Structural properties of polyphenols causing cell cycle arrest at G1 phase in HCT116 human colorectal cancer cell lines

The AsiDNA™ decoy mimicking DSBs protects the normal tissue from radiation toxicity through a DNA-PK/p53/p21-dependent G1/S arrest

AsiDNA™, a cholesterol-coupled oligonucleotide mimicking double-stranded DNA breaks, was developed to sensitize tumour cells to radio- and chemotherapy. This drug acts as a decoy hijacking the DNA damage response. Previous studies have demonstrated that standalone AsiDNA™ administration is well tolerated with no additional adverse effects when combined with chemo- and/or radiotherapy. The lack of normal tissue complication encouraged further examination into the role of AsiDNA™ in normal cells. This research demonstrates the radioprotective properties of AsiDNA™. In vitro, AsiDNA™ induces a DNA-PK/p53/p21-dependent G1/S arrest in normal epithelial cells and fibroblasts that is absent in p53 deficient and proficient tumour cells. This cell cycle arrest improved survival after irradiation only in p53 proficient normal cells. Combined administration of AsiDNA™ with conventional radiotherapy in mouse models of late and early radiation toxicity resulted in decreased onset of lung fibrosis and increased intestinal crypt survival. Similar results were observed following FLASH radiotherapy in standalone or combined with AsiDNA™. Mechanisms comparable to those identified in vitro were detected both in vivo, in the intestine and ex vivo, in precision cut lung slices. Collectively, the results suggest that AsiDNA™ can partially protect healthy tissues from radiation toxicity by triggering a G1/S arrest in normal cells.

Enhanced Expression of p53 and Suppression of PI3K/Akt/mTOR by Three Red Sea Algal Extracts: Insights on Their Composition by LC-MS-Based Metabolic Profiling and Molecular Networking

Brown algae comprise up to 2000 species with wide dissemination in temperate zones. A comprehensive untargeted metabolic profiling guided by molecular networking of three uninvestigated Red-Sea-derived brown algae, namely Sirophysalis trinodis, Polycladia myrica, and Turbinaria triquetra, led to the identification of over 115 metabolites categorized as glycerolipids, fatty acids, sterol lipids, sphingolipids, and phospholipids. The three algae exhibited low-to-moderate antioxidant capacity using DPPH and ABTS assays. Preliminary in vitro antiproliferative studies showed that the algal extracts displayed high cytotoxic activity against a panel of cancer cell lines. The most potent activity was recorded against MCF-7 with IC₅₀ values of 51.37 ± 1.19, 63.44 ± 1.13, and 59.70 ± 1.22 µg/mL for S. trinodis, P. myrica, and T. triquetra, respectively. The cytotoxicity of the algae was selective to MCF-7 without showing notable effects on the proliferation of normal human WISH cells. Morphological studies revealed that the algae caused cell shrinkage, increased cellular debris, triggered detachment, cell rounding, and cytoplasmic condensation in MCF-7 cancer cells. Mechanistic investigations using flow cytometry, qPCR, and Western blot showed that the algae induced apoptosis, initiated cell cycle arrest in the sub-G₀/G₁ phase, and inhibited the proliferation of cancer cells via increasing mRNA and protein expression of p53, while reducing the expression of PI3K, Akt, and mTOR.

Antioxidant and antiproliferative potentials of phenolic-rich extracts from biotransformed grape pomace in colorectal Cancer

BACKGROUND

Colorectal carcinoma is one of the most commonly diagnosed malignancies worldwide. Consumption of dietary supplements and nutraceuticals such as phenolic compounds may help combat colorectal carcinoma. The effect of two phenolic-rich extracts prepared from biotransformed grape pomace on the antioxidant properties and antiproliferative activity against two colorectal cancer cell lines (Caco-2 and SW620) were investigated.

