Social Anxiety Symptoms in Adolescents and Young Adults Recently Diagnosed with Cancer.

Purpose: Social anxiety disorder (SAD) remains an understudied potential link between the cancer experience and adolescent and young adult (AYA) cancer survivors' poor psychosocial outcomes. We investigated the frequency and duration of, as well as factors associated with, symptoms of SAD among AYAs with cancer. Methods: This longitudinal, mixed-methods study involved online surveys (including a validated screening tool for SAD) at recruitment and 6 months later, and a structured clinical interview. Results: Twenty-eight AYAs (aged 12-30 years, <1-year postdiagnosis, 50% male) completed the first survey (M = 6 months postdiagnosis). About 32% reported clinically significant SAD symptoms. Fourteen completed the follow-up survey (M = 12 months postdiagnosis), of which 9 (62%) reported persistent or worse symptoms of SAD significantly associated with emotional distress, physical appearance concerns, negative social cognitions, and depression. Conclusion: A subset of AYAs with cancer may experience clinically significant SAD symptoms that can affect their psychosocial well-being. Further work on how to best identify and support AYAs with SAD is needed.

Long-term nivolumab treatment possibly associated with aseptic meningitis.

Nivolumab is a programmed death-1 receptor blocker within the family of medications called immune checkpoint inhibitors (ICIs). Although generally well tolerated, cases of immune-related adverse events (irAEs) have been reported. We present a case of a man being treated with nivolumab for renal cell carcinoma who presented to the emergency department with problems of headache, fever and disorientation. After extensive evaluation, a diagnosis of immunotherapy-induced aseptic meningitis was considered more probable than infectious. Due to stable clinical status, no treatment was initiated, and the patient's condition improved spontaneously. The patient was discharged home. To date, only a handful of prior cases of nivolumab-induced meningitis have been reported. Our case demonstrates that irAEs can occur years after the initiation of ICIs. This was a milder presentation of a neurological irAE that resolved spontaneously with watchful waiting, showing that irAEs are likely an evolving spectrum of disease for which clinicians should be aware.

EMPOWERED trial: protocol for a randomised control trial of digitally supported, highly personalised and measurement-based care to improve functional outcomes in young people with mood disorders.

OBJECTIVES: Many adolescents and young adults with emerging mood disorders do not achieve substantial improvements in education, employment, or social function after receiving standard youth mental health care. We have developed a new model of care referred to as 'highly personalised and measurement-based care' (HP&MBC). HP&MBC involves repeated assessment of multidimensional domains of morbidity to enable continuous and personalised clinical decision-making. Although measurement-based care is common in medical disease management, it is not a standard practice in mental health. This clinical effectiveness trial tests whether HP&MBC, supported by continuous digital feedback, delivers better functional improvements than standard care and digital support. METHOD AND ANALYSIS: This controlled implementation trial is a PROBE study (Prospective, Randomised, Open, Blinded End-point) that comprises a multisite 24-month, assessor-blinded, follow-up study of 1500 individuals aged 15-25 years who present for mental health treatment. Eligible participants will be individually randomised (1:1) to 12 months of HP&MBC or standardised clinical care. The primary outcome measure is social and occupational functioning 12 months after trial entry, assessed by the Social and Occupational Functioning Assessment Scale. Clinical and social outcomes for all participants will be monitored for a further 12 months after cessation of active care. ETHICS AND DISSEMINATION: This clinical trial has been reviewed and approved by the Human Research Ethics Committee of the Sydney Local Health District (HREC Approval Number: X22-0042 & 2022/ETH00725, Protocol ID: BMC-YMH-003-2018, protocol version: V.3, 03/08/2022). Research findings will be disseminated through peer-reviewed journals, presentations at scientific conferences, and to user and advocacy groups. Participant data will be deidentified. TRIAL REGISTRATION NUMBER: ACTRN12622000882729.

Comparative admission rates and infection severity of COVID-19 among unvaccinated and vaccinated patients.

