Current Perspectives on Letermovir and Maribavir for the Management of Cytomegalovirus Infection in Solid Organ Transplant Recipients.

Cytomegalovirus (CMV) infection is arguably the most important infectious complication that negatively affects the outcome of solid organ transplantation. For decades, CMV management after transplantation has relied on antiviral drugs that inhibit viral DNA polymerase (ganciclovir, foscarnet, and cidofovir). However, their use has been complicated by myelosuppression, nephrotoxicity, and selection of drug-resistant viruses. During the past few years, the therapeutic armamentarium for the management of CMV in solid organ transplant recipients has expanded with the approval of letermovir for CMV prophylaxis in high-risk CMV D+/R- kidney recipients, and maribavir for the treatment of refractory and resistant CMV infection. Both drugs offer significant improvement when compared to standard anti-CMV therapies; letermovir was as efficacious for CMV prevention, whereas maribavir was more effective in treating refractory and resistant CMV infections. Both letermovir and maribavir have favorable safety profiles compared to CMV DNA polymerase inhibitors, without the risk of neutropenia and leukopenia associated with ganciclovir and renal toxicities associated with foscarnet and cidofovir. Moreover, letermovir and maribavir are orally bioavailable, which allows convenient outpatient treatment. However, letermovir and maribavir have a significant drug interaction potential in solid organ transplant recipients, resulting in higher levels of calcineurin inhibitors (cyclosporine and tacrolimus) and mTOR inhibitors (sirolimus and everolimus). Both letermovir and maribavir are CMV-specific and do not have clinical efficacy against other herpes viruses. Thus, there is a need for additional antiviral drugs to prevent herpes simplex and other herpes viruses when clinically indicated. This article provides a comprehensive review of the clinical data supporting the use of letermovir and maribavir in clinical practice. The author provides perspectives on the role of these newly approved drugs in the current management landscape of CMV infection in solid organ transplantation.

Cytomegalovirus tracheobronchitis mimicking lung cancer progression in a patient with lung adenocarcinoma: A case report.

Cytomegalovirus (CMV) commonly infects immunocompromised individuals, such as cancer patients. We present a case involving a 60-year-old male with Stage 3A lung adenocarcinoma and chronic obstructive pulmonary disease (COPD) diagnosed with CMV tracheobronchitis, initially suspected as cancer progression. Treatment with ganciclovir led to partial improvement in symptoms of shortness of breath and cough, as well as bronchoscopic findings. However, due to ganciclovir-induced neutropenia, the therapy was switched to foscarnet. Distinguishing between cancer progression and infectious tracheobronchitis through physical examination and chest CT scans remains challenging. In lung cancer patients presenting with airway and bronchial narrowing along with ulcerative mucosal lesions, CMV infection should be considered. A bronchoscopic biopsy is crucial for accurate diagnosis and determining the appropriate treatment in these patients.

Serum ganciclovir drug exposure in children receiving standard ganciclovir dosing.

Intravenous ganciclovir (GCV) is used for the treatment of cytomegalovirus (CMV) infection in immunocompromised children. Although the therapeutic target for treatment is unclear, studies have shown a serum area under the concentration-time curve (AUC24h) ≥40 mg/L·h correlates with effective CMV prevention. This study aimed to externally validate existing GCV population pharmacokinetic (PopPK) models and develop a model if needed and evaluate the serum AUC24h achieved with standard GCV dosing and propose an optimized dosing strategy for immunocompromised children. Ganciclovir drug monitoring data from two pediatric hospitals were retrospectively collected, and published pediatric PopPK models were externally validated. The population AUC24h with standard GCV dosing (5 mg/kg twice daily) was calculated, and an optimized dosing strategy was determined using Monte Carlo simulations to achieve an AUC24h between 40 and 100 mg/L·h. Overall, 161 samples from 23 children with a median (range) age of 9.0 years (0.4-17.0) and weight of 28.2 kg (5.6-73.3) were analyzed. Transferability of published pediatric PopPK models was limited. Thus, a one-compartment model with first-order absorption and elimination with weight and serum creatinine as covariates was developed. The median (5th-95th percentiles) steady state AUC24h with standard dosing was 38.3 mg/L·h (24.8-329.2) with 13 children having an AUC24h <40 mg/L·h, particularly those aged <4 years (8/13). An optimized simulated GCV dosing regimen, ranging from 2 to 13 mg/kg twice daily for children with normal renal function, achieved 61%-78% probability of target attainment. Standard GCV dosing likely results in inadequate drug exposure in more than half of the children, particularly those aged <4 years. An optimized dosing regimen has been proposed for clinical validation.

