Fung-Jou Lu

Background: Curcumin, a dietary polyphenol with anticancer potential, has been reported to enhance the efficacy of chemotherapeutic agents. Methods: The effects of combined curcumin and doxorubicin treatment on apoptosis and associated signaling pathways were investigated in human osteosarcoma HOS cells. Results: Combined treatment significantly reduced cell viability and induced apoptotic morphological changes, which were confirmed by increased sub-G1 population, enhanced DNA fragmentation, and elevated cleaved poly(ADP-ribose) polymerase (PARP) levels. Mechanistically, combined treatment markedly increased c-Jun N-terminal kinase (JNK) phosphorylation, whereas extracellular signal-regulated kinase (ERK) phosphorylation showed no appreciable change. Pharmacological inhibition revealed that JNK suppression attenuated PARP cleavage, while ERK inhibition also reduced apoptotic responses, suggesting a permissive role of basal ERK activity. In addition, combined treatment was associated with increased expression of the endoplasmic reticulum stress marker GRP78 and modulation of autophagy-associated markers. Although thioredoxin domain-containing protein 5 (TXNDC5) expression was reduced, TXNDC5 overexpression failed to attenuate apoptosis, indicating that apoptosis induction occurs independently of TXNDC5. Conclusions: These findings indicate that combined curcumin and doxorubicin induce apoptosis primarily through JNK-dependent MAPK signaling, accompanied by stress-associated cellular responses.

Piperine, a phytochemical alkaloid, exhibits notable anticancer properties in several cancer cell types. In this study, we investigated the mechanisms by which piperine induces cell death and apoptosis in colorectal cancer (CRC) cells, focusing on oxidative stress and key signaling pathways. Using MTT assay, flow cytometry, gene overexpression, and Western blot analysis, we observed that piperine significantly reduced cell viability, triggered G1 phase cell cycle arrest, and promoted apoptosis in DLD-1 cells. In addition, piperine effectively suppressed cell viability and induced apoptosis in other CRC cell lines, including SW480, HT-29, and Caco-2 cells. These effects were associated with increased intracellular reactive oxygen species (ROS) generation, mediated by the regulation of mitochondrial complex III, NADPH oxidase, and xanthine oxidase. Additionally, piperine modulated signaling pathways by inhibiting phosphoinositide 3-kinase (PI3K)/Akt, activating p38 and p-extracellular signal-regulated kinase (ERK). Pretreatment with antimycin A, apocynin, allopurinol, and PD98059, and the overexpression of p-Akt significantly recovered cell viability and reduced apoptosis, confirming the involvement of these pathways. This study is the first to demonstrate piperine induces apoptosis in CRC cells through a multifaceted oxidative stress mechanism and by critically modulating PI3K/Akt and ERK signaling pathways.

Piperine, a phytochemical alkaloid, exhibits anticancer properties on several cancer cells. The present study explored the important oxidative stress and signaling mechanisms by which piperine provokes cell death and apoptosis in colorectal DLD-1 cancer cells. We investigated the cell viability, cell cycle, and apoptosis-inducing of piperine by performing MTT assay, flow cytometry, gene overexpression, and Western blot analysis. Piperine treatment of DLD-1 cells diminished cell viability, and stimulated cell cycle G1 arrest and apoptosis. Piperine induced intracellular reactive oxygen species (ROS) generation by regulating mitochondrial complex III, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, and xanthine oxidase. Piperine inhibited the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) pathway and activated the p-38 and p-extracellular signal-regulated kinase (ERK) pathways. Pretreatment with antimycin A (a mitochondrial complex III inhibitor), apocynin (an NADPH oxidase inhibitor), allopurinol (a xanthine oxidase inhibitor), and PD98059 (an ERK inhibitor) and the overexpression of p-Akt significantly recovered cell viability and reduced apoptosis. This study was the first to demonstrate a multiple oxidative stress mechanism and the critical regulating PI3K/Akt and ERK signaling pathways of piperine, inducing apoptosis on colorectal cancer cells.

