New tricks of old drugs: Repurposing non-chemo drugs and dietary phytochemicals as adjuvants in anti-tumor therapies

Phytochemicals as Novel Therapeutics for Triple-Negative Breast Cancer: A Comprehensive Review of Current Knowledge

Triple-negative breast cancer is a characteristic subtype of breast cancer that lacks the estrogen receptor, human epidermal growth factor receptor 2, and progesterone receptor. Because of its highly diverse subtypes, increased metastasis capability, and poor prognosis, the risk of mortality for people with triple-negative breast cancers is high as compared with other cancers. Chemotherapy is currently playing a major role in treating triple-negative breast cancer patients; however, poor prognosis due to drug resistance is causing serious concern. Recent studies on several phytochemicals derived from various plants being used in Traditional Chinese Medicine, Traditional Korean Medicine, Ayurveda (Traditional Indian Medicine), and so on, have demonstrated to be a promising agent as a viable therapy against triple-negative breast cancer. Phytochemicals categorized as alkaloids, polyphenols, terpenoids, phytosterols, and organosulfur compounds have been demonstrated to reduce cancer cell proliferation and metastasis by activating various molecular pathways, thereby reducing the spread of triple-negative breast cancer. This review analyzes the molecular mechanisms by which various phytochemicals fight triple-negative breast cancer and offers a perspective on the difficulties and potential prospects for treating triple-negative breast cancer with various phytochemicals.

Emerging role of tumor microenvironmental nutrients and metabolic molecules in ferroptosis: Mechanisms and clinical implications

In recent years, ferroptosis has gradually attracted increasing attention because of its important role in tumors. Ferroptosis resistance is an important cause of tumor metastasis, recurrence and drug resistance. Exploring the initiating factors and specific mechanisms of ferroptosis has become a key strategy to block tumor progression and improve drug sensitivity. As the external space in direct contact with tumor cells, the tumor microenvironment has a great impact on the biological function of tumor cells. The relationships between abnormal environmental characteristics (hypoxia, lactic acid accumulation, etc.) in the microenvironment and ferroptosis of tumor cells has not been fully characterized. This review focuses on the characteristics of the tumor microenvironment and summarizes the mechanisms of ferroptosis under different environmental factors, aiming to provide new insights for subsequent targeted therapy. Moreover, considering the presence of anticancer drugs in the microenvironment, we further summarize the mechanisms of ferroptosis to provide new strategies for the sensitization of tumor cells to drugs.

Riboflavin protects against pancreatic cancer metastasis by targeting TGF-β receptor 1

The inhibition of transforming growth factor-β1 (TGF-β1) signaling by targeting TGF-β receptor 1 (TβR1) has been considered as an ideal approach for the prevention of pancreatic cancer metastasis. Utilizing a pharmacophore model for TβR1 inhibitors, candidate compounds with the potential TβR1 binding ability were screened from the U.S. Food and Drug Administration (FDA) database, and riboflavin (RF) with a highest fit value was chosen to investigate its binding ability to TβR1 and effect on TGF-β1 signaling in pancreatic cancer cells. Molecular docking and cellular thermal shift assay (CETSA) proved that RF at pharmacological concentrations could directly bind to TβR1. Further studies showed that pharmacological concentrations of RF in vitro could block TGF-β1 signaling, suppress the migration and invasion, and prevent epithelial-mesenchymal transition (EMT) process of pancreatic cancer cells in the absence or presence of TGF-β1 stimulation, indicating that RF presented anti-metastatic effect in pancreatic cancer cells. Knockdown of TβR1 could significantly attenuate the effects of RF on the migration and EMT process in pancreatic cancer cells, further confirming that the anti-metastatic effect of RF was achieved by blocking TGF-β1 signaling after binding to TβR1. Moreover, in a mouse model of pancreatic cancer metastasis, it was certified that RF administration could block lung and liver metastases, TGF-β1 signaling and EMT process of pancreatic cancer in vivo. In summary, our findings showed that RF could block TGF-β1 signaling by directly binding to TβR1, thereby suppressing the metastasis of pancreatic cancer cells by inhibiting EMT process both in vitro and in vivo.

