Targeting kinome reprogramming in ESR1 fusion-driven metastatic breast cancer

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Background: Genomic analysis has recently identified multiple ESR1 gene translocations in estrogen receptor-alpha positive (ERα+) metastatic breast cancer (MBC) that encode chimeric proteins whereby the ESR1 ligand binding domain is replaced by C-terminal sequences from many different gene partners. Transcriptionally active ESR1 fusions promoted hormone-independent cell growth, motility and resistance to endocrine therapy. The diversity of partner genes creates a considerable diagnostic challenge and no targeted treatments exist for ESR1 translocated tumors. Thus, we have established a transcriptional signature to diagnose the presence of an active ESR1 fusion (PMID: 34711608) and developed novel targeted therapies against ESR1 fusion-driven biology. Methods: Fifteen ESR1 fusion cDNA constructs were expressed in ER+ breast cancer cell lines by lentiviral transduction. Cell growth was assayed by Alamar blue assay. A mass spectrometry (MS)-based Kinase Inhibitor Pulldown Assay (KIPA) and tandem mass tag-based proteomics were performed to identify ESR1 fusion-driven druggable kinases for subsequent pharmacological inhibition. Results: KIPA profiling demonstrated an increase of multiple receptor tyrosine kinases including RET in T47D cells expressing active ESR1 fusions. Inhibition of RET by repurposing an FDA-approved drug significantly suppressed ESR1 fusion-driven cell growth in vitro, suggesting that despite marked diversity in the 3’ partners, common kinase activities were elevated and targetable. Proteogenomic profiling, including whole exome sequencing, RNA sequencing, and MS-based proteomics and phosphoproteomics were further performed on 22 ER+ patient-derived xenograft (PDX) tumors, which demonstrated different degrees of estradiol dependence. These integrated “omic” profiles defined targetable genes/pathways and predict tumor subsets that could be responsive to kinase inhibition therapy from this biologically heterogeneous panel of PDX tumors. WHIM18, a PDX naturally harboring the ESR1-YAP1 fusion showed elevated level of RET and CDK4/6 pathways. The tumor volumes were significantly reduced by the RET inhibitor. CDK4/6 inhibitor treatment showed similar tumor reductions to RET inhibition. Interestingly, WHIM9 PDX that expressed wild-type ESR1 conferred a comparable kinome profile to WHIM18. The tumor growth was significantly suppressed by RET or CDK4/6 inhibition. Therefore, pharmacological experiments validated proteogenomics-predicted drug response in two tested ER+ PDX models. Conclusions: Proteogenomics characterization of PDX tumors can drive clinical trial hypotheses. Here, we reveal therapeutic kinase vulnerabilities in ESR1 fusion-driven tumors as exemplified by RET inhibition, which will lay the framework for future clinical trials.

The effect of urethral introducer tip catheters on the incidence of urinary tract infection outcomes in spinal cord injured patients

PURPOSE

We attempted to determine whether an introducer tip catheter reduces urinary tract infection in spinal cord injured patients on intermittent catheterization.

MATERIALS AND METHODS

The introducer tip catheter bypasses the colonized 1.5 cm. of the distal urethra. Enrolled patients were prospectively entered into the study in alternate groups depending on whether they reflex voided: group 1--on intermittent catheterization with the introducer tip catheter but not voiding spontaneously or wearing an external urinary catheter, group 2--same as group 1 but using a nonintroducer tip catheter; group 3--on intermittent catheterization with the introducer tip catheter, voiding by reflex and wearing an external urinary catheter, and group 4--same as group 3 but using a nonintroducer tip catheter.

RESULTS

Statistical significance was shown when comparing patients using versus not using the introducer tip catheter regardless of whether an external urinary catheter was worn (p = 0.0121). A greater difference was noted between patients using and not using the introducer tip catheter in the intermittent catheterization only group (p = 0.0093).

CONCLUSIONS

The introducer tip catheter decreased urinary tract infections in hospitalized men with spinal cord injury on intermittent catheterization.

