Chemoresistance Of Cancer Cells Research Articles

Dysregulation of Cholesterol Homeostasis in Ovarian Cancer.

Cholesterol plays an essential role in maintaining the rigidity of cell membranes and signal transduction. Various investigations confirmed empirically that the dysregulation of cholesterol homeostasis positively correlates with tumor progression. More specifically, recent studies suggested the distinct role of cholesterol in ovarian cancer cell proliferation, metastasis and chemoresistance. In this review, we summarize the current findings that suggest the contribution of cholesterol homeostasis dysregulation to ovarian cancer progression and resistance to anti-cancer agents. We also discuss the therapeutic implications of cholesterol-lowering drugs in ovarian cancer.

The Illustration of Altered Glucose Dependency in Drug-Resistant Cancer Cells.

A chemotherapeutic approach is crucial in malignancy management, which is often challenging due to the development of chemoresistance. Over time, chemo-resistant cancer cells rapidly repopulate and metastasize, increasing the recurrence rate in cancer patients. Targeting these destined cancer cells is more troublesome for clinicians, as they share biology and molecular cross-talks with normal cells. However, the recent insights into the metabolic profiles of chemo-resistant cancer cells surprisingly illustrated the activation of distinct pathways compared with chemo-sensitive or primary cancer cells. These distinct metabolic dynamics are vital and contribute to the shift from chemo-sensitivity to chemo-resistance in cancer. This review will discuss the important metabolic alterations in cancer cells that lead to drug resistance.

Characterization of chemoresistant human non-small cell lung cancer cells by metabolic and lipidomic profiling.

Lung cancer is one of the most malignant cancers and the leading cause of cancer-related deaths worldwide, while acquired chemoresistance would represent a major problem in the treatment of non-small cell lung cancer (NSCLC) because of the reduced treatment effect and increased rates of recurrence. To establish the chemoresistant NSCLC cells, doxorubicin was treated to A549 cells over 3 months at gradually increasing concentrations from 0.03 to 0.5 µM. Real-time PCR and Western blotting were employed for investigating mRNA and protein expression of the glutathione peroxidase (GPX) protein family and multidrug resistance protein 1 (MRP1) in A549 and A549/CR cells. We also employed gas chromatography mass-spectrometry and nano electrospray ionization mass-spectrometry coupled with multivariate statistical analysis to characterize the unique metabolic and lipidomic profiles of chemoresistant NSCLC cells in order to identify potential therapeutic targets. Reactive oxygen species levels were decreased, and mRNA and protein levels of GPX2 and multidrug resistance protein 1 (MRP1) were increased in A549/CR. We identified 87 metabolites and intact lipid species in A549 and A549/CR. Among these metabolites, lactic acid, glutamic acid, glycine, proline, aspartic acid, succinic acid, and ceramide, alongside the PC to PE ratio, and arachidonic acid-containing phospholipids were suggested as characteristic features of chemoresistant NSCLC cells (A549/CR). This study reveals characteristic feature differences between drug-resistance NSCLC cells and their parental cells. We suggest potential therapeutic targets in chemoresistant NSCLC. Our results provide new insight into metabolic and lipidomic alterations in chemoresistant NSCLC. This could be used as fundamental information to develop therapeutic strategies for the treatment of chemoresistant NSCLC patients.

Proteomics Analysis Revealed Smad3 as a Potential Target of the Synergistic Antitumor Activity of Disulfiram and Cisplatin in Ovarian Cancer.

Among gynecological cancers, ovarian cancer has a high mortality rate. Cisplatin-based chemotherapy is commonly used for the treatment of ovarian cancer. However, the clinical efficacy of cisplatin in ovarian cancer is limited due to the development of chemo-resistance during treatment. In the study, we aimed to investigate the synergistic anti-cancer activity and targets of the FDA-approved drug disulfiram combined with cisplatin in ovarian cancer. The cell viability was determined by Celltier-Glo luminescent assay. The synergistic anti-cancer activity was assessed by combination index. Cell cycle and apoptosis were detected by flow cytometry. The in vivo anti-tumor activity and side effects were evaluated using a xenografted mice model. The synergistic anti-cancer targets were identified by a mass spectrometry-based proteomics analysis. In this study, we first found that disulfiram synergistically enhanced the anti-tumor activity of cisplatin in chemo-resistant ovarian cancer cells, which was accompanied by the enhanced induction of cellular apoptosis. Secondly, the in vivo study demonstrated that the combination treatment of disulfiram and cisplatin dramatically inhibited tumor growth and had no apparent side effects in ovarian cancer xenografted mice. Finally, proteomics analysis identified SMAD3 as a potential target of disulfiram-cisplatin combined treatment, and the down-regulation of SMAD3 could increase cisplatin-induced cell death in ovarian cancer. Combination treatment of disulfiram and cisplatin synergistically inhibited the growth of ovarian cancer through down-regulating SMAD3. As a repurposed drug, disulfiram could be quickly transformed into a clinic to overcome cisplatin resistance for the treatment of ovarian cancer.