A copper-loaded self-assembled nanoparticle for disturbing the tumor redox balance and triple anti-tumor therapy

Both chemodynamic therapy and photodynamic therapy, based on the production of reactive oxygen (ROS), have excellent potential in cancer therapy. However, the abnormal redox homeostasis in tumor cells, especially the overexpressed glutathione (GSH) could scavenge ROS and reduce the anti-tumor efficiency. Therefore, it is essential to develop a simple and effective tumor-specific drug delivery system for modulating the tumor microenvironment (TME) and achieving synergistic therapy at the tumor site. In this study, self-assembled nanoparticles (named CDZP NPs) were developed using copper ion (Cu2+), doxorubicin (Dox), zinc phthalocyanine (ZnPc) and a trace amount of poly(2-(di-methylamino)ethylmethacrylate)-poly[(R)-3-hydroxybutyrate]-poly(2-(dimethylamino)ethylmethacrylate) (PDMAEMA-PHB-PDMAEMA) through chelation, π-π stacking and hydrophobic interaction. These triple factor-responsive (pH, laser and GSH) nanoparticles demonstrated unique advantages through the synergistic effect. Highly controllable drug release ensured its effectiveness at the tumor site, Dox-induced chemotherapy and ZnPc-mediated fluorescence (FL) imaging exhibited the distribution of nanoparticles. Meanwhile, Cu2+-mediated GSH-consumption not only reduced the intracellular ROS elimination but also produced Cu+ to catalyze hydrogen peroxide (H2O2) and generated hydroxyl radicals (˙OH), thereby enhancing the chemodynamic and photodynamic therapy. Herein, this study provides a green and relatively simple method for preparing multifunctional nanoparticles that can effectively modulate the TME and improve synergetic cancer therapy.

Liensinine, a Novel and Food-Derived Compound, Exerts Potent Antihepatoma Efficacy via Inhibiting the Kv10.1 Channel

Plant metabolites from natural product extracts offer unique advantages against carcinogenesis in the development of drugs. The target-based virtual screening from food-derived compounds represents a promising approach for tumor therapy. In this study, we performed virtual screening to target the presumed inhibitor-binding pocket and identified a highly potent Kv10.1 inhibitor, liensinine (Lien), which can inhibit the channel in a dose-dependent way with an IC50 of 0.24 ± 0.07 μM. Combining molecular dynamics simulations with mutagenesis experiments, our data show that Lien interacts with Kv10.1 by binding with Y539, T543, D551, E553, and H601 in the C-linker domain of Kv10.1. In addition, the interaction of sequence alignment and 3D structural modeling revealed differences between the C-linker domain of the Kv10.1 channel and the Kv11.1 channel. Furthermore, antitumor experiments revealed that Lien suppresses the proliferation and migration of HCC both in vitro and in vivo. In summary, the food-derived compound, Lien, may serve as a lead compound for antihepatoma therapeutic drugs targeting Kv10.1.

Silibinin Induces Both Apoptosis and Necroptosis with Potential Anti-tumor Efficacy in Lung Cancer

BACKGROUND

The incidence of lung cancer is steadily on the rise, posing a growing threat to human health. The search for therapeutic drugs from natural active substances and elucidating their mechanism have been the focus of anti-tumor research.

OBJECTIVE

Silibinin (SiL) has been shown to be a natural product with a wide range of pharmacological activities, including anti-tumour activity. In our work, SiL was chosen as a possible substance that could inhibit lung cancer. Moreover, its effects on inducing tumor cell death were also studied.

