Anti-tumor effect of honokiol alone and in combination with other anti-cancer agents in breast cancer

Bioinformatics and In Vitro Study Reveal ERα as The Potential Target Gene of Honokiol to Enhance Trastuzumab Sensitivity in HER2+ Trastuzumab-Resistant Breast Cancer Cells

Trastuzumab resistance presents a significant challenge in the treatment of HER2+ breast cancer, necessitating the investigation of combination therapies to overcome this resistance. Honokiol, a compound with broad anticancer activity, has shown promise in this regard. This study aims to discover the effect of honokiol in increasing trastuzumab sensitivity in HER2+ trastuzumab-resistant breast cancer cells HCC1954 and the underline mechanisms behind. A bioinformatics study performed to explore the most potential target hub gene for honokiol in HER2+ breast cancer. Honokiol, trastuzumab and combined treatment cytotoxicity activity was then evaluated in both parental HCC1954 and trastuzumab resistance (TR-HCC1954) cells using MTT assay. The expression levels of these hub genes were then analyzed using qRT-PCR and those that could not be analyzed were subjected to molecular docking to determine their potential. Honokiol showed a potent cytotoxicity activity with an IC50 of 41.05 μM and 69.61 μM in parental HCC1954 and TR-HCC1954 cell line respectively. Furthermore, the combination of honokiol and trastuzumab resulted in significant differences in cytotoxicity in TR-HCC1954 cells at specific concentrations. Molecular docking and the qRT-PCR showed that the potential ERα identified from the bioinformatics analysis was affected by the treatment. Our results show that honokiol has the potential to increase the sensitivity of trastuzumab in HER2+ trastuzumab resistant breast cancer cell line HCC1954 by affecting regulating estrogen receptor signaling. Further research is necessary to validate these findings.

Glutathione-responsive CD-MOFs co-loading honokiol and indocyanine green biomimetic active targeting to enhance photochemotherapy for breast cancer

Breast cancer has now replaced lung cancer as the most prevalent malignant tumor worldwide, posing a serious health risk to women. We have recently designed a promising option strategy for the treatment of breast cancer. In this work, cyclodextrin metal-organic frameworks with high drug-carrying properties were endo-crosslinked by 3,3'dithiodipropionyl chloride to form cubic phase gel nanoparticles, which were drug-loaded and then coated by MCF-7 cell membranes. After intravenous injection, this multifunctional nanomedicine achieved dramatically homologous targeting co-delivery of honokiol and indocyanine green to the breast tumor. Further, the disulfide bonds in the nanostructures achieved glutathione-responsive drug release, induced tumor cells to produce reactive oxygen species and promoted apoptosis, resulting in tumor necrosis, and at the same time, inhibited Ki67 protein expression, which enhanced photochemotherapy, and resulted in a 94.08 % in vivo tumor suppression rate in transplanted tumor-bearing mice. Thereby, this nanomimetic co-delivery system may have a place in breast cancer therapy due to its simple fabrication process, excellent biocompatibility, efficient targeted delivery of insoluble drugs, and enhanced photochemotherapy.

An integrated approach to understand the regulatory role of miR-27 family in breast cancer metastasis

One of the prime reasons of increasing breast cancer mortality is metastasizing cancer cells. Owing to the side effects of clinically available drugs to treat breast cancer metastasis, it is of utmost importance to understand the underlying biogenesis of breast cancer tumorigenesis. In-silico identification of potential RNAs might help in utilizing the miR-27 family as a therapeutic target in breast cancer. The experimentally verified common interacting mRNAs for miR27 family are retrieved from three publicly available databases- TargetScan, miRDB and miRTarBase. Finally on comparing the common genes with HCMDB and GEPIA data, four breast cancer-associated differentially expressed metastatic mRNAs (GATA3, ENAH, ITGA2 and SEMA4D) are obtained. Corresponding to the miR27 family and associated mRNAs, interacting drugs are retrieved from Sm2mir and CTDbase, respectively. The interaction network-based approach was utilized to obtain the hub RNAs and triad modules by employing the 'Cytohubba' and 'MClique' plugins, respectively in Cytoscape. Further, sample-, subclass- and promoter methylation-based expression analyses reveals GATA3 and ENAH to be the most significant mRNAs in breast cancer metastasis having >10% genetic alteration in both METABRIC Vs TCGA datasets as per their oncoprint analysis via cBioPortal. Additionally, survival analysis in Oncolnc reveals SEMA4D as survival biomarker. Interactions among the miR27 family, their target mRNAs and drugs interacting with miRNAs and mRNAs can be extensively explored in both in-vivo and in-vitro setups to assess their therapeutic potential in the diminution of breast cancer.

Upregulation of tumor suppressor PIAS3 by Honokiol promotes tumor cell apoptosis via selective inhibition of STAT3 tyrosine 705 phosphorylation

The natural product Honokiol exhibits robust antitumor activity against a range of cancers, and it has also received approval to undergo phase I clinical trial testing. We confrmed that honokiol can promote the apoptotic death of tumor cells through cell experiments. Then siRNA constructs specific for PIAS3, PIAS3 overexpression plasmid and the mutation of the STAT3 Tyr705 residue were used to confirm the mechanism of Honokiol-induced apoptosis. Finally, we confrmed that honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation through the in vivo and in vitro experiments. Honokiol was ultimately found to reduce tumor cell viability by promoting apoptosis through a mechanism dependent on the ability of Honokiol to promote PIAS3 upregulation and the selective inhibition of p-STAT3 (Tyr705) without affecting p-STAT3 (Ser727) or p-STAT1 (Tyr701) levels. PIAS3 knockdown and overexpression in tumor cells altered STAT3 activation and associated DNA binding activity through the control of Tyr705 phosphorylation via PIAS3-STAT3 complex formation, ultimately shaping Honokiol-induced tumor cell apoptosis. Honokiol was also confirmed to significantly prolong the survival of mice bearing xenograft tumors in a PIAS3-dependent fashion. Together, these findings highlight a novel pathway through which Honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation and promoting the apoptotic death of tumor cells.

Honokiol alleviates radiation-induced premature ovarian failure via enhancing Nrf2

BACKGROUND

The ovary is highly sensitive to radiation, and patients receiving radiotherapy are at significant risk of premature ovarian failure (POF). This study aimed to explore the radioprotective effect of honokiol (HKL) on ionizing radiation (IR)-induced POF.

METHODS

Female C57BL/6 mice were administered intraperitoneally with vehicle or HKL once daily for 7 days. On day 7, the mice in the IR and HKL+IR groups were exposed to 3.2 Gy whole-body radiation for one hour after the intraperitoneal injection and sacrificed 12 or 72 h after radiation exposure. The gonadosomatic index (GSI) was calculated. Blood samples were collected for enzyme-linked immunosorbent assay (ELISA). Ovaries were harvested for histological examination, immunohistochemistry, immunofluorescence, TUNEL, western blot, and qPCR. The fertility assessment was evaluated by calculating live offspring number.

RESULTS

The optimum dose of HKL against radiation was 10 mg/kg via intraperitoneal injection. POF was induced 72 h after irradiation with significantly downregulated proliferating cell nuclear antigen (PCNA). The numbers of primordial and preantral follicles decreased significantly after irradiation (p < .001), whereas the number of atretic follicles increased (p < .001). The serum levels of estradiol (E2 ) and anti-Müllerian hormone (AMH) decreased to 50% of the control group after irradiation (p < .05). Moreover, the GSI after irradiation was 27% lower than in the control group (p < .05). The number of offspring in the IR group dropped by 50% compared with the control group (p < .05). HKL pretreatment protected the animals' fertility, GSI, PCNA, serum levels of E2 and AMH, and the number of primordial and preantral follicles. Significant upregulation of apoptosis-related proteins such as Pho-P53, Bax, Cyto C, C-caspase-3, C-PARP, and pyroptosis-related proteins such as Pho-NF-κB p65, NLRP3, caspase-1, IL-1β, and IL-18 was observed after irradiation, while the expression of Bcl-2 decreased. HKL pretreatment prevented these changes. After irradiation, malondialdehyde (MDA), Nrf2, and HO-1 were upregulated. HKL treatment activated the expression of Nrf2 and HO-1 and promoted the nucleus translocation of Nrf2. Furthermore, HKL did not affect ovarian reserves under physiological conditions.

