Aberrant DNA Methylation in Human Cancers

DNA methylation, one of the best-characterized epigenetic modifications, plays essential roles in diseases, including human cancers. In recent years, our understanding on DNA methylation with human cancers has made significant progress, which was facilitated by stunning development in the analysis of the human methylome of multiple cancer types. In this review, recent developments in the characterization of aberrant DNA methylation involved in human cancers development were discussed with special emphasis on the mechanisms of aberrant DNA methylation in human cancers. We also summarize the recent treatment strategy for human cancers with de-methylation drugs.

Carcinogen-Macromolecular Adducts As Biomarkers in Human Cancer Risk Assessment

Substantial data have been generated during the past 5 years in both experimental systems and human populations which shed light on the potential role of carcinogen-macromolecular adducts in human cancer risk assessment. The use of DNA and protein adducts is based on the fundamental concept in chemical carcinogenesis that most genotoxins are metabolized to electrophilic 'ultimate' carcinogens that are capable of forming covalent adducts with cellular macromolecules. This report examines the relative usefulness and limitations of using DNA and protein adducts and related techniques for assessing human exposure to genotoxic carcinogens. Data discussed in this report clearly demonstrate that these biomarkers not only allow early detection of potential cancer hazard in humans, but they can also significantly increase the power of conventional cancer epidemiological studies in determining true causal relationships. In addition, such biomarkers can improve extrapolation of cancer risks from laboratory animals to humans or from one human population to another.

Studies on hematoporphyrin-photosensitized effects on human cancer cells in vitro——TEM and SEM observation

The ECa109 esophageal cancer epithelial cell line cells was treated with hematoporphyrin one hour and followed by irrediation with 20W black light at a distance of two cm for ten minutes.The cancer cells were examined by TEM and SEM after treatment for one,three and five days.By exposure to hematoporphyrin derivative(HpD)and photoirradiation,the proportion of dark-cells with high electron density were decreased and the proportion of empty cells with low electron density was increased.The latter showed distruction of cancer cells.

Met as a target in human cancer

Inappropriate Met-hepatocyte growth factor/scatter factor （HGF/SF） signaling is a hallmark of most types of solid tumors in humans and often correlates with poor prognosis. There are several mechanisms by which Met signaling is deregulated including Met and/or HGF/SF overexpression, mutation, autocrine signaling, and ligand-independent activation. Because Met is an attractive therapeutic target for a multitude of cancers, extensive research towards finding Met and HGF/SF inhibitors is ongoing.？ In parallel with these efforts, several mouse models have been developed in our lab that will be valuable for preclinical testing of Met-targeted therapeutics.

World’s First Myoblast Treatment of Human Cancer Found Safe and Efficacious

Evolution of placental mammals over the past 160 million years witnesses the relative sparing of muscles from cancer attacks. In 1) nude mice with human gastrointestinal or lung tumors, and 2) human subjects with liver, lung or gastrointestinal tumors, intra-tumor implantation of allogeneic human myoblasts induced cancer apoptosis, inhibiting metastasis and tumor growth. We postulate four mechanisms of cancer apoptosis: a) myoblasts releasing tumor necrosis factor-α (TNF-α);b) deprivation of nutrients and oxygen;c) local inflammatory and immunologic attacks;and d) prevention from metastasis. These basic and clinical studies demonstrated preliminary safety and efficacy of intra-tumor myoblast implantation in the development of prevention and treatment for cancer, now the number one disease killer of mankind.

Unraveling links between aging,circadian rhythm and cancer:Insights from evidence-based analysis

Aging and circadian rhythms have been connected for decades,but their molecular interaction has remained unknown,especially for cancers.In this situation,we summarized the current research actuality and problems in this field using the bibliometric analysis.Publications in the PubMed and Web of Science databases were retrieved.Overall,there is a rising trend in the publication volume regarding aging and circadian rhythms in the field of cancer.Researchers from USA,Germany,Italy,China and England have greater studies than others.Top three publication institutions are University of California System,UDICE-French Research Universities and University of Texas System.Current research hotspots include oxidative stress,breast cancer,melatonin,cell cycle,calorie restriction,prostate cancer and NF-κB.In conclusion,results generated by bibliometric analysis indicate that many approaches involve in the complex interactions between aging and circadian rhythm in cancer.These established and emerging research directions guide our exploration of the regulatory mechanisms of aging and circadian rhythms in cancer and provide a reference for developing new research avenues.

