Targeted molecular ablation of cancer stem cells for curing gastrointestinal cancers

Navigating the therapeutic landscape for breast cancer: targeting breast cancer stem cells

Breast cancer is a common and deadly malignancy that affects women globally, and breast cancer stem cells (BCSCs) play an important role in tumorigenesis, development, metastasis, and recurrence. Traditional therapies often fail to eliminate BCSCs, leading to treatment resistance and relapse. This review explores the therapeutic strategies which are designed to target BCSCs, including inhibition of key signaling pathway and targeting receptor. This paper also explores the approaches to targeting BCSCs including chemotherapy, phytomedicines, and nanotechnology. Nanotechnology has gained a lot of importance in cancer therapy because of its ability to deliver therapeutic agents with more precision and minimal side effects. Various chemotherapeutic drugs, siRNAs, or gene editing tools are delivered efficiently with the use of nanocarriers which target pathways, receptors, and proteins associated with BCSCs. Over the past few years, stimuli-responsive and receptor-targeted nanocarriers have been explored for better therapeutic effects. In recent times, strategies such as chimeric antigen receptor (CAR) T-cell therapy, ablation therapy, and cell-free therapies are explored for targeting these stem cells. This review provides a recent developmental overview of strategies to attack BCSCs from conventional chemotherapeutic agents to nanotechnological platforms such as polymeric, lipidic, and metal-based nanoparticles and advanced technologies like CAR T cell therapies.

THBS2 promotes gastric cancer progression and stemness via the Notch signaling pathway

Thrombospondin-2 (THBS2), a secreted extracellular matrix protein, plays a crucial role in various biological processes including angiogenesis, tissue remodeling, and inflammation. Our study focuses on its function in human gastric cancer (GC). Through bioinformatics and tumor tissue analysis, we compared THBS2 expression in GC tissues and adjacent tissues, and predicted regulatory upstream and downstream molecules. The direct regulatory effect of miR-29b-3p on THBS2 was evaluated through dual-luciferase reporter assays, showing that miR-29b-3p targets the 3'-UTR of THBS2 mRNA, reducing its expression in GC cells. The influence of THBS2 on tumorigenesis and stemness was examined on protein expression levels via Western blot. In vivo, THBS2's role was investigated through xenograft and metastasis assays in nude mice, demonstrating that downregulation of THBS2 impairs GC tumorigenesis and liver metastasis. Our study identified THBS2 as a highly expressed prognostic factor in GC patients. Functionally, THBS2 promotes GC progression through the Notch signaling pathway by regulating Notch3, NEY1, and HES1 proteins, and sustains cancer stem cell-like characteristics by Notch3, including the expression of CD44, Nanog, OCT4, and SOX2. In sum, our study reveals that THBS2 promotes GC progression and stemness, modulated negatively by miR-29b-3p. This suggests potential therapeutic targets within the THBS2/Notch signaling axis for combating gastric cancer.

Sphingomyelin synthase 2 promotes the stemness of breast cancer cells via modulating NF-κB signaling pathway

OBJECTIVES

Multi-drug resistance (MDR) to chemotherapy is the main obstacle influencing the anti-tumor effect in breast cancer, which might lead to the metastasis and recurrence of cancer. Until now, there are still no effective methods that can overcome MDR. In this study, we aimed to investigate the role of sphingomyelin synthase 2 (SMS2) in breast cancer resistance.

METHODS

Quantitative RT-PCR analysis was performed to assess changes in mRNA expression. Western blot analysis was performed to detect protein expression. Inhibitory concentration value of adriamycin (ADR) was evaluated using CCK 8 assay. The stemness ability of breast cancer cells was assessed by spheroid-formation assay. Immunofluorescence staining was conducted to show the cellular distribution of proteins. Breast tumor masses were harvested from the xenograft tumor mouse model.

RESULTS

SMS2 overexpression increased the IC50 values of breast cancer cells. SMS2 decreased the CD24 transcription level but increased the transcription levels of stemness-related genes including CD44, ALDH, OCT 4 and SOX2 in breast cancer cells. SMS2 overexpression promoted the nuclear translocation of phosphorylated NF-κB, while suppression of SMS2 could inhibit the NF-κB pathway.

