Anti-Cancer Effect and the Underlying Mechanisms of Gypenosides on Human Colorectal Cancer SW-480 Cells

Background

Gypenosides (Gyp), the main components from Gynostemma pentaphyllum Makino, are widely used in traditional Chinese medicine. The present study aimed to investigate the anti-cancer effect and the underlying mechanisms of Gyp on human colorectal cancer cells SW-480.

Materials and Methods

The inhibitory effect of Gyp on SW-480 cells was evaluated by MTT assay. Apoptotic cell death was detected by nuclear Hoechst 33342 staining and DNA fragmentation analysis. Apoptosis was analyzed using Annexin V-PE/7-amino-actinomycin D staining. Cell membrane integrity was evaluated with flow cytometry following PI staining. Changes of mitochondrial membrane potential (Δψ _m) were detected through flow cytometry analysis of rhodamine 123 (Rh123). The role of reactive oxygen species (ROS) in Gyp induced cell death was investigated by intracellular ROS generation and general ROS scavenger. Wound-healing assay was carried out to investigate Gyp-inhibited migration of SW-480 cells in vitro. Additionally, the alterations in F-actin microfilaments were analyzed by FITC-labeled phalloidin toxin staining and the morphological changes were evaluated under scanning electron microscope (SEM).

Results

After the Gyp treatment, the plasma membrane permeability of SW-480 cell was increased, Δψ _m was decreased significantly, the level of intracellular ROS level was increased, DNA fragmentation and apoptotic morphology were observed. Cells treated with Gyp exert serious microfilament network collapse as well as the significant decrease in the number of microvilli. Gyp induced the changes of cell viability, cell migration, intracellular ROS generation and nuclear morphology were alleviated obviously by NAC.

Conclusion

The results in this study implied that ROS play an important role in Gyp induced cell toxicity and apoptosis, and the mitochondria damage may be upstream of ROS generation post Gyp treatment. The findings of the present study provide new evidences for anti-tumor mechanisms by which Gyp induces apoptosis in vitro.     

Investigating Migration Inhibition and Apoptotic Effects of Fomitopsis pinicola Chloroform Extract on Human Colorectal Cancer SW-480 Cells

Background

Fomitopsis pinicola (Sw. Ex Fr.m) Karst (FPK) which belongs to the Basidiomycota fungal class is one of the most popular medical fungi in China. It has been used for many diseases: cancer, heart diseases, diabetes and so on. However, little study on the pro-apoptotic effect and migration inhibition of FPK chloroform extract (FPKc) has been reported and the possible involved mechanism has not been illuminated.

Methodology/Principal Findings

Chemical analysis was performed by HPLC which showed ergosterol (ES) concentration was 105 µg/mg. MTT assay revealed that FPKc could selectively inhibit SW-480 cells viability with the IC₅₀ of 190.28 µg/ml. Wound healing and transwell assay indicated that FPKc could inhibit the migration of SW-480 cells obviously, FPKc could also dramatically decreased the matrix metalloproteinases-2, 9 (MMP-2 and MMP-9) expression. Annexin V–FITC/PI staining, nuclear Hoechst 33342 staining and DNA fragmentation analysis revealed that FPKc and ES could induce SW-480 cells apoptosis. The apoptosis process closely involved in ROS accumulation and depletion of GSH, activation of caspase 3, poly (ADP-ribose) polymerase (PARP) degradation. FPKc could also up-regulate P53 expression and thus lead to G1 phase arrest. When SW-480 cells were pretreated with N-acetylcysteine (NAC), the ROS generation, cell viability and apoptotic ratio were partially declined, which indicated that ROS was vertical in the pro-apoptosis process induced by FPKc. Moreover, in the whole process, ES which has been previously found in FPKc had the similar effect to FPKc. Thus we could conclude that ES, as one of the highest abundant components in FPKc, might also be one of the active constituents.

Conclusion/Significance

FPKc could inhibit the migration of SW-480 cells, induce SW-480 cells G1 phase arrest and cause ROS-mediated apoptosis effect. And ES might be one of the effective constituents in the whole process.     

