REVIEW | doi:10.20944/preprints201710.0021.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ncRNAs; ovarian cancer; chemoresistance
Online: 4 October 2017 (11:59:09 CEST)
With the advancement of next generation sequencing in past several years, a rising number of non-coding RNAs have been found as new actors to regulate gene expression. Non-coding RNAs not only play important roles in carcinogenesis, but also affect the clinical treatment strategies. They have been proved to be deeply correlated with chemoresistance in several cancers. Ovarian cancer is the leading cause of death in gynecological malignancy, with low 5-year survival rate. Most patients are identified when they have late-stage disease. This review mainly makes a compilation of the most relevant research literature in this field with the purpose of shedding light on the relation between ncRNAs and chemoresistance in ovarian cancer.
REVIEW | doi:10.20944/preprints202002.0015.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: cholangiocarcinoma; autophagy inhibition; autophagy inhibition; chemoresistance
Online: 3 February 2020 (05:20:36 CET)
Autophagy is a multistep catabolic process through which misfolded, aggregated or mutated proteins and damaged organelles are internalized in membrane vesicles called autophagosomes and ultimately fused to lysosomes for degradation of sequestered components. The multi-step nature of the process offers multiple regulation points prone to be deregulated and cause different human disease, but also offers multiple targetable points for designing therapeutic strategies. Cancer cells have evolved to use autophagy as an adaptive mechanism to survive under extremely stressful conditions within tumor microenvironment, but also to increase invasiveness and resistance to anti-cancer drugs such as chemotherapy. This review collects all clinical evidences of autophagy deregulation during cholangiocarcinogenesis together with all pre-clinical reports evaluating compounds that modulate autophagy to induce cholangiocarcinoma (CCA) cell death. Altogether, experimental data suggests an impairment of autophagy during initial steps of CCA development and increased expression of autophagy markers on established tumors and in invasive phenotypes. Pre-clinical efficacy of autophagy modulators promoting CCA cell death, reducing invasiveness capacity and resensitizing CCA cells to chemotherapy open novel therapeutic avenues to design more specific and efficient strategies to treat this aggressive cancer
REVIEW | doi:10.20944/preprints202302.0122.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: Osteosarcoma; Tumorigenesis; Metastasis; Immune Evasion; Chemoresistance; Mutation
Online: 7 February 2023 (06:12:43 CET)
There has been no significant efficacy in treatment for osteosarcoma (OS) metastasis after nearly four decades of trials. This motivates us to elucidate OS therapies according to their four bidirectional mutation stages. To refresh the OS therapy status quo, the historical developments and clinical advancements are briefly described. However, the main issue of metastasis remains unresolved, accounting for 90% of pulmonary metastasis deaths. Thus, this metastasis problem is related to immune evasion and chemoresistance that are being induced after long-term treatment by the use of immunotherapy for tumorigenesis. Therefore, it is rationale to discuss the relationship cycles of mutation stages including tumorigenesis, metastasis, immune evasion, and chemoresistance. Even though many combinational and targeted therapies have been developed to intensify these mutation treatments, successful clinical translations with higher cure rates are still rare. Through this review, an in-depth understanding of the bidirectional relationship between the four OS mutation stages and their respective therapies is provided. Herein, we summarise the medicines used to treat tumorigenesis, including COLGALT2 inhibitors, Tra2B, and AGAP1, miR-148a and miR-21-5p EVs, and the lncRNA LIFR-AS1. Following the medicines used to treat metastasis are AXL, miR-135a-5p, mRNA BCL6, TGFβ1, Tim-3, SOCS5, CASC15, KLF3-AS1, PDCD4, ATG5, and Rab22a-NeoF1. Then the medicines used to treat immune evasion are N-cadherin, anti-IL-9, USP12 inhibitor, IgG-4+ B-cells, LAP inhibitor, anti-Wnt2 mAb, anti-αvβ8 integrin, HK2-mediated IκBα, IDO inhibitor with NO, and TGF-βRII with anti-IgG1. Finally, the medicines used to treat chemoresistance are DHFR, FPGS, HSP-90AA1, XCT-790, ATKI, and IGF1. As a result, this contribution is expected to serve as a reference and guide for scientists and clinicians.
