Combination of betulinic acid and EGFR-TKIs exerts synergistic anti-tumor effects against wild-type EGFR NSCLC by inducing autophagy-related cell death via EGFR signaling pathway.

BACKGROUND: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of lung cancer patients with mutated EGFR. However, the efficacy of EGFR-TKIs in wild-type EGFR tumors has been shown to be marginal. Methods that can sensitize EGFR-TKIs to EGFR wild-type NSCLC remain rare. Hence, we determined whether combination treatment can maximize the therapeutic efficacy of EGFR-TKIs. METHODS: We established a focused drug screening system to investigate candidates for overcoming the intrinsic resistance of wild-type EGFR NSCLC to EGFR-TKIs. Molecular docking assays and western blotting were used to identify the binding mode and blocking effect of the candidate compounds. Proliferation assays, analyses of drug interactions, colony formation assays, flow cytometry and nude mice xenograft models were used to determine the effects and investigate the molecular mechanism of the combination treatment. RESULTS: Betulinic acid (BA) is effective at targeting EGFR and synergizes with EGFR-TKIs (gefitinib and osimertinib) preferentially against wild-type EGFR. BA showed inhibitory activity due to its interaction with the ATP-binding pocket of EGFR and dramatically enhanced the suppressive effects of EGFR-TKIs by blocking EGFR and modulating the EGFR-ATK-mTOR axis. Mechanistic studies revealed that the combination strategy activated EGFR-induced autophagic cell death and that the EGFR-AKT-mTOR signaling pathway was essential for completing autophagy and cell cycle arrest. Activation of the mTOR pathway or blockade of autophagy by specific chemical agents markedly attenuated the effect of cell cycle arrest. In vivo administration of the combination treatment caused marked tumor regression in the A549 xenografts. CONCLUSIONS: BA is a potential wild-type EGFR inhibitor that plays a critical role in sensitizing EGFR-TKI activity. BA combined with an EGFR-TKI effectively suppressed the proliferation and survival of intrinsically resistant lung cancer cells via the inhibition of EGFR as well as the induction of autophagy-related cell death, indicating that BA combined with an EGFR-TKI may be a potential therapeutic strategy for overcoming the primary resistance of wild-type EGFR-positive lung cancers.

[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.

Ambient air pollutants, diabetes and risk of newly diagnosed drug-resistant tuberculosis.

BACKGROUND: Drug-resistant tuberculosis (DR-TB), diabetes and exposure to air pollution are thought to be important threat to human health, but no studies have explored the effects of ambient air pollutants on DR-TB when adjusting diabetes status so far. METHODS: We performed a study among 3759 newly diagnosed TB cases with drug-susceptibility testing results, diabetes status, and individual air pollution data in Shandong from 2015 to 2019. Generalized linear mixed models (GLMM) including three models (Model 1: without covariates, Model 2: adjusted by diabetes status only, Model 3: with all covariates) were applied. RESULTS: Of 3759 TB patients enrolled, 716 (19.05%) were DR-TB, and 333 (8.86%) had diabetes. High exposure to O3 was associated with an increased risk of RFP-resistance (Model 2 or 3: odds ratio (OR) = 1.008, 95% confidence intervals (CI): 1.002-1.014), ethambutol-resistance (Model 3: OR = 1.015, 95%CI: 1.004-1.027) and any rifampicin+streptomycin resistance (Model 1,2,3: OR = 1.01, 95%CI: 1.002-1.018) at 90 days. In contrast, NO2 was associated with a reduced risk of DR-TB (Model 3: OR = 0.99, 95%CI: 0.981-0.999) and multidrug-resistant TB (MDR-TB) (Model 3: OR = 0.977, 95%CI: 0.96-0.994) at 360 days. Additionally, SO2 (Model 1, 2, 3: OR = 0.987, 95%CI: 0.977-0.998) showed a protective effect on MDR-TB at 90 days. PM2.5 (90 days, Model 2: OR = 0.991, 95%CI: 0.983-0.999), PM10 (360 days, Model 2: OR = 0.992, 95%CI: 0.985-0.999) had protective effects on any RFP+SM resistance. CONCLUSIONS: O3 contributed to an elevated risk of TB resistance but PM2.5, PM10, SO2, NO2 showed an inverse effect. Air pollutants may affect the development of drug resistance among TB cases by adjusting the status of diabetes.

Primary drug resistance of mycobacterium tuberculosis in Shandong, China, 2004-2018.

