Multiple Molecular Mechanisms to Overcome Multidrug Resistance in Cancer by Natural Secondary Metabolites

A review of natural products and small-molecule therapeutics acting on central nervous system malignancies: Approaches for drug development, targeting pathways, clinical trials, and challenges

In 2021, the World Health Organization released the fifth edition of the central nervous system (CNS) tumor classification. This classification uses histopathology and molecular pathogenesis to group tumors into more biologically and molecularly defined entities. The prognosis of brain cancer, particularly malignant tumors, has remained poor worldwide, approximately 308,102 new cases of brain and other CNS tumors were diagnosed in the year 2020, with an estimated 251,329 deaths. The cost and time-consuming nature of studies to find new anticancer agents makes it necessary to have well-designed studies. In the present study, the pathways that can be targeted for drug development are discussed in detail. Some of the important cellular origins, signaling, and pathways involved in the efficacy of bioactive molecules against CNS tumorigenesis or progression, as well as prognosis and common approaches for treatment of different types of brain tumors, are reviewed. Moreover, different study tools, including cell lines, in vitro, in vivo, and clinical trial challenges, are discussed. In addition, in this article, natural products as one of the most important sources for finding new chemotherapeutics were reviewed and over 700 reported molecules with efficacy against CNS cancer cells are gathered and classified according to their structure. Based on the clinical trials that have been registered, very few of these natural or semi-synthetic derivatives have been studied in humans. The review can help researchers understand the involved mechanisms and design new goal-oriented studies for drug development against CNS malignancies.

Exploring therapeutic potential of Rutin by investigating its cyclin-dependent kinase 6 inhibitory activity and binding affinity

Cyclin-dependent kinase 6 (CDK6) participates in numerous signalling pathways and regulates various physiological processes. Due to its unique structural features and promising therapeutic potential, CDK6 has emerged as a drug target for designing and developing small-molecule inhibitors for anti-cancer therapeutics and other CDK6-associated diseases. The current study evaluates binding affinity and the inhibitory potential of rutin for CDK6 to develop a proof of concept for rutin as a potent CDK6 inhibitor. Molecular docking and 200 ns all-atom simulations reveal that rutin binds to the active site pocket of CDK6, forming interactions with key residues of the binding pocket. In addition, the CDK6-rutin complex remains stable throughout the simulation trajectory. A high binding constant (Ka = 7.6 × 105M-1) indicates that rutin has a strong affinity for CDK6. Isothermal titration calorimetry has further validated a strong binding of rutin with CDK6 and its spontaneous nature. The kinase activity of CDK6 is significantly inhibited by rutin with an IC50 value of 3.10 μM. Our findings highlight the significant role of rutin in developing potential therapeutic molecules to manage cancer and CDK6-associated diseases via therapeutic targeting of CDK6.

Investigating the Effect of Satureja khuzestanica Essential oil on MDR1 Gene Expression in Leishmania major

BACKGROUND

Cutaneous leishmaniasis is among the neglected diseases in the world. Pentavalent antimonial compounds are considered the first-line treatment for this disease. However, using alternative natural products has received great attention due to the side effects of chemical drugs and drug resistance of the Leishmania parasite. The present study aims to investigate the effect of Satureja khuzestanica essential oil (SKEO) on MDR1 gene expression.

METHODS

In this study, standard strains of Leishmania major promastigotes were exposed to 5, 10, 15, and 20 µg/ml of SKEO. MDR1 gene expression of parasites exposed to essential oil was evaluated using real-time PCR. GAPDH was employed as the housekeeping gene for internal control.

RESULTS

Despite the increase, no statistically significant difference was observed in the relative expression of the MDR1 gene between the control group and the groups containing 5, 10, and 20 µg/ml of SKEO (P > 0.05). The relative expression of the MDR1 gene significantly increased in the group containing 15 μg/ml of essential oil compared to the control one (P < 0.05).

CONCLUSION

This study showed that the use of essential oil of Satureja khuzestanica plant can have an increasing effect on the expression of MDR1 gene of Leishmania promastigotes, which is the best case if Satureja khuzestanica essential oil reduces the expression of MDR1 gene. So it seems that the use of essential oil of Satoria plant is effective in controlling Leishmania parasite, but its concentrations induce drug resistance. As a result, concentrations of essential oil should be used that have a controlling effect on the growth and proliferation of Leishmania parasite and also have the least effect on the induction of MDR1 gene expression.