Physical Dissolution Combined with Photodynamic Depletion: A Two-Pronged Nanoapproach for Deoxygenation-Driven and Hypoxia-Activated Prodrug Therapy.

Hypoxia may enhance the chemoresistance of cancer cells and can significantly compromise the effectiveness of chemotherapy. Many efforts have been made to relieve or reverse hypoxia by introducing more oxygen into the tumor microenvironment (TME). Acting in a diametrically opposite way, in the current study, a novel nanocarrier was designed to further exhaust the oxygen level of the hypoxic TME. By creating such an oxygen depleted TME, the hypoxia-selective cytotoxin can work effectively, and oxygen exhaustion triggered chemotherapy can be achieved. Herein, deoxygenation agent, FDA-approved perfluorocarbon (PFC) and photosensitizer indocyanine green (ICG) for oxygen depletion, along with the hypoxia-activating drug tirapazamine (TPZ), were coincorporated within the poly(lactic-co-glycolic acid) (PLGA) nanoemulsion (ICG/TPZ@PPs) for the treatment of hypoxic tumors. Following hypoxia amplifying through physical oxygen dissolution and photodynamic depletion in tumors, hypoxic chemotherapy could be effectively activated to improve multitreatment synergy. After achieving local tumor enrichment, PFC-mediated oxygen dissolution combined with further ICG-mediated photodynamic therapy (PDT) under near-infrared (NIR) laser irradiation could induce enhanced hypoxia, which would activate the antitumor activity of codelivered TPZ to synergize cytotoxicity. Remarkably, in vivo experimental results exhibited that deoxygenated ICG/TPZ@PPs-based photothermal therapy (PTT), PDT, and hypoxia activated chemotherapy have an excellent synergistic ablation of tumors without obvious side effects, and therefore, a broad prospect of application of this nanocarrier could be expected.

MiR-708–3p promotes gastric cancer progression through downregulating ETNK1

MicroRNAs (miRNAs) are small, evolutionarily conserved, non-coding RNAs playing a role in the proliferation, metastasis, apoptosis, chemo-sensitivity, and chemo-resistance of gastric cancer, as well as the stemness of gastric cancer stem cells. miR-708–3p induces gastric cancer cell chemo-resistance, but its actual role in gastric cancer progression remains unclear. This paper shows that miR-708–3p is upregulated in gastric cancer samples and that a high miR-708–3p expression in gastric cancer patients is associated with poor overall survival. Our functional study results indicate that miR-708–3p overexpression promotes gastric cancer cell proliferation and migration, inhibits cell apoptosis, and facilitates the transition from the G0/G1 to the G2/M phase. Furthermore, reducing miR-708–3p levels yielded opposite effects. Next, our in vivo experiments revealed that miR-708–3p advanced gastric cancer cell growth in nude mice. The underlying mechanism was the regulation of ethanolamine kinase 1 (ETNK1) expression by miR-708–3p, which bound to the 3′UTR of the ETNK1 gene in gastric cancer cells. Finally, the recovery assay results showed that ETNK1 overexpression could slow miR-708-3p-induced gastric cancer progression. In conclusion, we identified a new miR-708–3p/ETNK1 pathway involved in gastric cancer progression. These results may offer new targets for gastric cancer therapy and markers for gastric cancer prognosis.

