MMP-2 Regulation of Emmprin on Tumour Cells and CD73 on Fibroblasts During Tumour-Stromal Interaction.

BACKGROUND/AIM: We previously found that binding between CD73 and extracellular matrix metalloproteinase (MMP) inducer (emmprin) and suppression of CD73 in both tumour cells and fibroblasts suppressed MMP-2 production when co-cultured. However, the importance of CD73 expression in either fibroblasts or cancer cells for cancer invasion remains unknown. In this study, we used siRNA to separately down-regulate CD73 in individual cells, and then performed a 3D co-culture to investigate tumour invasion. MATERIALS AND METHODS: siRNA was used for suppression of CD73 in either fibroblasts (ST353i, HDF) or tumour cells (FU-EPS-1, A431, CRL-2095). Immunoblotting was performed for detecting MMP-2 production after CD73 suppression. 3D-co-cultures were performed for examining tumour invasion. RESULTS: CD73 suppression revealed that CD73 expression on fibroblasts and emmprin on tumour cells were important in regulating MMP-2 production, suggesting that emmprin on tumour cells does not bind CD73 at the cis-manner, but rather at the trans-manner to CD73 present on fibroblasts. CD73 suppression also reduced MMP-2 production at the transcription level and reduced tumour invasion. CONCLUSION: CD73 on fibroblasts acts as a receptor for emmprin, which forms a complex that increases MMP-2 production, possibly resulting in increased invasiveness.

Inhibitory Effect of Pyra-Metho-Carnil on Cancer Spheroid Growth Through Decrease in Glycolysis-associated Molecules.

BACKGROUND/AIM: Pyra-Metho-Carnil (PMC) has been identified as a novel candidate compound for treating numerous malignancies; however, its mechanism of action remains unknown. In this study, we conducted RNA-sequencing (RNA-seq) analyses to elucidate the mechanism of PMC against human colorectal cancer cells harboring mutant KRAS (mtKRAS). MATERIALS AND METHODS: RNA-seq analyses of the HKe3-wild-type KRAS and HKe3-mtKRAS spheroids treated with DMSO or PMC for 6 days were performed. RESULTS: RNA-seq data suggested that PMC treatment suppresses the aerobic glycolysis pathway in HKe3-mtKRAS spheroids through the down-regulation of the HIF1 pathway. Indeed, treatment with PMC markedly suppresses the absorption of glucose by spheroids and the secretion of lactate from them. CONCLUSION: PMC suppresses growth of cancer spheroid through down-regulation of cancer-specific glucose metabolism.

Epipharyngeal Abrasive Therapy Down-regulates the Expression of Cav1.2: A Key Molecule in Influenza Virus Entry.

BACKGROUND/AIM: Influenza A virus (IAV) infection causes an inflammatory response to the respiratory mucosa. The viral glycoprotein hemagglutinin (HA) binds to the sialylated voltage-dependent Ca2+ channel (Cav1.2) in ciliated epithelium. The binding of HA and sialylated Cav1.2 is considered essential to IAV infection, entry, and IAV-induced Ca2+ oscillation. The epipharynx comprises the ciliated epithelium, which is the initial target for viruses that cause upper respiratory tract infections. Previously, we showed that epipharyngeal abrasive therapy (EAT), a treatment for chronic epipharyngitis in Japan, which scratches the epipharyngeal mucosa with a cotton swab containing zinc chloride, induces squamous metaplasia. In this study, we evaluated whether squamous metaplasia by EAT affects the expression patterns of Cav1.2. PATIENTS AND METHODS: The study subjects were seven patients who had not been treated with EAT and 11 patients who had. For the immunohistochemical assessment of the epipharyngeal mucosa, the staining intensity of Cav1.2 was described using the immunohistochemical score (IHC score). RESULTS: The IHC scores for Cav1.2 in the EAT-treated group was 4.19-fold lower than those in the non-treated group (p=0.0034). CONCLUSION: EAT down-regulates the expression of Cav1.2, a key cell surface molecule in influenza virus entry via squamous metaplasia. Thus, EAT may be a simple method for preventing influenza infection.