Vaccination efforts have limited the burden of the pandemic caused by the coronavirus disease 2019 (COVID-19) with substantial evidence showing reduced hospitalization rates among vaccinated populations. However, few studies have explored correlations between vaccination status and inpatient COVID-19 outcomes. This observational case-control study involved a retrospective chart review of adult patients hospitalized for COVID-19 infection at a medium-sized hospital in Central Michigan between May 1, 2021 and September 30, 2021. Unadjusted analyses involved t-tests and chi-square tests followed by adjusted analyses using binary logistic and linear regression models. Of the 192 screened patients, 171 subjects met the inclusion criteria. Vaccinated patients were significantly older (71.09 vs 57.45, p < 0.001), more likely to identify as white (89.4% vs 66.9%, p = 0.026), and had a lower baseline 10-year survival rate predicted by the Charlson Comorbidity Index (42% vs 69%, p < 0.001) compared to unvaccinated patients. Common symptoms between both groups included shortness of breath (50%), malaise (23%-37%), cough (28%-32%), and fever or chills (25%). Upon matching, adjusted analysis showed significantly higher rates of remdesivir administration to unvaccinated patients (41.3% vs 13.3%, odds ratio (OR): 4.63, 90% confidence interval (CI): 1.98-11.31). Despite higher intensive care unit admission rates among unvaccinated patients (39.1% vs 23.9%, OR: 1.83, 90% CI: 0.74-4.64), this difference did not reach statistical significance. Accordingly, immunization status strongly correlates with patient demographics and differences in inpatient treatment. Larger studies are needed to further assess the vaccine's impact on inpatient outcomes outside of our community.

Piloting the 'Youth Early-intervention Study' ('YES'): Preliminary functional outcomes of a randomized controlled trial targeting social participation and physical well-being in young people with emerging mental disorders.

INTRODUCTION: Young people with mental disorders present with diverse social, vocational, physical, and developmental needs. However, multifaceted interventions are rare. We examine the effectiveness of a clinical trial targeting social participation and physical well-being in young people accessing clinical services. METHODS: The 'Youth Early-intervention Study' ('YES') was an unblinded, two-phase, pilot randomized controlled trial offered as an adjunct to standard clinical care, consisting of group activities. Mixed effects models were used to examine functional outcomes over time measured by the 'Social and Occupational Functioning Assessment Scale', 'Functioning Assessment Short Test', and 'Brief Disability Questionnaire' (items 7 and 8). RESULTS: 133 participants aged 14-25 were recruited. 87 participants completed both arms and 83 participants completed a 12-month post-trial assessment. Functioning improved across all outcomes. While diagnoses differed in functioning at baseline (lower functioning in psychotic and bipolar disorders compared to depression), they did not differ in the rate of improvement across any measure. Randomization groups did not differ in baseline functioning or the rate of improvement, suggesting a non-specific impact of the intervention. Engagement with education increased from 11% at baseline to 51% at 12-months post-trial and full-time employment increased from 8% at baseline to 20% at 12-months post-trial. LIMITATIONS: Small sample, no control group, and unmeasured potential moderators (e.g. neurocognitive impairment). CONCLUSIONS: 'YES' was effective and preliminary positive outcomes were observed across all functional outcomes. Future studies should compare the 'YES' intervention to a treatment-as-usual control condition and conduct a multi-centre trial across early intervention service sites.

No Intern Left Behind: Using a Dedicated Transition to Discipline Block Improves Resident Outcomes.

This article was migrated. The article was marked as recommended. Introduction: A program was developed for incoming PGY-1 residents using the Accreditation Council for Graduate Medical Education milestones ratings. This program detects critical deficiencies and works to correct them as early as possible. Methods: A one month period was used for this transition to discipline block to identify at-risk learners. The block utilized cased-based discussions, interactive lectures, simulations, and clinical core rotations. All activities were tied to milestones measures to recognize deficiencies and provided a goal to correct the individual's progression. Results: Interns that completed the transition to discipline block were compared to the most recent previous class at the same institution. The same number of individuals with critical deficits were found in each class at first milestones rating (4 deficits per class, p value 1.0). The intervention classes had critical deficiencies recognized earlier and all identified deficiencies were extinguished earlier. Medical knowledge as compared by In-Training Examination percentile scores improved (Pre-Intervention Mean Percentile 28.9, Post-Intervention Mean Percentile 49.5, p value 0.005). Discussion: A milestones-based transition to residency block identified critical deficiencies earlier, which allowed for earlier intervention and improvement in resident performance. A similar process may benefit other residency programs.

