# Norfloxacin Derivative with Carbazole at C-7 FQB-1 Induces Cytotoxic, Antiproliferative, and Antitumor Effects in an Experimental Lung Carcinoma Model

## TL;DR

A new norfloxacin derivative, FQB-1, shows strong anti-cancer effects in a lung cancer model by reducing tumor growth and viability.

## Contribution

FQB-1, a novel fluoroquinolone derivative, demonstrates potent anti-tumor activity in both in vitro and in vivo lung cancer models.

## Key findings

- FQB-1 showed strong binding to human topoisomerase with a binding affinity of –9.8 kcal/mol.
- In vitro tests showed significant cytotoxic and anti-proliferative effects at 50–150 µg/mL.
- In vivo treatment reduced tumor volume and increased necrotic regions in mice.

## Abstract

Background: Cancer remains a leading cause of morbidity and mortality worldwide. According to the World Health Organization (WHO), lung cancer is the most prevalent type of cancer among both men and women. Despite the various pharmacological and biological treatments available for lung cancer, their effectiveness has often fallen short, and the side effects can be severe. Therefore, there is an ongoing need to identify and develop novel compounds with enhanced anti-tumor efficacy and improved safety profiles. Research has shown that fluoroquinolone derivatives exhibit a broad cytotoxic spectrum comparable to other drugs used in clinical chemotherapy. Objective: The aim of this work was to synthesize and evaluate the cytotoxic, anti-proliferative, and anti-tumor effects of FQB-1, a novel fluoroquinolone derivative. Results: In silico molecular docking analysis demonstrated a strong interaction between FQB-1 and human topoisomerase, with a binding affinity score of –9.8 kcal/mol. In vitro cytotoxicity and anti-proliferative assays were conducted using the Lewis Lung Carcinoma (LLC) cell line. FQB-1 was tested at concentrations of 2.5, 5.0, 25.0, 50.0, 100.0, and 150.0 µg/mL. Significant cytotoxic and anti-proliferative effects were observed at concentrations of 50–150 µg/mL after 24 h of treatment. To evaluate FQB-1′s efficacy in vivo, a syngeneic tumor model was established in C57BL/6 mice. Treatment with FQB-1 (100 mg/kg) resulted in a marked reduction in tumor volume compared to the untreated control group. Histopathological analysis of tumor tissues from treated animals revealed a decrease in mitotic index and an increase in necrotic regions, indicating compromised tumor viability. Conclusions: FQB-1 exhibits cytotoxic and anti-proliferative effects and can reduce tumor growth while compromising tumor viability.