BACKGROUND: Primary drug-resistant tuberculosis (DR-TB) has contributed to a significant health and economic burden on a global scale, especially in China. we sought to estimate epidemiological characteristics of primary DR-TB in China from 2004 to 2018. METHODS: Eleven thousand four hundred sixty-seven newly diagnosed and 1981 retreated TB cases with drug susceptibility data were included. Chi-Square test for trends, linear regression, a joinpoint regression model and temporal trend in proportions of the different resistance patterns were carried out. RESULTS: The proportion of primary DR-TB and mono-resistant TB (MR-TB) in China had reduced by more than 12% since 2004, and were 21.38%, 13.35% in 2018 respectively. Among primary DR-TB cases (2173,18.95%), the percentage of multiresistant TB (MDR-TB, from 5.41 to 17.46%), male (from 77.03 to 84.13%), cavity (from 13.51 to 43.92%), rifampicin(RFP)-resistant TB (from 8.11 to 26.98%), streptomycin(SM)-resistant TB (from 50.00 to 71.43%) increased significantly (P < 0.05). On the contrary, the proportion of female, non-cavity, isoniazide(INH)-resistant TB (from 55.41 to 48.15%) and MR-TB (from 82.43 to 62.43%) decreased significant (P < 0.05). The primary drug resistance rate among female, cavity, smoking, drinking, 15 to 44 year-old TB subgroups increased by 0.16, 6.24, 20.95, 158.85, 31.49%, respectively. The percentage of primary DR-TB, RFP-resistant TB dropped significantly during 2004-2007 in Joinpoint regression model. CONCLUSION: The total rate of drug resistance among new TB cases showed a downward trend in Shandong, China, from 2004 to 2018. Primary drug resistance patterns were shifting from female, non-cavity, INH-resistant TB, and MR-TB groups to male, cavity, RFP/SM-resistant TB, and MDR-TB groups. Considering the rising drug resistance rate among some special population, future control of primary DR-TB in China may require an increased focus on female, cavity, smoking, drinking, or 15 to 44 year-old TB subgroups.

Prevalence and Risk Factors of Primary Drug-Resistant Tuberculosis in China.

OBJECTIVE: To investigate the prevalence of primary drug-resistant tuberculosis (TB) and associated risk factors in China. We also explored factors contributing to the transmission of multidrug-resistant tuberculosis (MDR-TB). METHODS: A total of 2794 representative, Mycobacterium tuberculosis isolates from treatment-naive patients were subjected to drug susceptibility testing, and risk factors for drug-resistant TB were analyzed. We also analyzed MDR-TB strain sublineages, drug-resistance-conferring mutations, and risk factors associated with clustered primary MDR strains. RESULTS: Among 2794 Mycobacterium tuberculosis isolates from treatment-naive patients, the prevalence of any resistance to first-line drugs was 33.2% and the prevalence of MDR-TB was 5.7%. We did not find any risk factors significantly associated with resistance to first-line drugs. The 93 primary MDR-TB isolates were classified into six sublineages, of which, 75 (80.6%) isolates were the RD105-deleted Beijing lineage. The largest sublineage included 65 (69.9%) isolates with concurrent deletions of RD105, RD207, and RD181. Twenty-nine (31.2%) primary MDR strains grouped in clusters; MDR isolates in clusters were more likely to have S531L rpoB mutation. CONCLUSION: This study indicates that primary drug-resistant TB and MDR-TB strains are prevalent in China, and multiple measures should be taken to address drug-resistant TB.

Limited increase in primary HIV-1C drug resistance mutations in treatment naïve individuals in Ethiopia.

Antiretroviral drug resistance is a major challenge for management and control of HIV-1 infection worldwide and particularly in resource limited countries. The frequency of primary drug resistance mutations (DRMs) and of naturally occurring polymorphisms was determined in 83 antiretroviral treatment (ART) naïve Ethiopian individuals infected with HIV-1, consecutively enrolled in 2010. In all individuals HIV-1C was found. The median (interquartile range) of CD4(+) T-cell count and viral load were 100 (49-201) cells/µl and 44,640 (12,553-134,664) copies/ml, respectively. Protease (PR) and reverse transcriptase (RT) genes of HIV-1 RNA were amplified and sequenced. The proportion of primary DRM to any drug class, using the World Health Organization mutation lists, was 7.2% (6/83), thus exceeding the WHO threshold limit of 5%. Three individuals (3.6%) had non-nucleoside reverse transcriptase inhibitor (NNRTI) mutations, two individuals (2.4%) had protease inhibitor mutations, and one (1.2%) had mutations associated with two drug classes (nucleoside reverse transcriptase inhibitor and NNRTI). In addition, the frequency of polymorphisms in the PR and RT genes was higher compared with previous studies in Ethiopian as well as worldwide isolates. Hence, genotypic drug resistance testing as part of routine management of individuals seems reasonable even in resource limited countries prior to treatment in order to allow proper choice of ART.

