Comparison of Colorectal Cancer Stem Cells and Oxaliplatin-Resistant Cells Unveils Functional Similarities

Astragali Radix-Curcumae Rhizoma herb pair reduces the stemness of colorectal cancer cells through HIF-2α/β-catenin pathway

BACKGROUND

Colorectal cancer (CRC) is one of the most common causes of cancer-related mortality and significantly impairs quality of life. Astragali Radix-Curcumae Rhizoma (AC) is widely employed in the treatment of CRC in Chinese medicine, but the precise mechanisms remain unclear.

PURPOSE

This study aimed to elucidate the mechanisms by which AC inhibits CRC progression.

METHODS

The active components of AC were identified using UPLC-MS/MS analysis. An orthotopic transplantation colorectal tumor model was established in BALB/c mice using the CT26-Lucifer cell line to evaluate the effects of AC. Tumor volumes were monitored using IVIS imaging technology. Histological examination of tumor morphology was performed with hematoxylin and eosin (H&E) staining. Transcriptomic sequencing of mouse tumor samples was conducted to identify critical pathways and molecular targets. The impact of AC on cell viability and migration was assessed using CCK-8 and wound healing assays, respectively. To investigate the effects of AC on CRC cells, an in vitro hypoxic model was established using cobalt chloride (CoCl2), a hypoxia inducer. HIF-2α overexpression was achieved by constructing stable lentiviral vectors. Key targets identified from RNA-seq, such as c-Myc, Ki-67, β-catenin, cleaved caspase 3, CD133, and CD44, were evaluated using western blotting, qRT-PCR, and immunofluorescence assays. Epithelial-Mesenchymal Transition (EMT) and spheroid cloning assays were employed to evaluate phenotypic changes in cancer stem cells.

RESULTS

Twelve components of AC were identified. AC effectively inhibited CRC progression in vivo. Transcriptomic analysis highlighted hypoxic signaling as a significantly enriched pathway, implicating its role in suppressing CRC progression by AC. In the hypoxic model, AC inhibited the proliferation and migration of CRC cells in vitro. Furthermore, AC reduced cancer stemness by downregulating stemness markers, inhibiting EMT, and decreasing tumor sphere formation. The downregulation of hypoxic responses and the shift in stemness by AC involved attenuation of HIF-2α and WNT/β-catenin signaling.

CONCLUSION

This study provides the first evidence that AC reduces the stemness of CRC and the inhibition of the transition of CRC to stem-like cells by AC is closely related to the downregulation of the HIF-2α/β-catenin pathway, especially under hypoxic conditions.

Antibiotic use during radical surgery in stage I-III colorectal cancer: correlation with outcomes?

AIMS

Accumulating evidence indicates that the use of antibiotics (ATBs) in cancer patients is potentially correlated with patient prognosis. Interestingly, the use of these agents is not uncommon in colorectal cancer (CRC) patients during surgery; however, their prognostic value in the clinic has never been addressed.

MATERIALS AND METHODS

Data on ATB use during surgery, including the cumulative defined daily dose (cDDD) and the number of categories, were collected. Differences in the clinical data between the low and high cDDD subgroups and between subgroups with ≤ 4 and >4 categories. Additionally, the disease-free survival (DFS) and overall survival (OS) among these subgroups and the specific categories were compared. Finally, a Cox proportional hazard model was used to validate the risk factors for the outcome.

RESULTS

The number of categories, rather than the cDDD, was a significant predictor of both DFS (P = 0.043) and OS (P = 0.039). Patients with obstruction are more likely to have a high cDDD, whereas older patients are more likely to have multiple categories. There were no significant differences in the DFS (log rank = 1.36, P = 0.244) or OS (log rank = 0.40, P = 0.528) between patients in the low- and high-cDDD subgroups, whereas patients with ≤ 4 categories had superior DFS (log rank = 9.92, P = 0.002) and OS (log rank = 8.30, P = 0.004) compared with those with >4 categories. Specifically, the use of quinolones was harmful to survival (DFS: log rank = 3.67, P = 0.055; OS: log rank = 5.10, P = 0.024), whereas the use of macrolides was beneficial to survival (DFS: log rank = 12.26, P < 0.001; OS: log rank = 9.77, P = 0.002). Finally, the number of categories was identified as an independent risk factor for both DFS (HR = 2.05, 95% CI: 1.35-3.11, P = 0.001) and OS (HR = 1.82, 95% CI: 1.14-2.90, P = 0.012).

CONCLUSIONS

The cDDD of ATBs during surgery in stage I-III CRC patients did not correlate with outcome; however, patients in multiple categories or a specific category are likely to have inferior survival. These results suggest that particular caution should be taken when selecting ATBs for these patients in the clinic.

