A Selection of Recent Targeted Cancer Treatment Research

I'm not overly worried about cancer, or at least not in comparison to all of the other things likely to cause me pain, suffering, and death a couple of decades from now. I think that present work on targeted cell killing technologies will lead to a suite of treatments that are robust enough, therapies and infrastructure that will reduce the risks and consequences of cancer to an acceptably low level over the period of time in which we will be availing ourselves of the first generation of rejuvenation treatments. Or at least that will be the case if matters proceed well and growth continues on an accelerating path for those fields of aging and longevity science most likely to produce meaningful results.

The big risk here is the same as for any nascent technological revolution: that the world continues to focus on things that don't really matter all that much, a category which includes a lot of the mainstream aging science, sad to say, and thus the rejuvenation research community fails to grow and fails to realize useful treatments in time for my old age in the 2040s. I think that the odds of this failure coming to pass are much higher than the chances of the cancer community failing to deliver over the same time frame. I will be astounded and unhappy in equal measure to find that cancer has not been wrestled into a state akin to that of tuberculosis by 2040: a minor threat, once a dreadful killer, kept caged by advanced medical technology.

Thus I am not overly worried about cancer; it is a concern in life, just like road safety and general health, but not an overwhelming concern. As is the case for stem cell medicine cancer research is enormously well funded. It is not a field that needs any more help and support than it already has in order to make good progress towards bringing cancer under medical control - though of course this is the case because plenty of people don't agree with me, and are willing to step up and do something about it. Researchers are well on the way to realizing the next generation of treatments that will soon enough replace chemotherapy and radiotherapy, consisting of far more effective targeted approaches that employ nanoparticles, immune cells, bacteria, and viruses to destroy cancer cells with minimal side-effects.

Here are a few representative papers and research results from the cancer community, published recently:

Oncolytic viral therapy: targeting cancer stem cells

Cancer stem cells (CSCs) are defined as rare populations of tumor-initiating cancer cells that are capable of both self-renewal and differentiation. Extensive research is currently underway to develop therapeutics that target CSCs for cancer therapy, due to their critical role in tumorigenesis, as well as their resistance to chemotherapy and radiotherapy.

To this end, oncolytic viruses targeting unique CSC markers, signaling pathways, or the pro-tumor CSC niche offer promising potential as CSCs-destroying agents/therapeutics. We provide a summary of existing knowledge on the biology of CSCs, including their markers and their niche thought to comprise the tumor microenvironment, and then we provide a critical analysis of the potential for targeting CSCs with oncolytic viruses, including herpes simplex virus-1, adenovirus, measles virus, reovirus, and vaccinia virus.

Herpes-loaded stem cells used to kill brain tumors

Cancer-killing or oncolytic viruses have been used in numerous phase 1 and 2 clinical trials for brain tumors but with limited success. In preclinical studies, oncolytic herpes simplex viruses seemed especially promising, as they naturally infect dividing brain cells. However, the therapy hasn't translated as well for human patients. The problem previous researchers couldn't overcome was how to keep the herpes viruses at the tumor site long enough to work.

[Researchers] turned to mesenchymal stem cells (MSCs) - a type of stem cell that gives rise to bone marrow tissue - which have been very attractive drug delivery vehicles because they trigger a minimal immune response and can be utilized to carry oncolytic viruses. [Researchers] loaded the herpes virus into human MSCs and injected the cells into glioblastoma tumors developed in mice. Using multiple imaging markers, it was possible to watch the virus as it passed from the stem cells to the first layer of brain tumor cells and subsequently into all of the tumor cells.

Using imaging proteins to watch in real time how the virus combated the cancer, [researchers] noticed that the gel kept the stem cells alive longer, which allowed the virus to replicate and kill any residual cancer cells that were not cut out during the debulking surgery. This translated into a higher survival rate for mice that received the gel-encapsulated stem cells.

New Method Sneaks Drugs into Cancer Cells Before Triggering Release

Biomedical engineering researchers have developed an anti-cancer drug delivery method that essentially smuggles the drug into a cancer cell before triggering its release. The method can be likened to keeping a cancer-killing bomb and its detonator separate until they are inside a cancer cell, where they then combine to destroy the cell.

The technique uses nanoscale lipid-based capsules, or liposomes, to deliver both the drug and the release mechanism into cancer cells. One set of liposomes contains adenosine-5'-triphosphate (ATP), the so-called "energy molecule." A second set of liposomes contains an anti-cancer drug called doxorubicin (Dox) that is embedded in a complex of DNA molecules. When the DNA molecules come into contact with high levels of ATP, they unfold and release the Dox. The surface of the liposomes is integrated with positively charged lipids or peptides, which act as corkscrews to introduce the liposomes into cancer cells.

In a mouse model, the researchers found that the new technique significantly decreased the size of breast cancer tumors compared to treatment that used Dox without the nanoscale liposomes.

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