Primary Drug Resistance Research Articles

Immune Disorders in Patients with Pulmonary Tuberculosis with Primary and Acquired Drug-Resistance of <i>Mycobacterium Tuberculosis</i>

The objective: to evaluate main parameters of cellular, humoral immunity and natural resistance in tuberculosis patients with primary and acquired multiple drug resistance; to study the correlation of these parameters with clinical and radiological manifestations.Subjects and Methods. A prospective study was conducted which included 169 patients with pulmonary tuberculosis, 80 of them were new cases of drug susceptible pulmonary tuberculosis and they made the Comparison Group (CG), and 89 patients suffered from multiple drug resistant tuberculosis and they made the Main Group (MG). The Main Group was divided into 2 subgroups: MG-1 – 40 patients with primary multiple drug resistant tuberculosis; MG-2 ‒ 49 patients who acquired drug resistance of Mycobacterium tuberculosis during treatment of tuberculosis.The immune assays included the lymphocyte blast transformation reaction (LBTR) to phytohemagglutinin and tuberculin (PPD), immunophenotyping of CD3+ and CD19+ cells; phagocytic index and phagocytic number were calculated; nitro blue tetrazolium test was used, concentrations of immunoglobulins and antimycobacterial antibodies were determined.Results. The clinical laboratory data demonstrated a more severe course of the disease in patients with multiple drug resistant tuberculosis, especially in those with acquired multiple drug resistant tuberculosis which was confirmed by the severity of immune deficiencies of the cellular immunity and innate resistance as well as by the overactivity of humoral immunity. The levels of CD3+ and LBTR reaction to PPD had a negative correlation with clinical manifestations and radiological features demonstrating the severity of pulmonary tuberculosis in patients with multiple drug resistance, especially in those with acquired multiple drug resistance; and CD19+ and antimycobacterial antibodies positively correlated with clinical manifestations and radiological signs.Conclusions. Parameters of cellular immunity and natural resistance were the lowest in the patients with acquired multiple drug resistance of Mycobacterium tuberculosis versus primary multiple drug resistance and drug susceptible Mycobacterium tuberculosis. Parameters of humoral immunity demonstrated the increased activity to compensate for the insufficiency of cellular immunity regardless of the type of resistance of Mycobacterium tuberculosis.

PRIMARY DRUG RESISTANT TUBERCULOSIS - THE CONCERN!

Tuberculosis is an airborne infection caused by mycobacterium tuberculosis. About 480000 people worldwide developed MDR TB in 2015,additionally 1,00,00 developed resistance to rifampicin and needed MDR TB treatment.MDR TB burden largely falls on China, India & the Russian Federation - which together account for nearly half of the global cases. The proportion of DR-TB cases among new cases is 2-3% and that among previously treated cases is 12-17%. Aims and objectives: To find the incidence of primary MDR TB in a tertiary care center in Navi Mumbai.Materials & Methods: A retrospective study of Culture and sensitivity reports of 100 patients was conducted.All underwent smear examination for AFB by ZNCF method.AFB Gene Xpert (CB-NAAT) and AFB culture and drug sensitivity. Results- In our study we found primary MDR to be 10 % while an additional 1 % was resistant to INH alone. All patients were HIV negative. Conclusion-The high proportion of Primary MDR-TB found in our study compels us to suggest that modalities to diagnose primary drug resistance tuberculosis should be made available to all newly diagnosed TB patients, irrespective of HIV status.

Identification of six hub genes in mantle cell lymphoma patients with BTKi resistance.

Bruton tyrosine kinase inhibitor (BTKi) resistance is an unsolved problem in the treatment of relapse/recurrence (R/R) mantle cell lymphoma (MCL). Although salvage therapy following ibrutinib resistance has been attempted in recent years, the survival of resistant patients was significantly reduced. Once ibrutinib-treated patients relapse, the 1-year survival rate is only 22%. Acquired drug resistance and primary drug resistance were found to relate closely to genetic mutations. The hub genes identification and clinical data analysis of patients resistant to BTKi based on the Chinese MCL gene mutation profile are worthy of exploration. Based on 28 MCL patients' mutation data and clinical data, 6 hub genes were screened by a gene panel of 69 genes and univariate Cox prognostic analysis. Prognosis and responses to salvage therapy regimen were analyzed. Patients with BTKi had less favorable clinical features at baseline. Chimeric antigen receptor T-cell (CAR-T) therapy yielded the best response among salvage treatments. The 6 hub genes were screened by a gene panel of 69 genes (GP79) which might be a potential predictor for MCL patients with BTKi resistance. The clinical characteristics of BTKi resistance in MCL patients were summarized, and 6 hub genes were identified to provide ideas and suggestions for further research.