Comparison of bladder management complication outcomes in female spinal cord injury patients

A total of 70 female spinal cord injury patients was retrospectively analyzed for outcomes of long-term bladder management. Three groups were defined: 1) 23 patients on intermittent catheterization, 2) 25 treated by reflex voiding and incontinence padding, and 3) 22 with an indwelling catheter. Mean years of using the specific bladder management technique were 8.5 +/- 4.7, 15.8 +/- 7.3 and 16.7 +/- 9.0 for the 3 groups, respectively. All patients were evaluated for long-term complications. There were 4 major complications (17%) in the intermittent catheterization group, 10 (40%) in the padding group and 58 (greater than 200%) in the indwelling catheter group. The aggregate difference in complication rates among the 3 group was highly significant (p < 0.00001). Of comparable long-term patients (11 to 23 years) there were no major complications among 6 on intermittent catheterization, 8 among 14 who use padding and 21 among 9 with an indwelling catheter. The differences among the groups remained significant (p < 0.00001). Additional analyses showed highly significant differences between the catheter group and the other 2 groups (intermittent catheterization p = 0.0009 and padding p = 0.0005), and a difference that approached significance between the intermittent catheterization and padding groups (p = 0.085). The results strongly support intermittent catheterization as the optimal management of female patients following spinal cord injury given that other factors, in particular independent hand function or the need for appropriate assistance, are considered.

Differences in urinary tract infections in male and female spinal cord injury patients on intermittent catheterization

Intermittent catheterization has gained wide acceptance for use in hospitalized patients following spinal cord injury. Most studies evaluating this procedure, however, look only at the infection rate in the male SCI population. In this study the rate and type of infection encountered in the male and female SCI population were evaluated in an inpatient hospital environment. Fifty four patients who were undergoing intermittent catheterization with the MMG/O'Neil catheter system were evaluated. All patients were similar with regard to level of injury and bladder management. There were 45 males and nine females in our study group (n = 45). A total of 10,945 catheterizations were performed with 75 infections indentified. The overall infection rate was 0.68% or one infection for every 146 catheterizations. Of the 45 males there were 58 infections of which 11 (18%) were E. coli. This contrasts with the female population (9) in which there were 17 infections with nine (53%) being E. coli. While a variety of infecting organisms were present in males, females were colonized with either E. coli, enterococcus or Klebsiella. While hospital based intermittent catheterization would appear to be associated with an acceptable low incidence of urinary tract infections (0.68%), infected females have a higher incidence of E. coli (53%) compared to the male population (18%). This study also demonstrated that female patients had a significantly higher infection rate than males (nine females with 17 infections compared to 45 males with 58 infections over the same time period). The higher incidence of urinary tract infections in females with E. coli perhaps is related to the proximity of bowel/stool contamination.

Effect of external urinary collection system on colonization and urinary tract infections with Pseudomonas and Klebsiella in men with spinal cord injury

Urinary tract infection of men with spinal cord injuries has been associated with a high incidence of colonization of the patients with gram-negative bacilli. We have examined the factors influencing colonization of 119 patients with Pseudomonas and Klebsiella and studied methods of reducing this colonization. The urethra, perineum, rectum, and drainage bag of all patients were cultured on selective media at two week intervals until discharge. The use of the external urinary collection system (EUCS) was discontinued in a group of patients at night, in an attempt to reduce colonization. Pseudomonas and Klebsiella were isolated from one or more body sites in 65 percent and 69 percent of total culture days. The urethra, perineum, rectum, and drainage bags were reservoirs of Pseudomonas and Klebsiella in men with spinal cord injuries, even in the absence of urinary tract infections. The EUCS proved to be an important factor influencing colonization. Pseudomonas and Klebsiella colonization was higher in patients using the EUCS. Removal of the EUCS at night reduced urethral colonization with Pseudomonas, but did not significantly reduce urethral colonization with Klebsiella. The prevalence of bacteriuria with Pseudomonas and Klebsiella was not significantly influenced by the use of the EUCS.

Morning report. Role of the clinical librarian

The educational value of morning report should be enhanced by thorough evaluation of the medical literature. We added a clinical medical librarian (CML) program to our morning report 2 1/2 years ago to provide rapid, complete access to reference material relevant to topics discussed in morning report. MEDLINE searches and references are made available on a same-day basis; cumulative lists of these are provided to the staff and house staff at bimonthly and yearly intervals. All house staff used the CML service to some degree and the majority found it to be of value in making patient care decisions. Since the inception of the CML program, the medical library has noted a more than twofold increase in the number of on-line reference searches and a similar increase in requests for searches by house staff. Patient care decisions have been improved through ready access to current medical literature, and the teaching program has been enhanced by the creation of the CML program as an integral part of morning report.