Epipharyngeal Abrasive Therapy (EAT) Reduces the mRNA Expression of Major Proinflammatory Cytokine IL-6 in Chronic Epipharyngitis.

The epipharynx, located behind the nasal cavity, is responsible for upper respiratory tract immunity; however, it is also the site of frequent acute and chronic inflammation. Previous reports have suggested that chronic epipharyngitis is involved not only in local symptoms such as cough and postnasal drip, but also in systemic inflammatory diseases such as IgA nephropathy and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and Long COVID. Epipharyngeal Abrasive Therapy (EAT), which is an effective treatment for chronic epipharyngitis in Japan, is reported to be effective for these intractable diseases. The sedation of chronic epipharyngitis by EAT induces suppression of the inflammatory cytokines and improves systemic symptoms, which is considered to be one of the mechanisms, but there is no report that has proved this hypothesis. The purpose of this study was to clarify the anti-inflammatory effect of EAT histologically. The study subjects were 8 patients who were not treated with EAT and 11 patients who were treated with EAT for chronic epipharyngitis for 1 month or more. For immunohistochemical assessment, the expression pattern of IL-6 mRNA, which plays a central role in the human cytokine network, was analyzed using in situ hybridization. The expression of IL-6 in the EAT-treated group was significantly lower than those in the EAT nontreated group (p = 0.0015). In addition, EAT suppressed the expression of tumor necrosis factor alpha (TNFα), a crucial proinflammatory cytokine. As a result, continuous EAT suppressed submucosal cell aggregation and reduced inflammatory cytokines. Thus, EAT may contribute to the improvement of systemic inflammatory diseases through the suppression of IL-6 expression.

Cryptotanshinone suppresses tumorigenesis by inhibiting lipogenesis and promoting reactive oxygen species production in KRAS­activated pancreatic cancer cells.

Pyruvate dehydrogenase kinase 4 (PDK4) is an important regulator of energy metabolism. Previously, knockdown of PDK4 by specific small interfering RNAs (siRNAs) have been shown to suppress the expression of Κirsten rat sarcoma viral oncogene homolog (KRAS) and the growth of lung and colorectal cancer cells, indicating that PDK4 is an attractive target of cancer therapy by altering energy metabolism. The authors previously reported that a novel small molecule, cryptotanshinone (CPT), which inhibits PDK4 activity, suppresses the in vitro three­dimensional (3D)­spheroid formation and in vivo tumorigenesis of KRAS­activated human pancreatic and colorectal cancer cells. The present study investigated the molecular mechanism of CPT­induced tumor suppression via alteration of glutamine and lipid metabolism in human pancreatic and colon cancer cell lines with mutant and wild­type KRAS. The antitumor effect of CPT was more pronounced in the cancer cells containing mutant KRAS compared with those containing wild­type KRAS. CPT treatment decreased glutamine and lipid metabolism, affected redox regulation and increased reactive oxygen species (ROS) production in the pancreatic cancer cell line MIAPaCa­2 containing mutant KRAS. Suppression of activated KRAS by specific siRNAs decreased 3D­spheroid formation, the expression of acetyl­CoA carboxylase 1 and fatty acid synthase (FASN) and lipid synthesis. The suppression also reduced glutathione­SH/glutathione disulfide and increased the production of ROS. Knockdown of FASN suppressed lipid synthesis in MIAPaCa­2 cells, partially promoted ROS production and mildly suppressed 3D­spheroid formation. These results indicated that CPT reduced tumorigenesis by inhibiting lipid metabolism and promoting ROS production in a mutant KRAS­dependent manner. This PDK4 inhibitor could serve as a novel therapeutic drug for KRAS­driven intractable cancers via alteration of cell metabolism.

Cancer Spheroid Proliferation Is Suppressed by a Novel Low-toxicity Compound, Pyra-Metho-Carnil, in a Context-independent Manner.

