Curcumin Inhibits the Growth of Hepatocellular Carcinoma via the MARCH1-mediated Modulation of JAK2/STAT3 Signaling

BACKGROUND

Curcumin has been reported to have anti-hepatocellular carcinoma (HCC) effects, but the underlying mechanism is not well known.

OBJECTIVES

To investigate whether membrane-associated RING-CH 1 (MARCH1) is involved in the curcumin-induced growth suppression in HCC and its underlying molecular mechanism. A few recent patents for curcumin for cancer are also reviewed in this article.

METHODS

The effect of curcumin on growth inhibition of HCC cells was analyzed through in vitro and in vivo experiments, and the expression levels of MARCH1, Bcl-2, VEGF, cyclin B1, cyclin D1, and JAK2/STAT3 signaling molecules were measured in HCC cells and the xenograft tumors in nude mice. Cell transfection with MARCH1 siRNAs or expression plasmid was used to explore the role of MARCH1 in the curcumin-induced growth inhibition of HCC cells.

RESULTS

Curcumin inhibited cell proliferation, promoted apoptosis, and arrested the cell cycle at the G2/M phase in HCC cells with the decrease of Bcl-2, VEGF, cyclin B1, and cyclin D1 expression as well as JAK2 and STAT3 phosphorylation, resulting in the growth suppression of HCC cells. MARCH1 is highly expressed in HCC cells, and its expression was downregulated after curcumin treatment in a dose-dependent manner. The knockdown of MARCH1 by siRNA decreased the phosphorylation levels of JAK2 and STAT3 and inhibited the growth of HCC cells. In contrast, opposite results were observed when HCC cells overexpressed MARCH1. A xenograft tumor model in nude mice also showed that curcumin downregulated MARCH1 expression and decelerated the growth of transplanted HCC with the downregulation of JAK2/STAT3 signaling and functional molecules. The ADC value of MRI analysis showed that curcumin slowed down the progression of HCC.

CONCLUSION

Our results demonstrated that curcumin may inhibit the activation of JAK2/STAT3 signaling pathway by downregulating MARCH1 expression, resulting in the growth suppression of HCC. MARCH1 may be a novel target of curcumin in HCC treatment.

SHP-1/STAT3 Interaction Is Related to Luteolin-Induced Myocardial Ischemia Protection

Prevention and management of myocardial ischemia/reperfusion (I/R) injury is a key step in coronary heart disease surgery. Luteolin is a falconoid compound that has an antioxidant effect, but its mechanism in I/R injury in vivo and in vitro is still under explored. This study attempted to reveal the role of luteolin (Lut) in I/R through mediation of the Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1)/Signal transducer and activator of transcription 3 (STAT3) pathway. To establish I/R rat models, the left anterior descending artery (LAD) was ligated for 30 min and re-perfused for 1 h in Lut-pretreated or nude rats. Comparisons between infarct area, cardiac dysfunction, and myocardial cell death and inflammatory reaction were performed in I/R-induced rats. Hypoxia/reoxygenation (H/R) cell models were established by stimulating H9c2 cells with 95% nitrogen and 5% carbon dioxide. Simultaneously, H/R-related cell death and inflammatory reactions were investigated following Lut treatment. The target protein of Lut was identified using western blotting. Pro-inflammatory cytokines were also measured in serum or Lut-pretreated cell culture medium. The results revealed that compared with the I/R group, Lut treatment could significantly decrease myocardial infarction (MI) area, increase left ventricular ejection fraction (LVEF), and decrease cell death and pro-inflammatory cytokines in the serum. Decreased apoptosis and inflammatory cytokines were also observed in H/R cells after Lut treatment. Lut treatment downregulated SHP-1 expression and subsequently upregulated STAT3 phosphorylation in both I/R rat heart tissue and H9c2 cells. The findings of the current study suggest that Lut can protect the heart and reduce MI area, cell apoptosis rate, and inflammatory level in I/R models.

Discovery and Validation of Nitroxoline as a Novel STAT3 Inhibitor in Drug-resistant Urothelial Bladder Cancer

