A Promising Anti-Cancer Compound

 

New approaches in cancer therapy that facilitate selective targeting of cancers have been emerging in recent years. Apoptin represents a new anti-cancer tool in such new approaches with great potentials. Two routes can be taken using Apoptin or its encoding cDNA, i.e. as protein therapy or gene therapy.

A research article published on 21 June 2008, in the World Journal of Gastroenterology refers. The research team led by Prof. Duan from Life Sciences Institute of Northwest University used molecular biology,to generated a cDNA construct of SP-Tat-Apoptin fusion. Cancer cells transfected with this construct would express the recombinant Apoptin and apoptosis would be induced in them. By incorporating a synthetic signal peptide authors also expected Apoptin to be secreted outside of the transfected cells as Tat-Apoptin fusion protein and re-enter adjacent untransfected HepG2 cells, enabling the construct to act as both protein and gene therapeutic agent and increasing the potency of Apoptin in cancer therapy.

Having a synthetic signal peptide, the recombinant Apoptin was able to be secreted outside of the transfected cells and re-enter adjacent untransfected HepG2 cells. The recombinant protein was detected in the cytoplasm in HepG2 and HUVEC cells shortly after co-culture of the cells with the cell-free supernatant of the transfected CHO cell culture, indicating the secreted Tat-Apoptin fusion protein contained in the CHO cell culture media was able to enter these cells. The fusion protein was later found in the nucleus in HepG2 cells and induced HepG2 cell apoptosis.  The new secretory characteristic increased the possibility of Apoptin being used in cancer gene therapy. However, there are still a large number of unanswered questions regarding the mechanisms and therapeutic usage of Apoptin, and further studies are certainly required.

There are more HCC cell line used to confirm the results in our study, for example, Bel-7402 HCC cell line. The result about Bel-7402 will be discussed in future. Meanwhile in HUVEC cells, SP-Tat-Apoptin remained in the cytoplasm and no induction of apoptosis above the background level was observed. 'Open Cancer Surgery Set To Become A Thing Of The Past' The surgeon's knife is playing an ever smaller role in the treatment of cancer, as it is replaced by increasingly efficient and safe radiation therapy techniques. Progress in radiation technology will also lead to better detection rates for cancer. This is according to Professor Freek Beekman, who will give his inaugural speech at TU Delft on Wednesday, 24 September.

In his inaugural address, Kanker, krijg de straling , Professor Beekman says that radiation in the form of photons or particles is playing an increasingly important role in the detection and treatment of cancer. The low concentrations of radioactive molecules which gather in tumours, known as 'tumour seekers', show up well with techniques such as Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT). Such techniques mean that tumours can be discovered earlier more often than using X-rays, and it is also more often possible to ascertain properties of tumour cells without removing a sample of the tissue. Doctors can choose the best treatment for the individual patient more quickly and easily.

Removal
Destroying tumours by using radiation, rather than chemotherapy and operations, is also becoming an ever more common method of treatment and, Beekman says, the accuracy of this kind of therapy has improved considerably in recent years. When cancer is treated using external beams of radiation (as in radiotherapy), it is actually not only the tumour that is exposed to large amounts of radiation, but also any healthy tissue that is in the way of the beam. 'One example of a very powerful emerging technique is the use of a radiation beam consisting of particles (protons), instead of photons. This kind of beam reaches its peak intensity at the site of the tumour. This greatly reduces radiation damage in healthy tissue around the tumour.' Finally, it is increasingly possible to treat tumours internally, for example by using tumour seekers that emit particles and destroy the tumour on the spot. If this kind of treatment only reaches the tumour and avoids harming healthy tissue, it will make this method superior to proton therapy.

U - SPECT
At TU Delft, Beekman will focus particularly on improving medical instruments, such as the U-SPECT scanner he developed himself. This Ultra-high resolution Single Photon Emission Computed Tomographer has significant advantages over other scanning techniques. The challenge is now to make the U-SPECT more precise and more versatile and use it to create better tumour seekers. The U-SPECT is now only available for use with small laboratory animals, but a version for humans is in the design phase. The diagnosis and treatment of cancer could, according to Beekman, be greatly improved by sharper SPECT images of patients. Various tracers mean that metastases, for example, are visible more quickly. We also hope that the effectiveness of chemotherapy can be seen very soon after beginning treatment by using the right tumour seekers, or even stop therapy with little chance of success from being started at all.

Medical Delta
'The current quest for more efficient medical screening therapies, radiotherapy and tumour seekers is gradually leading towards better treatments for cancer,' says Beekman. 'Progress is gradual and it must be said that there are still a number of technical obstacles. But on the other hand, the type of instrumentation we are talking about here is not always rocket science. The problems we face are mostly not insurmountable.'

Improved technology means that we still have a hope of success in the detection and treatment of cancer. Beekman says it is important that hospitals and engineers work closely together. The TU Delft is a part of Medical Delta, which provides the structure for this cooperation to take place. In Medical Delta, TU Delft cooperates with Erasmus University, the University of Leiden and their teaching hospitals.