Tyrosine kinase inhibitors and human epidermal growth factor receptor-2 positive breast cancer

The body of evidence investigating human epidermal growth factor receptor-2(HER2)directed therapy in patients with breast cancer(BC)has been growing within the last decade.Recently,the use of tyrosine kinase inhibitors(TKIs)has been of particular interest in the treatment of human malignancies.This literature commentary is intended to highlight the most recent findings associated with the widely-studied TKI agents and their clinical significance in improving the outcomes of HER2 positive BC.

Disitamab vedotin combined with apatinib in gastric cancer: A case report and review of literature

BACKGROUND In patients with human epidermal growth factor receptor 2(HER2)-overex-pressing gastric cancer(GC),the combination of HER2 targeting and a standard first-line chemotherapy regimen has been demonstrated to significantly improve their prognosis.However,in a proportion of patients,cancer progresses within a short period of time,and there is currently no standard treatment after disease progression.CASE SUMMARY This study presents a case of a 51-year-old male with advanced GC who un-derwent radical resection(Billroth type II subtotal gastrectomy and gastrojejun-ostomy)and resection of liver metastases.Immunohistochemical staining revealed a HER2 score of 2+,a dMMR status,and a Ki67 proliferation index of 30%to 40%.The gene test results indicated the presence of ERBB2 amplification and a PD-L1 expression level of less than 5%.Since December 2021,the patient has experienced disease progression during both first-line(two cycles of KN026 combined with KN046)and second-line(five cycles of nivolumab combined with trastuzumab and SOX chemotherapy)treatment regimens.The patient's prognosis following the first and second lines of treatment was unfavorable,with pro-gression occurring in a relatively short time.For third-line therapy,disitamab vedotin(RC48)plus apatinib was used.At the time of this report,the patient had achieved a progression-free survival(PFS)of 25.8 months,which exceeded the median survival time for patients with advanced GC.CONCLUSION Despite the unfavorable prognosis associated with advanced GC,the imple-mentation of personalized treatment approaches may still prove beneficial for select patients.In patients with HER2-positive GC with extensive metastatic involvement,the use of the HER2-targeted combination with apatinib has demonstrated the potential to prolong both PFS and overall survival.

Induction of apoptosis and G2/M cell cycle arrest by oridonin in human gastric cancer BGC-823 cells

Aim To investigate in vitro apoptosis-induction effects of oridonin on gastric tumor cells BGC-823 and its effects on cell cycle, mitochondrial membrane potential and intracellular Ca^2＋ to shed light on the mode of its anticancer action. Methods The MTT method was used to investigate the inhibitory effect of oridonin on BGC-823 cells. The apoptosis-induction effect was evaluated by confocal laser microscopy and flow cytometry. The change of mitochondrial membrane potential and the increase of intracellular Ca^2＋ were assessed by fluorescence probe rhodamine123 and Fluo 3-AM, respectively, with flow cytometry. The expression of apoptosis and cell cycle related proteins was studied using western blotting. Results Oridonin inhibited BGC-823 cells growth with IC50 of 22.21 p, mol.L^-1. It induced apoptosis in a dose-dependent manner. In addition, it decreased mitochondria membrane potential, increased intracellular Ca^2＋, and activated pro-caspase 3. BGC-823 cells were arrested in G2/M cell cycle phase with lower expression of cyclin A protein. The up-regulation of p53 was observed before apoptosis and cell cycle arrest occurred. Conclusion Oridonin inhibits the proliferation of BGC-823 cells through G2/M cell cycle arrest and apoptosis induction, which is mediated by influx of Ca^2＋, up-regulation of p53, activation of caspase-3, and down-regulation of cyclin A.