CONCLUSIONS

HKL ameliorated IR-induced POF by inhibiting apoptosis and pyroptosis by enhancing Nrf2 expression and translocation.

Pharmacological features, health benefits and clinical implications of honokiol

Honokiol (HNK) is a natural polyphenolic compound extracted from the bark and leaves of Magnolia grandiflora. It has been traditionally used as a medicinal compound to treat inflammatory diseases. HNK possesses numerous health benefits with a minimal level of toxicity. It can cross the blood-brain barrier and blood-cerebrospinal fluid, thus having significant bioavailability in the neurological tissues. HNK is a promising bioactive compound possesses neuroprotective, antimicrobial, anti-tumorigenic, anti-spasmodic, antidepressant, analgesic, and antithrombotic features . HNK can prevent the growth of several cancer types and haematological malignancies. Recent studies suggested its role in COVID-19 therapy. It binds effectively with several molecular targets, including apoptotic factors, chemokines, transcription factors, cell surface adhesion molecules, and kinases. HNK has excellent pharmacological features and a wide range of chemotherapeutic effects, and thus, researchers have increased interest in improving the therapeutic implications of HNK to the clinic as a novel agent. This review focused on the therapeutic implications of HNK, highlighting clinical and pharmacological features and the underlying mechanism of action.Communicated by Ramaswamy H. Sarma.

Honokiol decreases alpha-synuclein mRNA levels and reveals novel targets for modulating alpha-synuclein expression

Background

Intracytoplasmic inclusions comprised of aggregated alpha-synuclein (αsyn) represent a key histopathological feature of neurological disorders collectively termed "synucleinopathies," which includes Parkinson's disease (PD). Mutations and multiplications in the SNCA gene encoding αsyn cause familial forms of PD and a large body of evidence indicate a correlation between αsyn accumulation and disease. Decreasing αsyn expression is recognized as a valid target for PD therapeutics, with down-regulation of SNCA expression potentially attenuating downstream cascades of pathologic events. Here, we evaluated if Honokiol (HKL), a polyphenolic compound derived from magnolia tree bark with demonstrated neuroprotective properties, can modulate αsyn levels in multiple experimental models.

Methods

Human neuroglioma cells stably overexpressing αsyn, mouse primary neurons, and human iPSC-derived neurons were exposed to HKL and αsyn protein and SNCA messenger RNA levels were assessed. The effect of HKL on rotenone-induced overexpression of αsyn levels was further assessed and transcriptional profiling of mouse cortical neurons treated with HKL was performed to identify potential targets of HKL.

Results

We demonstrate that HKL can successfully reduce αsyn protein levels and SNCA expression in multiple in vitro models of PD with our data supporting a mechanism whereby HKL acts by post-transcriptional modulation of SNCA rather than modulating αsyn protein degradation. Transcriptional profiling of mouse cortical neurons treated with HKL identifies several differentially expressed genes (DEG) as potential targets to modulate SNCA expression.

Conclusion

This study supports a HKL-mediated downregulation of SNCA as a viable strategy to modify disease progression in PD and other synucleinopathies. HKL has potential as a powerful tool for investigating SNCA gene modulation and its downstream effects.

Intralesional Chemotherapy for Prostate Cancer: In vivo Proof of Principle

INTRODUCTION

Prostate cancer (PCA) is one of the most common cancers in the world, and current therapies are debilitating to patients. To develop a novel modality for the treatment of PCA, we evaluated the efficacy of intralesional administration of the Sirt3 activator Honokiol (HK) and the NADPH oxidase inhibitor Dibenzolium (DIB).

METHODS

We used a well-established transgenic adenocarcinoma mouse prostate (TRAMP-C2) model of hormone-independent PCA. MTS assay, apoptosis assay, wound healing assay, transwell invasion assay, RT-qPCR, and Western blotting were conducted in vitro, and HK and DIB were intratumorally administered to mice bearing TRAMP-C2 tumors. Tumor size and weight were observed over time. After removing tumors, H-E staining and immunohistochemistry (IHC) staining were conducted.

RESULTS

Treatment by HK or DIB showed an inhibitory effect on cell proliferation and migration in PCA cells. Poor ability to induce apoptosis in vitro, insufficient expression of caspase-3 on IHC staining, and increased necrotic areas on H-E staining indicated that necrosis plays an important role in cell death in treating groups by HK or DIB. RT-PCR, Western blotting, and IHC staining for epithelial mesenchymal transition (EMT) markers suggested that EMT was suppressed by HK and DIB individually. In addition, HK induced activation of CD3. Mouse experiments showed safe antitumor effects in vivo.

CONCLUSIONS

HK and DIB suppressed PCA proliferation and migration. Further research will explore the effects of HK and DIB at the molecular level to reveal new mechanisms that can be exploited as therapeutic modalities.

Autophagy and Breast Cancer: Connected in Growth, Progression, and Therapy

Despite an increase in the incidence of breast cancer worldwide, overall prognosis has been consistently improving owing to the development of multiple targeted therapies and novel combination regimens including endocrine therapies, aromatase inhibitors, Her2-targeted therapies, and cdk4/6 inhibitors. Immunotherapy is also being actively examined for some breast cancer subtypes. This overall positive outlook is marred by the development of resistance or reduced efficacy of the drug combinations, but the underlying mechanisms are somewhat unclear. It is interesting to note that cancer cells quickly adapt and evade most therapies by activating autophagy, a catabolic process designed to recycle damaged cellular components and provide energy. In this review, we discuss the role of autophagy and autophagy-associated proteins in breast cancer growth, drug sensitivity, tumor dormancy, stemness, and recurrence. We further explore how autophagy intersects and reduces the efficacy of endocrine therapies, targeted therapies, radiotherapy, chemotherapies as well as immunotherapy via modulating various intermediate proteins, miRs, and lncRNAs. Lastly, the potential application of autophagy inhibitors and bioactive molecules to improve the anticancer effects of drugs by circumventing the cytoprotective autophagy is discussed.

Identification of potential target genes of honokiol in overcoming breast cancer resistance to tamoxifen

Background

Honokiol (HON) inhibits epidermal growth factor receptor (EGFR) signaling and increases the activity of erlotinib, an EGFR inhibitor, in human head and neck cancers. In this study, using a bioinformatics approach and in vitro experiments, we assessed the target genes of HON against breast cancer resistance to tamoxifen (TAM).

Materials and methods

Microarray data were obtained from GSE67916 and GSE85871 datasets to identify differentially expressed genes (DEGs). DEGs common between HON-treated and TAM-resistant cells were analyzed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses and protein-protein interaction (PPI) networks were constructed. Selected genes were analyzed for genetic alterations, expression, prognostic value, and receiver operating characteristics (ROC). TAM-resistant MCF-7 (MCF-7 TAM-R) cells were generated and characterized for their resistance toward TAM. A combination of HON and TAM was used for cytotoxicity and gene expression analyses. Molecular docking was performed using the Molecular Operating Environment software.