METHODS

A 15-day solid-state fermentation with the white-rot fungi Phanerochaete chrysosporium and Trametes gibbosa was used to biotransform grape pomace. Solid-liquid extraction was then performed to extract bioactive compounds. The extract was analyzed for the determination of phenolic compounds by ultra-high performance liquid chromatography and in vitro assays of biological activities (antioxidant activity, antiproliferative activity, cell cycle analysis).

RESULTS

The 4 days of solid-state fermentation proved to be the optimal period to obtain the maximum yield of phenolic compounds. The tested extracts showed significant antioxidant and antiproliferative activities. Grape pomace treated with P. chrysosporium and T. gibbosa reduced cancer cell growth by more than 60% at concentrations (solid/liquid ratio) of 1.75 mg/mL and of 2.5 mg/mL, respectively. The cell cycle perturbations induced by the grape pomace extracts resulted in a significant increase in the number of cells in the S (9.8%) and G2/M (6.8%) phases of SW620 exposed to T. gibbosa after 48 hours, while P. chrysosporium increased the percentage of cells in the G1 phase by 7.7%. The effect of grape pomace extracts on Caco-2 was less pronounced.

CONCLUSIONS

The obtained results suggest the presence of bioactive compounds in biotransformed grape pomace as a residue from winemaking, which could be used to prevent colon cancer.

Unravelling Potential Health-Beneficial Properties of Corema album Phenolic Compounds: A Systematic Review

Corema (C.) album belongs to the family Ericaceae and can be found in the Iberian Peninsula, especially on the coastal areas facing the Atlantic coast. C. album berries have been used for centuries in traditional medicine. Recent studies have revealed that not only the berries but also the leaves have relevant antioxidant, antiproliferative, and anti-inflammatory properties, bringing this plant to the forefront of discussion. A systematic review of the literature was carried out to summarize the phenolic compounds and bioactive properties identified in C. album berries and leaves and to search for research gaps on this topic. The search was conducted in three electronic databases (PubMed, SCOPUS, and Web of Science) using PRISMA methodology. The inclusion criteria were the chemical compositions of the berries, leaves, or their extracts and their bioactive properties. The exclusion criteria were agronomic and archaeological research. The number of studies concerning phenolic compounds' composition and the bioactive properties of C. album berries and leaves is still limited (11 articles). However, the variety of polyphenolic compounds identified make it possible to infer new insights into their putative mechanism of action towards the suppression of NF-kB transcription factor activation, the modulation of inflammatory mediators/enzymes, the induction of apoptosis, the modulation of mitogen activated protein kinase, cell cycle arrest, and the reduction of oxidative stress. These factors can be of major relevance concerning the future use of C. album as nutraceuticals, food supplements, or medicines. Nevertheless, more scientific evidence concerning C. album's bioactivity is required.

Antiproliferative and Pro-Oxidant Effect of Polyphenols in Aqueous Leaf Extract of Passiflora alata Curtis on Activated T Lymphocytes from Non-Obese Diabetic (NOD SHILT/J) Mice