Ketamine Causes Mitochondrial Dysfunction in Human Induced Pluripotent Stem Cell-Derived Neurons

Purpose

Ketamine toxicity has been demonstrated in nonhuman mammalian neurons. To study the toxic effect of ketamine on human neurons, an experimental model of cultured neurons from human induced pluripotent stem cells (iPSCs) was examined, and the mechanism of its toxicity was investigated.

Methods

Human iPSC-derived dopaminergic neurons were treated with 0, 20, 100 or 500 μM ketamine for 6 and 24 h. Ketamine toxicity was evaluated by quantification of caspase 3/7 activity, reactive oxygen species (ROS) production, mitochondrial membrane potential, ATP concentration, neurotransmitter reuptake activity and NADH/NAD⁺ ratio. Mitochondrial morphological change was analyzed by transmission electron microscopy and confocal microscopy.

Results

Twenty-four-hour exposure of iPSC-derived neurons to 500 μM ketamine resulted in a 40% increase in caspase 3/7 activity (P < 0.01), 14% increase in ROS production (P < 0.01), and 81% reduction in mitochondrial membrane potential (P < 0.01), compared with untreated cells. Lower concentration of ketamine (100 μM) decreased the ATP level (22%, P < 0.01) and increased the NADH/NAD⁺ ratio (46%, P < 0.05) without caspase activation. Transmission electron microscopy showed enhanced mitochondrial fission and autophagocytosis at the 100 μM ketamine concentration, which suggests that mitochondrial dysfunction preceded ROS generation and caspase activation.

Conclusions

We established an in vitro model for assessing the neurotoxicity of ketamine in iPSC-derived neurons. The present data indicate that the initial mitochondrial dysfunction and autophagy may be related to its inhibitory effect on the mitochondrial electron transport system, which underlies ketamine-induced neural toxicity. Higher ketamine concentration can induce ROS generation and apoptosis in human neurons.     

In Vitro Matured Oocytes Are More Susceptible than In Vivo Matured Oocytes to Mock ICSI Induced Functional and Genetic Changes

Background

Concerns regarding the safety of ICSI have been intensified recently due to increased risk of birth defects in ICSI born children. Although fertilization rate is significantly higher in ICSI cycles, studies have failed to demonstrate the benefits of ICSI in improving the pregnancy rate. Poor technical skill, and suboptimal in vitro conditions may account for the ICSI results however, there is no report on the effects of oocyte manipulations on the ICSI outcome.

Objective

The present study elucidates the influence of mock ICSI on the functional and genetic integrity of the mouse oocytes.

Methods

Reactive Oxygen Species (ROS) level, mitochondrial status, and phosphorylation of H2AX were assessed in the in vivo matured and IVM oocytes subjected to mock ICSI.

Results

A significant increase in ROS level was observed in both in vivo matured and IVM oocytes subjected to mock ICSI (P<0.05-0.001) whereas unique mitochondrial distribution pattern was found only in IVM oocytes (P<0.01-0.001). Importantly, differential H2AX phosphorylation was observed in both in vivo matured and IVM oocytes subjected to mock ICSI (P <0.001).

Conclusion

The data from this study suggests that mock ICSI can alter genetic and functional integrity in oocytes and IVM oocytes are more vulnerable to mock ICSI induced changes.     

High Prevalence and Clinical Relevance of Genes Affected by Chromosomal Breaks in Colorectal Cancer

Background

Cancer is caused by somatic DNA alterations such as gene point mutations, DNA copy number aberrations (CNA) and structural variants (SVs). Genome-wide analyses of SVs in large sample series with well-documented clinical information are still scarce. Consequently, the impact of SVs on carcinogenesis and patient outcome remains poorly understood. This study aimed to perform a systematic analysis of genes that are affected by CNA-associated chromosomal breaks in colorectal cancer (CRC) and to determine the clinical relevance of recurrent breakpoint genes.

