Cellular and Organismal Toxicity of the Anti-Cancer Small Molecule, Tolfenamic Acid: a Pre-Clinical Evaluation

Abstract

Background/Aims: The small molecule, Tolfenamic acid (TA) has shown anti-cancer activity in pre-clinical models and is currently in Phase I clinical trials at MD Anderson Cancer Center Orlando. Since specificity and toxicity are major concerns for investigational agents, we tested the effect of TA on specific targets, and assessed the cellular and organismal toxicity representing pre-clinical studies in cancer. Methods: Panc1, L3.6pl, and MiaPaCa-2 (pancreatic cancer), hTERT-HPNE(normal), and differentiated/un-differentiated SH-SY5Y (neuroblastoma) cells were treated with increasing concentrations of TA. Cell viability and effect on specific molecular targets, Sp1 and survivin were determined. Athymic nude mice were treated with vehicle or TA (50mg/kg, 3times/week for 6 weeks) and alterations in the growth pattern, hematocrit, and histopathology of gut, liver, and stomach were monitored. Results: TA treatment decreased cell proliferation and inhibited the expression of Sp1 and survivin in cancer cells while only subtle response was observed in normal (hTERT-HPNE) and differentiated SH-SY5Y cells. Mice studies revealed no effect on body weight and hematocrit. Furthermore, TA regimen did not cause signs of internal-bleeding or damage to vital tissues in mice. Conclusion: These results demonstrate that TA selectively inhibits malignant cell growth acting on specific targets and its chronic treatment did not cause apparent toxicity in nude mice.

Sp1 transcription factor: A long-standing target in cancer chemotherapy

“…Many of the drugs and natural molecules reviewed here can be considered safe enough (D'Incalci, et al, 2007;Minotti, et al, 2004;Núñez, et al, 2012;Sankpal, et al, 2013), which would support or accelerate their clinical usage. However, experimental data should be handled with care in translational medicine based on inhibiting Sp transcription factors, given that Sp1 and/or Sp3 can cooperatively activate several genes through the interaction with other transcription factors or their DNA-binding sites Vizcaíno, et al, 2012;Wierstra, 2008).…”

“…2) is an anti-inflammatory agent in phase I clinical trials (Sankpal, et al, 2013). In pancreatic cancer cells, tolfenamic acid inhibits VEGF expression, an effect that has been associated with the down-regulation of Sp-dependent trans-activation of the VEGF promoter (Abdelrahim, et al, 2006).…”

Fluorouracil induces autophagy-related gastric carcinoma cell death through Beclin-1 upregulation by miR-30 suppression

“…Gastric carcinoma (GC) is one of the most frequently diagnosed cancers worldwide, whereas it ranks the second among all cancer-related deaths [1][2][3][4][5][6][7]. Regionally, the highest incidence of GC rests in Eastern Asia [1][2][3][4][5][6][7].…”

“…Regionally, the highest incidence of GC rests in Eastern Asia [1][2][3][4][5][6][7]. Currently, surgical treatment is the main therapy of GC, although the outcome of the treatment is far from satisfaction [8][9][10][11].…”

Tolfenamic acid-induced alterations in genes and pathways in pancreatic cancer cells

“…The anti-cancer activity of TA is associated with the degradation of the specificity protein 1 (Sp1) transcription factor and the inhibition of expression of its downstream targets such as cMet, VEGF, and Survivin [15, 16, 18]. Unlike many other anti-cancer NSAIDs, TA works via a COX-independent mechanism and, accordingly, has a significantly reduced toxicity profile [20]. Decrease in Sp1 protein expression by TA treatment has been demonstrated in several cancer models, both in vitro and in vivo [14–16].…”