Preparation and characterization of ionic metal-based anticancer formulations of the type [bis-DACH tolfenamate metal {Co(II), Cu(II) and Zn(II)}] complexes: Binding studies with ct-DNA/tRNA, cleavage and cytotoxic activity against chemoresistant cancer cells

A series of ionic metallo-NSAID’s having the formulae [Co(DACH)2(H2O)2](tolf)21, [Cu(DACH)2(H2O)2](tolf)22 and [Zn(DACH)2(H2O)2](tolf)23 where DACH and tolf− are 1,2-diaminocyclohexane and tolfenamate anion, respectively were synthesized. Complexes 1–3 were characterized by FT–IR, EPR, 1H/13C NMR, UV–vis and ESI–MS spectrometry methods. The bonding features as well as the electronic structure of all the complexes were optimized using DFT studies. Binding affinity of parent NSAID and 1–3 complexes with ct–DNA/tRNA were studied by using various complementary biophysical methods. The corroborative results of these experimental studies revealed that they were capable to interact with the therapeutic targets, ct–DNA/tRNA by the electrostatic interactions, showing higher preference for tRNA as compared to ct–DNA as quantified by their binding strength (Kb and Ksv values). It was also observed that the complexes exhibited much higher binding affinity than the parent free NSAID. A concentration-dependent cleavage of the complexes was observed with tRNA which promoted the hydrolysis of RNA. The cytotoxicity of 1–3 was evaluated against chemo-resistant phenotypes of cancers, viz., breast cancer cell line (MCF- 7), cervical cancer cell line (SiHa), triple-negative breast cancer cell (MDA-MB-231), oral squamous cancer cell (AW13516) and lung cancer cell line (Hop-62) by SRB assay. The cytotoxicity activity results displayed that among all the ionic tolfenamate metal complexes, complex 2 showed a much superior cytotoxic profile against treated cancer cell lines (SiHa, MDA-MB-231, AW13516, MCF-7 and Hop-62) with a good GI50 value of (4.7 ± 0.03) µg/ml, (10.5 ± 0.36) µg/ml, (19.2 ± 0.02) µg/ml, (4.1 ± 0.05) µg/ml, and (18.2 ± 0.04) µg/ml, respectively, while the complexes 1 and 3 showed moderate activity. Cell morphology studies were carried out in AW13516, MDA–MB–231, MCF–7 and Hop–62 cells with the incubation of complexes for a period of 48 h which implicated that the cells exposed to complex 2 presented round features and were nonadherent in culture. These morphological changes indicated that complex 2 was capable of inducing cell death, probably by apoptosis suggesting copper complex 2 was promising potent anticancer agent.

The promoting effects of GPR176 expression on proliferation, chemoresistance, lipogenesis and invasion of oesophageal cancer

PurposeAs a member of the G-protein-coupled receptor 1 family, the G-protein-coupled receptor 176 (GPR176) gene encodes a glycosylated protein made up of 515 amino acids. The current study was performed to evaluate the impact of GPR176 on the clinicopathology and prognosis of oesophageal cancer, as well as uncover its molecular mechanisms.MethodsBioinformatics and clinical tissue samples were used to detect the expression and clinicopathological significance of GPR176 in oesophageal cancer. The expression, proliferation, migration and invasion, apoptosis and lipid droplet formation of GPR176 gene in oesophageal cancer were performed as phenotypic readouts.ResultsHere, RT-PCR and bioinformatic analyses revealed that GPR176 mRNA expression was significantly higher in oesophageal cancer than in normal mucosa (p < 0.05). GPR176 mRNA expression was associated with low weight and BMI, low T stage, low N and clinicopathological stage, low histological grade and favourable clinical outcome of oesophageal cancer (p < 0.05). The differential genes of GPR176 mRNA were involved in protein digestion and absorption, extracellular matrix constituent, endoplasmic reticulum lumen, among others (p < 0.05). GPR176-related genes were classified as being involved in oxidoreductase activity, actin and myosin complexes, lipid localisation and transport, among others (p < 0.05). GPR176 knockdown suppressed proliferation, anti-apoptotic and anti-pyroptotic properties, migration, invasion, chemoresistance and lipid droplet formation in oesophageal cancer cells (p < 0.05), while ACC1 and ACLY overexpression reversed the inhibitory effects of GPR176 silencing on lipid droplet formation and chemoresistance.ConclusionThese findings indicated that upregulated expression of GPR176 might be involved in oesophageal carcinogenesis and subsequent progression, aggressiveness, and induced chemoresistance by ACC1- and ACLY-mediated lipogenesis and lipid droplet assembly.