Pentacyclic triterpenoids from the stem of Grewia bracteata Roth demonstrate promising inhibition on tumour cells

Grewia bracteata Roth stem was investigated for its anticancer potential for the first time. Initially, polarity-guided extracts from three solvents were screened on HeLa, HCT- 116 and MCF-7 tumours cells. The results revealed that ethyl acetate extract (GSE) significantly (p < 0.05) inhibited HeLa, HCT- 116 and MCF-7 cells with respective IC50 values of 30.58, 14.26 and 22.91 µg/mL. GSE inhibited HCT-116 cells with 6- and 21-folds higher than hexane (GSN) and methanol (GSM) extracts, respectively. Hence, column chromatography of GSE was performed and fractionated to 18 fractions. The obtained fractions were further tested on HCT-116 cells. Amongst, the fractions HF6 and DF1 were active with the respective IC50 values of 25.35 and 31.28, µg/mL (p < 0.05). These active fractions were profiled using H1-NMR, C13-NMR and LC-MS/MS analysis, and found the presence of pentacyclic triterpenoids like betulin diacetate and ursolic acid.

Doxorubicin-sanguinarine nanoparticles: formulation and evaluation of breast cancer cell apoptosis and cell cycle

BACKGROUND

Therapeutic resistance fails cancer treatment. Drug-nanoparticle combinations overcome resistance. Sanguinarine-conjugated nanoparticles may boost sanguinarine's anticancer effects.

METHODS

Sanguinarine, HPMC-NPs, and doxorubicin were tested on Adriamycin-resistant MCF-7/ADR breast cancer cells, parent-sensitive MCF-7, and MCR-5 normal cells (DX).

RESULTS

Regular distribution, 156 nm diameter, <1 μm average size, 100% intensity-SN is therapeutic. Furthermore, the obtained NPs showed PDI = 0.145, zeta-potential=-37.6, and EE%=90.5%. DX sensitized MCF-7 cells (IC50 = 1.4 μM) more than MCF-7/ADR cells (IC50 = 27 μM) with RR = 19.3. SA and SN were more toxic to MCF-7/ADR cells (overexpressed with P-gp) than their sensitive parent MCF-7 cells (IC50 = 4 μM, RR = 0.6 and 0.6 μM, RR = 0.7). MCR-5 normal lung cells were more resistant to SA (IC50 = 7.2 μM) and SN (IC50 = 1.6 μM) with a selection index > 2. Synergistic cytotoxic interactions reduced the IC50 from 27 μM to 1.6 (CI = 0.1) and 0.9 (CI = 0.4) after DX and nontoxic dosages (IC20) of SA and SN. DS and SN killed 27.1% and 39.4% more cells than DX (7.7%), SA (4.9%), SN (5.5%), or untreated control (0.3%). DS and DSN lowered CCND1 and survival in MCF-7/ADR cells while raising p21 and Casp3 gene and protein expression.

CONCLUSIONS

Cellular and molecular studies suggested adjuvant chemosensitizers SA and SN to reverse MDR in breast cancer cells.

Synthesis and Anticancer Activity of A-Ring-Modified Derivatives of Dihydrobetulin

Multidrug resistance (MDR) is a common phenomenon in clinical oncology, whereby cancer cells become resistant to chemotherapeutic drugs. A common MDR mechanism is the overexpression of ATP-binding cassette efflux transporters in cancer cells, with P-glycoprotein (P-gp) being one of them. New 3,4-seco-lupane triterpenoids, and the products of their intramolecular cyclization with the removed 4,4-gem-dimethyl group, were synthesized by the selective transformations of the A-ring of dihydrobetulin. Among the semi-synthetic derivatives, the MT-assay-enabled methyl ketone 31 (MK), exhibiting the highest cytotoxicity (0.7-16.6 µM) against nine human cancer cell lines, including P-gp overexpressing subclone HBL-100/Dox, is identified. In silico, MK has been classified as a potential P-gp-inhibitor; however, the Rhodamine 123 efflux test, and the combined use of P-gp-inhibitor verapamil with MK in vitro, showed the latter to be neither an inhibitor nor a substrate of P-gp. As the studies have shown, the cytotoxic effect of MK against HBL-100/Dox cells is, arguably, induced through the activation of the ROS-mediated mitochondrial pathway, as evidenced by the positive Annexin V-FITC staining of apoptotic cells, the cell cycle arrest in the G0/G1 phase, mitochondrial dysfunction, cytochrome c release, and the activation of caspase-9 and -3.

