Resistance Of Tumor Cells Research Articles

Photothermally Reinforced Nanozyme Remodeling Tumor Microenvironment of Redox and Metabolic Homeostasis to Enhance Ferroptosis in Tumor Therapy.

The acidity and high GSH level in the tumor microenvironment (TME) greatly limit the antitumor activity of nanozymes. Thus, enhancing nanozymes' activity is fundamentally challenging in tumor therapy. Although the combination of photothermal therapy (PTT) and nanozymes can enhance the catalytic activity, cancer cells will overexpress heat shock proteins (HSPs) at high temperature, aggravating the heat resistance of tumor cells, which in turn compromises the outcome of chemodynamic therapy. Herein, we propose an iron-doped metal-organic framework nanozyme (IB@Fe-ZIF8@PDFA) that can be activated under the weak acidity and high level of GSH, demonstrating the activities of GSH oxidation (GSH-OXD), peroxidase (POD), and NADH oxidase (NADH-OXD). Under laser irradiation, it displays photothermal-enhanced multienzyme activities to simultaneously eliminate tumors and inhibit tumor metastasis. While consuming endogenous GSH, IB@Fe-ZIF8@PDFA promotes the decomposition of H2O2 into ·OH, enhancing ferroptosis in tumor cells. Surprisingly, IB@Fe-ZIF8@PDFA nanozyme can oxide NADH and subsequently limit the ATP supply, reducing the expression of HSPs and significantly weakening the heat resistance of tumor cells during PTT. Meanwhile, H2O2 is generated during this procedure, which can endogenously replenish the consumed H2O2. Thus, this IB@Fe-ZIF8@PDFA nanozyme constitutes a self-cascading platform to consume GSH and NADH, endogenously replenish the H2O2 and continuously generate ·OH to facilitate ferroptosis by disrupting the redox and metabolic homeostasis in tumor cells, achieving tumor elimination and tumor metastasis inhibition.

Synergistic Chemo-Immunotherapy Using pH-Responsive Nanoparticles in Breast Cancer Treatment: In Vitro and In Vivo Studies.

Recent research underscores the pivotal role of the heterogeneous multicellular interactome within the tumor microenvironment (TME) in tumor progression and survival. Tumor-associated macrophages (TAMs), among other nonmalignant cells in the TME, promote an immunosuppressive environment, fostering tumor cell survival, proliferation, and resistance. Hence, combining chemotherapy with immunomodulatory agents to transition TAMs to an immunostimulatory phenotype holds immense therapeutic potential. The present study focuses on developing tumor-responsive nanoparticles (NPs) for combined chemo-immunotherapy using resiquimod (RSQ), a TLR 7/8 agonist as an immunomodulator, and paclitaxel (PTX) as chemotherapeutics. A pH-responsive NP known as PHNP, tailored with a star-shaped PLGA conjugated with poly histidine, was engineered to selectively deliver a consistent ratio of PTX and RSQ directly to the tumor site. In vitro studies demonstrate enhanced drug release at pH 6.4, increased penetration in tumor spheroids, and increased cytotoxic efficacy against breast cancer cells. Furthermore, PHNPs activate macrophages for antitumor activity. In vivo studies demonstrated a notable rise in plasma AUC and improved delivery of drugs to the tumor using PHNPs, resulting in enhanced effectiveness against tumor growth in a mouse orthotopic breast cancer model. Notably, PHNP treatment elevated intratumoral ROS and apoptosis levels and inhibited lung metastasis. Overall, this study underscores the potential of the PTX and RSQ combination as a prospective combined chemo-immunotherapeutic modality.

Heterogeneous nuclear ribonucleoprotein K is a potential target for enhancing the chemosensitivity of nasopharyngeal carcinoma.

The resistance of tumor cells to chemotherapy drugs is a critical determinant in the recurrence and metastasis of nasopharyngeal carcinoma (NPC). Therefore, it is crucial to identify effective biotargets that can enhance the sensitivity of NPC cells to chemotherapy drugs. Heterogeneous nuclear ribonucleoprotein K (hnRNPK) plays a central role in regulating chemotherapy resistance across various tumor types. However, its specific function in NPC cells remains unclear. This study reveals that hnRNPK is overexpressed in NPC tissues while weakly expressed in normal nasopharyngeal tissues. The expression level of hnRNPK is negatively associated with NPC patient survival. Importantly, hnRNPK is a key inducer of chemotherapy resistance in NPC, as evidenced by the significant increase in NPC cell sensitivity to cisplatin following hnRNPK knockdown. Mechanistically, hnRNPK induces chemotherapy resistance in NPC cells by suppressing the activation of the Akt/caspase 3 pathway. In NPC tumor-bearing mice, hnRNPK knockdown enhances the efficacy of cisplatin chemotherapy. Consequently, this work identifies a potential target for enhancing the sensitivity of NPC cells to chemotherapy.

