Host immune peptides, including cathelicidins, have been reported to possess anticancer properties. We previously reported that LL-37, the only cathelicidin in humans, suppresses the development of ...colon cancer. In this study, the potential anticancer effect of FK-16, a fragment of LL-37 corresponding to residues 17 to 32, on cultured colon cancer cells was evaluated. FK-16 induced a unique pattern of cell death, marked by concurrent activation of caspase-independent apoptosis and autophagy. The former was mediated by the nuclear translocation of AIF and EndoG whereas the latter was characterized by enhanced expression of LC3-I/II, Atg5 and Atg7 and increased formation of LC3-positive autophagosomes. Knockdown of Atg5 or Atg7 attenuated the cytotoxicity of FK-16, indicating FK-16-induced autophagy was pro-death in nature. Mechanistically, FK-16 activated nuclear p53 to upregulate Bax and downregulate Bcl-2. Knockdown of p53, genetic ablation of Bax, or overexpression of Bcl-2 reversed FK-16-induced apoptosis and autophagy. Importantly, abolition of AIF/EndoG-dependent apoptosis enhanced FK-16-induced autophagy while abolition of autophagy augmented FK-16-induced AIF-/EndoG-dependent apoptosis. Collectively, FK-16 induces caspase-independent apoptosis and autophagy through the common p53-Bcl-2/Bax cascade in colon cancer cells. Our study also uncovered previously unknown reciprocal regulation between these two cell death pathways.
We aimed to characterise the microbial changes associated with histological stages of gastric tumourigenesis.
We performed 16S rRNA gene analysis of gastric mucosal samples from 81 cases including ...superficial gastritis (SG), atrophic gastritis (AG), intestinal metaplasia (IM) and gastric cancer (GC) from Xi'an, China, to determine mucosal microbiome dysbiosis across stages of GC. We validated the results in mucosal samples of 126 cases from Inner Mongolia, China.
We observed significant mucosa microbial dysbiosis in IM and GC subjects, with significant enrichment of 21 and depletion of 10 bacterial taxa in GC compared with SG (q<0.05). Microbial network analysis showed increasing correlation strengths among them with disease progression (p<0.001). Five GC-enriched bacterial taxa whose species identifications correspond to
,
,
,
and
had significant centralities in the GC ecological network (p<0.05) and classified GC from SG with an area under the receiver-operating curve (AUC) of 0.82. Moreover, stronger interactions among gastric microbes were observed in
-negative samples compared with
-positive samples in SG and IM. The fold changes of selected bacteria, and strengths of their interactions were successfully validated in the Inner Mongolian cohort, in which the five bacterial markers distinguished GC from SG with an AUC of 0.81.
In addition to microbial compositional changes, we identified differences in bacterial interactions across stages of gastric carcinogenesis. The significant enrichments and network centralities suggest potentially important roles of
,
,
,
and
in GC progression.
It is uncertain whether aspirin therapy should be continued after endoscopic hemostatic therapy in patients who develop peptic ulcer bleeding while receiving low-dose aspirin.
To test that continuing ...aspirin therapy with proton-pump inhibitors after endoscopic control of ulcer bleeding was not inferior to stopping aspirin therapy, in terms of recurrent ulcer bleeding in adults with cardiovascular or cerebrovascular diseases.
A parallel randomized, placebo-controlled noninferiority trial, in which both patients and clinicians were blinded to treatment assignment, was conducted from 2003 to 2006 by using computer-generated numbers in concealed envelopes. (ClinicalTrials.gov registration number: NCT00153725)
A tertiary endoscopy center.
Low-dose aspirin recipients with peptic ulcer bleeding.
78 patients received aspirin, 80 mg/d, and 78 received placebo for 8 weeks immediately after endoscopic therapy. All patients received a 72-hour infusion of pantoprazole followed by oral pantoprazole. All patients completed follow-up.
The primary end point was recurrent ulcer bleeding within 30 days confirmed by endoscopy. Secondary end points were all-cause and specific-cause mortality in 8 weeks.
156 patients were included in an intention-to-treat analysis. Three patients withdrew from the trial before finishing follow-up. Recurrent ulcer bleeding within 30 days was 10.3% in the aspirin group and 5.4% in the placebo group (difference, 4.9 percentage points 95% CI, -3.6 to 13.4 percentage points). Patients who received aspirin had lower all-cause mortality rates than patients who received placebo (1.3% vs. 12.9%; difference, 11.6 percentage points CI, 3.7 to 19.5 percentage points). Patients in the aspirin group had lower mortality rates attributable to cardiovascular, cerebrovascular, or gastrointestinal complications than patients in the placebo group (1.3% vs. 10.3%; difference, 9 percentage points CI, 1.7 to 16.3 percentage points).
