Rottlerin suppresses growth of human pancreatic tumors in nude mice, and pancreatic cancer cells isolated from Kras(G12D) mice

Rottlerin and genistein inhibit neuroblastoma cell proliferation and invasion through EF2K suppression and related protein pathways

Neuroblastoma is one of the most common solid tumors in children younger than 1 year of age, with poor prognosis and survival rates. Therefore, novel molecular targets and therapeutic strategies are needed to prolong patient survival. For this purpose, we investigated the effects of rottlerin and genistein separately and in combination on neuroblastoma cells (SH-SY5Y, Kelly). First, the effects of rottlerin and genistein were investigated on cell proliferation. Different rottlerin (1-50 µM) and genistein (5-150 µM) doses were used as experimental groups compared to the control (DMSO/vehicle). The IC50 dose was found to be 5 µM for rottlerin and 30 µM for genistein (P < 0.0001). Other analyses, such as colony formation assays, annexin V/propidium iodide staining, matrigel invasion assays, and Western blot analysis, were performed with these doses and their combinations. To assess statistical significance, statistical analysis was conducted using the one-way ANOVA with the post hoc Tukey test. Our results showed that IC50 doses of rottlerin and genistein induced a significant reduction in cell proliferation, colony formation, and invasion in neuroblastoma cells (P < 0.0001). The combination of these doses increased the levels of inhibition of cell proliferation and invasion while decreasing the level of apoptosis (P 0.0001). Furthermore, these agents caused G1-cell cycle arrest in these cells. Our western blot data showed that rottlerin and genistein treatments markedly inhibit elongation factor 2 kinase (EF2K) and other pro-tumorigenic, metastatic proteins in neuroblastoma cells. These agents probably showed their anti-proliferative, anti-metastatic, and pro-apoptotic effects through EF2K downregulation. Our results suggested that rottlerin and genistein have inhibitory effects on cancer cell proliferation, invasion, and cell cycle and induce apoptosis in both cell lines. Combined treatment with rottlerin and genistein may be a viable approach and beneficial to neuroblastoma patients as the combined effect significantly suppresses the above-mentioned pathways.

Rottlerin promotes anti-metastatic events by ameliorating pharmacological parameters of paclitaxel: An in-vivo investigation in the orthotopic mouse model of breast cancer

Despite substantial breakthroughs in cancer research, there is hardly any specific therapy available to date that can alleviate triple-negative breast cancer (TNBC). Paclitaxel is the first-line chemotherapy option, but its treatment is often associated with early discontinuation of therapy due to the development of resistance and/or precipitation of severe side effects. In the quest to establish a suitable combination therapy with a low dose of paclitaxel, we explored rottlerin (a pure and characterized phytoconstituent from Mallotus philippensis) because of its multifaceted pharmacological actions against cancer. The study was performed to assess the therapeutic effects of rottlerin (5-20 mg/kg) with a low dose of paclitaxel (5 mg/kg) using a highly aggressive mouse mammary carcinoma model. Rottlerin augmented the paclitaxel effect by reducing tumor burden as well as metastatic lung nodules formation. Rottlerin in combination with paclitaxel remarkably altered the expression of vital epithelial-mesenchymal transition (EMT) markers such as E-cadherin, Snail 1, & Vimentin and thus improved the anti-metastatic efficacy of paclitaxel. Significant attenuation of anti-apoptotic protein (Bcl-2) along with amplification of pro-apoptotic (cleaved PARP) marker confers that rottlerin could ameliorate the pro-apoptotic potential of paclitaxel. In this study, a rational combination of rottlerin and paclitaxel treatment curtailed CYP2J2 expression and epoxyeicosatrienoic acids (EETs) levels, responsible for restrain tumor growth and metastasis. Additionally, rottlerin lessened paclitaxel treatment-mediated hematological alterations and prevented paclitaxel treatment-linked key serum biochemical changes related to organ toxicities. These rottlerin treatment-mediated protective changes are closely associated with the lower paclitaxel accumulation in the corresponding tissues. Rottlerin caused significant pharmacokinetic interaction with paclitaxel to boost the plasma level of paclitaxel in a typical mouse model and possibly helpful towards the use of a low dose of paclitaxel in combination. Overall, it can be stated that rottlerin has significant potential to augment the anti-metastatic efficacy of paclitaxel via impeding EMT activation along with attenuating its treatment-associated toxicological alterations. Hence, rottlerin has significant potential to explore further as a suitable neoadjuvant therapy with paclitaxel against TNBC.