Importance of ABC Transporters in the Survival of Parasitic Nematodes and the Prospect for the Development of Novel Control Strategies

ABC transporters, a family of ATP-dependent transmembrane proteins, are responsible for the active transport of a wide range of molecules across cell membranes, including drugs, toxins, and nutrients. Nematodes possess a great diversity of ABC transporters; however, only P-glycoproteins have been well-characterized compared to other classes. The ABC transport proteins have been implicated in developing resistance to various classes of anthelmintic drugs in parasitic nematodes; their role in plant and human parasitic nematodes still needs further investigation. Therefore, ABC transport proteins offer a potential opportunity to develop nematode control strategies. Multidrug resistance inhibitors are becoming more attractive for controlling nematodes due to their potential to increase drug efficacy in two ways: (i) by limiting drug efflux from nematodes, thereby increasing the amount of drug that reaches its target site, and (ii) by reducing drug excretion by host animals, thereby enhancing drug bioavailability. This article reviews the role of ABC transporters in the survival of parasitic nematodes, including the genes involved, their regulation and physiological roles, as well as recent developments in their characterization. It also discusses the association of ABC transporters with anthelmintic resistance and the possibility of targeting them with next-generation inhibitors or nutraceuticals (e.g., polyphenols) to control parasitic infections.

Herb-drug interactions between Panax notoginseng or its biologically active compounds and therapeutic drugs: A comprehensive pharmacodynamic and pharmacokinetic review

ETHNOPHARMACOLOGICAL RELEVANCE

Herbs, along with the use of herb-drug interactions (HDIs) to combat diseases, are increasing in popularity worldwide. HDIs have two effects: favorable interactions that tend to improve therapeutic outcomes and/or minimize the toxic effects of drugs, and unfavorable interactions aggravating the condition of patients. Panax notoginseng (Burk.) F.H. Chen is a medicinal plant that has long been commonly used in traditional Chinese medicine to reduce swelling, relieve pain, clear blood stasis, and stop bleeding. Numerous studies have demonstrated the existence of intricate pharmacodynamic (PD) and pharmacokinetic (PK) interactions between P. notoginseng and conventional drugs. However, these HDIs have not been systematically summarized.

AIM OF THE REVIEW

To collect the available literature on the combined applications of P. notoginseng and drugs published from 2005 to 2022 and summarize the molecular mechanisms of interactions to circumvent the potential risks of combination therapy.

MATERIALS AND METHODS

This work was conducted by searching PubMed, Scopus, Web of Science, and CNKI databases. The search terms included "notoginseng", "Sanqi", "drug interaction," "synergy/synergistic", "combination/combine", "enzyme", "CYP", and "transporter".

RESULTS

P. notoginseng and its bioactive ingredients interact synergistically with numerous drugs, including anticancer, antiplatelet, and antimicrobial agents, to surmount drug resistance and side effects. This review elaborates on the molecular mechanisms of the PD processed involved. P. notoginseng shapes the PK processes of the absorption, distribution, metabolism, and excretion of other drugs by regulating metabolic enzymes and transporters, mainly cytochrome P450 enzymes and P-glycoprotein. This effect is a red flag for drugs with a narrow therapeutic window. Notably, amphipathic saponins in P. notoginseng act as auxiliary materials in drug delivery systems to enhance drug solubility and absorption and represent a new entry point for studying interactions.

CONCLUSION

This article provides a comprehensive overview of HDIs by analyzing the results of the in vivo and in vitro studies on P. notoginseng and its bioactive components. The knowledge presented here offers a scientific guideline for investigating the clinical importance of combination therapies. Physicians and patients need information on possible interactions between P. notoginseng and other drugs, and this review can help them make scientific predictions regarding the consequences of combination treatments.