The sample size is relatively small, and only low-dose aspirin, 80 mg, was used. Two patients with recurrent bleeding in the placebo group did not have further endoscopy.
Among low-dose aspirin recipients who had peptic ulcer bleeding, continuous aspirin therapy may increase the risk for recurrent bleeding but potentially reduces mortality rates. Larger trials are needed to confirm these findings.
Alterations of gut microbiota are associated with colorectal cancer (CRC) in different populations and several bacterial species were found to contribute to the tumorigenesis. The potential use of ...gut microbes as markers for early diagnosis has also been reported. However, cohort specific noises may distort the structure of microbial dysbiosis in CRC and lead to inconsistent results among studies. In this regard, our study targeted at exploring changes in gut microbiota that are universal across populations at species level.
Based on the combined analysis of 526 metagenomic samples from Chinese, Austrian, American, and German and French cohorts, seven CRC-enriched bacteria (Bacteroides fragilis, Fusobacterium nucleatum, Porphyromonas asaccharolytica, Parvimonas micra, Prevotella intermedia, Alistipes finegoldii, and Thermanaerovibrio acidaminovorans) have been identified across populations. The seven enriched bacterial markers classified cases from controls with an area under the receiver-operating characteristics curve (AUC) of 0.80 across the different populations. Abundance correlation analysis demonstrated that CRC-enriched and CRC-depleted bacteria respectively formed their own mutualistic networks, in which the latter was disjointed in CRC. The CRC-enriched bacteria have been found to be correlated with lipopolysaccharide and energy biosynthetic pathways.
Our study identified potential diagnostic bacterial markers that are robust across populations, indicating their potential universal use for non-invasive CRC diagnosis. We also elucidated the ecological networks and functional capacities of CRC-associated microbiota.
We have previously demonstrated that peroxisome proliferator-activated receptor (PPARγ) activation inhibits hepatocarcinogenesis. We aim to investigate the effect of PPARγ on hepatocellular carcinoma ...(HCC) metastatic potential and explore its underlying mechanisms.
Human HCC cells (MHCC97L, BEL-7404) were infected with adenovirus-expressing PPARγ (Ad-PPARγ) or Ad-lacZ and treated with or without PPARγ agonist (rosiglitazone). The effects of PPARγ on cell migration and invasive activity were determined by wound healing assay and Matrigel invasive model in vitro, and in an orthotopic liver tumour metastatic model in mice.
Pronounced expression of PPARγ was demonstrated in HCC cells (MHCC97L, BEL-7404) treated with Ad-PPARγ, rosiglitazone or Ad-PPARγ plus rosiglitazone, compared with control (Ad-LacZ). Such induction markedly suppressed HCC cell migration. Moreover, the invasiveness of MHCC97L and BEL-7404 cells infected with Ad-PPARγ, or treated with rosiglitazone was significantly diminished up to 60%. Combination of Ad-PPARγ and rosiglitazone showed an additive effect. Activation of PPARγ by rosiglitazone significantly reduced the incidence and severity of lung metastasis in an orthotopic HCC mouse model. Key mechanisms underlying the effect of PPARγ in HCC include upregulation of cell adhesion genes, E-cadherin and SYK (spleen tyrosine kinase), extracellular matrix regulator tissue inhibitors of metalloproteinase (TIMP) 3, tumour suppressor gene retinoblastoma 1, and downregulation of pro-metastatic genes MMP9 (matrix metallopeptidase 9), MMP13, HPSE (heparanase), and Hepatocyte growth factor (HGF). Direct transcriptional regulation of TIMP3, MMP9, MMP13, and HPSE by PPARγ was shown by ChIP-PCR.
Peroxisome proliferator-activated receptor-gamma exerts an inhibitory effect on the invasive and metastatic potential of HCC in vitro and in vivo, and is thus, a target for the prevention and treatment of HCC metastases.
The pathogenesis of UC relates to gut microbiota dysbiosis. We postulate that alterations in the viral community populating the intestinal mucosa play an important role in UC pathogenesis. This study ...aims to characterise the mucosal virome and their functions in health and UC.
Deep metagenomics sequencing of virus-like particle preparations and bacterial 16S rRNA sequencing were performed on the rectal mucosa of 167 subjects from three different geographical regions in China (UC=91; healthy controls=76). Virome and bacteriome alterations in UC mucosa were assessed and correlated with patient metadata. We applied partition around medoids clustering algorithm and classified mucosa viral communities into two clusters, referred to as mucosal virome metacommunities 1 and 2.
