Curcumin induces apoptosis in human leukemic cell lines through an IFIT2-dependent pathway

Sequence Diversity in the 3' Untranslated Region of Alphavirus Modulates IFIT2-Dependent Restriction in a Cell Type-Dependent Manner

Alphaviruses (family Togaviridae) are a diverse group of positive-sense RNA (+ssRNA) viruses that are transmitted by arthropods and are the causative agent of several significant human and veterinary diseases. Interferon (IFN)-induced proteins with tetratricopeptide repeats (IFITs) are a family of RNA-binding IFN-stimulated genes (ISGs) that are highly upregulated following viral infection and have been identified as potential restrictors of alphaviruses. The mechanism by which IFIT1 restricts RNA viruses is dependent on self and non-self-discrimination of RNA, and alphaviruses evade this recognition via their 5' untranslated region (UTR). However, the role of IFIT2 during alphavirus replication and the mechanism of viral replication inhibition is unclear. In this study, we identify IFIT2 as a restriction factor for Venezuelan equine encephalitis virus (VEEV) and show that IFIT2 binds the 3' 3'UTR of the virus. We investigated the potential role of variability in the 3'UTR of the virus affecting IFIT2 antiviral activity by studying infection with VEEV. Comparison of recombinant VEEV clones containing 3'UTR sequences derived from epizootic and enzootic isolates exhibited differential sensitivity to IFIT2 restriction in vitro infection studies, suggesting that the alphavirus 3'UTR sequence may function in part to evade IFIT2 restriction. In vitro binding assays demonstrate that IFIT2 binds to the VEEV 3'UTR; however, in contrast to previous studies, VEEV restriction did not appear to be dependent on the ability of IFIT2 to inhibit translation of viral RNA, suggesting a novel mechanism of IFIT2 restriction. Our study demonstrates that IFIT2 is a restriction factor for alphaviruses and variability in the 3'UTR of VEEV can modulate viral restriction by IFIT2. Ongoing studies are exploring the biological consequences of IFIT2-VEEV RNA interaction in viral pathogenesis and defining sequence and structural features of RNAs that regulate IFIT2 recognition.

Short 5' UTRs serve as a marker for viral mRNA translation inhibition by the IFIT2-IFIT3 antiviral complex

Recognition of "non-self" nucleic acids, including cytoplasmic dsDNA, dsRNA, or mRNAs lacking proper 5' cap structures, is critical for the innate immune response to viruses. Here, we demonstrate that short 5' untranslated regions (UTRs), a characteristic of many viral mRNAs, can also serve as a molecular pattern for innate immune recognition via the interferon-induced proteins IFIT2 and IFIT3. The IFIT2-IFIT3 heterodimer, formed through an intricate domain swap structure resolved by cryo-EM, mediates viral mRNA 5' end recognition, translation inhibition, and ultimately antiviral activity. Critically, 5' UTR lengths <50 nucleotides are necessary and sufficient to sensitize an mRNA to translation inhibition by the IFIT2-IFIT3 complex. Accordingly, diverse viruses whose mRNAs contain short 5' UTRs, such as vesicular stomatitis virus and parainfluenza virus 3, are sensitive to IFIT2-IFIT3-mediated antiviral activity. Our work thus reveals a pattern of antiviral nucleic acid immune recognition that takes advantage of the inherent constraints on viral genome size.

Curcumin Derivatives in Medicinal Chemistry: Potential Applications in Cancer Treatment

Curcumin, a naturally occurring compound found in the rhizome of Curcuma plants, particularly in turmeric (Curcuma longa L.), exhibits a broad range of biological activities, including anti-inflammatory, antioxidant, and anticancer properties. Curcumin has demonstrated effectiveness in inhibiting tumor growth, arousing interest for its potential in treating various cancers, such as breast, lung, prostate, and brain cancers. However, the clinical application of curcumin is limited due to its low chemical stability, poor water solubility, and low bioavailability. In response to these challenges, structural modifications of curcumin have been explored to improve its pharmacological properties, including enhanced anticancer selectivity index and bioavailability. This review highlights promising chemical modifications of curcumin that could lead to the development of more effective anticancer therapies. By functionalizing the parent curcumin molecule, researchers aim to create more stable and bioavailable compounds with enhanced therapeutic potential, making curcumin derivatives promising candidates for medical applications.