REVIEW | doi:10.20944/preprints201709.0162.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: omega-3; PUFA; chemoresistance; membrane; DHA; EPA
Online: 29 September 2017 (18:32:40 CEST)
The efficacy of chemotherapy depends on sensitivity and intrinsic or acquired drug resistance of cancer cells. The n-3 long chain polyunsaturated fatty acids (n-3 LCPUFAs) are considered chemosensitizing agents and revertants of multidrug resistance by pleiotropic mechanisms. The specific mechanisms are not fully understood, but nowadays, it is widely accepted that there are a complex network of mechanisms, including alteration in gene expression, modulation of cellular proliferation and differentiation, induction of apoptosis, generation of reactive oxygen species and lipid peroxidation. A crucial mechanism in the control of cell drug uptake and efflux is related to n-3 LCPUFA influence on membrane lipid composition. The incorporation of docosahexaenoic acid in the lipid rafts produces significant changes in their physical-chemical properties affecting content and functions of transmembrane proteins, such as growth factors, receptors and ATP-binding cassette transporters. Of note, n-3 LCPUFAs often impact on the lipid compositions more in chemoresistant cells than in chemosensitive cells, suggesting their adjuvant role in cancer treatment.
ARTICLE | doi:10.20944/preprints202305.0197.v1
Subject: Medicine And Pharmacology, Obstetrics And Gynaecology Keywords: cell lines; chemoresistance; EpCAM; extracellular vesicles; HGSOC 1
Online: 4 May 2023 (05:18:59 CEST)
Platinum-resistant high-grade serous ovarian cancer (HGSOC) is invariably a fatal disease, so a central goal in ovarian cancer research is to develop novel strategies to overcome platinum resistance. Treatment is thus moving towards personalized therapy. However, validated molecular biomarkers to predict patients’ risk of developing platinum resistance are still lacking. Extracellular vesicles (EVs) are promising candidates for biomarkers. EpCAM-specific EVs are largely unexplored biomarkers in predicting chemoresistance. Using transmission electron microscopy, nanoparticle tracking analysis and flow cytometry, we compared the characteristics of EVs released from a cell line derived from a clinically confirmed cisplatin-resistant patient (OAW28) and EVs released from two cell lines from tumors sensitive to platinum-based chemotherapy (PEO1, OAW42). We showed that characteristics of EVs released from the HGSOC cell line of chemoresistant patients had higher heterogeneity in size, a larger proportion of medium/large (>200nm) EVs and a higher number of released EpCAM-positive EVs of different sizes, although expression of EpCAM predominated, especially on those larger than 400 nm. We also determined a strong positive correlation between the concentration of EpCAM-positive EVs and expression of cellular EpCAM. These results may contribute to prediction of platinum resistance in the future, although they should first be validated in clinical samples.
