Anticancer Research Articles

The influence of polymorphism of genes associated with breast cancer on the effectiveness of drug antitumor therapy

Background. Increasing the survival rate of breast cancer patients is a problem all over the world and directly depends on the early detection of a malignant tumor. Genome-wide associative studies (GWAS) as a minimally invasive method may be used in determining risk of breast cancer or detection at an early stage. The increase in the number of patients with disseminated breast cancer in the Republic of Kazakhstan makes it necessary to search for molecular genetic markers of breast cancer for their use in the diagnosis and treatment of patients with this pathology.Aim. To retrospectively estimate the correlation of the effectiveness of drug antitumor therapy for breast cancer with gene polymorphism.Materials and methods. The study included the results of genotyping biomaterial samples on high-density DNA chips (venous blood of 1,277 Kazakh patients (in the third generation) with a verified diagnosis of breast cancer with locally advanced and disseminated breast cancer who received anticancer therapy), clinical data of patients, data on the clinical efficacy and toxicity of drug therapy. GWAS data (genotypes) associated with identified responses to chemotherapy drugs were compared with similar data recorded in international databases.Results. The family history study showed 16.52 % of women in the questionnaires had a family history of various types of ESR, and 86.25 % of them had a burden of breast cancer in women of the first degree of kinship. The average age of patients with breast cancer was 48.79 ± 11.44 years. According to the TNM classification, cancer in situ was detected in 4.78 % of patients, stage I of the disease was recorded in 15.27 %, stage II in 63.43 %, stage III in 12.60 %, stage IV in 3.92 % of patients. The vast majority of the patients (96.9 %) had a nodular form of breast cancer. The distribution of the patients by tumor phenotype: luminal type A was found in 20.4 % of patients, luminal type B in 38.3 %, luminal type B with HER2 overexpression in 14.3 %, HER2 positive form in 11.9 % of cases, 12.4 % of patients had an aggressive form – triple negative breast cancer. 18 main genotypes were identified in the Kazakh population as a result of the analysis of associations of the effectiveness of neoadjuvant chemotherapy (its individual components, according to chemotherapy regimens) and individual gene polymorphisms.Conclusion. An associative relationship between different types of gene polymorphism and the characteristics of response to various chemotherapeutic drugs used in the treatment of breast cancer has been confirmed. The obtained results formed the basis for the development of recommendations for making changes to the clinical practice of the Republic of Kazakhstan in order to use them in identifying a genetic predisposition to breast cancer and the effectiveness of drugs used in treatment.

Biochemical and molecular docking-based assessment of Spirulina platensis's bioactive constituents for their potential application as natural anticancer drug

Spirulina platensis and its extracts possess positive benefits for human health indications from malnutrition, antioxidant properties, and therapeutic properties. This study investigates the antioxidant activity of Spirulina platensis extracts and their cytotoxicity against the breast cancer cell line (MCF-7). The antioxidant and cytotoxicity properties of C- phycocyanin (C-PC) were directly compared with the diethyl ether extract of S. platensis (DEE). Results indicated that C-PC exhibited superior antioxidant activity compared to DEE extract. The observed values for C-PC are 1.453 μg/mL (IC50-value), 299.6 μM AA eq/mL, 86.68 μM TE eq/mL, and 179 μg/g for ABTS assay, DPPH, FRAP and total antioxidant activity, respectively. Moreover, C-PC also demonstrated enhanced cytotoxic activity against MCF-7 tumor cells with IC50 values of 100 μg/mL and 630 μg/mL for C-PC and DEE; respectively. C-PC treatment downregulated the expression of PI3K, Akt, mTOR, and Wnt. C-PC treatment to MCF-7 cells significantly induced caspase 3, caspase 8, and caspase 9. Similar effects, with lower tendency, were also observed for DEE extracts of S. platensis. Molecular docking studies suggest that S. platensis' bioactive constituents can induce apoptosis through intrinsic pathways. The current findings provide evidence for the medical importance of Spirulina platensis active constituents as promising natural anticancer drugs.