Management of cytomegalovirus infection after liver transplantation.

Cytomegalovirus (CMV) infection is one of the primary causes of morbidity and mortality following liver transplantation (LT). Based on current worldwide guidelines, the most effective strategies for avoiding post-transplant CMV infection are antiviral prophylaxis and pre-emptive treatment. CMV- IgG serology is the established technique for pretransplant screening of both donors and recipients. The clinical presentation of CMV infection and disease exhibits variability, prompting clinicians to consistently consider this possibility, particularly within the first year post-transplantation or subsequent to heightened immunosuppression. At annual symposia to discuss CMV prevention and how treatment outcomes can be improved, evidence on the incorporation of immune functional tests into clinical practice is presented, and the results of studies with new antiviral treatments are evaluated. Although there are ongoing studies on the use of letermovir and maribavir in solid organ transplantation, a consensus reflected in the guidelines has not been formed. Determining the most appropriate strategy at the individual level appears to be the key to enhancing outcomes. Although prevention strategies reduce the risk of CMV disease, the disease can still occur in up to 50% of high-risk patients. A balance between the risk of infection and disease development and the use of immunosuppressants must be considered when talking about the proper management of CMV in solid organ transplant recipients. The objective of this study was to establish a comprehensive framework for the management of CMV in patients who have had LT.

Long-Term Follow-up of Patients With Cytomegalovirus Retinitis Treated With a Ganciclovir Implant.

Purpose: To assess the long-term safety and clinical outcomes of a ganciclovir intravitreal implant in patients with cytomegalovirus (CMV) retinitis. Methods: A retrospective study was performed of patients with CMV retinitis treated with a ganciclovir intravitreal implant. Results: The study included 13 patients (16 eyes) previously treated with a ganciclovir intravitreal implant. The mean time since the last implant placement was 21.3 years and the mean total duration of follow-up, 22.7 years. Visual acuity (VA) ranged from 20/25 to light perception, with 56% of eyes maintaining a VA of 20/60 or better at the most recent follow-up examination. Common ocular complications included epiretinal membrane (38%), macular fibrosis/scarring (25%), retinal detachment (RD) (25%), implant dislocation (25%), and immune reactivation uveitis (19%). Intraocular surgery was required in 10 eyes (63%), with the most frequent being cataract extraction (31%), pars plana vitrectomy (PPV) for implant removal (19%), and PPV for RD (13%). Conclusions: Results show the long-term safety of the ganciclovir intravitreal implant despite its residual inactive inert shell. Complication rates are consistent with those expected from infectious sequelae.

Considerable differences in management of cytomegalovirus infection in patients with biliary atresia.

Objectives: Patients with biliary atresia (BA) and ongoing cytomegalovirus (CMV) infection may have poorer outcomes after Kasai portoenterostomy than uninfected patients. Still, there is no consensus on the usefulness of viral testing and antiviral treatment (AVT). This study aims to explore the need for future research on AVT for CMV infection by assessing how CMV infection in BA patients is managed in different centers. Methods: An online questionnaire with 10 questions was offered to participants at an international congress on BA, organized in collaboration with the European Reference Network for rare liver diseases in 2022. Answers to questions were either dichotomic or multiple choices of different numeric intervals. Ongoing CMV infection was defined by detecting cytomegalovirus-immunoglobulin M (CMV-IgM) in serum or cytomegalovirus-deoxyribonucleic acid (CMV-DNA) by polymerase chain reaction in blood or urine. Results: There were 43 respondents from 36 centers in 26 countries. The total number of BA patients per year was between 208 and 380 from centers with 0-5 to >20 BA patients yearly (median 6-10). CMV infection was tested in 27 centers (75%), of which 18 (67%) use AVT. The rate of CMV infection varied between 0%-5% and 40%-50% (median 5%-10%). Willingness to treat the infection did not differ between centers with low and high rates of CMV infection. Conclusions: Most centers test for CMV infection, and a considerable proportion use AVT despite the lack of evidence of its benefits. A future randomized study on treating CMV infection in BA patients is necessary and feasible.

HerpesDRG: a comprehensive resource for human herpesvirus antiviral drug resistance genotyping.

