Functional Activity of Circulating Phagocytes as Potential Pretreatment Marker of Tumor Drug Resistance

The aim of this work was a study of the functional activity of neutrophils and peripheral blood monocytes in rats with the transplanted Walker carcinosarcoma as potential predictors of the sensitivity of this tumor to doxorubicin treatment. This study provides an evidence that such indices of the functional activity of circulating phagocytes of the tumor-bearing rats as the quantity and the phagocytosis intensity of monocytes, as well as the intensity of ROS production by monocytes and neutrophils, may reflect the degree of sensitivity of the tumor to doxorubicin. So it was shown that the growth of the resistant tumor caused a significant increase of the number of circulating phagocytic cells and the intensity of phagocytosis by more than 100% (p < 0.001) compared with the corresponding indices of intact rats and rats with the parental variant of the tumor. The ability of blood mono-cytes and neutrophils of rats with a resistant tumor to produce ROS was also significantly different from that in intact rats and animals with the parental carcinosarcoma variant. The predictive value of these indices is especially important in the dynamic monitoring of the development of tumor drug resistance during long-term cancer chemotherapy. Considering the standard 2 - 3 week interval between the courses of cancer therapy and the short lifetime of circulating phagocytes, an assessment of the indices of their functional activity before each subsequent course can be considered as a pretreatment assessment. Meanwhile, further studies are needed to determine the spectrum of malignant neoplasms for which the degree of tumor drug resistance correlates with the functional activity of circulating phagocytes.

Jaridon 6, a natural autophagy inducer, anti-gastric resistance in vivo and in vitro

OBJECTIVE Tumor resistant is the main cause leading to treatment failure.Tumor resistant is related to many aspect of tumor.Jaridon 6 is a new sesquiterpene come from Rabdosia rubescens extacted by our research team previously,have been tested having more obvious advantage than other anti-cancer drugs on tumor-resistant cells including a PTX-resistant gastric cancer cell.But how does the product work?In this paper,we have researched the effect and specific mechanism of Jaridon 6 on gastric-resistant.METHODS In the test,we have adopted vivo and vitro tests to identify the effect of Jaridon 6 on different gastric cancer-resistant cell.The MTT results,Flow test,Western blotting and nude test all verified the anti-cancer of Jaridon 6 on MGC803/PTX gastric resistant cell.We have also used scarifica⁃tion test and transwell tests and Western blotting to testify the inhibition action on EMT by Jaridon 6.The TEM and immu⁃nofluorescence tests have proved the induction autophagy of Jaridon 6.Immunohistochemical tests have been taken to assure the action of Jaridon 6 on EMT,autophagy and PI3K pathway in vivo.RESULTS Jaridon 6 could inhibite the gastric cancer resistant cell in vivo and in vitro.From the mechanism,the inhibiter of 3-MA or LY2940004 have proved the action on PI3K pathway and autophagy by Jaridon 6.Jaridon 6 could induce autophagy in tumor-resistant cells by inhibiting PI3K/AKT pathway.Except that,Jaridon 6 could inhibite the EMT of gastric cancer resistant cell.CONCLUSION Jaridon 6 could be considered for curing gastric cancer resistance,especially for PTX-resistance.Jaridon 6 is a natural autophagy inducer.

Emerging roles of 3D-culture systems in tackling tumor drug resistance

Drug resistance that affects patients universally is a major challenge in cancer therapy.The development of drug resistance in cancer cells is a multifactor event,and its process involves numerous mechanisms that allow these cells to evade the effect of treatments.As a result,the need to understand the molecular mechanisms underlying cancer drug sensitivity is imperative.Traditional 2D cell culture systems have been utilized to study drug resistance,but they often fail to mimic the 3D milieu and the architecture of real tissues and cell-cell interactions.As a result of this,3D cell culture systems are now considered a comprehensive model to study drug resistance in vitro.Cancer cells exhibit an in vivo behavior when grown in a three-dimensional environment and react to therapy more physiologically.In this review,we discuss the relevance of main 3D culture systems in the study of potential approaches to overcome drug resistance and in the identification of personalized drug targets with the aim of developing patient-specific treatment strategies that can be put in place when resistance emerges.

