Messing Up the Cancer Stem Cell Chemoresistance Mechanisms Supported by Tumor Microenvironment

Targeting hyaluronan metabolism-related molecules associated with resistant tumor-initiating cells potentiates chemotherapy efficacy in lung cancer

The success of chemotherapy regimens in patients with non-small cell lung cancer (NSCLC) could be restricted at least in part by cancer stem cells (CSC) niches within the tumor microenvironment (TME). CSC express CD133, CD44, CD47, and SOX2, among other markers and factors. Analysis of public data revealed that high expression of hyaluronan (HA), the main glycosaminoglycan of TME, correlated positively with CSC phenotype and decreased disease-free interval in NSCLC patients. We aimed to cross-validate these findings on human and murine lung cancer cells and observed that CD133 + CSC differentially expressed higher levels of HA, HAS3, ABCC5, SOX2, and CD47 (p < 0.01). We modulated HA expression with 4-methylumbelliferone (4Mu) and detected an increase in sensitivity to paclitaxel (Pa). We evaluated the effect of 4Mu + chemotherapy on survival, HA metabolism, and CSC profile. The combination of 4Mu with Pa reduced the clonogenic and tumor-forming ability of CSC. Pa-induced HAS3, ABCC5, SOX2, and CD47 expression was mitigated by 4Mu. Pa + 4Mu combination significantly reduced in vivo tumor growth, enhancing animal survival and restoring the CSC profile in the TME to basal levels. Our results suggest that HA is involved in lung CSC phenotype and chemosensitivity, and its modulation by 4Mu improves treatment efficacy to inhibit tumor progression.

Overcoming Chemoresistance in Cancer: The Promise of Crizotinib

Chemoresistance is a major obstacle in cancer treatment, often leading to disease progression and poor outcomes. It arises through various mechanisms such as genetic mutations, drug efflux pumps, enhanced DNA repair, and changes in the tumor microenvironment. These processes allow cancer cells to survive despite chemotherapy, underscoring the need for new strategies to overcome resistance and improve treatment efficacy. Crizotinib, a first-generation multi-target kinase inhibitor, is approved by the FDA for the treatment of ALK-positive or ROS1-positive non-small cell lung cancer (NSCLC), refractory inflammatory (ALK)-positive myofibroblastic tumors (IMTs) and relapsed/refractory ALK-positive anaplastic large cell lymphoma (ALCL). Crizotinib exists in two enantiomeric forms: (R)-crizotinib and its mirror image, (S)-crizotinib. It is assumed that the R-isomer is responsible for the carrying out various processes reviewed here The S-isomer, on the other hand, shows a strong inhibition of MTH1, an enzyme important for DNA repair mechanisms. Studies have shown that crizotinib is an effective multi-kinase inhibitor targeting various kinases such as c-Met, native/T315I Bcr/Abl, and JAK2. Its mechanism of action involves the competitive inhibition of ATP binding and allosteric inhibition, particularly at Bcr/Abl. Crizotinib showed synergistic effects when combined with the poly ADP ribose polymerase inhibitor (PARP), especially in ovarian cancer harboring BRCA gene mutations. In addition, crizotinib targets a critical vulnerability in many p53-mutated cancers. Unlike its wild-type counterpart, the p53 mutant promotes cancer cell survival. Crizotinib can cause the degradation of the p53 mutant, sensitizing these cancer cells to DNA-damaging substances and triggering apoptosis. Interestingly, other reports demonstrated that crizotinib exhibits anti-bacterial activity, targeting Gram-positive bacteria. Also, it is active against drug-resistant strains. In summary, crizotinib exerts anti-tumor effects through several mechanisms, including the inhibition of kinases and the restoration of drug sensitivity. The potential of crizotinib in combination therapies is emphasized, particularly in cancers with a high prevalence of the p53 mutant, such as triple-negative breast cancer (TNBC) and high-grade serous ovarian cancer (HGSOC).