The Impact of obesity and diabetes mellitus on pancreatic cancer: Molecular mechanisms and clinical perspectives

The incidence of obesity and type 2 diabetes (T2DM) in the Western world has increased dramatically during the recent decades. According to the American Cancer Society, pancreatic cancer (PC) is the fourth leading cause of cancer‐related death in the United States. The relationship among obesity, T2DM and PC is complex. Due to increase in obesity, diabetes, alcohol consumption and sedentary lifestyle, the mortality due to PC is expected to rise significantly by year 2040. The underlying mechanisms by which diabetes and obesity contribute to pancreatic tumorigenesis are not well understood. Furthermore, metabolism and microenvironment within the pancreas can also modulate pancreatic carcinogenesis. The risk of PC on a population level may be reduced by modifiable lifestyle risk factors. In this review, the interactions of diabetes and obesity to PC development were summarized, and novel strategies for the prevention and treatment of diabetes and PC were discussed.

Multiple mechanisms of Rottlerin toxicity in A375 melanoma cells

Rottlerin is a cytostatic and cytotoxic drug in a variety of cancer cells. Our previous experience demonstrated that depending upon the genetic/biochemical background of cancer cells, rottlerin is able to induce both apoptotic and autophagic cell death, or dramatically disturb protein homeostasis leading to lethal cellular atrophy. In the current study, we investigated the cytotoxic effects and mechanisms of rottlerin against human amelanotic A375 melanoma cells. In this cell line, rottlerin exhibits its main and newest cytotoxic properties, that is, growth arrest, apoptosis induction, and translation shutoff. In fact, the drug, time-, and dose-dependently, markedly inhibited cell proliferation through cyclin D1 downregulation and induced apoptotic cell death as early as after 18 h treatment. Mechanistically, rottlerin triggered apoptosis by both intrinsic and extrinsic pathways. Both pathways are likely activated by the downregulation of the antiapoptotic B-cell lymphoma 2 (Bcl-2) protein, which simultaneously affects mitochondrial and endoplasmic reticulum (ER) membranes stability. Concomitantly to extrinsic apoptosis induction, the rottlerin-activated ER stress/eukaryotic initiation factor 2 (eIF2) α axis blocked the translational apparatus. The altered proteostasis precluded the complete cells' rescue from death in the presence of apoptosis inhibitors.

High-level Sp1 is Associated with Proliferation, Invasion, and Poor Prognosis in Astrocytoma

Astrocytoma is the most common and the most lethal primary brain tumor in adults. Grade IV glioblastoma is usually refractory to currently available surgical, chemotherapeutic, and radiotherapeutic treatments. The Specificity protein 1 (Sp1) transcription factor is known to regulate tumorigenesis in many cancers. The aim of this study was to investigate the clinicopathologic role of Sp1 protein in the carcinogenesis of astrocytoma. This study analyzed 98 astrocytoma cases treated at Kaohsiung Medical University Hospital during 2002-2012. Clinicopathologic parameters associated with Sp1 were analyzed by chi-square test, Kaplan-Meier analysis, and Cox regression analyses. In vitro proliferation, invasion, and migration were compared between non-siRNA groups and Sp1 siRNA groups. In glioblastoma cells treated with Sp1 siRNA, Western blot was also used to detect expressions of Sp1, Ki-67, VEGF, cyclin D1, E-cadherin, cleaved caspase-3 and Bax proteins. Expression of Sp1 was significantly associated with WHO grade (p = 0.005) and with overall survival time (p < 0.001). Multivariate analysis further revealed that prognosis of astrocytoma was significantly associated with Sp1 expression (p = 0.036) and IDH-1 expression (p < 0.001). In vitro silencing of Sp1 downregulated Sp1, Ki-67, and cyclin D1 but upregulated E-cadherin, Bax, and cleaved caspase-3. These data suggest that Sp1 is a potential prognostic marker and therapeutic target in astrocytoma.

