SU5416 and EGCG work synergistically and inhibit angiogenic and survival factors and induce cell cycle arrest to promote apoptosis in human malignant neuroblastoma SH-SY5Y and SK-N-BE2 cells

Development of red blood cell-derived extracellular particles as a biocompatible nanocarrier of microRNA-204 (REP-204) to harness anti-neuroblastoma effect

Neuroblastoma (NB) is the most common extracranial solid tumor in the pediatric population with a high degree of heterogeneity in clinical outcomes. Upregulation of the tumor suppressor miR-204 in neuroblastoma is associated with good prognosis. Although miR-204 has been recognized as a potential therapeutic candidate, its delivery is unavailable. We hypothesized that REP-204, the red blood cell-derived extracellular particles (REP) with miR-204 loading, can suppress neuroblastoma cells in vitro. After miR-204 loading by electroporation, REP-204, but not REP carriers, inhibited the viability, migration, and 3D spheroid growth of neuroblastoma cells regardless of MYCN amplification status. SWATH-proteomics revealed that REP-204 treatment may trigger a negative regulation of mRNA splicing by the spliceosome, suppression of amino acid metabolism and protein production, and prevent SLIT/ROBO signaling-mediated cell migration, to halt neuroblastoma tumor growth and metastasis. The therapeutic efficacy of REP-204 should be further investigated in preclinical models and clinical studies.

The medicinal value of tea drinking in the management of COVID-19

Corona Virus Disease 2019 (COVID-19) is presently the largest international public health event, individuals infected by the virus not only have symptoms such as fever, dry cough, and lung infection at the time of onset, but also possibly have sequelae in the cardiovascular system, respiratory system, nervous system, mental health and other aspects. However, numerous studies have depicted that the active ingredients in tea show good antiviral effects and can treat various diseases by regulating multiple pathways, and the therapeutic effects are associated with the categories of chemical components in tea. In this review, the differences in the content of key active ingredients in different types of tea are summarized. In addition, we also highlighted their effects on COVID-19 and connected sequelae, further demonstrating the possibility of developing a formulation for the prevention and treatment of COVID-19 and its sequelae through tea extracts. We have a tendency to suggest forestalling and treating COVID-19 and its sequelae through scientific tea drinking.

Aptamer Functionalized Upconversion Nanotheranostic Agent With Nuclear Targeting as the Highly Localized Drug-Delivery System of Doxorubicin

As a widely used anticancer drug, doxorubicin (DOX) could induce cell death mainly via interfering with DNA activity; thus, DOX could perform therapeutic effects mainly in the cell nucleus. However, most of the reported drug delivery systems lacked the well localization in the nucleus and released DOX molecules into the cytoplasm. Due to formidable barriers formed in the nuclear envelope, only around 1% of DOX could reach the nucleus and keep active. Therefore, DOX molecules were inevitably overloaded to achieve the desired therapeutic efficacy, which would induce serious side effects. Herein, we developed a highly localized drug nanocarrier for in situ release of DOX molecules to their action site where they could directly interfere with the DNA activity. In this work, we used cationic polymer-modified upconversion nanoparticles (UCNPs) as the luminescence core and gene carrier, while aptamers served as the DNA nanotrain to load DOX. Finally, the prepared nanotheranostic agent displayed good targetability, high cell apoptosis ratio (93.04%) with quite lower concentration than the LC50 of DOX, and obvious inhibition on tumor growth.

Molecular mechanisms of action of epigallocatechin gallate in cancer: Recent trends and advancement

Epigallocatechin gallate (EGCG), also known as epigallocatechin-3-gallate, is an ester of epigallocatechin and gallic acid. EGCG, abundantly found in tea, is a polyphenolic flavonoid that has the potential to affect human health and disease. EGCG interacts with various recognized cellular targets and inhibits cancer cell proliferation by inducing apoptosis and cell cycle arrest. In addition, scientific evidence has illustrated the promising role of EGCG in inhibiting tumor cell metastasis and angiogenesis. It has also been found that EGCG may reverse drug resistance of cancer cells and could be a promising candidate for synergism studies. The prospective importance of EGCG in cancer treatment is owed to its natural origin, safety, and low cost which presents it as an attractive target for further development of novel cancer therapeutics. A major challenge with EGCG is its low bioavailability which is being targeted for improvement by encapsulating EGCG in nano-sized vehicles for further delivery. However, there are major limitations of the studies on EGCG, including study design, experimental bias, and inconsistent results and reproducibility among different study cohorts. Additionally, it is important to identify specific EGCG pharmacological targets in the tumor-specific signaling pathways for development of novel combined therapeutic treatments with EGCG. The present review highlights the ongoing development to identify cellular and molecular targets of EGCG in cancer. Furthermore, the role of nanotechnology-mediated EGCG combinations and delivery systems will also be discussed.

