The expression and clinical significance of PI3K, pAkt and VEGF in colon cancer

A network pharmacology approach and experimental validation to investigate the anticancer mechanism and potential active targets of ethanol extract of Wei-Tong-Xin against colorectal cancer through induction of apoptosis via PI3K/AKT signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Wei-Tong-Xin (WTX), derives from the Chinese herbal decoction (CHD) of Wan-Ying-Yuan in ancient China, has been shown to be effective therapeutic herbal decoction for treating gastrointestinal diseases. Present studies have demonstrated that WTX had potential to alleviate the symptoms of gastrointestinal inflammation, gastric ulcer and improve gastric motility.

AIM OF THE STUDY

The study primarily focused on exploring the therapeutic effect and possible pharmacological mechanism of WTX on colorectal cancer (CRC) based on network pharmacology, in vitro and in vivo experiments.

MATERIALS AND METHODS

Firstly, colorectal cancer and WTX associated with targets were searched from GeneCards database and TCM Systems Pharmacology Database and Analysis Platform (TCMSP) respectively. The protein-protein interaction (PPI) network also was constructed to screening key targets. In addition, the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were applied to predict the underlying biological function and mechanism involving in the anti-colorectal cancer effect of WTX. Next, CCK-8, colony formation and transwell assays were performed to verify the influence of proliferation and metastasizing ability of HCT116 cells after treated with WTX. Cell cycle, apoptosis and reactive oxygen species (ROS) were analysis by flow cytometry. Hoechst 33258 staining was conducted to observe nuclear morphology changes. Protein expression of apoptosis and PI3K/AKT signaling as well as mRNA expression of ferroptosis and apoptosis were determined by Western Blotting and RT-qPCR. The effects of WTX and LY294002 combination on the PI3K/Akt/mTOR signaling pathway were measured by Western Blotting. Finally, the xenograft tumor mouse model was established by subcutaneous injection of CT26 cells to measure tumors volume and weight. Hematoxylin and eosin (HE) staining and immunohistochemical analysis were used to observe the pathological changes and the protein expression in tumor tissues.

RESULTS

There were 286 potential treatment targets from 130 bioactive compounds in WTX, 1349 CRC-related targets were identified. Eleven core targets (TP53, AKT1, STAT3, JUN, TNF, HSP90AA1, IL-6, MAPK3, CASP3, EGFR, MYC) were found by PPI network analysis constructed of 142 common targets. The results of KEGG enrichment displayed PI3K/AKT signaling pathway as core pathway. After the treatment of WTX, the inhibitory of viability, metastases and cell cycle arrest at G2/M phase were observed in HCT116 cells. Moreover, WTX induced an increase in the expression of apoptosis proteins (Bak, cytochrome c, cleaved caspase-9/caspase-9 and cleaved caspase-3/caspase-3) and the levels of ROS and MDA, a decrease in the expression of PI3K/AKT signaling related proteins (PI3K, p-PI3K, p-AKT/AKT and p-mTOR/mTOR) and the level of SOD. WTX treatment significantly reduced the tumor weight, increased cleaved caspase-3 positive area and decreased that of ki67 in xenograft mouse model.

CONCLUSION

Through a network pharmacology approach and in vitro experiments, we predicted and verified the effect of WTX on colorectal cancer cells mainly depended on the regulation of intrinsic apoptosis via PI3K/AKT signaling pathway, and further animal experiments proved that WTX has a good anti-colon cancer effect in vivo.

Identification of Kinase Targets for Enhancing the Antitumor Activity of Eribulin in Triple-Negative Breast Cell Lines

Background: Triple-negative breast cancer (TNBC) is the most aggressive molecular subtype of breast cancer, and current treatments are only partially effective in disease control. More effective combination approaches are needed to improve the survival of TNBC patients. Eribulin mesylate, a non-taxane microtubule dynamics inhibitor, is approved by the U.S. Food and Drug Administration to treat metastatic breast cancer after at least two previous chemotherapeutic regimens. However, eribulin as a single agent has limited therapeutic efficacy against TNBC. Methods: High-throughput kinome library RNAi screening, Ingenuity Pathway Analysis, and STRING analysis were performed to identify target kinases for combination with eribulin. The identified combinations were validated using in vivo and ex vivo proliferation assays. Results: We identified 135 potential kinase targets whose inhibition enhanced the antiproliferation effect of eribulin in TNBC cells, with the PI3K/Akt/mTOR and the MAPK/JNK pathways emerging as the top candidates. Indeed, copanlisib (pan-class I PI3K inhibitor), everolimus (mTOR inhibitor), trametinib (MEK inhibitor), and JNK-IN-8 (pan-JNK inhibitor) produced strong synergistic antiproliferative effects when combined with eribulin, and the PI3K and mTOR inhibitors had the most potent effects in vitro. Conclusions: Our data suggest a new strategy of combining eribulin with PI3K or mTOR inhibitors to treat TNBC.