The antioxidant, anti-inflammatory and antiproliferative properties of Passiflora alata Curtis are due to the presence of polyphenols in its composition. Our previous work showed that non-obese diabetic (NOD) mice undergoing treatment with aqueous leaf extract of P. alata present reduced insulitis in the pancreas, possibly due to its anti-inflammatory properties. However, depending on the concentration and their ability to interact with other molecules, these phenolic compounds may promote oxidation reactions in some cellular components, such as proteins and lipids, thus presenting a pro-oxidant effect. The present work aimed to evaluate the in vitro effects of aqueous leaf extract of P. alata and its polyphenols (vitexin, isoorientin, rutin and catechin) on lymphocyte proliferation and viability, the cell cycle and oxidative stress. Our results showed that T lymphocytes stimulated with concanavalin A mitogen (ConA) and in the presence of IC50 concentrations of P. alata extract and polyphenols undergo cell injury via inhibition of proliferation, with these effects being more pronounced concerning CD4+ T cells (P. alata, 3.54 ± 0.34%; isoorientin, 57.07 ± 6.4%; vitexin, 16.95 ± 1.11%; catechin, 37.9 ± 4.2% and rutin, 40.14 ± 4.5%), compared to the non-treated group (77.17 ± 6.29) (p < 0.0001 for all comparisons). This process includes late apoptosis/necrosis induction (P. alata, 77.5 ± 0.7%; vitexin, 83 ± 3.3%; isoorientin, 83.8 ± 1.4%; catechin, 83 ± 1.9% and rutin, 74.9 ± 3.2, while the control presented 53.6% ± 3.1 (p < 0.0001 for all comparisons)) and mitochondrial depolarization leading to cell-death induction. Furthermore, an in vitro model of a mixed culture of NOD mice T cells with a mouse pancreatic beta-cell line (MIN6) showed increased intracellular nitric oxide and lipid peroxidation in NOD T cells submitted to P. alata extract (46.41 ± 3.08) compared to the untreated control group (33.57 ± 1.99, p = 0.01315). These results suggest that aqueous leaf extract of P. alata and the polyphenols in these leaves represent a target for translational research showing the plant’s benefits for developing new drugs with immunomodulatory properties against inflammatory diseases such as diabetes mellitus.

Polyphenols Extracts from Oil Production Waste Products (OPWPs) Reduce Cell Viability and Exert Anti-Inflammatory Activity via PPARγ Induction in Colorectal Cancer Cells

Olive oil production is associated with the generation of oil production waste products (OPWPs) rich in water-soluble polyphenols that represent serious environmental problems. Yet OPWPs can offer new opportunities by exploiting their bioactive properties. In this study, we chemically characterized OPWPs polyphenolic extracts and investigated their biological activities in normal and colorectal cancer cells. Hydroxytyrosol (HTyr), the major constituent of these extracts, was used as the control. We show that both HTyr and the extracts affect cell viability by inducing apoptosis and cell cycle arrest. They downregulate inflammation by impairing NF-κB phosphorylation and expression of responsive cytokine genes, as TNF-α and IL-8, at both mRNA and protein levels, and prevent any further increase elicited by external challenges. Mechanistically, HTyr and the extracts activate PPARγ while hampering pro-inflammatory genes expression, acting as a specific agonist, likely through a trans-repression process. Altogether, OPWPs polyphenolic extracts show stronger effects than HTyr, conceivably due to additive or synergistic effects of all polyphenols contained. They display anti-inflammatory properties and these results may pave the way for improving OPWPs extraction and enrichment methods to reduce the environmental impact and support their use to ameliorate the inflammation associated with diseases and tumors.

Anti-Cancer Properties of Stevia rebaudiana; More than a Sweetener

Stevia rebaudiana Bertoni is a perennial shrub from Paraguay that is nowadays widely cultivated, since it is increasingly being utilized as a sugar substitute in various foodstuffs due to its sweetness and minimal caloric content. These properties of the plant’s derivatives have spurred research on their biological activities revealing a multitude of benefits to human health, including antidiabetic, anticariogenic, antioxidant, hypotensive, antihypertensive, antimicrobial, anti-inflammatory and antitumor actions. To our knowledge, no recent reviews have surveyed and reported published work solely on the latter. Consequently, our main objective was to present a concise, literature-based review of the biological actions of stevia derivatives in various tumor types, as studied in in vitro and in vivo models of the disease. With global cancer estimates suggesting a 47% increase in cancer cases by 2040 compared to 2020, the data reviewed in this article should provide a better insight into Stevia rebaudiana and its products as a means of cancer prevention and therapy within the context of a healthy diet.