Repeated cycles of first-line chemotherapy drugs such as doxorubicin (DOX) and cisplatin (CIS) trigger frequent chemoresistance in recurrent urothelial bladder cancer (UBC). Nitroxoline (NTX), an antibiotic to treat urinary tract infections, has been recently repurposed for cancer treatment. Here we aimed to investigate whether NTX suppresses drug-resistant UBC and its molecular mechanism. The drug-resistant cell lines T24/DOX and T24/CIS were established by continual exposure of parental cell line T24 to DOX and CIS, respectively. T24/DOX and T24/CIS cells were resistant to DOX and CIS, respectively, but they were sensitive to NTX time- and dose-dependently. Overexpressions of STAT3 and P-glycoprotein (P-gp) were identified in T24/DOX and T24/CIS, which could be reversed by NTX. Western blot revealed that NTX downregulated p-STAT3, c-Myc, Cyclin D1, CDK4, CDK6, Bcl-xL, Mcl-1, and Survivin, which were further confirmed by Stattic, a selective STAT3 inhibitor. In vivo, NTX exhibited the significant anti-tumor effect in T24/DOX and T24/CIS tumor-bearing mice. These results suggested that NTX-induced P-gp reversal, G0/G1 arrest, and apoptosis in drug-resistant UBC were mediated by inhibition of STAT3 signaling. Our findings repurpose NTX as a novel STAT3 inhibitor to induce P-gp reversal, G0/G1 arrest, and apoptosis in drug-resistant UBC.

6-Gingerol inhibits proliferation in gastric cancer via the STAT3 pathway in vitro

With high incidence and mortality, gastric cancer seriously threatened human's life. It is arduous and necessary to investigate its pathogenesis and dig effective drugs. In this study, we explored the role of 6-Gingerol (GI), a natural active ingredient, in treating gastric cancer cells. MTT assay and colony formation assay were utilized to confirmed that GI can control the proliferation of gastric cancer cells, which is time and concentration-dependent to some extent. The Annexin V-FITC/PI staining results by flow cytometry reveal that GI induces the apoptosis of gastric cancer cells. And a study on further pathways by western blot shows that GI brings about cell apoptosis by inhibiting the activation of STAT3. GI therefore may be a good candidate for treating gastric cancer.

Dual radiosensitization and anti-STAT3 anti-proliferative strategy based on delivery of gold nanoparticle - oligonucleotide nanoconstructs to head and neck cancer cells

Constitutively activated signal transducer and activator of transcription 3 (STAT3) factor is an important therapeutic target in head and neck cancer (HNC). Despite early promising results, a reliable systemic delivery system for STAT3- targeted oligonucleotide (ODN) drugs is still needed for future clinical translation of anti-STAT3 therapies. We engineered and tested a novel ODN duplex/gold nanoparticle (AuNP)-based system carrying a therapeutic STAT3 decoy (STAT3d) payload. This strategy is two-pronged because of the additive STAT3 antagonism and radiosensitizing properties of AuNP. The specificity to head and neck cancer cell surface was imparted by using a nucleolin aptamer (NUAP) that was linked to AuNP for taking the advantage of an aberrant presentation of a nuclear protein nucleolin on the cell surface. STAT3d and nucleolin aptamer constructs were independently linked to AuNPs via Au-S bonds. The synthesized AuNP constructs (AuNP-NUAP-STAT3d) exhibited internalization in cells that was quantified by using radiolabeled STAT3d. AuNP-NUAP-STAT3d showed radiosensitizing effect in human HNC FaDu cell culture experiments that resulted in an increase of cell DNA damage as determined by measuring γ-H2AX phosphorylation levels by flow cytometry. The radiosensitization study also demonstrated that AuNP-NUAP-STAT3d as well as STAT3d alone resulted in the efficient inhibition of A431 cell proliferation. While FaDu cells did not show instant proliferation inhibition after incubating with AuNP-NUAP-STAT3d, the cell DNA damage in these cells showed nearly a 50% increase in AuNP-NUAP-STAT3d group after treating with radiation. Compared with anti-EGFR humanized antibody (Cetuximab), AuNP-NUAP-STAT3d system had an overall stronger radiosensitization effect in both A431 and FaDu cells.