Luteolin Suppresses Three Angiogenesis Modes and Cell Interaction in Uveal Melanoma in Vitro

PURPOSE

Uveal melanoma is a high-vascularized tumor that lacks effective systemic therapies. Most anti-angiogenesis drug therapies only target endothelial cell-dependent angiogenesis but not vasculogenic mimicry (VM), which supplies blood to tumors independent of endothelial cells. Thus, we aimed to explore the inhibitory effects of luteolin on proliferation, migration, invasiveness, angiogenesis, and VM activity of uveal melanoma. We further explored the signaling pathway underlying the mechanism of action of luteolin.

METHODS

Monocultures of uveal melanoma C918 cells, human umbilical vein endothelial cells (HUVECs), and co-cultures of these two cell lines were established. Angiogenesis of HUVECs, VM formation of C918 cells, and the mosaic vessels formed by both cell types were observed under an inverted microscope. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine (EdU), wound scratch, Transwell cell migration, and invasion assays were performed. VEGF levels were detected by ELISA. Western blotting was used to detect the expression of PI3K, p-PI3K P85, Akt, and p-Akt Ser473 proteins.

RESULTS

Luteolin inhibited all three modes of angiogenesis observed in uveal melanoma in vitro. Luteolin effectively inhibited the proliferation, migration, and invasion of C918 cells and proliferation and migration of HUVECs. Furthermore, luteolin could inhibit the interaction between the endothelial cells and C918 cells. VEGF secretion in C918 cells and HUVECs treated with luteolin was inhibited. Luteolin decreased the levels of phosphorylated Akt kinase.

CONCLUSION

We demonstrated the anti-angiogenic effects of luteolin, including against the VM type, in addition to suppressing tumor cell proliferation and migration in vitro. Furthermore, luteolin likely exerts its inhibitory effects via the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway. Luteolin might be an effective therapeutic candidate for treating highly vascularized uveal melanoma tumors.

Neuroprotective Effects of VEGF in the Enteric Nervous System

Although the enteric nervous system (ENS) functions largely autonomously as part of the peripheral nervous system (PNS), it is connected to the central nervous system (CNS) via the gut–brain axis. In many neurodegenerative diseases, pathological changes occur in addition to gastrointestinal symptoms, such as alpha-synuclein aggregates in Parkinson’s disease, which are found early in the ENS. In both the CNS and PNS, vascular endothelial growth factor (VEGF) mediates neuroprotective and neuroregenerative effects. Since the ENS with its close connection to the microbiome and the immune system is discussed as the origin of neurodegenerative diseases, it is necessary to investigate the possibly positive effects of VEGF on enteric neurons. Using laser microdissection and subsequent quantitative RT-PCR as well as immunohistochemistry, for the first time we were able to detect and localize VEGF receptor expression in rat myenteric neurons of different ages. Furthermore, we demonstrate direct neuroprotective effects of VEGF in the ENS in cell cultures. Thus, our results suggest a promising approach regarding neuroprotection, as the use of VEGF (may) prevent neuronal damage in the ENS.

Formulation and Characterization of Doxycycline-Loaded Polymeric Nanoparticles for Testing Antitumor/Antiangiogenic Action in Experimental Colon Cancer in Mice

Nanotherapeutics can enhance the characteristics of drugs, such as rapid systemic clearance and systemic toxicities. Polymeric nanoparticles (PRNPs) depend on dispersion of a drug in an amorphous state in a polymer matrix. PRNPs are capable of delivering drugs and improving their safety. The primary goal of this study is to formulate doxycycline-loaded PRNPs by applying the nanoprecipitation method. Eudragit S100 (ES100) (for DOX-PRNP1) and hydroxypropyl methyl cellulose phthalate HP55 (for DOX-PRNP2) were tested as the drug carrying polymers and the DOX-PRNP2 showed better characteristics and drug release % and was hence selected to be tested in the biological study. Six different experimental groups were formed from sixty male albino mice. 1,2,-Dimethylhydrazine was used for 16 weeks to induce experimental colon cancer. We compared the oral administration of DOX-PRNP2 in doses of 5 and 10 mg/kg with the free drug. Results indicated that DOX-PRNP2 had greater antitumor activity, as evidenced by an improved histopathological picture for colon specimens as well as a decrease in the tumor scores. In addition, when compared to free DOX, the DOX-PRNP2 reduced the angiogenic indicators VEGD and CD31 to a greater extent. Collectively, the findings demonstrated that formulating DOX in PRNPs was useful in enhancing antitumor activity and can be used in other models of cancers to verify their efficacy and compatibility with our study.