Results

PPI network analysis revealed that FN1, FGFR2, and RET were the top three genes with the highest scores. A genetic alteration study of potential target genes revealed MMP16 and ERBB4 as the genes with the highest alterations among the breast cancer samples. Pathway enrichment analysis of FGFR2, RET, ERBB4, SOX2, FN1, and MMP16 showed that the genetic alterations herein were likely to impact the RTK-Ras pathway. The expression levels of RET, MMP16, and SOX2 were strongly correlated with prognostic power, with areas under the ROC curves (AUC) ​​of 1, 0.8, and 0.8, respectively. The HON and TAM combination increased TAM cytotoxicity in MCF-7 TAM-R cells by regulating the expression of potential target genes ret, ERBB4, SOX2, and FN1, as well as the TAM resistance regulatory genes including HES1, VIM, PCNA, TP53, and CASP7. Molecular docking results indicated that HON tended to bind RET, ErbB4, and the receptor protein Notch1 ankyrin domain more robustly than its native ligand.

Conclusion

HON could overcome breast cancer resistance to TAM, potentially by targeting FGFR2, RET, ERBB4, MMP16, FN1, and SOX2. However, further studies are required to validate these results.

Sequential Delivery of Novel Triple Drug Combination via Crosslinked Alginate/Lactoferrin Nanohybrids for Enhanced Breast Cancer Treatment

While breast cancer remains a global health concern, the elaboration of rationally designed drug combinations coupled with advanced biocompatible delivery systems offers new promising treatment venues. Herein, we repurposed rosuvastatin (RST) based on its selective tumor apoptotic effect and combined it with the antimetabolite pemetrexed (PMT) and the tumor-sensitizing polyphenol honokiol (HK). This synergistic three-drug combination was incorporated into protein polysaccharide nanohybrids fabricated by utilizing sodium alginate (ALG) and lactoferrin (LF), inspired by the stealth property of the former and the cancer cell targeting capability of the latter. ALG was conjugated to PMT and then coupled with LF which was conjugated to RST, forming core shell nanohybrids into which HK was physically loaded, followed by cross linking using genipin. The crosslinked HK-loaded PMT-ALG/LF-RST nanohybrids exhibited a fair drug loading of 7.86, 5.24 and 6.11% for RST, PMT and HK, respectively. It demonstrated an eight-fold decrease in the IC50 compared to the free drug combination, in addition to showing an enhanced cellular uptake by MCF-7 cells. The in vivo antitumor efficacy in a breast cancer-bearing mouse model confirmed the superiority of the triple cocktail-loaded nanohybrids. Conclusively, our rationally designed triple drug-loaded protein/polysaccharide nanohybrids offer a promising, biocompatible approach for an effective breast tumor suppression.

Comprehensive Computational Analysis of Honokiol Targets for Cell Cycle Inhibition and Immunotherapy in Metastatic Breast Cancer Stem Cells

Breast cancer stem cells (BCSCs) play a critical role in chemoresistance, metastasis, and poor prognosis of breast cancer. BCSCs are mostly dormant, and therefore, activating them and modulating the cell cycle are important for successful therapy against BCSCs. The tumor microenvironment (TME) promotes BCSC survival and cancer progression, and targeting the TME can aid in successful immunotherapy. Honokiol (HNK), a bioactive polyphenol isolated from the bark and seed pods of Magnolia spp., is known to exert anticancer effects, such as inducing cell cycle arrest, inhibiting metastasis, and overcoming immunotherapy resistance in breast cancer cells. However, the molecular mechanisms of action of HNK in BCSCs, as well as its effects on the cell cycle, remain unclear. This study aimed to explore the potential targets and molecular mechanisms of HNK on metastatic BCSC (mBCSC)-cell cycle arrest and the impact of the TME. Using bioinformatics analyses, we predicted HNK protein targets from several databases and retrieved the genes differentially expressed in mBCSCs from the GEO database. The intersection between the differentially expressed genes (DEGs) and the HNK-targets was determined using a Venn diagram, and the results were analyzed using a protein-protein interaction network, hub gene selection, gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, genetic alteration analysis, survival rate, and immune cell infiltration levels. Finally, the interaction between HNK and two HNK-targets regulating the cell cycle was analyzed using molecular docking analysis. The identified potential therapeutic targets of HNK (PTTH) included CCND1, SIRT2, AURKB, VEGFA, HDAC1, CASP9, HSP90AA1, and HSP90AB1, which can potentially inhibit the cell cycle of mBCSCs. Moreover, our results showed that PTTH could modulate the PI3K/Akt/mTOR and HIF1/NFkB/pathways. Overall, these findings highlight the potential of HNK as an immunotherapeutic agent for mBCSCs by modulating the tumor immune environment.

Honokiol Induces Ferroptosis by Upregulating HMOX1 in Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is one of the malignant hematological cancers with high mortality. Finding a more effective and readily available treatment is of the utmost importance. Here, we aimed to identify the anti-leukemia effect of a natural small molecule compound honokiol on a panel of AML cell lines, including THP-1, U-937, and SKM-1, and explored honokiol’s potential biological pathways and mechanisms. The results showed that honokiol decreased the viability of the targeted AML cells, induced their cell cycle arrest at G0/G1 phase, and inhibited their colony-formation capacity. Honokiol also triggers a noncanonical ferroptosis pathway in THP-1 and U-937 cells by upregulating the level of intracellular lipid peroxide and HMOX1 significantly. Subsequent studies verified that HMOX1 was a critical target in honokiol-induced ferroptosis. These results reveal that honokiol is an effective anti-leukemia agent in AML cell lines and may be a potential ferroptosis activator in AML.

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.

Genetic Interpretation of the Impacts of Honokiol and EGCG on Apoptotic and Self-Renewal Pathways in HEp-2 Human Laryngeal CD44high Cancer Stem Cells

Most current larynx cancer therapies are generally aimed at the global mass of tumor, targeting the non-tumorigenic cells, and unfortunately sparing the tumorigenic cancer stem cells (CSCs) that are responsible for sustained growth, metastasis, and chemo- and radioresistance. Phytochemicals and herbs have recently been introduced as therapeutic sources for eliminating CSCs. Therefore, we assessed the anti-tumor effects of two herbal ingredients, the green tea extract "Epigallocatechin-3-gallate (EGCG)" and Honokiol (HNK), on parental cells or CD44^high CSCs of the human laryngeal squamous cell carcinoma cell line HEp-2. Results revealed that EGCG had a preeminent apoptotic potential on HEp-2 laryngeal CSCs. HNK conferred higher cytotoxic impacts on parental cells mostly by necrosis induction, especially with higher doses, but apoptosis induction with lower doses was also observed. The Notch signaling pathway genes were more potently suppressed by EGCG than HNK. However, HNK surpassed EGCG in downregulating the β-catenin and the Sonic Hedgehog signaling pathways genes. On a genetic basis, both agents engaged the BCL-2 family-regulated and caspase-dependent intrinsic apoptotic pathway, but EGCG and HNK triggered apoptosis via p53-independent and p53-dependent pathways, respectively. Taken together, EGCG and HNK eradicated HEp-2 human larynx cancer cells through targeting multiple self-renewal pathways and activating diverse cell death modalities.

Novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives suppress cancer via inducing PI3K/Akt/mTOR-dependent autophagy

Honokiol is a bioactive biphenolic component derived from Magnoliae officinalis Cortex (known as "Hou Po" in Chinese), a traditional Chinese herbal medicine. A series of novel 1,3,4-thiadiazole/oxadiazole-linked honokiol derivatives were synthesized and tested for anticancer activity against seven human cancer cell lines in this study. Among all derivatives, 8a had the most potent cytotoxic effect on all tested cancer cells, with IC₅₀ values ranging from 1.62 ± 0.19 to 4.61 ± 0.51 µM, which were 10.38-34.36 folds more potent than the parental honokiol (IC₅₀ values of 30.96 ± 1.81-55.67 ± 0.31 µM). On A549, HCT116, and MDA-MB-231 cell lines, 8a demonstrated 5.69-fold, 5.65-fold, and 4.83-fold greater cytotoxicity than cisplatin, respectively. Compound 8a also had higher selectivity (SI values of 8.41-49.38) towards seven cancer cell lines over the normal cell lines than cisplatin (SI values of 1.24-2.52). The analysis of structure-activity relationships (SARs) revealed that honokiol derivatives bearing 1,3,4-thiadiazoles (8a-j) possessed stronger anticancer activity than those containing 1,3,4-oxadiazoles. Further mechanistic investigation indicated that 8a induced cytotoxic autophagy in cancer cells in a time- and dose-independent manner via suppressing the PI3K/Akt/mTOR pathway. Molecular docking suggested that 8a could bind to the PI3Kα active sites. Additionally, 8a inhibited the migration and invasion of A549 and MDA-MB-231 cancer cells.