Associating resistance to immune checkpoint inhibitors with immunological escape in colorectal cancer.

Colorectal cancer is a common malignant tumor that ranks third in incidence and second in mortality worldwide, and surgery in conjunction with chemotherapy and radiotherapy remains the most common treatment option. As a result of radiotherapy’s severe side effects and dismal survival rates, it is anticipated that more alternatives may emerge. Immunotherapy, a breakthrough treatment, has made significant strides in colorectal cancer over the past few years, overcoming specialized therapy, which has more selectivity and a higher survival prognosis than chemoradiotherapy. Among these, immune checkpoint inhibitor therapy has emerged as the primary immunotherapy for colorectal cancer nowadays. Nonetheless, as the use of immune checkpoint inhibitor has expanded, resistance has arisen inevitably. Immune escape is the primary cause of non-response and resistance to immune checkpoint inhibitors. That is the development of primary and secondary drug resistance. In this article, we cover the immune therapy-related colorectal cancer staging, the specific immune checkpoint inhibitors treatment mechanism, and the tumor microenvironment and immune escape routes of immunosuppressive cells that may be associated with immune checkpoint inhibitors resistance reversal. The objective is to provide better therapeutic concepts for clinical results and to increase the number of individuals who can benefit from colorectal cancer immunotherapy.

The Interaction of the IFNγ/JAK/STAT1 and JAK/STAT3 Signalling Pathways in EGFR-Mutated Lung Adenocarcinoma Cells.

Purpose It was reported that the EGFR (epidermal growth factor receptor) mutation status was related to primary immune resistance in NSCLC (non-small-cell lung cancer). ICIs (immune checkpoint inhibitors) have poor efficacy and large side effects for people with EGFR mutation. EGFR mutation was considered as a sign of immune therapeutic resistance, but its underlying mechanism is difficult to be determined. Combined with our research basis, we tried to explore the possible mechanism of primary drug resistance in EFGR mutant lung adenocarcinoma through the interaction between the JAK/STAT1 and JAK/STAT3 pathway. Materials and Methods Cell apoptosis and viability test were used to study the role of the JAK/STAT signalling pathway in lung adenocarcinoma cell survival. Western blot, RT-PCR, and flow cytometry were employed to explore the changes of expression in JAK1/2, STAT1/3, PD-L1, and related signal molecules in the case of activation or inhibition of the JAK/STAT3 signalling pathway. Results With inhibition of inhibiting the JAK/STAT3 signalling pathway by STAT3 inhibitors, we found IFNγ-JAK-STAT1 pathway activation by IFNγ could further keep lung adenocarcinoma cells from proliferation and promote its apoptosis. The inhibition of the JAK/STAT3 pathway results in the upregulation of JAK1/2, STAT1, IRF1, IRF9, and PD-L1 and downregulation of STAT3 and SOCS1. Conclusions The absence of the IFNγ-JAK-STAT1 signal pathway is one of the main mechanisms for the ICI endogenous resistance. The abnormal activation of the downstream JAK/STAT3 pathway in cells with EGFR mutation may have antagonistic effects on the STAT1 induced antitumor immune response, which may cause the IFNγ-JAK-STAT1 pathway to lose its function. The mechanism may result in production of the immune tolerance of the EGFR mutant, which promotes immune escape.

Prevalence of resistance mutations associated with integrase inhibitors in therapy-naive HIV-positive patients in Baoding, Hebei province, China.