EGCG Mediated Targeting of Deregulated Signaling Pathways and Non-Coding RNAs in Different Cancers: Focus on JAK/STAT, Wnt/β-Catenin, TGF/SMAD, NOTCH, SHH/GLI, and TRAIL Mediated Signaling Pathways

Decades of research have enabled us to develop a better and sharper understanding of multifaceted nature of cancer. Next-generation sequencing technologies have leveraged our existing knowledge related to intra- and inter-tumor heterogeneity to the next level. Functional genomics have opened new horizons to explore deregulated signaling pathways in different cancers. Therapeutic targeting of deregulated oncogenic signaling cascades by products obtained from natural sources has shown promising results. Epigallocatechin-3-gallate (EGCG) has emerged as a distinguished chemopreventive product because of its ability to regulate a myriad of oncogenic signaling pathways. Based on its scientifically approved anticancer activity and encouraging results obtained from preclinical trials, it is also being tested in various phases of clinical trials. A series of clinical trials associated with green tea extracts and EGCG are providing clues about significant potential of EGCG to mechanistically modulate wide ranging signal transduction cascades. In this review, we comprehensively analyzed regulation of JAK/STAT, Wnt/β-catenin, TGF/SMAD, SHH/GLI, NOTCH pathways by EGCG. We also discussed most recent evidence related to the ability of EGCG to modulate non-coding RNAs in different cancers. Methylation of the genome is also a widely studied mechanism and EGCG has been shown to modulate DNA methyltransferases (DNMTs) and protein enhancer of zeste-2 (EZH2) in multiple cancers. Moreover, the use of nanoformulations to increase the bioavailability and thus efficacy of EGCG will be also addressed. Better understanding of the pleiotropic abilities of EGCG to modulate intracellular pathways along with the development of effective EGCG delivery vehicles will be helpful in getting a step closer to individualized medicines.

The aryl hydrocarbon receptor is required for induction of p21cip1/waf1 expression and growth inhibition by SU5416 in hepatoma cells

The aryl hydrocarbon receptor (AhR) is a potential clinical target for cancer and autoimmune dysfunction. Identifying selective AhR modulators that produce desirable clinical outcomes represents an opportunity for developing new anti-cancer agents. Repurposing clinically-used drugs with established safety profiles that activate the AhR represents a good starting place to pursue this goal. In this study, we characterized the AhR-dependent effects of SU5416 (Semaxanib) following its identification in a small-molecule library screen. SU5416 potently activated AhR-dependent reporter genes, induced AhR nuclear localization, facilitated AhR-DNA binding, and increased, expression of its endogenous target genes. SU5416 significantly inhibited proliferation of Hepa1 hepatoma cells in an AhR-dependent manner, but did not induce apoptosis. SU5416 also inhibited the growth of human HepG2 liver cancer cells. The effects of SU5416 correlated with an increased G1 population and increased expression of cell cycle inhibitor p21^cip1/waf1 at both the mRNA and protein level. Increased expression of p21^cip1/waf1 by SU5416 required expression of both AhR and Arnt. In addition, evidence for long-term activation of the AhR in vivo by a single dose of SU5416 was identified by analyzing published microarray data. Our results provide support for continued investigation of the AhR as therapeutic for cancers such as hepatocellular carcinoma. In addition, our findings raise the possibility that some of the previously observed anti-proliferative effects of SU5416 may be due to activation of the AhR.

Synergistic enhancement of anticancer effects on numerous human cancer cell lines treated with the combination of EGCG, other green tea catechins, and anticancer compounds

PURPOSE

In 2008, we reported that 10 Japanese-size cups of green tea daily, supplemented with tablets of green tea extract (GTE), reduced the recurrence of colorectal adenoma by 51.6% in patients after polypectomy. Based on these results, we paid special attention to Japanese cancer patients, who consume green tea every day and are administered anticancer drugs. This encouraged us to study whether the combination of green tea catechins and anticancer drugs has the potential to enhance the efficacy of the drugs.

RESULTS AND DISCUSSION

The combination of GTE and NSAIDs synergistically inhibited tumor development in rodents through the activation of the GADD153-DR5-TRAIL apoptotic pathway. Since then, this study was further extended by various investigators to the combinations of EGCG and other green tea catechins with anticancer compounds, the latter of which include NSAIDs, phytochemicals, and anticancer drugs. In order to demonstrate whether diversity of the combinations would generally induce synergistic anticancer effects on numerous human cancer cell lines, we studied the results of 42 in vitro combination experiments and the synergistic inhibition of tumor volume of 13 combination experiments using xenograft mouse models, which were previously reported by other investigators. The various combinations of EGCG and anticancer compounds induced similar synergistic anticancer effects for both in vitro and in vivo experiments, and showed an average reduction in tumor volume by 70.3%. Considering the evidence showing that treatment with EGCG inhibited self-renewal of cancer stem cells, the combination shows a great advantage.