Targeting the TRIM14/USP14 Axis Enhances Immunotherapy Efficacy by Inducing Autophagic Degradation of PD-L1

Immunotherapy has greatly improved cancer treatment in recent years by harnessing the immune system to target cancer cells. The first immunotherapeutic agent approved by the FDA was IFNα. Treatment with IFNα can lead to effective immune activation and attenuate tumor immune evasion, but persistent treatment has been shown to elicit immunosuppressive effects. Here, we identified an autophagy-dependent mechanism by which IFNα triggers tumor immune evasion by upregulating PD-L1 to suppress the antitumor activity of CD8+ T cells. Mechanistically, IFNα increased the transcription of TRIM14, which recruited the deubiquitinase USP14 to inhibit the autophagic degradation of PD-L1. USP14 removed K63-linked ubiquitin chains from PD-L1, impairing its recognition by the cargo receptor p62 (also known as SQSTM1) for subsequent autophagic degradation. Combining the USP14 inhibitor IU1 with IFNα and anti-CTLA4 treatment effectively suppressed tumor growth without significant toxicity. This work suggests a strategy for targeting selective autophagy to abolish PD-L1-mediated cancer immune evasion. Significance: IFNα-induced TRIM14 transcription suppresses antitumor immunity by recruiting USP14 to inhibit autophagic degradation of PD-L1, indicating that targeting this axis could be an effective immunotherapeutic approach for treating cancer.

Targeting Peroxisome Proliferator-Activated Receptor-β/δ, Reactive Oxygen Species and Redox Signaling with Phytocompounds for Cancer Therapy

Significance: Peroxisome proliferator-activated receptors (PPARs) have a moderately preserved amino-terminal domain, an extremely preserved DNA-binding domain, an integral hinge region, and a distinct ligand-binding domain that are frequently encountered with the other nuclear receptors. PPAR-β/δ is among the three nuclear receptor superfamily members in the PPAR group. Recent Advances: Emerging studies provide an insight on natural compounds that have gained increasing attention as potential anticancer agents due to their ability to target multiple pathways involved in cancer development and progression. Critical Issues: Modulation of PPAR-β/δ activity has been suggested as a potential therapeutic strategy for cancer management. This review focuses on the ability of bioactive phytocompounds to impact reactive oxygen species (ROS) and redox signaling by targeting PPAR-β/δ for cancer therapy. The rise of ROS in cancer cells may play an important part in the initiation and progression of cancer. However, excessive levels of ROS stress can also be toxic to the cells and cancer cells with increased oxidative stress are likely to be more vulnerable to damage by further ROS insults induced by exogenous agents, such as phytocompounds and therapeutic agents. Therefore, redox modulation is a way to selectively kill cancer cells without causing significant toxicity to normal cells. However, use of antioxidants together with cancer drugs may risk the effect of treatment as both act through opposite mechanisms. Future Directions: It is advisable to employ more thorough and detailed methodologies to undertake mechanistic explorations of numerous phytocompounds. Moreover, conducting additional clinical studies is recommended to establish optimal dosages, efficacy, and the impact of different phytochemicals on PPAR-β/δ.

IFIT1 modulates the proliferation, migration and invasion of pancreatic cancer cells via Wnt/β-catenin signaling

OBJECTIVES

Previously, Interferon-induced Protein with Tetratricopeptide Repeats 1 (IFIT1) has been shown to promote cancer development. Here, we aimed to explore the role of IFIT1 in the development and progression of pancreatic cancer, including the underlying mechanisms.

METHODS

We explored IFIT1 expression in pancreatic cancer samples using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Cell Counting Kit-8 (CCK8), colony formation, scratch wound-healing and Transwell assays were performed to assess the proliferation, migration and invasion abilities of pancreatic cancer cells. Gene Set Enrichment Analysis (GSEA) and Western blotting were performed to assess the regulatory effect of IFIT1 on the Wnt/β-catenin pathway.

RESULTS

We found that upregulation of IFIT1 expression is common in pancreatic cancer and is negatively associated with overall patient survival. Knockdown of IFIT1 expression led to decreased proliferation, migration and invasion of pancreatic cancer cells. We also found that IFIT1 could regulate Wnt/β-catenin signaling, and that a Wnt/β-catenin agonist could reverse this effect. In addition, we found that IFIT1 can promote epithelial-mesenchymal transition (EMT) of pancreatic cancer cells.