The Molecular Mechanisms of Oleanane Aldehyde-β-enone Cytotoxicity against Doxorubicin-Resistant Cancer Cells

Oleanane aldehyde-β-enone (OA), being the semi-synthetic derivative of the triterpenoid betulin, effectively inhibits the proliferation of HBL-100 and K562 cancer cells (IC50 0.47–0.53 µM), as well as the proliferation of their resistant subclones with high P-gp expression HBL-100/Dox, K562/i-S9 and K562/i-S9_Dox (IC50 0.45−1.24 µM). A molecular docking study, rhodamine efflux test, synergistic test with Dox, and ABC transporter gene expression were used to investigate the ability of OA to act as a P-gp substrate or inhibitor against Dox-resistant cells. We noted a trend toward a decrease in ABCB1, ABCC1 and ABCG2 expression in HBL-100 cells treated with OA. The in silico and in vitro methods suggested that OA is neither a direct inhibitor nor a competitive substrate of P-gp in overexpressing P-gp cancer cells. Thus, OA is able to overcome cellular resistance and can accumulate in Dox-resistant cells to realize toxic effects. The set of experiments suggested that OA toxic action can be attributed to activating intrinsic/extrinsic or only intrinsic apoptosis pathways in Dox-sensitive and Dox-resistant cancer cells, respectively. The cytotoxicity of OA in resistant cells is likely mediated by a mitochondrial cell death pathway, as demonstrated by positive staining with Annexin V–FITC, an increasing number of cells in the subG0/G1 phase, reactive oxygen species generation, mitochondrial dysfunction, cytochrome c migration and caspases-9,-6 activation.

In Vitro Anticancer and Antibacterial Activities of the Essential Oil of Forsskal’s Basil Growing in Extreme Environmental Conditions

Many species belonging to the genus Ocimum are used for aromatic, medicinal, and cosmetic purposes. The essential oil (OFEO) obtained by hydrodistillation of the flowering aerial parts of Forsskal’s Basil “Ocimum forskolei Benth” growing in extreme environmental conditions in Mecca Region, Saudi Arabia was analyzed by GC-MS. The main constituents were phenylpropanoids (methyl eugenol 55.65% and eugenol 11.66%), monoterpene (linalool 9.75%), and sesquiterpenes (germacrene D 3.72% and β-caryophyllene 2.57%). The OFEO was tested against MCF7, HT29, and HCT116 cancer cells and compared with normal fibroblast cells (MRC5). The MTT assay showed that HCT116 was more sensitive to OFEO (IC50 5.34 μg/mL), which reduced the number of HCT116 colonies at 6 μg/mL, while causing complete colony death at 12 and 24 μg/mL. Western Blotting and qRT-PCR were used to evaluate the level change of different proteins with respect to GAPDH. OFEO upregulated the apoptotic protein (caspase 3), and downregulated the cell proliferation proteins (AKT and pAKT), cell cycle arrest (PCNA, Cyclin D1), and the anti-apoptotic Bcl2 proteins. OFEO was also tested against reference strains of Gram-negative and Gram-positive bacteria including Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa, and Staphylococcus aureus by using the well-diffusion and assessing their MICs, which ranged from 250 to 500 μg/mL.

CRISPR/Cas9 as precision and high-throughput genetic engineering tools in gastrointestinal cancer research and therapy

Gastrointestinal cancer (GI) is one of the most serious and health-threatening diseases worldwide. Many countries have encountered an escalating prevalence of shock. Therefore, there is a pressing need to clarify the molecular pathogenesis of these cancers. The use of high-throughput technologies that allow the precise and simultaneous investigation of thousands of genes, proteins, and metabolites is a critical step in disease diagnosis and cure. Recent innovations have provided easy and reliable methods for genome investigation, including TALENs, ZFNs, and the CRISPR/Cas9 (clustered regularly interspaced palindromic repeats system). Among these, CRISPR/Cas9 has been revolutionary tool in genetic research. Recent years were prosperous years for CRISPR by the discovery of novel Cas enzymes, the Nobel Prize, and the development of critical clinical trials. This technology utilizes comprehensive information on genes associated with tumor development, provides high-throughput libraries for tumor therapy by developing screening platforms, and generates rapid tools for cancer therapy. This review discusses the various applications of CRISPR/Cas9 in genome editing, with a particular focus on genome manipulation, including infection-related genes, RNAi targets, pooled library screening for identification of unknown driver mutations, and molecular targets for gastrointestinal cancer modeling. Finally, it provides an overview of CRISPR/Cas9 clinical trials, as well as the challenges associated with its use.

