Colorectal Cancer: A Review of Carcinogenesis, Global Epidemiology, Current Challenges, Risk Factors, Preventive and Treatment Strategies

Colorectal cancer (CRC) is the second most deadly cancer. Global incidence and mortality are likely to be increased in the coming decades. Although the deaths associated with CRC are very high in high-income countries, the incidence and fatalities related to CRC are growing in developing countries too. CRC detected early is entirely curable by surgery and subsequent medications. However, the recurrence rate is high, and cancer drug resistance increases the treatment failure rate. Access to early diagnosis and treatment of CRC for survival is somewhat possible in developed countries. However, these facilities are rarely available in developing countries. Highlighting the current status of CRC, its development, risk factors, and management is crucial in creating public awareness. Therefore, in this review, we have comprehensively discussed the current global epidemiology, drug resistance, challenges, risk factors, and preventive and treatment strategies of CRC. Additionally, there is a brief discussion on the CRC development pathways and recommendations for preventing and treating CRC.

Micro- and Nanosecond Pulses Used in Doxorubicin Electrochemotherapy in Human Breast and Colon Cancer Cells with Drug Resistance

(1) Background: Pulsed electric field (PEF) techniques are commonly used to support the delivery of various molecules. A PEF seems a promising method for low permeability drugs or when cells demonstrate therapy resistance and the cell membrane becomes an impermeable barrier. (2) Methods: In this study, we have used doxorubicin-resistant and sensitive models of human breast cancer (MCF-7/DX, MCF-7/WT) and colon cancer cells (LoVo, LoVoDX). The study aimed to investigate the susceptibility of the cells to doxorubicin (DOX) and electric fields in the 20–900 ns pulse duration range. The viability assay was utilized to evaluate the PEF protocols’ efficacy. Cell confluency and reduced glutathione were measured after PEF protocols. (3) Results: The obtained results showed that PEFs significantly supported doxorubicin delivery and cytotoxicity after 48 and 72 h. The 60 kV/cm ultrashort pulses × 20 ns × 400 had the most significant cytotoxic anticancer effect. The increase in DOX concentration provokes a decrease in cell viability, affected cell confluency, and reduced GSSH when combined with the ESOPE (European Standard Operating Procedures of Electrochemotherapy) protocol. Additionally, reactive oxygen species after PEF and PEF-DOX were detected. (4) Conclusions: Ultrashort electric pulses with low DOX content or ESOPE with higher DOX content seem the most promising in colon and breast cancer treatment.

The regulation of autophagy by the miR-199a-5p/p62 axis was a potential mechanism of small cell lung cancer cisplatin resistance

BACKGROUND

Autophagy has been found to be involved in the multidrug resistance (MDR) of cancers, but whether it is associated with resistance of small cell lung cancer (SCLC) has not been studied. Here, we hypothesized that a potential autophagy-regulating miRNA, miR-199a-5p, regulated cisplatin-resistant SCLC.

METHODS

We validated the MDR of H446/EP using CCK-8 and LDH. We tested the binding of miR-199a-5p to p62 using the Dual-Luciferase assay and validated the association of miR-199a-5p and p62 in SCLC samples. We overexpressed (OE) and knocked down (KD) miR-199a-5p in H446 and H446/EP and determined the expression of miR-199a-5p, autophagy-related proteins, and the formation of autophagolysosomes using QPCR, western blotting, and MDC staining respectively. These results were validated in an orthotopic H446 mouse model of SCLC.

RESULTS

H446/EP was resistant to cisplatin, etoposide, paclitexal, epirubicin, irinotecan, and vinorelbine. Exposure of cisplatin at 5 μg/ml for 24 h increased LC3II/LC3I, ATG5, p62, and the formation of autophagolysosomes in H446 cells, but not in H446/EP cells. The expression of miR-199a-5p was up-regulated in H446/EP compared to H446. MiR-199a-5p directly targeted the p62 gene. The expression of miR-199a-5p and p62 were correlated in SCLC samples. In H446 and H69PR, the OE of miR-199a-5p increased LC3II/LC3I, p62, and the formation of autophagolysosomes, but not ATG5, while the KD of miR-199a-5p decreased p62, but did not affect LC3II/LC3I, ATG5, and the formation of autophagolysosomes. In H446/EP, the OE of miR-199a-5p decreased p62 only. These results were generally consistent to results in the animal tumor samples.

CONCLUSIONS

The regulation of autophagy by the miR-199a-5p/p62 axis was a potential mechanism of small cell lung cancer cisplatin resistance.

Comparative Proteomics Analysis Reveals the Reversal Effect of Cryptotanshinone on Gefitinib-Resistant Cells in Epidermal Growth Factor Receptor-Mutant Lung Cancer

Cryptotanshinone (CTS) is a lipophilic constituent of Salvia miltiorrhiza, with a broad-spectrum anticancer activity. We have observed that CTS enhances the efficacy of gefitinib in human lung cancer H1975 cells, yet little is known about its molecular mechanism. To explore how CTS enhances H1975 cell sensitivity to gefitinib, we figured out differential proteins of H1975 cells treated by gefitinib alone or in combination with CTS using label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS). Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and protein–protein interaction (PPI) bioinformatic analyses of the differential proteins were performed. CTS enhanced H1975 cell sensitivity to gefitinib in vitro and in vivo, with 115 and 128 differential proteins identified, respectively. GO enrichment, KEGG analysis, and PPI network comprehensively demonstrated that CTS mainly impacted the redox process and fatty acid metabolism in H1975 cells. Moreover, three differential proteins, namely, catalase (CAT), heme oxygenase 1 (HMOX1), and stearoyl-CoA desaturase (SCD) were validated by RT-qPCR and Western blot. In conclusion, we used a proteomic method to study the mechanism of CTS enhancing gefitinib sensitivity in H1975 cells. Our finding reveals the potential protein targets of CTS in overcoming gefitinib resistance, which may be therapeutical targets in lung cancer.

Identification of key regulators associated with colon cancer prognosis and pathogenesis

Colon cancer (CC) is the fourth deadliest cancer in the world. New insights into prognostication might be helpful to define the optimal adjuvant treatments for patients in routine clinical practice. Here, a microarray dataset with 30 primary tumors and 30 normal samples was analyzed using GEO2R to find differentially expressed genes (DEGs). Then, DAVID, KEGG, ChEA and X2K were used to analyze DEGs-related Gene Ontology, pathways, transcription factors (TFs) and kinases, respectively. Protein-protein interaction (PPI) networks were constructed using the STRING database and Cytoscape. The modules and hub genes of DEGs was determined through MCODE and CytoHubba plugins, and the expression of hub genes was verified using GEPIA. To find microRNAs and metabolites associated with DEGs, miRTarBase and HMDB were used, respectively. It was found that 233 and 373 genes were upregulated and downregulated in CC, respectively. GO analysis showed that the upregulated DEGs were mainly involved in mitotic nuclear division and cell division. Top 10 hub genes were identified, including AURKB, CDK1, DLGAP5, AURKA, CCNB2, CCNB1, BUB1B, CCNA2, KIF20A and BUB1. Whereas, FOMX1, E2F7, E2F1, E2F4 and AR were identified as top 5 TFs in CC. Moreover, CDK1, CDC2, MAPK14, ATM and CK2ALPHA was identified as top 5 kinases in CC. miRNAs analysis showed that Hsa-miR-215-5p hsa-miR-193b-3p, hsa-miR-192-5p and hsa-miR-16-5p could target the largest number of CC genes. Taken together, CC-related genes, especially the hub genes, TFs, and metabolites might be used as novel biomarkers for CC, as well as for diagnosis and guiding therapeutic strategies for CC.

Caspase-Mediated Cleavage of the Transcription Factor Sp3: Possible Relevance to Cancer and the Lytic Cycle of Kaposi's Sarcoma-Associated Herpesvirus

The open reading frame 50 (ORF50) protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is the master regulator essential for initiating the viral lytic cycle. Previously, we have demonstrated that the ORF50 protein can cooperate with Sp3 to synergistically activate a set of viral and cellular gene promoters through highly conserved ORF50-responsive elements that harbor a Sp3-binding motif. Herein, we show that Sp3 undergoes proteolytic cleavage during the viral lytic cycle, and the cleavage of Sp3 is dependent on caspase activation. Since similar cleavage patterns of Sp3 could be detected in both KSHV-positive and KSHV-negative lymphoma cells undergoing apoptosis, the proteolytic cleavage of Sp3 could be a common event during apoptosis. Mutational analysis identifies 12 caspase cleavage sites in Sp3, which are situated at the aspartate (D) positions D17, D19, D180, D273, D275, D293, D304 (or D307), D326, D344, D530, D543, and D565. Importantly, we noticed that three stable Sp3 C-terminal fragments generated through cleavage at D530, D543, or D565 encompass an intact DNA-binding domain. Like the full-length Sp3, the C-terminal fragments of Sp3 could still retain the ability to cooperate with ORF50 protein to activate specific viral and cellular gene promoters synergistically. Collectively, our findings suggest that despite the proteolytic cleavage of Sp3 under apoptotic conditions, the resultant Sp3 fragments may retain biological activities important for the viral lytic cycle or for cellular apoptosis. IMPORTANCE The ORF50 protein of Kaposi's sarcoma-associated herpesvirus (KSHV) is the key viral protein that controls the switch from latency to lytic reactivation. It is a potent transactivator that can activate target gene promoters via interacting with other cellular DNA-binding transcription factors, such as Sp3. In this report, we show that Sp3 is proteolytically cleaved during the viral lytic cycle, and up to 12 caspase cleavage sites are identified in Sp3. Despite the proteolytic cleavage of Sp3, several resulting C-terminal fragments that have intact zinc-finger DNA-binding domains still retain substantial influence in the synergy with ORF50 to activate specific gene promoters. Overall, our studies elucidate the caspase-mediated cleavage of Sp3 and uncover how ORF50 utilizes the cleavage fragments of Sp3 to transactivate specific viral and cellular gene promoters.