Piloting a parent and patient decision aid to support clinical trial decision making in childhood cancer.

OBJECTIVE: Families of a child with cancer can find the decision to enrol in a clinical trial challenging and often misunderstand key concepts that underpin trials. We pilot tested "Delta," an online and booklet decision aid for parents with a child with cancer, and adolescents with cancer, deciding whether or not to enrol in a clinical trial. METHODS: We developed Delta in accordance with the International Patient Decision Aid Standards. We conducted a pre-post pilot with parents with a child, and adolescents, who had enrolled in a paediatric phase III clinical trial for newly diagnosed acute lymphoblastic leukaemia. Parents (n = 37) and adolescents (n = 3) completed a questionnaire before and after using Delta (either the website or booklet, based on their preference). RESULTS: Twenty-three parents (62.2%) and three adolescents (100%) reviewed the Delta website. Parents rated Delta as highly acceptable in regard to being clearly presented, informative, easy to read, useful, visually appealing, and easy to use. All participants reported that they would recommend Delta to others and that it would have been useful when making their decision. Parents' subjective (Mdiff= 10.8, SDdiff  = 15.69, P < .001) and objective (OR = 2.25, 95% CI, 1.66-3.04; P < .001) clinical trial knowledge increased significantly after reviewing Delta. CONCLUSIONS: To our knowledge, Delta is the first reported decision aid, available online and as a booklet, for parents and adolescents deciding whether or not to enrol in a paediatric oncology clinical trial. Our study suggests that Delta is acceptable, feasible, and potentially useful.

The Wrong Turn to Tijuana: Dry Beriberi after Gastric Bypass Surgery with Incidental Spinal Stenosis.

Thiamine deficiency is a condition characterized by several different presentations, but one of the most devastating is dry beriberi. It is associated with polyneuropathy and muscle weakness which typically affects the lower extremities and progressively involves the upper extremities. This case outlines a case of a 41-year-old man that presented to the hospital with diffuse weakness and decreased sensation in his legs and hands over a 3-day period. The patient's medical history revealed a gastric bypass surgery 4 months previously in Tijuana, Mexico, with no follow-up, binge drinking on weekends, and emesis in the past few weeks. A physical examination revealed a significant decrease in strength in the lower extremities bilaterally as well as in the hands bilaterally. MRI showed central disc protrusion at T6-T7 that indented the spinal cord, consistent with spinal stenosis. Neurosurgery was counseled and corpectomy was recommended. While awaiting surgery, a low thiamine level resulted. Neurology was consulted, and it was recommended that high-dose IV thiamine treatment be started. An EMG study further supported the diagnosis of thiamine deficiency. The patient received high-dose IV thiamine for 2 weeks and was discharged to acute rehabilitation on a high oral dose of thiamine. While at the rehabilitation facility, the patient continued to achieve functional gains and was later discharged to a skilled nursing facility, where he continues to make progress in his activities of daily living. This case serves to remind practitioners that early recognition and treatment of thiamine deficiency is imperative, especially when other clinical evidence may point to a different diagnosis.

Salivary cortisol reveals overt and hidden anxiety in survivors of childhood cancer attending clinic.