Multifunctional role of the tumor associated monocytes/macrophages in the metastatic potential of inflammatory breast cancer.

Inflammatory breast cancer (IBC) is the most aggressive and lethal phenotype form of breast cancer, which afflicts young women at high incidence in North Africa compared to other continents of the world. IBC is characterized by highly metastatic behavior and possesses specific pathobiological properties different from non-IBC. IBC disease displays unusual common properties at typical presentation, including positive metastatic lymph-nodes, high infiltration of tumor associated monocytes/macrophages, rapid progression to distant metastasis, and possibly the production of a unique repertoire of growth factors, cytokines and chemokines, as well as a striking association with different polarized macrophages compared to non-IBC. Indeed, tumor associated monocytes/macrophages (TAM/M) play a crucial role in breast cancer development. Previously, we showed that cross talk between IBC cells and patient derived TAMs occurs via secretion of inflammatory mediators from TAMs that act on specific extracellular domain receptors activating down-stream signaling pathways that promote the epithelial-to-mesenchymal transition, cancer cell invasion, IBC stem cell properties, drug resistance, local and metastatic recurrence of residual tumor cells and other key markers of malignancy, including in vitro colony formation capacity. In this mini review, we will discuss the role of TAMs in IBC cancer metastatic potential and molecules involved. The review also discusses the recent discoveries in the field of IBC research.

MMP-2 Responsive Gold Nanorods Loaded with HSP-70 siRNA for Enhanced Photothermal Tumor Therapy.

Gold nanorods (Au NRs) are a valuable photothermal nanomaterial for tumor therapy. However, when treated with Au NRs for photothermal therapy, the expression of heat shock proteins in tumors will increase, which will induce heat resistance in tumor cells and reduce the photothermal therapeutic effect of Au NRs. By RNA interference, the expression of heat shock proteins would be effectively inhibited to improve the efficasy of tumor photothermal therapy. However, deep and noninvasive tissue penetration remains a great obstacle to applying siRNA successfully. Thus, the nanoplatform AGC/HSP-70 siRNA was designed for enhanced photothermal tumor therapy by RNA interference. In the AGC/HSP-70 siRNA complex, the Au-S bond modified the matrix metalloproteinase-2 (MMP-2)-sensitive peptide GPLGLAG on the surface of gold nanorods. Moreover, the natural basic polysaccharide (chitosan) was reacted with the peptide by an amide bond for delivering heat shock protein 70 silencing siRNA (HSP-70 siRNA). Modifying the MMP-2-sensitive linker could cause more Au NRs to accumulate in tumors to exert a photothermal effect and promote the penetration of HSP-70 siRNA and chitosan complexes into deep tumor tissues. In vitro experiments indicated that the enzymolysis of the MMP-2-sensitive linker for AGC/HSP-70 siRNA could promote the cellular uptake and perinuclear distribution of HSP-70 siRNA in tumor cells, which may be due to the smaller size and positive electricity of the complexes. All of these results ensured the efficient gene silencing effect of HSP-70 siRNA to enhance the photothermal therapeutic effect of Au NRs in tumor tissues, as demonstrated by the gene silencing and cellular apoptotic experiments. In vivo experiments further proved that the AGC/HSP-70 siRNA nanoplatform efficiently improved the photothermal effect of Au NRs. In summary, this work proved that AGC/HSP-70 siRNA is a promising drug delivery strategy for enhancing the photothermal therapy of tumors by regulating the photothermal sensitivity of deep tumor cells as well as retaining more Au NRs in tumor tissues, and also provides a novel strategy for tumor photothermal therapy.