Dihydrotanshinone I inhibits ovarian tumor growth by activating oxidative stress through Keap1-mediated Nrf2 ubiquitination degradation

Dihydrotanshinone I (DHT), a bioactive compound in Salvia miltiorrhiza, was reported to exhibit cytotoxicity against various malignancies. However, the underlying mechanism on ovarian cancer remains unclear. Here, DHT inhibited cell viability of ovarian cancer HO8910PM, SKOV3, A2780 and ES2 cells. It showed moderate inhibitory effect on ovarian epithelial IOSE80 cells and lower toxicity than chemotherapy drugs. DHT induced apoptosis and G2 cell cycle arrest accompanied by reduced expression of Bcl-2, Caspase-3, and increased Bax. Meanwhile, DHT increased ROS accumulation, decreased mitochondrial membrane potential and activated oxidative stress in HO8910PM and ES2 cells. Mechanistically, DHT inhibited Nrf2 and p62 expression, Nrf2 target genes and enzymes, and Nrf2 nuclear translocation, while increased the expression of Nrf2 inhibitor Keap1. NAC, a ROS scavenger, rescued DHT-induced proliferation inhibition, ROS generation and Nrf2 inhibition. DHT alleviated tBHQ-induced Nrf2 expression and increased its mRNA level. However, the proteasome inhibitor MG132 blocked DHT-induced Nrf2 inhibition, suggesting a post-translational regulation manner. DHT enhanced Nrf2 binding with Keap1, leading to potentiated Nrf2 ubiquitination degradation. Furthermore, Nrf2 and p62 overexpression blocked DHT-induced Nrf2 and p62 inhibition. Consistent with the in vitro results, DHT significantly delayed tumor growth in HO8910PM and ES2 xenograft nude mice, decreased tumor marker HE4 and CA125 levels, reversed the abnormally expressed proteins including Ki67, Nrf2, p62, Keap1, Bcl-2, CyclinB1, Cdc-2, and antioxidant enzymes SOD, CAT in vivo. Serum from DHT-treated mice also inhibited cell growth in vitro. Taken together, DHT exhibits anti-ovarian tumor effect by activating oxidative stress through ubiquitination-mediated Nrf2 degradation. Our findings implicate a potential application of DHT for ovarian cancer therapy.

Integrated Chromatin Accessibility and Transcriptome Landscapes of 5-Fluorouracil-Resistant Colon Cancer Cells

Background: 5-Fluorouracil (5-FU) is one of the most effective and widely used chemotherapeutic drugs in the treatment of colon cancer, yet chemoresistance is a common feature of colon cancer treatment, resulting in poor prognosis and short survival. Dynamic reprogramming of chromatin accessibility is crucial for proper regulation of gene transcription associated with cancer drug resistance by providing the gene regulatory machinery with rapid access to the open genomic DNA.

Methods: Here, we explored the global chromatin accessibility and transcription changes by the assay for transposase-accessible chromatin using sequencing (ATAC-seq) in combination with transcriptome sequencing of both parental and 5-FU-resistant HCT15 cells, followed by integrative analysis to better understand the regulatory network underlying 5-FU resistance in colon cancer cells.

Results: A total of 3,175 differentially expressed mRNAs (DEGs), lncRNAs (DELs), and miRNAs (DEMs) related to 5-FU resistance were identified, including significantly upregulated IL33, H19, and miR-17-5p; the downregulated AKR1B10, LINC01012, and miR-125b-5p; and chromatin modifiers such as INO80C, HDAC6, and KDM5A. The construction of the ceRNA regulatory network revealed that H19, HOXA11-AS, and NEAT1 might function as ceRNAs associated with 5-FU resistance in HCT15 cells. Moreover, 9,868 differentially accessible regions (DARs) were obtained, which were positively (r = 0.58) correlated with their nearest DEGs and DELs. The upregulated genes related to 4,937 hyper-accessible regions were significantly enriched in signaling pathways of MAPK, FOX, and WNT, while the 4,931 hypo-accessible regions were considered to be involved in declined biosynthesis of amino acids and nucleotide sugars, signaling pathways of Notch, and HIF-1. Analyses of the DAR sequences revealed that besides the AP-1 family, the TF motifs of FOX and KLF family members were highly enriched in hyper- and hypo-accessible regions, respectively. Finally, we obtained several critical TFs and their potential targets associated with DARs and 5-FU resistance, including FOXA1 and KLF3.

Conclusion: These data provided clear insights and valuable resources for an improved understanding of the non-genetic landscape of 5-FU-resistant colon cancer cells based on chromatin accessibility and transcript levels, which allowed for genome-wide detection of TF binding sites, potential cis-regulatory elements and therapeutic targets.

Therapeutic approach for digestive system cancers and potential implications of exercise under hypoxia condition: what little is known? a narrative review

BACKGROUND

Cancer, like other chronic pathologies, is associated with the presence of hypoxic regions due to the uncontrolled cell growth. Under this pathological hypoxic condition, various molecular signaling pathways are activated to ensure cell survival, such as those that govern angiogenesis, erythropoiesis, among others. These molecular processes are very similar to the physiological response caused by exposure to altitude (natural hypobaric systemic hypoxia), the use of artificial hypoxia devices (systemic normobaric simulated hypoxia) or the delivery of vascular occlusion to the extremities (also called local hypoxia by the blood flow restriction technique). "Tumor hypoxia" has gained further clinical importance due to its crucial role in both tumor progression and resistance to treatment. However, the ability to manipulate this pathway through physical exercise and systemic hypoxia-mediated signaling pathways could offer an important range of therapeutic opportunities that should be further investigated.

METHODS

This review is focused on the potential implications of systemic hypoxia combined with exercise in digestive system neoplasms prognosis. Articles included in the review were retrieved by searching among the three main scientific databases: PubMed, Scopus, and Embase.

FINDINGS

The findings of this review suggest that exercise performed under systemic hypoxic conditions could have a positive impact in prognosis and quality of life of the population with digestive system cancers.

CONCLUSIONS

Further studies are needed to consider this paradigm as a new potential intervention in digestive oncological population.

Recent Progress of Novel Nanotechnology Challenging the Multidrug Resistance of Cancer

Multidrug resistance (MDR) of tumors is one of the clinical direct reasons for chemotherapy failure. MDR directly leads to tumor recurrence and metastasis, with extremely grievous mortality. Engineering a novel nano-delivery system for the treatment of MDR tumors has become an important part of nanotechnology. Herein, this review will take those different mechanisms of MDR as the classification standards and systematically summarize the advances in nanotechnology targeting different mechanisms of MDR in recent years. However, it still needs to be seriously considered that there are still some thorny problems in the application of the nano-delivery system against MDR tumors, including the excessive utilization of carrier materials, low drug-loading capacity, relatively narrow targeting mechanism, and so on. It is hoped that through the continuous development of nanotechnology, nano-delivery systems with more universal uses and a simpler preparation process can be obtained, for achieving the goal of defeating cancer MDR and accelerating clinical transformation.

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.

S-20, a steroidal saponin from the berries of black nightshade, exerts anti-multidrug resistance activity in K562/ADR cells through autophagic cell death and ERK activation

Multidrug resistance (MDR) is a major cause of chemotherapy failure. Adriamycin (ADR) has been widely used to treat cancer, however, as a substrate of the adenosine triphosphate binding cassette (ABC) transporter, it is easy to develop drug resistance during the treatment. Here, we demonstrated that steroidal saponin S-20 isolated from the berries of black nightshade has comparable cytotoxicity in ADR-sensitive and resistant K562 cell lines. Autophagy is generally considered to be a protective mechanism to mediate MDR during treatment. However, we found that S-20-induced cell death in K562/ADR is associated with autophagy. We further explored the underlying mechanisms and found that S-20 induces caspase-dependent apoptosis in ADR-sensitive and resistant K562 cell lines. Most importantly, S-20-induced autophagy activates the ERK pathway and then inhibits the expression of drug resistance protein, which is the main reason to overcome K562/ADR resistance, rather than apoptosis. Taken together, our findings emphasize that S-20 exerts anti-multidrug resistance activity in K562/ADR cells through autophagic cell death and ERK activation, which may be considered as an effective strategy.

Inoscavin A, a pyrone compound isolated from a Sanghuangporus vaninii extract, inhibits colon cancer cell growth and induces cell apoptosis via the hedgehog signaling pathway

BACKGROUND

Sanghuangporus vaninii, a large precious medicinal fungus called Sanghuang in China, has significant antitumor activity. We previously reported that a Sanghuangporus vaninii extract could lead to apoptosis in HT-29 cells through the intrinsic apoptotic pathway. We further found that Inoscavin A exhibited anti-colon cancer activity, but its specific mechanisms have not been fully elucidated.

METHODS

Inoscavin A was obtained from Sanghuangporus vaninii by the classic phytochemical separation technology. The male BALB/c nude mice were injected with HT-29 colon cancer cells as animal model. In order to observe the pathological changes of tumor section, the hematoxylin-eosin(H&E) staining was applied in the histological analysis. Metabolomics was utilized for the investigation of the overall changes of serum metabolites in animal model, and the potential targets of Inoscavin A were analyzed by Ingenuity Pathway Analysis (IPA). We further employed a molecular docking approach to predict the degree of combination of Inoscavin A and Smo. Then we further performed Western blotting and immunofluorescence analysis to investigate the expression of proteins involved in Hh-related pathways in tumor tissues. In addition, the colony formation assay, scratch-wound assay and transwell migration and invasion assay were conducted to evaluate the anti-colon-cancer activity of Inoscavin A. Concurrently, the mitochondrial membrane potential assay and TUNEL apoptosis assay were detected to demonstrate the effect of Inoscavin A on promoting HT-29 cells apoptosis. Western blot experiments verified the anti-tumor effects of Inoscavin A were modulated the protein expression of Shh, Ptch1, Smo and Gli1 in HT-29 cells.