An overview of current research on cancer stem cells: a bibliometric analysis

BACKGROUND

Cancer stem cells (CSCs) represent a potential mechanism contributing to tumorigenesis, metastasis, recurrence, and drug resistance. The objective of this study is to investigate the status quo and advancements in CSC research utilizing bibliometric analysis.

METHODS

Publications related to CSCs from 2010 to 2022 were collected from the Web of Science Core Collection database. Various analytical tools including CiteSpace, VOSviewer, Scimago Graphica, and GraphPad Prism were used to visualize aspects such as co-authorship, co-occurrence, and co-citation within CSC research to provide an objective depiction of the contemporary status and developmental trajectory of the CSC field.

RESULTS

A total of 22,116 publications were included from 1942 journals written by 95,992 authors. Notably, China emerged as the country with the highest number of publications, whereas the United States exerted the most significant influence within the field. MD Anderson Cancer Center emerged as the institution making the most comprehensive contributions. Wicha M.S. emerged as the most prolific and influential researcher. Among journals, Cancers emerged as a focal point for CSC research, consistently publishing a wealth of high-quality papers. Furthermore, it was observed that most journals tended to approach CSC research from molecular, biological, and immunological perspectives. The research into CSCs encompassed a broad array of topics, including isolation and enrichment techniques, biomarkers, biological characteristics, cancer therapy strategies, and underlying biological regulatory mechanisms. Notably, exploration of the tumor microenvironment and extracellular vesicles emerged as burgeoning research frontiers for CSCs.

CONCLUSION

The research on CSCs has garnered growing interest. A trend toward multidisciplinary homogeneity is emerging within the realm of CSCs. Further investigation could potentially center on the patients of extracellular vesicles and the tumor microenvironment in relation to CSCs.

Cancer metabolism and carcinogenesis

Metabolic reprogramming is an emerging hallmark of cancer cells, enabling them to meet increased nutrient and energy demands while withstanding the challenging microenvironment. Cancer cells can switch their metabolic pathways, allowing them to adapt to different microenvironments and therapeutic interventions. This refers to metabolic heterogeneity, in which different cell populations use different metabolic pathways to sustain their survival and proliferation and impact their response to conventional cancer therapies. Thus, targeting cancer metabolic heterogeneity represents an innovative therapeutic avenue with the potential to overcome treatment resistance and improve therapeutic outcomes. This review discusses the metabolic patterns of different cancer cell populations and developmental stages, summarizes the molecular mechanisms involved in the intricate interactions within cancer metabolism, and highlights the clinical potential of targeting metabolic vulnerabilities as a promising therapeutic regimen. We aim to unravel the complex of metabolic characteristics and develop personalized treatment approaches to address distinct metabolic traits, ultimately enhancing patient outcomes.

Improving targeted small molecule drugs to overcome chemotherapy resistance

BACKGROUND

Conventional cancer treatments face the challenge of therapeutic resistance, which causes poor treatment outcomes. The use of combination therapies can improve treatment results in patients and is one of the solutions to overcome this challenge. Chemotherapy is one of the conventional treatments that, due to the non-targeted and lack of specificity in targeting cancer cells, can cause serious complications in the short and long-term for patients by damaging healthy cells. Also, the employment of a wide range of strategies for chemotherapy resistance by cancer cells, metastasis, and cancer recurrence create serious problems to achieve the desired results of chemotherapy. Accordingly, targeted therapies can be used as a combination treatment with chemotherapy to both cause less damage to healthy cells, which as a result, they reduce the side effects of chemotherapy, and by targeting the factors that cause therapeutic challenges, can improve the results of chemotherapy in patients.

RECENT FINDINGS

Small molecules are one of the main targeted therapies that can be used for diverse targets in cancer treatment due to their penetration ability and characteristics. However, small molecules in cancer treatment are facing obstacles that a better understanding of cancer biology, as well as the mechanisms and factors involved in chemotherapy resistance, can lead to the improvement of this type of major targeted therapy.