Methods

Primary CRC samples of patients with metastatic disease from CAIRO and CAIRO2 clinical trials were previously characterized by array-comparative genomic hybridization. These data were now used to determine the prevalence of CNA-associated chromosomal breaks within genes across 352 CRC samples. In addition, mutation status of the commonly affected APC, TP53, KRAS, PIK3CA, FBXW7, SMAD4, BRAF and NRAS genes was determined for 204 CRC samples by targeted massive parallel sequencing. Clinical relevance was assessed upon stratification of patients based on gene mutations and gene breakpoints that were observed in >3% of CRC cases.

Results

In total, 748 genes were identified that were recurrently affected by chromosomal breaks (FDR <0.1). MACROD2 was affected in 41% of CRC samples and another 169 genes showed breakpoints in >3% of cases, indicating that prevalence of gene breakpoints is comparable to the prevalence of well-known gene point mutations. Patient stratification based on gene breakpoints and point mutations revealed one CRC subtype with very poor prognosis.

Conclusions

We conclude that CNA-associated chromosomal breaks within genes represent a highly prevalent and clinically relevant subset of SVs in CRC.     

Ambient Fine Particulate Matter Suppresses In Vivo Proliferation of Bone Marrow Stem Cells through Reactive Oxygen Species Formation

Aims

Some environmental insults, such as fine particulate matter (PM) exposure, significantly impair the function of stem cells. However, it is unknown if PM exposure could affect the population of bone marrow stem cells (BMSCs). The present study was to investigate the effects of PM on BMSCs population and related mechanism(s).

Main Metheods

PM was intranasally distilled into male C57BL/6 mice for one month. Flow cytometry with antibodies for BMSCs, Annexin V and BrdU ware used to determine the number of BMSCs and the levels of their apoptosis and proliferation in vivo. Phosphorylated Akt (P-Akt) level was determined in the BM cells with western blotting. Intracellular reactive oxygen species (ROS) formation was quantified using flow cytometry analysis. To determine the role of PM-induced ROS in BMSCs population, proliferation, and apotosis, experiments were repeated using N-acetylcysteine (NAC)-treated wild type mice or a triple transgenic mouse line with overexpression of antioxidant network (AON) composed of superoxide dismutase (SOD)1, SOD3, and glutathione peroxidase-1 with decreased in vivo ROS production.

Key Findings

PM treatment significantly reduced BMSCs population in association with increased ROS formation, decreased P-Akt level, and inhibition of proliferation of BMSCs without induction of apoptosis. NAC treatment or AON overexpression with reduced ROS formation effectively prevented PM-induced reduction of BMSCs population and proliferation with partial recovery of P-Akt level.

Significance

PM exposure significantly decreased the population of BMSCs due to diminished proliferation via ROS-mediated mechanism (could be partially via inhibition of Akt signaling).     

Rosiglitazone Promotes Bone Marrow Adipogenesis to Impair Myelopoiesis under Stress

Objective

The therapeutic use of thiazolidinediones (TZDs) causes unwanted hematological side effects, although the underlying mechanisms of these effects are poorly understood. This study tests the hypothesis that rosiglitazone impairs the maintenance and differentiation of hematopoietic stem/progenitor cells, which ultimately leads to hematological abnormalities.

Methods

Mice were fed a rosiglitazone-supplemented diet or a normal diet for 6 weeks. To induce hematopoietic stress, all mice were injected once with 250 mg/kg 5-fluorouracil (5-Fu) intraperitoneally. Next, hematopoietic recovery, hematopoietic stem/progenitor cells (HSPCs) subsets, and myeloid differentiation after 5-Fu treatment were evaluated. The adipogenesis induced by rosiglitazone was assessed by histopathology and oil red O staining. The effect of adipocytes on HSPCs was studied with an in vitro co-culture system.

Results

Rosiglitazone significantly enhanced bone marrow adipogenesis and delayed hematopoietic recovery after 5-Fu treatment. Moreover, rosiglitazone inhibited proliferation of a granulocyte/monocyte progenitor (GMP) cell population and granulocyte/macrophage colony-stimulating factor (GM-CSF) colonies, although the proliferation and mobilization of Lin-c-kit+Sca-1+ cells (LSK) was maintained following hematopoietic stress. These effects could be partially reversed by the selective PPARγ antagonist BADGE. Finally, we demonstrated in a co-culture system that differentiated adipocytes actively suppressed the myeloid differentiation of HSPCs.

