A new gold-based drug can slow tumor growth in animals by 82% and attack cancers more selectively than standard chemotherapy drugs, according to a study by Australian and Indian researchers.
The RMIT University study published in the European Journal of Medicinal Chemistry reveals a new gold-based compound that is 27 times more potent against cervical cancer cells in the laboratory than the standard chemotherapy drug cisplatin.
It was also 3.5 times more effective against prostate cancer and 7.5 times more effective against fibrosarcoma cells in the laboratory.
In mouse studies, the gold compound reduced cervical cancer tumor growth by 82%, compared to 29% for cisplatin.
Project leader at RMIT, Distinguished Professor Suresh Bhargava AM, said it marked a promising step towards alternatives to platinum-based cancer drugs.
“These newly synthesized compounds demonstrate remarkable anti-cancer potential, outperforming current treatments in a number of important aspects, including their selectivity to target cancer cells,” said Bhargava, director of RMIT’s Center for Advanced Materials and Industrial Chemistry.
“Although human trials are still some way off, we are very encouraged by these results.”
The gold-based compound is now protected by a US patent and ready for further development towards possible clinical application.
Towards a more specific and less toxic treatment
Gold is famous for being the noblest of all metals because it has little or no reaction when it meets other substances; a property that makes it perfect for wedding rings and coins.
However, the gold compound used in this study is a chemically adapted form known as Gold(I), designed to be highly reactive and biologically active.
This chemically reactive form was then adapted to interact with an enzyme abundant in cancer cells, known as thioredoxin reductase.
By blocking the activity of this protein, the gold compound effectively deactivates cancer cells before they can multiply or develop resistance to drugs.
Bhargava said this highly targeted approach minimizes the toxic side effects seen with platinum-based cisplatin, which attacks DNA and damages both healthy and cancerous cells.
“Its selectivity to target cancer cells, combined with reduced systemic toxicity, points to a future in which treatments will be more effective and much less harmful,” Bhargava said.
This specific form of gold was also shown to be more stable than those used in previous studies, allowing the compound to remain intact while reaching the tumor site.
Co-director of the project at RMIT, Distinguished Professor Magdalena Plebanski, said that along with this ability to block protein activity, the compound also had another weapon in its anti-cancer arsenal.
In studies with zebrafish, it was shown to stop the formation of new blood vessels that tumors need to grow.
This was the first time that one of the team’s various gold compounds showed this effect, known as antiangiogenesis.
The drug’s effectiveness by using these two attacks simultaneously was demonstrated against a variety of cancer cells.
This included ovarian cancer cells, which are known to develop resistance to cisplatin treatment in many cases.
“Drug resistance is a major challenge in cancer therapy,” said Plebanski, who heads RMIT’s Cancer, Aging and Vaccines Laboratory.
“Seeing that our gold compound has such strong efficacy against difficult-to-treat ovarian cancer cells is an important step toward treating recurrent cancers and metastases.”
Regional collaboration is a key enabler
The dedicated RMIT team is collaborating with scientists at the Indian Institute of Chemical Technology (IICT) in Hyderabad under a $2 million grant from the Australia-India Strategic Research Fund.
The first author of the latest study, Dr Srinivasa Reddy, initially graduated from RMIT’s joint PhD program with the IICT and now plays an active role in the collaborative project.
Meanwhile, RMIT Vice-Chancellor’s Research Fellow Dr Ruchika Ojha has been supporting Bhargava in building and leading his molecular engineering group to continue advancing innovative research into gold-based therapies in the future.
“I am proud to continue Professor Bhargava’s golden legacy, ensuring that his pioneering contributions to this field continue to inspire groundbreaking discoveries,” Ojha said.
Bhargava said harnessing the best minds and technical infrastructure in Australia and India was critical to making a significant difference in the fight against cancer.
Gold has been a cornerstone of Indian Ayurvedic treatments for centuries, famous for its healing properties.
Today, gold-based cancer treatments are gaining ground globally, with advances such as the repurposing of the anti-arthritic drug auranofin, which is now showing promise in clinical trials for oncology.
“We know that gold is easily accepted by the human body and we know that it has been used for thousands of years to treat various conditions,” Bhargava said.
“Basically, gold has been market tested, but not scientifically validated.
“Our work is helping to provide the missing evidence base, as well as generate new families of molecules tailored to amplify the natural healing properties of gold,” he said.
Support for the industry is worth its weight in gold
RMIT’s research in this field over a long period has attracted the attention of the gold industry.
In October, Pallion subsidiary ABC Bullion pledged an annual donation of 250 grams of pure Australian gold (valued at more than A$30,000) to support research.
Representatives from Canada’s third largest gold producer, Agnico Eagle Mines, also visited RMIT laboratories to explore opportunities for collaboration.
“These endorsements highlight the social and scientific impact of our research,” Bhargava said.
“There is a recognition that this is not just a scientific advance but a step toward addressing a global health challenge and people want to be part of that.”
This innovative project led by Bhargava and Pebanski brings together a dynamic team of young scientists, including Dr. Srinivasa Reddy, Dr. Steven Priver, Dr. Ruchika Ojha, Dr. Ranjith Jakku and Dr. Tayebeh Hosseinnejad. Meanwhile, six doctoral students from India, Germany, Australia, Bangladesh and Mexico have joined the effort, further strengthening the global collaboration.