REVIEW | doi:10.20944/preprints201806.0262.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: ovarian cancer; cancer stem cells; signaling, chemoresistance, metastasis
Online: 15 June 2018 (15:14:22 CEST)
Ovarian cancer is the most lethal gynecological malignancy. Poor overall survival, particularly for patients with high grade serous (HGS) ovarian cancer, are often attributed to late stage at diagnosis and relapse following chemotherapy. HGS ovarian cancer is a heterogenous disease in that few genes are consistently mutated between patients. Additionally, HGS ovarian cancer is characterized by high genomic instability. For these reasons personalized approaches may be necessary for effective treatment and cure. Understanding the molecular mechanisms that contribute to tumor metastasis and chemoresistance are essential to improve survival rates. One favored model for tumor metastasis and chemoresistance is the cancer stem cell (CSC) model. CSCs are cells with enhanced self-renewal properties that are enriched following chemotherapy. Elimination of this cell population is thought to be a mechanism to increase therapeutic response. Therefore, accurate identification of stem cell populations that are most clinically relevant is necessary. While many CSC identifiers (ALDH, OCT4, CD133, and side population) have been established, it is still not clear which population(s) will be most beneficial to targeted in patients. Therefore, there is a critical need to characterize CSCs with reliable markers and find their weaknesses that will make the CSCs amenable to therapy. Many signaling pathways are implicated for their roles in CSC initiation and maintenance. Therapeutically targeting pathways needed for CSC initiation or maintenance may be an effective way of treating HGS ovarian cancer patients. In conclusion, the prognosis for HGS ovarian cancer may be improved by combining CSC phenotyping with targeted therapies for pathways involved in CSC maintenance.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: Non–Small Cell Lung Cancer; cisplatin; chemoresistance; molecular mechanisms
Online: 14 July 2021 (11:25:13 CEST)
Cancer cells utilize a number of mechanisms to increase their survival and progression as well as their resistance to anticancer therapy: deregulation of growth regulatory pathways by acquiring grow factor independence, immune system suppression, reducing the expression of antigens activating T lymphocyte cells (mimicry), induction of anti-apoptotic signals to counter the action of drugs, activation of several DNA repair mechanisms and driving the active efflux of drugs from the cell cytoplasm and epigenetic regulation by microRNAs (miRNAs). Due to the fact that it is commonly diagnosed late, lung cancer remains a major malignancy with a low five-year survival rate; when diagnosed, the cancer is often highly advanced and the cancer cells may have acquired drug resistance. This review summarizes the main mechanisms involved in cisplatin resistance and in interactions between cisplatin-resistant cancer cells and the tumor microenvironment. It also analyses changes in the gene expression profile of cisplatin sensitive vs. cisplatin resistant non–small cell lung cancer (NSCLC) cellular model using the GSE108214 Gene Expression Omnibus database. It describes a protein-protein interaction network that indicates highly-dysregulated TP53, MDM2 and CDKN1A genes as they encodes the top networking proteins that may be involved in cisplatin tolerance, these all being upregulated in cisplatin-resistant cells. Furthermore, it illustrates the multifactorial nature of cisplatin resistance by examining the diversity of dysregulated pathways present in cisplatin-resistant NSCLC cells based on KEGG pathway analysis.
ARTICLE | doi:10.20944/preprints201907.0152.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: molecular iodine; breast cancer; chemoresistance; immune response; transcriptomic analysis
Online: 11 July 2019 (05:49:35 CEST)
This study analyzes oral supplement of molecular iodine (I2) alone and in combination with the neoadjuvant therapy 5-fluorouracil/epirubicin/cyclophosphamide or taxotere/epirubicin (FEC/TE) in women with Early (stage II) and Advanced (stage III) breast cancer. In the Early group, 30 women were treated with I2 (5 mg/day) or placebo (colored water) for 7–35 days before surgery. For the Advanced group, 30 patients received I2 or placebo along with FEC/TE treatment. After surgery, all patients received FEC/TE + I2 for 170 days. I2 supplementation showed a significant attenuation of the side effects and absence of tumor chemoresistance. Control, I2, FEC/TE, and FEC/TE+I2 groups exhibit response rate of 0, 33%, 73%, and 100%, respectively, and a pathologic complete response of 18%, and 36% in the last two groups. Five-year disease-free survival rate was significantly higher in patients with I2 supplement before and after surgery compared to those receiving the supplement only after surgery (82% vs. 46%). I2-treated tumors exhibit less invasive potential, and significant increases in apoptosis, estrogen receptor expression, and immune cell infiltration. Transcriptomic analysis indicated activation of the antitumoral immune response. The results led us to register a phase III clinical trial analyzing chemotherapy + I2 treatment for advanced breast cancer.
