Mechanisms of Multidrug Resistance in Cancer Chemotherapy

Alpha-linolenic acid-mediated epigenetic reprogramming of cervical cancer cell lines

Cervical cancer, the fourth most common cancer globally and the second most prevalent cancer among women in India, is primarily caused by Human Papilloma Virus (HPV). The association of diet with cancer etiology and prevention has been well established and nutrition has been shown to regulate cancer through modulation of epigenetic markers. Dietary fatty acids, especially omega-3, reduce the risk of cancer by preventing or reversing the progression through a variety of cellular targets, including epigenetic regulation. In this work, we have evaluated the potential of ALA (α linolenic acid), an ω-3 fatty acid, to regulate cervical cancer through epigenetic mechanisms. The effect of ALA was evaluated on the regulation of histone deacetylases1, DNA methyltransferases 1, and 3b, and global DNA methylation by ELISA. RT-PCR was utilized to assess the expression of tumor regulatory genes (hTERT, DAPK, RARβ, and CDH1) and their promoter methylation in HeLa (HPV18-positive), SiHa (HPV16-positive) and C33a (HPV-negative) cervical cancer cell lines. ALA increased DNA demethylase, HMTs, and HATs while decreasing global DNA methylation, DNMT, HDMs, and HDACs mRNA expression/activity in all cervical cancer cell lines. ALA downregulated hTERT oncogene while upregulating the mRNA expression of TSGs (Tumor Suppressor Genes) CDH1, RARβ, and DAPK in all the cell lines. ALA reduced methylation in the 5' CpG island of CDH1, RARβ, and DAPK1 promoters and reduced global DNA methylation in cervical cancer cell lines. These results suggest that ALA regulates the growth of cervical cancer cells by targeting epigenetic markers, shedding light on its potential therapeutic role in cervical cancer management.

miR‑100: A key tumor suppressor regulatory factor in human malignant tumors (Review)

MicroRNA (miRNA/miR)‑100 is a crucial tumor‑suppressive miRNA that serves a pivotal role in the initiation and progression of various malignancies. miR‑100 regulates cancer cell proliferation, migration, invasion and apoptosis by targeting oncogenes, and acts as a molecular sponge to regulate long non‑coding RNAs and circular RNAs, thereby influencing processes such as glycolysis, autophagy and resistance to chemotherapy/radiotherapy. Furthermore, miR‑100 suppresses tumor progression by modulating key signaling pathways, including the PI3K/AKT and Wnt/β‑catenin signaling pathways. miR‑100 exhibits potential for early cancer diagnosis, particularly in cancer types such as gastric and lung cancer, where it can serve as a non‑invasive biomarker for early screening. As a therapeutic target, restoring miR‑100 expression can enhance the efficacy of chemotherapy or targeted therapy, thereby improving patient prognosis. Although challenges remain in its clinical application, including delivery systems and safety concerns, ongoing research suggests that miR‑100 holds promise for personalized treatment and early diagnosis. Given that cancer remains a global health challenge, research on miR‑100 provides hope for cancer therapy, particularly in China, where the mortality rates of malignancies such as gastric, lung and liver cancer continue to rise, further emphasizing its potential for clinical translation.

Redox-responsive metal-organic framework nanocapsules enhance tumor chemo-immunotherapy by modulating tumor metabolic reprogramming

Immunotherapy, particularly immune checkpoint blockade (ICB), has opened the era of modern oncology, offering significant promise for modern oncology. However, the efficacy of immunotherapy is frequently curtailed by the immunosuppressive tumor microenvironment (ITM), a milieu shaped by tumor metabolic reprogramming. Herein, a novel tumor microenvironment-responsive nanocapsules (DNMCs) were developed that simultaneously modulate tumor metabolism and the ITM to enhance the effectiveness of chemo-immunotherapy. DNMCs consist of an acidic and redox-sensitive metal-organic framework (MOF) encapsulating Doxorubicin (DOX) and the indoleamine-2,3-dioxygenase1 (IDO1) inhibitor NLG919. In the tumor microenvironment, DNMCs degrade, rapidly releasing DOX and NLG919. DOX induces immunogenic cell death (ICD), while NLG919 regulates amino acid metabolism by modulating IDO1 activity, thereby reversing the immunosuppressive of ITM. Consequently, DNMCs elicit effective anti-tumor immune responses, characterized by an increased density of tumor-infiltrating CD8+ cytotoxic T cells as well as depletion of immunosuppressive regulatory T cells (Tregs), thus effectively suppressing pancreatic cancer growth in KPC mice through combined chemo-immunotherapy. Overall, DNMCs exhibit significant tumor growth inhibition in pancreatic cancer patient-derived organoids (PDOs) and mouse models. This study presents a promising approach to enhancing chemo-immunotherapy by targeting tumor metabolic reprogramming and augmenting immune response against malignant tumors.

Current landscape of metal-organic framework-mediated nucleic acid delivery and therapeutics

Nucleic acid drugs utilize DNA or RNA molecules to modulate abnormal gene expression or protein translation in cells, enabling precise treatment for specific conditions. In recent years, nucleic acid drugs have demonstrated tremendous potential in vaccine development and treating genetic disorders. Currently, the primary carriers for clinically approved nucleic acid therapies include lipid nanoparticles and viral vectors. Beyond that, metal-organic frameworks (MOFs) are highly ordered, porous nanomaterials formed through the self-assembly of metal ions and organic ligands via coordination bonds. Their porosity structure offers great loading efficiency, stability, tunability, and biocompatibility, making them an attractive option for nucleic acid delivery. Given the research on MOFs as nucleic acid carriers has garnered significant attention in recent years, this review provides an overview of the therapeutic strategies and advancements in MOF-mediated nucleic acid delivery. The unique properties of various MOF carriers are introduced, and different approaches for nucleic acid loading are parallelly compared. Moreover, a systematic classification based on the type of nucleic acid cargo loaded in MOFs and corresponding applications is thoroughly described. This summary outlines the unique mechanisms through MOFs enhance nucleic acid delivery and emphasizes their substantial impact on therapeutic efficacy. In addition, the utilization of MOF-mediated nucleic acid treatment in combination with other therapies against malignant tumors is discussed in particular. Finally, an outlook on the challenges and potential opportunities of this technology in future translational production and clinical implementation is presented and explored.

LncRNA HOTAIR regulates the expression of MRP1 gene through the mir-6807-5p/Egr1 axis to affect the multidrug resistance of lung cancer cells

Multi-drug resistance-associated protein 1 (MRP1) plays critical roles in the multi-drug resistance (MDR) of cancer cells, LncRNA HOTAIR is closely related to MDR in lung cancer, however, the effects of HOTAIR on MRP1 expression and MDR in lung cancer cells (A549/DDP) remain unknown. In this study, the effects of HOTAIR on MRP1 gene expression and MDR in A549/DDP cells were monitored. LncRNA HOTAIR was upregulated in A549/DDP cells, and overexpression of HOTAIR promoted MRP1 expression and MDR development. The opposite trend was observed when HOTAIR was silenced in A549/DDP cells. To uncover the role of LncRNA HOTAIR in the MDR of human lung cancer, the effects of Egr1 on MRP1 gene expression and MDR in A549/DDP cells were monitored. The results showed that Egr1 could bind to the MRP1 promoter at site -53/-42 bp and regulate MRP1 expression. Egr1 knock-down reduced MRP1 expression, while Egr1 overexpression increased it. Further, the results demonstrated that LncRNA HOTAIR mediated the effects of Egr1 on MRP1 and MDR via sponging of miR-6807-3p. Moreover, miR-6807-3p exerts its function by targeting the Egr1 3'UTR. In conclusion, the results revealed the novel HOTAIR/miR-6807-3p/Egr1 axis in the regulation of MRP1 expression and MDR in lung cancer cells.

Self-assembled HO-1i-Pt(IV) nanomedicine targeting p38/MAPK and MDR pathways for cancer chemo-immunotherapy

Platinum(II)-based antitumor drugs are widely used in clinics but limited by severe side effects and resistance. Multi-target Platinum(IV) complexes are emerging as ideal alternatives. Heme oxygenase-1 (HO-1) works as a rate-limiting step in heme degradation and is overexpressed in malignant tumors. Herein, HO-1i-based Platinum(IV) prodrugs are prepared and candidate complex 15 is further developed into self-assembled nanoparticles (15-NPs). 15 and 15-NPs significantly increase cytotoxicity, particularly in HepG2 (74.77- and 96.14-fold increases) and A549cisR (38.6- and 47.24-fold increases), while reducing toxicity towards normal cells compared to cisplatin. In vitro experiments show 15 and 15-NPs activated multiple pathways, including p38/MAPK- and MDR-related proteins, achieving multi-target synergistic chemosensitization and anti-resistance, further verified by RNA-sequencing analysis. In vivo tests demonstrate that 15 and 15-NPs efficiently inhibit tumor growth and systemic toxicity, especially 15-NPs with optimal tumor-inhibition rate and survival (80% and 100%), superior to cisplatin (40% and 50%), attributing to its extra endocytosis, EPR effect, and precisely tumor-targeted release besides the advantage of a free HO-1i-Pt(IV) prodrug. Additionally, 15 and 15-NPs distinctly regulate T-cell and macrophage functions, thereby exhibiting a chemoimmuno-combined action. This study highlights that multi-functional Platinum(IV) prodrug target-delivered to tumors via carrier-free nanoparticles may represent an effective modality for improving cancer therapy.