Complementary effects of Orthosiphon stamineus standardized ethanolic extract and rosmarinic acid in combination with gemcitabine on pancreatic cancer

BACKGROUND

Pancreatic cancer is one of the most notorious cancers and is known for its highly invasive characteristics, drug resistance, and metastatic progression. Unfortunately, many patients with advanced pancreatic cancer become insensitive towards gemcitabine treatment. Orthosiphon stamineus (O.s) is used widely as a traditional medicine for the treatment of multiple ailments, including cancer in South East Asia. The present in vitro study was designed to investigate the complementary effects of an ethanolic extract of O.s (Et. O.s) or rosmarinic acid in combination with gemcitabine on Panc-1 pancreatic cancer cells.

METHOD

Cell viability and colony formation assays were used to determine the 50% inhibitory concentration (IC50) of Et. O.s, rosmarinic acid, and gemcitabine. Different doses of gemcitabine in combination with Et. O.s or rosmarinic acid were tested against Panc-1 to select the best concentrations which possessed synergistic effects. Elucidation of molecular mechanisms responsible for mediating chemo-sensitivity in Panc-1 was performed using Quantitative Real-time PCR (QPCR), flow cytometry and immunohistochemistry.

RESULTS

Et. O.s was found to significantly sensitise Panc-1 towards gemcitabine by reducing the gene expression of multidrug-resistant protein family (MDR) (MDR-1, MRP-4, and MRP-5) and molecules related to epithelial-mesenchymal transition (ZEB-1 and Snail-1). An induction of the human equilibrate nucleoside transporter-1 (hENT-1) gene was also found in cells treated with Et. O.s-gemcitabine. The Et. O.s-gemcitabine combination induced cellular senescence, cell death and cell cycle arrest in Panc-1. In addition, the inhibition of Notch signalling was demonstrated through the downregulation of Notch 1 intracellular domain in this treatment group. In contrast, rosmarinic acid-gemcitabine combination showed no additional effects on cellular senescence, apoptosis, epithelial mesenchymal transition (EMT) markers, the MRP-4 and MRP-5 multi-drug resistance protein family, hENT-1, and the Notch pathway through Notch 1 intracellular domain.

CONCLUSION

This study provides valuable insights on the use of Et. O.s to complement gemcitabine in targeting pancreatic cancer in vitro, suggesting its potential use as a novel complementary treatment in pancreatic cancer patients.

Single Crystal X-Ray Structure for the Disordered Two Independent Molecules of Novel Isoflavone: Synthesis, Hirshfeld Surface Analysis, Inhibition and Docking Studies on IKKβ of 3-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6,7-dimethoxy-4H-chromen-4-one

The structure of the isoflavone compound, 3-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-6,7-dimethoxy-4H-chromen-4-one (5), was elucidated by 2D-NMR spectra, mass spectrum and single crystal X-ray crystallography. Compound 5, C19H16O6, was crystallized in the monoclinic space group P21/c with the cell parameters; a = 12.0654(5) Å, b =11.0666(5) Å, c = 23.9550(11) Å, β = 101.3757(16)°, V = 3135.7(2) Å3, and Z = 8. The asymmetric unit of compound 5 consists of two independent molecules 5I and 5II. Both molecules exhibit the disorder of each methylene group present in their 1,4-dioxane rings with relative occupancies of 0.599(10) (5I) and 0.812(9) (5II) for the major component A, and 0.401(10) (5I) and 0.188(9) (5II) for the minor component B, respectively. Each independent molecule revealed remarkable discrepancies in bond lengths, bond angles and dihedral angles in the disordered regions of 1,4-dioxane rings. The common feature of the molecules 5I and 5II are a chromone ring and a benzodioxin ring, which are more tilted towards each other in 5I than in 5II. An additional difference between the molecules is seen in the relative disposition of two methoxy substituents. In the crystal, the molecule 5II forms inversion dimers which are linked into chains along an a-axis direction by intermolecular C–H⋯O interactions. Additional C–H⋯O hydrogen bonds connected the molecules 5I and 5II each other to form a three-dimensional network. Hirshfeld surface analysis evaluated the relative intermolecular interactions which contribute to each crystal structure 5I and 5II. Western blot analysis demonstrated that compound 5 inhibited the TNFα-induced phosphorylation of IKKα/β, resulting in attenuating further downstream NF-κB signaling. A molecular docking study predicted the possible binding of compound 5 to the active site of IKKβ. Compound 5 showed an inhibitory effect on the clonogenicity of HCT116 human colon cancer cells. These results suggest that compound 5 can be used as a platform for the development of an anti-cancer agent targeting IKKα/β.