Conclusion

Taken together, our results demonstrate that rosiglitazone inhibits myeloid differentiation of HSPCs after stress partially by inducing bone marrow adipogenesis. Targeting the bone marrow microenvironment might be one mechanism by which rosiglitazone impairs stress-induced hematopoiesis.     

The Associations between RNA Splicing Complex Gene SF3A1 Polymorphisms and Colorectal Cancer Risk in a Chinese Population

Background

Aberrant alternative splicing included alterations in components of the mRNA splicing machinery often occurred in colon cancer. However, the role of SF3A1, one key component of the mRNA splicing machinery, on colorectal cancer (CRC) risk was still not elucidated.

Method and Findings

We performed a hospital-based case-control study containing 801 CRC patients and 817 cancer-free controls to examine the association between SF3A1 polymorphisms and CRC risk in a Chinese population. Four candidate SNPs (rs10376, rs5753073, rs2839998 and rs2074733) were selected based on bioinformatics analysis and previous findings. The results showed no significant associations between these SNPs and CRC risk (P > 0.05). Besides, the stratified analysis based on the smoking and alcohol use status obtained no statistically significant results.

Conclusion

Our study was the first one to investigate the association between SF3A1 polymorphisms and CRC risk. The results suggested these four SNPs in SF3A1 were not associated with CRC risk in a Chinese population, however, further more studies are needed to confirm our findings.     

A Two-Gene Blood Test for Methylated DNA Sensitive for Colorectal Cancer

Background

Specific genes are methylated with high frequency in colorectal neoplasia, and may leak into blood. Detection of multiple methylated DNA biomarkers in blood may improve assay sensitivity for colorectal cancer (CRC) relative to a single marker. We undertook a case-control study evaluating the presence of two methylation DNA markers, BCAT1 and IKZF1, in circulation to determine if they were complementary for detection of CRC.

Methods

Methylation-specific PCR assays were developed to measure the level of methylated BCAT1 and IKZF1 in DNA extracted from plasma obtained from colonoscopy-confirmed 144 healthy controls and 74 CRC cases.

Results

DNA yields ranged from 2 to 730 ng/mL plasma (mean 18.6ng/mL; 95% CI 11-26 ng/mL) and did not correlate with gender, age or CRC status. Methylated BCAT1 and IKZF1 DNA were detected in respectively 48 (65%) and 50 (68%) of the 74 cancers. In contrast, only 5 (4%) and 7 (5%) controls were positive for BCAT1 and IKZF1 DNA methylation, respectively. A two-gene classifier model (“either or” rule) improved segregation of CRC from controls, with 57 of 74 cancers (77%) compared to only 11 of 144 (7.6%) controls being positive for BCAT1 and/or IKZF1 DNA methylation. Increasing levels of methylated DNA were observed as CRC stage progressed.

Conclusions

Detection of methylated BCAT1 and/or IKZF1 DNA in plasma may have clinical application as a novel blood test for CRC. Combining the results from the two methylation-specific PCR assays improved CRC detection with minimal change in specificity. Further validation of this two-gene blood test with a view to application in screening is now indicated.     

Fecal Microbiota,Fecal Metabolome,and Colorectal Cancer Interrelations

Background and Aims

Investigation of microbe-metabolite relationships in the gut is needed to understand and potentially reduce colorectal cancer (CRC) risk.

Methods

Microbiota and metabolomics profiling were performed on lyophilized feces from 42 CRC cases and 89 matched controls. Multivariable logistic regression was used to identify statistically independent associations with CRC. First principal coordinate-component pair (PCo1-PC1) and false discovery rate (0.05)-corrected P-values were calculated for 116,000 Pearson correlations between 530 metabolites and 220 microbes in a sex*case/control meta-analysis.

