Chrysin Increases the Therapeutic Efficacy of Docetaxel and Mitigates Docetaxel-Induced Edema

PEGylation of Chrysin Improves Its Water Solubility while Preserving the In Vitro Biological Activity

Chrysin is a natural flavonoid that despite having numerous biological properties, its therapeutic value is limited due to its very low solubility in aqueous media. In this work, chrysin was conjugated with methoxypolyethylene glycols (mPEGs) of different molecular weights (350, 500, 750, and 2000 g/mol), affording PEGylated chrysins with high yields and excellent purities. In all cases, an increase in the water solubility of the conjugates was observed, which was highest when 500 g/mol of mPEG was used in the PEGylation reaction. Furthermore, in aqueous solution, PEGylated chrysins formed aggregates of ellipsoid shape. Electrochemical studies showed that the redox properties were conserved after PEGylation. While in vitro antibacterial and antifungal studies probed that the intrinsic activity was conserved, in vitro antitumor activities against HepG2 (liver carcinoma cells) and PC3 (prostate cancer cell) showed that PEGylated chrysins retained the cytotoxic activity and the ability of induction of apoptosis for the evaluated human cancer cells.

Co-administration of Chrysin and Luteolin with Cisplatin and Topotecan Exhibits a Variable Therapeutic Value in Human Cancer Cells, HeLa

Combinational treatment is a promising strategy for better cancer treatment outcomes. Chrysin and luteolin have demonstrated effective anticancer activity. Cisplatin and topotecan are commonly used for the treatment of human cancers. However, various side effects including drug resistance are an imperative restriction to use them as pharmacological therapy. Therefore, the aim was to use these agents in combination with flavones for better efficacy. In the present study, it was found that the combination of chrysin and cisplatin and luteolin and cisplatin significantly improved the anticancer effect as both the combinations showed synergistic interactions [combinational index (CI < 1)]. Remarkably, the combination of chrysin and luteolin with topotecan depicted the antagonistic interaction (CI > 1). Further, increased expression of the pro-apoptotic proteins Bax and caspase 8 and the inhibition of the antiapoptotic protein Bcl-2 were instituted in the synergistic doses (chrysin + cisplatin and luteolin + cisplatin), hence promoting apoptosis. Also, it was found that the synergistic combination inhibited the migration of HeLa cells by downregulation of metalloproteases and upregulation of TIMPs. However, there are no significant changes depicted in the antagonistic combinations which support their role in their antagonistic effects. Based on these results, it can be inferred that the two or more drug combinations need to be explored well for their interaction to enhance the therapeutic outcomes.

NF-κB in Cell Deaths, Therapeutic Resistance and Nanotherapy of Tumors: Recent Advances

The transcription factor nuclear factor-κB (NF-κB) plays a complicated role in multiple tumors. Mounting evidence demonstrates that NF-κB activation supports tumorigenesis and development by enhancing cell proliferation, invasion, and metastasis, preventing cell death, facilitating angiogenesis, regulating tumor immune microenvironment and metabolism, and inducing therapeutic resistance. Notably, NF-κB functions as a double-edged sword exerting positive or negative influences on cancers. In this review, we summarize and discuss recent research on the regulation of NF-κB in cancer cell deaths, therapy resistance, and NF-κB-based nano delivery systems.

Chrysin-Induced G Protein-Coupled Estrogen Receptor Activation Suppresses Pancreatic Cancer

Pancreatic cancer (PC) has a high mortality rate due to its poor prognosis and the possibility of surgical resection in patients with the disease. Importantly, adjuvant chemotherapy is necessary to improve PC prognosis. Chrysin, a natural product with anti-inflammatory, antioxidant, and anticancer properties, has been studied for several years. Our previous study demonstrated that chrysin induced G protein-coupled estrogen receptor (GPER) expression and regulated its activity in breast cancer. Herein, we investigated whether chrysin-induced GPER activation suppresses PC progression in MIA PaCa-2 cells and a xenograft model. To determine its mechanism of action, cytotoxicity and clonogenic assays, a FACS analysis, and Western blotting were performed. Furthermore, the delay in tumor growth was evaluated in the MIA PaCa-2-derived xenograft model. Tumor tissues were investigated by Western blotting, immunohistochemistry, and a proteomic analysis. Chrysin caused cell cycle arrest and significantly decreased cell viability. Following co-treatment with chrysin and 17β-estradiol, the inhibitory effect of chrysin on cell proliferation was enhanced. In the xenograft model, chrysin and G1 (a GPER agonist) significantly delayed tumor growth and reduced both Ki-67 (a proliferation marker) and c-Myc expressions in tumor tissues. The proteomic analysis of tumor tissues identified that rho-associated coiled-coil containing protein kinase 1 (ROCK1), transgelin 2 (TAGLN2), and FCH and Mu domain containing endocytic adaptor 2 (FCHO2) levels were significantly reduced in chrysin-treated tumor tissues. High ROCK1, TAGLN2, and FCHO2 expressions were indicative of low overall PC survival as found using the Kaplan–Meier plotter. In conclusion, our results suggest that chrysin suppresses PC progression through the activation of GPER and reductions in ROCK1, TAGLN2, and FCHO2 expressions.

