Cinnamaldehyde enhances apoptotic effect of oxaliplatin and reverses epithelial-mesenchymal transition and stemnness in hypoxic colorectal cancer cells

Apigenin 7-glucoside impedes hypoxia-induced malignant phenotypes of cervical cancer cells in a p16-dependent manner

Apigenin 7-glucoside (A7G) can suppress cell proliferation and trigger apoptosis in cervical cancer cells. Considering that hypoxia is associated with the malignant phenotypes in cervical cancer, this study aimed to uncover whether A7G exhibits suppressive effects on the hypoxia-induced malignant phenotype of cervical cancer cells (HeLa cells). Compared to normoxia, hypoxia can enhance the malignant phenotypes of HeLa cells, including cell proliferation, reduced sensitivity against chemotherapeutic agents (oxaliplatin and paclitaxel), cancer stemness, migration, and invasion. A7G intervention (20, 40, and 60 μM) could impair these malignant phenotypes of HeLa cells and upregulate the expression level of total and nuclear p16 proteins. Molecular docking analysis showed the interaction between anion exchanger 1 and A7G. In p16-silencing HeLa cells, the anticancer effects of A7G were absent. Therefore, hypoxia derives malignant phenotypes of HeLa cells, which could be impeded by A7G in a p16-dependent manner.

Unraveling the function of epithelial-mesenchymal transition (EMT) in colorectal cancer: Metastasis, therapy response, and revisiting molecular pathways

Colorectal cancer (CRC) is a dangerous form of cancer that affects the gastrointestinal tract. It is a major global health concern, and the aggressive behavior of tumor cells makes it difficult to treat, leading to poor survival rates for patients. One major challenge in treating CRC is the metastasis, or spread, of the cancer, which is a major cause of death. In order to improve the prognosis for patients with CRC, it is necessary to focus on ways to inhibit the cancer's ability to invade and spread. Epithelial-mesenchymal transition (EMT) is a process that is linked to the spread of cancer cells, also known as metastasis. The process transforms epithelial cells into mesenchymal ones, increasing their mobility and ability to invade other tissues. This has been shown to be a key mechanism in the progression of colorectal cancer (CRC), a particularly aggressive form of gastrointestinal cancer. The activation of EMT leads to increases in the spread of CRC cells, and during this process, levels of the protein E-cadherin decrease while levels of N-cadherin and vimentin increase. EMT also contributes to the development of resistance to chemotherapy and radiation therapy in CRC. Non-coding RNAs, such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), play a role in regulating EMT in CRC, often through their ability to "sponge" microRNAs. Anti-cancer agents have been shown to suppress EMT and reduce the progression and spread of CRC cells. These findings suggest that targeting EMT or related mechanisms may be a promising approach for treating CRC patients in the clinic.

Research progress of traditional Chinese medicine as sensitizer in reversing chemoresistance of colorectal cancer

In recent years, the incidences and mortalities from colorectal cancer (CRC) have been increasing; therefore, there is an urgent need to discover newer drugs that enhance drug sensitivity and reverse drug tolerance in CRC treatment. With this view, the current study focuses on understanding the mechanism of CRC chemoresistance to the drug as well as exploring the potential of different traditional Chinese medicine (TCM) in restoring the sensitivity of CRC to chemotherapeutic drugs. Moreover, the mechanism involved in restoring sensitivity, such as by acting on the target of traditional chemical drugs, assisting drug activation, increasing intracellular accumulation of anticancer drugs, improving tumor microenvironment, relieving immunosuppression, and erasing reversible modification like methylation, have been thoroughly discussed. Furthermore, the effect of TCM along with anticancer drugs in reducing toxicity, increasing efficiency, mediating new ways of cell death, and effectively blocking the drug resistance mechanism has been studied. We aimed to explore the potential of TCM as a sensitizer of anti-CRC drugs for the development of a new natural, less-toxic, and highly effective sensitizer to CRC chemoresistance.

