Role of phloretin as a sensitizer to TRAIL‑induced apoptosis in colon cancer

Combination treatment with Phloretin enhances the anti-tumor efficacy of radiotherapy in lung cancer models

INTRODUCTION

Phloretin (Ph), an apple polyphenol, has been shown to possess anti-tumor effects. This study aimed to investigate the anti-tumor effects of the combination of Ph and radiotherapy on lung cancer.

METHODS

The proliferative rate of Lewis lung carcinoma (LLC) cells treated with Ph was evaluated using the MTT assay. The radiosensitization effect of Ph was assessed using the clone formation assay. Additionally, the anti-tumor and radiosensitization effects of Ph were explored in LLC xenografts in mice.

RESULTS

Ph inhibited the proliferation of LLC cells in a time- and dose-dependent manner (p < 0.05). Moreover, the combination of Ph with radiotherapy significantly inhibited LLC cell colony formation (p < 0.05). In vivo studies demonstrated that the combination of Ph with radiotherapy significantly inhibited tumor growth, achieving a tumor inhibition rate of 74.44% compared to the control group (p < 0.01). This combination also prolonged the median survival times of mice by 31 days compared to the control group (p < 0.01), reduced tumor glucose uptake, promoted tumor cell apoptosis, and suppressed tumor cell proliferation.

CONCLUSION

This study suggests that the combination of Ph with radiotherapy exhibits promising activity against lung cancer, potentially through mechanisms including inhibition of glucose transport and promotion of apoptosis. These findings may provide a new therapeutic strategy for improving lung cancer treatment.

Bryophyllum pinnatum Induces p53-Dependent Apoptosis of Colorectal Cancer Cells via Increased Intracellular ROS and G2/M Cell-Cycle Arrest In Vitro and Validated in Silico by Molecular Docking

Chemotherapy, radiotherapy and surgical treatments of cancer having several limitations and toxic side-effects, have led researchers to focus towards development of alternative natural plant-based therapeutics that can reduce disease severity. The present research work is mainly focussed towards identifying molecular mechanisms of apoptosis of colorectal cancer cells (HCT116) by perennial herb Bryophyllum pinnatum leaf-extract via both in vitro experimentations and in silico analysis. B. pinnatum leaf extract induced highest cytotoxicity at lowest dose (IC50:0.01 mg/mL) against HCT116 cells with 49.5% (p < 0.0001) cellular death, in comparison to other cancer cell lines. It has arrested HCT116 cell populations at G2/M cell-cycle phase and led to 10 folds (p < 0.0001) and 5.5 folds (p < 0.0001) increased intracellular ROS production in treated groups. ROS production might have led to significant 34.23% and 21.03% (p < 0.0001) apoptosis in treated cells, proved in vitro and in silico, with significant upregulation of p53 (p < 0.0001), BAX (p = 0.0252), CASPASE3 (p < 0.0001) and downregulation of BCL2 (p = 0.0058), leading to increased nuclear p53 (p = 0.0002) accumulation in treated cells, suggesting that the leaf-extract might have induced p53-dependent apoptosis of colorectal cancer cells. The phyto-extract also possess significant gene-modulatory potential as evident from qRT-PCR analysis of oncogenes and tumor suppressor genes. Leaf's bioactive phyto-constituents were elucidated by GC-MS and HPLC-ESI/MS analysis. In silico STITCH analysis provided significant network interactions between these bioactive phyto-compounds and studied proteins. Further Molecular Docking studies revealed strong binding between such docked complexes. Also, predicted major bioactive phyto-constituents of B. pinnatum leaf-extract such as Quercetin, Morin and β-Sitosterol have induced significant (p < 0.0001) apoptosis and increased intracellular ROS, validating their in silico interactions with studied proteins of HCT116 cells. All these studies together demonstrated ability of B. pinnatum to be used as a suitable natural phyto-therapeutic agent for development of chemo-preventive medications against colorectal cancer.