In this study, we discovered the mechanisms underlying parecoxib and resveratrol combination’s anti-cancer characteristics against human colorectal cancer DLD-1 cells. We studied its anti-proliferation and apoptosis-provoking effect by utilizing cell viability 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, fluorescence microscope, gene overexpression, Western blot, and flow cytometry analyses. Parecoxib enhanced the ability of resveratrol to inhibit cell viability and increase apoptosis. Parecoxib in combination with resveratrol strongly enhanced apoptosis by inhibiting the expression of thioredoxin domain containing 5 (TXNDC5) and Akt phosphorylation. Parecoxib enhanced resveratrol-provoked c-Jun N-terminal kinase (JNK) and p38 phosphorylation. Overexpression of TXNDC5 and repression of JNK and p38 pathways significantly reversed the inhibition of cell viability and stimulation of apoptosis by the parecoxib/resveratrol combination. This study presents evidence that parecoxib enhances the anti-cancer power of resveratrol in DLD-1 colorectal cancer cells via the inhibition of TXNDC5 and Akt signaling and enhancement of JNK/p38 MAPK pathways. Parecoxib may be provided as an efficient drug to sensitize colorectal cancer by resveratrol.

Colorectal cancer is one of the most common causes of cancer mortality worldwide, and innovative drugs for the treatment of colorectal cancer are continually being developed. 5-Fluorouracil (5-FU) is a common clinical chemotherapeutic drug. Acquired resistance to 5-FU is a clinical challenge in colorectal cancer treatment. Parecoxib is a selective COX-2-specific inhibitor that was demonstrated to inhibit metastasis in colorectal cancers in our previous study. This study aimed to investigate the synergistic antimetastatic activities of parecoxib to 5-FU in human colorectal cancer cells and determine the underlying mechanisms. Parecoxib and 5-FU synergistically suppressed metastasis in colorectal cancer cells. Treatment with the parecoxib/5-FU combination induced an increase in E-cadherin and decrease in β-catenin expression. The parecoxib/5-FU combination inhibited MMP-9 activity, and the NF-κB pathway was suppressed as well. Mechanistic analysis denoted that the parecoxib/5-FU combination hindered the essential molecules of the PI3K/Akt route to obstruct metastatic colorectal cancer. Furthermore, the parecoxib/5-FU combination could inhibit reactive oxygen species. Our work showed the antimetastatic capacity of the parecoxib/5-FU combination for treating colorectal cancers via the targeting of the PI3K/Akt/NF-κB pathway.

Colorectal cancer is one of the most common causes of cancer mortality worldwide, and innovative drugs for the treatment of colorectal cancer are continually being revealed. 5-Fluorouracil (5-FU) is a common clinical chemotherapeutic drug. Acquired resistance to 5-FU is a clinical challenge in colorectal cancer. Parecoxib is a selective COX-2-specific inhibitor, which has been demonstrated to inhibit metastasis in colorectal cancers in our previous study. This study aimed to investigate the synergistic antimetastatic activities of parecoxib to 5-FU in human colorectal cancer cells and determine the underlying mechanism. parecoxib and 5-FU synergistically suppressed metastasis in colorectal cancer cells. Treatment with the parecoxib /5-FU combination induced an increase in E-cadherin and decrease in β-catenin. The parecoxib/5-FU combination could inhibit MMP-9 and MMP-2 expression and MMP-9 activity, and the NF-κB pathway might be suppressed as well. Mechanistic analysis denoted that the parecoxib/5-FU combination hindered the essential molecules of the PI3K/Akt route to obstruct metastatic colorectal cancer. Furthermore, the parecoxib/5-FU combination could inhibit reactive oxygen species. Our work showed the antimetastatic capacity of the parecoxib/5-FU combination for colorectal cancers via targeting the PI3K/Akt /NF-κB pathway.