3-(2-Methoxyphenyl)-2,3-dihydro-1H-benzo[f]chromen-1-one

In the title flavanone, the mol­ecules are linked by weak C—H⋯O inter­actions into [101] chains.

In the title compound, C₂₀H₁₆O₃, the 2-meth­oxy­phenyl ring is tilted by 50.67 (3)° with respect to the naphthyl ring system. The central pyran ring has an envelope conformation with the C atom bearing the pendant ring system as the flap. The meth­oxy group attached to the benzene ring is slightly twisted [C—C—O—C = −15.2 (1)°] from the ring. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into C(7) chains propagating along [101].

Targeting PI3K/Akt/mTOR signaling pathway by polyphenols: Implication for cancer therapy

Cancer is one of the biggest challenges facing medicine and its cure is regarded to be the Holy Grail of medicine. Therapy in cancer is consisted as various artificial cytotoxic agents and radiotherapy, and recently immunotherapy. Recently much attention has been directed to the use of natural occurring agents in cancer therapy. One of the main group of agents utilized in this regard is polyphenols which are found abundantly in berries, fruits and vegetables. Polyphenols show to exert direct and indirect effects in progression of cancer, angiogenesis, proliferation and enhancing resistance to treatment. One of the cellular pathways commonly affected by polyphenols is PI3K/Akt/mTOR pathway, which has far ranging effects on multiple key aspects of cellular growth, metabolism and death. In this review article, evidence regarding the biology of polyphenols in cancer via PI3K/Akt/mTOR pathway is discussed and their application on cancer pathophysiology in various types of human malignancies is shown.

Overcoming Multidrug Resistance by Activating Unfolded Protein Response of the Endoplasmic Reticulum in Cisplatin-Resistant A2780/CisR Ovarian Cancer Cells

Cisplatin is a widely used anti-cancer agent. However, the effectiveness of cisplatin has been limited by the commonly developed drug resistance. This study aimed to investigate the potential effects of endoplasmic reticulum (ER) stress to overcome drug resistance using the cisplatin-resistant A2780/CisR ovarian cancer cell model. The synthetic chalcone derivative (E)-3-(3,5-dimethoxyphenyl)-1-(2-methoxyphenyl)prop-2-en-1-one (named DPP23) is an ER stress inducer. We found that DPP23 triggered apoptosis in both parental cisplatin-sensitive A2780 and cisplatin-resistant A2780/CisR ovarian cancer cells due to activation of reactive oxygen species (ROS)-mediated unfolded protein response (UPR) pathway in the endoplasmic reticulum. This result suggests that ROS-mediated UPR activation is potential in overcoming drug resistance. DPP23 can be used as a target pharmacophore for the development of novel chemotherapeutic agents capable of overcoming drug resistance in cancer cells, particularly ovarian cancer cells.

