Lauric acid can improve the sensitization of Cetuximab in KRAS/BRAF mutated colorectal cancer cells by retrievable microRNA-378 expression

Novel insights on perils and promises of miRNA in understanding colon cancer metastasis and progression

Colorectal cancer (CRC) is the third highest frequent malignancy and ultimate critical source of cancer-associated mortality around the world. Regardless of latest advances in molecular and surgical targeted medicines that have increased remedial effects in CRC patients, the 5-year mortality rate for CRC patients remains dismally low. Evidence suggests that microRNAs (miRNAs) execute an essential part in the development and spread of CRC. The miRNAs are a type of short non-coding RNA that exhibited to control the appearance of tumor suppressor genes and oncogenes. miRNA expression profiling is already being utilized in clinical practice as analytical and prognostic biomarkers to evaluate cancer patients' tumor genesis, advancement, and counteraction to drugs. By modulating their target genes, dysregulated miRNAs are linked to malignant characteristics (e.g., improved proliferative and invasive capabilities, cell cycle aberration, evasion of apoptosis, and promotion of angiogenesis). This review presents an updated summary of circulatory miRNAs, tumor-suppressive and oncogenic miRNAs, and the potential reasons for dysregulated miRNAs in CRC. Further we will explore the critical role of miRNAs in CRC drug resistance.

Lauric Acid Overcomes Hypoxia-Induced Gemcitabine Chemoresistance in Pancreatic Ductal Adenocarcinoma

Although gemcitabine (GEM) is widely used in chemotherapy for pancreatic ductal adenocarcinoma (PDA), drug resistance restricts its clinical effectiveness. To examine the mechanism of GEM resistance, we established two GEM-resistant cell lines from human PDA cells by continuous treatment with GEM and CoCl₂-induced chemical hypoxia. One resistant cell line possessed reduced energy production and decreased mitochondrial reactive oxygen species levels, while the other resistant cell line possessed increased stemness. In both cell lines, ethidium bromide-stained mitochondrial DNA levels decreased, suggesting mitochondrial DNA damage. Inhibition of hypoxia-inducible factor-1α in both cell lines did not restore the GEM sensitivity. In contrast, treatment of both cell types with lauric acid (LAA), a medium-chain fatty acid, restored GEM sensitivity. These results suggest that decreased energy production, decreased mitochondrial reactive oxygen species levels, and increased stemness associated with mitochondrial damage caused by GEM lead to GEM resistance, and that hypoxia may promote this process. Furthermore, forced activation of oxidative phosphorylation by LAA could be a tool to overcome GEM resistance. Clinical verification of the effectiveness of LAA in GEM resistance is necessary in the future.

Depicting the Implication of miR-378a in Cancers

MicroRNA-378a (miR-378a), including miR-378a-3p and miR-378a-5p, are encoded in PPARGC1B gene. miR-378a is essential for tumorigenesis and is an independent prognostic biomarker for various malignant tumors. Aberrant expression of miR-378a affects several physiological and pathological processes, including proliferation, apoptosis, tumorigenesis, cancer invasion, metastasis, and therapeutic resistance. Interestingly, miR-378a has a dual functional role in either promoting or inhibiting tumorigenesis, independent of the cancer type. In this review, we comprehensively summarized the role and regulatory mechanisms of miR-378a in cancer development, hoping to provide a direction for its potential use in cancer therapy.

