A study highlights the anti-tumor activity of curcumin on stomach cancer

Curcumin is widely used to impart color and flavor to foods, but scientists have discovered that this yellow powder is derived from the roots of turmeric (Turmeric Longa) can also help prevent or fight stomach cancer.

The study carried out by researchers from the Federal University of São Paulo (UNIFESP) and the Federal University of Para (UFPA) in Brazil allowed to determine the possible therapeutic effects of this pigment and other bioactive compounds present in foods on stomach cancer, the third and fifth most common cancers. type of cancer in Brazilian men and women, respectively.

The study was part of a thematic project supported by the São Paulo Research Foundation – FAPESP. His conclusions were published in the journal epigenomics.

"We undertook an extensive review of the scientific literature on all the nutrients and bioactive compounds that can prevent or treat stomach cancer and discovered that curcumin is one of them," said Danielle Queiroz Calcagno, professor at UFPA and first author of the study, Told.

According to Calcagno, who conducted a postdoctoral research at UNIFESP with a FAPESP grant, compounds such as cholecalciferol (a form of vitamin D), resveratrol (a polyphenol) and quercetin can prevent or combat the stomach cancer as they are natural regulators of the activity of histones.

Histones are proteins in the cell nuclei that organize the double helix of DNA into structural units called nucleosomes. Each nucleosome is made of DNA wrapped as a coil around eight histone proteins (a histone octamer) to compact the DNA so that it inserts in the cell, where it is packed in chromatin.

Post-translational chemical modification of the amino acid chain in these proteins, such as acetylation (introduction of an acetyl group) or methylation (addition of a methyl group), can affect chromatin compaction and thus gene expression.

"If the histones are acetylated, for example, the chromatin will be less condensed and a gene located in a region of the DNA segment inside will be available to be expressed.On the other hand, if the histones are not acetylated, the chromatin be more condensed, and the gene will not be expressed, "explained Calgano.

Research conducted in recent years suggests that post-translational modification of histones causes alterations in gene expression without affecting the DNA sequence. These epigenetic variations influence the development of different types of cancer.

To determine if this hypothesis also applied to stomach cancer, several groups of researchers coordinated by Marília de Arruda Cardoso Smith, professor at UNIFESP, studied the acetylation patterns of histones in samples of stomach cells taken from healthy individuals and in patients with stomach cancer.

The researchers found that the cells of patients with stomach cancer had alterations in the histone acetyltransferase (HAT) expression profile and histone deacetylases (HDAC). These alterations are epigenetic and affect the structure and integrity of the genome of many tumors, including stomach cancer.

As recent research has also shown that nutrients and bioactive compounds can regulate the activity of HATs and HDACs, scientists at UNIFESP and UFPA have decided to identify those which could influence the acetylation of histones and thus contribute to the prevention of cancer of the stomach or even to the treatment of the disease.

In addition to curcumin, cholecalciferol, resveratrol (present mainly in grape seeds and red wine), quercetin (abundant in apples, broccoli and onions), garcinol (isolated from the bark of corn) have also played a key role in modulating the activity of histones kokum, Garcinia indica) and sodium butyrate (produced by intestinal bacteria via fermenting dietary fiber).

"These compounds can promote the activation or repression of genes involved in the development of stomach cancer by promoting or inhibiting histone acetylation," said Calcagno.

Curcumin, for example, primarily influences histone modifications by inhibiting HAT and HDACs in order to suppress the proliferation of cancer cells and induce apoptosis (programmed cell death). Garcinol, whose chemical structure resembles that of curcumin, inhibits HAT and helps prevent stomach cancer by neutralizing free radicals.

"We are now considering clarifying the anticancer and epigenetic effects of bioactive compounds derived from plants in the Amazon, such as acai [Euterpe oleracea] and Nanche or Hogberry [Byrsonima crbadifolia], with a view to their future use in the prevention and treatment of stomach cancer, "said Calcagno.