Role of PTEN, PI3K, and mTOR in Triple-Negative Breast Cancer

Breast cancer is the most commonly occurring malignancy and the leading cause of cancer-related death in women. Triple-negative breast cancer (TNBC) is the most aggressive subtype and is associated with high recurrence rates, high incidence of distant metastases, and poor overall survival. The aim of this study was to investigate the PI3K/PTEN/Akt/mTOR pathway as one of the most frequently deregulated pathways in cancer. We aimed to explore the impact of PI3K and mTOR oncogenes as well as the PTEN tumor suppressor on TNBC clinical behavior, prognosis, and multidrug resistance (MDR), using immunohistochemistry and copy number analysis by quantitative real-time PCR. Our results revealed that loss of PTEN and high expression of PI3K and mTOR proteins are associated with poor outcome of TNBC patients. PTEN deletions appeared as a major cause of reduced or absent PTEN expression in TNBC. Importantly, homozygous deletions of PTEN (and not hemizygous deletions) are a potential molecular marker of metastasis formation and good predictors of TNBC outcome. In conclusion, we believe that concurrent examination of PTEN/PI3K/mTOR protein expression may be more useful in predicting TNBC clinical course than the analysis of single protein expression. Specifically, our results showed that PTEN-reduced/PI3K-high/mTOR-high expression constitutes a ‘high risk’ profile of TNBC.

EnDuo, a novel derivative of Endostar, inhibits the migration of colon cancer cells, suppresses matrix metalloproteinase-2/9 expression and impedes AKT/ERK activation

BACKGROUND/AIMS

Colon cancer remains a life-threating disease with increasing morbidity and mortality worldwide despite the advancement in modern medical treatment. Therefore, novel and effective anti-colon cancers drugs are urgently needed. In this study, we investigated the anti-metastatic property EnDuo, a modified version of Endostar, and the underlying mechanisms.

METHODS

Colon cancer cells were treated with different concentrations of EnDuo (50 μg/mL, 100 μg/mL, 200 μg/mL), and Endostar (100 μg/mL) as positive control. Cell Counting Kit-8 assay was performed to test the effect of EnDuo on cell viability. A scratch wound assay and transwell assay were employed to evaluate the relocation and motility of malignant colon cells following treatment with EnDuo. Western blot analysis was used to determine inhibitory effects of EnDuo by detecting the phosphorylation level of AKT and ERK proteins, and the expression of MMP-2 and MMP-9 proteins.

RESULTS

Our results showed that EnDuo impedes the migration of colon cancer cells in a dose-dependent manner. At the molecular level, EnDuo induced a significant reduction in the phosphorylation of AKT and ERK proteins, and inhibited the expression of MMP-2 and MMP-9 proteins.

CONCLUSIONS

Collectively, these results demonstrate that EnDuo exhibits a comparable anti-metastatic effect by suppressing the migration of colon cancer cells. Possibly, EnDuo interrupts the PI3K/AKT/ERK signaling pathway to arrest cell migration. Our study provides a novel insight to the potential clinical applications of EnDuo against colon cancers in the future.

Anti-Angiogenic Effect of Asperchalasine A Via Attenuation of VEGF Signaling

Cytochalasans are a group of structurally diverse fungal polyketide-amino acid hybrid metabolites that exhibit diverse biological functions. Asperchalasine A was identified and isolated from an extract of the marine-derived fungus, Aspergillus. Asperchalasine A is a cytochalasan dimer which consists of two cytochalasan molecules connected by an epicoccine. This study investigated the potential antiangiogenic effects of Aspergillus extract and asperchalasine A, which significantly inhibited cell adhesion and tube formation in human umbilical vein endothelial cells (HUVECs). Aspergillus extract and asperchalasine A decreased the vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor (VEGFR)-2 mRNA expression in a concentration-dependent manner. In addition, Aspergillus extract and asperchalasine A inhibited angiogenesis via downregulation of VEGF, p-p38, p-extracellular signal-regulated protein kinase (ERK), p-VEGFR-2, and p-Akt signaling pathways. Moreover, Aspergillus extract and asperchalasine A significantly inhibited the amount of blood vessel formation in fertilized chicken eggs using a chorioallantoic membrane assay. Our results provide experimental evidence of this novel biological activity of the potential antiangiogenic substances, Aspergillus extract, and asperchalasine A. This study also suggests that Aspergillus extract and its active component asperchalasine A are excellent candidates as adjuvant therapeutic substances for cancer prevention and treatment.