Promotion or remission: a role of noncoding RNAs in colorectal cancer resistance to anti-EGFR therapy

Anti-epidermal-growth-factor-receptor (EGFR) monoclonal antibodies (mAbs) are of great significance for RAS and BRAF wild-type metastatic colorectal cancer (mCRC) patients. However, the generation of primary and secondary resistance to anti-EGFR mAbs has become an important factor restricting its efficacy. Recent studies have revealed that non-coding RNAs (ncRNAs), especially long non-coding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs), are implicated in anti-EGFR antibodies resistance, affecting the sensitivity of CRC cells to Cetuximab and Panitumumab. This paper briefly reviewed the research advance of the expression, signaling network and functional mechanism of ncRNAs related to anti-EGFR mAbs resistance in CRC, as well as their relationship with clinical prognosis and the possibility of therapeutic targets. In addition, some ncRNAs that are involved in the regulation of signaling pathways or genes related to anti-EGFR resistance, but need to be further verified by resistance experiments were also included in this review, thereby providing more ideas and basis for ncRNAs as CRC prognostic markers and anti-EGFR therapy sensitizers. Video Abstract.

The role of miR-370 and miR-138 in the regulation of BMP2 suppressor gene expression in colorectal cancer: preliminary studies

PURPOSE

Colorectal cancer (CRC) is the fourth-most common cancer worldwide and the second most common cancer cause of death in the world. The components of the TGFβ-signalling pathway, which are often affected by miRNAs, are involved in the regulation of apoptosis and cell cycle. Therefore, in the current study, the expression of BMP2 gene in CRC tissues at different clinical stages compared to the non-tumour tissues has been assessed. Moreover, the plasma BMP2 protein concentration in the same group of CRC patients has been validated. Due to the constant necessity to conduct further research of the correlation between specific miRNAs and mRNAs in CRC, in silico analysis has been performed to select miRNAs that regulate BMP2 mRNA.

METHODS

The cDNA samples from tumor and non-tumor tissue were used in a qPCR reaction to determine the mRNA expression of the BMP2 gene and the expression of selected miRNAs. The concentration of BMP2 protein in plasma samples was also measured.

RESULTS

It was indicated that BMP2 was downregulated in CRC tissue. Moreover, miR-370 and miR-138 expression showed an upward trend. Decreased BMP2 with accompanied increasing miR-370 and miR-138 expression was relevant to the malignant clinicopathological features of CRC and consequently poor patient prognosis.

CONCLUSION

Our data suggest that miR-370 with its clear expression in plasma samples may be a potential diagnostic marker to determine the severity of the disease in patients at a later stage of colorectal cancer.

Non-Coding RNAs Regulate the Resistance to Anti-EGFR Therapy in Colorectal Cancer

Colorectal cancer (CRC) is the third prevalent cancer worldwide, the morbidity and mortality of which have been increasing in recent years. As molecular targeting agents, anti-epidermal growth factor receptor (EGFR) monoclonal antibodies (McAbs) have significantly increased the progression-free survival (PFS) and overall survival (OS) of metastatic CRC (mCRC) patients. Nevertheless, most patients are eventually resistant to anti-EGFR McAbs. With the intensive study of the mechanism of anti-EGFR drug resistance, a variety of biomarkers and pathways have been found to participate in CRC resistance to anti-EGFR therapy. More and more studies have implicated non-coding RNAs (ncRNAs) primarily including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are widely involved in tumorigenesis and tumor progression. They function as essential regulators controlling the expression and function of oncogenes. Increasing data have shown ncRNAs affect the resistance of molecular targeted drugs in CRC including anti-EGFR McAbs. In this paper, we have reviewed the advance in mechanisms of ncRNAs in regulating anti-EGFR McAbs therapy resistance in CRC. It provides insight into exploring ncRNAs as new molecular targets and prognostic markers for CRC.

USP19 exacerbates lipogenesis and colorectal carcinogenesis by stabilizing ME1

Lipogenesis plays a critical role in colorectal carcinogenesis, but precisely how remains unclear. Here, we show that ERK2 phosphorylates ME1 at T103, thereby inhibiting its polyubiquitination and proteasomal degradation and enhancing its interaction with USP19. USP19 antagonizes RNF1-mediated ME1 degradation by deubiquitination, which in turn promotes lipid metabolism and NADPH production and suppresses ROS. Meanwhile, ROS dramatically increases PD-L1 mRNA levels through accelerating expression of the transcription factor NRF2. Increased lipid metabolism is correlated with ERK2 activity and colorectal carcinogenesis in human patients. Therefore, the combination of ERK2 inhibitor and anti-PD-L1 antibody significantly inhibits spontaneous and chemically induced colorectal carcinogenesis. Collectively, the USP19-ME1 axis plays a vital role in colorectal carcinogenesis and may also provide a potential therapeutic target.