Honokiol: A naturally occurring lignan with pleiotropic bioactivities

Honokiol is the dominant biphenolic compound isolated from the Magnolia tree, and has long been considered as the active constituent of the traditional Chinese herb, 'Houpo', which is widely used to treat symptoms due to 'stagnation of qi'. Pharmacological studies have shown that honokiol possesses a wide range of bioactivities without obvious toxicity. Honokiol protects the liver, kidneys, nervous system, and cardiovascular system through reducing oxidative stress and relieving inflammation. Moreover, honokiol shows anti-diabetic property through enhancing insulin sensitivity, and anti-obese property through promoting browning of adipocytes. In vivo and in vitro studies indicated that honokiol functions as an anti-cancer agent through multiple mechanisms: inhibiting angiogenesis, promoting cell apoptosis, and regulating cell cycle. A variety of therapeutic effects of honokiol may be associated with its physiochemical properties, which make honokiol readily cross the blood brain barrier and the blood-cerebrospinal fluid barrier, with high bioavailability. In the future, more clinical researches on honokiol are needed to fully authenticate its therapeutic values.

Natural Lignans Honokiol and Magnolol as Potential Anticarcinogenic and Anticancer Agents. A Comprehensive Mechanistic Review

Plant lignans constitute an important group of polyphenols, which have been demonstrated to significantly induce cancer cell death and suppress cancer cell proliferation with minimal toxicity against non-transformed cells. Numerous epidemiological studies have shown that the intake of lignans is associated with lower risk of several cancers. These natural compounds have the potential to inhibit carcinogenesis, tumor growth, and metastasis by targeting various signaling molecules and pathways. Growing evidence indicates that honokiol and magnolol as natural lignans possess potent anticancer activities against various types of human cancer. The aim of present review is to provide the reader with the newest findings in understanding the cellular and molecular mechanisms mediating anticancer effects of honokiol and magnolol. This review comprehensively elucidates the effects of honokiol and magnolol on the molecular targets and signal transduction pathways implicated in cancer cell proliferation and metastasis. The findings of current review indicate that honokiol and magnolol can be considered as promising carcinopreventive and anticancer agents.

Honokiol inhibits hepatoma carcinoma cell migration through downregulated Cyclophilin B expression

Hepatocellular carcinoma (HCC) is the fifth common types of cancer with poor prognosis in the world. Honokiol (HNK), a natural biphenyl compound derived from the magnolia plant, has been reported to exert anticancer effects, but its mechanism has not been elucidated exactly. In the present study, HNK treatment significantly suppressed the migration ability of HepG2 and Hep3B human hepatocellular carcinoma. The treatment reduced the expression levels of the genes associated with cell migration, such as S100A4, MMP-2, MMP-9 and Vimentin. Interestingly, treatment with HNK significantly reduced the expression level of Cyclophilin B (CypB) which stimulates cancer cell migration. However, overexpressed CypB abolished HNK-mediated suppression of cell migration, and reversed the apoptotic effects of HNK. Altogether, we concluded that the suppression of migration activities by HNK was through down-regulated CypB in HCC. These finding suggest that HNK may be a promising candidate for HCC treatment via regulation of CypB.

A novel 'smart' PNIPAM-based copolymer for breast cancer targeted therapy: Synthesis, and characterization of dual pH/temperature-responsive lactoferrin-targeted PNIPAM-co-AA

Despite the active research towards introducing novel anticancer agents, the long-term sequelae and side effects of chemotherapy remain the major obstacle to achieving clinical success. Recent cancer research is now utilizing the medicinal chemistry toolbox to tailor novel 'smart' carrier systems that can reduce the major limitations of chemotherapy ranging from non-specificity and ubiquitous biodistribution to systemic toxicity. In this aspect, various stimuli-responsive polymers have gained considerable interest due to their intrinsic tumor targeting properties. Among these polymers, poly(N-isopropylacrylamide (PNIPAM) has been chemically modified to tune its thermoresponsivity or even copolymerized to endow new stimulus responsiveness for enhancing tumor targeting. Herein, we set our design rationale to impart additional active targeting entity to pH/temperature-responsive PNIPAM-based polymer for more efficient controlled payloads accumulation at the tumor through cellular internalization via synthesizing novel "super intelligent" lactoferrin conjugated PNIPAM-acrylic acid (LF-PNIPAM-co-AA) copolymer. The synthesized copolymer was physicochemically characterized and evaluated as a smart nanocarrier for targeting breast cancer. In this regard, Honokiol (HK) was utilized as a model anticancer drug and encapsulated in the nanoparticles to overcome its lipophilic nature and allow its parenteral administration, for achieving sustainable drug release with targeting action. Results showed that the developed HK-loaded LF-PNIPAM-co-AA nanohydrogels displayed high drug loading capacity reaching to 18.65 wt.% with excellent physical and serum stability. Moreover, the prepared HK-loaded nanohydrogels exhibited efficient in vitro and in vivo antitumor activities. In vivo, HK-loaded nanohydrogels demonstrated suppression of VEGF-1 and Ki-67 expression levels, besides inducing apoptosis through upregulating the expression level of active caspase-3 in breast cancer-bearing mice. Overall, the developed nanohydrogels (NGs) with pH and temperature responsivity provide a promising nanocarrier for anticancer treatment.

Induction of STK11-dependent cytoprotective autophagy in breast cancer cells upon honokiol treatment

Cancer cells hijack autophagy pathway to evade anti-cancer therapeutics. Many molecular signaling pathways associated with drug-resistance converge on autophagy induction. Honokiol (HNK), a natural phenolic compound purified from Magnolia grandiflora, has recently been shown to impede breast tumorigenesis and, in the present study, we investigated whether breast cancer cells evoke autophagy to modulate therapeutic efficacy and functional networks of HNK. Indeed, breast cancer cells exhibit increased autophagosomes-accumulation, MAP1LC3B-II/LC3B-II-conversion, expression of ATG proteins as well as elevated fusion of autophagosomes and lysosomes upon HNK treatment. Breast cancer cells treated with HNK demonstrate significant growth inhibition and apoptotic induction, and these biological processes are blunted by macroautophagy/autophagy. Consequently, inhibiting autophagosome formation, abrogating autophagosome-lysosome fusion or genetic-knockout of BECN1 and ATG7 effectively increase HNK-mediated apoptotic induction and growth inhibition. Next, we explored the functional impact of tumor suppressor STK11 in autophagy induction in HNK-treated cells. STK11-silencing abrogates LC3B-II-conversion, and blocks autophagosome/lysosome fusion and lysosomal activity as illustrated by LC3B-Rab7 co-staining and DQ-BSA assay. Our results exemplify the cytoprotective nature of autophagy invoked in HNK-treated breast cancer cells and put forth the notion that a combined strategy of autophagy inhibition with HNK would be more effective. Indeed, HNK and chloroquine (CQ) show synergistic inhibition of breast cancer cells and HNK-CQ combination treatment effectively inhibits breast tumorigenesis and metastatic progression. Tumor-dissociated cells from HNK-CQ treated tumors exhibit abrogated invasion and migration potential. Together, these results implicate that breast cancer cells undergo cytoprotective autophagy to circumvent HNK and a combined treatment with HNK and CQ can be a promising therapeutic strategy for breast cancer.