Systemic therapy in gastrointestinal stromal tumors

Gastrointestinal stromal tumors(GISTs)are the most common type of soft tissue sarcoma in the gastrointestinal tract.Most GISTs have been attributed to activated gain-of-function mutations in either KIT or platelet-derived growth factor receptorα,making these molecular features essential targets for therapeutic interventions.Although surgery is the standard treatment for localized GISTs,patients often experience relapse and disease progression even after surgery.In recent years,targeted therapy has significantly improved the prognosis of patients with advanced GISTs.Imatinib mesylate,a KIT inhibitor,is the first-line treatment for advanced GISTs and has revolutionized the treatment of this disease.However,drug resistance remains a major issue with imatinib treatment,as a significant majority of patients become resistant to imatinib either after initiation or after 2–3 years of treatment.Consequently,novel tyrosine kinase inhibitors such as sunitinib,regorafenib,ripretinib,and avapritinib have been introduced to address drug resistance.Immunotherapy has emerged as a potential approach for the treatment of advanced GISTs.This review comprehensively summarizes the pathogenesis of GISTs and the development of targeted therapies and immunotherapies,provides an overview of the emergence of drug resistance in advanced GISTs,and discusses the challenges and prospects associated with the treatment of GISTs.

Phytic acid-modified CeO_(2) as Ca^(2+) inhibitor for a security reversal of tumor drug resistance

Ca^(2+)plays critical roles in the development of diseases,whereas existing various Ca regulation methods have been greatly restricted in their clinical applications due to their high toxicity and inefficiency.To solve this issue,with the help of Ca overexpressed tumor drug resistance model,the phytic acid(PA)-modified CeO_(2) nano-inhibitors have been rationally designed as an unprecedentedly safe and efficient Ca2+inhibitor to successfully reverse tumor drug resistance through Ca^(2+)negative regulation strategy.Using doxorubicin(Dox)as a model chemotherapeutic drug,the Ca^(2+)nano-inhibitors efficiently deprived intracellular excessive free Ca2+,suppressed P-glycoprotein(P-gp)expression and significantly enhanced intracellular drug accumulation in Dox-resistant tumor cells.This Ca^(2+)negative regulation strategy improved the intratumoral Dox concentration by a factor of 12.4 and nearly eradicated tumors without obvious adverse effects.Besides,nanocerias as pH-regulated nanozyme greatly alleviated the adverse effects of chemotherapeutic drug on normal cells/organs and substantially improved survivals of mice.We anticipate that this safe and effective Ca^(2+)negative regulation strategy has potentials to conquer the pitfalls of traditional Ca inhibitors,improve therapeutic efficacy of common chemotherapeutic drugs and serves as a facile and effective treatment platform of other Ca^(2+) associated diseases.

Repurposing drugs for solid tumor treatment:focus on immune checkpoint inhibitors

Cancer remains a significant global health challenge with limited treatment options beyond systemic therapies,such as chemotherapy,radiotherapy,and molecular targeted therapy.Immunotherapy has emerged as a promising therapeutic modality but the efficacy has plateaued,which therefore provides limited benefits to patients with cancer.Identification of more effective approaches to improve patient outcomes and extend survival are urgently needed.Drug repurposing has emerged as an attractive strategy for drug development and has recently garnered considerable interest.This review comprehensively analyses the efficacy of various repurposed drugs,such as transforming growth factor-beta(TGF-β)inhibitors,metformin,receptor activator of nuclear factor-κB ligand(RANKL)inhibitors,granulocyte macrophage colony-stimulating factor(GM-CSF),thymosinα1(Tα1),aspirin,and bisphosphonate,in tumorigenesis with a specific focus on their impact on tumor immunology and immunotherapy.Additionally,we present a concise overview of the current preclinical and clinical studies investigating the potential therapeutic synergies achieved by combining these agents with immune checkpoint inhibitors.

