RT-112-luc Orthotopic Mouse Model Service for Bladder Cancer

The RT-112-luc orthotopic mouse model captures the luminal-differentiated biology of human non-muscle invasive bladder cancer within an immunodeficient host, combining stable firefly luciferase expression with preserved FGFR3-driven signaling and intact epithelial architecture for quantitative, longitudinal preclinical assessment. Alfa Cytology deploys this human xenograft platform with authenticated cell-line provenance, calibrated IVIS imaging protocols, and histopathological correlation, delivering photon-flux datasets that map directly onto tumor volume and differentiation status throughout the therapeutic window.

Overview of RT-112-luc Orthotopic Mouse Model for Bladder Cancer

RT-112-luc is a genetically tagged derivative of the RT-112 human bladder transitional cell carcinoma line, originally established in 1973 from a grade II (G2) tumor excised from a female patient with untreated primary urinary bladder carcinoma. The parental line is molecularly classified as a luminal-subtype urothelial carcinoma, distinguished by FGFR3 gene amplification and high-level protein expression—a driver alteration prevalent in low- to intermediate-grade papillary bladder tumors. Unlike aggressive basal-like lines, RT-112 retains wild-type TP53 and functional RB1, exhibits strong E-cadherin and cytokeratin 20 positivity, and maintains uroplakin II expression indicative of preserved urothelial differentiation. Stable lentiviral transduction with firefly luciferase introduces a quantifiable optical reporter without altering growth kinetics or drug sensitivity, enabling non-invasive tumor burden monitoring that scales linearly with cell number. When implanted orthotopically into the bladder wall of athymic nude mice, RT-112-luc cells achieve a 90% tumor take rate and generate moderately growing, well-differentiated masses that recapitulate the indolent yet persistent nature of human NMIBC.

Fig 1. Tumor growth kinetics of murine orthotopic a RT112luc and b RT112r GEMCI²⁰luc xenografts. (Vallo, Stefan, et al., 2016)

The model's luminal molecular architecture—further supported by high GATA3 and FOXA1 expression—renders it particularly suited for evaluating FGFR3-targeted tyrosine kinase inhibitors, differentiation-restoring agents, and intravesical therapies aimed at preventing progression from superficial carcinoma to muscle-invasive disease. Bioluminescence imaging following D-luciferin administration generates photon-flux values that correlate to tumor volume (approximately 10×10⁸ photons/s per 10 mm³), allowing precise kinetic profiling of treatment response. The absence of epithelial-to-mesenchymal transition markers and the retention of intact apoptotic signaling further distinguish RT-112-luc as a representative model for luminal-predominant bladder cancer biology.

Cell Line Information: RT-112-luc

RT-112-luc preserves the luminal differentiation status, FGFR3-driven oncogenic signaling, and moderate growth kinetics of its parental human urothelial carcinoma line while adding a quantifiable optical reporter. The table below details its origin, molecular profile, and imaging-compatible properties.

Our Services

Alfa Cytology constructs and manages RT-112-luc orthotopic cohorts with an emphasis on luminal-subtype fidelity, leveraging authenticated FGFR3-amplified cell stocks, calibrated luciferase-signal validation, and direct intramural surgical implantation to achieve consistent tumor take rates. Our analytical pipeline integrates bioluminescence quantification with small-animal ultrasound and terminal immunohistochemistry for E-cadherin, CK20, and Ki-67, ensuring that every dataset reflects the differentiated, moderately growing phenotype characteristic of human NMIBC.

Workflow of RT-112-luc Orthotopic Mouse Model Construction

Construction of the RT-112-luc orthotopic model centers on direct intramural bladder-wall injection, a technique that bypasses urothelial barrier constraints and ensures reliable tumor engraftment in this moderately tumorigenic, differentiation-retained human line. The workflow below details each phase from reporter validation through longitudinal imaging to terminal histopathological confirmation.