Anti‑proliferative effect of honokiol on SW620 cells through upregulating BMP7 expression via the TGF‑β1/p53 signaling pathway

Honokiol (HNK), a natural pharmaceutically active component extracted from magnolia bark, has been used for clinical treatments and has anti‑inflammatory, antiviral and antioxidative effects. In recent years, anticancer research has become a major hotspot. However, the underlying molecular mechanisms of how HNK inhibits colorectal cancer have remained elusive. The present study focused on elucidating the effects of HNK on the expression of bone morphogenetic protein (BMP)7 and its downstream interaction with transforming growth factor (TGF)‑β1 and p53 in colon cancer. In in vitro assays, cell viability, cell cycle distribution and apoptosis were examined using Cell Counting Kit‑8, flow cytometry and reverse transcription‑quantitative PCR, respectively. In addition, the expression of BMP7, TGF‑β1 and relevant signaling proteins was determined by western blot analysis. In vivo, the anticancer effect of HNK was assessed in xenografts in nude mice. Furthermore, immunohistochemistry was performed to evaluate the association between BMP7 and TGF‑β1 expression in colon cancer. The results indicated that HNK inhibited the proliferation of colon cancer cell lines, with SW620 cells being more sensitive than other colon cancer cell lines. Furthermore, HNK markedly promoted the expression of BMP7 at the mRNA and protein level. Exogenous BMP7 potentiated the effect of HNK on SW620 cells, while knocking down BMP7 inhibited it. As a downstream mechanism, HNK increased the expression of TGF‑β1 and p53, which was enhanced by exogenous BMP7 in SW620 cells. In addition, immunohistochemical analysis indicated a positive association between BMP7 and TGF‑β1 expression. Hence, the present results suggested that HNK is a promising agent for the treatment of colon cancer and enhanced the expression TGF‑β1 and p53 through stimulating BMP7 activity via the non‑canonical TGF‑β signaling pathway.

Natural tyrosine kinase inhibitors acting on the epidermal growth factor receptor: Their relevance for cancer therapy

Epidermal growth factor receptor (EGFR), also known as ErbB-1/HER-1, plays a key role in the regulation of the cell proliferation, migration, differentiation, and survival. Since the constitutive activation or overexpression of EGFR is nearly found in various cancers, the applications focused on EGFR are the most widely used in the clinical level, including the therapeutic drugs of targeting EGFR, monoclonal antibodies (mAbs) and tyrosine kinase inhibitors (TKIs).Over the past decades, the compounds from natural sources have been a productive source of novel drugs, especially in both discovery and development of anti-tumor drugs by targeting the EGFR pathways as the TKIs. This work presents a review of the compounds from natural sources as potential EGFR-TKIs involved in the regulation of cancer. Moreover, high-throughput drug screening of EGFR-TKIs from the natural compounds has also been summarized.

Recent Advances in Designing 5-Fluorouracil Delivery Systems: A Stepping Stone in the Safe Treatment of Colorectal Cancer

5-Fluorouracil (5-FU) has become one of the most widely employed antimetabolite chemotherapeutic agents in recent decades. It is considered a first line antineoplastic agent for the treatment of colorectal cancer. Unfortunately, chemotherapy with 5-FU has several limitations, including its short half-life, high cytotoxicity and low bioavailability. In order to overcome the drawbacks of 5-FU and enhance its therapeutic efficiency, many scientific groups have focused on designing a new delivery system to successfully deliver 5-FU to tumor sites. We provide a comprehensive review on different strategies to design effective delivery systems, including nanoformulations, drug-conjugate formulations and other strategies for the delivery of 5-FU to colorectal cancer. Furthermore, co-delivery of 5-FU with other therapeutics is discussed. This review critically highlights the recent innovations in and literature on various types of carrier system for 5-FU.

Role of natural compounds in preventing and treating breast cancer

Breast cancer (BrCa) is the most commonly diagnosed cancer and the second leading cause of cancer-related death in women. Alarming increases in the cases quests for more effective treatment of BrCa. As most chemotherapeutic drugs are associated with drug resistance, cancer relapse, and side effects, scientists are turning to agents with more efficacy, such as natural compounds for treatment and prevention of BrCa. Selected natural compounds, substances derived from living organisms, promote apoptosis and inhibit metastasis, preventing cancer growth. As a result, these compounds have the potential to suppress BrCa progression, thus increasing patient survival rates and decreasing the number of BrCa-related deaths. In this review, we summarize natural compounds that have displayed, anti-cancer effects on BrCa cells in various studies. These natural compounds inhibit the development of BrCa, suppress the growth of cancer cells, and promote cell death. We conclude that natural compounds are efficient, effective and promising agents for treating BrCa other than therapeutic methods.

Intraperitoneal administration of biocompatible hyaluronic acid hydrogel containing multi-chemotherapeutic agents for treatment of colorectal peritoneal carcinomatosis

Colorectal peritoneal carcinomatosis (CRPC) is an advanced stage of colorectal cancer (CRC), which significantly decreases patient survival and quality of life. Here, the naturally occurring polysaccharide hyaluronic acid (HA) was used to prepare an injectable hydrogel and simultaneously deliver 5-fluorouracil (5-FU), cisplatin (DDP) and paclitaxel (PTX) microspheres for intraperitoneal CRPC chemotherapy. The drug-loaded HA hydrogel released the drugs in a sustained manner, and showed low toxicity both in vitro and in a mouse model of CRPC. Furthermore, direct injection of the drug-loaded HA hydrogel in the abdominal cavity of tumor-bearing mice significantly decreased tumor growth and liver/lung metastasis, along with decreasing the volume of ascites and inhibiting local intestinal infiltration of the tumor cells. Therefore, this novel multi-drug hydrogel delivery system may effectively clear CRPC tumors without any adverse effects when used in intraperitoneal chemotherapy.

Systemic Pharmacological Approach to Identification and Experimental Verification of the Effect of Anisi Stellati Fructus Extract on Chronic Myeloid Leukemia Cells

Anisi stellati fructus (ASF) is the dried fruit of the Illicium verum Hook.f. tree. The aim of this research was to evaluate the antileukemic effect of ASF on chronic myeloid leukemia (CML) cells, which was hypothesized from the systemic pharmacological analysis of ASF, focusing on the combined effect of ASF extract (ASFE) and imatinib (IM). The compounds of ASF were identified using the Traditional Chinese Medicine Systems Pharmacology database and analysis platform. The target gene information was acquired from the UniProt database. The compound and target interaction network was generated from Cytoscape 3.7.1. Using this analysis, 10 compounds effective against CML cells were obtained. ASFE was prepared and analyzed by high-pressure liquid chromatography to provide experimental proof for the relationship between ASF and CML. The anti-p210^Bcr-Abl effects of ASFE and ASFE + IM combination were evaluated by western blotting. Either ASFE alone or in combined treatment with IM on K-562 CML cells resulted in a significant reduction of the Bcr-Abl levels. As expected from the systemic analysis results, ASF had antileukemic activity, showing that it is a potential therapy for CML.