Why Do Dietary Flavonoids Have a Promising Effect as Enhancers of Anthracyclines? Hydroxyl Substituents, Bioavailability and Biological Activity

Anthracyclines currently play a key role in the treatment of many cancers, but the limiting factor of their use is the widespread phenomenon of drug resistance and untargeted toxicity. Flavonoids have pleiotropic, beneficial effects on human health that, apart from antioxidant activity, are currently considered small molecules-starting structures for drug development and enhancers of conventional therapeutics. This paper is a review of the current and most important data on the participation of a selected series of flavonoids: chrysin, apigenin, kaempferol, quercetin and myricetin, which differ in the presence of an additional hydroxyl group, in the formation of a synergistic effect with anthracycline antibiotics. The review includes a characterization of the mechanism of action of flavonoids, as well as insight into the physicochemical parameters determining their bioavailability in vitro. The crosstalk between flavonoids and the molecular activity of anthracyclines discussed in the article covers the most important common areas of action, such as (1) disruption of DNA integrity (genotoxic effect), (2) modulation of antioxidant response pathways, and (3) inhibition of the activity of membrane proteins responsible for the active transport of drugs and xenobiotics. The increase in knowledge about the relationship between the molecular structure of flavonoids and their biological effect makes it possible to more effectively search for derivatives with a synergistic effect with anthracyclines and to develop better therapeutic strategies in the treatment of cancer.

Protection Against Drug-Induced Liver Injuries Through Nutraceuticals via Amelioration of Nrf-2 Signaling

Hepatotoxicity caused by the overdose of various medications is a leading cause of drug-induced liver injury. Overdose of drugs causes hepatocellular necrosis. Nutraceuticals are reported to prevent drug-induced liver failure. The present article aims to review the protection provided by various medicinal plants against hepatotoxic drugs. Ayurveda is considered a conventional restorative arrangement in India. It is consistently used for ages and is still used today to cure drug-induced hepatotoxicity by focusing on antioxidant stress response pathways such as the nuclear factor erythroid-2 (Nrf-2) antioxidant response element signaling pathway. Nrf-2 is a key transcription factor that entangles Kelch-like ECH-associating protein 1, a protein found in the cell cytoplasm. Some antioxidant enzymes, such as gamma glycine cysteine ligase (γ-GCL) and heme oxygenase-1 (HO-1), are expressed in Nrf-2 targeted genes. Their expression, in turn, decreases the stimulation of hepatic macrophages and induces the messenger RNA (mRNA) articulation of proinflammatory factors including tumor necrosis factor α. This review will cover various medicinal plants from a mechanistic view and how they stimulate and interact with Nrf-2, the master regulator of the antioxidant response to counterbalance oxidative stress. Interestingly, therapeutic plants have become popular in the medical sector due to safer yet effective supplementation for the prevention and treatment of new human diseases. The contemporary study is expected to collect information on a variety of therapeutic traditional herbs that have been studied in the context of drug-induced liver toxicity, as nutraceuticals are the most effective treatments for oxidative stress-induced hepatotoxicity. They are less genotoxic, have a lower cost, and are readily available. Together, nutraceuticals exert protective effects against drug-induced hepatotoxicity through the inhibition of oxidative stress, inflammation, and apoptosis. Its mechanism(s) are considered to be associated with the γ-GCL/HO-1 and Nrf-2 signaling pathways. KEY TEACHING POINTSThe liver is the most significant vital organ that carries out metabolic activities of the body such as the synthesis of glycogen, the formation of triglycerides and cholesterol, as well as the formation of bile.Acute liver failure is caused by the consumption of certain drugs; drug-induced liver injury is the major condition.The chemopreventive activity of nutraceuticals may be related to oxidative stress reduction and attenuation of biosynthetic processes involved in hepatic injury via amelioration of the nuclear factor erythroid-2 (Nrf-2) signaling pathway.Nrf-2 is a key transcription factor that is found in the cell cytoplasm resulting in the expression of various genes such as gamma glycine cysteine ligase and heme oxygenase-1.Nutraceutical-rich phytochemicals possess high antioxidant activity, which helps in the prevention of hepatic injury.