Mutation analysis of large tumor suppressor genes LATS1 and LATS2 supports a tumor suppressor role in human cancer

In recent years, human cancer genome projects provide unprecedented opportunities for the discovery of cancer genes and signaling pathways that contribute to tumor development. While numerous gene mutations can be identified from each cancer genome, what these muta- tions mean for cancer is a challenging question to address, especially for those from less understood putative new cancer genes. As a powerful approach, in silico bioinformatics analysis could efficiently sort out mutations that are predicted to damage gene function. Such an analysis of human large tumor suppressor genes, LATS1 and LATS2, has been carried out and the results support a role of hLATS1/12 as negative growth regulators and tumor suppressors.

Parasporal Proteins from Bacillus thuringiensis and Their Cytotoxicity on Human Cancer Cells

Parasporins(PSs) represent a novel functional category of crystal proteins(Cry) produced by non-insecticidal Bacillus thuringiensis. A distinct feature for PSs is their specific cytotoxicity against human cancer cells from diverse origins, other than hemolytic or insecticidal activity. As structurally/functionally Cry proteins, parasporins are expressed as protoxins that require protease cleavage for activation. Currently,identified PSs is classified into 6 groups: PS1, PS2, PS3, PS4, PS5 and PS6, which are heterogeneous in cytotoxic spectrum and activity level. Some PSs have been explored for their mode of anticancer activities, reports mainly include pore formation induced by binding to putative receptors on cell membrane and apoptosis by intracellular Ca2+concentration. Further work should focus on the identification of new PS or PS homologs and better understanding of their anticancer mechanism before possible application in cancer therapy.

Effects of transferred NK4 gene on proliferation, migration, invasion and apoptosis of human prostate cancer DU145 cells

We investigated the ability of NK4, an antagonist of human hepatocyte growth factor （HGF）, to inhibit the influence of HGF on proliferation, migration, invasion and apoptosis of human prostate cancer cells. Expression vector pBudCE4.1-EGFP-NK4 containing NK4 cDNA was used to transfect human prostate cancer DU145 cells, and the effects of the autocrine NK4 on tumor cell proliferation, migration, invasion and apoptosis were assessed in vitro. in vivo, we subcutaneously implanted DU145 cells, mock-transfected clone （DU145/empty vector） cells and NK4- transfected clone （DU145/NK4） cells into nude mice, and then evaluated tumor growth, cell proliferation and cell apoptosis in vivo. We found that DU145/NK4 cells expressed NK4 protein. In the in vitro study, autocrine NK4 at- tenuated the HGF-induced tumor cell proliferation, migration and invasion, and stimulated apoptosis. Furthermore, autocrine NK4 effectively inhibited the HGF-induced phosphorylation of c-Met, extracellular signal-regulated kinase-1 （ERK1）. and protein kinase B 1/2 （Aktl/2）. Histological examination revealed that autocrine NK4 inhibited prolifera- tion and accelerated apoptosis of prostate cancer cells. These results show that genetic modification of DU145 cells with NK4 cDNA yields a significant effect on their proliferation, migration, invasion and apoptosis. Molecular targeting of HGF/c-Met by NK4 could be applied as a novel therapeutic approach to prostate cancer.

Epigenetic modification regulates both expression of tumor-associated genes and cell cycle progressing in human colon cancer cell lines: Colo-320 and SW1116

