https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4859676/

Quercetin had been widely used during the Corona-year[s]

It would be very interesting to know is the frequency of bladder cancer has decrease during this period or if the severity has been less. Probably far too short period to judge this.

Discussion

Bladder cancer remains one of the main malignancies that affect the genitourinary tract [2931]. In fact, the main problem of this disease is that even if it is superficial at diagnostic moment, the current treatment, which is transurethral resection followed by BCG intravesical administration, is not fully effective in preventing tumor recurrence and progression. Therefore, fairly amount of research groups has studied several natural products, produced by secondary metabolism of plants, in an attempt to find new and better treatments to bladder tumors. Quercetin, which exists in nearly all plants, has a long history as a normal part of the human diet [32]. An increasing number of studies have revealed the biological and pharmacological activities of quercetin, which are beneficial to human health including its selective antiproliferative effects and cell death, predominantly through an apoptotic mechanism in cancer cell lines but not in normal cells [33]. Recent data from literature indicate the potential role of quercetin for pharmacologic treatment, including its activity against bladder cancer [28,34]. However, the underlying molecular mechanisms remain poorly understood. In the present study, we found that quercetin inhibited cell proliferation and induced cell death via activating AMPK signaling pathway.

In this work, proliferation data obtained from MTT assays revealed that quercetin treatment significantly suppressed three bladder cancer cells proliferation. Furthermore, colony information and migration data obtained from clonogenic assay and scratch wound assay confirmed the suppression effect of quercetin on bladder cancer cell proliferation or motility. The mechanism of quercetin in bladder cancer cells was analysized by Western blots and the results showed that the expression of p-AMPK was increased while p-p70s6k was strongly decreased after treated with quercetin. These data collectively demonstrate that quercetin exerts anticancer effect on bladder cancer via AMPK signaling pathway. We also found out that quercetin led to a dose-dependent cell apoptosis through FITC apoptosis assay. Wound healing assay also reveals that quercetin suppresses migration of bladder cancer cells.

In conclusion, the results of this study show the anti-proliferative potential of quercetin on tumor cells by activating AMPK signaling pathway and provides solid foundation on the clinical application of quercetin in bladder cancer treatment.