Multidrug Resistance of Cancer Cells and the Vital Role of P-Glycoprotein

P-glycoprotein (P-gp) is a major factor in the multidrug resistance phenotype in cancer cells. P-gp is a protein that regulates the ATP-dependent efflux of a wide range of anticancer medicines and confers resistance. Due to its wide specificity, several attempts have been made to block the action of P-gp to restore the efficacy of anticancer drugs. The major goal has been to create molecules that either compete with anticancer medicines for transport or function as a direct P-gp inhibitor. Despite significant in vitro success, there are presently no drugs available in the clinic that can "block" P-gp-mediated resistance. Toxicity, unfavourable pharmacological interactions, and a variety of pharmacokinetic difficulties might all be the reason for the failure. On the other hand, P-gp has a significant effect in the body. It protects the vital organs from the entry of foreign bodies and other toxic chemicals. Hence, the inhibitors of P-gp should not hinder its action in the normal cells. To develop an effective inhibitor of P-gp, thorough background knowledge is needed in this field. The main aim of this review article was to set forth the merits and demerits of the action of P-gp on cancer cells as well as on normal cells. The influence of P-gp on cancer drug delivery and the contribution of P-gp to activating drug resistance were also mentioned.

Chemosensitization Effect of Seabuckthorn (Hippophae rhamnoides L.) Pulp Oil via Autophagy and Senescence in NSCLC Cells

The research has demonstrated a synergistic anticancer effect of Seabuckthorn pulp oil (SBO) and the standard chemotherapy regimen Docetaxel (DTX) against two non-small cell lung cancer (NSCLC) cell lines: A549 and H23. The synergizing effect of an SBO and DTX combination was detected utilizing SRB assay and combination index (CI) approaches. Flow cytometry was carried out using fluorescent probes to measure cell cycle analysis by DNA content and reactive oxygen species (ROS) generation. Further, we demonstrated that the synergistic anticancer activity of SBO merged with DTX was achieved by caspase-independent autophagy and senescence induction. These changes were concomitant with increased generation of ROS production and microtubule-associated protein 1 light chain 3 (LC3) protein expression, G1-phase arrest, and enhanced senescence-associated β-galactosidase staining activity. Our data also demonstrated that SBO or DTX treatment groups solely upregulated the phosphorylation of ERK, which coincided with the induction of autophagy vacuoles and was functionally associated with ROS activation. Moreover, endogenous LC3 puncta staining was performed and monitored by confocal microscopy. Overall, these results suggest new mechanisms for the antitumor activity of SBO co-treated with DTX through triggering autophagic cell death and senescence against cancer cells as a result of sustained ERK phosphorylation and intracellular ROS production in NSCLC. In addition, we also highlight SBO as an alternative therapeutic option or adjunct therapeutic strategy in combination with chemotherapeutic agents in lung cancer therapy management.

Therapeutic implication of carbon monoxide in drug resistant cancers

Drug resistance is the major obstacle that undermines effective cancer treatment. Recently, the application of gas signaling molecules, e.g., carbon monoxide (CO), in overcoming drug resistance has gained significant attention. Growing evidence showed that CO could inhibit mitochondria respiratory effect and glycolysis, two major ATP production pathways in cancer cells, and suppress angiogenesis and inhibit the activity of cystathionine β-synthase that is important in regulating cancer cells homeostasis, leading to synergistic effects when combined with cisplatin, doxorubicin, or phototherapy, etc. in certain resistant cancer cells. In the current review, we attempted to have a summary of these research conducted in the past decade using CO in treating drug resistant cancers, and have a detailed interpretation of the underlying mechanisms. The critical challenges will be discussed and potential solutions will also be provided. The information collected in this work will hopefully evoke more effects in using CO for the treatment of drug resistant cancers.

A novel, dual action chimera comprising DNA methylating agent and near-IR xanthene-cyanine photosensitizer for combined anticancer therapy

A facile synthesis, biological evaluation and photodynamic properties of novel activatable anticancer molecular hybrids (chimeras) Ch and I-Ch are described. The chimeras consist of DNA methylating methyl triazene moiety and fluorogenic xanthene-cyanine (XCy) or iodinated xanthene-cyanine (I-XCy) photosensitizer. These two anticancer core structures are bound by means of a self-immolative 4-aminobenzyl alcohol linker. The hydrolytic cleavage of the carbamate protecting group promotes activation of both DNA methylating monomethyl triazene and phototoxic xanthene-cyanine dye providing, in addition, a near-IR emission signal for detection of the drug activation events. Preliminary antiproliferative assay demonstrates that the developed chimeras exhibit higher antitumor activity in the breast cancer cell line upon near-IR light irradiation compared to their structural constituents, xanthene-cyanine photosensitizer and monomethyl triazene substance.