Recent advances in organelle-specific autophagy in melanoma

Abstract Organelle-specific autophagy, the selective degradation of distinct cellular organelles, plays a pivotal role in the pathogenesis and progression of various diseases, including melanoma. This review provides a comprehensive analysis of recent advances in organelle-specific autophagy in melanoma, focusing on key processes such as mitophagy, reticulophagy, lysophagy, nucleophagy, pexophagy, and ribophagy. Emerging evidence highlights the roles these autophagic pathways play in melanoma development, with each process contributing uniquely to tumor cell proliferation, migration, invasion, and resistance to therapy. Mitophagy, for example, can both support tumor growth by enhancing mitochondrial quality and suppress it by inducing cell death. Similarly, ER stress exhibits a dual regulatory role, promoting either drug resistance or apoptosis depending on the context, with reticulophagy playing a critical role in modulating these effects. These findings emphasize the importance of further exploring organelle-specific autophagy as both a potential therapeutic target and a prognostic biomarker in melanoma. This research holds significant promise for the development of novel clinical strategies aimed at improving patient outcomes.

Development of drug resistance in cancer cells

Abstract Introduction/Objective The purpose of this study was to evaluate omeprazole treament in cancer cells. Methods/Case Report The colorectal cancer cell line, CACO2, was treated with omeprazole at two different concentrations and methotrexate as a positive control for 3-4 months. Using exon-spanning primers for the ABCG2 and ABCB1 genes, qPCR was used to monitor changes in mRNA expression of the efflux pumps, Breast Cancer Resistant Protein (BCRP) and P-glycoprotein (Pgp). Upregulation of BCRP and Pgp was observed through the western blot assay. Once overexpression of BCRP was confirmed, the omeprazole-treated and methotrexate-treated cells were tested for chemotherapy-resistance using the Prestoblue proliferation assay and were compared to the untreated cells. The omeprazole treatments were repeated for reproducibility using two esophageal cancer cell lines. The treated cells were also studied for expression changes of possible drug resistant and cancer genes using RNASeq analysis. Results (if a Case Study enter NA) N/A Conclusion Esophageal cancer patients, who are treated for acid reflux, may be at higher risk for developing chemotherapy-resistant/multidrug resistance (MDR) tumor cells prior to chemotherapy treatment. Esophageal cancer patients with MDR tumors will have lower chance of survival compared to patients who are responsive to chemotherapy treatment. By identifying the overexpression of BCRP in the tumor cells of cancer, oncologists will be able to use a better treatment plan with more effective chemotherapy drugs.

Novel ultrathin ferrous sulfide nanosheets: Towards replacing black phosphorus in anticancer nanotheranostics

Biodegradable two-dimensional nanomaterials could be a significant breakthrough in the field of oncology nanotheranostic agents, which are rapidly emerging as promising candidates for tumor theranostic applications. Herein, a novel biodegradable ferrous sulfide nanosheet (FeS NS) is developed. Compared to the traditional photothermal material, black phosphorus nanosheet (BP NS), FeS demonstrates superior degradability and enhanced photothermal performance, and making it ideal for efficient photothermal therapy (PTT) of tumors. In the acidic tumor microenvironment, FeS degrades and releases H2S, which inhibits mitochondrial respiration and ATP production. This process leads to a reduction in heat shock protein expression, lowering the resistance of tumor cells to photothermal stimulation, and improving the efficacy of PTT. The released Fe2+ exhibits efficient peroxidase activity, triggering ferroptosis in tumor cells. Furthermore, due to its superparamagnetic nature, FeS NSs could accumulate at the tumor site and provide a strong magnetic resonance imaging (MRI) signal for imaging-guided tumor therapy. Overall, as a promising alternative to BP, the FeS NSs are a potentially innovative nanotheranostic agent of tumors, offering a synergistic approach to ferroptosis−PTT with MRI guidance.

Vesicle-Transported Multidrug Resistance as a Possible Therapeutic Target of Natural Compounds.