METHODS

CCK-8 analysis and morphological observation were used to assess the cytotoxic impacts of SiL on lung cancer cells in vitro. The alterations in mitochondrial membrane potential (MMP) and apoptosis rate of cells were detected by flow cytometry. The level of lactate dehydrogenase (LDH) release out of cells was measured. The expression changes of apoptosis or necroptosis-related proteins were detected using western blotting. Protein interactions among RIPK1, RIPK3, and MLKL were analyzed using the co-immunoprecipitation (co-IP) technique. Necrosulfonamide (Nec, an MLKL inhibitor) was used to carry out experiments to assess the changes in apoptosis following the blockade of cell necroptosis. in vitro, SiL was evaluated for its antitumor effects using LLC tumor-bearing mice with mouse lung cancer.

RESULTS

With an increased dose of SiL, the proliferation ability of A549 cells was considerably inhibited, and the accompanying cell morphology changed. The results of flow cytometry showed that after SiL treatment, MMP levels decreased, and the proportion of cells undergoing apoptosis increased. There was an increase in cleaved caspase-9, caspase-3, and PARP, with a down-regulation of Bcl-2 and an up-regulation of Bax. In addition, the amount of LDH released from the cells increased following SiL treatment, accompanied by augmented expression and phosphorylation levels of necroptosis-related proteins (MLKL, RIPK1, and RIPK3), and the co-IP assay further confirmed the interactions among these three proteins, indicating the necrosome formation induced by SiL. Furthermore, Nec increased the apoptotic rate of SiL-treated cells and aggravated the cytotoxic effect of SiL, indicating that necroptosis blockade could switch cell death to apoptosis and increase the inhibitory effect of SiL on A549 cells. In LLC-bearing mice, gastric administration of SiL significantly inhibited tumor growth, and H&E staining showed significant damage to the tumour tissue. The results of the IHC showed that the expression of RIPK1, RIPK3, and MLKL was more pronounced in the tumor tissue.

CONCLUSIONS

This study confirmed the dual effect of SiL, as it can induce both biological processes, apoptosis and necroptosis, in lung cancer. SiL-induced apoptosis involved the mitochondrial pathway, as indicated by changes in caspase-9, Bcl-2, and Bax. Necroptosis may be activated due to the changes in the expression of associated proteins in tumour cells and tissues. It has been observed that blocking necroptosis by SiL increased cell death efficiency. This study helps clarify the anti-tumor mechanism of SiL against lung cancer, elucidating its role in the dual induction of apoptosis and necroptosis. Our work provides an experimental basis for the research on cell death induced by SiL and reveals its possible applications for improving the management of lung cancer.

Diallyl trisulfide inhibits gastric cancer stem cell properties through ΔNp63/sonic hedgehog pathway

Gastric cancer is one of the deadliest malignant tumors, and half of the patients develop recurrences or metastasis within 5 years after eradication therapy. Cancer stem cells (CSCs) are considered to be important in this progress. The sonic hedgehog (SHH) pathway plays an important role in the maintenance of gastric CSCs characteristics. The p63 proteins are vital transcription factors belonging to the p53 family, while their functions in regulating CSCs remain unclear. The preventive effects of dietary diallyl trisulfide (DATS) against human gastric cancer have been verified. However, whether DATS can target gastric CSCs are poorly understood. Here, we investigated the role of ΔNp63/SHH pathway in gastric CSCs and the inhibitory effect of DATS on gastric CSCs via ΔNp63/SHH pathway. We found that ΔNp63 was upregulated in serum-free medium cultured gastric tumorspheres compared with the parental cells. Overexpression of ΔNp63 elevated the self-renewal capacity and CSC markers' levels in gastric sphere-forming cells. Furthermore, we found that ΔNp63 directly bound to the promoter region of Gli1, the key transcriptional factor of SHH pathway, to enhance its expression and to activate SHH pathway. In addition, it was revealed that DATS effectively inhibited gastric CSC properties both in vitro and in vivo settings. Activation of SHH pathway attenuated the suppressive effects of DATS on the stemness of gastric cancer. Moreover, DATS suppression of gastric CSC properties was also diminished by ΔNp63 upregulation through SHH pathway activation. These findings illustrated the role of ΔNp63/SHH pathway in DATS inhibition of gastric cancer stemness. Taken together, the present study suggested for the first time that DATS inhibited gastric CSCs properties by ΔNp63/SHH pathway.