Polyploid cancer cells reveal signatures of chemotherapy resistance

Therapeutic resistance in cancer significantly contributes to mortality, with many patients eventually experiencing recurrence after initial treatment responses. Recent studies have identified therapy-resistant large polyploid cancer cells in patient tissues, particularly in late-stage prostate cancer, linking them to advanced disease and relapse. Here, we analyzed bone marrow aspirates from 44 advanced prostate cancer patients and found the presence of circulating tumor cells with increased genomic content (CTC-IGC) was significantly associated with poorer progression-free survival. Single cell copy number profiling of CTC-IGC displayed clonal origins with typical CTCs, suggesting complete polyploidization. Induced polyploid cancer cells from PC3 and MDA-MB-231 cell lines treated with docetaxel or cisplatin were examined through single cell DNA sequencing, RNA sequencing, and protein immunofluorescence. Novel RNA and protein markers, including HOMER1, TNFRSF9, and LRP1, were identified as linked to chemotherapy resistance. These markers were also present in a subset of patient CTCs and are associated with recurrence in public gene expression data. This study highlights the prognostic significance of large polyploid tumor cells, their role in chemotherapy resistance, and the expression of markers tied to cancer relapse, offering new potential avenues for therapeutic development.

Exploring miRNA profile associated with cisplatin resistance in ovarian cancer cells

Ovarian cancer is a common and lethal malignancy among women, whereas chemoresistance is one of the major challenges to its treatment and prognosis. Chemoresistance is a multifactorial phenomenon, involving various mechanisms that collectively modify the cell's response to treatment. Among the changes that arise in cells after acquiring chemoresistance is miRNA dysregulation. Here, this study aimed to identify miRNAs expression changes related to cisplatin resistance in ovarian cancer cells. The miRNA expression profiles of a cisplatin-sensitive A2780 cell line and two cisplatin-resistant cell lines, A2780cis and SK-OV-3, were analyzed using PCR array and qPCR. Accordingly, the miRNAs that were differentially expressed were further investigated to identify their biological functions and the target pathways using Gene Ontology (GO) annotation and KEGG pathway analyses. In order to evaluate the clinical significance of the differentially expressed miRNAs, survival analysis was carried out using expression data for ovarian cancer patients available in the Kaplan-Meier (KM) plotter database. The current work demonstrates that Nine miRNAs were found to be upregulated in cells resistant to cisplatin. Clearly, these miRNAs have functions in cell death/survival related processes and treatment response. They may also target pathways involved in treatment response like PI3K-Akt, pathway in cancer and MAPK. Interestingly, High expression of hsa-miR-133b, hsa-miR-512-are, hsa-miR-200b-3p, and hsa-miR-451a is related to poor overall survival in patients diagnosed with ovarian cancer. Our findings suggest that hsa-miR-133b, hsa-miR-512-5p, hsa-miR-200b-3p, and hsa-miR-451a are good candidates for future studies aimed to establishing functional links and exploring therapeutic interventions to overcome cisplatin resistance.

The METTL3/TRAP1 axis as a key regulator of 5-fluorouracil chemosensitivity in colorectal cancer

Colorectal cancer (CRC) remains a significant clinical challenge, with 5-Fluorouracil (5-FU) being the frontline chemotherapy. However, chemoresistance remains a major obstacle to effective treatment. METTL3, a key methyltransferase involved in RNA methylation processes, has been implicated in CRC carcinogenesis. However, its role in modulating CRC sensitivity to 5-FU remains elusive. In this study, we aimed to investigate the role and mechanisms of METTL3 in regulating 5-FU chemosensitivity in CRC cells. Initially, we observed that 5-FU treatment inhibited cell viability and induced apoptosis, accompanied by a reduction in METTL3 expression in HCT-116 and HCT-8 cells. Subsequent assays including drug sensitivity, EdU, colony formation, TUNEL staining, and flow cytometry revealed that METTL3 depletion enhanced 5-FU sensitivity and increased apoptosis induction both in vitro and in vivo. Conversely, METTL3 overexpression conferred resistance to 5-FU in both cell lines. Moreover, knockdown of METTL3 in 5-FU-resistant CRC cell lines HCT-116/FU and HCT-15/FU significantly decreased 5-FU tolerance and induced apoptosis upon 5-FU treatment. Mechanistically, we found that METTL3 regulated 5-FU sensitivity and apoptosis induction by modulating TRAP1 expression. Further investigations using m6A colorimetric ELISA, dot blot, MeRIP-qPCR and RNA stability assays demonstrated that METTL3 regulated TRAP1 mRNA stability in an m6A-dependent manner. Additionally, overexpression of TRAP1 mitigated the cytotoxic effects of 5-FU on CRC cells. In summary, our study uncovers the pivotal role of the METTL3/TRAP1 axis in modulating 5-FU chemosensitivity in CRC. These findings provide new insights into the mechanisms underlying CRC resistance to 5-FU and may offer potential targets for future therapeutic interventions.

Targeting Wnt signaling in cancer drug resistance: Insights from pre-clinical and clinical research

Cancer drug resistance, encompassing both acquired and intrinsic chemoresistance, remains a significant challenge in the clinical management of tumors. While advancements in drug discovery and the development of various small molecules and anti-cancer compounds have improved patient responses to chemotherapy, the frequent and prolonged use of these drugs continues to pose a high risk of developing chemoresistance. Therefore, understanding the primary mechanisms underlying drug resistance is crucial. Wnt proteins, as secreted signaling molecules, play a pivotal role in transmitting signals from the cell surface to the nucleus. Aberrant expression of Wnt proteins has been observed in a variety of solid and hematological tumors, where they contribute to key processes such as proliferation, metastasis, stemness, and immune evasion, often acting in an oncogenic manner. Notably, the role of the Wnt signaling pathway in modulating chemotherapy response in human cancers has garnered significant attention. This review focuses on the involvement of Wnt signaling and its related molecular pathways in drug resistance, highlighting their associations with cancer hallmarks, stemness, and tumorigenesis linked to chemoresistance. Additionally, the overexpression of Wnt proteins has been shown to accelerate cancer drug resistance, with regulation mediated by non-coding RNAs. Elevated Wnt activity reduces cell death in cancers, particularly by affecting mechanisms like apoptosis, autophagy, and ferroptosis. Furthermore, pharmacological compounds and small molecules have demonstrated the potential to modulate Wnt signaling in cancer therapy. Given its impact, Wnt expression can also serve as a prognostic marker and a factor influencing survival outcomes in human cancers.

Recent advances in chemodynamic nanotherapeutics to overcome multidrug resistance in cancers

Multidrug resistance (MDR) has become a major challenge in cancer therapy, it results in the failure of chemotherapy and anticancer drug development. Chemodynamic therapy (CDT), an emerging cancer treatment strategy, has been reported as a novel approach for cancer treatment characterized by low toxicity and minimal side effects. By generating robust cytotoxic hydroxyl radicals (·OH) via Fenton/Fenton-like reaction, CDT may cause cellular damage and oxidative stress-induced cell death. In recent years, many therapies based on CDT and/or combined with other treatment modalities are reported and exhibit exciting treatment efficacy in cancer treatment, such as photothermal therapy, photodynamic therapy, sonodynamic therapy, chemotherapy, starvation therapy and gas therapy etc. These combination therapies exhibit synergistic effects, significantly improving anticancer outcomes compared to CDT alone. Herein, we provide a comprehensive overview of CDT-based strategies in cancer treatment, highlighting developments of CDT and CDT-based combination strategies in tumor therapy, especially in overcoming MDR challenges. Finally, the opportunities and challenges of CDT and CDT-combination therapy in the clinical application are also addressed.

Mast cell activation induced by tamoxifen citrate via MRGPRX2 plays a potential adverse role in breast cancer treatment

Breast cancer is the most common malignant tumor endangering women's life and health. Tamoxifen citrate (TAM) is the first-line drug of adjuvant endocrine therapy for estrogen receptor-positive (ER+) breast cancer patients. Some sporadic cases have described rare adverse reactions of TAM with potentially life-threatening dermatological manifestations, which were associated with skin allergy. Mas related G protein-coupled receptor X2 (MRGPRX2) on human mast cells is the key target for skin allergy. We aimed to investigate the mechanism of TAM-induced allergic reactions and their potential effects on TAM treatment for breast cancer. In our study, TAM can specifically bind with MRGPRX2, which was mainly driven by hydrophobic force. TAM formed hydrogen bonds with TRP243, TRP248, and GLU164 residues in MRGPRX2. TAM induced calcium mobilization and degranulation of mast cells via MRGPRX2. Besides, TAM induced passive cutaneous anaphylaxis and active systemic anaphylaxis in C57BL/6 mice. The release of β-hexosaminidase, histamine, tumor necrosis factor-α, monocyte chemoattractant protein 1, and interleukin-8 were increased by TAM in vitro and in vivo. Furthermore, we found that MCF-7 and T-47D breast cancer cells can recruit mast cells to adjacent cancerous tissues. Besides, mast cell activation induced by TAM via MRGPRX2 significantly promoted the proliferation and migration of MCF-7 and T-47D cells, which can be effectively reversed by mast cell membrane stabilizer clarithromycin and MRGPRX2 silencing. This study proposed an anti-allergic therapeutic strategy for breast cancer treatment with TAM, while also the potential of MRGPRX2 as an adjunctive target.

