Resistant Cells Research Articles

Cancer-associated fibroblast-derived COL17A1 promotes gemcitabine resistance and tumorigenesis in pancreatic cancer cells by interacting with ACTN4.

Cancer-associated fibroblasts (CAFs) are key components of tumor microenvironment and have been identified to be involved in modulating drug resistance in cancers by secreting molecules. Pancreatic cancer (PC) is a leading cause of cancer mortality with high aggressiveness. Gemcitabine (GEM) is one of primary antineoplastic drugs for PC. Collagen XVII (COL17A1) expression was found to be upregulated in GEM-resistant CAFs. Here, this study focused on investigating whether CAFs affected GEM resistance in PC by secreting COL17A1 and its associated mechanisms. In total, 60 newly diagnosed PC patients only with GEM-based chemotherapy were recruited. Normal fibroblasts (NFs) and CAFs were isolated using fresh normal and resistant PC tissues. Human pancreatic duct epithelial (HPDE) cells were used for functional analyses. Levels of COL17A1 and Actinin Alpha 4 (ACTN4) were measured by using qRT-PCR and western blotting. Functional analyses were conducted using MTT, 5-ethynyl-2'-deoxyuridine, transwell, and sphere formation assays, respectively. The interaction between COL17A1 and ACTN4 was analyzed by Co-immunoprecipitation and immunofluorescence assays. Animal models were established for in vivo analysis. CAF incubation promoted GEM resistance and enhanced the proliferation, invasion and stemness in GEM-resistant PC cells. COL17A1 was highly expressed in resistant CAFs and GEM-resistant PC cells, and CAF incubation could increase COL17A1 expression in resistant PC cells. Moreover, COL17A1 silencing in GEM-resistant PC cells or the incubation of COL17A1-decreased CAF with GEM-resistant PC cells could suppress GEM resistance and cell oncogenic phenotype progression. Mechanistically, COL17A1 interacted with ACTN4 protein, and the anticancer effects mediated by COL17A1-decreased CAFs in resistant PC cells were reversed by ACTN4 overexpression. In vivo assay also showed that COL17A1-decreased CAFs suppressed the growth and GEM resistance in PC by ACTN4. CAFs-derived COL17A1 promoted GEM resistance and tumorigenesis in PC by interacting with ACTN4, suggesting a new method for overcoming GEM resistance in PC.

Exploring BCL2 regulation and upstream signaling transduction in venetoclax resistance in multiple myeloma: potential avenues for therapeutic intervention

Investigating venetoclax (VTX) resistance in multiple myeloma (MM) is crucial for the development of novel therapeutic strategies to tackle resistance. We conducted a multi-omic characterization of established VTX-resistant isogenic human myeloma cell lines (HMCL) and primary MM patient samples pre- and post-VTX treatment. Transcriptomic and proteomic analysis revealed that resistance was largely associated with BCL-2 family protein dysregulation, including upregulation of anti-apoptotic proteins such as MCL-1, BCL-XL, BCL-2, and downregulation of pro-apoptotic members. Notably, the re-introduction of BIM into resistant cells restored VTX sensitivity and synergized with MCL-1 inhibitors. Upstream signaling pathways, including growth factor receptor tyrosine kinase (RTK) and phosphoinositide-3-kinase (PI3K) were implicated in this dysregulation. Simultaneous inhibition of MCL-1, BCL-XL, and upstream PI3K, RTK (FGF, EGF, and IGF1) mediated signaling enhanced VTX sensitivity. Post-translational modifications of MCL-1, particularly its stabilization via acetylation and phosphorylation, were investigated, although their inhibition only marginally increased VTX sensitivity. Lastly, the inhibition of AURKA and mitochondrial respiration also improved VTX sensitivity in some resistant HMCLs. Our findings suggest that combining VTX with MCL-1 and BCL-XL inhibitors or PIK3/RTK inhibitors holds potential for overcoming resistance. The study illustrates the importance of understanding molecular determinants of resistance to develop tailored therapeutic strategies.