Synthetic Triterpenoid CDDO-Me Inhibits Proliferation, Migration, and Invasion in GBM8401 and GBM8901

Objectives:

We determined the anticancer potency of CDDO-Me in glioblastoma cell lines and the underlying mechanisms in vitro.

Summary:

CDDO-Me is a synthetic triterpenoid with more potent anticancer and cancer preventive actions compared with the original triterpenoid CDDO.

Methods:

Two glioblastoma cell lines, GBM8401 and GBM8901, were utilized to test the effect of CDDO-Me on cell viability, cell migration, and cell invasion using the MTT, wound healing, and transwell migration assays, respectively. Additionally, Western blotting was used to determine the protein expression levels of N-cadherin, cyclin D1, and vascular endothelial growth factor.

Results:

At nanomolar concentrations, CDDO-Me inhibited proliferation, migration, and invasion in both cell lines. In addition, CDDO-Me exhibited a dose-dependent downregulation in the protein levels of N-cadherin, cyclin D1, and vascular endothelial growth factor in GBM8401 and GBM8901 cells.

Conclusions:

CDDO-Me exhibited anticancer effects at low nanomolar concentrations and should be considered as a potential chemotherapeutic agent for glioblastoma.

Inhibition of pancreatic cancer stem cell characteristics by α-Mangostin: Molecular mechanisms involving Sonic hedgehog and Nanog

The current investigation was intended to elucidate the molecular mechanism of α‐Mangostin in the regulation of pancreatic cancer stem cell (CSC) characteristics. Here, we demonstrate that α‐Mangostin inhibited cell proliferation in pancreatic CSCs and cancer cell lines while it showed no effect on human pancreatic normal ductal epithelial cells. Also, α‐Mangostin inhibited colony formation and induced apoptosis in these cells. Further, α‐Mangostin inhibited the self‐renewal capacity of CSCs isolated from human primary tumours and Kras^G12D mice. Furthermore, α‐Mangostin inhibited the invasive and metastatic ability of pancreatic CSCs by suppressing the epithelial‐to‐mesenchymal transition (EMT) via up‐regulation of E‐cadherin and down‐regulation of mesenchymal phenotype by inhibiting N‐cadherin, Snail and Slug expression. Interestingly, the pluripotency maintaining factors and CSC markers were inhibited by α‐Mangostin thus suggesting that α‐Mangostin can target CSCs to inhibit pancreatic cancer effectively. Gli signalling plays a crucial role in the self‐renewal and pluripotency of CSCs. α‐Mangostin inhibited the Gli transcription and the expression of Gli target genes (Nanog, Oct4, c‐Myc, Sox‐2 and KLF4) in CSCs. Using ChIP assay, we demonstrated that Nanog could directly bind to promoters of Cdk2, Cdk6, FGF4, c‐Myc and α‐Mangostin inhibited Nanog binding to these promoters. Conversely, the inhibitory effects of the α‐Mangostin on CSC proliferation and Gli or Nanog transcription and their targets were abrogated by either enforced activation of sonic hedgehog (Shh) or by the overexpression of Nanog. Taken together, our studies suggest that α‐Mangostin may act as Gli inhibitor and establishes the pre‐clinical significance of α‐Mangostin for the prevention and treatment of pancreatic cancer.

Rottlerin inhibits cell growth and invasion via down-regulation of EZH2 in prostate cancer

Rottlerin as a natural agent, which is isolated from Mallotus philippinensis, has been identified to play a critical role in tumor inhibition. However, the molecular mechanism of rottlerin-mediated anti-tumor activity is still ambiguous. It has been reported that EZH2 exhibits oncogenic functions in a variety of human cancers. Therefore, inhibition of EZH2 could be a promising strategy for the treatment of human cancers. In this study, we aim to explore whether rottlerin could inhibit tumorigenesis via suppression of EZH2 in prostate cancer cells. Multiple approaches such as FACS, Transwell invasion assay, RT-PCR, Western blotting, and transfection were performed to determine our aim. We found that rottlerin treatment led to inhibition of cell growth, migration and invasion, but induction of apoptosis in prostate cancer cells. Importantly, we defined that rottlerin decreased the expression of EZH2 and H3K27me3 in prostate cancer cells. Moreover, overexpression of EZH2 abrogated the rottlerin-induced inhibition of cell growth, migration, and invasion in prostate cancer cells. Consistently, down-regulation of EZH2 enhanced rottlerin-triggered anti-tumor function. Collectively, our work demonstrated that rottlerin exerted its tumor suppressive function via inhibition of EZH2 expression in prostate cancer cells. Our findings indicated that rottlerin might be a potential therapeutic compound for treating patients with prostate cancer.