CONCLUSIONS

Our data indicate that IFIT1 increases pancreatic cancer cell proliferation, migration and invasion by activating the Wnt/β-catenin pathway. In addition, we found that EMT could be regulated by IFIT1. IFIT1 may serve as a potential therapeutic target for pancreatic cancer.

Multiple Genes with Potential Tumor Suppressive Activity Are Present on Chromosome 10q Loss in Neuroblastoma and Are Associated with Poor Prognosis

Neuroblastoma (NB) is a tumor affecting the peripheral sympathetic nervous system that substantially contributes to childhood cancer mortality. Despite recent advances in understanding the complexity of NB, the mechanisms determining its progression are still largely unknown. Some recurrent segmental chromosome aberrations (SCA) have been associated with poor survival. However, the prognostic role of most SCA has not yet been investigated. We examined a cohort of 260 NB primary tumors at disease onset for the loss of chromosome 10q, by array-comparative genomic hybridization (a-CGH) and Single Nucleotide Polymorphism (SNP) array and we found that 26 showed 10q loss, while the others 234 displayed different SCA. We observed a lower event-free survival for NB patients displaying 10q loss compared to patients with tumors carrying other SCA. Furthermore, analyzing the region of 10q loss, we identified a cluster of 75 deleted genes associated with poorer outcome. Low expression of six of these genes, above all CCSER2, was significantly correlated to worse survival using in silico data from 786 NB patients. These potential tumor suppressor genes can be partly responsible for the poor prognosis of NB patients with 10q loss.

Curcumin activates NLRC4, AIM2, and IFI16 inflammasomes and induces pyroptosis by up-regulated ISG3 transcript factor in acute myeloid leukemia cell lines

Curcumin, the primary bioactive component isolated from turmeric, has been found to possess a variety of biological functions, including anti-leukemia activity. However, the effect of curcumin in different leukemia cells vary. In this study, we demonstrated that curcumin induced the expression of AIM2, IFI16, and NLRC4 inflammasomes in leukemia cells U937 by increasing the expression levels of ISG3 transcription factor complex, which activated caspase 1, promoted cleavage of GSDMD, and induced pyroptosis. We also found that pyroptosis executor GSDMD was not expressed in two curcumin-insensitive cells HL60 and K562 cells. In addition, exogenous overexpression of GSDMD by lentiviral transduction in K562 cells increased the anti-cancer activity of curcumin, and inhibiting the expression of GSDMD by shRNA enhanced U937 cells to resist curcumin. The results showed that inducing pyroptosis is a novel mechanism underlying the anti-leukemia effects of curcumin.

Knockdown of G1P3 inhibits cell proliferation and enhances the cytotoxicity of dexamethasone in acute lymphoblastic leukemia

Drug resistance contributes to treatment failure and relapse in acute lymphoblastic leukemia (ALL). G1P3 (also known as IFI6, interferon, alpha-inducible protein 6) has been regarded as an antiapoptotic protein in myeloma cells and contributes to chemoresistance in breast cancer. However, the role of G1P3 in the proliferation and chemosensitivity of ALL is largely unknown. Data from colony formation and bromo-deoxyuridine (BrdU) incorporation assays showed that siRNA-mediated downregulation of G1P3 repressed cell proliferation of glucocorticoids-resistant human leukemic cells (CEM-C1), while overexpression of G1P3 promoted the cell proliferation. Cell apoptosis of CEM-C1 was suppressed by G1P3 overexpression accompanied by a decrease in cleaved caspase-3 and caspase-9. Knockdown of G1P3 increased protein expression of cleaved caspase-3 and caspase-9 to promote the cell apoptosis of CEM-C1. Moreover, silencing of G1P3 reduced cell viability and promoted cell apoptosis of CEM-C1 exposed to dexamethasone. The proapoptotic protein B-cell lymphoma 2 interacting mediator of cell death (Bim) was enhanced by the interference of G1P3 in CEM-C1. Silencing of Bim attenuated G1P3 interference-induced decrease in cell viability and increase in cell apoptosis in CEM-C1 exposed to dexamethasone. Conclusively, knockdown of G1P3 inhibited cell proliferation of ALL and sensitized glucocorticoid-resistant ALL cells to dexamethasone through upregulation of Bim-mediated cell apoptosis.