Mitochondria-Targeting Polyprodrugs to Overcome the Drug Resistance of Cancer Cells by Self-Amplified Oxidation-Triggered Drug Release

The multi-drug resistance (MDR) of cancers is one of the main barriers for the success of diverse chemotherapeutic methods and is responsible for most cancer deaths. Developing efficient approaches to overcome MDR is still highly desirable for efficient chemotherapy of cancers. The delivery of targeted anticancer drugs that can interact with mitochondrial DNA is recognized as an effective strategy to reverse the MDR of cancers due to the relatively weak DNA-repairing capability in the mitochondria. Herein, we report on a polyprodrug that can sequentially target cancer cells and mitochondria using folic acid (FA) and tetraphenylphosphonium (TPP) targeting moieties, respectively. They were conjugated to the terminal groups of the amphiphilic block copolymer prodrugs composed of poly[oligo(ethylene glycol) methyl ether methacrylate] (POEGMA) and copolymerized monomers containing cinnamaldehyde (CNM) and doxorubicin (DOX). After self-assembly into micelles with the suitable size (∼30 nm), which were termed as TF@CNM + DOX, and upon intravenous administration, the micelles can accumulate in tumor tissues. After FA-mediated endocytosis, the endosomal acidity (∼pH 5) can trigger the release of CNM from TF@CNM + DOX micelles, followed by enhanced accumulation into the mitochondria via the TPP target. This promotes the overproduction of reactive oxygen species (ROS), which can subsequently enhance the intracellular oxidative stress and trigger ROS-responsive release of DOX into the mitochondria. TF@CNM + DOX shows great potential to inhibit the growth of DOX-resistant MCF-7 ADR tumors without observable side effects. Therefore, the tumor and mitochondria dual-targeting polyprodrug design represents an ideal strategy to treat MDR tumors through improvement of the intracellular oxidative level and ROS-responsive drug release.

Supercritical fluid extract of Angelica sinensis promotes the anti-colorectal cancer effect of oxaliplatin

Oxaliplatin-based chemotherapy regimens are recommended for patients with advanced colorectal cancer (CRC). However, oxaliplatin (OXA) can cause toxic side effects at the recommended dosage. Therefore, it is necessary to find new drug candidates that can synergize with OXA and thereby lower the OXA dose while still maintaining its efficacy. Angelica sinensis is a common drug in traditional Chinese medicine and has demonstrated a significant anti-CRC effect in modern pharmacological studies. The active ingredients in Angelica sinensis can be effectively extracted by a supercritical fluid extract. In this study, the supercritical fluid extract of Angelica sinensis (A-SFE) was obtained by a stable extraction process and was chemically characterized by GC/MS. The anti-cancer effect of A-SFE when applied individually was explored in vitro through MTT, scratch, and Transwell assay. The effect of A-SFE on CRC cells under the influence of tumor-associated macrophages (TAMs) was explored by a co-culture model. The results showed that A-SFE could inhibit the viability, metastasis, and invasion of HCT116 cells, especially under the influence of TAMs. When 20–100 μg/ml of A-SFE and 8–64 μg/ml of OXA were used in combination in HCT116 cells, synergistic or additive effects were shown in different concentration combinations. The CT26 syngeneic mouse model was used to explore the anti-CRC effect of OXA combined with A-SFE in vivo. The tumor volume, expression levels of Ki67, MMP9, and CD206 in the OXA + A-SFE group were less than those in the OXA group. In conclusion, A-SFE has the potential to become an adjuvant drug for OXA in the treatment of CRC, which provides new strategies for anti-colorectal cancer research.

Cinnamaldehyde Suppressed EGF-Induced EMT Process and Inhibits Ovarian Cancer Progression Through PI3K/AKT Pathway

Ovarian cancer is one of the most common gynecological malignancies in women worldwide with a poor survival rate. Cinnamaldehyde (CA), a bioactive substance isolated from cinnamon bark, is a natural drug and has shown that it can inhibit the progression of other tumors. However, the role of CA in ovarian cancer and its mechanism is poorly understood. In this study, wound healing assays, plate cloning, CCK-8, and transwell assays were used to determine cell proliferation and invasion. Western blot and flow cytometry were used to detect apoptosis levels. Western blot and immunofluorescence were used to detect changes in cellular EMT levels. The Western blot was used to detect levels of the PI3K/AKT signaling pathway. In vivo, we established a subcutaneous transplantation tumor model in nude mice to verify the role of CA in the progression and metastasis of ovarian cancer. Our data showed that in vitro CA was able to inhibit the cell viability of ovarian cancer. The results of scratch assay and transwell assay also showed that CA inhibited the proliferation and invasion ability of A2780 and SKOV3 cells. In addition, CA promoted apoptosis by increasing the expression of cleaved-PARP and cleaved-caspase 3 in ovarian cancer cells. Mechanistically, we found that CA inhibited the EGF-induced PI3K/AKT signaling pathway and reduced the phosphorylation levels of mTOR, PI3K, and AKT. The EGF-induced EMT process was also abolished by CA. The EMT process induced by AKT-specific activator SC79 was also suppressed by CA. Furthermore, in in vivo, CA significantly repressed the progression of ovarian cancer as well as liver metastasis. In all, our results suggest that CA inhibits ovarian cancer progression and metastasis in vivo and in vitro and inhibits EGF-induced EMT processes through the PI3K/AKT signaling pathway.