Rottlerin inhibits cell growth and invasion via down-regulation of Cdc20 in glioma cells

Rottlerin, isolated from a medicinal plant Mallotus phillippinensis, has been demonstrated to inhibit cellular growth and induce cytoxicity in glioblastoma cell lines through inhibition of calmodulin-dependent protein kinase III. Emerging evidence suggests that rottlerin exerts its antitumor activity as a protein kinase C inhibitor. Although further studies revealed that rottlerin regulated multiple signaling pathways to suppress tumor cell growth, the exact molecular insight on rottlerin-mediated tumor inhibition is not fully elucidated. In the current study, we determine the function of rottlerin on glioma cell growth, apoptosis, cell cycle, migration and invasion. We found that rottlerin inhibited cell growth, migration, invasion, but induced apoptosis and cell cycle arrest. Mechanistically, the expression of Cdc20 oncoprotein was measured by the RT-PCR and Western blot analysis in glioma cells treated with rottlerin. We observed that rottlerin significantly inhibited the expression of Cdc20 in glioma cells, implying that Cdc20 could be a novel target of rottlerin. In line with this, over-expression of Cdc20 decreased rottlerin-induced cell growth inhibition and apoptosis, whereas down-regulation of Cdc20 by its shRNA promotes rottlerin-induced anti-tumor activity. Our findings indicted that rottlerin could exert its tumor suppressive function by inhibiting Cdc20 pathway which is constitutively active in glioma cells. Therefore, down-regulation of Cdc20 by rottlerin could be a promising therapeutic strategy for the treatment of glioma.

Rottlerin exerts its anti-tumor activity through inhibition of Skp2 in breast cancer cells

Studies have investigated the tumor suppressive role of rottlerin in carcinogenesis. However, the molecular mechanisms of rottlerin-induced anti-tumor activity are largely unclear. Skp2 (S-phase kinase associated protein 2) has been validated to play an oncogenic role in a variety of human malignancies. Therefore, inactivation of Skp2 could be helpful for the treatment of human cancers. In the current study, we explore whether rottlerin could inhibit Skp2 expression, leading to inhibition of cell growth, migration and invasion in breast cancer cells. We found that rottlerin treatment inhibited cell growth, induced apoptosis and cell cycle arrest. We also revealed that rottlerin suppressed cell migration and invasion in breast cancer cells. Mechanically, we observed that rottlerin significantly down-regulated the expression of Skp2 in breast cancer cells. Importantly, overexpression of Skp2 abrogated rottlerin-mediated tumor suppressive activity, whereas down-regulation of Skp2 enhanced rottlerin-triggered anti-tumor function. Strikingly, we identified that rottlerin exhibited its anti-tumor potential partly through inactivation of Skp2 in breast cancer. Our findings indicate that rottlerin could be a potential safe agent for the treatment of breast cancer.

Rottlerin as a therapeutic approach in psoriasis: Evidence from in vitro and in vivo studies