Hydrogen Bonding-Driven Self-Coacervation of Nonionic Homopolymers for Stimuli-Triggered Therapeutic Release.

Inspired by the unique functionalities of biomolecular membraneless organelles (MLOs) formed via liquid-liquid phase separation (LLPS) of intrinsically disordered proteins (IDPs) and nucleic acids, a great deal of effort has been devoted to devising phase-separated artificial subcellular dynamic compartments. These endeavors aim to unravel the molecular mechanism underlying the formation and intracellular delivery of susceptible macromolecular therapeutics. We report herein pyroglutamic acid (PGA)-based well-defined homopolymers featuring stimuli-tunable reversible self-coacervation ability. The polymer exhibits an upper critical solution temperature (UCST) transition in aqueous solutions and has the propensity to undergo cooling-induced LLPS, producing micrometer-sized liquid droplets. This phase separation phenomenon could be modulated by various factors, including polymer concentration, chain length, solution pH, and types and concentrations of different additives. These micrometer droplets are thermally reversible and encapsulate a wide variety of cargoes, including small hydrophobic fluorescent molecules, hydrophilic anticancer drugs, and fluorophore-labeled macromolecular proteins (bovine serum albumin and lysozyme). The payloads were released by exploiting the thermo/pH-mediated disassembly behavior of the coacervates, preserving the bioactivity of the sensitive therapeutics. This environmentally responsive, simple yet versatile artificial MLO model system will provide insights into the biomolecular nonionic condensates and pave the way for the de novo design of dynamic biomolecule depots.

Oxygen vacancy mediated photocatalysis of Ti3C2 MXene quantum dots/W18O49 hybrid membrane for peroxymonosulfate-enhanced oxidation degradation

Photocatalytic membrane technology shows great prospects in water decontamination. Coupling photocatalysis with peroxymonosulfate (PMS) can boost oxidation capacity by combining their superiorities sufficiently. Herein, 0D Ti3C2 MXene quantum dots (TMQDs) embedded oxygen vacancy-rich 3D sea urchin-like W18O49 microspheres (OTW) were synthesized via facile interface engineering combined with green plasma etching strategy. The visible-light driving flow-through membrane reactor was capable of degrading cyclophosphamide, a typical anticancer drug, and other common pollutants (5-fluorouracil, carbamazepine, bisphenol A, rhodamine B), with the removal and mineralization efficiencies of 10 μM pollutants reaching over 99 % and 63 %−79 % in 60 min with 0.5 mM PMS. Moreover, the long-term reliability of OTW membrane was validated through continuous treatment of 20 L sewage. Significantly, the newly designed photocatalytic membrane exhibited good tolerance to wide pH ranges, common coexisting substances in water, and various actual water matrix. The results of experimental and DFT theoretical calculations revealed that Schottky junction formed on the TMQDs/W18O49 interfaces and tunable O-defects could optimize electronic configuration, improve solar energy utilization, prevent photogenerated carriers’ recombination, promote H2O and PMS dissociation, making it possible that more •OH and SO4•− radicals participated in the oxidation degradation reaction. This study offers a design idea for preparing efficient and robust photocatalytic membrane via interface engineering and defect engineering strategies, which might contribute to bridging the translational gap between emerging photocatalytic techniques and practical environmental applications in near future.

Failure to progress: breast and prostate cancer cell lines in developing targeted therapies.

Developing anticancer drugs from preclinical to clinical takes approximately a decade in a cutting-edge biomedical lab and still 97% of most fail at clinical trials. Cell line usage is critical in expediting the advancement of anticancer therapies. Yet developing appropriate cell lines has been challenging and overcoming these obstacles whilst implementing a systematic approach of utilizing 3D models that recapitulate the tumour microenvironment is prudent. Using a robust and continuous supply of cell lines representing all ethnic groups from all locales is necessary to capture the evolving tumour landscape in culture. Next, the conversion of these models to systems on a chip that can by way of high throughput cytotoxic assays identify drug leads for clinical trials should fast-track drug development while markedly improving success rates. In this review, we describe the challenges that have hindered the progression of cell line models over seven decades and methods to overcome this. We outline the gaps in breast and prostate cancer cell line pathology and racial representation alongside their involvement in relevant drug development.