RESULTS

We showed that Inoscavin A, a pyrone compound isolated from the Sanghuangporus vaninii extract, exerted its antitumor activity in an HT-29 colon cancer cell xenograft mouse model. Subsequently, we first time prove that the antitumor effects of Inoscavin A were related to the hedgehog (Hh) signaling pathway. Furthermore, we demonstrated that Smo, the core receptor of the Hh pathway, was critical for the induction of apoptosis of Inoscavin A and that overexpression of this target could significantly rescue cell apoptosis induced by Inoscavin A treatment.

CONCLUSION

Thus, our studies first propose that the natural outgrowth Inoscavin A exerted its anti-cancer effects by inhibiting Smo to suppress the activity of the Hh pathway though inhibiting cell proliferation and promoting apoptosis. These findings further indicate that Inoscavin A will be expected to be a prospective remedical compound for the treatment of colon cancer.

5mC-Related lncRNAs as Potential Prognostic Biomarkers in Colon Adenocarcinoma

Simple Summary

To identify the prognostic significance of 5mC-related lncRNAs in colon adenocarcinoma (COAD), we examined the expression levels and mutations of 21 5mC-regulated genes of COAD in TCGA. We also identified lncRNAs associated with 5mC regulatory genes using Pearson correlation analysis. After the least absolute shrinkage and selection operator (Lasso) Cox regression, the risk signature of 4 5mC-related lncRNAs was selected. Next, the risk signature’s predictive efficacy was proven. Moreover, the biological mechanism and potential immunotherapeutic response of this risk signature were identified. Collectively, we constructed the 5mC-related lncRNA risk signature, which could provide a novel prognostic prediction of COAD patients.

Abstract

Globally, colon adenocarcinoma (COAD) is one of the most frequent types of malignant tumors. About 40~50% of patients with advanced colon adenocarcinoma die from recurrence and metastasis. Long non-coding RNAs (lncRNAs) and 5-methylcytosine (5mC) regulatory genes have been demonstrated to involve in the progression and prognosis of COAD. The goal of this study was to explore the biological characteristics and potential predictive value of 5mC-related lncRNA signature in COAD. In this research, The Cancer Genome Atlas (TCGA) was utilized to obtain the expression of genes and somatic mutations in COAD, and Pearson correlation analysis was used to select lncRNAs involved in 5mC-regulated genes. Furthermore, we applied univariate Cox regression and Lasso Cox regression to construct 5mC-related lncRNA signature. Then Kaplan–Meier survival analysis, principal components analysis (PCA), receiver operating characteristic (ROC) curve, and a nomogram were performed to estimate the prognostic effect of the risk signature. GSEA was utilized to predict downstream access of the risk signature. Finally, the immune characteristics and immunotherapeutic signatures targeting this risk signature were analyzed. In the results, we obtained 1652 5mC-related lncRNAs by Pearson correlation analysis in the TCGA database. Next, we selected a risk signature that comprised 4 5mC-related lncRNAs by univariate and Lasso Cox regression. The prognostic value of the risk signature was proven. Finally, the biological mechanism and potential immunotherapeutic response of the risk signature were identified. Collectively, we constructed the 5mC-related lncRNA risk signature, which could provide a novel prognostic prediction of COAD patients.

Research Progress and Prospects of Autophagy in the Mechanism of Multidrug Resistance in Tumors

Although the treatment of cancer has made great strides in clinical practice, its high morbidity and fatality rates remain a major threat to human health. Multidrug resistance (MDR) often appears in the process of tumor treatment, leading to tumor refractory and aggravating the risk of tumor recurrence. Therefore, antitumor MDR plays a key role in tumor chemotherapy. Autophagy is an important process for the turnover of intracellular materials, which is commonly seen in the treatment of sensitive and multidrug-resistant tumors, and it can play different roles in various types of MDR tumor cells and tissues. Autophagy plays a dual regulatory role in MDR tumors. On the one hand, autophagy can promote the formation of MDR in tumor cells, weaken the killing effect of chemotherapy drugs on tumor cells, and play a protective role in tumor survival. On the other hand, autophagy production in the cellular environment can kill MDR tumor cells, reverse tumor resistance and enhance the efficiency of chemotherapy drugs. Therefore, the regulation of autophagy to overcome MDR has become increasingly significant in tumor chemotherapy. In this article, we discussed and summarized the research progress of autophagy in MDR tumors, mainly involving the different characteristics of autophagy in MDR cancer cells.

miR‑146b‑5p promotes colorectal cancer progression by targeting TRAF6

Increasing evidence highlights the multiple roles of microRNAs (miRs) in the tumorigenesis of colorectal cancer (CRC); however, the molecular mechanism, particularly the target of miR-146b-5p in CRC has not been fully elucidated. The present study aimed to elucidate the influence of miR-146b-5p via regulating tumor necrosis factor receptor-associated factor 6 (TRAF6) in CRC. The expression levels of miR-146b-5p and TRAF6 in CRC tissue and cells were determined by reverse transcription quantitative PCR and western blotting. Binding between miR-146b-5p and TRAF6 was examined using a dual luciferase reporter gene assay. The impact of miR-146b-5p and TRAF6 on proliferation and migration of CRC cells was determined using Cell Counting Kit-8 and Transwell assays, respectively. An animal model of CRC was established to determine the carcinogenic effect of the miR-146b-5p-TRAF6 axis. The results demonstrated that miR-146b-5p was highly expressed in CRC tissue samples compared with in normal adjacent tissue samples and in CRC cells compared with in the normal NCM460 cell line, whereas TRAF6 was expressed at low levels. Overexpression of miR-146b-5p decreased TRAF6 expression in CRC HT29 and SW620 cells. miR-146b-5p targeted and inhibited TRAF6 expression in CRC cells. Furthermore, transfection with a miR-146b-5p mimic promoted the proliferation, migration and invasion of CRC cells and tumor growth; however, these effects were abolished by TRAF6 overexpression. Transfection with a miR-146b-5p inhibitor suppressed the proliferation of CRC cells. Taken together, the results from the present study demonstrated that miR-146b-5p could enhance the initiation and tumorigenesis of CRC by targeting TRAF6. These results will help elucidate the mechanisms underlying CRC development and will facilitate the development of targeted therapy for CRC.

Comparative Study between Curcumin and Nanocurcumin Loaded PLGA on Colon Carcinogenesis Induced Mice

Colorectal cancer is the third most common cancer. Because curcumin (CUR) has anti-inflammatory and anticancer properties, research has been undertaken to indicate that nanocurcumin compounds can be used to treat a variety of cancers. CUR in nanoform has been found to have a stronger effect than conventional CUR. The purpose of this study was to show that CUR-loaded poly lactic-co-glycolic acid nanoparticles (PLGA) (CUR-loaded PLGA) have anti-inflammatory and anticancer effects on colon carcinogenesis in male dimethyl hydrazine (DMH) mice as a comparative study between the nanoform of curcumin and normal curcumin, focusing on the anticancer effect of nanocurcumin. Mice were separated into six groups: No treatment was given to Group I (negative Group-I). Group II was treated with CUR. Group III was treated with CUR-loaded PLGA. Group IV was treated with DMH. Group V received DMH and curcumin. Group VI received DMH and CUR-loaded PLGA. At the conclusion of the trial, the animals were slain (6 weeks). Inflammatory indicators and vascular endothelial growth factor (VEGF) levels all changed significantly in this study, as the following inflammatory markers as TNF showed percent of change compared to the DMH group. Recovery percentage for Groups V and VI, respectively, were 9.18 and 55.31%. In addition, IL1 was 7.45 and 50.37% for Groups V and VI, respectively. The results of IL6 were 4.86 and 25.79% for Groups V and VI, respectively. The vascular endothelial growth factor (VEGF) recovery percent was 16.98 and 45.12% for Groups V and VI, respectively. Following the effect of DMH on colon mucosa shape, the researchers looked at the effect of CUR-loaded PLGA on colon histology. It was shown that CUR-loaded PLGA affects the cell cycle and PCNA expression. We conclude that nanocurcumin is an important anti-inflammatory and cancer-fighting agent.

Allium cepa: A Treasure of Bioactive Phytochemicals with Prospective Health Benefits

As Allium cepa is one of the most important condiment plants grown and consumed all over the world, various therapeutic and pharmacological effects of A. cepa were reviewed. Onion (Allium cepa) is a high dietary fiber-rich perennial herb that is placed under the family Amaryllidaceae. It contains high concentration of folic acid, vitamin B6, magnesium, calcium, potassium, and phosphorus as well as vitamins and minerals. It is widely used as an antimicrobial agent, but it showed anticancer, antidiabetic, antioxidant, antiplatelet, antihypertensive, and antidepressant effects and neuroprotective, anti-inflammatory, and antiparasitic effects and so on. It is said to have beneficial effects on the digestive, circulatory, and respiratory systems, as well as on the immune system. This review article was devoted to discussing many health benefits and traditional uses of onions in pharmacological perspectives, as well as the safety/toxicological profile. If more detailed research on this perennial herb is conducted, it will open the door to an infinite number of possibilities.

Construction and Validation of a Combined Ferroptosis and Hypoxia Prognostic Signature for Hepatocellular Carcinoma

Background: Ferroptosis, as a unique programmed cell death modality, has been found to be closely related to the occurrence and development of hepatocellular carcinoma (HCC). Hypoxia signaling pathway has been found to be extensively involved in the transformation and growth of HCC and to inhibit anti-tumor therapy through various approaches. However, there is no high-throughput study to explore the potential link between ferroptosis and hypoxia, as well as their combined effect on the prognosis of HCC.