Data Mining, Network Pharmacology, and Molecular Docking Explore the Effects of Core Traditional Chinese Medicine Prescriptions in Patients with Rectal Cancer and Qi and Blood Deficiency Syndrome

Background

“Zheng” (syndrome) is the basic unit and the basis of traditional Chinese medicine (TCM) treatment. In clinical practice, we have been able to improve the survival time and quality of life for patients with rectal cancer through the treatment of “FuZhengXiaoJi” (strengthening the Qi and reducing accumulation).

Purpose

In this study, we elucidated the core prescriptions for patients with rectal cancer and Qi and blood deficiency syndrome, and we explored the potential mechanisms of the prescriptions using an integrated strategy that coupled data mining with network pharmacology.

Methods

A Bron–Kerbosch (BK) algorithm was applied to find the core prescriptions. The active ingredients, targets, activated signaling pathways, and biological functions of core prescriptions were analyzed using network pharmacology and directly associated proteins were docked using molecular docking technology to elucidate the multicomponent, multitarget, and inter-related components associated with TCM systematically.

Results

Data mining identified 3 core prescriptions, and most of the herbs consisted of “FuZhengXiaoJi” Fang. Network pharmacology identified 15 high-degree active ingredients among the 3 core prescriptions and 16 high-degree hub genes linked with both rectal cancer and the 3 core prescriptions. Additional Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses of these 16 targets showed that the most significant pathways were MAPK, interleukin-17, tumor necrosis factor (TNF), and vascular endothelial growth factor (VEGF) pathways. From the 16 genes, TGFB1, IL1B, IL10, IL6, PTGS2, and PPARG closely interacted with the tumor microenvironment, and PPARG, MYC, and ERBB2 were closely linked to survival. In molecular docking, quercetin, kaempferol, and lauric acid showed good binding energy to each target.

Conclusion

Data mining, network pharmacology, and molecular docking may help identify core prescriptions, high-degree ingredients, and high-degree hub genes to apply to diseases and treatments. Furthermore, these studies may help discover hub genes that affect the tumor microenvironment and survival. The combination of these tools may help elucidate the relationship between herbs acting on “Zheng” (syndrome) and diseases, thus expanding the understanding of TCM mechanisms.

MicroRNA‑378d inhibits Glut4 by targeting Rsbn1 in vitamin D deficient ovarian granulosa cells

Vitamin D (VD) is not only associated with bone growth and development, but is also closely associated with numerous other pathological conditions. The present study aimed to investigate the effect of microRNA (miRNA/miR)-378d on ovarian granulosa cells by regulating the round spermatid basic protein 1 (Rsbn1) in the absence of VD. The abnormal expression of miRNAs in ovarian tissues of the VD-deficient mouse was analyzed using transcriptome sequencing. miR-378d, glucose transporter 4 (Glut4) and aromatase (Cyp19a) expression levels were examined via reverse transcription-quantitative (RT-q)PCR and western blotting. The expression levels of Rsbn1, Glut4 and Cyp19a were detected in transfected mouse ovarian granulosa cells. The targeting regulation between miR-378d and Rsbn1 was verified using double reporter gene assay and functional rescue experiments. Among the 672 miRNAs that were differentially expressed, cluster analysis revealed that 17 were significantly upregulated and 16 were significantly downregulated. Moreover, miR-378d showed significant upregulation, which was further verified via RT-qPCR. It was identified that the protein expression level of Rsbn1 was significantly downregulated. Furthermore, Glut4 mRNA expression was significantly decreased in the mimic group but markedly increased in the inhibitor group. By contrast, the mRNA expression levels of Rsbn1 and Cyp19a did not demonstrate any significant difference. The western blotting results indicated that the protein expression levels of Rsbn1 and Glut4 were decreased and increased, respectively, while Cyp19a did not show any significant change. In addition, the double reporter gene experiments confirmed that Rsbn1 was the target gene of miR-378d. Collectively, the present results demonstrated that miR-378d was abnormally overexpressed in the ovarian tissues of the VD-deficient mice, and that miR-378d could inhibit Glut4 production by targeting Rsbn1, which may lead to insulin resistance.