CONCLUSION

Green tea is a cancer preventive for humans, showing a new trend of green tea catechins as synergists with anticancer compounds.

Sunitinib produces neuroprotective effect via inhibiting nitric oxide overproduction

BACKGROUND

Sunitinib is an inhibitor of the multiple receptor tyrosine kinases (RTKs) for cancer therapy. Some sunitinib analogues could prevent neuronal death induced by various neurotoxins. However, the neuroprotective effects of sunitinib have not been reported.

METHODS

Cerebellar granule neurons (CGNs) and SH-SY5Y cells were exposed to low-potassium and MPP(+) challenges, respectively. MTT assay, FDA/PI staining, Hoechst staining, DAF-FM, colorimetric nitric oxide synthase (NOS) activity assay, and Western blotting were applied to detect cell viability, NO production, NOS activity, and neuronal NOS (nNOS) expression. Short hairpin RNA was used to decrease nNOS expression. In vitro NOS enzyme activity assay was used to determine the direct inhibition of nNOS by sunitinib.

RESULTS

Sunitinib prevented low-potassium-induced neuronal apoptosis in CGNs and MPP(+) -induced neuronal death in SH-SY5Y cells. However, PTK787, another RTK inhibitor, failed to decrease neurotoxicity in the same models. Sunitinib reversed the increase in NO levels, NOS activity, and nNOS expression induced by low potassium or MPP(+) . Knockdown of nNOS expression partially abolished the neuroprotective effects of sunitinib. Moreover, sunitinib directly inhibited nNOS enzyme activity.

CONCLUSIONS

Sunitinib exerts its neuroprotective effects by inhibiting NO overproduction, possibly via the inhibition of nNOS activity and the decrease in nNOS expression.

Combination of LC3 shRNA plasmid transfection and genistein treatment inhibited autophagy and increased apoptosis in malignant neuroblastoma in cell culture and animal models

Malignant neuroblastoma is an extracranial solid tumor that usually occurs in children. Autophagy, which is a survival mechanism in many solid tumors including malignant neuroblastoma, deters the efficacy of conventional chemotherapeutic agents. To mimic starvation, we used 200 nM rapamycin that induced autophagy in human malignant neuroblastoma SK-N-BE2 and IMR-32 cells in cell culture and animal models. Combination of microtubule associated protein light chain 3 short hairpin RNA (LC3 shRNA) plasmid transfection and genistein (GST) treatment was tested for inhibiting rapamycin-induced autophagy and promoting apoptosis. The best synergistic efficacy caused the highest decrease in cell viability due to combination of 50 nM LC3 shRNA plasmid transfection and 25 µM GST treatment in rapamycin-treated SK-N-BE2 cells while combination of 100 nM LC3 shRNA plasmid transfection and 25 µM GST treatment in rapamycin-treated IMR-32 cells. Quantitation of acidic vesicular organelles confirmed that combination of LC3 shRNA plasmid transfection and GST treatment prevented rapamycin-induced autophagy due to down regulation of autophagy promoting marker molecules (LC3 II, Beclin 1, TLR-4, and Myd88) and upregulation of autophagy inhibiting marker molecules (p62 and mTOR) in both cell lines. Apoptosis assays showed that combination therapy most effectively activated mitochondrial pathway of apoptosis in human malignant neuroblastoma in cell culture and animal models. Collectively, our current combination of LC3 shRNA plasmid transfection and GST treatment could serve as a promising therapeutic strategy for inhibiting autophagy and increasing apoptosis in human malignant neuroblastoma in cell culture and animal models.

Green tea polyphenol epigallocatechin-3-gallate (EGCG) as adjuvant in cancer therapy

BACKGROUND & AIMS

Green tea catechins, especially epigallocatechin-3-gallate (EGCG), have been associated with cancer prevention and treatment. This has resulted in an increased number of studies evaluating the effects derived from the use of this compound in combination with chemo/radiotherapy. This review aims at compiling latest literature on this subject.

METHODS

Keywords including EGCG, cancer, chemotherapy, radiotherapy and side effects, were searched using PubMed and ScienceDirect databases to identify, analyze, and summarize the research literature on this topic. Most of the studies on this subject up to date are preclinical. Relevance of the findings, impact factor, and date of publication were critical parameters for the studies to be included in the review.