ARTICLE | doi:10.20944/preprints202309.1245.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Hypoxia; CML; Bcr/Abl; chemoresistance; Imatinib; Crizotinib; 2-methoxyestradiol (2ME2)
Online: 20 September 2023 (07:48:05 CEST)
Chronic myeloid leukemia (CML) is the most common form of leukemia in adults and accounts for approximately 15% of all leukemia cases. The etiology of this disease is based on the presence of the oncogenic Bcr/Abl fusion protein, which has dysregulated tyrosine kinase activity. This pathological condition is the result of a chromosomal translocation between chromosomes 9 and 22 leading to the formation of the Philadelphia chromosome (Ph). Clinical establishment of targeted therapy with Abl kinase inhibitors (AKIs) has been observed in the treatment of CML. Therapy resistance in patients with CML is due to genetic alterations in the cells of CML, specifically affecting the Bcr/Abl oncoprotein. Acquired resistance of CML patients to tyrosine kinase inhibitors (AKIs) has also been associated with the tumor microenvironment (TME). This study aimed to examine the role of hypoxic conditions in the development of chemoresistance to certain AKIs in CML. The findings of our study indicate that exposure to hypoxic conditions leads to a substantial increase in chemoresistance to crizotinib, while only resulting in a slight increase in chemoresistance to imatinib. It is worth noting that both drugs effectively block Bcr/Abl function. Furthermore, it was observed that the inclusion of the JAK1/2 inhibitor ruxolitinib resulted in an augmentation of chemoresistance to crizotinib in the context of hypoxia. Overexpression of hypoxia-inducible factor 1a (HIF1a) and silencing of JAK2 confirmed that the two proteins cooperate in mediating chemoresistance to crizotinib in CML cell lines. It is noteworthy that the compound 2-methoxy estradiol (2ME2), which is a metabolite of estradiol lacking estrogenic activity, has shown efficacy in reinstating the sensitivity of CML cells to crizotinib in the presence of hypoxic circumstances. Additionally, when used in conjunction with a JAK2 inhibitor, 2ME2 exhibited activity in restoring crizotinib sensitivity in CML cells. The findings of our study underscore the significance of selectively targeting elements of the HIF1α pathway in order to achieve total eradication of chronic myeloid leukemia (CML) cells.
ARTICLE | doi:10.20944/preprints202309.1256.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: hypoxia; CML; Bcr/Abl; chemoresistance; imatinib; crizotinib; 2-methoxyestradiol (2ME2)
Online: 19 September 2023 (07:23:27 CEST)
Chronic myeloid leukemia (CML) is the most common form of leukemia in adults and accounts for approximately 15% of all leukemia cases. The etiology of this disease is based on the presence of the oncogenic Bcr/Abl fusion protein, which has dysregulated tyrosine kinase activity. This pathological condition is the result of a chromosomal translocation between chromosomes 9 and 22 leading to the formation of the Philadelphia chromosome (Ph). Clinical establishment of targeted therapy with Abl kinase inhibitors (AKIs) has been observed in the treatment of CML. Therapy resistance in patients with CML is due to genetic alterations in the cells of CML, specifically affecting the Bcr/Abl oncoprotein. Acquired resistance of CML patients to tyrosine kinase inhibitors (AKIs) has also been associated with the tumor microenvironment (TME). This study aimed to examine the role of hypoxic conditions in the development of chemoresistance to certain AKIs in CML. The findings of our study indicate that exposure to hypoxic conditions leads to a substantial increase in chemoresistance to crizotinib, while only resulting in a slight increase in chemoresistance to imatinib. It is worth noting that both drugs effectively block Bcr/Abl function. Furthermore, it was observed that the inclusion of the JAK1/2 inhibitor ruxolitinib resulted in an augmentation of chemoresistance to crizotinib in the context of hypoxia. Overexpression of hypoxia-inducible factor 1 (HIF1) and silencing of JAK2 confirmed that the two proteins cooperate in mediating chemoresistance to crizotinib in CML cell lines. It is noteworthy that the compound 2-methoxy estradiol (2ME2), which is a metabolite of estradiol lacking estrogenic activity, has shown efficacy in reinstating the sensitivity of CML cells to crizotinib in the presence of hypoxic circumstances. Additionally, when used in conjunction with a JAK2 inhibitor, 2ME2 exhibited activity in restoring crizotinib sensitivity in CML cells. The findings of our study underscore the significance of selectively targeting elements of the HIF1α pathway in order to achieve total eradication of chronic myeloid leukemia (CML) cells.