BACKGROUND/AIM: In a screen of compounds to selectively suppress the growth of cancer spheroids, which contained mutant (mt) KRAS, NPD10621 was discovered and associated derivatives were investigated. MATERIALS AND METHODS: Spheroid areas from HCT116-derived HKe3 spheroids expressing wild type (wt) KRAS (HKe3-wtKRAS) and mtKRAS (HKe3-mtKRAS) were treated with 12 NPD10621 derivatives and measured in three-dimensional floating (3DF) cultures. Several cancers were treated with NPD1018 (pyra-metho-carnil: PMC) in 3DF cultures. In a nude mouse assay, 50% cell growth inhibition (GI50) values were determined. RESULTS: From these 12 derivatives, PMC was the most effective inhibitor of HKe3-mtKRAS spheroid growth with the least toxicity. Furthermore, PMC-mediated growth suppression was observed in all tested cancer cell lines, independent of tissue context, driver gene mutations, and drug resistance, suggesting that the PMC target(s) was crucial for cancer growth in a context-independent manner. The GI50 value of PMC in nude mice assay was 7.7 mg/kg and nude mice that were administered 40 mg/kg PMC for 7 days did not show any abnormal blood cell count values. CONCLUSION: PMC is a low-toxicity compound that inhibits the growth of different tumor cell types.

Chitinase 3-like 1, Carcinoembryonic Antigen-related Cell Adhesion Molecule 6, and Ectopic Claudin-2 in the Carcinogenic Processes of Ulcerative Colitis.

BACKGROUND/AIM: The cumulative cancerous rate of colitis-associated cancer (CAC) has increased exponentially in patients with ulcerative colitis (UC). We have investigated the factors involved in the carcinogenic processes of CAC among UC patients. PATIENTS AND METHODS: A total of 42 UC patients who underwent surgical treatments between January 2001 and December 2010 at Kurume University Hospital (Fukuoka, Japan) were enrolled. We conducted this study using 3 cases of CAC out of 42 UC cases and 1 case of colorectal cancer. cDNA microarray analyses were performed using normal, inflamed, and cancerous tissues from surgical CAC specimens and protein expression was confirmed by immunohistochemical analyses. RESULTS: cDNA microarray revealed 32 genes that were dominantly expressed in tumorous regions of CAC. Gene ontology analysis revealed that these genes were involved in inflammatory responses and cytokine-cytokine receptor interactions. Chitinase 3-like1 (CHI3L1), carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6), and Claudin-2 (CLND2) were selected from CAC-related genes as candidate molecules. Immunostaining revealed strong expression of each protein in cancerous regions. CONCLUSION: In this study, we identified CAC-related genes and found that CHI3L1, CEACAM6, and CLND2 were expressed in patient samples. All the above genes were associated with adherent invasive Escherichia coli (AIEC), which suggested that these molecules are likely involved in AIEC infection. Further analyses would be required to reveal unknown mechanisms of CAC-related genes in the tumor microenvironment.

Standardized Methods Using EUS-guided Fine-needle Biopsy and a Minimal Medium Creates Three Pancreatic Cancer Organoids.

BACKGROUND/AIM: Recently, endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) has been conducted for diagnosing pancreatic ductal adenocarcinoma (PDAC), after which obtained samples were used in organoid cultures. However, no standardized method for PDAC organoid cultures exists. Therefore, to standardize or simplify sample collection and culture methods for PDAC organoids, we performed a floating culture using non-minced specimens obtained by EUS-FNB in a minimal medium, lacking growth factors or inhibitors for pancreatic organoids. PATIENTS AND METHODS: A total of 38 patients with clinically diagnosed PDAC were enrolled in the study. First, EUS-FNB was conducted using a 22- or 25-gauge biopsy needle. Then, a surplus of samples was collected for organoid formation after rapid on-site cytological evaluations of sample adequacy. Subsequently, the established organoids were compared with clinical data and pathological diagnosis, following periodic observations and evaluations for morphology. RESULTS: PDAC organoids were successfully created in 24 of the 38 cases (63.2%), including four cases with pathologically inconclusive EUS-FNB results. Afterward, PDAC organoid morphology was classified into ductal, dormant, and adhesive small cluster (ASC) types. Although the ductal and ASC types were seen separately, they were also seen together in other cases, which we named "mixed type". CONCLUSION: We propose a feasible and straightforward method for establishing organoids, especially for diagnosing PDAC, particularly when the result of EUS-FNB is pathologically inconclusive. Furthermore, PDAC organoids are morphologically classified into three types reported for the first time.