Trans-vaccenic acid inhibits proliferation and induces apoptosis of human nasopharyngeal carcinoma cells via a mitochondrial-mediated apoptosis pathway

Background

Intake of trans fatty acids (TFAs) from partially hydrogenated vegetable oil is associated with a variety of adverse outcomes, but little is known about the health effects of ruminant trans fats. Trans-vaccenic acid (TVA) is a naturally occurring TFA found in the fat of ruminants and in human dairy products. The present study was conducted to investigate the anticancer activity and underlying mechanisms of TVA on human nasopharyngeal carcinoma (NPC) 5-8F and CNE-2 cells.

Methods

A CCK8 assay was used to determine the effect of TVA and the Mcl-1 inhibitor S63845 on the proliferation of NPC cells. Apoptosis was measured using flow cytometry. Western blotting was used to detect the protein expression levels of factors associated with Bcl-2-family protein signaling and Akt signaling.

Results

TVA significantly inhibited cell proliferation in a dose-dependent manner. Mechanistic investigation demonstrated that TVA significantly decreased p-Akt levels and Bad phosphorylation on Ser-136 and Ser-112. More importantly, we discovered that the Mcl-1 inhibitor S63845 synergistically sensitized NPC cells to apoptosis induction by TVA.

Conclusion

TVA can inhibit NPC cell growth and induced apoptosis through the inhibition of Bad/Akt phosphorylation. The combined use of TVA and Mcl-1 inhibitors offers a potential advantage for nasopharyngeal cancer treatment.

MicroRNA-29c inhibits proliferation and promotes apoptosis in non-small cell lung cancer cells by targeting VEGFA

Non-small cell lung cancer (NSCLC) is a primary sub-type of lung cancer with a high incidence rate and poor prognosis. The primary therapeutic treatment for NSCLC is chemotherapy, which is considered to be ineffective and excessively toxic. Novel therapeutic methods, particularly molecular targeted therapy, have attracted considerable attention. MicroRNAs (miRs) are reported to be potential biomarkers and targeted agents with roles in various types of tumors. Herein, the present study presented the observation of aberrant low expression of miR‑29c and associated overexpression of vascular endothelial growth factor A (VEGFA) in NSCLC tumor tissues. The effects of miR‑29c upon NSCLC tumor progression, including cell proliferation and cellular apoptosis, were investigated. The possible regulatory mechanism of action of miR‑29c on its direct target VEGFA and the phosphatidylinositol 3‑kinase (PI3K)/RAC‑α serine/threonine‑protein kinase (Akt) signaling pathway was examined using multiple methods, including reverse transcription-quantitative polymerase chain reaction analysis, dual luciferase assay and western blot analysis. The results demonstrated that miR‑29c expression was downregulated in NSCLC tumor tissues compared with normal tissues. A marked negative correlation in the expression of miR‑29c and VEGFA was observed in clinical NSCLC tissues and cultured NSCLC cells. Overexpression of miR‑29c may inhibit cell proliferation and accelerate the cellular apoptosis rate of NSCLC tumor cells. Furthermore, the overexpression of miR‑29c was demonstrated to be able to downregulate the expression levels of VEGFA and PI3K/Akt signaling pathway‑associated proteins. The results of the present study suggested that miR‑29c might regulate NSCLC tumor progression by targeting VEGFA.

Effects of thalidomide on growth and VEGF-A expression in SW480 colon cancer cells

Lymphatic and hematogenous spread are the most common ways for tumors to metastasize. Angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor (VEGF) particularly VEGF-A is important in the process of angiogenesis. The current research has indicated that thalidomide (THD) may be able to inhibit angiogenesis, stimulate the activity of the immune system and inhibit the adherence of cancer cells to stromal cells. These changes may lead to suppression of tumor occurrence and development. To date, to the best of our knowledge, the effects of THD on colon cancer SW480 cells have not been reported. In the present study, the effects of THD and a combination of THD and oxaliplatin (L-OHP) on the proliferation of SW480 cells have been investigated. Furthermore, the expression of VEGF-A and hypoxia-inducible factor 1 (HIF-1) was analyzed using MTT assay, quantitative polymerase chain reaction and western blot analysis. The results indicated that THD was able to inhibit SW480 cells in dose-and-time dependent manner and inhibit the expression of VEGF-A and HIF-1α. Furthermore, treatment with THD and L-OHP had synergistic inhibitory effect, which may provide a novel treatment strategy for advanced colorectal cancer.