CONCLUSIONS

SMS2 increased the stemness of breast cancer cells via NF-κB signaling pathway, leading to resistance to the chemotherapeutic drug ADR. Thus, SMS2 might play a critical role in the development of breast cancer resistance, which is a previously unrecognized mechanism in breast cancer MDR development.

Long-Term Usage of Proton Pump Inhibitors Associated with Prognosis in Patients with Colorectal Cancer

The dose-response effect of proton pump inhibitors on colorectal cancer prognosis is still under exploration. This population-based study in Taiwan was designed to examine the effect of proton pump inhibitors on overall death, colorectal cancer-specific death, and recurrence in colorectal cancer patients with different cumulative proton pump inhibitor dose levels. This cohort study was based on the Taiwan Cancer Registry and Taiwan National Health Insurance Research Database from 2005 to 2020. After frequency matching with a 1:1 ratio, a total of 20,889 users with proton pump inhibitors and 20,889 without proton pump inhibitors were analyzed. The cumulative defined daily dose level of proton pump inhibitor was stratified to explore the dose-response relationship. A proton pump inhibitor exposure cumulative defined daily dose > 60 after colorectal cancer diagnosis had higher risk of all-cause death than non-proton pump inhibitor users with adjusted hazard ratios of 1.10 (95% CIs: 1.04-1.18). For recurrence, a proton pump inhibitor exposure cumulative defined daily dose > 60 had reduced recurrence risk with an adjusted hazard ratio of 0.84 (95% CIs: 0.76-0.93). This study demonstrated that the long-term use of proton pump inhibitors in patients with colorectal cancer was associated with an increased risk of death that related to the proton pump inhibitor exposure cumulative defined daily dose > 60 and had different dose-response effect in various dose level.

Diallyl trisulfide inhibits gastric cancer stem cell properties through ΔNp63/sonic hedgehog pathway

Gastric cancer is one of the deadliest malignant tumors, and half of the patients develop recurrences or metastasis within 5 years after eradication therapy. Cancer stem cells (CSCs) are considered to be important in this progress. The sonic hedgehog (SHH) pathway plays an important role in the maintenance of gastric CSCs characteristics. The p63 proteins are vital transcription factors belonging to the p53 family, while their functions in regulating CSCs remain unclear. The preventive effects of dietary diallyl trisulfide (DATS) against human gastric cancer have been verified. However, whether DATS can target gastric CSCs are poorly understood. Here, we investigated the role of ΔNp63/SHH pathway in gastric CSCs and the inhibitory effect of DATS on gastric CSCs via ΔNp63/SHH pathway. We found that ΔNp63 was upregulated in serum-free medium cultured gastric tumorspheres compared with the parental cells. Overexpression of ΔNp63 elevated the self-renewal capacity and CSC markers' levels in gastric sphere-forming cells. Furthermore, we found that ΔNp63 directly bound to the promoter region of Gli1, the key transcriptional factor of SHH pathway, to enhance its expression and to activate SHH pathway. In addition, it was revealed that DATS effectively inhibited gastric CSC properties both in vitro and in vivo settings. Activation of SHH pathway attenuated the suppressive effects of DATS on the stemness of gastric cancer. Moreover, DATS suppression of gastric CSC properties was also diminished by ΔNp63 upregulation through SHH pathway activation. These findings illustrated the role of ΔNp63/SHH pathway in DATS inhibition of gastric cancer stemness. Taken together, the present study suggested for the first time that DATS inhibited gastric CSCs properties by ΔNp63/SHH pathway.

