Decursin chemosensitizes human multiple myeloma cells through inhibition of STAT3 signaling pathway

Decursin induces FLT3-ITD acute myeloid leukemia cell apoptosis by increasing the expression of the ubiquitin-conjugase UBE2L6

Mutation in the internal tandem duplication sequence of the FLT3 gene (FLT3-ITD) is linked to a poor clinical prognosis in acute myeloid leukemia (AML) patients. FLT3 inhibitors have demonstrated efficacy in improving the prognosis of AML patients with FLT3-ITD. However, the efficacy of FLT3 inhibitors is short-lived, and is often limited by secondary drug resistance when used alone. Recent investigations have provided an innovative approach for treating FLT3-ITD AML by targeting FLT3 protein degradation. Our study revealed that decursin selectively impaired the viability of FLT3-ITD-positive AML cells. Subsequent analysis revealed that decursin preferentially induced cell cycle arrest and apoptosis in FLT3-ITD-positive AML cells through proteasome-mediated FLT3-ITD degradation. Further research revealed that decursin significantly increased the expression of UBE2L6, an e2-conjugating enzyme that degrades FLT3-ITD. Downregulation of UBE2L6 by small hairpin RNA (shRNA) reduced decursin-induced FLT3-ITD-linked apoptosis and degradation. The anti-FLT3-ITD AML effect of decursin was also validated in cell lines and patient-derived mouse models. Moreover, decursin synergistically enhanced venetoclax-induced apoptosis.

Natural linear coumarin-heterocyclic conjugates: A review of their roles in phytotherapy

Heterocycle conjugates provide a fresh investigative scope to find novel molecules with enhanced phytotherapeutic characteristics. Coumarin-based products are widely used in the synthesis of several compounds with biological and medicinal properties since they are naturally occurring heterocycles with a broad dispersion. The investigation of coumarin-based phytochemicals with annulated heterocyclic rings is a promising approach to discovering novel conjugates with significant phytotherapeutic attributes. Due to the applicable coumarin extraction processes, a range of linear coumarin-heterocyclic conjugates were isolated from different natural resources and exhibited remarkable therapeutic efficacy. This review highlights the phytotherapeutic potential and origins of various natural linear coumarin-heterocyclic conjugates. We searched several databases, including Science Direct, Web of Science, Springer, Google Scholar, and PubMed. After sieving, we ultimately identified and included 118 pertinent studies published between 2000 and the middle of 2023. This will inspire medicinal chemists with extremely insightful ideas for designing and synthesizing therapeutically active lead compounds in the future that are built on the pharmacophores of coumarin-heterocyclic conjugates and have significant therapeutic attributes.

Targeting YAP1 to improve the efficacy of immune checkpoint inhibitors in liver cancer: mechanism and strategy

Liver cancer is the third leading of tumor death, including hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Immune checkpoint inhibitors (ICIs) are yielding much for sufferers to hope for patients, but only some patients with advanced liver tumor respond. Recent research showed that tumor microenvironment (TME) is critical for the effectiveness of ICIs in advanced liver tumor. Meanwhile, metabolic reprogramming of liver tumor leads to immunosuppression in TME. These suggest that regulating the abnormal metabolism of liver tumor cells and firing up TME to turn "cold tumor" into "hot tumor" are potential strategies to improve the therapeutic effect of ICIs in liver tumor. Previous studies have found that YAP1 is a potential target to improve the efficacy of anti-PD-1 in HCC. Here, we review that YAP1 promotes immunosuppression of TME, mainly due to the overstimulation of cytokines in TME by YAP1. Subsequently, we studied the effects of YAP1 on metabolic reprogramming in liver tumor cells, including glycolysis, gluconeogenesis, lipid metabolism, arachidonic acid metabolism, and amino acid metabolism. Lastly, we summarized the existing drugs targeting YAP1 in the treatment of liver tumor, including some medicines from natural sources, which have the potential to improve the efficacy of ICIs in the treatment of liver tumor. This review contributed to the application of targeted YAP1 for combined therapy with ICIs in liver tumor patients.