Tumor-associated macrophage-derived exosome miR-194 confers cisplatin resistance in GC cells

ObjectiveAt all stages of gastric cancer (GC), cisplatin is the first-line chemotherapeutic agent, but its efficacy remains limited, with a response rate of less than 20%, largely because of resistance to the drug. It aims to determine whether macrophage-derived exosomes are involved in the mechanism of cisplatin resistance, in order to identify potential methods for reversing resistance and improving patient outcomes.MethodsMacrophages induced by IL-13 and IL-4 were characterized using flow cytometry, then co-cultured with GC cells and cisplatin. Cell viability and apoptosis were subsequently evaluated through CCK-8 assays and flow cytometry. Exosome miR-194, derived from M2 macrophages, was characterized and co-cultured with gastric cancer cells and cisplatin to assess cell survival. Furthermore, a mouse GC model was established, and miR-194 was injected to observe tumor growth.ResultsResults indicate that M2 macrophages enhance cisplatin resistance in gastric cancer cells mainly through miR-194, as demonstrated by CCK-8 and apoptosis assays. Cellular uptake experiments demonstrated that miR-194 can transfer from macrophages to GC cells and exert functional effects. Western blotting and PCR analysis further confirmed that macrophage-derived miR-194 inhibits apoptosis in GC cells and enhances cisplatin resistance by downregulating PTEN.ConclusionMacrophage-derived miR-194 promotes cisplatin resistance in GC cells by inhibiting apoptosis through PTEN downregulation. These findings provide new insights and theoretical backing for clinical treatment strategies in GC.

Identification and validation of TSPAN13 as a novel temozolomide resistance-related gene prognostic biomarker in glioblastoma.

Glioblastoma (GBM) is the most lethal primary tumor of the central nervous system, with its resistance to treatment posing significant challenges. This study aims to develop a comprehensive prognostic model to identify biomarkers associated with temozolomide (TMZ) resistance. We employed a multifaceted approach, combining differential expression and univariate Cox regression analyses to screen for TMZ resistance-related differentially expressed genes (TMZR-RDEGs) in GBM. Using LASSO Cox analysis, we selected 12 TMZR-RDEGs to construct a risk score model, which was evaluated for performance through survival analysis, time-dependent ROC, and stratified analyses. Functional enrichment and mutation analyses were conducted to explore the underlying mechanisms of the risk score and its relationship with immune cell infiltration levels in GBM. The prognostic risk score model, based on the 12 TMZR-RDEGs, demonstrated high efficacy in predicting GBM patient outcomes and emerged as an independent predictive factor. Additionally, we focused on the molecule TSPAN13, whose role in GBM is not well understood. We assessed cell proliferation, migration, and invasion capabilities through in vitro assays (including CCK-8, Edu, wound healing, and transwell assays) and quantitatively analyzed TSPAN13 expression levels in clinical glioma samples using tissue microarray immunohistochemistry. The impact of TSPAN13 on TMZ resistance in GBM cells was validated through in vitro experiments and a mouse orthotopic xenograft model. Notably, TSPAN13 was upregulated in GBM and correlated with poorer patient prognosis. Knockdown of TSPAN13 inhibited GBM cell proliferation, migration, and invasion, and enhanced sensitivity to TMZ treatment. This study provides a valuable prognostic tool for GBM and identifies TSPAN13 as a critical target for therapeutic intervention.

