Molecular diagnosis and treatment of drug-resistant hepatitis B virus

Oral antiviral agents have been developed in the last two decades for the treatment of chronic hepatitis B(CHB).However,antiviral resistance remains an important challenge for long-term CHB therapy.All of the clinically available oral antiviral agents are nucleoside or nucleotide analogues that target the activity of viral reverse transcriptase(RT),and all are reported to have resistant mutations.Since the hepatitis B virus(HBV)RT,like other viral polymerases,lacks proofreading activity,the emergence of drug-resistance occurs readily under selective pressure from the administration of antiviral agents.The molecular diagnosis of drug-resistant HBV is based on sequence variations,and current diagnostic methods include sequencing,restriction fragment polymorphism analysis,and hybridization.Here,we will discuss the currently available molecular diagnosis tools,in vitro phenotypic assays for validation of drug-resistant HBV,and treatment options for drug-resistant HBV.

Expression of cyclooxygenase-2 mRNA in drug-sensitive cell and drug-resistant strains of ovarian cancer cell lines

Objective： To investigate the expression of cyclooxygenase-2 （COX-2） mRNA in drug-sensitive cell and drugresistant clones of ovarian cancer cell lines. Methods： RT-PCR and immunocytochemistry were used to investigate the expression of cyclooxygenase-2 in 3 clones drug-sensitive and 5 clones drug-resistant ovarian cancer cell. Results： Strong COX-2 mRNA expressions were detected in 3 clones of drug-sensitive cell and weak expressions were detected in 5 clones of drug-resistant cell. The protein expression of COX-2 in drug-sensitive cell was strongly positive reaction in immunocytochemistry stain and there was a weak positive reaction in 5 clones of drug-resistant cell. Conclusion： The expression of COX-2 mRNA in drug-sensitive cell strains is much higher than that in drugresistant strains of ovarian cancer cell lines, providing a basis of the chemoprevention for ovarian cancer.

Investigation of immune escape-associated mutations of hepatitis B virus in patients harboring hepatitis B virus drug-resistance mutations

It is unclear whether immune escape-associated mutations in the major hydrophilic region of hepatitis B virus surface antigen(HBsAg)are associated with nucleoside/nucleotide analog resistance.AIM To evaluate the association between immune escape-associated mutations and nucleoside/nucleotide analog resistance mutations.METHODS In total,19440 patients with chronic hepatitis B virus infection,who underwent resistance testing at the Fifth Medical Center of Chinese PLA General Hospital between July 2007 and December 2017,were enrolled.As determined by sequence analysis,6982 patients harbored a virus with resistance mutations and 12458 harbored a virus lacking resistance mutations.Phenotypic analyses were performed to evaluate HBsAg production,replication capacity,and drug-induced viral inhibition of patient-derived drug-resistant mutants with or without the coexistence of sA159V.RESULTS The rate of immune escape-associated mutation was significantly higher in 9 of the 39 analyzed mutation sites in patients with resistance mutations than in patients without resistance mutations.In particular,these mutations were sQ101H/K/R,sS114A/L/T,sT118A/K/M/R/S/V,sP120A/L/Q/S/T,sT/I126A/N/P/S,sM133I/L/T,sC137W/Y,sG145A/R,and sA159G/V.Among these,sA159V was detected in 1.95%(136/6982)of patients with resistance mutations and 1.08%(134/12,458)of patients lacking resistance mutations(P<0.05).The coexistence of sA159V with lamivudine(LAM)and entecavir(ETV)-resistance mutations in the same viral genome was identified during follow-up in some patients with drug resistance.HBsAg production was significantly lower and the replication capacity was significantly higher,without a significant difference in LAM/ETV susceptibility,in sA159V-containing LAM/ETV-resistant mutants than in their sA159V-lacking counterparts.CONCLUSION In summary,we observed a close link between the increase in certain immune escape-associated mutations and the development of resistance mutations.sA159V might increase the fitness of LAM/ETV-resistant mutants under environmental pressure in some cases.

Resistant mutants induced by adefovir dipivoxil in hepatitis B virus isolates

AIM: To investigate the loci of adefovir dipivoxil (ADV)-induced resistance in hepatitis B virus (HBV) isolates and optimize the management of ADV-treated patients.

Highly Selective Photodynamic Therapy with a Short Drug-Light Interval Using a Cytotoxic Photosensitizer Porphyrus Envelope for Drug-Resistant Prostate Cancer Cells

Background: Photodynamic therapy (PDT) is a less invasive cancer treatment using photochemical reactions induced by light irradiation to a photosensitizer (PS). Highly selective PDT with fast accumulation of the PS in target site might be a promising treatment option for drug-resistant prostate cancer facing high incidence rate of elderly men who have no effective treatment options and require a minimally invasive treatment. Hemagglutinating virus of Japan envelope (HVJ-E) allows selective and fast drug delivery to the drug-resistant prostate cancer cells via rapid cell membrane fusion. PS named porphyrus envelope (PE) has been developed by insertion of lipidated protoporphyrin IX (PpIX lipid) into HVJ-E. In this study, we investigated the optimal conditions for PE preparation and laser irradiation for highly selective PDT using PE with a short drug-light interval. Materials and Methods: Human hormon refractory prostate cancer cell line PC-3 and human normal prostate epithelial cell line PNT2 were cultured. PpIX lipid uptake and cytotoxicity of PDT in the cells incubated with PE for 10 min were evaluated by measuring fluorescence intensity and by using a cell counting reagent 24 h after PDT, respectively. Results: PpIX lipid uptake and cytotoxicity of PDT were increased with PpIX lipid concentration. Cytotoxicity of PDT using PE was more than 9 times as strong as that with PpIX lipid and PpIX induced by 5-aminolevulinic acid. Much stronger cytotoxicity was induced in PC-3 cells than PNT2 cells with the ratio of cell death rate for cancer to normal cells up to 4.64 ± 0.09. Conclusions: Fast PS delivery with HVJ-E allows highly selective PDT with a short drug-light interval. Therefore, PDT using PE has a potential to shorten treatment period and reduce side effects of PDT.