Results

Overall microbe-metabolite PCo1-PC1 was more strongly correlated in cases than in controls (Rho 0.606 vs 0.201, P = 0.01). CRC was independently associated with lower levels of Clostridia, Lachnospiraceae, p-aminobenzoate and conjugated linoleate, and with higher levels of Fusobacterium, Porphyromonas, p-hydroxy-benzaldehyde, and palmitoyl-sphingomyelin. Through postulated effects on cell shedding (palmitoyl-sphingomyelin), inflammation (conjugated linoleate), and innate immunity (p-aminobenzoate), metabolites mediated the CRC association with Fusobacterium and Porphyromonas by 29% and 34%, respectively. Overall, palmitoyl-sphingomyelin correlated directly with abundances of Enterobacteriaceae (Gammaproteobacteria), three Actinobacteria and five Firmicutes. Only Parabacteroides correlated inversely with palmitoyl-sphingomyelin. Other lipids correlated inversely with Alcaligenaceae (Betaproteobacteria). Six Bonferroni-significant correlations were found, including low indolepropionate and threnoylvaline with Actinobacteria and high erythronate and an uncharacterized metabolite with Enterobacteriaceae.

Conclusions

Feces from CRC cases had very strong microbe-metabolite correlations that were predominated by Enterobacteriaceae and Actinobacteria. Metabolites mediated a direct CRC association with Fusobacterium and Porphyromonas, but not an inverse association with Clostridia and Lachnospiraceae. This study identifies complex microbe-metabolite networks that may provide insights on neoplasia and targets for intervention.     

The Prognostic Role of Para-Aortic Lymph Nodes in Patients with Colorectal Cancer: Is It Regional or Distant Disease?

Introduction

Visible para-aortic lymph nodes of ≥2 mm in size are common metastatic patterns of colorectal cancer (CRC) seen on imaging. Their prognostic value, however, remains inconclusive. We aimed to assess the prognostic role of visible para-aortic lymph nodes (PALNs).

Methods

Patients with confirmed pathologic diagnosis of CRC were enrolled. Correlations among clinicopathologic variables were analyzed using the χ² test. The Cox proportional hazards model was applied for univariate and multivariate analyses. Survival was estimated using the Kaplan-Meier method and log-rank test. A prognostic model for visible PALNs in CRC patients was established.

Results

In total, 4527 newly diagnosed CRC patients were enrolled. Patients with visible PALNs had inferior overall survival compared to those without visible PALNs (5-year overall survival, 67% vs. 76%, P = 0.015). Lymphovascular invasion (LVI) (hazard ratio = 1.865, P = 0.015); nodal disease (pN+) status (hazard ratio = 2.099, P = 0.006); elevated preoperative serum carcinoembryonic antigen (CEA) levels (hazard ratio = 2.263, P < 0.001); and visible PALNs ≥10 mm (hazard ratio = 1.638, P = 0.031) were independent prognostic factors for patients with visible PALNs. If each prognostic factor scored one point, 5-year overall survival of lower- (prognostic score 0–1), intermediate- (prognostic score 2), and high- (prognostic score 3–4) risk groups were, 78%. 54%, and 25% respectively (P < 0.001).

Conclusions

The prognostic model, which included LVI, pN+ status, preoperative serum CEA level, and the size of visible PALNs, could effectively distinguish the outcome of patients with visible PALNs.     

Anaplastic Lymphoma Kinase Rearrangement in Digestive Tract Cancer: Implication for Targeted Therapy in Chinese Population

Background

Anaplastic lymphoma kinase (ALK) rearrangements define a subgroup of lung cancer which is eligible to targeted kinase inhibition. The aim of this study is to observe the incidence rate of ALK fusion in a large cohort of Chinese digestive tract cancer patients.

Patients and Methods

Tissue microarray (TMA) was constructed from 808 digestive tract cancer cases, including 169 esophageal squamous cell carcinoma, 182 gastric cancer and 457 colorectal cancer (CRC) cases. We tested all cases for ALK expression via a fully automated immunohistochemistry (IHC) assay. The IHC-positive cases were subjected to fluorescence in situ hybridization (FISH), real-time polymerase chain reaction (qRT-PCR), target gene enrichment and sequencing for confirmation of ALK gene rearrangement and discovery of novel fusion partner.