CONCLUSION

In this review article, at first, the challenges that lead to not achieving the desired results in chemotherapy and how cancer cells can be resistant to chemotherapy are examined, and at the end, research areas are suggested that more focusing on them, can lead to the improvement of the results of using targeted small molecules as an adjunctive treatment for chemotherapy in the conditions of chemotherapy resistance and metastasis of cancer cells.

Purinergic system in cancer stem cells

Accumulating evidence supports the idea that cancer stem cells (CSCs) are those with the capacity to initiate tumors, generate phenotypical diversity, sustain growth, confer drug resistance, and orchestrate the spread of tumor cells. It is still controversial whether CSCs originate from normal stem cells residing in the tissue or cancer cells from the tumor bulk that have dedifferentiated to acquire stem-like characteristics. Although CSCs have been pointed out as key drivers in cancer, knowledge regarding their physiology is still blurry; thus, research focusing on CSCs is essential to designing novel and more effective therapeutics. The purinergic system has emerged as an important autocrine-paracrine messenger system with a prominent role at multiple levels of the tumor microenvironment, where it regulates cellular aspects of the tumors themselves and the stromal and immune systems. Recent findings have shown that purinergic signaling also participates in regulating the CSC phenotype. Here, we discuss updated information regarding CSCs in the purinergic system and present evidence supporting the idea that elements of the purinergic system expressed by this subpopulation of the tumor represent attractive pharmacological targets for proposing innovative anti-cancer therapies.

Exosomes as a Nano-Carrier for Chemotherapeutics: A New Era of Oncology

Despite the considerable advancements in oncology, cancer remains one of the leading causes of death worldwide. Drug resistance mechanisms acquired by cancer cells and inefficient drug delivery limit the therapeutic efficacy of available chemotherapeutics drugs. However, studies have demonstrated that nano-drug carriers (NDCs) can overcome these limitations. In this sense, exosomes emerge as potential candidates for NDCs. This is because exosomes have better organotropism, homing capacity, cellular uptake, and cargo release ability than synthetic NDCs. In addition, exosomes can serve as NDCs for both hydrophilic and hydrophobic chemotherapeutic drugs. Thus, this review aimed to summarize the latest advances in cell-free therapy, describing how the exosomes can contribute to each step of the carcinogenesis process and discussing how these nanosized vesicles could be explored as nano-drug carriers for chemotherapeutics.

Hypoxia-induced cancer cell reprogramming: a review on how cancer stem cells arise

Cancer stem cells are a subset of cells within the tumor that possess the ability to self-renew as well as differentiate into different cancer cell lineages. The exact mechanisms by which cancer stem cells arise is still not completely understood. However, current research suggests that cancer stem cells may originate from normal stem cells that have undergone genetic mutations or epigenetic changes. A more recent discovery is the dedifferentiation of cancer cells to stem-like cells. These stem-like cells have been found to express and even upregulate induced pluripotent stem cell markers known as Yamanaka factors. Here we discuss developments in how cancer stem cells arise and consider how environmental factors, such as hypoxia, plays a key role in promoting the progression of cancer stem cells and metastasis. Understanding the mechanisms that give rise to these cells could have important implications for the development of new strategies in cancer treatments and therapies.

DNA Repair and Therapeutic Strategies in Cancer Stem Cells

First-line cancer treatments successfully eradicate the differentiated tumour mass but are comparatively ineffective against cancer stem cells (CSCs), a self-renewing subpopulation thought to be responsible for tumour initiation, metastasis, heterogeneity, and recurrence. CSCs are thus presented as the principal target for elimination during cancer treatment. However, CSCs are challenging to drug target because of numerous intrinsic and extrinsic mechanisms of drug resistance. One such mechanism that remains relatively understudied is the DNA damage response (DDR). CSCs are presumed to possess properties that enable enhanced DNA repair efficiency relative to their highly proliferative bulk progeny, facilitating improved repair of double-strand breaks induced by radiotherapy and most chemotherapeutics. This can occur through multiple mechanisms, including increased expression and splicing fidelity of DNA repair genes, robust activation of cell cycle checkpoints, and elevated homologous recombination-mediated DNA repair. Herein, we summarise the current knowledge concerning improved genome integrity in non-transformed stem cells and CSCs, discuss therapeutic opportunities within the DDR for re-sensitising CSCs to genotoxic stressors, and consider the challenges posed regarding unbiased identification of novel DDR-directed strategies in CSCs. A better understanding of the DDR mediating chemo/radioresistance mechanisms in CSCs could lead to novel therapeutic approaches, thereby enhancing treatment efficacy in cancer patients.