Challenges and Opportunities for Celecoxib Repurposing

Drug repositioning, also known as drug repurposing, reprofiling, or rediscovery, is considered to be one of the most promising strategies to accelerate the development of new original drug products. Multiple examples of successful rediscovery or therapeutic switching of old molecules that did not show clinical benefits or safety in initial trials encourage the following of the discovery of new therapeutic pathways for them. This review summarizes the efforts that have been made, mostly over the last decade, to identify new therapeutic targets for celecoxib. To achieve this goal, records gathered in MEDLINE PubMed and Scopus databases along with the registry of clinical trials by the US National Library of Medicine at the U.S. National Institutes of Health were explored. Since celecoxib is a non-steroidal anti-inflammatory drug that represents the class of selective COX-2 inhibitors (coxibs), its clinical potential in metronomic cancer therapy, the treatment of mental disorders, or infectious diseases has been discussed. In the end, the perspective of a formulator, facing various challenges related to unfavorable physicochemical properties of celecoxib upon the development of new oral dosage forms, long-acting injectables, and topical formulations, including the latest trends in the pharmaceutical technology, such as the application of mesoporous carriers, biodegradable microparticles, lipid-based nanosystems, or spanlastics, was presented.

Vibsane-type diterpenoids from Viburnum odoratissimum inhibit hepatocellular carcinoma cells via the PI3K/AKT pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, with an elevated danger of metastasis and a short survival rate. Vibsane-type diterpenoids with novel structures possess marked antitumor activities against multiple cancer cells. However, the exact mechanism is poorly unclear.

PURPOSE

To assess the antitumor mechanism of vibsane-type diterpenoids derived from Viburnum odoratissimum (V. odoratissimum) against HCC cells in vitro and in vivo.

METHODS

The main constituents in the ethyl acetate extract of V. odoratissimum (EAVO) were identified by LC-MS/MS. The antiproliferative activity of EAVO in vitro was evaluated by MTT assays. Annexin V-FITC/PI, AO/EB, and Hoechst 33,258 staining were employed to detect apoptosis. JC-1 fluorescence dye was used to detect the mitochondrial membrane potential (MMP). The levels of intracellular ROS and mitochondrial superoxides were assessed by H₂DCF-DA and MitoSox staining, respectively. The levels of oxidative stress were determined by ROS Green™ H₂O₂ probe, hydroxyphenyl fluorescein (HPF), and the C11 BODIPY 581/591 fluorescent probe. Transcriptomics was performed to investigate the antitumor mechanism of EAVO in HCC. The molecular mechanism by which EAVO suppressed HCC cells was verified by Western blot, RT-PCR, and HTRF® KinEASE™-STK S3 kits. The efficacy and safety of EAVO in vivo were evaluated using Hep3B xenograft models.

RESULTS

Vibsane-type diterpenoids were the main constituents of EAVO by LC-MS/MS. EAVO suppressed proliferation, aggravated oxidative stress, and promoted apoptosis in HCC cells. Moreover, EAVO dramatically inhibited tumor growth in Hep3B xenograft models. Transcriptomics results indicated that EAVO inhibited HCC cell proliferation by regulating the PI3K/AKT pathway. Vibsanin B, vibsanol I, and vibsanin S isolated from EAVO was used to further verify the antitumor activity of vibsane-type diterpenoids subsequently. Interestingly, the kinase results showed that vibsanin B and vibsanol I exhibited vital AKT kinase inhibitory activities.