BACKGROUND: Symptoms of anxiety may arise from fear of cancer recurrence and memories of traumatic experiences during treatment. This study aimed to identify changes in mental health and cortisol, a biological marker of stress, associated with oncology surveillance clinic attendance. METHODS: Adolescent and young adult (AYA) survivors of childhood cancer (aged 12-30 years, N = 46) attending a survivorship clinic were recruited. The State-Trait Anxiety Inventory, an anxiety self-rating and open answer question, and salivary cortisol collections were completed two weeks before and one day before clinic, on clinic day and two weeks after. RESULTS: Trait anxiety scores were consistent with the normal population. State anxiety scores two weeks after clinic were significantly lower than baseline (p = 0.02). Cortisol diurnal slopes were flatter than baseline after clinic (p = 0.02). Evening cortisol levels were significantly higher than baseline two weeks post clinic (p = 0.02). LIMITATIONS: Combined results from biological and psychometric assessments can be difficult to interpret. Larger cohorts will further delineate cortisol pathway activity and distress in AYA cancer survivors. CONCLUSIONS: Psychometric evidence indicates that AYA survivors of childhood cancer perceive themselves to be less anxious after a survivorship clinic visit. Biological evidence, however, indicates a dysregulation of the hypothalamic-pituitary-adrenal axis which may be linked to clinic attendance. Weak correlations suggest that cortisol may not be a reliable indicator of self-perceived anxiety. This may be due to confounding lifestyle factors influencing the stress response or potential 'coping strategies' developed during past treatment experience which may, hypothetically, have masked self-perceived anxiety.

Opinions of Young Adults on Re-Consenting for Biobanking.

OBJECTIVE: To evaluate young adult cancer survivor opinions on whether their biobanked tissue and associated de-identified clinical data obtained during their childhood should require re-consent at the age of majority, when parental consent was originally provided. STUDY DESIGN: Thirty young adults (18-34 years old), who were former pediatric oncology patients of The Children's Hospital at Westmead with stored research biospecimens, were recruited. They completed a semistructured interview, which included questions on biobanking re-consent, awareness of biobanked tissue, satisfaction about banked tissue, and independence within the family. Analyses included descriptive and inferential statistics. RESULTS: Sixty percent of participants thought that permission for biobanking should be sought again at adulthood, and the remaining 40% did not think that re-consent was necessary. Seventy percent of participants were unaware of their previously banked tissue, which was dependent upon age at diagnosis. When asked whether they granted permission for their tissue to remain in the biobank, all participants agreed. CONCLUSIONS: Although results on whether young adults prefer to re-consent or not for previously biobanked tissue and corresponding clinical data are equivocal, survivors appear to be highly favorable about ongoing biobanking of their childhood specimens for future unspecified research.

Two Sides of the Same Coin: Cannabis Dependence and Mental Health Problems in Help-Seeking Adolescent and Young Adult Outpatients.

The aim of the current study was to delineate the psychiatric profile of cannabis dependent young people (14-29 years old) with mental health problems (N = 36) seeking treatment via a research study. To do so, the Structured Clinical Interview for DSM-IV-TR Axis I Disorders and the Structured Clinical Interview for DSM-IV Childhood Diagnoses were used to obtain DSM-IV diagnoses, while a modified Timeline Followback interview and self-reports were used to measure cannabis use, cannabis-related problems, and impairment. Most individuals had at least two Axis I disorders in addition to cannabis dependence. Anxiety disorders were common, with posttraumatic stress disorder, social phobia, and generalised anxiety disorder accounting for the majority of these diagnoses. On average, young people reported a moderate degree of dependence and functional impairment, and a substantial number of cannabis-related problems. Although both males and females reported using similar quantities of cannabis per month, females reported using cannabis more frequently than males. The current data suggest that young people who present for cannabis use treatment in the context of a mental health issue may have a variety of psychiatric problems that need addressed and that males and females may have slightly different profiles. If cannabis use treatments are to advance for this population, more attention needs to be paid to the complex issues that young people present to treatment with.

Neurophysiological biomarkers support bipolar-spectrum disorders within psychosis cluster.