Enhanced binding of β-catenin and β-TrCP mediates LMPt's anti-CSCs activity in colorectal cancer

Cancer stem cells (CSCs), a subpopulation of tumor cells with the features of self-renewal, tumor initiation, and insensitivity to common physical and chemical agents, are the key to cancer relapses, metastasis, and resistance. Accessible CSCs inhibitory strategies are primarily based on small molecule drugs, yet toxicity limits their application. Here, we report a liposome loaded with low toxicity and high effectiveness of miriplatin, lipo-miriplatin (LMPt) with high miriplatin loading, and robust stability, exhibiting a superior inhibitory effect on CSCs and non-CSCs. LMPt predominantly inhibits the survival of oxaliplatin-resistant (OXA-resistant) cells composed of CSCs. Furthermore, LMPt directly blocks stemness features of self-renewal, tumor initiation, unlimited proliferation, metastasis, and insensitivity. In mechanistic exploration, RNA sequencing (RNA-seq) revealed that LMPt downregulates the levels of pro-stemness proteins and that the β-catenin-mediated stemness pathway is enriched. Further research shows that either in adherent cells or 3D-spheres, the β-catenin-OCT4/NANOG axis, the vital pathway to maintain stemness, is depressed by LMPt. The consecutive activation of the β-catenin pathway induced by mutant β-catenin (S33Y) and OCT4/NANOG overexpression restores LMPt's anti-CSCs effect, elucidating the key role of the β-catenin-OCT4/NANOG axis. Further studies revealed that the strengthened binding of β-catenin and β-TrCP initiates ubiquitination and degradation of β-catenin induced by LMPt. In addition,the Apc^Min/+transgenicmouse model, in which colon tumors are spontaneously formed, demonstrates LMPt's potent anti-non-CSCs activity in vivo.

Targeting Gastric Cancer Stem Cells to Enhance Treatment Response

Gastric cancer (GC) was the fourth deadliest cancer in the world in 2020, and about 770,000 people died from GC that year. The death of patients with GC is mainly caused by the metastasis, recurrence, and chemotherapy resistance of GC cells. The cancer stem cell theory defines cancer stem cells (CSCs) as a key factor in the metastasis, recurrence, and chemotherapy resistance of cancer. It considers targeting gastric cancer stem cells (GCSCs) to be an effective method for the treatment of GC. For GCSCs, genes or noncoding RNAs are important regulatory factors. Many experimental studies have found that some drugs can target the stemness of gastric cancer by regulating these genes or noncoding RNAs, which may bring new directions for the clinical treatment of gastric cancer. Therefore, this review mainly discusses related genes or noncoding RNAs in GCSCs and drugs that target its stemness, thereby providing some information for the treatment of GC.

Proton pump inhibitors and increased reporting odds of renal neoplasms: FAERS-based adverse event data mining and analysis

BACKGROUND

Long-term use of proton pump inhibitors (PPIs) is associated with some safety issues. In this study, data mining was carried out to discover the potential association between renal neoplasms and PPIs.

RESEARCH DESIGN AND METHODS

Neoplasms signals of PPIs were detected in the Food and Drug Administration Adverse Event Reporting System from 2014 to 2020 by examining the reporting odds ratio. Adjusted odds ratios were analyzed using logistic regression.

RESULTS

Signals were detected with respect to renal hemangioma, acquired or unspecified cystic kidney disease, and papillary and unspecified renal cell carcinoma, of which intervals between adverse effects onset and medication were 7.00 (3.33, 15.67) years, 5.00 (1.70, 10.25) years, and 7.00 (4.72, 12.25) years, respectively. The lansoprazole had the strongest signal. Adjusted odds ratios for PPIs associated with renal cell carcinoma in cases with or without acquired cystic kidney disease or chronic kidney disease were 1.67 [95% confidence interval (CI) 1.46-1.91] and 1.62 (95% CI 1.41-1.87).

CONCLUSIONS

Exposure to PPIs was related to the raised risk of renal neoplasms. Careful consideration should be given to the possibility of an increased risk when PPIs are administered.

Apatinib Suppresses Gastric Cancer Stem Cells Properties by Inhibiting the Sonic Hedgehog Pathway