The Potential Use of Propolis as a Primary or an Adjunctive Therapy in Respiratory Tract-Related Diseases and Disorders: A Systematic Scoping Review

Propolis is a resinous beehive product that is collected by the bees from plant resin and exudates, to protect and maintain hive homeostasis. Propolis has been used by humans therapeutically to treat many ailments including respiratory tract-related diseases and disorders. The aim of the present systematic scoping review is to evaluate the experimental evidence to support the use of propolis as a primary or an adjunctive therapy in respiratory tract-related diseases and disorders. After applying the exclusion criteria, 158 research publications were retrieved and identified from Scopus, Web of Science, Pubmed, and Google Scholar. The key themes of the included studies were pathogenic infection-related diseases and disorders, inflammation-related disorders, lung cancers, and adverse effects. Furthermore, the potential molecular and biochemical mechanisms of action of propolis in alleviating respiratory tract-related diseases and disorders are discussed. In conclusion, the therapeutic benefits of propolis have been demonstrated by various in vitro studies, in silico studies, animal models, and human clinical trials. Based on the weight and robustness of the available experimental and clinical evidence, propolis is effective, either as a primary or an adjunctive therapy, in treating respiratory tract-related diseases.

Side effect prediction based on drug-induced gene expression profiles and random forest with iterative feature selection

One in every ten drug candidates fail in clinical trials mainly due to efficacy and safety related issues, despite in-depth preclinical testing. Even some of the approved drugs such as chemotherapeutics are notorious for their side effects that are burdensome on patients. In order to pave the way for new therapeutics with more tolerable side effects, the mechanisms underlying side effects need to be fully elucidated. In this work, we addressed the common side effects of chemotherapeutics, namely alopecia, diarrhea and edema. A strategy based on Random Forest algorithm unveiled an expression signature involving 40 genes that predicted these side effects with an accuracy of 89%. We further characterized the resulting signature and its association with the side effects using functional enrichment analysis and protein-protein interaction networks. This work contributes to the ongoing efforts in drug development for early identification of side effects to use the resources more effectively.

Developing nutritional component chrysin as a therapeutic agent: Bioavailability and pharmacokinetics consideration, and ADME mechanisms

Chrysin is a promising naturally occurring flavonoid mainly found in honey and propolis. Although chrysin's biological activities have been demonstrated and the mechanism of actions has been determined using in vitro and in vivo models, results from the current clinical studies were largely negative. A potential reason for chrysin's low efficacy in humans is poor oral bioavailability. In this paper, we reviewed the preclinical and clinical pharmacokinetics studies of chrysin and analyzed the mechanism of poor in vivo efficacy with emphasis on its bioavailability and ADME mechanism. Low aqueous solubility, rapid metabolism mediated by UGTs and SULT, efficient excretion through efflux transporters including BCRP and MRP2 are the major reasons causing poor systemic bioavailability for chrysin. However, because of efficient enterohepatic recycling facilitated by phase II metabolism and efflux, chrysin's bioavailability in the low GI tract is high. Thus, chrysin can be ideal for treating diseases in the terminal ileum and colon (e.g., carcinoma, local infection) since it is localized in the lower GI tract with limited delivery to other organs.

Combination effect of curcumin with docetaxel on the PI3K/AKT/mTOR pathway to induce autophagy and apoptosis in esophageal squamous cell carcinoma

BACKGROUND

Docetaxel (DTX) is widely used to treat many malignant tumors but has many adverse effects. Curcumin (CUR) also has effects on a variety of tumor cells and can reduce the toxicity and side effects of chemotherapy drugs and the occurrence of drug resistance. However, the combination of CUR and DTX for treating esophageal cancer has not been reported.