BACKGROUND: Mismatch negativity (MMN) and P3a are event-related potentials that index deviance detection and the orienting response, respectively. We have previously shown that the MMN/P3a complex is impaired in patients with schizophrenia and affective spectrum psychoses, which suggests that it may index a common pathophysiology and argues against the purported specificity in schizophrenia. Further research is warranted to determine whether patients with bipolar-spectrum disorders show similar impairments in these biomarkers. METHODS: We assessed patients aged 15-30 years with early schizophrenia-spectrum disorders (schizophrenia, schizoaffective disorder, schizophreniform disorder), early bipolar-spectrum disorders (bipolar I or II, with and without psychotic features) and healthy, matched controls. We acquired MMN/P3a amplitudes during a 2-tone, auditory paradigm with 8% duration deviants. Clinical, psychosocial and neuro psychological assessments were also undertaken. RESULTS: We included 20 patients with schizophrenia-spectrum disorders, 20 with bipolar-spectrum disorders and 20 controls in our study. Both patient groups showed significantly reduced frontocentral MMN and central P3a amplitudes. The schizophrenia-spectrum group had additional impairments in left temporal MMN and frontal P3a. Both patient groups performed worse than controls across psychosocial and clinical measures; however, only the schizophrenia-spectrum group performed significantly worse than controls for cognitive measures. Correlational analyses between patient groups revealed associations between frontocentral or left temporal MMN and psychiatric symptomatology or quality of life measures. LIMITATIONS: Limitations to our study include the modest sample size and the lack of control with regards to the effects of other (i.e., nonantipsychotic) psychotropic medications. CONCLUSION: Compared with patients in early stages of schizophrenia-spectrum disorders, those in the early stages of bipolar-spectrum disorders are similarly impaired in established biomarkers for schizophrenia. These findings support a shared diathesis model for psychotic and bipolar disorders. Furthermore, MMN/P3a may be a biomarker for a broader pathophysiology that overlaps traditional diagnostic clusters.

Delayed preattentional functioning in early psychosis patients with cannabis use.

RATIONALE: Cannabis use is prevalent among the early psychosis (EP) population. The event-related potentials, mismatch negativity (MMN) and P3a are reduced in EP. Cannabinoids have been shown to modulate N-methyl-D-aspartate receptors which are involved in MMN generation. OBJECTIVES: This study is the first to investigate the effects of cannabis use on MMN/P3a in EP. METHODS: EP was defined as a history of psychosis or psychotic symptoms with no progression to date to chronic schizophrenia. Twenty-two EP patients with cannabis use (EP + CANN), 22 non-cannabis-using EP patients (EP-CANN) and 21 healthy controls participated in this study. MMN/P3a was elicited using a two-tone, auditory paradigm with 8% duration deviants. RESULTS: As expected, EP-CANN showed marked reductions in MMN/P3a amplitudes compared to controls. However, EP + CANN showed evidence of a different pattern of neurophysiological expression of MMN/P3a compared to non-using patients, most notably in terms of delayed frontal MMN/P3a latencies. CONCLUSIONS: This study provides further evidence that MMN/P3a deficits are present during early psychosis and suggests that this biomarker may have utility in differentiating substance- from non-substance-related psychoses.

MMN/P3a deficits in first episode psychosis: comparing schizophrenia-spectrum and affective-spectrum subgroups.

BACKGROUND: Reduced mismatch negativity (MMN) and P3a amplitudes are neurophysiological biomarkers for schizophrenia that index deviance detection and the orienting response, respectively. First-episode psychosis (FEP) patients show reduced amplitudes of the 'MMN/P3a complex', but it is unclear whether this occurs across the FEP spectrum. METHODS: Fifty-three young people (17-36 years) were assessed: 17 FEP affective-spectrum (bipolar disorder with psychotic features and major depressive disorder with psychotic features), 18 FEP schizophrenia-spectrum (schizophrenia, schizoaffective disorder, and schizophreniform disorder), and 18 healthy controls. MMN/P3a was acquired during a two-tone, auditory paradigm with 8% duration deviants. Clinical, psychosocial and neuropsychological assessments were also undertaken. RESULTS: FEP schizophrenia- and FEP affective-spectrum showed significantly reduced fronto-central MMN and central P3a amplitudes compared to controls. FEP subgroups also showed significantly poorer cognitive and psychosocial functioning. The combined FEP sample showed significant correlations between fronto-central MMN amplitudes and cognitive measures. DISCUSSION: FEP schizophrenia-spectrum and FEP affective-spectrum were similarly impaired in two biomarkers for schizophrenia. FEP subgroups showed impairments in fronto-central MMN consistent with chronic patients. Similarly, both subgroups showed reductions in P3a; although the affective subgroup showed an 'intermediate' frontal response. These findings suggest that FEP patients with both affective and schizophrenia spectrum diagnoses share common neurobiological disturbances in deviance detection/orienting processes in the early phase of illness.