Metformin synergistically enhances antitumor activity of cisplatin in gallbladder cancer via the PI3K/AKT/ERK pathway

Metformin (Met) is a widely used antidiabetic drug and has demonstrated interesting anticancer effects in various cancer models, alone or in combination with chemotherapeutic drugs. The aim of the present study is to investigate the synergistic effect of Met with cisplatin (Cis) on the tumor growth inhibition of gallbladder cancer cells (GBC-SD and SGC-996) and explore the underlying mechanism. Cells were treated with Met and/or Cis and subjected to cell viability, colony formation, apoptosis, cell cycle, western blotting, xenograft tumorigenicity assay and immunohistochemistry. The results demonstrated that Met and Cis inhibited the proliferation of gallbladder cancer cells, and combination treatment with Met and Cis resulted in a combination index < 1, indicating a synergistic effect. Co-treatment with Met and Cis caused G0/G1 phase arrest by upregulating P21, P27 and downregulating CyclinD1, and induced apoptosis through decreasing the expression of p-PI3K, p-AKT, and p-ERK. In addition, pretreatment with a specific AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of Met + Cis, suggesting the key role of AKT in this process. More importantly, in nude mice model, Met and Cis in combination displayed more efficient inhibition of tumor weight and volume in the SGC-996 xenograft mouse model than Met or Cis alone. Immunohistochemistry analysis suggests the combinations greatly suppressed tumor proliferation, which is consistent with our in vitro results. In conclusion, our findings indicate that the combination therapy with Met and Cis exerted synergistic antitumor effects in gallbladder cancer cells through PI3K/AKT/ERK pathway, and combination treatment with Met and Cis would be a promising therapeutic strategy for gallbladder cancer patients.

[Expression of cAMP-dependent protein kinase inhibitor beta in colorectal carcinoma and its clinical significance]

OBJECTIVE

To investigate the expression of cAMP-dependent protein kinase inhibitor beta (PKIB) in colorectal carcinoma (CRC) and its association with the clinicopathological factors of the patients.

METHODS

The expression of PKIB mRNA was detected with quantitative real-time PCR in 34 CRC tissues and paired adjacent tissues. Immunohistochemistry was used to detect the expression of PKIB protein in 72 CRC tissue specimens, and the relationship between PKIB protein expression and the clinicopathological features of the patients was analyzed.

RESULTS

The expression of PKIB mRNA was significantly higher in CRC tissues than in the paired asjacent tissues (P<0.0001). The expression of PKIB protein in CRC patients was closely related with tumor infiltration (T stage) (P=0.038) but not with age, gender, tumor size, location, lymph node metastasis (N stage) or distant metastasis (M stage) (P>0.05). The survival time of patients with high PKIB expressions was significantly shorter than that of patients with low PKIB expressions (70.532∓6.190 vs 93.500∓5.847 months, P=0.023).

CONCLUSION

A high expression of PKIB in CRC is positively correlated with tumor infiltration (T stage) and a poor prognosis, suggesting an important role of PKIB in the development of CRC and its value as an indicator for prognostic evaluation of CRC patients.

Odisolane, a Novel Oxolane Derivative, and Antiangiogenic Constituents from the Fruits of Mulberry (Morus alba L.)

Mulberry, the fruit of Morus alba L., is known as an edible fruit and commonly used in Chinese medicines as a warming agent and as a sedative, tonic, laxative, odontalgic, expectorant, anthelmintic, and emetic. Systemic investigation of the chemical constituents of M. alba fruits led to the identification of a novel oxolane derivative, (R*)-2-((2S*,3R*)-tetrahydro-2-hydroxy-2-methylfuran-3-yl)propanoic acid (1), namely, odisolane, along with five known heterocyclic compounds (2-6). The structure of the new compound was elucidated on the basis of HR-MS, 1D and 2D NMR ((1)H-(1)H COSY, HSQC, HMBC, and NOESY) data analysis. Compound 1 has a novel skeleton that consists of 8 carbon units with an oxolane ring, which until now has never been identified in natural products. The isolated compounds were subjected to several activity tests to verify their biological function. Among them, compounds 1, 3, and 5 significantly inhibited cord formation in HUVECs. The action mechanism of compound 3, which had the strongest antiangiogenic activity, was mediated by decreasing VEGF, p-Akt, and p-ERK protein expression. These results suggest that compounds isolated from M. alba fruits might be beneficial in antiangiogenesis therapy for cancer treatment.