Preparation of a novel EGFR specific immunotoxin and its efficacy of anti-colorectal cancer in vitro and in vivo

OBJECTIVES

Epithelial growth factor receptor (EGFR), as a malignancy marker, is overly expressed in multiple solid tumors including colorectal neoplasms, one of the most prevalent malignancies worldwide. The main objective of this study is to enhance the efficacy of anti-tumor therapy targeting EGFR by constructing a novel EGFR-specific immunotoxin (C-CUS_245C) based on Cetuximab and recombinant Cucurmosin (CUS_245C).

METHODS

E. coli BL21 (DE3) PlysS (E. coli) was used to express CUS_245C with a cysteine residue inserting to the C-terminus of Cucurmosin. Then immobilized metal ion affinity chromatography (IMAC) was used to purify CUS_245C. The chemical conjugation method was used for the preparation of C-CUS_245C. Then dialysis and IMAC were used to purify C-CUS_245C. Western blot as well as SDS-PAGE was carried out to characterize the formation of C-CUS_245C. At last the anti-colorectal cancer activity of C-CUS_245C was investigated in vitro and in vivo.

RESULTS

CUS_245C with high purity could be obtained from the prokaryotic system. C-CUS_245C was successfully constructed and highly purified. The cytotoxicity assays in vitro showed a significant proliferation inhibition of C-CUS_245C on EGFR-positive cells for 120 h with IC₅₀ values less than 0.1 pM. Besides, the anti-tumor efficacy of C-CUS_245C was remarkably more potent than that of Cetuximab, CUS_245C, and C + CUS_245C (P < 0.001). Whereas the cytotoxicity of C-CUS_245C could hardly be detected on EGFR-null cell line. Our results also showed that C-CUS_245C had efficacy of anti-colorectal cancer in mouse xenograft model, indicating the therapeutic potential of C-CUS_245C for the targeted therapy of colorectal neoplasms.

CONCLUSIONS

C-CUS_245C exhibits potent and EGFR-specific cytotoxicity. Insertional mutagenesis technique is worthy to be adopted in the preparation of immunotoxin. Immunotoxin can be highly purified through dialysis followed by IMAC.

Dietary Fat and Cancer-Which Is Good, Which Is Bad, and the Body of Evidence

A high-fat diet (HFD) induces changes in gut microbiota leading to activation of pro-inflammatory pathways, and obesity, as a consequence of overnutrition, exacerbates inflammation, a known risk factor not only for cancer. However, experimental data showed that the composition of dietary fat has a greater impact on the pathogenesis of cancer than the total fat content in isocaloric diets. Similarly, human studies did not prove that a decrease in total fat intake is an effective strategy to combat cancer. Saturated fat has long been considered as harmful, but the current consensus is that moderate intake of saturated fatty acids (SFAs), including palmitic acid (PA), does not pose a health risk within a balanced diet. In regard to monounsaturated fat, plant sources are recommended. The consumption of plant monounsaturated fatty acids (MUFAs), particularly from olive oil, has been associated with lower cancer risk. Similarly, the replacement of animal MUFAs with plant MUFAs decreased cancer mortality. The impact of polyunsaturated fatty acids (PUFAs) on cancer risk depends on the ratio between ω-6 and ω-3 PUFAs. In vivo data showed stimulatory effects of ω-6 PUFAs on tumour growth while ω-3 PUFAs were protective, but the results of human studies were not as promising as indicated in preclinical reports. As for trans FAs (TFAs), experimental data mostly showed opposite effects of industrially produced and natural TFAs, with the latter being protective against cancer progression, but human data are mixed, and no clear conclusion can be made. Further studies are warranted to establish the role of FAs in the control of cell growth in order to find an effective strategy for cancer prevention/treatment.

