piplartine and Stomach-Neoplasms

To investigate the effects of piperlongumine (PL) and vitamin C (VC) on signal transducer and activator of transcription 3 (STAT3) signalling in gastric cancer cell lines.. Both PL and VC induced apoptosis and inhibited cell proliferation in AGS and KATO III cells. These effects were dependent on reactive oxygen species (ROS). PL effectively suppressed STAT3 activation while VC caused abnormal activation of STAT3. The combination of PL and VC exhibited a stronger apoptotic effect compared with either agent alone. PL reversed the abnormal activation of STAT3 by VC, which could be a key to their synergistic effect.. PL combined with VC exhibited a stronger anticancer effect by regulating the ROS-STAT3 pathway, suggesting that this combination might be a potential adjuvant therapy for gastric cancer.

Topics: Ascorbic Acid; Cell Line, Tumor; Chemotherapy, Adjuvant; Dioxolanes; Humans; Reactive Oxygen Species; STAT3 Transcription Factor; Stomach Neoplasms

Oxaliplatin is one of the most commonly used chemotherapeutic agents in the treatment of various cancers, including gastric cancer. It has, however, a narrow therapeutic index due to its toxicity and the occurrence of drug resistance. Therefore, there is a pressing need to develop novel therapies to potentiate the efficacy and reduce the toxicity of oxaliplatin. Piperlongumine (PL), an alkaloid isolated from Piper longum L., has recently been identified as a potent agent against cancer cells in vitro and in vivo. In the present study, we investigated whether PL can potentiate the antitumor effect of oxaliplatin in gastric cancer cells.. Cellular apoptosis and ROS levels were analyzed by flow cytometry. Thioredoxin reductase 1 (TrxR1) activity in gastric cancer cells or tumor tissues was determined using an endpoint insulin reduction assay. Western blotting was used to analyze the expression levels of the indicated proteins. Nude mice xenograft models were used to test the effects of PL and oxaliplatin combinations on gastric cancer cell growth in vivo.. We found that PL significantly enhanced oxaliplatin-induced growth inhibition in both gastric and colon cancer cells. Moreover, we found that PL potentiated the antitumor effect of oxaliplatin by inhibiting TrxR1 activity. PL combined with oxaliplatin markedly suppressed the activity of TrxR1, resulting in the accumulation of ROS and, thereby, DNA damage induction and p38 and JNK signaling pathway activation. Pretreatment with antioxidant N-acetyl-L-cysteine (NAC) significantly abrogated the combined treatment-induced ROS generation, DNA damage and apoptosis. Importantly, we found that activation of the p38 and JNK signaling pathways prompted by PL and oxaliplatin was also reversed by NAC pretreatment. In vivo, we found that PL combined with oxaliplatin significantly suppressed tumor growth in a gastric cancer xenograft model, and effectively reduced the activity of TrxR1 in tumor tissues. Remarkably, we found that PL attenuated body weight loss evoked by oxaliplatin treatment.. Our data support a synergistic effect of PL and oxaliplatin and suggest that application of its combination may be more effective for the treatment of gastric cancer than oxaliplatin alone.

Topics: Animals; Antineoplastic Agents; Apoptosis; Cell Line, Tumor; Cell Proliferation; Dioxolanes; DNA Damage; Drug Synergism; Female; Humans; MAP Kinase Signaling System; Mice, Inbred BALB C; Mice, Nude; Models, Biological; Oxaliplatin; p38 Mitogen-Activated Protein Kinases; Reactive Oxygen Species; Stomach Neoplasms; Thioredoxin Reductase 1; Xenograft Model Antitumor Assays

The GKN2 is a secretory protein, whose levels decrease in gastric cancer. The present study aimed to investigate the expression, function and mechanism of action of GKN2 in gastric cancer.. Molecular biology assays were performed to elucidate the function and underlying mechanisms of GKN2 in gastric cancer under stress-induced condition in vivo and in vitro. Clinical specimens were used to assess the correlation of GKN2 and prognosis.. We found that overexpression of GKN2 significantly enhanced apoptosis and growth arrest in vitro. GKN2 expression increased in gastric cancer cells exposed to hydrogen peroxide and promoted reactive oxygen species-induced mitochondrial dysfunction and resulted in increased cell apoptosis via inhibition of NF-κB signaling pathway and activation of JNK signaling pathway through the direct interaction of GKN2 with Hsc70. Trefoil factor 1 might contribute to the tumor suppressing effects of GKN2. MiR-216a downregulated GKN2 expression. GKN2 also inhibited xenograft tumor growth and was an independent and significant prognostic factor for patients with gastric cancer treated with oxaliplatin.. Taken together, our data indicate that GKN2 may increase sensitivity of GC cells to the drugs which increase ROS levels in tumors. Inhibition of the interaction between GKN2 and Hsc70 could attenuate the effects induced by GKN2. GKN2 overexpression could be used to determine the subgroup of patients to obtain the more favorable outcome of oxaliplatin treatment and may be used as biomarker of the prognosis of this cancer.

