Chemotherapy: a double-edged sword in cancer treatment.

Chemotherapy is a well-known and effective treatment for different cancers; unfortunately, it has not been as efficient in the eradication of all cancer cells as been expected. The mechanism of this failure was not fully clarified, yet. Meanwhile, alterations in the physiologic conditions of the tumor microenvironment (TME) were suggested as one of the underlying possibilities. Chemotherapy drugs can activate multiple signaling pathways and augment the secretion of inflammatory mediators. Inflammation may show two opposite roles in the TME. On the one hand, inflammation, as an innate immune response, tries to suppress tumor growth but on the other hand, it might be not powerful enough to eradicate the cancer cells and even it can provide appropriate conditions for cancer promotion and relapse as well. Therefore, the administration of mild anti-inflammatory drugs during chemotherapy might result in more successful clinical results. Here, we will review and discuss this hypothesis. Most chemotherapy agents are triggers of inflammation in the tumor microenvironment through inducing the production of senescence-associated secretory phenotype (SASP) molecules. Some chemotherapy agents can induce systematic inflammation by provoking TLR4 signaling or triggering IL-1B secretion through the inflammasome pathway. NF-kB and MAPK are key signaling pathways of inflammation and could be activated by several chemotherapy drugs. Furthermore, inflammation can play a key role in cancer development, metastasis and exacerbation.

Hypoxia effects on oncolytic virotherapy in Cancer: Friend or Foe?

Researchers have tried to find novel strategies for cancer treatment in the past decades. Among the utilized methods, administering oncolytic viruses (OVs) alone or combined with other anticancer therapeutic approaches has had promising outcomes, especially in solid tumors. Infecting the tumor cells by these viruses can lead to direct lysis or induction of immune responses. However, the immunosuppressive tumor microenvironment (TME) is considered a significant challenge for oncolytic virotherapy in treating cancer. Based on OV type, hypoxic conditions in the TME can accelerate or repress virus replication. Therefore, genetic manipulation of OVs or other molecular modifications to reduce hypoxia can induce antitumor responses. Moreover, using OVs with tumor lysis capability in the hypoxic TME may be an attractive strategy to overcome the limitations of the therapy. This review summarizes the latest information available in the field of cancer virotherapy and discusses the dual effect of hypoxia on different types of OVs to optimize available related therapeutic methods.

Oridonin Could Inhibit Inflammation and T-cell Immunoglobulin and Mucin-3/Galectin-9 (TIM-3/Gal-9) Autocrine Loop in the Acute Myeloid Leukemia Cell Line (U937) as Compared to Doxorubicin.

The T-cell immunoglobulin and mucin-3 (TIM-3)/galectin-9 (Gal-9) autocrine loop is an indispensable signaling in acute myeloid leukemia (AML) cells, which induces their self-renewal through activation of nuclear factor-kappa b (NF-kB) and ß-catenin pathways. In this study, we evaluated the effects of oridonin and doxorubicin on the TIM-3/Gal-9 autocrine loop. We also evaluated oridonin anti-inflammatory and anti-cancer properties on U937 cells, as an AML cell line in comparison to doxorubicin as a common anthracycline drug for AML treatment. Cell counting kit-8 (CCK-8) was applied to evaluate the cytotoxicity of oridonin and doxorubicin on U937 cells and also to determine the impact of galectin-9 (Gal-9) on their proliferation. The effects of oridonin and doxorubicin on Gal-9, TIM-3, and interleukin-1ß (IL-1ß) gene expression were determined by real-time polymerase chain reaction (RT-PCR). The Gal-9 secretion level was measured by enzyme-linked immunosorbent assay (ELISA) and activation of NF-kB pathway was assessed by western blotting. In a dose-dependent manner, oridonin and doxorubicin were capable to eradicate U937 cells while Gal-9 expanded them. Following the treatment of U937 cells with oridonin, the expression of Gal-9, TIM-3, and IL-1ß genes was down-regulated, and the Gal-9 secretion and NF-kB phosphorylation were diminished, whereas doxorubicin increased all of these factors. Doxorubicin is a common treatment agent in AML, but it may induce inflammation and up-regulate the TIM3/Gal-9 autocrine loop, consequently can enhance the possibility of disease relapse. Meanwhile, oridonin is capable to inhibit the essential signaling pathways in AML cells and reduce the inflammation and expansion of tumor cells and postpone AML recurrence.