Lauric Acid Modulates Cancer-Associated microRNA Expression and Inhibits the Growth of the Cancer Cell

BACKGROUND

microRNAs are known to regulate various protein-coding gene expression posttranscriptionally. Fatty acids are cell membrane constituents and are also known to influence the biological activities of the cells like signal transduction, growth and differentiation of the cells, apoptosis induction, and other physiological functions. In our experiments, we used lauric acid to analyse its effects on human cancerous cell lines.

OBJECTIVE

Our objective was to speculate the miRNA expression profile in lauric acid treated and untreated cancerous cell lines and further study the metabolic pathways of the targeted tumour suppressor and oncogenes.

METHODS

The KB cells and HepG2 cells were treated with lauric acid and miRNA was isolated and the expression of tumour suppressor and oncogenic miRNA was measured by quantitative PCR. The untreated cells were used as control. The metabolic pathways of the target tumour suppressor and oncogenes were examined by GeneMANIA software.

RESULTS

Interestingly, the lauric acid treatment suppresses the expression of oncogenic miRNA and significantly upregulated the expression of some tumour suppressor miRNAs. GeneMANIA metabolic pathway revealed that the upregulated tumour suppressor miRNAs regulate several cancer-associated pathways such as DNA damage, signal transduction p53 class mediator, stem cell differentiation, cell growth, cell cycle phase transition, apoptotic signalling pathway, cellular response to stress and radiation, etc. whereas oncogenic miRNAs regulate the cancer-associated pathway like cell cycle phase transition, apoptotic signalling pathway, cell growth, response to oxidative stress, immune response activating cell surface protein signalling pathway, cyclin-dependent protein kinase activity, epidermal growth factor receptor signalling pathways, etc. Conclusion: In our study, we found that lauric acid works as an anticancer agent by altering the expression of miRNAs.

The potential role of regulatory microRNAs of RAS/MAPK signaling pathway in the pathogenesis of colorectal cancer

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. Dysregulation of RAS/MAPK signaling axis is frequently found in CRC patients. The RAS/MAPK axis regulates cancer cell proliferation, apoptosis, inflammation, migration, and metastasis. Oncogenic or tumor-suppressor microRNAs (miRNAs) for RAS/MAPK signaling play a key role in the pathogenesis of CRC and are considered as novel potential biomarkers for diagnosis and prognosis of human malignancies. This review summarizes the current knowledge of mechanisms of action of RAS/MAPK miRNAs in the development and progression of CRC for a better understanding and hence a better management of this disease.

Roles of microRNAs as non-invasive biomarker and therapeutic target in colorectal cancer

MicroRNAs are endogenous, short non-coding RNA molecules that function as critical regulators of various biological processes. There is a strong functional evidence linking the involvement of dysregulated miRNAs to the occurrence, development and progression of colorectal cancer. Studies indicate that while overexpression of oncomiRs, and repression of tumor suppressor miRNAs tends to drive the overall tumorigenic process, the global picture of aberrant miRNA expression in colorectal cancer can classify the disease into multiple molecular phenotypes. Moreover, the expression pattern of miRNAs in colorectal cancer make them viable disease determinants as well as potential therapeutic targets. Through this review, we will summarize the importance of miRNAs in the etiology and progression of colorectal cancer. Specifically, we will explore the key role played by these RNA molecules as likely therapeutic avenues and the strategies presently available to target them. Finally, we will investigate the role of miRNAs as potential non-invasive diagnostic and prognostic biomarkers in colorectal cancer.