METHODS

Human esophageal squamous cell carcinoma (ESCC) KYSE150 and KYSE510 cells were treated with CUR or DTX alone or both drugs and cancer cell viability was detected by CCK8, apoptosis, scratch-healing and migration assays. Electron microscopy and Western blots were used. In vivo experiments were used observe anti-tumor effects.

RESULTS

CUR combined with DTX significantly inhibited the viability and migration of esophageal cancer cells (P<0.01) and further promoted the apoptosis of cancer cells. In addition, CUR induced autophagy in esophageal cancer cells when combined with DTX. DTX combined with CUR may induce apoptosis and autophagy by inhibiting the PI3K/AKT/mTOR signaling pathway. The compound 3-methyladenine (3MA) inhibited the autophagy induced by DTX and CUR (DC), further accelerated apoptosis and inhibited the proliferation of esophageal cancer cells when combined with DC.

CONCLUSION

CUR combined with DTX induced apoptosis and autophagy of ESCC and probably worked through the PI3K/AKT/mTOR signaling pathway. The combination of the autophagy inhibitor, CUR and DTX may become a new treatment strategy for esophageal cancer.

Potentiating activities of chrysin in the therapeutic efficacy of 5-fluorouracil in gastric cancer cells

The incidence and mortality rates of gastric cancer rank among the highest five of all cancer types worldwide. The chemotherapeutic agent 5-fluorouracil (5-FU) is the gold standard for treating gastric cancer, but its efficacy is limited due to high rates of resistance. To improve the therapeutic efficacy of 5-FU and overcome its resistance, the synergistic effect of chrysin with 5-FU was investigated and its mechanism was elucidated. Chrysin was co-administered with 5-FU in AGS cells and 5-FU-resistant AGS cells (AGS/FR). Cytotoxicity was investigated using MTT assay, followed by calculating the combination index (CI). Several biomarkers were detected using western blotting analysis. Apoptosis and cell cycle distribution were measured by flow cytometry. The combination of chrysin and 5-FU significantly increased cytotoxicity more than chrysin or 5-FU alone. 5-FU induced apoptosis through p53-p21 activity, while chrysin arrested the cell cycle in the G2/M phase. The combination of chrysin and 5-FU showed an anticancer effect via S phase arrest. The results indicated that chrysin and 5-FU exhibited anticancer properties via different pathways. Furthermore, the present study found that chrysin enhanced the chemotherapeutic effect of 5-FU in AGS/FR cells. In the resistant cells, the combination of chrysin and 5-FU improved the anticancer effect via G2/M phase arrest. These findings indicated that chrysin potentiated the chemotherapeutic effect of 5-FU in gastric cancer AGS and AGS/FR cells via cell cycle arrest. Therefore, chrysin may be used to treat gastric cancers that have become resistant to 5-FU.

Nanoformulations to Enhance the Bioavailability and Physiological Functions of Polyphenols

Polyphenols are micronutrients that are widely present in human daily diets. Numerous studies have demonstrated their potential as antioxidants and anti-inflammatory agents, and for cancer prevention, heart protection and the treatment of neurodegenerative diseases. However, due to their vulnerability to environmental conditions and low bioavailability, their application in the food and medical fields is greatly limited. Nanoformulations, as excellent drug delivery systems, can overcome these limitations and maximize the pharmacological effects of polyphenols. In this review, we summarize the biological activities of polyphenols, together with systems for their delivery, including phospholipid complexes, lipid-based nanoparticles, protein-based nanoparticles, niosomes, polymers, micelles, emulsions and metal nanoparticles. The application of polyphenol nanoparticles in food and medicine is also discussed. Although loading into nanoparticles solves the main limitation to application of polyphenolic compounds, there are some concerns about their toxicological safety after entry into the human body. It is therefore necessary to conduct toxicity studies and residue analysis on the carrier.

Broad-Spectrum Preclinical Antitumor Activity of Chrysin: Current Trends and Future Perspectives