The presence of gastric cancer stem cells (GCSCs) marks the onset of gastric carcinoma. The sonic hedgehog (SHH) pathway plays a vital role in the maintenance of GCSC characteristics. Apatinib has been approved in China for advanced gastric cancer (GC) treatment. However, whether apatinib can target GCSCs and affect the SHH pathway remains unclear. The present study aimed to investigate the underlying mechanism of apatinib’s antitumor effects on GC. The expression levels of GCSC markers and number of CD133⁺ cells were significantly elevated in the sphere-forming cells. Apatinib effectively suppressed GCSC traits by inhibiting tumorsphere formation and cell proliferation, suppressing GCSC markers expression and CD133⁺ cell number, and inducing apoptosis. Apatinib downregulated the activation of the SHH pathway; while upregulation of the SHH pathway attenuated the inhibitory effects of apatinib on GCSCs. Moreover, apatinib treatment significantly delayed tumor growth and inhibited GCSC characteristics in the xenograft model. Our data suggested that apatinib exhibited inhibitory effects on GCSCs by suppressing SHH pathway both in vitro and in vivo, thus providing new insights into the therapeutic application of apatinib in GCSC suppression and advanced gastric cancer treatment.

Dietary intake of fermented kimchi prevented colitis-associated cancer

Kimchi is composed of various chemopreventive phytochemicals and profuse probiotics, defining kimchi as probiotic foods. Concerns had increased on the modulation of intestinal microbiota on various kinds of systemic diseases. Under the hypothesis that dietary intake of kimchi can be ideal intervention for either ameliorating colitis or preventing colitic cancer, we performed the study to validate the efficolitic cancery of fermented kimchi on preventing colitic cancer. Using azoxymethane-initiated and dextran sulfate sodium-promoted colitic cancer models, we have administrated fermented or non-fermented kimchi to modulate colitic cancer preemptively. Detailed molecular mechanisms were explored. Preemptive administration of fermented kimchi significantly afforded colitic cancer prevention through attenuating inflammasomes (IL-18, IL-1β, caspase-1), enhancing antioxidative (NQO1, GST-π), imposing anti-proliferative (Bax, caspase-3, β-catenin), and affording cytoprotective actions (HSP70, 15-PGDH), while non-fermented kimchi did not prevent colitic cancer. Special recipe cancer preventive kimchi (cpkimchi) was more effective compared to standard recipe fermented kimchi (p<0.01), while non-fermented kimchi (kimuchi) worsened colitic cancer development, telling the importance of fermentation in cancer prevention. Repression of NF-kB p65, induction of tumor suppressive 15-PGDH, and inactivation of ERK1/2 by cpkimchi contributed to colitic cancer prevention. Dietary intake of cpkimchi ameliorated colitis and prevented colitic cancer via concerted anti-inflammatory, antioxidative, and anti-mutagenic actions.

Potential proton pump inhibitor-related adverse effects

Proton pump inhibitors (PPIs) are one of the most common medications taken by patients worldwide. PPIs are used to treat acid-related disorders, including gastroesophageal reflux disease, peptic ulcer disease, Helicobacter pylori infection, and nonsteroidal anti-inflammatory drug/stress ulceration. For some of these diseases, long-term treatment is necessary. With such prolonged use, concern and investigation into potential adverse effects has increased. In addition, data are available regarding potential anticancer effects of PPIs, especially regarding solid tumors. The aim of this review is to assess the literature on PPIs with regard to common concerns, such as drug-drug interactions, the intestinal microbiome, dementia and central nervous system disease, and osteoporosis, as well as to highlight potential negative and positive impacts of the drug in cancer.

Effect of Proton Pump Inhibitors on Colorectal Cancer

Proton pump inhibitors (PPIs) are administered commonly to aged people; however, their effect on colorectal cancer (CRC) has still not been fully elucidated. Here, we examined the effect of PPIs and consequent alkalization on CRC cells. PPI administration alkalized the fecal pH and increased serum gastrin concentration. PPI and pH8 treatment (alkalization) of CMT93 mouse colon cancer cells inhibited cell growth and invasion, increased oxidative stress and apoptosis, and decreased mitochondrial volume and protein levels of cyclin D1 and phosphorylated extracellular signal-regulated kinase (pERK) 1/2. In contrast, gastrin treatment enhanced growth and invasion, decreased oxidative stress and apoptosis, and increased mitochondrial volume and cyclin D1 and pERK1/2 levels. Concurrent treatment with a PPI, pH8, and gastrin increased aldehyde dehydrogenase activity and also enhanced liver metastasis in the BALB/c strain of mice. PPI administration was associated with Clostridiumperfringens enterotoxin (CPE) in CRC lesions. CPE treatment activated yes-associated protein (YAP) signals to enhance proliferation and stemness. The orthotopic colon cancer model of CMT93 cells with long-term PPI administration showed enhanced tumor growth and liver metastasis due to gastrin and YAP activation, as indicated by gastrin receptor knockdown and treatment with a YAP inhibitor. These findings suggest that PPI promotes CRC growth and metastasis by increasing gastrin concentration and YAP activation, resulting in gut flora alteration and fecal alkalization. These findings suggest that PPI use in colorectal cancer patients might create a risk of cancer promotion.