Epipharyngeal Abrasive Therapy (EAT) Has Potential as a Novel Method for Long COVID Treatment.

COVID-19 often causes sequelae after initial recovery, referred to collectively as long COVID. Long COVID is considered to be caused by the persistence of chronic inflammation after acute COVID-19 infection. We found that all long COVID patients had residual inflammation in the epipharynx, an important site of coronavirus replication, and some long COVID symptoms are similar to those associated with chronic epipharyngitis. Epipharyngeal abrasive therapy (EAT) is a treatment for chronic epipharyngitis in Japan that involves applying zinc chloride as an anti-inflammatory agent to the epipharyngeal mucosa. In this study, we evaluated the efficacy of EAT for the treatment of long COVID. The subjects in this study were 58 patients with long COVID who were treated with EAT in the outpatient department once a week for one month (mean age = 38.4 ± 12.9 years). The intensities of fatigue, headache, and attention disorder, which are reported as frequent symptoms of long COVID, were assessed before and after EAT using the visual analog scale (VAS). EAT reduced inflammation in the epipharynx and significantly improved the intensity of fatigue, headache, and attention disorder, which may be related to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). These results suggest that EAT has potential as a novel method for long COVID treatment.

Growth Suppression of Cancer Spheroids With Mutated KRAS by Low-toxicity Compounds from Natural Products.

BACKGROUND/AIM: Among compounds from natural products selectively suppressing the growth of cancer spheroids, which have mutant (mt) KRAS, NP910 was selected and its derivatives explored. MATERIALS AND METHODS: The area of HKe3 spheroids expressing wild type (wt) KRAS (HKe3-wtKRAS) and mtKRAS (HKe3-mtKRAS) were measured in three-dimensional floating (3DF) cultures treated with 18 NP910 derivatives. The 50% cell growth inhibition (GI50) was determined by long-term 3DF (LT3DF) culture and nude mice assay. RESULTS: We selected NP882 (named STAR3) as the most effective inhibitor of growth of HKe3-mtKRAS spheroids with the least toxicity among NP910 derivatives. GI50s of STAR3 in LT3DF and nude mice assay were 6 µM and 30.75 mg/kg, respectively. However, growth suppression by STAR3 was observed in 50% of cell lines independent of KRAS mutation, suggesting that the target of STAR3 was not directly associated with KRAS mutation and KRAS-related signals. CONCLUSION: STAR3 is a low-toxicity compound that inhibits growth of certain tumour cells.

Oncogenic KRAS mutations enhance amino acid uptake by colorectal cancer cells via the hippo signaling effector YAP1.

Oncogenic KRAS mutations develop unique metabolic dependencies on nutrients to support tumor metabolism and cell proliferation. In particular, KRAS mutant cancer cells exploit amino acids (AAs) such as glutamine and leucine, to accelerate energy metabolism, redox balance through glutathione synthesis and macromolecule biosynthesis. However, the identities of the amino acid transporters (AATs) that are prominently upregulated in KRAS mutant cancer cells, and the mechanism regulating their expression have not yet been systematically investigated. Here, we report that the majority of the KRAS mutant colorectal cancer (CRC) cells upregulate selected AATs (SLC7A5/LAT1, SLC38A2/SNAT2, and SLC1A5/ASCT2), which correlates with enhanced uptake of AAs such as glutamine and leucine. Consistently, knockdown of oncogenic KRAS downregulated the expression of AATs, thereby decreasing the levels of amino acids taken up by CRC cells. Moreover, overexpression of mutant KRAS upregulated the expression of AATs (SLC7A5/LAT1, SLC38A2/SNAT2, and SLC1A5/ASCT2) in KRAS wild-type CRC cells and mouse embryonic fibroblasts. In addition, we show that the YAP1 (Yes-associated protein 1) transcriptional coactivator accounts for increased expression of AATs and mTOR activation in KRAS mutant CRC cells. Specific knockdown of AATs by shRNAs or pharmacological blockage of AATs effectively inhibited AA uptake, mTOR activation, and cell proliferation. Collectively, we conclude that oncogenic KRAS mutations enhance the expression of AATs via the hippo effector YAP1, leading to mTOR activation and CRC cell proliferation.

