TMT-Based Quantitative Proteomic Analysis Identified Proteins and Signaling Pathways Involved in the Response to Xanthatin Treatment in Human HT-29 Colon Cancer Cells

Tandem mass tag-based quantitative proteomics analyses of the spermatogenesis-ameliorating effect of Youjing granule on rats

RATIONALE

Male infertility is a common reproductive system disease manifested as aberrant spermatogenesis and identified as "kidney deficiency and dampness" in Chinese traditional medicine. Youjing granule (YG) is a Chinese material medica based on tonifying kidneys and removing dampness. It has proven to be able to regulate semen quality in clinical application, but the underlying mechanism has not been clarified.

METHODS

Using serum containing YG to treat primarily cultured spermatogonial stem cells (SSCs), the apoptotic rate and mitosis phase ratio of SSCs were measured. The liquid chromatography-tandem mass spectrometry with tandem mass tags method was applied for analyzing the serum of rats treated with YG/distilled water, and proteomic analyses were performed to clarify the mechanisms of YG.

RESULTS

Totally, 111 proteins in YG-treated serum samples were differentially expressed compared with control groups, and 43 of them were identified as potential target proteins, which were further annotated based on their enrichment in Gene Ontology terms and Kyoto Encyclopedia of Genes and Genomes pathways. Proteomic analyses showed that the mechanisms of YG may involve regulation of glycolysis, gluconeogenesis and nucleotide-binding and oligomerization domain-like receptor signaling pathway. In addition, RhoA and Lamp2 were found to be possible responders of YG through reviewing the literature.

CONCLUSIONS

The results demonstrate that our serum proteomics platform is clinically useful in understanding the mechanisms of YG.

Xanthatin suppresses pancreatic cancer cell growth via the ROS/RBL1 signaling pathway: In vitro and in vivo insights

BACKGROUND

As a malignant digestive system tumor, pancreatic cancer has a high mortality rate. Xanthatin is a sesquiterpene lactone monomer compound purified from the traditional Chinese herb Xanthium strumarium L. It has been reported that Xanthatin exhibits inhibitory effects on various cancer cells in retinoblastoma, glioma, hepatoma, colon cancer, lung cancer, as well as breast cancer. However, in pancreatic cancer cells, only one report exists on the suppression of Prostaglandin E2 synthesis and the induction of caspase 3/7 activation in Xanthatin-treated MIA PaCa-2 cells, while systematic in vitro and in vivo investigations and related mechanisms have yet to be explored.

PURPOSE

This research aims to explore the in vitro and in vivo effects of Xanthatin on pancreatic cancer and its molecular mechanisms.

METHODS

The anticancer effects and mechanisms of Xanthatin on pancreatic cancer cells were assessed through employing cell counting kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) assay, carboxyfluorescein diacetate succinimidyl ester (CFDA SE) cell proliferation assay, colony formation assay, wound healing assay, transwell assay, Annexin V-FITC/propidium iodide (PI) dual staining, Hoechst nuclear staining, Western blot analysis, phosphoproteomics, and reactive oxygen species (ROS) measurement. The in vivo anticancer effects of Xanthatin on pancreatic cancer cells were studied using a nude mouse model.

RESULTS

The present study showed that Xanthatin can prevent the proliferation and metastasis of pancreatic cancer cells and trigger the exposure of phosphatidylserine (PS), chromatin condensation, and caspase activation, thereby inducing apoptosis. Phosphoproteomic analysis indicated that Xanthatin inhibits the phosphorylation of the proliferation-associated protein RBL1, and oxidative stress can lead to RBL1 dephosphorylation. Further investigation revealed that Xanthatin significantly upregulates ROS levels in pancreatic cancer cells, and the antioxidant N-acetylcysteine (NAC) can reverse Xanthatin-induced cell proliferation inhibition and apoptosis. In addition, Xanthatin can suppress pancreatic cancer cell growth in a xenograft nude mouse model with low toxicity to the mice.

CONCLUSION

Xanthatin may inhibit the proliferation of pancreatic cancer cells and trigger apoptosis through the ROS/RBL1 signaling pathway.

Neurotoxicity of sanguinarine via inhibiting mitophagy and activating apoptosis in zebrafish and PC12 cells

Sanguinarine, a plant-derived phytoalexin, displays various biological activities, such as insecticidal, antimicrobial, anti-inflammatory, anti-angiogenesis and antitumor effects. But its potential neurotoxicity and the underlying mechanisms has rarely been investigated. Therefore, we aimed to assess the neurotoxicity of sanguinarine using zebrafish model and PC12 cells in this study. The results showed that sanguinarine induced the reduction of the length of dopamine neurons and inhibited the blood vessel in the head area of the zebrafish. Further studies demonstrated that the behavioral phenotype of the larval zebrafish was changed by sanguinarine. In addition, there were more apoptotic cells in the larval zebrafish head area. The mRNA expression levels of β-syn, th, pink1 and parkin, closely related to the nervous function, were changed after sanguinarine treatment. The in vitro studies show that notably increases of ROS and apoptosis levels in PC12 cells were observed after sanguinarine treatment. Moreover, the protein expression of Caspase3, Parp, Bax, Bcl2, α-Syn, Th, PINK1 and Parkin were also altered by sanguinarine. Our data indicated that the inhibition of mitophagy, ROS elevation and apoptosis were involved in the neurotoxicity of sanguinarine. These findings will be useful to understand the toxicity induced by sanguinarine.

Sestrin2 in cancer: a foe or a friend?

Sestrin2 is a conserved antioxidant, metabolism regulator, and downstream of P53. Sestrin2 can suppress oxidative stress and inflammation, thereby preventing the development and progression of cancer. However, Sestrin2 attenuates severe oxidative stress by activating nuclear factor erythroid 2-related factor 2 (Nrf2), thereby enhancing cancer cells survival and chemoresistance. Sestrin2 inhibits endoplasmic reticulum stress and activates autophagy and apoptosis in cancer cells. Attenuation of endoplasmic reticulum stress and augmentation of autophagy hinders cancer development but can either expedite or impede cancer progression under specific conditions. Furthermore, Sestrin2 can vigorously inhibit oncogenic signaling pathways through downregulation of mammalian target of rapamycin complex 1 (mTORC1) and hypoxia-inducible factor 1-alpha (HIF-1α). Conversely, Sestrin2 decreases the cytotoxic activity of T cells and natural killer cells which helps tumor cells immune evasion. Sestrin2 can enhance tumor cells viability in stress conditions such as glucose or glutamine deficiency. Cancer cells can also upregulate Sestrin2 during chemotherapy or radiotherapy to attenuate severe oxidative stress and ER stress, augment autophagy and resist the treatment. Recent studies unveiled that Sestrin2 is involved in the development and progression of several types of human cancer. The effect of Sestrin2 may differ depending on the type of tumor, for instance, several studies revealed that Sestrin2 protects against colorectal cancer, whereas results are controversial regarding lung cancer. Furthermore, Sestrin2 expression correlates with metastasis and survival in several types of human cancer such as colorectal cancer, lung cancer, and hepatocellular carcinoma. Targeted therapy for Sestrin2 or regulation of its expression by new techniques such as non-coding RNAs delivery and vector systems may improve cancer chemotherapy and overcome chemoresistance, metastasis and immune evasion that should be investigated by future trials.