A key role of extracellular vesicles (EVs) is mediating both cell-cell and cell-stroma communication in pathological/physiological conditions. EVs from resistant tumor cells can transport different molecules like P-glycoprotein (P-gp), acting as a shuttle between donor and recipient cells, resulting in a phenotypic change. The aim of our work was to isolate, characterize, and inhibit the release of EVs in two multidrug resistance (MDR) cancer models: MCF-7R (breast cancer cell line) and HL-60R (acute myeloid leukemia cell line). The existence of P-gp in EVs from MDR cells was confirmed by Western blotting assays. The characterization of EVs was carried out by evaluating the size using NTA and the presence of specific markers such as CD63, Hsp70 and Syntenin. The ability of HL-60R and MCF-7R to perform horizontal transfer of P-gp via EVs to sensitive cells was assessed using three different methods. The acquisition of resistance and its inhibition in recipient cells was confirmed by MTS 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Our data showed that cell lines (MDR) release P-gp-loaded EVs, unlike sensitive cells. The acquisition of resistance determined by the incorporation of P-gp into the membrane of sensitive cells was confirmed by the reduced cytotoxic activity of doxorubicin. Natural compounds such as curcumin, lupeol, and heptacosane can block vesicular transfer and restore the sensitivity of HL-60 and MCF-7 cells. Our study demonstrates that natural inhibitors able to reverse this mechanism may represent a new therapeutic strategy to limit the propagation of the resistant phenotype.

CASPER: A Phase I trial combining calaspargase pegol-mnkl and cobimetinib in pancreatic cancer.

Asparagine synthetase (ASNS) catalyzes the biosynthesis of asparagine from aspartate and glutamine. Cells lacking ASNS, however, are auxotrophic for asparagine. Use of L-asparaginase to promote asparagine starvation in solid tumors with low ASNS levels, such as pancreatic ductal adenocarcinoma (PDAC), is a rationale treatment strategy. However, tumor cell resistance to L-asparaginase has limited its clinical utility. Our preclinical studies show that RAS/MAPK signaling circumvents L-asparaginase-induced tumor killing, but L-asparaginase and MEK inhibition potentiated tumor killing; suggesting that this combination may provide meaningful clinical benefit to patients with PDAC. This Phase I trial (NCT05034627) will evaluate the safety and tolerability of the MEK inhibitor, cobimetinib, in combination with pegylated L-asparaginase, L calaspargase pegol-mknl, in patients with locally-advanced or metastatic PDAC.

The immunomodulatory effects of vitamins in cancer.

Nutrition may affect animal health due to the strong link between them. Also, diets improve the healing process in various disease states. Cancer is a disease, where the harmful consequences of tumors severely impair the body. The information regarding the evolution of this disease is extrapolated from human to animal because there are few specific studies regarding nutritional needs in animals with cancer. Thus, this paper aims to review the literature regarding the immunomodulatory effects of vitamins in mammal cancer. An adequate understanding of the metabolism and requirements of nutrients for mammals is essential to ensuring their optimal growth, development, and health, regardless of their food sources. According to these: 1) Some species are highly dependent on vitamin D from food, so special attention must be paid to this aspect. Calcitriol/VDR signaling can activate pro-apoptotic proteins and suppress anti-apoptotic ones. 2) Nitric oxide (NO) production is modulated by vitamin E through inhibiting transcription nuclear factor kappa B (NF-κB) activation. 3) Thiamine supplementation could be responsible for the stimulation of tumor cell proliferation, survival, and resistance to chemotherapy. 4) Also, it was found that the treatment with NO-Cbl in dogs is a viable anti-cancer therapy that capitalizes on the tumor-specific properties of the vitamin B12 receptor. Therefore, diets should contain the appropriate class of compounds in adequate proportions. Also, the limitations of this paper are that some vitamins are intensively studied and at the same time regarding others, there is a lack of information, especially in animals. Therefore, some subsections are longer and more heavily debated than others.