Is the combination of immunotherapy with conventional chemotherapy the key to increase the efficacy of colorectal cancer treatment?

Colorectal cancer (CRC) is among the most prevalent and deadly neoplasms worldwide. According to GLOBOCAN predictions, its incidence will increase from 1.15 million CRC cases in 2020 to 1.92 million cases in 2040. Therefore, a better understanding of the mechanisms involved in CRC development is necessary to improve strategies focused on reducing the incidence, prevalence, and mortality of this oncological pathology. Surgery, chemotherapy, and radiotherapy are the main strategies for treating CRC. The conventional chemotherapeutic agent utilized throughout the last four decades is 5-fluorouracil, notwithstanding its low efficiency as a single therapy. In contrast, combining 5-fluorouracil therapy with leucovorin and oxaliplatin or irinotecan increases its efficiency. However, these treatments have limited and temporary solutions and aggressive side effects. Additionally, most patients treated with these regimens develop drug resistance, which leads to disease progression. The immune response is considered a hallmark of cancer; thus, the use of new strategies and methodologies involving immune molecules, cells, and transcription factors has been suggested for CRC patients diagnosed in stages III and IV. Despite the critical advances in immunotherapy, the development and impact of immune checkpoint inhibitors on CRC is still under investigation because less than 25% of CRC patients display an increased 5-year survival. The causes of CRC are diverse and include modifiable environmental factors (smoking, diet, obesity, and alcoholism), individual genetic mutations, and inflammation-associated bowel diseases. Due to these diverse causes, the solutions likely cannot be generalized. Interestingly, new strategies, such as single-cell multiomics, proteomics, genomics, flow cytometry, and massive sequencing for tumor microenvironment analysis, are beginning to clarify the way forward. Thus, the individual mechanisms involved in developing the CRC microenvironment, their causes, and their consequences need to be understood from a genetic and immunological perspective. This review highlighted the importance of altering the immune response in CRC. It focused on drugs that may modulate the immune response and show specific efficacy and contrasted with evidence that immunosuppression or the promotion of the immune response is the answer to generating effective treatments with combined chemotherapeutic drugs.

Targeting the KLF5-EphA2 axis can restrain cancer stemness and overcome chemoresistance in basal-like breast cancer

Ephrin type-A receptor 2 (EphA2) is a member of the tyrosine receptor kinases, a family of membrane proteins recognized as potential anticancer targets. EphA2 highly expressed in a variety of human cancers, playing roles in proliferation, migration, and invasion. However, whether and how EphA2 regulates basal-like breast cancer (BLBC) cell stemness and chemoresistance has not been revealed. Here, KLF5 was proven to be a direct transcription factor for EphA2 in BLBC cells, and its expression was positively correlated in clinical samples from breast cancer patients. The inflammatory factor TNF-α could promote BLBC cell stemness partially by activating the KLF5-EphA2 axis. Moreover, phosphorylation of EphA2 at S897 (EphA2 pS897) induced by TNF-α and PTX/DDP contributes to chemoresistance of BLBC. Furthermore, the EphA2 inhibitor ALW-II-41-27 could effectively reduce EphA2 pS897 and tumor cell stemness in vitro and significantly enhance the sensitivity of xenografts to the chemotherapeutic drugs PTX and DDP in vivo. Clinically, tumor samples from breast patients with less response to neoadjuvant chemotherapy showed a high level of EphA2 pS897 expression. In conclusion, KLF5-EphA2 promotes stemness and drug resistance in BLBC and could be a potential target for the treatment of BLBC.