(1) Background: Temozolomide (TMZ), an oral alkylating agent, is used to treat malignant gliomas and other difficult-to-treat tumors. TMZ can enter the cerebrospinal fluid p.o. (per os) and does not need hepatic metabolism for activation of its use as a standard chemotherapeutic regimen after surgical resection of malignant glioma of the brain. However, the prognosis remains poor for most patients, and the survival rate is still unsatisfactory. Gallic acid (Ga) is a secondary metabolite existent in numerous plants. Ga shows various bioactivities, including antioxidant, anti-inflammatory, anticancer and antimicrobial effects. In this study, the latent enhanced anti-cancer efficacy of Ga in TMZ-treated U87MG cells (a human glioma line) was evaluated. (2) Methods: The U87MG cell line was cultured for 24 h. The cells were incubated with Ga alone, TMZ alone, or their combination for various time points. Cell viability and the drug combination index were evaluated by an XTT-based analysis and isobologram analysis, respectively. DNA destruction and intracellular reactive oxygen species (ROS) generation were analyzed by flow cytometer. The expression of various proteins was assessed via Western blotting. (3) Results: Compared with the action of TMZ alone or Ga alone, TMZ/Ga combination augmented the inhibition of cellular viability and apoptotic level in the U87MG glioma cell line. This enhanced anti-cancer effect correlated with the decreased expression of Bcl-2 and p-Akt, and corresponded with the activation of the p38 mitogen-activated protein kinase (MAPK) pathway. In addition, Ga suppressed the TMZ-promoted ROS generation. (4) Conclusions: Ga can augment the anti-cancer effect of TMZ via the repression of Bcl-2 expression and Akt activation and the enhancement of the p38 MAPK pathway. Our results offer a novel probable approach for the medical treatment of malignant glioma.

AIM: To investigate the anti-fibrosis effect of rosmarinic acid (RA) in pterygium epithelial cells (PECs) to determine if RA is a potent agent for treating pterygium. METHODS: The PECs (1x10(4) cells/mL) were treated with 100 mu mol/L of RA for 1, 3 and 6h. After RA treatment, the cell viability was determined by staining with acridine orange/DAPI and analysis via a NucleoCounter NC-3000. The protein expression levels of type I collagen, transforming growth factor beta-1 (TGF-beta 1), TGF-beta type II receptor (TGF-beta RII), p-Smad1/5, p-Smad2, p-Smad3, and Smad4 of the cell lysates were measured by Western blot analysis. RESULTS: The cell viability of PECs was significantly decreased after RA treatment (P<0.01). As the result, RA reduced the protein expression of type I collagen and TGF-beta 1 of PECs. Additionally, RA also inhibited TGF-beta 1/Smad signaling by decreasing the protein expressions of TGF-beta RII, p-Smad1/5, p-Smad2, p-Smad3, and Smad4. CONCLUSION: This study demonstrate that RA could inhibit fibrosis of PECs by down-regulating type I collagen expression and TGF-beta 1/Smad signaling. Therefore, RA is a potent therapeutic agent for the treatment of pterygium.

JC-001 is a Chinese medicine that can modulate the immunity in Hepa 1-6 tumor-bearing mice, and we questioned whether JC-001 can serve as efficient adjuvant chemotherapy. We aimed to identify a novel approach for enhancing cis-diamminedichloroplatinum (II) (CDDP)-based chemotherapy by immunomodulation. The anti-tumor activity in vitro was determined based on foci formation and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. A LLC1 tumor xenograft model was used to analyze the activity of tumor rejection in vivo. The tumors were analyzed through hematoxylin and eosin (H&E) staining, immunohistochemistry (IHC) staining and cytokine arrays. JC-001 suppressed foci formation and reduced the viability of Lewis lung carcinoma (LLC1) cells in vitro. JC-001 suppressed LLC1 tumor growth in immunodeficient BALB/c nude mice and in immunocompetent C57BL/6 mice to an even greater extent. Furthermore, JC-001 up-regulated interferon-γ expression in the tumor microenvironment, enhanced the Th1 response in tumor-bearing mice, and increased the chemosensitivity of LLC1 tumors to CDDP chemotherapy. The results of our study suggest that JC-001 is associated with low cytotoxicity and can significantly suppress tumor growth by enhancing the Th1 response. JC-001 is a Chinese medicine with potential clinical applications in CDDP-based chemotherapeutic regimens.