Potansiyel JNK1 İnhibe Edici Aktiviteye Sahip 2-((4-(dimetilamino)benziliden)amino)-5-metilfenol’ün Sentezi, Teorik Çalışmaları, Sitotoksisitesi

Cisplatin, doxorubicin, hydroxycamptothecin, leucovorin, vincristine and 5-fluorouracil resistance of cancer cells are associated with the activities of C-Jun N-Terminal Kinase 1 (JNK1). Inhibition of the JNK1 by pharmacological agents could be a beneficial attempt for reversing the chemoresistance of various cancer cells. However, there is no FDA-approved JNK inhibitor for safe use in clinics in today’s clinics. In this study, a Schiff base 2-((4-(dimethylamino)benzylidene)amino)-5-methylphenol, (7S4) has been synthesized and characterized by 1H, 13C-NMR, FT-IR and elemental analysis. The stable geometry of 7S4 has been determined by DFT method with Gaussian09 program (B3LYP/6-311g++(d,p))). The Gibbs Free energies, stable tautomer forms, H-bond, Mulliken charges, dipole moment, natural bond orbital (NBO), HOMO, LUMO and band gap energy (EGAP), molecular electrostatic potential (MEP) and solvent accessibility surface areas (SASA) have been calculated. Drug-likeness, anticancer and JNK1 inhibitory activities of 7S4 have been evaluated. Enol tautomer form of trans 7S4 was characterized as the most stable structure. 7S4 was observed to be a reactive compound in chemical reactions with a low EGAP value. In addition, high and low electron density regions of 7S4 are responsible for the establishment of chemical bonds in biological systems. 7S4 exhibited strong druggability with the agreement on Lipinski, Ghose, Veber, Egan, and Muegge rules. Cytotoxicity tests and molecular docking revealed that 7S4 poses a potential JNK1 inhibitor activity.

Anti-cancer effectiveness of a novel ceramide analog on chemo-sensitive and chemo-resistant breast cancers.

Ceramides are known to show anti-cancer activity. A novel ceramide analog, (S,E)-3-hydroxy-2-(2-hydroxybenzylidene)amino-N-tetradecylpropanamide (analog 315) was developed as part of a larger study focused on finding more effective breast cancer treatments. To assess whether analog 315 shows any or a combination of the following effects in breast cancer cells in vitro: inhibiting proliferation, inducing apoptosis, and altering protein expression. Also, to determine whether it inhibits chemo-resistant breast cancer tumor growth in vivo mouse model. In vitro cell proliferation and apoptosis after treatment with analog 315 were assessed in three breast cancer cell lines (MCF-7, MCF-7TN-R, and MDA-MB-231) and reported. Protein expression was assessed by microarray assay. For the in vivo studies, chemo-resistant breast cancer cells were used for tumor development in two groups of mice (treated and control). Analog 315 (25 mg/kg/day) or control (dimethyl sulfoxide) was administered intraperitoneally for 7 days. Effects of analog 315 on inhibiting the growth of chemo-resistant breast cancer tumors after treatment are reported. Analog 315 reduced MCF-7TN-R chemo-resistant tumor burden (volume and weight) in mice. Liver metastasis was observed in control mice, but not in the treated animals. Ki-67, a proliferation marker for breast cancer cells, increased significantly ( P < 0.05) in control tumor tissue. In vitro studies showed that analog 315 inhibited cell proliferation, altered protein expression and induced apoptosis in all three breast cancer cell lines studied, of which the effects on MCF-7TN-R cells were the most significant. Analog 315 reduced tumor growth in chemo-resistant breast cancer, inhibited cell proliferation, altered protein expression, and induced apoptosis in all three cell lines studied.

A New Quinone-Based Inhibitor of Mitochondrial Complex I in D-Conformation, Producing Invasion Reduction and Sensitization to Venetoclax in Breast Cancer Cells.

