clinical benefit for patients. Therefore, it is urgent to find promising anti-cancer strategies with higher efficacy and lesser side effects. Baicalein, a flavonoid component derived from the Chinese medicine scutellaria baicalensis, has been widely studied for its remarkable anti-cancer activity in multiple types of malignancies both at the molecular and cellular levels. Baicalein exerts its anti-tumor effects by inhibiting angiogenesis, invasion and migration, inducing cell apoptosis and cell cycle arrest, as well as regulating cell autophagy, metabolism, the tumor microenvironment and cancer stem cells with no obvious toxic side effects. The role of classic signaling pathways, such as PI3K/AKT/mTOR, MAPK, AMPK, Wnt/β-catenin, JAK/STAT3, MMP-2/-9, have been highlighted as the major targets for baicalein exerting its anti-malignant potential. Besides, baicalein can regulate the relevant non-coding RNAs, such as lncRNAs, miRNAs and circ-RNAs, to inhibit tumorigenesis and progression. In addition to the mentioned commonalities, baicalein shows some specific anti-tumor characteristics in some specific cancer types. Moreover, the preclinical studies of the combination of baicalein and chemoradiotherapy pave the way ahead for developing baicalein as an adjunct treatment with chemoradiotherapy. Our aim is to summary the role of baicalein in different types of cancer with its mechanisms based on in vitro and in vivo experiments, hoping providing proof for baicalein serving as an effective and safe compound for cancer treatment in clinic in the future.

Functional structural domain synthesis of anti-pancreatic carcinoma pectin-like polysaccharide RN1

The great structural and functional diversity supports polysaccharides as favorable candidates for new drug development. Previously we reported that a drug candidate pectin-like natural polysaccharide, RN1 might target galectin-3 (Gal-3) to impede pancreatic cancer cell growth in vivo. However, the quality control of polysaccharide-based drug research faces great challenges due to the heterogeneity. A potential solution is to synthesize structurally identified subfragments of this polysaccharide as alternatives. In this work, we took RN1 as an example, and synthesized five subfragments derived from the putative repeating units of RN1. Among them, pentasaccharide 4 showed an approximative binding affinity to Gal-3 in vitro, as well as an antiproliferative activity against pancreatic BxPC-3 cells comparable to that of RN1. Further, we scaled up pentasaccharide 4 to gram-scale in an efficient synthetic route with a 6.9 % yield from D-galactose. Importantly, pentasaccharide 4 significantly suppressed the growth of pancreatic tumor in vivo. Based on the mechanism complementarity of galactin-3 inhibitor and docetaxel, the combination administration of pentasaccharide 4 and docetaxel afforded better result. The result suggested pentasaccharide 4 was one of the functional structural domains of polysaccharide RN1 and might be a leading compound for anti-pancreatic cancer new drug development.

Anticancer Effect by Combined Treatment of Artemisia annua L. Polyphenols and Docetaxel in DU145 Prostate Cancer Cells and HCT116 Colorectal Cancer Cells

Docetaxel (DTX), a semi-synthetic analogue of paclitaxel (taxol), is known to exert potent anticancer activity in various cancer cells by suppressing normal microtubule dynamics. In this study, we examined how the anticancer effect of DTX is regulated by polyphenols extracted from Korean Artemisia annua L. (pKAL) in DU145 prostate cancer cells (mutant p53) and HCT116 colorectal cancer cells (wild-type p53). Here, we show that the anticancer effect of DTX was enhanced more significantly by pKAL in HCT116 cells than in DU145 cells via phase-contrast microscopy, CCK-8 assay, Western blot, and flow cytometric analysis of annexin V/propidium iodide-stained cells. Notably, mutant p53 was slightly downregulated by single treatment of pKAL or DTX in DU145 cells, whereas wild-type p53 was significantly upregulated by pKAL or DTX in HCT116 cells. Moreover, the enhanced anticancer effect of DTX by pKAL in HCT116 cells was significantly associated with the suppression of DTX-induced p53 upregulation, increase of DTX-induced phospho-p38, and decrease of DTX-regulated cyclin A, cyclin B1, AKT, caspase-8, PARP1, GM130, NF-κB p65, and LDHA, leading to the increased apoptotic cell death and plasma membrane permeability. Our results suggest that pKAL could effectively improve the anticancer effect of DTX-containing chemotherapy used to treat various cancers expressing wild-type p53.