Analysis of Pathogen Distribution and Drug Resistance of Nosocomial Infections Accompanied in Patients with Malignant Tumor

Objective： To investigate the pathogen distribution and drug resistance of nosocomial infections accompanied in patients with malignant tumor. Methods： The pathogen culture and drug-sensitivity data of 107 specimens isolated from malignant tumor patients accompanied with nosocomial infection were retrospectively analyzed. Results： Among 118 strains of pathogens isolated from 107 specimens, 77 were gram-negative bacillus（65.3%）, 26 were gram-positive coccus（65.3%）, and 15 were fungus（12.7%）. Eleven specimens were revealed to have combined infection of bacterium and fungus. Gram-negative bacillus showed high sensitivity to amikacin, ciprofloxacin, and tienam. Gram-positive cocci were highly sensitive to tienam and vancomycin. The bacteria were resistant to other antibiotics in different degrees, Vancomycin-resistant staphylococcus was not detected, Candida was sensitive to antifungals. Conclusion： Conditional pathogenic bacteria were mainly responsible for nosocomial infections in malignant tumor patients with considerable drug resistance. This shows that bacterial tests and the rational use of antibiotics should be emphasized in clinical practice to prevent the formation of drug resistant strains and further endogenous infections.

Subpopulation cooperation renders drug resistance of hepatobiliary tumor organoids

Hepatobiliary tumors are of high grade of heterogeneity, which is recognized as a key contributor to drug resistance and poor disease prognosis. However, the intrinsic mechanism between heterogeneity and drug response in hepatobiliary tumor is still largely unknown. Using tumor organoid models, Wang and her colleagues have found that cooperation among distinct subpopulations might be a key mechanism for drug resistance in hepatobiliary tumor.

Histone modification as a drug resistance driver in brain tumors

Patients with brain tumors,specifically,malignant forms such as glioblastoma,medulloblastoma and ependymoma,exhibit dismal survival rates despite advances in treatment strategies.Chemotherapeutics,the primary adjuvant treatment for human brain tumors following surgery,commonly lack efficacy due to either intrinsic or acquired drug resistance.New treatments targeting epigenetic factors are being explored.Post-translational histone modification provides a critical regulatory platform for processes such as chromosome condensation and segregation,apoptosis,gene transcription,and DNA replication and repair.This work reviews how aberrant histone modifications and alterations in histone-modifying enzymes can drive the acquisition of drug resistance in brain tumors.Elucidating these mechanisms should lead to new treatments for overcoming drug resistance.

Tumor microenvironment involvement in colorectal cancer progression via Wnt/β-catenin pathway:Providing understanding of the complex mechanisms of chemoresistance

Colorectal cancer(CRC)continues to be one of the main causes of death from cancer because patients progress unfavorably due to resistance to current therapies.Dysregulation of the Wnt/β-catenin pathway plays a fundamental role in the genesis and progression of several types of cancer,including CRC.In many subtypes of CRC,hyperactivation of theβ-catenin pathway is associated with mutations of the adenomatous polyposis coli gene.However,it can also be associated with other causes.In recent years,studies of the tumor microenvironment(TME)have demonstrated its importance in the development and progression of CRC.In this tumor nest,several cell types,structures,and biomolecules interact with neoplastic cells to pave the way for the spread of the disease.Cross-communications between tumor cells and the TME are then established primarily through paracrine factors,which trigger the activation of numerous signaling pathways.Crucial advances in the field of oncology have been made in the last decade.This Minireview aims to actualize what is known about the central role of the Wnt/β-catenin pathway in CRC chemoresistance and aggressiveness,focusing on crosscommunication between CRC cells and the TME.Through this analysis,our main objective was to increase the understanding of this complex disease considering a more global context.Since many treatments for advanced CRC fail due to mechanisms involving chemoresistance,the data here exposed and analyzed are of great interest for the development of novel and effective therapies.