Mitochondrial Complex I plays a crucial role in the proliferation, chemoresistance, and metastasis of breast cancer (BC) cells. This highlights it as an attractive target for anti-cancer drugs. Using submitochondrial particles, we identified FRV-1, an ortho-carbonyl quinone, which inhibits NADH:duroquinone activity in D-active conformation and reduces the 3ADP state respiration dependent on Complex I, causing mitochondrial depolarization, ATP drop, increased superoxide levels, and metabolic remodeling towards glycolysis in BC cells. Introducing methyl groups at FRV-1 structure produced analogs that acted as electron acceptors at the Complex I level or increased the inhibitory effect of FCCP-stimulated oxygen consumption rate, which correlated with their redox potential, but increased toxicity on RMF-621 human breast fibroblasts was observed. FRV-1 was inactive in the naphthoquinone oxidoreductase 1 (NOQ1)-positive BC cell line, MCF7, but the sensitivity was recovered by dicoumarol, a NOQ1 inhibitor, suggesting that FRV-1 is a NOQ1 substrate. Importantly, FRV-1 selectively inhibited the proliferation, migration, and invasion of NQO1 negative BC cell, MDA-MB-231, in an OXPHOS- and ROS-dependent manner and sensitized it to the BH3 mimetic drug venetoclax. Overall, FRV-1 is a novel Complex I inhibitor in D-active conformation, blocking possibly the re-activation to A-state, producing selective anti-cancer effects in NQO1-negative BC cell lines.

3-deazaneplanocin A, a histone methyltransferase inhibitor, improved the chemoresistance induced under hypoxia in melanoma cells

One of common characteristics of solid tumors is low O2 level, so-called hypoxia, which plays a critical role in chemoresistance. Epigenetic mechanism such as DNA methylation and histone modification is involved in cancer development and progression. There is ample evidence that epigenetic drugs reversed acquired chemoresistance in cancer cells under normal O2 level, normoxia. However, it remains unknown whether epigenetic drugs improve acquired chemoresistance under hypoxia. The aim of our study was to investigate whether epigenetic drugs can improve the chemoresistance induced under hypoxia in cancer cells. In murine melanoma B16-BL6 (B16) cells, the culture under hypoxia, 1%O2 caused the elevated expression of hypoxia-inducible factor-1α (HIF-1α) and its target genes. The chemoresistance to 7-ethyl-10-hydroxycamptothecin (SN-38, the active metabolite of irinotecan) was also acquired under hypoxia in B16 cells. In addition, as epigenetic mechanisms, the protein expression of the enhancer of zeste homolog 2 (EZH2), histone methyltransferase and its target histone H3 trimethylation at lysine 27 (H3K27Me3) level increased under hypoxia. The induction of H3K27Me3 under hypoxia was suppressed by EZH2 siRNA and 3-deazaneplanocin A (DZNep), an EZH2 inhibitor. Furthermore, both EZH2 siRNA and DZNep significantly reduced the cell viability after SN-38 treatment and improved the chemoresistance to SN-38 under hypoxia. These results indicated that the chemoresistance to SN-38 under hypoxia would arise from epigenetic mechanism, H3K27Me3 elevation due to EZH2 induction. In conclusion, a histone methyltransferase EZH2 inhibitor, DZNep was capable of tackling acquired chemoresistance via the suppression of histone methylation induced under hypoxic tumor microenvironment.

CD39+MDSC facilitates cisplatin resistance of ovarian cancer cells by affecting adenosine synthesis.

Chemoresistance is a major cause of relapse or death in ovarian cancer (OC) patients. New evidence suggests the crucial role of myeloid-derived suppressor cells (MDSCs) in mediating chemoresistance of cancer cells. We aimed to dissect the way MDSCs affect the cisplatin resistance phenotype of OC and the related mechanisms. MDSCs were isolated from the spleen of OC mice isograft. CCK-8 and colony formation assays revealed the effects of an MDSC-conditioned medium with dysregulated CD39 on the proliferation and cisplatin sensitivity of OC cells. Fluorescence assay was used to reveal the effects of MDSCs with dysregulated CD39 on adenosine triphosphate (ATP) hydrolysis and adenosine (ADO) synthesis. MDSCs with highly expressed CD39 could facilitate the proliferation and cisplatin resistance of OC cells, while MDSCs with downregulated CD39 caused the opposite results. In addition, MDSCs with upregulated CD39 could facilitate the hydrolysis of immunogenic ATP to immunosuppressive ADO, while the introduction of CD39 inhibitor could repress such hydrolysis of ATP and generation of ADO, thereby abating the proliferation and cisplatin resistance of OC cells. CD39+MDSC could promote the proliferation and cisplatin resistance of OC cells by generating high concentrations of ADO, which indicates that targeting CD39+MDSC might be a feasible way to improve cisplatin resistance in OC.