Results

Among the tested cases, 2 (0.44%) CRC cases showed positive both by IHC and FISH. By qRT-PCR, EML4–ALK fusion was found in one IHC-positive CRC case. In another IHC-positive CRC case, target gene enrichment and sequencing revealed ALK was fused to a novel partner, spectrin beta non-erythrocytic 1 (SPTBN1). One gastric cancer case showed partially positive IHC result, but no fusion was found by FISH and gene sequencing.

Conclusions

The incidence rate of ALK gene fusion in Chinese CRC patients was 0.44%,but not detectable in gastric and esophageal cancers. The novel SPTBN1 -ALK fusion, together with other ALK fusion genes, may become a potential target for anti-ALK therapy.     

N-Acetyl Cysteine Depletes Reactive Oxygen Species and Prevents Dental Monomer-Induced Intrinsic Mitochondrial Apoptosis In Vitro in Human Dental Pulp Cells

Purpose

To investigate the involvement of intrinsic mitochondrial apoptosis in dental monomer-induced cytotoxicity and the influences of N-acetyl cysteine (NAC) on this process.

Methods

Human dental pulp cells (hDPCs) were exposed to several dental monomers in the absence or presence of NAC, and cell viability, intracellular redox balance, morphology and function of mitochondria and key indicators of intrinsic mitochondrial apoptosis were evaluated using various commercial kits.

Results

Dental monomers exerted dose-dependent cytotoxic effects on hDPCs. Concomitant to the over-production of reactive oxygen species (ROS) and depletion of glutathione (GSH), differential changes in activities of superoxide dismutase, glutathione peroxidase, and catalase were detected. Apoptosis, as indicated by positive Annexin V/propidium iodide (PI) staining and activation of caspase-3, was observed after dental monomer treatment. Dental monomers impaired the morphology and function of mitochondria, and induced intrinsic mitochondrial apoptosis in hDPCs via up-regulation of p53, Bax and cleaved caspase-3, and down-regulation of Bcl-2. NAC restored cell viability, relieved oxidative stress and blocked the apoptotic effects of dental monomers.

Conclusions

Dental monomers induced oxidative stress and mitochondrial intrinsic apoptosis in hDPCs. NAC could reduce the oxidative stress and thus protect hDPCs against dental monomer-induced apoptosis.     

c-MYC Copy-Number Gain Is an Independent Prognostic Factor in Patients with Colorectal Cancer

Background

The aim of this study was to determine the incidence and clinicopathological significance of c-MYC gene copy-number (GCN) gain in patients with primary colorectal cancer (CRC).

Methods

The c-MYC GCN was investigated in 367 consecutive CRC patients (cohort 1) by using dual-color silver in situ hybridization. Additionally, to evaluate regional heterogeneity, we examined CRC tissue from 3 sites including the primary cancer, distant metastasis, and lymph-node metastasis in 152 advanced CRC patients (cohort 2). KRAS exons 2 and 3 were investigated for mutations.

Results

In cohort 1, c-MYC gene amplification, defined by a c-MYC:centromere of chromosome 8 ratio ≥ 2.0, was detected in 31 (8.4%) of 367 patients. A c-MYC GCN gain, defined by ≥ 4.0 c-MYC copies/nucleus, was found in 63 (17.2%) patients and was associated with poor prognosis (P = 0.015). Multivariate Cox regression analysis showed that the hazard ratio for c-MYC GCN gain was 2.35 (95% confidence interval, 1.453–3.802; P < 0.001). In a subgroup of stage II-III CRC patients, c-MYC GCN gain was significantly associated with poor prognosis by univariate (P = 0.034) and multivariate (P = 0.040) analyses. c-MYC protein overexpression was observed in 201 (54.8%) out of 367 patients and weakly correlated with c-MYC GCN gain (ρ, 0.211). In cohort 2, the c-MYC genetic status was heterogenous in advanced CRC patients. Discordance between GCN gain in the primary tumor and either distant or lymph-node metastasis was 25.7% and 30.4%, respectively. A similar frequency for c-MYC GCN gain and amplification was observed in CRC patients with both wild-type and mutated KRAS.

Conclusions

c-MYC GCN gain was an independent factor for poor prognosis in consecutive CRC patients and in the stage II-III subgroup. Our findings indicate that the status of c-MYC may be helpful in predicting the patients’ outcome and for managing CRC patients.     

