Periplocin inhibits the growth of pancreatic cancer by inducing apoptosis via AMPK-mTOR signaling

Periplcymarin targets glycolysis and mitochondrial oxidative phosphorylation of esophageal squamous cell carcinoma: Implication in anti-cancer therapy

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is the predominant histological subtype of esophageal cancer (EC) in China, and demonstrates varying levels of resistance to multiple chemotherapeutic agents. Our previous studies have proved that periplocin (CPP), derived from the extract of cortex periplocae, exhibiting the capacity to hinder proliferation and induce apoptosis in ESCC cells. Several studies have identified additional anti-cancer constituents in the extract of cortex periplocae, named periplcymarin (PPM), sharing similar compound structure with CPP. Nevertheless, the inhibitory effects of PPM on ESCC and their underlying mechanisms remain to be further elucidated.

PURPOSE

The aim of this study was to investigate function of PPM inhibiting the growth of ESCC in vivo and in vitro and to explore its underlying mechanism, providing the potential anti-tumor drug for ESCC.

METHODS

Initially, a comparative analysis was conducted on the inhibitory activity of three naturally compounds obtained from the extract of cortex periplocae on ESCC cells. Among these compounds, PPM was chosen for subsequent investigation owing to its comparatively structure and anti-tumor activity simultaneously. Subsequently, a series of biological functional experiments were carried out to assess the impact of PPM on the proliferation, apoptosis and cell cycle arrest of ESCC cells in vitro. In order to elucidate the molecular mechanism of PPM, various methodologies were employed, including bioinformatics analyses and mechanistic experiments such as high-performance liquid chromatography combined with mass spectrometry (HPLC-MS), cell glycolysis pressure and mitochondrial pressure test. Additionally, the anti-tumor effects of PPM on ESCC cells and potential toxic side effects were evaluated in vivo using the nude mice xenograft assay.

RESULTS

Our study revealed that PPM possesses the ability to impede the proliferation of ESCC cells, induce apoptosis, and arrest the cell cycle of ESCC cells in the G2/M phase in vitro. Mechanistically, PPM exerted its effects by modulating glycolysis and mitochondrial oxidative phosphorylation (OXPHOS), as confirmed by glycolysis pressure and mitochondrial pressure tests. Moreover, rescue assays demonstrated that PPM inhibits glycolysis and OXPHOS in ESCC cells through the PI3K/AKT and MAPK/ERK signaling pathways. Additionally, we substantiated that PPM effectively suppresses the growth of ESCC cells in vivo, with only modest potential toxic side effects.

CONCLUSION

Our study provides novel evidence that PPM has the potential to simultaneously target glycolysis and mitochondrial OXPHOS in ESCC cells. This finding highlights the need for further investigation into PPM as a promising therapeutic agent that targets the tumor glucose metabolism pathway in ESCC.

Fundamental insights and molecular interactions in pancreatic cancer: Pathways to therapeutic approaches

The gastrointestinal tract can be affected by a number of diseases that pancreatic cancer (PC) is a malignant manifestation of them. The prognosis of PC patients is unfavorable and because of their diagnosis at advanced stage, the treatment of this tumor is problematic. Owing to low survival rate, there is much interest towards understanding the molecular profile of PC in an attempt in developing more effective therapeutics. The conventional therapeutics for PC include surgery, chemotherapy and radiotherapy as well as emerging immunotherapy. However, PC is still incurable and more effort should be performed. The molecular landscape of PC is an underlying factor involved in increase in progression of tumor cells. In the presence review, the newest advances in understanding the molecular and biological events in PC are discussed. The dysregulation of molecular pathways including AMPK, MAPK, STAT3, Wnt/β-catenin and non-coding RNA transcripts has been suggested as a factor in development of tumorigenesis in PC. Moreover, cell death mechanisms such as apoptosis, autophagy, ferroptosis and necroptosis demonstrate abnormal levels. The EMT and glycolysis in PC cells enhance to ensure their metastasis and proliferation. Furthermore, such abnormal changes have been used to develop corresponding pharmacological and nanotechnological therapeutics for PC.