Mutant KRAS Promotes NKG2D+ T Cell Infiltration and CD155 Dependent Immune Evasion.

BACKGROUND/AIM: Roles for mutant (mt) KRAS in the innate immune microenvironment in colorectal cancer (CRC) were explored. MATERIALS AND METHODS: Human CRC HCT116-derived, mtKRAS-disrupted (HKe3) cells that express exogenous mtKRAS and allogenic cytokine-activated killer (CAK) cells were co-cultured in 3D floating (3DF) culture. The anti-CD155 antibody was used for function blocking and immuno histochemistry. RESULTS: Infiltration of CAK cells, including NKG2D+ T cells, into the deep layer of HKe3-mtKRAS spheroids, was observed. Surface expression of CD155 was found to be up-regulated by mtKRAS in 3DF culture and CRC tissues. Further, the number of CD3+ tumor-infiltrating cells in the invasion front that show substantial CD155 expression was significantly larger than the number showing weak expression in CRC tissues with mtKRAS. CD155 blockade decreased the growth of spheroids directly and indirectly through the release of CAK cells. CONCLUSION: CD155 blockade may be useful for therapies targeting tumors containing mtKRAS.

MK615 Suppresses Hypoxia Tolerance by Up-regulation of E-cadherin in Colorectal Cancer Cells With Mutant KRAS.

BACKGROUND/AIM: The Japanese apricot "Prunus mume" is a traditional Japanese medicine. MK615, a compound extract from Prunus mume has been reported to have anti-tumor effects. Herein, we used 3D floating (3DF) culture to evaluate the anticancer effects of MK615 against human colorectal cancer (CRC) cells that contain mutant (mt) KRAS. MATERIALS AND METHODS: HKe3 cells exogenously expressing mtKRAS (HKe3-mtKRAS) were treated with MK615 in 3DF cultures. The protein levels of hypoxia-inducible factor 1 (HIF-1) and E-cadherin were quantified by western blotting. RESULTS: MtKRAS enhanced hypoxia tolerance via up-regulation of HIF-1. The expression of HIF-1 protein was suppressed by constitutive overexpression of E-cadherin in CRC HCT116 spheroids. MK615 increased the expression of E-cadherin and decreased the expression of HIF-1 in HKe3-mtKRAS. These results suggest that MK615 suppresses hypoxia tolerance by up-regulation of E-cadherin in CRC cells with mtKRAS. CONCLUSION: MK615 exhibits properties useful for the potential treatment of CRC patients with mtKRAS.

A novel compound, ferulic acid-bound resveratrol, induces the tumor suppressor gene p15 and inhibits the three-dimensional proliferation of colorectal cancer cells.

Resveratrol, a phytoalexin present in grapes and other edible foods, has been reported to have beneficial effects against various diseases including cancer. We previously reported that resveratrol and its derivative, caffeic acid-adducted resveratrol, selectively inhibit the three-dimensional (3D) proliferation of a human colorectal cancer cell line, HCT116 with activating KRAS mutation. Herein, we demonstrated that a novel compound, ferulic acid-bound resveratrol, also represses the 3D proliferation of HCT116 cells. We observed that resveratrol conjugated to two ferulic acids represses the 3D proliferation of HCT116 cells more strongly than resveratrol and resveratrol conjugated to one ferulic acid. Resveratrol conjugated to two ferulic acids also inhibited the 3D proliferation of MCF7 human breast cancer cells. We further uncovered that the resveratrol derivative increases the mRNA level of the tumor suppressor p15, a CDK inhibitor that functions as a brake of cell proliferation in HCT116 cells. These results imply that the resveratrol derivative represses 3D proliferation via increasing p15 expression in HCT116 cells.