Low extracellular pH enhances TRAIL-induced apoptosis by downregulating Mcl-1 expression

We previously reported that low extracellular pH promotes tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis through the mitochondria-mediated caspase signal transduction pathway. In this study, we further investigated the mechanism of low extracellular pH on TRAIL-induced apoptosis. When human colorectal carcinoma HCT116 cells were treated with TRAIL for 4 h, significant cytotoxicity was observed at pH 6.3, while cytotoxic effects were notably reduced at pH 7.2. These findings suggest that TRAIL's cytotoxic effects on human colorectal cancer cells are enhanced in low pH environments following TRAIL treatment. Similar results were observed in human pancreatic adenocarcinoma BxPC-3 cells. Interestingly, TRAIL was found to downregulate the levels of anti-apoptotic proteins, such as Mcl-1. This was confirmed by the knock-in (KI) of an Mcl-1 phosphorylation site mutant in HCT116 cells, which blocked TRAIL-induced Mcl-1 downregulation and the subsequent apoptotic response. These results indicate that Mcl-1 mediates TRAIL resistance in the Mcl-1 KI cells. Additionally, our results revealed that TRAIL significantly induced JNK phosphorylation in HCT116 cells, suggesting the involvement of JNK in TRAIL-induced cell death in colorectal cancer cells. Our findings demonstrate that low extracellular pH enhances TRAIL-induced cytotoxicity, particularly at pH 6.3 and 6.6. Moreover, the anti-apoptotic Bcl-2 family member Mcl-1 is an important target of TRAIL in colorectal carcinoma HCT116 cells under different low pH conditions. TRAIL triggered a rapid decline in Mcl-1, suggesting that Mcl-1 downregulation is crucial for TRAIL-induced apoptosis.

A deep dive into the orchard of health: Exploring the anti-cancer and anti-aging potential of apple polyphenols

Apples, a ubiquitous and beloved fruit, harbor a treasure trove of bioactive compounds, with apple polyphenols (APs) taking center stage. This review delves into the latest scientific advancements illuminating the anti-cancer and anti-aging properties of APs. We dissect the intricate mechanisms by which APs combat cancer initiation, progression, and metastasis, highlighting their prowess in inducing apoptosis, inhibiting angiogenesis, and modulating cell signaling pathways. Furthermore, we explore the multifaceted ways APs combat aging, including their potent antioxidant and anti-inflammatory actions, DNA protective effects, and ability to modulate cellular processes like autophagy and metabolism. This comprehensive review underscores the therapeutic promise of APs in promoting healthy aging and combating age-related diseases like cancer.

Phloretin inhibits transmissible gastroenteritis virus proliferation via multiple mechanisms

Transmissible gastroenteritis virus (TGEV), an enteropathogenic coronavirus, has caused huge economic losses to the pig industry, with 100% mortality in piglets aged 2 weeks and intestinal injury in pigs of other ages. However, there is still a shortage of safe and effective anti-TGEV drugs in clinics. In this study, phloretin, a naturally occurring dihydrochalcone glycoside, was identified as a potent antagonist of TGEV. Specifically, we found phloretin effectively inhibited TGEV proliferation in PK-15 cells, dose-dependently reducing the expression of TGEV N protein, mRNA, and virus titer. The anti-TGEV activity of phloretin was furthermore refined to target the internalization and replication stages. Moreover, we also found that phloretin could decrease the expression levels of proinflammatory cytokines induced by TGEV infection. In addition, we expanded the potential key targets associated with the anti-TGEV effect of phloretin to AR, CDK2, INS, ESR1, ESR2, EGFR, PGR, PPARG, PRKACA, and MAPK14 with the help of network pharmacology and molecular docking techniques. Furthermore, resistant viruses have been selected by culturing TGEV with increasing concentrations of phloretin. Resistance mutations were reproducibly mapped to the residue (S242) of main protease (Mpro). Molecular docking analysis showed that the mutation (S242F) significantly disrupted phloretin binding to Mpro, suggesting Mpro might be a potent target of phloretin. In summary, our findings indicate that phloretin is a promising drug candidate for combating TGEV, which may be helpful for developing pharmacotherapies for TGEV and other coronavirus infections.