LB-100 Enhances Drugs Efficacy Through Inhibition of P-Glycoprotein Expression in Multidrug-Resistant Glioblastoma and Non-Small Cell Lung Carcinoma Cellular Models

Background/Objectives: This study explores the potential of LB-100 (a protein phosphatase 2A—PP2A inhibitor) combined with adavosertib (a WEE1 kinase inhibitor) and doxorubicin (DOX), to overcome multidrug resistance (MDR) in cancer cells and enhance treatment efficacy. Methods: We evaluated LB-100 combinations with adavosertib and DOX in patient-derived glioblastoma and non-small cell lung carcinoma cells (NSCLCs) using a real-time cell analyzer. Effectiveness was also assessed through immunofluorescence assay, and interactions were analyzed via SynergyFinder+. We also examined P-glycoprotein (P-gp) expression and drug resistance genes’ expression in MDR glioblastoma and NSCLCs after LB-100 treatment, as well as LB-100 sensitizing effect on DOX and DOX accumulation. Results: LB-100 significantly boosts the effectiveness of adavosertib and DOX after multiple applications. It also enhances these drugs’ cytotoxicity in a single application without acting synergistically. Additionally, LB-100 reduces P-gp expression in MDR glioblastoma and NSCLCs, sensitizing them to DOX and increasing its accumulation. Conclusions: LB-100 enhances the effectiveness of drugs against MDR cancer cells, presenting a promising strategy to overcome drug resistance in glioblastoma and NSCLCs through P-gp modulation.

Sustained induction of autophagy enhances survival during prolonged starvation in newt cells.

Salamanders demonstrate exceptional resistance to starvation, allowing them to endure extended periods without food in their natural habitats. Although autophagy, a process involving evolutionarily conserved proteins, promotes survival during food scarcity, the specific mechanism by which it contributes to the extreme starvation resistance in newt cells remains unexplored. Our study, using the newt species Pleurodeles waltl, reveals that newt primary fibroblasts maintain constant autophagy activation during prolonged cellular starvation. Unlike normal mammalian fibroblasts, where autophagosome formation increases during acute starvation but returns to baseline levels after extended periods, newt cells maintain elevated autophagosome numbers even 4 d after autophagy initiation, surpassing levels observed in nutrient-rich conditions. Unique P. waltl mTOR orthologs show reduced lysosomal localization compared with mammalian cells in both nutrient-rich and starved states. However, newt cells exhibit dephosphorylation of mTOR substrates under starvation conditions, similar to mammalian cells. These observations suggest that newts may have evolved a distinctive system to balance seemingly conflicting factors: high regenerative capacity and autophagy-mediated survival during starvation.

Carnitine palmitoyltransferase 1C promotes EMT-associated cisplatin resistance in non-small cell lung cancer cells.

Lung cancer is the most common cause of cancer-related deaths worldwide. Platinum-based chemotherapy is one of the main treatment options for patients with non-small cell lung cancer (NSCLC) but the effectiveness of chemotherapy is encumbered by drug resistance. Therefore, understanding the molecular mechanisms underlying chemotherapy resistance is crucial in improving treatment outcomes and prognosis. The cell viability assay and apoptosis were used to analyze chemoresistance. Western blot analysis and wound healing testing were used to evaluate the epithelial-to-mesenchymal transition (EMT). Immunoprecipitation was used for analysis of protein modification. Promoter activity was determined using the luciferase reporter assay. Immunofluorescence staining was used to determine reactive oxygen species levels. The expression patterns of EMT markers and carnitine palmitoyltransferase 1C (CPT1C) were determined by Western blot analysis. CPT1C, which was shown to be highly expressed in lung cancer, is associated with cisplatin resistance in NSCLC cells. CPT1C depletion increased NSCLC cell sensitivity to cisplatin, while overexpression of CPT1C increased NSCLC cell resistance to cisplatin. Induction of EMT mediated CPT1C-induced cisplatin resistance. Ectopic expression of Snail reversed the increase in cisplatin sensitivity triggered by CPT1C knockdown. Moreover, CPT1C was shown to be regulated at the post-translational level and an E3-ubiquitin ligase, NEDD4L, was shown to be a major regulator of CPT1C stability and activity. These data provide evidence for the first time that the lipid metabolism enzyme, CPT1C, mediates resistance to chemotherapy. Therefore, the use of combination therapy with a CPT1C inhibitor may be a promising new avenue in lung cancer treatment.