Pharmacological profile of phytochemicals has attracted much attention to their use in disease therapy. Since cancer is a major problem for public health with high mortality and morbidity worldwide, experiments have focused on revealing the anti-tumor activity of natural products. Flavonoids comprise a large family of natural products with different categories. Chrysin is a hydroxylated flavonoid belonging to the flavone category. Chrysin has demonstrated great potential in treating different disorders, due to possessing biological and therapeutic activities, such as antioxidant, anti-inflammatory, hepatoprotective, neuroprotective, etc. Over recent years, the anti-tumor activity of chrysin has been investigated, and in the present review, we provide a mechanistic discussion of the inhibitory effect of chrysin on proliferation and invasion of different cancer cells. Molecular pathways, such as Notch1, microRNAs, signal transducer and activator of transcription 3 (STAT3), nuclear factor-kappaB (NF-κB), PI3K/Akt, MAPK, etc., as targets of chrysin are discussed. The efficiency of chrysin in promoting anti-tumor activity of chemotherapeutic agents and suppressing drug resistance is described. Moreover, poor bioavailability, as one of the drawbacks of chrysin, is improved using various nanocarriers, such as micelles, polymeric nanoparticles, etc. This updated review will provide a direction for further studies in evaluating the anti-tumor activity of chrysin.

Plant flavone Chrysin as an emerging histone deacetylase inhibitor for prosperous epigenetic-based anticancer therapy

Aberrations in epigenetic mechanisms provide a fertile platform for tumour initiation and progression. Thus, agents capable of modulating the epigenetic environment of neoplasms will be a valuable addition to the anticancer therapeutics. Flavones are emerging as befitting anticancer agents due to their inherent antioxidant activity and the ability to restrain epi-targets namely histone deacetylases (HDACs). HDACs have broader implications in pathogenesis of various cancers. Chrysin, a flavone possessing the ability to inhibit HDACs could prove as a potential anticancer drug. Thus, in this article we focussed on Chrysin and its distinct antineoplastic effect against bellicose malignancies including lung, colorectal, cervical, gastric, melanoma, hepatocellular carcinoma and breast cancer. The underlying signalling cascades triggered by Chrysin for inducing cytotoxic effect in these cancer models are discussed. Importantly, approaches towards combinatorial treatments by Chrysin and commercial anticancer agents are taken into account. The downstream molecular mechanism aroused by combined therapy for abrogating onerous cancer chemoresistance is delineated as well. Moreover, the nano-combinatorial approach involving co-encapsulation of Chrysin with other herbal and non-herbal agents for clinical excellence is elucidated.

Protective effects of Chrysin against memory impairment, cerebral hyperemia and oxidative stress after cerebral hypoperfusion and reperfusion in rats

Stroke is devastating and a leading cause of morbidity and mortality worldwide. Cerebral ischemia-reperfusion and its subsequent reactive hyperemia lead to neuronal damage in the hippocampus and cognitive decline. Chrysin (5, 7-dihydroxyflavone) is a well-known member of the flavonoid family with antioxidant and neuroprotective effects. Therefore, in the present study, the aim was to investigate whether chrysin will be able to recover the brain function caused by ischemia-reperfusion (I/R) in rats. Adult male Wistar rats (250-300 g) were randomly divided into five groups: and submitted to cerebral I/R or a sham surgery after three-weeks of pretreatment with chrysin (CH; 10, 30 and 100 mg/kg; P.O.) and/or normal saline containing %5 DMSO. Subsequently, sensorimotor scores, cognition, local cerebral blood flow, extracellular single unit, and histological parameters were evaluated following I/R. Hippocampus was used to evaluate biomarkers including: oxidative stress parameters and prostaglandin E2 (PGE2) using ELISA kits. Data showed that pretreatment with chrysin significantly improved sensorimotor signs, passive avoidance memory, and attenuated reactive hyperemia, and increased the average number of spikes/bin (p < 0.001). Furthermore, chrysin pre-treatment significantly decreased the levels of MDA, NO, and PGE2 (p < 0. 001), while increased the levels of GPX and the number of surviving cells in the hippocampal CA1 region (p < 0.01, p < 0.001; respectively). This study demonstrates that chrysin may have beneficial effects in the treatment of cognitive impairment and help recover the brain dysfunction induced by I/R.

Upregulation of G Protein-Coupled Estrogen Receptor by Chrysin-Nanoparticles Inhibits Tumor Proliferation and Metastasis in Triple Negative Breast Cancer Xenograft Model