Impact of the crystal size of crystalline active pharmaceutical compounds on loading into microneedles

Microneedle (MN) technology offers a promising platform for the delivery of a wide variety of active pharmaceutical compounds into and/or through the skin. Yet, the low loading capacity of MNs limits their clinical translation. The solid state of loaded compounds, crystallinity versus amorphousness and crystal size of the former, could greatly affect their loading. Here, we investigated the effect of the crystal size of crystalline compounds on their loading into dissolving MNs, prepared using the solvent-casting technique. A model crystalline compound was subjected to crystal size reduction via wet bead milling and loaded into dissolving MNs. A range of crystal sizes, from micro to nano, was obtained via different milling periods. The obtained crystals were characterized for their size, morphology, and sedimentation behavior. Besides, their content, solid state inside the MNs, and impact on the MN mechanical strength were assessed. The crystals exhibited size-dependent sedimentation, which dramatically affected their loading inside the MNs. However, crystal size and sedimentation demonstrated a negligible effect on the mechanical strength and sharpness of the needles, hence no anticipated impact on the MNs' drug delivery efficiency. The elucidation of the correlation between the crystal size and MN loading opens new potentials to address a major drawback in MN technology.

Greasing the Wheels of Pharmacotherapy for Colorectal Cancer: the Role of Natural Polyphenols

PURPOSE OF REVIEW

The main purpose of this review, mainly based on preclinical studies, is to summarize the pharmacological and biochemical evidence regarding natural polyphenols against colorectal cancer and highlight areas that require future research.

RECENT FINDINGS

Typically, colorectal cancer is a potentially preventable and curable cancer arising from benign precancerous polyps found in the colon's inner lining. Colorectal cancer is the third most common cancer, with a lifetime risk of approximately 4 to 5%. Genetic background and environmental factors play major roles in the pathogenesis of colorectal cancer. Theoretically, a multistep process of colorectal carcinogenesis provides enough time for anti-tumor pharmacotherapy of colorectal cancer. Chronic colonic inflammation, oxidative stress, and gut microbiota imbalance have been found to increase the risk for colorectal cancer development by creating genotoxic stress within the intestinal environment to generate genetic mutations and epigenetic modifications. Currently, numerous natural polyphenols have shown anti-tumor properties against colorectal cancer in preclinical research, especially in colorectal cancer cell lines. In this review, the current literature regarding the etiology and epidemiology of colorectal cancer is briefly outlined. We highlight the findings of natural polyphenols in colorectal cancer from in vitro and in vivo studies. The scarcity of human trials data undermines the clinical use of natural polyphenols as anti-colorectal cancer agents, which should be undertaken in the future.

Development and evaluation of polyacrylamide microspheres loaded with phloretin and tantalum for transcatheter arterial embolization

Transcatheter arterial embolization is an effective treatment for liver cancer. However, the development of novel embolic agents remains a challenge. In this study, we evaluated polyacrylic acid microspheres loaded with phloretin and tantalum as potential embolic agents for liver cancer treatment. Microspheres were synthesised via emulsion polymerisation and characterised in terms of size, shape, and drug-loading efficiency. Nanosized tantalum powder (0 to 15%) was added to the microspheres as an X-ray blocking agent. The maximum drug-loading capacity of the microspheres was approximately 20 mg g-1. The phloretin-loaded microspheres showed a sustained drug release profile in vitro. The microspheres were also evaluated for their in vivo anticancer efficacy in a rabbit VX2 liver tumour model. In conclusion, polyacrylic acid microspheres loaded with phloretin and tantalum have great potential as novel embolic agents for transcatheter arterial embolization for liver cancer treatment.

Formulation, characterization, pharmacokinetics and antioxidant activity of phloretin oral granules

Phloretin (PHL), a flavonoid of the dihydrogen chalcone class, is reported to have low oral bioavailability due to its poor solubility and absorption. A common approach to enhance the solubility of such flavonoids is solubilization in a polymeric or lipidic matrix which would help in enhance dissolution rate and solubility. Accordingly, in the current study PHL was dissolved in Gelucire® 44/14 by melt-fusion technique and the viscous semisolid melt was adsorbed on a solid carrier to obtain free flowing granules. SeDeM-SLA (Solid-Liquid Adsorption) expert system was employed to select the most suitable carrier. This study achieved positive outcomes through the successful development of formulated oral PHL granules. The granules exhibited good stability, and favourable pharmacokinetic properties. In addition, the selected carrier effectively retained the antioxidant properties of PHL.