Co-delivery of resveratrol and docetaxel via polymeric micelles to improve the treatment of drug-resistant tumors

Co-delivery of anti-cancer drugs is promising to improve the efficacy of cancer treatment.This study was aiming to investigate the potential of concurrent delivery of resveratrol(RES)and docetaxel(DTX)via polymeric nanocarriers to treat breast cancer.To this end,methoxyl poly(ethylene glycol)-poly(D,L-lactide)copolymer(mPEG-PDLA)was prepared and characterized using FTIR and 1H NMR,and their molecular weights were determined by GPC.Isobologram analysis and combination index calculation were performed to find the optimal ratio between RES and DTX to against human breast adenocarcinoma cell line(MCF-7 cells).Subsequently,RES and DTX were loaded in the mPEG-PDLA micelles simultaneously,and the morphology,particle size distribution,in vitro release,pharmacokinetic profiles,as well as cytotoxicity to the MCF-7 cells were characterized.IC50 of RES and DTX in MCF-7 cells were determined to be 23.0μg/ml and 10.4μg/ml,respectively,while a lower IC50 of 4.8μg/ml of the combination of RES and DTX was obtained.The combination of RES and DTX at a ratio of 1:1(w/w)generated stronger synergistic effect than other ratios in the MCF-7 cells.RES and DTX loaded mPEG-PDLA micelles exhibited prolonged release profiles,and enhanced cytotoxicity in vitro against MCF-7 cells.The AUC(0→t)of DTX and RES in mPEG-PDLA micelles after i.v.administration to rats were 3.0-fold and 1.6-fold higher than that of i.v.injections of the individual drugs.These findings indicated that the co-delivery of RES and DTX using mPEG-PDLA micelles could have better treatment of tumors.

Novel insights into mTOR signalling pathways: A paradigm for targeted tumor therapy

As a crucial protein kinase,the mammalian target of rapamycin(mTOR)intimately controls essential cellular processes like cell development,proliferation,metabolism,and other crucial activities.Different cancers and disorders have been linked to imbalances in mTOR's regulatory systems.Multiple mTOR inhibitor therapy has recently acquired popularity as a method of treating cancers brought on by abnormal signal transduction pathways.We also explore potential processes behind tumor cell resistance to mTOR inhibitors and suggest workarounds to overcome this challenge.We hold the potential to pioneer cutting-edge methods for tumor therapy by methodically examining the complex mTOR signaling system and its regulatory complexity.Increasing our knowledge of mTOR-related mechanisms not only creates opportunities for cutting-edge methods to target and treat cancers but also has the potential to improve patient outcomes and general quality of life significantly.This review paper explores the most recent developments in understanding mTOR signaling pathways and the use of mTOR inhibitors in treating tumors.

EFFECT OF ASCORBIC ACID ON DNA SYNTHESIS,INTRACELLULAR ACCUMULATION OF ADM AND ADM RESISTANCE OF TUMOR CELL LINES

Objective: To determine the effect of ascorbic acid (AA) on DNA synthesis, intracellular accumulation of ADM and ADM resistance of tumor cell lines. Methods: K562, K562/ADM and KB cell lines were used to study the effect of ascorbic acid on DNA synthesis, intracellular accumulation of ADM and ADM resistance by fluid scintillometry, MTT method, spectrofluorophotometry and immunocytochemistry. Results: Results showed that AA was capable of inhibiting DNA synthesis of K562 and K562/ADM in a dosedependence fashion, but not KB cell line, and significantly reducing ADM sensitivity in K562 and KB cell lines, as well as potentiating obviously ADM resistance in K562/ADM cell line. Conclusion: These effects of AA may be closely correlated with significant elevation of intracellular accumulation of ADM in KB cell line, and significant reduction of that in K562 and K562/ADM cell lines but possibly not correlated with the expression of Pglycoprotein.