Destroying the Shield of Cancer Stem Cells: Natural Compounds as Promising Players in Cancer Therapy

In a scenario where eco-sustainability and a reduction in chemotherapeutic drug waste are certainly a prerogative to safeguard the biosphere, the use of natural products (NPs) represents an alternative therapeutic approach to counteract cancer diseases. The presence of a heterogeneous cancer stem cell (CSC) population within a tumor bulk is related to disease recurrence and therapy resistance. For this reason, CSC targeting presents a promising strategy for hampering cancer recurrence. Increasing evidence shows that NPs can inhibit crucial signaling pathways involved in the maintenance of CSC stemness and sensitize CSCs to standard chemotherapeutic treatments. Moreover, their limited toxicity and low costs for large-scale production could accelerate the use of NPs in clinical settings. In this review, we will summarize the most relevant studies regarding the effects of NPs derived from major natural sources, e.g., food, botanical, and marine species, on CSCs, elucidating their use in pre-clinical and clinical studies.

Engineered multifunctional nanocarriers for controlled drug delivery in tumor immunotherapy

The appearance of chemoresistance in cancer is a major issue. The main barriers to conventional tumor chemotherapy are undesirable toxic effects and multidrug resistance. Cancer nanotherapeutics were developed to get around the drawbacks of conventional chemotherapy. Through clinical evaluation of thoughtfully developed nano delivery systems, cancer nanotherapeutics have recently offered unmatched potential to comprehend and combat drug resistance and toxicity. In different design approaches, including passive targeting, active targeting, nanomedicine, and multimodal nanomedicine combination therapy, were successful in treating cancer in this situation. Even though cancer nanotherapy has achieved considerable technological development, tumor biology complexity and heterogeneity and a lack of full knowledge of nano-bio interactions remain important hurdles to future clinical translation and commercialization. The recent developments and advancements in cancer nanotherapeutics utilizing a wide variety of nanomaterial-based platforms to overcome cancer treatment resistance are covered in this article. Additionally, an evaluation of different nanotherapeutics-based approaches to cancer treatment, such as tumor microenvironment targeted techniques, sophisticated delivery methods for the precise targeting of cancer stem cells, as well as an update on clinical studies are discussed. Lastly, the potential for cancer nanotherapeutics to overcome tumor relapse and the therapeutic effects and targeted efficacies of modern nanosystems are analyzed.

Quantitative high-throughput analysis of tumor infiltrating lymphocytes in breast cancer

In breast cancer (BC), the development of cancer immunotherapy including immune checkpoint inhibitors has progressed. Tumor infiltrating lymphocytes (TILs) is one of the important factors for an immune response between tumor cells and immune cells in the tumor microenvironment, and the presence of TILs has been identified as predictors of response to chemotherapy. However, because complex mechanisms underlies the crosstalk between immune cells and cancer cells, the relationship between immune profiles in the tumor microenvironment and the efficacy of the immune checkpoint blocked has been unclear. Moreover, in many cases of breast cancer, the quantitative analysis of TILs and immuno-modification markers in a single tissue section are not studied. Therefore, we quantified detailed subsets of tumor infiltrating lymphocytes (TILs) from BC tissues and compared among BC subtypes. The TILs of BC tissues from 86 patients were classified using multiplex immunohistochemistry and an artificial intelligence-based analysis system based on T-cell subset markers, immunomodification markers, and the localization of TILs. The levels of CD4/PD1 and CD8/PD1 double-positive stromal TILs were significantly lower in the HER2- BC subtype (p <0.01 and p <0.05, respectively). In triple-negative breast cancer (TNBC), single marker-positive intratumoral TILs did not affect prognosis, however CD4/PDL1, CD8/PD1, and CD8/PDL1 double-positive TILs were significantly associated with TNBC recurrence (p<0.05, p<0.01, and p<0.001, respectively). TIL profiles differed among different BC subtypes, suggesting that the localization of TILs and their tumor-specific subsets influence the BC microenvironment.