The prevention and treatment of many herpesvirus associated diseases is based on the utilization of antiviral therapies, however therapeutic success is limited by the development of drug resistance. Currently no single database cataloguing resistance mutations exists, which hampers the use of sequence data for patient management. We therefore developed HerpesDRG, a drug resistance mutation database that incorporates all the known resistance genes and current treatment options, built from a systematic review of available genotype to phenotype literature. The database is released along with an R package that provides a simple approach to resistance variant annotation and clinical implication analysis from common sanger and next generation sequencing data. This represents the first openly available and community maintainable database of drug resistance mutations for the human herpesviruses (HHV), developed for the community of researchers and clinicians tackling HHV drug resistance.

Assessment of Dried Serum Spots (DSS) and Volumetric-Absorptive Microsampling (VAMS) Techniques in Therapeutic Drug Monitoring of (Val)Ganciclovir-Comparative Study in Analytical and Clinical Practice.

Ganciclovir (GCV) and its prodrug valganciclovir (VGCV) are antiviral medications primarily used to treat infections caused by cytomegalovirus (CMV), particularly in immunocompromised individuals such as solid organ transplant (SOT) recipients. Therapy with GCV is associated with significant side effects, including bone marrow suppression. Therefore, therapeutic drug monitoring (TDM) is mandatory for an appropriate balance between subtherapeutic and toxic drug levels. This study aimed to develop and validate three novel methods based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for GCV determination in serum (reference methodology), dried serum spots (DSS), and VAMS-Mitra™ devices. The methods were optimized and validated in the 0.1-25 mg/L calibration range. The obtained results fulfilled the EMA acceptance criteria for bioanalytical method validation. Assessment of DSS and VAMS techniques extended GCV stability to serum for up to a minimum of 49 days (at room temperature, with desiccant). Developed methods were effectively evaluated using 80 clinical serum samples from pediatric renal transplant recipients. Obtained samples were used for DSS, and dried serum VAMS samples were manually generated in the laboratory. The results of GCV determination using serum-, DSS- and VAMS-LC-MS/MS methods were compared using regression analysis and bias evaluation. The conducted statistical analysis confirmed the interchangeability between developed assays. The DSS and VAMS samples are more accessible and stable during storage, transport and shipment than classic serum samples.

Effects of ganciclovir combined with recombinant human interferon-α on clinical efficacy and immune function in children with infectious mononucleosis.

Objective: To evaluate the effects of ganciclovir combined with recombinant human interferon on clinical efficacy and immune function of children with infectious mononucleosis(IM). Methods: This was a retrospective study. Children (n=120) with IM hospitalized in Beijing Children's Hospital Affiliated to Capital Medical University Baoding Hospital from January 2020 to January 2022 were selected and randomly divided into study group and control group((n=60). Patients in the control group were treated with ganciclovir by intravenous infusion, and patients in the study group were given ganciclovir+recombinant human interferon-α1b. The time for eliminating clinical symptoms, the levels of inflammatory cytokines, immune function condition and T-lymphocyte subsets between the two groups were compared and analyzed. Results: After treatment, the time for body temperature returned to normal, time for recovery from cervical lymphadenopathy, time for recovery from hepatosplenomegaly and time for disappearance of angina and oral mucosal congestion in the study group were significantly shorter than those in the control group(p= 0.00); after treatment, the levels of TNF-a and IL-6 in the study group were significantly lower than those in the control group; the indexes of CD3+ and CD8+ in the study group were significantly lower than those in the control group; after treatment, the levels of CD4+ and CD4+/CD8+ in the study group were significantly higher than those in the control group. Conclusion: Ranciclovir combined with recombinant human interferon-α1b, rapid improvements of clinical symptoms, significantly decreased inflammatory cytokines, improved T-lymphocyte function and no significant increase in adverse drug reactions were found in children with IM.

The pharmacokinetics of ganciclovir during prolonged intermittent kidney replacement therapy in a cardiac transplant recipient.

Ganciclovir, a guanine analogue, is used intravenously (IV) first-line for the prophylaxis and treatment of cytomegalovirus (CMV) infection in solid organ transplant recipients. The pharmacokinetics (PK) of ganciclovir are highly variable, with myelosuppression occurring at high concentrations. Ganciclovir is primarily renally excreted as the parent compound, and clearance is significantly reduced in renal impairment. Acute kidney injury (AKI) is a common post-operative complication of cardiac transplantation, reducing the clearance of ganciclovir. In the intensive care unit (ICU), AKI is often managed by kidney replacement therapy (KRT). One form of KRT, prolonged intermittent kidney replacement therapy (PIKRT) is increasingly used for cost and flexibility advantages. Ganciclovir dosing recommendations are available for varying degrees of renal impairment and KRT, except for PIKRT. In this case of cardiac transplantation, complicated by anuric AKI, a ganciclovir dose of 2.0-2.5 mg/kg of adjusted body weight given after each PIKRT session was demonstrated to achieve PK targets.