REVIEW | doi:10.20944/preprints202302.0510.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Metal-Based Drugs; CuZn; Anti-Chemoresistance; Osteosarcoma Therapy; Ligand Biosensors.
Online: 28 February 2023 (06:51:00 CET)
Due to its built-up chemoresistance after prolonged usage, the demand for replacing platinum in metal-based drugs (MBD) is rising. The first MBD approved by the FDA for cancer therapy was cisplatin in 1978. Even after nearly four and a half decades of trials, there has been no significant improvement in osteosarcoma (OS) therapy. In fact, many MBD have been developed, but the chemoresistance problem raised by platinum remains unresolved. This motivates us to elucidate the possibilities of the copper and zinc (CuZn) combination to replace platinum in MBD. Thus, the anti-chemoresistance properties of CuZn and their physiological functions for OS therapy are highlighted. Herein, we summarise their chelators, main organic solvents, and ligand functions in their structures that are involved in anti-chemoresistance properties. Through this review, it is rational to discuss their ligands’ roles as biosensors in drug delivery systems. Hereafter, an in-depth understanding of their redox and photoactive function relationships is provided. The disadvantage is that the other functions of biosensors cannot be elaborated on here. As a result, this review is being developed, which is expected to intensify OS drugs with higher cure rates. Nonetheless, this advancement intends to solve the major chemoresistance obstacle towards clinical efficacy.
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Kinase Inhibitor; NEK2; Chemoresistance; Avicennia marina; Marine compounds; Molecular docking; Cancer
Online: 7 June 2020 (11:16:35 CEST)
Never in mitosis gene A-related kinase 2 (NEK2) a member of serine-threonine kinase protein mainly involved in the cell cycle process. Clinical studies revealed NEK2 overexpression in various tumour types, also NEK2 was reported for their association with genetic abnormalities like mitotic machinery deregulation and chromosomal instability. Besides NEK2 plays a key role in maintaining the transformed phenotype of cancer cells and chemo-resistance of several tumour types. Thus, NEK2 transcriptional profile is important for diagnosis, treatment, and prognosis stages of cancer studies. Screening of novel NEK2 inhibitor would be beneficial in developing the specific lead molecules. Our studies involved NEK2 transcriptional profile search, screening of druggable cavities in NEK2, Drug likeliness of mangrove derived naphthoquinone derivatives avicennoneA , avicennoneB , avicennoneC , avicennoneD , avicenoneE , avicennone F , and avicennone G , avicequinone A, stenocarpoquinone B , avicequinone C , avicenol A , avicenol C,brugine, apigenin, chrysin and molecular docking studies to assess MNC compounds binding efficacy towards NEK2. Mangrove derived compounds conferred the intermolecular hydrogen bond, Pi-alkyl,pi-cation interactions with NEK2 kinase domain region residues Tyr 19, Lys 37, Arg 164, Lys174. Nearly 200 kinase proteins contained this promising Cys 22 residue as its positioned in the catalytic site like NEK family proteins. Avicenna A, Avicennone G, Chrysin and Brugine formed the irreversible covalent binding with NEK2 through Cys 22, thus they can be considered as potential kinase inhibitors with the limited off-target response. But these MNC compounds need to be tested further in invitro and invivo studies to propose as potent NEK2 inhibitors.