Methods: We included 370 patients in The Cancer Genome Atlas (TCGA) database and 231 patients in the International Cancer Genome Consortium (ICGC) database. Univariate COX regression and Least Absolute Shrinkage and Selection Operator approach were used to construct ferroptosis-related genes (FRGs) and hypoxia-related genes (HRGs) prognostic signature (FHPS). Kaplan–Meier method and Receiver Operating Characteristic curves were analyzed to evaluate the predictive capability of FHPS. CIBERSOR and single-sample Gene Set Enrichment Analysis were used to explore the connection between FHPS and tumor immune microenvironment. Immunohistochemical staining was used to compare the protein expression of prognostic FRGs and HRGs between normal liver tissue and HCC tissue. In addition, the nomogram was established to facilitate the clinical application of FHPS.

Results: Ten FRGs and HRGs were used to establish the FHPS. We found consistent results in the TCGA training cohort, as well as in the independent ICGC validation cohort, that patients in the high-FHPS subgroup had advanced tumor staging, shorter survival time, and higher mortality. Moreover, patients in the high-FHPS subgroup showed ferroptosis suppressive, high hypoxia, and immunosuppression status. Finally, the nomogram showed a strong prognostic capability to predict overall survival (OS) for HCC patients.

Conclusion: We developed a novel prognostic signature combining ferroptosis and hypoxia to predict OS, ferroptosis, hypoxia, and immune status, which provides a new idea for individualized treatment of HCC patients.

Mefenamic acid as a promising therapeutic medicine against colon cancer in tumor-bearing mice

Although radiotherapy is an effective strategy for cancer treatment, tumor resistance to ionizing radiation (IR) and its toxic effects on normal tissues are limiting its use. The aim of this study is to evaluate the anti-cancer effects of mefenamic acid (MEF), as an approved medicine, and its combination with IR against colon tumor cells in mice. Tumor-bearing mice were received MEF at a dose of 25 mg/kg for 6 successive days. The tumor size was measured. In the second experiment, after MEF treatment, tumor-bearing mice locally received an X-ray at dose 6 Gy. Tumor growth and biochemical, histological, and immunohistological assay (caspase-3) were performed. MEF significantly decreased tumor size in mice in comparison to the control group. IR and/or MEF treatment significantly reduced the tumor volume and inhibited tumor growth by 49%, 55%, and 67% by MEF, IR, and MEF + IR groups as compared with the control group. Administration of MEF in combination with radiation had a synergistic effect on enhanced histopathological changes in tumor tissues. MEF treatment in IR exposure mice showed a significant increase in the immunoreactivity of caspase-3 in the colon tumor tissue. MEF has an anti-tumor effect in colon tumor-bearing mice. MEF in combination with IR increased pathological changes and apoptosis in tumor tissues, suggesting that MEF might be clinically useful in the treatment of colon cancer.

Clinical significance of circulating tumor cells in predicating the outcomes of patients with colorectal cancer

BACKGROUND

Relapse and metastasis of patients with Colorectal Cancer (CRC) is the major obstacle to the long-term life of patients. Its mechanisms remain defined.

METHODS

A total of 48 CRC patients were enrolled and 68 samples were obtained from the peripheral blood of patients before or after treatments in this study. Twenty non-cancer patients were also detected as a negative control. Circulating Tumor Cells (CTCs), including Epithelial CTCs (eCTCs), Mesenchymal (MCTCs), and epithelial/mesenchymal mixed phenotypes (mixed CTCs), were identified by CanPatrol^TM CTC enrichment and RNA in situ hybridization. The relationship between CTCs number and Progression-Free Survival (PFS) or Overall Survival (OS) was evaluated.

RESULTS

Thirty-four of 48 patients (70.8%) were found to have positive CTCs. Total CTCs and MCTCs in the post-treatment had a significant correlation PFS and OS. When total CTCs or MCTCs in 5 mL blood of patients were more than 6 CTCs or 5 MCTCs, PFS of the patients was significantly shorter (p < 0.05) than that in patients with less than 6 CTCs or 5 MCTCs. The patients with > 5 CTCs count changes were found to exhibit poor PFS and OS rates (p < 0.05).

CONCLUSION

Total CTCs and MCTCs number detection in patients with colorectal cancer was very useful biomarker for predicting the prognosis of patients. Higher CTCs or MCTCs had poorer PFS and OS rates.

Combination therapy with Nab-paclitaxel and the interleukin-15 fused with anti-human serum albumin nanobody as a synergistic treatment for colorectal cancer

This study determines the effect of Nab-paclitaxel in combination with IL-15 fusion protein, containing IL-15 and an anti-HSA nanobody domain, on colorectal cancer bearing mice. In vitro binding test of IL15 fusion protein to HSA and Nab-paclitaxel, as well as CTLL-2 cell stimulation assay were performed. The tumor inhibitory effects of Nab-paclitaxel in combination with IL-15 fusion protein was evaluated in the HCT116 bearing murine model. Moreover, the population and function of cytotoxic T cells and M1 macrophages, as well as MDSCs and Treg cells, were also further examined. As a result, combination therapy of Nab-paclitaxel and IL-15 fusion protein effectively inhibits the tumor growth and produced a 78% reduction in tumor size for HCT116, as compared to vehicle group. In the TDLN for the combination group, there were 18% of CD8+ IFN-γ + T-cells and 0.47% CD4⁺CD25⁺FOXP3⁺ regulatory T-cells, as opposed to 5.0% and 5.1%, respectively, for the model control group. Combination therapy further exhibited enhanced suppressive effects on the accumulation of CD11b⁺GR-1⁺ MDSC in spleen and bone marrow. Furthermore, Nab-paclitaxel and IL-15 fusion protein showed a significant suppression of NF-κB-mediated immune suppressive markers and increased expression of CD8, Granzyme B, CD62L, CD49b, and CD86 without obvious organ toxicity. In conclusion, combination therapy of Nab-paclitaxel and IL-15 fusion protein can effectively stimulate the antitumor activity of immune effector cells, thereby inhibiting immunosuppressive cells within the TME of colorectal cancer, and the overall therapeutic effect has a significant advantage over monotherapy.AbbreviationsInterleukin 15, IL-15; Human serum albumin, HSA; Myeloid-derived suppressor cells, MDSC; Albumin binding domain, ABD; Tumor drainage lymph node, TDLN; Natural killer (NK); Tumor-draining lymph node (TDLN); Tumor infiltrating lymphocyte, TIL; Immunogenic cell death, ICD; Enhanced permeability retention, EPR; Liposomal doxorubicin, Doxil; 5-fluorouracil, 5-FU.

Identification of a basement membrane-related gene signature for predicting prognosis and estimating the tumor immune microenvironment in breast cancer

INTRODUCTION

Breast cancer (BC) is the most common malignancy in the world and has a high cancer-related mortality rate. Basement membranes (BMs) guide cell polarity, differentiation, migration and survival, and their functions are closely related to tumor diseases. However, few studies have focused on the association of basement membrane-related genes (BMRGs) with BC. This study aimed to explore the prognostic features of BMRGs in BC and provide new directions for the prevention and treatment of BC.

METHODS

We collected transcriptomic and clinical data of BC patients from TCGA and GEO datasets and constructed a predictive signature for BMRGs by using univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis. The reliability of the model was further evaluated and validated by Kaplan-Meier survival curves and receiver operating characteristic curves (ROC). Column line plots and corresponding calibration curves were constructed. Possible biological pathways were investigated by enrichment analysis. Afterward, we assessed the mutation status by tumor mutational burden (TMB) analysis and compared different subtypes using cluster analysis. Finally, we examined drug treatment sensitivity and immunological correlation to lay the groundwork for more in-depth studies in this area.

RESULTS

The prognostic risk model consisted of 7 genes (FBLN5, ITGB2, LAMC3, MMP1, EVA1B, SDC1, UNC5A). After validation, we found that the model was highly reliable and could accurately predict the prognosis of BC patients. Cluster analysis showed that patients with cluster 1 had more sensitive drugs and had better chances of better clinical outcomes. In addition, TMB, immune checkpoint, immune status, and semi-inhibitory concentrations were significantly different between high and low-risk groups, with lower-risk patients having the better anti-cancer ability.

DISCUSSION

The basement membrane-related gene signature that we established can be applied as an independent prognostic factor for BC and can provide a reference for individualized treatment of BC patients.

Noncoding RNAs in triple negative breast cancer: Mechanisms for chemoresistance

Triple-negative breast cancer (TNBC) is the most aggressive subtype among breast cancers with high recurrence and this condition is partly due to chemoresistance. Therefore, fully understanding the mechanism of TNBC-resistance is the key to overcoming chemoresistance, which will be an effective strategy for TNBC therapy. Various potential mechanisms involved in the chemoresistance of TNBC have been investigated and indicated that noncoding RNAs (ncRNAs) especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) take part in most TNBC resistance. The ncRNA-induced chemoresistance process is involved in the alteration of many activities. here, we mainly summarize the mechanisms of ncRNAs in the chemoresistance of TNBC and discuss the potential clinical application of ncRNAs in the treatment of TNBC, indicating that targeting ncRNAs might be a promising strategy for resensitization to chemotherapies.

Overcoming multidrug resistance by knockout of ABCB1 gene using CRISPR/Cas9 system in SW620/Ad300 colorectal cancer cells

Multidrug resistance (MDR) has been extensively reported in colorectal cancer patients, which remains a major cause of chemotherapy failure. One of the critical mechanisms of MDR in colorectal cancer is the reduced intracellular drug level led by the upregulated expression of the ATP-binding cassette (ABC) transporters, particularly, ABCB1/P-gp. In this study, the CRISPR/Cas9 system was utilized to target ABCB1 in MDR colorectal cancer SW620/Ad300 cell line with ABCB1 overexpression. The results showed that stable knockout of ABCB1 gene by the CRISPR/Cas9 system was achieved in the MDR cancer cells. Reversal of MDR against ABCB1 chemotherapeutic drugs increased intracellular accumulation of [3H]-paclitaxel accumulation, and decreased drug efflux activity was observed in MDR SW620/Ad300 cells after ABCB1 gene knockout. Further tests using the 3D multicellular tumor spheroid model suggested that deficiency in ABCB1 restrained tumor spheroid growth and restore sensitivity to paclitaxel in MDR tumor spheroids. Overall, the CRISPR/Cas9 system targeting the ABCB1 gene can be an effective approach to overcome ABCB1-mediated MDR in colorectal cancer SW620/Ad300 cells.