Cytomegalovirus retinitis with panretinal occlusive vasculopathy concealed by hypertensive uveitis: a case report.

Cytomegalovirus (CMV) retinitis is a rare disease, and overlapping manifestations involving the anterior segment are extremely uncommon. We report a patient who initially presented with persistent corneal edema and was later diagnosed with CMV retinitis. A 72-year-old man with uncontrolled intraocular pressure (IOP) in his right eye visited a tertiary hospital. At initial presentation, the IOP was 36 mmHg and the fundus was not clear due to corneal edema. Spectral domain optical coherence tomography revealed paracentral acute middle maculopathy (PAMM). Panretinal obstructive vasculopathy was observed on ultra-widefield fluorescein angiography. Three weeks later, trabeculectomy was performed to resolve the persistently high IOP. Once corneal edema improved, a white patch-like peripheral lesion and silver wire-like retinal vasculature were observed. Polymerase chain reaction of the aqueous humor was positive for CMV. Oral valganciclovir and intravitreal ganciclovir were administered as antiviral therapies. Despite treatment for 4 months, the final visual acuity was no light perception, with persistent corneal edema and neovascularization of the iris. We describe a rare case of the simultaneous occurrence of hypertensive uveitis and CMV retinitis. The presence of PAMM could be an initial identifiable sign of CMV retinitis, even in the presence of media opacity.

Pharmacokinetics of ganciclovir eye drops: a comparative study of solutions prepared from ganciclovir for intravenous infusion and ganciclovir gel.

PURPOSE: To evaluate the pharmacokinetics of ganciclovir eye drops by comparing solutions prepared from ganciclovir for intravenous infusion and ganciclovir gel and to assess the impact of systemic administration on drug levels in ocular tissues and serum. STUDY DESIGN: Experimental study design. METHODS: Ganciclovir solutions (0.5% and 1.0%) prepared by diluting DENOSINE ® IV Infusion in saline and 0.15% ganciclovir gel (Virgan®) were topically administered in rabbit eyes, with and without concomitant systemic administration of ganciclovir. The concentrations of ganciclovir in the corneal epithelium, stroma, and endothelium, aqueous humor; and blood plasma were analyzed by high-performance liquid chromatography (HPLC). RESULTS: The ganciclovir solutions (0.5% and 1.0%) maintained therapeutic ganciclovir levels in the corneal endothelium above the effective dose required for 50% inhibition (ED50) up to 6 h, albeit with a swift decline thereafter. The 0.15% ganciclovir gel maintained higher therapeutic concentrations in the corneal endothelium for up to 12 h, exceeding the ED50. Serum concentrations of ganciclovir were significantly elevated in the groups receiving combined systemic administration. CONCLUSION: Topical application of 0.15% ganciclovir gel maintained high endothelial concentrations, well above the therapeutic threshold, with or without systemic administration. Furthermore, the observed increase in ganciclovir levels within the plasma and aqueous humor following systemic administration posits it as a viable strategy for severe cases of cytomegalovirus corneal endotheliitis or those inadequately managed by local treatments alone.

Cytomegalovirus Ileitis in a Patient With Post-severe Trauma: A Case Report.

BACKGROUND/AIM: The mortality rate for alimentary tract hemorrhage remains high due to a variety of contributing factors. In this report, we present a case of post-severe trauma patient with life-threatening gastrointestinal bleeding caused by cytomegalovirus (CMV)-induced damage to the terminal ileum. CASE REPORT: A 76-year-old female with a history of hypertension and gastrointestinal bleeding developed CMV ileitis post-severe trauma. Despite negative CMV IgM antibodies, PCR testing confirmed CMV infection in the biopsy tissue. Histopathological examination revealed viral inclusion bodies, with immunohistochemistry confirming CMV presence. RESULTS: Intravenous ganciclovir effectively managed symptoms and halted bleeding. CMV ileitis, typically seen in immunocompromised states, may occur sporadically in immunocompetent individuals, including post-orthopedic surgery patients. The exact mechanism remains unclear, possibly related to surgical stress. Diagnosis relies on histopathology and immunohistochemistry. CONCLUSION: Early recognition and treatment are vital for optimal outcomes, emphasizing the need for awareness among orthopedic surgeons regarding CMV as a potential cause of postoperative complications.