The rational modulation of autophagy sensitizes colorectal cancer cells to 5-fluouracil and oxaliplatin

Colorectal cancer (CRC) is the third most common and deadliest cancer globally. Regimens using 5-fluorouracil (5FU) and Oxaliplatin (OXA) are the first-line treatment for CRC, but tumor recurrence is frequent. It is plausible to hypothesize that differential cellular responses are triggered after treatments depending on the genetic background of CRC cells and that the rational modulation of cell tolerance mechanisms like autophagy may reduce the regrowth of CRC cells. This study proposes investigating the cellular mechanisms triggered by CRC cells exposed to 5FU and OXA using a preclinical experimental design mimicking one cycle of the clinical regimen (i.e., 48 h of treatment repeated every 2 weeks). To test this, we treated CRC human cell lines HCT116 and HT29 with the 5FU and OXA, combined or not, for 48 h, followed by analysis for two additional weeks. Compared to single-drug treatments, the co-treatment reduced tumor cell regrowth, clonogenicity and stemness, phenotypes associated with tumor aggressiveness and poor prognosis in clinics. This effect was exerted by the induction of apoptosis and senescence only in the co-treatment. However, a week after treatment, cells that tolerated the treatment had high levels of autophagy features and restored the proliferative phenotype, resembling tumor recurrence. The pharmacologic suppression of early autophagy during its peak of occurrence, but not concomitant with chemotherapeutics, strongly reduced cell regrowth. Overall, our experimental model provides new insights into the cellular mechanisms that underlie the response and tolerance of CRC cells to 5FU and OXA, suggesting optimized, time-specific autophagy inhibition as a new avenue for improving the efficacy of current treatments.

The E3 ligase HUWE1 increases the sensitivity of CRC to oxaliplatin through TOMM20 degradation

Continuous administration of oxaliplatin, the most widely used first-line chemotherapy drug for colorectal cancer (CRC), eventually leads to drug resistance. Increasing the sensitivity of CRC cells to oxaliplatin is a key strategy to overcome this issue. Impairment of mitochondrial function is a pivotal mechanism determining the sensitivity of CRC to oxaliplatin. We discovered an inverse correlation between Translocase of Outer Mitochondrial Membrane 20 (TOMM20) and oxaliplatin sensitivity as well as an inverse relationship between TOMM20 and HECT, UBA, and WWE domain containing E3 ligase 1 (HUWE1) expression in CRC. For the first time, we demonstrated that HUWE1 ubiquitinates TOMM20 directly and also regulates TOMM20 degradation via the PARKIN-mediated pathway. Furthermore, we showed that overexpression of HUWE1 in CRC cells has a negative effect on mitochondrial function, including the generation of ATP and maintenance of mitochondrial membrane potential, leading to increased production of ROS and apoptosis. This effect was amplified when cells were treated simultaneously with oxaliplatin. Our study conclusively shows that TOMM20 is a novel target of HUWE1. Our findings indicate that HUWE1 plays a critical role in regulating oxaliplatin sensitivity by degrading TOMM20 and inducing mitochondrial damage in CRC.

Cancer cell cycle heterogeneity as a critical determinant of therapeutic resistance

Intra-tumor heterogeneity is now arguably one of the most-studied topics in tumor biology, as it represents a major obstacle to effective cancer treatment. Since tumor cells are highly diverse at genetic, epigenetic, and phenotypic levels, intra-tumor heterogeneity can be assumed as an important contributing factor to the nullification of chemotherapeutic effects, and recurrence of the tumor. Based on the role of heterogeneous subpopulations of cancer cells with varying cell-cycle dynamics and behavior during cancer progression and treatment; herein, we aim to establish a comprehensive definition for adaptation of neoplastic cells against therapy. We discuss two parallel and yet distinct subpopulations of tumor cells that play pivotal roles in reducing the effects of chemotherapy: "resistant" and "tolerant" populations. Furthermore, this review also highlights the impact of the quiescent phase of the cell cycle as a survival mechanism for cancer cells. Beyond understanding the mechanisms underlying the quiescence, it provides an insightful perspective on cancer stem cells (CSCs) and their dual and intertwined functions based on their cell cycle state in response to treatment. Moreover, CSCs, epithelial-mesenchymal transformed cells, circulating tumor cells (CTCs), and disseminated tumor cells (DTCs), which are mostly in a quiescent state of the cell cycle are proved to have multiple biological links and can be implicated in our viewpoint of cell cycle heterogeneity in tumors. Overall, increasing our knowledge of cell cycle heterogeneity is a key to identifying new therapeutic solutions, and this emerging concept may provide us with new opportunities to prevent the dreadful cancer recurrence.