Honokiol: A Review of Its Anticancer Potential and Mechanisms

Cancer is characterised by uncontrolled cell division and abnormal cell growth, which is largely caused by a variety of gene mutations. There are continuous efforts being made to develop effective cancer treatments as resistance to current anticancer drugs has been on the rise. Natural products represent a promising source in the search for anticancer treatments as they possess unique chemical structures and combinations of compounds that may be effective against cancer with a minimal toxicity profile or few side effects compared to standard anticancer therapy. Extensive research on natural products has shown that bioactive natural compounds target multiple cellular processes and pathways involved in cancer progression. In this review, we discuss honokiol, a plant bioactive compound that originates mainly from the Magnolia species. Various studies have proven that honokiol exerts broad-range anticancer activity in vitro and in vivo by regulating numerous signalling pathways. These include induction of G0/G1 and G2/M cell cycle arrest (via the regulation of cyclin-dependent kinase (CDK) and cyclin proteins), epithelial-mesenchymal transition inhibition via the downregulation of mesenchymal markers and upregulation of epithelial markers. Additionally, honokiol possesses the capability to supress cell migration and invasion via the downregulation of several matrix-metalloproteinases (activation of 5' AMP-activated protein kinase (AMPK) and KISS1/KISS1R signalling), inhibiting cell migration, invasion, and metastasis, as well as inducing anti-angiogenesis activity (via the down-regulation of vascular endothelial growth factor (VEGFR) and vascular endothelial growth factor (VEGF)). Combining these studies provides significant insights for the potential of honokiol to be a promising candidate natural compound for chemoprevention and treatment.

Bioactive Compounds: Multi-Targeting Silver Bullets for Preventing and Treating Breast Cancer

Each cell in our body is designed with a self-destructive trigger, and if damaged, can happily sacrifice itself for the sake of the body. This process of self-destruction to safeguard the adjacent normal cells is known as programmed cell death or apoptosis. Cancer cells outsmart normal cells and evade apoptosis and it is one of the major hallmarks of cancer. The cardinal quest for anti-cancer drug discovery (bioactive or synthetic compounds) is to be able to re-induce the so called “programmed cell death” in cancer cells. The importance of bioactive compounds as the linchpin of cancer therapeutics is well known as many effective chemotherapeutic drugs such as vincristine, vinblastine, doxorubicin, etoposide and paclitaxel have natural product origins. The present review discusses various bioactive compounds with known anticancer potential, underlying mechanisms by which they induce cell death and their preclinical/clinical development. Most bioactive compounds can concurrently target multiple signaling pathways that are important for cancer cell survival while sparing normal cells hence they can potentially be the silver bullets for targeting cancer growth and metastatic progression.

Antidepressant-Like Effect and Mechanism of Action of Honokiol on the Mouse Lipopolysaccharide (LPS) Depression Model

There is growing evidence that neuroinflammation is closely linked to depression. Honokiol, a biologically active substance extracted from Magnolia officinalis, which is widely used in traditional Chinese medicine, has been shown to exert significant anti-inflammatory effects and improve depression-like behavior caused by inflammation. However, the specific mechanism of action of this activity is still unclear. In this study, the lipopolysaccharide (LPS) mouse model was used to study the effect of honokiol on depression-like behavior induced by LPS in mice and its potential mechanism. A single administration of LPS (1 mg/kg, intraperitoneal injection) increased the immobility time in the forced swimming test (FST) and tail suspension test (TST), without affecting autonomous activity. Pretreatment with honokiol (10 mg/kg, oral administration) for 11 consecutive days significantly improved the immobility time of depressed mice in the FST and TST experiments. Moreover, honokiol ameliorated LPS-induced NF-κB activation in the hippocampus and significantly reduced the levels of the pro-inflammatory cytokines; tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interferon γ (IFN-γ). In addition, honokiol inhibited LPS-induced indoleamine 2,3-dioxygenase (IDO) activation and quinolinic acid (a toxic product) increase and reduced the level of free calcium in brain tissue, thereby inhibiting calcium overload. In summary, our results indicate that the anti-depressant-like effects of honokiol are mediated by its anti-inflammatory effects. Honokiol may inhibit the LPS-induced neuroinflammatory response through the NF-κB signaling pathway, reducing the levels of related pro-inflammatory cytokines, and furthermore, this may affect tryptophan metabolism and increase neuroprotective metabolites.

Honokiol induces apoptosis and suppresses migration and invasion of ovarian carcinoma cells via AMPK/mTOR signaling pathway

Honokiol, a natural biphenolic compound, exerts anticancer effects through a variety of mechanisms on multiple types of cancer with relatively low toxicity. Adenosine 5'‑phosphate‑activated protein kinase (AMPK), an essential regulator of cellular homeostasis, may control cancer progression. The present study aimed to investigate whether the anticancer activities of honokiol in ovarian cancer cells were mediated through the activation of AMPK. Honokiol decreased cell viability of 2 ovarian cancer cell lines, with an half‑maximal inhibitory concentration value of 48.71±11.31 µM for SKOV3 cells and 46.42±5.37 µM for Caov‑3 cells. Honokiol induced apoptosis via activation of caspase‑3, caspase‑7 and caspase‑9, and cleavage of poly‑(adenosine 5'‑diphosphate‑ribose) polymerase. Apoptosis induced by honokiol was weakened by compound C, an AMPK inhibitor, suggesting that honokiol‑induced apoptosis was dependent on the AMPK/mechanistic target of rapamycin signaling pathway. Additionally, honokiol inhibited the migration and invasion of ovarian cancer cells. The combined treatment of honokiol with compound C reversed the activities of honokiol in wound healing and Matrigel invasion assays. These results indicated that honokiol may have therapeutic potential in ovarian cancer by targeting AMPK activation.

Honokiol induces apoptosis of lung squamous cell carcinoma by targeting FGF2-FGFR1 autocrine loop

Lung squamous cell carcinoma (SCC) accounts for a considerable proportion of lung cancer cases, but there is still a lack of effective therapies. FGFR1 amplification is generally considered a promising therapeutic target. Honokiol is a chemical compound that has been proven to be effective against various malignancies and whose analog has been reported to target the mitogen‐activated protein kinase family, members of a downstream signaling pathway of FGFR1. This was an explorative study to determine the mechanism of honokiol in lung SCC. We found that honokiol induced apoptosis and cell cycle arrest in lung SCC cell lines in a time‐ and dose‐dependent manner. Honokiol also restricted cell migration in lung SCC cell lines. Moreover, the expression of FGF2 and the activation of FGFR1 were both downregulated by honokiol. Pharmacological inhibition and siRNA knockdown of FGFR1 induced apoptosis in lung SCC cells. Our in vivo study indicated that honokiol could suppress the growth of xenograft tumors, and this effect was associated with the inhibition of the FGF2‐FGFR1 signaling pathway. In conclusion, honokiol induced cell apoptosis in lung SCC by targeting the FGF2‐FGFR1 autocrine loop.

Magnolol: A Neolignan from the Magnolia Family for the Prevention and Treatment of Cancer

The past few decades have witnessed widespread research to challenge carcinogenesis; however, it remains one of the most important health concerns with the worst prognosis and diagnosis. Increasing lines of evidence clearly show that the rate of cancer incidence will increase in future and will create global havoc, designating it as an epidemic. Conventional chemotherapeutics and treatment with synthetic disciplines are often associated with adverse side effects and development of chemoresistance. Thus, discovering novel economic and patient friendly drugs that are safe and efficacious is warranted. Several natural compounds have proved their potential against this dreadful disease so far. Magnolol is a hydroxylated biphenyl isolated from the root and stem bark of Magnolia tree. Magnolol can efficiently prevent or inhibit the growth of various cancers originating from different organs such as brain, breast, cervical, colon, liver, lung, prostate, skin, etc. Considering these perspectives, the current review primarily focuses on the fascinating role of magnolol against various types of cancers, and the source and chemistry of magnolol and the molecular mechanism underlying the targets of magnolol are discussed. This review proposes magnolol as a suitable candidate that can be appropriately designed and established into a potent anti-cancer drug.