Application of machine-learning models to predict the ganciclovir and valganciclovir exposure in children using a limited sampling strategy.

Intravenous ganciclovir and oral valganciclovir display significant variability in ganciclovir pharmacokinetics, particularly in children. Therapeutic drug monitoring currently relies on the area under the concentration-time (AUC). Machine-learning (ML) algorithms represent an interesting alternative to Maximum-a-Posteriori Bayesian-estimators for AUC estimation. The goal of our study was to develop and validate an ML-based limited sampling strategy (LSS) approach to determine ganciclovir AUC0-24 after administration of either intravenous ganciclovir or oral valganciclovir in children. Pharmacokinetic parameters from four published population pharmacokinetic models, in addition to the World Health Organization growth curve for children, were used in the mrgsolve R package to simulate 10,800 pharmacokinetic profiles of children. Different ML algorithms were trained to predict AUC0-24 based on different combinations of two or three samples. Performances were evaluated in a simulated test set and in an external data set of real patients. The best estimation performances in the test set were obtained with the Xgboost algorithm using a 2 and 6 hours post dose LSS for oral valganciclovir (relative mean prediction error [rMPE] = 0.4% and relative root mean square error [rRMSE] = 5.7%) and 0 and 2 hours post dose LSS for intravenous ganciclovir (rMPE = 0.9% and rRMSE = 12.4%). In the external data set, the performance based on these two sample LSS was acceptable: rMPE = 0.2% and rRMSE = 16.5% for valganciclovir and rMPE = -9.7% and rRMSE = 17.2% for intravenous ganciclovir. The Xgboost algorithm developed resulted in a clinically relevant individual estimation using only two blood samples. This will improve the implementation of AUC-targeted ganciclovir therapeutic drug monitoring in children.

Therapeutic Myths in Solid Organ Transplantation Infectious Diseases.

Infection management in solid organ transplantation poses unique challenges, with a diverse array of potential pathogens and associated antimicrobial therapies. With limited high-quality randomized clinical trials to direct optimal care, therapeutic "myths" may propagate and contribute to suboptimal or excessive antimicrobial use. We discuss 6 therapeutic myths with particular relevance to solid organ transplantation and provide recommendations for infectious diseases clinicians involved in the care of this high-risk population.

Treatment outcomes in cytomegalovirus anterior uveitis.

This retrospective cohort study investigated patients with cytomegalovirus anterior uveitis (CMV AU) and compared treatment outcomes between regional and systemic antiviral therapies. Treatment modalities included topical (2% ganciclovir [GCV] eye drops or 0.2% GCV eye gel) and systemic (intravenous GCV or oral valganciclovir) groups. The comparison parameters included response rates, time to response, recurrence rates, time to recurrence, and complications. Forty-four patients (54.5% male) with a mean age of 56 ± 9.87 years were enrolled, with 31 eyes in the topical group and 13 eyes in the systemic group. The median response time was significantly slower in the topical group (63 days [IQR 28-112]) compared to the systemic group (28 days [IQR 24-59]) (p = 0.04). Treatment response rates were 87.1% (27/31) in the topical group and 100% (13/13) in the systemic group (p = 0.30), while recurrence rates were 37% (10/27) and 69.2% (9/13) (p = 0.056), with a median time to recurrence of 483 days [IQR 145-1388] and 392 days [IQR 203.5-1907.5] (p = 0.20), respectively. In conclusion, both topical and systemic GCV treatments demonstrated favorable outcomes for CMV AU. Systemic GCV showed rapid control of intraocular inflammation.

Contribution of Adsorption and Hematocrit Levels to Ganciclovir Clearance in an in Vitro Continuous Hemodiafiltration Model.