Antiretroviral therapy (ART) regimens containing integrase strand transfer inhibitors (INSTIs) are the recommended treatment for human immunodeficiency virus type 1 (HIV-1)-infected patients in the most recent guidelines in China. In this study, we investigated INSTI resistance mutations in newly diagnosed therapy-naive HIV-positive patients in Baoding City, Hebei Province (China) to provide guidance for implementing routine INSTI-associated HIV-1 genotypic resistance testing. Plasma samples were collected from HIV-1-infected patients without treatment at Baoding People’s Hospital from January 2020 to December 2021. The part of HIV-1 pol gene encoding integrase was amplified, sequenced, and analyzed for INSTI resistance. Clinical data including demographic data, CD4+ T cell counts, HIV-RNA loads, and resistance mutations were collected. Treatment-naïve HIV-1 patients (n = 131) were enrolled. We identified ten genotypes, and the predominant genotype was CRF01_AE in 67 patients (51.15%), CRF07_ BC in 39 patients (29.77%), subtype B in 11 patients (8.40%), and other subtypes (CRF68_01B, 3.82%; CRF55_01B, 1.53%, CRF80_0107, 1.53%; URFs 1.53%; and CRF103_01B, CRF59_01B, and CRF65_cpx, 1.4% each). Four major (E138A, R263k, G140S, and S147G) and three accessory (H51Y, Q146QL, and S153F) INSTI-resistance mutations were observed (genotype CRF01_AE, three patients; genotype B, one patient; and genotype CRF07_BC, one patient), resulting in different degrees of resistance to the following five INSTIs: raltegravir, elvitegravir, dolutegravir, bictegravir, and cabotegravir. The overall resistance rate was 3.82% (5/131). All INSTI-resistant strains were cross-resistant. The primary INSTI drug resistance rate among newly diagnosed HIV-infected patients in Baoding was low, but monitoring and research on HIV INSTI resistance should be strengthened in Baoding because INSTI-based regimen prescriptions are anticipated to increase in the near future.

EP05.02-001 Early Treatment Failure Of Consolidation Durvalumab for Unresectable Stage III NSCLC: A Real-World Canadian Cohort

The use of consolidative durvalumab following concurrent chemoradiotherapy in unresectable Stage III NSCLC patients has contributed to improvement in patient outcome; however, some patients experience early treatment failure on durvalumab, characterized by primary drug resistance or toxicity requiring durvalumab termination. With clinical characteristics associated with early treatment failure on immunotherapy not well explored, this study investigated this phenomenon and endeavored to identify predictors associated with resistance or toxicity on durvalumab.

Single-cell phenotypic profiling to identify a set of immune cell protein biomarkers for relapsed and refractory diffuse large B cell lymphoma: A single-center study.

Diffuse large B-cell lymphoma (DLBCL) is the most common invasive type of non-Hodgkin lymphoma. Cell-of-origin (COO) classification is related to patients' prognoses. Primary drug resistance in treatment for DLBCL has been observed. The specific serum biomarkers in these patients who suffer from relapsed and refractory (R/R)-DLBCL remains unclear. In the current study, using single-cell RNA sequencing (scRNA-seq) and mass cytometry (CyTOF), we determined and verified immune cell biomarkers at the mRNA and protein levels in single-cell resolution from 18 diagnostic PBMC specimens collected from patients with R/R DLBCL. As controls, 5 PBMC specimens from healthy volunteers were obtained. We identified a panel of 35 surface marker genes for the features of R/R DLBCL unique cell cluster by scRNA-seq of 8 R/R DLBCL patient samples and validated its efficiency in an external cohort consisting of 10 R/R DLBCL patients by CyTOF. The cell clustering and dimension reduction were compared among R/R DLBCL samples in CyTOF Space with COO as well as the C-MYC expression designation. Immune cells from each patient occupied unique regions in the 32-dimensional phenotypic space with no apparent clustering of samples into discrete subtypes. Significant heterogeneity observed in subgroups was mainly attributed to individual differences among samples and not to expression differences in a single, homogeneous immune cell subpopulation. The marker panel showed reliability in labeling R/R DLBCL without any influence from COO stratification and C-MYC expression designation. Furthermore, we compared all the markers between R/R DLBCL and normal samples. A total of 12 biomarkers were significantly overexpressed in R/R DLBCL relative to the normal samples. Therefore, we further optimized the diagnostic biomarker panel of R/R DLBCL comprising CD82, CD55, CD36, CD63, CD59, IKZF1, CD69, CD163, CD14, CD226, CD84, and CD31. In summary, we developed a novel set of biomarkers for the diagnoses of patients with R/R DLBCL. Detections procedures at single-cell resolution provide precise biomarkers, which may substantially overcome intertumoral and intratumoral heterogeneity among primary samples. The findings confirmed that each case was unique and may comprise multiple, genetically distinct subclones.