AKR1C1 Activates STAT3 to Promote the Metastasis of Non-Small Cell Lung Cancer

Metastasis is the leading cause of mortality for human non-small cell lung cancer (NSCLC). However, it is difficult to target tumor metastasis because the molecular mechanisms underlying NSCLC invasion and migration remain unclear. Methods: GEO data analyses and IHC analyses were performed to identify that the expression level of AKR1C1, a member of human aldo-keto reductase family, was highly elevated in patients with metastasis or metastatic foci of NSCLC patients. Functional analyses (in vitro and in vivo) and quantitative genomic analyses were preformed to confirm the pro-metastatic effects of AKR1C1 and the underlying mechanisms. The correlation of AKR1C1 with the prognosis of NSCLC patients was evaluated using Kaplan-Meier analyses. Results: in NSCLC patients, AKR1C1 expression was closely correlated with the metastatic potential of tumors. AKR1C1 overexpression in nonmetastatic cancer cells significantly promoted metastasis both in vitro and in vivo, whereas depletion of AKR1C1 in highly metastatic tumors potently alleviated these effects. Quantitative genomic and functional analyses revealed that AKR1C1 directly interacted with STAT3 and facilitated its phosphorylation-thus reinforcing the binding of STAT3 to the promoter regions of target genes-and then transactivated these genes, which ultimately promoted tumor metastasis. Further studies showed that AKR1C1 might facilitate the interaction of STAT3 with its upstream kinase JAK2. Intriguingly, AKR1C1 exerted these pro-metastatic effects in a catalytic-independent manner. In addition, a significant correlation between AKR1C1 and STAT3 pathway was observed in the metastatic foci of NSCLC patients, and the AKR1C1-STAT3 levels were highly correlated with a poor prognosis in NSCLC patients. Conclusions: taken together, we show that AKR1C1 is a potent inducer of NSCLC metastasis. Our study uncovers the active function of AKR1C1 as a key component of the STAT3 pathway, which promotes lung cancer metastasis, and highlights a candidate therapeutic target to potentially improve the survival of NSCLC patients with metastatic disease.

Evaluation of STAT3 rs1053004 single nucleotide polymorphism in patients with chronic hepatitis B and hepatocellular carcinoma

Chronic infection with hepatitis B (CHB) virus is one of the most important risk factors for Hepatocellular carcinoma (HCC). Hepatitis B virus (HBV) causes liver cancer in various ways. One of these ways is increasing the expression of the signal transducer and activator of transcription 3 (STAT3) in Hepatocytes by HBV. The purpose of this research is to evaluate the single nucleotide polymorphism (SNP) rs1053004 in the STAT3 gene in CHB patients and individuals who suffer from HCC. In this research, 33 patients CHB-related HCC, 50 patients infected with chronic hepatitis B infection (CHB) without HCC and 50 healthy individuals were investigated for the presence of rs1053004 in the STAT3 gene according to the PCR-based differentiation of alleles test. Data analysis presented a different and significant distribution of alleles and genotypes (p<0.05). When the HCC and CHB groups were compared from the point of the frequency of alleles, the frequency of the C allele and CC genotype in the HCC group were higher CHB and control groups. Analysis of our data in the genotype model (CC vs. TT + TC) showed, this meaningful relationship remained between the HCC group and the three groups of CHB, healthy and all controls. These results illustrate that perhaps rs1053004 polymorphisms in the STAT3 gene participated in the progression of hepatitis B to HCC in Iranian people.

Fluorocarbons Enhance Intracellular Delivery of Short STAT3-sensors and Enable Specific Imaging

Short oligonucleotide sequences are now being widely investigated for their potential therapeutic properties. The modification of oligonucleotide termini with short fluorinated residues is capable of drastically altering their behavior in complex in vitro and in vivo systems, and thus may serve to greatly enhance their therapeutic potential. The main goals of our work were to explore: 1) how modification of STAT3 transcription factor-binding oligodeoxynucleotide (ODN) duplexes (ODND) with one or two short fluorocarbon (FC)-based residues would change their properties in vitro and in vivo, and if so, how this would affect their intracellular uptake by cancer cells, and 2) the ability of such modified ODND to form non-covalent complexes with FC-modified carrier macromolecule. The latter has an inherent advantage of producing a ¹⁹F-specific magnetic resonance (MR) imaging signature. Thus, we also tested the ability of such copolymers to generate ¹⁹F-MR signals. Materials and Methods. Fluorinated nucleic acid residues were incorporated into ODN by using automated synthesis or via activated esters on ODN 5'-ends. To quantify ODND uptake by the cells and to track their stability, we covalently labeled ODN with fluorophores using internucleoside linker technology; the FC-modified carrier was synthesized by acylation of pegylated polylysine graft copolymer with perfluoroundecanoic acid (M5-gPLL-PFUDA). Results. ODN with a single FC group exhibited a tendency to form duplexes with higher melting points and with increased stability against degradation when compared to control non-modified ODNs. ODND carrying fluorinated residues showed complex formation with M5-gPLL-PFUDA as predicted by molecular dynamics simulations. Moreover, FC groups modulated the specificity of ODND binding to the STAT3 target. Finally, FC modification resulted in greater cell uptake (2 to 4 fold higher) when compared to the uptake of non-modified ODND as determined by quantitative confocal fluorescence imaging of A431 and INS-1 cells. Conclusion. ODND modification with FC residues enables fine-tuning of protein binding specificity to double-strand binding motifs and results in an increased internalization by A431 and INS-1 cells in culture. Our results show that modification of ODN termini with FC residues is both a feasible and powerful strategy for developing more efficient nucleic acid-based therapies with the added benefit of allowing for non-invasive MR imaging of ODND therapeutic targeting and response.