Competitive capacity of HIV-1 strains carrying M184I or Y181I drug-resistant mutations

Background Virus with nucleoside reverse transcriptase inhibitors （NRTIs） or nonnucleoside reverse transcriptase inhibitors （NNRTIs） resistant mutations show different evolution tendencies when the anti-viral therapies are interrupted. Understanding the replication fitness of drug-resistant virus is important for the study of the prevalence of drug-resistance For this purpose, we characterized the replication capacity of HIV-1 virus carrying lamivudine （3TC） or nevirapine （NVP） resistant mutations. Methods 3TC and NVP resistant variants were induced in vitro by selecting wild type virus in the presence of drugs. For the competitive replication assay, drug-resistant variants were cocultured with wild-type virus in the presence or absence of drugs. The ratios of the viral species were determined over time by using a real-time RT-PCR-based assay. Results 3TC-resistant （M184I mutation） and NVP-resistant （Y181I mutation） virus should be selected in vitro in two different ways. The competitive replication assay showed that the ratio of virus carrying a M184I mutation increased from 98.8%, while the wild type virus decreased to 1.2% after 4 passages in the presence of 3TC; the percentage of virus carrying the Y181I mutation increased to 90.5%, while wild type virus decreased to 9.5% in the presence of NVP. In the absence of drugs, the ratio of virus carrying the M184I mutation decreased to 5.3%, while wild type virus increased to 94.7%; the ratio of virus carrying Y181I increased to 75%, while wild type virus decreased to 25% after 4 passages. Conclusions The NVP-resistant virus is fitter than wild type virus even in the absence of NVP that may be the reason that NNRTIs-resistant virus is spreading quickly.

Establishment of drug-resistant HBV small-animal models by hydrodynamic injection

In antiviral therapy of hepatitis B virus(HBV)infection,drug resistance remains a huge obstacle to the long-term effectiveness of nucleoside/tide analogs(NAs).Primary resistance mutation(rtM204V)contributes to lamivudine(LAM)-resistance,and compensatory mutations(rtL180M and rtV173L)restore viral fitness and increase replication efficiency.The evaluation of new anti-viral agents against drug-resistant HBV is limited by the lack of available small-animal models.We established LAM-resistance HBV replication mice models based on clinical LAM-resistant HBV mutants.Double(rtM204VþrtL180M)or triple(rtM204VþrtL180MþrtV173L)lamivudine-resistant mutations were introduced into HBV expression vector,followed by hydrodynamic injection into tail vein of NOD/SCID mice.Viremia was detected on days 5,9,13 and 17 and liver HBV DNA was detected on day 17 after injection.The serum and liver HBV DNA levels in LAM-resistant model carrying triple mutations are the highest among the models.Two NAs,LAM and entecavir(ETV),were used to test the availability of the models.LAM and ETV inhibited viral replication on wild-type model.LAM was no longer effective on LAM-resistant models,but ETV retains a strong activity.Therefore,these models can be used to evaluate anti-viral agents against lamivudine-resistance,affording new opportunities to establish other drug-resistant HBV small-animal models.

Dynamic analysis of conversion from a drug-sensitivity strain to a drug ?resis tant st rain

drug-resistant strain is given to investigate how antibiotic usage may be optimized to preserve or restore antibiotic effectiveness. This novel theoretical framework could result in an optimal criterion on how to reduce the drug resistance to a reasonable range by using the antibiotic dressing strategy. The sufficient conditions of existence of order-1 periodic solution are obtained in view of the geometrical theory of the semi-continuous dynamical system and the qualitative properties of the corresp on ding continuous system. The stability of the order-1 periodic solution is proved by means of [H. J. Guo, L. S. Chen and X. Y. Song, Qualitative analysis of impulsive state feedback control to an algae-fish system with bistable property, Appl. Math. Comput. 271 (2015) 905-922]. Finally, our results are confirmed by means of numerical simulations.

Human mpox co-infection with advanced HIV-1 and XDR-TB in a MSM patient previously vaccinated against smallpox:A case report

Mpox is a zoonotic infectious disease caused by the mpox virus(MPXV).Historically,the majority of mpox cases have been documented in Central Africa.However,since May 2022,there has been a notable rise in reported cases from regions beyond Africa.Currently,over 110 countries spanning Europe,North America,South America,Asia,and other territories have reported mpox infections.This report details a case involving a patient who identifies as a man who has sex with men(MSM)and is concurrently infected with MPXV,human immunodeficiency virus type 1(HIV-1),Pneumocystis jiroveci,as well as extensively drug-resistant tuberculosis(XDR-TB).This patient had also received a vaccination for smallpox in the past.Additionally,we provide photographic documentation charting the progression of dermatological manifestations associated with mpox.This case highlights the significance of sexual intercourse as a crucial mode of transmission for mpox.The rapid and widespread dissemination of the MPXV across various regions,especially among MSM communities,underscores the importance of enhancing preventive education efforts targeted at high-risk populations.