Oral metronomic therapy of pancreatic cancer with gemcitabine and paclitaxel co-loaded in lecithin-based Self-Nanoemulsifying preconcentrate (LBSNEP)

This study aimed to evaluate gemcitabine (GEM)/paclitaxel (PTX) co-loaded into a lecithin-based self-nanoemulsifying preconcentrate (LBSNEP) orally administered in a metronomic therapeutic manner against pancreatic cancer. LBSNEP was developed and evaluated, composed of Caproyl 90, Tween80, lecithin, TPGS, and propyl glycol at a ratio of 20:20:30:5:25, resulting in a droplet diameter of approximately 180 nm. Cell viability studies on MIA PaCa-2 demonstrated a synergetic effect at a proportion of 1:2 between PTX and GEM. Additionally, LBSNEP and baicalein (BAI) were demonstrated to prevent GEM from being deaminated by cytidine deaminase. The combination of GEM, PTX, and BAI in the LBSNEP showed good dissolution in simulated gastric fluid. The pharmacokinetic study conducted on rats showed that co-administration of GEM, PTX, and BAI in the LBSNEP enhanced the respective relative oral bioavailability levels of GEM and PTX by 1.5- and 2-fold, respectively, compared to the solution group. The tumor inhibition study was conducted with metronomic therapy at a low daily dose compared to conventional therapy at a higher dose every 3 days. Results indicated that oral metronomic delivery of GEM/PTX/BAI LBSNEP could inhibit tumor growth during administration phase, and that there were similar tumor volumes compared to traditional chemotherapy at day 28 even if the dose of metronomic chemotherapy was 2.2-fold less than that of the latter. In conclusion, a self-nanoemulsifying drug-delivery system for the oral delivery of GEM, PTX, and BAI in a metronomic manner enhanced the therapeutic effect on pancreatic cancer, providing an alternative option for chemotherapy.

Promising Role of the Scutellaria baicalensis Root Hydroxyflavone-Baicalein in the Prevention and Treatment of Human Diseases

Plant roots, due to a high content of natural antioxidants for many years, have been used in herbal medicine. It has been documented that the extract of Baikal skullcap (Scutellaria baicalensis) has hepatoprotective, calming, antiallergic, and anti-inflammatory properties. Flavonoid compounds found in the extract, including baicalein, have strong antiradical activity, which improves overall health and increases feelings of well-being. Plant-derived bioactive compounds with antioxidant activity have for a long time been used as an alternative source of medicines to treat oxidative stress-related diseases. In this review, we summarized the latest reports on one of the most important aglycones with respect to the pharmacological activity and high content in Baikal skullcap, which is 5,6,7-trihydroxyflavone (baicalein).

Targeting Apoptotic Pathway of Cancer Cells with Phytochemicals and Plant-Based Nanomaterials

Apoptosis is the elimination of functionally non-essential, neoplastic, and infected cells via the mitochondrial pathway or death receptor pathway. The process of apoptosis is highly regulated through membrane channels and apoptogenic proteins. Apoptosis maintains cellular balance within the human body through cell cycle progression. Loss of apoptosis control prolongs cancer cell survival and allows the accumulation of mutations that can promote angiogenesis, promote cell proliferation, disrupt differentiation, and increase invasiveness during tumor progression. The apoptotic pathway has been extensively studied as a potential drug target in cancer treatment. However, the off-target activities of drugs and negative implications have been a matter of concern over the years. Phytochemicals (PCs) have been studied for their efficacy in various cancer cell lines individually and synergistically. The development of nanoparticles (NPs) through green synthesis has added a new dimension to the advancement of plant-based nanomaterials for effective cancer treatment. This review provides a detailed insight into the fundamental molecular pathways of programmed cell death and highlights the role of PCs along with the existing drugs and plant-based NPs in treating cancer by targeting its programmed cell death (PCD) network.

The Multifaceted Role of Baicalein in Cancer Management through Modulation of Cell Signalling Pathways

The roles of medicinal plants or their purified bioactive compounds have attracted attention in the field of health sciences due to their low toxicity and minimal side effects. Baicalein is an active polyphenolic compound, isolated from Scutellaria baicalensis, and plays a significant role in the management of different diseases. Epidemiologic studies have proven that there is an inverse association between baicalein consumption and disease severity. Baicalein is known to display anticancer activity through the inhibition of inflammation and cell proliferation. Additionally, the anticancer potential of baicalein is chiefly mediated through the modulation of various cell-signaling pathways, such as the induction of apoptosis, autophagy, cell cycle arrest, inhibition of angiogenesis, signal transducer and activator of transcription 3, and PI3K/Akt pathways, as well as the regulation of other molecular targets. Therefore, the current review aimed to explore the role of baicalein in different types of cancer along with mechanisms of action. Besides this, the synergistic effects with other anti-cancerous drugs and the nano-formulation based delivery of baicalein have also been discussed.