EPA significantly improves anti-EGFR targeted therapy by regulating miR-378 expression in colorectal cancer

It is known that colorectal cancer (CRC) cells containing mutations of the genes KRAS and BRAF are predominate mechanisms causing resistance to epidermal growth factor receptor (EGFR) inhibitors, and commonly exhibit a lower expression of microRNA-378 (miR-378) when compared with the wild type. In the present study, the aim was to determine the possible mechanism which associates miR-378 with the mitogen-activated protein kinase pathway, and to determine the efficiency of eicosapentaenoic acid ethyl ester (EPA) in its ability to restore sensitivity towards cetuximab, an EGFR inhibitor. The results demonstrated that a combined treatment of 40 µM EPA with 0.2 µM cetuximab can significantly suppress the cell growth in KRAS-mutant and control wild-type cells. Furthermore, the higher phosphorylated protein level of extracellular-signal-regulated kinase 1/2 was notable in KRAS EPA-treated cells (P=0.006-0.047) and resulted in significantly increased cell death; however, inconsistent results were indicated in EPA-treated BRAF-mutant cells, compared with the original cells (without treatment). KRAS-mutant and wild-type Caco-2 cells treated with EPA exhibited increased cetuximab response rates, but these response rates were reduced in the BRAF-mutant cells. In conclusion, upregulation of miR-378 induced by EPA may result in the significant restoration of sensitivity to cetuximab in the KRAS-mutant cells. The present data will contribute to a notable potential therapeutic solution for future clinical CRC treatments.

MicroRNAs in cancer drug resistance: Basic evidence and clinical applications

Development of drug resistance has considerably limited the efficacy of cancer treatments, including chemotherapy and targeted therapies. Hence, understanding the molecular mechanisms underpinning the innate or the acquired resistance to these therapies is critical to improve drug efficiency and clinical outcomes. Several studies have implicated microRNAs (miRNA) in this process. MiRNAs repress gene expression by specific binding to complementary sequences in the 3' region of target messenger RNAs (mRNAs), followed by target mRNA degradation or blocked translation. By targeting molecules specific to a particular pathway within tumor cells, the new generation of cancer treatment strategies has shown significant advantages over conventional chemotherapy. However, the long-term efficacy of targeted therapies often remains poor, because tumor cells develop resistance to such therapeutics. Targeted therapies often involve monoclonal antibodies (mAbs), such as those blocking the ErB/HER tyrosine kinases, epidermal growth factor receptor (cetuximab) and HER2 (trastuzumab), and those inhibiting vascular endothelial growth factor receptor signaling (e.g., bevacizumab). Even though these are among the most used agents in tumor medicine, clinical response to these drugs is reduced due to the emergence of drug resistance as a result of toxic effects in the tumor microenvironment. Research on different types of human cancers has revealed that aberrant expression of miRNAs promotes resistance to the aforementioned drugs. In this study, we review the mechanisms of tumor cell resistance to mAb therapies and the role of miRNAs therein. Emerging treatment strategies combine therapies using innovative miRNA mimics or antagonizers with conventional approaches to maximize outcomes of patients with cancer.

The lauric acid-activated signaling prompts apoptosis in cancer cells

The saturated medium-chain fatty-acid lauric acid (LA) has been associated to certain health-promoting benefits of coconut oil intake, including the improvement of the quality of life in breast cancer patients during chemotherapy. As it concerns the potential to hamper tumor growth, LA was shown to elicit inhibitory effects only in colon cancer cells. Here, we provide novel insights regarding the molecular mechanisms through which LA triggers antiproliferative and pro-apoptotic effects in both breast and endometrial cancer cells. In particular, our results demonstrate that LA increases reactive oxygen species levels, stimulates the phosphorylation of EGFR, ERK and c-Jun and induces the expression of c-fos. In addition, our data evidence that LA via the Rho-associated kinase-mediated pathway promotes stress fiber formation, which exerts a main role in the morphological changes associated with apoptotic cell death. Next, we found that the increase of p21^Cip1/WAF1 expression, which occurs upon LA exposure in a p53-independent manner, is involved in the apoptotic effects prompted by LA in both breast and endometrial cancer cells. Collectively, our findings may pave the way to better understand the anticancer action of LA, although additional studies are warranted to further corroborate its usefulness in more comprehensive therapeutic approaches.