A comprehensive review of the anticancer effects of decursin

Cancer is a globally complex disease with a plethora of genetic, physiological, metabolic, and environmental variations. With the increasing resistance to current anticancer drugs, efforts have been made to develop effective cancer treatments. Currently, natural products are considered promising cancer therapeutic agents due to their potent anticancer activity and low intrinsic toxicity. Decursin, a coumarin analog mainly derived from the roots of the medicinal plant Angelica sinensis, has a wide range of biological activities, including anti-inflammatory, antioxidant, neuroprotective, and especially anticancer activities. Existing studies indicate that decursin affects cell proliferation, apoptosis, autophagy, angiogenesis, and metastasis. It also indirectly affects the immune microenvironment and can act as a potential anticancer agent. Decursin can exert synergistic antitumor effects when used in combination with a number of common clinical anticancer drugs, enhancing chemotherapy sensitivity and reversing drug resistance in cancer cells, suggesting that decursin is a good drug combination. Second, decursin is also a promising lead compound, and compounds modifying its structure and formulation form also have good anticancer effects. In addition, decursin is not only a key ingredient in several natural herbs and dietary supplements but is also available through a biosynthetic pathway, with anticancer properties and a high degree of safety in cells, animals, and humans. Thus, it is evident that decursin is a promising natural compound, and its great potential for cancer prevention and treatment needs to be studied and explored in greater depth to support its move from the laboratory to the clinic.

Chiral separation and molecular modeling study of decursinol and its derivatives using polysaccharide-based chiral stationary phases

Plant-based bioactive substances have long been used to treat inflammatory ailments, owing to their low toxicity and cost-effectiveness. To enhance plant treatment by eliminating undesirable isomers, optimizing the chiral separation techniques in pharmaceutical and clinical studies is important. This study reported a simple and effective method for chiral separation of decursinol and its derivatives, which are pyranocoumarin compounds with anti-cancer and anti-inflammatory properties. Baseline separation (Rs >1.5) was achieved using five different polysaccharide-based chiral stationary phases (CSPs) that differed in chiral origin, chiral selector chemistry, and preparation technique. To separate all six enantiomers simultaneously, n-hexane and three alcohol modifiers (ethanol, isopropanol, and n-butanol) were used as mobile phases in the normal-phase mode. The chiral separation ability of each column with various mobile phase compositions was compared and discussed. As a result, amylose-based CSPs with linear alcohol modifiers demonstrated superior resolution. Three cases of elution order reversal caused by modifications of CSPs and alcohol modifiers were observed and thoroughly analyzed. To elucidate the chiral recognition mechanism and enantiomeric elution order (EEO) reversal phenomenon, detailed molecular docking simulations were conducted. The R- and S-enantiomers of decursinol, epoxide, and CGK012 exhibited binding energies of -6.6, -6.3, -6.2, -6.3, -7.3, and -7.5 kcal/mol, respectively. The magnitude of the difference in binding energies was consistent with the elution order and enantioselectivity (α) of the analytes. The molecular simulation results demonstrated that hydrogen bonds, π-π interactions, and hydrophobic interactions have a significant impact on chiral recognition mechanisms. Overall, this study presented a novel and logical approach of optimizing chiral separation techniques in the pharmaceutical and clinical industries. Our findings could be further applied for screening and optimizing enantiomeric separation.

Decursin inhibits EGFR-ERK1/2 signaling axis in advanced human prostate carcinoma cells