DT-13 inhibits the proliferation of pancreatic cancer by inducing apoptosis via AMPK-mTOR signaling

BACKGROUND/OBJECTIVE

DT-13, the principal active component of Mysidium shortscapes from the Liliaceae family, has garnered substantial interest in cancer therapy owing to its potential anticancer properties. This study investigated the effects of DT-13 on the proliferation and apoptosis of human pancreatic cancer cell lines and aimed to elucidate the underlying mechanisms.

METHODS

PANC1 and CFPAC1 cells were exposed to DT-13 and their proliferation was assessed using RTCA and clone formation assays. Apoptotic protein expression was analyzed by western blotting, and apoptotic cells were identified by flow cytometry. RNA was extracted from DT-13 treated and untreated PANC1 cells for RNA sequencing. Differentially expressed genes were identified and subjected to GO bioprocess, KEGG pathway analysis, and western blotting. Finally, to evaluate tumor growth, CFPAC1 cells were subcutaneously injected into BALB/c nude mice.

RESULTS

DT-13 inhibited proliferation and induced apoptosis of PANC1 and CFPAC1 cells by activating the AMPK/mTOR pathway and suppressing p70 S6K. Moreover, DT-13 hindered the growth of CFPAC1 xenograft tumors in nude mice.

CONCLUSIONS

DT-13 effectively inhibited the growth of human pancreatic cancer cells.

Study of the PI3K/Akt/mTOR signaling pathway in vitro and molecular docking analysis of periplocin inhibits cell cycle progression and induces apoptosis in MDA-MB-231

Breast cancer mainly affects women and is the second leading cause of cancer-related deaths worldwide. Breast cancer affects women aged 15-59. The current study explored periplocin's anticancer activities against breast cancer MDA-MB-231 cells by down-regulating the PI3K/Akt/mTOR pathway. The MTT assay assessed control-treated and periplocin (2.5-50 μM) treated MDA-MB-231 cell viability. ROS accumulation and apoptosis levels in periplocin-treated cells were examined using DAPI, dual staining, and Annexin V-FITC/PI assays. Caspase enzymes were studied using assay kits. Flow cytometry was used to measure cell cycle distributions. Periplocin-treated cells were analyzed using RT-PCR assays and insilico analyses for the expression of PI3K/Akt/mTOR molecules. The periplocin treatment remarkably reduced the viability of the MDA-MB-231 cells, with an IC50 concentration of 7.5 μM. The fluorescent staining assays revealed a substantial increase in ROS levels and apoptotic events in the periplocin-treated cells. The flow cytometry analysis revealed that periplocin triggered apoptosis and arrested the cell cycle in G0/G1 phases. Periplocin increased the caspase-3, -8, and -9 enzyme activities. In MDA-MB-231 cells, Periplocin decreased PI3K/Akt/mTOR activity, and in silico analysis, Periplocin was inhibited by CDK8-Cyclin C interactions. Periplocin has anticancer properties against breast cancer and may be an effective therapeutic agent for treating breast cancer.

Periplocin suppresses the growth of colorectal cancer cells by triggering LGALS3 (galectin 3)-mediated lysophagy