Zfat Is Indispensable for the Development of Erythroid Cells in the Fetal Liver.

BACKGROUND/AIM: In mice, fetal liver is the first tissue of definitive erythropoiesis for definitive erythroid expansion and maturation. ZFAT, originally identified as a candidate susceptibility gene for autoimmune thyroid disease, has been reported to be involved in primitive hematopoiesis and T cell development. The aim of this study was to examine whether or not Zfat is involved in definitive erythropoiesis in the fetal liver during mammalian development. MATERIALS AND METHODS: The role of Zfat during mouse fetal erythropoiesis in the fetal liver was examined using tamoxifen-inducible CreERT2 Zfat-deficient mice. RESULTS: Zfat-deficient mice exhibit moderate anemia with small and pale fetal liver through a decreased number of erythroblasts by E12.5. Apoptosis sensitivity in fetal liver erythroid progenitors was enhanced by Zfat-deficiency ex vivo. Moreover, Zfat knockdown partially inhibited CD71-/lowTer119- to CD71highTer119- transition of fetal liver erythroid progenitors with impairment in the elevation of CD71 expression. CONCLUSION: Zfat plays a critical role for erythropoiesis in the fetal liver.

Transcriptional and metabolic rewiring of colorectal cancer cells expressing the oncogenic KRASG13D mutation.

BACKGROUND: Activating mutations in KRAS frequently occur in colorectal cancer (CRC) patients, leading to resistance to EGFR-targeted therapies. METHODS: To better understand the cellular reprogramming which occurs in mutant KRAS cells, we have undertaken a systems-level analysis of four CRC cell lines which express either wild type (wt) KRAS or the oncogenic KRASG13D allele (mtKRAS). RESULTS: RNAseq revealed that genes involved in ribosome biogenesis, mRNA translation and metabolism were significantly upregulated in mtKRAS cells. Consistent with the transcriptional data, protein synthesis and cell proliferation were significantly higher in the mtKRAS cells. Targeted metabolomics analysis also confirmed the metabolic reprogramming in mtKRAS cells. Interestingly, mtKRAS cells were highly transcriptionally responsive to EGFR activation by TGFα stimulation, which was associated with an unexpected downregulation of genes involved in a range of anabolic processes. While TGFα treatment strongly activated protein synthesis in wtKRAS cells, protein synthesis was not activated above basal levels in the TGFα-treated mtKRAS cells. This was likely due to the defective activation of the mTORC1 and other pathways by TGFα in mtKRAS cells, which was associated with impaired activation of PKB signalling and a transient induction of AMPK signalling. CONCLUSIONS: We have found that mtKRAS cells are substantially rewired at the transcriptional, translational and metabolic levels and that this rewiring may reveal new vulnerabilities in oncogenic KRAS CRC cells that could be exploited in future.

Acquisition of resistance to vemurafenib leads to interleukin-10 production through an aberrant activation of Akt in a melanoma cell line.

Serine/threonine-protein kinase B-Raf (BRAF) inhibitors are very effective in treating melanoma with BRAF mutations. BRAF inhibitors suppress aberrant growth of melanoma cells caused by BRAF mutations. BRAF mutations reportedly result in melanoma cells releasing immunosuppressive factors, and BRAF inhibitors elicit anti-melanoma immune responses by reducing such factors. However, immunological characteristics of tumor cells that acquire resistance to BRAF inhibitors remain unknown. Here, we compared immunological characteristics between a melanoma cell line and its vemurafenib-resistant subline. No differences were observed in the status of BRAF mutations, expression of surface molecules related to antitumor T-cell responses or recognition by human leukocyte antigen-A*0201-matched melanoma-specific cytotoxic T lymphocytes in a short-term co-culture assay. However, resistant tumor cells released high amounts of interleukin-10 depending on aberrant activation of Akt signaling, and dendritic cell functions were considerably suppressed by culture supernatants of the resistant cells. Our findings demonstrated a novel immunological mechanism contributing to tumor growth owing to drug resistance to BRAF inhibitors.

