Reversal of multidrug resistance by icaritin in doxorubicin-resistant human osteosarcoma cells

Research Progress of Nanomaterials in Chemotherapy of Osteosarcoma

Osteosarcoma (OS) is a common malignant bone tumor that occurs mostly in children and adolescents. At present, surgery after chemotherapy or postoperative adjuvant chemotherapy is the main treatment plan. However, the efficacy of chemotherapeutic drugs is limited by the occurrence of chemotherapeutic resistance, toxicity to normal cells, poor pharmacokinetic performance, and drug delivery failure. The delivery of chemotherapy drugs to the bone to treat OS may fail for a variety of reasons, such as a lack of selectivity for OS cells, initial sudden release, short-term release, and the presence of biological barriers (such as the blood-bone marrow barrier). Nanomaterials are new materials with at least one dimension on the nanometer scale (1-100 nm) in three-dimensional space. These materials have the ability to penetrate biological barriers and can accumulate preferentially in tumor cells. Studies have shown that the effective combination of nanomaterials and traditional chemotherapy can significantly improve the therapeutic effect. Therefore, this article reviews the latest research progress on the use of nanomaterials in OS chemotherapy.

Icariin as a potential anticancer agent: a review of its biological effects on various cancers

Numerous chemical compounds used in cancer treatment have been isolated from natural herbs to address the ever-increasing cancer incidence worldwide. Therein is icariin, which has been extensively studied for its therapeutic potential due to its anti-inflammatory, antioxidant, antidepressant, and aphrodisiac properties. However, there is a lack of comprehensive and detailed review of studies on icariin in cancer treatment. Given this, this study reviews and examines the relevant literature on the chemopreventive and therapeutic potentials of icariin in cancer treatment and describes its mechanism of action. The review shows that icariin has the property of inhibiting cancer progression and reversing drug resistance. Therefore, icariin may be a valuable potential agent for the prevention and treatment of various cancers due to its natural origin, safety, and low cost compared to conventional anticancer drugs, while further research on this natural agent is needed.

Research Progress of Natural Small-Molecule Compounds Related to Tumor Differentiation

Tumor differentiation is a therapeutic strategy aimed at reactivating the endogenous differentiation program of cancer cells and inducing cancer cells to mature and differentiate into other types of cells. It has been found that a variety of natural small-molecule drugs can induce tumor cell differentiation both in vitro and in vivo. Relevant molecules involved in the differentiation process may be potential therapeutic targets for tumor cells. Compared with synthetic drugs, natural small-molecule antitumor compounds have the characteristics of wide sources, structural diversity and low toxicity. In addition, natural drugs with structural modification and transformation have relatively concentrated targets and enhanced efficacy. Therefore, using natural small-molecule compounds to induce malignant cell differentiation represents a more targeted and potential low-toxicity means of tumor treatment. In this review, we focus on natural small-molecule compounds that induce differentiation of myeloid leukemia cells, osteoblasts and other malignant cells into functional cells by regulating signaling pathways and the expression of specific genes. We provide a reference for the subsequent development of natural small molecules for antitumor applications and promote the development of differentiation therapy.

Icaritin Inhibits Migration and Invasion of Human Ovarian Cancer Cells via the Akt/mTOR Signaling Pathway

Ovarian cancer (OC) is the most lethal of all gynecologic malignancies with poor survival rates. Although surgical treatment and chemotherapy had advanced to improve survival, platinum-based chemoresistance remains a major hurdle in the clinical treatment of OC. The search for novel active ingredients for the treatment of drug-resistant OC is urgently needed. Here, we demonstrated that icaritin, the main active ingredient derived from the traditional Chinese herb Epimedium genus, significantly suppressed the proliferation, migration, and invasion of both drug-susceptible and cisplatin-resistant OC cells in vitro. Mechanistically, icaritin at 20 μM significantly inhibited the phosphorylation of Akt and mTOR, as well as decreased the expression of vimentin and increased the expression of E-cadherin. Our data indicate that icaritin, a prenylated flavonoid natural product, could serve as a potential inhibitor of cisplatin-resistant OC by inhibiting the Akt/mTOR signaling pathway.