Topics: Adult; Aged; Animals; Antineoplastic Agents; Apoptosis; Carrier Proteins; Caspases; Cell Line, Tumor; Dioxolanes; Disease Models, Animal; Female; Gene Expression; Gene Knockdown Techniques; Genes, Reporter; HSC70 Heat-Shock Proteins; Humans; JNK Mitogen-Activated Protein Kinases; Male; Mice; Middle Aged; NF-kappa B; Oxidation-Reduction; Oxidative Stress; Protein Binding; Signal Transduction; Stomach Neoplasms; Treatment Outcome; Xenograft Model Antitumor Assays

Gastric carcinoma is one of the most common malignancies worldwide and the second most frequent cause of cancer-related death in China. Protein regulator of cytokinesis 1 (PRC1) is involved in cytokinesis and plays key roles in microtubule organization in eukaryotes. This study was aimed to analyse the expression and to investigate the functional role of PRC1 in gastric tumorigenesis. The expression of PRC1 was evaluated by qRT-PCR, Western blot and immunohistochemistry. The biological function of PRC1 was determined by CCK-8 proliferation assays, monolayer colony formation, xenografted nude mice and cell invasion assays by shRNA-mediated knockdown in AGS and HGC27 cells. The regulation of PRC1 expression by piperlongumine was also investigated using dual-luciferase reporter assay and ChIP-qPCR analysis. PRC1 was up-regulated in primary gastric cancers. Overexpression of PRC1 in gastric cancers was associated with poor disease-specific survival and overall survival. PRC1 knockdown in AGS and HGC27 cell lines suppressed proliferation, reduced monolayer colony formation, inhibited cell invasion and migration ability and induced cell-cycle arrest and apoptosis. Inhibition of PRC1 also suppressed tumour growth in vivo. We finally confirmed that PRC1 is a novel downstream target of piperlongumine in gastric cancer. Our findings supported the oncogenic role of PRC1 in gastric carcinogenesis. PRC1 might serve as a prognostic biomarker and potential therapeutic target for gastric carcinoma.

Topics: Biomarkers, Tumor; Carcinogenesis; Carcinoma; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Dioxolanes; Disease-Free Survival; Female; Gene Expression Regulation, Neoplastic; Humans; Male; Stomach Neoplasms; Tumor Suppressor Protein p53

Recently, several studies have shown that piperlongumine (PL) can selectively kill cancer cells by targeting reactive oxygen species (ROS). However, the potential therapeutic effects and detailed mechanism of PL in gastric cancer are still not clear. In the current report, we found that PL significantly suppressed gastric cancer both in vitro and in vivo. PL obviously increased ROS generation in gastric cancer cells. Anti-oxidant glutathione (GSH) and N-acetyl-L-cysteine (NAC) can abrogate PL-induced gastric cancer cell death and proliferation inhibition. GADD45α was induced in PL-treated cancer cells and led to G2/M phase arrest, whereas genetic depletion of GADD45α by small interfering RNAs (siRNAs) could partly reverse PL-induced cell cycle arrest in gastric cancer cells. Interestingly, we also found that PL treatment decreased the expression of telomerase reverse transcriptase (TERT) gene, which plays an essential role in cancer initiation and progression. Our findings thus revealed a potential anti-tumor effect of PL on gastric cancer cells and may have therapeutic implications.