Design, synthesis, biological evaluation, and molecular modeling studies of new aminopyrimidine derivatives as potential anticancer agents

Design, synthesis, biological evaluation, and molecular modeling studies of new aminopyrimidine derivatives as potential anticancer agents

Exploring the Therapeutic Potential of Extracellular Vesicles Derived from Human Immature Dental Pulp Cells on Papillary Thyroid Cancer

Mesenchymal stem-cell-derived extracellular vesicles (MSC-EVs) have been increasingly investigated for cancer therapy and drug delivery, and they offer an advanced cell-free therapeutic option. However, their overall effects and efficacy depend on various factors, including the MSC source and cargo content. In this study, we isolated EVs from the conditioned medium of human immature dental pulp stem cells (hIDPSC-EVs) and investigated their effects on two papillary thyroid cancer (PTC) cell lines (BCPAP and TPC1). We observed efficient uptake of hIDPSC-EVs by both PTC cell lines, with a notable impact on gene regulation, particularly in the Wnt signaling pathway in BCPAP cells. However, no significant effects on cell proliferation were observed. Conversely, hIDPSC-EVs significantly reduced the invasive capacity of both PTC cell lines after 120 h of treatment. These in vitro findings suggest the therapeutic potential of hIDPSC-EVs in cancer management and emphasize the need for further research to develop novel and effective treatment strategies. Furthermore, the successful internalization of hIDPSC-EVs by PTC cell lines underscores their potential use as nanocarriers for anti-cancer agents.

Exploring the potential of tocopherols: mechanisms of action and perspectives in the prevention and treatment of breast cancer.

Currently, breast cancer is the most common cause of mortalitycaused by neoplasia in women worldwide. The unmet challenges of conventional cancer therapy are chemoresistance and lack of selectivity, which can lead to serious side effects in patients; therefore,new treatments based on natural compounds that serve as adjuvants in breast cancer therapyare urgently needed. Tocopherols are naturally occurring antioxidant compounds that have shown antitumor activity against several types of cancer, including breast cancer. This review summarizes the antitumoral activity of tocopherols, such as theantiproliferative, apoptotic, anti-invasive, and antioxidant effects of tocopherols, through different molecular mechanisms. According to the studies described, α-T, δ-T and γ-T are the most studied in breast tumor cells; however, α-T and γ-T show a more critical antitumor activity and significant potential as a complements to chemotherapeutic drugs against breast cancer, enhancing toxicity against tumor cells and preventing cytotoxicity in nontumor cells. However, the possible relationship between tocopherol intake, related to concentration,and the promotion of cancer in particular cases should not be ruled out, so additional studies are required to determine the correct dose to obtain the desired antitumor effect. Moreover, nanomicelles of D-α-tocopherol have promising potential as pharmaceutical excipients for drug delivery to improve the cytotoxicity and selectivity of first-line chemotherapeutics against breast cancer.

Poor therapeutic outcomes in KRAS-mutant non-small cell lung cancer due to chemoresistance conferred by SLC7A11.

This study aimed to confirm whether Kirsten rat sarcoma viral oncogene (KRAS) mutations affect the therapeutic efficacy of non-small cell lung cancer (NSCLC) and, if so, to explore what the possible mechanisms might be. We retrospectively analyzed the efficacy of immunochemotherapy in KRAS-mutant NSCLC patients compared to driver-negative patients. Online data platforms were used to find immunotherapy cases, and survival analysis compared treatments' efficacy. Cytotoxicity assays measured chemosensitivity in KRAS-mutant versus wild-type NSCLC to drugs like paclitaxel, carboplatin, and pemetrexed. Bioinformatics confirmed the KRAS-SLC7A11 link and cell experiments tested SLC7A11's role in chemoresistance. Animal studies verified the antitumor effects of SLC7A11 inhibitors with chemotherapy. Patients with KRAS-mutated NSCLC have a shorter therapeutic effectiveness duration with immunochemotherapy than patients with driver gene-negative status. The efficacy of immunotherapy alone is similar between the two groups. The KRAS mutation can enhance chemoresistance by upregulating SLC7A11, and inhibiting SLC7A11 can increase the sensitivity of KRAS-mutated NSCLC to chemotherapy. This study suggests that KRAS-mutant NSCLC can enhance its acquired chemoresistance by overexpressing SLC7A11, leading to poorer therapeutic outcomes. Targeting the KRAS-SLC7A11 axis could increase sensitivity to chemotherapeutic drugs, providing theoretical support for future treatment directions.