CONCLUSIONS

Collectively, this study provided a comprehensive mechanism overview of vibsane-type diterpenoids against HCC cells in vitro and in vivo. It also laid a foundation for further antitumor investigation of vibsane-type diterpenoids in V. odoratissimum.

Electrospun Core–Sheath Nanofibers with Variable Shell Thickness for Modifying Curcumin Release to Achieve a Better Antibacterial Performance

The inefficient use of water-insoluble drugs is a major challenge in drug delivery systems. Core–sheath fibers with various shell thicknesses based on cellulose acetate (CA) were prepared by the modified triaxial electrospinning for the controlled and sustained release of the water-insoluble Chinese herbal active ingredient curcumin. The superficial morphology and internal structure of core–sheath fibers were optimized by increasing the flow rate of the middle working fluid. Although the prepared fibers were hydrophobic initially, the core–sheath structure endowed fibers with better water retention property than monolithic fibers. Core–sheath fibers had flatter sustained-release profiles than monolithic fibers, especially for thick shell layers, which had almost zero-order release for almost 60 h. The shell thickness and sustained release of drugs brought about a good antibacterial effect to materials. The control of flow rate during fiber preparation is directly related to the shell thickness of core–sheath fibers, and the shell thickness directly affects the controlled release of drugs. The fiber preparation strategy for the precise control of core–sheath structure in this work has remarkable potential for modifying water-insoluble drug release and improving its antibacterial performance.

Drug repurposing: An emerging strategy in alleviating skin cancer

Skin cancer is one of the most common forms of cancer. Several million people are estimated to have affected with this condition worldwide. Skin cancer generally includes melanoma and non-melanoma with the former being the most dangerous. Chemotherapy has been one of the key therapeutic strategies employed in the treatment of skin cancer, especially in advanced stages of the disease. It could be also used as an adjuvant with other treatment modalities depending on the type of skin cancer. However, there are several shortfalls associated with the use of chemotherapy such as non-selectivity, tumour resistance, life-threatening toxicities, and the exorbitant cost of medicines. Furthermore, new drug discovery is a lengthy and costly process with minimal likelihood of success. Thus, drug repurposing (DR) has emerged as a new avenue where the drug approved formerly for the treatment of one disease can be used for the treatment of another disease like cancer. This approach is greatly beneficial over the de novo approach in terms of time and cost. Moreover, there is minimal risk of failure of repurposed therapeutics in clinical trials. There are a considerable number of studies that have reported on drugs repurposed for the treatment of skin cancer. Thus, the present manuscript offers a comprehensive overview of drugs that have been investigated as repurposing candidates for the efficient treatment of skin cancers mainly melanoma and its oncogenic subtypes, and non-melanoma. The prospects of repurposing phytochemicals against skin cancer are also discussed. Furthermore, repurposed drug delivery via topical route and repurposed drugs in clinical trials are briefed. Based on the findings from the reported studies discussed in this manuscript, drug repurposing emerges to be a promising approach and thus is expected to offer efficient treatment at a reasonable cost in devitalizing skin cancer.

Nuciferine Inhibits TMEM16A in Dietary Adjuvant Therapy for Lung Cancer

Lung cancer is a malignant tumor with the highest morbidity and mortality rates. Food therapy is a common adjuvant treatment for lung cancer due to its safety and painlessness. Developing new functional food and exploring novel drug targets is important for lung cancer adjuvant therapy. This study confirmed that the active ingredient nuciferine of the lotus leaf was a novel TMEM16A inhibitor by whole-cell patch clamp experiments and site-directed mutagenesis experiments. CCK8 assay, colony formation assay, wound healing assay, and Annexin-V assay were combined to prove that nuciferine inhibited the proliferation and migration of lung cancer cells and promoted cancer cell apoptosis by targeting TMEM16A. Moreover, the combination of nuciferine and cisplatin significantly enhanced the anti-cancer effect of cisplatin. In addition, the signal transduction pathway of nuciferine regulating LA795 cell proliferation, migration, and apoptosis was confirmed by western blot experiments. In vivo experiments showed that nuciferine was a safe and effective natural anti-cancer product for lung cancer. Tissue section pathological detection and pharmacokinetic experiments verified that intragastric administration of nuciferine significantly enhanced the cancer therapy effect of cisplatin and counteracted the toxicity of high concentrations of cisplatin. Therefore, nuciferine is an ideal functional food for adjuvant lung cancer treatment.