Cinnamaldehyde Relieves Induced Hepatocellular Carcinoma in Rat Model via Targeting Wnt/β-Catenin Pathway

Cinnamaldehyde (CA) is a natural compound that has promising biological activity. The current study investigates the antitumor activity of CA in thioacetamide induced hepatocellular carcinoma (HCC) in rats through targeting the Wnt/β-catenin pathway and evaluates the capability of CA to relieve hepatocytes oxidative stress in the HCC-rat model. After 16 weeks of HCC induction by thioacetamide (TAA), rats were treated for 7 consecutive weeks with CA daily; i.p. injection, Alpha-fetoprotein (AFP) level, necroinflammatory score and fibrosis percentage were measured to assess HCC development. The Wnt/β-catenin pathway was evaluated by measuring the hepatic protein level of Wnt-3a, β-catenin, cyclin D, matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor (VEGF). Furthermore, hepatocytes’ oxidative stress was assessed by measuring hepatic GSH and MDA contents. Results showed that CA was significantly inhibiting the Wnt/β-catenin pathway through the downregulation of hepatic Wnt-3a, β-catenin, cyclin D, MMP-9, and VEGF. Moreover, CA ameliorates hepatocytes’ oxidative stress via lowering hepatic MDA content and rising hepatic GSH content. Thus, in conclusion, CA is a promising treatment for HCC. It not only has an effective antitumor activity but also ameliorates hepatocytes’ oxidative stress.

Combinatorial Effects of the Natural Products Arctigenin, Chlorogenic Acid, and Cinnamaldehyde Commit Oxidation Assassination on Breast Cancer Cells

Major obstacles in current breast cancer treatment efficacy include the ability of breast cancer cells to develop resistance to chemotherapeutic drugs and the off-target cytotoxicity of these drugs on normal cells, leading to debilitating side effects. One major difference between cancer and normal cells is their metabolism, as cancer cells acquire glycolytic and mitochondrial metabolism alterations throughout tumorigenesis. In this study, we sought to exploit this metabolic difference by investigating alternative breast cancer treatment options based on the application of phytochemicals. Herein, we investigated three phytochemicals, namely cinnamaldehyde (CA), chlorogenic acid (CGA), and arctigenin (Arc), regarding their anti-breast-cancer properties. These phytochemicals were administered alone or in combination to MCF-7, MDA-MB-231, and HCC1419 breast cancer or normal MCF-10A and MCF-12F breast cells. Overall, our results indicated that the combination treatments showed stronger inhibitory effects on breast cancer cells versus single treatments. However, only treatments with CA (35 μM), CGA (250 μg/mL), and the combination of CA + CGA (35 μM + 250 μg/mL) showed no significant cytotoxic effects on normal mammary epithelial cells, suggesting that Arc was the driver of normal cell cytotoxicity in all other treatments. CA + CGA and, to a lesser extent, CGA alone effectively induced breast cancer cell death accompanied by decreases in mitochondrial membrane potential, increased mitochondrial superoxide, reduced mitochondrial and glycolytic ATP production, and led to significant changes in cellular and mitochondrial morphology. Altogether, the combination of CA + CGA was determined as the best anti-breast-cancer treatment strategy due to its strong anti-breast-cancer effects without strong adverse effects on normal mammary epithelial cells. This study provides evidence that targeting the mitochondria may be an effective anticancer treatment, and that using phytochemicals or combinations thereof offers new approaches in treating breast cancer that significantly reduce off-target effects on normal cells.