E2F1 activates breast stromal fibroblasts and promotes their paracrine pro-carcinogenic effects

Breast cancers (BC) are complex neo-organs composed of neoplastic as well as non-carcinogenic cells, in addition to a dynamic extracellular matrix. Active cancer-associated fibroblasts (CAFs) play major roles in the development and spread of breast cancers, through paracrine signaling, which are under the control of several transcription regulators. In the present study, we investigated the role of the transcription factor E2F1 in the active status of CAFs. We have shown that CAFs express higher levels of E2F1 compared to their adjacent tumor counterpart fibroblasts (TCFs). Importantly, E2F1 upregulation by ectopic expression transactivated quiescent breast stromal fibroblasts and promoted their paracrine pro-carcinogenic effects. Indeed, E2F1-expressing fibroblasts were more efficient than their corresponding controls in enhancing the epithelial-to-mesenchymal transition and stemness processes in breast cancer cells both in vitro and in vivo. However, E2F1 knock-down normalized breast CAFs and suppressed their paracrine pro-carcinogenic effects. Interestingly, while fibroblasts expressing high level of E2F1 enhanced the resistance of BC cells to chemotherapeutic drugs, E2F1-deficient fibroblasts enhanced their sensitivity to cisplatin. Together, these findings indicate that the transciption factor E2F1 plays a critical role in the transactivation of breast stromal fibroblasts, and therefore could be a great therapeutic target for precision therapeutics of BC patients.

AXL-Mediated Drug Resistance in ALK-Rearranged NSCLC Enhanced by GAS6 From Macrophages and MMP11 Positive Fibroblasts.

Anaplastic lymphoma kinase (ALK) rearranged non-small cell lung cancer (NSCLC) shows marked tumor shrinkage by ALK-tyrosine kinase inhibitors (TKIs). However, tumors almost inevitably relapse owing to the development of acquired resistance. Resistance mechanisms include secondary ALK mutations and the activation of bypass pathways, such as cMET, cKIT, or EGFR, though some remain unknown. In this study, we analyzed alectinib-resistant patient samples and identified a significant increase in AXL expression in the tumor, and a high level of GAS6, the ligand for AXL, in the pleural effusion. AXL-overexpressing H3122 ALK-rearranged NSCLC cells exhibited partial resistance to alectinib, which was enhanced by GAS6 supplementation but could be overcome by the ALK/AXL inhibitor gilteritinib. Moreover, GAS6-overexpressing NIH3T3 cells and AXL-expressing H3122 cells were subcutaneously injected into the left and right sides of nude mice simultaneously, followed by alectinib treatment. The supply of GAS6 from NIH3T3 may have accelerated tumor relapse under alectinib treatment. However, even without GAS6-overexpressing NIH3T3, AXL-overexpressing H3122 tumor relapsed within 1 month possibly due to increased host mouse Gas6 expression. Single-cell RNA sequencing revealed that specific cancer-associated fibroblasts (CAFs) and a subset of tumor-associated macrophages (TAMs) are the primary sources of Gas6 in the tumor microenvironment (TME). During alectinib treatment, TAMs increased their infiltration into the TME, whereas CAFs altered their expression patterns, substantially upregulating Mmp11. These findings suggest that AXL expression in resistant cancer cells, combined with increased Gas6 production in the TME, contributes to enhanced ALK-TKI resistance.

Targeting ceramide transfer protein sensitizes AML to FLT3 inhibitors via a GRP78-ATF6-CHOP axis.