Evolution of Treatment Strategies for Gestational Trophoblastic Neoplasia: Chemotherapy, Immunotherapy, and Molecular Targeted Therapy.

In addressing Gestational Trophoblastic Neoplasia (GTN), it is imperative to acknowledge the evolving landscape of treatment options, especially in light of the challenges posed by traditional methods. While historically, surgical interventions, radiation therapy, and chemotherapeutic agents have been the mainstays, the emergence of resistance and high-risk scenarios necessitates a reevaluation of our therapeutic approaches. Our review highlights the promising advancements in immunotherapy and molecular targeted therapy as viable alternatives for GTN management. The introduction of immune checkpoint inhibitors and kinase inhibitors offers a paradigm shift, particularly for patients resistant to conventional chemotherapy regimens. These novel therapies not only exhibit efficacy but also demonstrate manageable toxicity profiles, particularly in high-risk cases. However, integrating these innovative treatments into established international guidelines presents a formidable task. As we move forward, it is imperative that future research not only prioritizes fertility preservation but also rigorously evaluates long-term toxicity implications. International collaboration becomes pivotal in addressing the nuances of this rare and complex disease. In conclusion, our review underscores the need for a nuanced approach to GTN treatment, one that prioritizes reduced toxicity and improved quality of life. By embracing the advancements in immunotherapy and molecular targeted therapy, we can pave the way for more effective and patient-centered care in the management of GTN.

Oral Neuropathy Associated with Commonly used Chemotherapeutic Agents: A Narrative Review.

Chemotherapy-induced peripheral neuropathy (CIPN) is a frequent complication of cytotoxic chemotherapeutic agents; its incidence largely varies, depending on type, dose, agent and preexisting risk factors. Oral-and-perioral-CIPN (OCIPN) is underreported. Neurotoxic agents can cause jaw pain or numbness. This review aims to present available data on OCIPN RECENT FINDINGS: A narrative literature review, following SANRA guidelines was conducted. PubMed and Cochrane databases were searched until September 2023. Articles referring to neuropathy or neuropathic pain due to head and neck cancer, head and neck radiotherapy, oropharyngeal mucositis, infection or post-surgical pain were excluded. Platinum-based chemotherapeutics, taxanes, vinca alkaloids, immunomodulatory and alkylating agents can cause OCIPN. Platinum-based chemotherapeutics can cause orofacial cold sensitivity, orofacial and jaw pain, oral cavity tingling and teeth hypersensitivity. Taxanes may induce oral cavity and tongue numbness and tingling as well as hot hypersensitivity. Vinca alkaloids may cause jaw, teeth and lips pain and oral mucosa hyperalgesia. Immunomodulatory drugs can cause lips, tongue and perioral numbness, while alkylating agents induce tongue and lips tingling and teeth cold-hypersensitivity. Chemotherapy may cause OCIPN due to changes in cellular structure and function, like alterations in membrane receptors and neurotransmission. OCIPN should be documented and physicians, dentists and health care providers should be alerted.