Phenotypic, functional, and metabolic heterogeneity of immune cells infiltrating non–small cell lung cancer

Lung cancer is the leading cancer in the world, accounting for 1.2 million of new cases annually, being responsible for 17.8% of all cancer deaths. In particular, non–small cell lung cancer (NSCLC) is involved in approximately 85% of all lung cancers with a high lethality probably due to the asymptomatic evolution, leading patients to be diagnosed when the tumor has already spread to other organs. Despite the introduction of new therapies, which have improved the long-term survival of these patients, this disease is still not well cured and under controlled. Over the past two decades, single-cell technologies allowed to deeply profile both the phenotypic and metabolic aspects of the immune cells infiltrating the TME, thus fostering the identification of predictive biomarkers of prognosis and supporting the development of new therapeutic strategies. In this review, we discuss phenotypic and functional characteristics of the main subsets of tumor-infiltrating lymphocytes (TILs) and tumor-infiltrating myeloid cells (TIMs) that contribute to promote or suppress NSCLC development and progression. We also address two emerging aspects of TIL and TIM biology, i.e., their metabolism, which affects their effector functions, proliferation, and differentiation, and their capacity to interact with cancer stem cells.

Research Progress on the Anticancer Activities and Mechanisms of Polysaccharides From Ganoderma

Cancer ranks as a primary reason for death worldwide. Conventional anticancer therapies can cause severe side effects, and thus natural products may be promising drug candidates for cancer therapy. Accumulating evidence has verified the prominent anticancer properties of Ganoderma polysaccharides, suggesting that Ganoderma polysaccharides may be effective chemopreventive agents of natural origin. Based on their abilities to prevent cancer development by regulating the DNA damage response, cancer cell proliferation, apoptosis, host immunity, gut microbiota and therapeutic sensitivity, there has been increasing interest in elucidating the clinical implication of Ganoderma polysaccharides in cancer therapy. In this review, we summarize recent findings pertaining to the roles of bioactive polysaccharides from Ganoderma in cancer pathogenesis, discuss the multifarious mechanisms involved and propose future directions for research. A more sophisticated understanding of the anticancer benefits of Ganoderma polysaccharides will be helpful for improving current treatments and developing novel therapeutic interventions for human malignancies.

Therapy resistance: opportunities created by adaptive responses to targeted therapies in cancer

Normal cells explore multiple states to survive stresses encountered during development and self-renewal as well as environmental stresses such as starvation, DNA damage, toxins or infection. Cancer cells co-opt normal stress mitigation pathways to survive stresses that accompany tumour initiation, progression, metastasis and immune evasion. Cancer therapies accentuate cancer cell stresses and invoke rapid non-genomic stress mitigation processes that maintain cell viability and thus represent key targetable resistance mechanisms. In this Review, we describe mechanisms by which tumour ecosystems, including cancer cells, immune cells and stroma, adapt to therapeutic stresses and describe three different approaches to exploit stress mitigation processes: (1) interdict stress mitigation to induce cell death; (2) increase stress to induce cellular catastrophe; and (3) exploit emergent vulnerabilities in cancer cells and cells of the tumour microenvironment. We review challenges associated with tumour heterogeneity, prioritizing actionable adaptive responses for optimal therapeutic outcomes, and development of an integrative framework to identify and target vulnerabilities that arise from adaptive responses and engagement of stress mitigation pathways. Finally, we discuss the need to monitor adaptive responses across multiple scales and translation of combination therapies designed to take advantage of adaptive responses and stress mitigation pathways to the clinic.

Targeting of the Peritumoral Adipose Tissue Microenvironment as an Innovative Antitumor Therapeutic Strategy

The tumor microenvironment (TME) plays a key role in promoting and sustaining cancer growth. Adipose tissue (AT), due to its anatomical distribution, is a prevalent component of TME, and contributes to cancer development and progression. Cancer-associated adipocytes (CAAs), reprogrammed by cancer stem cells (CSCs), drive cancer progression by releasing metabolites and inflammatory adipokines. In this review, we highlight the mechanisms underlying the bidirectional crosstalk among CAAs, CSCs, and stromal cells. Moreover, we focus on the recent advances in the therapeutic targeting of adipocyte-released factors as an innovative strategy to counteract cancer progression.