The aim of this study is to assess the effects of DNA methylation and historic acetylation, alone or in combination, on the expression of several tumor-associated genes and cell cycle progression in two established human colon cancer cell lines: Colo-320 and SW1116. Treatments with 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A, alone or in combination, were applied respectively. The methylation status of the CDKN2A promoter was determined by methyla-tion-specific PCR, and the acetylated status of the histones associated with the p21WAF1 and CDKN2A genes was examined by chromatin immunoprecipitation. The expression of the CDKN2A, p21WAF1, p53, p73, APC, c-myc, c-Ki-ras and survivin genes was detected by real-time RT-PCR and RT-PCR. The cell cycle profile was established by flow cytometry. We found that along with the demethylation of the CDKN2A gene promoter in both cell lines induced by 5-aza-dC alone or in combination with TSA, the expression of both CDKN2A and APC genes increased. The treatment of TSA or sodium butyrate up-regulated the transcription of p21WAF1 significantly by inducing the acetylation of histones H4 and H3, but failed to alter the acetylation level of CDKN2A-associated histones. No changes in transcription of p53, p73, c-myc, c-Ki-ras and survivin genes were observed. In addition, TSA or sodium butyrate was shown to arrest cells at the G1 phase. However, 5-aza-dC was not able to affect the cell cycle progression. In conclusion, regulation by epigenetic modification of the transcription of tumor-associated genes and the cell cycle progression in both human colon cancer cell lines Colo-320 and SW1116 is gene-specific.

The role of TRPC6 in HGF-induced cell proliferation of human prostate cancer DU145 and PC3 cells

Hepatocyte growth factor （HGF） is a glycoprotein that induces prostate cancer cell proliferation, migration and invasion. The activation of transient receptor potential canonical 6 （TRPC6） channels is considered important in promoting prostate cancer cell proliferation. In this study, we assessed the role of endogenous TRPC6 channels in the HGF-induced cell proliferation of prostate cancer. Reverse transcription-PCR and Western blotting were used to investigate TRPC6 expression. Electrophysiological techniques （whole-cell patch clamp configuration） and Ca^2＋ imaging analysis were used to investigate the channel activity in cells. The effects of TRPC6 channels on cell cycle progression, cell apoptosis and cell growth were also examined. TRPC6 and c-MET were expressed in DU145 and PC3 cells. In addition, functional TRPC6 channels were present in DU145 and PC3 cells, and TRPC6 knockdown suppressed TRPC-Iike currents evoked by oleoyl-2-acetyl-sn-glycerol （OAG）. Inhibition of TRPC6 channels in DU145 and PC3 cells abolished OAG- and HGF-induced Ca^2＋ entry. Furthermore, inhibition of TRPC6 channels arrested DU145 and PC3 cells at the G2/M phase and suppressed HGF-induced cell proliferation. Collectively, our results indicate that TRPC6 has an important role in HGF-induced DU145 and PC3 cell proliferation.

Expression of cell cycle regulator p57^(kip2), cyclinE protein and proliferating cell nuclear antigen in human pancreatic cancer: An immunohistochemical study

AIM： To investigate the effects of p57^kip2, cyclinE protein and proliferating cell nuclear antigen （PCNA） on occurrence and progression of human pancreatic cancer. METHODS： The expression of p57^kip2, cyclinE protein and PCNA in tumor tissues and adjacent tissues from 32 patients with pancreatic cancer was detected by SP immunohistochemical technique. RESULTS： The positive expression rate of p57^kip2 protein in tumor tissues was 46.9%, which was lower than that in adjacent pancreatic tissues （χ^2 = 5.317, P〈0.05）. p57^kip2 protein positive expression remarkably correlated with tumor cell differentiation （P〈0.05）, but not with lymph node metastasis （P〉0.05）. The positive expression rate of cyclinE protein in tumor tissues was 68.8%, which was higher than that in adjacent pancreatic tissues （χ^2 = 4.063, P〈0.05）. CyclinE protein positive expression significantly correlated with tumor cell differentiation and lymph node metastasis （P〈0.05）. The positive expression rate of PCNA in the tumor tissues was 71.9%, which was higher than that in adjacent pancreatic tissues （χ^2 = 5.189, P〈0.05）. PCNA positive expression remarkably correlated with tumor cell differentiation and lymph node metastasis （P〈0.05）. CONCLUSION： The decreased expression of p57^kip2 and/or overexpression of cyclinE protein and PCNA may contribute to the occurrence and progression of pancreatic cancer. p57^kip2, cyclinE protein, and PCNA play an important role in occurrence and progression of pancreatic cancer.