Cinnamaldehyde Downregulation of Sept9 Inhibits Glioma Progression through Suppressing Hif-1α via the Pi3k/Akt Signaling Pathway

Purpose

Cinnamaldehyde (CA) is the main ingredient in cinnamon, and it has been proven to have an inhibitory effect on many different tumor types. However, it lacks effect on glioma. This paper explores the effect CA has on glioma cells U87 and U251 at the cellular and molecular levels.

Methods

The relationship between Hif-1α and Sept9 was found by CGGA. Cell Viability Assay (CCK8) was made to detect the proliferation ability. The scratch experiment and the transwell experiment were applied to the migration and invasion ability. Annexin V-FITC/PI were used to detect the cell apoptosis. Western blotting was used to determine the specified protein level.

Results

Cell proliferation assay results revealed CA to inhibit the proliferation of glioma cells in a dose-dependent manner. It promoted apoptosis for upregulating the expression of Bax and downregulating the expression of Bcl-2. Wound Healing Assay and transwell test found CA to have anti-invasion ability and that it upregulated the expression of E-cadherin and downregulated the expressions of MMP-2 and MMP-9. The molecular mechanism was studied from a tumor microenvironment (TME) perspective. Pi3k inhibitor (LY294002) was used for interfering with cells, and the results found CA to demonstrate a similar effect. Hif-1α and Sept9 expressions were inhibited, and Akt and p-Akt were also inhibited. By using CoCl₂ to make hypoxia, CA was discovered to inhibit the high expression of Hif-1α and Sept9, demonstrating a correlation with the Pi3k/Akt pathway. It is suggested that the mechanism of Sept9 under hypoxia regulation can be realized through the Pi3k/Akt pathway.

Conclusions

This study proves for the first time that CA is an effective drug for inhibiting the proliferation of glioma through Sept9 and reveals Sept9 to be related to the Pi3k/Akt pathway in terms of tumor microenvironment, providing a molecular basis for the further study of CA in glioma treatment.

The Potential for Natural Products to Overcome Cancer Drug Resistance by Modulation of Epithelial-Mesenchymal Transition

The acquisition of resistance and ultimately disease relapse after initial response to chemotherapy put obstacles in the way of cancer therapy. Epithelial-mesenchymal transition (EMT) is a biologic process that epithelial cells alter to mesenchymal cells and acquire fibroblast-like properties. EMT plays a significant role in cancer metastasis, motility, and survival. Recently, emerging evidence suggested that EMT pathways are very important in making drug-resistant involved in cancer. Natural products are gradually emerging as a valuable source of safe and effective anticancer compounds. Natural products could interfere with the different processes implicated in cancer drug resistance by reversing the EMT process. In this review, we illustrate the molecular mechanisms of EMT in the emergence of cancer metastasis. We then present the role of natural compounds in the suppression of EMT pathways in different cancers to overcome cancer cell drug resistance and improve tumor chemotherapy. HighlightsDrug-resistance is one of the obstacles to cancer treatment.EMT signaling pathways have been correlated to tumor invasion, metastasis, and drug-resistance.Various studies on the relationship between EMT and resistance to chemotherapy agents were reviewed.Different anticancer natural products with EMT inhibitory properties and drug resistance reversal effects were compared.

Research Progress of Epithelial-mesenchymal Transition Treatment and Drug Resistance in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancies in the world that seriously affects human health. Activation of epithelial-mesenchymal transition (EMT) is a physiological phenomenon during embryonic development that is essential for cell metastasis. EMT participates in various biological processes associated with trauma repair, organ fibrosis, migration, metastasis, and infiltration of tumor cells. EMT is a new therapeutic target for CRC; however, some patients with CRC develop resistance to some drugs due to EMT. This review focuses specifically on the status of treatments that target the EMT process and its role in the therapeutic resistance observed in patients with CRC.

Hypoxia effects on cancer stem cell phenotype in colorectal cancer: a mini-review

Colorectal cancer (CRC) is ranked third most incident and second most deadly around the world, and even though treatments significantly developed over the years, overall survival remains low. This scenario has the contribution of cancer stem cells (CSC), a subpopulation of the heterogeneous tumor bulk, considered to be responsible for the tumor maintenance, conventional therapies resistance, metastasis, and recurrence. In this regard, hypoxia appears as an important component of tumor microenvironment and CSC niche, being associated with a worse prognosis. Therefore, it is vital the study of hypoxia influence on CSC phenotype in CRC. The aim of this mini-review article is to present a brief overview on this field. Recent articles discoursed about CSC molecular regulation, signalling pathways, methods for the study of the topic, as well as molecules and drugs capacity of inhibiting the interplay of hypoxia-CSC. Finally, the studies demonstrated important results, extensively accessing the topics of cellular and molecular regulation and therapeutic intervention, being morphology an area to be more explored.