IFIT1 modulates the proliferation, migration and invasion of pancreatic cancer cells via Wnt/β-catenin signaling

OBJECTIVES

Previously, Interferon-induced Protein with Tetratricopeptide Repeats 1 (IFIT1) has been shown to promote cancer development. Here, we aimed to explore the role of IFIT1 in the development and progression of pancreatic cancer, including the underlying mechanisms.

METHODS

We explored IFIT1 expression in pancreatic cancer samples using The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets. Cell Counting Kit-8 (CCK8), colony formation, scratch wound-healing and Transwell assays were performed to assess the proliferation, migration and invasion abilities of pancreatic cancer cells. Gene Set Enrichment Analysis (GSEA) and Western blotting were performed to assess the regulatory effect of IFIT1 on the Wnt/β-catenin pathway.

RESULTS

We found that upregulation of IFIT1 expression is common in pancreatic cancer and is negatively associated with overall patient survival. Knockdown of IFIT1 expression led to decreased proliferation, migration and invasion of pancreatic cancer cells. We also found that IFIT1 could regulate Wnt/β-catenin signaling, and that a Wnt/β-catenin agonist could reverse this effect. In addition, we found that IFIT1 can promote epithelial-mesenchymal transition (EMT) of pancreatic cancer cells.

CONCLUSIONS

Our data indicate that IFIT1 increases pancreatic cancer cell proliferation, migration and invasion by activating the Wnt/β-catenin pathway. In addition, we found that EMT could be regulated by IFIT1. IFIT1 may serve as a potential therapeutic target for pancreatic cancer.

Putative role of natural products as Protein Kinase C modulator in different disease conditions

INTRODUCTION

Protein kinase C (PKC) is a promising drug target for various therapeutic areas. Natural products derived from plants, animals, microorganisms, and marine organisms have been used by humans as medicine from prehistoric times. Recently, several compounds derived from plants have been found to modulate PKC activities through competitive binding with ATP binding site, and other allosteric regions of PKC. As a result fresh race has been started in academia and pharmaceutical companies to develop an effective naturally derived small-molecule inhibitor to target PKC activities. Herein, in this review, we have discussed several natural products and their derivatives, which are reported to have an impact on PKC signaling cascade.

METHODS

All information presented in this review article regarding the regulation of PKC by natural products has been acquired by a systematic search of various electronic databases, including ScienceDirect, Scopus, Google Scholar, Web of science, ResearchGate, and PubMed. The keywords PKC, natural products, curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, protocatechuic acid, tannic acid, PKC modulators from marine organism, bryostatin, staurosporine, midostaurin, sangivamycin, and other relevant key words were explored.

RESULTS

The natural products and their derivatives including curcumin, rottlerin, quercetin, ellagic acid, epigallocatechin-3 gallate, ingenol 3 angelate, resveratrol, bryostatin, staurosporine, and midostaurin play a major role in the management of PKC activity during various disease progression.

CONCLUSION

Based on the comprehensive literature survey, it could be concluded that various natural products can regulate PKC activity during disease progression. However, extensive research is needed to circumvent the challenge of isoform specific regulation of PKC by natural products.

FAM64A is an androgen receptor-regulated feedback tumor promoter in prostate cancer

Endocrine therapy for prostate cancer (PCa) mainly inhibits androgen receptor (AR) signaling, due to increased androgen synthesis and AR changes, PCa evolved into castration-resistant prostate cancer (CRPC). The function of Family With Sequence Similarity 64 Member A (FAM64A) and its association with prostate cancer has not been reported. In our research, we first reported that FAM64A is up-regulated and positively associated with poor prognosis of patients with prostate cancer (PCa) by TCGA database and immunohistochemistry staining. Moreover, knockdown of FAM64A significantly suppressed the proliferation, migration, invasion, and cell cycle of PCa cells in vitro. Mechanistically, FAM64A expression was increased by dihydrotestosterone (DHT) through direct binding of AR to FAM64A promoter, and notably promoted the proliferation, migration, invasion, and cell cycle of androgen-dependent cell line of PCa. In addition, abnormal expression of FAM64A affects the immune and interferon signaling pathway of PCa cells. In conclusion, FAM64A was up-regulated by AR through directly binding to its specific promoter region to promote the development of PCa, and was associated with the immune mechanism and interferon signaling pathway, which provided a better understanding and a new potential for treating PCa.