Drug-herb interactions between Scutellaria baicalensis and pharmaceutical drugs: Insights from experimental studies, mechanistic actions to clinical applications

Whilst the popular use of herbal medicine globally, it poses challenges in managing potential drug-herb interaction. There are two folds of the drug-herb interaction, a beneficial interaction that may improve therapeutic outcome and minimise the toxicity of drug desirably; by contrast, negative interaction may evoke unwanted clinical consequences, especially with drugs of narrow therapeutic index. Scutellaria baicalensis Georgi is one of the most popular medicinal plants used in Asian countries. It has been widely used for treating various diseases and conditions such as cancer, diabetes, inflammation, and oxidative stress. Studies on its extract and bioactive compounds have shown pharmacodynamic and pharmacokinetic interactions with a wide range of pharmaceutical drugs as evidenced by plenty of in vitro, in vivo and clinical studies. Notably, S. baicalensis and its bioactives including baicalein, baicalin and wogonin exhibited synergistic interactions with many pharmaceutical drugs to enhance their efficacy, reduce toxicity or overcome drug resistance to combat complex diseases such as cancer, diabetes and infectious diseases. On the other hand, S. baicalensis and its bioactives also affected the pharmacokinetic profile of many drugs in absorption, distribution, metabolism and elimination via the regulatory actions of the efflux pumps and cytochrome P450 enzymes. This review provides comprehensive references of the observed pharmacodynamic and pharmacokinetic drug interactions of Scutellaria baicalensis and its bioactives. We have elucidated the interaction with detailed mechanistic actions, identified the knowledge gaps for future research and potential clinical implications. Such knowledge is important for the practice of both conventional and complementary medicines, and it is essential to ensure the safe use of related herbal medicines. The review may be of great interest to practitioners, consumers, clinicians who require comprehensive information on the possible drug interactions with S. baicalensis and its bioactives.

Skullcapflavone I has a potent anti-pancreatic cancer activity by targeting miR-23a

Baicalein has been widely studied and showed a potent activity against pancreatic cancer in both in vivo and in vitro studies. Little is known regarding the effects of Skullcapflavone I (SFI), despite they have similar structures. So, this study was to explore the function of SFI on human pancreatic cancer. Panc-1 cells were transfected with miR-23a precursor, miR-23a inhibitor or the negative controls, and subsequently treated by SFI. Cell viability, Bromodeoxyuridine (BrdU)-positive cell rate, apoptosis, migration, invasion, and related protein expression were assessed by utilizing Cell Counting Kit-8 (CCK-8), BrdU staining, apoptosis assessment, transwell assay, and western blot. SFI significantly reduced the proliferation, migration, and invasion, as well as induced apoptosis of Panc-1 cells. MiR-23a, miR-21, and miR-155 were lowly expressed while miR-145 and miR-146a were highly expressed in SFI-treated cell. Of note, the antitumor effects of SFI were promoted by miR-23a suppression whereas attenuated by miR-23a overexpression. JAK/STAT and MAPK pathways were inhibited by SFI. Also, the pathway inhibition in SFI-treated cells was reversed by miR-23a overexpression. SFI might be a promising anti-pancreatic cancer agent by inhibiting cancer cells growth and motility. The anticancer activities of SFI might be through downregulation of miR-23a, as well as inhibition of JAK/STAT and MAPK pathways.