Modulation of Nerve Cell Differentiation: Role of Polyphenols and of Contactin Family Components

In this study the mechanisms are explored, which modulate expression and function of cell surface adhesive glycoproteins of the Immunoglobulin Supergene Family (IgSF), and in particular of its Contactin subset, during neuronal precursor developmental events. In this context, a specific topic concerns the significance of the expression profile of such molecules and their ability to modulate signaling pathways activated through nutraceuticals, in particular polyphenols, administration. Both in vitro and in vivo approaches are chosen. As for the former, by using as a model the human SH-SY5Y neuroblastoma line, the effects of grape seed polyphenols are evaluated on proliferation and commitment/differentiation events along the neuronal lineage. In SH-SY5Y cell cultures, polyphenols were found to counteract precursor proliferation while promoting their differentiation, as deduced by studying their developmental parameters through the expression of cell cycle and neuronal commitment/differentiation markers as well as by measuring neurite growth. In such cultures, Cyclin E expression and BrdU incorporation were downregulated, indicating reduced precursor proliferation while increased neuronal differentiation was inferred from upregulation of cell cycle exit (p27^–Kip) and neuronal commitment (NeuN) markers as well as by measuring neurite length through morphometric analysis. The polyphenol effects on developmental parameters were also explored in vivo, in cerebellar cortex, by using as a model the TAG/F3 transgenic line, which undergoes delayed neural development as a consequence of Contactin1 adhesive glycoprotein upregulation and premature expression under control of the Contactin2 gene (Cntn-2) promoter. In this transgenic line, a Notch pathway activation is known to occur and polyphenol treatment was found to counteract such an effect, demonstrated through downregulation of the Hes-1 transcription factor. Polyphenols also downregulated the expression of adhesive glycoproteins of the Contactin family themselves, demonstrated for both Contactin1 and Contactin2, indicating the involvement of changes in the expression of the underlying genes in the observed phenotype. These data support the hypothesis that the complex control exerted by polyphenols on neural development involves modulation of expression and function of the genes encoding cell adhesion molecules of the Contactin family and of the associated signaling pathways, indicating potential mechanisms whereby such compounds may control neurogenesis.

Anti-cancer effects of polyphenols via targeting p53 signaling pathway: updates and future directions

The anticancer effects of polyphenols are ascribed to several signaling pathways including the tumor suppressor gene tumor protein 53 (p53). Expression of endogenous p53 is silent in various types of cancers. A number of polyphenols from a wide variety of dietary sources could upregulate p53 expression in several cancer cell lines through distinct mechanisms of action. The aim of this review is to focus the significance of p53 signaling pathways and to provide molecular intuitions of dietary polyphenols in chemoprevention by monitoring p53 expression that have a prominent role in tumor suppression.

The synthetic chalcone derivative 2-hydroxy-3',5,5'-trimethoxychalcone induces unfolded protein response-mediated apoptosis in A549 lung cancer cells

The synthetic chalcone derivative 2-hydroxy-3',5,5'-trimenthoxyochalcone (named DK-139) exhibits anti-inflammatory and anti-tumor invasion properties. However, effects of DK-139 on tumor cell growth remain unknown. In the present study, we evaluated the inhibitory activity of DK-139 against human lung cancer cells. Treatment with DK-139 inhibited clonogenicity in various lung cancers and stimulated the caspase cascade, leading to the apoptosis of A549 lung cancer cells. To investigate the mode of action of DK-139-induced apoptosis, we analyzed the effect of DK-139 on the endoplasmic reticulum (ER) stress response. DK-139 increased expression of ER stress sensors, including p-PERK, GRP78/BiP, and IRE1α. IRE1α-regulated XBP-1 mRNA splicing and PERK-induced ATF4 expression was also upregulated following DK-139 treatment. In addition, expression levels of the pro-apoptotic transcription factor CHOP and its downstream target Bim, which is involved in mitochondria-mediated apoptosis, were increased by DK-139 treatment. These results suggest that DK-139 triggers caspase-mediated apoptosis via the ER stress-activated unfolded protein response (UPR) pathway. We propose that the synthetic chalcone derivative DK-139 may be used as a potential agent for the prevention and/or treatment of human lung cancer.