7559 TRIM21 Regulates Activation of ERK1/2 to Promote Growth and Drug Resistance in Pituitary Neuroendocrine Tumors

Abstract Disclosure: Y. Liu: None. F. Liu: None. C. Li: None. T. Zhang: None. L. Xue: None. Z. Wu: None. Objective: To investigate the role of the TRIM family genes in pituitary neuroendocrine tumors (PitNETs) and provide new targets and strategies for the clinical treatment of these tumors. Methods: A CRISPR screening system targeting the TRIM family was constructed and validated using next-generation sequencing. Stable cell lines overexpressing or knocking out TRIM21 were generated, and functional validation was performed using assays such as CCK-8, colony formation, and xenograft tumor growth in nude mice. RNA-seq, mass spectrometry, immunohistochemistry, and immunoblotting were employed to explore the signaling pathways and mechanisms underlying TRIM21's actions. Immunoprecipitation, immunofluorescence, GST-pulldown, NanoBiT assays, and ubiquitination experiments were conducted to investigate the effects of TRIM21 on ERK1/2. Immunohistochemistry and immunoblotting were used to explore the role of TRIM21 in drug- resistant prolactinomas and the correlation between TRIM21 and p-ERK. Results: Through screening the proliferative and drug-resistant effects of the TRIM family in MMQ and GH3 cells, we found that knocking out TRIM21 may inhibit cell growth and enhance drug sensitivity. Subsequently, stable cell lines overexpressing or knocking out TRIM21 were generated in MMQ and GH3 cells, revealing that TRIM21 overexpression promotes pituitary tumor cell growth and resistance to drug treatment, while TRIM21 knockout inhibits cell growth and enhances drug sensitivity. Cell-derived xenograft models showed that TRIM21 overexpression promoted growth of GH3 cells in vivo and resistance to cabergoline (CAB), while TRIM21 knockout suppressed growth of MMQ cells in vivo. Further exploration of the signaling pathways influenced by TRIM21 revealed that TRIM21 knockout downregulates the MAPK signaling pathway, while TRIM21 overexpression upregulates it. TRIM21 overexpression upregulates p-ERK1/2 in the MAPK pathway, while TRIM21 knockout decreases p-ERK. However, there is no significant influence on ERK1/2, JNK, p-JNK, p38, or p-p38. Mechanically, TRIM21 interacted with ERK1/2, enhancing the K27-linked ubiquitination of ERK1/2 and promoting their interaction with MEK1/2. In addition, the TRIM21 with D-docking mutant or ERK1/2 with CD-domain mutant resulted in the loss of their interaction. Furthermore, TRIM21 and p-ERK levels were significantly elevated in drug-resistant prolactinomas and immunohistochemical semi-quantitative analysis demonstrated a positive correlation between TRIM21 and p-ERK. Conclusion: The ubiquitin ligase TRIM21 catalyzes K27-linked ubiquitination of ERK1/2, enhancing its interaction with MEK1/2 and activation, thereby promoting growth and drug resistance in pituitary neuroendocrine tumors. TRIM21 may serve as a potential target for the treatment of pituitary neuroendocrine tumors. Presentation: 6/3/2024

Steroidal saponins: Natural compounds with the potential to reverse tumor drug resistance (Review).

Steroidal saponins are a type of natural product that have been widely used in Chinese herbal medicine, with a variety of pharmacological activities, such as antitumor, anti-inflammatory and anti-bacterial effects. Cancer has become a growing global health problem, and drug therapy is currently the most important clinical antitumor treatment. However, drug resistance is a major obstacle to the effectiveness of chemotherapy, resulting in >90% of deaths of patients with cancer receiving conventional chemotherapy. It has been found that steroidal saponins may exert an effect on the reversal of drug resistance in tumor cells by regulating apoptosis, autophagy, epithelial-mesenchymal transition and drug efflux through multiple related signaling pathways. The present study reviews the role and mechanism of steroidal saponins in the treatment of tumor drug resistance, aiming to provide a scientific basis and research ideas for the future development and clinical application of natural steroidal saponins.

Programmed Cascade Polydopamine Nanoclusters for Pyroptosis-Based Tumor Immunotherapy.

Pyroptosis, an inflammatory cell death, plays a pivotal role in activating inflammatory response, reversing immunosuppression and enhancing anti-tumor immunity. However, challenges remain regarding how to induce pyroptosis efficiently and precisely in tumor cells to amplify anti-tumor immunotherapy. Herein, a pH-responsive polydopamine (PDA) nanocluster, perfluorocarbon (PFC)@octo-arginine (R8)-1-Hexadecylamine (He)-porphyrin (Por)@PDA-gambogic acid (GA)-cRGD (R-P@PDA-GC), is rationally design to augment phototherapy-induced pyroptosis and boost anti-tumor immunity through a two-input programmed cascade therapy. Briefly, oxygen doner PFC is encapsulated within R8 linked photosensitizer Por and He micelles as the core, followed by incorporation of GA and cRGD peptides modified PDA shell, yielding the ultimate R-P@PDA-GC nanoplatforms (NPs). The pH-responsive NPs effectively alleviate hypoxia by delivering oxygen via PFC and mitigate heat resistance in tumor cells through GA. Upon two-input programmed irradiation, R-P@PDA-GC NPs significantly enhance reactive oxygen species production within tumor cells, triggering pyroptosis via the Caspase-1/GSDMD pathway and releasing numerous inflammatory factors into the TME. This leads to the maturation of dendritic cells, robust infiltration of cytotoxic CD8+ T and NK cells, and diminution of immune suppressor Treg cells, thereby amplifying anti-tumor immunity.