Evaluation of tumor metastasis-associated markers for molecular classification in patients with esophageal squamous cell carcinoma

This study aims to ascertain the relationship of tumor metastasis-associated markers cyclin D1, connective tissue growth factor (CTGF) and vascular endothelial growth factor (VEGF) with the clinicopathologic features and prognosis of patients with esophageal squamous cell carcinoma (ESCC), and to investigate their value in ESCC molecular classification. The expression of cyclin D1, CTGF and VEGF in 100 specimens from patients and 20 from normal esophageal mucosa were detected by immunohistochemistry. The relationship of their expression with prognosis of the patients with ESCC was evaluated by Cox regression model and Kaplan-Meier survival curve analysis. High levels of expression of cyclin D1, CTGF, and VEGF were observed in 61 (61%), 53 (53%), 49 (49%) cases, respectively. Univariate survival analysis indicated that the levels of expression of cyclin D1, CTGF and VEGF were associated with survival (all P-value < 0.05). Multivariate analysis indicated that cyclin D1 and VEGF were independent prognostic factors affecting the three-year survival rate of patients (P = 0.001, 0.017, respectively). Furthermore, high level expression of cyclin D1, CTGF and VEGF in stage I patients was found associated with poor three-year survival rate (all P-value < 0.05). The prognosis probably was favorable for patients with low expression of cyclin D1 even in stage III, or VEGF even in stage IV. Tumor metastasis-associated markers such as cyclin D1 and VEGF may be independent prognostic factors affecting survival rate of postoperative ESCC patients. It is possible to judge prognosis better and tailor treatments to each individual patient when these markers were applied to ESCC molecular classification.

Correlation of extended RAS and PIK3CA gene mutation status with outcomes from the phase III AGITG MAX STUDY involving capecitabine alone or in combination with bevacizumab plus or minus mitomycin C in advanced colorectal cancer

BACKGROUND

Mutations affecting RAS genes are now established predictive markers of nonresponse to anti-EGFR antibodies in advanced CRC. This analysis assessed the prognostic and predictive impact of extended RAS and PIK3CA gene mutation status in patients receiving capecitabine plus or minus bevacizumab (±mitomycin C) in the randomised phase III MAX study.

METHODS

DNA was extracted from archival macrodissected formalin-fixed paraffin-embedded tumour tissue. Mutation status was determined using pyrosequencing, confirmed with Sanger sequencing (for equivocal RAS) and correlated with efficacy outcomes. Predictive analyses were undertaken using a test for interaction involving both C vs CB+CBM.

RESULTS

Of the available 280 of the 471 (59.4%) patients, mutations in KRAS exons 2, 3 and 4 and NRAS 2, 3 and 4 were as follows: 32%, 2.9%, 2.2%, 1.4%, 0.7% and 0% (total RAS MT 39%). The PIK3CA MT rate was 7.5% exon 9 and 3.6% exon 20. Extended RAS gene mutation status (WT vs MT) had no prognostic impact for PFS (HR 0.91 (0.71-1.17)) or OS (HR 0.95 (0.71-1.25)). The RAS gene mutation status was not predictive of the effectiveness of bevacizumab for PFS (HR 0.56 (0.37-0.85) for RAS MT and HR 0.69 (0.5-0.97) for RAS WT; P for interaction 0.50). The PIK3CA mutation was neither predictive for bevacizumab effect nor prognostic.

CONCLUSION

Of KRAS exon 2 WT patients, 10% had additional RAS mutations. Neither all RAS gene mutation status nor PIK3CA mutation status was prognostic for PFS or OS, or predictive of bevacizumab outcome in patients with advanced CRC.

Lupeol inhibits proliferation and induces apoptosis of human pancreatic cancer PCNA-1 cells through AKT/ERK pathways

Lupeol, a dietary triterpene, present in many fruits and medicinal plants, has been reported to possess many pharmacological properties including anti-cancer activities both in vitro and in vivo. However, the precise mechanism involved remains largely unknown. The present study is conducted to investigate the anti-cancer activity and the underlying mechanisms of lupeol on human pancreatic cancer proliferating cell nuclear antigen 1 (PCNA-1) cells in vitro and in vivo. Lupeol significantly inhibited the proliferation of the cells in dose- and time-dependent manners and induced apoptosis as well as cell cycle arrest in G0/G1 phase by upregulating P21 and P27 and downregulating cyclin D1. The expression of apoptosis-related proteins in cells was evaluated by western blot analysis, and we found that lupeol induced cell apoptosis by decreasing the levels of p-AKT and p-ERK. In addition, pretreatment with a specific PI3K/AKT activator (IGF-1) significantly neutralized the pro-apoptotic activity of lupeol in PCNA-1 cells, demonstrating the important role of AKT in this process. More importantly, our in vivo studies showed that administration of lupeol decreased tumor growth in a dose-dependent manner. Immunohistochemistry analysis demonstrated the downregulation of p-AKT and p-ERK in tumor tissues following lupeol treatment, consistent with the in vitro results. Therefore, these findings indicate that lupeol can inhibit cell proliferation and induce apoptosis as well as cell cycle arrest of PCNA-1 cells and might offer a therapeutic potential advantage for human pancreatic cancer chemoprevention or chemotherapy.