Prevalence and transmission of pyrazinamide-resistant Mycobacterium tuberculosis in Hunan Province,China

Objective: To provide a scientific reference for the prevention and treatment of pyrazinamide-resistant tuberculosis (PZA-R TB), we analyzed the prevalence and risk factors of pyrazinamide-resistant tuberculosis in Hunan province and described the genotyping and clustering characteristics of the pyrazinamide-resistant Mycobacterium tuberculosis (PZA-R MTB) isolates. Methods: The drug susceptibility test results of first-line anti-tuberculosis drugs including isoniazid (INH), rifampicin (RFP), streptomycin (SM), ethambutol (EMB) and pyrazinamide (PZA), and the characteristics of patients were collected from 3 862 tuberculosis patients in Hunan Chest Hospital (Institute of Tuberculosis Control and Prevention) from January 2016 to December 2018. The prevalence of PZA-R TB was calculated and risk factors were analyzed by univariate and multivariable logistic regression analysis. Two hundred and twelve Mycobacterium tuberculosis isolates selected from June 2017 to June 2018 were genotyped using the 24-loci MIRU-VNTR system. The genetic difference value (h), and the Hunter-Gaston index (HGI) were used to evaluate the resolution and variation for the 24 loci. MIRU-VNTR results were analyzed using BioNumerics 5.0 software to conduct cluster analysis. Clustered isolates were further analyzed by pncA gene sequencing. Results: The rate of PZA-R TB among tuberculosis patients and MDR patients was 14.7%(566/3 862) and 60.5%(511/844), respectively. Multivariable logistic regression analysis showed that patients who were INH mono-resistance and MDR had a higher risk of developing PZA resistance, compared with TB patients who were pan-sensitive to anti-TB drugs (INH, RFP, SM, and EMB). The adjusted OR value (95%CI) was 13.08(5.67-30.18), 298.41(164.88-540.08), respectively, and P values were all less than 0.01. Clustering analysis showed that 65 strains formed 19 clusters, the clustering rate was 30.7%(65/212). Of 19 clusters, eight clusters had at least two isolates with identical pncA mutation types within each cluster. In eight clusters, cluster 4, 6, 16 had four, three, and two patients who lived in the same county, respectively, thus providing probable epidemiological links for the recent transmission of PZA-R Mycobacterium tuberculosis. At least 47.6%(101/212) of PZA drug-resistant TB patients were suggestive of primary drug resistance caused by transmission. Conclusions: The prevalence of PZA-R TB was severe in Hunan province. PZA susceptibility testing should be performed for isolates resistant to any first-line anti-tuberculosis drugs, especially for MDR-MTB isolates. Nearly half of tuberculosis patients were suggestive of primary drug resistance caused by transmission. The prevention and treatment strategy of PZA-R TB should focus on the standardized treatment and management of patients as well as control of the source of infection.

Barriers faced by patients in the diagnosis of multidrug-resistant tuberculosis in Brazil.

ABSTRACTOBJECTIVE To understand patients’ narratives about the barriers they faced in the diagnosis and treatment of multidrug-resistant tuberculosis, and their consequences in Rio de Janeiro State, Brazil.METHODS This is a qualitative cross-sectional study with non-probabilistic sampling. A theoretical saturation criterion was considered for composing the number of interviewees. Semi-structured interviews were conducted from August to December 2019 with 31 patients undergoing treatment for multidrug-resistant tuberculosis at an outpatient referral center in Rio de Janeiro. Data were transcribed and processed with the aid of the NVIVO software. Interviews were evaluated by content analysis, and their themes, cross-referenced with participants’ characterization data.RESULTS Our main findings were: a) participants show a high proportion of primary drug resistance, b) patients experience delays in the diagnosis and effective treatment of multidrug-resistant tuberculosis ; c) healthcare providers fail to value or seek the diagnosis of drug-resistant tuberculosis, thus beginning the inadequate treatment for drug-susceptible tuberculosis, d) primary health units show low report rates of active case-finding and contact monitoring, and e) patients show poor knowledge about the disease.CONCLUSIONS We need to improve referral systems, and access to the diagnosis and effective treatment of multidrug-resistant tuberculosis; conduct an active investigation of contacts; intensify the training of healthcare providers, in collaboration with medical and nursing schools, in both public and private systems; and promote campaigns to educate the population on tuberculosis signs and symptoms.