ARTICLE | doi:10.20944/preprints201807.0223.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: 4-AAQB; SOD2; hsa-miR-324; colon cancer stem cells; chemoresistance; chemosensitivity
Online: 13 July 2018 (04:24:11 CEST)
Background: Colorectal cancer (CRC) remains a leading cause of cancer-related morbidity and mortality in both sexes globally. This is not unconnected with the heterogeneity and plasticity of CRC stem cells (CRC-SCs) which stealthily exploit niche-related and (epi)genetic factors to facilitate metastasis, chemoresistance, tumor recurrence, and disease progression. Despite accumulating evidence of the role of dysregulated microRNAs in malignancies, the therapeutic efficacy of pharmacological-targeting of CRC-SC-associated microRNAs is relatively under-explored. Experimental approach: In this present study, we employed relatively new bioinformatics approaches, analyses of microarray data, western blot, RT-PCR, and functional assays to show that hsa-miR-324-5p expression is significantly suppressed in CRC cells, and inversely correlates with the aberrant expression of SOD2. Results: This converse hsa-miR-324-5p/SOD2 relationship is associated with enhanced oncogenicity, which is effectively inhibited by 4-AAQB as evidenced by inhibited cell viability and proliferation, as well as, attenuated migration, invasion and clonogenicity in 4-AAQB-treated DLD1 and HCT116 cells. We also showed that 4-AAQB-induced re-expression of hsa-miR-324-5p, akin to short-interfering RNA reduced SOD2 expression, correlates with the concurrent down-regulation of SOD2, N-cadherin, vimentin, c-Myc, and BcL-xL2, with concomitant up-regulation of E-cadherin and BAX2 proteins. Enhanced expression of hsa-miR-324-5p in the CRC cells suppressed their tumorigenicity in vitro and in vivo. Additionally, 4-AAQB synergistically potentiates FOLFOX anticancer effect by eliciting the re-expression of SOD2-suppressed hsa-miR-324 and inhibiting SOD2-mediated tumorigenicity. Conclusion: Our findings highlight the pre-clinical anti-CSC efficacy of 4-AAQB, with or without FOLFOX in CRC, and suggest a potential novel therapeutic strategy for CRC patients.
BRIEF REPORT | doi:10.20944/preprints202207.0144.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Protein Kinase C; PKCeta; autophagy; senescence; chemoresistance; oxidative stress; ER stress; 3MA; chloroquine
Online: 10 July 2022 (06:42:23 CEST)
The emergence of chemoresistance in neoplastic cells is one of the major obstacles in cancer therapy. Autophagy was recently reported as one of the mechanisms that promote chemoresistance in cancer cells by protecting from apoptosis and driving senescence. Thus, understanding the role of autophagy and its underlying signaling pathways is crucial for the development of new therapeutic strategies to overcome chemoresistance. We have previously reported that PKCη is a stress-induced kinase that confers resistance in breast cancer cells against chemotherapy by inducing senescence. Here we show that PKCη promotes autophagy induced by ER and oxidative stress and facilitates the transition from autophagy to senescence. We demonstrate that PKCη knockdown reduces both the autophagic flux and markers of senescence. Additionally, using autophagy inhibitors, such as chloroquine and 3-methyladenine, we show that PKCη and autophagy are required for establishing senescence in MCF-7 in response to oxidative stress. Different drugs used in the clinic are known to induce autophagy and senescence in breast cancer cells. Our study proposes PKCη as a target for therapeutic intervention, acting in synergy with autophagy-inducing drugs, to overcome resistance and enhance cell death in breast cancer.
ARTICLE | doi:10.20944/preprints202205.0201.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: cancer stem cells; colorectal cancer; label-free cell sorting; chemoresistance; intratumoral cellular heterogeneity
Online: 16 May 2022 (09:11:01 CEST)
Cancer stem cells play a crucial role in tumor initiation, metastasis and therapy resistance. Cellular heterogeneity and plasticity challenge the isolation of cancer stem cells. The impact of intratumoral cellular heterogeneity in the context of treatment resistance using a label-free approach remains understudied. Here, we use the sedimentation field-flow fractionation technique to separate, without labeling, cell subpopulations of colorectal cancer cell lines and primary cultures according to their biophysical properties. One of the three cell subpopulations sorted by SdFFF exhibits cancer stem cell traits, including high tumorigenicity in vivo, and a higher frequency of tumor-initiating cells compared to the other subpopulations. In vitro two- and three-dimensional chemosensitivity assays emphasize the therapeutic relevance of this cancer stem cell-like subpopulation due to its chemoresistance. Therefore, our findings highlight a label-free cell sorting approach to reveal intratumoral cellular heterogeneity and its implication in therapy resistance. This approach enables the study of the individualized response of each sorted cell subpopulation by breaking down the tumor, thus offering new perspectives for personalized therapy.