Chronic cannabis users show altered neurophysiological functioning on Stroop task conflict resolution.

RATIONALE: Chronic cannabis use has been related to deficits in cognition (particularly memory) and the normal functioning of brain structures sensitive to cannabinoids. There is increasing evidence that conflict monitoring and resolution processes (i.e. the ability to detect and respond to change) may be affected. OBJECTIVES: This study examined the ability to inhibit an automatic reading response in order to activate a more difficult naming response (i.e. conflict resolution) in a variant of the discrete trial Stroop colour-naming task. METHODS: Event-related brain potentials to neutral, congruent and incongruent trials were compared between 21 cannabis users (mean 16.4 years of near daily use) in the unintoxicated state and 19 non-using controls. RESULTS: Cannabis users showed increased errors on colour-incongruent trials (e.g. "RED" printed in blue ink) but no performance differences from controls on colour congruent (e.g. "RED" printed in red ink) or neutral trials (e.g. "*****" printed in green ink). Poorer incongruent trial performance was predicted by an earlier age of onset of regular cannabis use. Users showed altered expression of a late sustained potential related to conflict resolution, evident by opposite patterns of activity between trial types at midline and central sites, and altered relationships between neurophysiological and behavioural outcome measures not evident in the control group. CONCLUSIONS: These findings indicate that chronic use of cannabis may impair the brain's ability to respond optimally in the presence of events that require conflict resolution and hold implications for the ability to refrain from substance misuse and/or maintain substance abstention behaviours.

Chronic use of cannabis and poor neural efficiency in verbal memory ability.

INTRODUCTION: The endogenous cannabinoid system is sensitive to the introduction of exogenous cannabinoids such as delta-9-tetrahydrocannabinol, which are known to impact upon memory functioning. We sought to examine the impact of chronic cannabis use upon memory-related brain function via examination of the subsequent memory effect (SME) of the event-related potential (ERP). METHODS: The SME is predictive of recall outcome and originates in structures that are dense with cannabinoid receptors (hippocampus and parahippocampus). The SME and performance on a verbal memory task were compared between 24 cannabis users (mean 17 years of near daily use) in the unintoxicated state and 24 non-using controls. The task involved the presentation of word lists, each with a short delay before recall. ERPs were recorded during encoding and later averaged by outcome (correctly recalled/not recalled). RESULTS: Cannabis users showed poorer recall and altered patterns of SME activation: specifically, attenuation of the negative N4 and an increase in the late positive component. Duration of cannabis use and age of initial use correlated significantly with SME amplitudes. A longer history of use also correlated with greater recall that was related to N4 expression. DISCUSSION: The results indicate that relative to non-using controls, chronic users of cannabis have altered memory-related brain activation in the form of dysfunctional SME production and/or poorer neural efficiency, which is associated with deficits in memory recall. Greater alteration was associated with a longer history of cannabis use and an earlier onset of use. Neuroadaptation to the effects of chronic exposure may additionally play a role.

The chronic effects of cannabis on memory in humans: a review.