Colorectal cancer (CRC) is one of the most common malignancies worldwide and remains a major clinical challenge. Periplocin, a major bioactive component of the traditional Chinese herb Cortex periplocae, has recently been reported to be a potential anticancer drug. However, the mechanism of action is poorly understood. Here, we show that periplocin exhibits promising anticancer activity against CRC both in vitro and in vivo. Mechanistically, periplocin promotes lysosomal damage and induces apoptosis in CRC cells. Notably, periplocin upregulates LGALS3 (galectin 3) by binding and preventing LGALS3 from Lys210 ubiquitination-mediated proteasomal degradation, leading to the induction of excessive lysophagy and resultant exacerbation of lysosomal damage. Inhibition of LGALS3-mediated lysophagy attenuates periplocin-induced lysosomal damage and growth inhibition in CRC cells, suggesting a critical role of lysophagy in the anticancer effects of periplocin. Taken together, our results reveal a novel link between periplocin and the lysophagy machinery, and indicate periplocin as a potential therapeutic option for the treatment of CRC.Abbreviations: 3-MA: 3-methyladenine; ACACA/ACC1: acetyl-CoA carboxylase alpha; AMPK: adenosine monophosphate-activated protein kinase; AO: Acridine orange; ATG5: autophagy related 5; ATG7: autophagy related 7; CALM: calmodulin; CHX: cycloheximide; CRC: colorectal cancer; CQ: chloroquine; CTSB: cathepsin B; CTSD: cathepsin D; ESCRT: endosomal sorting complex required for transport; LAMP1: lysosomal associated membrane protein 1; LMP: lysosomal membrane permeabilization; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; MCOLN1/TRPML1: mucolipin TRP cation channel 1; MKI67/Ki-67: marker of proliferation Ki-67; MTOR: mechanistic target of rapamycin kinase; P2RX4/P2X4: purinergic receptor P2X 4; PARP1/PARP: poly(ADP-ribose) polymerase 1; PRKAA/AMPKα: protein kinase AMP-activated catalytic subunit alpha; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TRIM16: tripartite motif containing 16.

Periplocin inhibits hepatocellular carcinoma progression and reduces the recruitment of MDSCs through AKT/NF-κB pathway

AIMS

We aimed to evaluate the effect of periplocin on inhibiting hepatocellular carcinoma (HCC) and further determine its mechanisms.

MAIN METHODS

Cytotoxic activity of periplocin against HCC cells was tested by CCK-8 and colony formation assays. The antitumor effects of periplocin were evaluated in human HCC SK-HEP-1 xenograft and murine HCC Hepa 1-6 allograft mouse models. Flow cytometry was used to measure cell cycle distribution, apopotosis, and the number of myeloid-derived suppressor cells (MDSCs). Hoechst 33258 dye was applied to observe the nuclear morphology. Network pharmacology was performed to predict possible signaling pathways. Drug affinity responsive target stability assay (DARTS) was used to evaluate AKT binding of periplocin. Western blotting, immunohistochemistry, and immunofluorescence were used to examine the protein expression levels.

KEY FINDING

Periplocin inhibited cell viability with IC₅₀ values from 50 nM to 300 nM in human HCC cells. Periplocin disrupted cell cycle distribution and promoted cell apoptosis. Moreover, AKT was predicted as the target of periplocin by network pharmacology, which was confirmed by that AKT/NF-κB signaling was inhibited in periplocin-treated HCC cells. Periplocin also inhibited the expression of CXCL1 and CXCL3, leading to decreased accumulation of MDSCs in HCC tumors.

SIGNIFICANCE

These findings reveal the function of periplocin in inhibiting HCC progression by G₂/M arrest, apoptosis and suppression of MDSCs accumulation through blockade of the AKT/NF-κB pathway. Our study further suggests that periplocin has the potential to be developed as an effective therapeutic agent for HCC.

Periplocin targets low density lipoprotein receptor-related protein 4 to attenuate osteoclastogenesis and protect against osteoporosis

Osteoporosis is a common inflammaging-related condition, where long-term accumulation of pro-inflammatory cytokines causes massive bone loss. Periplocin, a cardiotonic steroid isolated from Periploca forrestii, has been proved to reduce inflammation in several inflammatory diseases, such as rheumatoid arthritis. However, its effect and mechanism of inflammation in osteoporosis, in which pro-inflammatory factors accelerate bone loss, has not been well demonstrated. In this study, periplocin attenuated receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclast differentiation of bone marrow-derived macrophages (BMMs) and RAW264.7 cells in vitro. It reduced osteoclast numbers and bone resorption in a concentration- and time-dependent manner. Further, periplocin treatment resulted in reduced bone loss on mice with ovariectomy-induced osteoporosis in vivo. By transcriptome sequencing, periplocin was indicated to function through inhibition of the mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB) signaling pathways and attenuating interactions between NF-κB and nuclear factor of activated T-cells 1 (NFATc1). It was further detected to bind low density lipoprotein receptor-related protein 4 (LRP4) in osteoclasts to exert anti-inflammatory and anti-osteoclastic effects. Overall, the findings have highlighted a better understanding for the anti-inflammatory and anti-osteoclastic role of periplocin in osteoporosis and its mechanism, bringing new possibilities for osteoporosis treatment.