Rottlerin is a natural polyphenolic compound that was initially indicated as a PKCδ inhibitor. However, it was recently revealed that it may target a number of molecules and have biological effects on various cell types and is considered as a possible agent for tumor and cell proliferative diseases. Psoriasis is a chronic inflammatory cutaneous disorder with undefined etiology and is characterized by abnormal cellular proliferation, angiogenesis, and inflammation. Therefore, this paper investigates the regulatory effects of rottlerin on normal human epidermal keratinocytes (NHEKs) and imiquimod (IMQ)-induced psoriasiform (IPI) lesions. In vitro results showed that rottlerin inhibited cell proliferation in NHEKs through growth arrest and NFκB inhibition. It may also induce apoptosis in an autophagy-dependent pathway. We found that rottlerin inhibited human microvascular endothelial cells tube formation on matrigel. Rottlerin also decreased the cell senescence of keratinocytes and intracellular ROS generation, which indicated its antioxidant effect. We also showed that rottlerin affects the expression of keratinocyte proliferation biomarkers. In 12-O-tetradecanoylphorbol13-acetate (TPA)-induced keratinocytes, rottlerin significantly inhibited the expression of the induced pro-inflammatory cytokines in keratinocytes. An animal experiment provided the corresponding evidence based on this evidence in vitro, by using IPI model, we found that rottlerin could relieve the psoriasiform of BALB/c mice by inhibiting keratinocyte proliferation, inflammatory cell infiltration, and vascular proliferation. In conclusion, our results suggest that rottlerin may prove useful in the development of therapeutic agents against psoriasis. However, the deep mechanism still requires further study.

Rottlerin as a novel chemotherapy agent for adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare, but aggressive endocrine malignancy with a generally poor clinical outcome. There is no effective therapy for advanced and metastatic ACC. In our study, we found that an existing drug (rottlerin) exerted its tumour-suppressive function in ACC. Specifically, rottlerin inhibited cellular proliferation of ACC cell lines (NCI-H295R and SW-13) in a dose- and time-dependent manner. We also found that rottlerin induced cell apoptosis and promoted G0/G1 cell cycle arrest in ACC cell lines. The cellular migration and invasion of ACC cell lines were decreased after treatment with rottlerin. Further, the molecular expression of lipoprotein receptor related protein 6 (LRP6) and β-catenin were down-regulated in rottlerin-treated ACC cells, which indicated that Wnt/β-catenin signaling was involved in the tumour-suppressive function of rottlerin. To further confirm the anti-tumour function of rottlerin, a nude mouse ACC xenograft model was used. The xenograft growth curves and TUNEL assays demonstrated that rottlerin inhibited proliferation and induced apoptosis in the ACC xenograft model. Furthermore, we verified that rottlerin down-regulated the expression of LRP6 and β-catenin in vivo. The ACC cell line and xenograft mouse model data indicated that rottlerin significantly inhibited proliferation and induced apoptosis of ACC cells, likely via suppression of the Wnt/β-catenin signaling pathway. Our study indicated the potential therapeutic utility of rottlerin as a novel and potential chemotherapeutic agent for ACC.

Inhibition of Notch-1 pathway is involved in rottlerin-induced tumor suppressive function in nasopharyngeal carcinoma cells

Recent studies have revealed that rottlerin is a natural chemical drug to exert its anti-cancer activity. However, the molecular mechanisms of rottlerin-induced tumor suppressive function have not been fully elucidated. Notch signaling pathway has been characterized to play a crucial role in tumorigenesis. Therefore, regulation of Notch pathway could be beneficial for the treatment of human cancer. The aims of our current study were to explore whether rottlerin could suppress Notch-1 expression, which leads to inhibition of cell proliferation, migration and invasion in nasopharyngeal carcinoma cells. We performed several approaches, such as CTG, Flow cytometry, scratch healing assay, transwell and Western blotting. Our results showed that rottlerin treatment inhibited cell growth, migration and invasion, and triggered apoptosis, and arrested cell cycle to G1 phase. Moreover, the expression of Notch-1 was obvious decreased in nasopharyngeal carcinoma cells after rottlerin treatment. Importantly, overexpression of Notch-1 promoted cell growth and invasion, whereas down-regulation of Notch-1 inhibited cell growth and invasion in nasopharyngeal carcinoma cells. Notably, we found the over-expression of Notch-1 could abrogate the anti-cancer function induced by rottlerin. Strikingly, our study implied that Notch-1 could be a useful target of rottlerin for the prevention and treatment of human nasopharyngeal carcinoma.