Adsorption of Dacarbazine as Anticancer Drug on Si60, C60, B30N30, Sc-Si60, Sc-C60, Sc-B30N30 Nanocages

Adsorption of Dacarbazine as Anticancer Drug on Si60, C60, B30N30, Sc-Si60, Sc-C60, Sc-B30N30 Nanocages

Co-delivery of Bcl-2 siRNA and doxorubicin using liposome-incorporated poly(ε-caprolactone) /chitosan nanofibers for the treatment of lung cancer

The small interfering RNA (siRNA) and chemotherapeutic drugs-incorporated liposome-nanofiber hybrid delivery system could inhibit tumor growth and decrease the adverse side effects. In the present study, doxorubicin (DOX) anticancer drug and Bcl-2 siRNA have been incorporated into the liposome-embedded chitosan-poly (ethylene oxide)/poly (ε-caprolactone) (CS/PEO/PCL) pH-sensitive nanofibrous hybrid formulation for treating lung cancer. The mean particle size & zeta potential of liposome, DOX-liposome, and DOX-Bcl-2-liposome were 130 ± 10 nm & 27.85 ± 1.65 mV, 155 ± 15 nm & 26.30 ± 1.3 mV, and 195 ± 30 nm &11.31 ± 0.65 mV, respectively. The average diameter of electrospun CS/PEO/PCL/DOX-siRNA-liposome simple and CS/PEO/PCL/DOX-siRNA-liposome core-shell nanofibers was 385 ± 80, and 485 ± 100 nm, respectively. The extended release of DOX and si-RNA (30 days) were achieved from DOX-Bcl-2-liposome-incorporated CS/PEO/PCL core-shell nanofibers. The maximum down-regulation of Bcl-2 siRNA, apoptosis of cancer cells, and reduction in the cell viability of A549 lung carcinoma cells were achieved using DOX-Bcl-2 liposome-incorporated CS/PEO/PCL core-shell nanofibers. The in vivo results indicated the maximum suppress of tumor growth without change in the body weight for the mice treated with DOX-Bcl-2 liposome-incorporated CS/PEO/PCL nanofibers. The obtained results demonstrated that the prepared hybrid delivery system presented a novel effective formulation for treating lung cancer.

De novo assembly and comprehensive analysis of the mitochondrial genome of Taxus wallichiana reveals different repeats mediate recombination to generate multiple conformations

Taxus plants are the exclusive source of paclitaxel, an anticancer drug with significant medicinal and economic value. Interspecies hybridization and gene introgression during evolution have obscured distinctions among Taxus species, complicating their phylogenetic classification. While the chloroplast genome of Taxus wallichiana, a widely distributed species in China, has been sequenced, its mitochondrial genome (mitogenome) remains uncharacterized.We sequenced and assembled the T. wallichiana mitogenome using BGI short reads and Nanopore long reads, facilitating comparisons with other gymnosperm mitogenomes. The T. wallichiana mitogenome spanning 469,949 bp, predominantly forms a circular configuration with a GC content of 50.51%, supplemented by 3 minor configurations mediated by one pair of LRs and two pairs of IntRs. It includes 32 protein-coding genes, 7 tRNA genes, and 3 rRNA genes, several of which exist in multiple copies.We detailed the mitogenome's structure, codon usage, RNA editing, and sequence migration between organelles, constructing a phylogenetic tree to elucidate evolutionary relationships. Unlike typical gymnosperm mitochondria, T. wallichiana shows no evidence of mitochondrial-plastid DNA transfer (MTPT), highlighting its unique genomic architecture. Synteny analysis indicated extensive genomic rearrangements in T. wallichiana, likely driven by recombination among abundant repetitive sequences. This study offers a high-quality T. wallichiana mitogenome, enhancing our understanding of gymnosperm mitochondrial evolution and supporting further cultivation and utilization of Taxus species.

A quantum mechanistic investigation into the unusual reactions of nitrilimine and nitrile oxide with 2,3,4,5-tetraphenylcyclopentadienone.