Estimation of the continuous hemodiafiltration (CHDF) clearance (CLCHDF) of ganciclovir (GCV) is crucial for achieving efficient treatment outcomes. Here, we aimed to clarify the contribution of diafiltration, adsorption, and hematocrit level to the CLCHDF of GCV in an in vitro CHDF model using three membranes: polyacrylonitrile and sodium methallyl sulfonate copolymer coated with polyethylenimine (AN69ST); polymethylmethacrylate (PMMA); and polysulfone (PS). In vitro CHDF was performed with effluent flow rates (Qe) of 800, 1500, and 3000 mL/h. The initial GCV concentration was 10 µg/mL while that of human serum albumin (HSA) was 0 or 5 g/dL. The CLCHDF, diafiltration rates, and adsorption rates were calculated. The whole blood-to-plasma ratio (R) of GCV for a hematocrit of 0.1 to 0.5 was determined using blood samples with 0.5 to 100 µg/mL of GCV. The in vitro CHDF experiment using AN69ST, PMMA, and PS membranes showed that the total CLCHDF values were almost the same as the Qe and not influenced by the HSA concentration. The diafiltration rate exceeded 88.1 ± 2.8% while the adsorption rate was lower than 9.4 ± 9.4% in all conditions. The R value was 1.89 ± 0.11 and was similar at all hematocrit levels and GCV concentrations. In conclusion, diafiltration mainly contributes to the CLCHDF of GCV, rather than adsorption. Hematocrit levels might not affect the relationship between the plasma and blood CLCHDF of GCV, and the CLCHDF of GCV can be estimated from the Qe and R, at least in vitro.

Advancing Green Chemistry in Antiviral Therapeutics: A Comprehensive Review.

Cytomegalovirus (CMV) is a prevalent virus across the world that belongs to the family Herpesviridae but remains dormant in the body unless the immune system is compromised. In addition, when the bacterium is compromised without any health risks, the infection spreads from one person to another person through body fluids, such as saliva, blood, etc. Ganciclovir is an anti- viral medication used in treating viral infections, especially in the treatment of CMV in people with acquired immune deficiency syndrome and immunity at risk. The quality control of ganciclovir in industries is carried out by using anti-green solvents in large volumes; these solvents are not safe in consideration of environmental factors and analysts. Also, the waste generation by these solvents causes hazardous effects on the environment. Further, using 12 green analytical chemistry principles promotes the awareness of analytical judgments among the research groups. It is a revolutionary step in the analytical field to enhance the safety of the environment, and analysts, apart from safety, help to control waste production and conserve energy-reducing occupational hazards. Many works have been carried out for the quality control of ganciclovir using different solvents, such as acetonitrile, methanol, etc. Despite this, there are no existing methods with green solvents or procedures to reduce energy and waste generation. Therefore, the purpose of this review is to understand the drug profile of ganciclovir and the methods developed.

Challenges for the improvement of valganciclovir prophylaxis in solid organ transplantation and the possible role of therapeutic drug monitoring in adults.

Cytomegalovirus (CMV) infection frequently occurs after solid organ transplantation and is associated with an increased morbidity and mortality. Fortunately, the development of valganciclovir prophylaxis has lowered the incidence of CMV infection and its complications in immunosuppressed solid organ transplant recipients. However, breakthrough infections during valganciclovir prophylaxis and late CMV infection after cessation of valganciclovir prophylaxis still occur with the current prophylactic strategy. Additionally, valganciclovir resistance has emerged among CMV strains, which complicates the treatment of CMV infections. Furthermore, the use of valganciclovir is associated with myelotoxicity, which can lead to the premature withdrawal of prophylaxis. It is important to address these current issues in order to improve the standard care after solid organ transplantation. This paper will therefore discuss the clinical practice of valganciclovir prophylaxis, elaborate on its issues and suggest how to improve the current prophylactic strategy with a possible role for therapeutic drug monitoring.

The Histogenetic Origin of Malignant Cells Predicts Their Susceptibility towards Synthetic Lethality Utilizing the TK.007 System.

BACKGROUND: Remarkable differences exist in the outcome of systemic cancer therapies. Lymphomas and leukemias generally respond well to systemic chemotherapies, while solid cancers often fail. We engineered different human cancer cells lines to uniformly express a modified herpes simplex virus thymidine kinase TK.007 as a suicide gene when ganciclovir (GCV) is applied, thus in theory achieving a similar response in all cell lines. METHODS: Fifteen different cell lines were engineered to express the TK.007 gene. XTT-cell proliferation assays were performed and the IC50-values were calculated. Functional kinome profiling, mRNA sequencing, and bottom-up proteomics analysis with Ingenuity pathway analysis were performed. RESULTS: GCV potency varied among cell lines, with lymphoma and leukemia cells showing higher susceptibility than solid cancer cells. Functional kinome profiling implies a contribution of the SRC family kinases and decreased overall kinase activity. mRNA sequencing highlighted alterations in the MAPK pathways and bottom-up proteomics showed differences in apoptotic and epithelial junction signaling proteins. CONCLUSIONS: The histogenetic origin of cells influenced the susceptibility of human malignant cells towards cytotoxic agents with leukemias and lymphomas being more sensitive than solid cancer cells.