Radiosensitivity of human colon cancer cell enhanced by immunoliposomal docetaxel

AIM:To enhance the radiosensitivity of human colon cancer cells by docetaxel. METHODS: Immunoliposomal docetaxel was prepared by coupling monoclonal antibody against carcinoembryonic antigen to cyanuric chloride at the PEG terminus of liposome. LoVo adenocarcinoma cell line was treated with immunoliposomal docetaxel or/and irradiation. MTT colorimetric assay was used to estimate cytotoxicity of immunoliposomal docetaxel and radiotoxicity. Cell cycle redistribution and apoptosis were determined with flow cytometry. Survivin expression in LoVo cells was verified by immunohistochemistry. D801 morphologic analysis system was used to semi-quantify immunohistochemical staining of survivin. RESULTS: Cytotoxicity was induced by immunoliposomal docetaxel alone in a dose-dependent manner. Immunoliposomal docetaxel yielded a cytotoxicity effect at a low dose of 2 nmol/L. With a single dose irradiation, the relative surviving fraction of LoVo cells showed a dose-dependent response, but there were no significant changes as radiation delivered from 4 to 8 Gy. Compared with liposomal docetaxel or single dose irradiation, strongly radiopotentiating effects of immunoliposomal docetaxel on LoVo cells were observed. A low dose of immunoliposomal docetaxel could yield sufficient radiosensitivity. Immunoliposomal docetaxel were achieved both specificity of the conjugated antibody and drug radiosensitization. Combined with radiation, immunoliposomal docetaxel significantly increased the percentage of G2/M cells and induced apoptosis, but significantly decreased the percentage of cells in G2/G1 and S phase by comparison with liposomal docetaxel. Immunohistochemical analysis showed that the brown stained survivin was mainly in cytoplasm of LoVo cells. Semi-quantitative analysis of the survivin immunostaining showed that the expression of survivin in LoVo cells under irradiation with immunoliposomal docetaxel was significantly decreased. CONCLUSION: Immunoliposomal docetaxel is strongly effective for target radiosensitation in LoVo colon carcinoma cells, and may offer the potential to improve local radiotherapy.

PGC-la induces apoptosis in human epithelial ovarian cancer cells through a PPARy-dependent pathway

Peroxisome proliferator-activated receptor gamma （PPAR）,） coactivator-1 alpha （PGC-1α） coactivates multiple transcription factors and regulates several metabolic processes. The current study investigated the role of PGC-1α in the induction of apoptosis in human epithelial ovarian cancer cells. The PGC-1α mRNA level between human ovaries and human ovarian epithelial tumors was examined by quantitative RT-PCR. Less PGC- 1α expression was found in the surface epithelium of malignant tumors compared with normal ovaries. Overexpression of PGC-1α in human epithelial ovarian cancer cell line Ho-8910 induced cell apoptosis through the coordinated regulation of Bcl-2 and Bax expression. Microarray analyses confirmed that PGC-1α dramatically affected the apoptosis-related genes in Ho-8910 cells. Mitochondrial functional assay showed that the induction of apoptosis was through the terminal stage by the release of cytochrome c. Furthermore, PG-C- 1 α-induced apoptosis was partially, but not completely, blocked by PPAR）, antagonist （GW9662）, and suppression of PPAR）, expression by siRNA also inhibited PGC-1α-induced apoptosis in Ho-8910 cells. These data suggested that PGC-1α exerted its effect through a PPARγ-dependent pathway. Our findings indicated that PGC-1α was involved in the apoptotic signal transduction pathways and downregulation of PGC-1α may be a key point in promoting epithelial ovarian cancer growth and progression.