The theoretical study investigates the [3 + 2] cycloaddition (32CA) reactions between C, N-diphenyl nitrilimine with 2,3,4,5-tetraphenylcyclopentadienone and benzonitrile oxide with 2,3,4,5-tetraphenylcyclopentadienone. Nitrilimines and nitrile oxides are dipoles used in the synthesis of several heterocyclic compounds, including spiropyrazoline oxindoles and isoxazolines. The derivatives of these compounds are found with different biological activities, such as ion channel blockers, anti-inflammatory and anticancer agents as well as antimalarial. Conceptual density functional theory (CDFT) analysis, along with the activation energies of the 32CA reaction between C, N-diphenyl nitrilimine with 2,3,4,5-tetraphenylcyclopentadienone, demonstrates concordance with the empirical findings. The 32CA reaction is found to proceed through a very polar single-step asynchronous mechanism. While deductions from the activation energies of the 32CA reaction between benzonitrile oxide and 2,3,4,5-tetraphenylcyclopentadienone are found to lead to the experimental product, the parr function analysis could not explain the observed chemo- and regioselectivity. This 32CA reaction is also found to proceed through a one-step asynchronous mechanism, though with a non-polar character. The modulation of substituents positioned at the reactive sites of the reactants is found to influence the kinetics, thermodynamics, and CDFT parameters of the two 32CA reactions, consequently impacting the observed selectivities. The 32CA reactions between C, N-diphenyl nitrilimine with 2,3,4,5-tetraphenylcyclopentadienone and benzonitrile oxide with 2,3,4,5-tetraphenylcyclopentadienone have been explored theoretically using the density functional theory method at the hybrid ωB97X-D coupled with the split valence triple-ξ (TZ) basis set as implemented in the Gaussian 09. Solvent effects were taken into account by full optimization of the gas phase geometries through the polarizable continuum model developed within the self-consistent reaction field.

Metal-Organic Framework: Fabrication of Nano Fluorescent Composite Materials and Treatment of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is a common malignant tumor originating from liver cells, characterized by complex pathogenesis and limited treatment options such as surgery, chemotherapy, and transplantation. Cisplatin, an effective chemotherapeutic agent, disrupts cancer cell DNA but is hindered by side effects and the need for controlled sustained release to optimize efficacy. Metal-organic frameworks (MOFs) have emerged as promising nanocarriers for precise local drug delivery, reducing required doses and mitigating side effects of chemotherapeutic drugs, thus offering a potential avenue for hepatocellular carcinoma (HCC) treatment. In this research, a rectangular channel MOF (Rumgay H, Ferlay J, Martel C, Georges D, Ibrahim AS, Zheng R, Wei W, Lemmens VEPP, Soerjomataram I (2022) Global, regional and national burden of primary liver cancer by subtype. Eur J Cancer 161:108-118) carrier was synthesized using ligand L as the organic linker coordinated with Cu(II) and I(I). The MOF's structure and fluorescence properties were characterized. Additionally, to enhance substrate biocompatibility, composite carrier materials were prepared by incorporating polylactic acid (PLA) with 1, utilized for cisplatin loading. To evaluate the inhibitory effect of PLA-1@cisplatin on HCC, HepG-2 and Huh-7 HCC cell lines were treated with varying concentrations of the drug for 48h, and their cell viability was assessed. The results demonstrated a significant dose-dependent reduction in cell viability of both HepG-2 and Huh-7 cells. To explore the potential inhibitory mechanism of PLA-1@cisplatin on HCC, the mRNA levels of GADD45A and NACC1 in HepG-2 and Huh-7 cells post-treatment were measured. GADD45A expression, initially low in HCC cells, was significantly upregulated after drug treatment, while NACC1, typically highly expressed in HCC, showed a significant decrease in mRNA levels with increasing concentrations of PLA-1@cisplatin. These findings indicate that PLA-1@cisplatin effectively upregulates GADD45A expression and downregulates NACC1 expression. Overall, the developed cisplatin-loaded nanoparticle system holds promise for HCC treatment by reducing chemotherapy side effects and enhancing drug efficacy.

Promotion of tumor angiogenesis and growth induced by low-dose antineoplastic agents via bone-marrow-derived cells in tumor tissues

Promotion of tumor angiogenesis and growth induced by low-dose antineoplastic agents via bone-marrow-derived cells in tumor tissues

Malignancy progression and treatment efficacy estimation of osteosarcoma patients based on in vitro cell culture model and analysis