Sphingolipid, ceramide for example, plays an essential role in regulating cancer cell death. Defects in the generation and metabolism of ceramide in cancer cells contribute to tumor cell survival and resistance to chemotherapy. Ceramide Transfer Protein (CERT) determines the ratio of ceramide and sphingomyelin in cells. Targeting CERT sensitizes solid cancer cells to chemotherapy. However, whether targeting CERT to induce ceramide accumulation thereby improving AML therapy efficiency remains elusive. Here, we show that knocking down CERT inhibits the growth and promotes the apoptosis of AML cells carrying FLT3-ITD mutation. Combining CERT inhibitor with FLT3 inhibitor exhibits synergistic effects on FLT3-ITD mutated acute myeloid leukemia (AML) cells. Additionally, co-treatment of HPA-12 and Crenolanib is effective in FLT3-ITD+ and FLT3-TKD+ AML patients. The synergistic effects are found to be mediated by the endoplasmic reticulum stress-GRP78/ATF6/CHOP axis and mitophagy. Our data provide an effective strategy to enhance the efficacy of FLT3 inhibitors in AML.

Impact of Olive Oil Components on the Expression of Genes Related to Type 2 Diabetes Mellitus

Type 2 diabetes mellitus (T2DM) is a multifactorial metabolic disorder characterized by insulin resistance and beta cell dysfunction, resulting in hyperglycemia. Olive oil, a cornerstone of the Mediterranean diet, has attracted considerable attention due to its potential health benefits, including reducing the risk of developing T2DM. This literature review aims to critically examine and synthesize existing research regarding the impact of olive oil on the expression of genes relevant to T2DM. This paper also seeks to provide an immunological and genetic perspective on the signaling pathways of the main components of extra virgin olive oil. Key bioactive components of olive oil, such as oleic acid and phenolic compounds, were identified as modulators of insulin signaling. These compounds enhanced the insulin signaling pathway, improved lipid metabolism, and reduced oxidative stress by decreasing reactive oxygen species (ROS) production. Additionally, they were shown to alleviate inflammation by inhibiting the NF-κB pathway and downregulating pro-inflammatory cytokines and enzymes. Furthermore, these bioactive compounds were observed to mitigate endoplasmic reticulum (ER) stress by downregulating stress markers, thereby protecting beta cells from apoptosis and preserving their function. In summary, olive oil, particularly its bioactive constituents, has been demonstrated to enhance insulin sensitivity, protect beta cell function, and reduce inflammation and oxidative stress by modulating key genes involved in these processes. These findings underscore olive oil’s therapeutic potential in managing T2DM. However, further research, including well-designed human clinical trials, is required to fully elucidate the role of olive oil in personalized nutrition strategies for the prevention and treatment of T2DM.

A novel acquired resistance mechanism to 5-aminolevulinic acid-mediated photodynamic therapy with ABCG2 inhibition.

We report the occurrence of acquired tumor cell resistance to 5-aminolevulinic acid (ALA)-mediated photodynamic therapy (PDT) in combination with ABCG2 inhibition. ALA-PDT in combination with either an ABCG2 tool inhibitor Ko143 or a repurposed clinically-relevant ABCG2 inhibitor lapatinib was highly effective in eradicating the H4 human glioma cells, resulting in minimal cell survival after treatment. However, after seven rounds of repeated treatments with light dose escalation, the resultant tumor cells became resistant to the combination therapy. The resistant sublines and the parental cell line showed similar ABCG2 activities and protein levels, indicating that it was not ABCG2 that caused the resistance. They also exhibited similar responses to PpIX-PDT and mTOR inhibitor AZD2014, suggesting that alterations in PDT sensitivity and mTOR pathway had little contribution to the development of resistance phenotype. By determining the intracellular and extracellular PpIX levels, the activities and protein levels of heme biosynthesis enzymes, we found that porphobilinogen deaminase (PBGD) activity and protein level were significantly reduced in the resistant sublines, causing resistance to PDT by substantially reducing PpIX biosynthesis. A novel acquired resistance mechanism to ALA-PDT with ABCG2 inhibition has been uncovered.