A spotlight on the interplay between Wnt/β-catenin signaling and circular RNAs in hepatocellular carcinoma progression.

Hepatocellular carcinoma (HCC) is one of the deadliest cancers due to multifocal development and distant metastasis resulting from late diagnosis. Consequently, new approaches to HCC diagnosis and treatment are required to reduce mortality rates. A large body of evidence suggests that non-coding RNAs (ncRNAs) are important in cancer initiation and progression. Cancer cells release many of these ncRNAs into the blood or urine, enabling their use as a diagnostic tool. Circular RNAs (CircRNAs) are as a members of the ncRNAs that regulate cancer cell expansion, migration, metastasis, and chemoresistance through different mechanisms such as the Wnt/β-catenin Signaling pathway. The Wnt/β-catenin pathway plays prominent roles in several biological processes including organogenesis, stem cell regeneration, and cell survival. Aberrant signaling of both pathways mentioned above could affect the progression and metastasis of many cancers, including HCC. Based on several studies investigated in the current review, circRNAs have an effect on HCC formation and progression by sponging miRNAs and RNA-binding proteins (RBPs) and regulating the Wnt/β-catenin signaling pathway. Therefore, circRNAs/miRNAs or RBPs/Wnt/β-catenin signaling pathway could be considered promising prognostic and therapeutic targets in HCC.

Advances in regulation and function of stearoyl-CoA desaturase 1 in cancer, from bench to bed.

Stearoyl-CoA desaturase 1 (SCD1) converts saturated fatty acids to monounsaturated fatty acids. The expression of SCD1 is increased in many cancers, and the altered expression contributes to the proliferation, invasion, sternness and chemoresistance of cancer cells. Recently, more evidence has been reported to further support the important role of SCD1 in cancer, and the regulation mechanism of SCD1 has also been focused. Multiple factors are involved in the regulation of SCD1, including metabolism, diet, tumor microenvironment, transcription factors, non-coding RNAs, and epigenetics modification. Moreover, SCD1 is found to be involved in regulating ferroptosis resistance. Based on these findings, SCD1 has been considered as a potential target for cancer treatment. However, the resistance of SCD1 inhibition may occur in certain tumors due to tumor heterogeneity and metabolic plasticity. This review summarizes recent advances in the regulation and function of SCD1 in tumors and discusses the potential clinical application of targeting SCD1 for cancer treatment.

Tissue Inhibitor of Metalloproteinases-1 Overexpression Mediates Chemoresistance in Triple-Negative Breast Cancer Cells.

Triple-negative breast cancer (TNBC) is among the most aggressive breast cancer subtypes. Despite being initially responsive to chemotherapy, patients develop drug-resistant and metastatic tumors. Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a secreted protein with a tumor suppressor function due to its anti-proteolytic activity. Nevertheless, evidence indicates that TIMP-1 binds to the CD63 receptor and activates noncanonical oncogenic signaling in several cancers, but its role in mediating TNBC chemoresistance is still largely unexplored. Here, we show that mesenchymal-like TNBC cells express TIMP-1, whose levels are further increased in cells generated to be resistant to cisplatin (Cis-Pt-R) and doxorubicin (Dox-R). Moreover, public dataset analyses indicate that high TIMP-1 levels are associated with a worse prognosis in TNBC subjected to chemotherapy. Knock-down of TIMP-1 in both Cis-Pt-R and Dox-R cells reverses their resistance by inhibiting AKT activation. Consistently, TNBC cells exposed to recombinant TIMP-1 or TIMP-1-enriched media from chemoresistant cells, acquire resistance to both cisplatin and doxorubicin. Importantly, released TIMP-1 reassociates with plasma membrane by binding to CD63 and, in the absence of CD63 expression, TIMP-1-mediated chemoresistance is blocked. Thus, our results identify TIMP-1 as a new biomarker of TNBC chemoresistance and lay the groundwork for evaluating whether blockade of TIMP-1 signal is a viable treatment strategy.