In Vitro and In Vivo Characterization of the Alkaloid Nuciferine

Rationale

The sacred lotus (Nelumbo nucifera) contains many phytochemicals and has a history of human use. To determine which compounds may be responsible for reported psychotropic effects, we used in silico predictions of the identified phytochemicals. Nuciferine, an alkaloid component of Nelumbo nucifera and Nymphaea caerulea, had a predicted molecular profile similar to antipsychotic compounds. Our study characterizes nuciferine using in vitro and in vivo pharmacological assays.

Methods

Nuciferine was first characterized in silico using the similarity ensemble approach, and was followed by further characterization and validation using the Psychoactive Drug Screening Program of the National Institute of Mental Health. Nuciferine was then tested in vivo in the head-twitch response, pre-pulse inhibition, hyperlocomotor activity, and drug discrimination paradigms.

Results

Nuciferine shares a receptor profile similar to aripiprazole-like antipsychotic drugs. Nuciferine was an antagonist at 5-HT_2A, 5-HT_2C, and 5-HT_2B, an inverse agonist at 5-HT₇, a partial agonist at D_2, D₅ and 5-HT₆, an agonist at 5-HT_1A and D₄ receptors, and inhibited the dopamine transporter. In rodent models relevant to antipsychotic drug action, nuciferine blocked head-twitch responses and discriminative stimulus effects of a 5-HT_2A agonist, substituted for clozapine discriminative stimulus, enhanced amphetamine induced locomotor activity, inhibited phencyclidine (PCP)-induced locomotor activity, and rescued PCP-induced disruption of prepulse inhibition without induction of catalepsy.

Conclusions

The molecular profile of nuciferine was similar but not identical to that shared with several approved antipsychotic drugs suggesting that nuciferine has atypical antipsychotic-like actions.     

A Transition Zone Showing Highly Discontinuous or Alternating Levels of Stem Cell and Proliferation Markers Characterizes the Development of PTEN-Haploinsufficient Colorectal Cancer

Background

Stepwise acquisition of oncogene mutations and deletion/inactivation of tumor suppressor genes characterize the development of colorectal cancer (CRC). These genetic events interact with discrete morphologic transitions from hyperplastic mucosa to adenomatous areas, followed by in situ malignant transformation and finally invasive carcinoma. The goal of this study was to identify tissue markers of the adenoma-carcinoma morphogenetic transitions in CRC.

Methods and Findings

We analyzed the patterns of expression of growth regulatory and stem cell markers across these distinct morphologic transition zones in 735 primary CRC tumors. In 202 cases with preserved adenoma-adenocarcinoma transition, we identified, in 37.1% of cases, a zone of adenomatous epithelium, located immediately adjacent to the invasive component, that showed rapidly alternating intraglandular stretches of PTEN+ and PTEN- epithelium. This zone exactly overlapped with similar alternating expression of Ki-67 and inversely with the transforming growth factor-beta (TGF-β) growth regulator SMAD4. These zones also show parallel alternating levels and/or subcellular localization of multiple cancer stem/progenitor cell (CSC) markers, including β-catenin/CTNNB1, ALDH1, and CD44. PTEN was always re-expressed in the invasive tumor in these cases, unlike those with complete loss of PTEN expression. Genomic microarray analysis of CRC with prominent CSC-like expansions demonstrated a high frequency of PTEN genomic deletion/haploinsufficiency in tumors with CSC-like transition zones (62.5%) but not in tumors with downregulated but non-alternating PTEN expression (14.3%). There were no significant differences in the levels of KRAS mutation or CTNNB1 mutation in CSC-like tumors as compared to unselected CRC cases.

Conclusions

In conclusion, we have identified a distinctive CSC-like pre-invasive transition zone in PTEN-haploinsufficient CRC that shows convergent on-off regulation of the PTEN/AKT, TGF-β/SMAD and Wnt/β-catenin pathways. This bottleneck-like zone is usually followed by the emergence of invasive tumors with intact PTEN expression but dysregulated TP53 and uniformly high proliferation rates.