Vascular Endothelial Growth Factor in Colonic Cancer, Ulcerative Colitis and Colonic Adenoma: An Immunohistochemical Study

BACKGROUND: Colon cancer is one of the most common malignancies worldwide. Colonic adenoma and ulcerative colitis (UC) are important precancerous lesions. Vascular Endothelial Growth Factor (VEGF) is a well-known pro-angiogenic factor plays important role in physiologic and pathologic conditions and in neovascularization in cancer and hence becomes a potential target for anti-angiogenic cancer therapy.AIM: This study investigated VEGF immunohistochemical expression in colon cancer and its precancerous lesions. MATERIAL AND METHODS:  Paraffin blocks from two hospitals were collected in a year: Colon cancer: 20 cases, colonic adenoma: 15 cases, UC: 15 cases and 5 controls from normal mucosa. VEGF was assessed immunohistochemically using a primary anti-VEGF antibody (VG1, Dako, Denemark).RESULTS: Median age was 49 years (range 31-52) in cancer, 40 years (range 31-52) in adenomas and 33 years (range 27-43) in UC. VEGF expression was negative in control, significantly strongly positive in 90% of colonic adenocarcinoma (p= 0.001), significantly positive in adenomas (p= 0.002) - the weak positivity significantly seen in mild dysplasia (p= 0.001) - and significantly positive in 73.3% of UC cases (p=0.022).CONCLUSION: The significant increase in positivity of VEGF in precancerous to cancerous lesions may point to its potential role in the pathogenesis and progression of colonic neoplasia.

Inhibition of phosphoinositide 3-kinase/Akt pathway decreases hypoxia inducible factor-1α expression and increases therapeutic efficacy of paclitaxel in human hypoxic gastric cancer cells

The phosphatidylinositol-3-kinase (PI3K)/Akt signaling pathway plays an important role in cell proliferation, transformation, apoptosis, tumor growth and angiogenesis. Paclitaxel is commonly used to treat multiple human malignancies; however, the underlying mechanisms of paclitaxel in gastric cancer (GC) have not been fully investigated. In the present study, specimens from 45 GC and 36 chronic gastritis patients were collected, and the correlations of PI3K, phosphorylated-Akt (p-Akt) and hypoxia-inducible factor-1α (HIF-1α) expression with the clinicopathological characteristics of GC were analyzed by immunohistochemistry. The human SGC-7901 GC cells under hypoxic conditions were pretreated with the PI3K inhibitor, LY294002 (40 μM), and paclitaxel (0.1 μM). The expression levels of PI3K, p-Akt and HIF-1α were detected by quantitative polymerase chain reaction and western blotting. Cell proliferative activity and apoptosis were evaluated by the Cell Counting Kit-8 assay and flow cytometry. As a result, the rates of positive expression of PI3K, p-Akt and HIF-1α were significantly higher in GC compared with chronic gastritis patients (each P<0.01), and were positively associated with the tumor-node-metastasis (TNM) staging, lymph node metastases, lymphatic infiltration and vascular infiltration (each P<0.01), but inversely correlated with tumor differentiation (P<0.01) in patients with GC. Under hypoxic conditions, the combined inhibition of the PI3K/Akt pathway with paclitaxel markedly reduced the proliferative activity and induced cell apoptosis in GC cells compared with the single treatment of PI3K inhibitor or paclitaxel (each P<0.01), and was accompanied by a decreased expression of HIF-1α. Overall, our findings indicate that the increased expression of the PI3K/Akt/HIF-1α pathway was closely correlated with tumor differentiation, TNM staging, lymph node metastases and lymphatic and vascular infiltration. The inhibition of the PI3K/Akt pathway enhanced the therapeutic efficacy of paclitaxel in GC cells under hypoxic conditions, suggesting that the PI3K/Akt/HIF-1α pathway may act as an important therapeutic target for paclitaxel treatment of GC.

Matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway

The present study has investigated the anti-tumor activity and the underlying mechanisms of matrine on human colon cancer LoVo cells. Matrine inhibited the proliferation of the cells in dose- and time-dependent manners. The concentration required for 50 % inhibition (IC50) was 1.15, 0.738, and 0.414 mg/ml, when cell were incubated with matrine for 24, 48, and 72 h, respectively. Matrine induced cell cycle arrest at G1 phase by downregulating cyclin D1 and upregulating p27 and p21. Matrine induced cell apoptosis by reducing the ratio of Bcl-2/Bax and increasing the activation of caspase-9 in a dose-dependent manner. Matrine displayed its anti-tumor activity by inactivating Akt, the upstream factor of the above proteins. Matrine significantly reduced the protein levels of pAkt, and increased the protein levels of other downstream factors, pBad and pGSK-3β. Specific inhibition of pAkt induced cell apoptosis, and synergized with matrine to inhibit the proliferation of LoVo cells; whereas activation of Akt neutralized the inhibitory effect of matrine on cell proliferation. The present study has demonstrated that matrine inhibits proliferation and induces apoptosis of human colon cancer LoVo cells by inactivating Akt pathway, indicating matrine may be a potential anti-cancer agent for colon cancer.