Breaking barriers: we need a multidisciplinary approach to tackle cancer drug resistance

Most cancer-related deaths result from drug-resistant disease(1,2). However, cancer drug resistance is not a primary focus in drug development. Effectively mitigating and treating drug-resistant cancer will require advancements in multiple fields, including early detection, drug discovery, and our fundamental understanding of cancer biology. Therefore, successfully tackling drug resistance requires an increasingly multidisciplinary approach. A recent workshop on cancer drug resistance, jointly organised by Cancer Research UK, the Rosetrees Trust, and the UKRI-funded Physics of Life Network, brought together experts in cell biology, physical sciences, computational biology, drug discovery, and clinicians to focus on these key challenges and devise interdisciplinary approaches to address them. In this perspective, we review the outcomes of the workshop and highlight unanswered research questions. We outline the emerging hallmarks of drug resistance and discuss lessons from the COVID-19 pandemic and antimicrobial resistance that could help accelerate information sharing and timely adoption of research discoveries into the clinic. We envisage that initiatives that drive greater interdisciplinarity will yield rich dividends in developing new ways to better detect, monitor, and treat drug resistance, thereby improving treatment outcomes for cancer patients.

Chemical Design of Magnetic Nanomaterials for Imaging and Ferroptosis-Based Cancer Therapy

Ferroptosis, an iron-dependent form of regulatory cell death, has garnered significant interest as a therapeutic target in cancer treatment due to its distinct characteristics, including lipid peroxide generation and redox imbalance. However, its clinical application in oncology is currently limited by issues such as suboptimal efficacy and potential off-target effects. The advent of nanotechnology has provided a new way for overcoming these challenges through the development of activatable magnetic nanoparticles (MNPs). These innovative MNPs are designed to improve the specificity and efficacy of ferroptosis induction. This Review delves into the chemical and biological principles guiding the design of MNPs for ferroptosis-based cancer therapies and imaging-guided therapies. It discusses the regulatory mechanisms and biological attributes of ferroptosis, the chemical composition of MNPs, their mechanism of action as ferroptosis inducers, and their integration with advanced imaging techniques for therapeutic monitoring. Additionally, we examine the convergence of ferroptosis with other therapeutic strategies, including chemodynamic therapy, photothermal therapy, photodynamic therapy, sonodynamic therapy, and immunotherapy, within the context of nanomedicine strategies utilizing MNPs. This Review highlights the potential of these multifunctional MNPs to surpass the limitations of conventional treatments, envisioning a future of drug-resistance-free, precision diagnostics and ferroptosis-based therapies for treating recalcitrant cancers.

Host Defense Peptide Mimics Synergize with Pt(IV) Prodrugs for Surmounting Cisplatin Resistance via Selective Cancer Membrane Disruption

Drug resistance has emerged as a great challenge for achieving satisfactory therapeutic efficacy in platinum-based chemotherapy. Specifically, we synthesized a series of host defense peptide mimics with different degrees of polymerization (DP), i.e., poly(ethylene glycol)-poly(2-azepane ethyl methacrylate) (PEG45-PAEMAn, n = 8, 20, 43, 87, and 183), which displayed DP- and pH-dependent plasma membrane-disruptive capability and antitumor activity. Among these, PEG45-PAEMA43 exhibited the highest cytotoxicity at tumor acidity (pH 6.7), selectivity index, and in vivo antitumor activity, and was selected to encapsulate the hydrophobic Pt(IV) prodrug to form the PEG-PAEMA-Pt(IV) nanoprodrug. The nanoprodrug boosted the membrane-disruptive capability and antitumor activity of A549 and cisplatin-resistant A549/DDP cells at tumor acidity. Notably, it exhibited a much higher cellular uptake for A549/DDP cells and in vivo antitumor activity than PEG-PAEMA or cisplatin alone. This indicated that the PEG-PAEMA-Pt(IV) nanoprodrug could break the drug diffusion barrier posed by the cell membrane and disable even reverse efflux resistance.

Contribution and expression of renal drug transporters in renal cell carcinoma

Renal cell carcinoma (RCC) is a common substantive tumor. According to incomplete statistics, RCC incidence accounts for approximately 90% of renal malignant tumors, and is the second most prevalent major malignant tumor in the genitourinary system, following bladder cancer. Only 10%-15% of chemotherapy regimens for metastatic renal cell carcinoma (mRCC) are effective, and mRCC has a high mortality. Drug transporters are proteins located on the cell membrane that are responsible for the absorption, distribution, and excretion of drugs. Lots of drug transporters are expressed in the kidneys. Changes in carrier function weaken balance, cause disease, or modify the effectiveness of drug treatment. The changes in expression of these transporters during cancer pathology results in multi-drug resistance to cancer chemotherapy. In the treatment of RCC, the study of drug transporters helps to optimize treatment regimens, improve therapeutic effects, and reduce drug side effects. In this review, we summarize advances in the role of renal drug transporters in the genesis, progression, and treatment of RCC.

Novel bis-pocket binding aldose reductase inhibitors sensitize MCF-7/ADR cells to doxorubicin in a dual-role manner

Multidrug resistance (MDR) represents a bottleneck in the treatment of breast cancer. Although the potential of aldose reductase inhibitors (ARIs) as sensitizers against MDR has been explored in recent decades, the intrinsic mechanism still needs to be elucidated, and promising agents in the clinic need to be developed. In this study, three novel ARIs (5a-c), characterized by bis-pocket binding, were designed and synthesized. Inhibitory activity is positively correlated with antioxidation and benefits from rigid spacers. Only 5a with less activities in inhibition and antioxidation was demonstrated as a stronger sensitizer against doxorubicin (DOX)-resistant MCF-7 cells (MCF-7/ADR) than epalrestat (EPA). Either 5a or EPA may decrease GSH abundance and increase ROS, Fe2+, and lipid peroxidation levels. The restorative effects of both ARIs may be blocked by N-acetyl cysteine (NAC). These data suggest that both 5a and EPA may restore the sensitivity of MCF-7/ADR cells to DOX by increasing ferroptosis activity. Furthermore, the inhibition of AKR1B1 by 5a, as well as by EPA, dramatically decreased both p-STAT3 and SLC7A11 expression. Gene knockdown of AKR1B1 has the same effects as AKR1B1 inhibition. This evidence indicates that both ARIs can suppress MCF-7/ADR cell growth via the upregulation of ferroptosis activity via the AKR1B1/STAT3/SLC7A11 axis. Additionally, 5a was found to increase the accumulation of intramolecular DOX by inhibiting ABCB1, but EPA did not. These results support that 5a is a promising sensitizing agent against multidrug resistance in breast cancer.

Recent progress in the development of peptide-drug conjugates (PDCs) for cancer therapy

Peptide-drug conjugates (PDCs) are emerging therapeutic agents composed of peptides, linkers, and payloads, which possess favorable targeting capability and can deliver enough payloads to the tumor sites with minimized impact on healthy tissues. However, only a few PDCs have been approved for clinical use so far. To advance the research on PDCs, this review summarizes the approved PDCs, and PDCs in clinical and preclinical stages based on the payload types. Additionally, the biological activity and pharmacokinetic properties of preclinical PDCs are detailedly described. Lastly, the challenges and future development directions of PDCs are discussed. This review aims to inspire insights into the development of PDCs for cancer treatment.

Nanoscale strategies: doxorubicin resistance challenges and enhancing cancer therapy with advanced nanotechnological approaches

Doxorubicin (DOX), an anthracycline, is widely used in cancer treatment by interfering RNA and DNA synthesis. Its broad antitumour spectrum makes it an effective therapy for a wide array of cancers. However, the prevailing drug-resistant cancer has proven to be a significant drawback to the success of the conventional chemotherapy regime and DOX has been identified as a major hurdle. Furthermore, the clinical application of DOX has been limited by rapid breakdown, increased toxicity, and decreased half-time life, highlighting an urgent need for more innovative delivery methods. Although advancements have been made, achieving a complete cure for cancer remains elusive. The development of nanoparticles offers a promising avenue for the precise delivery of DOX into the tumour microenvironment, aiming to increase the drug concentration at the target site while reducing side effects. Despite the good aspects of this technology, the classical nanoparticles struggle with issues such as premature drug leakage, low bioavailability, and insufficient penetration into tumours due to an inadequate enhanced permeability and retention (EPR) effect. Recent advancements have focused on creating stimuli-responsive nanoparticles and employing various chemosensitisers, including natural compounds and nucleic acids, fortifying the efficacy of DOX against resistant cancers. The efforts to refine nanoparticle targeting precision to improve DOX delivery are reviewed. This includes using receptor-mediated endocytosis systems to maximise the internalisation of drugs. The potential benefits and drawbacks of these novel techniques constitute significant areas of ongoing study, pointing to a promising path forward in addressing the challenges posed by drug-resistant cancers.