Periplocin Overcomes Bortezomib Resistance by Suppressing the Growth and Down-Regulation of Cell Adhesion Molecules in Multiple Myeloma

Multiple myeloma (MM) is an incurable hematological malignant disorder of bone marrow. Patients with MM receive multiple lines of chemotherapeutic treatments which often develop bortezomib (BTZ) resistance and relapse. Therefore, it is crucial to identify an anti-MM agent to overcome the BTZ resistance of MM. In this study, we screened a library of 2370 compounds against MM wild-type (ARP1) and BTZ-resistant type (ARP1-BR) cell lines and found that periplocin (PP) was the most significant anti-MM natural compound. We further investigated the anti-MM effect of PP by using annexin V assay, clonogenic assays, aldefluor assay, and transwell assay. Furthermore, RNA sequencing (RNA-seq) was performed to predict the molecular effects of PP in MM followed by verification through qRT-PCR and Western blot analysis. Moreover, ARP1 and ARP1-BR xenograft mice models of MM were established to confirm the anti-MM effects of PP invivo. The results showed that PP significantly induced apoptosis, inhibited proliferation, suppressed stemness, and reduced the cell migration of MM. The expression of cell adhesion molecules (CAMs) was suppressed upon PP treatment in vitro and in vivo. Overall, our data recommend PP as an anti-MM natural compound with the potential to overcome BTZ resistance and downregulate CAMs in MM.

Dual targets of lethal apoptosis and protective autophagy in liver cancer with periplocymarin elicit a limited therapeutic effect

Cardiac glycosides (CGs) are candidate anticancer agents that function by increasing [Ca²⁺]i to induce apoptotic cell death in several types of cancer cells. However, new findings have shown that the anti‑cancer effects of CGs involve complex cell‑signal transduction mechanisms. Hence, exploring the potential mechanisms of action of CGs may provide insight into their anti‑cancer effects and thus aid in the selection of the appropriate CG. Periplocymarin (PPM), which is a cardiac glycoside, is an active ingredient extracted from Cortex periplocae. The role of PPM was evaluated in HepG2 cells and xenografted nude mice. Cell proliferation, real‑time ATP rate assays, western blotting, cell apoptosis assays, short interfering RNA transfection, the patch clamp technique, electron microscopy, JC‑1 staining, immunofluorescence staining and autophagic flux assays were performed to evaluate the function and regulatory mechanisms of PPM in vitro. The in vivo activity of the PPM was assessed using a mouse xenograft model. The present study demonstrated that PPM synchronously activated lethal apoptosis and protective autophagy in liver cancer, and the initiation of autophagy counteracted the inherent pro‑apoptotic capacity and impaired the anti‑cancer effects. Specifically, PPM exerted a pro‑-apoptotic effect in HepG2 cells and activated macroautophagy by initiation of the AMPK/ULK1 and mTOR signaling pathways. Activation of macroautophagy counteracted the pro‑apoptotic effects of PPM, but when it was combined with an autophagy inhibitor, the anti‑cancer effects of PPM in mice bearing HepG2 xenografts were observed. Collectively, these results indicated that a self‑limiting effect impaired the pro‑apoptotic effects of PPM in liver cancer, but when combined with an autophagy inhibitor, it may serve as a novel therapeutic option for the management of liver cancer.

Periplocin Alleviates Cardiac Remodeling in DOCA-Salt-Induced Heart Failure Rats

Heart failure with preserved ejection fraction (HFpEF) is a common public health problem associated with increased morbidity and long-term mortality. However, effective treatment for HFpEF was not discovered yet. In the present study, we aimed to decipher the effects of Periplocin on DOCA-induced heart failure rats and explore the possible underlying mechanisms. We demonstrated that Periplocin could significantly attenuate cardiac structural remodeling and improve cardiac diastolic function. Of note, Periplocin significantly inhibited the recruitment of inflammatory and immune cells and decreased the expression of serum inflammatory cytokines. Meanwhile, Periplocin had the effect of cardiac glycosides to improve cardiomyocyte contractility and calcium transient amplitude. These findings indicate that Periplocin might be a potential medicine to treat HFpEF in patients.