Modulating Boronic Ester Stability in Block Copolymer Micelles via the Neighbor Effect of Copolymerized Tertiary Amines for Controlled Release of Polyphenolic Drugs

The traceless and pH-sensitive properties of boronic esters are attractive for the synthesis of polymer-drug conjugates, but current platforms suffer from both low stability under physiologically relevant conditions and synthetically demanding optimization to tune drug release profiles. We hypothesized that the high catechol affinity and stability of Wulff-type boronic acids could be mimicked by copolymerization of phenyl boronic acid with a tertiary amine and subsequent micellization. This strategy yielded a versatile platform for the preparation of reversible polymer-drug conjugates, which more than doubled the oxidative stability of encapsulated polyphenolic drug cargo at physiologically relevant pH and enabled simple and incremental tuning of drug release kinetics. Moreover, we validated, with ¹⁹F NMR, that these copolymers exhibit uniquely high catechol affinity that could not be replicated by combinations of similarly functionalized small molecules. Overall, this report demonstrates that copolymerization of boronic acid and tertiary amine monomers is a powerful and modular approach to improving boronic ester chemistry for drug delivery applications.

Phytochemical-loaded liposomes for anticancer therapy: an updated review

The major obstacles observed in current chemotherapy are severe adverse effects, narrow therapeutic indexes and multidrug resistance. Anticancer phytochemicals are extracted and purified from natural plants, providing alternative therapeutic approaches with recognized biomedical benefits. However, poor bioavailability, high dose requirements and non-specific targeting have made those molecules less effective. To tackle those issues, liposomal nanovesicles for phytochemical delivery are taken into consideration for improving the therapeutic effectiveness by increasing transportation across cell barriers and conferring attractive cancer-specific targeting capabilities. In the present review, the liposomal approaches of anticancer phytochemicals are discussed, and recent advances in these formulations applied to cancer phytotherapy are further reviewed by an informed approach.

Electrospun Coaxial Fibers to Optimize the Release of Poorly Water-Soluble Drug

In a drug delivery system, the physicochemical properties of the polymeric matrix have a positive impact on the bioavailability of poorly water-soluble drugs. In this work, monolithic F1 fibers and coaxial F2 fibers were successfully prepared using polyvinylpyrrolidone as the main polymer matrix for drug loading and the poorly water-soluble curcumin (Cur) as a model drug. The hydrophobic poly (3-hydroxybutyric acid-co-3-hydroxyvaleric acid) (PHBV) was designed as a blank layer to change the hydrophilicity of the fiber and restrain the drug dissolution rate. The curved linear morphology without beads of F1 fibers and the straight linear morphology with few spindles of F2 fibers were characterized using field-emission environmental scanning electron microscopy. The amorphous forms of the drug and its good compatibility with polymeric matrix were verified by X-ray diffraction and attenuated total reflectance Fourier transformed infrared spectroscopy. Surface wettability and drug dissolution data showed that the weaker hydrophilicity F2 fibers (31.42° ± 3.07°) had 24 h for Cur dissolution, which was much longer than the better hydrophilic F1 fibers (15.31° ± 2.79°) that dissolved the drug in 4 h.

Celastrol inhibits the proliferation and induces apoptosis of colorectal cancer cells via downregulating NF-κB/COX-2 signaling pathways

BACKGROUND

Colorectal cancer (CRC) is the third-ranked malignant tumor in the world that contributes to the death of a major population of the world. Celastrol, a bioactive natural product isolated from the medicinal plant Tripterygium wilfordii Hook F, has been proved to be an effective anti-tumor inhibitor for multiple tumors.