Immunotherapy in human colorectal cancer: challenges and prospective

Human colorectal cancer(CRC) is the third most commonly diagnosed malignancies and the prognosis for patients with recurrent or metastatic disease is extremely poor. Although new chemotherapeutic regimen improves survival rates, therapy with better efficacy and less adverse effects is drastically needed. Immunotherapy has been investigated in human CRC for decades with limited success. However, recent developments of immunotherapy, particularly immune checkpoint inhibitor therapy, have achieved promising clinical benefits in many types of cancer and revived the hope for utilizing such therapy in human CRC. In this review, we will discuss important immunological landscape within the CRC microenvironment and introduce immunoscore system to better describe immunophenotyping in CRC. We will also discuss different immunotherapeutic approaches currently utilized in different phases of clinical trials. Some of those completed or ongoing trials are summarized. Finally, we provide a brief prospective on the future human CRC immunotherapy.

EGFR antisense RNA blocks expression of the epidermal growth factor receptor and partially reverse the malignant phenotype of human breast cancer MDA-MB-231 cells

The effects of human EGFR to the malignant phenotype of human breast cancer cell line MDA-MB-231 were investigated experimentally. A retroviral vector containing a 5'1350bp fragment of the human EGFR cDNA in the antisense orientation was transfected into targeted cells by lipofectamine. The effects on cell proliferation, cell cycle and adherent ability to extracellular matrix (ECM) components were studied after the expression of antisense transcripts to EGFR 5'1350bp fragment in target cells. In vitro studies showed that the growth ability of the transfected cells was partialy inhibited in comparison to parental cells and to cells transfected with the plasmid containing the neomycin resistance gene only. It was found that EGF (10ng/ml) had an augmenation effect on the growth of transfected MDA-AS10 cells but not MDA-MB-231 cells.Flow cytometric analysis showed that the cell cycle of the transfected cells was abnormal with a decrease of cells in G2/M and S phases and an increase of cells in G1 phase,indicating a blockage in phase G1. Immunofluorescence of EGFR expression in transfectants stained with an antiEGFR antibody was decreased and their growth in soft agarose was also severely impaired. The transfected cells showed less adherence to laminin (LN) and fibronectin (FN). In short, EGFR antisense RNA decreases the expression of EGFR on MDA-MB-231 cells and partially reverses their malignant phenotype as well.Effects of antisense EGFR on human breast cancer MDA-MB-231 cells

Anti-cancer effect of ethylacetate fraction from Orostachys japonicus on HT-29 human colon cancer cells by induction of apoptosis through caspase-dependent signaling pathway

Objective: To investigate the anti-colon cancer effects of ethylacetate fraction from Orostachys japonicus(0. japonicus) on HT-29 cancer cells. Methods: The viability of HT-29 cells was assayed by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2 H-tetrazolium(MTS) method. Apoptosis induction and cell cycle inhibition were confirmed by fluorescein isothiocyanate and propidium iodide staining using flow cytometry.Morphological changes in the nucleus were observed, using a fluorescence microscope with4',6-diamidino-2-phenylindole(DAPI) nuclear staining. The expression levels of the upstream and downstream proteins involved in the anti-cancer mechanism were confirmed by Western blotting. Results: After treating HT-29 cells with different concentrations of ethylacetate fraction from O. japonicus, the viability of cells decreased in a concentration-dependent manner,while apoptosis induction and apoptotic body formation increased. Cell cycle analysis showed that the arrest occurred at the sub-G_1 and S phase. Among the upstream and downstream proteins involved in anti-cancer activity, the level of B cell lymphoma-2 decreased, and the bcl-2-associated x protein increased. The level of pro-caspase-3, pro-caspase-8, and pro-caspase-9 decreased, while the level of cleaved-caspase-3, cleaved-caspase-8, and cleaved-caspase-9 increased. Moreover, the phosphorylation, that is, activation of extracellular signal regulated kinase 1/2, Jun-N-terminal kinase, and p38 increased. Conclusions: Combining the above results, it is thought that the survival of HT-29 cells is suppressed by ethylacetate fraction from0. japonicus through mitochondrial regulation-induced caspase cascade activation, induction of apoptosis and cell cycle arrest.