Magnetic Nanoparticles and Drug Delivery Systems for Anti-Cancer Applications: A Review

Cancer continues to be a prominent fatal health issue worldwide, driving the urgent need for more effective treatment strategies. The pressing demand has sparked significant interest in the development of advanced drug delivery systems for chemotherapeutics. The advent of nanotechnology offers a groundbreaking approach, presenting a promising pathway to revolutionize cancer treatment and improve patient outcomes. Nanomedicine-based drug delivery systems have demonstrated the capability of improving the pharmacokinetic properties and accumulation of chemotherapeutic agents in cancer sites while minimizing the adverse side effects. Despite these advantages, most NDDSs exhibit only limited improvement in cancer treatment during clinical trials. The recent development of magnetic nanoparticles (MNPs) for biomedical applications has revealed a potential opportunity to further enhance the performance of NDDSs. The magnetic properties of MNPs can be utilized to increase the targeting capabilities of NDDSs, improve the controlled release of chemotherapeutic agents, and weaken the chemoresistance of tumors with magnetic hyperthermia. In this review, we will explore recent advancements in research for NDDSs for oncology applications, how MNPs and their properties can augment the capabilities of NDDSs when complexed with them and emphasize the challenges and safety concerns of incorporating these systems into cancer treatment.

Vault Particles in Cancer Progression, Multidrug Resistance, and Drug Delivery: Current Insights and Future Applications

Vault particles (VPs) are highly conserved large ribonucleoprotein complexes found exclusively in eukaryotes. They play critical roles in various cellular processes, but their involvement in cancer progression and multidrug resistance (MDR) is the most extensively studied. VPs are composed of the major vault protein (MVP), vault RNAs (vtRNAs), vault poly (ADP-ribose) polymerase, and telomerase-associated protein-1. These components are involved in the regulation of signaling pathways that affect tumor survival, proliferation, and metastasis. MVP has been associated with aggressive tumor phenotypes, while vtRNAs modulate cell proliferation, apoptosis, and autophagy. VPs also contribute to MDR by sequestering chemotherapeutic agents, altering their accumulation in the nucleus, and regulating lysosomal dynamics. Furthermore, small vault RNA-derived fragments participate in gene silencing and intercellular communication, reinforcing the role of precursors of vtRNAs in cancer development. Beyond their biological roles, VPs present a promising platform for drug delivery, due to their unique ability to encapsulate a wide range of biomolecules and therapeutic agents, followed by controlled release. This review compiles data from PubMed and Scopus, with a literature search conducted up until December 2024, highlighting current knowledge regarding VPs and their crucial involvement in cancer-related mechanisms and their applications in overcoming cancer drug resistance.

Modular functionalization of cellular nanodiscs enables targeted delivery of chemotherapeutics into tumors

The effective delivery of chemotherapeutic drugs to tumor sites is critical for cancer treatment and remains a significant challenge. The advent of nanomedicine has provided additional avenues for altering the in vivo distribution of drug payloads and increasing tumor localization. More recently, cell-derived nanoparticles, with their biocompatibility and unique biointerfacing properties, have demonstrated considerable utility for drug delivery applications. Here, we demonstrate that cell membrane-derived nanodiscs can be employed for tumor-targeted delivery. To bestow active targeting capabilities to the cellular nanodiscs, we utilize a modular functionalization strategy based on the SpyCatcher system. This enables the nanodiscs to be covalently modified with any targeting ligand labeled with a short SpyTag peptide sequence. As a proof-of-concept, a model chemotherapeutic doxorubicin is loaded into nanodiscs functionalized with an affibody targeting epidermal growth factor receptor. The resulting nanoformulation demonstrates strong tumor targeting both in vitro and in vivo, and it is able to significantly inhibit tumor growth in a murine breast cancer model.

3D Bioprinted Multidrug Resistance (MDR)-Dependent Tumor Spheroids

Multidrug resistance (MDR) refers to the ability of cancer cells to resist various anticancer drugs and release them from the cells. This phenomenon is widely recognized as a significant barrier that must be overcome in chemotherapy. MDR varies depending on the number and expression level of the ATP-binding cassette transporter (ABC transporter), which is expressed differently in various cancer cells. Therefore, the dose of anticancer drugs should be adjusted according to the extent of MDR. The demand for drug screening that considers the differences in MDR is increasing in the process of drug discovery. In this study, three types of tumor spheroids were fabricated from HeLa (MRP1-/BCRP-), HepG2 (MRP1+/BCRP-), and A549 cells (MRP1+/BCRP+) using three-dimensional (3D) bioprinting. The fabricated tumor spheroids maintained their own MDR phenotypes. The EC50 values of doxorubicin (DOX) against the three tumor spheroids were more than 2-fold higher than those against the 2D cells. In addition, the EC50 value of DOX against tumor spheroids was proportional to the number of ABC transporters. The EC50 value of DOX against A549 tumor spheroids had the largest value of 9.5 μM among the three spheroids. In addition, the EC50 values of DOX against HepG2 and A549 tumor spheroids were remarkably reduced when they were treated with ABC transporter inhibitors, such as MK-571 against MRP1 and/or NOV against BCRP. These results demonstrate the successful construction of a 3D bioprinting-based screening platform to quantitatively evaluate the anticancer efficacy of chemodrugs, considering the MDR of cancer cells.

Isoquinolinequinone N-oxides with diverging mechanisms of action induce collateral sensitivity against multidrug resistant cancer cells

Multidrug resistance (MDR) is a major challenge in cancer research. Collateral sensitizers, compounds that exploit the enhanced defense mechanisms of MDR cells as weaknesses, are a proposed strategy to overcome MDR. Our previous work reported the synthesis of two novel Isoquinolinequinone (IQQ) N-oxides that induce collateral sensitivity in MDR ABCB1-overexpressing non-small cell lung cancer (NSCLC) and colorectal cancer cells. Herein, we aimed to investigate underlying mechanisms of antitumor and collateral sensitivity activity of these compounds. We evaluated their effect on cancer cell viability, proliferation, cell cycle profile, and studied their cytotoxicity in non-tumorigenic cells. Their antitumor effect was further studied using NSCLC and colorectal cancer MDR spheroids. To understand underlying collateral sensitivity mechanisms, we assessed the effect on rhodamine-123 accumulation, ROS production, GSH/GSSG balance and expression of key proteins associated with metabolism and redox balance. Both compounds reduced the viability of MDR cells, as 2D cultures or as spheroids, without decreasing the growth of a human nontumorigenic cell line, and increased rhodamine-123 accumulation in MDR NCI-H460/R cells. Moreover, RK2 increased ROS, disrupted GSH balance, and altered expression of proteins associated with oxidative stress protection, particularly in NCI-H460/R cells. The collateral sensitivity effect of RK3 could not be attributed to redox balance disruption, but increased IDH1 expression following treatment suggests a potential metabolic shift in MDR cells. These findings highlight RK2 and RK3 as promising candidates for next stages of drug development. Their distinct mechanisms of action could lead to therapeutic solutions for MDR-related cancers, specifically linked to ABCB1 overexpression.

Fucosyltransferase 4 upregulates P-gp expression for chemoresistance via NF-κB signaling pathway

BACKGROUND

Multidrug resistance (MDR) poses a significant obstacle to developing chemotherapeutic treatments. In previous studies using a traditional model of adriamycin resistance (ADR) with K562 cells, we demonstrated that N-acetylglucosaminyltransferase III (GnT-III) expression negatively regulates chemoresistance. Additionally, we observed that fucosylation levels were increased in the ADR cells.

METHOD

Fucosylation levels were determined using lectin blot, western blot, and flow cytometry. Gene expression levels were analyzed via qPCR. We generated a FUT4 knockout (KO) ADR cell line using CRISPR/Cas9 technology. Cytotoxicity and drug efflux assays were conducted to evaluate chemotherapy tolerance.

RESULTS

The expression levels of FUT4 and its products, the LeX antigens, were significantly upregulated in the ADR cells compared to the parental K562 cells. The FUT4 KO reduced the elevated levels of P-glycoprotein (P-gp) found in ADR cells and exhibited increased sensitivity to chemotherapeutic drugs. Furthermore, restoring FUT4 expression in the KO cells effectively reversed P-gp expression, drug efflux, and chemoresistance. Given the critical role of the NF-κB pathway in P-gp expression, we investigated NF-κB signaling and found that the phosphorylation levels of p65 were significantly increased in the ADR cells but were downregulated in the FUT4 KO cells. Furthermore, the restoration of FUT4 rescued the phosphorylation levels of p65.

CONCLUSIONS

FUT4 specifically upregulates P-gp expression related to chemoresistance through the NF-κB signaling pathway.

GENERAL SIGNIFICANCE

This study highlights the importance of FUT4 in chemoresistance and suggests it may serve as a promising target for combating MDR.