REVIEW | doi:10.20944/preprints202005.0315.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cancer stem cells; tumor microenvironment; metastasis; chemoresistance; epithelial to mesenchymal transition; clinical trials
Online: 19 May 2020 (14:01:27 CEST)
Despite great strides being achieved in improving cancer patients’ outcomes through better therapies and combinatorial treatment, several hurdles still remain due to therapy resistance, cancer recurrence and metastasis. Drug resistance, culminating in relapse and metastatic disease continue to be associated with fatal disease. Cancer stem cells (CSCs) are a subpopulation of cancer cells known to be resistant to therapy and cause metastasis. Whilst the debate on whether CSCs are the origins of the primary tumor rages on, CSCs have been further characterised in many cancers with data illustrating that CSCs display great abilities to self-renew, withstand therapies due to enhanced epithelial to mesenchymal (EMT) properties, enhanced expression of ABC membrane transporters, activation of several survival signaling pathways and increased immune evasion DNA repair mechanisms. CSCs also display great heterogeneity with the consequential lack of specific CSC markers presenting a great challenge to their targeting. In this updated review we re-visit CSCs within the tumor microenvironment (TME) and present novel treatment strategies targeting CSCs. These promising strategies include targeting CSCs-specific properties using small molecule inhibitors, immunotherapy, microRNA mediated inhibitors, epigenetic methods as well as targeting CSC niche-microenvironmental factors and differentiation. Lastly, we present recent clinical trials undertaken to try to turn the tide against cancer by targeting CSC-associated drug resistance and metastasis.
ARTICLE | doi:10.20944/preprints202302.0103.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Hepatocellular carcinoma (HCC); HepG2; Transglutaminase 2 (TG2); Cisplatin; Chemoresistance; Sub-cellular localisation; Apoptosis; Autophagy
Online: 6 February 2023 (10:56:44 CET)
Hepatocellular carcinoma (HCC) is a heterogeneous malignancy with complex carcinogenesis. Although there has been significant progress in the treatment of HCC over the past decades, drug resistance to chemotherapy remains a major obstacle in its successful management. In this study we were able to reduce chemoresistance in cisplatin-resistant HepG2 cells by either silencing the expression of transglutaminase type 2 (TG2) using siRNA or by pre-treatment of cells with the TG2 enzyme inhibitor cystamine. Further analysis revealed that, whereas the full-length TG2 isoform (TG2-L) was almost completely cytoplasmic in its distribution, the majority of the short TG2 isoform (TG2-S) was membrane-associated in both parental and chemoresistant HepG2 cells. Following induction of cisplatin toxicity in non-chemoresistant parental cells, TG2-S together with cisplatin quickly relocated to the cytosolic fraction. Conversely, no cytosolic relocalisation of TG2-S or nuclear accumulation cisplatin was observed following identical treatment of chemoresistant cells, where TG2-S remained predominantly membrane-associated. This suggests that deficient subcellular relocalisation of TG2-S from membranous structures into the cytoplasm may limit the apoptic response to cisplatin toxicity in chemoresistant cells. Structural analysis of TG2 revealed the presence of binding motifs for interaction of TG-S with the membrane scaffold protein LC3/LC3 homologue that could contribute to a novel mechanism of chemotherapeutic resistance in HepG2 cells.
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: microRNA; epithelial-mesenchymal transition; 5-fluorouracil; oxaliplati; FOLFOX; chemoresistance; pharmacogenetics; pharmacoepigenetics; EMT-transcription factors; biomarker.