Tianfoshen oral liquid: a CFDA approved clinical traditional Chinese medicine, normalizes major cellular pathways disordered during colorectal carcinogenesis

Colorectal cancer remains the third leading cause of cancer death worldwide, suggesting exploration of novel therapeutic avenues may be useful. In this study, therefore, we determined whether Tianfoshen oral liquid, a Chinese traditional medicine that has been used to treat non-small cell lung cancer, would be therapeutically beneficial for colorectal cancer patients. Our data show that Tianfoshen oral liquid effectively inhibits growth of colorectal cancer cells both in vitro and in vivo. We further employed a comprehensive strategy that included chemoinformatics, bioinformatics and network biology methods to unravel novel insights into the active compounds of Tianfoshen oral liquid and to identify the common therapeutic targets and processes for colorectal cancer treatment. We identified 276 major candidate targets for Tianfoshen oral liquid that are central to colorectal cancer progression. Gene enrichment analysis showed that these targets were associated with cell cycle, apoptosis, cancer-related angiogenesis, and chronic inflammation and related signaling pathways. We also validated experimentally the inhibitory effects of Tianfoshen oral liquid on these pathological processes, both in vitro and in vivo. In addition, we demonstrated that Tianfoshen oral liquid suppressed multiple relevant key players that sustain and promote colorectal cancer, which is suggests the potential therapeutic efficacy of Tianfoshen oral liquid in future colorectal cancer treatments.

Phellinus linteus Grown on Germinated Brown Rice Increases Cetuximab Sensitivity of KRAS-Mutated Colon Cancer

Colon cancer is one of the most common types of cancer, and it has recently become a leading cause of death worldwide. Among colon cancers, the v-ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS)-mutated form is notorious for its non-druggable features. Cetuximab, a monoclonal antibody that binds to the epidermal growth factor receptor, has been introduced as an antitumor therapy; however, secondary resistance and side effects significantly limit its effective use in these cancers. In this study, we prepared Phellinuslinteus on germinated brown rice (PBR) extracts to increase the sensitivity of KRAS-mutated colon cancers to cetuximab. The combined treatment of PBR extract and cetuximab suppressed SW480 cell viability/proliferation, with the cells exhibiting altered cellular morphology and clonogenic potential. AnnexinV–fluorescein isothiocyanate/propidium iodide–stained flow cytometry and Western blotting were performed, and PBR extract combined with cetuximab treatment increased apoptosis of the SW480 cells and suppressed their KRAS protein expression. The potential of PBR as a synergistic anticancer agent was further investigated in a tumor-xenografted mouse model. Tumor growth was significantly suppressed with PBR extract and cetuximab co-treatment. In conclusion, PBR increased the sensitivity of KRAS-mutated colon cancer cells to cetuximab, which indicates the potential use of PBR as a medical food against colon cancer.