Triple-negative breast cancer (TNBC) is associated with a high mortality rate among women globally. TNBC shows a high rate of recurrence and distant metastasis. Particularly, the chemotherapy is limited because hormone therapy of breast cancer is ineffective. Thus, an effective chemotherapeutic agent is needed for tumor suppression. Chrysin-nanoparticles (chrysin-NPs) were investigated for their inhibitory effect on a MDA-MB-231-derived xenograft model. To gain insight into the underlying mechanisms, we conducted human matrix metalloproteinase (MMP) array, western blot, and immunohistochemistry analysis. Furthermore, in vivo imaging was used to monitor the chemotherapeutic efficacy of chrysin-NPs in a metastasis mouse model. Chrysin-NPs significantly inhibited the proliferation of MDA-MB-231 cells via the PI3K/JNK pathway and induced cell death through the p53-apoptosis pathway, leading to delayed MDA-MB-231-derived tumor growth. Interestingly, chrysin-NPs significantly induced G protein-coupled estrogen receptor (GPER) expression, which suppresses MMPs and NF-κB expression. Chrysin-NPs acted as effective metastasis inhibitors. Our results suggest that chrysin-NPs may be used as an effective adjuvant formulation to inhibit TNBC progression.

Chrysin enhances anticancer drug-induced toxicity mediated by the reduction of claudin-1 and 11 expression in a spheroid culture model of lung squamous cell carcinoma cells

The aberrant expression of claudins (CLDNs), which are tight junctional proteins, is seen in various solid tumors, but the regulatory mechanisms and their pathophysiological role are not well understood. Both CLDN1 and CLDN11 were highly expressed in human lung squamous cell carcinoma (SCC). Chrysin, found in high concentration in honey and propolis, decreased CLDN1 and CLDN11 expression in RERF-LC-AI cells derived from human lung SCC. The phosphorylation level of Akt was decreased by chrysin, but those of ERK1/2 and c-Jun were not. LY-294002, an inhibitor of phosphatidylinositol 3-kinase, inhibited the phosphorylation of Akt and decreased the expression levels of CLDN1 and CLDN11. The association between phosphoinositide-dependent kinase 1 (PDK1) and Akt was inhibited by chrysin, but the phosphorylation of PDK1 was not. Immunoprecipitation and quartz-crystal microbalance assays revealed that biotinylated-chrysin binds directly to Akt. The knockdown of CLDN1 and CLDN11 using small interfering RNAs increased the transepithelial flux of doxorubicin (DXR), an anthracycline anticancer drug. Similarly, both chrysin and LY-294002 increased DXR flux. Neither CLDN1 knockdown, CLDN11 knockdown, nor chrysin changed the anticancer drug-induced cytotoxicity in a two-dimensional culture model, whereas they enhanced cytotoxicity in a spheroid culture model. Taken together, chrysin may bind to Akt and inhibit its phosphorylation, resulting in the elevation of anticancer drug-induced toxicity mediated by reductions in CLDN1 and CLDN11 expression in RERF-LC-AI cells. We suggest that chrysin may be useful as an adjuvant chemotherapy in lung SCC.

Docetaxel increases the risk of severe infections in the treatment of non-small cell lung cancer: a meta-analysis

The purpose of this study was to determine whether docetaxel increases the risk of severe infections in patients with non-small cell lung cancer. A thorough literature search of the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases was performed (up to February 28, 2017) without any language restrictions. In addition, we searched the www.clinicaltrials.gov website and checked each reference listed in the included studies, relevant reviews and guidelines. We also included randomized controlled trials that reported severe infections in patients with non-small cell lung cancer who were administered docetaxel. A meta- analysis was conducted using relative risk and random effects models in Stata 14.0 software. Sensitivity analysis and meta-regression were performed using Stata 14.0 software. We identified 354 records from the initial search, and this systematic review ultimately included 43 trials with 12,447 participants. The results of our meta- analysis showed that docetaxel increased the risk of severe infections [relative risk: 2.10, 95% confidence interval: 1.51-2.93, I² = 69.6%, P = 0.000]. Meta-regression analysis indicated that the type of intervention was a major source of heterogeneity. Our systematic review and meta-analysis suggest that docetaxel is associated with the risk of severe infections.

Nanoscale modification of chrysin for improved of therapeutic efficiency and cytotoxicity

Chrysin, as a flavone, is a promising drug candidate because of its multifaceted properties, such as anti-inflammatory, antioxidant and anticancer. However, its poor bioavailability is a bottleneck for pharmaceutical applications. To enhance the bioactive effects, chrysin-loaded poly (D,L-lactic-co-glycolic acid) and polyvinyl alcohol were successfully prepared to overcome problems associated with chrysin. The properties of modified nanochrysin were analysed by in vitro dissolution study, XRD, FTIR and SEM. Free radical scavenging potentials of the modified nanochrysin against DPPH were confirmed based on its stable antioxidant effects. A DNA instability enhancement was observed after H₂O₂ exposure, whereas chrysin decreased the H₂O₂ activity, and modified nanochrysin was more potent in this regard. Blood compatibility on red blood cells was confirmed by haemolytic and in vitro cytotoxicity assays. The in vitro anticancer activity of the modified nanochrysin towards MCF-7 and SKOV-3 cell lines using various parameters was investigated. The nanochrysin was found to exert cell growth arrest against both cancer cells in a dose-dependent manner. IC₅₀ value was significantly decreased in nanochrysin in comparison with pure chrysin and induced apoptotic cell death pathway. The results of this study suggest that the nanochrysin might be used for medical applications and offer a beneficial formulation for chemotherapy.