Periplocin exerts antitumor activity by regulating Nrf2-mediated signaling pathway in gemcitabine-resistant pancreatic cancer cells

Although gemcitabine-based chemotherapy is common and effective for pancreatic cancer (PC), acquired drug resistance is one of the major reasons for treatment failure. Therefore, a novel therapeutic approach for gemcitabine-resistant PC is required. Nuclear factor erythroid 2-related factor 2 (Nrf2) is an oxidative stress-responsive transcription factor regulating antioxidant responses and plays a crucial role in chemoresistance. In the present study, the antitumor activity of periplocin, a natural cardiac glycoside, was evaluated in an established gemcitabine-resistant PC cell line (PANC-GR). Nrf2 was overexpressed in gemcitabine-resistant cells, and Nrf2 knockdown recovered gemcitabine sensitivity in PANC-GR cells. The antiproliferative activity of periplocin was highly associated with Nrf2 downregulation and Nrf2-mediated signaling pathways in PANC-GR cells. Periplocin also increased reactive oxygen species production inducing G₀/G₁ cell cycle arrest and apoptosis in PANC-GR cells. Periplocin and gemcitabine combined significantly inhibited tumor growth in a PANC-GR cells-implanted xenograft mouse model via Nrf2 downregulation. Overall, these findings suggest that periplocin might be a novel therapeutic agent against gemcitabine resistance, as it could recover sensitivity to gemcitabine by regulating Nrf2-mediated signaling pathways in gemcitabine-resistant PC cells.

Aspiletrein A Induces Apoptosis Cell Death via Increasing Reactive Oxygen Species Generation and AMPK Activation in Non-Small-Cell Lung Cancer Cells

Lung cancer remains a leading cause of death in cancer patients, and deregulation of apoptosis is a serious concern in clinical practice, even though therapeutic intervention has been greatly improved. Plants are a versatile source of biologically active compounds for anticancer drug discovery, and aspiletrein A (AA) is a steroidal saponin isolated from Aspidistra letreae that has a potent cytotoxic effect on various cancer cell lines. In this study, we investigated and determined the underlying molecular mechanism by which AA induces apoptosis. AA strongly induced apoptosis in NSCLC cells by mediating ROS generation and thereby activating AMP-activated protein kinase (AMPK) signaling. Consequently, downstream signaling and levels of phosphorylated mTOR and Bcl-2 were significantly decreased. Pretreatment with either an antioxidant, N-acetylcysteine, or an AMPK inhibitor, compound C, could reverse the apoptosis-inducing effect and counteract the effect of AA on the AMPK signaling pathway. Decreased levels of Bcl-2 were due to AA-mediating Bcl-2 degradation via a ROS/AMPK/mTOR axis-dependent proteasomal mechanism. Consistently, the apoptotic-inducing effect of AA was also observed in patient-derived malignant lung cancer cells, and it suppressed an in vitro 3D-tumorigenesis. This study identified the underlying mechanism of AA on lung cancer apoptosis, thereby facilitating potential research and development of this compound for further clinical implications.

Autophagy: A Key Player in Pancreatic Cancer Progression and a Potential Drug Target

Simple Summary

With the mortality rate of pancreatic cancer predicted to rise over the coming years, it is essential that effective treatment strategies are developed as soon as possible. Pancreatic cancer has always proven very difficult to treat due to its fast growing and aggressive nature. Chemotherapeutic treatment has struggled to increase the survival rate of pancreatic cancer patients due to effective chemo-resistant properties that derive from the supporting tumor microenvironment and autophagy, a vital survival pathway. This review will explore how the autophagy pathway and tumor microenvironment help to sustain tumor survival under stress and expand into a metastatic state. Due to the comprehensive understanding of the autophagy pathway, we will highlight the potential chinks in the pancreatic tumor’s armor and identify potential targets to overcome chemo-resistance in pancreatic cancer. We will also present novel autophagy inhibitors that could reduce tumor survival and how they could be most effectively conceived.