We have shown that decursin, a coumarin compound, induces cell cycle arrest and apoptosis in human prostate cancer cells (PCa); however, its molecular mechanisms are largely unexplored. We studied the mechanisms associated with its anticancer activity in advanced human prostate carcinoma cells. We found that decursin inhibited epidermal growth factor receptor (EGFR) signaling by inhibiting its activating phosphorylation at tyrosine 1068 residue in DU145 and 22Rv1 cells. This inhibition of EGFR was associated with the downregulation of ERK1/2 phosphorylation. Both EGFR and ERK1/2 are known to be deregulated/activated in many human malignancies. Consistent with our earlier study, decursin (25-100 µM) treatment for 24-72 h inhibited DU145 cell proliferation by 49%-87% (p < 0.001) which was associated with strong G1 phase arrest and cell death. It also decreased (p < 0.001) the number of surviving colonies. Decursin moderately increased the expression of Rb-related proteins p107 and p130 but decreased the levels of E2F family transcription factors including E2F-3, E2F-4 and E2F-5. Further, decursin strongly inhibited the growth of androgen-dependent prostate carcinoma 22Rv1 cells from 61% to 79% (p < 0.001) and arrested these cells at G1 phase via induction of cyclin-dependent kinase inhibitor p27/Kip1 and downregulation of CDK2 and CDK4 protein expression. Additionally, EGFR inhibitor erlotinib- and EGF ligand-modulated EGFR activation validated EGFR signaling as a target of decursin-mediated cell growth inhibition and cytotoxicity. Decursin decreased EGF ligand-induced phosphorylation of EGFR (Y-1068) as well as activation of its downstream mediator, ERK1/2. Furthermore, inhibitory targeting of EGFR-ERK1/2 axis by combinatorial treatment of decursin and erlotinib further sensitized DU145 cells for the decursin-induced growth inhibition and cell death. Overall, these findings strongly suggest that anticancer efficacy of decursin against human PCa involves inhibitory targeting of EGFR-ERK1/2 signaling axis, a pathway constitutively active in advanced PCa.

Meta analysis of bioactive compounds, miRNA, siRNA and cell death regulators as sensitizers to doxorubicin induced chemoresistance

Cancer has presented to be the most challenging disease, contributing to one in six mortalities worldwide. The current treatment regimen involves multiple rounds of chemotherapy administration, alone or in combination. The treatment has adverse effects including cardiomyopathy, hepatotoxicity, and nephrotoxicity. In addition, the development of resistance to chemo has been attributed to cancer relapse and low patient overall survivability. Multiple drug resistance development may be through numerous factors such as up-regulation of drug transporters, drug inactivation, alteration of drug targets and drug degradation. Doxorubicin is a widely used first line chemotherapeutic drug for a myriad of cancers. It has multiple intracellular targets, DNA intercalation, adduct formation, topoisomerase inhibition, iron chelation, reactive oxygen species generation and promotes immune mediated clearance of the tumor. Agents that can sensitize the resistant cancer cells to the chemotherapeutic drug are currently the focus to improve the clinical efficiency of cancer therapy. This review summarizes the recent 10-year research on the use of natural phytochemicals, inhibitors of apoptosis and autophagy, miRNAs, siRNAs and nanoformulations being investigated for doxorubicin chemosensitization.

A novel aryl-guanidinium derivative, VP79s, targets the signal transducer and activator of transcription 3 signaling pathway, downregulates myeloid cell leukaemia-1 and exhibits preclinical activity against multiple myeloma

AIMS

We have recently described a novel guanidinium-based compound, VP79s, which induces cytotoxicity in various cancer cell lines. Here, we aim to investigate the activity of VP79s and associated mechanisms of action in multiple myeloma (MM) cells in vitro and ex vivo.

MAIN METHODS

The effects of VP79s on cell viability and induction of apoptosis was examined in a panel of drug-sensitive and drug-resistant MM cell lines, as well as ex vivo patient samples and normal donor lymphocytes and platelets. Cell signaling pathways associated with the biological effects of VP79s were analysed by immunoblotting and flow cytometry. Gene expression changes were assessed by quantitative real-time PCR analysis.

KEY FINDINGS

VP79s was found to rapidly inhibit both constitutively active and IL-6-induced STAT3 signaling with concurrent downregulation of the IL-6 receptors, CD130 and CD126. VP79s induced a rapid and dose-dependent downregulation of anti-apoptotic Bcl-2 family member, myeloid cell leukaemia-1 (MCL-1). VP79s enhanced bortezomib induced cell death and was also found to overcome bone marrow stromal cell induced drug resistance. VP79s exhibited activity in ex vivo patient samples at concentrations which had no effect on peripheral blood mononuclear cells, lymphocytes and platelets isolated from healthy donors.