1. Luciferase Expression Validation and Cell Preparation: RT-112-luc cells are expanded under blasticidin selection pressure to maintain reporter stability. An in vitro Bright-Glo or equivalent luciferase assay is performed 48 hours prior to implantation to confirm homogeneous, high-level bioluminescence and linear signal-to-cell-number correlation (R² > 0.95). Viability is assessed by trypan blue exclusion, with only suspensions exceeding 90% viability accepted. Cells are washed twice in PBS, counted, and resuspended at 1×10⁷ cells/mL in serum-free medium or PBS on ice.
2. Animal Preparation and Anesthesia: Female athymic nude mice (nu/nu), 6–8 weeks old, are acclimatized for a minimum of one week under SPF barrier conditions. On the procedure day, general anesthesia is induced via isoflurane inhalation (3% for induction, 1.8% maintenance at 2 L/min oxygen) or intraperitoneal sodium pentobarbital (60 mg/kg). Depth of anesthesia is confirmed by absence of the toe-pinch reflex. Buprenorphine and meloxicam are administered subcutaneously for perioperative analgesia. Mice are placed on a heated surgical pad in supine position, and the lower abdominal wall is disinfected with chlorhexidine.
3. Surgical Exposure of the Bladder: A low transverse laparotomy is performed to exteriorize the urinary bladder. The bladder is gently emptied by manual compression and stabilized with moistened gauze. A 25-gauge needle is used to create a small puncture in the ventral bladder wall, or a 30-gauge Hamilton syringe is inserted directly into the detrusor muscle layer for intramural delivery.
4. Intramural Cell Injection: The prepared RT-112-luc cell suspension (50 µL containing 5×10⁵ cells) is injected slowly into the bladder wall at a controlled rate to minimize back-leakage. The needle is held in place for 30 seconds after injection to allow matrix deposition and prevent reflux. The bladder is then returned to the abdominal cavity, and the laparotomy incision is closed in two layers with absorbable suture.
5. Postoperative Recovery and Health Surveillance: Mice are transferred to a warmed recovery chamber and monitored until fully mobile. Body weight, hydration status, and general behavior are recorded daily for the first 72 hours. Analgesia is maintained according to institutional IACUC guidelines. Mice exhibiting >15% body-weight loss, signs of urinary obstruction, or wound dehiscence are flagged for veterinary assessment.
6. Longitudinal Bioluminescence Imaging Protocol: Tumor establishment and growth are monitored via serial IVIS imaging performed every 4 days beginning on day 5 post-inoculation. Mice receive intraperitoneal D-luciferin (150–200 µg/kg body weight) and are imaged under continuous isoflurane anesthesia at 10 and 14 minutes post-injection; the average photon flux is used for statistical analysis. Acquisition parameters (exposure time, binning, f/stop) are locked across all sessions. Regions of interest are drawn over the bladder, and total photon flux (photons/second) is quantified and normalized to baseline values. Tumor volume is estimated using the validated correlation of 10×10⁸ photons/s ≈ 10 mm³.
7. Terminal Necropsy and Histopathological Correlation: At humane endpoint or protocol-defined timepoints (typically 3–4 weeks), a final bioluminescence image is acquired. Mice are euthanized, and the bladder is excised, weighed, and opened longitudinally for macroscopic inspection. Tumor differentiation status is confirmed by hematoxylin and eosin (H&E) staining and immunohistochemistry for E-cadherin, cytokeratin 20, uroplakin II, Ki-67, and CD31. Tissues are partitioned for snap-frozen molecular extraction (RNA/DNA/protein) and flow-cytometric analysis as dictated by study objectives.

Fig 2. RT-112-luc Orthotopic Mouse Model construction workflow.

Case Study-RT-112-luc Orthotopic Mouse Model Development

In a preclinical program designed to evaluate a novel FGFR3-selective tyrosine kinase inhibitor, Alfa Cytology established an orthotopic RT-112-luc cohort to leverage the line's endogenous receptor amplification and luminal differentiation status. Following validated intramural injection, bioluminescence imaging confirmed 90% tumor engraftment with detectable photon flux by day 5 and moderate exponential growth through day 25. The study architecture included a vehicle control arm, a low-dose FGFR3 inhibitor arm, and a combination arm pairing the inhibitor with intravesical mitomycin C. Serial imaging revealed divergence in photon-flux trajectories between monotherapy and combination arms by day 16, while terminal immunohistochemistry demonstrated treatment-dependent preservation of E-cadherin architecture and reduced Ki-67 proliferation indices in the combination group. These imaging-anchored, differentiation-aware datasets provided the sponsor with pharmacodynamic evidence supporting further formulation development and biomarker strategy refinement.

Why Choose Alfa Cytology?

Partnering with Alfa Cytology for your RT-112-luc orthotopic study ensures access to a preclinical platform where luminal-subtype authenticity, optical traceability, and endpoint analytical depth are aligned to support FGFR3-targeted and differentiation-focused therapeutic development.

• Authenticated RT-112-luc cells with documented FGFR3 amplification, wild-type TP53, and preserved luminal-marker expression guarantee biologically faithful modeling of low- to intermediate-grade human bladder cancer.
• Direct intramural surgical implantation achieves a 90% tumor take rate in athymic nude mice, circumventing the engraftment variability observed with intravesical instillation in this moderately tumorigenic, differentiation-retained line.
• Calibrated IVIS imaging with locked acquisition parameters and validated photon-flux-to-volume correlation (10×10⁸ photons/s ≈ 10 mm³) delivers statistically robust longitudinal quantification of tumor burden and treatment response.
• The model's intact apoptotic signaling and wild-type p53 background support mechanistic studies of DNA-damage response, differentiation restoration, and chemotherapy-induced senescence in a luminal-predominant context.
• Complementary availability of cisplatin-resistant (RT112rCDDP) and gemcitabine-resistant (RT112rGEMCI20) sublines—both with luciferase-tagged variants—enables parallel evaluation of acquired resistance mechanisms and second-line strategies.
• All studies are conducted within SPF barrier facilities under IACUC-approved protocols, with full chain-of-custody documentation, E-cadherin/CK20/Ki-67 immunohistochemistry packages, and GLP-compatible data deliverables available.

Contact Us

If your bladder cancer discovery pipeline requires a luminal-subtype, FGFR3-driven orthotopic model with real-time bioluminescence quantification and proven differentiation fidelity, reach out to Alfa Cytology to discuss how our RT-112-luc platform can advance your preclinical objectives. Our scientific team will design a customized imaging study, select optimal endpoint analytics for your therapeutic mechanism, and provide a comprehensive project proposal. Contact us today to translate luminal bladder cancer biology into actionable, data-driven insights.

For research use only. Not intended for any clinical use.