Oxaliplatin Enhances the Apoptotic Effect of Mesenchymal Stem Cells, Delivering Soluble TRAIL in Chemoresistant Colorectal Cancer

A key problem in colorectal cancer (CRC) is the development of resistance to current therapies due to the presence of cancer stem cells (CSC), which leads to poor prognosis. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a protein that activates apoptosis in cancer cells through union with TRAIL death receptors. Cell therapies as delivery systems can produce soluble TRAIL (sTRAIL) and full-length TRAIL (flTRAIL), showing a high capacity to produce apoptosis in vitro and in vivo assays. However, the apoptotic activity of TRAIL as monotherapy had limitations, so it is important to explore other ways to enhance susceptibility to TRAIL. This study evaluated the cytotoxic and proapoptotic activity of soluble TRAIL overexpressed by mesenchymal stem cells (MSC) in an oxaliplatin-resistant CRC cell line. Bone marrow-MSC were lentiviral transduced for soluble TRAIL expression. DR5 death receptor expression was determined in Caco-2 and CMT-93 CRC cell lines. Sensitivity to first-line chemotherapies and recombinant TRAIL was evaluated by half-maximal inhibitory concentrations. Cytotoxic and proapoptotic activity of soluble TRAIL-MSC alone and combined with chemotherapy pre-treatment was evaluated using co-cultures. Caco-2 and CMT-93 cell lines expressed 59.08 ± 5.071 and 51.65 ± 11.99 of DR5 receptor and had IC50 of 534.15 ng/mL and 581.34 ng/mL for recombinant murine TRAIL (rmTRAIL), respectively. This finding was classified as moderate resistance to TRAIL. The Caco-2 cell line showed resistance to oxaliplatin and irinotecan. MSC successfully overexpressed soluble TRAIL and induced cancer cell death at a 1:6 ratio in co-culture. Oxaliplatin pre-treatment in the Caco-2 cell line increased the cell death percentage (50%) and apoptosis by sTRAIL. This finding was statistically different from the negative control (p < 0.05), and activity was even higher with the oxaliplatin-flTRAIL combination. Thus, oxaliplatin increases apoptotic activity induced by soluble TRAIL in a chemoresistant CRC cell line.

Dihydroartemisinin inhibited stem cell-like properties and enhanced oxaliplatin sensitivity of colorectal cancer via AKT/mTOR signaling

Colorectal cancer (CRC) is a common tumor with high morbidity and mortality. The use of oxaliplatin (L-OHP) as a first-line treatment for CRC is limited due to chemoresistance. Growing evidence have revealed that the existence of cancer stem-like cells (CSLCs) is one of the important reasons for drug resistance and recurrence of cancers. Dihydroartemisinin (DHA), a derivative of artemisinin, has showed anticancer effects on a variety of malignancies, in addition to its antimalarial effects. However, the effect and mechanism of DHA on CSLCs and chemosensitivity in CRC cells remains unclear. In this study, we found that DHA inhibited cell viability in HCT116 and SW620 cells. Moreover, DHA decreased cell clonogenicity, and improved L-OHP sensitivity. Furthermore, DHA treatment attenuated tumor sphere formation, and the expressions of stem cell surface marker (CD133 and CD44) and stemness-associated transcription factor (Nanog, c-Myc, and OCT4). Mechanistically, the present findings showed that DHA inhibited of AKT/mTOR signaling pathway. The activation of AKT/mTOR signaling reversed DHA-decreased cell viability, clonogenicity, L-OHP resistance, tumor sphere, and expressions of stemness-associated protein in CRC. The inhibitory effect of DHA on tumorigenicity of CRC cells has also been demonstrated in BALB/c nude mice. In conclusion, this study revealed that DHA inhibited CSLCs properties in CRC via AKT/mTOR signaling, suggesting that DHA may be used as a potential therapeutic agent for CRC.

Implication of Different Tumor Biomarkers in Drug Resistance and Invasiveness in Primary and Metastatic Colorectal Cancer Cell Lines

Protein expression profiles are directly related to the different properties of cells and are conditioned by the cellular niche. As an example, they are the cause of the characteristic cell plasticity, epithelium-mesenchymal transition (EMT), and drug resistance of cancer cells. This article characterizes ten biomarkers related to these features in three human colorectal cancer cell lines: SW-480, SW-620, and DLD-1, evaluated by flow cytometry; and in turn, resistance to oxaliplatin is studied through dose-response trials. The main biomarkers present in the three studied lines correspond to EpCAM, CD-133, and AC-133, with the latter two in low proportions in the DLD-1 line. The biomarker CD166 is present in greater amounts in SW-620 and DLD-1 compared to SW-480. Finally, DLD-1 shows high values of Trop2, which may explain the aggressiveness and resistance of these cells to oxaliplatin treatments, as EpCAM is also highly expressed. Exposure to oxaliplatin slows cell growth but also helps generate resistance to the treatment. In conclusion, the response of the cell lines is variable, due to their genetic variability, which will condition protein expression and cell growth. Further analyses in this area will provide important information for better understanding of patients' cellular response and how to prevent resistance.