Herbal drug‑based nanotherapy for hepatocellular carcinoma: Quercetin‑contained nanocarrier as a multipurpose therapeutic agent against hepatocellular carcinoma (Review)

Cancer remains one of the leading causes of morbidity and mortality worldwide, with hepatocellular carcinoma (HCC) accounting for ~75% of all primary liver cancers and exhibiting a high incidence rate. Unfortunately, the response rate to chemotherapeutic agents for liver cancer is relatively low, primarily due to the development of drug resistance and the lack of targeted therapeutic agents. The present study focused on the anticancer mechanisms of quercetin and the development of innovative nanocarriers designed to enhance its efficacy against HCC while mitigating drug resistance. Quercetin demonstrates a diverse array of biological activities, making it a promising candidate for therapeutic applications. Its mechanisms include inhibition of tumor cell cycle, induction of apoptosis, modulation of reactive oxygen species and inhibition of chemotherapeutic resistance. Given these properties, extensive research has been conducted in pharmaceutical engineering to develop well-designed nanocarriers that incorporate quercetin. These nanocarriers aim to improve the bioavailability and targeting of quercetin, thereby enhancing its therapeutic efficacy against HCC and overcoming the challenges associated with anticancer drug resistance. Through this approach, quercetin could potentially play a pivotal role in the future of HCC treatment, providing a synergistic effect when combined with traditional chemotherapy leading to improved patient outcomes.

Targeted thermosensitive liposomes loaded with gold nanoparticles and temozolomide hexadecanoate for the synergistic photothermal-chemotherapy treatment of glioblastoma

Glioblastoma (GBM) is a highly aggressive malignant brain tumour which presents a significant challenge due to the limited effectiveness of current surgical and chemotherapeutic approaches. In this study, we have developed TMZ16e and gold nanoparticles coencapsulated thermosensitive liposomes modified with anti-EphA3 (anti-EphA3-TMZ16e-GNPs-TSL) delivered via the intranasal route to achieve photothermal chemotherapy (PCT) for improving the therapeutic effects of GBM. The prepared anti-EphA3-TMZ16e-GNPs-TSL were spherical with a particle size of 173.7 ± 1.2 nm with toxicity tests confirming their excellent safety for the nasal mucosa. Furthermore, an elevated temperature (42.2 °C) was observed under 780 nm infrared irradiation, which resulted in the targeted release of TMZ16e. In vitro, cellular assays demonstrated that the cytotoxicity in the anti-EphA3-TMZ16e-GNPs-TSL group were significantly higher (55 %) than other groups upon laser irradiation (p < 0.01). In vivo, thermographic analysis revealed a significant increase in brain temperature (42.4 °C) in the anti-EphA3-TMZ16e-GNPs-TSL group. The combination therapy resulted in a significant increase in tumor cell apoptosis and a median survival time of 47 days, which was 1.38 and 1.68 times longer than that observed in rats treated with chemotherapy or photothermal therapy, respectively. H&E and TUNEL staining results that PCT induce apoptosis in GBM cells. This targeted PCT system represents a promising treatment strategy for GBM, offering a more precise and potent therapeutic intervention that could potentially improve patient prognosis and quality of life.

The association of ABC proteins with multidrug resistance in cancer

Multidrug resistance (MDR) poses one of the primary challenges for cancer treatment, especially in cases of metastatic disease. Various mechanisms contribute to MDR, including the overexpression of ATP-binding cassette (ABC) proteins. In this context, we reviewed the literature to establish a correlation between the overexpression of ABC proteins and MDR in cancer, considering both in vitro and clinical studies. Initially, we presented an overview of the seven subfamilies of ABC proteins, along with the subcellular localization of each protein. Subsequently, we identified a panel of 20 ABC proteins (ABCA1-3, ABCA7, ABCB1-2, ABCB4-6, ABCC1-5, ABCC10-11, ABCE1, ABCF2, ABCG1, and ABCG2) associated with MDR. We also emphasize the significance of drug sequestration by certain ABC proteins into intracellular compartments. Among the anticancer drugs linked to MDR, 29 were definitively identified as substrates for at least one of the three most crucial ABC transporters: ABCB1, ABCC1, and ABCG2. We further discussed that the most commonly used drugs in standard regimens for mainly breast cancer, lung cancer, and acute lymphoblastic leukemia could be subject to MDR mediated by ABC transporters. Collectively, these insights will aid in conducting new studies aimed at a deeper understanding of the clinical MDR mediated by ABC proteins and in designing more effective pharmacological treatments to enhance the objective response rate in cancer patients.

Transferrin-targeting pH-responsive and biodegradable mesoporous silica nanohybrid for nitric oxide-sensitized chemotherapy of cancer

Weakly acidic pH, low oxygen and high glutathione levels are the main characteristics of tumor cells. Taking advantage of the unique acidic microenvironment of tumor cells, acid-responsive mesoporous organosilica nanoparticles (AMON) were designed for nitric oxide (NO)-sensitized chemotherapy of tumors. AMON served as a nanocarrier co-loaded with a nitric oxide donor (NOD) and chemotherapeutic drug doxorubicin (DOX). Transferrin (Tf) was modified on the surface as a targeting ligand to form NOD&DOX@AMON. In vitro experiments showed that AMON could be completely degraded under acidic conditions (pH 5.0) after 48 h. NOD&DOX@AMON entered cells via transferrin receptor-mediated internalization and degraded in the acidic microenvironment to release its payloads. NOD released NO in presence of one-electron reducing substances like Glutathione (GSH) and ascorbic acid, inhibiting P-glycoprotein(P-gp) function and thereby increasing the intracellular concentration of DOX. In vivo distribution studies revealed that the nanohybrids accumulated maximally in tumor tissue 12 h after intravenous injection and exhibited significant inhibitory effects on HepG2 xenograft tumors. Western blot experiments demonstrated that NOD&DOX@AMON could inhibit the expression of drug resistance-associated proteins and was expected to be employed as a therapeutic approach for drug-resistant ttumors.

Combating tumor PARP inhibitor resistance: Combination treatments, nanotechnology, and other potential strategies

PARP (poly (ADP-ribose) polymerase) inhibitors (PARPi) have demonstrated significant potential in cancer treatment, particularly in tumors with breast cancer susceptibility gene (BRCA) mutations and other DNA repair deficiencies. However, the development of resistance to PARPi has become a major challenge in their clinical application. The emergence of drug resistance leads to reduced efficacy of the PARPi over time, impacting long-term treatment outcomes and survival rates. PARPi resistance in tumors often arises as cells activate alternative DNA repair pathways or evade the effect of PARPi, diminishing therapeutic effectiveness. Consequently, overcoming resistance is crucial for maintaining treatment efficacy and improving patient prognosis. This paper reviews the strategies to overcome PARPi resistance through combination treatment and nanotechnology therapy. We first review the current combination therapies with PARPi, including anti-angiogenic therapies, radiotherapies, immunotherapies, and chemotherapies, and elucidate their mechanisms for overcoming PARPi resistance. Additionally, this paper focuses on the application of nanotechnology in improving the effectiveness of PARPi and overcoming drug resistance. Subsequently, this paper presents several promising strategies to tackle PARPi resistance, including but not limited to: structural modifications of PARPi, deployment of gene editing systems, implementation of "membrane lipid therapy," and modulation of cellular metabolism in tumors. By integrating these strategies, this research will provide comprehensive approaches to overcome the resistance of PARPi in cancer treatment and offer guidance for future research and clinical practice.

Investigating the role of exosomal long non-coding RNAs in drug resistance within female reproductive system cancers

Exosomes, as key mediators of intercellular communication, have been increasingly recognized for their role in the oncogenic processes, particularly in facilitating drug resistance. This article delves into the emerging evidence linking exosomal lncRNAs to the modulation of drug resistance mechanisms in cancers such as ovarian, cervical, and endometrial cancer. It synthesizes current research findings on how these lncRNAs influence cancer cell survival, tumor microenvironment, and chemotherapy efficacy. Additionally, the review highlights potential therapeutic strategies targeting exosomal lncRNAs, proposing a new frontier in overcoming drug resistance. By mapping the interface of exosomal lncRNAs and drug resistance, this article aims to provide a comprehensive understanding that could pave the way for innovative treatments and improved patient outcomes in female reproductive system cancers.

Cellular Systems for Colorectal Stem Cancer Cell Research

Oncological diseases consistently occupy leading positions among the most life-threatening diseases, including in highly developed countries. At the same time, the second most common cause of cancer death is colorectal cancer. The current level of research shows that the development of effective therapy, in this case, requires a new grade of understanding processes during the emergence and development of a tumor. In particular, the concept of cancer stem cells that ensure the survival of chemoresistant cells capable of giving rise to new tumors is becoming widespread. To provide adequate conditions that reproduce natural processes typical for tumor development, approaches based on increasingly complex cellular systems are being improved. This review discusses the main strategies that allow for the study of the properties of tumor cells with an emphasis on colorectal cancer stem cells. The features of working with tumor cells and the advantages and disadvantages of 2D and 3D culture systems are considered.