RESULTS

Additive and synergistic effects of EGCG when combined with conventional cancer therapies have been proposed, and its anti-inflammatory and antioxidant activities have been related to amelioration of cancer therapy side effects. However, antagonistic interactions with certain anticancer drugs might limit its clinical use.

CONCLUSIONS

The use of EGCG could enhance the effect of conventional cancer therapies through additive or synergistic effects as well as through amelioration of deleterious side effects. Further research, especially at the clinical level, is needed to ascertain the potential role of EGCG as adjuvant in cancer therapy.

KLF4 overexpression and apigenin treatment down regulated anti-apoptotic Bcl-2 proteins and matrix metalloproteinases to control growth of human malignant neuroblastoma SK-N-DZ and IMR-32 cells

Neuroblastoma is a childhood tumor that arises from immature neuroblasts of the sympathetic nervous system. Krüpple-like factor 4 (KLF4) is a transcription factor, the precise function of which in neuroblastoma is unclear. We examined the effects of KLF4 overexpression and apigenin (APG) treatment in human malignant neuroblastoma SK-N-DZ and IMR-32 cell lines. KLF4 overexpression in both SK-N-DZ and IMR-32 cell lines was confirmed by laser scanning immunofluorescent confocal microscopy and Western blotting. We found that 100 nM KLF4 plasmid and 25 μM APG synergistically inhibited the growth of SK-N-DZ and IMR-32 cells. We also found increase in KLF4 expression in response to treatment with various concentrations of APG. Combination of KLF4 plasmid and APG treatment significantly increased the amounts of apoptosis in both cell lines when compared with control vector or single treatment. We also noticed that the combination therapy decreased expression of the anti-apoptotic proteins Bcl-2 and Mcl-1, increased expression of the pro-apoptotic proteins Bax, Noxa, and Puma, upregulated p53, and caused activation of caspase-3 for cleavage of the inhibitor of caspase-activated DNase (ICAD) leading to completion of apoptosis machinery. Further, combination of KLF4 overexpression and APG treatment was highly effective in inhibiting migration of both neuroblastoma cell lines and was associated with down regulation of matrix metalloproteinases (MMPs) such as MMP-2 and MMP-9. Collectively, our results from this investigation strongly suggest that KLF4 functions as a tumor suppressor and potentiates the anti-cancer activities of APG in two different human malignant neuroblastoma cell lines.

Survivin knockdown increased anti-cancer effects of (-)-epigallocatechin-3-gallate in human malignant neuroblastoma SK-N-BE2 and SH-SY5Y cells

Neuroblastoma is a solid tumor that mostly occurs in children. Malignant neuroblastomas have poor prognosis because conventional chemotherapeutic agents are hardly effective. Survivin, which is highly expressed in some malignant neuroblastomas, plays a significant role in inhibiting differentiation and apoptosis and promoting cell proliferation, invasion, and angiogenesis. We examined consequences of survivin knockdown by survivin short hairpin RNA (shRNA) plasmid and then treatment with (-)-epigallocatechin-3-gallate (EGCG), a green tea flavonoid, in malignant neuroblastoma cells. Our Western blotting and laser scanning confocal immunofluorescence microscopy showed that survivin was highly expressed in malignant neuroblastoma SK-N-BE2 and SH-SY5Y cell lines and slightly in SK-N-DZ cell line. Expression of survivin was very faint in malignant neuroblastoma IMR32 cell line. We transfected SK-N-BE2 and SH-SY-5Y cells with survivin shRNA, treated with EGCG, and confirmed knockdown of survivin at mRNA and protein levels. Survivin knockdown induced morphological features of neuronal differentiation, as we observed following in situ methylene blue staining. Combination of survivin shRNA and EGCG promoted neuronal differentiation biochemically by increases in the expression of NFP, NSE, and e-cadherin and also decreases in the expression of Notch-1, ID2, hTERT, and PCNA. Our in situ Wright staining and Annexin V-FITC/PI staining showed that combination therapy was highly effective in inducing, respectively, morphological and biochemical features of apoptosis. Apoptosis occurred with activation of caspase-8 and cleavage of Bid to tBid, increase in Bax:Bcl-2 ratio, mitochondrial release of cytochrome c, and increases in the expression and activity of calpain and caspase-3. Combination therapy decreased migration of cells through matrigel and inhibited proliferative (p-Akt and NF-κB), invasive (MMP-2 and MMP-9), and angiogenic (VEGF and b-FGF) factors. Also, in vitro network formation ability of cells was significantly inhibited by survivin silencing and completely by combination of survivin silencing and EGCG treatment. Collectively, survivin silencing potentiated anti-cancer effects of EGCG in human malignant neuroblastoma cells having survivin overexpression.