OBJECTIVE

To reveal the therapeutic effect and underlying mechanisms of celastrol on CRC cells.

METHODS

CCK-8 and clonogenic assay were used to analyze the cell proliferation in CRC cells. Flow cytometry analysis was conducted to assess the cell cycle and cell apoptosis. Wound-healing and cell invasion assay were used to evaluate the migrating and invasion capability of CRC cells. The potential antitumor mechanism of celastrol was investigated by qPCR, western blot, and confocal immunofluorescence analyses.

RESULTS

Celastrol effectively inhibited CRC cell proliferation by activating caspase-dependent cell apoptosis and facilitating G1 cell cycle arrest in a dose-dependent manner, as well as cell migration and invasion by downregulating the MMP2 and MMP9. Mechanistic protein expression revealed that celastrol suppressed the expression of COX-2 by inhibiting the phosphorylation of NF-κB p65 and subsequently leading to cytoplasmic retention of p65 protein, thereby inhibiting its nuclear translocation and transcription activities.

CONCLUSION

These findings indicate that celastrol is an effective inhibitor for CRC, regulating the NF-κB/COX-2 pathway, leading to the inhibition of cell proliferation characterized by cell cycle arrest and caspase-dependent apoptosis, providing a potential alternative therapeutic agent for CRC patients.

Electrospun PVP-Core/PHBV-Shell Fibers to Eliminate Tailing Off for an Improved Sustained Release of Curcumin

Tailing off release in the sustained release of water-insoluble curcumin (Cur) is a significant challenge in the drug delivery system. As a novel solution, core-shell nanodrug containers have aroused many interests due to their potential improvement in drug-sustained release. In this work, a biodegradable polymer, poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), and hydrophilic polyvinylpyrrolidone (PVP) were exploited as drug delivery carriers by coaxial electrospinning, and the core-shell drug-loaded fibers exhibited improved sustained release of Cur. A cylindrical morphology and a clear core-shell structure were observed by scanning and transmission electron microscopies. The X-ray diffraction pattern and infrared spectroscopy revealed that Cur existed in amorphous form due to its good compatibility with PHBV and PVP. The in vitro drug release curves confirmed that the core-shell container manipulated Cur in a faster drug release process than that in the traditional PHBV monolithic container. The combination of the material and structure forms a novel nanodrug container with a better sustained release of water-insoluble Cur. This strategy is beneficial for exploiting more functional biomedical materials to improve the drug release behavior.

Status and Challenges of Plant-Anticancer Compounds in Cancer Treatment

Nowadays, cancer is one of the deadliest diseases in the world, which has been estimated to cause 9.9 million deaths in 2020. Conventional treatments for cancer commonly involve mono-chemotherapy or a combination of radiotherapy and mono-chemotherapy. However, the negative side effects of these approaches have been extensively reported and have prompted the search of new therapeutic drugs. In this context, scientific community started to look for innovative sources of anticancer compounds in natural sources, including traditional plants. Currently, numerous studies have evaluated the anticancer properties of natural compounds derived from plants, both in vitro and in vivo. In pre-clinical stages, some promising compounds could be mentioned, such as the sulforaphane or different phenolic compounds. On the other hand, some phytochemicals obtained positive results in clinical stages and were further approved for cancer treatment, such as vinca alkaloids or the paclitaxel. Nevertheless, these compounds are not exempt of limitations, such as low solubility, restricted effect on their own, negative side-effects, etc. This review aims to compile the information about the current phytochemicals used for cancer treatment and also promising candidates, main action mechanisms and also reported limitations. In this sense, some strategies to face the limitations have been considered, such as nano-based formulations to improve solubility or chemical modification to reduce toxicity. In conclusion, although more research is still necessary to develop more efficient and safe phytochemical drugs, more of these compounds might be used in future cancer therapies.