Cryptotanshinone enhances the efficacy of Bcr-Abl tyrosine kinase inhibitors via inhibiting STAT3 and eIF4E signalling pathways in chronic myeloid leukaemia

CONTEXT

A portion of patients with chronic myeloid leukaemia (CML) develop resistance to the Bcr-Abl tyrosine kinase inhibitors (TKIs), limiting the clinical applications. Previous results have demonstrated the synergistic effects between cryptotanshinone (CPT) and imatinib on apoptosis of CML cells in vitro.

OBJECTIVE

To determine the antileukemia effects of CPT and TKIs on the resistant CML cells, and further investigate the effect of combined treatment of CPT and imatinib on tumour growth and apoptosis in the xenograft model and clarify its regulatory mechanisms.

MATERIALS AND METHODS

The combination effects of CPT and second-generation TKIs were evaluated in resistant CML cells K562-R. CPT and imatinib were orally administered once daily for 21 days on K562-R xenografts in nude mice (6 per group). Tumour proliferation and apoptosis were examined by Ki-67, PCNA and TUNEL staining. The expression levels of apoptotic markers and activities of STAT3 and eIF4E pathways were determined via immunohistochemistry staining and western blotting analysis.

RESULTS

CPT significantly enhanced the antiproliferative effects of TKIs, via triggering cleavages of caspase proteins, and inhibiting activities of STAT3 and eIF4E pathways. The administration of CPT and imatinib dramatically inhibited the tumour growth of xenografts and achieved a suppression of 60.2%, which is 2.6-fold higher than that of single imatinib group. Furthermore, CPT and imatinib increased the apoptotic rates and markedly decreased the phosphorylation levels of STAT3 and eIF4E.

CONCLUSIONS

Our results demonstrated that CPT could significantly enhance the antileukemia efficacy of TKIs, suggesting the therapeutic potential of CPT to overcome CML resistance.

Identification of AGT and CD44 in methotrexate-resistant colorectal cancer and reversal of methotrexate-resistance

This study aims to screen out hub genes in 2 methotrexate-resistant colorectal cancer (CRC) cells (HT29 and Caco2), compared with parental CRC cells and reverse methotrexate-resistance in methotrexate-resistant CRC. GEO database and R software were utilized to analyze the gene expression profiles GSE11440 and GSE16066. Venn diagram was used to identify intersection differentially expressed genes (DEGs) between GSE11440 and GSE16066. Protein-protein interaction (PPI) was utilized to screen out central node genes. Hub genes were determined by volcano graphs, heatmaps and box plots. The functional enrichment analysis was exhibited with DAVID. The GEPIA was used to obtain survival curves to analyze association between patient prognosis and hub genes. Western blotting was used to detect the expressions of hub genes. CCK-8 assay was used to show MTX-resistant CRC cell viability following CD44 inhibitor (THIQ) and AGT inhibitor (O⁶-BG) treatments. In our results, there were 180 intersection DEGs between GSE11440 and GSE16066. CD44 and AGT were screened out as hub genes by PPI, heatmaps, volcano and box plots. In the 2 MTX-resistant CRC cells, the expressions of CD44 and AGT were up-regulated compared with parental CRC cells. The results of western blotting showed that CD44 and AGT were up-regulated in MTX-resistant HT29 and Caco2 cells compared with parental CRC cells. CCK-8 assay results showed that the combination of MTX with O⁶-BG or THIQ could significantly reduce the activity of MTX-resistant CRC cells. This research screened out CD44 and AGT in MTX-resistant CRC cells by bioinformatics and suggested that the combination of MTX with O⁶-BG or THIQ could enhance the sensitivity of MTX-resistant CRC cells to MTX. This research provides a new strategy for overcoming MTX-resistance in CRC.

Spatially resolved quantification of drug metabolism and efficacy in 3D paper-based tumor mimics

Paper-based cultures are an emerging platform for preparing three-dimensional (3D) tissue- and tumor-like structures. The ability to stack individual sheets of cell-containing paper affords a modular means of assembling structures with defined cellular compositions and microenvironments. These layered stacks are easily separated at the end of an experiment, providing spatially resolved populations of live cells for further analysis. Here we describe a workflow in which cell viability, drug penetration, and drug metabolism are quantified in a spatially resolved manner. Specifically, we mapped the distribution of the drug irinotecan and its bioactive metabolite SN38 in a colorectal cancer cell-containing stacked structure with liquid chromatography-mass spectrometry (LC-MS). This paper provides the first example of a 3D culture platform that quantifies viability and drug metabolism in a spatially resolved manner. Our data show that cells at the bottom of the stack are more drug-resistant than layers in contact with the culture medium, similar to cells in the nutrient-poor center of a proliferating tumor being more drug-resistant than the rapidly dividing cells at its periphery. The powerful combination of quantitative viability and drug metabolism measurements will enable future studies to determine the exact mechanism(s) of drug resistance in different regions of a tumor.

Curcumin induces apoptosis through caspase dependent pathway in human colon carcinoma cells

BACKGROUND

We investigated the apoptotic effects of curcumin in the colon carcinoma cell line SW480.

METHODS AND RESULTS

Cells were treated with 40-200 μM curcumin for 24, 48, and 72 h, and the IC₅₀ values were determined for each time interval. BrdU, caspase-3, and TUNEL staining results and the gene expression of FADD, CASP8, and CASP3 were evaluated. Curcumin treatments significantly inhibited cell proliferation and significantly induced apoptosis for 24, 48, and 72 h. The proportion of BrdU-stained cells in the control groups were 58%, 57% and 61% and 28%, 27%, and 30% in the curcumin treatment groups at 24, 48, and 72 h, respectively. The proportion of apoptotic cells was 28%, 29%, and 28% in the control groups and 59%, 61%, and 60% in the curcumin treatment groups at 24, 48, and 72 h, respectively. As expected, caspase-3 staining also revealed a higher number of apoptotic cells in curcumin treatment groups at 24, 48, and 72 h compared to controls. The proportion of Caspase-3-stained cells in the control groups were 23%, 25%, and 24% and 59%, 60%, and 62% in the curcumin treatment groups at 24, 48, and 72 h, respectively. To prove caspase-3 staining results, FADD, CASP8, and CASP3 gene expressions were evaluated by real-time qPCR. Unlike the immunohistochemical results, no statistically significant upregulation was found at 24 and 48 h, while relative gene expressions of FADD, CASP8, and CASP3 was significantly upregulated at 72 h. The expression level increase was 0.88-, 1.19-, and 2.11-fold for FADD, 1.25-, 1.29-, and 1.59-fold for CASP8, and 1.33-, 1.46-, and 3.00-fold for CASP3 at 24, 48, and 72 h, respectively.

CONCLUSIONS

These results suggest that curcumin may be a potential protective or treatment agent against colon cancer; however, further studies on curcumin-rich diets and curcumin bioavailability are required.

Nrf3 Promotes 5-FU Resistance in Colorectal Cancer Cells via the NF-κB/BCL-2 Signaling Pathway In Vitro and In Vivo

Increasing evidence indicates that nuclear factor, erythroid 2-like 3 (Nrf3) is connected with tumorigenesis. However, the relationship between Nrf3 and tumor drug resistance remains elusive. In this study, we investigated the effect and mechanism of action by which Nrf3 regulated the sensitivity of colon cancer cells to 5-fluorouracil (5-FU). We found Nrf3 was significantly increased in colon cancer tissues. Furthermore, we observed that Nrf3 knockdown and overexpression can significantly affect the sensitivity of colon cancer cells to 5-FU in vitro and in vivo. Moreover, Nrf3 promoted the expression of RELA, P-RELA, and BCL-2. Inhibition of NF-κB partly reversed the effects of Nrf3 overexpression, resulting in the resistance of colon cancer cells to 5-FU. Overall, the study revealed that Nrf3 was connected to the sensitivity of colon cancer cells to 5-FU, and its possible mechanism was related to the NF-κB signaling pathway, which provided a new target for overcoming the resistance of colon cancer cells to 5-FU.

Regulation of signal transduction pathways in colorectal cancer: implications for therapeutic resistance

Resistance to anti-cancer treatments is a critical and widespread health issue that has brought serious impacts on lives, the economy and public policies. Mounting research has suggested that a selected spectrum of patients with advanced colorectal cancer (CRC) tend to respond poorly to both chemotherapeutic and targeted therapeutic regimens. Drug resistance in tumours can occur in an intrinsic or acquired manner, rendering cancer cells insensitive to the treatment of anti-cancer therapies. Multiple factors have been associated with drug resistance. The most well-established factors are the emergence of cancer stem cell-like properties and overexpression of ABC transporters that mediate drug efflux. Besides, there is emerging evidence that signalling pathways that modulate cell survival and drug metabolism play major roles in the maintenance of multidrug resistance in CRC. This article reviews drug resistance in CRC as a result of alterations in the MAPK, PI3K/PKB, Wnt/β-catenin and Notch pathways.