SIGNIFICANCE

As VP79s resulted in rapid inhibition of the key IL-6/STAT3 signaling pathway and downregulation of MCL-1 expression with subsequent selective anti-myeloma activity, VP79s may be a potential therapeutic agent with a novel mechanism of action in MM cells.

Arctiin is a pharmacological inhibitor of STAT3 phosphorylation at tyrosine 705 residue and potentiates bortezomib-induced apoptotic and anti-angiogenic effects in human multiple myeloma cells

BACKGROUND

Arctiin is a main component from the fruits of Arctium lappa L., that can be prescribed for cold or flu in East Asian countries; it has also been found to exert chemopreventive actions against various tumor cells.

HYPOTHESIS

In view of this evidence, we examined arctiin for its ability to trigger apoptosis and inhibit the activation of signal transducer and activator of transcription 3 (STAT3) in human multiple myeloma (MM) cells.

METHODS

We evaluated the effect of arctiin on STAT3 signaling cascades and its regulated functional responses in MM cells.

RESULTS

Arctiin effectively blocked the constitutive activation of STAT3 phosphorylation in the residue of tyrosine 705. Arctiin also abrogated the constitutive activation of Src phosphorylation and Janus-activated kinases (JAKs) 1/2. Furthermore, it was found that arctiin treatment clearly enhanced the mRNA and protein levels of protein tyrosine phosphatase ε (PTPε), and the silencing of PTPε caused a reversal of the arctiin-induced PTPε expression and the blockadge of STAT3 phosphorylation. Interestingly, arctiin could not repress IL-6-induced STAT3 activation in serum-starved U266 cells and when arctiin was incubated with a complete culture medium in RPMI 8226 and MM.1S cells. Arctiin suppressed cell proliferation, accumulated cells in the G2/M cell-cycle phase, and induced apoptosis within U266 cells, although the knockdown of PTPε prevented PARP cleavage and caspase-3 activation induced by the arctiin. In addition, arctiin exerted cytotoxicity in MM cells, but did not do so in peripheral blood mononuclear cells. Arctiin down-modulated diverse oncogenic gene products regulated by STAT3, although the induction of apoptosis by arctiin was abrogated upon transfection with pMXs-STAT3C in mouse embryonic fibroblast (MEF) cells. Arctiin also potentiated bortezomib-induced antitumor effects in U266 cells.

CONCLUSION

On the whole, our results indicate that arctiin is a potentially new inhibitor of constitutive STAT3 activation through the induction of PTPε in MM, cells and therefore has great value in treating various tumors sheltering constitutively activated STAT3.

Kinase inhibitors as potential agents in the treatment of multiple myeloma

Recent years have witnessed a dramatic increase in the number of therapeutic options available for the treatment of multiple myeloma (MM) - from immunomodulating agents to proteasome inhibitors to histone deacetylase (HDAC) inhibitors and, most recently, monoclonal antibodies. Used in conjunction with autologous hematopoietic stem cell transplantation, these modalities have nearly doubled the disease's five-year survival rate over the last three decades to about 50%. In spite of these advances, MM still is considered incurable as resistance and relapse are common. While small molecule protein kinase inhibitors have made inroads in the therapy of a number of cancers, to date their application to MM has been less than successful. Focusing on MM, this review examines the roles played by a number of kinases in driving the malignant state and the rationale for target development in the design of a number of kinase inhibitors that have demonstrated anti-myeloma activity in both in vitro and in vivo xenograph models, as well as those that have entered clinical trials. Among the targets and their inhibitors examined are receptor and non-receptor tyrosine kinases, cell cycle control kinases, the PI3K/AKT/mTOR pathway kinases, protein kinase C, mitogen-activated protein kinase, glycogen synthase kinase, casein kinase, integrin-linked kinase, sphingosine kinase, and kinases involved in the unfolded protein response.