Cost-efficient HIV-1 drug resistance surveillance using multiplexed high-throughput amplicon sequencing: implications for use in low- and middle-income countries.

OBJECTIVES: Increased trends of primary drug resistance mutations (DRMs) among treatment-naive HIV-1-infected patients in low- and middle-income countries (LMICs) and the non-availability of pre-antiretroviral therapy (ART) genotypic resistance testing (GRT) may severely affect future therapeutic outcomes. The main objective of this study was therefore to develop a simplified, cost- and labour-efficient but high-throughput GRT protocol to be applied in the large-scale surveillance of DRMs in LMICs. PATIENTS AND METHODS: Ninety-six therapy-naive HIV-1-infected patients belonging to three cohorts were included: Indian patients followed at St John's Medical College Hospital, Bangalore, India (n = 49); East Africans (n = 21), who had migrated to Sweden; and Caucasians (n = 26) living in Sweden. GRT by population sequencing (GRT-PS) on individual plasma samples and GRT by next-generation sequencing (GRT-NGS) on equimolar multiplexed samples (n = 24) using Illumina MiSeq were performed. RESULTS: The multiplexing procedure was shown to be technically feasible and gave high-quality reads independent of whether HIV-1 subtype C or B was analysed. GRT-NGS detected all the DRMs found by GRT-PS. Additional clinically important low-abundance (<20% of the viral population) major DRMs (e.g. K101E, K103N, Y181C and M184V) were detected by GRT-NGS but not by GRT-PS. The frequency of low-abundance DRMs was higher among East African compared with Indian and Caucasian individuals. CONCLUSIONS: Our high-throughput next-generation sequencing with a multiplexed amplicon is a cost-efficient and promising approach for the large-scale surveillance of primary DRMs in LMICs where routine pre-ART GRT is not the standard of care. This strategy may be useful in optimizing future therapeutic regimens in those settings.

Short duration of lamivudine for the prevention of hepatitis B virus transmission in pregnancy: lack of potency and selection of resistance mutations.

This study sought to assess the antiviral efficacy of lamivudine (LMV) administered during third trimester to reduce maternal viraemia and to identify the emergence of LMV resistance. A prospective observational analysis was performed on 26 mothers with high viral load (>107 IU/mL). Twenty-one women received LMV (treated group) for an average of 53 days (range 22-88 days), and the remaining five formed the untreated control group. Serum samples from two time points were used to measure HBV DNA levels and antiviral drug resistance. The LMV-treated women achieved a median HBV DNA reduction of 2.6-log10 IU/mL. Although end-of-treatment (EOT) HBV DNA in four (18%) LMV-treated women remained at >10(7) IU/mL (± 0.5 log IU/mL), no mother-to-baby transmission was observed. In contrast, a baby from the untreated mother was HBsAg positive at 9 months postpartum. Four technologies were used for drug resistance testing. Only ultra-deep pyrosequencing (UDPS) was sufficiently sensitive to detect minor viral variants down to <1%. UDPS showed that LMV therapy resulted in increased viral quasispecies diversity and positive selection of HBV variants with reverse transcriptase amino acid substitutions at sites associated with primary LMV resistance (rtM204I/V and rtA181T) in four (19%) women. These viral variants were detected mostly at low frequencies (0.63-5.92%) at EOT, but one LMV-treated mother had an rtA181T variant that increased from 2.2% pretherapy to 25.59% at EOT. This mother was also infected with the vaccine escape variant (sG145R), which was inhibited by LMV treatment. LMV therapy during late pregnancy only reduced maternal viraemia moderately, and drug-resistant viral variants emerged.

[Low prevalence of hepatitis B virus primary drug resistance in Southern Spain]. / Baja prevalencia de resistencias primarias frente al virus de la hepatitis B en el sur de España.