Ofloxacin resistance in multibacillary new leprosy cases from Purulia, West Bengal: a threat to effective secondary line treatment for rifampicin-resistant leprosy cases

Purulia is one of the high-endemic districts for leprosy in West Bengal (the eastern part of India). The annual new case detection rate (ANCDR) of leprosy in West Bengal is 6.04/100000 (DGHS 2019-20). Our earlier report provided evidence of secondary drug resistance in relapse cases of leprosy. The aim of the current study was to observe primary drug resistance patterns for dapsone, rifampicin, and ofloxacin amongst new leprosy patients from Purulia, West Bengal in order to better understand the emergence of primary resistance to these drugs. In the present study, slit-skin smear samples were collected from 145 newly diagnosed leprosy cases from The Leprosy Mission (TLM) Purulia hospital between 2017 and 2018. DNA was extracted from these samples and the Mycobacterium leprae genome was analyzed for genes associated with drug resistance by polymerase chain reaction (PCR), followed by Sanger sequencing. Wild-type strain (Thai-53) and mouse footpad-derived drug-resistant strain (Z-4) were used as reference strains. Of 145 cases, 25 cases showed mutations in genes associated with resistance to rifampicin, dapsone, and ofloxacin (as described by the World Health Organization, rpoB, folP, and gyrA, respectively) through Sanger sequencing. Of these 25 cases, 16 cases showed mutations in ofloxacin, two cases showed mutations in combinations of ofloxacin and rifampicin, four cases showed a mutation only in rifampicin, one case showed mutations in combinations of rifampicin and dapsone, and two cases showed mutations only in dapsone. Results from this study indicated the emergence of resistance to antileprosy drugs in new cases of leprosy. As ofloxacin is the alternate drug for the treatment of rifampicin-resistant cases, the emergence of new cases with resistance to ofloxacin indicates that ofloxacin-resistant M. leprae strains are actively circulating in this endemic region (i.e., Purulia, West Bengal), posing challenges for the effective treatment of rifampicin-resistant cases.

Drug Resistance in Colorectal Cancer: From Mechanism to Clinic.

Simple SummaryChemotherapy, radiotherapy and molecularly targeted therapy could improve the prognosis of colorectal cancer (CRC) patients. Recently, immunotherapy, especially immune checkpoint inhibitors, has significantly improved the prognosis of some patients. However, drug resistance significantly reduces the usefulness of these drugs. Although research on the molecular mechanisms underlying the emergence of drug resistance is ongoing, the specific molecular mechanisms remain unclear. This article reviews the findings on the mechanisms of drug resistance in CRC patients in preclinical and clinical studies, which may provide valuable directions for future in-depth study of drug resistance.Colorectal cancer (CRC) is one of the leading causes of death worldwide. The 5-year survival rate is 90% for patients with early CRC, 70% for patients with locally advanced CRC, and 15% for patients with metastatic CRC (mCRC). In fact, most CRC patients are at an advanced stage at the time of diagnosis. Although chemotherapy, molecularly targeted therapy and immunotherapy have significantly improved patient survival, some patients are initially insensitive to these drugs or initially sensitive but quickly become insensitive, and the emergence of such primary and secondary drug resistance is a significant clinical challenge. The most direct cause of resistance is the aberrant anti-tumor drug metabolism, transportation or target. With more in-depth research, it is found that cell death pathways, carcinogenic signals, compensation feedback loop signal pathways and tumor immune microenvironment also play essential roles in the drug resistance mechanism. Here, we assess the current major mechanisms of CRC resistance and describe potential therapeutic interventions.

Advances in Treatment of Non-small Cell Lung Cancer Harboring EGFR Exon 20 Insertion Mutations

表皮生长因子受体（epidermal growth factor receptor, EGFR）外显子20插入突变是EGFR突变的第三大常见类别，约占所有EGFR突变阳性非小细胞肺癌（non-small cell lung cancer, NSCLC）的5%-12%。携带EGFR外显子20插入突变的NSCLC患者临床特征与“经典”EGFR激活突变人群相似，但预后很差。EGFR外显子20插入突变异质性高，可导致EGFR不同构象变化。大多数（几乎90%的病例）发生在α-C-螺旋后的Loop环结构区，最常报告的插入突变亚型为D770_N771 > ASVDN（A767_V769dupASV），突变频率为21%-28%。目前已知EGFR外显子20插入突变的NSCLC对既往已批准的EGFR酪氨酸激酶抑制剂原发性耐药，而且对传统化疗和免疫治疗也不敏感。近期Amivantamab与Mobocertinib在美国的获批改变了EGFR外显子20插入突变的NSCLC患者的治疗模式。此外，针对NSCLC EGFR外显子20插入突变的其他新型靶向药物正在研发中，期待为该类患者带来更多生存获益。本文就近年来伴有EGFR外显子20插入突变的NSCLC的临床研究进展进行归纳总结，旨在为该类患者的临床治疗提供参考。