Abstract

Pancreatic cancer is known to have the lowest survival outcomes among all major cancers, and unfortunately, this has only been marginally improved over last four decades. The innate characteristics of pancreatic cancer include an aggressive and fast-growing nature from powerful driver mutations, a highly defensive tumor microenvironment and the upregulation of advantageous survival pathways such as autophagy. Autophagy involves targeted degradation of proteins and organelles to provide a secondary source of cellular supplies to maintain cell growth. Elevated autophagic activity in pancreatic cancer is recognized as a major survival pathway as it provides a plethora of support for tumors by supplying vital resources, maintaining tumour survival under the stressful microenvironment and promoting other pathways involved in tumour progression and metastasis. The combination of these features is unique to pancreatic cancer and present significant resistance to chemotherapeutic strategies, thus, indicating a need for further investigation into therapies targeting this crucial pathway. This review will outline the autophagy pathway and its regulation, in addition to the genetic landscape and tumor microenvironment that contribute to pancreatic cancer severity. Moreover, this review will also discuss the mechanisms of novel therapeutic strategies that inhibit autophagy and how they could be used to suppress tumor progression.

Periplocin Induces Apoptosis of Pancreatic Cancer Cells through Autophagy via the AMPK/mTOR Pathway

Periplocin, a natural compound, has been shown to induce apoptosis in a variety of cancer cells. However, no research has been conducted to demonstrate that Periplocin has a regulatory effect on autophagy. This study is aimed to determine the effect of Periplocin treatment on autophagy in human pancreatic cancer cells, as well as the underlying mechanisms. Pancreatic cancer cells were treated with different concentrations of Periplocin, and real-time cell analysis (RTCA), colony formation assay, and Ki67 immunofluorescence detection were used to determine cell proliferation. Autophagy protein was detected by immunofluorescence and western blotting. Western blotting was also used to detect the caspase family of apoptotic proteins. Flow cytometry and TUNEL staining were used to detect cell apoptosis. Following treatment with Periplocin, the expression of autophagy genes was detected using RNA-seq. In vivo examination of the effect of Periplocin on autophagy in pancreatic was performed using a xenograft model. Periplocin inhibits the proliferation of CFPAC1 and PANC1 cells and induces autophagy by regulating the AMPK/mTOR pathway. Using the AMPK inhibitor Compound C(CC), both the Periplocin-induced inhibition of cell proliferation and autophagy activation was reduced, which further verified this conclusion. Periplocin inhibits CFPAC1 xenograft tumor growth in nude mice and increases tumor cell autophagy. Collectively, these results have shown that Periplocin promotes autophagy in human pancreatic cancer cells by regulating the AMPK/mTOR pathway.

Periplocin ameliorates mouse age-related meibomian gland dysfunction through up-regulation of Na/K-ATPase via SRC pathway

Age-related meibomian gland dysfunction (MGD) is the main cause of evaporative dry eye disease in an aging population. Decreased meibocyte cell renewal and lipid synthesis are associated with age-related MGD. Here, we found an obvious decline of Ki67, ΔNp63, and Na+/K+ ATPase expression in aged meibomian glands. Potential Na+/K+ ATPase agonist periplocin, a naturally occurring compound extracted from the traditional herbal medicine cortex periplocae, could promote the proliferation and stem cell activity of meibocyte cells in vitro. Moreover, we observed that periplocin treatment effectively increased the expression of Na+ /K+ ATPase, accompanied with the enhanced expression of Ki67 and ΔNp63 in aged meibomian glands, indicating that periplocin may accelerate meibocyte cell renewal in aged mice. LipidTox staining showed increased lipid accumulation after periplocin treatment in cultured meibomian gland cells and aged meibomian glands. Furthermore, we demonstrated that the SRC pathway was inhibited in aged meibomian glands; however, it was activated by periplocin. Accordingly, the inhibition of the SRC signaling pathway by saracatinib blocked periplocin-induced proliferation and lipid accumulation in meibomian gland cells. In sum, we suggest periplocin-ameliorated meibocyte cell renewal and lipid synthesis in aged meibomian glands via the SRC pathway, which could be a promising candidate for age-related MGD.