INTRODUCTION: To know the prevalence of primary resistance in chronic hepatitis B naïve patients is essential to decide on the need of routine laboratory testing. PATIENTS AND METHODS: The genetic sequence of the HBV polymerase from 105naïve patients was analysed. RESULTS: rtV173L, a lamivudine compensatory mutation, was detected in two patients (1.9%), rtI233V in one patient, and another one carried the sG145R vaccine escape mutation. CONCLUSION: Our study shows that studying HBV resistance in naïve patients should not be recommended in the routine laboratory setting, for the time being.

Prevalence of Primary Drug Resistance Among Newly Diagnosed HIV-1-Infected Individuals in Hunan Province, China.

At present, research on the prevalence of primary drug resistance (PDR) in Hunan Province is limited. Therefore, we explored the current status of HIV-1 PDR in Hunan to provide a basis for antiretroviral therapy (ART) and a theoretical foundation for prevention and control of the HIV/AIDS epidemic. Three hundred seventy newly diagnosed HIV-1-infected individuals who had not received ART in Hunan province, China, were enrolled in the study. Plasma samples were collected, RNA was extracted, two rounds of gene amplification were carried out with the in-house method, and subtype analysis and drug resistance analysis were carried out with relevant software. We found that the most prevalent subtypes of HIV-1 in Hunan Province are CRF_01AE (126/359, 35.1%) and CRF07_BC (85/359, 23.7%). The PDR rate among newly diagnosed HIV/AIDS patients was 10.0% (36/359). Among them, the drug resistance rates of protease inhibitors, nucleotide reverse transcriptase inhibitors, non-nucleotide reverse transcriptase inhibitors, and integrase inhibitors were 0.3% (1/359), 3.3% (12/359), 8.36% (30/359), and 0.6% (2/359), respectively. The distribution of HIV-1 subtypes in Hunan Province is diverse and complex, and the PDR rate has exceeded the low-level warning line set by the World Health Organization (<5%). Therefore, we should conduct pretreatment drug resistance assays to determine the optimal primary ART so that patients can obtain better antiretroviral treatment outcomes and transmission of drug-resistant strains in the population can be blocked.

Computational drug repositioning for the identification of new agents to sensitize drug-resistant breast tumors across treatments and receptor subtypes.

Introduction: Drug resistance is a major obstacle in cancer treatment and can involve a variety of different factors. Identifying effective therapies for drug resistant tumors is integral for improving patient outcomes. Methods: In this study, we applied a computational drug repositioning approach to identify potential agents to sensitize primary drug resistant breast cancers. We extracted drug resistance profiles from the I-SPY 2 TRIAL, a neoadjuvant trial for early stage breast cancer, by comparing gene expression profiles of responder and non-responder patients stratified into treatments within HR/HER2 receptor subtypes, yielding 17 treatment-subtype pairs. We then used a rank-based pattern-matching strategy to identify compounds in the Connectivity Map, a database of cell line derived drug perturbation profiles, that can reverse these signatures in a breast cancer cell line. We hypothesize that reversing these drug resistance signatures will sensitize tumors to treatment and prolong survival. Results: We found that few individual genes are shared among the drug resistance profiles of different agents. At the pathway level, however, we found enrichment of immune pathways in the responders in 8 treatments within the HR+HER2+, HR+HER2-, and HR-HER2- receptor subtypes. We also found enrichment of estrogen response pathways in the non-responders in 10 treatments primarily within the hormone receptor positive subtypes. Although most of our drug predictions are unique to treatment arms and receptor subtypes, our drug repositioning pipeline identified the estrogen receptor antagonist fulvestrant as a compound that can potentially reverse resistance across 13/17 of the treatments and receptor subtypes including HR+ and triple negative. While fulvestrant showed limited efficacy when tested in a panel of 5 paclitaxel resistant breast cancer cell lines, it did increase drug response in combination with paclitaxel in HCC-1937, a triple negative breast cancer cell line. Conclusion: We applied a computational drug repurposing approach to identify potential agents to sensitize drug resistant breast cancers in the I-SPY 2 TRIAL. We identified fulvestrant as a potential drug hit and showed that it increased response in a paclitaxel-resistant triple negative breast cancer cell line, HCC-1937, when treated in combination with paclitaxel.

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

OBJECTIVES: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Trace the History of HIV and Predict Its Future through Genetic Sequences.