BackgroundOsteosarcoma (OS) usually happens in patients under 20 years old and is notorious for its low survivorship and limb loss. Personalized medicine is a viable approach to increase the efficiency of chemotherapy which is the main prognostic factor for survivorship after surgical treatment. MethodsIn this five-year prospective observational study, we collected primary cells of osteosarcoma from 15 patients, and examined the correlation between clinical characters of patients and cell properties characterized using various in vitro assays. The properties including genes expression, pro-angiogenic capability and anti-cancer drug response are characterized respectively by using RT-PCR, tube formation assay, osteogenesis assay and drug testing on 3D tumor spheroid model. ResultThe results suggest that OS patients with higher MMP9 expression levels have higher probability to develop skip metastasis (p = 0.041). The 3D tumor spheroid test based on the median lethal dose from 2D culture provides some prognostic value. Patients do not response well to methotrexate (MTX) show higher percentage of high pathology grade (p = 0.009) and lung metastasis (p = 0.044). Also, patients respond well to ifosfamide (IFO) have higher probability to achieve high tumor necrosis rate (p = 0.007). ConclusionThe association between cell properties and clinical characters of patients provided by our data can act as potential prognostic factors to help physicians to develop effective personalized chemotherapy for osteosarcoma treatments.

Enhancement of chemoresistance by claudin-1-mediated formation of amino acid barriers in human lung adenocarcinoma A549 cells

Claudin-1 (CLDN1) is highly expressed in human lung adenocarcinoma-derived A549 cells and is involved in the augmentation of chemoresistance. However, the mechanism of chemoresistance is not fully understood. In the tumor microenvironment, cancer cells are exposed to stress conditions such as hypoxia and malnutrition. Here, we investigated the effect of CLDN1 expression on amino acid (AA) flux and chemoresistance using A549 cells. The expression of L-type AA transporters, LAT1 and LAT3, was decreased by CLDN1 silencing in A549 spheroids. A reduction in extracellular AA concentration increased the expression of these AA transporters in two-dimensional (2D) cultured cells. The paracellular AA flux except for Ser, Thr, Tyr, Ala, and Gly was enhanced by CLDN1 silencing. These results suggest that CLDN1 forms a paracellular barrier to some AAs, leading to the elevation of LAT1/3 expression in spheroids. The production of reactive oxygen species in the mitochondria and cytosol was decreased by CLDN1 silencing in spheroids, resulting in downregulation of the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and its target antioxidant genes. CLDN1 silencing enhanced the cytotoxicity of anticancer drugs including doxorubicin and cisplatin, which was blocked by sulforaphane, an inducer of Nrf2 signaling. Similarly, the anticancer-induced toxicity was enhanced by Nrf2 silencing. In 2D cultured cells, the anticancer-induced toxicity was attenuated by AA deficiency and sulforaphane. We suggest that CLDN1 forms an AA barrier in spheroids, leading to the augmentation of Nrf2-dependent chemoresistance in A549 cells.

Aptamer-functionalized triptolide with release controllability as a promising targeted therapy against triple-negative breast cancer

Targeted delivery and precise release of toxins is a prospective strategy for the treatment of triple-negative breast cancer (TNBC), yet the flexibility to incorporate both properties simultaneously remains tremendously challenging in the X-drug conjugate fields. As critical components in conjugates, linkers could flourish in achieving optimal functionalities. Here, we pioneered a pH-hypersensitive tumor-targeting aptamer AS1411-triptolide conjugate (AS-TP) to achieve smart release of the toxin and targeted therapy against TNBC. The multifunctional acetal ester linker in the AS-TP site-specifically blocked triptolide toxicity, quantitatively sustained aptamer targeting, and ensured the circulating stability. Furthermore, the aptamer modification endowed triptolide with favorable water solubility and bioavailability and facilitated endocytosis of conjugated triptolide by TNBC cells in a nucleolin-dependent manner. The integrated superiorities of AS-TP promoted the preferential intra-tumor triptolide accumulation in xenografted TNBC mice and triggered the in-situ triptolide release in the weakly acidic tumor microenvironment, manifesting striking anti-TNBC efficacy and virtually eliminated toxic effects beyond clinical drugs. This study illustrated the therapeutic potential of AS-TP against TNBC and proposed a promising concept for the development of nucleic acid-based targeted anticancer drugs.