Copper-coordinated nanomedicine for the concurrent treatment of lung cancer through the induction of cuproptosis and apoptosis

The resistance of tumor cells to apoptosis often leads to chemoresistance and treatment failure in clinic. In this study, we have developed a Cu2+-coordinated lignosulfonate (CLS) /doxorubicin (DOX) biological complex (referred to as LCD) with the aim of overcoming cellular resistance to apoptosis for combined lung cancer therapy. The copper complexes modified by CLS exhibit significant water solubility and excellent in vivo biocompatibility. The proportion of copper in the composite is simultaneously increased. Due to the coordination and π-π stacking effects, the self-assembled LCD exhibits nanometer-scale particle size, a narrow and homogeneous grain distribution, as well as excellent dispersion stability. Furthermore, LCD has the potential to disassemble in the presence of high levels of glutathione (GSH) and low pH, leading to effective drug release. Cu2+-mediated cuproptosis can lead to the down-regulation of FDX1 and DLAT protein expression by reducing mitochondrial membrane potential, resulting in non-apoptotic programmed cell death (PCD) regardless of cellular resistance to apoptosis. Moreover, the released DOX not only exhibits a preference for localizing in the cell nucleus to induce apoptosis for combined chemotherapy, but also generates a substantial amount of H2O2. This H2O2 further produces ROS to induce apoptosis through Fenton reaction with Cu2+. LCD demonstrates significant superiority over monotherapy in inhibiting tumor growth while minimizing systemic toxicity through the combined action of cuproptosis and apoptosis. This study may provide a potential avenue for the advancement of self-delivery nanomedicine to overcome resistance to apoptosis in tumor therapy.

MG132-mediated Suppression of the Ubiquitin-proteasome Pathway Enhances the Sensitivity of Endometrial Cancer Cells to Cisplatin.

Tumor cell resistance to cisplatin is a common challenge in endometrial cancer chemotherapy, stemming from various mechanisms. Targeted therapies using proteasome inhibitors, such as MG132, have been investigated to enhance cisplatin sensitivity, potentially offering a novel treatment approach. The aim of this study was to investigate the effects of MG132 on cisplatin sensitivity in the human endometrial cancer (EC) cell line RL95-2, focusing on cell proliferation, apoptosis, and cell signaling. Human endometrial cancer RL95-2 cells were exposed to MG132, and cell viability was assessed in a dose-dependent manner. The study evaluated the effect of MG132 on cisplatin-induced proliferation inhibition and apoptosis, correlating with caspase-3 activation and reactive oxygen species (ROS) upregulation. Additionally, we examined the inhibition of the ubiquitin-proteasome system and the expression of pro-inflammatory cytokines IL-1β, IL-6, IL-8, and IL-13 during MG132 and cisplatin co-administration. MG132 exposure significantly reduced cell viability in a dose-dependent manner. It augmented cisplatin- induced proliferation inhibition and enhanced apoptosis, correlating with caspase-3 activation and ROS upregulation. Molecular analysis revealed a profound inhibition of the ubiquitin-proteasome system. MG132 also significantly increased the expression of cisplatin-induced pro-inflammatory cytokines, suggesting a transition from chronic to acute inflammation. MG132 enhances the therapeutic efficacy of cisplatin in human EC cells by suppressing the ubiquitin- proteasome pathway, reducing cell viability, enhancing apoptosis, and shifting the inflammatory response. These findings highlighted the potential of MG132 as an adjuvant in endometrial cancer chemotherapy. Further research is needed to explore detailed mechanisms and clinical applications of this combination therapy.