Chalcones and Gastrointestinal Cancers: Experimental Evidence

Colorectal (CRC) and gastric cancers (GC) are the most common digestive tract cancers with a high incidence rate worldwide. The current treatment including surgery, chemotherapy or radiotherapy has several limitations such as drug toxicity, cancer recurrence or drug resistance and thus it is a great challenge to discover an effective and safe therapy for CRC and GC. In the last decade, numerous phytochemicals and their synthetic analogs have attracted attention due to their anticancer effect and low organ toxicity. Chalcones, plant-derived polyphenols, received marked attention due to their biological activities as well as for relatively easy structural manipulation and synthesis of new chalcone derivatives. In this study, we discuss the mechanisms by which chalcones in both in vitro and in vivo conditions suppress cancer cell proliferation or cancer formation.

The Molecular Pharmacology of Phloretin: Anti-Inflammatory Mechanisms of Action

The isolation of phlorizin from the bark of an apple tree in 1835 led to a flurry of research on its inhibitory effect on glucose transporters in the intestine and kidney. Using phlorizin as a prototype drug, antidiabetic agents with more selective inhibitory activity towards glucose transport at the kidney have subsequently been developed. In contrast, its hydrolysis product in the body, phloretin, which is also found in the apple plant, has weak antidiabetic properties. Phloretin, however, displays a range of pharmacological effects including antibacterial, anticancer, and cellular and organ protective properties both in vitro and in vivo. In this communication, the molecular basis of its anti-inflammatory mechanisms that attribute to its pharmacological effects is scrutinised. These include inhibiting the signalling pathways of inflammatory mediators' expression that support its suppressive effect in immune cells overactivation, obesity-induced inflammation, arthritis, endothelial, myocardial, hepatic, renal and lung injury, and inflammation in the gut, skin, and nervous system, among others.

Phloretin, as a Potent Anticancer Compound: From Chemistry to Cellular Interactions

Phloretin is a natural dihydrochalcone found in many fruits and vegetables, especially in apple tree leaves and the Manchurian apricots, exhibiting several therapeutic properties, such as antioxidant, antidiabetic, anti-inflammatory, and antitumor activities. In this review article, the diverse aspects of the anticancer potential of phloretin are addressed, presenting its antiproliferative, proapoptotic, antimetastatic, and antiangiogenic activities in many different preclinical cancer models. The fact that phloretin is a planar lipophilic polyphenol and, thus, a membrane-disrupting Pan-Assay Interference compound (PAIN) compromises the validity of the cell-based anticancer activities. Phloretin significantly reduces membrane dipole potential and, therefore, is expected to be able to activate a number of cellular signaling pathways in a non-specific way. In this way, the effects of this minor flavonoid on Bax and Bcl-2 proteins, caspases and MMPs, cytokines, and inflammatory enzymes are all analyzed in the current review. Moreover, besides the anticancer activities exerted by phloretin alone, its co-effects with conventional anticancer drugs are also under discussion. Therefore, this review presents a thorough overview of the preclinical anticancer potential of phloretin, allowing one to take the next steps in the development of novel drug candidates and move on to clinical trials.

Therapeutic Potential and Pharmaceutical Development of a Multitargeted Flavonoid Phloretin

Phloretin is a flavonoid of the dihydrogen chalcone class, present abundantly in apples and strawberries. The beneficial effects of phloretin are mainly associated with its potent antioxidant properties. Phloretin modulates several signaling pathways and molecular mechanisms to exhibit therapeutic benefits against various diseases including cancers, diabetes, liver injury, kidney injury, encephalomyelitis, ulcerative colitis, asthma, arthritis, and cognitive impairment. It ameliorates the complications associated with diabetes such as cardiomyopathy, hypertension, depression, memory impairment, delayed wound healing, and peripheral neuropathy. It is effective against various microbial infections including Salmonella typhimurium, Listeria monocytogenes, Mycobacterium tuberculosis, Escherichia coli, Candida albicans and methicillin-resistant Staphylococcus aureus. Considering the therapeutic benefits, it generated interest for the pharmaceutical development. However, poor oral bioavailability is the major drawback. Therefore, efforts have been undertaken to enhance its bioavailability by modifying physicochemical properties and molecular structure, and developing nanoformulations. In the present review, we discussed the pharmacological actions, underlying mechanisms and molecular targets of phloretin. Moreover, the review provides insights into physicochemical and pharmacokinetic characteristics, and approaches to promote the pharmaceutical development of phloretin for its therapeutic applications in the future. Although convincing experimental data are reported, human studies are not available. In order to ascertain its safety, further preclinical studies are needed to encourage its pharmaceutical and clinical development.