Traditional methods of quantifying epidemic spread are based on surveillance data. The most widely used surveillance data are normally incidence data from case reports and hospital records, which are normally susceptible to human error, and sometimes, they even can be seriously error-prone and incomplete when collected during a destructive epidemic. In this manuscript, we introduce a new method to study the spread of infectious disease. We gave an example of how to use this method to predict the virus spreading using the HIV gene sequences data of China. First, we applied Bayesian inference to gene sequences of two main subtypes of the HIV virus to infer the effective reproduction number (GRe(t)) to trace the history of HIV transmission. Second, a dynamic model was established to forecast the spread of HIV medication resistance in the future and also obtain its effective reproduction number (MRe(t)). Through fitting the two effective reproduction numbers obtained from the two separate ways above, some crucial parameters for the dynamic model were obtained. Simply raising the treatment rate has no impact on lowering the infection rate, according to the dynamics model research, but would instead increase the rate of medication resistance. The negative relationship between the prevalence of HIV and the survivorship of infected individuals following treatment may be to blame for this. Reducing the MSM population's number of sexual partners is a more efficient strategy to reduce transmission per the sensitivity analysis.

Proportion and trend of primary resistance among Multidrug resistant Tuberculosis patients in Ethiopia.

Background: Evidence based information on the proportion & trend of primary resistance among multidrug resistance (MDR) TB patients is important for designing effective strategies in the control of the disease. Methods: A retrospective record review of 348 MDR/RR-TB patients treated at All African Leprosy Rehabilitation & Training (ALERT) Center from January 2014- December 2018. Categorical variables were compared using Chi-square/Fisher exact test as appropriate. Trend analysis was done using chi-square & linear regression. Logistic regression analysis was done to determine the factors associated with primary MDR/RR TB. Adjusted Odds Ratio (AOR) with 95% CI and p value < 5% were used to report factors associated. Result: Proportion of primary resistance among MDR/RR TB patients was 25.9% with 95% CI 21.3-30.3%. The proportion increased form 9.7% in 2014 to 43.4% in 2018 at a yearly increasing rate of 9.27%. Contact history to TB patient & year of diagnosis 2017 and 2018 were significantly associated with primary resistance AOR (95% CI) & p value 4.15(1.75-9.84) p = 0.001, 3.87(1.44-10.39) p = 0.007, 3.43(1.20-9.84) p = 0.022 respectively. Conclusion: The study revealed a high proportion of primary resistance among MDR/RR TB during the study period with a linearly increasing fashion thus a need for due attention in the efforts to control MDR TB.

HIV-1 Drug Resistance Among Treatment-Naive Transgenders from India.

Transgenders (TGs) are highly affected by HIV with high prevalence of 3.14% in India. Since 2017, targeted preventive efforts have been initiated by the government and HIV-infected TGs are being provided the antiretroviral (ART) treatment. Information on the primary HIV drug resistance is crucial for appropriate treatment selection to curb further spread of HIV in this population. In this study, we analyzed HIV-1 pol gene sequences from 36 TGs for presence of drug resistance mutations. To our knowledge, this first study from India reports high-level primary drug resistance (13.8%) among the TG population. Mutations M184V, A98G, K103N, G190A, and Y318F associated with resistance to nucleoside reverse transcriptase inhibitor and non-nucleoside reverse transcriptase inhibitors were observed. All pol gene sequences revealed HIV-1 subtype C in all study TG. High-level HIV-1 drug resistance warrant nationwide larger studies on TGs to understand the level of primary ART drug resistance among this population.

Tumor Extrinsic Factors Mediate Primary T-DM1 Resistance in HER2-Positive Breast Cancer Cells.

To explore if the tumor microenvironment contributes to the primary resistance of HER2-positive breast cancer cells to T-DM1, we examined whether Matrigel, a basement membrane matrix that provides a three-dimensional (3D) cell culture condition, caused the primary resistance of HER2-positive, T-DM1-sensitive breast cancer cells (JIMT1 and SKBR-3 cells) to T-DM1. This is different from the conventional approach such that the cells are exposed with escalated doses of drug to establish a drug-resistant cell line. We found that these cells were able to grow and form spheroids on the Matrigel in the presence of T-DM1. We further explored the molecular mechanisms that enables these cells to be primarily resistant to T-DM1 and found that EGFR was activated in the spheroids, leading to an increased HER2 tyrosine phosphorylation. This in turn enhances cell growth signaling downstream of EGFR/HER2 in the spheroids. HER2 tyrosine phosphorylation promotes receptor internalization and degradation in the spheroids, which limits T-DM1 access to HER2 on the cell surface of spheroids. Blocking EGFR activity by erlotinib reduces HER2 tyrosine phosphorylation and enhances HER2 cell surface expression. This enables T-DM1 to gain access to HER2 on the cell surface, resumes cell sensitivity to T-DM1, and exhibits synergistic activity with T-DM1 to inhibit the formation of spheroids on Matrigel. The discovery described in this manuscript reveals a novel approach to investigate the primary resistance of HER2-positive breast cancer cells and provides an opportunity to develop a therapeutic strategy to overcome primary resistance to T-DM1 by combing T-DM1 therapy with kinase inhibitors of EGFR.