Senescent Colon and Breast Cancer Cells Induced by Doxorubicin Exhibit Enhanced Sensitivity to Curcumin, Caffeine, and Thymoquinone

Cellular senescence is a process of physiological growth arrest that can be induced by intrinsic or extrinsic stress signals. Some cancer therapies are associated with senescence of cancer cells with a typical cell cycle arrest. Doxorubicin (Dox) induces senescence by a p53-dependent pathway and telomere dysfunction of numerous cancers. However, cellular senescence induces suppression in proliferation activity, and these cells will remain metabolically active and play an important role in tumor relapse and development of drug resistance. In the current study, we investigated the apoptotic effect of curcumin (Cur), caffeine (Caff), and thymoquinone (TQ) on senescent colon cancer HCT116 and breast cancer MCF7 cell lines treated with Dox. Results showed typical senescence markers including decreased bromodeoxyuridine incorporation, increased accumulation of senescence-associated β-galactosidase (SA-β-gal), cell cycle arrest, and upregulation of p53, P-p53, and p21 proteins. Annexin-V analysis by flow cytometry revealed 2- to 6-fold increases in annexin-V–positive cells in Dox-treated MCF7 and HCT116 cells by Cur (15 µM), Caff (10 mM), and TQ (50 µM; P < .001). In comparison between proliferative and senescent of either HCT116 or MCF7 cells, Caff at 15 mM and TQ at 25 µM induced significant increases in apoptosis of Dox-treated cells compared with proliferative cells (P < .001). Data revealed that Cur, Caff, and TQ potentially induced apoptosis of both proliferative and senescent HCT116 and MCF7 cells. In vivo and clinical trials are of great importance to validate this result.

SAHA Overcomes 5-FU Resistance in IFIT2-Depleted Oral Squamous Cell Carcinoma Cells

Simple Summary

IFIT2 depletion is associated with increased epithelial-mesenchymal transition and metastasis. The main aim of our study was to understand the link between drug resistance and IFIT2 depletion. In this study, we confirmed resistance to multiple common therapeutic drugs, particularly 5-FU, which showed especially high resistance in IFIT2-depleted cells. Interestingly, combination of SAHA and 5-FU overcame 5-FU resistance in IFIT2-depleted cells. Hence, our findings suggest that IFIT2 expression may be used as a biomarker to decide whether to undergo 5-FU treatment, but also the SAHA and 5-FU combination may be a potential new treatment regimen to augment 5-FU therapy in patients with thymidylate synthase-mediated drug-resistant oral squamous cell carcinoma.

Abstract

Interferon-induced protein with tetratricopeptide repeats 2 (IFIT2) is a member of the interferon-stimulated gene family that contains tetratricopeptide repeats (TPRs), which mediate protein–protein interactions in various biological systems. We previously showed the depletion of IFIT2 enhanced cell migration and metastatic activity in oral squamous cell carcinoma (OSCC) cells via the activation of atypical PKC signaling. In this study, we found that IFIT2-knockdown cells displayed higher resistance to 5-fluorouracil (5-FU) than control cells. The comet assay and annexin V analysis showed decreased DNA damage and cell death in IFIT2-knockdown cells compared to control cells treated with 5-FU. Cell cycle progression was also perturbed by 5-FU treatment, with the accumulation of IFIT2-depleted cells in S phase in a time-dependent manner. We further observed the overexpression of thymidylate synthase (TS) and thymidine kinase (TK) in IFIT2-knockdown cells. Inhibition of TS alone or double inhibition of TS and TK1 using the siRNA technique increased susceptibility to 5-FU in IFIT2-knockdown cells. We further identified that suberanilohydroxamic acid (SAHA) treatment decreased the expression of TS in IFIT2-knockdown cells and demonstrated that pretreatment with SAHA sensitized IFIT2-knockdown cells to 5-FU in vitro and in vivo. In conclusion, IFIT2 knockdown enhances TS expression, which mediates 5-FU resistance, and SAHA pretreatment suppresses TS expression and hence sensitizes cells to 5-FU. SAHA will be an effective strategy for the treatment of OSCC patients with 5-FU resistance.