Polyphenols as Promising Drugs against Main Breast Cancer Signatures

Breast cancer is one of the most common neoplasms worldwide, and in spite of clinical and pharmacological advances, it is still a clinical problem, causing morbidity and mortality. On the one hand, breast cancer shares with other neoplasms some molecular signatures such as an imbalanced redox state, cell cycle alterations, increased proliferation and an inflammatory status. On the other hand, breast cancer shows differential molecular subtypes that determine its prognosis and treatment. These are characterized mainly by hormone receptors especially estrogen receptors (ERs) and epidermal growth factor receptor 2 (HER2). Tumors with none of these receptors are classified as triple negative breast cancer (TNBC) and are associated with a worse prognosis. The success of treatments partially depends on their specificity and the adequate molecular classification of tumors. New advances in anticancer drug discovery using natural compounds have been made in the last few decades, and polyphenols have emerged as promising molecules. They may act on various molecular targets because of their promiscuous behavior, presenting several physiological effects, some of which confer antitumor activity. This review analyzes the accumulated evidence of the antitumor effects of plant polyphenols on breast cancer, with special attention to their activity on ERs and HER2 targets and also covering different aspects such as redox balance, uncontrolled proliferation and chronic inflammation.

CDK4/6 inhibitor-SHR6390 exerts potent antitumor activity in esophageal squamous cell carcinoma by inhibiting phosphorylated Rb and inducing G1 cell cycle arrest

Background

Cell cycle dysregulation is common in human malignancies, and CDK4/6 inhibitors targeting cell cycle have potential antitumor activity. SHR6390 is a novel small molecule inhibitor specifically targeting the CDK4/6 pathway. However, the role of SHR6390 in esophageal squamous cell carcinoma (ESCC) remains unknown, which will be investigated in our study.

Methods

Eca 109, Eca 9706, and KYSE-510 ESCC cell lines were chosen for further analysis. The effect of SHR6390 on cell viability, cell cycle and cell apoptosis, the status of kinases in Cyclin D1-CDK4/6-Rb pathway were determined by MTS assay, flow cytometry, and western blotting, respectively. Cell-derived and patient-derived xenografts were established to investigate the effects of drugs in vivo.

Results

SHR6390 could suppress cell proliferation in vitro cell lines and inhibit tumor growth in vivo PDX models with different drug susceptibility. The effective treatment of SHR6390 induced the inhibition of phosphorylated Rb and cell cycle arrest at G1 phase both in cell lines and in xenografts. SHR6390 combined with paclitaxel or cisplatin offered synergistic inhibitory effects in cell-derived xenografts especially in Eca 9706 xenografts which showed relative lower sensitivity of SHR6390 single. Moreover, low expression of CDK6 and/or high expression of Cyclin D1 might be associated with high sensitivity of SHR6390, which would be validated in the future.

Conclusions

CDK4/6 inhibitor-SHR6390 exerted potential antitumor activity against ESCC cell lines and xenografts, and evaluation of CDK6 and Cyclin D1 expressions might be helpful to select patients beneficial from SHR6390, which provided evidences for future clinical trials.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-017-1231-7) contains supplementary material, which is available to authorized users.

Quantitative Relationships Between the Cytotoxicity of Flavonoids on the Human Breast Cancer Stem-Like Cells MCF7-SC and Their Structural Properties

As some breast cancer-related deaths can be attributed to the metastasis of cancer stem cells, chemotherapeutic agents targeting breast cancer stem cells are of interest as a potential treatment. Flavonoids that exhibit cytotoxicity on breast cancer stem cells have rarely been observed. Thus, the objective of this study was to measure potential cytotoxic effects of 42 different flavonoids on the human breast cancer stem-like cell line, MCF7-SC. The relationship between flavonoid structural properties and cytotoxicity has not been reported previously; therefore, we determined quantitative structure-activity relationships using both comparative molecular field analysis and comparative molecular similarity analysis. Further biological experiments including Western blot analysis, flow cytometry, and immunofluorescence microscopy were also conducted on the most cytotoxic 8-chloroflavanone.