Aptamers: an emerging navigation tool of therapeutic agents for targeted cancer therapy

Chemotherapeutic agents have been used for the treatment of numerous cancers, but due to poor selectivity and severe systemic side effects, their clinical application is limited. Single-stranded DNA (ssDNA) or RNA aptamers could conjugate with highly toxic chemotherapy drugs, toxins, therapeutic RNAs or other molecules as novel aptamer-drug conjugates (ApDCs), which are capable of significantly improving the therapeutic efficacy and reducing the systemic toxicity of drugs and have great potential in clinics for targeted cancer therapy. In this review, we have comprehensively discussed and summarized the current advances in the screening approaches of aptamers for specific cancer biomarker targeting and development of the aptamer-drug conjugate strategy for targeted drug delivery. Moreover, considering the huge progress in artificial intelligence (AI) for protein and RNA structure predictions, automatic design of aptamers using deep/machine learning techniques could be a powerful approach for rapid and precise construction of biopharmaceutics (i.e., ApDCs) for application in cancer targeted therapy.

Aster glehni F. Schmidt Extract Modulates the Activities of HMG-CoA Reductase and Fatty Acid Synthase

Aster glehni F. Schmidt (AG), is a natural product known to have anti-obesity effects, but the mechanism underlying these effects is not well documented. We hypothesized that AG may have inhibitory effects on enzymes related to lipid accumulation. Herein, AG fractions were tested against HMG-CoA reductase (HMGR) and fatty acid synthase (FAS), two important enzymes involved in cholesterol and fatty acid synthesis, respectively. We found that dicaffeoylquinic acid (DCQA) methyl esters present in AG are largely responsible for the inhibition of HMGR and FAS. Since free DCQA is a major form present in AG, we demonstrated that a simple methylation of the AG extract could increase the overall inhibitory effects against those enzymes. Through this simple process, we were able to increase the inhibitory effect by 150%. We believe that our processed AG effectively modulates the HMGR and FAS activities, providing promising therapeutic potential for cholesterol- and lipid-lowering effects.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

A Polyphenol-Rich Extract of Olive Mill Wastewater Enhances Cancer Chemotherapy Effects, While Mitigating Cardiac Toxicity

Cardiovascular toxicity remains one of the most adverse side effects in cancer patients receiving chemotherapy. Extra-virgin olive oil (EVOO) is rich in cancer preventive polyphenols endowed with anti-inflammatory, anti-oxidant activities which could exert protective effects on heart cells. One very interesting derivative of EVOO preparation is represented by purified extracts from olive mill waste waters (OMWW) rich in polyphenols. Here, we have investigated the anti-cancer activity of a OMWW preparation, named A009, when combined with chemotherapeutics, as well as its potential cardioprotective activities. Mice bearing prostate cancer (PCa) xenografts were treated with cisplatin, alone or in combination with A009. In an in vivo model, we found synergisms of A009 and cisplatin in reduction of prostate cancer tumor weight. Hearts of mice were analyzed, and the mitochondria were studied by transmission electron microscopy. The hearts of mice co-treated with A009 extracts along with cisplatin had reduced mitochondria damage compared to the those treated with chemotherapy alone, indicating a cardioprotective role. To confirm the in vivo results, tumor cell lines and rat cardiomyocytes were treated with cisplatin in vitro, with and without A009. Another frequently used chemotherapeutic agent 5-fluorouracil (5-FU), was also tested in this assay, observing a similar effect. In vitro, the combination of A009 with cisplatin or 5-FU was effective in decreasing prostate and colon cancer cell growth, while it did not further reduce growth of rat cardiomyocytes also treated with cisplatin or 5-FU. A009 cardioprotective effects towards side effects caused by 5-FU chemotherapy were further investigated, using cardiomyocytes freshly isolated from mice pups. A009 mitigated toxicity of 5-FU on primary cultures of mouse cardiomyocytes. Our study demonstrates that the polyphenol rich purified A009 extracts enhance the effect of chemotherapy in vitro and in vivo, but mitigates chemotherpy adverse effects on heart and on isolated cardiomyocytes. Olive mill waste water extracts could therefore represent a potential candidate for cardiovascular prevention in patients undergoing cancer chemotherapy.