A <i>cis</i>-regulatory antisense RNA represses translation in <i>Vibrio cholerae</i> through extensive complementarity and proximity to the target locus

<div><p>As with all facultative pathogens, <i>Vibrio cholerae</i> must optimize its cellular processes to adapt to different environments with varying carbon sources and to environmental stresses. More specifically, in order to metabolize mannitol, <i>V. cholerae</i> must regulate the synthesis of MtlA, a mannitol transporter protein produced exclusively in the presence of mannitol. We previously showed that a <i>cis</i>-acting small RNA (sRNA) expressed by <i>V. cholerae,</i> MtlS, appears to post-transcriptionally downregulate the expression of <i>mtlA</i> and is produced in the absence of mannitol. We hypothesized that since it is complementary to the 5′ untranslated region (UTR) of <i>mtlA</i> mRNA, MtlS may affect synthesis of MtlA by forming an <i>mtlA</i>-MtlS complex that blocks translation of the mRNA through occlusion of its ribosome binding site. To test this hypothesis, we used in vitro translation assays in order to examine the role MtlS plays in <i>mtlA</i> regulation and found that MtlS is sufficient to suppress translation of transcripts harboring the 5′ UTR of <i>mtlA</i>. However, in a cellular context, the 5′ UTR of <i>mtlA</i> is not sufficient for targeted repression by endogenous MtlS; additional segments from the coding region of <i>mtlA</i> play a role in the ability of the sRNA to regulate translation of <i>mtlA</i> mRNA. Additionally, proximity of transcription sites between the sRNA and mRNA significantly affects the efficacy of MtlS.</p></div

Association Between Sites of Metastasis and Outcomes With Immune Checkpoint Inhibitors in Advanced Urothelial Carcinoma

BackgroundSites of metastasis have prognostic significance in advanced urothelial carcinoma (aUC), but more information is needed regarding outcomes based on metastatic sites in patients treated with immune checkpoint inhibitors (ICI). We hypothesized that presence of liver/bone metastases would be associated with worse outcomes with ICI.MethodsWe identified a retrospective cohort of patients with aUC across 26 institutions, collecting demographics, clinicopathological, treatment, and outcomes information. Outcomes were compared with logistic (observed response rate; ORR) and Cox (progression-free survival; PFS, overall survival; OS) regression between patients with/without metastasis beyond lymph nodes (LN) and those with/without bone/liver/lung metastasis. Analysis was stratified by 1st or 2nd+ line.ResultsWe identified 917 ICI-treated patients: in the 1st line, bone/liver metastases were associated with shorter PFS (Hazard ratio; HR: 1.65 and 2.54), OS (HR: 1.60 and 2.35, respectively) and lower ORR (OR: 0.48 and 0.31). In the 2nd+ line, bone/liver metastases were associated with shorter PFS (HR: 1.71 and 1.62), OS (HR: 1.76 and 1.56) and, for bone-only metastases, lower ORR (OR: 0.29). In the 1st line, LN-confined metastasis was associated with longer PFS (HR: 0.53), OS (HR:0.49) and higher ORR (OR: 2.97). In the 2nd+ line, LN-confined metastasis was associated with longer PFS (HR: 0.47), OS (HR: 0.54), and higher ORR (OR: 2.79); all associations were significant.ConclusionBone and/or liver metastases were associated with worse, while LN-confined metastases were associated with better outcomes in patients with aUC receiving ICI. These findings in a large population treated outside clinical trials corroborate data from trial subset analyses

Association of the Time to Immune Checkpoint Inhibitor (ICI) Initiation and Outcomes With Second Line ICI in Patients With Advanced Urothelial Carcinoma

BackgroundEarly progression on first-line (1L) platinum-based therapy or between therapy lines may be a surrogate of more aggressive disease and poor outcomes in advanced urothelial carcinoma (aUC), but its prognostic role regarding immune checkpoint inhibitor (ICI) response and survival is unclear. We hypothesized that shorter time until start of second-line (2L) ICI would be associated with worse outcomes in aUC.Patients and methodsWe performed a retrospective multi-institution cohort study in patients with aUC treated with 1L platinum-based chemotherapy, who received 2L ICI. Patients receiving switch maintenance ICI were excluded. We defined time to 2L ICI therapy as the time between the start of 1L platinum-based chemotherapy to the start of 2L ICI and categorized patients a priori into 1 of 3 groups: less than 3 months versus 3-6 months versus more than 6 months. We calculated overall response rate (ORR) with 2L ICI, progression-free survival (PFS) and overall survival (OS) from the start of 2L ICI. ORR was compared among the 3 groups using multivariable logistic regression, and PFS, OS using cox regression. Multivariable models were adjusted for known prognostic factors.ResultsWe included 215, 215, and 219 patients in the ORR, PFS, and OS analyses, respectively, after exclusions. ORR difference did not reach statistical significance between patients with less than 3 months versus 3-6 months versus more than 6 months to 2L ICI. However, PFS (HR 1.64; 95% CI 1.02-2.63) and OS (HR 1.77; 95% CI 1.10-2.84) was shorter among those with time to 2L ICI less than 3 months compared to those who initiated 2L ICI more than 6 months.ConclusionAmong patients with aUC treated with 2L ICI, time to 2L ICI less than 3 months was associated with lower, but not significantly different ORR, but shorter PFS and OS compared to 2L ICI more than 6 months. This highlights potential cross resistance mechanisms between ICI and platinum-based chemotherapy