Baicalein: A metabolite with promising antineoplastic activity

Cancer, being a multifactorial disease has diverse presentation in different subgroups which is mainly attributed to heterogenous presentation of tumor cells. This cancer cell heterogeneity is the major reason for variable response to standard chemotherapeutic regimes owing to which high relapse rate and multi-drug resistance has increasingly been reported over the past decade. Interestingly, the research on natural compounds in combination with standard therapies have reported with interesting and promising results from the pre-clinical trials and few of which have also been tested in other phases of clinical trials. This review focusses on baicalein, an emerging anti-cancerous natural compound, its chemistry and mechanism of action. In view of promising pre-clinical this review is mainly motivated by the results observed from baicalein treatment of different cancer cell population. With the advancing scientific evidence on the anti-malignant potential of baicalein with respect to its pharmacological activities encompassing from anti-inflammatory to anti-angiogenic/anti-metastatic effects, the focus is mainly directed to understanding the precise mechanism of action of baicalein. In the process of understanding the underlying signaling cascades, the role of mitogen activated protein kinase (MAPK), mammalian target of rapamycin (mTOR), AKT serine/threonine protein kinase B (AKT), poly(ADP-ribose) polymerase (PARP), matrix metalloproteinases-2 (MMP-2), matrix metalloproteinases-9 (MMP-9) and caspase-3/-8,-9 have been highlighted as the major players for baicalein anti-malignant potential. This is also supported by the interesting pre-clinical findings which cumulatively pave the way ahead for development of baicalein as an adjunct anti-cancer treatment with chemotherapeutic agents.

Curcumin enhances anti‑cancer efficacy of either gemcitabine or docetaxel on pancreatic cancer cells

Curcumin is a natural compound extracted from turmeric (Curcuma longa), which has been reported to be a promising anti‑cancer drug in various human cancers. However, the effects of combination treatment of curcumin with gemcitabine or docetaxel on pancreatic cancer remains elusive. In the present study, the combinatory effects of curcumin with either gemcitabine or docetaxel on the proliferation, apoptosis, migration as well as invasion of PC cells were investigated. Calcusyn software was used to determine whether curcumin has is synergistic with gemcitabine or docetaxel. Combination index values from combinational use were all lower than 1, indicating the synergism of curcumin with gemcitabine or docetaxel on PC cells in vitro. EdU assay showed that curcumin could enhance the ability of gemcitabine or docetaxel to inhibit the proliferation of PC cells. Furthermore, the results from transmission electron microscope, DAPI staining experiments and western blot analysis revealed that curcumin may trigger apoptosis of PC cells via PARP/caspase‑3 signaling pathway and reinforced pro‑apoptotic ability of either gemcitabine or docetaxel. In addition, curcumin exhibited marked suppressive ability on metastasis of PC cells by wound healing and matrigel‑transwell assay. Mechanistically, upregulation of TIMP1/TIMP2 with concomitant downregulation of MMP2/MMP9/N‑cadherin proteins may be involved in this process. In conclusion, curcumin showed synergistic anti‑cancer effects with either gemcitabine or docetaxel on PC cells.

WITHDRAWN: Skullcapflavone I has a potent anti-pancreatic cancer activity by targeting miR-23a

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Effects of baicalein on pancreatic cancer stem cells via modulation of sonic Hedgehog pathway

Recent studies have suggested that sonic Hedgehog (Shh) signaling pathway is aberrantly activated in cancer stem cells (CSCs). A seven-herb Chinese medicinal formula composed of Amorphophallus rivieri Durieu, Oldenlandia diffusa (Wild) Roxb, Scutellaria barbata D. Don, Gynostemma pentaphyllum (Thunb.) Mak and Amomum cardamomum L, i.e. Qingyihuaji (QYHJ) formula, has been shown to inhibit proliferation of pancreatic CSCs by inhibiting Shh signaling pathway and thereby prolong the overall survival of pancreatic cancer patients. Mass spectrometry analysis revealed that baicalein is one of the major compounds of QYHJ formula. The objective of this study was to investigate the role of Shh pathway in pancreatic cancer and to examine the molecular mechanisms of baicalein involved in pancreatic cancer treatment. We examined the effects of baicalein on pancreatic CSCs both in vivo and in vitro. The results indicated that baicalein attenuated the pluripotency of pancreatic CSCs. Then, we investigated the underlying mechanism and found that nuclear transcription factors, such as Sox-2 and Oct-4 as well as members in Shh signaling pathway, e.g. SHH, SMO, and Gli-2, were downregulated after baicalein treatment. Furthermore, silencing Gli-2 expression by small interfering RNA decreased Sox-2 expression and blocked the inhibitory effects of baicalein, suggesting that the effects of baicalein may be mediated through inhibition of Shh pathway. Our results suggested that baicalein, an active compound in QYHJ formula, could suppress the self-renewal of pancreatic CSCs through inhibition of Shh signaling pathway.