A real world study on the relationship between drug resistance of targeted therapy and prognosis of HER-2-positive advanced breast cancer

Objective: To explore the effect of primary and acquired resistance to anti-human epidermal growth factor receptor 2 (HER-2) on the overall survival of patients with HER-2 positive advanced breast cancer. Methods: The clinical characteristics of HER-2 positive patients with advanced breast cancer admitted to Cancer Hospital of Chinese Academy of Medical Sciences from January 1998 to December 2018 were collected, and their neoadjuvant/adjuvant and advanced three-line chemotherapy were summarized. Among them, targeted drugs for HER-2 included trastuzumab, pertuzumab, T-DM1, RC48-ADC, lapatinib, pyrotinib, allitinib, sipatinib, seratinib. Based on the duration of benefit from anti HER-2 treatment, the patients were divided into two groups: primary anti HER-2 resistance group and acquired anti HER-2 resistance group. In this study, the overall survival (OS) was used as the main end point. Kaplan-Meier analysis and Cox proportional risk regression model were used to analyze the effects of different drug resistance mechanisms on the overall survival. Results: The whole group of 284 patients were included. The median age of recurrence and metastasis was 48 years old, 155 (54.6%) were hormone receptor (HR) positive and 129 (45.4%) were HR negative, 128 cases (45.1%) were premenopausal and 156 cases (54.9%) were postmenopausal, 277 cases (97.5%) had a score of 0-1 in ECoG PS and 7 cases (2.5%) had a score of more than 2 in the first diagnosis of relapse and metastasis. There were 103 cases (36.3%) in the primary drug resistance group and 181 cases (63.7%) in the secondary drug resistance group. The median overall survival time of the two groups was 24.9 months and 40.4 months, respectively, with statistical significance (P<0.001). Conclusion: Primary resistance to HER-2 is one of the factors of poor prognosis in HER-2 positive breast cancer, and its mechanism needs to be further explored.

Immunotherapy for microsatellite-instability-high advanced colorectal cancer

Microsatellite instability-high (MSI-H) colorectal cancer accounts for approximately 10%-15% of all colorectal cancer patients, while in metastatic diseases the MSI-H population accounts for only 5% of patients. Previous studies have shown that early-stage MSI-H colorectal cancer patients have a good prognosis, but those with advanced disease have a poor prognosis and are not sensitive to chemotherapy. The advent of PD-1 antibodies has significantly improved the prognosis and changed treatment landscape in this population, not only achieving good outcomes in late-line therapy, but also significantly outperforming traditional chemotherapy combined with targeted therapy in first-line therapy. How to overcome primary and secondary drug resistance is a key issue in improving the outcome of MSI-H metastatic colorectal cancer, and commonly used approaches include changing chemotherapy regimens, combining with other immunotherapies, combining with anti-angiogenesis, and local treatments (surgery, radiotherapy, or interventional therapy). It is worth noting that immunotherapy has certain lifelong or even lethal toxicity, and the indications for neoadjuvant immunotherapy must be evaluated with caution. Neoadjuvant immunotherapy in MSI-H advantaged population can achieve high rates of pathological complete remission (pCR) and clinical complete remission (cCR). Therefore, for MSI-H patients with a strong intention to preserve anal sphincter and a strict evaluation of cCR after neoadjuvant immunotherapy, the Watch-and-Wait strategy offers an opportunity to preserve sphincter function and improve long-term survival quality in a subset of mid-to-low rectal cancers. Research on adjuvant immunotherapy in the field of colorectal cancer is also in full swing, and the results are worth waiting for.