Memory problems are frequently associated with cannabis use, in both the short- and long-term. To date, reviews on the long-term cognitive sequelae of cannabis use have examined a broad range of cognitive functions, with none specifically focused on memory. Consequently, this review sought to examine the literature specific to memory function in cannabis users in the nontoxicated state with the aim of identifying the existence and nature of memory impairment in cannabis users and appraising potentially related mediators or moderators. Literature searches were conducted to extract well-controlled studies that investigated memory function in cannabis users outside of the acute intoxication period, with a focus on reviewing studies published within the past 10 years. Most recent studies have examined working memory and verbal episodic memory and cumulatively, the evidence suggests impaired encoding, storage, manipulation and retrieval mechanisms in long-term or heavy cannabis users. These impairments are not dissimilar to those associated with acute intoxication and have been related to the duration, frequency, dose and age of onset of cannabis use. We consider the impact of not only specific parameters of cannabis use in the manifestation of memory dysfunction, but also such factors as age, neurodevelopmental stage, IQ, gender, various vulnerabilities and other substance-use interactions, in the context of neural efficiency and compensatory mechanisms. The precise nature of memory deficits in cannabis users, their neural substrates and manifestation requires much further exploration through a variety of behavioural, functional brain imaging, prospective and genetic studies.

Modifying the sugar moieties of daunorubicin overcomes P-gp-mediated multidrug resistance.

Anthracyclines are widely used in patients for anticancer activity. However, one of the limitations for their clinical use is P-gp-mediated drug resistance in cancer therapy. We hypothesize that modified anthracyclines will retain their anticancer activity, avert P-gp binding, and thus overcome P-gp-mediated drug resistance. Twenty-five daunorubicin analogues were synthesized with slight structure modifications in sugar moieties. Molecular docking, cytotoxicity, and P-gp inhibition assays in drug-resistant leukemia cells (K562/Dox) were used to identify several candidates that avert binding to multidrug-resistant protein (MsbA) and overcome drug resistance. Molecular docking showed that daunorubicin bound to the cavity between the intracellular domain (ICD) and nucleoside binding domain (NBD) of MsbA, which might be the "entry site" for the transport of its substrate. The molecular docking accurately predicted the substrates of multidrug-resistant protein. Several aspects are important for daunorubicin analogue binding to MsbA: (1) the substitution pattern and stereochemistry of the tetracyclic ring and sugar moiety; (2) the hydrogen bond donor or acceptor capability of the substituent at C'-3 and C'-4. Molecular docking, cytotoxicity, and P-gp inhibition assays identified ADNR, ADNR-1, and ADNR-3 for averting P-gp binding and overcoming drug resistance. The replacement of C'-3-NH2 with azido group in daunorubicin not only abolishes the hydrogen bond between the sugar moiety and MsbA but also completely changes the overall binding conformation, and thus averts the binding to MsbA. Cytotoxicity assays confirmed that these compounds showed high sensitivity against drug-resistant cancer cells (K562/Dox) with P-gp overexpression. P-gp inhibition assay indeed confirms that these appropriately modified compounds avert P-gp binding and thus overcome P-gp-mediated drug resistance.

Enzyme specific activation of benzoquinone ansamycin prodrugs using HuCC49DeltaCH2-beta-galactosidase conjugates.

To activate prodrugs for cancer treatment, an anti-TAG-72 antibody (HuCC49DeltaCH2) was used for delivery of an activation enzyme (beta-galactosidase) to specifically activate a geldanamycin prodrug (17-AG-C2-Gal) against colon cancer. The geldanamycin prodrug 17-AG-C2-Gal was synthesized by coupling a galactose-amine derivative with geldanamycin at the C-17 position. Molecular docking with two different programs (Affinity and Autodock) showed that the prodrug (17-AG-C2-Gal) was unable to bind to Hsp90; however, the product (17-AG-C2), enzymatically cleaved by beta-galactosidase conjugate, bound to Hsp90 in a similar way as geldanamycin and 17-AG. The computational docking results were further confirmed in experimental testing by the tetrazolium [3-(4,5-dimethythiazol-2-yl)]-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay and mass spectrometry. HuCC49DeltaCH2 was chemically conjugated to beta-galactosidase. The antibody-enzyme conjugate was able to target tumor antigen TAG-72 with the well-preserved enzymatic activity to activate 17-AG-C2-Gal prodrug. The released active drug 17-AG-C2 was demonstrated to induce up to 70% AKT degradation and enhance anticancer activity by more than 25-fold compared to the prodrug.