CD47-ligation induced cell death in T-acute lymphoblastic leukemia

CD47 is a cell-surface marker well recognized for its anti-phagocytic functions. As such, an emerging avenue for targeted cancer therapies involves neutralizing the anti-phagocytic function using monoclonal antibodies (mAbs) to enhance tumour cell immunogenicity. A lesser known consequence of CD47 receptor ligation is the direct induction of tumour cell death. While several mAbs and their derivatives with this property have been studied, the best characterized is the commercially available mAb B6H12, which requires immobilization for induction of cell death. Here, we describe a commercially available mAb, CC2C6, which induces T-cell acute lymphoblastic leukemia (ALL) cell death in soluble form. Soluble CC2C6 induces CD47-dependent cell death in a manner consistent with immobilized B6H12, which is characterized by mitochondrial deficiencies but is independent of caspase activation. Titration studies indicated that CC2C6 shares a common CD47-epitope with B6H12. Importantly, CC2C6 retains the anti-phagocytic neutralizing function, thus possessing dual anti-tumour properties. Although CD47-ligation induced cell death occurs in a caspase-independent manner, CC2C6 was found to stimulate increases in Mcl-1 and NOXA levels, two Bcl-2 family proteins that govern the intrinsic apoptosis pathway. Further analysis revealed that the ratio of Mcl-1:NOXA were minimally altered for cells treated with CC2C6, in comparison to cells treated with agents that induced caspase-dependent apoptosis which alter this ratio in favour of NOXA. Finally, we found that CC2C6 can synergize with low dose chemotherapeutic agents that induce classical apoptosis, giving rise to the possibility of an effective combination treatment with reduced long-term sequelae associated with high-dose chemotherapies in childhood ALL.

Antihyperalgesic Properties of Honokiol in Inflammatory Pain Models by Targeting of NF-κB and Nrf2 Signaling

The present study investigates the possible anti-nociceptive effect of intraperitoneal (i.p.) honokiol: a phenolic compound originally isolated from Magnolia officinalis, in acute and chronic inflammatory pain models. Doses of 0.1, 5, and 10 mg/kg honokiol were administered in carrageenan induced pain and the dose (honokiol 10 mg/kg i.p.) with most significant response among behavioral tests was selected for further experiments. The i.p. administration of honokiol inhibits mechanical hyperalgesia, mechanical allodynia, and thermal hyperalgesia, without causing any apparent toxicity. To elucidate the effect of honokiol on various cytokines and antioxidant enzymes, quantitative real-time-PCR was performed to determine the expression levels of pro-inflammatory cytokines and antioxidant enzymes. It is demonstrated that honokiol significantly reduced the expression levels of tumor necrosis factor (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), and vascular endothelial growth factor (VEGF). Similarly, honokiol was also found to potentiate the expression of nuclear factor erythroid 2-related factor 2 (Nrf2), superoxide dismutase 2 (SOD2), and heme oxygenase-1 (HO-1) levels. Additionally, honokiol significantly reduced plasma nitrite levels as compared to complete Freund's adjuvant (CFA) induced group. X-ray analysis and hematoxylin and eosin (H&E) staining of inflamed and treated paws showed that honokiol reduced the inflammation with significantly less leukocyte infiltration and soft tissue inflammation. In order to explore the possible mechanism of action of honokiol, agonists [piroxicam (5 mg/kg), tramadol (50 mg/kg), and gabapentin (5 mg/kg) i.p.] as well as antagonists [naloxone (4 mg/kg), olanzapine (10 mg/kg), and flumazenil (0.2 mg/kg) i.p.] were used to study involvement of various receptors on the anti-nociceptive effect of honokiol. The potential side effects of honokiol on muscle activity were assessed. An adverse effect testing of honokiol by liver and renal functions were also carried out. The effect of oral honokiol was also assessed on gastrointestinal (GIT) mucosa. Our results demonstrate that honokiol has a significant anti-nociceptive activity through inhibition of anti-inflammatory mediators.

Honokiol inhibits in vitro and in vivo growth of oral squamous cell carcinoma through induction of apoptosis, cell cycle arrest and autophagy

Honokiol, an active natural product derived from Magnolia officinalis, exerted anticancer effects through a variety of mechanisms on multiple types of cancers. In this study, the molecular mechanisms of honokiol in suppressing the human oral squamous cell carcinoma (OSCC) cells were evaluated. Treatment of two OSCC cell lines with honokiol resulted in reducing the cell proliferation and arresting the cell cycle at G1 stage which was correlated with the down‐regulation of Cdk2 and Cdk4 and the up‐regulation of cell cycle suppressors, p21 and p27. In addition, the caspase‐dependent programmed cell death was substantially detected, and the autophagy was induced as the autophagosome formation and autophagic flux proceeded. Modulation of autophagy by autophagic inducer, rapamycin or inhibitors, 3‐MA or bafilomycin, potentiated the honokiol‐mediated anti‐OSCC effects where honokiol exerted multiple actions in suppression of MAPK pathway and regulation of Akt/mTOR or AMPK pathways. As compared to clinical therapeutic agent, 5‐FU, honokiol exhibited more potent activity against OSCC cells and synergistically enhanced the cytotoxic effect of 5‐FU. Furthermore, orally administrated honokiol exerted effective antitumour activity in vivo in OSCC‐xenografted mice. Thus, this study revealed that honokiol could be a promising candidate in preventing human OSCCs.

A mechanistic overview of herbal medicine and botanical compounds to target transcriptional factors in Breast cancer

The abnormalities of transcription factors, such as NF-κB, STAT, estrogen receptor, play a critical role in the initiation and progression of breast cancer. Due to the limitation of current treatment, transcription factors could be promising therapeutic targets, which have received close attention. In this review, we introduced herbal medicines, as well as botanical compounds that had been verified with anti-tumor properties via regulating transcription factors. Herbs, compounds, as well as formulae reported with various transcriptional targets, were summarized thoroughly, to provide implication for the future research on basic experiment and clinical application.

Honokiol-loaded polymeric nanoparticles: an active targeting drug delivery system for the treatment of nasopharyngeal carcinoma

The purpose of this study was to develop a novel drug delivery system for a sustained and targeted delivery of honokiol (HK) to the nasopharyngeal carcinoma (NPC) HNE-1 cell lines, since the folate receptor (FR) is over-expressed on their surface. Emulsion solvent evaporation was used to develop the active targeting nanoparticles-loaded HK (ATNH) using copolymerpoly (ɛ-caprolactone)-poly (ethyleneglycol)-poly (ɛ-caprolactone) (PCEC), which was modified with folate (FA) by introducing Polythylenimine (PEI). ATNH characterization, including particle size distribution, morphology, drug loading, encapsulation efficiency and drug release, was performed. Transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR) were employed to evaluate the shape and construction, respectively. MTT assay, cell uptake study and apoptosis test were assayed to detect the antitumor properties and targeting uptake by HNE-1 cells in vitro. Cell-cycle redistribution, ¹⁸F-FDG PET/CT and immunohistochemistry were performed in vivo. The ATNH we developed were successfully synthesized and showed a suitable size distribution, high encapsulation efficiency, gradual release, and targeting uptake by the cells in vitro. Moreover, ATNH significantly inhibited tumor growth, metabolism, proliferation, micro-vessel generation, and caused cell-cycle arrest at G₁ phase. Thus, these nanoparticles we developed might represent a novel formulation for HK delivery and a promising potential therapy in the treatment of cancer.