Targeting CD133 reverses drug-resistance via the AKT/NF-κB/MDR1 pathway in colorectal cancer

BACKGROUND

Recent studies have shown that multidrug resistance may be induced by the high stemness of cancer cells. Following prolonged chemotherapy, MDR protein 1 (MDR1) and CD133 increase in CRC, but the relationship between them is unclear.

METHODS

The relationship between MDR and CSC properties in CRC was determined via CCK-8 assay, apoptosis assay, DOX uptake and retention, immunohistochemistry, immunofluorescence and flow cytometry. The correlations between their expression levels were evaluated using Spearman's rank statistical test and the Mann-Whitney test. Furthermore, the effect of CD133 on the repression of the AKT/NF-κB/MDR1 signalling pathway was investigated in vitro and in vivo.

RESULTS

We found that CD133 increased with the emergence of drug-resistance phenotypes, and the high expression of MDR1/P-gp was consistently accompanied by positive expression of CD133 as demonstrated by the analysis of patient samples. Up- or downregulation of CD133 could regulate MDR via AKT/NF-κB/MDR1 signalling in CRC. A rescue experiment showed that the AKT/NF-κB signalling pathway is the main mechanism by which CD133 regulates MDR1/P-gp expression in CRC.

CONCLUSIONS

Taken together, our results suggest that targeting CD133 reverses drug resistance via the AKT/NF-κB/MDR1 pathway and that this pathway might serve as a potential therapeutic target to reverse MDR in CRC.

Drosha-independent miR-6778-5p strengthens gastric cancer stem cell stemness via regulation of cytosolic one-carbon folate metabolism

Drosha-dependent canonical microRNAs (miRNAs) play a crucial role in the biological functions and development of cancer. However, the effects of Drosha-independent non-canonical miRNAs remain poorly understood. In our previous work, we found a set of aberrant miRNAs, including some upregulated miRNAs, called Drosha-independent noncanonical miRNAs, in Drosha-knockdown gastric cancer (GC) cells. Surprisingly, Drosha-silenced GC cells still retained strong malignant properties (e.g., proliferation ability and cancer stem cell (CSC) characteristics), indicating that aberrantly upregulated non-canonical miRNAs may play an important role in the maintenance of the malignant properties in GC cells that express low Drosha levels. Here, we report that miR-6778-5p, a noncanonical miRNA, acts as a crucial regulator for maintenance of CSC stemness in Drosha-silenced GC cells. MiR-6778-5p belongs to the 5'-tail mirtron type of non-canonical miRNAs and is transcript splice-derived from intron 5 of SHMT1 (coding cytoplasmic serine hydroxymethyltransferase). It positively regulates expression of its host gene, SHMT1, via targeting YWHAE in Drosha-knockdown GC cells. Similar to its family member SHMT2, SHMT1 plays a crucial role in folate-dependent serine/glycine inter-conversion in one-carbon metabolism. In Drosha wild type GC cells, SHMT2 mediates a mitochondrial-carbon metabolic pathway, which is a major pathway of one-carbon metabolism in normal cells and most cancer cells. However, in Drosha-silenced or Drosha low-expressing GC cells, miR-6778-5p positively regulates SHMT1, instead of SHMT2, thus mediating a compensatory activation of cytoplasmic carbon metabolism that plays an essential role in the maintenance of CSCs in gastric cancer (GCSCs). Drosha wild type GCSCs with SHMT2 are sensitive to 5-fluorouracil; however, Drosha low-expressing GCSCs with SHMT1 are 5-FU-resistant. The loss of miR-6778-5p or SHMT1 notably mitigates GCSC sphere formation and increases sensitivity to 5-fluorouracil in Drosha-knockdown gastric cancer cells. Thus, our study reveals a novel function of Drosha-independent noncanonical miRNAs in maintaining the stemness of GCSCs.