Online: 13 November 2020 (10:47:43 CET)
The FOLFOX scheme, based on the association of 5-fluorouracil and oxaliplatin, is the most frequently indicated chemotherapy scheme for patients diagnosed with metastatic colorectal cancer. Nevertheless, development of chemoresistance is one of the major challenges associated with this disease. It has been reported that epithelial-mesenchymal transition (EMT) is implicated in microRNA-driven modulation of tumor cells response to 5-fluorouracil and oxaliplatin. Besides, from pharmacogenomic research it is known that overexpression of genes encoding dihydropyrimidine dehydrogenase (DPYD), thymidylate synthase (TYMS), methylenetetrahydrofolate reductase (MTHFR), the DNA repair enzymes ERCC1, ERCC2, and XRCC1, and the phase 2 enzyme GSTP1 impair the response to FOLFOX. It has been observed that EMT is associated with overexpression of DPYD, TYMS, ERCC1, and GSTP1. In this review we investigated the role of miRNAs as EMT promotors in tumor cells, and its potential effect on upregulation of DPYD, TYMS, MTHFR, ERCC1, ERCC2, XRCC1 and GSTP1 expression, which would lead to resistance of CRC tumor cells to 5-fluorouracil and oxaliplatin. This constitutes a potential mechanism of epigenetic regulation involved in late-onset of acquired resistance in mCRC patients under FOLFOX chemotherapy. Expression of these biomarkers microRNA could serve as tools for personalized medicine, and as potential therapeutic targets in the future.
REVIEW | doi:10.20944/preprints201809.0434.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: colorectal cancer, cancer stem cells, mesenchymal stromal cells, stem cell markers, chemoresistance, treatment personalization, biomarkers, cancer stem cell markers
Online: 21 September 2018 (10:07:54 CEST)
BACKGROUND: Treatment failure in primary as well as metastatic cancer patients, caused by chemo and radio resistance, has truncated the research for the applicability of personalized medicine. The use of stem cells and cancer stem cells in such a treatment approach will be reviewed in this study. RESULTS: CRC stem cells prove to be a promising asset for CRC treatment optimization both by serving as biomarkers for the current therapy modalities by means of treatment personalization and patient/tumor stratification, as well as in the development of targeted therapies, selective for the stem cell population. Similar conclusions are drawn, regarding mesenchymal stromal cells and their effect in CRC therapy; while resident stromal cells of tumor microenvironment seem to promote the tumorigenic and metastatic processes in addition to conferring to the chemo- and radio resistance, under certain conditions they are able to improve the treatment outcome of CRC chemotherapy, e.g. by targeted enzyme/prodrug treatment of CRC cells. CONCLUSION: This review, truncates the dynamic potential of cancer stem cells and other stem cell types in CRC treatment personalization as well as, in the improvement of current treatment approaches opting to a higher therapeutic rate, improved prognosis, survival and quality of life for CRC patients.
REVIEW | doi:10.20944/preprints202211.0271.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: cisplatin; carboplatin; oxaliplatin; cellular uptake; DNA damage; transcription regulation; non-nuclear targets; chemoresistance; mechanisms of action; clinical usages; influx and efflux pumps; ribosome biogenesis; ER stress response; immunogenic cell death; interstrand and intrastrand DNA cross-links.
Online: 15 November 2022 (03:38:06 CET)
Cisplatin (CDDP), carboplatin (CP), and oxaliplatin (OXP) are three platinating agents clinically approved worldwide for use against a variety of cancers. They are canonically known as DNA damage inducers; however, that is only one of their mechanisms of cytotoxicity. CDDP mediates its effects through DNA damage-induced transcription inhibition and apoptotic signalling. In addition, CDDP targets the endoplasmic reticulum (ER) to induce ER-stress, the mitochondria via mitochondrial DNA damage leading to ROS production, and the plasma membrane and cytoskeletal components. CP acts in a similar fashion to CDDP by inducing DNA damage, mitochondrial damage, and ER stress. Additionally, CP is also able to upregulate micro-RNA activity, enhancing intrinsic apoptosis. OXP, on the other hand, at first induces damage to all the same targets as CDDP and CP, yet it is also capable of inducing immunogenic cell death via ER stress and can decrease ribosome biogenesis through its nucleolar effects. In this comprehensive review, we provide detailed mechanisms of action for the three platinating agents, going beyond their nuclear effects to include their cytoplasmic impact within cancer cells. In addition, we cover their current clinical use and limitations, including side effects and mechanisms of resistance.