Leveraging AI to automate detection and quantification of extrachromosomal DNA to decode drug responses

IntroductionTraditional drug discovery efforts primarily target rapid, reversible protein-mediated adaptations to counteract cancer cell resistance. However, cancer cells also utilize DNA-based strategies, often perceived as slow, irreversible changes like point mutations or drug-resistant clone selection. Extrachromosomal DNA (ecDNA), in contrast, represents a rapid, reversible, and predictable DNA alteration critical for cancer’s adaptive response.MethodsIn this study, we developed a novel post-processing pipeline for automated detection and quantification of ecDNA in metaphase Fluorescence in situ Hybridization (FISH) images, leveraging the Microscopy Image Analyzer (MIA) tool. This pipeline is tailored to monitor ecDNA dynamics during drug treatment.ResultsOur approach effectively quantified ecDNA changes, providing a robust framework for analyzing the adaptive responses of cancer cells under therapeutic pressure.DiscussionThe pipeline not only serves as a valuable resource for automating ecDNA detection in metaphase FISH images but also highlights the role of ecDNA in facilitating swift and reversible adaptation to epigenetic remodeling agents such as JQ1.

Disulfiram impairs USP21-mediated MOF-K257 deubiquitination to inhibit esophageal squamous cell carcinoma progression.

Disulfiram (DSF), primarily applied in the therapy for alcohol addiction, has been demonstrated to possess the promising capability of anti-tumor in many human cancers, including esophageal squamous cell carcinoma (ESCC). To date, almost all studies about DSF in ESCC are focusing on investigating either drug combinations or nanoparticle-based delivery systems. However, the exact molecular mechanisms mediating the response to DSF in ESCC are totally unknown. An increasing number of studies reported that aberrant expression of acetylation-related genes is closely involved in regulating the response of cancer cells to anti-tumor drugs. Here, we defined DSF-sensitive and -resistant cells by measuring the half-maximal inhibitory concentration (IC50) of DSF in four ESCC cell lines, followed by detecting the protein expression of nine dysregulated histone acetyltransferase (HAT) genes in ESCC. Our results demonstrate that MOF is responsible for the sensitivity to DSF in ESCC cells. Consistently, DSF treatment markedly abolishes MOF-driving ESCC progression and Wnt/β-Catenin signaling activation. Interestingly, DSF decreased MOF protein expression via the ubiquitin-proteasome system. Further exploration verified the essential role of USP21, among three candidates (USP2, USP21, and USP10), in DSF-mediated MOF protein level. Mechanistically, USP21 binds to MOF protein and decreases the ubiquitination of its K257 site, while DSF notably impedes MOF-mediated ESCC malignant progression and Wnt/β-Catenin signaling activation by blocking USP21-governed MOF-K257 deubiquitination. In conclusion, our study elucidates the USP21/MOF-K257 axis regulating the response to DSF in ESCC, which provides novel and key evidence for the clinical application of DSF in individualized therapy for ESCC patients.

Novel antileukemic compound with sub-micromolar potency against STAT5 addicted myeloid leukemia cells.

Signal Transdcer and Activator of Transcription 5A and 5B (STAT5A/5B) are key effectors of tyrosine kinase oncogenes in myeloid leukemias. It is now clearly evidenced that inhibition of STAT5A/5B not only blocks the growth and survival of myeloid leukemia cells but also overcomes the resistance of leukemic cells to chemotherapy. Previous screening experiments allowed us to identify 17f as a lead compound with promising antileukemic activity that blocks the phosphorylation and transcriptional activity of STAT5A/5B in myeloid leukemia cells addicted to these proteins. In light of these findings, we initiated further pharmacomodulations of 17f to develop new derivatives with enhanced antileukemic activity. Our screening assays identified 14a, an aminopyrimidine derivative of 17f, as a new lead compound that: 1) blocks the growth and survival of myeloid leukemia cells at sub-micromolar concentrations, 2) targets the phosphorylation of STAT5 but also the expression of STAT5B and 3) relieves the resistance of Chronic and Acute Myeloid leukemia cells to conventional chemotherapy.

Downregulation of LncRNA CCAT1 Enhances Chemosensitivity in Cisplatin-Resistant Gastric Cancer Cells.