Role and molecular mechanism of stem cells in colorectal cancer initiation

In recent years, the rate of colorectal cancer has sharply increased, especially in China, where it ranks second for the number of cancer fatalities. Currently, the treatment of colorectal cancer patients involves the combination of resection surgery and treatment with postoperative anticancer drugs such as 5-FU and oxaliplatin. However, recurrence and metastasis after treatment are still the dominant reasons for the low survival rate. Colorectal cancer stem cells (CSCs) are regarded as the key contributors to tumour recurrence and metastasis due to their resistance to chemotherapy drugs and their extremely high tumourigenicity. Once CSCs overcome chemotherapy treatment, they continue to survive and reinitiate proliferation to form tumours, leading to recurrence. The dominant reason for CSC resistance is that most anticancer drugs are aimed at inhibiting proliferative pathways in cancer cells that differ from those in CSCs. Therefore, studies on the characteristics of CSCs and their intracellular molecular pathways are essential for the exploration of CSC-targeted drugs. In this report, we review recent advances in the research of CSCs and, in particular, review the important intracellular molecular pathways, such as HOXA5-catenin, STRAP-NOTCH and YAP/TAZ, related to the maintenance and differentiation of stem cells to generate a theoretical basis for the exploration of CSC-targeted drugs.

Proton pump inhibitor: The dual role in gastric cancer

Proton pump inhibitors (PPIs) are one of the most frequently used medications for upper gastrointestinal diseases. However, a number of physicians have raised concern about the serious side effects of long-term use of PPIs, including the development of gastric cancer. Recent epidemiological studies have reported a significant association between long-term PPI intake and the risk of gastric cancer, even after successful Helicobacter pylori eradication. However, the effects of PPIs on the development of pre-malignant conditions such as atrophic gastritis or intestinal metaplasia are not fully known, suggesting the need for comprehensive and confirmative studies are needed in the future. Meanwhile, several experimental studies have demonstrated the effects of PPIs in reducing chemoresistance in gastric cancer cells by modulating the acidic microenvironment, cancer stemness and signal transducer and activator of transcription 3 (STAT3) signaling pathway. The inhibitory effects of PPIs on STAT3 activity may overcome drug resistance and enhance the efficacy of conventional or targeted chemotherapeutic agents. Taken together, PPIs may “play dual role” in gastric carcinogenesis and treatment of gastric cancer.

[Chloroquine induces apoptosis of human hepatocellular carcinoma cells in vitro by miR-26b-mediated regulation of Mcl-1]

OBJECTIVE

To investigate the effect of chloroquine in inducing apoptosis of human hepatocellular carcinoma cells and explore the possible mechanism.

METHODS

MTT assay and flow cytometry were used to evaluate chloroquine-induced growth inhibition and apoptosis in human hepatocellular carcinoma HepG2 cells, respectively. The ATP levels in chloroquine-treated cells were detected using an ATP assay kit. PCR and Western blotting were used to detect the expression levels of miR-26b and Mcl-1 in the cells, respectively.

RESULTS

Chloroquine inhibited the proliferation of HepG2 cells in a time- and concentration-dependent manner. Treatments with 80 µmol/L chloroquine for 24, 48, and 72 h induced survival rates of (71.59∓0.2)%, (45.40∓0.5)%, and (26.34∓1.4)% in the cells. Treatments with chloroquine at 40, 80, and 160 µmol/L for 5 h resulted in obviously lowered intracellular ATP levels in the cells to 87.80%, 71.29%, and 38.02% of the control level, respectively. At 80 µmol/L, chloroquine significantly increased the expression of miR-26b and down-regulated the expression of Mcl-1 in HepG2 cells, and the application of the miR-26b inhibitor increased the cellular expression of Mcl-1.

CONCLUSION

s Chloroquine can inhibit the cell proliferation, reduce ATP level and induce apoptosis in HepG2 cells possibly through miR-26b-mediated regulation of Mcl-1.