Aryl derivatives of 3H-1,2-benzoxathiepine 2,2-dioxide as carbonic anhydrase inhibitors

A new series of homosulfocoumarins (3H-1,2-benzoxathiepine 2,2-dioxides) possessing various substitution patterns and moieties in the 7, 8 or 9 position of the heterocylic ring were prepared by original procedures and investigated for the inhibition of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms, the human (h) hCA I, II, IX and XII. The 8-substituted homosulfocoumarins were the most effective hCA IX/XII inhibitors followed by the 7-substituted derivatives, whereas the substitution pattern in position 9 led to less effective binders for the transmembrane, tumour-associated isoforms IX/XII. The cytosolic isoforms hCA I and II were not inhibited by these compounds, similar to the sulfocoumarins/coumarins investigated earlier. As hCA IX and XII are validated anti-tumour targets, with one sulphonamide (SLC-0111) in Phase Ib/II clinical trials, finding derivatives with better selectivity for inhibiting the tumour-associated isoforms over the cytosolic ones, as the homosulfocoumarins reported here, is of crucial importance.

Induction of ROS‑mediated cell death and activation of the JNK pathway by a sulfonamide derivative

The emergence of colorectal cancer in developed nations can be attributed to dietary habits, smoking, a sedentary lifestyle and obesity. Several treatment regimens are available for primary and metastatic colorectal cancer; however, these treatment options have had limited impact on cure and disease‑free survival, and novel agents need to be developed for treating colorectal cancer. Thus, the objective of this study was to explore the anticancer mechanism of a benzo(1,3)dioxol‑based derivative of sulfonamide. The compound's inhibitory effect on cell proliferation was determined using the MTT assay and the xCelligence RTDP machine. Alternations in the expression of Bcl‑2 and inhibitor of apoptosis protein families were detected by western blotting. Apoptotic marker protein expression, including cytochrome c and cleaved poly(ADP‑ribose)polymerase was measured in the cytosolic extract of cells. Apoptosis and necrosis were detected by flow cytometry and immunofluorescence. Reactive oxygen species (ROS), and activation of caspase‑3 and caspase‑7 were measured using flow cytometry. Activation of the JNK pathway was detected by western blotting. We investigated the molecular mechanism of action of the sulfonamide derivative on colorectal cancer cells and found that the compound possesses a potent anticancer effect, which is primarily exerted by inducing apoptosis and necrosis. Interestingly, this compound exhibited little antiproliferative effect against the normal colonic epithelial cell line FHC. Furthermore, our results showed that the compound could significantly increase ROS production. Apoptosis induction could be attenuated by the free oxygen radical scavenger N‑acetyl cysteine (NAC), indicating that the antiproliferative effect of this compound on colorectal cancer cells is at least partially dependent on the redox balance. In addition, JNK signaling was activated by treatment with this derivative, which led to the induction of apoptosis. On the contrary, a JNK inhibitor could suppress the cell death induced by this compound. Our findings thus suggested a novel anticancer mechanism of a benzo(1,3)dioxol‑based derivative of sulfonamide for colorectal cancer cells and may have therapeutic potential for the treatment of colorectal cancer; however, further investigation is required.

Novel quinazoline-based sulfonamide derivative (3D) induces apoptosis in colorectal cancer by inhibiting JAK2-STAT3 pathway

Introduction

Colorectal cancer (CRC) is a major worldwide health problem owing to its high prevalence and mortality rate. Developments in screening, prevention, biomarker, personalized therapies and chemotherapy have improved detection and treatment. However, despite these advances, many patients with advanced metastatic tumors still succumb to the disease. New anticancer agents are needed for treating advanced stage CRC as most of the deaths occur due to cancer metastasis. A recently developed novel sulfonamide derivative 4-((2-(4-(dimethylamino) phenyl)quinazolin-4-yl)amino)benzenesulfonamide (3D) has shown potent antitumor effect; however, the mechanism underlying the antitumor effect remains unknown.

Materials and methods

3D-mediated inhibition on cell viability was evaluated by MTT and real-time cell proliferation was measured by xCelligence RTDP instrument. Western blotting was used to measure pro-apoptotic, anti-apoptotic proteins and JAK2-STAT3 phosphorylation. Flow cytometry was used to measure ROS production and apoptosis.

Results

Our study revealed that 3D treatment significantly reduced the viability of human CRC cells HT-29 and SW620. Furthermore, 3D treatment induced the generation of reactive oxygen species (ROS) in human CRC cells. Confirming our observation, N-acetylcysteine significantly inhibited apoptosis. This is further evidenced by the induction of p53 and Bax; release of cytochrome c; activation of caspase-9, caspase-7 and caspase-3; and cleavage of PARP in 3D-treated cells. This compound was found to have a significant effect on the inhibition of antiapoptotic proteins Bcl2 and BclxL. The results further demonstrate that 3D inhibits JAK2–STAT3 pathway by decreasing the constitutive and IL-6-induced phosphorylation of STAT3. 3D also decreases STAT3 target genes such as cyclin D1 and survivin. Furthermore, a combination study of 3D with doxorubicin (Dox) also showed more potent effects than single treatment of Dox in the inhibition of cell viability.

Conclusion

Taken together, these findings indicate that 3D induces ROS-mediated apoptosis and inhibits JAK2–STAT3 signaling in CRC.

Novel derivative of aminobenzenesulfonamide (3c) induces apoptosis in colorectal cancer cells through ROS generation and inhibits cell migration

BACKGROUND

Colorectal cancer (CRC) is the 3^rd most common type of cancer worldwide. New anti-cancer agents are needed for treating late stage colorectal cancer as most of the deaths occur due to cancer metastasis. A recently developed compound, 3c has shown to have potent antitumor effect; however the mechanism underlying the antitumor effect remains unknown.

METHODS

3c-induced inhibition of proliferation was measured in the absence and presence NAC using MTT in HT-29 and SW620 cells and xCELLigence RTCA DP instrument. 3c-induced apoptotic studies were performed using flow cytometry. 3c-induced redox alterations were measured by ROS production using fluorescence plate reader and flow cytometry and mitochondrial membrane potential by flow cytometry; NADPH and GSH levels were determined by colorimetric assays. Bcl2 family protein expression and cytochrome c release and PARP activation was done by western blotting. Caspase activation was measured by ELISA. Cell migration assay was done using the real time xCELLigence RTCA DP system in SW620 cells and wound healing assay in HT-29.

RESULTS

Many anticancer therapeutics exert their effects by inducing reactive oxygen species (ROS). In this study, we demonstrate that 3c-induced inhibition of cell proliferation is reversed by the antioxidant, N-acetylcysteine, suggesting that 3c acts via increased production of ROS in HT-29 cells. This was confirmed by the direct measurement of ROS in 3c-treated colorectal cancer cells. Additionally, treatment with 3c resulted in decreased NADPH and glutathione levels in HT-29 cells. Further, investigation of the apoptotic pathway showed increased release of cytochrome c resulting in the activation of caspase-9, which in turn activated caspase-3 and -6. 3c also (i) increased p53 and Bax expression, (ii) decreased Bcl2 and BclxL expression and (iii) induced PARP cleavage in human colorectal cancer cells. Confirming our observations, NAC significantly inhibited induction of apoptosis, ROS production, cytochrome c release and PARP cleavage. The results further demonstrate that 3c inhibits cell migration by modulating EMT markers and inhibiting TGFβ-induced phosphorylation of Smad2 and Samd3.

CONCLUSIONS

Our findings thus demonstrate that 3c disrupts redox balance in colorectal cancer cells and support the notion that this agent may be effective for the treatment of colorectal cancer.