Overcoming Resistance to Cetuximab with Honokiol, A Small-Molecule Polyphenol

Overexpression and activation of the EGFR have been linked to poor prognosis in several human cancers. Cetuximab is a mAb against EGFR that is used for the treatment in head and neck squamous cell carcinoma (HNSCC) and metastatic colorectal cancer. Unfortunately, most tumors have intrinsic or will acquire resistance to cetuximab during the course of therapy. Honokiol is a natural compound found in the bark and leaves of the Chinese Magnolia tree and is established to have several anticancer properties without appreciable toxicity. In this study, we hypothesized that combining cetuximab and honokiol treatments could overcome acquired resistance to cetuximab. We previously developed a model of acquired resistance to cetuximab in non-small cell lung cancer H226 cell line. Treatment of cetuximab-resistant clones with honokiol and cetuximab resulted in a robust antiproliferative response. Immunoblot analysis revealed the HER family and their signaling pathways were downregulated after combination treatment, most notably the proliferation (MAPK) and survival (AKT) pathways. In addition, we found a decrease in phosphorylation of DRP1 and reactive oxygen species after combination treatment in cetuximab-resistant clones, which may signify a change in mitochondrial function. Furthermore, we utilized cetuximab-resistant HNSCC patient-derived xenografts (PDX) to test the benefit of combinatorial treatment in vivo There was significant growth delay in PDX tumors after combination treatment with a subsequent downregulation of active MAPK, AKT, and DRP1 signaling as seen in vitro Collectively, these data suggest that honokiol is a promising natural compound in overcoming acquired resistance to cetuximab. Mol Cancer Ther; 17(1); 204-14. ©2017 AACR.

Biological activity and toxicity of the Chinese herb Magnolia officinalis Rehder & E. Wilson (Houpo) and its constituents

Traditional Chinese herbal drugs have been used for thousands of years in Chinese pharmacopoeia. The bark of Magnolia officinalis Rehder & E. Wilson, known under the pinyin name "Houpo", has been traditionally used in Chinese and Japanese medicines for the treatment of anxiety, asthma, depression, gastrointestinal disorders, headache, and more. Moreover, Magnolia bark extract is a major constituent of currently marketed dietary supplements and cosmetic products. Much pharmacological activity has been reported for this herb and its major compounds, notably antioxidant, anti-inflammatory, antibiotic and antispasmodic effects. However, the mechanisms underlying this have not been elucidated and only a very few clinical trials have been published. In vitro and in vivo toxicity studies have also been published and indicate some intriguing features. The present review aims to summarize the literature on M. officinalis bark composition, utilisation, pharmacology, and safety.

Biodegradable polymeric micelles coencapsulating paclitaxel and honokiol: a strategy for breast cancer therapy in vitro and in vivo

The combination of chemotherapy drugs attracts more attention in clinical cancer trials. However, the poor water solubility of chemotherapeutic drugs restricts their anticancer application. In order to improve antitumor efficiency and reduce side effects of free drugs, we prepared paclitaxel (PTX) and honokiol (HK) combination methoxy poly(ethylene glycol)–poly(caprolactone) micelles (P–H/M) by solid dispersion method against breast cancer. The particle size of P–H/M was 28.7±2.5 nm, and transmission electron microscope image confirmed that P–H/M were spherical in shape with small particle size. After being encapsulated in micelles, the release of PTX or HK showed a sustained behavior in vitro. In addition, both the cytotoxicity and the cellular uptake of P–H/M were increased in 4T1 cells, and P–H/M induced more apoptosis than PTX-loaded micelles or HK-loaded micelles, as analyzed by flow cytometry assay and Western blot. Furthermore, the antitumor effect of P–H/M was significantly improved compared with PTX-loaded micelles or HK-loaded micelles in vivo. P–H/M were more effective in inhibiting tumor proliferation, inducing tumor apoptosis, and decreasing the density of microvasculature. Moreover, bioimaging analysis showed that drug-loaded polymeric micelles could accumulate more in tumor tissues compared with the free drug. Our results suggested that P–H/M may have potential applications in breast cancer therapy.

Honokiol nanomicellar formulation produced increased oral bioavailability and anticancer effects in triple negative breast cancer (TNBC)

Triple negative breast cancer (TNBC), owing to its aggressive behavior and toxicity associated with available chemotherapy; currently no suitable therapy is available. Honokiol (HNK) is a promising anticancer drug but has poor bioavailability. In the current study, we evaluated the anticancer effects of an oral Honokiol nanomicellar (NM) formulation (size range of 20-40nm) in vitro against various TNBC cells lines. Cytotoxicity, clonogenic and wound healing assays demonstrated the promising anticancer effects. In vitro Caco-2 permeability studies suggested increased absorption of Honokiol. Compared to HNK-FD, nanomicellar formulations resulted in significant increase in the oral bioavailability. C_max (4.06 and 3.60-fold) and AUC (6.26 and 5.83-fold) were significantly increased in comparison to oral 40 and 80mg/kg free drug respectively. Further, anticancer effects of these formulations were studied in BALB/c nude mice transplanted with orthotopic MDA-MB-231 cell induced xenografts. After 4 weeks of daily administration of HNK-NM formulation, significant reduction in the tumor volumes and weights compared to free drug (p<0.001) treated groups was observed. Surprisingly, in some of the animals (25%), the treatment resulted in complete eradication of tumors. Increased apoptosis and antiangiogenic effect was observed in HNK-NM groups compared to free drug and untreated control animals. This is the first report demonstrating that HNK-FD possesses anticancer effects against TNBC.

Antineoplastic Effects of Honokiol on Melanoma

Honokiol, a plant lignan has been shown to have antineoplastic effects against nonmelanoma skin cancer developments in mice. In this study, antineoplastic effects of honokiol were investigated in malignant melanoma models. In vitro effects of honokiol treatment on SKMEL-2 and UACC-62 melanoma cells were evaluated by measuring the cell viability, proliferation, apoptosis, cell cycle analysis, and expressions of various proteins associated with cell cycle progression and apoptosis. For the in vivo study, male nude mice inoculated with SKMEL-2 or UACC-62 cells received injections of sesame oil or honokiol for two to seven weeks. In vitro honokiol treatment caused significant decrease in cell viability, proliferation, cell cycle arrest, increased apoptosis, and modulation of apoptotic and cell cycle regulatory proteins. Honokiol caused an accumulation of cells in the G2/M phase of the cell cycle in SKMEL-2 and G0/G1 phase in UACC-62 cells. An elevated level of caspases and PARP were observed in both cell lines treated with honokiol. A decrease in the expression of various cell cycle regulatory proteins was also observed in honokiol treated cells. Honokiol caused a significant reduction of tumor growth in SKMEL-2 and UACC-62 melanoma xenografts. These findings suggest that honokiol is a good candidate for further studies as a possible treatment for malignant melanoma.

Use of 5-Fluorouracil Loaded Micelles and Cisplatin in Thermosensitive Chitosan Hydrogel as an Efficient Therapy against Colorectal Peritoneal Carcinomatosis

Colorectal peritoneal carcinomatosis (CRPC) is a common systemic metastasis of intra-abdominal cancers. Intraperitoneal chemotherapy against CRPC is at present the preferred treatment. The aim of this study is to develop a novel hydrogel drug delivery system through the combination of 5-fluorouracil (5-FU) loaded polymeric micelles and cisplatin (DDP) in biodegradable thermosensitive chitosan (CS) hydrogel. The prepared CS hydrogel drug is a free-flowing solution at room temperature and forms a stationary gel at body temperature. Therefore, a CRPC mouse model is established to investigate the antitumor activity of CS hydrogel drug system. The results suggest that intraperitoneal administration of CS hydrogel drug can inhibit tumor growth and metastasis, and prolong survival time compared with other groups, thus improving the chemotherapeutic effect. Ki-67 immunohistochemical analysis reveals that tumors in the CS hydrogel drug group has lower cell proliferation in contrast to other groups (P < 0.001). Furthermore, hematoxylin-eosin staining of liver and lung tissue indicates that the CS hydrogel drug has also a certain inhibitory effect on colorectal cancer metastasis to the liver and lung. Hence, the work highlights the potential clinical applications of the CS hydrogel drug.