D-MT prompts the anti-tumor effect of oxaliplatin by inhibiting IDO expression in a mouse model of colon cancer

Colon cancer is one of the most common malignant tumors in the digestive system. Although oxaliplatin, a chemotherapy drug, has been clinically used to treat colon cancer, its therapeutic effect is unsatisfactory. It has been proved that indoleamine dioxygenase 2,3 (IDO) is a tumor immunosuppressive factor for the immune response. Herein, an IDO inhibitor, D-MT (indoximod, 1-Methyl-D-tryptophan), was combined with oxaliplatin to treat colon cancer in mice. T cell infiltration in tumor tissues, the ratios of immune cells in the spleens, and the tumor growth and survival of the mice were detected and recorded. The results showed that the combination of oxaliplatin and D-MT significantly inhibited tumor growth and prolonged the survival of tumor-bearing mice. More importantly, the combination treatment increased the ratios of CD4⁺ T, CD8⁺ T and NK cells from the spleen in tumor-bearing mice, and prompted T cell infiltration in tumor tissues. This study provided a new therapeutic strategy for colon cancer treatment in the clinic, especially for patients with oxaliplatin resistance.

Targeting Drug Chemo-Resistance in Cancer Using Natural Products

Cancer is one of the leading causes of death globally. The development of drug resistance is the main contributor to cancer-related mortality. Cancer cells exploit multiple mechanisms to reduce the therapeutic effects of anticancer drugs, thereby causing chemotherapy failure. Natural products are accessible, inexpensive, and less toxic sources of chemotherapeutic agents. Additionally, they have multiple mechanisms of action to inhibit various targets involved in the development of drug resistance. In this review, we have summarized the basic research and clinical applications of natural products as possible inhibitors for drug resistance in cancer. The molecular targets and the mechanisms of action of each natural product are also explained. Diverse drug resistance biomarkers were sensitive to natural products. P-glycoprotein and breast cancer resistance protein can be targeted by a large number of natural products. On the other hand, protein kinase C and topoisomerases were less sensitive to most of the studied natural products. The studies discussed in this review will provide a solid ground for scientists to explore the possible use of natural products in combination anticancer therapies to overcome drug resistance by targeting multiple drug resistance mechanisms.

Blockade of Glycosphingolipid Synthesis Inhibits Cell Cycle and Spheroid Growth of Colon Cancer Cells In Vitro and Experimental Colon Cancer Incidence In Vivo

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers in humans. At early stages CRC is treated by surgery and at advanced stages combined with chemotherapy. We examined here the potential effect of glucosylceramide synthase (GCS)-inhibition on CRC biology. GCS is the rate-limiting enzyme in the glycosphingolipid (GSL)-biosynthesis pathway and overexpressed in many human tumors. We suppressed GSL-biosynthesis using the GCS inhibitor Genz-123346 (Genz), NB-DNJ (Miglustat) or by genetic targeting of the GCS-encoding gene UDP-glucose-ceramide-glucosyltransferase- (UGCG). GCS-inhibition or GSL-depletion led to a marked arrest of the cell cycle in Lovo cells. UGCG silencing strongly also inhibited tumor spheroid growth in Lovo cells and moderately in HCT116 cells. MS/MS analysis demonstrated markedly elevated levels of sphingomyelin (SM) and phosphatidylcholine (PC) that occurred in a Genz-concentration dependent manner. Ultrastructural analysis of Genz-treated cells indicated multi-lamellar lipid storage in vesicular compartments. In mice, Genz lowered the incidence of experimentally induced colorectal tumors and in particular the growth of colorectal adenomas. These results highlight the potential for GCS-based inhibition in the treatment of CRC.

The Cytotoxicity of Doxorubicin Can Be Accelerated by a Combination of Hyperthermia and 5-Aminolevulinic Acid

Chemotherapy is cytotoxic to various cancer cells and as well as normal cells. Thus, treatments that demonstrate selective cytotoxicity for cancer cells are desired. The combination of chemotherapy and other cancer therapies can show synergic cytotoxicity, which may be a clue to the nature of the involved cancer cellar-specific damage. We previously reported a phenomenon whereby mitochondrial reactive oxygen species (mitROS) regulate the expression transporters involved in anticancer drug transport and mitROS production is increased by hyperthermia. Moreover, the uptake of 5-aminolevulinic acid (ALA) was enhanced by the increase in mitROS production. In this study, we investigated whether the combination of hyperthermia and ALA can enhance the cytotoxicity of doxorubicin. MitROS production and ALA-derived porphyrin accumulation by hyperthermia (HT) were increased in a murine breast cancer cell line. The expression of solute carrier 15A1 (SLC15A1) upregulated and an ATP-binding cassette subfamily G member 2 (ABCG2) downregulated by HT. Since SLC15A1 is an accumulating transporter for ALA, while ABCG2 is a porphyrin efflux transporter, porphyrin accumulation was enhanced. ABCG2 is also a doxorubicin efflux transporter. Thus, ALA treatment accelerates the intracellular concentration of porphyrin, which acts as a competitive inhibitor of doxorubicin. Indeed, the amount of intracellular doxorubicin was increased by a combination of HT and ALA. The cytotoxicity of doxorubicin was also enhanced. This enhancement was observed in the human breast cancer cell line while it was not seen in normal cells. The combination of HT and ALA treatment can enhance the cancer-specific cytotoxicity of doxorubicin.

Natural substances derived from herbs or plants are promising sources of anticancer agents against colorectal cancer via triggering apoptosis

OBJECTIVES

Nowadays, one of the most common gastrointestinal cancers is colorectal cancer (CRC). Chemotherapy is still one of the main methods to treat cancer. However, the currently available synthetic chemotherapy drugs often cause serious adverse reactions. Apoptosis is generally considered as an ideal way for induction the death of tumour cells without the body's inflammatory response, and it is reported that lots of natural agents could trigger various cancer cells to apoptosis. The overarching aim of this project was to elucidate the specific mechanisms by which natural substances induce apoptosis in CRC cells and to be used as an alternative therapeutic option in the future.

KEY FINDINGS

The mechanisms for the pro-apoptotic effects of natural substances derived from herbs or plants include death receptor pathway, mitochondrial pathway, endoplasmic reticulum stress pathway, related signal transduction pathways (PI3K/Akt, MAPK, p53 signalling), and so on.

SUMMARY

This paper updated this information regarding the anti-tumour effects of natural agents via induction of apoptosis against CRC, which would be beneficial for future new drug research regarding natural products from herbs or plants.

In Vitro Tumor Cell Growth Inhibition Induced by Lophocereus marginatus (DC.) S. Arias and Terrazas Endophytic Fungi Extracts

Endophytic fungi have become potential sources of antitumor agents, particularly against antineoplastic-resistant cancer cells, with marginal or nil adverse effects for the oncological patient. Endophytic fungi were isolated from stems of the Lophocereus marginatus cactus, commonly found in Mexico. Methanol extracts were then obtained from fungus liquid cultures and their effects on tumor cell growth against murine lymphoma (L5178Y-R), human colorectal adenocarcinoma (HT-29), and human breast cancer (MCF-7) cells were evaluated at concentrations ranging from 31 µg/mL to 250 µg/mL via the colorimetric 3- [4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazoliumbromide reduction assay, using monkey kidney epithelial (MA-104) and human peripheral mononuclear (PBMC) cells as controls. Furthermore, we obtained the IC50 and the selectivity index (SI) was calculated from the IC50 ratio of normal and tumor cells. In addition, molecular identification of fungi showing cytotoxic activity was determined, using internal transcribed spacer molecular markers. PME-H001, PME-H002, PME-H005, PME-H007, and PME-H008 filamentous fungus strain extracts showed significant (p < 0.05) tumor cell growth inhibition. In particular, they significantly (p < 0.05) inhibited L5178Y-R cell growth, whereas the least susceptible cell line was HT-29. The endophytic strain PME-H008 of Cladosporium sp. caused the highest growth inhibition percentage against L5178Y-R and HT-29 cells with 96.6% (p < 0.01) and 42.5% (p < 0.05) respectively, and the highest SIs against L5178Y-R cells with 2.4 and 2.9 for MA-104 and PBMCs, respectively, whereas the PME-H005 extract showed SIs of 2.77 and 1.5 against MCF-7 and L5178Y-R cells, respectively, as compared with PBMCs. In addition, the endophytic strain PME-H007 of Metarhizium anisopliae caused the highest percentage of growth inhibition (p < 0.01) against MCF-7 cells with 55.8% at 250 µg/mL. We demonstrated in vitro antitumor effects of L. marginatus endophytic fungi. Further research will involve the isolation and in vivo testing of bioactive compounds.

Casein Kinase-1-Alpha Inhibitor (D4476) Sensitizes Microsatellite Instable Colorectal Cancer Cells to 5-Fluorouracil via Authophagy Flux Inhibition

Adjuvant chemotherapy with 5-fluorouracil (5-FU) does not improve survival of patients suffering from a form of colorectal cancer (CRC) characterized by high level of microsatellite instability (MSI-H). Given the importance of autophagy and multi-drug-resistant (MDR) proteins in chemotherapy resistance, as well as the role of casein kinase 1-alpha (CK1α) in the regulation of autophagy, we tested the combined effect of 5-FU and CK1α inhibitor (D4476) on HCT116 cells as a model of MSI-H colorectal cancer. To achieve this goal, the gene expression of Beclin1 and MDR genes, ABCG2 and ABCC3 were analyzed using quantitative real-time polymerase chain reaction. We used immunoblotting to measure autophagy flux (LC3, p62) and flow cytometry to detect apoptosis. Our findings showed that combination treatment with 5-FU and D4476 inhibited autophagy flux. Moreover, 5-FU and D4476 combination therapy induced G2, S and G1 phase arrests and it depleted mRNA of both cell proliferation-related genes and MDR-related genes (ABCG2, cyclin D1 and c-myc). Hence, our data indicates that targeting of CK1α may increase the sensitivity of HCT116 cells to 5-FU. To our knowledge, this is the first description of sensitization of CRC cells to 5-FU chemotherapy by CK1α inhibitor.