α-Mangostin-encapsulated PLGA nanoparticles inhibit pancreatic carcinogenesis by targeting cancer stem cells in human, and transgenic (Kras(G12D), and Kras(G12D)/tp53R270H) mice

Activation of sonic hedgehog (Shh) in cancer stem cell (CSC) has been demonstrated with aggressiveness of pancreatic cancer. In order to enhance the biological activity of α-mangostin, we formulated mangostin-encapsulated PLGA nanoparticles (Mang-NPs) and examined the molecular mechanisms by which they inhibit human and KC mice (Pdx^Cre;LSL-Kras^G12D) pancreatic CSC characteristics in vitro, and pancreatic carcinogenesis in KPC (Pdx^Cre;LSLKras^G12D;LSL-Trp53^R172H) mice. Mang-NPs inhibited human and Kras^G12D mice pancreatic CSC characteristics in vitro. Mang-NPs also inhibited EMT by up-regulating E-cadherin and inhibiting N-cadherin and transcription factors Slug, and pluripotency maintaining factors Nanog, c-Myc, and Oct4. Furthermore, Mang-NPs inhibited the components of Shh pathway and Gli targets. In vivo, Mang-NPs inhibited the progression of pancreatic intraneoplasia to pancreatic ductal adenocarcinoma and liver metastasis in KPC mice. The inhibitory effects of Mang-NPs on carcinogenesis in KPC mice were associated with downregulation of pluripotency maintaining factors (c-Myc, Nanog and Oct4), stem cell markers (CD24 and CD133), components of Shh pathway (Gli1, Gli2, Patched1/2, and Smoothened), Gli targets (Bcl-2, XIAP and Cyclin D1), and EMT markers and transcription factors (N-cadherin, Slug, Snail and Zeb1), and upregulation of E-cadherin. Overall, our data suggest that Mang-NPs can inhibit pancreatic cancer growth, development and metastasis by targeting Shh pathway.

PI3K/AKT/mTOR and sonic hedgehog pathways cooperate together to inhibit human pancreatic cancer stem cell characteristics and tumor growth

Cancer stem cells (CSCs) play major roles in cancer initiation, progression, and metastasis. It is evident from growing reports that PI3K/Akt/mTOR and Sonic Hedgehog (Shh) signaling pathways are aberrantly reactivated in pancreatic CSCs. Here, we examined the efficacy of combining NVP-LDE-225 (PI3K/mTOR inhibitor) and NVP-BEZ-235 (Smoothened inhibitor) on pancreatic CSCs characteristics, microRNA regulatory network, and tumor growth. NVP-LDE-225 co-operated with NVP-BEZ-235 in inhibiting pancreatic CSC's characteristics and tumor growth in mice by acting at the level of Gli. Combination of NVP-LDE-225 and NVP-BEZ-235 inhibited self-renewal capacity of CSCs by suppressing the expression of pluripotency maintaining factors Nanog, Oct-4, Sox-2 and c-Myc, and transcription of Gli. NVP-LDE-225 co-operated with NVP-BEZ-235 to inhibit Lin28/Let7a/Kras axis in pancreatic CSCs. Furthermore, a superior interaction of these drugs was observed on spheroid formation by pancreatic CSCs isolated from Pan^kras/p53 mice. The combination of these drugs also showed superior effects on the expression of proteins involved in cell proliferation, survival and apoptosis. In addition, NVP-LDE-225 co-operated with NVP-BEZ-235 in inhibiting EMT through modulation of cadherin, vimentin and transcription factors Snail, Slug and Zeb1. In conclusion, these data suggest that the combined inhibition of PI3K/Akt/mTOR and Shh pathways may be beneficial for the treatment of pancreatic cancer.

Combined targeting of EGFR/HER promotes anti-tumor efficacy in subsets of KRAS mutant lung cancer resistant to single EGFR blockade

KRAS is a frequently mutated oncogene in lung cancer and among the most refractory to EGFR targeted therapy. Recently, preclinical evidence in pancreatic cancer has demonstrated that mutant KRAS can be regulated by EGFR. However, the distinct correlation between the EGFR/HER family members and mutant KRAS has not been investigated. Here, we show that non-small cell lung cancer cell lines harboring differing isoforms of mutant KRAS, can be broadly divided into EGFR/HER dependent and EGFR/HER independent groups. Combined therapeutic targeting of EGFR, HER2 and HER3 in isoforms regulated by extracellular growth signals promotes in vitro and in vivo efficacy. We also provide evidence that depletion of EGFR via RNA interference specifically abolishes the EGFR/KRAS interaction in the dependent subset. Taken together, these findings suggest that upstream inhibition of the EGFR/HER receptors may be effective in treating a subset of KRAS mutant lung cancers.