Growth Suppression of Human Colorectal Cancer Cells with Mutated KRAS by 3-Deaza-cytarabine in 3D Floating Culture.

BACKGROUND/AIM: During screening for compounds that selectively suppress growth of human colorectal cancer (CRC) spheroids with mutant (mt) KRAS, the uridine analogue, 5-bromouridine (BrUrd) was identified and its derivatives were explored. MATERIALS AND METHODS: DNA incorporation in two-dimensional (2D) and three-dimensional floating (3DF) cultures was examined with the uridine analogue, 5-ethynyl-2'-deoxyuridine (EdU). The area of HKe3 CRC spheroids expressing wild type (wt) KRAS (HKe3-wtKRAS) and mtKRAS (HKe3-mtKRAS) were measured in 3DF culture with 11 BrUrd derivatives. RESULTS: EdU was strongly incorporated into newly-synthesized DNA from HKe3-mtKRAS cells compared to HKe3-wtKRAS in 2D and 3DF culture. 3-Deaza-cytarabine, which has properties of BrUrd and cytidine, was the most effective inhibitor of HKe3-mtKRAS spheroids with the least toxicity to HKe3-wtKRAS. Growth suppression of 3-deaza-cytarabine was stronger than cytarabine in 2D culture, and toxicity was lower than gemcitabine in long-term 3DF culture. CONCLUSION: 3-Deaza-cytarabine exhibits properties useful for the treatment of CRC patients with mtKRAS.

A novel resveratrol derivative selectively inhibits the proliferation of colorectal cancer cells with KRAS mutation.

Resveratrol is a polyphenolic compound in many edible foods including grapes, peanuts, and berries. Several studies have revealed the beneficial effects of resveratrol against various diseases such as heart disease, diabetes, obesity, neurological disorders, and cancer. A recent study showed that resveratrol inhibits the proliferation of HCT116 human colorectal cancer cells in three-dimensional culture (3DC) via induction of luminal apoptosis in HCT116 cell spheroids. In this study, we showed that a novel compound, caffeic acid-adducted resveratrol, has a stronger inhibitory effect on the growth of HCT116 cell spheroids in 3DC than resveratrol. It showed almost the same inhibitory efficacy as 5-fluorouracil, a conventional anticancer drug. We further showed that the resveratrol derivative did not affect the growth of HKe3 cell spheroids derived from HCT116 cells by disruption of the activating mutant KRAS gene. These results suggest that the resveratrol derivative inhibits the growth of HCT116 cell spheroids via inhibition of an oncogenic KRAS-mediated signaling pathway.

The Long Noncoding RNA OIP5-AS1 Is Involved in the Regulation of Cell Proliferation.

BACKGROUND/AIM: OPA-interacting protein 5 antisense transcript 1 (OIP5-AS1) is a long noncoding RNA located on human chromosome 15q15.1 and transcribed in the opposite direction to OIP5. Here, we report that OIP5-AS1 is involved in regulating cell proliferation. MATERIALS AND METHODS: HeLa cells were transfected with OIP5-AS1-targeting siRNA oligonucleotides and anti-sense oligonucleotides. The cells were harvested 72 h after transfection and subjected to quantitative reverse transcription-polymerase chain reaction (qRT-PCR), and cell-cycle and apoptosis analysis. RESULTS: OIP5-AS1 was expressed at a lower level in cells harbouring an oncogenic kirsten rat sarcoma viral oncogene homolog (K-RAS) mutation than in cells expressing wild-type K-RAS. Silencing OIP5-AS1 with siRNA oligonucleotides or anti-sense oligonucleotides reduced HeLa cell proliferation. Apoptosis and cell-cycle analysis showed that silencing OIP5-AS1 did not cause apoptosis, but did cause G2/M phase cell-cycle arrest. CONCLUSION: These results suggest that OIP5-AS1 positively regulates cell proliferation by promoting G2/M phase progression.