Pattern of primary tuberculosis drug resistance and associated risk factors at Dubai health authority in Dubai.

Background: The objective of this study is to determine the initial drug resistance pattern among new tuberculosis (TB) cases and assess the extent of association with human immunodeficiency virus (HIV) and diabetes mellitus (DM). Method: This is a retrospective analysis of 1116 clinical isolates were collected from patients who were newly diagnosed with TB at TB Laboratory between January 2016 and November 2019 and used for determining drug-resistance profiles against five first-line and five second-line anti-TB drugs; and the results were assessed the association between TB risk factors and primary drug resistance TB. Results: Of the 1116 newly diagnosed TB patients, 193 (17.3%) showed resistance to at least one or more of the first-line drugs by different patterns, 105 (9.4%) showed resistance to one drug, 38 (3.40%) showed polyresistance, 50 (4.5%) showed multidrug resistant (MDR), and one patient had extensively drug resistant. Mono-resistance to isoniazid (INH), STR, pyrazinamide, and rifampicin were seen in 40 (3.6%), 33 (2.95%), 29 (2.59%), and 3 (0.3%) of isolates, respectively. INH showed the highest percentage of resistance among the patients. Of 1116 newly diagnosed TB patients, 256 (22.9%) were TB-DM cases and 135 (12.9%) were TB-no DM cases. The rates of drug resistance-TB 46/1116 (4.12%), monoresistance 25 (2.24%), polyresistance 9 (0.8%), and MDR 12 (1.07%) among TB-DM group were higher than TB-no DM group. Conclusion: Our study confirms that resistance to INH was the most common phenomenon. We found that diabetes was identified as a risk factor of TB drug resistance. We did not find a significant association between HIV co-infection and TB drug-resistance.

Primary drug resistance among tuberculosis patients with diabetes mellitus: a retrospective study among 7223 cases in China.

BACKGROUND: Given the high burden of tuberculosis (TB) and diabetes mellitus (DM) in China and the worse outcome of TB-DM cases (refers to TB patients with diabetes), and drug-resistant tuberculosis cases (DR-TB), it is of great significance to explore the association between diabetes and primary DR-TB for TB elimination target in China. We assessed the clinical characteristics, drug-resistance profile, and increased risk of resistance among TB-DM patients across China from 2004 to 2017. METHOD: 7223 cases with drug-susceptibility data were collected from Shandong, China. Categorical baseline characteristics of new TB cases were compared by DM status using Fisher's exact or Pearson Chi-square test. Univariable analysis and multivariable logistic models were used to estimate the association between diabetes and different drug-resistance profiles and the risk factors of primary drug resistance among TB-DM cases. RESULT: Of 7223 newly diagnosed TB patients, 426 (5.90%) were TB-DM cases. TB-DM csaes were more likely to be older，accompanied by higher body mass index (BMI) and hypertension than TB-no DM cases (refers to TB patients without diabetes). The rates of DR-TB (21.83% vs 16.96%), polydrug resistant TB (PDR-TB, 6.10% vs 3.80%), isoniazid (INH)+streptomycin (SM)-resistant TB (4.93% vs 3.13%), and SM-resistant TB (16.20% vs 11.7%) among TB-DM group were higher than TB-no DM group, P<0.05. DM was significantly associated with any DR-TB (adjusted (aOR):1.30; 95% CI, 1.02-1.65), SM-related resistance (aOR: 1.43; 95% CI, 1.08-1.88), PDR-TB (OR: 1.57; 95% CI, 1.04-2.36; aOR: 1.59; 95% CI, 1.04-2.44), compared with pan-susceptible TB patients (P<0.05). CONCLUSION: Our study indicated that TB-DM groups had a higher proportion of drug resistance than TB groups, and diabetes was identified as a risk factor of total DR, PDR, SM resistance and INH+SM resistance among newly diagnosed TB cases. Good management of diabetes and TB infection screening program among DM patients might be necessary for improving TB control in China.