Expression of PTEN and KAI1 tumor suppressor genes in pancreatic carcinoma and its association with different pathological factors

Pancreatic carcinoma is a common cancer type with a poor prognosis. The aim of the present study was to examine the expression of tumor suppressor genes phosphatase and tensin homolog deleted in chromosome 10 (PTEN) and KAI1 in pancreatic carcinoma and its association with clinical pathological factors. A total of 50 hospitalized cases of pancreatic cancer including 28 males and 22 females aged 31-82 years were included in the present study. Ten cases of normal pancreatic tissue were obtained from cadavers and served as the controls. The pancreatic specimens were embedded in paraffin blocks and slides were prepared for immunohistochemical analysis to determine the expression of PTEN and KAI1 in normal pancreatic tissue and pancreatic carcinoma samples. The positive expression rate of PTEN in the normal pancreatic tissue was higher than that in pancreatic carcinoma (P<0.05), while the positive expression rate of KAI1 in the normal pancreatic tissue was lower than that in pancreatic carcinoma (P<0.05). Pathological factors such as clinical stage of disease, histological grade and the presence or absence of lymphatic metastasis significantly affected the expression of PTEN and KAI1 (P<0.05). In conclusion, the positive expression of PTEN and KAI1 in pancreatic carcinoma is closely associated with the development of pancreatic carcinoma.

Anthothecol-encapsulated PLGA nanoparticles inhibit pancreatic cancer stem cell growth by modulating sonic hedgehog pathway

Anthothecol, a limonoid isolated from plant Khaya anthotheca (Meliaceae), is an antimalarial compound. The objectives of this study were to examine the molecular mechanisms by which anthothecol-encapsulated PLGA-nanoparticles (Antho-NPs) regulate the behavior of pancreatic cancer stem cells (CSCs). Antho-NPs inhibited cell proliferation and colony formation, and induced apoptosis in pancreatic CSCs and cancer cell lines, but had no effects on human normal pancreatic ductal epithelial cells. Antho-NPs inhibited self-renewal capacity of pancreatic CSCs isolated from human and Kras(G12D) mice. Furthermore, antho-NPs suppressed cell motility, migration and invasion by up-regulating E-cadherin and inhibiting N-cadherin and Zeb1. In addition, Antho-NPs inhibited pluripotency maintaining factors and stem cell markers, suggesting their inhibitory role on CSC population. Anthothecol disrupted binding of Gli to DNA, and inhibited Gli transcription and Gli target genes. Our studies establish preclinical significance of Antho-NPs for the treatment and/or prevention of pancreatic cancer.

FROM THE CLINICAL EDITOR

Despite medical advances, the prognosis of pancreatic cancer remains poor. The search for an effective treatment has been under intensive research for some time. In this article, the authors investigated the efficacy and mechanism of anthothecol (an antimalarial compound), encapsulated by PLGA nanoparticles (Antho-NPs), against pancreatic cancer cell lines. It was found that Antho-NPs acted via the Sonic hedgehog signaling pathway and inhibited cancer stem cell growth. These results have provided important basis for further clinical trials.

Antiproliferative Effect of Rottlerin on Sk-Mel-28 Melanoma Cells

Melanoma is the most aggressive and chemoresistant form of skin cancer. Mutated, constitutively active B-RAF is believed to play a crucial role, although the selective B-RAF inhibition has shown poor clinical success, since phenomena of resistance usually occur, likely arising from additional genetic aberrations, such as loss of function of p53 and PTEN, overexpression of cyclin D1, hyperactivation of NF-κB, and downregulation of p21/Cip1. Since all of them are present in the Sk-Mel-28 melanoma cells, this cell line could be an ideal, albeit hard to study, model to develop new therapeutic strategies. In the current study, we tested the cytostatic action of Rottlerin on Sk-Mel-28 melanoma cells, on the basis of the known Rottlerin effects on the main proliferative signaling pathways. We presented evidence that the drug inhibits cell growth by an Akt- and p21/Cip1-independent mechanism, involving the dual inhibition of ERK and NF-κB and downregulation of cyclin D1. In addition, we found that Rottlerin increases ERK phosphorylation, but, surprisingly, this resulted in decreased ERK activity. Pull-down experiments, using Rottlerin-CNBr-conjugated Sepharose beads, revealed that Rottlerin binds to ERK, independently from its phosphorylation status. This direct interaction could in part explain the paradoxical blockage of ERK downstream signaling and growth arrest.