CAF-derived exosomal lncRNA FAL1 promotes chemoresistance to oxaliplatin by regulating autophagy in colorectal cancer

Oxaliplatin is a widely applied anti-cancer drug in clinics for colorectal cancer (CRC) treatment. Nonetheless, the treatment efficacy is always limited by the acquisition of chemoresistance in cancer cells. The deregulation of long non-coding RNA (lncRNA) FAL1 has been implicated in the tumorigenesis and progression of different malignancies. Nevertheless, the possible contribution of lnc-FAL1 in drug resistance development of CRC has not been investigated. Here, we reported the overexpression of lnc-FAL1 in CRC samples, and elevated lnc-FAL1 levels seemed to be associated with the poor survival in CRC patients. We further demonstrated that lnc-FAL1 promoted oxaliplatin chemoresistance in both cell and animal model. Additionally, lnc-FAL1 was mainly derived from exosomes secreted by cancer associated fibroblasts (CAFs), and lnc-FAL1-containing exosomes or lnc-FAL1 overexpression significantly inhibited oxaliplatin-induced autophagy in CRC cells. Mechanistically, lnc-FAL1 acted as a scaffold for the interaction between Beclin1 and TRIM3 to promote TRIM3-dependent Beclin1 polyubiquitination and degradation, thereby suppressing oxaliplatin-induced autophagic cell death. In summary, these data imply a molecular mechanism through which CAF-derived exosomal lnc-FAL1 contributes to the acquisition of oxaliplatin resistance in CRC.

Plant-derived extracts P2Et and Anamu-SC affect NO and ROS levels in leukemic cells

Leukemic cells often show high nitric oxide (NO) and reactive oxygen species (ROS) levels. These can lead to resistance to apoptosis and therapy and increased proliferation. Plant-derived extracts decrease chemoresistance in cancer cells. In this study, we evaluated the effects of the plant-derived extracts P2Et (Caesalpinia spinosa) and Anamu-SC (Petiveria alliacea) and their combination with chemotherapeutic agents on NO and ROS levels in leukemic cell lines K562 and Reh. NO and ROS were determined using the DAF-FM DA and H2DCFDA probes. The mean fluorescence intensity for each variable was measured by flow cytometry. The extracts showed an antioxidant effect on both cell lines leading to a significant decrease in ROS levels without decreasing cell viability. Anamu-SC also increased NO levels in K562 cells when combined with idarubicin. Both extracts reduced the number of leukemic cells after 12 hours of treatment. Further studies are necessary to evaluate their effect on primary human leukemia cells. These findings suggest the potential of P2Et and Anamu-SC as adjuncts in leukemia treatment.

Anastasis enhances metastasis and chemoresistance of colorectal cancer cells through upregulating cIAP2/NFκB signaling

Chemotherapy is a common strategy to treat cancer. However, acquired resistance and metastasis are the major obstacles to successful treatment. Anastasis is a process by which cells survive executioner caspase activation when facing apoptotic stress. Here we demonstrate that colorectal cancer cells can undergo anastasis after transient exposure to chemotherapeutic drugs. Using a lineage tracing system to label and isolate cells that have experienced executioner caspase activation in response to drug treatment, we show that anastasis grants colorectal cancer cells enhanced migration, metastasis, and chemoresistance. Mechanistically, treatment with chemotherapeutic drugs induces upregulated expression of cIAP2 and activation of NFκB, which are required for cells to survive executioner caspase activation. The elevated cIAP2/NFκB signaling persists in anastatic cancer cells to promote migration and chemoresistance. Our study unveils that cIAP2/NFκB-dependent anastasis promotes acquired resistance and metastasis after chemotherapy.

The PRMT5 inhibitor C9 mitigates hypoxia-induced carboplatin resistance in lung cancer by inducing autophagy.

Hypoxia, a common feature of solid tumors, can promote chemoresistance in cancer cells. PRMT5 mediates various cellular processes involved in cancer development and progression. However, the role of PRMT5 in hypoxia-induced chemoresistance is unclear. In this study, hypoxia upregulated PRMT5 expression in lung cancer cells. Additionally, PRMT5 overexpression promoted cancer cell resistance to carboplatin. In carboplatin-resistant cancer cells, PRMT5 overexpression promoted the methylation of ULK1, a critical regulator of autophagy. ULK1 hypermethylation leads to the upregulation of autophagy, which can improve the survival of cancer cells under hypoxic conditions. Furthermore, this study demonstrated that the PRMT5 inhibitor C9 significantly enhanced the sensitivity of lung cancer cells to carboplatin. These findings suggest that targeting PRMT5-mediated autophagy with C9 can overcome hypoxia-induced carboplatin resistance and improve the efficacy of chemotherapy in patients with cancer.