Chrysin: Sources, beneficial pharmacological activities, and molecular mechanism of action

In recent years, public and scientific interest in plant flavonoids has tremendously increased because of their postulated health benefits. This review was mainly focuses on the flavone chrysin (5,7-dihydroxyflavone), which occurs naturally in many plants, honey, and propolis. A number of in vitro and in vivo studies have revealed the therapeutic effects of chrysin against various diseases. In general, chrysin exhibits many biological activities and pharmacological effects, including antioxidant, anti-inflammatory, anticancer, and antiviral activities. Moreover, many studies have reported on the bioavailability of chrysin. Because of its compromised bioavailability and enhanced protein stability, chrysin solid lipid nanoparticle (SLN) synthesis avoids proteolytic degradation and sustained release of drug delivery. To clarify the mechanism of action of chrysin, researchers have investigated the structural binding relationship of chrysin through the docking computation method.

Improved chemotherapeutic efficacy of injectable chrysin encapsulated by copolymer nanoparticles

Chrysin is a flavone that is found in several plants and in honeycomb and possesses various biological activities. However, its low solubility means it has poor bioavailability, which must be resolved to enable its pharmaceutical applications. In the present study, chrysin was incorporated into methoxy poly(ethylene glycol)-β-polycaprolactone nanoparticles (chrysin-NPs) using the oil-in-water technique in order to overcome problems associated with chrysin. The properties of chrysin-NPs were analyzed, and their anticancer effects were investigated in vitro and in vivo. Chrysin-NPs were 77 nm sized (as determined by dynamic laser light scattering) and showed a monodisperse distribution. The zeta potential of chrysin-NPs was -2.22 mV, and they were spherically shaped by cryo-transmission electron microscopy (cryo-TEM). The loading efficiency of chrysin-NPs was 46.96%. Chrysin-NPs retained the cytotoxicity of chrysin in A549 cells. The therapeutic efficacies of chrysin-NPs were compared with those of chrysin in an A549-derived xenograft mouse model. Chrysin-NPs were intravenously injected at a 10 times lower dosage than chrysin 3 times per week (q2d×3/week). However, free chrysin was orally administrated 5 times per week (q1d×5/week). Chrysin-NP-treated group showed significant tumor growth delay, which was similar to that of chrysin-treated group, despite the considerably lower total dosage. These results suggest that the injectable chrysin-NPs enhance therapeutic efficacy in vivo and offer a beneficial formulation for chemotherapy.

Sipuleucel-T and Androgen Receptor-Directed Therapy for Castration-Resistant Prostate Cancer: A Meta-Analysis

New treatments, such as sipuleucel-T and androgen receptor- (AR-) directed therapies (enzalutamide (Enz) and abiraterone acetate (AA)), have emerged and been approved for the management of castration-resistant prostate cancer (CRPC). There are still debates over their efficacy and clinical benefits. This meta-analysis aimed to investigate the efficacy and safety of sipuleucel-T and AR-directed therapies in patients with CRPC. RevMan 5.1 was used for pooled analysis and analysis of publication bias. Seven studies were included in the meta-analysis, with three studies in sipuleucel-T (totally 737 patients, 488 patients in treatment group, and 249 patients in placebo group) and four in AR-directed therapies (totally 5,199 patients, 3,015 patients in treatment group, and 2,184 patients in placebo group). Treatment with sipuleucel-T significantly improved overall survival in patients with CRPC and was not associated with increased risk of adverse event of grade ≥3 (p > 0.05). However, treatment with sipuleucel-T did not improve time-to-progression and reduction of prostate-specific antigen (PSA) level ≥50% was not significantly different from that with placebo. AR-directed therapies significantly improved overall survival in patients with CRPC and improved time-to-progression and reduction of PSA level ≥50%. AR-directed therapies did not increase risk of adverse event of grade ≥3 (p > 0.05).