Calcium deficiency-induced and TRP channel-regulated IGF1R-PI3K-Akt signaling regulates abnormal epithelial cell proliferation

Calcium deficiency causes abnormal colonic growth and increases colon cancer risk with poorly understood mechanisms. Here we elucidate a novel signaling mechanism underlying the Ca(2+) deficiency-induced epithelial proliferation using a unique animal model. The zebrafish larval yolk sac skin contains a group of Ca(2+)-transporting epithelial cells known as ionocytes. Their number and density increases dramatically when acclimated to low [Ca(2+)] environments. BrdU pulse-labeling experiments suggest that low [Ca(2+)] stimulates pre-existing ionocytes to re-enter the cell cycle. Low [Ca(2+)] treatment results in a robust and sustained activation of IGF1R-PI3K-Akt signaling in these cells exclusively. These ionocytes specifically express Igfbp5a, a high-affinity and specific binding protein for insulin-like growth factors (IGFs) and the Ca(2+)-selective channel Trpv5/6. Inhibition or knockdown of Igfbp5a, IGF1 receptor, PI3K, and Akt attenuates low [Ca(2+)]-induced ionocyte proliferation. The role of Trpv5/6 was investigated using a genetic mutant, targeted knockdown, and pharmacological inhibition. Loss-of-Trpv5/6 function or expression results in elevated pAkt levels and increased ionocyte proliferation under normal [Ca(2+)]. These increases are eliminated in the presence of an IGF1R inhibitor, suggesting that Trpv5/6 represses IGF1R-PI3K-Akt signaling under normal [Ca(2+)]. Intriguingly, blockade of Trpv5/6 activity inhibits the low [Ca(2+)]-induced activation of Akt. Mechanistic analyses reveal that the low [Ca(2+)]-induced IGF signaling is mediated through Trpv5/6-associated membrane depolarization. Low extracellular [Ca(2+)] results in a similar amplification of IGF-induced PI3K-PDK1-Akt signaling in human colon cancer cells in a TRPV6-dependent manner. These results uncover a novel and evolutionarily conserved signaling mechanism that contributes to the abnormal epithelial proliferation associated with Ca(2+) deficiency.

Aberrant, ectopic expression of VEGF and VEGF receptors 1 and 2 in malignant colonic epithelial cells. Implications for these cells growth via an autocrine mechanism

Vascular endothelial growth factor A (referred to as VEGF) is implicated in colon cancer growth. Currently, the main accepted mechanism by which VEGF promotes colon cancer growth is via the stimulation of angiogenesis, which was originally postulated by late Judah Folkman. However, the cellular source of VEGF in colon cancer tissue; and, the expression of VEGF and its receptors VEGF-R1 and VEGF-R2 in colon cancer cells are not fully known and are subjects of controversy.

MATERIAL AND METHODS

We examined and quantified expression of VEGF, VEGF-R1 and VEGF-R2 in three different human colonic tissue arrays containing sections of adenocarcinoma (n=43) and normal mucosa (n = 41). In human colon cancer cell lines HCT116 and HT29 and normal colon cell lines NCM356 and NCM460, we examined expression of VEGF, VEGF-R1 and VEGF-R2 mRNA and protein, VEGF production and secretion into the culture medium; and, the effect of a potent, selective inhibitor of VEGF receptors, AL-993, on cell proliferation.

RESULTS

Human colorectal cancer specimens had strong expression of VEGF in cancer cells and also expressed VEGF-R1 and VEGF-R2.In vitro studies showed that human colon cancer cell lines, HCT116 and HT29, but not normal colonic cell lines, express VEGF, VEGF-R1 and VEGF-R2 and secrete VEGF into the medium up to a concentration 2000 pg/ml within 48 h. Furthermore, we showed that inhibition of VEGF receptors using a specific VEGF-R inhibitor significantly reduced proliferation (by >50%) of cultured colon cancer cell lines.

CONCLUSIONS

Our findings support the contention that VEGF generated by colon cancer cells stimulates their growth directly through an autocrine mechanism that is independent of its primary function in the induction of angiogenesis.