Emerging Role of Integrative Medicine in Hematologic Malignancies: a Literature Review and Update on Current Trends in Complementary Medical Practices in Hematologic Cancers

PURPOSE OF REVIEW

This review discusses the emerging role of integrative hematology. It reinforces the growing interest of CAM among patients, and the importance of provider knowledge and participation in discussions with patients about the subject. The main question asked in this review, "Is there evidence for the use of integrative medicine practices in the field of malignant hematology?" is answered by examining current research and providing relevant summaries.

RECENT FINDINGS

Data suggests that practices such as meditative movement, exercise, nutrition and supplements and touch therapy can be used for symptom alleviation, preventive measures, and novel treatment development. Integrative hematology is a needed part of complete patient care, and it is the role of providers to be knowledgeable and open to ensure patients are engaging in practices that are evidence-informed and safe. More studies are needed in the field in order to make concrete and robust recommendations.

Modulation of dysregulated cancer metabolism by plant secondary metabolites: A mechanistic review

Several signaling pathways and basic metabolites are responsible for the control of metabolism in both normal and cancer cells. As emerging hallmarks of cancer metabolism, the abnormal activities of these pathways are of the most noticeable events in cancer. This altered metabolism expedites the survival and proliferation of cancer cells, which have attracted a substantial amount of interest in cancer metabolism. Nowadays, targeting metabolism and cross-linked signaling pathways in cancer has been a hot topic to investigate novel drugs against cancer. Despite the efficiency of conventional drugs in cancer therapy, their associated toxicity, resistance, and high-cost cause limitations in their application. Besides, considering the numerous signaling pathways cross-linked with cancer metabolism, discovery, and development of multi-targeted and safe natural compounds has been a high priority. Natural secondary metabolites have exhibited promising anticancer effects by targeting dysregulated signaling pathways linked to cancer metabolism. The present review reveals the metabolism and cross-linked dysregulated signaling pathways in cancer. The promising therapeutic targets in cancer, as well as the critical role of natural secondary metabolites for significant anticancer enhancements, have also been highlighted to find novel/potential therapeutic agents for cancer treatment.

Overexpression of IFIT2 inhibits the proliferation of chronic myeloid leukemia cells by regulating the BCR‑ABL/AKT/mTOR pathway

Chronic myeloid leukemia (CML) is a myeloproliferative disorder that accounts for ~10% of all newly diagnosed leukemia cases. Early diagnosis is essential for long‑term beneficial outcomes. The present study observed that interferon‑induced protein with tetratricopeptde repeats 2 (IFIT2) expression levels were reduced in bone marrow samples from CML patients compared with control samples using RNA sequencing and reverse transcription‑PCR. IFIT2 expression levels were restored in patients treated with tyrosine kinase inhibitors. To investigate the effect of IFIT2 on CML patients, a stable IFIT2 expressing K562 cell line was established. It was demonstrated that IFIT2 overexpression in K562 cells inhibits cell proliferation and arrests the cell cycle at the G1 phase. In addition, it was demonstrated by western blotting that IFIT2 inhibits the BCR‑ABL oncoprotein and regulates its downstream AKT/mTOR signaling pathway. IFIT2 could induce cell cycle arrest‑associated gene p27kip1 by degrading cullin1‑mediated E3 ligases. In summary, the present study demonstrated that IFIT2 was efficacious in inhibiting CML and is a potential therapeutic target.