Natural Korean Medicine Dang-Gui: Biosynthesis, Effective Extraction and Formulations of Major Active Pyranocoumarins, Their Molecular Action Mechanism in Cancer, and Other Biological Activities

Angelica gigas Nakai (AGN) is a crucial oriental medicinal herb that grows especially in Korea and the Far-East countries. It contains chemically active compounds like pyranocoumarins, polyacetylenes and essential oils, which might be useful for treatment of several chronic diseases. It has been used for centuries as a traditional medicine in Southeast Asia, but in Western countries is used as a functional food and a major ingredient of several herbal products. The genus Angelica is also known as ‘female ginseng’ due to its critical therapeutic role in female afflictions, such as gynecological problems. However, it is well-documented that the AGN pyranocoumarins may play vital beneficial roles against cancer, neurodisorders, inflammation, osteoporosis, amnesia, allergies, depression, fungi, diabetes, ischemia, dermatitis, reactive oxygen species (ROS) and androgen. Though numerous studies revealed the role of AGN pyranocoumarins as therapeutic agents, none of the reviews have published their molecular mechanism of action. To the best of our knowledge, this would be the first review that aims to appraise the biosynthesis of AGN’s major active pyranocoumarins, discuss effective extraction and formulation methods, and detail the molecular action mechanism of decursin (D), decursinol angelate (DA) and decursinol (DOH) in chronic diseases, which would further help extension of research in this area.

Decursin and decursinol angelate: molecular mechanism and therapeutic potential in inflammatory diseases

Epidemiological studies have shown that inflammation plays a critical role in the development and progression of various chronic diseases, including cancers, neurological diseases, hepatic fibrosis, diabetic retinopathy, and vascular diseases. Decursin and decursinol angelate (DA) are pyranocoumarin compounds obtained from the roots of Angelica gigas. Several studies have described the anti-inflammatory effects of decursin and DA. Decursin and DA have shown potential anti-inflammatory activity by modulating growth factors such as vascular endothelial growth factor, transcription factors such as signal transducer and activator of transcription 3 and nuclear factor kappa-light-chain-enhancer of activated B cells, cellular enzymes including matrix metalloproteinases cyclooxygenase, and protein kinases such as extracellular receptor kinase, phosphatidylinositol-3-kinase, and protein kinase C. These compounds have the ability to induce apoptosis by activating pro-apoptotic proteins and the caspase cascade, and reduced the expression of anti-apoptotic proteins such as B-cell lymphoma 2 and B-cell lymphoma-extra-large. Interaction with multiple molecular targets and cytotoxic effects, these two compounds are favorable candidates for treating various chronic inflammatory diseases such as cancers (prostate, breast, leukemia, cervical, and myeloma), rheumatoid arthritis, diabetic retinopathy, hepatic fibrosis, osteoclastogenesis, allergy, and Alzheimer's disease. We have summarized the preliminary studies regarding the biological effects of decursin and DA. In this review, we will also highlight the functions of coumarin compounds that can be translated to a clinical practice for the treatment and prevention of various inflammatory ailments.

Preparation and characterization of lipid nanoparticle/pDNA complexes for STAT3 downregulation and overcoming chemotherapy resistance in lung cancer cells

Developments in the field of molecular oncology have revealed that resistance to chemotherapeutics is acqured through several mechanisms including overexpression of common oncogenic proteins. Signal Transducer and Activator of Transcription 3 (STAT3) is one of these oncogenes that is overexpressed in many cancer types. RNA interference (RNAi) is proven powerful tool for downregulating STAT3, allowing re-sensitization of resistant cancer cells. However, delivery of RNA interference-mediating molecules for STAT3 downregulation in lung cancer cells is limited to a small number of studies most of which employ commercially available transfection kits. The aim of this study was to develop and evaluate cationic solid lipid nanoparticles for delivery of RNAi-mediating plasmid DNA in order to down regulate STAT3 in cisplatin resistant lung cancer cells. We focused on obtaining cSLN:plasmid DNA complexes with size below or equal to 100nm, and a positive zeta potential. Two successful candidate cSLN:plasmid DNA complexes (K2 and K3) were selected for in vitro tests and cell culture studies. These formulations have particle sizes of 98 and 93nm, and zeta potential values of 10.5 and 8.9mV, respectively. Plasmid DNA in these complexes was protected against DNaseI and serum-mediated degradation. Substantial part of DNA retained its supercoiled and circular conformation. TEM images showed nearly spherical complex structure. Both formulations reduced STAT3 expression by approx. 5-fold in cisplatin resistant Calu1 cell line and increased the sensitivity of cells to cisplatin.