Role of PARP-1 structural and functional features in PARP-1 inhibitors development

Poly(ADP-ribose) polymerase-1 (PARP-1) is the key enzyme among other PARPs for post-translational modification of DNA repair proteins. It has four functional domains for DNA-binding, automodification and enzymatic activity. PARP-1 participates in poly-ADP-ribosylation of itself or other proteins during DNA damage response. It recruits reparation machinery proteins that restore native DNA sequence. PARP-1 participates in chromatin structure organization and gene expression regulation. It was shown that PARP-1-dependent regulation mechanisms affect on possible risk of carcinogenesis. Therefore, PARP-1 was proposed as a novel target for cancer treatment. Three generations of PARP-1 inhibitors had been developed depending on pharmacophore structure. To date, four PARP-1 inhibitors have been approved for cancer treatment as a chemotherapy potentiators or as a stand-alone therapy. However, different cytotoxicity effects of specific PARP-1 inhibitors were observed due to diverse PARP-1 activity in cellular processes. Moreover, cancer cells can develop resistance to PARP-1 inhibitors and decrease chemotherapy efficacy. There are promising strategies how to avoid these disadvantages including dual-targeted inhibitors and combination therapy.

Tailoring traditional Chinese medicine in cancer therapy

Cancer remains a formidable global health challenge, necessitating innovative therapeutic approaches to enhance treatment efficacy and reduce adverse effects. The traditional Chinese medicine (TCM), as an embodiment of ancient wisdom, has been validated to regulate the holistic human capacity against both internal and external "evils" in accordance with TCM principles. Therefore, it stands to reason to integrate TCM into current cancer therapy paradigms, such as chemotherapy, immunotherapy, and targeted therapy. This strategy conceptually intends to circumvent the inevitable side effects derived from present treatment, alleviate the discomfort, mollify the detrimental mood and synergize tumoricidal effects of distinct approaches. However, it is still vague whether TCM exert favorable function in cancer treatment. Therefore, it is imperative to retrieve and compile the existing literature on TCM in the realm of cancer, followed by a comprehensive recapitulation and synthesis of its core findings. Recently, with the advancement of contemporary biologic and medical theory and technology, it has become both feasible and imperative to elucidate the molecular signaling mechanisms and cellular biology underlying TCM. Specifically, leveraging TCM pharmaceutic components can not only directly impact tumor biology at the molecular level, but regulate the tumor immune environment through distinct pathways. Additionally, the administration of external TCM treatments such as acupuncture and moxibustion also demonstrates beneficial effects in cancer patients. Through comprehensive analysis, we demonstrated that TCM not only potentially increases the efficacy of conventional cancer treatments, but also significantly mitigates their toxic side effects, thereby prolonging patients' prognosis and improving their living quality. Furthermore, we have underscored the challenges and prospects associated with the integration of TCM into contemporary oncological practices, placing particular emphasis on the imperative for rigorous clinical trials and molecular investigations to substantiate the efficacy and safety of these combined therapeutic approaches. This synthesis aims to pave the way for a more integrated approach to cancer treatment rooted in both traditional wisdom and cutting-edge science.

GRP78 as a potential therapeutic target in cancer treatment: an updated review of its role in chemoradiotherapy resistance of cancer cells

GRP78 (Glucose-related protein 78, BiP/HSPA5) is commonly overexpressed in cancer cells. Acting as an activator of endoplasmic reticulum stress, GRP78 is involved in the resistance of cancer cells to injury. Current evidence suggests that GRP78 plays a significant role in the radiotherapy resistance and chemotherapy resistance of cancers, which is accomplished through a variety of complex pathways. These include the promotion of tumor stemness, inhibition of apoptosis, regulation of autophagy, maintenance of tumor microenvironment homeostasis, protection of dormant cells, evasion of senescence, counteraction of autoantibodies against GRP78, facilitation of DNA damage repair, suppression of ferroptosis, and modulation of metabolic reprogramming in tumor cells. Importantly, chemoradiotherapy resistance in cancers are the main reasons for treatment failure in patients, severely affecting their survival. Investigating the mechanisms of GRP78 in tumor therapeutic resistance is essential. In this article, we review the mechanisms by which GRP78 mediates cell survival and chemoradiotherapy resistance in cancers and provide an overview of clinical trials targeting GRP78 therapy.

In vitro and in silico hybrid approach to unveil triterpenoids from Helicteres hirsuta leaves as potential compounds for inhibiting Nrf2

Cancer is a leading global health concern, with over 20 million new cases and 9.7 million deaths reported in 2022. Chemotherapy remains a widely used treatment, but drug resistance, which affects up to 90% of treatment outcomes, significantly hampers its effectiveness. The transcription factor Nrf2, which is crucial for cellular defense against oxidative stress, plays a dual role in cancer treatment. Although Nrf2 activation can suppress early carcinogenesis, its overexpression in cancer cells contributes to drug resistance, resulting in poor patient outcomes. Thus, inhibiting Nrf2 has emerged as a promising strategy for overcoming cancer drug resistance. Natural compounds such as luteolin and brusatol have shown potential in inhibiting Nrf2, although with limitations. This study isolates and characterizes seven triterpenoids from the n-hexane sub-fraction of Helicteres hirsuta, a plant traditionally used for medicinal purposes, to evaluate their ability to modulate Nrf2 activity in Huh7 cancer and HaCaT normal cells. Additionally, molecular docking and dynamic simulations were utilized to assess the binding potential of these compounds to the PI3Kα receptor, which regulates downstream signaling pathways, thereby suppressing Nrf2 activity in cancer cells. Our findings provide insights into new strategies seeking triterpenoids as promising structures to reverse chemoresistance by regulating Nrf2. The results also reveal the potential of 3β-O-trans-caffeoylbetulinic acid from H. hirsuta leaves as the unprecedented compound inhibiting Nrf2 activity, with an IC50 of 74.5 μg mL-1 in Huh7 cancer cells.

Design, synthesis and biological evaluation of biaryl amide derivatives as modulators of multi-drug resistance

The emergence of multi-drug resistance (MDR) presents a significant impediment to the efficacy of cancer treatment. Aberrant expression of ABC (ATP-binding cassette) transporters is acknowledged as one of the underlying factors contributing to MDR. P-glycoprotein (P-gp, MDR1, ABCB1), breast cancer resistance protein (BCRP, ABCG2), and MDR-associated protein 1 (MRP1, ABCC1) are members of the ABC transporter, and their over-expression usually occurs in drug-resistant tumor cells. In this work, the structure-activity relationships of the biaryl amide skeleton were systematically investigated via structural optimization step by step, which led to the identification of an exceptionally potent resistance reversal agent, D2. Compound D2 effectively reversed MDR to paclitaxel and cisplatin in A2780/T, A2780/CDDP and A549/T cell lines. It could directly bind to P-gp and downregulate the expression of both P-gp and MRP1. The treatment with D2 increased the intracellular accumulation of Rh123 and inhibited P-gp-mediated drug efflux of Rh123 in A2780/T cells. Therefore, compound D2 exhibits promising potential in overcoming multidrug resistance (MDR) induced by P-gp in cancer.

MiRNAs: main players of cancer drug resistance target ABC transporters

Chemotherapy remains the cornerstone of cancer treatment; however, its efficacy is frequently compromised by the development of chemoresistance. Multidrug resistance (MDR), characterized by the refractoriness of cancer cells to a wide array of chemotherapeutic agents, presents a significant barrier to achieving successful and sustained cancer remission. One critical factor contributing to this chemoresistance is the overexpression of ATP-binding cassette (ABC) transporters. Furthermore, additional mechanisms, such as the malfunctioning of apoptosis, alterations in DNA repair systems, and resistance mechanisms inherent to cancer stem cells, exacerbate the issue. Intriguingly, microRNAs (miRNAs) have demonstrated potential in modulating chemoresistance by specifically targeting ABC transporters, thereby offering promising new avenues for overcoming drug resistance. This narrative review aims to elucidate the molecular underpinnings of drug resistance, with a particular focus on the roles of ABC transporters and the regulatory influence of miRNAs on these transporters.

Evolutionary rescue model informs strategies for driving cancer cell populations to extinction

Cancers exhibit a remarkable ability to develop resistance to a range of treatments, often resulting in relapse following first-line therapies and significantly worse outcomes for subsequent treatments. While our understanding of the mechanisms and dynamics of the emergence of resistance during cancer therapy continues to advance, questions remain about how to minimize the probability that resistance will evolve, thereby improving long-term patient outcomes. Here, we present an evolutionary simulation model of a clonal population of cells that can acquire resistance mutations to one or more treatments. We leverage this model to examine the efficacy of a two-strike "extinction therapy" protocol, in which two treatments are applied sequentially to first contract the population to a vulnerable state and then push it to extinction, and compare it to a combination therapy protocol. We investigate how factors such as the timing of the switch between the two strikes, the rate of emergence of resistant mutations, the doses of the applied drugs, the presence of cross-resistance, and whether resistance is a binary or a quantitative trait affect the outcome. Our results show that the timing of switching to the second strike has a marked effect on the likelihood of driving the cancer to extinction, and that extinction therapy outperforms combination therapy when cross-resistance is present. We conduct an in silico trial that reveals when and why a second strike will succeed or fail. Finally, we demonstrate that our conclusions hold whether we model resistance as a binary trait or as a quantitative, multi-locus trait.