Simultaneous determination of periplocin, periplocymarin, periplogenin, periplocoside M and periplocoside N of Cortex Periplocae in rat plasma and its application to a pharmacokinetic study

A sensitive and specific ultra-performance liquid chromatographic-tandem mass spectrometric method was developed and validated to simultaneously determine periplocin, periplocymarin (PM), periplogenin (PG), periplocoside M (PSM) and periplocoside N (PSN) in rat plasma. Acetonitrile was employed to precipitate plasma with appropriate sensitivity and acceptable matrix effects. Chromatographic separation was performed using a Waters HSS T3 column with a gradient elution using water and acetonitrile both containing 0.1% formic acid and 0.1 mm ammonium formate within 8 min. Detection was performed in positive ionization mode using multiple reaction monitoring. The method was fully validated in terms of selectivity, linearity, accuracy, precision, recovery, matrix effects and stability. Using this method, the concentrations of periplocin, PM, PG, PSM and PSN were established after oral administration of Cortex Periplocae extract to rats, and the pharmacokinetic characteristics of periplocin, PM, PG, PSM and PSN were assessed. Generally, PM, PG, PSM and PSN were eliminated slowly and their half-lives were all >8 h. In addition, the systemic exposure of PSM showed significant differences between genders with more than 10 times higher area under the concentration-time curve in female rats than in male rats. The findings of this study provide useful information for further research on Cortex Periplocae.

Synthesis, Anti-Proliferative Evaluation and Mechanism of 4-Trifluoro Methoxy Proguanil Derivatives with Various Carbon Chain Length

Among the known biguanide drugs, proguanil has the best antiproliferative activity. In contrast, newly synthesized biguanide derivatives containing fluorine atoms have excellent biological activity, among which trifluoromethoxy compounds show the strongest ability. Preliminary work in our laboratory exhibited that n-heptyl containing proguanil derivatives on one alkyl chain side have better biological activity than those with a shorter carbon chain. However, the relationship between the length of the carbon chain and the activity of the compounds is unknown. In this study, we synthesized 10 new trifluoromethoxy-containing proguanil derivatives with various carbon chain lengths. The phenyl side is fixed as the trifluoromethoxy group with change of carbon chain length in alkyl chain side. It was found that the anti-cancer abilities of 5C-8C with n-pentyl to n-octyl groups was significantly better than that of proguanil in the five human cancer cell lines. The colony formation assay demonstrated that 6C-8C at 0.5 to 1.0 μM significantly inhibited the colony formation of human cancer cell lines, much stronger than that of proguanil. Pharmacologically, 8C activates AMPK, leading to inactivation of the mTOR/p70S6K/4EBP1 pathway. Thus, these novel compounds have a great potential for developing new anti-cancer candidates.

Novel therapeutic strategies and perspectives for pancreatic cancer: Autophagy and apoptosis are key mechanisms to fight pancreatic cancer

Pancreatic cancer (PC) is the most lethal malignancy of the gastrointestinal tract. The poor prognosis of patients with PC is primarily due to lack of effective treatments against its progressive and metastatic behavior. Hence, figuring out the mechanisms underlying PC development and putting up with effective targeted therapies are of great significance to improve the prognosis of patients with PC. Apoptosis and autophagy serve to maintain tissue homoeostasis. Escaping from apoptosis or autophagy is one of the features of malignancy. PC is seriously resistant to autophagy and apoptosis, which explains its invasiveness and resistance to conventional treatment. Recently, several biological activities and pharmacological functions found in natural product extracts have been reported to inhibit PC progression. The current review focuses on understanding natural product extracts and their derivatives as one kind of novel treatments through affecting the apoptosis or autophagy in PC.