The inhibitory effect of adenosine on tumor adaptive immunity and intervention strategies

Adenosine(Ado)is significantly elevated in the tumor microenvironment(TME)compared to normal tissues.It binds to adenosine receptors(AdoRs),suppressing tumor antigen presentation and immune cell activation,thereby inhibiting tumor adaptive immunity.Ado downregulates major histocompatibility complex II(MHC II)and co-stimulatory factors on dendritic cells(DCs)and macrophages,inhibiting antigen presentation.It suppresses anti-tumor cytokine secretion and T cell activation by disrupting T cell receptor(TCR)binding and signal transduction.Ado also inhibits chemokine secretion and KCa3.1 channel activity,impeding effector T cell trafficking and infiltration into the tumor site.Furthermore,Ado diminishes T cell cytotoxicity against tumor cells by promoting immune-suppressive cytokine secretion,upregulating immune checkpoint proteins,and enhancing immune-suppressive cell activity.Reducing Ado production in the TME can significantly enhance anti-tumor immune responses and improve the efficacy of other immunotherapies.Preclinical and clinical development of inhibitors targeting Ado generation or AdoRs is underway.Therefore,this article will summarize and analyze the inhibitory effects and molecular mechanisms of Ado on tumor adaptive immunity,as well as provide an overview of the latest advancements in targeting Ado pathways in anti-tumor immune responses.

Distribution and drug resistance of pathogenic bacteria isolated from cancer hospital in 2013

Objective： To understand distribution and drug resistance of pathogenic bacteria from a specialized cancer hospital in 2013 in order to provide a basis for rational clinical antimicrobial agents. Methods： Pathogenic bacteria identification and drug sensitivity tests were performed with a VITEK 2 compact automatic identification system and data were analyzed using WHONET5.6 software.Results： Of the 1,378 strains tested, 980 were Gram-negative bacilli, accounting for 71.1%, in which Klebsiella pneumonia, Escherichia coli and Pseudomonas aeruginosa were the dominant strains. We found 328 Gram-positive coccus, accounting for 23.8%, in which the amount of Staphylococcus aureus was the highest. We identified 46 fungi, accounting for 4.1%. According to the departmental distribution within the hospital, the surgical departments isolated the major strains, accounting for 49.7%. According to disease types, lung cancer, intestinal cancer and esophagus cancer were the top three, accounting for 20.9%, 17.3% and 14.2%, respectively. No strains were resistant to imipenem, ertapenem or vancomycin.Conclusions： Pathogenic bacteria isolated from the specialized cancer hospital have different resistance rates compared to commonly used antimicrobial agents; therefore antimicrobial agents to reduce the morbidity and mortality of infections should be used.

Anticancer Drug Resistance of HeLa Cells Transfected With Rat Glutathione S-transferase pi Gene

To establish a cytologic expressing system of rat glutathione S-transferase pi (GST-pi) cDNA for detecting the resistance of HeLa cells to anticancer drugs. Methods The assessment was made with various anticancer drugs (adriamycin, mitomycin, cisplatinum and vincristine) that showed different cytotoxicities in transfectant HeLa cells with pSV-GT containing rat GST-pi cDNA (HeLa/pSV-GT) or control pSV-neo (HeLa/pSV-neo). Expression levels of GST-pi mRNA in HeLa/pSV-GT and HeLa/pSV-neo were measured by in situ hybridization using Digoxin-labelled cDNA probe. Results HeLa/pSV-GT expressed significantly high degree of GST-pi mRNA, whereas both HeLa/pSV-neo and HeLa cells had very low expression. Cytotoxicities of HeLa/pSV-GT and HeLa/pSV-neo with 4 anticancer drugs were measured by MTT assay. Drug concentrations for yielding 50% inhibition (IC50) in HeLa/pSV-GT by adriamycin, mitomycin and cisplatinum were 70.13 靏/mL, 10.95 靏/mL and 16.52 靏/mL, respectively. In contrast, IC50 in HeLa/pSV-neo was 10.34 靏/mL, 7.48 靏/mL and 13.70 靏/mL, respectively. The cytotoxicities of vincristine on both HeLa/pSV-GT and HeLa/pSV-neo were not significantly different. Conclusions Our findings suggest that HeLa/pSV-GT containing rat GST-pi cDNA is resistant to some anticancer drugs due to overexpression of GST-pi. Also, HeLa/pSV-GT cell line could serve as a useful cytogenetic model for further research.