Chemotherapy is an effective treatment for gastric cancer. However, many patients develop resistance to chemotherapeutic agents during clinical treatment. LncRNA CCAT1 has recently been shown to influence cellular resistance to specific chemotherapeutic drugs, but its role in gastric cancer remains underexplored. This study aims to investigate the role of LncRNA CCAT1 in cisplatin resistance in gastric cancer cells and its potential underlying mechanisms. Gastric cancer cell lines with acquired resistance were established. The expression of CCAT1 was assessed in both cisplatin-sensitive and cisplatin-resistant AGS cell lines. CCAT1 expression was knocked down in AGS/DDP cells, and the changes in IC50 values were measured using the Cell Counting Kit-8 (CCK-8) assay. Apoptosis in gastric cancer cells was evaluated by flow cytometry. Additionally, Western blotting was employed to measure the expression levels of PI3K/AKT/mTORsignaling pathway proteins and apoptosis-related proteins in both interference and control groups. RT-qPCR results indicated that CCAT1 expression was significantly elevated in cisplatin-resistant gastric cancer cells compared to non-resistant cells. Similarly, CCK-8 assay results demonstrated that knocking down CCAT1 in resistant cells increased their sensitivity to cisplatin treatment. Flow cytometry and Western blot results further confirmed that silencing CCAT1 promoted apoptosis in these cells. Additionally, the expression of PI3K/AKT/mTORsignaling pathway proteins was higher in resistant cells compared to their sensitive counterparts, and silencing CCAT1 in AGS/DDP cells resulted in reduced expression of these proteins. In conclusion, the above studies demonstrated that LncRNA CCAT1 induced cisplatin resistance in gastric cancer cells.

Design, synthesis and biological evaluation of novel diaryl-substituted fused nitrogen heterocycles as tubulin polymerization inhibitors to overcome multidrug resistance in vitro and in vivo.

Microtubule-targeting agents (MTAs) are considered as one of the most successful chemotherapy drugs for lung adenocarcinoma (LUAD). However, the clinical application of MTAs is often significantly plagued by multidrug resistance (MDR). To overcome this limitation in the quest of more effective MTAs for tumor therapy, a series of novel diaryl-substituted nitrogenous fused heterocycles were designed, synthesized and evaluated. Through four rounds of structure-activity relationship studies, the benzoimidazole derivative 37 was identified as a potent cytotoxic agent against both paclitaxel-sensitive and -resistant A549 (A549/T) cells, effectively overcoming multidrug resistance of A549/T cells against various MTAs. Mechanistic investigations revealed that 37 could disrupt microtubule assembly and induce cell cycle arrest at the G2/M phase, and hence trigger the cell apoptosis. Furthermore, 37 was found to be a poor substrate for P-glycoprotein (P-gp), a major contributor to multidrug resistance, and could reduce the level of P-gp in resistant cells, thereby effectively overcoming P-gp-mediated multidrug resistance. Notably, 37 exhibited higher liver microsomal stability and better water solubility than those of the reference combretastatin A-4 (CA-4). In vivo studies using an A549/T xenograft model demonstrated that 37 significantly inhibited tumor growth without obvious toxicity, outperforming the positive controls CA-4 and paclitaxel. As a novel tubulin polymerization inhibitor, compound 37 is marked by potent anticancer activity and remarkable anti-MDR properties. These salient features, coupled with the low toxicity of 37, would render it quite promising as a lead for further drug development towards clinical treatment of multidrug-resistant LUAD.

Long noncoding RNA GDIL acts as a scaffold for CHAC1 and XRN2 to promote platinum resistance of colorectal cancer through inhibition of glutathione degradation