Topics: Acetylcysteine; Animals; Antineoplastic Agents, Phytogenic; Apoptosis; Cell Cycle Proteins; Cell Division; Cell Line, Tumor; Dioxolanes; Endoplasmic Reticulum Stress; G2 Phase Cell Cycle Checkpoints; Glutathione; Humans; Membrane Potential, Mitochondrial; Mice; Mice, Nude; Neoplasm Proteins; Nuclear Proteins; RNA Interference; RNA, Small Interfering; STAT3 Transcription Factor; Stomach Neoplasms; Telomerase; Tumor Stem Cell Assay; X-Linked Inhibitor of Apoptosis Protein; Xenograft Model Antitumor Assays

Piperlongumine (PL), a natural alkaloid isolated from the fruit of long pepper, is known to selectively kill tumor cells while sparing their normal counterparts. However, the cellular target and potent anticancer efficacy of PL in numerous types of human cancer cells have not been fully defined. We report here that PL may interact with the thioredoxin reductase 1 (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme, to induce reactive oxygen species (ROS)-mediated apoptosis in human gastric cancer cells. By inhibiting TrxR1 activity and increasing intracellular ROS levels, PL induces a lethal endoplasmic reticulum stress and mitochondrial dysfunction in human gastric cancer cells. Importantly, knockdown of TrxR1 sensitizes cells to PL treatment, and PL displays synergistic lethality with GSH inhibitors (BSO and Erastin) against gastric cancer cells. In vivo, PL treatment markedly reduces the TrxR1 activity and tumor cell burden. Remarkably, TrxR1 was significantly overexpressed in gastric cancer cell lines and human gastric cancer tissues. Targeting TrxR1 with PL thus discloses a previously unrecognized mechanism underlying the biological activity of PL and provides an in-depth insight into the action of PL in the treatment of gastric cancer.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Dioxolanes; Endoplasmic Reticulum Stress; Female; Humans; Membrane Potential, Mitochondrial; Mice, Inbred BALB C; Mice, Nude; Proto-Oncogene Proteins c-bcl-2; Reactive Oxygen Species; Stomach Neoplasms; Thioredoxin Reductase 1; Tumor Burden; Xenograft Model Antitumor Assays

Piperlongumine (PL), a major active component of long peppers, has been reported to possess anti‑cancer properties; however, its effect on gastric cancer (GC) has remained to be demonstrated. The present study assessed the effects of PL on the MKN45 and AGS GC cell lines and explored the underlying mechanisms. An MTT assay revealed that PL suppressed the proliferation of GC cells, while flow cytometric analysis showed that PL inhibited cell cycle progression. Furthermore, Transwell assays revealed the inhibitory effects of PL on the invasion and migration of GC cells. In addition, PL reduced the phosphorylation of Janus kinase (JAK)1, JAK2 and signal transducer and activator of transcription (STAT)3 in a concentration‑dependent manner, as indicated by western blot analysis, and decreased the expression of STAT3‑dependent tumor‑associated genes in GC cells, as revealed by PCR analysis. In conclusion, the present study was the first, to the best of our knowledge, to reveal the efficacy of PL against GC. The consumption of long peppers is therefore recommended for the prevention and treatment of GC, and PL may be a promising candidate drug for treating GC.

Topics: Cell Line, Tumor; Dioxolanes; Dose-Response Relationship, Drug; Humans; Janus Kinase 1; Janus Kinase 2; Neoplasm Invasiveness; Neoplasm Proteins; Phosphorylation; Signal Transduction; STAT3 Transcription Factor; Stomach Neoplasms

Gastric cancer (GC) is one of the leading causes of cancer mortality in the world. In addressing the need of treatments for relapsed disease, we report the identification of an existing U.S. Food and Drug Administration-approved small-molecule drug to repurpose for GC treatment. Auranofin (AF), clinically used to treat rheumatic arthritis, but it exhibited preclinical efficacy in GC cells. By increasing intracellular reactive oxygen species (ROS) levels, AF induces a lethal endoplasmic reticulum stress response and mitochondrial dysfunction in cultured GC cells. Blockage of ROS production reversed AF-induced ER stress and mitochondrial pathways activation as well as apoptosis. In addition, AF displays synergistic lethality with an ROS-generating agent piperlongumine, which is a natural product isolated from the long pepper Piper longum L. Taken together, this work provides a novel anticancer candidate for the treatment of gastric cancer. More importantly, it reveals that increased ROS generation might be an effective strategy in treating human gastric cancer.

Topics: Animals; Antineoplastic Combined Chemotherapy Protocols; Antirheumatic Agents; Apoptosis; Auranofin; Dioxolanes; Drug Synergism; Endoplasmic Reticulum Stress; Female; Humans; Mice; Mice, Inbred BALB C; Mice, Nude; Mitochondria; Reactive Oxygen Species; Stomach Neoplasms; Xenograft Model Antitumor Assays