Research advances of secretory proteins in malignant tumors

Secretory proteins in tumor tissues are important components of the tumor microenvironment.Secretory proteins act on tumor cells or stromal cells or mediate interactions between tumor cells and stromal cells,thereby affecting tumor progression and clinical treatment efficacy.In this paper,recent research advances in secretory proteins in malignant tumors are reviewed.

Drug resistance and new therapies in colorectal cancer

Colorectal cancer(CRC) is often diagnosed at an advanced stage when tumor cell dissemination has taken place. Chemo-and targeted therapies provide only a limited increase of overall survival for these patients. The major reason for clinical outcome finds its origin in therapy resistance. Escape mechanisms to both chemo-and targeted therapy remain the main culprits. Here, we evaluate major resistant mechanisms and elaborate on potential new therapies. Amongst promising therapies is α-amanitin antibodydrug conjugate targeting hemizygous p53 loss. It becomes clear that a dynamic interaction with the tumor microenvironment exists and that this dictates therapeutic outcome. In addition, CRC displays a limited response to checkpoint inhibitors, as only a minority of patients with microsatellite instable high tumors is susceptible. In this review, we highlight new developments with clinical potentials to augment responses to checkpoint inhibitors.

Effects of Taxotere on invasive potential and multidrug resistance phenotype in pancreatic carcinoma cell line SUIT-2

INTRODUCTIONDevelopment of drug-resistance to chemotherapyand subsequent metastasis of tumor are primarilyresponsible for treatment failure and the death fromcancer. There have been many previous studies onthe relationship between expression of multidrugresistance (MDR) phenotype P-glycoprotein (P-gp)and the malignant properties of tumors, but theresults are often conflicting[1-8]. The difference intumor types or MDR phenotype induced by specificagents might account for this discrepancy. Taxotere(TXT), a member of the family of taxanes, hasantitumor activity through its effect of promotingthe polymerization of tubulin[9,10].

Gastrointestinal Stromal Tumors in the 21^stCentury

Gastrointestinal stromal tumours (GISTs) are rare mesenchymal lesions accounting for only 0.2% of all gastrointestinal neoplasms. These tumors arise from the interstitial cells of Cajal, with mutations described in proto-oncogenes such as KIT, PDGFRA, DOG-1, and SDH. The majority of these lesions are asymptomatic, thus the true incidence remains unknown. While patients typically undergo initial endoscopy, CT scan and/or MRI, findings are often nonspecific and require a biopsy to identify the tumor. As such, immunohistochemical evaluation is the gold-standard for the accurate diagnosis of GIST. Though surgical excision remains the gold-standard for curative management, the discovery of imatinib, a tyrosine kinase inhibitor (TKI), has revolutionized the treatment of GIST in the 21st?century as a “prototype” of molecular targeted therapy for solid tumors. Risk assessment for recurrence divides these tumors into low and high-risk categories. In the latter, a role for adjuvant therapy with TKI confers a significantly better prognosis than previously observed. However, secondary mutations conferring drug resistance remain an ongoing challenge for management, as few alternative treatment options are available for patients intolerant/refractory to TKI therapy. In this review, we summarize the epidemiology, molecular pathogenesis, clinical presentation, diagnosis, pathology features, management options, and prognostic features of GISTs.