Potential Role of Traditional Chinese Medicines by Wnt/β-Catenin Pathway Compared With Targeted Small Molecules in Colorectal Cancer Therapy

Colorectal cancer (CRC) has become a global public health problem because of its high incidence and mortality rate worldwide. The previous clinical treatment for CRC mainly involves conventional surgery, chemotherapy, and radiotherapy. With the development of tumor molecular targeted therapy, small molecule inhibitors present a great advantage in improving the survival of patients with advanced CRC. However, various side effects and drug resistance induced by chemotherapy are still the major obstacles to improve the clinical benefit. Thus, it is crucial to find new and alternative drugs for CRC treatment. Traditional Chinese medicines (TCMs) have been proved to have low toxicity and multi-target characteristics. In the last few decades, an increasing number of studies have demonstrated that TCMs exhibit strong anticancer effects in both experimental and clinical models and may serve as alternative chemotherapy agents for CRC treatment. Notably, Wnt/β-catenin signaling pathway plays a vital role in the initiation and progression of CRC by modulating the stability of β-catenin in the cytoplasm. Targeting Wnt/β-catenin pathway is a novel direction for developing therapies for CRC. In this review, we outlined the anti-tumor effects of small molecular inhibitors on CRC through Wnt/β-catenin pathway. More importantly, we focused on the potential role of TCMs against tumors by targeting Wnt/β-catenin signaling at different stages of CRC, including precancerous lesions, early stage of CRC and advanced CRC. Furthermore, we also discussed perspectives to develop potential new drugs from TCMs via Wnt/β-catenin pathway for the treatment of CRC.

Targets and Mechanism Used by Cinnamaldehyde, the Main Active Ingredient in Cinnamon, in the Treatment of Breast Cancer

Background: Breast cancer has become one of the most common malignant tumors in women owing to its increasing incidence each year. Clinical studies have shown that Cinnamomum cassia (L.) J. Presl (cinnamon) has a positive influence on the prevention and treatment of breast cancer.

Aim: We aimed to screen the potential targets of cinnamon in the treatment of breast cancer through network pharmacology and explore its potential therapeutic mechanism through cell experiments.

Methods: We used the TCMSP, TCM Database @ Taiwan, and TCMID websites and established the active ingredient and target database of cinnamon. Thereafter, we used the GeneCards and OMIM databases to establish a breast cancer-related target database, which matched the cinnamon target database. Based on the matching results, the STRING database was used to analyze the interaction between the targets, and the biological information annotation database was used to analyze the biological process of the target (gene ontology) and the pathway enrichment of Kyoto Encyclopedia of Genes and Genomes (KEGG). After establishing the layout of the analysis, we used Cytoscape 3.6.0 software for network analysis. Finally, the cell experiment was used to verify the anti-breast cancer effect of cinnamaldehyde.

Results: Our research showed that the main components of cinnamon, including cinnamaldehyde, can play a role in the treatment of breast cancer through 59 possible important targets. Subsequently, enrichment analysis by gene ontology and Kyoto Encyclopedia of Genes and Genomes showed that 83 cell biological processes and 37 pathways were associated with breast cancer (p < 0.05), including the peroxisome proliferator-activated receptor and PI3K-Akt pathway, which are closely related to tumor cell apoptosis. In vitro cell verification experiments showed that cinnamaldehyde can significantly inhibit cell proliferation, change cell morphology, inhibit cell migration and invasion ability, and promote cell apoptosis.

Conclusion: Our results showed that cinnamaldehyde is a potential novel drug for the treatment and prevention of breast cancer.