Primary drug resistance among Mycobacterium tuberculosis isolates from treatment naïve and new pulmonary tuberculosis patients in relation to their socio-economic status

BACKGROUND: Multidrug-resistant Tuberculosis (TB) has become an area of growing concern throughout the World, despite the global efforts in eliminating TB. Detection of primary drug resistance in treatment naïve patients, either due to spontaneous mutation or due to transmission of drug-resistant strains is an important indicator of the presence of drug-resistant strains in the community.OBJECTIVES: The objective is to estimate the prevalence of primary drug resistance in treatment naïve pulmonary TB patients and to identify the socio-economic class of the resistant population.MATERIALS AND METHODS: A total of 272 treatment naïve presumptive TB patients were enrolled in the study from September 2018 to December 2020. The samples were subjected to GeneXpert, for detecting the presence of Mycobacterium TB (MTB) along with Rifampicin (RIF) resistance detection. Phenotypic drug susceptibility testing (DST) was performed on all positive mycobacterial cultures using the 1% proportion method against first-line anti-tuberculous drugs. Socioeconomic status of the patients was also assessed based on updated Kuppuswamy Socioeconomic scale (2018).RESULTS: Of the 272 samples subjected to GeneXpert MTB/RIF assay, MTB was detected in 193 (71%) samples and RIF resistance (rpoB gene) was detected in 25 (9%) samples. Phenotypic DST detected multidrug-resistant (MDR) in 22 (8%) samples. Majority of the MDR patients (55%) were belonging to the upper lower (IV) class of Kuppuswamy socio-economic scale.CONCLUSION: High prevalence of MDR-TB among treatment naïve pulmonary TB patients was noted in patients belonging to Class IV of Kuppuswamy socio-economic scale.

MiR-21/Sonic Hedgehog (SHH)/PI3K/AKT Pathway is Associated with NSCLC of Primary EGFR-TKI Resistance

Background: Non-small cell lung cancer (NSCLC), caused by abnormal gene drive, may have primary drug resistance after treatment with tyrosine kinase inhibitors (EGFR-TKIs). Therefore, we explore whether the primary drug-resistant NSCLC treated with EGFR-TKI is related to the miR-21/Sonic Hedgehog (SHH)/PI3K/AKT pathway. Methods: The patients from our hospital who meet the AJCC TNM staging (7th edition) stage IIIB and stage IV NSCLC were selected in this case study. Thereafter, the treatment response of EGFR-TKIs was evaluated according to the solid tumor efficacy evaluation standard (version 1.1). The patients were divided into the EGFR-TKIs primary drug resistance group (EGFR-TKIs-Primary-R) and the EGFR-TKIs sensitive group (EGFR-TKIs-Primary-S). Apoptosis level and degree of fibrosis in patients’ tumor tissues were detected by the TUNEL assay and Masson staining, respectively. The levels of miR-21 and GLI1 were measured by qRT-PCR technique. The contents of E-cadherin and Snail were detected by IF method, and the degree of PI3K/AKT phosphorylation was measured using IHC technique. Results: Compared with the EGFR-TKIs-Primary-S group, the EGFR-TKIs-Primary-R group showed lower levels of apoptosis and tumor tissue fibrosis. The levels of miR-21, GLI1, Snail, p-PI3K and p-AKT increased, while the level of E-cadherin decreased. However, the levels of total protein PI3K and AKT remained the same. Conclusion: NSCLC of primary EGFR-TKI resistance was found to be related to miR-21/SHH, the process of epithelial to mesenchymal transition (EMT), and PI3K/AKT phosphorylation. The present study provides a reference for future research in drug resistance, and paves the way to discover new therapeutic gene targets to alleviate lung cancer drug resistance.

ДИНАМИКА ЛЕКАРСТВЕННОЙ УСТОЙЧИВОСТИ ВОЗБУДИТЕЛЕЙ ТУБЕРКУЛЁЗА ВО ВРЕМЯ ПАНДЕМИИ НОВОЙ КОРОНАВИРУСНОЙ ИНФЕКЦИИ В Г. ДУШАНБЕ: НЕОБХОДИМОСТЬ ПРИНЯТИЯ СРОЧНЫХ МЕР