Expression of ABCB1, ABCC1, and LRP in Mesenchymal Stem Cells from Human Amniotic Fluid and Bone Marrow in Culture-Effects of In Vitro Osteogenic and Adipogenic Differentiation

Mesenchymal stem cells (MSCs) are multipotent cells with the potential to differentiate into various lineages. They have also the potential to protect themselves against harmful stimuli to maintain their functional integrity. Drug resistance-related transporters such as ABCB1 (P-glycoprotein; P-gp), ABCC1 (MRP1; multidrug resistance-related Protein 1), and LRP (lung resistance protein) may protect MSCs against toxic substances such as chemotherapeutic agents. This study evaluated ABCB1, ABCC1, and LRP before and after the differentiation of MSCs derived from human amniotic fluid (AF) and bone marrow (BM). P-gp expression in both AFMSCs and BMMSCs was analyzed by immunocytochemistry, and pump function was analyzed by cell viability assay with doxorubicin (DOX) and Rhodamine 123 (Rh 123) dye exclusion. ABCB1, ABCC1, and LRP gene expression was determined by RT-PCR both before and after osteogenic and adipogenic differentiation. The MES-SA/DX5 cell line was used as a model of resistance to DOX and the overexpression of P-gp. Both AFMSCs and BMMSCs displayed a high P-gp expression, although lower than MES-SA/DX5 control cells. It was shown that both, undifferentiated AFMSCs and BMMSCs, have high cell viability in response to DOX, similar to the MES-SA/DX5 lineage. ABCB1 was less expressed in BM than in AFMSCs in undifferentiated samples, while no differences were observed in the expression of ABCC1 and LRP. AFMSCs showed an increase in ABCB1 after osteogenic differentiation, whereas BMMSCs exhibited lower ABCB1 and ABCC1 expression after osteogenic and adipogenic differentiation. The findings suggest that ABCB1, ABCC1, and LRP gene expression in AFMSCs and BMMSCs is influenced by differentiation processes and further support the concept that these transporters modulate MSC differentiation in a cell source-dependent way.

Evaluation of anticancer efficacy of survivin si-RNA functionalized combined drug-loaded mesoporous silica nanoparticles in a lung cancer mouse model

Lung cancer continues to be the leading cause of mortality globally. Nanotechnology-mediated targeted drug delivery approach is one of the promising strategies for the treatment of lung cancer. Due to their multifactorial role, mesoporous silica nanoparticles (MSNs), have attracted a lot of attention for drug delivery. The emerging dual-drug co-delivery approach has drawn much attention due to circumventing various drug-resistant mechanisms in tumor cells. Further, functionalization of si-RNA (survivin) to the dual drugs (etoposide plus carfilzomib) or (docetaxel plus carfilzomib) loaded MSNs can be a potential tool to inhibit gene expression specifically. In the present study, we investigated the comparative therapeutic efficacy of co-delivered anticancer drugs functionalized with survivin siRNA in MSNs for lung cancer. According to our findings, this kind of combination therapy has inhibited the function of the survivin protein while promoting increased therapeutic efficacy due to synergistic pharmacological activity, and found si-RNA- (etoposide plus carfilzomib) to be a better candidate for lung cancer treatment in the future.

In vitro models to evaluate multidrug resistance in cancer cells: Biochemical and morphological techniques and pharmacological strategies

The overexpression of ATP-binding cassette (ABC) transporters contributes to the failure of chemotherapies and symbolizes a great challenge in oncology, associated with the adaptation of tumor cells to anticancer drugs such that these transporters become less effective, a mechanism known as multidrug resistance (MDR). The aim of this review is to present the most widely used methodologies for induction and comprehension of in vitro models for detection of multidrug-resistant (MDR) modulators or inhibitors, including biochemical and morphological techniques for chemosensitivity studies. The overexpression of MDR proteins, predominantly, the subfamily glycoprotein-1 (P-gp or ABCB1) multidrug resistance, multidrug resistance-associated protein 1 (MRP1 or ABCCC1), multidrug resistance-associated protein 2 (MRP2 or ABCC2) and cancer resistance protein (ABCG2), in chemotherapy-exposed cancer lines have been established/investigated by several techniques. Amongst these techniques, the most used are (i) colorimetric/fluorescent indirect bioassays, (ii) rhodamine and efflux analysis, (iii) release of 3,30-diethyloxacarbocyanine iodide by fluorescence microscopy and flow cytometry to measure P-gp function and other ABC transporters, (iv) exclusion of calcein-acetoxymethylester, (v) ATPase assays to distinguish types of interaction with ABC transporters, (vi) morphology to detail phenotypic characteristics in transformed cells, (vii) molecular testing of resistance-related proteins (RT-qPCR) and (viii) 2D and 3D models, (ix) organoids, and (x) microfluidic technology. Then, in vitro models for detecting chemotherapy MDR cells to assess innovative therapies to modulate or inhibit tumor cell growth and overcome clinical resistance. It is noteworthy that different therapies including anti-miRNAs, antibody-drug conjugates (to natural products), and epigenetic modifications were also considered as promising alternatives, since currently no anti-MDR therapies are able to improve patient quality of life. Therefore, there is also urgency for new clinical markers of resistance to more reliably reflect in vivo effectiveness of novel antitumor drugs.

Photodynamic priming modulates cellular ATP levels to overcome P-glycoprotein-mediated drug efflux in chemoresistant triple-negative breast cancer

P-glycoprotein (P-gp, ABCB1) is a well-researched ATP-binding cassette (ABC) drug efflux transporter linked to the development of cancer multidrug resistance (MDR). Despite extensive studies, approved therapies to safely inhibit P-gp in clinical settings are lacking, necessitating innovative strategies beyond conventional inhibitors or antibodies to reverse MDR. Photodynamic therapy is a globally approved cancer treatment that uses targeted, harmless red light to activate non-toxic photosensitizers, confining its cytotoxic photochemical effects to disease sites while sparing healthy tissues. This study demonstrates that photodynamic priming (PDP), a sub-cytotoxic photodynamic therapy process, can inhibit P-gp function by modulating cellular respiration and ATP levels in light accessible regions. Using chemoresistant (VBL-MDA-MB-231) and chemosensitive (MDA-MB-231) triple-negative breast cancer cell lines, we showed that PDP decreases mitochondrial membrane potential by 54.4% ± 30.4 and reduces mitochondrial ATP production rates by 94.9% ± 3.46. Flow cytometry studies showed PDP can effectively improve the retention of P-gp substrates (calcein) by up to 228.4% ± 156.3 in chemoresistant VBL-MDA-MB-231 cells, but not in chemosensitive MDA-MB-231 cells. Further analysis revealed that PDP did not alter the cell surface expression level of P-gp in VBL-MDA-MB-231 cells. These findings indicate that PDP can reduce cellular ATP below the levels that is required for the function of P-gp and improve intracellular substrate retention. We propose that PDP in combination with chemotherapy drugs, might improve the efficacy of chemotherapy and overcome cancer MDR.

c-MET tyrosine kinase inhibitors reverse drug resistance mediated by the ATP-binding cassette transporter B1 (ABCB1) in cancer cells

This study investigated the potential of MET kinase inhibitors, cabozantinib, crizotinib, and PHA665752, in reversing multidrug resistance (MDR) mediated by ABCB1 in cancer cells. The accumulation of the fluorescent probe, Rhodamine 123, was assessed using flow cytometry and fluorescence microscopy in MDR MES-SA/DX5 and parental cells. The growth inhibitory activity of MET inhibitors as monotherapies and in combination with chemotherapeutic drugs was evaluated by MTT assay. CalcuSyn software was used to analyze the combination index (CI) as an index of drug-drug interaction in combination treatments. Results showed that at concentrations of 5, and 25 μM, c-MET inhibitors significantly increased Rhodamine 123 accumulation in MDR cells, with ratios up to 17.8 compared to control cells, while exhibiting no effect in parental cells. Additionally, the combination of c-MET inhibitors with the chemotherapeutic agent doxorubicin synergistically enhanced cytotoxicity in MDR cells, as evidenced by combination index (CI) values of 0.54 ± 0.08, 0.69 ± 0.1, and 0.85 ± 0.07 for cabozantinib, crizotinib, and PHA665752, respectively. While all three c-MET inhibitors stimulated ABCB1 ATPase activity in different manners at certain concentrations, PHA-665752 suppressed it at high concentration. In silico analysis also suggested that the transmembrane domains (TMD) of ABCB1 transporters could be considered potential target for these agents. Our results suggest that c-MET inhibitors can serve as promising MDR reversal agents in ABCB1-medicated drug-resistant cancer cells.