In UC, there was an expansion of mucosa viruses, particularly
bacteriophages, and a decrease in mucosa
diversity, richness and evenness compared with healthy controls. Altered mucosal virome correlated with intestinal inflammation. Interindividual dissimilarity between mucosal viromes was higher in UC than controls.
and
were more abundant in the mucosa of UC than controls. Compared with metacommunity 1, metacommunity 2 was predominated by UC subjects and displayed a significant loss of various viral species. Patients with UC showed substantial abrogation of diverse viral functions, whereas multiple viral functions, particularly functions of bacteriophages associated with host bacteria fitness and pathogenicity, were markedly enriched in UC mucosa. Intensive transkingdom correlations between mucosa viruses and bacteria were significantly depleted in UC.
We demonstrated for the first time that UC is characterised by substantial alterations of the mucosa virobiota with functional distortion. Enrichment of
bacteriophages, increased phage/bacteria virulence functions and loss of viral-bacterial correlations in the UC mucosa highlight that mucosal virome may play an important role in UC pathogenesis.
Autophagy, hallmarked by the formation of double-membrane bound organelles known as autophagosomes, is a lysosome-dependent pathway for protein degradation. The role of autophagy in carcinogenesis is ...context dependent. As a tumor-suppressing mechanism in early-stage carcinogenesis, autophagy inhibits inflammation and promotes genomic stability. Moreover, disruption of autophagy-related genes accelerates tumorigenesis in animals. However, autophagy may also act as a pro-survival mechanism to protect cancer cells from various forms of cellular stress. In cancer therapy, adaptive autophagy in cancer cells sustains tumor growth and survival in face of the toxicity of cancer therapy. To this end, inhibition of autophagy may sensitize cancer cells to chemotherapeutic agents and ionizing radiation. Nevertheless, in certain circumstances, autophagy mediates the therapeutic effects of some anticancer agents. Data from recent studies are beginning to unveil the apparently paradoxical nature of autophagy as a cell-fate decision machinery. Taken together, modulation of autophagy is a novel approach for enhancing the efficacy of existing cancer therapy, but its Janus-faced nature may complicate the clinical development of autophagy modulators as anticancer therapeutics.
MicroRNAs (miRNAs) are 19-25-nucleotides regulatory non-protein-coding RNA molecules that regulate the expressions of a wide variety of genes, including some involved in cancer development. In this ...study, we investigated the possible role of miR-143 in colorectal cancer (CRC).
Expression levels of human mature miRNAs were examined using real-time PCR-based expression arrays on paired colorectal carcinomas and adjacent non-cancerous colonic tissues. The downregulation of miR-143 was further evaluated in colon cancer cell lines and in paired CRC and adjacent non-cancerous colonic tissues by qRT-PCR. Potential targets of miR-143 were defined. The functional effect of miR-143 and its targets was investigated in human colon cancer cell lines to confirm miRNA-target association.
Both real-time PCR-based expression arrays and qRT-PCR showed that miR-143 was frequently downregulated in 87.5% (35 of 40) of colorectal carcinoma tissues compared with their adjacent non-cancerous colonic tissues. Using in silico predictions, DNA methyltranferase 3A (DNMT3A) was defined as a potential target of miR-143. Restoration of the miR-143 expression in colon cell lines decreased tumour cell growth and soft-agar colony formation, and downregulated the DNMT3A expression in both mRNA and protein levels. DNMT3A was shown to be a direct target of miR-143 by luciferase reporter assay. Furthermore, the miR-143 expression was observed to be inversely correlated with DNMT3A mRNA and protein expression in CRC tissues.
Our findings suggest that miR-143 regulates DNMT3A in CRC. These findings elucidated a tumour-suppressive role of miR-143 in the epigenetic aberration of CRC, providing a potential development of miRNA-based targeted approaches for CRC therapy.
Recent researches have shed light on the biological importance of microRNAs (miRNAs) in colorectal cancer (CRC) genesis, progression and response to treatments. The potential utility of miRNAs in the ...preclinical stage have been explored and investigated. In this review, we explored the literature and reviewed the cutting edge progress in the discovery of noninvasive plasma and faecal miRNAs for CRC early diagnosis, as well as their measurability and predictability. We also discussed the utility of miRNAs as novel prognostic and predictive markers, and their association with CRC clinical phenotypes including recurrence, metastasis and therapeutic outcomes. Finally, we summarised miRNA-related single-nucleotide polymorphisms and their potential influence on sporadic CRC susceptibility and therapeutic response. In conclusion, the use of miRNAs as biomarker for CRC is still in its infancy and need further characterisation and evaluation.
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