Objective: To study the frequency and structure of primary and secondary drug resistance in M. tuberculosis (MTB) and risk factors for primary multidrug/rifampicin resistance (MDR/RR) in MTB before (Group I: 2018-2019) and during the COVID-19 pandemic (Group II: 2019-2020) in Dushanbe in patients with pulmonary tuberculosis (PTB). Methods: A cohort retrospective study included all patients with PTB tested for susceptibility to anti-tuberculosis drugs (ATD). Odds ratio (OR), 95% confidence interval (95% CI), and p-value were used to determine the significance of the association between frequency and drug susceptibility spectrum (DSS) in groups I and II; risk ratio (RR) was applied to assess a possible association between exposure and outcome. Results: The study included 559 newly diagnosed and 87 previously treated patients. Primary MDR/RR MTB was found in 21.1%, secondary – in 39.8% of patients: in group I, patients with primary MDR/RR MTB constituted 22.4%, secondary – 34.7%; in group II, the prevalence of secondary MDR/RR MTB was found to be three times higher than that of the primary resistance (OR=2.97; 95% CI=1.67-5.27, p&lt;0.001) due to a decrease in the prevalence of primary MDR/RR MTB (19.5%) and an increase in the secondary MDR/RR MTB (47.4%). There was a statistically significant increase in the frequency of primary drug resistance to fluoroquinolones in group II compared with group I: OR=2.58 for levofloxacin (p=0.003) and OR=2.31 for moxifloxacin (p=0.027). An increase in primary MDR/RR MTB was found among healthcare workers in group II (RR=3.21; 95% CI=1.50-6.89; p=0.05), which was statistically significant in patients with diabetes mellitus in both groups: group I (RR=1.83; p=0.035) and group II (OR=2.68; p&lt;0.001). Conclusion: The current high prevalence of primary and secondary MDR, the increase in monoresistance during the COVID-19 pandemic, and the association of MDR with employment in healthcare institutions raise concerns regarding the quality of implementation of tuberculosis (TB) infection control measures in Dushanbe. The increased frequency of resistance to fluoroquinolones requires immediate action to control their prescription. It is recommended to improve anti-TB standards among patients with diabetes mellitus. Keywords: Drug resistance, M. tuberculosis, risk factors for multidrug resistance, COVID-19.

The lncRNA CRNDE is regulated by E2F6 and sensitizes gastric cancer cells to chemotherapy by inhibiting autophagy.

Chemotherapy is an important treatment for gastric cancer (GC), but the primary and secondary drug resistance of tumours to chemotherapy seriously affects its curative effect. In recent years, the relationship between long noncoding RNAs (lncRNAs) and malignant tumours has received increasing attention. Based on accumulating evidence, lncRNAs are involved in the chemoresistance of GC, but the underlying mechanisms remain unclear. In this study, we identified the lncRNA colorectal neoplasia differentially expressed (CRNDE) as an important regulator of autophagy-associated chemoresistance in GC. Mechanistically, overexpression of CRNDE inhibits autophagy and induces apoptosis, thereby sensitizing GC cells to chemotherapy drugs. Moreover, E2F6, a classical transcriptional inhibitor, is confirmed to be upregulated in GC and represses the expression of CRNDE. The E2F6-CRNDE axis is clinically related to chemoresistant GC and poor outcomes in patients with advanced GC. Our findings suggest that the E2F6-CRNDE axis is a viable therapeutic target to protect against chemoresistance in GC.

Distinct Hypoxia-Related Gene Profiling Characterizes Clinicopathological Features and Immune Status of Mismatch Repair-Deficient Colon Cancer.

Despite dramatic responses to immune checkpoint inhibitors (ICIs) in patients with colon cancer (CC) harboring deficient mismatch repair (dMMR), more than half of these patients ultimately progress and experience primary or secondary drug resistance. There is no useful biomarker that is currently validated to accurately predict this resistance or stratify patients who may benefit from ICI-based immunotherapy. As hypoxic and acidic tumor microenvironment would greatly impair tumor-suppressing functions of tumor-infiltrating lymphocytes (TILs), we sought to explore distinct immunological phenotypes by analysis of the intratumoral hypoxia state using a well-established gene signature. Based on the Gene Expression Omnibus (GEO) (n = 88) and The Cancer Genome Atlas (TCGA) (n = 49) databases of patients with CC, we found that dMMR CC patients could be separated into normoxia subgroup (NS) and hypoxia subgroup (HS) with different levels of expression of hypoxia-related genes (lower in NS group and higher in HS group) using NMF package. Tumoral parenchyma in the HS group had a relatively lower level of immune cell infiltration, particularly CD8+ T cells and M1 macrophages than the NS group, and coincided with higher expression of immune checkpoint molecules and C-X-C motif chemokines, which might be associated with ICI resistance and prognosis. Furthermore, three genes, namely, MT1E, MT2A, and MAFF, were identified to be differentially expressed between NS and HS groups in both GEO and TCGA cohorts. Based on these genes, a prognostic model with stable and valuable predicting ability has been built for clinical application. In conclusion, the varying tumor-immune microenvironment (TIME) classified by hypoxia-related genes might be closely associated with different therapeutic responses of ICIs and prognosis of dMMR CC patients.