Capillarisin inhibits constitutive and inducible STAT3 activation through induction of SHP-1 and SHP-2 tyrosine phosphatases

Signal transducers and activators of transcription (STAT)-3 is a latent cytosolic transcription factor that has been closely associated with survival, proliferation, chemoresistance, and metastasis of tumor cells. Whether the anti-proliferative, pro-apoptotic, and anti-metastatic effects of capillarisin (CPS), derived from Artemisia capillaris (Compositae), are linked to its capability to inhibit STAT3 activation was investigated. We found that CPS specifically inhibited both constitutive and inducible STAT3 activation at tyrosine residue 705 but not at serine residue 727 in human multiple myeloma cells. Besides the inhibition of STAT3 phosphorylation, CPS also abrogated STAT3 constitutive activity and nuclear translocation. The suppression of STAT3 was mediated through the inhibition of activation of upstream JAK1, JAK2, and c-Src kinases. Treatment with the protein tyrosine phosphatase (PTP) inhibitor pervanadate treatment reversed the CPS-induced down-regulation of JAK1/2 and STAT3, thereby suggesting the involvement of a PTP. Indeed, knockdown of the SHP-1 and SHP-2 genes by small interfering RNA suppressed the ability of CPS to inhibit JAK1 and STAT3 activation, suggesting the critical role of both SHP-1 and SHP-2 in its possible mechanism of action. CPS downregulated the expression of STAT3-regulated antiapoptotic and proliferative gene products; and this correlated with suppression of cell viability, the accumulation of cells in sub-G1 phase of cell cycle and induction of apoptosis. Moreover, CPS potentiated bortezomib-induced apoptotic effects in MM cells, and this correlated with down-regulation of various gene products that mediate cell proliferation (Cyclin D1 and COX-2), cell survival (Bcl-2, Bcl-xl, IAP1, IAP2, and Survivin), invasion (MMP-9), and angiogenesis (VEGF). Thus, overall, our results suggest that CPS is a novel blocker of STAT3 activation and thus may have a potential in negative regulation of growth, metastasis, and chemoresistance of tumor cells.

Cancer Prevention and Therapy: Integrating Traditional Korean Medicine Into Modern Cancer Care

In spite of billions of dollars spent on cancer research each year, overall cancer incidence and cancer survival has not changed significantly in the last half century. Instead, the recent projection from the World Health Organization suggests that global cancer incidence and death is expected to double within the next decade. This requires an "out of the box" thinking approach. While traditional medicine used for thousands of years is safe and affordable, its efficacy and mechanism of action are not fully reported. Demonstrating that traditional medicine is efficacious and how it works can provide a "bed to bench" and "bench to bed" back approach toward prevention and treatment of cancer. This current review is an attempt to describe the contributions of traditional Korean medicine (TKM) to modern medicine and, in particular, cancer treatment. TKM suggests that cancer is an outcome of an imbalance of body, mind, and spirit; thus, it requires a multimodal treatment approach that involves lifestyle modification, herbal prescription, acupuncture, moxibustion, traditional exercise, and meditation to restore the balance. Old wisdoms in combination with modern science can find a new way to deal with the "emperor of all maladies."