Synthesis and Characterization of Acacia-Stabilized Doxorubicin-Loaded Gold Nanoparticles for Breast Cancer Therapy

The targeted delivery of drugs is vital in breast cancer treatment due to its ability to produce long-lasting therapeutic effects with minimal side effects. This study reports the successful development of doxorubicin hydrochloride (DOX)-loaded colloidal gold nanoparticles stabilized with acacia gum (AG). Optimization studies varied AG concentrations (0.25% to 3% w/v) to determine optimal conditions for nanoparticle synthesis. The resulting acacia stabilized gold nanoparticles (AGNPs) were characterized using various techniques including high-resolution transmission electron microscopy (HR-TEM), powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), ultraviolet-visible spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM), and selected area electron diffraction (SAED). In vitro drug release studies demonstrated a higher release rate of DOX in sodium acetate buffer (pH 5.0) compared to phosphate buffer saline (pH 7.4), suggesting an enhanced therapeutic efficacy in acidic tumor environments. Cytotoxicity of DOX-AGNPs and free DOX was assessed in human breast cancer cells (MDA-MB-231). The DOX-AGNPs exhibited significantly greater cytotoxicity, indicating enhanced efficacy in targeting cancer cells. This enhancement suggests that adsorbing DOX on the surface of gold nanoparticles can improve drug delivery and effectiveness, potentially reducing side effects compared to pure DOX and traditional delivery methods. Stability tests conducted over six months at 25±1°C showed significant changes in particle size and PDI, suggesting limited stability under these conditions. Overall, the acacia-stabilized gold nanoparticles synthesized in this study exhibit promising characteristics for drug delivery applications, particularly in cancer therapy, with effective drug loading, controlled release, and favorable physicochemical properties.

Treatment of stage IV colorectal cancer: A retrospective cohort study assessing whether failure of first‑line treatment indicates failure of second‑line treatment

Colorectal cancer (CRC) is one of the most frequent malignancies and, despite screening programs, it is often diagnosed at late stages. Although current first- and second-line therapies stratify for KRAS/NRAS/BRAF mutations, microsatellite instability, tumour location and co-morbidities, the therapeutic mainstay for the first- and second-line treatment of the majority of patients consists of 5-fluorouracil (5-FU)-based chemo-immunotherapy. The present study evaluated the responses of patients with stage IV CRC, treated at the University Hospital Krems between January 1, 2015 and December 31, 2021, who received at least two therapy lines (n=49), with the aim of investigating whether the response to first-line therapy could predict the response to second-line therapy. All patients with first-line complete response (CR) had at least stable disease in response to second-line treatment [overall response rate (ORR)=66.6%]. On the other hand, all patients with progressive disease (PD) in response to first-line treatment (n=7) did not respond to second-line therapy (ORR=0%). These findings also translated to overall survival (OS): Patients with first-line CR had a median OS time of 80 months, whereas patients with PD had a median OS time of 12 months (P<0.001). Furthermore, different parameters were analysed for their impact on OS; the results revealed that BRAF alterations were associated with poor prognosis. Other factors (sex, tumor sidedness, KRAS and MSS/MSI status) had in this cohort no significant effect on OS. In conclusion, the present study demonstrated that, with current treatment strategies applying 5-FU-based chemo-immunotherapy as first- and second-line treatment for patients with metastatic CRC, response to first-line therapy may be a strong predictor for the response to second-line therapy and OS. By exchanging the chemotherapeutic combination partner from oxaliplatin to irinotecan or vice versa, plus the additive anti-epidermal growth factor receptor/anti-vascular endothelial growth factor antibody, the negative factor of non-response to first-line therapy could not be overcome by second-line treatment in this study population. These findings must be confirmed in larger studies, but indicate the need for novel treatment options, especially for patients not responding to first-line 5-FU-based chemo-immunotherapy.

Metabolism of cancer cells and immune cells in the initiation, progression, and metastasis of cancer

The metabolism of cancer and immune cells plays a crucial role in the initiation, progression, and metastasis of cancer. Cancer cells often undergo metabolic reprogramming to sustain their rapid growth and proliferation, along with meeting their energy demands and biosynthetic needs. Nevertheless, immune cells execute their immune response functions through the specific metabolic pathways, either to recognize, attack, and eliminate cancer cells or to promote the growth or metastasis of cancer cells. The alteration of cancer niches will impact the metabolism of both cancer and immune cells, modulating the survival and proliferation of cancer cells, and the activation and efficacy of immune cells. This review systematically describes the key characteristics of cancer cell metabolism and elucidates how such metabolic traits influence the metabolic behavior of immune cells. Moreover, this article also highlights the crucial role of immune cell metabolism in anti-tumor immune responses, particularly in priming T cell activation and function. By comprehensively exploring the metabolic crosstalk between cancer and immune cells in cancer niche, the aim is to discover novel strategies of cancer immunotherapy and provide effective guidance for clinical research in cancer treatment. In addition, the review also discusses current challenges such as the inadequacy of relevant diagnostic technologies and the issue of multidrug resistance, and proposes potential solutions including bolstering foundational cancer research, fostering technological innovation, and implementing precision medicine approaches. In-depth research into the metabolic effects of cancer niches can improve cancer treatment outcomes, prolong patients' survival period and enhance their quality of life.

New Insights into Aspirin's Anticancer Activity: The Predominant Role of Its Iron-Chelating Antioxidant Metabolites

Epidemiological studies have suggested that following long-term, low-dose daily aspirin (LTLDA) administration for more than 5 years at 75-100 mg/day, 20-30% of patients (50-80 years old) had a lower risk of developing colorectal cancer (CRC) and about the same proportion in developing iron deficiency anemia (IDA). In cases of IDA, an increase in iron excretion is suspected, which is caused by aspirin chelating metabolites (ACMs): salicylic acid, salicyluric acid, 2,5-dihydroxybenzoic acid, and 2,3-dihydroxybenzoic acid. The ACMs constitute 70% of the administered aspirin dose and have much longer half-lives than aspirin in blood and tissues. The mechanisms of cancer risk reduction in LTLDA users is likely due to the ACM's targeting of iron involved in free radical damage, iron-containing toxins, iron proteins, and associated metabolic pathways such as ferroptosis. The ACMs from non-absorbed aspirin (about 30%) may also mitigate the toxicity of heme and nitroso-heme and other iron toxins from food, which are responsible for the cause of colorectal cancer. The mode of action of aspirin as a chelating antioxidant pro-drug of the ACMs, with continuous presence in LTLDA users, increases the prospect for prophylaxis in cancer and other diseases. It is suggested that the anticancer effects of aspirin depend primarily on the iron-chelating antioxidant activity of the ACMs. The role of aspirin in cancer and other diseases is incomplete without considering its rapid biotransformation and the longer half-life of the ACMs.

Precision meets repurposing: Innovative approaches in human papillomavirus and Epstein-Barr virus-driven cancer therapy

Viral malignancies represent a distinct entity among cancers. Oncoviruses like the Human Papilloma Virus (HPV) and the Epstein Barr Virus (EBV) are highly potent inducers of oncogenic transformation leading to tumor development. HPV and EBV are known to be increasingly involved in the pathogenesis of various classes of cancers like cervical, head and neck, colorectal, breast, oral and anogenitial. Therapeutic vaccines directed at such oncoviruses, often fail to unleash the desired immune response against the tumor. This is largely due to the immunosuppressive microenvironment of the virus-induced tumors. Consequently, metronomic chemotherapies administered in conjunction with therapeutic viral vaccines have considerably enhanced the antitumor activity of these vaccines. Moreover, given the unique attributes of HPV and EBV-associated cancers, therapeutic agents directly targeting the oncoproteins of these viruses are still obscure. In this light, an increasing number of reports have evidenced the repurposing of drugs for therapeutic benefits in such cancers. This work delineates the significance and implications of metronomic chemotherapy and drug repurposing in HPV and EBV-associated cancers.

Peiminine Enhances Doxorubicin Cytotoxicity and Downregulates hsa-miR-106a-5p and hsa -miR-181a-5p in Human Gastric Adenocarcinoma Cells

Background

Gastric cancer (GC) is a prevalent and deadly cancer worldwide. Chemotherapy is the primary treatment, but some patients use herbal remedies, such as Peiminine from Fritillaria walujewii, for palliative care. Cancer cells can affect the expression of noncoding RNAs, like microRNA, which can then influence the expression of genes. This research aims to study the effects of Peiminine on Doxorubicin cytotoxicity and detect the expression levels of hsa-miR-106a-5p and hsa-miR-181a-5p in AGS human gastric adenocarcinoma cells.

Materials and Methods

AGS cells were cultured and treated with different concentrations of Peiminine. An MTT assay was performed to determine the concentration of Peiminine required to prohibit 50% cell growth (IC50) and the cell viability percentage of the AGS cell line. The percentage of AGS cell line apoptosis was determined using acridine orange (AO) and ethidium bromide (EtBr). Finally, molecular studies were conducted to compare hsa-miR-106a-5p and hsa-miR-181a-5p expression in the control and treated groups.

Results

According to the study, Peiminine has been found to enhance the cytotoxicity of Doxorubicin, which reduces cell viability and increases apoptosis in the AGS cell line. Furthermore, the study also indicates that the AGS cell line treated with Peiminine shows lower expression of hsa -miR-106a-5p and hsa -miR-181a-5p compared to the control group that was not treated.

Conclusion

Peiminine enhances Doxorubicin's effectiveness, inhibits AGS cell line growth, and reduces miRNA expression. Further research is needed for potential use as a supplementary GC treatment.