Redox Status and Protein Glutathionylation in Binase-Treated HPV16-Positive SiHa Carcinoma Cells

Human papillomavirus type 16 (HPV16) belongs to viruses of the high-risk type and is associated by overexpression of E6 and E7 oncoproteins, which determine the oncogenic properties of the virus, such as immortalization and malignant transformation of proliferating epithelial cells. The biogenesis of redox-sensitive proteins E6 and E7 at the early stages of viral infection leads to blocking of the cell antioxidant defense system and ubiquintin-dependent degradation of p53 and Rb tumor suppressors. Maintaining high rates of tumor cell proliferation contributes to an increase in the level of reactive oxygen species (ROS) and a shift in the redox balance towards oxidative processes. Reduced glutathione (GSH) provides antioxidant protection to tumor cells through S-glutathionylation of thiol groups of redox-sensitive proteins, which leads to the appearance of multidrug-resistant forms of cancer. In this regard, drugs restoring redox balance and increasing susceptibility to antitumor therapy are of particular importance. We have established that, Bacillus pumilus RNase (binase) modulates the redox-dependent regulatory mechanisms that ensure tumor cell resistance to apoptosis in HPV-16-positive SiHa cells of cervical squamous cell carcinoma,. Binase in nontoxic concentrations initiates a number of pre-apoptogenic changes, i.e., decreases ROS and reduced glutathione (GSH) levels, suppresses the expression of the E6 oncoprotein, activates the expression of the p53 tumor suppressor, and reduces the mitochondrial potential of tumor cells. Binase-induced disruption of the integrity of the mitochondrial membrane is a signal for activation of the mitochondrial apoptosis pathway.

The molecular mechanisms of chemotherapeutic resistance in tumors (Review).

Chemotherapy remains a prevalent treatment for a wide range of tumors; however, the majority of patients undergoing conventional chemotherapy experience varying levels of chemoresistance, ultimately leading to suboptimal outcomes. The present article provided an in‑depth review of chemotherapy resistance in tumors, emphasizing the underlying factors contributing to this resistance in tumor cells. It also explored recent advancements in the identification of key molecules and molecular mechanisms within the primary chemoresistant pathways.

Tumor Cell Spatial Organization Directs EGFR/RAS/RAF Pathway Primary Therapy Resistance through YAP Signaling.

Non-small cell lung cancers (NSCLC) harboring common mutations in EGFR and KRAS characteristically respond transiently to targeted therapies against those mutations, but invariably, tumors recur and progress. Resistance often emerges through mutations in the therapeutic target or activation of alternative signaling pathways. Mechanisms of acute tumor cell resistance to initial EGFR (EGFRi) or KRASG12C (G12Ci) pathway inhibition remain poorly understood. Our study reveals that acute response to EGFR/RAS/RAF-pathway inhibition is spatial and culture context specific. In vivo, EGFR mutant tumor xenografts shrink by > 90% following acute EGFRi therapy, and residual tumor cells are associated with dense stroma and have increased nuclear YAP. Interestingly, in vitro EGFRi induced cell cycle arrest in NSCLC cells grown in monolayer, while 3D spheroids preferentially die upon inhibitor treatment. We find differential YAP nuclear localization and activity, driven by the distinct culture conditions, as a common resistance mechanism for selective EGFR/KRAS/BRAF pathway therapies. Forced expression of the YAPS127A mutant partially protects cells from EGFR-mediated cell death in spheroid culture. These studies identify YAP activation in monolayer culture as a non-genetic mechanism of acute EGFR/KRAS/BRAF therapy resistance, highlighting that monolayer vs spheroid cell culture systems can model distinct stages of patient cancer progression.

Exploring Novel Therapeutic Breakthroughs for Cancers: Potential Roles of miRNAs

MicroRNAs (miRNAs) are small non-coding RNAs, 19–25 nucleotides in length, that regulate gene expression. miRNAs are involved in various cellular, biological, and pathological activities, including the development and progression of malignant tumors. Numerous studies have highlighted the significant roles of miRNA deregulation in various cancer types, involving critical pathways such as gene deletions and amplifications, abnormal epigenetic changes, and dysfunctional miRNA regulatory systems. miRNAs can function both as oncogenes and tumor suppressor genes in different contexts. Several cancer hallmarks are associated with deregulated miRNAs, including resistance to cell death, metastasis, sustained proliferative signaling, promotion of angiogenesis, and the suppression of growth factors. Recent research has demonstrated that miRNAs contribute to drug resistance in tumor cells by targeting genes linked to drug resistance or by influencing genes that regulate the cell cycle, apoptosis, and proliferation. A single miRNA often has tissue-specific regulatory functions and can affect multiple genes. Various miRNA types have been identified as potential biomarkers for tumor diagnosis and critical targets for novel therapeutic approaches. This review aims to explore the role of miRNAs in cancer progression, metastasis, and potential therapeutic interventions.