Decursin and Doxorubicin Are in Synergy for the Induction of Apoptosis via STAT3 and/or mTOR Pathways in Human Multiple Myeloma Cells

Background. Combination cancer therapy is one of the attractive approaches to overcome drug resistance of cancer cells. In the present study, we investigated the synergistic effect of decursin from Angelica gigas and doxorubicin on the induction of apoptosis in three human multiple myeloma cells. Methodology/Principal Findings. Combined treatment of decursin and doxorubicin significantly exerted significant cytotoxicity compared to doxorubicin or decursin in U266, RPMI8226, and MM.1S cells. Furthermore, the combination treatment enhanced the activation of caspase-9 and -3, the cleavage of PARP, and the sub G1 population compared to either drug alone in three multiple myeloma cells. In addition, the combined treatment downregulated the phosphorylation of mTOR and its downstream S6K1 and activated the phosphorylation of ERK in three multiple myeloma cells. Furthermore, the combined treatment reduced mitochondrial membrane potential, suppressed the phosphorylation of JAK2, STAT3, and Src, activated SHP-2, and attenuated the expression of cyclind-D1 and survivin in U266 cells. Conversely, tyrosine phosphatase inhibitor pervanadate reversed STAT3 inactivation and also PARP cleavage and caspase-3 activation induced by combined treatment of doxorubicin and decursin in U266 cells. Conclusions/Significance. Overall, the combination treatment of decursin and doxorubicin can enhance apoptotic activity via mTOR and/or STAT3 signaling pathway in multiple myeloma cells.

Antitumor effects of Stat3-siRNA and endostatin combined therapies, delivered by attenuated Salmonella, on orthotopically implanted hepatocarcinoma

Hepatocellular carcinoma (HCC) is one of the most aggressive carcinomas. Limited therapeutic options, mainly due to a fragmented genetic understanding of HCC, and major HCC resistance to conventional chemotherapy are the key reasons for a poor prognosis. Thus, new effective treatments are urgent and gene therapy may be a novel option. Signal transducer and activator of transcription 3 (Stat3) is a highly studied member of the STAT family. Inhibition of Stat3 signaling has been found to suppress tumor growth and improve survival, providing a molecular target for cancer therapy. Furthermore, HCC is a hypervascular tumor and angiogenesis plays a crucial role in tumor growth and metastasis. Thus, anti-angiogenic therapy, combined with inhibition of Stat3, may be an effective approach to combat HCC. We tested the effect that the combination therapy consisting of endostatin (a powerful angiogenesis inhibitor) and Stat3-specific small interfering RNA, using a DNA vector delivered by attenuated S. typhimurium, on an orthotopic HCC model in C57BL/6 mice. Although antitumor effects were observed with either single therapeutic treatment, the combination therapy provided superior antitumor effects. Correlated with this finding, the combination treatment resulted in significant alteration of Stat3 and endostatin levels and that of the downstream gene VEGF, decreased cell proliferation, induced cell apoptosis and inhibited angiogenesis. Importantly, combined treatment also elicited immune system regulation of various immune cells and cytokines. This study has provided a novel cancer gene therapeutic approach.

Interrelationship and expression profiling of cyclooxygenase and angiogenic factors in Indian patients with multiple myeloma

Multiple myeloma (MM) is classically illustrated by a desynchronized cytokine system with rise in inflammatory cytokines. There are recent reports which emphasized the potential role of angiogenesis in the development of MM. Role of cyclooxygenase 2 (COX-2) is well documented in the pathogenesis of solid tumors, but little is known about its occurrence and function in hematologic neoplasms. Involvement of neoangiogenesis is reported in the progression of MM, and angiopoietins probably contribute to this progression by enhancing neovascularization. Circulatory and mRNA levels of angiogenic factors and cyclooxygenase were determined in 125 subjects (75 MM patients and 50 healthy controls) by using enzyme-linked immunosorbent assay and quantitative PCR. We observed significant increase for angiogenic factors (Ang-1, Ang-2, hepatocyte growth factor, and vascular endothelial growth factor) and cyclooxygenase at circulatory level, as well as at mRNA level, as compared to healthy controls except insignificant increase for Ang-1 at circulatory level. We have also observed the significant positive correlation of all angiogenic factors with cyclooxygenase. The strong association found between angiogenic factors and COX-2 in this study may lead to the development of combination therapeutic strategy to treat MM. Therefore, targeting COX-2 by using its effective inhibitors demonstrating antiangiogenic and antitumor effects could be used as a new therapeutic approach for treatment of MM.