Acute resistance exercise modulates microRNA expression profiles: Combined tissue and circulatory targeted analyses

A subset of short non-coding RNAs, microRNAs (miRs), have been identified in the regulation of skeletal muscle hypertrophy and atrophy. Expressed within cells, miRs are also present in circulation (c-miR) and have a putative role in cross-tissue signalling. The aim of this study was to examine the impact of a single bout of high intensity resistance exercise (RE) on skeletal muscle and circulatory miRs harvested simultaneously. Resistance trained males (n = 9, 24.6 ± 4.9 years) undertook a single bout of high volume RE with venous blood and muscle biopsies collected before, 2 and 4hr post-exercise. Real time polymerase chain reaction (Rt-PCR) analyses was performed on 30 miRs that have previously been shown to be required for skeletal muscle function. Of these, 6 miRs were significantly altered within muscle following exercise; miR-23a, -133a, -146a, -206, -378b and 486. Analysis of these same miRs in circulation demonstrated minimal alterations with exercise, although c-miR-133a (~4 fold, p = 0.049) and c-miR-149 (~2.4 fold; p = 0.006) were increased 4hr post-exercise. Thus a single bout of RE results in the increased abundance of a subset of miRs within the skeletal muscle, which was not evident in plasma. The lack a qualitative agreement in the response pattern of intramuscular and circulating miR expression suggests the analysis of circulatory miRs is not reflective of the miR responses within skeletal muscle after exercise.

Integrated genomic analysis of colorectal cancer progression reveals activation of EGFR through demethylation of the EREG promoter

Key molecular drivers that underlie transformation of colonic epithelium into colorectal adenocarcinoma (CRC) are well described. However, the mechanisms through which clinically targeted pathways are activated during CRC progression have yet to be elucidated. Here, we used an integrative genomics approach to examine CRC progression. We used laser capture microdissection to isolate colonic crypt cells, differentiated surface epithelium, adenomas, carcinomas and metastases, and used gene expression profiling to identify pathways that were differentially expressed between the different cell types. We identified a number of potentially important transcriptional changes in developmental and oncogenic pathways, and noted a marked upregulation of EREG in primary and metastatic cancer cells. We confirmed this pattern of gene expression by in situ hybridization and observed staining consistent with autocrine expression in the tumor cells. Upregulation of EREG during the adenoma-carcinoma transition was associated with demethylation of two key sites within its promoter, and this was accompanied by an increase in the levels of epidermal growth factor receptor (EGFR) phosphorylation, as assessed by reverse-phase protein analysis. In CRC cell lines, we demonstrated that EREG demethylation led to its transcriptional upregulation, higher levels of EGFR phosphorylation, and sensitization to EGFR inhibitors. Low levels of EREG methylation in patients who received cetuximab as part of a phase II study were associated with high expression of the ligand and a favorable response to therapy. Conversely, high levels of promoter methylation and low levels of EREG expression were observed in tumors that progressed after treatment. We also noted an inverse correlation between EREG methylation and expression levels in several other cancers, including those of the head and neck, lung and bladder. Therefore, we propose that upregulation of EREG expression through promoter demethylation might be an important means of activating the EGFR pathway during the genesis of CRC and potentially other cancers.

The Role of miR-378a in Metabolism, Angiogenesis, and Muscle Biology

MicroRNA-378a (miR-378a, previously known as miR-378) is one of the small noncoding RNA molecules able to regulate gene expression at posttranscriptional level. Its two mature strands, miR-378a-3p and miR-378a-5p, originate from the first intron of the peroxisome proliferator-activated receptor gamma, coactivator 1 beta (ppargc1b) gene encoding PGC-1β. Embedding in the sequence of this transcriptional regulator of oxidative energy metabolism implies involvement of miR-378a in metabolic pathways, mitochondrial energy homeostasis, and related biological processes such as muscle development, differentiation, and regeneration. On the other hand, modulating the expression of proangiogenic factors such as vascular endothelial growth factor, angiopoietin-1, or interleukin-8, influencing inflammatory reaction, and affecting tumor suppressors, such as SuFu and Fus-1, miR-378a is considered as a part of an angiogenic network in tumors. In the latter, miR-378a can evoke broader actions by enhancing cell survival, reducing apoptosis, and promoting cell migration and invasion. This review describes the current knowledge on miR-378a linking oxidative/lipid metabolism, muscle biology, and blood vessel formation.