In-situ reactive heat breaking cell wall by SO3 hydration: innovative cell-wall breaking technique to enhance extraction of cinnamaldehyde from cinnamon

Cinnamaldehyde (CA) is one of the major active pharmaceutical ingredient of cinnamon bark. Hydrodistillation (HD) is usually used in CA extraction, however, the extraction yield is lower. The cell wall is a key factor limiting the extraction of essential oils. In-situ reactive heat breaking cell wall (RHB) could destroy the cell wall, which was conducive to the diffusion of CA. The aim of this work was to examine the effect of RHB pretreatment to HD extraction. Response surface methodology (RSM) was used to optimize RHB pretreatment parameters, and Box-Behnken Design (BBD) method was performed to evaluate the effects of different operating parameters. The maximum yield was increased to 3.31 ± 0.11% (w/w) from 2.08 ± 0.042% (w/w) after RSM optimization. Scanning electron microscopic (SEM) analysis showed that RHB destroyed and disrupted the cell wall of cinnamon bark. The GC analysis demonstrated that the purity of cinnamaldehyde was improved and no new components were presented in the extraction product from the cinnamon via RHB pretreatment. In conclusion, RHB is an effective pretreatment method for the CA extraction, and also may be used in the other herbal medicine extraction.

Wnt/β‑catenin signaling: Causes and treatment targets of drug resistance in colorectal cancer (Review)

Colorectal cancer (CRC) is the third most common malignant tumor in humans. Chemotherapy is used for the treatment of CRC. However, the effect of chemotherapy remains unsatisfactory due to drug resistance. Growing evidence has shown that the presence of highly metastatic tumor stem cells, regulation of non-coding RNAs and the tumor microenvironment contributes to drug resistance mechanisms in CRC. Wnt/β-catenin signaling mediates the chemoresistance of CRC in these three aspects. Therefore, the present study analyzed the abundant evidence of the contribution of Wnt/β-catenin signaling to the development of drug resistance in CRC and discussed its possible role in improving the chemosensitivity of CRC, which may provide guidelines for its clinical treatment.

The modulatory effects of cinnamaldehyde on uric acid level and IL-6/JAK1/STAT3 signaling as a promising therapeutic strategy against benign prostatic hyperplasia

Benign prostatic hyperplasia (BPH) is a widespread disorder in elderly men. Cinnamaldehyde, which is a major constituent in the essential oil of cinnamon, has been previously reported to reduce xanthine oxidase activity, in addition to its anti-inflammatory, anti-oxidant, and anti-proliferative activities. Our study was designed to investigate the potential modulatory effects of cinnamaldehyde on testosterone model of BPH in rats through reduction of uric acid level, and suppression of IL-6/JAK1/STAT3 signaling pathway. Cinnamaldehyde (40 and 75 mg/kg) was orally administered to male Wistar rats for 3 weeks, and concurrently with testosterone (3 mg/kg, s.c.) from the second week. Cinnamaldehyde ameliorated the elevation in prostatic weight and index compared to rats treated with testosterone only, that was also confirmed by alleviation of histopathological changes in prostate architecture. The protective mechanisms of cinnamaldehyde were elucidated through inhibition of xanthine oxidase activity and reduced uric acid level. That was accompanied by reduction of the pro-inflammatory cytokines; interleukin-6 (IL-6), IL-1β, tumor necrosis factor-alpha (TNF-α), and the nuclear translocation of the transcription factor NF-κB p65, that could be attributed also to the enhanced anti-oxidant defense by cinnamaldehyde. The protein expression of JAK1, which is IL-6 receptor linked protein, was reduced with subsequently reduced activation of STAT3 protein. That eventually suppressed the formation of the proliferation protein cyclin D1, while elevated Bax/Bcl2 ratio. It can be concluded that reducing uric acid level through xanthine oxidase inhibition and suppression of the inflammatory signaling cascade; IL-6/JAK1/STAT3; by cinnamaldehyde could be a novel and promising therapeutic approach against BPH.

Hypoxia-mediated cancer stem cell resistance and targeted therapy

Drug resistance is a major obstacle in the treatment of tumors, which easily lead to relapse or poor prognosis. Cancer stem cells (CSCs) are regarded as one of the important targets that mediate tumor resistance. Increasing evidence shows that the tumor hypoxia microenvironment is closely related to the resistance of CSCs to chemotherapy and radiotherapy. In this review, we intend to review the articles that have described how the hypoxic microenvironment affects CSC stemness and mediates tumor resistance and provide new directions and methods in the clinical treatment of tumors. Here, we also discuss the feasibility and development prospects of using hypoxia-inducible factors (HIFs) that regulate the hypoxic microenvironment of tumors as targeted agents to treat tumors, as well as to reduce or even reverse the resistance of tumors to chemotherapy and radiotherapy.