Acquired resistance poses a significant obstacle to the effectiveness of platinum-based treatment for cancers. As the most abundant antioxidant, glutathione (GSH) enables cancer cell survival and chemoresistance, by scavenging excessive reactive oxygen species (ROS) induced by platinum. Therapeutic strategy targeting GSH synthesis has been developed, however, failed to produce desirable effects in preventing cancer progression. Thus, uncovering mechanisms of rewired GSH metabolism may aid in the development of additional therapeutic strategies to overcome or delay resistance. Here, we identify upregulation of long noncoding RNA (lncRNA) GDIL (GSH Degradation Inhibiting LncRNA) in platinum resistant colorectal cancer (CRC) and ovarian cancer cells compared with parental ones. High expression of GDIL in resistant CRC is associated with poor survival and hyposensitivity to chemotherapy. We demonstrate that GDIL boosted GSH levels and enhances clearance of ROS induced by platinum. Metabolomic and metabolic flux analysis further reveals that GDIL promotes GSH accumulation by inhibiting GSH degradation. This is attributed by downregulation of CHAC1, an enzyme that specifically degrades intracellular GSH. Mechanistically, GDIL binds and re-localizes the nuclear protein XRN2 to the cytoplasm, where GDIL further serve as a scaffold for XRN2 to identify and degrade CHAC1 mRNA. Suppression of GDIL with selective antisense oligonucleotide, restored drug sensitivity in platinum resistant cell lines and delayed drug resistance in cell line- and patient-derived xenografts. Thus, lncRNA GDIL is a novel target to promote GSH degradation and augment platinum therapy.

Identification of TUBB3 as an immunotherapy target in lung cancer by genome wide in vivo CRISPR screening.

Recent development of immune checkpoint inhibitors has revolutionized cancer immunotherapy. Although these drugs show dramatic effects on a subset of cancer patients, many other tumors are non-responsive and the pathological mechanism of the resistance is largely unknown. To identify genes underlying anti-PD-1 immunotherapy resistance using a systematic approach, we performed an in vivo genome wide CRISPR screening in lung cancer cells. We integrated our results with multi-omics clinical data and performed both in vitro and in vivo assays to evaluate the role of the top candidate in regulating cytotoxic T cell killing. We identified TUBB3 as a potential target to overcome the resistance and enhance the efficacy of anti-PD-1 immunotherapy. TUBB3 expression is upregulated in lung cancer patients, and its higher expression correlates with poorer patients' survival. We found that TUBB3 expression was significantly elevated in the non-responders compared to responders in our patient cohort that received immunotherapies. Importantly, the results of our preclinical experiments showed that inhibition of TUBB3 with a small molecule inhibitor synergized with anti-PD-1 treatment and enhanced tumor cell killing by cytotoxic T cells. Consistently, anti-PD-1 resistant cells showed significantly higher expression of TUBB3; however, TUBB3 inhibition rendered the resistant cells more susceptible to T cell killing. Mechanistic studies revealed that blocking TUBB3 suppressed the expression of PD-L1 through the EMT-related SNAI1 gene. Our results provide a rationale for a novel combination therapy consisting of the TUBB3 inhibition and anti-PD-1 immunotherapy for lung cancer.

A Review on Patient-Derived 3D Micro Cancer Approach for Drug Screen in Personalized Cancer Medicine.

Precision medicine in oncology aims to identify an individualized treatment plan based on genomic alterations in a patient's tumor. It helps to select the most beneficial therapy for an individual patient. As it is now known that no patient's cancer is the same, and therefore, different patients may respond differently to conventional treatments, precision medicine, which replaces the one-size-fits-all approach, supports the development of tailored treatments for specific cancers of different patients. Patient-specific organoid or spheroid models as 3D cell culture models are very promising for predicting resistance to anti-cancer drugs and for identifying the most effective cancer therapy for high-throughput drug screening combined with genomic analysis in personalized medicine. Because tumor spheroids incorporate many features of solid tumors and reflect resistance to drugs and radiation, as in human cancers, they are widely used in drug screening studies. Testing patient-derived 3D cancer spheroids with some anticancer drugs based on information from molecular profiling can reveal the sensitivity of tumor cells to drugs and provide the right compounds to be effective against resistant cells. Given that many patients do not respond to standard treatments, patient-specific treatments will be more effective, less toxic. They will affect survival better compared to the standard approach used for all patients.