Poncirin downregulates ATP-binding cassette transporters to enhance cisplatin sensitivity in cisplatin-resistant osteosarcoma cells

Poncirin, a flavanone glycoside with bitter taste extracted from dried immature fruit of Poncirus trifoliate, exhibits multiple biological activities including anti-tumor activity. Our study aimed to determine the effect and potential mechanism of poncirin on cisplatin resistance in osteosarcoma (OS) cells. CCK-8, flow cytometry analysis, and caspase-3/7 activity assays were used to evaluate cisplatin sensitivity. The expression changes of multidrug resistance 1 (MDR1), multidrug resistance-associated protein (MRP1), breast cancer resistance protein (BCRP), and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathway-related proteins were detected by RT-qPCR or western blot analyses. Results showed that poncirin exposure enhanced cisplatin sensitivity, promoted apoptosis, and increased caspase-3/7 activity in cisplatin-resistant OS cells. Poncirin decreased the expression levels of MDR1, MRP1, and BCRP, and inhibited the PI3K/Akt signaling in OS cells. Rescue experiments suggested that activation of the PI3K/Akt signaling by 740Y-P abolished poncirin-induced expression reduction of MDR1, MRP1, and BCRP, and attenuated the facilitative effects of poncirin on cisplatin sensitivity and apoptosis in cisplatin-resistant OS cells. In summary, poncirin suppressed cisplatin resistance in cisplatin-resistant OS cells by downregulating the expression of MDR1, MRP1, and BCRP through inhibiting the PI3K/Akt pathway.

BRM270 targets cancer stem cells and augments chemo-sensitivity in cancer

Over the past decade, a number of studies have demonstrated the resistance of cancer cells to conventional drugs and have recognized this as a major challenge in cancer therapy. While attempting to understand the underlying mechanisms of chemoresistance, several studies have suggested that the presence of cancer stem cells (CSCs) in tumors is one of the major pathways contributing toward resistance. Chemoresistance leads to cancer treatment failure and worsens the prognosis of patients. Natural herbal compounds are gaining attention as an alternative treatment strategy for cancer. These compounds may be effective against chemoresistant cells either alone or synergistically alongside conventional drugs, sensitizing cancer cells and enhancing the therapeutic efficacy. BRM270 is a natural compound made from seven herbal plant (Saururus chinensis, Citrus unshiu Markovich, Aloe vera, Arnebia euchroma, Portulaca oleracea, Prunella vulgaris var. lilacina and Scutellaria bacicalensis) extracts used in Asian traditional medicine and has the potential to target CSCs. Several studies have demonstrated the positive effects of BRM270 against chemoresistant cancer and its synergy alongside existing cancer drugs, including paclitaxel and gefitinib. These effects have been observed against various cancer types, including resistant non-small cell lung cancer (NSCLC), glioblastoma, multi-drug resistant osteosarcoma, cervical cancer, pancreatic cancer and hepatocarcinoma. The present review discusses the effects of BRM270 treatment against CSC-associated chemoresistance in common types of cancer.

Icaritin Exacerbates Mitophagy and Synergizes with Doxorubicin to Induce Immunogenic Cell Death in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) resistant to both chemotherapy and immunotherapy is among the deadliest malignancies. Doxorubicin widely used in transarterial chemotherapy in HCC can induce immunogenic cell death (ICD), but the resulting immunogenicity is still weak. We aim to seek a strategy for improving the efficacy of ICD in HCC based on an immunoregulatory drug called icaritin. Icaritin induced mitophagy and apoptosis to provoke ICD both in mouse Hepa1-6 and human Huh7 HCC cells. A combination of icaritin and doxorubicin with a molar ratio of 1:2 played a synergistic role in ICD induction. The poly lactic-co-glycolic acid (PLGA)-polyethylene glycol (PEG)-aminoethyl anisamide (AEAA) nanoparticle (NP) targeted codelivery of icaritin and doxorubicin remodeled the immunosuppressive tumor microenvironment and triggered a robust immune memory response, which efficiently improved anti-HCC effect at an early stage in mouse HCC model. In addition, the combo PLGA-PEG-AEAA NP together with lenvatinib significantly prolonged survival time of mice at the advanced stage of HCC. Collectively, our findings reveal an anti-HCC mechanism of icaritin on mitophagy and provide an effective immune-based therapeutic strategy for HCC.