STIL Endows Oncogenic and Stem-Like Attributes to Colorectal Cancer Plausibly by Shh and Wnt Signaling

The discovery of a potent gene regulating tumorigenesis and drug resistance is of high clinical importance. STIL is an oncogene; however, its molecular associations and role in colorectal oncogenesis are unknown. In this study, we have explored the role of STIL gene in tumorigenesis and studied its molecular targets in colorectal cancer (CRC). STIL silencing reduced proliferation and tumor growth in CRC. Further, STIL was found to regulate stemness markers CD133 and CD44 and drug resistant markers thymidylate synthase, ABCB1, and ABCG2 both in in-vitro and in-vivo CRC models. In addition, high expression of STIL mRNA was found to be associated with reduced disease-free survival in CRC cases. Interestingly, we observed that STIL-mediated regulation of stemness and drug resistant genes is not exclusively governed by Sonic hedgehog (Shh) signaling. Remarkably, we found STIL regulate β-catenin levels through p-AKT, independent of Shh pathway. This partially answers Shh independent regulatory mechanism of cancer stem cell (CSC) markers by STIL. Our study suggests an instrumental role of STIL in molecular manifestation of CRC and progression.

New Advances in the Research of Resistance to Neoadjuvant Chemotherapy in Breast Cancer

Breast cancer has an extremely high incidence in women, and its morbidity and mortality rank first among female tumors. With the increasing development of medicine today, the clinical application of neoadjuvant chemotherapy has brought new hope to the treatment of breast cancer. Although the efficacy of neoadjuvant chemotherapy has been confirmed, drug resistance is one of the main reasons for its treatment failure, contributing to the difficulty in the treatment of breast cancer. This article focuses on multiple mechanisms of action and expounds a series of recent research advances that mediate drug resistance in breast cancer cells. Drug metabolizing enzymes can mediate a catalytic reaction to inactivate chemotherapeutic drugs and develop drug resistance. The drug efflux system can reduce the drug concentration in breast cancer cells. The combination of glutathione detoxification system and platinum drugs can cause breast cancer cells to be insensitive to drugs. Changes in drug targets have led to poorer efficacy of HER2 receptor inhibitors. Moreover, autophagy, epithelial–mesenchymal transition, and tumor microenvironment can all contribute to the development of resistance in breast cancer cells. Based on the relevant research on the existing drug resistance mechanism, the current treatment plan for reversing the resistance of breast cancer to neoadjuvant chemotherapy is explored, and the potential drug targets are analyzed, aiming to provide a new idea and strategy to reverse the resistance of neoadjuvant chemotherapy drugs in breast cancer.

Osthole induces apoptosis of the HT-29 cells via endoplasmic reticulum stress and autophagy

Endoplasmic reticulum stress (ERS) and autophagy are important pathways, which induce apoptosis of tumor cells. Osthole has been demonstrated to exert anticancer effects via the induction of apoptosis in several human colon cancer lines, but the mechanism underlying its involvement in the induction of ERS and autophagy in the human HT-29 colorectal cancer cell line remains unknown. The present study aimed to identify the possible signaling pathways involved in osthole-induced apoptosis of HT29 cells. Methodologically, colony formation and Cell Counting Kit-8 assays were used to assess cell proliferation and viability, respectively, while flow cytometry was performed to investigate apoptosis. Signaling pathways, including apoptosis, autophagy and ERS, were also investigated in the HT-29 cell line using western blot analysis. The results demonstrated that osthole inhibited cellular proliferation and viability in a dose-dependent manner. In addition, osthole induced the expression level of proteins associated with mitochondria-mediated cell apoptosis, autophagy and ERS. The association between autophagy and ERS in osthole-induced apoptosis in the HT-29 cell line was further clarified. Inhibiting cell autophagy with the inhibitor, 3-methyladenine, suppressed osthole-induced cell apoptosis and enhanced osthole-induced ERS. By contrast, alleviating ERS with the inhibitor, 4-phenylbutyric acid attenuated osthole-induced cell apoptosis and autophagy. In conclusion, osthole could significantly suppress the proliferation and viability of the HT-29 colorectal cancer cell line and induce cell apoptosis via autophagy and ERS. Furthermore, ERS may play a more important role in osthole-induced cell apoptosis.

Thermodynamic Genome-Scale Metabolic Modeling of Metallodrug Resistance in Colorectal Cancer

Simple Summary

Cancer, but also its treatment, can lead to a reprogramming of cellular metabolism. These changes are observable in metabolite abundances, which can be unbiasedly measured via mass spectrometry metabolomics. However, even when the metabolome changes strongly, a (mechanistic) interpretation is difficult as metabolite levels do not necessarily directly correspond to pathway activities. Here we measure the changes of the cellular metabolome in colorectal cancer cell lines sensitive and resistant to the ruthenium-based drug BOLD-100/KP1339 and the platinum-based drug oxaliplatin. We map these changes onto a cancer-specific genome-scale metabolic model, which allows us not only to compute intracellular flux distributions, but also to disentangle drug-specific effects from growth differences from differences in metabolic adaptations due to resistance. Specifically, we find that resistance to BOLD-100/KP1339 induces more extensive reprogramming than oxaliplatin, especially with respect to fatty acid and amino acid metabolism.

Abstract

Background: Mass spectrometry-based metabolomics approaches provide an immense opportunity to enhance our understanding of the mechanisms that underpin the cellular reprogramming of cancers. Accurate comparative metabolic profiling of heterogeneous conditions, however, is still a challenge. Methods: Measuring both intracellular and extracellular metabolite concentrations, we constrain four instances of a thermodynamic genome-scale metabolic model of the HCT116 colorectal carcinoma cell line to compare the metabolic flux profiles of cells that are either sensitive or resistant to ruthenium- or platinum-based treatments with BOLD-100/KP1339 and oxaliplatin, respectively. Results: Normalizing according to growth rate and normalizing resistant cells according to their respective sensitive controls, we are able to dissect metabolic responses specific to the drug and to the resistance states. We find the normalization steps to be crucial in the interpretation of the metabolomics data and show that the metabolic reprogramming in resistant cells is limited to a select number of pathways. Conclusions: Here, we elucidate the key importance of normalization steps in the interpretation of metabolomics data, allowing us to uncover drug-specific metabolic reprogramming during acquired metal-drug resistance.

Dihydrotanshinone exerts antitumor effects and improves the effects of cisplatin in anaplastic thyroid cancer cells

Anaplastic thyroid cancer (ATC) is the most aggressive type of thyroid cancer and is responsible for 20‑50% of thyroid cancer‑associated deaths. The absence of response to conventional treatments makes the search for novel therapeutics a clinical challenge. In the present study, the effects of 15,16‑dihydrotanshinone I (DHT), a tanshinone extracted from Salvia miltiorrhiza Bunge (Danshen), which has previously been shown to possess anticancer activity, were examined in two human ATC cell lines. DHT significantly reduced cell viability, which was coupled with an increase in apoptosis. DHT administration also reduced the colony‑forming ability and proliferation of these cells in soft agar and downregulated the expression of epithelial‑to‑mesenchymal transition‑related genes. In addition, DHT significantly reduced MAD2 expression, a target of HuR with a relevant role in ATC. Finally, cotreatment with cisplatin and DHT has a greater effect on cell viability than each compound alone. In conclusion, to the best of our knowledge, the present study is the first to demonstrate that DHT exerts antitumor effects on ATC cells by reducing MAD2 expression levels. Moreover, a synergistic effect of DHT with cisplatin was shown. Further in vivo studies are required to assess this phytochemical compound as a potential adjuvant for the treatment of ATC.

Hsa_circ_0136666 activates Treg-mediated immune escape of colorectal cancer via miR-497/PD-L1 pathway

PURPOSE

In the rankings of cancer mortality and incidence worldwide, colorectal cancer ranks fourth and the third, respectively. Circular RNA hsa_circ_0136666 (hsa_circ_0136666) is reported to participate in the growth of colorectal cancer. However, the mechanism by which hsa_circ_0136666 regulates the tumorigenesis of colorectal cancer needs to be further explored. In this study, we report here the role of hsa_circ_0136666 in the aberrant activation of Treg cells and immune evasion of tumor cells, providing a new strategy for the treatment of colorectal cancer.

METHODS

Western blotting assay and qRT-PCR assay were used to determine protein and mRNA expression levels. Dual-luciferase reporter assay was used to evaluate the targeted regulatory relationship. RNA immunoprecipitation was used to detect RNA binding. Colony formation assay was utilized to measure the cell proliferation. Flow cytometry was used to assess cell apoptosis. Xenograft model was setup to evaluate tumor growth.

RESULTS

The results showed that hsa_circ_0136666 and PD-L1 was increased in colorectal cancer cells while miR-497 was decreased in colorectal cancer cells when compared with normal colon epithelial cell line. Hsa_circ_0136666 was demonstrated to directly target miR-497, which also regulated PD-L1 by binding to its 3'UTR. Further mechanistic studies identified that hsa_circ_0136666 controlled cell proliferation and apoptosis via targeting miR-497 and regulating PD-L1 expression. Of note, hsa_circ_0136666 stimulated Treg cells mediated by miR-497/PD-L1 axis and its downstream signal pathway in Treg cells. Finally, hsa_circ_0136666 was found to accelerate the tumor growth in vivo.