We would like to dedicate this paper to the memory of our friend and colleague, prematurely deceased, Claudia Torricelli, who actively contributed to this project

Knockdown of Rho-associated protein kinase 1 suppresses proliferation and invasion of glioma cells

Rho-associated protein kinase 1 (ROCK1), a serine/threonine protein kinase, affects cell invasion and migration by changing the status of the cytoskeleton. In recent years, ROCK1 was found to be overexpressed in a variety of tumors. However, the information of ROCK1 in glioma still remains elusive. In our study, the expression of ROCK1 in glioma tissues was examined by real-time PCR and the relationship between ROCK1 expression and clinical characteristics of patients with glioma was also analyzed. With the inhibition of ROCK1 expression by RNAi, the effects of ROCK1 on biological behaviors of glioma cells including cell viability, cell cycle, and cell invasion were probed in the U251 cell line by methyl thiazolyl tetrazolium (MTT) assay, flow cytometer analysis, and Transwell invasion experiment. In addition, the effects of ROCK1 on the regulation of Ki67, cyclin D1, matrix metalloproteinases 9 (MMP9), and E-cadherin were also investigated. The results indicated that ROCK1 messenger RNA (mRNA) was increased significantly compared to that in the adjacent normal tissue (P < 0.05) and the expression level of ROCK1 mRNA in high-grade malignant glioma tissue was significantly higher than that in low-grade malignant glioma tissue (P < 0.05). MTT assay and flow cytometer analysis revealed that the cell viability and cell proliferation in the ROCK1 small interfering RNA (siRNA) transfection group were markedly lower than those in the blank or negative control group (P < 0.05), and no obvious differences were found between the blank group and negative control group. The Transwell invasion experiments showed that the invasive ability of U251 cells in the ROCK1 siRNA transfection group was obviously lower than that in the blank or negative control group (P < 0.05), and there were no visible differences between the blank group and negative control group. Western blot demonstrated that the protein levels of Ki67, cyclin D1, and MMP9 in the ROCK1 siRNA transfection group were distinctly lower than those in the blank or negative control group (P < 0.05) and that the protein level of E-cadherin displayed an opposite variation (P < 0.05). In summary, the expressions of ROCK1 in glioma tissue were visibly upregulated and the increase of ROCK1 had a positive correlation with the malignant grade of glioma. The results implied that the proliferation and metastasis of the glioma cell could be inhibited by suppressing the expression of ROCK1, and our findings would provide a new target for intervention and treatment of glioma.

Dialysis encephalopathy: precipitating factors and improvement in prognosis

Cancer stem cells (CSCs) contribute to the initiation, recurrence, and metastasis of cancer; however, there are still no drugs targeting CSCs in clinical application. There are several signaling pathways playing critical roles in CSC progression, such as the Wnt, Hedgehog, Notch, Hippo, and autophagy signaling pathways. Additionally, targeting the ferroptosis signaling pathway was recently shown to specifically kill CSCs. Therefore, targeting these pathways may suppress CSC progression. The structure of small-molecule drugs shows a good spatial dispersion, and its chemical properties determine its good druggability and pharmacokinetic properties. These characteristics make small-molecule drugs show a great advantage in drug development, which is increasingly popular in the market. Thus, in this review, we will summarize the current researches on the small-molecule compounds suppressing CSC progression, including inhibitors of Wnt, Notch, Hedgehog, and autophagy pathways, and activators of Hippo and ferroptosis pathways. These small-molecule compounds emphasize CSC importance in tumor progression and propose a new strategy to treat cancer in clinic via targeting CSCs.