Defying Multidrug Resistance! Modulation of Related Transporters by Flavonoids and Flavonolignans

Multidrug resistance (MDR) is a major challenge for the 21th century in both cancer chemotherapy and antibiotic treatment of bacterial infections. Efflux pumps and transport proteins play an important role in MDR. Compounds displaying inhibitory activity toward these proteins are prospective for adjuvant treatment of such conditions. Natural low-cost and nontoxic flavonoids, thanks to their vast structural diversity, offer a great pool of lead structures with broad possibility of chemical derivatizations. Various flavonoids were found to reverse both antineoplastic and bacterial multidrug resistance by inhibiting Adenosine triphosphate Binding Cassette (ABC)-transporters (human P-glycoprotein, multidrug resistance-associated protein MRP-1, breast cancer resistance protein, and bacterial ABC transporters), as well as other bacterial drug efflux pumps: major facilitator superfamily (MFS), multidrug and toxic compound extrusion (MATE), small multidrug resistance (SMR) and resistance-nodulation-cell-division (RND) transporters, and glucose transporters. Flavonoids and particularly flavonolignans are therefore highly prospective compounds for defying multidrug resistance.

Reversal of Multidrug Resistance in Cancer by Multi-Functional Flavonoids

Multidrug resistance (MDR) resulting from different defensive mechanisms in cancer is one of the major obstacles of clinical treatment. To circumvent MDR many reversal agents have been developed, but most of them fail in clinical trials due to severely adverse effects. Recently, certain natural products have been reported to overcome MDR, including flavonoids which are abundant in plants, foods, and herbs. The structure of flavonoids can be abbreviated as C6-C3-C6 (C for carbon), and further categorized into flavonoids, iso-flavonoids and neo-flavonoids, according to their structural backbones. Flavonoids possess multiple bioactivities, and a growing body of research has indicated that both flavonoids and iso-flavonoids can either kill or re-sensitize conventional chemotherapeutics to resistant cancer cells. Here, we summarize the research and discuss the underlying mechanisms, concluding that these flavonoids do not function as specific regulators of target proteins, but rather as multi-functional agents that negatively regulate the key factors contributing to MDR.

Icaritin: A Novel Natural Candidate for Hematological Malignancies Therapy

Hematological malignancies including leukemia and lymphoma can severely impact human health. With the current therapies combined with chemotherapy, stem cell transplantation, radiotherapy, and immunotherapy, the prognosis of hematologic malignancies improved significantly. However, most hematological malignancies are still incurable. Therefore, research for novel treatment options was continuing with the natural product as one source. Icaritin is a compound extracted from a traditional Chinese herb, Epimedium Genus, and demonstrated an antitumor effect in various neoplasms including hematological malignancies such as leukemia, lymphoma, and multiple myeloma. In hematological malignancies, icaritin showed multiple cytotoxic effects to induce apoptosis, arrest the cell cycle, inhibit proliferation, promote differentiation, restrict metastasis and infiltration, and suppress the oncogenic virus. The proved underlying mechanisms of the cytotoxic effects of icaritin are different in various cell types of hematological malignancies but associated with the critical cell signal pathway, including PI3K/Akt, JAK/STAT3, and MAPK/ERK/JNK. Although the primary target of icaritin is still unspecified, the existing evidence indicates that icaritin is a potential novel therapeutic agent for neoplasms as with hematological malignancies. Here, in the field of hematology, we reviewed the reported activity of icaritin in hematologic malignancies and the underlying mechanisms and recognized icaritin as a candidate for therapy of hematological malignancies.

Anti-myeloma Effects of Icariin Are Mediated Through the Attenuation of JAK/STAT3-Dependent Signaling Cascade

Because of the essential role of signal transducer and activator of transcription 3 (STAT3) in proliferation, anti-apoptosis, and chemoresistance of multiple myeloma (MM), we investigated whether icariin, a prenylated flavonol glycoside, inhibits both constitutive and inducible STAT3 activation in human myeloma cell lines. We noted that icariin could block constitutive STAT3 phosphorylation as well as its nuclear translocation and DNA binding ability in U266 cells. Icariin also suppressed IL-6-induced STAT3 activation through the inhibition of upstream kinases (Janus activated kinase-1 and -2, and c-Src). We found that icariin downregulated the protein expression of STAT3 downstream target gene products such as Bcl-2, Bcl-xl, survivin, IAP-1/2, COX-2, VEGF, and matrix metallopeptidase 9 (MMP-9) in a concentration-dependent manner. Moreover, this flavonoid also exhibited the capacity to significantly induce apoptosis and suppress proliferation of MM cells. Interestingly, this agent also significantly potentiated the apoptotic effects of bortezomib through the suppression of STAT3 activation in MM cells. Altogether, our data indicates that the potential application of icariin as a STAT3 blocker in myeloma therapy.