CONCLUSIONS

Our findings demonstrated that hsa_circ_0136666 promoted the expression of PD-L1 by inhibiting miR-497 level in colorectal cancer, thus inducing the activation of Treg cells and leading to the immune escape of tumor, providing a novel mechanistic insight into the pathogenesis of colorectal cancer.

mRNA expression level of CDH2, LEP, POSTN, TIMP1 and VEGFC modulates 5-fluorouracil resistance in colon cancer cells

Drug resistance severely affects the clinical efficacy of therapeutic agents in patients with colon cancer. The aim of the present study was to identify genes involved in drug resistance in colon cancer using bioinformatics analysis and to identify the underlying mechanisms in vitro. Genes associated with cancer recurrence and chemotherapy resistance were identified using data mining. Immunohistochemistry was performed to analyze the protein expression level of genes of interest in human colon cancer tissues. Reverse transcription-quantitative PCR analysis was performed to analyze the gene expression level in patient samples and in colon cancer cell lines (HCT116 and LoVo). Cell viability was evaluated using the Cell Counting Kit-8 assay in the colon cancer cell lines. Apoptosis was measured using PI staining. The results from the present study revealed 602 genes using both ‘cancer recurrence’ and ‘chemoresistance’ terms on the GenCLiP3 website. Gene functional annotation was performed using the Database for Annotation, Visualization and Integrated Discovery then, the protein-protein interaction networks of the 602 genes were analyzed using STRING analysis. Further, in the GEPIA database, 14 genes (ATM, CDH2, CDKN2A, EPO, LEP, TGFB1, TIMP1, PGR, VEGFC, POSTN, BCL6, CYP19A1, NOTCH3 and XPA) were found to be upregulated in colon cancer tissue and were associated with poor prognosis in patients with colon cancer. Further analysis of 33 paired human colon cancer tissues revealed that 8 genes (ATM, CDH2, CDKN2A, LEP, PGR, TIMP1, POSTN and VEGFC) were significantly upregulated, which was consistent with the results obtained from the earlier analysis and 5 genes (CDH2, LEP, POSTN, TIMP1 and VEGFC) were associated with patient prognosis. Silencing of these 5 genes using small interfering RNAs significantly enhanced the sensitivity of colon cancer cells to the chemotherapeutic agent, 5-fluorouracil (5-FU). Taken together, the results suggested that CDH2, LEP, POSTN, TIMP1 and VEGFC might play a role in chemotherapeutic resistance in colon cancer and represent potential targets for overcoming 5-FU resistance in colon cancer.

Role of ferroptosis-related genes in prognostic prediction and tumor immune microenvironment in colorectal carcinoma

Background and Aim

Colorectal cancer (CRC) ranks the second most common cause of cancer-related mortality worldwide. Ferroptosis, a recently discovered form of programmed cell death different from other, raises promising novel opportunities for therapeutic intervention of CRC. This study intended to systematically assess the prognosis value and multiple roles of the ferroptosis-related genes in the tumor immune microenvironment of CRC.

Materials and Methods

Of 1,192 CRC patients with complete information from the public datasets (TCGA CRC, GEO GSE39582 and GSE17538 cohorts) were selected for analysis. Firstly, K-means consensus clustering was performed to identify ferroptosis-associated subtypes in CRC patients. Subsequently, we constructed a risk signature based on ferroptosis-related genes in TCGA cohort and acquired its validation in two GEO cohorts. Additionally, we established a nomogram integrating the risk signature and clinical factors to improve risk assessment of CRC patients.

Results

Five molecular subtypes were identified by consensus clustering for ferroptosis-related genes. There were significant differences in the overall survival, immune cells infiltration status and PD1/PD-L1 mRNA among the five clusters. Then, a risk signature based on the ten-gene was constructed which could distinguish effectively high-risk group among CRC patients in both training and validation sets. The high-risk patients were more likely to have an inhibitory immune microenvironment and lower stemness features. A prognostic nomogram integrated risk signature and clinicopathological features could be used as a more accurate prognostic prediction visualization tool than TNM stage alone.

Conclusion

This ferroptosis risk signature may accurately differentiate between different risk populations and predict the prognosis of CRC. Besides, this study elucidated the crucial role of ferroptosis in tumor immune microenvironment.

Rauwolfia vomitoria Extract Represses Colorectal Cancer Cell Autophagy and Promotes Apoptosis

BACKGROUND

Colorectal cancer (CRC) is one of the most frequent digestive tract tumors in the world with an increasing incidence. Currently, surgical resection and chemotherapy are the main therapeutic options; however, their effects are limited by various adverse reactions. Rauwolfia vomitoria extract (Rau) has been shown to repress the progression of multiple human cancers; however, whether Rau plays a role in CRC remains undetermined.

METHODS

Influences of Rau treatment on HCT-116 and LoVo cells were estimated via MTT and colony formation experiments. Flow cytometry analysis was adopted to evaluate the apoptosis rate of HCT-116 and LoVo cells. Apoptosis-related proteins (Bcl-2, Bax, and caspase-3) and autophagy-related proteins (LC3 and P62) were assessed by Western blotting. Effects of Rau on autophagy of HCT-116 and LoVo cell were evaluated through GFP-LC3 analysis. In vivo xenograft tumor assay was conducted to further examine the role of Rau in CRC tumor growth.

RESULTS

Rau remarkably repressed HCT-116 and LoVo cell viability and promoted HCT-116 and LoVo cell apoptosis in vitro in a dose-dependent manner. Rau increased the expression of caspase-3 and Bax and decreased the expression of Bcl-2 in HCT-116 and LoVo cells. Moreover, Rau was demonstrated to decrease the LC3||/LC3| ratio and increase the level of P62 in HCT-116 and LoVo cells. In addition, we found that Rau repressed xenograft tumor growth and also repressed autophagy in vivo.

CONCLUSION

Our findings revealed that Rau repressed CRC cell viability and autophagy in vitro and in vivo, suggesting that Rau might be a potent therapeutic agent of CRC.

C. tropicalis promotes chemotherapy resistance in colon cancer through increasing lactate production to regulate the mismatch repair system

Due to chemotherapeutic drug resistance, tumor recurrence is common in patients with colorectal cancer (CRC) and chemo-resistant patients are often accompanied by defects in the mismatch repair system (MMR). Our previous study has shown that Candida tropicalis (C. tropicalis) is closely related to the occurrence and development of colorectal cancer, but whether this conditional pathogenic fungus is involved in chemotherapy needs further investigation. Here we found that C. tropicalis promoted chemotherapy resistance of colon cancer to oxaliplatin. Compared with oxaliplatin-treated group, the expression of functional MMR proteins in tumors were decreased in C.tropicalis/oxaliplatin -treated group, while the glycolysis level of tumors was up-regulated and the production of lactate was significantly increased in C.tropicalis/oxaliplatin -treated group. Inhibiting lactate production significantly alleviated the chemoresistance and rescued the decreased expression of MMR caused by C. tropicalis. Furthermore, we found that lactate down-regulated the expression of MLH1 through the GPR81-cAMP-PKA-CREB axis. This study clarified that C. tropicalis promoted chemoresistance of colon cancer via producing lactate and inhibiting the expression of MLH1, which may provide novel ideas for improving CRC chemotherapy effect.

The Impact of Extracellular Ca2+ and Nanosecond Electric Pulses on Sensitive and Drug-Resistant Human Breast and Colon Cancer Cells

Simple Summary

The drug resistance phenomenon in cancer constantly induces problems in therapeutic protocols. Pulsed electric fields (PEFs) seem to be a promising method in drug molecule delivery. Here we have proved that electroporation supported by calcium ions can alternate the activity of drug resistance proteins. Our results indicated that MDR1 expression is not significantly modified by nanosecond electroporation in multidrug-resistant cells. However, PEF significantly inhibited MDR1 activity and cell viability when combined with calcium ions.

Abstract

(1) Background: Calcium electroporation (CaEP) is based on the application of electrical pulses to permeabilize cells (electroporation) and allow cytotoxic doses of calcium to enter the cell. (2) Methods: In this work, we have used doxorubicin-resistant (DX) and non-resistant models of human breast cancer (MCF-7/DX, MCF-7/WT) and colon cancer cells (LoVo, LoVo/DX), and investigated the susceptibility of the cells to extracellular Ca²⁺ and electric fields in the 20 ns–900 ns pulse duration range. (3) Results: We have observed that colon cancer cells were less susceptible to PEF than breast cancer cells. An extracellular Ca²⁺ (2 mM) with PEF was more disruptive for DX-resistant cells. The expression of glycoprotein P (MDR1, P-gp) as a drug resistance marker was detected by the immunofluorescent (CLSM) method and rhodamine-123 efflux as an MDR1 activity. MDR1 expression was not significantly modified by nanosecond electroporation in multidrug-resistant cells, but a combination with calcium ions significantly inhibited MDR1 activity and cell viability. (4) Conclusions: We believe that PEF with calcium ions can reduce drug resistance by inhibiting drug efflux activity. This phenomenon of MDR mechanism disruption seems promising in anticancer protocols.

Inhibitory effects of piperine on proliferation, migration, and invasion of human colon cancer SW480 cells

BACKGROUND

Many recent reports have shown that piperine has anticancer activity, but the specific roles and biological mechanisms of piperine in colon cancer are not well studied.

AIM

To investigate the effects and potential mechanisms of piperine on the proliferation, migration, and invasion of human colon cancer SW480 cells.

METHODS

SW480 cells were treated with 0 (blank control), 5, 10, and 20 μg/mL piperine for 24 h, respectively. Cell viability was detected by cell counting kit-8 (CCK-8) assay. Proliferation was detected by 5-ethynyl-2'-deoxyuridine (EDU) staining. Cell migration and invasion were detected by Transwell assay. The protein expression levels of microtubule-associated light chain 3 (LC3), p53, B cell lymphoma/lewkmia-2 (Bcl-2), Bcl-2 associated X protein (Bax), and cleaved cysteine aspartate proteinase-3 (Cleaved caspase 3) were detected by Western blotting.

RESULTS

Piperine inhibited cell viability, proliferation, migration, and invasion in a concentration-dependent manner. Western blot analysis showed that piperine increased the expression of p53, Bax, and Cleaved caspase 3 but decreased the expression of Bcl-2 in SW480 cells compared with control cells.

CONCLUSION

Piperine can inhibit the proliferation, migration, and invasion of SW480 cells, and the mechanism may be related to the up-regulation of p53 signaling pathway and the induction of autophagic cell death.