Emerging Functions of Human IFIT Proteins in Cancer

Interferon-induced protein with tetratricopeptide repeats (IFIT) genes are prominent interferon-stimulated genes (ISGs). The human IFIT gene family consists of four genes named IFIT1, IFIT2, IFIT3, and IFIT5. The expression of IFIT genes is very low in most cell types, whereas their expression is greatly enhanced by interferon treatment, viral infection, and pathogen-associated molecular patterns (PAMPs). The proteins encoded by IFIT genes have multiple tetratricopeptide repeat (TPR) motifs. IFIT proteins do not have any known enzymatic roles. However, they execute a variety of cellular functions by mediating protein-protein interactions and forming multiprotein complexes with cellular and viral proteins through their multiple TPR motifs. The versatile tertiary structure of TPR motifs in IFIT proteins enables them to be involved in distinct biological functions, including host innate immunity, antiviral immune response, virus-induced translation initiation, replication, double-stranded RNA signaling, and PAMP recognition. The current understanding of the IFIT proteins and their role in cellular signaling mechanisms is limited to the antiviral immune response and innate immunity. However, recent studies on IFIT protein functions and their involvement in various molecular signaling mechanisms have implicated them in cancer progression and metastasis. In this article, we focused on critical molecular, biological and oncogenic functions of human IFIT proteins by reviewing their prognostic significance in health and cancer. Research suggests that IFIT proteins could be novel therapeutic targets for cancer therapy.

Re: A Meta-Analysis of the Clinical Use of Curcumin for Irritable Bowel Syndrome

We read with interest the article by Ng et al [...].

Synergistic Cytotoxicity of Methyl 4-Hydroxycinnamate and Carnosic Acid to Acute Myeloid Leukemia Cells via Calcium-Dependent Apoptosis Induction

Acute myeloid leukemia (AML) is a malignant hematopoietic disease with poor prognosis for most patients. Conventional chemotherapy has been the standard treatment approach for AML in the past 40 years with limited success. Although, several targeted drugs were recently approved, their long-term impact on survival of patients with AML is yet to be determined. Thus, it is still necessary to develop alternative therapeutic approaches for this disease. We have previously shown a marked synergistic anti-leukemic effect of two polyphenols, curcumin (CUR) and carnosic acid (CA), on AML cells in-vitro and in-vivo. In this study, we identified another phenolic compound, methyl 4-hydroxycinnamate (MHC), which among several tested phytochemicals could uniquely cooperate with CA in killing AML cells, but not normal peripheral blood mononuclear cells. Notably, our data revealed striking phenotypical and mechanistic similarities in the apoptotic effects of MHC+CA and CUR+CA on AML cells. Yet, we show that MHC is a non-fluorescent molecule, which is an important technical advantage over CUR that can interfere in various fluorescence-based assays. Collectively, we demonstrated for the first time the antileukemic activity of MHC in combination with another phenolic compound. This type of synergistically acting combinations may represent prototypes for novel antileukemic therapy.

Better together: the role of IFIT protein-protein interactions in the antiviral response

The interferon-induced proteins with tetratricopeptide repeats (IFITs) are a family of antiviral proteins conserved throughout all vertebrates. IFIT1 binds tightly to non-self RNA, particularly capped transcripts lacking methylation on the first cap-proximal nucleotide, and inhibits their translation by out-competing the cellular translation initiation apparatus. This exerts immense selection pressure on cytoplasmic RNA viruses to maintain mechanisms that protect their messenger RNA from IFIT1 recognition. However, it is becoming increasingly clear that protein-protein interactions are necessary for optimal IFIT function. Recently, IFIT1, IFIT2 and IFIT3 have been shown to form a functional complex in which IFIT3 serves as a central scaffold to regulate and/or enhance the antiviral functions of the other two components. Moreover, IFITs interact with other cellular proteins to expand their contribution to regulation of the host antiviral response by modulating innate immune signalling and apoptosis. Here, we summarize recent advances in our understanding of the IFIT complex and review how this impacts on the greater role of IFIT proteins in the innate antiviral response.

Curcumin inhibits the growth of liver cancer stem cells through the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

Cancer stem cells are considered as a main cause of cancer recurrence. In the present study, the effects of curcumin on the growth of liver cancer stem cells (LCSCs) were investigated. The proliferation and apoptosis of LCSCs were assessed by MTT assays and flow cytometry. Changes in the expression of apoptosis-related proteins were identified by western blotting. The results of the study demonstrated that curcumin treatment inhibited the growth of LCSCs, induced cell apoptosis, as well as regulated the expression of apoptosis-associated proteins and the release of cytochrome c. Further experiments revealed that treatment with curcumin inhibited that the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. Treatment with an activator of PI3K/AKT reversed the curcumin-induced growth inhibition of LCSCs. These results demonstrated that curcumin inhibited the growth of LCSCs through the PI3K/AKT/mTOR signaling pathway. Thus, the present study suggested that curcumin may be a potentially efficient agent in the treatment of liver cancer.