Molecular Docking as a Therapeutic Approach for Targeting Cancer Stem Cell Metabolic Processes

Cancer stem cells (CSCs) are subpopulation of cells which have been demonstrated in a variety of cancer models and involved in cancer initiation, progression, and development. Indeed, CSCs which seem to form a small percentage of tumor cells, display resembling characteristics to natural stem cells such as self-renewal, survival, differentiation, proliferation, and quiescence. Moreover, they have some characteristics that eventually can demonstrate the heterogeneity of cancer cells and tumor progression. On the other hand, another aspect of CSCs that has been recognized as a central concern facing cancer patients is resistance to mainstays of cancer treatment such as chemotherapy and radiation. Owing to these details and the stated stemness capabilities, these immature progenitors of cancerous cells can constantly persist after different therapies and cause tumor regrowth or metastasis. Further, in both normal development and malignancy, cellular metabolism and stemness are intricately linked and CSCs dominant metabolic phenotype changes across tumor entities, patients, and tumor subclones. Hence, CSCs can be determined as one of the factors that correlate to the failure of common therapeutic approaches in cancer treatment. In this context, researchers are searching out new alternative or complementary therapies such as targeted methods to fight against cancer. Molecular docking is one of the computational modeling methods that has a new promise in cancer cell targeting through drug designing and discovering programs. In a simple definition, molecular docking methods are used to determine the metabolic interaction between two molecules and find the best orientation of a ligand to its molecular target with minimal free energy in the formation of a stable complex. As a comprehensive approach, this computational drug design method can be thought more cost-effective and time-saving compare to other conventional methods in cancer treatment. In addition, increasing productivity and quality in pharmaceutical research can be another advantage of this molecular modeling method. Therefore, in recent years, it can be concluded that molecular docking can be considered as one of the novel strategies at the forefront of the cancer battle via targeting cancer stem cell metabolic processes.

Dual Inhibition of Myc Transcription and PI3K Activity Effectively Targets Colorectal Cancer Stem Cells

Simple Summary

Compelling evidence has shown that cancer stem cells (CSCs) are responsible for high resistance to conventional anti-cancer therapies. Here, we demonstrate that the tumor microenvironment protects CR-CSCs from EGFR/HER2, BRAF and PI3K targeting, promoting CD44v6 and Myc expression. Alternatively, as a substitution for HER2 and BRAF, the Myc transcription inhibitor can overcome the protective effects of microenvironmental cytokines, impairing the survival of CR-CSCs. These data highlight the targeting of Myc and PI3K activity as a novel therapeutic strategy against advanced colorectal cancer.

Abstract

Despite advances in the curative approach, the survival rate of advanced colorectal cancer (CRC) patients is still poor, which is likely due to the emergence of cancer cell clones resistant to the available therapeutic options. We have already shown that CD44v6-positive CRC stem cells (CR-CSCs) are refractory toward standard anti-tumor therapeutic agents due to the activation of the PI3K pathway together with high HER2 expression levels. Tumor microenvironmental cytokines confer resistance to CR-CSCs against HER2/PI3K targeting by enhancing activation of the MAPK pathway. Here, we show that the CSC compartment, spared by BRAF inhibitor-based targeted therapy, is associated with increased expression levels of CD44v6 and Myc and retains boosted clonogenic activity along with residual tumorigenic potential. Inhibition of Myc transcription, downstream of the MAPK cascade components, and PI3K pathway activity was able to overcome the protective effects of microenvironmental cytokines, affecting the survival and the clonogenic activity of CR-CSCs, regardless of their mutational background. Likewise, the double targeting induced stabilization of mouse tumor avatars. Altogether, these data outline the rationale for dual kinase targeting of CR-CSCs to prevent their adaptive response, which would lead to disease progression.